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ALS Reviews 2002

(58 References)

Balcar, V. J. (2002). "Molecular pharmacology of the Na+-dependent transport of acidic amino acids in the mammalian central nervous system." Biol Pharm Bull 25(3): 291-301.

            The Na+-dependent transport of L-glutamate (GluT) has been identified in brain tissue more than thirty years ago. Neurochemical studies, performed in various experimental models during 1970's, defined the basic rules for the selection or synthesis of GluT-specific substrates and inhibitors. The protein molecules (transporters) that mediate the translocation of the substrates across the plasma membrane have been cloned and studied during the last ten years. The sites on the transporters that bind the substrates favour glutamate-like or aspartate-like molecules with one positively charged and two negatively charged ionised groups. Substituents at C3 and C4 are often tolerated but substitutions at C2 or alterations of the ionisable groups usually impede the binding. The substrate binding sites display an "anomalous" selectivity towards stereoisomers. These structural requirements are shared by all Na+-dependent glutamate transporters thus making the design of transporter-selective ligands a challenging task. Moreover, the molecular mechanisms of the transport have not yet been adequately elucidated. Data from a wide variety of experimental studies strongly indicate that Na+-dependent GluT regulates the functioning of the glutamatergic excitatory synapses-the most important rapid inter-neuronal signalling system in the mammalian brain. Altered structural and/or functional properties of the Na+-dependent glutamate transporters have been implicated in the damage to the brain tissue following cerebral ischaemia and in the progressive loss of neurons in conditions such as Alzheimer dementia and amyotrophic lateral sclerosis. Furthermore, it seems that fine-tuning of glutamatergic neurotransmission by regulating the Na+-dependent GluT could be useful in the therapy of schizophrenia.

Beal, M. F. (2002). "Coenzyme Q10 as a possible treatment for neurodegenerative diseases." Free Radic Res 36(4): 455-60.

            Coenzyme Q10 (CoQ10) is an essential cofactor of the electron transport gene as well as an important antioxidant, which is particularly effective within mitochondria. A number of prior studies have shown that it can exert efficacy in treating patients with known mitochondrial disorders. We investigated the potential usefulness of coenzyme Q10 in animal models of Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD). It has been demonstrated that CoQ10 can protect against striatal lesions produced by the mitochondrial toxins malonate and 3-nitropropionic acid. These toxins have been utilized to model the striatal pathology, which occurs in HD. It also protects against 1-methyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity in mice. CoQ10 significantly extended survival in a transgenic mouse model of ALS. CoQ10 can significantly extend survival, delay motor deficits and delay weight loss and attenuate the development of striatal atrophy in a transgenic mouse model of HD. In this mouse model, it showed additive efficacy when combined with the N-methyl-D-aspartate (NMDA) receptor antagonist, remacemide. CoQ10 is presently being studied as a potential treatment for early PD as well as in combination with remacemide as a potential treatment for HD.

Beal, M. F. (2002). "Oxidatively modified proteins in aging and disease." Free Radic Biol Med 32(9): 797-803.

            There is a large body of evidence implicating oxidative damage in the pathogenesis of both normal aging and neurodegenerative diseases. Oxidative damage to proteins has been well established. Although there are a large number of potential oxidative modifications only a few have been systematically studied. The most frequently studied marker of oxidative damage to proteins is protein carbonyl groups. 3-Nitrotyrosine is thought to be a relatively specific marker of oxidative damage mediated by peroxynitrite. Increased concentrations of both protein carbonyls and 3-nitrotyrosine have been documented in both normal aging as well as in Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). These findings help to provide a rationale for trials of antioxidants in neurodegenerative diseases.

Bromberg, M. B. (2002). "Diagnostic criteria and outcome measurement of amyotrophic lateral sclerosis." Adv Neurol 88: 53-62.

            ALS is a most challenging disease. Accurate diagnostic criteria are well along in refinement, and experience with patients who are at the limits of the criteria should be presented to increase our comfort with the limits of ALS or motor neuron disease. As our understanding of the pathophysiology is further refined, there will be new drugs to test. It will be important to have sensitive clinical and electrophysiologic measures available to detect changes in the rate of progression. When effective drugs are identified, they will, in addition to helping patients, lend support to proposed mechanisms. Charcot would be impressed with our advances in the ability to detect and follow upper and lower motor neuron loss, but would urge us to press on in our clinical endeavors.

Bruijn, L. I. (2002). "Amyotrophic lateral sclerosis: from disease mechanisms to therapies." Biotechniques 32(5): 1112, 1114, 1116 passim.

Butterfield, D. A., A. Castegna, et al. (2002). "Vitamin E and neurodegenerative disorders associated with oxidative stress." Nutr Neurosci 5(4): 229-39.

            Several neurodegenerative disorders are associated with oxidative stress that is manifested by lipid peroxidation, protein oxidation and other markers. Included in these disorders in which oxidative stress is thought to play an important role in their pathogenesis are Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), tardive dyskinesia, Huntington's disease (HD), and multiple sclerosis. This review presents some of the chemistry of vitamin E as an antioxidant and summarizes studies in which vitamin E has been employed in these disorders and models thereof.

Christen, Y. (2002). "[Proteins and mutations: a new vision (molecular) of neurodegenerative diseases]." J Soc Biol 196(1): 85-94.

            Neurodegenerative diseases have long been considered to be poorly defined, misunderstood, and inadequately treated. In recent years, research on Alzheimer's disease has led to numerous advances that have improved our understanding of this form of dementia and also of the entire category of neurodegenerative diseases. It now appears that numerous neurodegenerative diseases of the central nervous system correspond to the aggregation of specific proteins: beta-amyloid in Alzheimer disease, tau protein in Alzheimer disease, fronto-temporal dementia, progressive supranuclear palsy and corticobasal degeneration, alpha-synuclein in Parkinson disease and Lewy body dementia, PrP protein in prion diseases, SOD in amyotrophic lateral sclerosis, polyglutamine expansions in Huntington's disease and other diseases, etc. It is remarkable that in all these cases mutations have been identified for genes coding for these proteins and able to cause the disease and, moreover, that the introduction of the corresponding gene into transgenic mice (or other transgenic animals) has made it possible to create animal models of these conditions. This suggests that the proteins in question play a determinative role in the pathogenesis of these diseases and are not simply consequences of it. Neurodegenerative diseases are proteinopathies. But they are also networkopathies because the neuronal proteins are organized in functional networks. We must also note that all these diseases are associated with the process of aging, for they do not appear in the young. This fact suggests that the anomaly (genetic or otherwise) concerning a given protein does not suffice by itself to induce the disease process. Many observations suggest that the additional event involved, common to all neurodegenerative conditions, may be the intervention of free radicals. We thus propose here the theory that the diversity of neurodegenerative diseases is explained by the combination of two pathogenic events: one specific and associated with the aggregation of a particular protein in the nervous system, the other, non-specific and associated with aging and with the production and harmful actions of free radicals. This unified interpretation leads directly to treatment hypotheses: the development of drugs capable either of inhibiting the production or aggregation of proteins specifically implicated in diverse diseases (or promoting their elimination) or of inhibiting the production or action of free radicals in the nervous system. The former should target one of these various diseases, and the latter should act on a wide range of diseases. The two approaches may conceivably be combined.

Clark, J. E., A. Brennan, et al. (2002). "Novel trends in orphan market drug discovery: amyotrophic lateral sclerosis as a case study." Front Biosci 7: c83-96.

            As new lead discovery technologies of high throughput screening and rational drug design have been incorporated into pharmaceutical and biotechnology drug discovery programs, researchers have focused on the applying these new technologies in diseases traditionally neglected by for-profit drug discovery efforts. This article reviews general trends in orphan disease lead discovery, identifies best practices of orphan market drug discovery and provides an overview of recent ALS lead discovery programs and drug development according to these metrics. Best practices in orphan market drug discovery embodied by programs like the NIH Anticonvulsant Screening Program include the (1) management of timelines and priorities, (2) engagement of for-profit partners, (3) creative application of technology, (4) collaboration, and (5) flexibility. Recent trends in ALS lead discovery have been shaped not only by the predominance of animal models of disease over in vitro models, but also by the successes and best practices of these earlier orphan market drug discovery programs. The ALS Treatment Initiative, the Johns Hopkins Center for ALS Research, the ALS Association, and the ALS Therapy Development Foundation have all initiated lead discovery programs in the past several years which seek to utilize existing experimental models of the disease and challenge assumptions about the linear nature of the lead discovery and development process. The compounds currently in clinical evaluation for ALS were identified as leads from a variety of sources, further reinforcing the transforming effect these new lead discovery programs have had on drug discovery and development in ALS. We conclude our review with an overview of the challenges and opportunities lead discovery in ALS currently faces, ultimately concluding that ALS lead discovery, and indeed orphan market drug discovery in general, would most benefit from more centralized lead discovery management, expanded national access to core facilities for lead discovery, and matrixed simultaneous screening of multiple compounds for multiple neglected diseases.

