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Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 847 records · Page 47Linked to original sources
PubMed1988

Elicitation of diacetylenic compounds in suspension cultured cells of eggplant.

Induction of stress metabolites in the suspension cultured cells of eggplant (Solanum melongena L.) was examined. When autoclaved RNase A or nigeran, both of which are nonspecific phytoalexin elicitors in bean cells, were added to the cell culture of eggplant, greatly enhanced levels of three compounds were observed. One of them was cis-pentadeca-6-ene-1,3-diyne-5,15-diol, a novel diacetylenic compound. This compound has considerable fungitoxic activity. Also identified was falcarindiol, another fungitoxic diacetylenic compound previously reported as one of the phytoalexins in infected tomato fruits and leaves. Elicited compounds preferentially accumulated in the culture medium rather than in the cells and decreased to original levels during prolonged culturing. The elicitation of these compounds was closely correlated with cellular damage in terms of the decrease of growth rate and was inhibited by 10 micromolar cycloheximide.

Journal Article↗
PubMed1988

Antitumor activity and neutrophil-selective hematopoietic toxicity of busulfan analogs in mice.

The antitumor activity and hematopoietic toxicity of two busulfan analogs were evaluated in comparison with those of busulfan. Although a program of five daily ip treatments with busulfan was not effective in treating sarcoma 180-bearing mice, a fluorine-containing busulfan analog, 1,4-butanediol di-2,2,2-trifluoroethanesulfonate (BFS), and a water-soluble analog, 1,4-butanediol diisethionate (BIT), were significantly effective when given on the same schedule. Busulfan did not appreciably prolong the life span of either P388- or Meth A-bearing mice, whereas BFS and BIT produced significant increases in the life span. It is worth noting that both the analogs were definitely less toxic to the host mice than busulfan. All the drugs examined exhibited suppressive effects on the counts of total WBCs, neutrophils, and lymphocytes. Relative toxicity toward neutrophils versus lymphocytes was increased significantly in the BFS and BIT treatments compared with busulfan treatment. It seems that the toxicity of busulfan in host mice might be due to unidentified side effects other than bone marrow suppression. These results suggest that BFS and BIT could be improved substitutes for busulfan.

Alkanesulfonates↗
PubMed1988

The epidemiological study of physical morbidity in schizophrenics--2. Association between schizophrenia and incidence of tuberculosis.

The incidence of tuberculosis was investigated among 3,251 patients residing in Nagasaki city and diagnosed as schizophrenia between 1960 and 1978. Eighty-two of the patients had tuberculosis. The expected number of schizophrenic patients with tuberculosis was calculated using the annual incidence rate of tuberculosis in the general population, and the difference between the observed number and the expected number was examined. The incidence rate of tuberculosis was significantly higher than that of the general population for both male and female schizophrenic patients. Similarly, the incidence rates of tuberculosis among schizophrenic patients born before 1925 and those born after that year were significantly higher than those of the corresponding age groups in the general population. In this paper we discuss these findings with reference to the literature on similar epidemiological studies.

Adult↗
PubMed1988

Exchange blood transfusion for acute hepatic failure: its limited availability depending on the type of injury in rats.

The efficacy of exchange blood transfusion for acute hepatic failure was evaluated using rats. Rats receiving a dose of carbon tetrachloride died later than 24 h after dosing. When their blood was replaced with blood from normal rats at 24 h, survival time was prolonged, and hepatic protein synthesis was enhanced at 36 h with improved prothrombin time (PT). Those rats surviving 120 h showed better histological grade of recovery from injury after treatment. In contrast, dimethylnitrosamine (DMN)-intoxicated rats showed no such improvement in survival time or PT. In rats given a nonfatal dose of carbon tetrachloride, serum glutamic-pyruvic transaminase values were five times higher than those in rats given DMN despite similar maximal PT. The benefit of exchange transfusion for acute hepatic failure may differ depending on the mechanism of development in rats. Enhanced hepatic protein synthesis may contribute to its effect.

Acute Disease↗
PubMed1988

Comparative study of affective disorders in three Asian countries. I. Differences in diagnostic classification.

A study aimed at the standardization of symptom evaluation of patients with depression was carried out as the first step in an extensive collaborative study on affective disorders between centers in Nagasaki, Shanghai and Seoul. This study was initiated in order to clarify the factors affecting the low reported prevalence rates of depressive disorders in Asia. No significant difference in evaluation of psychiatric symptoms was observed between the 3 centers. Nevertheless, the diagnoses given by ICD-9 showed very interesting differences. For any given case, Nagasaki tended to make a diagnosis of an affective psychosis depression, while Shanghai made a diagnosis of neurotic disorder. No significant tendency was observed in the Seoul center. These findings are discussed in terms of their importance for future international collaborative studies.

