Biomedical subjects

M Ohashi

Publications and source records attributed to M Ohashi.

At least 235 records · Page 13Linked to original sources

PubMed1992

Thermal coefficients of paste-paste type pulp capping cements.

Thermal coefficients of four kinds of commercially available paste-paste type pulp capping cements were examined. Control reference samples were made of dentin. A thermal coefficient analyzer was used, heating specimens for a few nanoseconds by a xenon flash bulb and measuring thermal changes by using a thermocouple. Thermal coefficients were examined by this non-steady state method. Thermal conductivities of all cements were almost the same or lower than that of dentin. Therefore, when each cement was heated, the penetrating energy was almost the same or lower than that of dentin. The thickness of the cements was converted into that of the dentin by using the obtained thermal conductivity. The 1-mm thickness of the examined cements were equal to between 0.97-mm and 2.10-mm thicknesses of lost dentin. The use of a pulp capping cement provided better pulp protection from thermal stimuli than did the same thickness of dentin.

Calcium Hydroxide↗

PubMed1992

Significance of tubuloreticular structures in infants with neonatal lupus erythematosus and their mothers with Sjögren's syndrome.

Four infants with neonatal lupus erythematosus who had annular erythema on the trunk and face reacted positively to tests for anti-Ro(SS-A)/La(SS-B) antibodies. Electron microscopic examination of vascular endothelial cells in the annular erythema revealed the presence of tubuloreticular structures. Once anti-Ro(SS-A)/La(SS-B) antibodies had turned negative, these tubuloreticular structures were no longer evident in the vascular endothelial cells in the same area where annular erythema had been present. Mothers of these 4 infants reacted positively to anti-Ro(SS-A)/La(SS-B) antibodies, but had no sicca syndrome. A biopsy taken from the minor salivary gland of the lip of each mother revealed marked periductal mononuclear cell infiltration. Primary subclinical Sjögren's syndrome was confirmed. Tubuloreticular structures were also observed in the vascular endothelial cells in the region of the minor salivary gland. These findings suggest that the presence of tubuloreticular structures may be related to anti-Ro(SS-A)/La (SS-B) antibodies.

Adult↗

PubMed1992

Utility of the latex agglutination nephelometric immunoassay (Albusure Test) in screening for microalbuminuria in patients with diabetes mellitus.

All diabetic patients should be screened for early signs of diabetic nephropathy, because it is a prognostic factor in the disease. The albusure test (AT), a latex agglutination nephelometric immunoassay, is a rapid and low cost test for the detection of microalbuminuria of 30 mg/L or more. We compared the results of AT and of radioimmunoassay (RIA) for urinary albumin to evaluate the clinical utility of AT using fresh urine samples from 74 diabetic patients without persistent proteinuria and from 11 healthy subjects. Urinary albumin levels were 6.0 +/- 2.3 mg/L in the healthy subjects, 11.0 +/- 8.7 mg/L in the AT-negative group (n = 61), and 38.1 +/- 10.2 mg/L in the AT-positive group (n = 13). Using a cut-off value of 30 mg/L by RIA, the rate of coincidence between AT and RIA was 89.2%, although five subjects were false-positive by AT, and three were false-negative. These results show that AT may provide a useful monitor for microalbuminuria, a reliable early marker of diabetic nephropathy.

Adult↗

PubMed1992

Clinical characteristics of chronic cutaneous graft-versus-host disease in Japanese leukemia patients after bone marrow transplantation: low incidence and mild manifestations of skin lesions.

We investigated the incidence of chronic graft-versus-host disease (GVHD) and skin and oral lesions in chronic GVHD in 90 Japanese leukemia patients surviving over 100 days after bone marrow transplantation (BMT) from HLA-compatible siblings. The clinical characteristics of chronic cutaneous GVHD occurring in eight of these patients are summarized. There were some differences from previous reports in the USA and Europe. The incidence (8/29: 28%) of skin lesions in chronic GVHD was low in contrast to the previously reported high incidence (79-90%). Cutaneous manifestations in six out of eight patients with chronic GVHD tended to be mild, and lichen-planus-like eruptions in the skin and scleroderma-like lesions, which are well known as representative cutaneous manifestations of chronic GVHD, were rare. Furthermore, our statistical analysis indicated that there was no relationship between pretransplant total body irradiation and GVHD prophylaxis or acute GVHD and the onset of chronic cutaneous GVHD. The present study suggests that the differences from previous reports in the USA and Europe concerning chronic cutaneous GVHD may be attributable to differing genetic backgrounds in Japanese and western populations.

