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Biomedical subjects

J Hayashi

Publications and source records attributed to J Hayashi.

At least 307 records · Page 17Linked to original sources
PubMed1993

[Flow characteristics and responses to vasoactive drugs in canine gastroepiploic artery].

We studied flow characteristics and response to norepinephrine, Chlorpromazine and gastrin in 22 canine gastroepiploic artery (GEA) recirculation model. The GEA flow was obtained by a drip for a minute, opening the end of pedicle GEA. Furthermore, aortic flow and celiac arterial flow were measured by magnetic flow probe. The administration of chlorpromazine, vagostigumine, and gastrin induced a increase in both celiac arterial flow and pedicle GEA graft flow. Especially, the administration of gastrin induced significant increase in GEA flow and celiac arterial flow. Furthermore, adding norepinephrine step-wisely, the GEA flow increased remarkably, in spite of decrease of celiac arterial flow. This response was caused from difference in vascular resistance among celiac arterial branches. Therefore, the pedicle GEA graft has homogenous response as same as intact GEA that perfuses stomach, because its flow was affected by adrenergic and parasympathetic agent, alpha-blocker and gastric hormone.

Animals↗
PubMed1992

Sexual transmission of hepatitis C virus among female prostitutes and patients with sexually transmitted diseases in Fukuoka, Kyushu, Japan.

The authors investigated the prevalence of antibody to hepatitis C virus (anti-HCV) in 404 female prostitutes, 428 clinic patients with a history of at least one episode of sexually transmitted disease, and 8,944 blood donors who served as the controls. All subjects were Japanese, and all studies were carried out in Fukuoka, Kyushu, Japan, in 1989. The prevalence of anti-HCV was significantly higher in the prostitutes (6.2%), in the female patients with sexually transmitted diseases (6.1%), and in the male patients with sexually transmitted diseases (2.9%) than in the controls (1.5%). Prevalence of anti-HCV increased with age in prostitutes and in the controls. The prevalence of anti-HCV in those who had been involved in prostitution for 1 year or more (8.1%) was higher than in those who had been involved in prostitution for less than 1 year (1.4%), but the difference was not statistically significant. One of the 152 anti-HCV negative prostitutes seroconverted between 1 and 2 years later. Among the subjects with sexually transmitted diseases, patients with a history of at least one episode of syphilis had a significantly higher prevalence of anti-HCV (4.4%) than the controls. Patients with acute urethritis and cervicitis also showed a high prevalence of anti-HCV (3.6% and 6.7%, respectively). These data support the possibility of sexual transmission of hepatitis C virus.

Adolescent↗
PubMed1992

Effect of testosterone on the growth properties and on epidermal growth factor receptor expression in the teratoma-derived tumorigenic cell line 1246-3A.

1246-3A is an insulin-independent tumorigenic cell line isolated from the C3H mouse teratoma-derived adipogenic cell line 1246. In the present paper, we have demonstrated that testosterone inhibits the in vivo tumorigenic properties of the 1246-3A cells. Castrated male mice receiving injections of 1246-3A cells developed larger tumors at a higher frequency than sham-operated animals. Administration of testosterone to castrated male mice resulted in a dramatic decrease in tumor development. In vitro studies indicated that testosterone inhibited by 50% the proliferation of the 1246-3A cells in culture. However, growth inhibition was observed only if the cells had been cultivated in the presence of testosterone for at least 4 days. In contrast, testosterone had little effect on the proliferation of the parent cell line 1246. Binding of several polypeptide growth factors was examined in cells cultivated in the absence and in the presence of testosterone. Testosterone increased 125I-EGF specific binding to 1246-3A cells. Scatchard analysis of EGF binding indicated that testosterone treatment induced a 2.4-fold increase in the number of cell surface EGF binding sites. This was accompanied by an increase in the intensity of cross-linked EGF receptors on the cells treated with testosterone. In addition, 1246-3A cells cultivated for 9 days in the presence of testosterone displayed a 10-fold increase in the level of EGF receptor mRNA when compared to 1246-3A cells maintained in its absence. Similar to its action on cell proliferation, the increase in EGF receptor number and mRNA expression was observed mainly if 1246-3A cells had been exposed to testosterone for 9 days. The data presented in this paper demonstrate that both in vivo and in vitro, testosterone induces in the teratoma-derived 1246-3A cell line phenotypic changes such as growth inhibition and modulation of EGF receptor expression.

