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Biomedical subjects

M Segawa

Publications and source records attributed to M Segawa.

At least 163 records · Page 9Linked to original sources
PubMed1984

Rett syndrome--clinical studies and pathophysiological consideration.

Eleven female patients with Rett syndrome were evaluated for detecting the pathogenesis. Clinical symptoms were characterized by their orderly sequence of occurrence of particular symptoms at particular ages starting from early infancy, and their progression. Increment of head circumference tapered from late infancy, resulting in microcephalus which corresponded with the clinical features. Surface EMG revealed the tremulous rhythmic discharge underlying the characteristic stereotyped movement of the hands. Serial polysomnographical examinations showed abnormalities of the tonic and phasic components of sleep and increment of % REM stage with age. The results of these clinical, laboratory and polysomnographical examinations were discussed, comparing with other neurological diseases and knowledge of animal experiments. From these findings the pathophysiology of Rett syndrome could be explained by the early and progressive lesions in the brain stem nuclei, which influence the maturation and function of particular parts of the higher central nervous system. Serotonergic and catecholaminergic neurons might have important roles in the pathophysiology of this syndrome. However, biochemical and histochemical examinations of the brain are necessary for detecting the pathogenesis and etiology. And the cause of gynecopathy also remains to be clarified.

Ammonia↗
PubMed1984

Increased muscle action potentials by 5 Hz prolonged nerve stimulation in neurological and neuromuscular disorders--clinical usefulness for detecting underlying pathophysiology.

The time courses of changes in amplitudes of muscle action potentials (MAPs) obtained from gastrocnemius and soleus muscles by 5 Hz prolonged tibial nerve stimulation were studied. Subjects included muscular dystrophy (MD), spinal muscular atrophy, Issacs syndrome, idiopathic muscle spasms, psychiatric disorders such as autism and schizophrenia, and normal controls. In normal subjects, MAPs obtained at 5 minutes from gastrocnemius muscles was 87-102% of those at initiation of the stimulation. In soleus muscles, MAPs at 5 minutes was 95-105% of those at the beginning. In gastrocnemius muscles, MAPs increased in disorders such as Duchenne MD, Fukuyama type congenital MD, facioscapulohumeral MD, myotonic dystrophy, dermatomyositis, Kugelberg-Welander syndrome, viral myelitis, malignant hyperpyrexia, autism and schizophrenia. In soleus muscles, the increase of MAPs was demonstrated in Duchenne MD, Fukuyama type congenital MD, myotonic dystrophy and autism. MAPs remained within normal range in infants with Werdnig-Hoffman disease, Issacs syndrome and idiopathic muscle spasms. In two cases with Duchenne MD, MAPs obtained from gastrocnemius muscles reduced in amplitudes by the administration of dantrolen sodium. While the pathogenesis of the increased MAPs is not clear, several possible factors are discussed. It is considered that this 5 Hz examination may provide an important information for detecting the effect of dantrolen sodium on Duchenne MD, and it is also suggested that the examination will be a useful test for finding latent malignant hyperpyrexia.

Action Potentials↗
PubMed1984

[Body movements during sleep in Lennox syndrome].

In Lennox syndrome the brainstem which plays important roles in regulating sleep and its parameters is thought to be disturbed. In order to clarify the importance of the dysfunction of the brainstem in Lennox syndrome, polygraphic examination were studied and their findings were assessed with prognosis. 8 patients aged from 6 to 17 years were subjected to this study. They were divided into two groups according to their prognosis. Group 1 showed good prognosis. Seizures were easily controllable and have not occurred for more than 24 months. In group 2 seizures were intractable and were uncontrollable by medication. In 4 normal children ranging in age from 4 to 10 years, the same studies were performed. Recordings were performed on two consecutive nights and the second night recordings were used for analysis. Polygraph consisted of EEG from C4 and P4, bipolar EOG from electrode attached to outer canthus, surface EMG from submental muscle and 5 or 6 other muscles including trunk and limbs. Sleep stages were determined in each minute according to the standard of APSS. Body movements were classified into two types on the basis of their distribution over body parts and on duration of movements. Gross movements (GM) involved the body trunk and lasted for more than two seconds. Twitch movements (TM) were localized in one muscle on surface EMG recordings lasting less than 0.5 seconds. In normal children, the rate of GM in sleep stage 1 and REM are significantly higher than slow wave sleep. And this is the same in TM of all muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1982

[Clinical evaluation of cefotiam in internal medicine].

