Characteristics of F-wave in different stretched positions of the affected arm in patients with cerebrovascular diseases.

To investigate the effect of continued stretching of affected arms in patients with cerebrovascular disease (CVD), F-wave was tested from the abductor pollicis brevis (APB) during relaxation (trial 1) and 3 different continued stretches: stretched position with shoulder abduction (trial 2), stretched position with shoulder abduction and elbow extension (trial 3), and stretched position with shoulder abduction, elbow extension and wrist extension (trial 4) of the affected arm for 1 min. in 20 hemiparesis patients with moderate hypertonus (modified Ashworth scale of 2 or 3) caused by CVD (mean age of 49.5 years). Persistence and amplitude ratio of F/M in trial 2 were the same as those in trial 1. Persistence and amplitude ratio of F/M in trials 3 and 4 were significantly lower than those in trial 1. It was suggested that excitability of spinal neural function of the distal part, the APB, of the affected arm was reduced during continued stretching of the proximal part, shoulder and elbow joints, or all of the shoulder, elbow and wrist joints in hemiparesis patients with moderate hypertonus caused by CVD.

Effect of continued stretching of the affected arm in patients with cerebrovascular diseases by examining H-reflex characteristics.

To investigate excitability of spinal neural function during stretching excises in patients with cerebrovascular disease (CVD), H-reflex was analyzed before, during and after 1 min. continued stretching of the affected arm. 10 hemiparesis patients with hypertonus and hyperreflex, mean age of 53.2 years were tested. H-reflex was recorded from the abductor pollicis brevis on the affected side after stimulation of median nerve in supine position. The persistence, amplitude and amplitude ratio of H/M during stretching were lower than those before and after in the patients with moderately increased muscle tonus. In patients with slightly and markedly increased, H-reflex was same before, during and after continued stretching. It is suggested that excitability of spinal neural function during 1 min. continued stretching was inhibited in the patients with moderately increased muscle tonus caused by CVD.

Characteristic appearances of the H-reflex and F-wave with increased stimulus intensity in patients with cerebrovascular disease.

We experienced H-reflex may be evoked with supramaximal stimulation in patients with cerebrovascular disease (CVD). In this study, we investigated the relationship between the characteristic appearances of H-reflex and F-wave with increased stimulus intensity and neurological signs. We examined the H-reflex and F-wave of the affected arm with increased stimulus intensity during muscle relaxation in 31 patients (17 males and 14 females) with hemiparesis caused by CVD. Mean patient age was 56.0 (range 30-82) years. 30 healthy subjects, mean age of 56.2 (range 28-80) were investigated using the same method as controlled group. H-reflex and F-wave with increased stimulus intensity after the median nerve stimulation at the wrist were recorded from the opponence pollicis muscle on the affected side in patients with CVD or right arm in the healthy subjects. Appearance patterns of the H-reflex and F-wave with increased stimulus intensity was separated into four types. Type 1: F-wave appeared with increased stimulus intensity, but there was no H-reflex. Type 2: H-reflex and F-wave both appeared with increased stimulus intensity, but the F-wave followed disappearance of the H-reflex with increased stimulus intensity. Type 3: H-reflex and F-wave both appeared with increased stimulus intensity, but the F-wave appeared during the H-reflex with increased stimulus intensity. Type 4: Only the H-reflex appeared with increased stimulus intensity, but there was no F-wave. Neurological findings including muscle tone and tendon reflex were also evaluated. Findings on muscle tone and tendon reflex were classified into increased (markedly, moderately and slightly), normal and decreased. Results were analyzed as follows; 1) The characteristic appearances of H-reflex and F-wave in the healthy subjects and 2) The relationship between characteristic appearances of waves with increased stimulus intensity and neurological signs in patients with CVD. 1) Pattern of the H-reflex and F-wave with increased stimulus intensity in all healthy subjects were type 1. 2) Patterns of the H-reflex and F-wave with increased stimulus intensity in patients with markedly increased muscle tone and tendon reflex were almost always type 4. Those with moderately increased signs in this parameter demonstrated type 2 or 3. Those with slightly increased signs in this parameter demonstrated type 1 or 2. Those with normal or decreased signs were type 1. These findings suggest that the characteristic appearances of the H-reflex and F-wave was influenced by grade of neurological signs.