Affective Disorders, Psychotic↗
PubMed1988

Change of hepatitis B virus DNA distribution associated with the progression of chronic hepatitis.

Hepatitis B virus (HBV) DNA was detected by in situ hybridization in 53 out of 74 liver specimens from patients with chronic HBV infection. The distribution of HBV DNA was classified into three patterns: diffuse (HBV DNA distributed diffusely, within the section of specimen), lobular (HBV DNA was present in 1/3-2/3 of the section) and spotty. All three specimens from asymptomatic HBV carriers showed the diffuse pattern. In the advanced stage of liver disease (chronic active hepatitis with severe activity and liver cirrhosis), a decreased number of specimens showed the diffuse pattern, whereas the number of specimens with the lobular pattern increased. From these data, we conclude that HBV may replicate diffusely in the liver in the early stage of chronic liver disease, and the site of HBV replication becomes localized in the advanced stage of the disease. The main target cells of immunocytes may be hepatocytes undergoing HBV replication, because HVB DNA was frequently detected in areas of focal, piecemeal and bridging hepatic necrosis.

DNA, Viral↗
PubMed1988

Isolation and characterization of simian immunodeficiency virus from mandrills in Africa and its relationship to other human and simian immunodeficiency viruses.

Two isolates of simian retrovirus related to the human immunodeficiency virus (HIV) were obtained from apparently healthy mandrills, Papio (Mandrillus) sphinx, in western equatorial Africa. This virus, designated SIVMND (simian immunodeficiency virus from mandrills), appeared morphologically similar to HIV by electron microscopy, showed Mg2+-dependent reverse transcriptase activity, and induced cytopathic effect in human CD4-positive cells. Western blotting (immunoblotting) analyses revealed that the gag and pol products of SIVMND showed cross-reactivity with those of known HIVs and SIVs. Molecular clones covering full-length viral DNA were obtained from closed circular extrachromosomal DNA of SIVMND-infected cells. By clone-on-clone hybridization with known retroviruses of the HIV and SIV groups, SIVMND showed similar cross-hybridization with HIV-1, HIV-2, SIVAGM (African green monkey-derived SIV), and SIVMAC (rhesus macaque-derived SIV) in the gag and pol regions only at low stringency but not at high stringency, a result indicating that SIVMND is a new member of the HIV-SIV group. The existence of distinct SIVs in different monkey species suggest that recent interspecies transfer of HIV-SIV is unlikely in nature.

Animals↗
PubMed1988

Production and characterization of monoclonal antibodies specific for the transmembrane protein of simian immunodeficiency virus from the African green monkey.

Mouse monoclonal antibodies were produced against simian immunodeficiency virus (SIV) from the African green monkey (SIVAGM). The antibodies reacted with the transmembrane protein of all five SIVAGM isolates but not with those of SIVs from the rhesus macaque and mandrill or of human immunodeficiency virus type 1 or type 2, indicating that they recognize a species-specific epitope strongly conserved in SIVAGM. The transmembrane proteins of several SIVAGM isolates were found to vary in molecular size, even in the deglycosylated form after N-glycanase treatment, indicating heterogeneity of the SIVAGM isolates.

Animals↗
PubMed1988

Intravascular coagulation in acute liver failure in rats and its treatment with antithrombin III.

Liver damage was induced in rats by injection of dimethylnitrosamine (DMN) or carbon tetrachloride (CCl4). Fibrin clots were observed in the hepatic sinusoids at 12 hours and soluble fibrin monomer complexes were markedly detected at 24 hours only in the rats given DMN. When antithrombin III concentrate was infused at 12 hours there was a dose dependent improvement of the values of serum total bilirubin, SGPT, prothrombin time, peripheral platelet count, and plasma fibrinogen and coagulation factor VIIIC and of the histological degree of liver injury at 24 hours in the DMN group. The CCl4-group showed no such improvement. Intravascular coagulation may complicate the course of certain types of acute liver injury and contribute to its aggravation in rats. Under such circumstances, treatment with antithrombin III concentrate would be beneficial.

Animals↗
PubMed1988

Thermogenesis in brown adipose tissue of genetically obese, diabetic (KKAY) mice.