Cox, P. A. and O. W. Sacks (2002). "Cycad neurotoxins, consumption of flying foxes, and ALS-PDC disease in Guam." Neurology 58(6): 956-9.

            The Chamorro people of Guam have been afflicted with a complex of neurodegenerative diseases (now known as ALS-PDC) with similarities to ALS, AD, and PD at a far higher rate than other populations throughout the world. Chamorro consumption of flying foxes may have generated sufficiently high cumulative doses of plant neurotoxins to result in ALS-PDC neuropathologies, since the flying foxes forage on neurotoxic cycad seeds.

Dib, M., C. Garrel, et al. (2002). "Can malondialdehyde be used as a biological marker of progression in neurodegenerative disease?" J Neurol 249(4): 367-74.

            There is a large body of evidence that free radical-mediated oxidative damage is involved in the pathogenesis of neurodegenerative disease. Although it is unlikely that markers of such damage will have any diagnostic value, they might be of considerable interest in following disease progression and monitoring the efficacy of different treatments. Among such markers, there is evidence for the elevation of peripheral malondialdehyde levels in several neurodegenerative diseases, including Parkinson's disease, amyotrophic lateral sclerosis and Alzheimer's disease. The measurement of malondialdehyde levels, which is both simple and cheap to perform, can and should be incorporated into future clinical trials. This will allow a clearer picture to emerge as to whether malondialdehyde can be considered as a marker for the evolution of these diseases.

Esposito, E., D. Rotilio, et al. (2002). "A review of specific dietary antioxidants and the effects on biochemical mechanisms related to neurodegenerative processes." Neurobiol Aging 23(5): 719-35.

            Aging is a major risk factor for neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). An unbalanced overproduction of reactive oxygen species (ROS) may give rise to oxidative stress which can induce neuronal damage, ultimately leading to neuronal death by apoptosis or necrosis. A large body of evidence indicates that oxidative stress is involved in the pathogenesis of AD, PD, and ALS. An increasing number of studies show that nutritional antioxidants (especially Vitamin E and polyphenols) can block neuronal death in vitro, and may have therapeutic properties in animal models of neurodegenerative diseases including AD, PD, and ALS. Moreover, clinical data suggest that nutritional antioxidants might exert some protective effect against AD, PD, and ALS. In this paper, the biochemical mechanisms by which nutritional antioxidants can reduce or block neuronal death occurring in neurodegenerative disorders are reviewed. Particular emphasis will be given to the role played by the nuclear transcription factor-kappaB (NF-kappaB) in apoptosis, and in the pathogenesis of neurodegenerative disorders, such as AD, PD, and ALS. The effects of ROS and antioxidants on NF-kappaB function and their relevance in the pathophysiology of neurodegenerative diseases will also be examined.

Fiscus, R. R. (2002). "Involvement of cyclic GMP and protein kinase G in the regulation of apoptosis and survival in neural cells." Neurosignals 11(4): 175-90.

            Our current understanding of nitric oxide (NO), cyclic GMP (cGMP) and protein kinase G (PKG) signaling pathways in the nervous systems has its origins in the early studies conducted on vascular tissues during the late 1970s and early to mid-1980s. The pioneering research into the NO/cGMP/PKG pathway in blood vessels conducted by the laboratories of Drs. Ferid Murad, Louis Ignarro and Robert Furchgott ultimately led to the awarding of the 1998 Nobel Prize in Physiology or Medicine to these three scientists. On the basis of further pioneering studies by Drs. John Garthwaite, Solomon Snyder, Steven Vincent and many other neuroscientists during the late 1980s and throughout the 1990s, it became recognized that NO serves as a neurotransmitter/neuromodulator in the central and peripheral nervous systems and that certain neural cells possess a cGMP signaling pathway similar to that in vascular smooth muscle cells. Although NO (at high concentrations) is toxic and thought to participate in neuronal cell death during stroke and neurodegenerative diseases (e.g. amyotrophic lateral sclerosis, Alzheimer's disease, HIV dementia and Parkinson's disease), recent evidence suggests that NO at low physiological concentrations can act as an antiapoptotic/prosurvival factor in certain neural cells (e.g. PC12 cells, motor neurons and neurons of dorsal root ganglia, hippocampus and sympathetic nerves). The antiapoptotic effects of NO are mediated, in part, by cGMP and a downstream target protein, PKG. Other cGMP-elevating factors (e.g. atrial and brain natriuretic peptides) and direct PKG activator (e.g. 8-bromo-cGMP) also have antiapoptotic effects which have been quantified by the new capillary electrophoresis with laser-induced fluorescence detector technology. Inhibition of soluble guanylyl cyclase and lowering of basal cGMP levels cause apoptosis in unstressed neural cells (NG108-15 and N1E-115 cells). The cGMP/PKG pathway appears to play an essential role in preventing activation of a proapoptotic pathway, thus promoting neural cell survival.

Forloni, G., L. Terreni, et al. (2002). "Protein misfolding in Alzheimer's and Parkinson's disease: genetics and molecular mechanisms." Neurobiol Aging 23(5): 957-76.

            The accumulation of altered proteins is a common pathogenic mechanism in several neurodegenerative disorders. A causal role of protein aggregation was originally proposed in Alzheimer's disease (AD) where extracellular deposition of beta-amyloid (Abeta) is the main neuropathological feature. It is now believed that intracellular deposition of aggregated proteins may be relevant in Parkinson's disease (PD), amyotrophic lateral sclerosis and polyglutamine disorders. An impairment of ubiquitin-proteasome system (UPS) appears directly involved in these disorders. We reviewed the results on the role of protein misfolding in AD and PD and the influence of mutations associated with these diseases on the expression of amyloidogenic proteins. Results of genetic screening of familial cases of AD and PD are summarized. In the familial AD population (70 subjects) we found several mutations of the presenilin 1 (PS1) gene with a frequency of 12.8% and one mutation in the gene encoding the protein precursor of amyloid (APP) (1.4%). One mutation of Parkin in the homozygous form and two in the heterozygous form were identified in our PD population. We also reported data obtained with synthetic peptides and other experimental models, for evaluation of the pathogenic role of mutations in terms of protein misfolding.

Ginsberg, G. and S. Lowe (2002). "Cost effectiveness of treatments for amyotrophic lateral sclerosis: a review of the literature." Pharmacoeconomics 20(6): 367-87.

            Amyotrophic lateral sclerosis (ALS) is a difficult to diagnose, fatal, progressive degenerative disease with an average survival time of 2 to 5 years. Percutaneous endoscopic gastrotomy (PEG) and bi-level intermittent positive pressure (BIPAP) ventilation may be the major interventions leading to longer survival of patients with ALS. Riluzole has been shown to have modest effects on survival (as opposed to functional) gains and is currently the only drug approved for the treatment of ALS. There is conflicting evidence with regard to the ability of recombinant human insulin-like growth factor (rhIGF-I) to retard ALS progression. Mechanical ventilation (via a tracheostomy tube) is expensive, but is widely used in later stage patients with ALS in the US. A review of nine cost-effectiveness studies of riluzole and one of rhIGF-I found the following: drug costs and survival gains are the major drivers of cost effectiveness; survival gains are estimated from truncated databases with a high degree of uncertainty; more accurate stage-specific utility weights based on patients who agreed to treatment are needed; case incidence-based evaluations should be carried out; cost-effectiveness ratios are insensitive to discount rates; employment and caregiver issues or externalities have been widely ignored; threshold acceptance cost-effectiveness values are ill-defined and evaluations are not generalisable to other countries because of cost and treatment style differences. On account of the high degree of uncertainty pertaining to survival gains and the relatively high costs per life years or quality-adjusted life-years gained, and while acknowledging that not every therapy has to be cost effective (e.g. orphan drugs), it is still inconclusive as to whether or not riluzole or rhIGF-1 can be considered as cost-effective therapies for ALS.

Hadano, S. (2002). "[Causative genes for familial amyotrophic lateral sclerosis]." Seikagaku 74(6): 483-9.

Hand, C. K. and G. A. Rouleau (2002). "Familial amyotrophic lateral sclerosis." Muscle Nerve 25(2): 135-59.