Acute Disease↗

PubMed1992

A novel fluorescence method to monitor the lysosomal disintegration of low density lipoprotein.

A novel fluorescence method to monitor the lysosomal disintegration of low density lipoprotein (LDL) particles in living cells has been developed. The method is based on the fluorescence resonance energy transfer (RET) between two fluorescent molecules incorporated into LDL particles. NBD-cholesterol linoleate (NBD-CL) and octadecyl rhodamine B (R18) were incorporated simultaneously into LDL, as a RET donor and a RET acceptor, respectively. In this preparation of LDL (RET-LDL), efficient RET was observed, and after the disruption of the LDL particle by a Triton X-100 treatment, the relief of the RET was observed. RET-LDL was endocytosed by CHO cells via LDL receptors, and the RET-LDL particles were disintegrated after the uptake. The resultant relief of the RET upon the disintegration of the LDL was monitored by flow cytometry, and the amount of intact LDL in cells was estimated by calculation. The disintegration occurred with an about 25 min lag, and was inhibited by several lysosomal inhibitors. These results indicate that the disintegration was not a nonspecific event, but took place at the level of lysosomes. Since living cells can be analyzed by the present method, when coupled to flow sorting, it would permit the isolation of cells having different properties in the endocytic pathway of LDL.

Animals↗

PubMed1992

[A trial of low-dose aspirin therapy in high-risk pregnancy].

Intra-uterine growth retardation, intra-uterine fetal death and pre-eclampsia have common abnormalities: A reduction of uteroplacental perfusion, lack of vasodilation of spiral arteries and subsequent thrombosis. These physiological processes have been explained by an imbalance between prostacyclin and thromboxane A2 production. Many studies have suggested that treatment with low-dose aspirin and steroids is effective in preventing pregnancy loss or pre-eclampsia, but the mechanism has not been established. We evaluated the effectiveness of these therapies in patients at risk for pregnancy loss with the aspect of intracellular ionized calcium mobilization. Low-dose aspirin directs the prostacyclin/thromboxane A2 balance to the dominance of prostacyclin and steroids suppress the activities of lupus anticoagulant or antiphospholipid antibodies. The intracellular ionized calcium concentration in platelets is decreased significantly after these therapies. Concerning the pathological examination of placenta, there were deposits of fibrin in only 2 out of 8 cases and there were no abnormal findings in the other 6 cases. These data show that the aggregation of platelets is suppressed in microvascular circulations. These therapies do not cause any adverse effect on the mother or fetus. It is concluded that low-dose aspirin therapy with steroids is useful for patients with a poor obstetrical history.

6-Ketoprostaglandin F1 alpha↗

PubMed1992

[A case of hyporeninemic hypoaldosteronism improved by dexamethasone treatment].

A 76-year-old man was admitted because of general fatigue and lumbago. Two years before admission, hyponatremia and hyperkalemia were pointed out, subsequently hydrocortisone (20 mg/day) was given under the diagnosis of panhypopituitarism. The marked improvement was found in the electrolytes abnormality. On examination at admission, there was no abnormality of anterior pituitary function. In addition to the extremely low level of plasma renin activity and aldosterone concentration, the persistent microhematuria and hyperuricemia were found, however, renal histology only showed the benign arteriosclerosis but no significant alteration in juxtaglomerular apparatus and glomeruli. The urinary prostacyclin metabolite output was rather increased compared to that of normal subject, suggesting that prostaglandins may not be responsible for the defect of renin secretion. Although, the cause was still unknown, small dose of dexamethasone was extremely effective to resolve electrolytes abnormality and hematuria.

Aged↗

PubMed1991

Presence of non-selective type of endothelin receptor on vascular endothelium and its linkage to vasodilation.

