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Biomedical subjects

Y Matsubara

Publications and source records attributed to Y Matsubara.

At least 289 records · Page 16Linked to original sources
PubMed1985

Stable isotope study of plasma taurine kinetics in rhesus monkey.

Taurine is one of the most abundant amino acids in mammals and there is increasing evidence for the importance of taurine during development. Plasma taurine kinetics in a rhesus monkey was studied using [1,2-13C2]taurine. Taurine in plasma was derivatized to its dimethylaminomethylene methyl ester, separated on a gas chromatographic column, and the [M+2+H]+/[M+H]+ ion ratio was measured by ammonia chemical ionization mass spectrometry. The results were comparable to those obtained from the simultaneous radioisotope tracer study using [35S]taurine. This stable isotope method requires only 200 microliters of plasma for precise and accurate determination and is suitable for taurine kinetic studies in human infants.

Animals↗
PubMed1985

Self-excitation in a porous membrane doped with sorbitan monooleate (Span-80) induced by an Na+/K+ concentration gradient.

The electrical potential across a fine-pore membrane doped with sorbitan monooleate (Span-80) imposed between aqueous solutions of NaCl and KCl was studied. It was found that this system showed rhythmic and sustained oscillations of electrical potential between the two aqueous solutions. These oscillations were attributed to the change of permeability of Na+ and K+ across the membrane, which originated from the phase transition of Span-80 molecules within the fine pores. Impedance measurement across the membrane also suggested a change in permeability. It was found that this membrane exhibited the property of differential negative resistance. In relation to this, it was shown that Na+ and K+ have different effects on the aggregation of Span-80 molecules. The mechanism of oscillation is discussed in relation to the ability of Span-80 molecules to behave as a dynamic channel through the membrane. This oscillatory phenomenon is interesting because in biological nervous membranes a difference between the concentrations of Na+ and K+ across the membranes is essential for excitability.

Hexoses↗
PubMed1985

Biopterin and neopterin in various milks and infant formulas.

Biopterin and neopterin concentrations were measured by reverse-phase high pressure liquid chromatography in milks of man, cow, rabbit, cat, and rat and in commercial formulas widely used in North America. There was wide variation of concentration among species. Higher concentrations of biopterin were present in human milk (392.0 +/- 158.6 pmol/ml) than were present in all milk formulas analyzed (2.6-50.6 pmol/ml).

Animals↗
PubMed1985

[Teratogenic potentially of single dose of thalidomide in JW-NIBS rabbits].

A single dose (500 mg/kg) of thalidomide was administered orally to pregnant JW-NIBS rabbits in various stages of organogenesis. Head anomalies in fetuses (anencephaly, holoprosencephaly and hydrocephaly) were induced at a high frequency by the maternal administration of thalidomide on day 7, and also in a few fetuses on day 8. These fetuses included those with an abnormal skull such as hypoplasia of cerebral and facial skull. Microphthalmia in fetuses was observed with a single administration from day 7 to 12 of gestation. Contracture of forearms and club foot in fetuses resulted from the maternal administration of thalidomide on day 8 or 9 of gestation, respectively. With a single administration on day 8 or 9 of gestation, kinky tail in fetuses resulted, and brachyury was observed with a high frequency from day 8 to 11 of gestation. Skeletal anomalies such as fusion or displacement of coccygeal vertebral bodies were observed at a high frequency with a single treatment from day 8 to 10 of gestation. Among the internal anomalies observed was abnormal lobation of the lung, resulting from a single treatment from day 6 to 15 of gestation (except for day 13), and abnormal lobation of the liver, induced from day 7 to 10. The cardiovascular anomalies were induced at a high frequency with a single treatment from day 7 to 9 of gestation. In the present experiment, the critical period for each anomaly produced by thalidomide in JW-NIBS rabbits was determined.

Abnormalities, Drug-Induced↗
PubMed1985

Encephalitis induced in non-human primates by canine distemper virus adapted to human neural cells.

