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Biomedical subjects

K Okamura

Publications and source records attributed to K Okamura.

At least 289 records · Page 16Linked to original sources
PubMed1992

[Clinical characteristics and prognosis of renal cell carcinoma. Statistical evaluation of possible determinants for distant metastasis, venous tumor thrombi, and lymph node metastasis].

To clarify the recent clinical characteristics of renal cell carcinomas and to evaluate possible determinants for metastasis and venous tumor thrombi, the authors reviewed data from 99 renal cell carcinoma patients treated at Nagoya University Hospital between 1980 and 1989. According to Robson's classification, stage I tumors were found in 48 patients, stage II in 9, stage III in 16, and stage IV in 26. Incidentally detected tumors appeared to be on the increase in recent years. Grade 1 tumors were significantly associated with low-stage tumors and expansive growth. Univariate and multivariate analyses using a logistic regression model demonstrated that venous tumor thrombi and histological grade were significantly related to distant metastasis. Univariate analysis revealed relative risks of 4.7 for venous tumor thrombus presence (pV1b-pV2 vs. pV0-pV1a, p = 0.005) and 8.5 for histological grade (grades 2 and 3 vs. grade 1, p = 0.04). Local invasion (pT3 vs. pT2a-pTb: a relative risk of 7.5, p = 0.0009) and infiltration pattern (INF beta and INF gamma vs. INF alpha: a relative risk of 11.5, p = 0.002). were associated with venous tumor thrombi. Local invasion (pT3 vs. pT2a-pT2b: a relative risk of 6.6, p = 0.03) was the only significant determinant for lymph node metastasis. The 5-year actuarial survival rate was 60.0% for all 99 patients. The 5-year survival rates for stage I and II tumors were, respectively, 91.8% and 64.8%.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Renal Cell↗
PubMed1992

[Biochemical analysis of the external urethral sphincter of female rabbits].

The proportion of fast and slow myosin molecules in external urethral sphincter (EUS) was studied. The contents of fast and slow myosin light chains in EUS from 6 female rabbits (Japanese White, 6-month-old) were estimated using two-dimensional electrophoresis. The percentages of fast and slow myosin molecules were 54.5 +/- 14.9 and 46.0 +/- 14.9, respectively. It was thus shown that female rabbits EUS is composed of both fast and slow muscle fibers. The ratio of fast to slow myosins in female EUS was different from that in male EUS (fast myosin 90%). These results implicate that female and male EUS would be functionally distinct.

Animals↗
PubMed1992

[Hematological values in fetal blood by cordocentesis].

Reference ranges for four hematological parameters--hemoglobin, hematocrit, white blood cell and platelet count--in each gestation were established from values for fetal blood samples obtained by cordocentesis from 72 pregnancies at 16-39 weeks gestation. These 72 fetuses turned out as normal or single malformations which should not affect fetal hematological values. Significant correlations were observed between hemoglobin, hematocrit and platelet counts and the number of weeks of gestation. No correlation was found between the white blood cell count and gestational age. Fetal anemia (hematocrit was below the lower limit of the 95% confidence interval) was found in 18 (7%) of all the fetuses that underwent cordocentesis, including nonimmune hydrops fetalis (8 cases), Rh isoimmunization (4 cases), twin-to-twin transfusion syndrome (3 cases), trisomy 18 (2 cases) and autoimmune thrombocytopenia (1 case). Of 26 hydropic fetuses, 8 (31%) were anemic. The prognosis of those fetuses depended on either the gestational age or the severity of the fetal anemia. Our results are useful in diagnosing fetal hematological disorders and to make decisions for fetal therapy.

Anemia↗
PubMed1992

[Immunological mechanism of pregnancy and miscarriage--a study with a murine spontaneous miscarriage model].

In order to investigate the immunological mechanisms of pregnancy, fluorocytometric and immunohistochemical analysis of the cells was performed in the placenta and spleen of a murine spontaneous miscarriage model (CBA/J x DBA/2) and control (CBA/J x BALB/c). There was a significant difference between the miscarriage rate for the miscarriage model and that for the control, even though H-2 in these two group is matched. The analysis also was performed in a miscarriage model immunized with male splenocytes. Moreover, the effect of gamma-interferon, a potentiator of NK cell activity, on pregnancy was examined. Interferon treatment increased the miscarriage rate. In pregnancy, the number of splenocyte positive Asialo-GM1 or LFA-1 decreased and the intensity of these antigens decreased, as well. Interleukin-2R positive cell increased in number as well as intensity. In the miscarriage model group successfully treated by immunization, the number of Asialo-GM1 positive cells and L3T4 positive cells decreased, whereas they increased in the unsuccessfully treated group. Asialo-GM1 positive cells in the placenta of successful pregnancy decreased in number, and those in miscarried pregnancy increased. In conclusion, the success of the immunization treatment for habitual abortion depends on how to suppress NK cell activity in a linkage with the helper T-cell.

