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Biomedical subjects

K Shibata

Publications and source records attributed to K Shibata.

At least 667 records · Page 37Linked to original sources
PubMed1985

[The effects of intra-abdominal pressure on regional renal blood flow during peritoneal dialysis].

This experimental studies were designed to investigate the effects of intra-abdominal pressure (IAP) on renal regional blood flow and renal function during peritoneal dialysis (PD) for acute renal failure (ARF). The mongrel dogs were divided into four groups. Group I (n = 10): IAP of atmospheric pressure without PD (control group); Group II (n = 10): Intermittent PD with IAP of 10 mmHg; Group III (n = 10): Intermittent PD with IAP of 20 mmHg; Group IV (n = 10): Continuous PD with IAP of 3-5 mmHg. The following results were obtained. Significant decrease (p less than 0.01-0.05) of renal cortical blood flow (RCBF), total renal blood flow (TRBF), ratio of RCBF to renal medullar blood flow, renal perfusion pressure (RPP), cardiac index and urinary output, and increased renal vascular resistance and inferior vena caval pressure were observed in group III, but in group IV, values of these parameters returned to control level. The limit of influence to renal function was confirmed to be as follows. (1) IAP of 30 mmHg or more, (2) RPP of less than 65 mmHg, (3) TRBF of less than 2.2 ml/g/min, (4) and RCBF of less than 78 ml/100 g/min. These studies suggest that RPP are simple and excellent index to reflex renal hemodynamics, and the continuous PD are better procedure than the intermittent PD from a view of renal regional blood flow.

Abdomen↗
PubMed1984

Comparison of actual survivorship after treatment with survivorship predicted by actual tumor-volume doubling time from tumor diameter at first observation.

The predicted survival time of 56 patients with lung cancer was calculated using Geddes ' nomogram for tumor diameter and tumor doubling time. The predicted survival time correlated favorably with the actual survival time. For many patients with resection the actual survival time far exceeded the predicted survival time; thus, the latter may be very useful as a control for the evaluation of all therapies of lung cancer.

Adenocarcinoma↗
PubMed1984

Distribution of alpha 2-macroglobulin in normal, inflammatory, and tumor tissues in rats.

Distribution of uptake and catabolism of intravenously administered 125I-labeled rat alpha 2-macroglobulin(125I-alpha 2MG) were examined in normal, inflammatory, and tumor tissues of rats. Clearance of intravenously administered [125I]alpha 2MG from the circulation was rapid. Accumulation of this compound into inflammatory tissue was 2-3 times more extensive than in normal tissues. The accumulation into sarcoma tissue was much less. Radioactivity in TCA-PTA precipitates remained fairly constant for the first 12 h in inflammatory tissue and for the first 24 h in sarcoma. These patterns of accumulation were never observed in the normal tissues. As the kidney preferentially accumulated large amounts of [125I]alpha 2MG in the nondegraded form and its degradation products, the tissue may play a special role in the metabolism of alpha 2MG. Rapid clearance from the circulation and relatively small amounts of accumulation in tissues suggest that alpha 2MG may function as a protease inhibitor, mainly in the circulation rather than in the tissues.

Animals↗
PubMed1984

Aminopeptidase and caseinolytic activities of Mycoplasma salivarium.

Aminopeptidase activity was demonstrated in Mycoplasma salivarium (ATCC 23064) cells disrupted by sonic vibrations and lyophilized (crude enzymes), and weak endopeptidase or carboxypeptidase activity was also suggested. The crude enzymes were suspended in 0.1 M borate buffer, pH 8.0, containing 0.5% (w/v) sodium deoxycholate, and then the suspensions were centrifuged at 100,000 g for 2 h. Thus separated, the supernatants were applied to a column of Sephacryl S-300. As a result, aminopeptidase activity was separated from caseinolytic activity, which had already been demonstrated in this organism. The aminopeptidase activity was inhibited by o-phenanthroline and stimulated by Mn2+, and the enzyme exhibited a strong affinity for leucine and arginine. On the other hand, the caseinolytic activity was inhibited considerably by o-phenanthroline and Ni2+ and slightly by diisopropyl fluorophosphate and Co2+. The caseinolytic activity was therefore believed to be due mainly to metalloproteinases and partly to serine proteinases.

Aminopeptidases↗
PubMed1984

Therapeutic effect of cefotetan in an experimental local infection with facultative and obligate anaerobes in granuloma pouches in rats.

The therapeutic activities of cefotetan against experimentally induced infections with Escherichia coli. Serratia marcescens, Bacteroides fragilis or Fusobacterium mortiferum in the granuloma pouches of rats were compared with those of cefmetazole and cefazolin. Of these antibiotics, cefotetan showed the greatest therapeutic effect against the four bacterial infections after a single intramuscular administration. Cefotetan was found to give much higher pouch exudate concentrations than cefmetazole, and to show prolonged antibacterial levels even when compared with cefazolin. In the granuloma pouch, cefotetan produced similar morphological changes in the cells of E. coli NY-17 as have been observed in vitro by microscopy. Elongation and bulge formation were noted.