            The increasing complexity of the pathways implicated in the pathogenesis of familial amyotrophic lateral sclerosis (ALS) has stimulated intensive research in many directions. Genetic analysis of familial ALS has yielded six loci and one disease gene (SOD1), initially suggesting a role for free radicals in the disease process, although the mechanisms through which the mutant exerts toxicity and results in selective motor neuron death remain uncertain. Numerous studies have focused on structural elements of the affected cell, emphasizing the role of neurofilaments and peripherin and their functional disruption in disease. Other topics examined include cellular homeostasis of copper and calcium, particularly in the context of oxidative stress and the processes of protein aggregation, glutamate excitotoxicity, and apoptosis. It has become evident that there is considerable interplay between these mechanisms and, as the role of each is established, a common picture may emerge, enabling the development of more targeted therapies. This study discusses the main areas of investigation and reviews the findings.

Heath, P. R. and P. J. Shaw (2002). "Update on the glutamatergic neurotransmitter system and the role of excitotoxicity in amyotrophic lateral sclerosis." Muscle Nerve 26(4): 438-58.

            Excitotoxicity may play a role in certain disorders of the motor system thought to be caused by environmentally acquired toxins, including lathyrism and domoic acid poisoning. Motor neurons appear to be particularly susceptible to toxicity mediated via alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-kainate receptors. There is a body of evidence implicating glutamatergic toxicity as a contributory factor in the selective neuronal injury occurring in amyotrophic lateral sclerosis (ALS). Interference with glutamate-mediated toxicity is so far the only neuroprotective therapeutic strategy that has shown benefit in terms of slowing disease progression in ALS patients. Biochemical studies have shown decreased glutamate levels in central nervous system (CNS) tissue and increased levels in the cerebrospinal fluid (CSF) of ALS patients. CSF from ALS patients is toxic to neurons in culture, apparently via a mechanism involving AMPA receptor activation. There is evidence for altered expression and function of glial glutamate transporters in ALS, particularly excitatory amino acid transporter 2 (EAAT2). Abnormal splice variants of EAAT2 have been detected in human CNS. Mitochondrial dysfunction may contribute to excitotoxicity in ALS. Induction of neuronal nitric oxide synthase and cyclooxygenase 2 in ALS may also lead to significant interactions with regulation of the glutamate transmitter system. Certain features of motor neurons may predispose them to the neurodegenerative process in ALS, such as the cell size, mitochondrial activity, neurofilament content, and relative lack of certain calcium-binding proteins and molecular chaperones. Motor neurons appear vulnerable to toxicity mediated by calcium-permeable AMPA receptors. The relatively low expression of the glutamate receptor 2 (GluR2) AMPA receptor subunit and the high current density caused by the large number and density of cell surface AMPA receptors are potentially important factors that may predispose to such toxicity.

Jankowsky, J. L., A. Savonenko, et al. (2002). "Transgenic mouse models of neurodegenerative disease: opportunities for therapeutic development." Curr Neurol Neurosci Rep 2(5): 457-64.

            Neurodegenerative diseases present an extraordinary challenge for medicine due to the grave nature of these illnesses, their prevalence, and their impact on individuals and caregivers. The most common of these age-associated chronic illnesses are Alzheimer's disease (AD) and Parkinson's disease (PD); other examples include the prion disorders, amyotrophic lateral sclerosis (ALS), and the trinucleotide (CAG) repeat diseases. All of these diseases are characterized by well-defined clinical syndromes with progressive courses that reflect the dysfunction and eventual loss of specific neuronal populations. Current therapies provide only symptomatic relief; none significantly alter the course of disease. We describe here how transgenic mice designed to model these diseases have substantially contributed to the identification and validation of many promising new therapies, and conversely how they have quickly and cost effectively eliminated several targets with unrealized expectations.

Kaufmann, P. and H. Mitsumoto (2002). "Amyotrophic lateral sclerosis: objective upper motor neuron markers." Curr Neurol Neurosci Rep 2(1): 55-60.

            The diagnosis of amyotrophic lateral sclerosis (ALS) remains a clinical diagnosis. It is based on the combination of both upper and lower motor neuron signs in the neurologic examination. With several new therapeutic agents on the horizon, effective and objective disease markers for diagnosis and surrogate outcome measures in clinical trials are crucial. Whereas the presence of lower motor neuron signs on neurologic examination can be ascertained by electromyography, there is no widely accepted marker for upper motor neuron involvement. Neuroimaging changes of the corticospinal tract in ALS patients have been studied using magnetic resonance (MR) imaging, but appear to lack sensitivity and specificity. MR spectroscopy, a technique that allows one to evaluate biochemical tissue composition in vivo, has been widely used to establish the progressive decrease in N-acetylaspartate, a marker of neuronal integrity, in the course of ALS. More recently, diffusion tensor imaging, a newer MR technique, has demonstrated changes in diffusivity along the corticospinal tract in ALS patients. Metabolic aspects in the brains of ALS patients have been evaluated using positron emission tomography. Transcranial magnetic stimulation is a more established technique that evaluates the neurophysiologic integrity of upper motor neurons in ALS. This article reviews the progress that has been made over the past two decades towards establishing valid diagnostic and natural history markers of upper motor neuron involvement in ALS.

Kirkitadze, M. D., G. Bitan, et al. (2002). "Paradigm shifts in Alzheimer's disease and other neurodegenerative disorders: the emerging role of oligomeric assemblies." J Neurosci Res 69(5): 567-77.

            Alzheimer's disease (AD) is a progressive, neurodegenerative disorder characterized by amyloid deposition in the cerebral neuropil and vasculature. These amyloid deposits comprise predominantly fragments and full-length (40 or 42 residue) forms of the amyloid beta-protein (Abeta) organized into fibrillar assemblies. Compelling evidence indicates that factors that increase overall Abeta production or the ratio of longer to shorter forms, or which facilitate deposition or inhibit elimination of amyloid deposits, cause AD or are risk factors for the disease. In vitro studies have demonstrated that fibrillar Abeta has potent neurotoxic effects on cultured neurons. In vivo experiments in non-human primates have demonstrated that Abeta fibrils directly cause pathologic changes, including tau hyperphosphorylation. In concert with histologic studies revealing a lack of tissue injury in areas of the neuropil in which non-fibrillar deposits were found, these data suggested that fibril assembly was a prerequisite for Abeta-mediated neurotoxicity in vivo. Recently, however, both in vitro and in vivo studies have revealed that soluble, oligomeric forms of Abeta also have potent neurotoxic activities, and in fact, may be the proximate effectors of the neuronal injury and death occurring in AD. A paradigm shift is thus emerging that necessitates the reevaluation of the relative importance of polymeric (fibrillar) vs. oligomeric assemblies in the pathobiology of AD. In addition to AD, an increasing number of neurodegenerative disorders, including Parkinson's disease, familial British dementia, familial amyloid polyneuropathy, amyotrophic lateral sclerosis, and prion diseases, are associated with abnormal protein assembly processes. The archetypal features of the assembly-dependent neuropathogenetic effects of Abeta may thus be of relevance not only to AD but to these other disorders as well.

Knockaert, M., P. Greengard, et al. (2002). "Pharmacological inhibitors of cyclin-dependent kinases." Trends Pharmacol Sci 23(9): 417-25.

            Cyclin-dependent kinases (CDKs) regulate the cell division cycle, apoptosis, transcription and differentiation in addition to functions in the nervous system. Deregulation of CDKs in various diseases has stimulated an intensive search for selective pharmacological inhibitors of these kinases. More than 50 inhibitors have been identified, among which >20 have been co-crystallized with CDK2. These inhibitors all target the ATP-binding pocket of the catalytic site of the kinase. The actual selectivity of most known CDK inhibitors, and thus the underlying mechanism of their cellular effects, is poorly known. Pharmacological inhibitors of CDKs are currently being evaluated for therapeutic use against cancer, alopecia, neurodegenerative disorders (e.g. Alzheimer's disease, amyotrophic lateral sclerosis and stroke), cardiovascular disorders (e.g. atherosclerosis and restenosis), glomerulonephritis, viral infections (e.g. HCMV, HIV and HSV) and parasitic protozoa (Plasmodium sp. and Leishmania sp.).

Lechtzin, N., J. Rothstein, et al. (2002). "Amyotrophic lateral sclerosis: evaluation and treatment of respiratory impairment." Amyotroph Lateral Scler Other Motor Neuron Disord 3(1): 5-13.

            Patients with amyotrophic lateral sclerosis (ALS) invariably develop respiratory muscle weakness and most die from pulmonary complications. There are numerous tests available to evaluate respiratory status in ALS and it is important to understand their various advantages and limitations. Forced vital capacity (FVC) is commonly used but can remain normal despite substantial inspiratory muscle weakness. Maximal pressures measured at the mouth are useful for excluding weakness if they are normal but are difficult to interpret if abnormal. Invasive testing, such as measurement of transdiaphragmatic pressure, provides an accurate measure of inspiratory strength but is not readily available and is not practical for serial measures. There are supportive respiratory techniques that have been shown to benefit patients with ALS. Clinicians should be familiar with these interventions, including mechanically assisted coughing, non-invasive ventilation and tracheostomy with mechanical ventilation. Observational studies have demonstrated improved survival and quality of life with noninvasive ventilation. Tracheostomy with long-term mechanical ventilation is not frequently used but can be an important component of care for ALS. This review describes an approach to respiratory evaluation and care of patients with ALS.

