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Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 883 records · Page 49Linked to original sources
PubMed1987

Protein kinase C and cAMP-dependent protein kinase induce opposite effects on actin polymerizability.

Protein kinase C phosphorylated muscle and non-muscle monomeric actin more efficiently than filamentous actin in vitro. By sedimentation assay, the ratio of phosphorylated to unphosphorylated actin was much higher in sedimentable actin than in the non-sedimentable form, suggesting that phosphorylated actin was more readily incorporated into F-actin than unphosphorylated actin. In contrast, actin phosphorylated by cAMP-dependent protein kinase was found to have weaker polymerizability than the unphosphorylated form. The phosphopeptide mapping pattern of actin phosphorylated by protein kinase C was different from that of actin phosphorylated by cAMP-dependent protein kinase. Thus, both the protein kinases phosphorylate actin differently and induce opposite effects on actin polymerizability.

Actins↗
PubMed1987

Protection of cynomolgus monkeys against infection by human T-cell leukemia virus type-I by immunization with viral env gene products produced in Escherichia coli.

Protection against human T-cell leukemia virus type-I (HTLV-I) infection in cynomolgus monkeys, achieved by immunizing the animals with env gene products of HTLV-I produced in Escherichia coli, was evaluated. Four monkeys that had been immunized with the env product produced antibody against HTLV-I gp68 and gp46, and their sera were found to cause strong inhibition of syncytium formation of a cat fibroblast cell line induced by HTLV-I. Immunized and non-immunized monkeys were challenged with live MT-2 cells, a high HTLV-I-producer cell line. After challenge, all the control non-immunized monkeys were infected with HTLV-I, as judged by the frequent detection of HTLV-I-antigens in cultures of their peripheral blood mononuclear cells (PBMC), whereas no antigens were recovered from PBMC of immunized monkeys. These results indicate that humoral immunity against HTLV-I-envelope protein elicited by immunization with the polypeptides synthesized in bacteria protected the monkeys against primary infection with HTLV-I.

Animals↗
PubMed1987

Enzyme immunoassay discrimination of a new angiotensin-converting enzyme (ACE) inhibitor, cilazapril, and its active metabolite.

Simple and sensitive enzyme immunoassays (EIAs), discriminating a new angiotensin-converting enzyme (ACE) inhibitor, cilazapril [9(s) - [1(s)-(ethoxycarbonyl)-3-phenylpropylamino]-octahydro-10-oxo-6H- pyridazo[1,2-a] [1,2]diazepine-1(s)carboxylic acid] and its active metabolite [9(s)-[1(s)-carboxy-3-phenylpropylamino]-octahydro-10-oxo-6H- pyridazo[1,2-a][1,2]diazepine-1(s)carboxylic acid] were developed for pharmacokinetic studies of this drug which is used as an antihypertensive agent. These assays can be performed directly on serum or plasma specimens without pretreatment. The EIA for cilazapril (prodrug) allowed the determination of as little as 30 pg/mL, while a 1000-times greater concentration of its active metabolite was required to achieve the same extent of inhibition. The EIA for the active metabolite exhibited a sensitivity and specificity similar to those of the prodrug. Plasma specimens from a human volunteer study and a marmoset subacute toxicity study were assayed by these two newly developed EIAs. The plasma levels of active metabolite determined by the EIA were compared with those assayed by radioenzymatic assay, and a good correlation was observed between them.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1987

Laparoscopic histopathological analysis of "gentle undulation" findings observed in patients with primary biliary cirrhosis.

Laparoscopic findings of the liver in 13 cases with primary biliary cirrhosis (PBC) diagnosed by wedge or needle biopsy were investigated. The characteristic features of laparoscopic appearance--gentle undulation--were observed in 11 out of 13 (85%) patients with PBC. These gentle undulations were irregularly shaped areas from 0.5 to 3 cm in diameter. Those observed in s-PBC were greater in number and more pronounced than those in a-PBC. In the concave areas of these undulations, the number of portal tracts was significantly greater than in the convex areas (p less than 0.005). On the contrary, the number of interlobular bile ducts in the concave area was significantly less than in the convex area (p less than 0.005). Therefore, gentle undulation was relatively specific to PBC, and was caused by scar formation and chronic non-suppurative destructive cholangitis in the portal area.

Adult↗
PubMed1987

Age-related decline in deciduogenic ability of the rat uterus.