Kii ALS dementia.

Epidemiological surveys in the foci of ALS of the Kii Peninsula of Japan started in the early 1960s. Continuous surveys conducted for decades revealed that there have been two foci in the Kii Peninsula: one in Kozagawa in the southern part, and the other in Hobara in the south-east. Clinically, ALS patients of the Kii foci occasionally showed parkinsonian features or dementia that have not been reported in the sporadic form of ALS. Neuropathologically, numerous NFT that are identical to those of Alzheimer's disease were observed in the cerebral cortex and in the brainstem nuclei. To elucidate the etiopathogenesis of this unique form of ALS, an analysis was conducted of the environment in the focus areas and of the specimens from the patients with ALS. It was hypothesized that the long exposure of these environments to low calcium and magnesium, and an excess of aluminum and manganese in the drinking water and the soil, might lead to the deposition of some trace elements in the CNS, eventually causing neuronal degeneration and death.

Advanced glycation end products in Alzheimer's disease and other neurodegenerative diseases.

Advanced glycation end products (AGEs) have been implicated in the chronic complications of diabetes mellitus and have been reported to play an important role in the pathogenesis of Alzheimer's disease. In this study, we examined the immunohistochemical localization of AGEs, amyloid beta protein (A beta), apolipoprotein E (ApoE), and tau protein in senile plaques, neurofibrillary tangles (NFTs), and cerebral amyloid angiopathy (CAA) in Alzheimer's disease and other neurodegenerative diseases (progressive supranuclear palsy, Pick's disease, and Guamanian amyotrophic lateral sclerosis/Parkinsonism-dementia complex). In most senile plaques (including diffuse plaques) and CAA from Alzheimer's brains, AGE and ApoE were observed together. However, approximately 5% of plaques were AGE positive but A beta negative, and the vessels without CAA often showed AGE immunoreactivity. In Alzheimer's disease, AGEs were mainly present in intracellular NFTs, whereas ApoE was mainly present in extracellular NFTs. Pick's bodies in Pick's disease and granulovacuolar degeneration in various neurodegenerative diseases were also AGE positive. In non-Alzheimer neurodegenerative diseases, senile plaques and NFTs showed similar findings to those in Alzheimer's disease. These results suggest that AGE may contribute to eventual neuronal dysfunction and death as an important factor in the progression of various neurodegenerative diseases, including Alzheimer's disease.

Epidemiology of motor neuron disease in the Kii Peninsula of Japan, 1989-1993: active or disappearing focus?

During the period 1989-1993, the incidence and migration patterns of patients with motor neuron diseases (MND) in Wakayama Prefecture, including one of the high-incidence Kii Peninsula foci ('Kozagawa focus'), were surveyed to determine whether the focus had truly disappeared or not. Overall, the crude average annual incidence was 1.43 per 100000 population; when age-adjusted to the 1990 Japanese population, it was 1.25 (1.85 for males and 0.61 for females). The average annual age- and sex-specific incidence steadily increased to a peak between 60 and 69 years and dropped after 70. Geographically, the rates varied in the five regions of Wakayama Prefecture from 0.38 to 2.48. The areas with high incidence were distributed in the central and southernmost regions; the highest was in the Kozagawa focus with 9.54 (two ALS cases within five years; 4193 base population, 1990). During the study period, four emigrants from Kozagawa had developed MND one to four decades after leaving the focus. Although the remarkable clustering of MND was thought to have disappeared, the southern Kii Peninsula remains a high-risk area for MND, especially if one interprets the data so as to include the emigrants. In general, the age at onset has increased in the past 20 years from 56.5 to 61.7; male predominance is observed.

Involvement of Onuf's nucleus in amyotrophic lateral sclerosis.