Abortion, Habitual↗
PubMed1992

A new surgical technique for voice restoration after laryngopharyngoesophagectomy with a free ileocolic graft: preliminary report.

We describe a new one-stage surgical technique for voice restoration combined with reconstruction of the cervical esophagus after laryngopharyngoesophagectomy with a free ileocolic autograft. Reconstruction of the alimentary tract is accomplished with the colonic segment, and the phonatory shunt is fashioned from the terminal ileum. The ileocolic valve, reinforced by "cecal application," functions as an inherent valve that prevents aspiration through the shunt. Six patients underwent reconstruction with this method. There was no graft necrosis, although one venous anastomosis required correction because of kinking. There were two hospital deaths: one patient died of multiple organ failure in the perioperative period and the other died of a recurrence of the disease. The remaining four patients were tolerating a regular diet at discharge from the hospital. Five of the six patients were able to achieve a fair to good voice.

Aged↗
PubMed1992

Gastric antisecretory and antiulcer actions of interleukin-1. Evidence for the presence of an "immune-brain-gut" axis.

Increasing evidence suggests that interleukin-1 (IL-1), a cytokine mainly produced by activated monocytes/macrophages, has various biological actions in addition to its immunological activities. In the present study, we examined the effect of IL-1 on gastric secretion and gastric ulcer formation in rats. Gastric secretion was assessed in conscious pylorus-ligated rats weighing approximately 200 g. The peripheral injection of IL-1 resulted in a dose-related inhibition of gastric acid output. The central injection of IL-1 similarly reduced gastric acid secretion at 100 times smaller doses than peripherally injected IL-1, suggesting that this gastric antisecretory action of IL-1 is mediated by the central nervous system. In addition, it was found that this inhibitory effect of IL-1, either peripherally or centrally administered, was still evident at 8 h after injection, indicating the long-lasting property of this IL-1 action. On the basis of these antisecretory actions of IL-1, we determined whether or not pretreatment with IL-1 would prevent experimentally induced gastric ulcer formation. As expected, the central administration of IL-1 dose-dependently suppressed the development of gastric mucosal lesions induced by water-immersion restraint stress, a well-established ulcerogenic procedure. These results clearly demonstrated that IL-1 has potent antisecretory and antiulcer effects that are mediated by the central nervous system. Moreover, these findings suggest that there may exist an "immune-brain-gut" axis, which is involved in the regulation of gastric secretion and mucosal homeostasis, especially under certain pathophysiological conditions that activate the immune system to release various cytokines including IL-1.

Animals↗
PubMed1992

[Long-term clinical results after aortic valve replacement with mechanical heart valves and mitral valve replacement with porcine valves].

Long-term clinical results of aortic valve replacement (AVR) with mechanical heart valves and mitral valve replacement (MVR) with porcine valves were analysed. Sixty-three patients received isolated AVR and 48 received isolated MVR. Sixty-eight patients with MVR including double or triple valve replacement were also added in order to evaluate the primary tissue failure (PTF). The patients with operative deaths were excluded. Survival rate at 11 years in AVR was 68 +/- 10% and 67 +/- 15% in MVR without statistical difference. At 11 years, 76 +/- 8% of the patients in AVR were free from valve-related complications in contrast with the poor result of 34 +/- 31% in MVR (p less than 0.01). Main cause of this poor result in MVR was PTF as indicated in following event free rates; 83 +/- 9% at 7 years, 61 +/- 25% at 10 years and 49 +/- 31% at 13 years. There was no statistical difference between patients of above 50 years and below 49 years in PTF. Valve-related death event free was 93 +/- 5% in AVR and 86 +/- 11% in MVR at 11 years (not significant), however, there was statistical difference in re-operation event free rate as 94 +/- 5% in AVR and 76 +/- 11% in MVR at 11 years (p less than 0.001). These results suggest that the use of porcine valves in mitral position is confined to the selected patients.

Adult↗
PubMed1991

Endogenous basic fibroblast growth factor-dependent induction of collagenase and interleukin-6 in tumor necrosis factor-treated human microvascular endothelial cells.

