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Biomedical subjects

A Nezu

Publications and source records attributed to A Nezu.

At least 55 records · Page 3Linked to original sources
PubMed1997

Magnetic stimulation of motor cortex in children: maturity of corticospinal pathway and problem of clinical application.

The developmental profile of the electromyographic responses to transcranial magnetic stimulation (TMS) was studied in 46 neurologically normal children aged from one to 14 years, compared with data in 10 normal control adults. To obtain motor evoked potentials (MEPs) from the first dorsal interosseous muscle in the resting state, the motor cortex was stimulated through a circular coil with the stimulus intensity set at 10% above the threshold intensity for eliciting MEPs. Reproducible MEPs were obtained in all but the children aged below 2 years, and the threshold intensity and central motor conduction time (CMCT) showed a linear decrease with maturation. The MEP amplitude changed little until 9 years of age, but it tended to increase between 10 years and adulthood. The MEP duration, which was not influenced by age, was less than 16 ms over the ages studied. The present data suggest that maturity of the corticospinal motor pathway that controls the intrinsic hand muscles is electrophysiologically complete at 13 years of age. Among the parameters of MEPs, CMCT and MEP duration may be useful for evaluating impairment of the corticospinal tracts in children aged 2 years and older.

Adolescent↗
PubMed1997

Alternating hemiplegia of childhood: report of a case having a long history.

We examined a patient with alternating hemiplegia of childhood (AHC) who had over a 23-year history of AHC to investigate the origin of the neurological deterioration with increasing age. Hemiplegic attacks had occurred consistently at a frequency of a few per week since infancy, and he first experienced attacks of cerebellar ataxia at the age of 23 years. Intellectual impairment, dysarthria, dystonic posturing, and a wide-based gait had been slowly progressive, but they had been stable since he turned twenty. The electromyographic response to transcranial magnetic stimulation was normal between attacks and showed reversible alteration during an attack. MRI revealed slight dilatation of the lateral ventricles, and MR angiography showed normal cerebral blood flow. Proton MR spectroscopy between attacks showed normal peak area ratios for N-acetyl groups, choline-containing compounds, and creatine and phosphocreatine, and it also demonstrated no lactic peak. 123I-IMP SPECT between attacks demonstrated diffuse cerebral hypoperfusion despite no evidence of ischemic change in the above MR study. These results suggest that the slowly progressive neurological deficits are due to the primary underlying pathology rather than the secondary neuronal loss as a result of frequent ischemic attacks.

Adult↗
PubMed1997

Two cases of essential myoclonus, epilepsy, mental retardation and anxiety disorders.

We examined an 18-year-old female and an 18-year-old male with mild mental retardation who suffered from the oscillatory form of sporadic essential myoclonus from an age of 3 years. Although the generalized oscillatory myoclonus resembled severe essential tremor, surface electromyography revealed small myoclonic jerks with frequencies of 6-8 Hz. As concomitant symptoms, the female case exhibited overanxious irritability from early childhood and generalized epileptic seizures occurred from the age of 4 years. In the male case, an obsessive-compulsive disorder and photosensitive convulsive seizures were persistently noted from early childhood. All their symptoms had been stable for at least the last 10 years. Thus, although non-progressive tremulous movements are rare in early childhood, sporadic essential myoclonus is causative. In contrast to hereditary essential myoclonus, sporadic essential myoclonus is considered to be more heterogeneous, especially in the various associated symptoms.

Adolescent↗
PubMed1997

Clinical and radiologic improvements in mitochondrial encephalomyelopathy following sodium dichloroacetate therapy.

We administered sodium dichloroacetate (DCA), which reduces the circulating lactate and pyruvate concentrations by stimulating the activity of the pyruvate dehydrogenase complex (PDHC), to three children with mitochondrial encephalomyelopathy. Significant clinical, biochemical and radiologic improvements were obtained following DCA therapy (approximately 30 mg/kg per day, divided into three doses). All three patients had non-pyruvate dehydrogenase complex (PDHC) deficiencies: two exhibited Leigh syndrome (complex I deficiency and unknown etiology), and one abnormal myelination (multienzyme deficiency), demonstrated on magnetic resonance imaging (MRI). The lactic and pyruvic acid concentrations in serum and cerebrospinal fluid (CSF) were decreased significantly by the oral DCA treatment. The lactic acid peak on MR spectroscopy also markedly decreased in parallel with the CSF level. In addition, the brain lesions observed on MRI were improved in all patients. No exacerbation was observed in any of the patients, who have been followed-up more than 21 months following the DCA therapy. These results suggest that DCA therapy should be considered in all patients with a mitochondria-related enzyme deficiency.

