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Biomedical subjects

N Yasuda

Publications and source records attributed to N Yasuda.

At least 73 records · Page 4Linked to original sources
PubMed1998

Effect of acarbose (alpha-glucosidase inhibitor) on disaccharase activity in small intestine in KK-Ay and ddY mice.

The hypoglycemic effect and the alpha-glucosidase activity inhibition of acarbose (AC:alpha-glucosidase inhibitor) were investigated in normal and KK-Ay mice, an animal model of noninsulin-dependent diabetes mellitus (NIDDM). AC improved hyperglycemia after an oral administration of maltose or sucrose, dose dependently in normal mice (1, 10, and 50mg/kg body weight) and in KK-Ay mice (50mg/kg). Furthermore, AC (50mg/kg) significantly inhibited maltase and sucrase activities in the small intestines of normal and KK-Ay mice (inhibitory efficacy: sucrase > maltase). The enzymatic inhibition in KK-Ay mice is stronger than in normal mice. However, AC (50 mg/kg) did not suppress the blood glucose in oral lactose tolerance and did not inhibit the lactase activity in either normal or KK-Ay mice. These findings indicate that the AC effect on the inhibition of alpha-glucosidase activity is selective for sucrase and maltase in normal and NIDDM mice.

Acarbose↗
PubMed1997

Relation of social network characteristics to 5-year mortality among young-old versus old-old white women in an urban community.

This study examines age-related differences in the association between social network characteristics and mortality for aged white women. Subjects include a community-dwelling sample of white women aged > or = 65 years (n = 806), who lived in northeast Baltimore, Maryland, in 1984. Three characteristics of social networks were measured: availability of network resources; contact with network resources; and integration into the neighborhood. The association of social network with 5-year mortality was examined with a proportional hazards model adjusting for perceived health status, impairment in physical activities of daily living, number of chronic conditions, and years of education. Analyses were stratified by age (65-74 years, > or = 75 years). Elements of social network contact and neighborhood integration were associated with reduced mortality among women aged > or = 75 years, but not among women aged 65-74 years. In the > or = 75 years group, women who had no contact with children, friends, and group organizations showed hazard ratios (95% confidence intervals (CI)) of 3.1 (1.2-7.5), 2.2 (1.0-4.9), and 2.8 (1.2-6.5), respectively. Women who had lived < or = 10 years in the neighborhood and women who had no interaction with local merchants showed hazard ratios of 2.5 (95% CI 1.3-4.8) and 2.2 (95% CI 1.2-3.9), respectively. Thus, both age and specific aspects of network structure were found to influence the association between social networks and mortality in elderly women.

Aged↗
PubMed1997

Effects of ligation and reperfusion of hepatic afferent vessels on the composition of liver cell membrane in the rat: 1H- and 31P-magnetic resonance spectroscopic analysis.

Biochemical changes that occur within hepatic tissue of the rat during ischemia and subsequent reperfusion were investigated using magnetic resonance spectroscopy of liver extracts. Hepatic ischemia was produced in the rat by a continuous clamping of the left branches of the hepatic artery and portal vein. In the reperfusion experiments, the vascular clamps were released after 30 or 120 min of ischemic periods. At the end of the periods of ischemia and/or reperfusion, the left and middle hepatic lobes were dissected and processed for subsequent 1H-MRS and 31P-MRS analyses. Phosphatidylcholine, sphingomyelin, phosphatidic acid and phosphatidylethanolamine contents all showed reduction of about 30% after 120 min of ischemia. In contrast, the content of lysophosphatidylcholine showed relatively small changes following ischemia. Ten minutes after initiation of reperfusion, further decline of the total phospholipid content resulting in as much 42% reduction was observed. Then it recovered to nearly the control level when ischemia was for 30 min, but to only 65% of the control level when ischemia was for 120 min. The cholesterol/-N-(CH3)3 ratio, generally regarded as a parameter for membrane fluidity, showed about a 40% increase when ischemia was for 120 min, a change toward decreased membrane fluidity. These results appear to reflect ischemia/reperfusion-induced changes of membrane phospholipid metabolism.

