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Biomedical subjects

J Hayashi

Publications and source records attributed to J Hayashi.

At least 343 records · Page 19Linked to original sources
PubMed1991

Enhanced norepinephrine release in hypothalamus from locus coeruleus in SHR.

The hypothesis that a functional projection from the locus coeruleus (LC) to the posterior hypothalamus contributes to the development of hypertension in SHR, was tested by measuring norepinephrine (NE) in the posterior hypothalamus by brain dialysis after injections of L-glutamate (L-glu) into LC. L-glu elicited a prolonged elevation of blood pressure in both SHR and WKY. Pressor effects were significantly larger in SHR than in WKY. Extracellular NE in the posterior hypothalamus increased after LC stimulation; NE release was significantly higher in SHR than in WKY. Injections of 6-hydroxydopamine (6-OHDA) into posterior hypothalamus lowered the resting blood pressure and attenuated the pressor responses to L-glu injections into the LC in SHR. These findings suggest that the LC projects functionally to the posterior hypothalamus and that the projection can contribute to the development of hypertension in SHR.

Animals↗
PubMed1991

Multilineage antigen expression and possible autocrine secretion of an interleukin 1 by Ph1-positive leukemic cell line KOPM-28.

A newly established Ph1-positive cell line, KOPM-28 was analyzed for immunological phenotype and the release of biological substance. The surface marker analysis revealed myelomonocytoid antigens, erythroid antigens and megakaryocyte-platelet antigens. Also, the cells could be induced for hemoglobin synthesis by the addition of hemin. The conditioned medium of this cell line showed the presence of interleukin 1 (IL-1) activity but not interleukin 2. Exogenous IL-1 and the conditioned medium stimulated the DNA synthesis of the cells themselves. Consequently, the yield substance works on the growth of original cells as an autocrine fashion, and might act on other normal cells as a paracrine factor.

Antigens, Neoplasm↗
PubMed1991

Hepatitis C virus is a more likely cause of chronic liver disease in the Japanese population than hepatitis B virus.

508 Japanese patients with chronic liver disease, including chronic hepatitis, cirrhosis and hepatocellular carcinoma, and 500 controls matched for sex and age were studied. Antibody to hepatitis C virus (anti-HCV) alone was found in 233 (45.9%) patients and hepatitis B surface antigen (HBsAg) alone was present in 128 (25.2%) patients. Both anti-HCV and HBsAg were present in 18 (3.5%) patients. Anti-HCV was found in 8 (1.6%) controls and HBsAg was present in 4 (0.8%) controls. The prevalence of anti-HCV alone was 36.9% in chronic hepatitis, 49.0% in cirrhosis and 67.0% in hepatocellular carcinoma, respectively. The prevalence of anti-HCV increased with the progress of severity of liver disease. Anti-HCV was more prevalent than HBsAg both in cirrhosis and hepatocellular carcinoma (p less than 0.001). The prevalence of anti-HCV increased with age. Among patients under age 39 years, HBsAg was detected more often than anti-HCV, however, in those over age 50 years, anti-HCV was detected more often than HBsAg (p less than 0.001). It would appear that hepatitis C virus more than hepatitis B virus is a prominent cause of chronic liver disease among Japanese patients.

Adolescent↗
PubMed1991

[Surgical treatment of ascending aortic lesions associated with aortic insufficiency].

Twenty four patients underwent surgical treatment for ascending aortic lesions with aortic insufficiency at our institution. There were 16 male and 8 female patients from 12 to 67 years. Of 24 patients, 11 patients had Marfan's syndrome, and were younger at the time of operation. Three types of operative procedure were performed, that is, aortic valve replacement (AVR) and supracoronary graft replacement in 4 patients, AVR and covering the aneurysm of ascending aorta in 9, and composite graft replacement of the aortic valve and ascending aorta in 11. One patient died of perioperative myocardial infarction within 30 days after operation (early mortality rate, 4.2%). Another 5 patients died during the initial hospitalization, but no deaths were related to operative procedures. There was a total of 5 (27.8%) late deaths among the 18 patients follow-up with 5 and 10 years survival rate, 60.8%, 52.1%, respectively. Four of five patients was the cases with Marfan's syndrome. There were no statistically significant differences among three different procedures, but all patients who underwent composite graft replacement and left the hospital alive are doing well.

Adolescent↗
PubMed1991

[Surgical management of valve replacement in children].

