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Biomedical subjects

H Ohta

Publications and source records attributed to H Ohta.

At least 775 records · Page 43Linked to original sources
PubMed1983

Glucagon-induced somatostatin release from perifused rat hypothalamus: calcium dependency and effect of cysteamine treatment.

Somatostatin (SRIF) release from rat hypothalamus was investigated in vitro with a perifusion system. Glucagon (1 microM) and high potassium concentrations (56 mM) stimulated SRIF release in a calcium-dependent manner. Pretreatment of the rat with cysteamine (30 mg/100 g body weight, 7 h earlier) significantly reduced SRIF release from the hypothalamus in glucagon- and high potassium-stimulated states as well as in the basal state. SRIF release from rat hypothalamus was also stimulated by both dibutyryl cyclic AMP (1 mM) and theophylline (3 mM). These results suggest that glucagon, acting in a calcium-dependent manner and possibly through the adenylate cyclase-cyclic AMP system, stimulates SRIF release from rat hypothalamus and that cysteamine treatment reduces releasable SRIF in the hypothalamus.

Animals↗
PubMed1983

Agromonas oligotrophica gen. nov., sp. nov., a nitrogen-fixing oligotrophic bacterium.

Phenotypic and chemotaxonomic characteristics of five isolates of acetylene-reducing (nitrogen-fixing) oligotrophic bacteria from a paddy soil were investigated. They showed similar phenotypic characteristics: they were aerobic, asporogenous, gram-negative, motile by a polar flagellum, and irregular rods. On full strength nutrient broth (NB) growth was severely suppressed, but well supported on 10- to 10000-fold diluted NB. They consumed glucose but produced no acid, and also utilized phenolic acids such as ferulic acid or p-coumaric acid. The cellular fatty acid composition, quinone system and DNA base composition of the isolates were investigated. Cellular fatty acids mainly consisted of straight-chain unsaturated C18:1 (62-81% of total fatty acids). Ubiquinone Q-10 and a high guanine-plus-cytosine content (65.1-66.0 mol%) were found. The taxonomic status of the isolates is discussed and a new genus, Agromonas, with a single species Agromonas oligotrophica sp. nov., is proposed for these isolates. The type strain of A. oligotrophica is JCM 1494.

Bacteria↗
PubMed1983

Prostaglandin F2 alpha concentrations in the cerebrospinal fluid of children with febrile convulsions, epilepsy and meningitis.

Cerebrospinal fluid prostaglandin F2 alpha (CSF PGF2 alpha) levels were measured by radioimmunoassay in children as follows: Febrile convulsions (31 cases), epilepsies (32 cases), meningitides (31 cases) and non-neurological diseases (20 cases), totaling 114 cases. A 4.5-fold increase in CSF PGF2 alpha levels was seen in simple febrile convulsion, and a 2.5-fold increase in those with complex febrile convulsion as compared to those with non-neurological diseases. On the other hand, no increase in CSF PGF2 alpha levels was seen in children with epilepsy. When the body temperature was normal, the mean CSF PGF2 alpha levels showed no relation with age. When the body temperature was between 37.5 degrees C and 40 degrees C, the CSF PGF2 alpha levels in infants were higher than those in older children. The CSF PGF2 alpha levels in children with meningitis were high. The mean CSF PGF2 alpha levels in bacterial meningitis were not statistically (p greater than 0.05) different from those in viral meningitis. The CSF PGF2 alpha levels in meningitis were high on admission and gradually decreased with therapy. The results of our studies indicate that PGF2 alpha of the central nervous system markedly increased in infants and children with febrile convulsions or meningitis but not in those with epilepsy.

Adolescent↗
PubMed1983

Activation of chicken alternative complement pathway by fowlpox virus-infected cells.

Fresh normal chicken serum (NCS) which lacked virus-neutralizing antibody to fowlpox virus (FPV) was found to inhibit the appearance of the cytopathic effect of the virus, virus growth, and plaque formation in chicken embryo cells. Immunofluorescent examination revealed the deposition of the third component of complement (C3) on FPV-infected chicken embryo cells incubated with fresh NCS. The inhibitory activity of fresh NCS on viral cytopathic effect was independent of the Ca2+ ion and was abrogated by treatment of fresh NCS with inulin or zymosan. Similarly, deposition of C3 on FPV-infected cells occurred independently of the Ca2+ ion and was inhibited by treatment of fresh NCS with inulin or zymosan but was not inhibited by absorption with FPV-infected cells. These results suggest that antibody-independent activation of complement by FPV-infected cells via the alternative pathway caused the inhibition of the virus growth as well as the C3 deposition. Involvement of complement activation as nonspecific host response to virus infection was also suggested by the demonstration of the C3 deposition in the skin lesions of FPV-infected chickens.

Animals↗
PubMed1983

Learning set formation in slow lorises (Nycticebus coucang).

In primates, learning set formation has been reported in various simian species, but in only few prosimian species. The formation of visual discrimination learning set was tested on a nocturnal prosimian species, slow lorises (Nycticebus coucang). Their performance was higher than that of some New World monkeys. This confirmed the suggestion from the data on black lemurs (Lemur macaco) that there is an overlap between prosimians and simians in learning set ability.