Animals↗
PubMed1997

Nitric oxide synthase activities in mammalian parotid and submandibular salivary glands.

Nitric oxide is important as a physiological messenger molecule in various organs and cells. It is synthesized from the amino acid L-arginine by nitric oxide synthase. Here, the specific activities of nitric oxide synthase in the cytosolic fractions of rabbit, bovine, mice, rat, and guinea-pig parotid and submandibular glands were compared. Marked specific activities were detected in the rabbit and bovine parotid and submandibular glands and in the parotid of mice. The activity in rabbit parotid was highest and was similar to that in rabbit brain. The significant activities in the salivary glands were completely blocked in the absence of Ca2+ or the presence of a calmodulin inhibitor. These findings suggest that the rabbit parotid glands are useful for studying the regulation of nitric oxide generation by Ca2+/calmodulin-dependent nitric oxide synthase in salivary glands.

Animals↗
PubMed1997

Plasma Fas ligand, an inducer of apoptosis, and plasma soluble Fas, an inhibitor of apoptosis, in patients with chronic congestive heart failure.

OBJECTIVES: This study sought to examine plasma levels of soluble Fas/APO-1 receptor (sFas), an inhibitor of apoptosis, and soluble Fas ligand (sFas-L), an inducer of apoptosis, and their relation to each other and to other clinical variables, such as New York Heart Association functional class, tumor necrosis factor (TNF) and interleukin-6 (IL-6) in congestive heart failure (CHF). BACKGROUND: It has been recently reported that apoptotic cell death occurs in myocytes of dogs with CHF. Hypoxia is frequently seen in advanced CHF and can stimulate Fas/APO-1 receptors (Fas) to induce apoptosis in cultured myocytes. Fas and Fas ligand (Fas-L) are cell-surface proteins and representative apoptosis-signaling molecules. Fas on the cell membrane induces apoptosis when it binds Fas-L or sFas-L. However, plasma sFas, a molecule lacking the transmembrane domain of Fas, blocks apoptosis by inhibiting binding between Fas and Fas-L or sFas-L on the cell membrane. At present, it is unknown whether plasma sFas-L and plasma sFas increase in the presence of cardiac disease. METHODS: The study included 70 patients (mean [+/-SEM] age 65 +/- 2 years, range 21 to 93) with chronic CHF (coronary artery disease in 28, dilated cardiomyopathy in 27, valvular heart disease in 15) and 62 age- and gender-matched normal control subjects. Plasma levels of sFas, sFas-L, TNF-alpha and IL-6 were measured by enzyme-linked immunosorbent assays using monoclonal anti-human antibodies. RESULTS: There was no significant difference in sFas-L levels between normal subjects and patients in functional classes I to IV; however, sFas increased with severity of functional classification, independent of the underlying disease. sFas levels were significantly higher even in patients in functional class II than in normal subjects and those in functional class I, and were highest in patients in functional class IV (normal subjects; 2.2 +/- 0.1 ng/ml; functional class I: 2.2 +/- 0.2 ng/ml; functional class II: 3.1 +/- 0.2 ng/ml; functional class III: 3.9 +/- 0.3 ng/ml; functional class IV: 5.1 +/- 0.6 ng/ml). Plasma sFas levels were significantly higher in patients with elevated pulmonary artery wedge pressure and a decresed cardiac index than in those with values in the normal range. In patients in functional class IV, there was no significant difference in plasma sFas levels between the survivors and non-survivors during 6-month follow-up. However, plasma levels of sFas tended to decrease in nine patients with clinical improvement (baseline sFas: 5.2 +/- 0.8 ng/ml; 6-month sFas: 4.3 +/- 0.5 ng/ml, p = 0.07) but were similar in patients with no change in functional class. TNF-alpha and IL-6 were increased significantly only in patients in functional class IV, as previously reported, but were not related to sFas. CONCLUSIONS: We found elevated levels of plasma sFas and no increase in plasma sFas-L in human CHF. The increase in sFas may play an important role in the pathophysiologic mechanisms of CHF.

