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Biomedical subjects

K Shirai

Publications and source records attributed to K Shirai.

At least 163 records · Page 9Linked to original sources
PubMed1989

Detection of impaired fibrinolytic activity in coronary artery disease--electrophoretic and immuno-blotting analysis of tissue plasminogen activator.

In present study, we investigated the fibrinolytic activities and plasma antigen levels of tissue plasminogen activator (tPA) before or after a submaximal exercise in patients with coronary artery disease (CAD). We also investigated tPA phenotypes in plasma by electrophoretic and immuno-blotting analysis. Euglobulin fractions obtained from plasma were submitted to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting analysis. There were no differences in plasma antigen levels of tPA between the study group and controls before or after the exercise, however CAD patients showed lower fibrinolytic activities after the exercise than controls. SDS-PAGE followed by immuno-blotting with an antisera against human tPA revealed two bands at molecular weights (m.w.) of 70,000 and 120,000. The band at m.w. of 70,000 corresponded to free tPA and that of 120,000 was considered to be identical to a complex of tPA with its inhibitor. Furthermore, we found a decrease in free tPA in the patients with low fibrinolytic activities. From these results it was concluded that impaired fibrinolytic activities, probably due to decreased free tPA, observed in CAD patients, might be an important factor in the pathogenesis of CAD.

Adult↗
PubMed1988

Effects of phospholipids on hydrolysis of trioleoylglycerol by human serum carboxylesterase.

Human serum carboxylesterase (EC 3.1.1.1), purified by affinity chromatography on trimethylammonium anilinium-Sepharose, hydrolyzed the short-chain fatty acid ester tributyrin (40 mumol/mg protein per h), but scarcely hydrolyzed the long-chain fatty acid ester triolein (less than 0.2 mumol/mg protein per h). Phospholipids enhanced triolein hydrolysis by carboxylesterase to various extents, cardiolipin causing the most enhancement (2.5 mumol/mg protein per h). Phosphatidylserine and phosphatidylinositol also enhanced carboxylesterase-catalyzed hydrolysis of triolein (450-980 nmol/mg protein per h). The optimal pH for tributyrin hydrolysis was pH 8.0, but the pH range for triolein hydrolysis was broad, being pH 4.5-7.5. The rates of hydrolyses of monoolein, diolein and triolein by carboxylesterase in the absence and presence of 100 micrograms/ml cardiolipin were 3.9, 0.5 and 0.2 mumol/mg esterase per h and 2.0, 0.6 and 4.0 mumol/mg protein per h, respectively. Thus, on addition of cardiolipin, triolein hydrolysis was enhanced, but tributyrin hydrolysis was reciprocally decreased. Triton X-100 (0.1%) and NaCl (1.0 M) decreased triolein hydrolysis, but did not decrease tributyrin hydrolysis. Mercaptoethanol decreased triolein hydrolysis, but not tributyrin hydrolysis. These results suggest that cardiolipin modifies the interaction of carboxylesterase with substrates in such a way as to facilitate its interaction with a hydrophobic substrate, and that disulfide bonding might be involved in the substrate recognition site.

Carboxylesterase↗
PubMed1988

Hydrolysis of low-density lipoprotein phospholipids in arterial smooth muscle cells.

The hydrolysis of phosphatidylcholine (PC) associated with low-density lipoprotein (LDL) by homogenates of smooth muscle cells from rabbit aorta was studied. 1-Palmitoyl-2-[14C]oleoylPC associated with LDL (LDL-P[14C]OPC) or 1-linoleoyl-2-[14C]linoleoylPC associated with LDL (LDL-L[14C]LPC) was used as the substrate. The optimum pH for the formation of [14C]oleoyllysoPC from LDL-P[14C]OPC and for the formation of [14C]linoleoyllysoPC from LDL-L[14C]LPC was pH 4.5, and pH 4.5 and 7.0, respectively. These activities were designated as phospholipase A1 activities. The optimum pH values for the formation of [14C]oleate from LDL-L[14C]OPC and for the formation of [14C]linoleate from LDL-L[14C]LPC were pH 4.5 and 6.5, and pH 4.5, 6.5 and 8.5, respectively. These activities were designated as phospholipase A2 activities. Ca2+ did not affect acid phospholipase A1 activity, but decreased acid phospholipase A2 activity for the hydrolysis of LDL-L[14C]LPC. When smooth muscle cells were incubated with LDL, both phospholipase A1 and phospholipase A2 activities at pH 4.5 for the hydrolysis of LDL-L[14C]LPC increased significantly. These results indicate that phospholipases A1 and A2, which hydrolyze PC associated with LDL, exist in arterial smooth muscle cells and are involved in the metabolism of LDL incorporated into these cells.