Brain↗
PubMed1996

Effect of digitalis on conduction dysfunction in Pelizaeus-Merzbacher disease.

We studied the effect of digitalis on nerve conduction dysfunction in Pelizaeus-Merzbacher disease (PMD). The patients were three Japanese boys with PMD, aged 7-10 years. Digitalis was administered orally in a daily dose of 0.06 mg/kg for 2 consecutive months, and the obtained serum concentrations ranged from 0.33 to 0.55 ng/ml. The digitalis therapy induced slight improvement of severe dysarthria and cognitive dysfunction in the two older patients. Electrophysiological examinations revealed the following results: In brainstem auditory evoked potentials (BAEPs), while waves II (or III) to V were absent before treatment, on treatment all waves of BAEPs except a wave IV were restored in all patients. While visual evoked potentials (VEPs) in response to transient flash stimulation showed markedly prolonged latencies before treatment, digitalis produced a mild, although not statistically significant, shortening of the latency of N160. There were also no significant changes in inter-peak amplitudes of VEPs. Transcranial cortical magnetic stimulation continued to fail to elicit motor evoked potentials of the first dorsal interosseous muscles in all patients. Thus, although the serum concentrations were insufficient to elicit favorable therapeutic effects, digitalis therapy provided slight relief of clinical symptoms with evidence of improvement of conduction dysfunction. It is suggested that patients with PMD may respond to symptomatic treatment modulating nerve conduction.

Child↗
PubMed1996

Hypertrophic neuritis due to chronic inflammatory demyelinating polyradiculoneuropathy (CIDP): a postmortem pathological study.

A postmortem pathological study of a 65-year-old woman with hypertrophic neuritis associated with hand tremor and limb ataxia is described. There were many onion bulbs and loss of myelinated nerve fibers in the peripheral nerves, including the facial and subserosal visceral nerves. The hypertrophic neuritis was caused by chronic inflammatory demyelinating neuropathy (CIDP), in which interstitial amorphous substances in the endoneurium and onion bulb formation might contribute to nerve swelling. We speculate that visceral autonomic nerves as well as somatic peripheral nerves are involved in patients with a long clinical CIDP course and that peripheral nerve pathology in this disorder shows more heterogeneous changes than previously recognized.

Aged↗
PubMed1996

Involvement of platelet cyclic GMP but not cyclic AMP suppression in leukocyte-dependent platelet adhesion to endothelial cells induced by platelet-activating factor in vitro.

1. Incubation of endothelial cells with platelets in the absence or the presence of PAF (10 nM) markedly increased platelet cyclic AMP levels, which were significantly decreased by indomethacin (3 microM). Co-incubation of endothelial cells and platelets with polymorphonuclear leukocytes (PMNs) did not change the platelet cyclic AMP levels. 2. Incubation of endothelial cells with platelets in the absence of PAF increased platelet cyclic GMP levels, which were increased 3.5 fold by PAF. These cyclic GMP levels were significantly decreased by NG-nitro-L-arginine (100 microM), and completely by methylene blue (10 microM). When endothelial cells and platelets were co-incubated with PMNs, the cyclic GMP level in the cell mixture was 42.5 and 65.3% lower than that in endothelial cells and platelets without and with PAF stimulation, respectively. 3. PAF induced platelet adhesion to endothelial cells only when PMNs were present. Methylene blue dose-dependently potentiated the PMN-dependent platelet adhesion induced by PAF, although it had no effect in the absence of PMNs. 4. Sodium nitroprusside and 8-bromo cyclic GMP but not dibutyryl cyclic AMP significantly, although partially, inhibited the platelet adhesion. Inhibition of cyclic GMP-specific phosphodiesterase by zaprinast slightly inhibited the PMN-induced platelet adhesion and potentiated the inhibitory effect of 8-bromo cyclic GMP, while these drugs markedly inhibited the adhesion of platelet aggregates induced by PMN sonicates. 5. These results suggest that the impairment by activated PMNs of EDRF-induced platelet cyclic GMP formation is involved in part in the mechanism of PMN-dependent platelet adhesion to endothelial cells induced by PAF in vitro. The precise mechanism still remains to be clarified.