Animals↗
PubMed1992

Recovery of the missing tumorigenicity in mitochondrial DNA-less HeLa cells by introduction of mitochondrial DNA from normal human cells.

The role of mitochondrial DNA (mtDNA) in the expression of the transformed phenotype was examined using mtDNA-less HeLa cells. Complete depletion of mtDNA and its products in the mtDNA-less HeLa cell line, EB8, was confirmed by Southern blot analysis and by [35S]methionine labeling of mitochondrially synthesized polypeptides. The tumorigenicity of the EB8 cells was assayed by inoculation of 1 x 10(7) cells subcutaneously into the backs of nude mice. The results showed that the tumorigenicity of HeLa cells was lost in good correspondence with the loss of mtDNA. However, the growth of EB8 cells in culture was very poor compared with that of HeLa cells, indicating that the apparent loss of tumorigenicity in EB8 cells could possibly be due to poor growth of the cells. Introduction of mtDNA from normal human fibroblasts into EB8 cells restored both the missing tumorigenicity and growth of the EB8 cells. These observations could be interpreted to show that mtDNA is required for expression of tumorigenicity, but that mutational changes of the mtDNA are not required for modulation of the phenotype in our experiments.

Animals↗
PubMed1992

Hepatitis C virus detection is facilitated by the combined use of c100 protein and GOR epitope.

Assay for the antibody to the c100 protein (anti-c100) lacks sensitivity in terms of detection of hepatitis C virus (HCV) in all samples. The author used anti-c100 and antibody to the GOR epitope (anti-GOR) by the enzyme-linked immunosorbent assay to examine 524 patients with chronic liver disease and 682 volunteer blood donors in Fukuoka, Japan. The prevalence of HCV infection, as revealed by the presence of anti-c100 and/or anti-GOR, was 3.9% in 540 volunteer blood donors, 12.7% in 142 volunteers with abnormal liver function, 7.4% in 135 patients with HBsAg-positive liver disease and 89.5% in 389 patients with non-A, non-B (NANB) liver disease. These results show a higher prevalence than demonstrated only by the anti-c100 in NANB liver disease patients (82.5%, P < 0.01). The concurrence of anti-c100 and anti-GOR in subjects with HCV infection was 23.8% in 21 volunteer blood donors, 44.4% in 18 volunteers with abnormal liver function and 61.2% in 348 NANB liver disease patients. The concurrence seems to increase with deterioration of liver function. We concluded that combination assay for anti-c100 and anti-GOR demonstrated a more accurate prevalence of HCV infection than single assay for anti-c100 among NANB liver disease patients, and that the presence of anti-GOR plays a role in liver disease in anti-HCV-positive subjects.

Adolescent↗
PubMed1992

Mechanical circulatory assist using heparin-coated tube and roller pump system.

We have invented a mechanical circulatory assist system that uses a heparin-coated tube and a roller pump. Experimental left heart bypass was performed on 13 mongrel dogs for 24 hours without systemic heparinization. There were no significant changes in coagulation variables during the experiment, and pathological examination of internal organs after bypass revealed no evidence of thromboembolism. We applied this assist system to 13 patients who could not be weaned from cardiopulmonary bypass after an open heart operation. Left heart bypass was performed on 7 patients, right heart bypass on 1 patient, combined left and right heart bypass on 2, and venoarterial bypass without oxygenation on 3. Duration of support ranged from 5 hours to 21 days, and the pump flow rate ranged from 0.8 to 3.2 L/min. Eight patients were successfully weaned from this support, and 6 were discharged from the hospital. Examination of the tubes in the assist system revealed excellent antithrombogenicity for at least 3 days without systemic heparinization. There was no evidence of thromboembolism in brain, kidneys, lungs, or other organs. Because of its simplicity and antithrombogenicity, this mechanical assist system is beneficial for patients who cannot be weaned from cardiopulmonary bypass after open heart operations.

Adult↗
PubMed1992

Limited vertical skin incision for median sternotomy.

