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Biomedical subjects

T Asano

Publications and source records attributed to T Asano.

At least 865 records · Page 48Linked to original sources
PubMed1981

Clinical experience with nasolabial flaps.

The nasolabial flap was used for reconstruction of the nose, lip, and cheek in 23 patients with satisfactory results. From the standpoint of color and texture match, this flap was of considerable value for skin repair of the nose. As for the donor site, the limitation of the nasolabial flap is considered to be about 3 x 10 cm. The nasolabial flap is also discussed from the point of view of recent considerations on its special characteristics and applications.

Adolescent↗
PubMed1981

Sensitivity to ultraviolet light of tobacco mosaic virus modified by cetyltrimethylammonium bromide.

Cetyltrimethylammonium bromide (CTAB) modified tobacco mosaic virus (TMV) virions so that the intrinsic fluorescence changed, viral infectivity decreased, sensitivity to RNase or UV irradiation increased, and coat protein subunits were released by the addition of Triton X-100. The change in fluorescence emission at 320 nm shifted to 340 nm was observed at 100 micrograms of CTAB per ml. This represents a change in the tryptophan environment inside the virion. At a lower concentration of CTAB, intersubunit contact was weakened, resulting in the release of coat protein subunits and an increase in RNase sensitivity. The release of coat protein took place gradually and two relatively stable intermediates were observed. Increase in UV sensitivity was observed at a lower concentration of CTAB and formation of pyrimidine hydrate was involved in this inactivation. The nature of the minor structural change leading to UV inactivation is discussed.

Capsid↗
PubMed1981

Cerebral protective effect and radical scavenging action.

The role of radical scavenging action in cerebral protective effect of drugs was investigated in vitro. Incubation of rat brain mitochondrial suspension with ascorbic acid and Fe2+ resulted in the formation of malondialdehyde and a decrease in the turbidity of the suspension, indicating that the mitochondria were peroxidatively disintegrated. Nizofenone at 10 micro M or more inhibited the peroxidative disintegration of mitochondria, and complete inhibition was observed at 100-200 micro M. The action of nizofenone was also ascertained by experiments with rat liver mitochondria. The anti-peroxidative activity of nizofenone was estimated to be approximately equivalent to that of alpha-tocopherol, and this property was unique. Among the cerebral protective drugs tested, thiopental was only slightly efficient, and pentobarbital, phenobarbital, and dimethyl sulfoxide had no effect. In addition, nizofenone was found to scavenge a stable free radical, diphenyl-p-picrylhydrazyl, but the barbiturates did not. These findings suggest that there is no intimate relationship between cerebral protective effect and free radical scavenging action.

Animals↗
PubMed1981

Effects of hypoxia and metabolic inhibitors on the electrical and mechanical activities of isolated guinea pig papillary muscles.

Electrical and mechanical activities of the isolated guinea pig papillary muscle were measured simultaneously, and the effects of various degrees of hypoxia and metabolic inhibitors were examined. Hypoxia selectively diminished the action potential duration (APD) dependently upon the degree of hypoxia with little affecting the other parameters of the action potential. Hypoxia concomitantly depressed the contractile force (CF), but the decrease in CF always preceded the decrease in APD; thus, the complete excitation-contraction uncoupling was sometimes observed. Metabolic inhibitors (dinitrophenol, DNP and monoiodoacetic acid, IAA) produced qualitatively the same changes in the electrical and mechanical activities. However, DNP mimicked hypoxia better than IAA which produced rather parallel decreases in CF and APD. The slow response action potential (elicited after inactivation of the excitatory fast Na system of the membrane) was completely blocked by hypoxia and metabolic inhibitors, which was partially restored by isoproterenol, histamine and tetraethylammonium. When isoproterenol was present in the bathing solution, the decreases in CF and APD produced by hypoxia were accelerated, but ATP and propranolol did not significantly modify the hypoxically induced changes.

2,4-Dinitrophenol↗
PubMed1981

A rapid method for the separation of rat pancreatic islets from collagenase-digested pancreas using Percoll.