From 1965 to 1990, 49 valve replacements were performed on 43 patients under the age of 15. Mitral valve replacements were performed on 21 patients, and re-replacements were done on 4 of them afterwards. In the first 9 mitral valve replacements before 1974, Starr-Edwards (S-E) ball valves were used. Five of these patients died in the hospital (early mortality rate was 56%). Since 1975, bioprosthetic valves were used in three cases, but all of these valves ceased to function due to primary tissue failure (PTF) within 3 years. Consequently, SJM valves are now used as a first choice. Ten aortic valve replacements were performed on 9 patients with the results of one early death, two late deaths, and one late re-operation. Tricuspid valve replacements were performed on 11 patients, 5 of whom utilized S-E ball valves. Three of the five patients died in the hospital. One patient was re-operated on, swapping the S-E ball valve for the SJM valve. SJM valves were used primarily in 2 patients, and bioprosthetic valves in 4. Two patients died, one with a SJM valve, and the other with a bioprosthetic valve. Two pulmonary valve replacements were performed, one employing a SJM valve, the other a bioprosthetic valve. Two adult patients with SJM valve in the right side of the heart had thrombotic complications, though the patients with bioprosthetic valves had none. Atrioventricular valve replacements were performed on 5 patients under the age of 3, but all of them died.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[A modified translocation technique for recurrent periannular endocarditis after aortic valve replacement].

We reported a patient of 46-year-old man, who had undergone reinforced aortic valve replacement using a composite Björk-Shiley prosthesis for infective endocarditis on April 13, 1988. Because of recurrent periannular endocarditis and periprosthetic dehiscence, reoperation was undertaken eighteen months after the initial operation. Following debridement, a composite Dacron vascular prosthesis with a St. Jude Medical valve and two saphenous vein grafts were transposed in the ascending aorta. The operative procedures were entirely smooth. A modified Danielson's technique may be adequate for recurrent periannular endocarditis which make orthotopic re-replacement impossible in most cases.

Aortic Valve↗
PubMed1990

Effects of ethidium bromide treatment of mouse cells on expression and assembly of nuclear-coded subunits of complexes involved in the oxidative phosphorylation.

Using mouse cell lines 5P and 5PEr (ethidium bromide-resistant derivative of 5P), we examined the influence of blocking expression of mitochondrial-gene products with ethidium bromide on the expression and assemblies of nuclear-coded subunits of the complexes involved in the oxidative phosphorylation. The results suggest that in the absence of mitochondrial-coded products, the expressions of subunit VIc of complex IV and beta-subunit of F1-ATPase are not affected, but that most nuclear-coded subunits other than alpha- and beta-subunits of F1-ATPase cannot be assembled nor inserted into the inner membrane.

Actins↗
PubMed1990

[A case of pheochromocytoma with an AMI-like ECG change corrected by an alpha-blocking agent].

A 59 year-old housewife was admitted to the emergency service with a sudden onset of chest pain and nausea. Initially she was treated as an acute myocardial infarction, but conventional treatments were not effective, and she was sent to our hospital for further evaluation. Her ECG showed several abnormal findings including T-wave inversion, atrial flutter, QT-time prolongation, ST-segment depression or elevation, and frequent ventricular ectopic beats. The echocardiogram, 201thallium scintigram and coronary angiography were almost normal. Both urinary and plasma levels of catecholamines were remarkably increased, and the plasma epinephrine was extremely high during attacks. Abdominal echotomography and CT-scanning showed a large left adrenal tumor. The 131MIBG scintiscan revealed a high accumulation in this tumor. Then the patient was diagnosed as having pheochromocytoma and catecholamine-induced myocarditis. The administration of phentolamine (10 mg) normalized the inversion of T-wave and the high blood pressure. But when propranolol (2 mg) was administrated in addition to phentolamine, the ECG showed a biphasic low T-wave change. According to these phenomena, we supposed that the alpha-adrenergic receptor was involved in the development of the ST-T changes of the ECG, and the alpha-adrenergic receptor of this patient might be sensitive under excessive catecholamines, according to the inhibition of the beta-receptor by propranolol.

Adrenal Gland Neoplasms↗
PubMed1990

Frequency of concurrence of hepatitis B surface antigen and antibody in a large number of carriers in Okinawa, Japan.

A large number of chronic hepatitis B surface antigen (HBsAg) carriers in Okinawa, Japan were tested for antibody to HBsAg (anti-HBs), by both radioimmunoassay and enzyme immunoassay methods. Concurrence of HBsAg and anti-HBs was found in 166 (26.1%). We found no clear predominance of either liver damage or hepatitis B e antigen (HBeAg) in the concurrent carriers studied. Antibody to pre-S2 antigen (anti-pre-S2) was detected in 16 (9.6%) of 166 subjects with concurrent markers, 15 of these 16 carriers were positive for antibody to HBeAg (anti-HBe). Anti-pre-S2 was correlated with anti-HBe rather than with anti-HBs. The distribution of HBsAg subtypes among carriers determined to have subtypes was 76.7% adw, 22.0% adr, 0.2% ayr, 0.9% adwr, and 0.2% adyr. The distribution of anti-HBs subtypes among concurrent carriers was 51.5% anti-r, 21.4% anti-w, 15.5% anti-d, and 10.7% anti-y. Concurrent carriers had HBsAg of one subtype and heterotypic anti-HBs. Because the HBsAg subtype ay is rare in this area, it is hard to believe that the concurrent carriers with anti-y were infected with hepatitis B virus of which the HBsAg subtype was ay. A dual infection was highly unlikely. It seems that some of the concurrent carriers correlate with compound subtypes adwr and adyr.

