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Biomedical subjects

M Matsuda

Publications and source records attributed to M Matsuda.

At least 1,261 records · Page 70Linked to original sources
PubMed1984

[Subdural tension pneumocephalus after trephination for chronic subdural hematoma].

Symptomatic tension pneumocephalus developed after an evacuation of chronic subdural hematoma is reported. In this 71 year-old man, a rapid deterioration of consciousness was noted 5 days after a trephination for bilateral chronic subdural hematomas. An evacuation of hematoma was performed under a local anesthesia, and the preoperative and immediate postoperative course was uneventful. Subdural tension pneumocephalus was confirmed by typical CT findings and treated by re-trephination and drainage. The literature on the tension subdural pneumocephalus was reviewed, and the mechanism of its development was briefly discussed.

Aged↗
PubMed1983

Tetanus toxin: a rapid and selective blockade of the calcium, but not sodium, component of action potentials in cultured neuroblastoma N1E-115 cells.

The slow action potential of mouse neuroblastoma N1E-115 cells, which was elicited in Na-free medium and whose amplitude was directly dependent on extracellular Ca concentrations, was blocked by tetanus toxin (TNTX) without change in resting membrane potential and resistance. The average value of action potential overshoot (peak potential level of spikes) in the absence and presence of TNTX was -1 and -11 mV, respectively. The concentration of TNTX required for 50% inhibition of Ca-dependent spikes (IC50) was about 65 ng/ml. The amplitude of spikes was decreased within 10-20 min after adding TNTX. The inhibition of Ca-dependent spikes was mimicked by 10 mM CoCl2 and MnCl2, but not by the boiled or neutralized toxin. The results indicate that TNTX inhibited electrogenesis of Ca, but not Na, components of action potentials of the neuroblastoma cells.

Animals↗
PubMed1983

Tetanus toxin blocks Ca spikes in neuroblastoma clone N1E-115 cells.

The effect of tetanus toxin on the Ca spike of the action potential evoked in neuroblastoma clone N1E-115 cells by constant current stimulation in Na+-free medium containing various concentrations of Ca2+(1.8-80 mM) was examined by intracellular recordings. Tetanus toxin (more than 140 ng/ml) blocked the Ca spikes. The resting membrane potentials and membrane input resistances of tetanus toxin-treated cells were similar to those of untreated cells. The blocking effect of tetanus toxin was evident in medium containing Ca2+ at concentrations of more than 30 mM. The difference between the peak levels of the action potentials of toxin-treated and untreated cells was statistically significant at Ca2+ concentrations of 7.2 mM and more.

Action Potentials↗
PubMed1983

Cytogenetic analysis of recombination in males of Drosophila ananassae.

Cytogenetic studies of recombination in males of Drosophila ananassae were carried out by examining F1 males derived from he mating of marker females, b se; bri ru of the BS stock, with males of two wild strans, TNG and L8. The male recombination values in both sections b-se (chromosome 2) and bri-ru (chromosome 3) are high in TNG F1 but extremely low in L8 F1. We demonstrate the presence of chiasmata in TNG F1 males at a frequency capable of accounting for the observed recombination values. A unique series of "iso-site aberrations" was also observed in TNG F1 males. Because of a parallelism in the distribution pattern between the chiasmata and the iso-site aberrations, we propose that recombination in males of D. ananassae is meiotic in origin and that the iso-site aberrations are related to chiasma formation.

Animals↗
PubMed1983

On the existence of two GABA pools associated with newly synthesized GABA and with newly taken up GABA in nerve terminals.

[14C]Glutamic acid and [3H]GABA were injected into the lateral ventricle of mouse and then [14C]GABA and [3H]GABA in synaptosomes isolated from the animals were analysed. The [14C]GABA was interpreted to be newly synthesized GABA from [14C]glutamic acid while the [3H]GABA to be newly taken up GABA. We have obtained the following results: (1) when the animals were pretreated with aminooxyacetic acid and thus the GABA content in synaptosomes increased to about 2 times of the control level, only the [3H]GABA was enhanced to 3 times of the control level without any change of [14C]GABA, (2) the release of [14C]GABA from synaptosomes by high K+ depolarization was 1.5 times greater than that of [3H]GABA, (3) the releases of both [14C]GABA and [3H]GABA were increased in the presence of cold GABA, L-2,4-diaminobutyric acid or gamma-amino-beta-hydroxybutyric acid, but only slightly increased in the presence of beta-alanine. These results would suggest that newly synthesized GABA and newly taken up GABA localized individually in different pools, which might localize either in different nerve terminals or separately in the same nerve terminal.