The cosmetic deformity of the vertical skin incision for median sternotomy was decreased by using a mechanical traction system to increase exposure at the superior margin of a shorter wound. The limited vertical skin incision did not impede technical surgical maneuvers and produced a scar that was more acceptable than submammary incision or right anterior thoracotomy. The limited skin incision is especially useful in young women with congenital heart disease.

Adolescent↗
PubMed1992

Myocardial protection of neonatal heart by cardioplegic solution with recombinant human superoxide dismutase.

The effectiveness of high-potassium cardioplegic solution in the neonatal heart remains controversial. Our previous study indicated that the protection afforded by a cardioplegic solution was inadequate in the neonatal heart. On the hypothesis that oxyradicals were responsible for the ineffectiveness of cardioplegic solution in neonatal heart, the effects of a cardioplegic solution (a modified St. Thomas' Hospital cardioplegic solution) with recombinant human superoxide dismutase on the isolated perfused neonatal guinea pig hearts (within 2 days after delivery, body weight of 60 to 120 g) were studied in comparison with those on the adult hearts (6 to 8 weeks after delivery, body weight of 300 to 500 g). After arrest induced by modified St. Thomas' Hospital cardioplegic solution, hearts were subjected to 120 min of ischemia at 20 degrees C, during which time the cardioplegic solution was injected every 30 minutes. Then the heart was reperfused for 60 minutes at 37 degrees C. Under this condition, the left ventricular developed pressure recovered to 84.4% +/- 4.0% of the preischemic value in the adult heart, whereas the recovery was only 68.1% +/- 3.1% in the neonatal heart. Thiobarbituric acid-reactive substance level, a parameter of lipid peroxidation by oxyradicals, significantly increased during ischemic arrest both in the adult and neonatal heart. However, the increase was much greater in the neonatal heart than in the adult. Cardioplegia with recombinant human superoxide dismutase (300 and 1,000 U/mL) significantly inhibited this accumulation of thiobarbituric acid-reactive substance in the neonatal heart; at 1,000 U/mL, the myocardial function of the reperfused neonatal heart recovered to the level of the adult heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1992

The effects of breastfeeding and presence of antibody to p40tax protein of human T cell lymphotropic virus type-I on mother to child transmission.

We examined the effects of various factors, including duration of breastfeeding, the status of mother's anti-p40tax, and titre of mother's anti-human T cell lymphototropic virus type-I (HTLV-I) on mother to child transmission of HTLV-I in 76 HTLV-I carrier mothers and 175 of their children. The overall prevalence of anti-HTLV-I among children was 16.0%. The prevalence of anti-HTLV-I among children breastfed for over 3 months was significantly higher (27.6%) than that of those breastfed for under 3 months (5.1%; P = 0.012). Of the 78 bottle-fed children, 10 (12.8%) were positive for anti-HTLV-I. In the children breastfed for over 3 months, the prevalence of anti-HTLV-I among 37 children of anti-p40tax positive mothers was 37.8% and that of 21 children of anti-p40tax negative mothers was 9.5%, a significant difference (P = 0.044). These data suggest that about 13% of bottle-fed children born to carrier mothers are infected with HTLV-I by routes other than breast milk, and that the mother's anti-p40tax can serve as a marker of infectivity of HTLV-I in the case of breastfeeding for over 3 months.

Adolescent↗
PubMed1992

[Evaluation of micro particle enzyme immunoassay (MEIA) for the demonstration of antibody to hepatitis B surface antigen].

A fully automated microparticle enzyme immunoassay (IMx AUSAB, Abbott) has been recently introduced for the detection of the presence of antibody to hepatitis B surface antigen (anti-HBs). The present trial was carried out to determine the feasibility of using the IMx AUSAB with sera and plasma, and for comparison with RIA (AUSAB, Abbott) and EIA (AUSAB EIA, Abbott). According to the kinds of vaccines used and locations of residents, the subjects were divided into six groups. Results obtained were as follows; In the test of 642 sera from 446 vaccines and 196 other inhabitants of Okinawa and Miyazaki prefectures, 388 (87.0%) were found positive for anti-HBs using IMx, 392 (87.9%) with RIA and 359 (80.5%) with EIA. Among those vaccinated with recombinant vaccines, 96.6% were found positive with IMx, 96.2% with RIA and 89.4% with EIA. Among subject vaccinated with plasma derived vaccines, 72.9% were found positive with IMx, 75.7% with RIA, and 68.5% EIA. Quantitative agreement between IMx and RIA among the six groups gave linear correlation coefficients ranging from 0.459 to 0.821. In the group vaccinated with the recombinant vaccine by K company (r = 0.459), anti-HBs was confirmed in many sera by IMx compared to that confirmed by RIA and EIA. In addition, anti-HBs was assayed within one hour by IMx and the procedure was simplified by autoanalyser equipped for this method. The results indicate that the sensitivity of IMx is equal to that of RIA and more than that of EIA, and that quantitative linear correlations were obtained between IMx and RIA, and IMx and EIA.