Lindal, S. (2002). "Mitochondria and neurodegenerative diseases--is there a link? The role of mitochondria in the pathogenesis of amyotrophic lateral sclerosis (ALS)." Ultrastruct Pathol 26(1): 1-2.

Liu, B., H. M. Gao, et al. (2002). "Role of nitric oxide in inflammation-mediated neurodegeneration." Ann N Y Acad Sci 962: 318-31.

            Increasing evidence has suggested that inflammation in the brain is closely associated with the pathogenesis of several degenerative neurologic disorders, including Parkinson's disease, Alzheimer's diseases, multiple sclerosis, amyotrophic lateral sclerosis, and AIDS dementia. The hallmark of brain inflammation is the activation of glial cells, especially that of microglia that produce a variety of proinflammatory and neurotoxic factors, including cytokines, fatty acid metabolites, free radicals--such as nitric oxide (NO) and superoxide. Excessive production of NO, as a consequence of nitric oxide synthase induction in activated glia, has been attributed to participate in neurodegeneration. Using primary mixed neuron-glia cultures and glia-enriched cultures prepared from embryonic rodent brain tissues, we have systemically studied the relationship between the production of NO and neurodegeneration in response to stimulation by the inflammagen lipopolysaccharide. This review summarizes our recent findings on the kinetics of NO generation, the relative contribution of microglia and astrocytes to NO accumulation, the relationship between NO production and neurodegeneration, and points of intervention along the pathways associated with NO generation to achieve neuroprotection. We also describe our results relating to the effect of several opioid-related agents on microglial activation and neuroprotection. Among these agents, the opioid receptor antagonist naloxone, especially its non-opioid enantiomer (+)-naloxone, promises to be of potential therapeutic value for the treatment of inflammation-related diseases.

Llanos, R. M. and J. F. Mercer (2002). "The molecular basis of copper homeostasis copper-related disorders." DNA Cell Biol 21(4): 259-70.

            Copper is an essential trace element that can be extremely toxic in excess due to the pro-oxidant activity of copper ions. Inherited disorders of copper transport, Menkes disease (copper deficiency), and Wilson disease (copper toxicosis) are caused by mutations of two closely related Cu transporting-ATPases, and demonstrate the essentiality and potential toxicity of copper. Other copper toxicosis conditions in humans and animals have been described, but are not well understood at a molecular level. Copper homeostatic mechanisms are being discovered. One such mechanism is copper-induced trafficking of the Cu-ATPases, which allows cells to provide copper to secreted cupro-proteins but also to efflux excess copper. Oxidative damage induced by copper may be involved in the pathogenesis of neurodegenerative conditions such as Alzheimer's disease, familial amyotrophic lateral sclerosis, and prion diseases.

Lopez, M. F. and S. Melov (2002). "Applied proteomics: mitochondrial proteins and effect on function." Circ Res 90(4): 380-9.

            The identification of a majority of the polypeptides in mitochondria would be invaluable because they play crucial and diverse roles in many cellular processes and diseases. The endogenous production of reactive oxygen species (ROS) is a major limiter of life as illustrated by studies in which the transgenic overexpression in invertebrates of catalytic antioxidant enzymes results in increased lifespans. Mitochondria have received considerable attention as a principal source---and target---of ROS. Mitochondrial oxidative stress has been implicated in heart disease including myocardial preconditioning, ischemia/reperfusion, and other pathologies. In addition, oxidative stress in the mitochondria is associated with the pathogenesis of Alzheimer's disease, Parkinson's disease, prion diseases, and amyotrophic lateral sclerosis (ALS) as well as aging itself. The rapidly emerging field of proteomics can provide powerful strategies for the characterization of mitochondrial proteins. Current approaches to mitochondrial proteomics include the creation of detailed catalogues of the protein components in a single sample or the identification of differentially expressed proteins in diseased or physiologically altered samples versus a reference control. It is clear that for any proteomics approach prefractionation of complex protein mixtures is essential to facilitate the identification of low-abundance proteins because the dynamic range of protein abundance within cells has been estimated to be as high as 10(7). The opportunities for identification of proteins directly involved in diseases associated with or caused by mitochondrial dysfunction are compelling. Future efforts will focus on linking genomic array information to actual protein levels in mitochondria.

Maier, C. M. and P. H. Chan (2002). "Role of superoxide dismutases in oxidative damage and neurodegenerative disorders." Neuroscientist 8(4): 323-34.

            In recent years, oxidative stress has been implicated in a variety of degenerative processes, diseases, and syndromes. Some of these include atherosclerosis, myocardial infarction, stroke, and ischemia/reperfusion injury; chronic and acute inflammatory conditions such as wound healing; central nervous system disorders such as forms of familial amyotrophic lateral sclerosis (ALS) and glutathione peroxidase-linked adolescent seizures; Parkinson's disease and Alzheimer's dementia; and a variety of other age-related disorders. Among the various biochemical events associated with these conditions, emerging evidence suggests the formation of superoxide anion and expression/activity of its endogenous scavenger, superoxide dismutase (SOD), as a common denominator. This review summarizes the function of SOD under normal physiological conditions as well as its role in the cellular and molecular mechanisms underlying oxidative tissue damage and neurological abnormalities. Experimental evidence from laboratory animals that either overexpress (transgenics) or are deficient (knockouts) in antioxidant enzyme/protein levels and the genetic SOD mutations observed in some familial cases of ALS are also discussed.

McGeer, P. L. and E. G. McGeer (2002). "Inflammatory processes in amyotrophic lateral sclerosis." Muscle Nerve 26(4): 459-70.

            Neuroinflammation is a characteristic of pathologically affected tissue in several neurodegenerative disorders. These changes can be observed in the brainstem and spinal cord of amyotrophic lateral sclerosis (ALS) cases and in mouse models of the disease. They include an accumulation of large numbers of activated microglia and astrocytes, as well as small numbers of T cells, mostly adhering to postcapillary venules. Accompanying biochemical alterations include the appearance of numerous molecules characteristic of free-radical attack, the occurrence of proteins associated with activation of the complement cascade, and a sharp upregulation of the enzyme cyclooxygenase 2 (COX-2). Anti-inflammatory agents may have a role to play in treating ALS. COX-2 is a particularly attractive target because of its marked increase in ALS spinal cord.

Menzies, F. M., P. G. Ince, et al. (2002). "Mitochondrial involvement in amyotrophic lateral sclerosis." Neurochem Int 40(6): 543-51.

            The causes of motor neuron death in amyotrophic lateral sclerosis (ALS) are so far unknown. The involvement of mitochondria in the disease was initially suggested by ultrastructural studies. More recently these observations have been supported by studies of mitochondrial function in ALS. Alterations in the activity of complexes which make up the mitochondrial electron transport chain have been recorded as well as mutations in the mitochondrial genome. The calcium buffering function of the mitochondria may also be affected in the disease. This review will discuss how mitochondrial dysfunction could be of relevance in ALS and the evidence that an alteration of mitochondrial function is a feature of the disease. The way in which the involvement of mitochondria fits with other aetiological hypotheses for ALS will also be discussed.

Miller, R. G. (2002). "Role of fatigue in limiting physical activities in humans with neuromuscular diseases." Am J Phys Med Rehabil 81(11 Suppl): S99-107.

            New methods of examining both central and peripheral fatigue are now available. A broader understanding of the mechanisms of fatigue in healthy human subjects has begun to emerge. The mechanisms of fatigue in patients with various neuromuscular diseases are even more complex than in healthy persons. Examples of both central and peripheral fatigue in various neuromuscular diseases and other disorders are presented, including metabolic myopathy, chronic fatigue syndrome, postpolio syndrome, and amyotrophic lateral sclerosis.

Miller, R. G., J. D. Mitchell, et al. (2002). "Riluzole for amyotrophic lateral sclerosis (ALS)/motor neuron disease (MND)." Cochrane Database Syst Rev(2): CD001447.