Animals↗
PubMed1984

Ineffectiveness of Ca2+-antagonists nicardipine and diltiazem on experimental atherosclerosis in cholesterol-fed rabbits.

There is accumulating evidence that calcium metabolism plays an important role in the pathogenesis of atherosclerosis. The inhibitory effect of nifedipine, a Ca2-antagonist, on experimental atherosclerosis in cholesterol-fed rabbits has been reported, and we examined the anti-atherosclerotic action of nicardipine and diltiazem, similar Ca2+-antagonists, but no inhibitory action was observed. It is necessary to recognize the fact that the sensitivity of rabbits to an anti-atherogenic diet shows great individual differences. For the purpose of preventing atherosclerosis due to the abnormality of lipid metabolism the use of Ca2+-antagonist is not warranted at the present stage.

Animals↗
PubMed1984

Screening of sugars inhibitory against sucrose-dependent synthesis and adherence of insoluble glucan and acid production by Streptococcus mutans.

Various sucrose derivatives and a sucrose analogue were enzymatically synthesized on the assumption that structural similarities of the sugars to sucrose would endow them with an ability to inhibit the cariogenicity of sucrose. The effect of these sugars on sucrose-dependent synthesis and adherence of insoluble glucan and on acid fermentation of sucrose by Streptococcus mutans was examined in vitro. Although none of them inhibited the acid fermentation, several sugars not only inhibited the synthesis and adherence of insoluble glucan, but were themselves only slightly fermented as well.

Acids↗
PubMed1984

Behavioral effects of brotizolam, a new thienotriazolodiazepine derivative.

The behavioral effect of brotizolam was investigated in mice and rats, in comparison with those of diazepam, nitrazepam and estazolam. Locomotor activity of rats in an open field situation was slightly increased with smaller doses of brotizolam and estazolam and with larger doses of nitrazepam, while it was decreased with large doses of brotizolam and estazolam. The anticonflict effect of brotizolam in rats was approximately as potent as that of diazepam and was augmented following chronic administration for 10 days. In suppressing hyperemotionality and muricide of olfactory bulbectomized rats, brotizolam was more potent than diazepam, being approximately equipotent to nitrazepam and estazolam. Brotizolam, diazepam, nitrazepam and estazolam prevented both maximal electroshock and pentetrazol convulsions in mice, the effects on the latter being much more potent than those on the former. In impairing rotarod performance, brotizolam was as potent as estazolam and nitrazepam and was much more potent than diazepam in mice, but was less potent than estazolam and nitrazepam in rats. These results indicate that brotizolam possesses pharmacological properties characteristic to benzodiazepines and that the activity is more potent than that of diazepam and approximately as potent as those of nitrazepam and estazolam.

Aggression↗
PubMed1984

Effect of induced hypertension on experimentally-induced cerebral arterial spasm.

Ten adult cats were anesthetized and ventilated by respirator. After the basilar artery was exposed transclivally and visualized with an operative microscope, mean arterial blood pressure (MABP) was raised gradually by intravenous drip infusion of norepinephrine (5-20 micrograms/kg) or angiotensin-II-amide (0.3-1.0 micrograms/kg). At various blood pressures, microphotographs were taken. There was no appreciable change in vessel diameter at a MABP ranging from 78 to 191 mmHg. The blood pressure was allowed to return to the initial baseline level. Arterial spasm was produced by the topical application of 0.2 M calcium gluconate, which decreased the arterial diameter by 13 to 58 percent for more than 60 min. Blood pressure was increased again after the production of the arterial spasm. Significant increases in the diameter of the arteries were produced by the drug-induced hypertension at levels of MABP ranging from 82 to 192 mmHg. The maximum arterial dilations ranged from 123 to 208 percent of the untreated control. The degree of dilation of the arteries almost paralleled the rise in MABP. Norepinephrine and angiotensin-II had a similar effect on both the blood pressure and the arterial diameter. Induced hypertension would be expected to improve blood flow parameters in the case of spastic cerebral arteries.

Angiotensin II↗
PubMed1984

Clinical and nutritional study on gallstone disease in Japan.

The dietary factors, as a cause on increasing incidence of gallstones in Japan, were studied. The increase in the incidence of gallstones at autopsy was nearly paralleled with that of fat intake on a line graph and reversely the carbohydrate intake including crude fiber showed a decreasing trend. In the nutritional survey of patients with gallstone, the fat intake was 22% higher than that of the control group, and the crude fiber intake was 18% lower. Comparing the incidence of cholesterol stones during each 10 years of 1953-1962 and 1969-1980 with the nutritional intake, the incidence of gallstones increased by 25% and the fat intake by 120%, but the carbohydrate intake including crude fiber decreased by 14%. From the above, it was considered that the increase of the incidence of cholesterol gallstones was related to the increase of the fat intake and the decrease of the crude fiber intake. A study on black stone was carried out with an infrared spectroscopic analysis and scanning electron microscopic observation, and we now proposed a new classification of this type of stones.

Cholecystography↗