Cefotiam (CTM) was administered to 52 patients with infectious disease associated with respiratory system, hematological malignancy, urinary system and other system. Good clinical responses were obtained in 38 out of 52 cases (73.1%). Neither objective and subjective side effects nor extreme abnormalities of laboratory tests were observed in these patients. It can be, therefore, concluded that CTM is 1 of the most useful drugs for infectious diseases in respiratory system, hematological malignancy, urinary system and other system.

Adolescent↗
PubMed1981

Studies of body movements during night sleep in infancy.

Body movements (BMs) during night sleep of 25 neurologically normal infants, 11 premature and 14 full-term, whose ages ranged from 30 conceptional weeks to 18 months post-term, were examined to evaluate the changes of their features with age. The examinations performed during sleep periods totaled 65 times, 1 to 60 times on each subject. Through visual observation and EEG recordings, the BMs were classified into 3 types: (1) Gross movements (GM), (2) localized movements (LM), both of the above two lasting more than 0.5 second, and (3) twitch movements (TM) lasting less than 0.5 second. Total GM and LM time per hour of sleep, average duration of GM and LM and number of GM, LM and TM per hour of sleep were calculated. Percentage of 20 seconds epochs without BMs (nonbody-movement-epochs) was also estimated. These BMs parameters decreased with maturation to certain low base levels. However, each parameter showed a particular time course. TM decreased initially, then LM and lastly GM reached the base level around the age of 9 to 13 months. On the other hand, nonbody movement-epochs increased progressively until 8 months of age. These three types of BMs are considered to be controlled by the CNS with different organization levels, the simplest for TM and the most complicated for GM. They are thus correlated to the maturational process of the CNS, and could be good indicators for detecting normal and abnormal CNS developments.

Age Factors↗
PubMed1981

Phasing of nucleosomes in SV40 chromatin reconstituted in vitro.

Phasing of nucleosomes on SV40 DNA was studied by the reconstitution of chromatin from SV40 DNA form I and core histones. The reconstituted chromatin sedimented with increasing S values as the histone : DNA ratios increased, and the buoyant densities in CsCl decreased concomitantly. The average repeat lengths of nucleosomes in the chromatin reconstituted at ratios of 1.0 and 1.5 were estimated to be 168 and 143 base pairs, respectively, by electrophoretic analysis of DNA fragments generated by micrococcal nuclease digestion. The chromatin generated a series of DNA bands that differed in size by about 10 nucleotides upon DNase I digestion followed by heat-denaturation. Phasing of nucleosomes was probed by the use of single-site restriction endonucleases, EcoRI, BamH1, BglI, and HpaII: the latter two cleave DNA at and near the origin of DNA replication and transcription. The form I DNA in the chromatin reconstituted at ratios of 0.5, 1.0, and 1.5 was cleaved up to 60 to 80%, 20 to 60%, and 0 to 10%, respectively. Although the frequency of cleavage by these enzymes was not very different at the ratio 0.5, the BglI site became relatively more susceptible than the other sites at the ratio 1.0. At the ratio 1.5, the DNA was almost resistant to these enzymes, though a significant amount (10%) was cleaved by BglI. These results suggest that the origin is the site unfavorable for nucleosome phasing although the region can be almost completely covered with nucleosomes at higher histone : DNA ratios. The fraction of chromatin immunoprecipitated with anti-T serum after in vitro T antigen binding also decreased with increase in the histone : DNA ratios. The results suggest that T antigen binds preferentially to the internucleosomal region. T antigen preferentially bound to the chromatin reconstituted with the DNA fragment containing the origin. Inefficient phasing of nucleosomes at the origin of DNA replication may facilitate the binding of T antigen to the origin.