The Onufrowicz (Onuf's) nuclei from eight amyotrophic lateral sclerosis (ALS) cases and nine neurological control cases were studied histologically and morphometrically. To clarify the factors relating to the involvement of the Onuf's nucleus in ALS, we correlated the relationships among the age at death, clinical duration, morphometric findings for Onuf's neurons, and neuronal numbers in the posteroposterolateral (PPL) nuclei in the ALS cases with those in neurological controls. Intracytoplasmic inclusions such as Bunina bodies, ubiquitin-reactive inclusions, and conglomerate inclusion were found in the Onuf's neurons in ALS, but not in the controls. The total number of Onuf's neurons in the ALS cases was not decreased, but that of normal-appearing neurons was decreased while that of atrophic neurons was increased. Significantly decreased perikaryal, nuclear and nucleolar areas and decreased perikaryal (P)/nuclear and P/nucleolar area ratios of Onuf's neurons were found in ALS, not only in the atrophic neurons but also in the normal-appearing neurons, compared with the controls. The shrinkage in Onuf's neurons of ALS was different from that seen in the ageing process or in the axonal reactions of controls with atonic bladder. In ALS, the morphometric findings for the Onuf's neurons showed no correlation with age at death, clinical duration, or number of PPL neurons. Our results indicate that in ALS Onuf's nucleus is principally vulnerable to the ALS process, although the degree of degeneration differs from that seen in other motor neurons. The involvement of Onuf's nucleus might be slowed due to factors specific to this nucleus, including the biochemical and autonomic properties of the nucleus; nevertheless, it is histologically classified as part of the somatic cell column.

Slow dendritic transport of dissociated mouse hippocampal neurons exposed to aluminum.

We determined the influence of aluminum on dendritic transport, using an in vitro system of dissociated mouse hippocampal neurons. Newly synthesized RNA from dissociated mouse hippocampal neurons was more slowly transported into dendrites in the presence of aluminum chloride when compared to those without the addition of aluminum chloride to the culture medium. Suppression of dendritic transport of newly synthesized RNA may be responsible for the dendritic degeneration observed in aluminum neurotoxicity, eventually leading to neuronal degeneration.

Comparative study of chronic aluminum-induced neurofilamentous aggregates with intracytoplasmic inclusions of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is characterized neuropathologically by chromatolysis, Bunina bodies, hyaline inclusions, skein-like inclusions and axonal spheroids. Aluminum, a known neurotoxin, is the cause of dialysis encephalopathy and is considered to be a causative agent in high incidence foci of ALS in the western Pacific. We have developed an experimental model of motor neuron degeneration in New Zealand white rabbits using chronic low-dose intracisternal administration of aluminum and compared the clinical and neuropathological changes to those of human ALS. Aluminum-inoculated rabbits developed progressive hyperreflexia, hypertonia, limb splaying, gait impairment, muscle wasting, hindlimb paralysis and impaired tonic immobility responses without overt encephalopathic features over a 14-month period. Examination of spinal cords from these animals demonstrated the frequent occurrence and progressive development of anterior horn cell lesions that included small, round, argentophilic perikaryal inclusions similar to hyaline inclusions seen in human ALS. Other inclusions were more condensed and eosinophilic, while still others had neurofibrillary tangle-like morphologies. Axonal spheroids and neuritic thickenings were also prominent and were identical to those seen in human ALS. We believe that the similar and progressive development of neuropathological changes observed in the chronic aluminum-intoxication model, compared to human ALS, warrants further study to aid in understanding the cellular and molecular mechanisms of human motor neuron disease.

Can the controversy of the role of aluminum in Alzheimer's disease be resolved? What are the suggested approaches to this controversy and methodological issues to be considered?