Animals↗
PubMed1996

[Hyperintense brain lesions on T1-weighted MRI after parenteral nutrition].

We experienced five children having T1-shortening lesions in basal ganglia or thalami on magnetic resonance imaging (MRI), which were supposed to be caused by manganese (Mn) overdoses. Instead of the presence of above mentioned lesions, no neurological manifestations corresponding to them had developed in all patients. This observation suggests that a MRI is useful for detecting the side effects caused by overdoses of Mn in patients having parenteral nutrition.

Adolescent↗
PubMed1996

A duplicated PLP gene causing Pelizaeus-Merzbacher disease detected by comparative multiplex PCR.

Pelizaeus-Merzbacher disease (PMD) is an X-linked dysmyelinating disorder caused by abnormalities in the proteolipid protein (PLP) gene, which is essential for oligodendrocyte differentiation and CNS myelin formation. Although linkage analysis has shown the homogeneity at the PLP locus in patients with PMD, exonic mutations in the PLP gene have been identified in only 10%-25% of all cases, which suggests the presence of other genetic aberrations, including gene duplication. In this study, we examined five families with PMD not carrying exonic mutations in PLP gene, using comparative multiplex PCR (CM-PCR) as a semiquantitative assay of gene dosage. PLP gene duplications were identified in four families by CM-PCR and confirmed in three families by densitometric RFLP analysis. Because a homologous myelin protein gene, PMP22, is duplicated in the majority of patients with Charcot-Marie-Tooth 1A, PLP gene overdosage may be a important genetic abnormality in PMD and affect myelin formation.

Base Sequence↗
PubMed1995

MvaI polymorphism in the proteolipid protein (PLP) gene.

We report a rare polymorphism in the human proteolipid protein (PLP) gene. A synonymous mutation, 168 A-->G, was detected in exon 2 of the PLP gene. Mutations in this gene have been reported in some cases of Pelizaeus-Merzbacher disease.

Base Sequence↗
PubMed1995

Improvement of lesions shown on MRI and CT scan by administration of dichloroacetate in patients with Leigh syndrome.

Brain lesions exhibited on MRI and CT scan in 2 patients with mitochondrial encephalomyelopathy representing Leigh syndrome were improved by administration of dichloroacetate (DCA). One patient had pyruvic acid dehydrogenase complex (PDHC) deficiency, the other had complex I deficiency. The efficacy of DCA was transient in the patient with the PDHC deficiency, lasting for about 2.5 months. The patient died at the age of 6, about 2 years after the initiation of DCA treatment. DCA administration was started in the patient with complex I deficiency when he was 15 months old and it is still effective at his present age of 24 months. His motor ability is developing, and he could walk without support at the age of 19 months. DCA administration should be tried in patients with mitochondrial diseases.

Dichloroacetic Acid↗
PubMed1994

Acute leucoencephalopathy during cyclosporin A therapy in a patient with nephrotic syndrome.

A 13-year-old girl with nephrotic syndrome (NS) developed acute leucoencephalopathy during combination therapy with cyclosporin A (CyA) and prednisolone (PSL). The patient had a generalized motor seizure followed by coma at 19 days after CyA administration. Magnetic resonance scanning performed on the 1st hospital day revealed white matter lesions in the subcortices of the parietal and occipital lobes, brain stem and cerebellum. These lesions had completely resolved on the 10th hospital day. This episode might be caused by CyA because the clinical course and laboratory data revealed neither inflammation nor other causative factors. To our knowledge, this is the first report of acute leucoencephalopathy during combination therapy with CyA and PSL in a patient with NS.

Acute Disease↗
PubMed1994

Two cases of glutaric aciduria type 1: clinical and neuropathological findings.

