Serial magnetic resonance imaging shows separate medial and lateral medullary infarctions resulting in the hemimedullary syndrome.
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Biomedical subjects
Publications and source records attributed to G Sobue.
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We compared the CAG repeat length and the severity of the brainstem and cerebellar atrophy visualized by MRI in 30 patients with Machado-Joseph disease. We found a strong correlation between the CAG repeat number and the quotient of the degree of atrophy divided by age at examination. These results suggest that the rate of disease progression is dependent on the CAG repeat size and disease progression may commence at birth.
A persistent trigeminal artery (PTA) represents an embryonic vascular anastomosis connecting the carotid and basilar arterial systems. Little is known about its protective role in cases of basilar artery occlusion. We followed up a 63-year-old man who had suffered a brain stem infarction due to basilar artery stenosis and was found to have a PTA. Although a second brain stem infarction due to basilar artery occlusion developed, the circulation to the brain stem was well maintained via collateral flow from the PTA, and the patient demonstrated good recovery. A PTA may function as an anastomosis between the carotid and basilar systems, thus preventing a more serious infarction.
Visual disturbance, hypertension, convulsions, and unconsciousness developed in a 70-year-old man after cisplatin chemotherapy and upper-limb amputation for osteosarcoma. MR imaging revealed bilateral reversible abnormalities in the occipital, parietal, and frontal white matter. Clinical and neuroradiologic features corresponded to reversible posterior leukoencephalopathy syndrome (RPLS), which some immunosuppressive and chemotherapeutic drugs have been reported to trigger. Cisplatin may be among these drugs. Our patient also had hypomagnesemia, which may have figured in the pathophysiology.
Recent advances on pathogenetic mechanism and therapeutic approach for Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIPD) were briefly reviewed. As for GBS, an axonal form has been recognized as a clinicopathological variant, in which Campylobacter jejuni infection and elevated anti-GM1 antibody tires are frequently observed. Other anti-glycolipid antibodies to GQ1b, GD1b and GM2 would also be significant as a determinant factor for a clinical phenotype. Beneficial effects of IVIg therapy and plasmapheresis have been established. Although CIDP has also been considered to be demyelinating neuropathy, axonal pathology is frequently noted, and in such cases, a substantial motor neuron loss is present. Clinical recovery in the cases with high anti-MAG and anti-SGPG titers is not necessarily favorable. Corticosteroid therapy, plasmapheresis and IVIg have been all established as therapies beneficial for CIDP.
We studied the therapeutic characteristics of double filtration plasmapheresis (DFPP) in 14 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The patients were classified into 2 subgroups of the responders (7 patients) and the non-responders (7 patients) to DFPP. The responders to DFPP were designated as those showing the improvement 2 or more grades in measures the activity of daily living by the modified Rankin scale (MRS). All these patients underwent neurological assessment, CSF study, electrophysiological studies at the beginning and end of treatment. Sural nerve biopsy study was performed in 10 cases. Neurological function was assessed serially using a quantitative neurological disability score (NDS). At the beginning of treatment, there were no significant differences in various measurements between the responders and the non-responders except for the frequency of demyelination. In responders, significant improvement was found in mean changes in MRS, NDS, motor nerve conduction velocity, compound muscle action potential, distal motor latency, while in non-responders, all measures remained unchanged or worsened. Muscle wasting was seen in 3/7 responders and 4/7 non-responders, and denervation potentials in needle EMG were seen in 1/7 responders and 3/7 non-responders. Four patients of the responders were classified as chronic relapsing course, and 6 patients of the non-responders as chronic progressive course. We conclude that DFPP was useful for the subgroups of CIDP patients, but the underlying immuno-pathological background that determine the efficacy of plasmapheresis should be elucidated.
We reported MRI findings in a 49-year-old woman with clinically diagnosed Creutzfeldt-Jakob disease (CJD). She was admitted to our hospital because of confusion, which initially appeared 5 weeks prior and was rapidly worsened. Two weeks later, she developed myoclonic jerks in her extremities with periodic synchronous discharges on EEG. Six months later, she became mutic. Brain MRI at 3 weeks after the admission demonstrated high signal intensities in the bilateral caudate nuclei and putamina on T2 weighted images (T2WIs). Diffusion weighted images (DWIs) showed hyperintensities in the basal ganglia and in the parietal and occipital cortices. Five weeks later, the abnormal intensities in the basal ganglia were still observed on T2WIs but decreased on DWIs. Five months later, the increased signal intensities in the basal ganglia had disappeared both on T2WIs and DWIs, but new hyperintensities appeared in the insula and the temporal area on DWIs. We concluded that DWIs may be useful for the demonstrations of a lesion in the cerebral cortex and the spread of lesions.