            BACKGROUND: Riluzole has been approved for treatment of patients with amyotrophic lateral sclerosis in many countries but not all. Questions persist about its clinical utility because of high cost, modest efficacy and concern over adverse effects. OBJECTIVES: To examine the efficacy of riluzole in prolonging survival, and in delaying the use of surrogates (tracheostomy and mechanical ventilation) to sustain survival. SEARCH STRATEGY: Search of the Cochrane Neuromuscular Disease Group Register for randomized trials and enquiry from authors of trials, Aventis (manufacturer of riluzole) and other experts in the field. The most recent search was May, 2001 SELECTION CRITERIA: Types of studies: randomized trials Types of participants: adults with a diagnosis of amyotrophic lateral sclerosis Types of interventions: treatment with riluzole or placebo Types of outcome measures: Primary: pooled hazard ratio of tracheostomy-free survival over all time points with riluzole 100 mg. Secondary: per cent mortality as a function of time with riluzole 100 mg and other doses of riluzole; neurologic function, quality of life, muscle strength and adverse events. DATA COLLECTION AND ANALYSIS: We identified four eligible randomized trials. Each reviewer graded them for methodological quality. Data extraction was performed by a single reviewer and checked by two others. We obtained some missing data from investigators and regulatory agencies. We performed meta-analyses with Review Manager 4.1 software using a fixed effects model. A test of drug efficacy was based on the Parmar pooled hazard ratio. MAIN RESULTS: The three trials examining tracheostomy-free survival included a total of 876 riluzole treated patients and 406 placebo treated patients. The data for tracheostomy-free survival was not available from the fourth trial. The methodological quality was acceptable and the three trials were easily comparable, although one trial included older patients in more advanced stages of amyotrophic lateral sclerosis. Riluzole 100 mg per day provided a benefit for the homogeneous group of patients in the first two trials (p=0.039, hazard ratio 0.80, 95% confidence interval 0.64 to 0.99) and there was no evidence of heterogeneity (p=0.33). When the third trial (which included older and more seriously affected patients) is added, there is evidence of heterogeneity (p<0.0001) and the random effects model, which takes this into account results in the overall treatment effect estimate falling just short of significance (p=0.056, hazard ratio 0.84, 95% confidence interval 0.70 to 1.01). This represents a 9% gain in the probability of surviving one year (57% in the placebo and 66% in the riluzole group). In secondary analyses of survival at separate time points, there was a significant survival advantage with riluzole 100 mg at six, nine, 12 and 15 months, but not at three or 18 months. There was a small beneficial effect on both bulbar and limb function, but not on muscle strength. There were no data on quality of life, but patients treated with riluzole remained in a more moderately affected health state significantly longer than placebo-treated patients (weighted mean difference 35.5 days, 95% confidence interval 5.9 to 65.0). A threefold increase in serum alanine transferase was more frequent in riluzole treated patients than controls (weighted mean difference 2.69, 95% confidence interval 1.65 to 4.38). REVIEWER'S CONCLUSIONS: Riluzole 100 mg daily is reasonably safe and probably prolongs survival by about two months in patients with amyotrophic lateral sclerosis. More studies are needed, especially to clarify its effect in older patients (over 75 years), and those with more advanced disease.

Mitchell, J. D., J. H. Wokke, et al. (2002). "Recombinant human insulin-like growth factor I (rhIGF-I) for amyotrophic lateral sclerosis/motor neuron disease." Cochrane Database Syst Rev(3): CD002064.

            BACKGROUND: Trophic factors, including recombinant human insulin-like growth factor I have been postulated as possible disease modifying therapies for amyotrophic lateral sclerosis. Randomised clinical trials of recombinant human insulin-like growth factor I in amyotrophic lateral sclerosis to date have yielded conflicting results. OBJECTIVES: The main objective of this review was to examine the efficacy of recombinant human insulin-like growth factor I in amyotrophic lateral sclerosis. Occurrence of adverse events has also been reviewed. SEARCH STRATEGY: A search was carried out using the Cochrane Neuromuscular Disease Group register for randomised clinical trials of recombinant human insulin-like growth factor I in amyotrophic lateral sclerosis. Enquiries were also made of authors of randomised clinical trials as well as the manufacturers of recombinant human insulin-like growth factor I regarding any other randomised clinical trials which had not yet been published. SELECTION CRITERIA: Types of studies: all randomised controlled clinical trials involving recombinant human insulin-like growth factor I treatment of amyotrophic lateral sclerosis. Types of participants: Adults with a clinical diagnosis of definite or probable amyotrophic lateral sclerosis according to the El Escorial Criteria. Types of interventions: Treatment with recombinant human insulin-like growth factor I or placebo. Types of outcome measures: Primary: Change in Appel Amyotrophic Lateral Sclerosis Rating Scale (AALSRS) total score with 0.1mg/kg/day of recombinant human insulin-like growth factor I after nine months treatment. Secondary: Change in AALSRS with recombinant human insulin like growth factor I 0.1mg/kg/day and 0.05mg/kg/day at 1, 2, 3, 4, 5, 6, 7, 8, 9 months, change in quality of life (Sickness Impact Profile scale), survival and adverse events. DATA COLLECTION AND ANALYSIS: We identified two randomised clinical trials. Each reviewer graded them for methodological quality. Data were extracted and entered by the lead reviewer and checked by the other two. Some missing data had to be regenerated by calculations based on ruler measurements of data presented in published graphs. MAIN RESULTS: The primary outcome measure was change in disease progression as determined by the Appel ALS Rating Scale total score with 0.1 mg/kg/day of recombinant human insulin-like growth factor I subcutaneously after nine months treatment. The level of significance was lower in the European trial which compared 59 patients on placebo with 124 on insulin-like growth factor I 0.1 mg/kg/day (weighted mean difference -3.30, 95%CI -8.68 to 2.08) than in the North American trial which compared 90 patients on placebo with 89 on recombinant human insulin-like growth factor I 0.05 mg/kg/day 89 patients and 87 patients on 0.1mg/kg/day (weighted mean difference -6.00, 95%CI -10.99 to -1.01). The combined analysis from both randomised clinical trials showed a weighted mean difference of -4.75 (95% CI -8.41 to -1.09) favouring the treated group. The secondary outcome measures showed similar trends favouring recombinant human insulin-like growth factor I but these did not reach significance at the five per cent level. Similarly the data with the 0.05mg/kg/day dose showed trends favouring recombinant human insulin-like growth factor I at all time points but did not reach significance at the five per cent level at any point. Evaluation of adverse events showed an increased risk of injection site reactions/inflammation with recombinant human insulin-like growth factor I (relative risk 2.53, 95% CI 1.40 to 4.59). The drug was otherwise safe and well tolerated. REVIEWER'S CONCLUSIONS: Recombinant human insulin-like growth factor I may be modestly effective but the evidence currently available is insufficient for a definitive assessment. Further randomised clinical trials need to be done.

Morrison, K. E. (2002). "Therapies in amyotrophic lateral sclerosis-beyond riluzole." Curr Opin Pharmacol 2(3): 302-9.

            Several mechanisms have been proposed to account for the progressive motor neurone death evident in amyotrophic lateral sclerosis. These include oxidative stress, neurofilament damage, mitochondrial abnormalities, glutamate-mediated excitotoxicity and altered responses to hypoxia. Current quests for therapies involve studying combinations of agents that act by various mechanisms and evaluating stem-cell therapies in model systems. High-throughput cell-culture screening systems are also being developed. The goal for therapy is to define agents that clearly prevent progression of, and it is hoped even reverse, motor neurone loss.

Murray, B. and H. Mitsumoto (2002). "Drug therapy in amyotrophic lateral sclerosis." Adv Neurol 88: 63-82.

Newbery, H. J. and C. M. Abbott (2002). "Of mice, men and motor neurons." Trends Mol Med 8(2): 88-92.

            The use of mouse models has been of particular importance in studying the pathogenesis of amyotrophic lateral sclerosis. Here, we describe both transgenic and classical mutants for which the genetic lesion is known. We draw attention, wherever possible, to pathological factors common to multiple models.

Nguimfack Mbodie, P. C. (2002). "[Do the glutamate excitotoxicity theory and potential free radicals implication in schizophrenia aetiopathogenesis provide a new enlightenment to links between: genome, environment and biology in the determinism of that disorder?]." Encephale 28(2): 147-53.