Tumor necrosis factor-alpha (TNF-alpha) has been shown to enhance the synthesis of interleukin-6 (IL-6) and collagenase in human omental microvascular endothelial (HOME) cell (Mawatari, M., Kohno, K., Mizoguchi, H., Matsuda, T., Asoh, K., Van Damme, J. V., Welgus, H. G., and Kuwano, M. (1989) J. Immunol. 143, 1619-1627). In the present study, we have examined whether the TNF-alpha-induced synthesis of IL-6 or collagenase in HOME cells is mediated by an inducible growth factor. Among several growth factors examined, we found that the expression of basic fibroblast growth factor (bFGF) mRNA was the one most prominently enhanced when HOME cells were treated with TNF-alpha. The increase of bFGF mRNA by TNF-alpha in HOME cells was observed in both a dose- and time-dependent manner when assayed by Northern blot analysis. The induction of bFGF mRNA was observed by 3 h after incubation with TNF-alpha, and the maximal increase of 5-fold was obtained after 12 h of incubation with 100 units/ml TNF-alpha. Western blot analysis confirmed the enhanced synthesis of bFGF by TNF-alpha. Metabolic labeling and immunoprecipitation assays of bFGF showed that exposure to TNF-alpha enhanced secretion of bFGF into culture medium and also that TNF-alpha stimulated the production of bFGF molecules with molecular masses of 18, 21, and 22.5 kDa in HOME cells. TNF-alpha induced the expression of collagenase mRNA and IL-6 mRNA in HOME cells as well, and the coadministration of neutralizing anti-bFGF antibody almost completely blocked the effects of TNF-alpha. The treatment of HOME cells with exogenous bFGF significantly stimulated the expression of collagenase mRNA and IL-6 mRNA in HOME cells. Therefore, the biological effects of TNF-alpha on HOME cells may be mediated, at least in part, by TNF-alpha-induced bFGF.

Blotting, Northern↗
PubMed1991

Hepatocyte growth factor modulates migration and proliferation of human microvascular endothelial cells in culture.

Epidermal growth factor (EGF) induces tubular formation of cultured human omental microvascular endothelial (HOME) cells and EGF also stimulates cell migration as well as expression of tissue type plasminogen activator (t-PA). Here we studied the effects of hepatocyte growth factor (HGF) on cell proliferation, cell migration and expression of t-PA and other related genes. Migration of confluent HOME cells into the denuded space was stimulated by HGF after being wounded with razor blade, but at a reduced rate in comparison with EGF. HOME cells could be proliferated in response to exogenous 100 ng/ml of HGF at rates comparable to that of 20 ng/ml EGF. The chemotactic activity of HOME cells was significantly stimulated by HGF in a dose-dependent manner when assayed by Boyden chamber. HGF did not efficiently enhance expression of both the t-PA gene and a tissue inhibitor of metalloproteinase gene whereas it stimulated expression of plasminogen activator inhibitor-1. Our present study provides a new evidence that some of the biological effects of HGF on HOME cells in culture are similar to those of EGF.

Bilirubin↗
PubMed1991

Effects of transforming growth factor-beta released from gastric carcinoma cells on the contraction of collagen-matrix gels containing fibroblasts.

To investigate the mechanisms underlying contraction of the stomach wall in cases of gastric scirrhous carcinoma, we have developed an in vitro model for gastric cancer, in which both fibroblasts and gastric carcinoma cells are embedded within a collagen matrix. Gastric carcinoma cells of the scirrhous type (KATO-III) but not the nonscirrhous type (MKN-28) markedly enhanced the ability of human intestine, human lip, and mouse kidney fibroblasts to contract collagen gels. KATO-III cells released transforming growth factor-beta (TGF-beta) into culture media in an activated form, whereas the MKN-28 cells produced a latent form. The role of TGF-beta produced by gastric cancer cells from the scirrhous type was clarified by adding TGF-beta (receptor grade) into collagen gels embedded with fibroblasts, contraction being enhanced. Other growth factors tested, including transforming growth factor-alpha and epidermal growth factor, did not enhance the contraction of collagen gels containing embedded human and rodent fibroblasts. These results suggest that the activated form of TGF-beta released from gastric scirrhous carcinoma cells stimulates fibroblasts to contract the collagenous stroma of the stomach wall, which leads to the so-called "linitis plastica" stomach condition.

Adenocarcinoma, Scirrhous↗
PubMed1991

Prevention by interleukin-1 of intracisternally injected thyrotropin-releasing hormone (TRH)-induced gastric mucosal lesions in rats.