Aged↗
PubMed1997

[Clinical efficacy of lomefloxacin for associated infection in patients with hematological diseases].

We have studied the clinical effect of lomefloxacin (LFLX) for the documented infections in the patients with hematological disorders, and also analyzed the prophylactic usefulness of LFLX for the prevention of succeeding infection after the chemotherapy. Fifty five patients were entered in the trial, and 51 patients were eligible. Among 51 eligible patients, 40 patients were suffered from accompanied infections, and 11 patients were registered for the prophylaxis of the infection. In the group of documented infection, the ratio of out-patients was 62.5%, and 63.0% in prophylactic usage. In the treatment of the documented infection, LFLX was effective in 20 patients; the efficacy rate was 50.0%. In the prophylactic administration, LFLX was effective in 9 patients, yielded the efficacy rate of 81.8%. LFLX was effective for all 5 patients with urinary tract infection, in 10 out of 18 patients with respiratory tract infection (efficacy rate; 55.6%), in 5 out of 12 patients with fever from undetermined origin (41.7%), showed no effect for cholecystitis, colitis, and phlegmon. Bacteriological examinations revealed that all of the bacteria detected as pathogens were eradicated. The efficacy rate in the group of the malignant disorders such as leukemia/ lymphoma was smaller than that of non-tumorigenic diseases as aplastic anemia. As myelodysplastic syndrome (MDS), four infection-bearing patients and five patients with prophylactic usage were analyzed. The efficacy rate of LFLX was 50.0 and 80.0%, respectively, and the overall efficacy rate was 66.7%. All MDS patients without prophylactic administration failed to have infections. Thus, LFLX was thought to be useful in the prevention of succeeding infections after the chemotherapy. No clinical and laboratory adverse reactions were reported.

Adolescent↗
PubMed1997

Mechanism of posturally induced crackles as predictor of latent congestive heart failure.

We investigated the role of changes in pulmonary function in posturally induced crackles (PIC) in 76 patients with various heart diseases. Regional ventilation was evaluated by spirometric gated ventilation scanning using 133Xe in 23 of these patients and its relationship to PIC was analyzed. A change from the sitting to the supine position was associated with a significant decrease in the percent functional residual capacity (FRC, p < 0.01) and significant increases in closing volume (CV), CV/vital capacity (VC) and closing capacity (CC)/FRC (p < 0.01) in the PIC-positive subjects. CV, CV/VC and CC/FRC did not differ significantly between PIC-positive (n = 37) and PIC-negative (n = 39) subjects in the sitting position, but in the supine position, these values were significantly higher in the PIC-positive group than in the PIC-negative group (CV: p < 0.05, CV/VC and CC/FRC: p < 0.01). These results suggest that airway closure was markedly increased in PIC-positive subjects in the supine position compared with PIC-negative subjects. Regional ventilation (V) was assessed in the sitting and the supine position from right lateral images divided into 9 segments from the base to the apex of the lung using spirometric gated ventilation scanning. There was no significant difference in regional ventilation in the sitting position between PIC-negative (n = 11) and PIC-positive (n = 12) subjects; in the supine position, regional ventilation decreased significantly at the base in the PIC-positive group. Findings suggest that PIC at the base of the lungs may be related to airway closure at the base of the lungs in the supine position in PIC-positive subjects.

Adult↗
PubMed1997

Effects of steroid 5alpha-reductase inhibitor ONO-9302 and anti-androgen allylestrenol on the prostatic growth, and plasma and prostatic hormone levels in rats.

