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Biomedical subjects

H Kurihara

Publications and source records attributed to H Kurihara.

At least 361 records · Page 20Linked to original sources
PubMed1984

Effects of tunicamycin on thin-section and freeze-fracture images of microvilli of the duodenal epithelial cells of the mouse.

The effect of tunicamycin, which is known to inhibit the synthesis of N-linked glycoprotein, on the duodenal absorptive epithelial cell of the mouse was studied in thin-section as well as freeze-fracture images. In tunicamycin-treated animals, the apical part of the epithelial cell was almost negative to the PAS reaction. Moreover, microvilli of the epithelial cell became shorter, larger in diameter, and fewer in number in tunicamycin-treated mice. In addition, freeze-fracture images revealed that the population density of membrane particles of the microvillus membrane was lowered by tunicamycin treatment. These results may indicate that the inhibition of synthesis of N-linked glycoprotein causes a decrease of membrane supply from the Golgi apparatus to the apical plasma membrane.

Animals↗
PubMed1984

Cytochemical studies on the localization and functional properties of calcium in anterior pituitary cells.

The localization of calcium and its functional properties in anterior pituitary cells were studied using a potassium pyroantimonate technique. In all kinds of secretory cells, the precipitates of the calcium-pyroantimonate complex were distributed on the limiting membrane of the secretory granule. They were present also in the cytoplasmic matrix, the mitochondrial matrix, small smooth vesicles, coated vesicles, and in the nuclear euchromatin area. The precipitates were usually seen at the contact region between the limiting membranes of two adjacent secretory granules, or between the granule limiting membrane and the plasma membrane. When the tissues were incubated in the medium containing A23187 (10 microM) for 5 min, the deposits on the granule limiting membrane were increased in number and those on the mitochondrial matrix were decreased; the reaction products almost disappeared on the limiting membranes of the secretory granules after membrane fusion following single or multigranular exocytosis induced by A23187-treatment. In addition, small vesicles in the capillary endothelium contained reaction precipitates. Based on these results we propose a hypothetical model for the relationship between the localization of calcium and secretory activity.

Animals↗
PubMed1984

[Growth of human tumor transplanted into nude mice with various genetic backgrounds].

Nude mice with different genetic backgrounds were used for the experiment to evaluate the growth of human and murine tumors in the different hosts. Twelve human tumors including 5 gastric carcinomas (St-4, St-10, St-15, St-40, KS-1), 2 colon carcinomas (Co-3, Exp-42), 1 breast carcinoma (MX-1), 1 bile duct carcinoma (Ch-1), 1 hepatocellular hepatoma (Li-4) and 2 hemangiosarcomas (LC-27-R, LC-27-UR), and one murine tumor spontaneously arisen from C3H/HeN nu/+ mouse were transplanted into the subcutaneous tissue of nude mice with genetic backgrounds of BALB/cA, DDD and ICR (CD-1). BALB/cA-nu was originated from the Central Institute for Experimental Animals, DDD-nu was supplied from the Institute of Medical Science, University of Tokyo and ICR (CD-1)-nu was supplied from Charles River Co., Ltd. Tumors were measured by the width (W) and length (L) three times a week by the same person. The tumor volume (V) was estimated by the formula V = W2 X L/2. Tumor doubling time (Td) during the exponential growth phase was compared between the nude mice with different genetic backgrounds. It was found that Td of MX-1 in DDD-nu mice and Td of St-40 and Exp-42 in BALB/cA-nu mice were shortened in comparison with those of tumors transplanted into nude mice with the other strains. However, no statistically significant differences were observed when t-test of matched pairs and coefficients of correlation were applied to compare Td in the other kinds of nude mice. Nude mice with genetic backgrounds of DDD and ICR (CD-1) were thought to be also useful for various kinds of therapeutic experiments in human tumor xenografts/nude mice system.

Adenocarcinoma↗
PubMed1983

Ultrastructural aspects of the effect of calcium ionophore A23187 on incubated anterior pituitary cells of rats.

In order to study the fine structural effect of calcium influx on secretory activity of rat anterior pituitary cells, small pieces of anterior pituitary were incubated in Krebs' medium containing the calcium ionophore A23187 (0.15 mM) and were examined electron microscopically. Marked changes were present in all types of secretory cells incubated for 3, 12 and 20 min in the medium containing calcium and A23187. Secretory granules tended to accumulate in the peripheral cytoplasm of the secretory cells, and more numerous images of granule release by exocytosis were observed in somatotroph (STH cell), luteotroph (LTH cell), thyrotroph (TSH cell), corticotroph (ACTH cell), type 1 gonadotroph (Type 1 GTH cell), and type 2 gonadotroph (Type 2 GTH cell). In addition to the increase in the number of exocytosis of single granules, the simultaneous extrusion of multiple granules, "multigranular exocytosis", was often observed in all kinds of secretory cells, especially the ACTH-cells. Large numbers of granule cores were often located in large vacuole-like or channel-like structures, irregular in shape and size, which were open to the intercellular or pericapillary space. Some parts of the membrane of the vacuole-like or channel-like structures were coated. These observations are interpreted to suggest that the calcium influx stimulates the extrusion of the secretory granules by single or multigranular exocytosis.