We have recently found that interleukin-1 (IL-1) acts in the central nervous system to potently inhibit gastric acid and pepsin secretion in rats. In the present study, we examined the effects of IL-1 on the development of gastric mucosal lesions induced by intracisternal (i.c.) thyrotropin-releasing hormone (TRH), a neuropeptide known to centrally stimulate gastric secretion. Pretreatment with i.c. injected IL-1 (10 ng/rat) significantly suppressed the severity of TRH-induced gastric erosions. On the other hand, the same dose of i.c. injected IL-1 failed to exert a cytoprotective action for the gastric mucosa against orally administered absolute ethanol. These results suggest that IL-1 has an anti-ulcer effect mainly through its inhibitory action on gastric secretion.

Animals↗
PubMed1991

Central nervous system action of basic fibroblast growth factor: inhibition of gastric acid and pepsin secretion.

To examine the effects of basic fibroblast growth factor (bFGF) on gastric secretion, the present study was carried out using pylorus-ligated rats. Intracisternally injected bFGF inhibited the secretion of both gastric acid and pepsin, and this gastric antisecretory action of bFGF was a dose-related response. On the other hand, the intraperitoneal injection of bFGF did not change gastric secretion. These results strongly suggested for the first time that bFGF, a growth factor that promotes the proliferation of various cell types, might also be a chemical messenger that is involved in the central regulation of gastric secretion. This biological action of bFGF may be considered as a novel nonmitogenic activity of this growth factor.

Animals↗
PubMed1991

[The relationship between TSH response to TRH and GH response to dopaminergic agents in patients with acromegaly].

The role of dopaminergic agents (DA) in the regulation of growth hormone (GH) secretion was investigated in patients with untreated acromegaly. TRH (0.5 mg iv), bromocriptine (Br) (2.5 mg orally) or L-Dopa (500 mg orally) loading tests were performed, and serum levels of TSH, GH and prolactin (PRL) were measured. Patients were defined as responders to TRH when peak TSH level after TRH test was higher than 5 microU/ml. Br or L-Dopa was considered to be effective when serum GH or PRL levels were suppressed more than 50% of the basal value. The patients were classified into large adenoma group with suprasellar extension or cisternal herniation (L group, n = 7) and intrasellar small adenoma group (S group, n = 11) which was further divided into TRH responder (Sr group, n = 4) and TRH non-responder with suppressed TSH (Ss group, n = 7). Br was effective in 7 or 100% of 7 patients in the Ss group but only in one or 25% of 4 patients in the Sr group. Br was also effective in 5 or 71% of 7 patients in the L group, although most of them were responders to TRH. Percent inhibition of serum GH levels by Br was significantly higher in the Ss group (82.3 +/- 12.3%, p less than 0.001) and in the L group (64.7 +/- 20.5%, p less than 0.05) compared with that in the Sr group (29.3 +/- 21.6%). Suppression of serum GH level by L-Dopa was also observed in the Ss group. In contrast to the difference in the response of GH, serum PRL level was equally suppressed by Br or L-Dopa in each group. Suppression of TSH by administration of exogenous T4 had no effect on the GH suppression effect of Br in the Sr group. Considering the dual effects of DA to enhance growth hormone-releasing hormone (GHRH) secretion in the hypothalamus and to suppress GH secretion in the pituitary gland, these findings suggest that the paradoxical effect of DA to suppress serum GH level is observed when the hypothalamo-pituitary axis is disturbed mechanically by large adenoma in the L group or functionally in the Ss group probably due to enhanced secretion of somatostatin which suppresses TSH secretion and impairs the effect of GHRH.

Acromegaly↗
PubMed1991

Cross-sectional area index of left ventricular myocardium as a risk factor influencing early and late postoperative survival in aortic regurgitation.