We report clinical and neuropathological studies of 2 patients with glutaric aciduria type 1. A 10-month-old male with involuntary movements expired suddenly at home. The second, a 15-year-old female, died after three episodes of acute encephalopathy including a Reye syndrome-like episode and an episode of severe hypoglycemia. Hypocarnitinemia was also present. Selective involvement of type II muscle fibers was observed during the Reye syndrome-like episode. Magnetic resonance imaging of the 2 patients showed marked widening of the sylvian fissure, atrophy of the basal ganglia, and white matter lesions. Neuropathology of the 10-month-old patient showed: (1) temporal and frontal lobe hypoplasia, (2) degeneration of the putamen and the pallidum, (3) mild status spongiosus in the cerebral white matters, (4) heterotopic neurons in the cerebellum, and (5) hypoplasia of the cerebral white matter. This patient appeared to manifest a migration and/or maturation abnormality of the brain as well as previously observed basal ganglia and white matter degeneration.

Adolescent↗
PubMed1994

Symmetrical external capsule lesions in a patient with herpes simplex encephalitis.

A 7-year-old boy had symmetrical transient high signal lesions in the external capsules on T2-weighted image during the recovery phase of herpes simplex virus (HSV) encephalitis. Although this finding has never been reported in HSV or other viral encephalitis, a postinfectious allergic mechanism is suspected in this patient. With the development of magnetic resonance imaging and other neuroimaging studies, a more detailed analysis of central nervous system is now possible.

AIDS Dementia Complex↗
PubMed1994

[A case of agammaglobulinemia with chronic progressive encephalopathy].

We report a 21-year-old man with agammaglobulinemia and chronic progressive encephalopathy. The patient was diagnosed as having X-linked agammaglobulinemia at 6 months of age, and gamma globulin supplementation was initiated. He exhibited normal development until he was 11 years old, when he showed a decline in school performance and a personality change. Computed tomography images at that time disclosed diffuse cerebral atrophy. Several generalized tonic-clonic convulsions, myoclonus and spasticity appeared at the age of 13 years. He lost his ability to walk and speak at the age of 17 years old. He is currently 21 years old and displays severe mental deterioration and spastic tetraplegia. Magnetic resonance imaging showed progressive diffuse cerebral atrophy with no change in intensity. The cerebellum and the brain stem were relatively well maintained. Viral isolations were negative and serum antibody titers for rubella, measles, and human immune deficiency virus were not elevated. Our patient's symptoms resemble those previously reported as chronic progressive encephalopathy without viral isolation. This condition may be a complication of agammaglobulinemia. It is possible that the encephalopathy of our patient has the same etiology as that described in the other reports. Further attempts to identify the etiology of the encephalopathy using molecular techniques are necessary.

Adult↗
PubMed1992

[A case of Fahr's disease accompanied with persistent vitreous artery].

Serial imaging studies in a 16-year-old female affected by Fahr's disease accompanied with persistent vitreous artery were performed. She suffered from chronic subdural hematoma, which was re-moved at the age of 5 months. Brain CT scan performed at the age of 4 revealed calcified lesions at the corticomedullary junctions in the frontal lobes of cerebrum. Yearly repeated CT scans revealed an increasing number of the calcified lesions, which were observed at the cortico-medullary junction of cerebrum, globus pallidus, thalami and dentate nuclei of the cerebellum. Calcifications have not increased in the last 4 years. Laboratory examinations of serum and urine failed to prove any abnormalities. She also had bilateral persistent vitreous arteries. The combination of these rare two diseases may have occurred coincidentally, but there is a possibility that the capillary dysfunction played a role in the pathogenesis of two diseases.

Adolescent↗
PubMed1991

Roles of a subependymal nodule of tuberous sclerosis on pathophysiology of epilepsy.

Polysomnographies (PSG) were performed on two cases with tuberous sclerosis (TS), both having subependymal nodules on the medial wall of the caudate nucleus adjacent to the thalamostriatal sulci. Clinically one had suffered from infantile spasm and which later turned out to be complex partial seizure with a rotation toward the right. The other had developed tonic seizure on the right with a rotation toward the left in early childhood. Clinico-pharmacological studies revealed the existence of synaptic supersensitivity of the dopamine (DA) receptor in the left caudate and PSG confirmed the synaptic supersensitivity of the former, while in the latter case, it suggested a decrease in DA activity on the left. Subependymal nodules in the caudate nucleus could cause a reduction in the DA transmission and develops synaptic supersensitivity after suffering from TS.

Adolescent↗