We studied the role of non-selective type (ETB) of endothelin (ET) receptor in the vasculature, using a ligand specific to the ETB receptor, [Glu9]-sarafotoxin S6b ([Glu9]SRTb). Endothelium-containing rat thoracic aorta possessed specific binding sites for 125I-[Glu9]SRTb, which were almost eliminated by removal of the endothelium, while ET-3-specific binding sites were not detected in the endothelium-intact rat aorta. Only ETB receptor was detected in the membranes from the endothelium of porcine thoracic aorta. [Glu9]SRTb exerted only vasodilation in rat aortic ring. These findings indicate that ETB receptors are located on vascular endothelium and linked to vasodilation.

Animals↗

PubMed1991

Binding characteristics of a new 1,5-benzothiazepine, clentiazem, to rat cerebral cortex and skeletal muscle membranes.

The binding properties of a new 1,5-benzothiazepine, clentiazem (TA-3090), were investigated in rat cerebral cortex and skeletal muscle membranes with [3H]diltiazem and [3H]nitrendipine as radioligands. Clentiazem inhibited [3H]diltiazem binding to cerebral cortex membranes at the same concentrations as diltiazem at 2 degrees C. However, at 37 degrees C clentiazem was 3 times more potent to inhibit binding than diltiazem. [3H]Nitrendipine binding was modulated by clentiazem in a temperature-dependent manner. At 37 degrees C clentiazem significantly enhanced [3H]nitrendipine binding to rat cerebral cortex membranes, whereas it has an inhibitory effect on [3H]nitrendipine binding at 0 degree C and no effect at 25 degrees C. Of two optical isomers of clentiazem and four of diltiazem, only d-cis isomers (clentiazem and diltiazem) increased [3H]nitrendipine binding, indicating that both compounds have the same stereoselectivity for increasing [3H]nitrendipine binding. These results suggest that clentiazem binds to the same 1,5-benzothiazepine binding sites as diltiazem but with greater affinity.

Animals↗

PubMed1991

Multiple subtypes of endothelin receptors in porcine tissues: characterization by ligand binding, affinity labeling and regional distribution.

To clarify the existence and the distribution of endothelin (ET) receptor subtypes, we have examined the pharmacological properties and the molecular weight (Mr) of 125I-ET-1 and 125I-ET-3 binding sites in various tissues of pigs. ET-1 and ET-2 showed almost identical potencies in displacing the bound 125I-ET-1 in all the tissues examined. ET-3, sarafotoxin S6b (SRT-b) and sarafotoxin S6c (SRT-c) displaced the 125I-ET-1 with the same sensitivity as ET-1 (IC50 = 0.1-1.4 nM) in brain, kidney, liver and adrenal, whereas the three peptides showed very weak competition (IC50 = 40-500 nM) against 125I-ET-1 binding in cardiac atria, aorta, lung, stomach and uterus. The computer analyses of the binding data suggested the presence of high (Kd1 = 0.04-0.29 nM) and low (Kd2 = 60-190 nM) affinity binding sites for ET-3 and SRT-b in lung and stomach. 125I-ET-3 bound to the high affinity sites in lung and stomach was displaced by ET/SRT isopeptides almost equipotently. Two proteins with Mr of 47,000 and 35,000 were affinity-labeled with 125I-ET-1 in cerebellum, while a protein with Mr of 123,000, in addition to the two proteins, was predominantly labeled in lung. The above findings indicated that two distinct subclasses of ET receptors, namely, ET-1-specific and ET/SRT family-common receptors were distributed in various proportions in mammalian tissues, and suggested that their molecular forms are also different.

Affinity Labels↗

PubMed1991

Rupture of the ascending aorta after surgical resection for lung cancer--a case report.

A rupture of the ascending aorta which occurred in a woman on the 13th postoperative day following a right upper lobectomy with mediastinal lymph node dissection for lung cancer is reported herein. Fortunately, the patient was rescued from a cardiac tamponade and hemothorax by emergency operation. The operative findings suggested a traumatic rupture of the aorta, however, lymph node dissection of the mediastinum could not be excluded as a possible cause. Therefore, careful mediastinal lymph node dissection should be carefully performed in operations for lung cancer.

Aged↗

PubMed1991

An inhibitory effect of a protein kinase inhibitor, staurosporine, on delivery of endocytosed asialoglycoprotein to lysosome in monolayer culture of rat hepatocytes.