The isolation of pancreatic islets from collagenase-digested Wistar rat pancreas was shown by the sedimentation method at a unit gravity using Percoll solution with a density of 1.041 g/ml. The density of digested exocrine tissues was in the range of 1.013-1.041 g/ml, while that of purely isolated islets was in the narrow range of 1.066-1.075 g/ml. More than a hundred islets were obtained freely from each rat pancreas without any gross contamination of digested exocrine tissues. A significant increase was observed in glucose-stimulated insulin release from islet isolated with Percoll in the same pattern as that without Percoll. In addition to the well preserved morphology and function of pancreatic islets isolated by Percoll, the simplicity of the technique strongly commends the usefullness of this method.

Animals↗
PubMed1981

Hypotensive response to angiotensin II analogue and angiotensin I converting enzyme inhibitor in pseudo-Bartter's syndrome.

We studied the effect of angiotensin II analogue (AII-A) and angiotensin I converting enzyme inhibitor (SQ 14,225) on blood pressure and the renin-angiotensin-aldosterone system in a patient with pseudo-Bartter's syndrome, who was a 26-year-old unmarried Japanese woman taking furosemide surreptitiously. The intravenous infusion of AII-A decreased blood pressure from 85/35 to 68/28 mmHg. This decrease in blood pressure was associated with an increment of plasma renin activity (PRA) and a decrement of plasma aldosterone concentration (PAC). Similarly, SQ 14,225 given orally decreased blood pressure to the same extent. An increment of PRA and a decrement of PAC were also observed. These results suggest that the renin-angiotensin system plays a considerable role in maintaining blood pressure in pseudo-Bartter's syndrome. Again, attention has to be paid to the possibility of surreptitious use of diuretics in an adult patient with persistent hypokalemic alkalosis, hyperactivity of the renin-angiotensin-aldosterone system and angiotensin II insensitivity simulating "true" Bartter's syndrome.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1981

Polymorphism of serum protein in guinea pigs of inbred strains.

Three fractions of prealbumin tentatively designated as PA I, II and III were separated by starch gel electrophoresis of sera of inbred guinea pig strains 2 and 13. Migration of PA II in strain 13 was faster than that in strain 2. PA II in F1 hybrid between strains 2 and 13 showed a single broad band approximately twice the width of each strain. Migrations of PA II in other 10 inbred strains of JY series were the same as that of strain 2, except for one strain, JY-8, which showed the same pattern as in strain 13. Thus the PA II migration seemed to be of codominant inheritance and a useful biochemical marker for identification of inbred strains of guinea pigs.

Animals↗
PubMed1981

A double antibody radioimmunoassay for measurement of IgG, IgA and IgM synthesized by human lymphocytes in vitro.

To investigate cellular interactions between human T and B lymphocytes in various diseases, we established a technique to prove terminal differentiation of B lymphocytes into immunoglobulin synthesizing and secreting cells. We also established a double antibody radioimmunoassay to measure the amount of IgG, IgA and IgM synthesized and secreted in culture supernatants. Purified immunoglobulins were obtained from sera of patients with myeloma or macroglobulinemia. The peripheral blood lymphocytes from 25 normal individuals had the geometric mean synthetic rates of 1886 ng for IgG, 1607 ng for IgA and 1173 ng for IgM per 1 X 10(6) cells when cultured for nine days in the presence of pokeweed mitogen. The method is simple and sensitive, and is thought to be useful for examining human lymphocyte function in vitro.

Cells, Cultured↗
PubMed1981

The effect of a lipid hydroperoxide of arachidonic acid on the canine basilar artery. An experimental study on cerebral vasospasm.

The in vivo spasmogenic capacity of a lipid hydroperoxide (15-hydroperoxy arachidonic acid: 15-HPAA) was studied in a chronic experiment using the dog. The 15-HPAA was injected into the cisterna magna (0.2 or 2 mg emulsified in bovine serum albumin solution). The changes in diameter of the basilar artery were followed by angiography, and the morphological changes were studied by electron microscopy. The cisternal injection of 0.2 mg of 15-HPAA caused a mild constriction of the basilar artery which lasted about 7 hours. The cisternal injection of 2 mg of 15-HPAA caused a biphasic constriction, the initial phase of which was a moderate narrowing lasting about 10 hours. The second phase started on the 2nd or the 3rd day after injection. The intensity of the arterial narrowing was more pronounced in the second phase than in the first. The prolonged secondary constriction of the basilar artery continued until sacrifice on the 7th day after injection. Electron microscopic study revealed a marked degenerative change in the endothelium and myonecrotic changes in the tunica media. The prolonged arterial constriction in the second phase was invariably associated with remarkable degeneration of the endothelium. On the other hand, myonecrotic changes were limited to a small number of smooth-muscle cells. The results of the present study are consonant with the hypothesis that lipid peroxidation associated with lysis of the subarachnoid clot is involved in the genesis of chronic vasospasm in subarachnoid hemorrhage.