Antigens, Neoplasm↗
PubMed1980

Association of simian virus 40 T antigen with replicating nucleoprotein complexes of simian virus 40.

An immunoprecipitation assay was established for simian virus 40 T-antigen-bound nucleoprotein complexes by means of precipitation with sera from hamsters bearing simian virus 40-induced tumors. About 80% of simian virus 40 replicating nucleoprotein complexes in various stages of replication were immunoprecipitated. In contrast, less than 21% of mature nucleoprotein complexes were immunoprecipitated. Pulse-chase experiments showed that T antigen was lost from most of the nucleoprotein complexes concurrently with completion of DNA replication. T antigen induced by dl-940, a mutant with a deletion in the region coding for small T antigen, was also associated with most of the replicating nucleoprotein complexes. Once bound with replicating nucleoprotein complexes at the permissive temperature, thermolabile T antigen induced by tsA900 remained associated with the complexes during elongation of the replicating DNA chain at the restrictive temperature. These results suggest that simian virus 40 T antigen (probably large T antigen) associates with nucleoprotein complexes at or before initiation of DNA replication and that the majority of the T antigen dissociates from the nucleoprotein complexes simultaneously with completion of DNA replication.

Antigens, Neoplasm↗
PubMed1979

Gilles de la Tourette syndrome in Oriental children.

Seventy-four cases of tic syndromes were classified into four groups: chronic multiple tics, subacute multiple tics, chronic simple tics and transient simple tics, and 37 cases of chronic multiple tics (Tourette syndrome) were investigated. Clinical evaluation suggested that a transition existed between the four groups. Posture abnormalities were found in 27% of Tourette syndrome and a relation to dystonia was implied. Clinical evaluation and studies of catecholamine blockers' effectiveness suggested the validity of subtyping Tourette syndrome into four groups whose topographical or biochemical abnormalities differ. It was argued that the neurochemical basis of Tourette syndrome might lie in a multiplicity of biochemical abnormalities including disturbances of dopaminergic and noradrenergic pathways.

Adolescent↗
PubMed1979

Fukuyama type congenital muscular dystrophy as a natural model of childhood epilepsy.

Fukuyama type Congenital Muscular Dystrophy, inherited autosomal-recessively, is characterized by muscular dystrophy associated with severe mental retardation and epileptic convulsions. By examining 56 cases, followed for more than three years, 75 EEG records from 40 patients and visual evoked potentials from 11 patients with reference to autopsied materials, the authors aimed at clarifying the causative relationship between congenital central nervous system (CNS) lesions and childhood epilepsy. In 36 out of 56 cases diffuse epileptic seizures were observed with onset at 1.64 +/- 1.01 years average. In 32/36 cases seizures developed before 3 years of age. In 51/75 EEGs focal paroxysmal discharges (FPD), fronto-contro-parietal in younger and centro-occipital in older cases, were observed. Abnormal basic activities (ABA), diffuse-alpha-activity and/or abundant or extreme spindles, were observed more often in older than younger cases. The incidence of FPD was similar between convulsive and non-convulsive cases, but ABA predominated in the former, VEP revealed abnormal findings in 64% of 11 cases examined. Of the CNS pathology, consisting of cerebral and cerebellar gyral abnormalities and a hypoplastic corticospinal tract, the gyral lesions (verrucous polymicrogyria with adhesions of adjacent gyri and cellular disarrangement) were thought to be lesions causing epilepsy. Cortical nonprogressive gyral lesions occurring around the second trimester could cause FPD and clinical diffuse epileptic seizures develop with other factors concerned with ABA.

Brain Damage, Chronic↗