Animals↗
PubMed1988

Proliferation and LDL binding of cultured intimal smooth muscle cells from rabbits.

Cultured intimal smooth muscle cells (SMC) were prepared from rabbits in which a cannula had been inserted into the abdominal aorta 4 weeks previously. The patterns of growth proliferative rates, and lipoprotein metabolism of cultures of intimal and medial SMC from intact aortic media were compared. Intimal SMC proliferated more rapidly than medial SMC. Both low density lipoprotein (LDL) and acetylated LDL bound to intimal SMC, whereas only LDL bound to medial SMC. These findings suggest a phenotypic difference between intimal and medial SMC.

Animals↗
PubMed1988

A familial hyperalphalipoproteinemia with low uptake of high density lipoproteins into peripheral lymphocytes.

A patient with an extremely high level of high density lipoprotein (HDL)-cholesterol and HDLc-like particles in the serum is discussed. The patient was a 46-year-old female with a serum total cholesterol concentration of 382 mg/dl and HDL-cholesterol level of 214 mg/dl. The HDL-cholesterol levels of her mother, brother, sister and 2 of her daughters were 82 mg/dl, 82 mg/dl, 74 mg/dl, 82 mg/dl and 82 mg/dl, respectively (mean HDL-cholesterol levels of control subjects: 52 +/- 6 mg/dl in males and 55 +/- 8 mg/dl in females). Her serum apolipoprotein A-I and E levels were elevated. Zonal ultracentrifugal analysis of her serum lipoproteins showed that the increased level of HDL-cholesterol was mainly due to HDL2; HDLc-like particles were also recognized between the LDL and HDL fractions. The incorporation of the patient's HDL and HDLc-like particles into cultured HepG2 cells was almost the same as that of HDL (1.063 less than d less than 1.21) from normal control serum. The incorporation of normal control HDL into the patient's peripheral blood lymphocytes was markedly less than that into lymphocytes from normal controls. These findings are discussed in terms of the reason for hyperalphalipoproteinemia in this patient.

Animals↗
PubMed1988

Effect of a new synthetic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor on cholesterol synthesis and low density lipoprotein uptake by primary cultures of rat hepatocytes.

CS-514 ((+)-sodium (3R,5R)-3,5-dihydroxy-7-[(1S,2S,6S,8S,8aR)-6-hydroxy-2- methyl-8-[(S)-2-methyl-butyryl]-1,2,6,7,8-hexahydro-1-naphthyl] heptanoate) which was recently synthesized as an inhibitor of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase lowers serum cholesterol levels. This compound inhibited cholesterol synthesis dose-dependently from acetate in primary cultures of rat hepatocytes. At high concentration (0.5 and 5.0 mumol/l), but not at lower concentration, it inhibited bile formation from acetate. Low density lipoprotein (LDL)-[3H]-cholesteryl linoleate incorporation into hepatocytes was increased when the cells were preincubated with 0.5 or 5.0 mumol/l CS-514 for 12 h. Bile formation from LDL-[3H]-cholesterol linoleate was not affected by addition of CS-514. These results suggest that inhibition of de novo cholesterol synthesis by CS-514 enhanced LDL receptor function in primary cultures of rat hepatocytes and lowered LDL-cholesterol level.

Acetates↗
PubMed1987

Abnormal metabolism of polyunsaturated fatty acids and phospholipids in diabetic glomeruli.