Aluminum (Al) is unquestionably neurotoxic in both experimental animals and certain human diseases. Minute quantities injected intracerebrally into rabbits will induce severe neurological symptoms and neuropathological features of neurodegeneration. Hyper-aluminemia often develops in patients with renal failure being treated with intermittent hemodialysis on a chronic basis, and in severe cases results in an encephalopathy. Uremic adults and premature infants not on dialysis treatment also can develop encephalopathy due to Al toxicity, as is the case when large amounts of alum are used as a urinary bladder irrigant. There are many other examples of Al-induced neurotoxicity; however, the question as to whether Al presents a health hazard to humans as a contributing factor to Alzheimer's disease is still the subject of debate. Several lines of evidence are presented that have formed the basis of the debate concerning the possible pathogenic role for Al in Alzheimer's disease. Important evidence for an Al-Alzheimer's causal relationship is the observation by laser microprobe mass analysis (LMMS) of the presence of Al in neurofibrillary tangles, although there are conflicting data on the extent of the Al deposition. The relatively poor sensitivity of some of the analytical instruments available for these challenging in situ microanalyses could explain the discrepant results, although LMMS and perhaps secondary ion mass spectrometry (SIMS) appear to be sufficiently sensitive. Harmonization of the techniques is an essential next step. There is new evidence that exposure to Al from drinking water might result in cognitive impairment and an increased incidence of Alzheimer's disease. However, these epidemiological studies have inherent problems that must be scrutinized to determine if an association really does exist. An understanding of a possible enhanced bioavailability of Al in this type of exposure, versus other exposures such as antacid intake or industrial exposure, needs to be considered and explored. There has been one promising clinical trial of the treatment of Alzheimer's disease patients with the Al chelator desferrioxamine (DFO). Further studies are needed, and if confirmation is forthcoming then such data could also support an Al-Alzheimer's disease link as well as suggesting that DFO offers potential as a therapeutic agent. The possibility that iron might be the offending agent needs to be considered since DFO is a very strong iron chelator. The significance of Al-induced neurofibrillary degeneration in experimental animals should be assessed especially in light of new data showing that this model exhibits abnormally phosphorylated tau protein structures in the neuronal perikarya. Thus the key questions that must be answered before it can be asserted that Al possesses causal relationship to Alzheimer's disease, are as follows and are addressed in this present discussion: (1) Are there elevations of the concentration of Al in the brains of Alzheimer's disease patients? (2) Is there a relationship between environmental exposure to Al, particularly in drinking water, and an increased risk of Alzheimer's disease? (3) Is treatment with DFO a potentially useful therapeutic approach and to what extent might beneficial effects of DFO implicate Al in the etiology of Alzheimer's disease? (4) Are there similarities between the experimental animal studies and Alzheimer's disease particularly in the development of abnormal forms of tau seen in neurofibrillary tangles? (5) Does Al promote the deposition of the A beta peptide in Alzheimer's disease? (6) Does hyperaluminemia associated with long-term hemodialysis treatment induce neurofibrillary degeneration? If the answer to each of these six questions is yes, then does this assert that Al possesses a causal relationship to Alzheimer's disease? On the other hand, must all six be met to be able to make this assertion?

Bunina body formation in amyotrophic lateral sclerosis: a morphometric-statistical and trace element study featuring aluminum.

Clinico-environmental and pathological variables were obtained from 10 patients with amyotrophic lateral sclerosis using particle-induced X-ray emission spectrometry (PIXE) and morphometric-statistical analysis. Statistical analysis identified a model that maximally predicts the Bb% (frequency of Bunina bodies) from a selected set, four variables: (1) nucleolar index, (2) magnesium (Mg) content, (3) aluminum (Al) content, and (4) duration of illness. Among them, only the Al content proved important. To determine their chemical nature, electron energy loss spectrometry (EELS) was applied at the ultrastructural level; it revealed that within the motor neuron, Al strongly binds to the Bunina body as well as rough endoplasmic reticulum (rER), and lesser strongly to mitochondria and lipofuscin granule. Thus, it is chemically similar to the rER, providing preferential binding sites to aluminum. The Bunina bodies may be an end-product of the nucleic acid dysmetabolism at rER caused by Al along with Mg depletion.

Aluminum-induced model of motor neuron degeneration: subperineurial injection of aluminum in rabbits.

Environmental factors, particularly chronic exposure to aluminum (Al) and manganese (Mn) with dietary deficiency of calcium (Ca) and magnesium (Mg), are speculated to be contributory in the pathogenesis of amyotrophic lateral sclerosis (ALS). However, the mechanisms by which these elements accumulate in the CNS tissues and induce neuronal death are not known. In the present study, we investigated the retrograde transport of Al as a possible mechanism of pathogenesis. Al (as aluminum chloride or maltol) was injected into the subepineurial space of the sciatic nerve with subsequent morphological evaluation of the neurotoxic effect on spinal motor neurons in rabbits. Spheroid/globules, central and peripheral chromatolysis, and neuronal degeneration were observed in the spinal anterior horn in Al-maltol, Al chloride, and maltol treated rabbits to more marked extent than those in uninjected or saline controls. By electron microscopy, the soma and dendrites of neurons in the anterior horn at the fifth lumbar spinal cord in the Al-treated rabbit showed marked edematous change, fragmentation of granular endoplasmic reticulum, increased accumulation of neurofilament, and accumulation of free ribosomes and lipid-droplet-like structures. Horseradish peroxidase (HRP) reactive product was seen in the axons and cytoplasm of Schwann cells of the sciatic nerve in Al-maltol treated rabbits, suggesting that the permeability of the blood-nerve-barrier was increased by injection of Al-maltol. We suggest that Al, subperineurially injected, was absorbed into the spinal cord and induced degeneration of spinal motor neurons in these rabbits. These findings indicate that the retrograde transport of Al into spinal motor neurons via the peripheral nervous system may exacerbate neuronal degeneration in ALS.