Thermogenesis of brown adipose tissue (BAT) of genetically obese mice, KKAY mice, was examined by measuring the BAT mitochondrial guanosine diphosphate (GDP) binding as an index of thermogenesis and comparing it with that of normal C57BL mice. No great difference in GDP binding was observed in KKAY and C57BL mice fed a stock diet. However, when they were given a sucrose solution, the increase in BAT mitochondrial GDP binding of KKAY mice (+22%) was much lower than that of C57BL mice (+106%). A high fat diet increased BAT mitochondrial GDP binding in KKAY mice to the same extent (+82%) as in C57BL mice. When the mice were fasted for 48 h, BAT mitochondrial GDP binding of C57BL mice decreased by 70%, while that of KKAY mice showed no change. Both acute exposure to cold and norepinephrine injections increased GDP binding in KKAY mice by 90% and 131%, respectively. These results indicate that low BAT thermogenesis in response to sucrose intake may be a cause of obesity in KKAY mice, and this may be brought about by defects in the central nervous system.

Adipose Tissue, Brown↗
PubMed1988

An EMG analysis on regulation of the diaphragm and abdominal muscles.

Neural mechanisms regulating activities of diaphragm and abdominal muscles were investigated on anesthetized, tracheostomized and spontaneously breathing dogs. EMGs of costal diaphragm and external oblique (EO)abdominal muscle were recorded by fine-wire electrodes. The electrodes for diaphragm-EMG were implanted without opening abdominal cavity using laparoscopy. During quiet breathing the mean firing frequency of diaphragm-EMG was 7.6 +/- 0.7 (S.D.) Hz. The discharge spikes of diaphragm-EMG observed in early-inspiration or in post-inspiratory phase, were low in amplitudes, consistent with previous reports that phrenic motoneurons were comprised of two populations. During quiet breathing spikes were not observed in EO-EMG in a half of the animals, and were tonically-firing in the remaining dogs. Hypercapnia increased firing frequency of diaphragm-EMG, but did not recruit spikes of high amplitude. On the other hand, hypercapnia recruited EO-spikes of higher amplitude, and increased firing frequency. When spikes fired tonically in EO-EMG, hypercapnia suppressed these spikes during inspiration. Airway occlusion gradually recruited EO units of higher amplitude. Mechanical stimulation of upper airway suppressed tonic-EO activity during inspiration. In conclusion, we demonstrated that 1) abdominal wall is not related with control mechanism of diaphragm; 2) the control mechanism of dog's EO differs from cat's internal intercostal muscles; and 3) the tonic component of EO is affected by respiratory commands from higher neuronal architecture.

Abdominal Muscles↗
PubMed1988

Glucagon and insulin for the treatment of hepatic failure in dimethylnitrosamine-intoxicated rats.

When rats received dimethylnitrosamine every 24 h until death, plus hormone treatment after the first 24 h, the survival was enhanced between 100 and 140 h compared with the control rats, with attenuated derangements of prothrombin time and serum albumin levels at 120 h. In rats given a single dose of dimethylnitrosamine, hepatic DNA synthesis peaked at 48 h. The synthesis was increased after hormone treatment when started immediately, but not when delayed for 24 h. Hormone treatment for 3 days starting 24 h after a single dose of dimethylnitrosamine produced a rapid normalization of decreased hepatic protein content on day 9, although hepatic DNA content was not affected. These results suggest that this treatment is effective for hepatic failure, and the promotion of restoration of liver function is a contributing factor to its effect, in addition to the stimulation of hepatocyte proliferation.

Animals↗
PubMed1988

Microfossils in metasediments from Prins Karls Forland, western Svalbard.

The stratigraphic importance of fossils is never more apparent than in attempts to unravel the complexities of metamorphic terrains. The age and stratigraphic relationships of the thick metasedimentary and metavolcanic succession of Prins Karls Forland, western Svalbard, have been the subject of investigation and debate since the early part of this century (Hoel 1914; Craig 1916; Tyrrel 1924), and sharply different interpretations have been proposed (e.g. Harland et al. 1979; Hjelle et al. 1979). Until now, such interpretations have been unconstrained by palaeontological data, an understandable consequence of the metamorphic alteration undergone by these rocks. In this paper, we report the discovery of stratigraphically useful microfossils preserved in chert nodules from carbonaceous, dolomitic shales on northern Prins Karls Forland. These fossils have significant implications for the stratigraphic and structural interpretation of Forland metasediments, as well as for the more general problem of palaeontological prospecting in severely deformed and metamorphosed terrains, including those characteristic of the Archean Eon.

Fossils↗