To evaluate the clinical characteristics of Machado-Joseph disease (MJD) with reference to CAG repeat length and disease duration, we analyzed neurologic findings in 108 patients from 84 families. The majority of MJD patients presented with an ataxic gait as the initial symptom. Dysarthria and nystagmus were observed from an early stage. Bulging eyes, muscle atrophy and bradykinesia developed later. Patients with a shorter CAG repeat length or later onset had more frequent involvement of proprioceptive sensory deficit. Incidence of abnormal reflexes, tones, and proprioceptive sensation was not associated with disease duration, but with CAG repeat length. Based on these results, we propose a new clinical classification: type A (juvenile type), with hyperreflexia and dystonia, but without a proprioceptive sensory deficit; type C (adult type), with hyporeflexia and a proprioceptive sensory deficit, but without dystonia; and type B (intermediate type), the remaining patients with a mixed presentation.
Lipofuscins are intracellular fluorescent pigments accumulating in the central nervous system (CNS) with aging and degenerative processes such as Alzheimer's disease (AD). Although they are thought to be lipid peroxidation products derived from malondialdehyde, their biogenesis remains controversial. We further characterize the chemical nature of lipofuscins in brain tissues from AD patients and normal aged subjects. Advanced glycation end products (AGEs), pentosidine and carboxymethyllysine (CML), were identified by appropriate specific antibodies. They have physicochemical properties similar to those of lipofuscin and also increase with aging. Pentosidine and CML were identified in the neuronal perikarya and the extraneuroperikaryal deposits of both the AD and aged brain. Pentosidine, but not CML, was present in the fiber-like structure within the neuropil and the core of classical senile plaque. In the brain of young subjects without CNS disease, pentosidine and CML staining was faint. Pentosidine and CML co-localized with lipofuscin pigments in the neuronal perikarya of both the AD and aged brain. We demonstrate for the first time that lipofuscin is constituted not only of lipid peroxidation products but also from glycation products which may be the origin of fluorescent pigments. Lipofuscins should thus be considered as fluorescent pigments generated by lipid- and sugar-derived Schiff base-protein polymers.
We investigated the transforming activity of the ret proto-oncogene with a mutation in cysteine 609, 611, 618, 620, 630, or 634 detected in patients with multiple endocrine neoplasia type 2A (MEN 2A), familial medullary thyroid carcinoma (FMTC), or Hirschsprung's disease. Of these cysteine mutations, codon 634 mutations are known to be correlated with the development of MEN 2A, whereas codon 609, 618, or 620 mutations were detected in two-thirds of FMTCs and in several cases of Hirschsprung's disease. Analysis of a total of 18 mutant genes revealed that codon 634 mutations have the highest transforming activity. The activity of ret with a codon 609, 611, 618, or 620 mutation and with a codon 630 mutation was approximately 3- to 5-fold and 2-fold lower than that of ret with a codon 634 mutation, respectively. In addition, different amino acid substitutions for the same cysteine displayed comparable transforming activity. The expression of the cell surface form of Ret with codon 609, 611, 618, or 620 mutation was very low compared with that of Ret with codon 634 mutation, indicating that the former four mutations might impair transport of Ret to the plasma membrane, as observed for several Hirschsprung mutations affecting the Ret extracellular domain. These results thus suggest that mutations in cysteine 609, 611, 618, or 620 may have the potential to develop Hirschsprung's disease in addition to MEN 2A and FMTC.
To elucidate the effect of heat stress on the sympathetic nervous system, we evaluated changes in muscle sympathetic nerve activity (MSNA), plasma arginine vasopressin (AVP), tympanic temperature, skin blood flow, cardiac output, mean blood pressure, and heart rate in 9 subjects in response to acute heat stress induced by raising the ambient temperature from 29 to 34 degrees C and then to 40 degrees C. With the heat exposure, MSNA was significantly increased with a significant increase in tympanic temperature. Skin blood flow and heart rate were also significantly increased, while mean blood pressure tended to decline and cardiac output tended to increase. The combination of the increased MSNA and skin blood flow may have caused the redistribution of the circulatory blood volume from the muscles to the skin, facilitating convection heat loss. The increases in MSNA counteracted the lowered blood pressure during heat exposure. Thus, the increased MSNA may play an important role both in thermoregulation and in the maintenance of blood pressure against heat stress.
N-Methyl(R)salsolinol was found to be an endogenous dopaminergic neurotoxin inducing parkinsonism in rodents and to increase in the cerebrospinal fluid of parkinsonian patients. The amounts of N-methyl(R)salsolinol and related compounds in the human brain regions were quantitatively analyzed. Only the (R)-enantiomer of salsolinol derivatives were detected, which suggests their enzymatic synthesis in situ. In the nigro-striatal system, the concentration of N-methyl(+)salsolinol was higher than in the frontal cortex, and its oxidized catechol isoquinolinium ion was detected only in the substantia nigra significantly. The accumulation of these neurotoxins in the nigro-striatal region might account for selective cell death of dopamine neurons in the substantia nigra of Parkinson's disease.