Activity Cycles↗
PubMed1983

Activation of tubuloglomerular feedback in rat nephrons by sera from rabbits with fulminant hepatic failure.

Experiments were designed to determine whether substance(s) other than electrolytes might activate tubuloglomerular feedback in experimental fulminant hepatic failure. Severe hepatic damage and renal dysfunction were induced by intravenous administration of D-galactosamine. Sera from normal or D-galactosamine-treated rabbits were dialyzed against glucose solution to reduce electrolyte concentrations. Tubuloglomerular feedback response was evaluated in rat nephrons by measuring the early proximal flow rate (EPFR) during orthograde perfusion of the loop of Henle. EPFR was reduced by 28 and 48% with Ringer's solution and sera from D-galactosamine-treated rabbits, respectively, but was not altered by normal sera. Substance(s) other than electrolytes in the sera from D-galactosamine-treated rabbits might activate the tubuloglomerular feedback to reduce glomerular filtration.

Animals↗
PubMed1983

Effect of prostaglandin E1 on vasoactive intestinal polypeptide release from the hypothalamus and on prolactin secretion from the pituitary in rats.

In order to elucidate the mechanisms by which prostaglandin (PG) affects PRL secretion, the effect of PGE1 on vasoactive intestinal polypeptide (VIP) release from the rat hypothalamus was examined by determining plasma VIP levels in rat hypophysial portal blood in vivo and VIP release from the perifused hypothalamus in vitro. Intraventricular injection of PGE1 (1 and 5 micrograms/rat) caused a 2- to 3-fold increase in the concentration of plasma VIP in hypophysial portal blood in anesthetized rats. The flow rate of portal blood was slightly increased after the injection of PGE1. VIP release from the perifused rat hypothalamus was stimulated by high potassium levels (56 mM). The infusion of PGE1 (10 microM) resulted in a significant increase in VIP release from the hypothalamus in vitro. Both these responses were calcium dependent. The intraventricular injection of PGE1 (1 and 5 micrograms/rat) resulted in a dose-related increase in peripheral plasma PRL levels in the rat. These findings suggest that PGE1 plays a stimulatory role in regulating VIP release from the hypothalamus into hypophysial portal blood and causes PRL secretion from the pituitary in rats.

Alprostadil↗
PubMed1983

The role of noradrenergic and serotonergic systems in the hippocampal kindling effect.

The role of the noradrenergic and the serotonergic systems in the development of hippocampal and amygdaloid kindling was studied. Dorsal noradrenaline bundle lesions markedly facilitated the formation of hippocampal and amygdaloid kindling. The most significant facilitation was observed in the earliest phase of kindling. Cortical noradrenaline content decreased by about 70% after dorsal noradrenaline bundle lesions. Midbrain raphe nuclei (both dorsal and medial raphe nuclei) lesions did not have any effect on the formation of both hippocampal and amygdaloid kindling. These results indicate that the dorsal noradrenaline bundle system plays an inhibitory role in the development of the seizure discharges and the behavioral convulsions in hippocampal and amygdaloid kindling.

Amygdala↗
PubMed1983

Myocardial protection during cardiac ischemia by coronary perfusion with cold lactated Ringer's solution plus mannitol.

This experimental and clinical study evaluates the degree of myocardial protection afforded by coronary perfusion with cold lactated Ringer's solution plus mannitol. In the experimental study, diluted blood at 30 degrees C (Control G.), lactated Ringer's solution at 4 degrees C (G. A), 1,000 ml lactated Ringer's solution plus 200 ml of 20% mannitol at 4 degrees C (G. B), and 1,000 ml lactated Ringer's solution plus 500 ml of 20% mannitol at 4 degrees C (G. C) were used for coronary perfusion. The myocardial-protecting effect of each perfusate was evaluated by examining serum isoenzymes (CPK-MB, LDH1+2), left ventricular function (Vmax, LVEDP, CO), and the ultrastructure of myocardium. there were no significant differences in myocardial changes between the control group, G. A and G. B. Left ventricular enddiastolic pressure increased significantly in G. A and a significant increase in CPK-MB was seen in G. C. Mitochondrial scores for each group were 98 (Control G.), 86 (G. A), 93 (G. B), and 51 (G. C). Minimal myocardial change was seen in G. B. In the clinical study aortic root perfusion with cold lactated Ringer' s solution (400 m Osm) under aortic cross clamping (27-144 min) was employed in 25 patients. They all survived and CPK-MB returned to preoperative values within 49 hours after operation. In 6 cases, the ultrastructure of left ventricular papillary muscle was examined. It was confirmed that no significant mitochondrial changes developed during aortic cross-clamping.

Animals↗
PubMed1983

Effects of hypertonic mannitol on renal function in open heart surgery.