Hepatitis B Antibodies↗
PubMed1992

[Evaluation of micro particle enzyme immunoassay technique (MEIA)-IMx for the detection of antibody to hepatitis A virus].

A new micro particle enzyme immunoassay technique (MEIA, IMx HAVAB, Abbott) has been recently introduced for the detection of antibody to hepatitis A virus (anti-HA). To evaluate the feasibility of the IMx HAVAB, we carried out comparison tests between MEIA, RIA and EIA. Furthermore, we investigated the prevalence of anti-HA in Fukuoka City and Yonaguni Island, Okinawa, Japan using this method. Results obtained were as follows: In the test of 514 sera, 254 (49.0%) were positive by the three methods, and the remaining 260 (50.6%) were negative by the three methods. Examination of diluted sera using IMx revealed that IMx can be used as efficiently as RIA and EIA. Quantitative linear correlations were found between IMx and RIA (r = 0.973), and IMx and EIA (r = 0.969). Anti-HA was assayed within 45 minutes by IMx, and the procedure was simple because of the auto analyser used in this method. On Yonaguni Island, a significant decrease in the overall prevalence of anti-HA from 75.2% in 1980 to 61.1%, in 1990 (p less than 0.05) was found, the prevalence of anti-HA on Yonaguni Island in 1990 was significantly higher than in Fukuoka City (p less than 0.001). These results indicate that the sensitivity of IMx is equivalent to those of RIA and EIA, that it is easier to use than either RIA or EIA and that hepatitis A virus infection in Okinawa, has significantly decreased during the past 10 years, but is still significantly more frequent than in Fukuoka City.

Adolescent↗
PubMed1992

Role of sympathetic nerve inhibition in the vasodepressor effect of bromocriptine in normotensive and hypertensive rats.

This study aimed to elucidate the mechanism of the hypotensive effect of bromocriptine (BRC), and to investigate whether or not the effects of BRC on the sympathetic nervous system are altered in hypertension. BRC was administered intravenously to normotensive and spontaneously hypertensive rats (SHR). It elicited hypotensive effects dose-dependently in urethane-anaesthetized normotensive rats, an effect which was antagonized with metoclopramide. Pretreatment with intravenous hexamethonium attenuated the hypotensive effect of BRC. BRC decreased plasma norepinephrine (NE) without inhibiting the sympathetic nerve spikes recorded from the postganglionic sympathetic nerve bundle. The hypotensive effect of BRC was significantly greater in SHR than in Wistar Kyoto Rats (WKY). Decrease in NE by BRC was also significantly greater in SHR than in WKY. These results suggest that the hypotensive effect of BRC is induced by suppression of NE release, not by inhibition of sympathetic nerve spikes, and that the dopaminergic presynaptic inhibition is attenuated in SHR.

Animals↗
PubMed1992

[Protective effects of naftidrofuryl oxalate against hypoxia-induced death].

To analyze the effects of naftidrofuryl oxalate (LS-121) on the central nervous system exposed to critical hypoxia, survival duration was employed as a parameter of the protective effects of the drug against hypoxia-induced death. In the control group (no drug administration), the electroencephalogram (EEG) was flattened promptly after changing to hypoxia from aerobic conditions, and it was impossible to recognize precisely what time the EEG disappeared because of vigorous body movements. Arterial blood pressure (BP) was clearly recognized, and rats never recovered after BP decreased to 0 mmHg, although the electrocardiogram (ECG) was still recorded. Thus, survival duration recognized by measuring the time from the onset of hypoxia to the time when BP became 0 mmHg was considered to be a good indicator. After LS-121 (10 mg/kg) administration, survival duration was significantly prolonged compared to the control. Combination therapy of LS-121 (25 mg/kg) and bifemelane hydrochloride (BI) (25 mg/kg) also revealed the prolongation of survival duration. Neither idebenone (10 mg/kg) nor nicergoline (10 mg/kg) showed significant changes in survival duration. These findings suggest that LS-121, either with or without BI, could improve cerebrovascular disorders induced by hypoxia.