An inhibitor of protein kinases, staurosporine (ssp), was found to affect the endocytic pathway of asialoglycoproteins subsequent to endocytosis in monolayer cultures of rat hepatocytes. The effect of 5 or 10 microM staurosporine on the internalization of a synthetic ligand (galBSA-HRP: bovine serum albumin exposing galactose, horseradish peroxidase conjugates) prebound to the cell surface was minimal. The presence of 5, 7, or 10 microM ssp during a 1-h chase period resulted in the ligand remaining in a low density (1.04-1.05 g/ml), nonlysosomal subcellular fraction in a Percoll gradient. The ligand, arrested by 7 microM ssp, was further processed to the lysosome during subsequent incubation in the absence of ssp. Cells maintained the ability to internalize ligand at 37 degrees C for 1 h in the presence of these concentrations of ssp. During a 1-h continuous uptake of 0-50 micrograms/ml nonlabeled ligand, the presence of 7 microM ssp did not cause any decrease in the amount of asialoglycoprotein receptor at the cell surface, which indicates receptor recycling occurred normally. These results suggest a possible involvement of protein kinase(s), which can be inhibited by ssp, in the delivery of endocytosed ligand to the lysosome, but not in ligand endocytosis and receptor recycling.

Alkaloids↗

PubMed1991

Markedly increased expression of cytochrome P-450 17 alpha-hydroxylase (P-450c17) mRNA in adrenocortical adenomas from patients with Cushing's syndrome.

We studied the contents of cortisol (F) and dehydroepiandrosterone (DHEA) and the expression of mRNA of cytochrome P-450 for side-chain cleavage (P-450scc), 17 alpha-hydroxylase (P-450c17), 21 alpha-hydroxylase (P-450c21) and 11 beta-hydroxylase (P-450c11) in adrenocortical adenomas from three patients with Cushing's syndrome. The F content was significantly higher in adrenocortical adenomas than in normal adrenal glands, while the DHEA level was similar to that in normal adrenal glands. The adrenal adenomas showed a markedly higher level of P-450c17 mRNA, and a slightly but not significantly increased level of P-450c21 mRNA, compared with normal adrenal glands. The expression of P-450scc and P-450c11 mRNA in the adenomas was similar to that in normal adrenal glands. These results suggest that the overproduction of cortisol in adrenocortical adenomas associated with Cushing's syndrome results from an increased expression of P-450c17 and P-450c21 mRNA.

Adenoma↗

PubMed1991

Expression of cytochrome P-450 mRNAs in steroidogenesis of adrenocortical adenomas from patients with primary aldosteronism.

We studied the contents of aldosterone and cortisol (F) and the expression of mRNA of cytochrome P-450 for side-chain cleavage (P-450scc), 17 alpha-hydroxylase (P-450c17), 21-hydroxylase (P-450c21) and 11 beta-hydroxylase (P-450c11) in adrenocortical adenomas from three patients with primary aldosteronism. The aldosterone content was significantly higher in adrenocortical adenomas than in normal adrenal glands, while F content in adenomas was similar to the level in normal adrenal glands. The aldosterone-producing adenomas showed a markedly higher level of P-450c11 mRNA, a slightly but not significantly increased level of P-450c21 mRNA and a significantly decreased level of P-450c17 mRNA, compared with those in normal adrenal glands. The expression of P-450scc mRNA in adenomas was similar to the level in normal adrenal glands. These results suggested that the renin-independent overproduction of aldosterone in adrenocortical adenomas from the patients with primary aldosteronism results from increasing expression of the mRNA for P-450c11 and decreasing expression of the mRNA for P-450c17.

Adenoma↗

PubMed1991

Atrial and brain natriuretic peptide in adrenal steroidogenesis.