            The aetiopathogenesis of schizophrenia constitutes nowadays one of the major points of interest for researchers on this cosmopolitan disorder which involves about 1% of the world population and which significantly alters the social functioning of the individual. Numerous studies have focused on the role played by genome, environmental factors and biology in the development of symptoms. The neurodevelopmental theory is an illustration with the perinatal period considered as the main provider of environmental factors (hypertension, infections, bleedings during pregnancy, acute and chronic fetal distress.). Many authors found significant associations between such factors, the occurrence of brain lesions and finally schizophrenic symptoms. Although no convincing genetic model had been established to date for schizophrenia, nevertheless it appears that a predisposition not inheritable under the mendelian mode exists and authors showed that disease gets more and more severe over schizophrenic descendants. The risk to be schizophrenic being a first degree relative of the schizophrenic person is about ten time superior than in general population. Indeed, this risk is also about ten time superior in biological parents of schizophrenic adoptees than in biological parents of healthy adoptees. Studies done in monozygotic comparing to dizygotic twins are in favour of an important role played by genetic factors more than socioeducational or psychological factors. Concerning biology, the dopaminergic hypothesis remains shared by numerous authors although direct links with incriminated factors are not well established. Now is suspected the glutamate excitotoxicity with implication of free radicals in schizophrenia. These free radicals are products of various enzymatic activations led by overstimulation of post synaptic receptors (NMDA and AMPA) by the excess glutamate. Therefore, according to that concept, some amino acids as glutamate and derivatives could have through free radicals a noxious effect on neuronal synapses. This could be due to a failing of their recapture at the presynaptic level in addition to a dysfunctioning of the antioxidizing system (glutathion, carnosine, superoxide dismutase, aspartate) to which dopamine and other monoamines might participate. The question is whether or not this theory contributes to shed light on links between: genome, environmental factors and biology in schizophrenia. Through the review and discussion of genetical aspects of schizophrenia, environmental factors and the biological aspect, we intend to revive debate on that question. The articles and authors were selected with regard to the aptness of their publications on that subject, their evolving ideas and finally the interest of their works for neurosciences. This new approach perhaps is opening the way to new therapeutic perspectives in the treatment of schizophrenia based on the antioxidizing substances as shown for some neurological diseases (amyotrophic lateral sclerosis, Parkinson's disease and Huntington's chorea) for which experiments are going on.

Patzke, H. and L. H. Tsai (2002). "Cdk5 sinks into ALS." Trends Neurosci 25(1): 8-10.

            Recent research points to an involvement of deregulated cdk5 activity in the pathogenesis of mutant SOD1-mediated disease. In addition, inhibition of this activity might promote motor neuron survival. These observations have opened the door to further research into the role of cdk5 in ALS and other neurodegenerative diseases.

Perry, G., L. M. Sayre, et al. (2002). "The role of iron and copper in the aetiology of neurodegenerative disorders: therapeutic implications." CNS Drugs 16(5): 339-52.

            Abnormalities in the metabolism of the transition metals iron and copper have been demonstrated to play a crucial role in the pathogenesis of various neurodegenerative diseases. Metal homeostasis as it pertains to alterations in brain function in neurodegenerative diseases is reviewed in this article in depth. While there is documented evidence for alterations in the homeostasis, redox-activity and localisation of transition metals, it is also important to realise that alterations in specific copper- and iron-containing metalloenzymes appear to play a crucial role in the neurodegenerative process. These changes provide the opportunity to identify pathways where modification of the disease process can occur, potentially offering opportunities for clinical intervention. As understanding of disease aetiology evolves, so do the tools with which diseases are treated. In this article, we examine not only the possible mechanism of disease but also how pharmaceuticals may intervene, from direct and indirect antioxidant therapy to strategies involving gene therapy.

Portegies, P. and E. S. Cohen (2002). "[Possible etiological role retroviruses and enteroviruses in the development of amyotrophic lateral sclerosis]." Ned Tijdschr Geneeskd 146(30): 1398-400.

            Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with unknown pathogenesis. Loss of motor neurons leads to progressive weakness and, finally, respiratory failure with a mean survival of 3 years. A possible causal role of a retroviral infection has recently been suggested by studies of 7 HIV-infected patients who developed a rapid progressive ALS-like disorder as the first manifestation of their HIV-infection. All patients stabilised or improved with antiretroviral therapy. Other research groups have published on the detection of enterovirus RNA in the spinal cords of ALS-patients, also suggesting a viral aetiology of the disease. The results of these neuro-virological studies warrant further research into the possible role of viral infections as a cause of ALS, as well as clinical trials with anti-retroviral and anti-enteroviral drugs in ALS.

Poulsen, D. J., J. S. Harrop, et al. (2002). "Gene therapy for spinal cord injury and disease." J Spinal Cord Med 25(1): 2-9.

            An incomplete understanding of the pathological processes involved in neurodegeneration and dysfunction of spinal cord injuries and diseases makes these disorders difficult to treat. Repair of damaged or genetically impaired spinal cord also has been limited by the complexity, cellular heterogeneity, and relative inaccessibility of the tissue. Thus, therapeutic options for the treatment of either chronic spinal cord diseases such as amyotrophic lateral sclerosis or acute spinal cord injuries have been rather limited. Potential new therapeutic targets are being identified as our understanding of the molecular pathology involved in neural injury and regeneration increases. Recent advances in gene transfer techniques have made gene therapy a more realistic and viable strategy for the treatment of a broad range of spinal cord disorders. This review summarizes the current state of knowledge regarding the limitations and recent advances in gene therapy and potential application of this technology toward spinal cord injury and disease.

Reimers, C. D. and H. Kele (2002). "[Muscle ultrasound in neuromuscular diseases]." Orthopade 31(2): 165-71.

            Imaging modalities are the only noninvasive methods that provide morphological information on skeletal muscles. In neuromuscular diseases, electrodiagnostic investigations are routinely employed in the diagnostic process, although they only deliver functional information. Thus, imaging and electro-diagnostic methods are not in competition, but complement each other. Each method has its specific indications. The technique and diagnostic value of muscle ultrasound in neuromuscular diseases are presented in this review.

Rosso, S. M. and J. C. van Swieten (2002). "New developments in frontotemporal dementia and parkinsonism linked to chromosome 17." Curr Opin Neurol 15(4): 423-8.

            PURPOSE OF REVIEW: The identification of tau mutations in frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) has revealed invaluable information regarding the role of the tau protein in neurodegenerative disease. Over the past year several new mutations have been identified, and experimental studies have provided further insight into the mechanism of neurodegeneration due to tau mutations and possible interactions with amyloid pathology. RECENT FINDINGS: Extensive clinical and pathological variation is seen in patients with different types of mutation, as well as in patients with the same mutation. Mutations may be found in patients with frontotemporal dementia (FTD), parkinsonism, progressive supranuclear palsy and corticobasal degeneration, justifying mutation analysis in familial cases of these disorders. Genetic heterogeneity exists in frontotemporal dementia, because a number of FTDP-17 families have neither tau mutations nor tau pathology. Genetic linkage has been found in familial FTD (chromosome 3), FTD with amyotrophic lateral sclerosis (9q21-q22), and FTD with inclusion body myopathy (9q13.3-p12). Tau deposits may consist of mainly mutated protein, or of mutated and wild-type protein in equal amounts, depending on the mutation. Recent animal studies show that amyloid-beta deposition may accelerate formation of neurofibrillary tangles. SUMMARY: Hopefully, the identification of responsible genetic defects and associated proteins will be helpful in improving our understanding of the role of the tau protein in the common neurodegenerative process of frontotemporal degeneration.

Schapira, A. H. (2002). "Primary and secondary defects of the mitochondrial respiratory chain." J Inherit Metab Dis 25(3): 207-14.

            Over 100 mutations of mitochondrial DNA (mtDNA) have been associated with human disease. The phenotypic manifestation of mtDNA mutations is extremely broad, from oligosymptomatic patients with isolated deafness, diabetes, ophthalmoplegia, etc., to complex encephalomyopathic disorders that may include dementia, seizures, ataxia, stroke-like episodes, etc. The genotype variants are also wide, with rearrangements (deletions, duplications) and point mutations affecting protein coding genes, tRNAs and rRNAs. There are some broad genotype/phenotype correlations but also substantial overlap. The pathogenetic mechanisms involved in the expression of mtDNA mutations are still not yet fully understood. More recently, mutations of nuclear genes encoding subunits of the respiratory chain, particularly those of complex I, have been identified. These predominantly, but not exclusively, involve infant onset disease with early death. Recently it has become clear that the function of the respiratory chain may be impaired by mutations affecting other mitochondrial proteins or as a secondary phenomenon to other intracellular biochemical derangements. Examples include Friedreich ataxia where a mutation of a nuclear encoded protein (frataxin), probably involved in iron homeostasis in mitochondria, results in severe deficiency of the respiratory chain in a pattern indicative of free radical mediated damage. Mutations of nuclear encoded proteins involved in cytochrome oxidase assembly and maintenance have been characterised and, as predicted, are associated with severe deficiency of cytochrome oxidase and, most frequently, Leigh syndrome. Defects of intracellular metabolism, with particularly excess-free radical generation including nitric oxide or peroxynitrite, may cause secondary damage to the respiratory chain. This is probably of relevance in Huntington disease, motor neuron disease (amyotrophic lateral sclerosis) and Wilson disease. These disorders seem to have defective oxidative phosphorylation as a common pathway in their pathogenesis and it may be that treatments designed to improve respiratory chain function may ameliorate the progression of these disorders.

Schindler, J. S. and J. H. Kelly (2002). "Swallowing disorders in the elderly." Laryngoscope 112(4): 589-602.