ONO-9302 [epristeride; (-)-17beta-(tert-butylcarbamoyl)androsta-3,5-diene-3-carboxy lic acid] is a novel inhibitor of steroid 5alpha-reductase. We studied in vitro and in vivo effects of ONO-9302 on the rat prostatic tissue in comparison with those of the anti-androgen allylestrenol. ONO-9302 inhibited the rat prostatic enzyme with an IC50 value of 11 nM, whereas allylestrenol was about 80,000-fold less potent. The growth of ventral prostate, which was induced by the subcutaneous injection of testosterone propionate in the castrated rats, was significantly reduced by ONO-9302 at oral doses of 1-100 mg/kg/day. Allylestrenol showed a significant effect only at a dose of 100 mg/kg/day. In mature male rats, ONO-9302 significantly reduced the ventral prostate weight at doses of 10-100 mg/kg/day and decreased prostatic 5alpha-dihydrotestosterone (DHT) content associated with a rise in testosterone (T) content at doses of 0.1-100 mg/kg/day. Plasma hormone levels (i.e., T, DHT, luteinizing hormone (LH) and follicle stimulating hormone (FSH)) were not altered significantly. Allylestrenol significantly reduced the ventral prostate weight at doses of 10-100 mg/kg/day. However, unlike ONO-9302, allylestrenol reduced both the prostatic DHT and T contents and also lowered plasma T, DHT, LH and FSH levels at a dose of 30 mg/kg/day. These results suggest that ONO-9302 reduces the prostatic growth by inhibiting the conversion of T to DHT in the prostate without lowering blood T level unlike anti-androgen drugs.

5-alpha Reductase Inhibitors↗
PubMed1997

Rapid apoptotic changes in the gastric glandular epithelium of rats administered intraperitoneally with fusarenon-X.

Fusarenon-X (FX) 1.5 mg/kg was administered intraperitoneally (i.p.) to 6-week-old male Wistar rats for examination of pathologic effects on the glandular stomach. Rats ip-treated with sterilized physiological saline were used as control. FX-administered rats showed dilatation of the stomach with increased fluid contents after 1-4 hr. Light microscopically, a few apoptotic karyopyknosis were seen in chief cells in the basal region at 1 hr postadministration (PA) and mitotic inhibition was evident after 2 hr PA. Marked apoptosis of nuclear pyknosis and cytoplasmic inclusions in both zymogenic and oxyntic cells developed from basal to middle regions of the gastric mucous membrane at 2-4 hr PA with a peak at 3 hr. Apoptotic changes of differentiating neck cells and surface epithelia were less evident. Electron microscopy revealed that the chief cells were the main target of FX-induced apoptotosis. The parietal cells were secondarily involved because they phagocytosed chief cell-derived apoptotic bodies. In situ detection of DNA breaks by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) reaction revealed the positive nuclei after 1 hr PA, which increased with time and reached a peak at 3 hr PA, in accordance with apoptotic changes in histological study. Agarose gel electrophoresis of DNA isolated from the gastric mucosae of FX-administered rats showed ladder pattern of DNA fragments after 1.5 hr PA with the maximum distinctness at 3 hr PA.

Animals↗
PubMed1997

Heterogeneity of corticotropin-releasing factor (CRF).

Although CRH is the major contributor to the physiological regulation of ACTH secretion, it must be recognized that a considerable degree of heterogeneity exists regarding the chemistry and biological activity of various CRF-active substances, some of which still remain to be fully clarified. The widespread extrahypothalamic sources and diverse extrapituitary actions of CRFs suggest that multiple CRF components must act in concert for the organism to cope with the environmental changes and stresses.

Adrenocorticotropic Hormone↗
PubMed1997

Differing influence on delays in the case-finding process for tuberculosis between general physicians and specialists in Mongolia.

The objective of this study is to compare the influence on delays in the tuberculosis case-finding process according to the types of medical facilities initially visited. The subjects include 107 patients 16 years and older who were diagnosed with bacteriologically confirmed pulmonary tuberculosis at nine tuberculosis specialized facilities in Ulaanbaatar, Mongolia from May 1995 to March 1996. Patients were interviewed about their demographic and socioeconomic factors and their medical records were reviewed for measuring delays. Fifty-five patients initially consulted general physicians and the remaining 52 patients initially visited other types of facilities including tuberculosis specialized facilities. Patients who initially consulted general physicians had shorter patient's delays and longer doctor's delays than those who had visited other facilities first. Since the reduction of patient's delay outweighs the extension of doctor's delay among patients who initially consulted general physicians, their total delay was shorter than that of patients who visited other facilities first. The beneficial influence of consulting general physicians first on the total delay was observed after adjusting for patient's age, sex, residence area, family income and family history of tuberculosis. This finding indicates that general physicians play an important role in improving the passive case-finding process in Mongolia.