Animals↗
PubMed1981

Evaluation of prostaglandin biosynthetic activity in canine basilar artery following subarachnoid injection of blood.

Transformation of arachidonic acid into prostaglandins was investigated in the basilar artery by incubating sections of artery with carbon-14-labeled arachidonic acid. Thin-layer radiochromatography revealed that, in normal canine basilar arteries, 14C-arachidonic acid was transformed mainly to 6-keto-prostaglandin (PG)F1 alpha, a spontaneous metabolite of prostacyclin (PGI2). Among other prostaglandins, only a small amount of PGF2 alpha was detected, whereas PGD2, PGE2, and thromboxane B2 were not. Arteries removed on Days 3 and 8 after subarachnoid blood injection showed a prostaglandin synthesis profile similar to that in the normal cerebral artery. In borate-buffered saline (0.1M borate buffer, pH 9.0/0.15M NaCl = 1:9, vol/vol), canine basilar artery produced a PGI2-like substance that inhibited adenosine diphosphate (ADP)-induced platelet aggregation. Its anti-aggregatory activity was completely abolished by acidification. Aspirin likewise inhibited production of the anti-aggregatory substance. From these results, it was concluded that the anti-aggregatory activity was due solely to the production of PGI2 by the arterial specimen. Based on the above results, PGI2 biosynthetic activity in the cerebral artery exposed to subarachnoid blood injection was bioassayed by measuring the inhibitory activity of the incubation product upon ADP-induced platelet aggregation following incubation of the arteries in borate-buffered saline for 5 to 30 minutes at 20 degrees C, using synthetic PGI2-Na as a standard. The synthetic activity of PGI2 in the artery exposed to subarachnoid blood injection had diminished remarkably by Days 3 and 8. This diminution of PGI2 synthesis in the cerebral artery may be involved in the pathogenesis of cerebral vasospasm.

Animals↗
PubMed1981

Asymmetric division of lymphoid cells of the thymus of embryonic guinea-pigs. A cell kinetic study.

Cell division of thymus lymphoid cells from 30- to 60-day-old embryonic guinea-pigs, as well as young adults was investigated on cell smears stained with Giemsa. Asymmetrically dividing cells were found in the developmental stage of thymocytes. At the telophase of such cells, the cytoplasma of one of two immature daughter cells was apparently larger in amount than that of the counterpart cell. When 40-day embryonic lymphoid cells were examined, most of the asymmetrically dividing cells at telophase belonged to the larger cell population (mean diameter 15.7 micrometer). The mean diameters of the larger and smaller immature daughter cells of these dividing cells were estimated as 12.0 and 9.2 micrometer, respectively. Ultrastructural study also revealed a lymphoid cell which was under-going in situ apparent symmetric division at telophase. One of two immature daughter cells alone possessed a large cytoplasmic protrusion with few organella. The frequence of asymmetric division calculated by a rough estimation was around 10% of the total cell division between days 30 and 40 of embryonic development, and decreased thereafter. During this developmental period, thymic lymphoid cells were shown to progressively transform into smaller cells. A scheme regarding the mode of thymocyte proliferation during the embryonic period is proposed. and the biological meaning of the present phenomenon is discussed.

Animals↗
PubMed1981

Prevention of gastric ulcers in swine by feeding of sodium polyacrylate.

Five experiments involving 169 swine were conducted to determine the effects of 0.1% to 0.5% sodium polyacrylate (PANa) in rations of growing swine on weight gain, feed conversion, and occurrence of esophagogastric lesions. Seemingly, PANa prevented swine from developing esophagogastric ulcers. Esophagogastric ulcers or erosions occurred in 42.9% of the swine fed a PANa-free diet, but occurred in only 9.8% of those fed a diet containing PANa. Addition of PANa (0.1% to 0.5%) to the growing ration increased weight gain and feed conversion. The anti-ulcer effect of PANa was discussed.

Acrylic Resins↗