            Changes that occur as a natural part of senescence in the complex action of deglutition predispose us to dysphagia and aspiration. As the "baby-boomers" begin to age, the onset of swallowing difficulties will begin to manifest in a greater number of our population. Recent advances in the evaluation of normal and abnormal swallowing make possible more precise anatomical and physiological diagnoses. Coupled with an understanding of swallowing physiology, such detailed evaluation allows greater opportunity to safely manage dysphagia with directed therapy and appropriate surgical intervention. The current study is a discussion of the changes that occur in deglutition with normal aging, contemporary evaluation of swallowing function, and some of the common causes of dysphagia in elderly patients.

Shimizu, A., T. Nakanishi, et al. (2002). "Detection and identification of protein variants and adducts in blood and tissues: an application of soft ionization mass spectrometry to clinical diagnosis." J Chromatogr B Analyt Technol Biomed Life Sci 776(1): 15-30.

            The detection and identification of protein variants and abnormally increased modified proteins are important for clinical diagnosis. We applied soft ionization mass spectrometry (MS) to analyze proteins in blood and tissues from various patients. Over the past 8 years, we diagnosed 132 cases (55 kinds) of variant proteins including hemoglobin (Hb), transthyretin (TTR), and Cu/Zn-superoxide dismutase (SOD-1), using MS as the leading technology. Of these variants, eight were new, and nine were the first cases in Japan. Some abnormal Hb cause diseases, and most of them cause erroneous levels of glycated Hb, HbA1c, i.e., a popular index of diabetes. Most of the variant TTR causes amyloidotic polyneuropathy. Variant SOD-1 causes amyotrophic lateral sclerosis. We first showed that immunoprecipitation by a specific antiserum is a reliable and simple method to prepare protein from sera and tissues for analysis by matrix-assisted laser desorption time-of-flight MS, and liquid chromatography-electrospray ionization MS (LC-ESI-MS). The use of this technology has become widespread. Using an immunoprecipitated target protein and LC-ESI-MS, we showed that the ratios of tetra-, di- and a-sialo-transferrin from two cases of congenital glycoprotein deficient syndrome were clearly distinguishable from those of control samples. We first reported a unique modified form of TTR, that is, S-sulfonated TTR, which increased markedly and specifically in three cases with molibdenum cofactor deficiency. We proposed that S-sulfonated TTR is a useful marker for screening this disease. ESI-MS was successfully used for the accurate determination of HbA1c, and we clarified the extent of discrepancies between the HbA1c value measured by conventional methods and the accurate values for samples containing various Hb variants determined by the MS method.

Shneerson, J. M. and A. K. Simonds (2002). "Noninvasive ventilation for chest wall and neuromuscular disorders." Eur Respir J 20(2): 480-7.

            Neuromuscular and chest wall disorders are individually uncommon but together form an important group of conditions that can lead to chronic ventilatory failure. This is best recognised in scoliosis, kyphosis, following a thoracoplasty, in muscular dystrophies, such as Duchenne muscular dystrophy (DMD), and myotonic dystrophy, after poliomyelitis and with motor neurone disease (amyotrophic lateral sclerosis). If bulbar function is impaired, tracheostomy ventilation may be required, but in other situations, noninvasive ventilation is preferable. Positive pressure techniques using nasal and face masks are usually the first choice, but negative pressure ventilation is an alternative. There are no randomised-controlled trials regarding the indications for initiating noninvasive ventilation, but this is usually provided if there are symptoms due to nocturnal hypoventilation or right heart failure in the presence of a raised carbon dioxide tension in arterial blood (Pa,CO2) either at night or, more usually, in the daytime as well. There is no evidence that "prophylactic" ventilatory support is of benefit if this is provided before ventilatory failure has appeared. Careful selection of patients is required, especially in the presence of progressive neuromuscular disorders such as DMD and motor neurone disease. There are no randomised-controlled trials concerning the outcome of noninvasive ventilation in these conditions, but studies have shown an improved quality of life, physical activity and haemodynamics, normalisation of blood gases and slight improvement in other physiological measures, such as the vital capacity and maximal mouth pressures. Survival in chest wall disorders is approximately 90% at 1 yr and 80% at 5 yrs, and similar figures have been obtained in nonprogressive neuromuscular conditions. If, however, the underlying disorder is deteriorating, particularly if it involves the bulbar muscles, it may limit survival despite the provision of adequate noninvasive ventilatory support.

Siddique, T. and I. Lalani (2002). "Genetic aspects of amyotrophic lateral sclerosis." Adv Neurol 88: 21-32.

Simpson, E. P., D. Mosier, et al. (2002). "Mechanisms of disease pathogenesis in amyotrophic lateral sclerosis. A central role for calcium." Adv Neurol 88: 1-19.

Smith, D. S. and L. H. Tsai (2002). "Cdk5 behind the wheel: a role in trafficking and transport?" Trends Cell Biol 12(1): 28-36.

            Cdk5, a serine/threonine kinase in the cyclin-dependent kinase (Cdk) family, is an important regulator of neuronal positioning during brain development. Cdk5 might also play a role in synaptogenesis and neurotransmission. Loss of Cdk5 in mice is perinatal lethal, and overactive Cdk5 induces apoptosis in cultured cells, indicating that strict regulation of kinase activity is crucial. Indeed, activity depends on the stability of activating partners, subcellular localization and the phosphorylation state of the enzyme itself. Deregulated kinase activity has been linked to neurodegenerative diseases such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS). This review focuses on links between Cdk5 activity and components of cytoskeletal, membrane and adhesion systems that allow us to postulate a role for Cdk5 in directing intracellular traffic in neurons.

Smyth, P. G. and S. A. Berman (2002). "Markers of apoptosis: methods for elucidating the mechanism of apoptotic cell death from the nervous system." Biotechniques 32(3): 648-50, 652, 654 passim.

            Apoptosis is a highly conserved energy-requiring program for non-inflammatory cell death that is important in both normal physiology and disease. Numerous techniques have been used to study apoptosis. In the nervous system, apoptosis is necessary for normal development, but it also occurs in many acute and chronic pathologic conditions. This review places commonly used markers of apoptosis and their detection in the context of what is now known about the process of apoptosis. We review the potential role of apoptosis in nervous system and neurodegenerative disorders (Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis). We then describe important morphological, immunocytochemical, and molecular genetic markers for apoptosis, including proteases, signal transduction molecules, and mitochondrial proteins. The possibility of manipulating apoptosis therapeutically in conditions of too many or too few cells is under active investigation.

Talbot, K. (2002). "Motor neurone disease." Postgrad Med J 78(923): 513-9.

            Motor neurone disease (MND), or amyotrophic lateral sclerosis (ALS), is a neurodegenerative disorder of unknown aetiology. Progressive motor weakness and bulbar dysfunction lead to premature death, usually from respiratory failure. Confirming the diagnosis may initially be difficult until the full clinical features are manifest. For all forms of the disease there is a significant differential diagnosis to consider, including treatable conditions, and therefore specialist neurological opinion should always be sought. Clear genetic inheritance has been demonstrated in a minority of patients with familial ALS but elucidation of the biological basis of genetic subtypes is also providing important information which may lead to treatments for sporadic forms of the disease. In the absence of curative or disease modifying therapy, management is supportive and requires a multidisciplinary approach. If, as seems likely, complex inherited and environmental factors contribute to the pathogenesis of MND, future treatment may involve a combination of molecular based treatments or restoration of cellular integrity using stem cell grafts.

Taylor, J. P., J. Hardy, et al. (2002). "Toxic proteins in neurodegenerative disease." Science 296(5575): 1991-5.

            A broad range of neurodegenerative disorders is characterized by neuronal damage that may be caused by toxic, aggregation-prone proteins. As genes are identified for these disorders and cell culture and animal models are developed, it has become clear that a major effect of mutations in these genes is the abnormal processing and accumulation of misfolded protein in neuronal inclusions and plaques. Increased understanding of the cellular mechanisms for disposal of abnormal proteins and of the effects of toxic protein accumulation on neuronal survival may allow the development of rational, effective treatment for these disorders.

Trojanowski, J. Q., T. Ishihara, et al. (2002). "Amyotrophic lateral sclerosis/parkinsonism dementia complex: transgenic mice provide insights into mechanisms underlying a common tauopathy in an ethnic minority on Guam." Exp Neurol 176(1): 1-11.