Adolescent↗
PubMed1997

A follow-up study of preventive effects on low back pain at worksites by providing a participatory occupational safety and health program.

Low back pain is still a common and serious issue at worksites. In order to evaluate preventive effects on low back pain by providing a participatory occupational safety and health program, we conducted a 10 year follow-up study at the Tokyo Metropolitan Bureau of Waste Management and examined yearly changes in the number of compensated and claimed low back pain. The participatory occupational safety and health program is based on a small-sized group and joint employee-employer involvements. This program includes analysis of occupational accidents, revision of the safety procedure manual, participatory training classes, improving and evaluating working procedures and personal protective equipment , and so on. The number of compensated low back pain from 1984 to 1994 has decreased from 318 to 87, and the number of claimed low back pain has decreased from 343 to 92. These results suggest that the participatory occupational safety and health program is effective in prevention of low back pain.

Follow-Up Studies↗
PubMed1997

A comparative study of high-fat diet containing fish oil or lard on blood glucose in genetically diabetic (db/db) mice.

The effects of high-fat diets containing fish oil or lard on blood glucose and plasma insulin after oral glucose loading were compared in genetically diabetic (db/db) mice, one of the animal models of non-insulin-dependent diabetes mellitus (NIDDM) with hyperinsulinemia. The blood glucose levels were significantly decreased in 27% of the mice fed high-fat diets containing 20% fish oil 30 and 60 min after the oral administration of glucose (both; p < 0.05). Conversely, the plasma insulin levels were significantly increased 30 min after the glucose loading as compared to 27% of the mice fed high-fat diets containing 20% lard (p < 0.01). In addition, a significant hypoglycemic effect was observed 60 min after the subcutaneous administration of insulin to mice on the fish oil diet (p < 0.05), whereas no effect was demonstrated in the case of those on the lard diet. The average body weight of the fish oil-treated mice was not significantly different from that of the lard-treated mice. The fish oil diet has a beneficial effect on glucose tolerance by increasing the insulin secretory capacity from pancreatic beta cells and also ameliorating insulin resistance.

Animals↗
PubMed1997

[A study of waste anesthetic gases monitoring and working environmental controls in hospital operating rooms].

There are hazardous factors threatening health care workers, and many hazardous chemical substances have been reported in operating rooms, central supply facilities, laboratories and so on. In Japan, little attention has been paid to exposure to these chemicals and to working environmental controls. Waste anesthetic gases are chemicals concerned, and we conducted environmental monitoring continuously and measured exposure to nitrous oxide, isoflurane and sevoflurane in operating rooms, and examined working environmental controls. The average environmental concentrations of nitrous oxide were about 400 ppm in anesthetists' working areas, and about 180 ppm in surgeons' and instrument nurses' working areas under unscavenged conditions. Under scavenged conditions, environmental concentrations were 70-190 ppm in anesthetists' zones, and 70-90 ppm in surgeons' and instrument nurses' zones. Even under scavenged conditions, operating room personnel are presumed to be exposed to high concentrations of nitrous oxide above ACGIH's TLV and NIOSH's REL. The level of exposure of isoflurane and sevoflurane was 2-4 ppm. Managing general ventilation system and airflow direction, working area under scavenged system, environmental concentration levels of nitrous oxide could be reduced to 20-30 ppm. In order to control occupational exposure to anesthetic gases, it is not sufficient to merely adapt scavenging systems in operating rooms. Working environmental control and occupational hygiene management should be required.

Air Pollutants, Occupational↗