Studies were done on changes in phospholipid content and fatty acid composition of phospholipids and on the role of the acylation pathway in synthesis of phospholipids in the development of abnormal fatty acid composition in the glomeruli of rats 2 and 10 mo after induction of diabetes with streptozotocin. The proportions of individual phospholipids in the glomeruli of rats were not changed 2 mo after induction of diabetes, but the proportion of phosphatidylethanolamine (PE) decreased and that of sphingomyelin increased 10 mo after induction of diabetes. In contrast, in liver the proportion of PE was increased and that of phosphatidylcholine was decreased. These results showed that changes of individual phospholipids in glomeruli were time-dependent and tissue-specific. Two mo after induction of diabetes, the main change in the phospholipid fatty acid composition of diabetic glomeruli was a decrease in arachidonic acid (AA); the main change in serum free fatty acids (FFA) was an increase in linoleic acid (LA) and a decrease in AA. Ten mo after induction of diabetes, the main changes in the phospholipid fatty acid composition of glomeruli were an increase in LA and a decrease in AA; the main change of the serum FFA composition was a decrease in AA. Thus, the fatty acid composition of glomerular phospholipids was not directly correlated to that of the serum in diabetic rats. Acyl-CoA synthetase and acyltransferase activities increased in diabetic glomeruli with either AA or LA as substrate, but activity toward LA increased more at 2 mo after induction of diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Benign prostatic epithelial polyp of urethra.

A case report of polypoid tumor of the prostatic urethra is presented. The tumor was resected transurethrally, and histologic examination revealed a papillary tumor containing prostatic glandular structure.

Adult↗
PubMed1987

Anesthetic management in the arterial switch "jatene" operation for transposition of the great arteries.

The arterial switch "Jatene" operation for transposition of the great arteries (TGA) is an anatomic reconstruction at the level of the great arteries with reimplantation of the coronary arteries. The anesthetic management of 46 patients who underwent the Jatene operation between 1982 and 1985 was retrospectively reviewed. The mean age was 12.3 +/- 11.2 months (youngest: 4 days) and the mean body weight was 7.0 +/- 2.8 kg (smallest: 3.0 kg). Anesthesia was induced with ketamine in 35 patients, and maintained with morphine in 36 patients. Catecholamine (CA) drugs were given to 10 patients before cardiopulmonary bypass (CPB) and to all patients after CPB. In addition, nitroglycerin (NTG) was given to 13 patients during and after CPB. Platelets were given to prevent bleeding due to platelet damage caused by CPB. Six patients died, producing a mortality rate of 13%. Body weight, age, anesthetic agent, dose of CA, volume of blood loss, and duration of aortic cross-clamping, anesthesia, and operation were not significantly related to the deaths. Urinary output was significantly smaller (P < .05) in the patients who died. The LV/RV pressure ratio was as low as 0.625 and 0.645 in two of six deaths due to left ventricular hypoplasia. Severe pulmonary hypertension occurred in the postoperative period in two patients, and two patients had heart failure following a previous operation for coarctation or interruption of the aorta. Since hypotension during induction is detrimental in these cases, ketamine was commonly used as an induction agent. Morphine was chosen rather than fentanyl to avoid bradycardia. Administration of CA drugs produced an inotropic effect on the heart, and NTG helped maintain coronary blood flow and prevented pulmonary hypertension. There were no anesthetic deaths as judged by both the surgeons and anesthesiologists.

Adjuvants, Anesthesia↗
PubMed1987

Modification of intracellular glucose metabolism in human skin fibroblast preincubated with p-chlorophenoxyisobutyrate.

1. The effect of p-chlorophenoxyisobutyrate (CPIB) on glucose metabolism human skin fibroblasts was examined. 2. CPIB increased the incorporation of 2-deoxy-D-[U-14C]glucose into skin fibroblasts. 3. CPIB decreased [14C]CO2 production from D-[U-14C]glucose but did not affect pyruvate dehydrogenase activity. 4. CPIB reduced fatty acid oxidation activity and cholesterol synthesis but increased triglyceride synthesis. 5. These effects of CPIB were observed both in the presence and in the absence of insulin. 6. One possible mechanism of CPIB on reducing plasma glucose may be due to the increase of glucose incorporation into the cells and triglyceride synthesis in the cells.

2-Methyl-4-chlorophenoxyacetic Acid↗