An extracorporeal bypass was performed in mongrel dogs for 2 hours with or without hypertonic mannitol infusions. In animals given mannitol, the plasma osmolality was elevated maximally to 344 +/- 7.1 mOsm/L and the urine volume was maintained well during bypass. A hypertonic mannitol solution was effective in maintaining the CPAH during and after bypass, but was not effective in minimizing the reduction in Ccr. When the mean arterial pressure during bypass was kept at 60 mmHg, the carbon filling rates in glomeruli showed the favorable effects of mannitol upon renal function, but no effects were observed at a mean arterial pressure of 80 mmHg. In 11 patients who had undergone a bypass lasting more than 2 hrs with mannitol infusions, the plasma osmolality reflected the serum mannitol level and reached 320 +/- 11.0 mOsm/L at 150 min of bypass. The mean urine volume was 5.0 +/- 3.3 ml/min/M2 during the bypass, which was about 7 times as great as before the bypass. The Ccr increased during the first 30 min of the bypass, but it fell to about one half of the initial value after 90 min of the bypass. It was concluded that a hypertonic mannitol solution is effective in maintaining the RPF and urine volume during and after the bypass and that it also preserved the glomerular perfusion even at a low arterial pressure.

Acute Kidney Injury↗
PubMed1983

[Behavioral effects of ethyl loflazepate and its metabolites].

The behavioral effects of ethyl loflazepate and its metabolites were investigated in mice and rats, and they were compared with those of diazepam, nitrazepam and lorazepam. Locomotor activity of rats in open-field situation was increased with a wide range of doses of ethyl loflazepate and with large doses of nitrazepam. The anticonflict effect of ethyl loflazepate was slightly more potent than that of diazepam and much more potent than that of lorazepam. In suppressing muricide of both olfactory bulbectomized and raphe lesioned rats, ethyl loflazepate was approximately as potent as diazepam and much less potent than nitrazepam and lorazepam. Ethyl loflazepate was more potent than diazepam, nitrazepam and lorazepam in preventing pentetrazol-induced convulsion. In potentiating thiopental anesthesia in mice and impairing rotarod performance in mice and rats, ethyl loflazepate was less potent than diazepam, nitrazepam and lorazepam. The pharmacological activities of CM6913 and CM7116, metabolites of ethyl loflazepate, were approximately as potent as that of ethyl loflazepate. The duration of action of ethyl loflazepate was longer than those of the metabolites. These results indicate that ethyl loflazepate possesses pharmacological properties characteristic to benzodiazepines, and it is approximately equal to diazepam in potency and has a longer duration of action than diazepam, nitrazepam and lorazepam.

Aggression↗
PubMed1983

Newly established uterine cervical cancer cell line (SKG-III) with Regan isoenzyme, human chorionic gonadotropin beta-subunit, and pregnancy-specific beta 1-glycoprotein phenotypes.

The production of Regan isoenzyme (heat-stable, L-phenylalanine-sensitive term-placental alkaline phosphatase), human chorionic gonadotropin beta-subunit, and pregnancy-specific beta 1-glycoprotein by newly characterized human uterine cervical cancer cell lines, SKG-IIIa and SKG-IIIb, is reported. These cell lines were derived from a moderately differentiated epidermoid cancer partially mixed with epidermoid clear-cell components. At the end of the first 4 months in culture 2 sublines with different morphologies were identified. In nude mice, SKG-IIIa produce clear-cell epidermoid cancer with much glycogen, while SKG-IIIb grew as a moderately differentiated epidermoid cancer rich in tonofilaments. The presence of Regan isoenzyme was established by biochemistry, enzyme cytochemistry, immunocytochemistry, and immunoelectrophoresis. However, the copresence of small amounts of early placental alkaline phosphatase was also demonstrated. The alkaline phosphatase specific activities of SKG-IIIa cells and SKG-IIIb cells were 3.7 and 1.4 nmol per mg protein per min, respectively. The existence was proven by radioimmunoassay of human chorionic gonadotropin beta-subunit (SKG-IIIa, 5.0 mlU/mg protein; SKG-IIIb, 4.4 mlU/mg protein), pregnancy-specific beta 1-glycoprotein (SKG-IIIa, 0.7 ng/mg protein) in the culture media as a tumor cell product. The described cell lines may serve as a more representative model system for studies of regulation of oncodevelopmental genes in gynecological tumors in general and in epidermoid cervical cancer in particular.

Alkaline Phosphatase↗
PubMed1983

[Treatment of multiple myeloma. High-dose intermittent administration of cyclophosphamide and prednisolone--follow up study of 10 years period].

Twenty patients with plasma cell myeloma were treated with high-dose (10 mg/kg) intermittent administration of cyclophosphamide for remission induction and maintenance therapy. High-dose intermittent administration of glucocorticosteroid hormone was also performed usually in parallel with large-dose of cyclophosphamide. A significant objective response was obtained in 12 of 20 patients (60.0%). The median survival was 32 months in all cases; 47 months in the responding cases. The response rate was not affected by the class of M-protein, the type of light-chain and/or the presence of bone lesions. All responders were on the 3rd stage. High-dose intermittent administration of cyclophosphamide was evaluated as very useful since it showed equivalent effects obtained by combination chemotherapy regimens, hardly producing bone marrow suppression.

Adult↗