            Intracytoplasmic filamentous tau inclusions are neuropathological hallmarks of amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) of Guam and the defining lesions of other neurodegenerative disorders known as tauopathies. Here we review current insights into the cell and molecular neuropathology of ALS/PDC, a common tauopathy in the Chamorro population on Guam. We also summarize recent advances in understanding this disorder through studies of transgenic (Tg) mouse models of this tauopathy. Briefly, overexpression of human tau isoforms in the central nervous system of Tg mice resulted in a neurodegenerative tauopathy with a phenotype similar to ALS/PDC. Specifically, argyrophilic, congophilic, and tau immunoreactive inclusions accumulated with age in cortical and brainstem neurons of these mice, but they were most abundant in spinal cord neurons, and the inclusions contained 10- to 20-nm tau-positive straight filaments. There also was extensive gliosis in spinal cord associated with axonal degeneration in the ventral roots, while remaining axons in spinal nerves showed a loss of microtubules and reduced fast axonal transport. With advancing age, these Tg mice showed increasing motor weakness, and this was accompanied by a progressive increase in the phosphorylation and insolubility of brain and spinal cord tau proteins. Thus, tau Tg mice recapitulate key phenotypic features of ALS/PDC neuropathology in an ethnic minority on Guam, and these animal models provide new opportunities to discover novel therapies for this and related tauopathies.

Wolpaw, J. R., N. Birbaumer, et al. (2002). "Brain-computer interfaces for communication and control." Clin Neurophysiol 113(6): 767-91.

            For many years people have speculated that electroencephalographic activity or other electrophysiological measures of brain function might provide a new non-muscular channel for sending messages and commands to the external world - a brain-computer interface (BCI). Over the past 15 years, productive BCI research programs have arisen. Encouraged by new understanding of brain function, by the advent of powerful low-cost computer equipment, and by growing recognition of the needs and potentials of people with disabilities, these programs concentrate on developing new augmentative communication and control technology for those with severe neuromuscular disorders, such as amyotrophic lateral sclerosis, brainstem stroke, and spinal cord injury. The immediate goal is to provide these users, who may be completely paralyzed, or 'locked in', with basic communication capabilities so that they can express their wishes to caregivers or even operate word processing programs or neuroprostheses. Present-day BCIs determine the intent of the user from a variety of different electrophysiological signals. These signals include slow cortical potentials, P300 potentials, and mu or beta rhythms recorded from the scalp, and cortical neuronal activity recorded by implanted electrodes. They are translated in real-time into commands that operate a computer display or other device. Successful operation requires that the user encode commands in these signals and that the BCI derive the commands from the signals. Thus, the user and the BCI system need to adapt to each other both initially and continually so as to ensure stable performance. Current BCIs have maximum information transfer rates up to 10-25bits/min. This limited capacity can be valuable for people whose severe disabilities prevent them from using conventional augmentative communication methods. At the same time, many possible applications of BCI technology, such as neuroprosthesis control, may require higher information transfer rates. Future progress will depend on: recognition that BCI research and development is an interdisciplinary problem, involving neurobiology, psychology, engineering, mathematics, and computer science; identification of those signals, whether evoked potentials, spontaneous rhythms, or neuronal firing rates, that users are best able to control independent of activity in conventional motor output pathways; development of training methods for helping users to gain and maintain that control; delineation of the best algorithms for translating these signals into device commands; attention to the identification and elimination of artifacts such as electromyographic and electro-oculographic activity; adoption of precise and objective procedures for evaluating BCI performance; recognition of the need for long-term as well as short-term assessment of BCI performance; identification of appropriate BCI applications and appropriate matching of applications and users; and attention to factors that affect user acceptance of augmentative technology, including ease of use, cosmesis, and provision of those communication and control capacities that are most important to the user. Development of BCI technology will also benefit from greater emphasis on peer-reviewed research publications and avoidance of the hyperbolic and often misleading media attention that tends to generate unrealistic expectations in the public and skepticism in other researchers. With adequate recognition and effective engagement of all these issues, BCI systems could eventually provide an important new communication and control option for those with motor disabilities and might also give those without disabilities a supplementary control channel or a control channel useful in special circumstances.

Wong, P. C., H. Cai, et al. (2002). "Genetically engineered mouse models of neurodegenerative diseases." Nat Neurosci 5(7): 633-9.

            Recent research has significantly advanced our understanding of the molecular mechanisms of neurodegenerative diseases, including Alzheimer's disease (AD) and motor neuron disease. Here we emphasize the use of genetically engineered mouse models that are instrumental for understanding why AD is a neuronal disease, and for validating attractive therapeutic targets. In motor neuron diseases, Cu/Zn superoxide dismutase and survival motor neuron mouse models are useful in testing disease mechanisms and therapeutic strategies for amyotrophic lateral sclerosis (ALS) and spinal motor atrophy, respectively, but the mechanisms that account for selective motor neuron loss remain uncertain. We anticipate that, in the future, therapies based on understanding disease mechanisms will be identified and tested in mouse model systems.

Wyss, M. and A. Schulze (2002). "Health implications of creatine: can oral creatine supplementation protect against neurological and atherosclerotic disease?" Neuroscience 112(2): 243-60.

            Major achievements made over the last several years have highlighted the important roles of creatine and the creatine kinase reaction in health and disease. Inborn errors of metabolism have been identified in the three main steps involved in creatine metabolism: arginine:glycine amidinotransferase (AGAT), S-adenosyl-L-methionine:N-guanidinoacetate methyltransferase (GAMT), and the creatine transporter. All these diseases are characterized by a lack of creatine and phosphorylcreatine in the brain, and by (severe) mental retardation. Similarly, knockout mice lacking the brain cytosolic and mitochondrial isoenzymes of creatine kinase displayed a slightly increased creatine concentration, but no phosphorylcreatine in the brain. These mice revealed decreased weight gain and reduced life expectancy, disturbed fat metabolism, behavioral abnormalities and impaired learning capacity.Oral creatine supplementation improved the clinical symptoms in both AGAT and GAMT deficiency, but not in creatine transporter deficiency. In addition, creatine supplementation displayed neuroprotective effects in several animal models of neurological disease, such as Huntington's disease, Parkinson's disease, or amyotrophic lateral sclerosis. All these findings pinpoint to a close correlation between the functional capacity of the creatine kinase/phosphorylcreatine/creatine system and proper brain function. They also offer a starting-point for novel means of delaying neurodegenerative disease, and/or for strengthening memory function and intellectual capabilities.Finally, creatine biosynthesis has been postulated as a major effector of homocysteine concentration in the plasma, which has been identified as an independent graded risk factor for atherosclerotic disease. By decreasing homocysteine production, oral creatine supplementation may, thus, also lower the risk for developing, e.g., coronary heart disease or cerebrovascular disease.Although compelling, these results require further confirmation in clinical studies in humans, together with a thorough evaluation of the safety of oral creatine supplementation.

Xiong, Z. Q. and J. O. McNamara (2002). "Fas(t) balls and Lou Gehrig disease. A clue to selective vulnerability of motor neurons?" Neuron 35(6): 1011-3.

            The molecular basis of the selective death of motor neurons in amyotrophic lateral sclerosis (ALS) has been an enigma since its description by Charcot in 1869. In this issue of Neuron, demonstrate a motor neuron-specific death pathway which involves Fas and NO. Remarkably, motor neurons from mice carrying ALS-linked mutant forms of superoxide dismutase 1 (SOD1) exhibit an increased sensitivity to death triggered by Fas but not other insults. These data suggest new insights into the mechanisms of, and potential therapeutic strategies for, death of motor neurons in ALS.

Zelko, I. N., T. J. Mariani, et al. (2002). "Superoxide dismutase multigene family: a comparison of the CuZn-SOD (SOD1), Mn-SOD (SOD2), and EC-SOD (SOD3) gene structures, evolution, and expression." Free Radic Biol Med 33(3): 337-49.

            Superoxide dismutases are an ubiquitous family of enzymes that function to efficiently catalyze the dismutation of superoxide anions. Three unique and highly compartmentalized mammalian superoxide dismutases have been biochemically and molecularly characterized to date. SOD1, or CuZn-SOD (EC 1.15.1.1), was the first enzyme to be characterized and is a copper and zinc-containing homodimer that is found almost exclusively in intracellular cytoplasmic spaces. SOD2, or Mn-SOD (EC 1.15.1.1), exists as a tetramer and is initially synthesized containing a leader peptide, which targets this manganese-containing enzyme exclusively to the mitochondrial spaces. SOD3, or EC-SOD (EC 1.15.1.1), is the most recently characterized SOD, exists as a copper and zinc-containing tetramer, and is synthesized containing a signal peptide that directs this enzyme exclusively to extracellular spaces. What role(s) these SODs play in both normal and disease states is only slowly beginning to be understood. A molecular understanding of each of these genes has proven useful toward the deciphering of their biological roles. For example, a variety of single amino acid mutations in SOD1 have been linked to familial amyotrophic lateral sclerosis. Knocking out the SOD2 gene in mice results in a lethal cardiomyopathy. A single amino acid mutation in human SOD3 is associated with 10 to 30-fold increases in serum SOD3 levels. As more information is obtained, further insights will be gained.

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