The Onderstepoort strain of canine distemper virus (CDV) adapted to human oligodendroglioma, neuroblastoma and glioblastoma cells, was intracerebrally inoculated into cynomolgus monkeys. All the three viruses caused periventricular encephalitis involving the brain stem. When the neurovirulence of these viruses were compared in terms of clinical signs and histopathological changes, the oligodendroglioma-adapted virus showed the neurovirulence of the highest degree inducing degeneration of axons and glial cells. Chronic encephalitis was also observed. The neuroblastoma-adapted virus induced predominantly nerve-cell degeneration although clinically this virus showed slightly lower degree of neurovirulence than the oligodendroglioma-adapted viruses. The glioblastoma-adapted virus showed clinically much lower neurovirulence than the other two viruses; all monkeys infected with this virus survived and produced high level of antibody in most cases. Histopathologically degeneration of axons and glial cells was characteristics although the incidence was less frequent than the oligodendroglioma-adapted virus. Predominant involvement of nerve cells by neuroblastoma-adapted virus and predominant involvement of axon and glial cells by oligodendroglioma-adapted virus and by glioblastoma-adapted virus suggest that in vitro tropism of the virus to neural cells is partially reflected on tropism of the virus in the CNS.

Animals↗
PubMed1984

Oscillation of electrical potential in a porous-membrane doped with triolein induced by an Na+/K+ concentration gradient.

The electrical potential across a fine pore membrane doped with trioleoyl glyceride (triolein) and separating aqueous solutions of 0.5M NaCl and 0.5M KCl, respectively, was studied. It was found that this system showed rhythmic and sustained oscillations of electrical potential between the two aqueous solutions. These oscillations were attributed to the change of permeability of Na+ and K+ ions across the membrane, which originated from the phase-transition of triolein molecules within the fine pores.

Mathematics↗
PubMed1984

Oscillation of electrical potential in a porous membrane doped with glycerol alpha-monooleate induced by an Na+/K+ concentration gradient.

The electrical potential across a fine-pore membrane doped with glycerol alpha-monooleate and separating aqueous solutions of 0.5 M NaCl and 0.5 M KCl was studied. It was found that this system showed rhythmic and sustained oscillations of electrical potential. These oscillations may be due to the phase transition of glycerol alpha-monooleate molecules within the fine pores. In relation to this, it is shown here that Na+ and K+ have different effects on the aggregation of glycerol alpha-monooleate. This oscillatory phenomenon is very interesting because in biological nervous membrane an Na+/K+ concentration difference across the membrane is essential for excitability.

Glycerides↗
PubMed1984

Spontaneous malformations in JW-NIBS rabbits.

The frequency of spontaneous anomalies among JW-NIBS rabbits in our laboratory is reported. The study was based on 1217 live fetuses obtained from 185 of an origin sample of 195 pregnant females; the remaining 10 (5.1%) aborted. Seven (0.57%) of the fetuses had the following external anomalies: multiple anomalies with craniofacial anomalies and thoraco-, gastroschisis (3 cases), microcephaly with open eyelids and microstomia (1), microphthalmia (1), anury (1) and brachyury (1). Among 1213 fetuses, 2 (0.16%) had abdominal visceral anomalies: agenesis of gall bladder and hypoplasia of the ovary were each found in one animal. Head and thoracic visceral anomalies were found in 6 (1.73%) of 347 fetuses, and skeletal anomalies in 6 (0.69%) of 867 fetuses. 4.03% of fetuses had 13 ribs.

Abnormalities, Multiple↗
PubMed1984

A randomized clinical trial of adjuvant chemotherapy after resection in patients with stomach cancer.

A study group including 55 institutions in Japan evaluated the effect of adjuvant cyclophosphamide therapy on 461 patients who had undergone curative resection for stomach cancer. Patients, who were followed up for over three years, were randomly divided into three groups: curative resection and long-term drug therapy; curative resection and short-term drug therapy; and curative resection and no drug therapy. Long-term therapy consisted of (a) twice-weekly intravenous doses of 500 mg of cyclophosphamide for four weeks and, after five weeks with no medication, (b) 100 mg/day, given orally, for 40 days and, after ten weeks with no medication, (c) 100 mg/day, given orally, for 40 days. Short-term therapy consisted of only the first course of therapy (ie, twice-weekly intravenous doses of 500 mg for four weeks). The effect of cyclophosphamide differed, depending on the patients' levels of serosal and lymph node invasion: Short-term therapy was more effective in patients with lymph node involvement, and long-term therapy was more effective in patients with serosal involvement.

Clinical Trials as Topic↗