To determine whether the Fas-Fas-ligand mediated apoptosis occurs in the pathologic process of human muscle diseases, we examined the expression of Fas antigen, Fas-ligand messenger RNA, and chromosomal DNA fragmentation in the muscle cells of patients with a variety of human muscle disorders. The present study demonstrated that the Fas antigen of a whole molecule was expressed on the muscle fibers of patients with muscle wasting diseases. However, the apoptotic process did not occur in the muscle cells, and there was no evidence of Fas-ligand synthesis in the diseased muscle tissue. Our data suggest that the expression of Fas antigen on fibers in diseased muscle is related to unknown biological functions other than "apoptosis" in the process of muscle fiber injury.
Charcot-Marie-Tooth disease type 1A (CMT1A) is a common autosomal dominant demyelinating peripheral neuropathy. Most patients with CMT1A have been found to have a 1.5 megabase tandem DNA duplication in chromosome 17p11.2-12. Meiotic unequal crossover mediated by the CMT1A-REP repeat is a proposed mechanism for generation of the duplication in CMT1A and a reciprocal deletion seen in hereditary neuropathy with liability to pressure palsies. Testing for the CMT1A duplication is frequently the first step in the molecular diagnosis of patients with suspected inherited demyelinating neuropathy. We used a 1.0 kb EcoRI-PstI DNA fragment (pHK1.0P) from the proximal CMT1A-REP repeat as a probe for Southern blot analysis and detected increased gene dosage in CMT1A by determining measuring radioactivity ratios with a photostimulated luminescence imaging plate. We found that this method is useful for rapid diagnosis of the DNA duplication associated with CMT1A.
Loss of sweating is a characteristic feature of multiple system atrophy (MSA) with autonomic failure, and widespread anhidrosis may lead to hyperthermia and collapse in a hot environment. Calcitonin gene-related peptide (CGRP) is present in the periglandular nerves around sweat glands and is a strong stimulant of methacholine (MCH)-mediated cholinergic sweating. The present study evaluated CGRP-related regulation of cholinergic sweating in patients with MSA. CGRP-induced potentiation of MCH-mediated cholinergic sweating was significantly reduced in MSA patients as compared with normal age-matched controls. These results suggest that regulation of sweating is extensively affected in MSA as a consequence of peptidergic dysfunction.
We evaluated plasma noradrenaline (NA) levels at test and during head-up tilt test in 20 patients with sporadic amyotrophic lateral sclerosis (ALS). Their fasting plasma NA levels ranged from 195 to 4227 pg/ml. The average plasma NA level was 483 pg/ml in five ambulatory patients, 341 in two wheelchair-bound patients, 1264 in 11 bedridden patients, and 208 in two respirator-dependent patients whose disability grading was the worst among the four groups. Arterial carbon dioxide (PCO2) was evaluated as a measure of respiratory function. The coefficient of correlation between PCO2 and plasma NA was r = 0.654 (p < 0.01). Either respiratory failure or lower motor neuron dysfunction may relate to the elevation of plasma NA levels. In the two bedridden patients, plasma NA levels and heart rate at rest increased significantly as the disease progressed. Cardiovascular responses to head-up tilting were normal. These data suggest that the elevation of plasma NA levels may be related to progression of respiratory failure and lower motor neuron dysfunction. In conclusion, sympathetic hyperactivity in ALS is considered to be not primary, but secondary to somatic motor disabilities and respiratory failure.
A quantitative study was performed on spinal cord lesions in seven patients with X-linked recessive spinal and bulbar muscular atrophy. The myelinated fiber density of the lateral corticospinal tracts at the T7 cord level was well preserved for both large and small myelinated fibers. On the other hand, neurons in the L4 ventral horn were markedly depleted; marked loss was noted of the large alpha and medium-sized gamma motor neurons located in the lateral and medial nuclei as well as the small neurons in the intermediate zones of the ventral horn. These results suggest that myelinated fiber density and fiber-size distribution in the corticospinal tract are well preserved and that neuronal loss in the ventral horns is not restricted to alpha and gamma motoneurons but also involves small interneurons.
The crossover breakpoints for Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP) are located in the CMT1A-REP repeat flanking a 1.5-Mb region of chromosome 17p11.2-12. The precise locations of the breakpoints are heterogeneous, and we analyzed the relative frequency distribution of breakpoints in 33 unrelated Japanese CMT1A and 3 unrelated HNPP families. The CMT1A-REP repeat region was divided into five regions, A, B, C, D and E, based on restriction site differences between the proximal and distal CMT1A-REP repeats. The frequency distribution of breakpoints within the CMT1A-REP repeat in the Japanese patients was 3% in region A, .78% in B/C and 19% in D, which is similar to that in Caucasian patients. This result also indicates that an 8-kb region defined by region B/C is a recombinational hotspot within the CMT1A-REP repeat in Japanese patients.