We elucidated the role of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in human and bovine adrenocortical steroidogenesis. The urinary volume, sodium excretion and cyclic GMP (cGMP) excretion and plasma cGMP were markedly increased by the synthetic alpha-human ANP (alpha-hANP) infusion in healthy volunteers. Plasma arginine vasopressin (AVP) and aldosterone levels were significantly suppressed. Both ANP and BNP inhibited aldosterone, 19-OH-androstenedione, cortisol and DHEA secretion dose-dependently and increased the accumulation of intracellular cGMP in cultured human and bovine adrenal cells. alpha-hANP significantly suppressed P450scc-mRNA in cultured bovine adrenal cells stimulated by ACTH. Autoradiography and affinity labeling of [125I]hANP, and Scatchard plot demonstrated a specific ANP receptor in bovine and human adrenal glands. Purified ANP receptor from bovine adrenal glands identified two distinct types of ANP receptors, one is biologically active, the other is silent. A specific BNP receptor was also identified on the human and bovine adrenocortical cell membranes. The binding sites were displaced by unlabelled ANP as well as BNP. BNP showed an effect possibly via a receptor which may be shared with ANP. The mean basal plasma alpha-hANP level was 25 +/- 5 pg/ml in young men. We confirmed the presence of ANP and BNP in bovine and porcine adrenal medulla. Plasma or medullary ANP or BNP may directly modulate the adrenocortical steroidogenesis. We demonstrated that the lack of inhibitory effect of alpha-hANP on cultured aldosterone-producing adenoma (APA) cells was due to the decrease of ANP-specific receptor, which caused the loss of suppression of aldosterone and an increase in intracellular cGMP.

Adrenal Cortex↗

PubMed1991

Isolation and characterization of a monosialosylgangliopentaosyl ceramide from Xenopus laevis oocyte.

A monosialosylgangliopentaosyl ceramide was isolated from Xenopus laevis oocytes. It represented 5.8% of the total acidic glycosphingolipids. From the results of sugar-composition analysis, enzymatic hydrolysis, permethylation analysis, and negative ion fast atom bombardment mass spectrometry, the structure of the ganglioside was determined to be as follows: [sequence: see text] The predominant species of fatty acids were alpha-hydroxy fatty acids, h22:0, h24:0, and h24:1. The long chain bases of this ganglioside consisted mainly of d18:1 sphingosine and phytosphingosine. Other acidic glycolipids were also characterized. The most abundant component of acidic glycolipids was sulfatide, which represented 85.7% of the total acidic glycolipid mixture. GM3, GM2, GM1a, and GD1a were also detected.

Animals↗

PubMed1991

Pure apocrine nevus. A study of light-microscopic and immunohistochemical features of a rare tumor.

The pure apocrine nevus is a rare tumor. A new case of pure apocrine nevi of the bilateral axillary regions in a 48-year-old man is herein reported. The patient had two soft masses of both axillae. The time of onset of the masses was unknown. They were not accompanied by problems of sweating. Histologically, these lesions comprised numerous apocrine glands extending from the reticular layer of the dermis to the subcutaneous tissue. In addition, sections from both of the lesions were stained by immunoperoxidase techniques for the presence of epithelial membrane antigen, carcinoembryonic antigen, and the alpha and beta subunits of S100 protein. Immunohistochemical features of the tumor stained by these antibodies are consistent with a pure proliferation of mature, well-differentiated apocrine glands. The tumor of the present case seems to have developed spontaneously. It is believed, therefore, that the tumor seen in this patient is best categorized as a pure apocrine nevus.

Antigens, Neoplasm↗

PubMed1991

Conversion of big endothelin isopeptides to mature endothelin isopeptides by cultured bovine endothelial cells.

Both the soluble and membrane fractions prepared from cultured bovine endothelial cells (ECs) possessed the converting activities to metabolize big endothelin-1 (big ET-1) to endothelin-1 (ET-1) at neutral pH. Metal chelators inhibited the activities of both fractions, whereas phosphoramidon, a metalloprotease inhibitor, strongly inhibited only the activity of the membrane fraction. Phosphoramidon reduced the secretion of ET-1 and concomitantly enhanced the release of big ET-1 from cultured ECs. The incubations of big ET-1, big ET-2, and big ET-3 with cultured ECs resulted in their conversions to mature ETs. Phosphoramidon also abolished these conversions. These results indicate that vascular endothelium can convert not only endogenous big ET-1 but also exogenous big ET isopeptides to their mature ETs through a phosphoramidon-sensitive neutral metalloprotease.

Animals↗