Dose-dependent selective suppression of light (NFL) and medium (NFM) but not heavy (NFH) molecular weight neurofilament mRNA levels in acute aluminum neurotoxicity.

We inoculated 5- to 6-week old New Zealand white rabbits intracisternally with either 100, 250, 500, 750, or 1000 micrograms of AlCl3 or 0.9% NaCl and correlated the extent of cervical motor neuron neurofilamentous inclusion formation at 48 h postinoculation with alterations in neurofilament (NF) mRNA levels. RNA was isolated from cervical spinal cord by the guanidine isothiocyanate method and individual RNA samples were normalized for poly(A+) content. Northern blot analysis was performed with cDNA probes for light (NFL), medium (NFM), and heavy (NFH) neurofilament subunit protein or with oligonucleotide probes for alpha-tubulin or actin. No significant alteration in the levels of alpha-tubulin, actin, or NFH mRNA were observed, regardless of the aluminum dose. In contrast, dose-dependent reductions in NFL and NFM mRNA levels occurred in direct proportion to the extent of neurofilamentous inclusion formation. While inoculums of NaCl or 100 or 250 micrograms AlCl3 induced neither inclusion formation or alterations in mRNA levels, both inclusion formation and reductions in the levels of NFL and NFM mRNA occurred thereafter, becoming maximal with inoculums of 1000 micrograms AlCl3. These experiments indicate that intracisternally administered AlCl3 acutely suppresses NFL and NFM mRNA levels without affecting those of NFH. This pattern is in distinct contrast to the uniform reductions of all NF mRNA transcript levels during neurogenesis or following axotomy, indicating a specific effect of aluminum upon steady-state levels of NF mRNA that correlates with the induction of neurofilamentous aggregates.

Relationship of microglia and scrapie amyloid-immunoreactive plaques in kuru, Creutzfeldt-Jakob disease and Gerstmann-Sträussler syndrome.

Kuru, Creutzfeldt-Jakob disease (CJD) and Gerstmann-Sträussler syndrome (GSS) are transmissible dementias affecting humans characterized neuropathologically by intraneuronal vacuolation, spongiform change, astrocytic hypertrophy and hyperplasia and the variable presence of amyloid plaques. It has been suggested that microglia are amyloid-forming cells, which play an essential role in amyloid plaque formation. To study the relationship between microglia and amyloid plaques in kuru, CJD and GSS, cerebellar tissues were examined by the double-immunostaining technique using anti-ferritin antibodies as the microglial marker and anti-scrapie amyloid antibody as plaque marker. Ferritin-immunoreactive microglia were observed interdigitating with and among unicentric, multicentric and diffuse types of scrapie amyloid-immunoreactive plaques and were found to a lesser extent in the neuropil. In kuru and CJD, scrapie amyloid-immunoreactive plaques were predominantly unicentric and were observed in the granular layer. In kuru, 53% of the amyloid plaques were associated with microglia, whereas only 30% of plaques in CJD were. In contrast, scrapie-amyloid-immunoreactive plaques in GSS were of the multicentric type, predominantly observed in the molecular layer, and 90% of these plaques were associated with microglia. Our data indicate that microglia are frequently associated with scrapie amyloid-immunoreactive plaques in GSS, less commonly in kuru and to a much lesser extent in CJD, suggesting that microglia may play a variable but important role in the formation of plaques in the transmissible spongiform encephalopathies.