Animals↗
PubMed1992

Calcium suppresses central angiotensin II pressor response less in SHR.

To determine whether calcium alters central cardiovascular regulation, cardiovascular responses to intracerebroventricular (ICV) injection of calcium were recorded in conscious Wistar rats. Calcium injection consistently produced dose-dependent decreases in mean parterial pressure and heart rate. Pretreatment with a calcium channel blocker, diltiazem, attenuated cardiovascular responses to calcium. Decreases in plasma norepinephrine indicated the contribution of sympatho-inhibition to vasodepression by calcium. Preceding calcium injection reduced pressor responses to ICV-injected angiotensin II. These findings suggest that there is a pharmacological interaction between calcium and angiotensin II in the central nervous system. In spontaneously hypertensive rats (SHR), cardiovascular responses to calcium was larger than Wistar Kyoto rats (WKY). By contrast, calcium reduced pressor responses to angiotensin II only in WKY but not in SHR. Because the central interaction between calcium and angiotensin II has been different in SHR, our results imply that this difference may be related to the maintenance of high blood pressure in SHR.

Angiotensin II↗
PubMed1992

Stimulation of prostaglandin production in rat thymic epithelial cells by protein kinase C mediated activation of phospholipase A2.

Tumor promoter (phorbol-12-myristate-13-acetate:PMA) stimulates the production of prostaglandin E2 (PGE2) in a dose- and time-dependent manner in cloned rat thymic epithelial cells, TEA3A1. This stimulation of PGE2 production by PMA was blocked by pretreatment of cells with protein kinase C (PKC) inhibitor staurosporin and was abolished in PKC down modulated cells. PMA treatment significantly stimulated the release of arachidonic acid from the cells, but had no effect on arachidonic acid incorporation and on cyclooxygenase enzymatic activity of the cells. These results indicate that PMA stimulates PGE2 production through PKC mediated activation of phospholipase A2 (PLA2) in thymic epithelial cells.

Animals↗
PubMed1992

[Late postoperative outcome of plastic operation versus valve replacement for mitral regurgitation].

Between January 1980 and August 1991, 99 patients underwent operation for mitral valve regurgitation (MR). The ages of the patients ranged from 12 to 67 years, (49.4 +/- 11.9 years), and there were 39 males and 60 females. Pathological cause of regurgitation, which was determined by intraoperative inspection and histological findings of excised leaflets, was rheumatic in 46, degenerative in 38, infective endocarditis in 9, ischemic in 4 and unknown in 2 patients. Cardiac rhythm was atrial fibrillation in 73, normal sinus rhythm in 24 and junctional rhythm in 2 patients. Our principles for valve repair were (1) excision of responsible segment and repair for prolapsed leaflet due to torn chordae, (2) shortening of elongated chordae, (3) annuloplasty, and (4) repair of perforated leaflet. Finally, 19 patients endured plastic operation, and 80 patients underwent prosthetic valve replacement. The rate of plastic procedure was 62.5% (10/16) in degenerative MR with mural chordal lesions, 42.9% (3/7) in rheumatic MR without stenosis, 22.2% (2/9) in infective endocarditis and 100% (2/2) in MR with unknown etiology. Mitral valve repair was failed both in rheumatic MR associated with stenosis (39 patients) and in ischemic MR (4 patients). A ten-year survival rate after operation was 92.2 +/- 3.1% in patients with valve replacement and 83.6 +/- 10.0% with valve repair (N.S.), and a proportion of event-free survival in patients with valve replacement was similar to valve. Late postoperative cardiac catheterization revealed decreased left ventricular volume indices and increased left ventricular end-systolic stress/volume ratio in both groups compared to preoperative values, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