Late cardiogenic death after aortic valve replacement in aortic regurgitation is still a most important unresolved problem. We studied how the extent of cross-sectional area index (CSAI) relates to early and late cardiogenic deaths after aortic valve replacement (AVR) in aortic regurgitation with normal coronary artery. Forty-one patients were classified into two groups: Group I having CSAI greater than 20 cm2/m2 (18 patients), and Group II, in whom CSAI was less than 20 cm2/m2 (23 patients). All preoperative factors in patients with CSAI greater than or equal to 20 cm2/m2 showed poor values compared with patients with CSAI less than 20 cm2/m2 with a statistical difference of 63 +/- 6 versus 56 +/- 4% in cardiothoracic ratio, 72 +/- 9 versus 64 +/- 8 mm in diastolic dimension, 54 +/- 9 versus 43 +/- 7 mm in systolic dimension, 25 +/- 7 versus 32 +/- 6% in fractional shortening, 326 +/- 60 versus 209 +/- 63 ml/m2 in end-diastolic volume index, 177 +/- 52 versus 81 +/- 29 ml/m2 in end-systolic volume index, and 47 +/- 14 versus 58 +/- 5% in ejection fraction (mean +/- SD). In Group II, there were no postoperative cardiac deaths and no patient was subjected to intra-aortic balloon pumping (IABP). In contrast, in Group I, 17% died from postoperative low output syndrome and 33% were subjected to IABP. Concerning late deaths, there was no cardiac death in any CSAI patient with less than 20 cm2/m2; however, 22% of the patients with CSAI greater than or equal to 20 cm2/m2 died from cardiac causes.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗
PubMed1991

Tumor necrosis factor and epidermal growth factor modulate migration of human microvascular endothelial cells and production of tissue-type plasminogen activator and its inhibitor.

Epidermal growth factor (EGF) induces tubular formation of cultured human microvascular endothelial (HME) cells in the gel matrix containing collagen, and tumor necrosis factor (TNF) disrupts the tubular formation (Mawatari et al. (1989) J. Immunol. 143, 1619-1627). Here we studied the effects of EGF and TNF on endothelial cell migration and on the production of proteases. Confluent HME cells, when wounded with a razor blade, moved into the denuded space. This migration was stimulated by EGF and inhibited by TNF in this assay and in the Boyden chamber assay. Antibody against tissue-type plasminogen activator (t-PA) inhibited the EGF-stimulated cell migration in both assays by approximately 70%, but antibody against urokinase-type plasminogen activator (u-PA) could not inhibit its migration. Quantitative immunoreactive assays showed an approximately three- to fourfold increase of t-PA at 6 to 12 h after EGF addition, and TNF inhibited the production of t-PA by 50%. Northern blot analysis showed increased expression of t-PA mRNA by EGF alone in a time- and dose-dependent manner, whereas TNF alone inhibited its expression in a time- and dose-dependent manner. Northern blot analysis showed a significant increase of plasminogen activator inhibitor-1 (PAI-1) mRNA when EGF or TNF was present. Stimulation by EGF of cell migration of HME cells and its inhibition by TNF appear to be closely correlated with the cellular modulation of t-PA and PAI-1 activities.

Cell Movement↗
PubMed1991

The nucleotide sequence for a proline-activating domain of gramicidin S synthetase 2 gene from Bacillus brevis.

A fragment encoding proline-activating domain (grs 2-pro) of gramicidin S synthetase 2 (GS 2) was found in an 8.1-kilobase pairs (kb) DNA fragment of Bacillus brevis Nagano, which contained the full length of GS 1 gene (grs 1). The clones designated GS719 and GS708, which expressed gramicidin S synthetase 1, were elucidated to express immunoreactive proteins to GS 2 antibodies with approximate molecular weights of 115,000, 105,000 (GS719), and 110,000 (GS708). The partial purification of the gene products of these clones was carried out using DEAE-Sepharose CL-6B column chromatography. The immunoreactive proteins to GS 2 antibodies were separated from gramicidin S synthetase 1 protein and had specific proline-dependent ATP-32PPi exchange activity. The nucleotide sequence for the proline-activating domain in the 8.1-kb insert was determined. This fragment was 2,879 base pairs long, and encoded 959 amino acids. The calculated molecular weight of 111,671 was consistent with the apparent molecular weight of 115,000 found in SDS-PAGE of the immunoreactive products to GS 2 antibodies. The open reading frame for this protein followed grs 1 gene, though two were separated by a 73-base pair noncoding sequence, and remained open to the end.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Isomerases↗
PubMed1991

Follow-up study of camp marathon group psychotherapy for adolescents with emotional disturbances.

Every summer since 1972, the Department of Psychiatry at Fukuoka University has been holding the Camp Marathon Group Psychotherapy (MGP) for adolescents with emotional disturbances. This time we conducted a follow-up survey on 114 camp attendees from 1978 to 1985. Questionnaires were mailed out and we received 56 replies, that is a response rate of 49.1%. The average observation period of the follow-up was 4 years. The results were as follows: Thirty-six cases or 64.3% were making satisfactory progress at the time of the survey. Eight or 14.3% showed no change or showed worsening conditions. Seven or 12.5% cases developed into schizophrenia. Based on these results, we studied roughly what role MGP plays in the therapy of adolescents with emotional disturbances.

Adolescent↗