Carrier State↗
PubMed1990

Prevalence of IgM anti-HBc among HBsAg carriers in Okinawa, Japan.

To evaluate the presence of IgM antibody to hepatitis B core antigen (IgM anti-HBc) in hepatitis B surface antigen (HBsAg) carriers, serial serum specimens of 698 carriers in Okinawa, Japan, from infants to adults, were studied by radioimmunoassay. IgM anti-HBc was detected in 7.6% of these carriers, with no difference between the sexes. The prevalence of IgM anti-HBc was higher in the age groups 0-9, 50-59 and over 60 than in the age group 20-29 and 30-39 years. In hepatitis B e antigen (HBeAg) positive carriers, the prevalence of IgM anti-HBc was 15.4%, a value significantly higher than in the HBeAg-negative carriers at 6.6%. In carriers with liver damage, the prevalence of IgM anti-HBc was 33.3%, a level significantly higher than the 6.3% in carriers without liver damage. However, IgM anti-HBc was detected in 34 carriers with neither HBeAg nor liver damage. These carriers are being closely followed. We discussed the presence of IgM anti-HBc in association with HBeAg or liver damage. The presence of IgM anti-HBc among HBsAg carriers was closely associated with liver damage.

Adolescent↗
PubMed1990

Thymocytes stimulate metabolism of arachidonic acid in rat thymic epithelial cells.

Arachidonic acid metabolites play an important role in the development of T cells in the thymus. In the normal animal, prostaglandin levels in the thymus are significantly higher than in plasma. Herein, we have studied the regulation of arachidonic acid metabolism using the thymic endocrine epithelial cell line, TEA3A1, and thymocytes. We have found that TEA3A1 cells, but not thymocytes, produced prostaglandins and thromboxanes. We have also found that thymocytes could stimulate the production of arachidonic acid metabolites in TEA3A1 cells when both cells were cocultured. The strongest stimulation was observed when TEA3A1 cells were cocultured with thymocyte subpopulations either negative for OX8 or W3/25 functional surface markers (either double-negative or single-positive thymocytes). Furthermore, cell-cell contact seems to be absolutely required for the activation of arachidonic acid metabolism in TEA3A1 cells. The study presented here describes the existence of a novel regulatory mechanism of arachidonic acid metabolism which may play an important role in the development of T cells in the thymus.

Animals↗
PubMed1990

Culture and characterization of thymic epithelium from autoimmune NZB and NZB/W mice.

Autoimmune NZB and NZB/W mice display early abnormalities in thymus histology, T cell development, and mature T cell function. Abnormalities in the subcapsular/medullary thymic epithelium (TE) can also be inferred from the early disappearance of thymulin from NZB. It has also been reported that NZB thymic epithelial cells do not grow in culture conditions that support the growth of these cells from other strains of mice. In order to study the contribution of TE to the abnormal T cell development and function in NZB and NZB/W mice, we have devised a culture system which supports the growth of TE cells from these mice. The method involves the use of culture vessels coated with extracellular matrix produced by a rat thymic epithelial cell line. TEA3A1, and selective low-calcium, low-serum medium. In addition TEA3A1 cells have been used as an antigen to generate monoclonal antibodies specific for subcapsular/medullary TE. These antibodies, as well as others already available, have been used to show that the culture conditions described here select for cells displaying subcapsular/medullary TE markers, whereas markers for cortical TE and macrophages are absent.

Animals↗
PubMed1990

Clonidine abolishes exaggerated pressor responses to shaker stress in spontaneously hypertensive rats.

To determine whether clonidine would attenuate exaggerated pressor responses to stress in spontaneously hypertensive rats (SHR), pressor responses to shaker stress were recorded following intracerebroventricular (icv) injections of clonidine in conscious SHR. Pressor responses to shaker stress were significantly larger in SHR than in Wistar-Kyoto rats (WKY). Increased sympathetic nerve responses to shaker stress were also significantly greater in SHR than in WKY. Exaggerated pressor responses in SHR were partly attenuated by adrenalectomy and abolished by clonidine (icv). By contrast, 1-Sar,8-Ile angiotensin II (icv) was ineffective. These findings suggest that in SHR, the alpha-adrenergic system in the brain may contribute to exaggerated pressor responses to shaker stress, but not the brain renin-angiotensin system.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1990

Marked decrease of hepatitis B virus infection among children in Okinawa, Japan.