Animals↗
PubMed1983

[Clinical evaluation of cefoxitin in surgery].

Cefoxitin (CFX) was administered to 13 patients who were admitted to the surgical ward of the hospital. The results of the study as follows; Disc susceptibility tests of the 11 strains isolated from the patients to antibiotic were performed and 10 strains showed good susceptibility to CFX. The clinical response was good in all 4 patients with surgical infections. It is noted that 1 patient with mixed infection caused by E. coli, Clostridium sp. and Bacteroides sp. showed good response to CFX. Out of 9 patients treated with CFX for prophylaxis of postoperative infections, 8 patients responded effectively to CFX, and clinical efficacy rate was 88.9%. No side effects were noted due to CFX. It is considered from these results of the study that CFX is a highly effective and safe drug for treatment of infections and for the prevention of postoperative infections in surgery.

Adolescent↗
PubMed1983

[Effect of chemotherapy on the interstitial tissue of a malignant human tumor transplanted into nude mice, with reference to microvessels].

Experimental chemotherapy of cyclophosphamide (CPA) was performed on a human malignant hemangiopericytoma serially transplanted into nude mice with a genetic background of BALB/c and the changes or histological findings and microangiograms (MAG) were investigated. The treatment was performed 2 weeks after tumor inoculation. Either 120 mg/kg or 240 mg/kg of CPA, dissolved in 0.2 ml of physiological saline, was administered once intraperitoneally. On days 1, 2, 4 and 7 after the treatment, mice were sacrificed and each tumor was examined in terms of histological findings and MAG. Although the tumors treated with 120 mg/kg of CPA were suppressed temporarily, the regrowth of the tumors were observed. The tumors treated with 240 mg/kg of CPA regressed without any regrowth. From the observations of MAG, the former showed an avascular area on day 4 after the treatment and the tumor vessels regenerated on day 7 after the treatment. On the other hand, in the latter group, it was found that the normal vascular network developed after the formation of an avascular area 2 days after the treatment. From the histological findings, the former showed to reduce mitotic indeces of 1 or 2 days after the treatment, however the mitotic indeces were found to recover 7 days after the treatment. Mitotic indeces of tumors treated with 240 mg/kg of CPA were observed to be depressed after the treatment. These results suggested that the changes of interstitial tissue were closely correlated well with the destruction and regrowth of tumor cells observed by the growth curve and histological findings. Tumor vessels were thought to play an important role in the cancer chemotherapy, not only as the transport systems of drugs but also as the target of antitumor agents.

Animals↗
PubMed1983

[Evaluation of splenectomy and possible metastasis from gastric cancer, with reference to nonspecific immunological parameters and postoperative survival].

For the complete removal of metastasized lymph nodes at splenic hilus in the operation for gastric cancer, the splenectomy has been widely accepted. In order to reveal justifiable of such splenectomy, nonspecific immunological parameters and postoperative survival were compared between the groups of splenectomized (S) and nonsplenectomized cases (N) in the same stage of gastric cancer. The immunological parameters in N were more stable after surgery than those in S. As to the postoperative survival there was no significant difference. The survival rates showed no definite difference. The postoperative platelet count of S was higher than that of N. It may be concluded that the splenectomy should be avoided unless the metastases are remarkable.

Animals↗
PubMed1983

[Immunological competence of nude mice on the growth of transplantable human tumors--with reference to natural killer cells].

Influences of natural killer cells on the transplantable human tumors was evaluated by using anti-asialo GM1 antibody. Two human gastric adenocarcinomas designated as St-4 (poorly differentiated) and St-40 (well differentiated) were inoculated into nude mice. The effects of anti-asialo GM1 antibody were assessed in terms of tumor doubling time (Td) and 3H-thymidine (3H-TdR) uptake labeling index (L.I.). Whereas the Td of St-4 was significantly shortened by administration of anti-asialo GM1 antibody, no noticeable changes were observed in St-40. This enhanced growth of St-4 was also supported by the elevation of L.I. both in flashing and repeating methods. On the other hand, as the repeated L.I. of St-40 was almost 100% in control tumors, repeated L.I. was not increased by the administration of anti-asialo GM1 antibody. It was supported that natural killer activity of nude mice regulated the growth of transplantable human tumors concerning with the growth fractions.

Adenocarcinoma↗
PubMed1980

Factors influencing long-term survival after aortic valve replacement.

In the aortic stenosis group, the left ventricular (LV) muscle mass index was a good parameter for predicting the prognosis. Associated mitral valve disease had no influence on long term survival after aortic valve replacement. In the aortic insufficiency group, associated mitral valve disease had a marked influence on the results of aortic valve replacement. In general, the aortic insufficiency group had less clinical improvement postoperatively than the aortic stenosis group. In the annuloaortic ectasia group, left ventricular enddiastolic pressure (LVEDP) might be the predictor to the prognosis. This group had the worst prognosis, of the three groups. Early operation should be considered for patients who have no, or only mild symptoms of, aortic valve disease.

Adolescent↗