Amino Acids↗
PubMed1983

Dissociation between regional myocardial dysfunction and ECG changes during myocardial ischemia induced by exercise in patients with angina pectoris.

In order to investigate the relation between regional myocardial function and electrical changes during myocardial ischemia in humans, left ventricular echocardiogram and ECG were recorded during supine ergometer exercise in 16 patients with coronary artery disease until angina or ischemic ECG appeared. During exercise in 13 patients a decrease of left ventricular posterior wall excursion or of interventricular septum excursion occurred earlier than the appearance of ST-T change on ECG. In two patients the excursion decreased at the same time as the ST-T change. Significant regional myocardial dysfunction occurred at 30 +/- 15 seconds and ECG changes occurred at 90 +/- 60 seconds (p less than 0.001). Percent systolic wall thickening occurred in similar fashion. Results support the hypothesis that regional contractile abnormalities may provide a more sensitive indicator of myocardial ischemia than ST-T changes in humans.

Aged↗
PubMed1983

Myocardial mechanics of athletic hearts in comparison with diseased hearts.

Parameters of myocardial mechanics were measured by means of echocardiography in 31 competitive runners and 17 judo (Japanese wrestling) champions and were then compared with those in 25 normal control subjects, 15 patients with volume-overloaded (aortic regurgitation, AR) and 13 with pressure-overloaded (hypertension, HT) hearts, 14 patients with dilated cardiomyopathy (DCM), and 11 patients with hypertrophic cardiomyopathy (HCM). In runners, the ratio of left ventricular radius to wall thickness (R/Th) was maintained in the normal range, but fractional shortening (FS) and decreased slightly (p less than 0.01). Patients with decompensated DCM and AR had an increased R/Th (p less than 0.001) and a decreased FS (p less than 0.001). In judo champions, FS was maintained in the normal range, but R/Th had decreased (p less than 0.001). In patients with HT, R/Th had decreased slightly (p less than 0.05), but FS and peak systolic wall stress were maintained in the normal range. In patients with HCM, FS was maintained in the normal range, but R/Th had decreased (p less than 0.001). It is concluded that, at rest, hearts of runners are cardiomechanically similar to those of patients with compensated AR or DCM and probably have greater cardiac reserve, whereas hearts of judo champions are similar to those of HCM patients with inappropriate hypertrophy.

Adolescent↗
PubMed1983

Studies on the development of melanophores in in vitro cultured amphibian neural plates.

Various parts of neural plates of Japanese newt (Cynops pyrrhogaster) neurula embryos were cultured alone in drops of culture media (Niu-Twitty's balanced salt solution or modified Leibovitz L-15 medium) with or without fetal calf serum (FCS). Although none of the parts gave rise to melanophores in a medium without FCS, some produced melanophores in a medium with FCS. The localization of melanophore-producing areas in the neural plates corresponded to that of Tada's (1944) findings. The assumption that FCS affects survival and development of melanophores is excluded, because neural fold cells do not require FCS to develop into melanophores. Therefore, there may be in FCS some factor which acts on the specialization of neural plate cells into melanophores. The results of this experiment suggest that this factor may be heat labile. The findings also indicate that FCS does not induce melanophores in gastrula ectoderm, but only affects neurula neural plate cells so as to give rise to melanophores.

Animals↗
PubMed1983

Ruptured cerebral aneurysms associated with arterial occlusion.

Seven cases of ruptured cerebral aneurysm associated with an occlusion of a large cerebral artery are reported. All seven patients had never suffered from ischemic cerebrovascular disease before the aneurysmal rupture. All nine aneurysms, including the two unruptured ones, arose on the artery serving as an important collateral pathway, and eight of the nine were found in locations where saccular aneurysms are known to occur infrequently. The role of hemodynamic factors in the pathogenesis of these aneurysms is stressed.

Aged↗
PubMed1983

Dynamic computed tomography and functional imaging in cerebral vascular anomalies.

Dynamic computed tomography was performed on patients with cerebral vascular anomalies, the density-versus-time curves were derived, and the gray-scale functional images demonstrating the pixel-by-pixel distribution of several flow parameters were processed. This noninvasive method was found to be useful not only in delineating the vascular anomalies with their afferent and efferent vessels, but also in detecting the abnormal flow patterns within and outside the vascular anomalies. Limitations and distinct advantages of this technique are briefly discussed.

Adolescent↗