During the period 1980-1989 in Okinawa, Japan, serologic markers of hepatitis B infection (hepatitis B surface antigen; HBsAg, antibody to hepatitis B core antigen; anti-HBc) were investigated in nursery school children (1-4 years of age). Prevalences of HBsAg were 1.1-1.5% in the period from 1980-1984, but decreased to under 1.0% in the period from 1985. In 1989 there were two carriers in nursery schools, both born in 1985 or fathers who were HBsAg carriers. Prevalences of anti-HBc were 3.3-7.1% in the period from 1980-1983 with a decrease to 0.5% by 1988. Since hepatitis B vaccine was available for neonates whose mothers were HBsAg carriers with hepatitis Be antigen (HBeAg) and for nursery school children in 1983, hepatitis B virus infection among nursery school children and HBsAg carriers due to transmission from mother-to-child were markedly reduced. This strategy for immunization is useful in endemic areas. Immunization for children whose fathers are HBsAg carriers may also be necessary.

Child, Preschool↗
PubMed1990

Antibody to p40tax protein of human T cell leukemia virus 1 and infectivity.

To investigate the physiologic significance of antibody to human T cell leukemia virus type 1 (HTLV-1) tax gene product (p40tax), 147 male and 243 female HTLV-1 carriers were examined for anti-p40tax, and 104 carriers were checked for anti-p40tax an average of 5.4 times during an 8-year period. Prevalence of anti-p40tax was significantly higher in female (62.6%) than in male subjects (51.0%; P less than .05). Anti-p40tax status did not change in most during the observation period. There were significantly more HTLV-1 carriers among children of anti-p40tax-positive mothers (45.3%) than among those from anti-p40tax-negative mothers (20.0%; P less than .01). However, no significant difference was observed between wives of p40tax-positive and -negative men. The p40tax antibody may be a marker of relative infectivity of HTLV-1, albeit an imperfect one.

Adolescent↗
PubMed1990

Chronic central GABAergic stimulation attenuates hypothalamic hyperactivity and development of spontaneous hypertension in rats.

To determine whether chronic central gamma-aminobutyric acid (GABA) stimulation would attenuate development of hypertension, tail-cuff systolic pressures were measured in male spontaneously hypertensive rats (SHR) treated with either an inhibitor of GABA breakdown (valproate, VPA), or a GABA-receptor agonist (muscimol). When VPA was injected intraperitoneally (i.p.) daily for 4 weeks, tail-cuff systolic pressures were decreased during the last 2 weeks. On the other hand, continuous infusion of muscimol into the lateral cerebral ventricle for 14 days using an osmotic minipump decreased systolic pressures throughout the 10-day observation period. During terminal experiments under urethane anesthesia, pressor and sympathetic nerve responses to electrical stimulation of the ventromedial hypothalamus were reduced in VPA- or muscimol-treated SHR. Pressor responses to intravenously (i.v.) injected norepinephrine (NE) were unaltered by either treatment, indicating that diminished pressor responsiveness to hypothalamic stimulation was not due to diminished cardiovascular reactivity. Regardless of either VPA acid or muscimol treatment, basal blood pressure (BP), heart rate (HR), and responses to hypothalamic stimulation were lower in normotensive Wistar-Kyoto controls (WKY) than in SHR. In addition, chronic treatment with either drug had weaker hypotensive and hypothalamic depressant effects in WKY than in SHR. Our results suggest that in SHR the central GABAergic system is impaired and that chronic treatment with GABAergic stimulants can attenuate development of spontaneous hypertension by reducing hypothalamic overactivity.

Animals↗
PubMed1990

Study of seroconversion of antibody to human T-cell lymphotropic virus type-I in children of Okinawa, Japan.

From 1983 to 1986, 1,813 children in nursery schools in Ishigaki Island and 1,228 children under 15 years old in the rural area in the Yaeyama District of Okinawa, Japan, were tested for anti-HTLV-I; 18 children (1.0%) in Ishigaki Island and 39 children (3.2%) in the rural area were positive. In order to survey when anti-HTLV-I developed in these children, their older serum samples were investigated retrospectively for 1 to 5 years. Two cases of seroconversion from anti-HTLV-I negative to positive were found between the age of 2 and 4, and there were no cases of seroconversion over 4 years old. Among the children who suffered maternal transmission of HTLV-I and developed anti-HTLV-I before the age of 15, about 80% of the children were considered to have anti-HTLV-I before the age of 2, and the remainder developed anti-HTLV-I before the age of 4.

Adolescent↗