Rare neuropil threads in amyotrophic lateral sclerosis and parkinsonism-dementia on Guam and in the Kii Peninsula of Japan.

Using three different silver impregnation methods and antisera against microtubule-associated protein-tau (MAP-tau) and amyloid beta/A4 protein, we demonstrated abundant neurofibrillary tangles (NFTs), rare senile plaques, absence of amyloid angiopathy and rare MAP-tau- and silver-positive neuropil threads in the hippocampus of patients with amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia (PD) on Guam and in the Kii Peninsula of Japan. In contrast, abundant neuropil threads, NFTs, senile plaques with associated dystrophic neurites and amyloid angiopathy were confirmed in Alzheimer disease patients. These observations indicate that there may be important factor(s) responsible for the difference in the deposition and distribution of amyloid beta/A4 protein and MAP-tau between Pacific ALS and PD and Alzheimer disease.

Immunocytochemical and ultrastructural evidence of dendritic degeneration in motor neurons of aluminum-intoxicated rabbits.

Using immunocytochemical and ultrastructural methods, we observed extensive and characteristic dendritic changes in motor neurons of rabbits inoculated intracisternally with aluminum phosphate. Anti-microtubule-associated protein 2 immunostaining revealed markedly reduced immunoreactivity in motor neuron dendrites and a reduced number of dendritic trees in aluminum phosphate-intoxicated rabbits. These dendritic changes were confirmed at the ultrastructural level; neurofilamentous accumulations, membranous inclusions and disrupted microtubules were common features of motor neuron axons. These observations suggest that dendrites are characteristically involved in aluminum intoxication in addition to the widely reported accumulation of phosphorylated neurofilament in perikarya and axons.

Ultrastructural neuropathology of chronic wasting disease in captive mule deer.

Chronic wasting disease (CWD), a progressive and uniformly fatal neurological disorder, is characterized neuropathologically by intraneuronal vacuolation, spongiform change of the neuropil and astrocytic hyperplasia and hypertrophy. Ultrastructural neuropathological findings consist of (1) extensive vacuolation in neuronal processes, within myelin sheaths, formed by splitting at the major dense lines or within axons; (2) dystrophic neurites (dendrites, axonal preterminals and myelinated axons containing degenerating mitochondria and pleomorphic, electron-dense inclusion bodies); (3) prominent astrocytic gliosis; (4) amyloid plaques; and (5) giant neuronal autophagic vacuoles. Other findings include activated macrophages and occasional spheroidal structures containing densely packed fibrillar material of unknown origin, abundant structures suggestive of degenerating microtubules entrapped in filamentous masses, vacuoles and myelin figures. Similar findings have been previously observed in scrapie-infected hamsters and Creutzfeldt-Jakob disease (CJD)-infected mice, bovine spongiform encephalopathy, and CJD indicating that CWD in captive mule deer belongs to the subacute spongiform encephalopathies (transmissible brain amyloidoses).

Morphometry of spinal motor neurons in amyotrophic lateral sclerosis with special reference to chromatolysis and intracytoplasmic inclusion bodies.

Lewy body-like hyaline inclusions (LBI), Bunina bodies (BB) and central chromatolysis are characteristic neuropathological features of spinal motor neurons in amyotrophic lateral sclerosis (ALS). Using histometric methods, we studied the spinal motor neurons of 4 patients with sporadic ALS and 3 neurological control patients to determine the possible relationship between these neuropathological features and cytoplasmic, nuclear and nucleolar size. In an ALS patient with a very rapid clinical course, many neurons with LBI were observed. Enlargement of nucleolar size and the nucleolar/nuclear ratio of neurons with LBI or BB were the only histometric difference compared to those of normal-appearing neurons. In ALS patients with an average clinical course, the number of neurons with LBI was lower, the number of neurons with BB was higher, and the nuclear and nucleolar sizes were smaller than those of normal-appearing neurons, particularly in chromatolytic neurons without LBI or BB. These data raise the possibility that motor neurons with LBI may represent an early stage in the neurodegenerative process, when the rate of protein synthesis is elevated as evidenced by their larger nucleolar size. Thus, the causative agent(s) of ALS may initially stimulate protein synthesis while in turn leading to down regulation of certain luxury function genes, culminating in neuronal dysfunction and death.