To study age-related changes in uterine responsiveness to deciduogenic stimuli, virgin female rats of the T strain were ovariectomized at 4, 8, 10, or 12 mo of age and given daily s.c. injections of 3 mg progesterone for 7 days, commencing on the day after operation, and a single s.c. injection of 0.1 microgram estradiol-17 beta on the third day of the period. Endometrial stimulation was effected by either endometrial traumatization or intraluminal instillation of sesame oil or prostaglandin E2 (PGE2), applied 16 h after the injection of estradiol. Decidual response began to decrease at 8 mo of age and completely disappeared between 8 and 12 mo, regardless of the type of induction stimulus. At 8 mo of age, females formed deciduomata in response to instillation of oil or PGE2, only when they had been cycling regularly at the time of ovariectomy. In 10-mo-old rats, instillation of oil or PGE2 invariably failed to elicit a positive response, regardless of the pattern of estrous cycles at surgery. However, if an ovary was transplanted s.c. 5 or 7 mo after ovariectomy at 4 mo of age, the uteri responded positively to oil instillation at 10 and 12 mo of age, after the ovarian grafts had been removed and steroid treatments had been administered. Moreover, a 2-mo interval between ovariectomy at 8 mo of age and the commencement of the standard treatment schedule restored or maintained the uterus's ability to form deciduomata by 10 mo of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1987

Effect of recombinant interleukin 2 on hepatitis B e antigen positive chronic hepatitis.

Eleven patients with hepatitis B (HB) virus related chronic hepatitis were treated with recombinant interleukin 2 (rIL 2). Two hundred and fifty to 1000 units were given intravenously once daily for seven to 28 days. In five patients serum glutamic pyruvic transaminase activity rose transiently. Six patients showed a decrease in HBV DNA polymerase. One patient lost HBs, e antigens (Ags) and gained anti-HBs, e antibodies, while one lost HBs Ag and another HBe Ag. 2'-5' oligoadenylate synthetase activity in mononuclear cells in the peripheral blood did not change during treatment. The number of CD4 positive (helper/inducer) cells and natural killer cell activity increased after therapy (p less than 0.05, p less than 0.01). These results suggest that rIL 2 acts as an immunomodulatory agent enhancing host immune activity and may be beneficial in patients with chronic HB virus infection.

Adult↗
PubMed1987

Distribution among tissues and intracellular localization of cofilin, a 21kDa actin-binding protein.

Cofilin, a 21kDa actin-binding protein, binds to F-actin in a 1:1 molar ratio of cofilin to actin molecule (Nishida, E., S. Maekawa, and H. Sakai, Biochemistry, 23, 5307-5313, 1984) and is capable of controlling actin polymerization and depolymerization in vitro in a pH-sensitive manner (Yonezawa, N., E. Nishida, and H. Sakai, J. Biol. Chem., 260, 14410-14412, 1985). In this study, immunoblot analysis using monospecific antibodies against cofilin showed that cofilin is ubiquitously distributed in a variety of bovine and rat organs and tissues. Cofilin is also present in various cultured cell lines. Indirect immunofluorescence staining of mouse fibroblastic cells and human epidermoid carcinoma cells indicated that cofilin is distributed nearly uniformly in the cytoplasm and is concentrated in ruffling membranes where F-actin is also concentrated as revealed by staining with rhodamine-phalloin. Stress fiber structures were not strongly stained with the anti-cofilin antibody, although stress fiber staining was sometimes observed near the cell periphery in mouse 3T3 cells. These results suggest that the bulk of cofilin may not be associated with F-actin bundles in vivo.

Actin Depolymerizing Factors↗
PubMed1987

Microvascularization of gingival wound healing using corrosion casts.

The healing process in a wound induced by removal of 6 X 6 mm of gingiva and periosteum from the maxillary attached gingiva of 48 adult mongrel dogs was observed to investigate the potential blood supply for grafts placed on denuded bone. Three-dimensional observations were performed over 12 weeks by scanning electron microscopy (SEM) following the manufacture of corrosion capillary casts by acrylic resin injection. Revascularization in the gingival wound was mainly through formation of new capillaries from those existing below the surrounding epithelium with little new capillary formation from the Volkmann canals. Moreover, the periodontium contributed greatly to the vascularization, which was fastest from the gingival margin. Further, simplification of new capillary loops was also fastest from this direction. Regeneration of the periosteum and periosteal vascular plexus was slow, taking about twice the time of connective tissue and capillaries below the epithelium. The results indicated that blood supply to grafts on denuded bone in the early postgraft period would mainly be provided by capillaries below the epithelium surrounding the recipient bed.

Acrylic Resins↗
PubMed1987

Loss of echoes from the gallbladder wall in diagnosis of fatty infiltration of the liver.

Ultrasonograms taken within 24 h before liver biopsy were evaluated retrospectively for fatty infiltration of the liver in 155 non-ascitic patients with liver diseases. Relatively high amplitude echoes of the liver as compared with the kidney were observed in all of 33 patients whose fatty infiltration of the liver occupied more than 10% of each lobule or pseudolobule irrespective of etiology. Among such patients, loss of echoes from the gallbladder wall was additionally found in 18 of 19 cases uncomplicated by hepatic fibrosis, but only in 3 of 14 cases with this complication. We conclude that fatty infiltration without fibrosis in the liver may be differentiated from that with fibrosis by ultrasonic examination.

Adult↗