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Biomedical subjects

S Yanagi

Publications and source records attributed to S Yanagi.

At least 19 recordsLinked to original sources
PubMed1992

Thrombin-induced human platelet aggregation is inhibited by protein-tyrosine kinase inhibitors, ST638 and genistein.

We have investigated the involvement of protein-tyrosine kinases in thrombin-induced aggregation of human platelets, using ST638 and genistein which are known inhibitors of protein-tyrosine kinase. Preincubation of platelets with 50 microM of ST638 or 25 micrograms/ml of genistein completely blocked the platelet aggregation induced with 0.05 unit/ml of thrombin. The increase of protein-tyrosine phosphorylation bands (135-, 124-, 76-, 64-, and 60-kDa) induced with thrombin was also inhibited by these inhibitors in a dose-dependent manner. These inhibitors also blocked the platelet aggregation and protein-tyrosine phosphorylation induced with thrombin in aspirin-treated platelets. Increase of the intracellular Ca2+ concentration induced by thrombin was also inhibited by higher concentrations of genistein. These results suggest that the protein-tyrosine phosphorylation plays a certain role in platelet activation having some relation to the intracellular Ca2+ concentration.

Amino Acid Sequence↗
PubMed1992

Milk cream does not enhance 2,7-dimethylbenz[a]anthracene-induced mammary tumorigenesis.

We have previously reported that a diet enriched with butter showed an inhibitory effect on the development of mammary tumors in mice and rats. To solve the problem of whether the inhibitory effect of butter was caused by lipids of cow's milk, we have studied the effects of dried milk (WM), skim milk (SM) and milk cream (CR) on mammary tumorigenesis in rats. The lowest incidence of mammary tumors was observed in the CR group, although the difference from other groups was statistically not significant. However, the number of papillary carcinomas in the CR group was significantly lower than the WM group. The result indicates that milk lipids have no enhancing effect on mammary tumorigenesis.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1992

Effects of adenosine on cardiac performance and phosphate compounds in microembolised guinea pig hearts.

OBJECTIVE: The excessive release of adenosine has been reported to cause hyperaemia and to attenuate ischaemic injury in microembolised hearts. The direct effects of exogenous adenosine on cardiac performance were investigated in microembolised guinea pig hearts with the simultaneous measurement of phosphate compounds. METHODS: 21 male guinea pig hearts were perfused according to the Langendorff technique and microembolism was induced by injecting microspheres. Hearts were then treated as follows: group A, adenosine 20 microM and theophylline 60 microM; group B, theophylline 60 microM; group C, saline (control). Cardiac performance was monitored and phosphate compounds were measured by 31P magnetic resonance spectroscopy. RESULTS: Group A showed a significant increase in the left ventricular developed pressure and coronary flow, and a modest restoration of ATP content. Pi/(Pi+Pcr) remained virtually constant. There were no significant changes in left ventricular developed pressure or coronary flow in groups B and C. There was a gradual decrease in tissue ATP content and slight increase in Pi/(Pi+Pcr). CONCLUSIONS: Adenosine improved cardiac performance without adverse effect on energy metabolism in microembolised hearts. Adenosine also restored the ATP stores in microembolised hearts. (Pi = inorganic phosphate; Pcr = phosphocreatine.)

Adenosine↗
PubMed1992

Transurethral treatment of bladder diverticulum.

Transurethral resection of the bladder diverticular neck and fulguration of the diverticular mucosa were performed in 31 diverticula. Cystograms showed that 26 of the 31 diverticula had disappeared completely after 1 month. Follow-up cystograms have shown no recurrence, and no further surgical procedures were required. Therefore, we conclude that resection of the diverticular neck from 4 to 8 o'clock to even the gap between the bladder mucosa and diverticular wall in conjunction with transurethral treatment of the prostate, if required, is a safe, fast and effective method.

Aged↗
PubMed1992

Extensive specifically localized myocardial calcium deposition in a hemodialysis patient.

A 51-year-old female who was hospitalized for evaluation of frequent episodes of hypotension, died unexpectedly. At autopsy, there were many fine, white granular deposits in the myocardium, which were more prominent in the subepicardium of the left ventricle than in the subendocardium. Pathologic calcification is sometimes seen in chronic hemodialysis patients and in some organs the sites of calcium deposition are quite specific. There have been few reports concerning the pattern of calcium deposition in the myocardium and, to our knowledge, the reason for this characteristic distribution is unknown. However it may relate to hydrogen ion concentration in the myocardium.

Calcinosis↗
PubMed1992

[A case of inverted Y ureteral duplication with an ectopic ureterocele].

A 29 year-old male with the complaints of two steps urination and sense of residual urine was admitted. At cystoscopy, a ureterocele was found between the normal left ureteric orifice and the bladder neck. Excretory urography demonstrated a radiolucent area in the bladder and a left lower hydroureter. Retrograde pyelography revealed that the left ureter was divided into two branches. Operative exploration demonstrated that the left ureter was an inverted Y ureteral duplication with an ectopic ureterocele; one opened into the ureterocele and the other into the trigone. We resected the ureterocele wall. Four months later, a voiding cystogram did not show vesicoureteric reflux. Now, he has no symptoms and the results of examination are normal. An inverted Y ureteral duplication is the rarest of all anomalies of the ureter. A review of the literature revealed 36 cases reported previously. Clinical analysis was obtained by reviewing 26 of these cases and adding our own (male 10: female 17, average age: 23 years). Complication included 6 cases of ectopic ureteral opening, 6 with blind-ending branch and 5 with ureterocele. The symptoms of this disease depended on the complicating anomalies. The present case was the 5th one of an inverted Y ureteral duplication with a ureterocele in the world literature.

Adult↗
PubMed1991

Ionophore A23187-induced protein-tyrosine phosphorylation of human platelets: possible synergism between Ca2+ mobilization and protein kinase C activation.

Addition of ionophore A23187 to washed human platelets caused a time- and dose-dependent increase in the phosphotyrosyl content of 135, 124 and 76 kDa proteins. Platelets loaded with intracellular Ca2+ chelator 5,5'-dimethyl-bis-(o-aminophenoxy)-ethane-N, N, N', N'-tetraacetic acid before addition of A23187 exhibited no protein-tyrosine phosphorylation. Replenishment of such platelets with extracellular CaCl2 restored A23187-induced protein-tyrosine phosphorylation. Upon stimulation with A23187, both aspirin and ADP scavengers-treated platelets exhibited protein-tyrosine phosphorylation without phosphoinositide hydrolysis and protein kinase C activation. These data show (a) that A23187 stimulates protein-tyrosine phosphorylation by the elevation of intracellular Ca2+, and (b) that A23187-induced protein-tyrosine phosphorylation is independent of formation of endoperoxides/thromboxane A2, released ADP, phosphoinositide hydrolysis and protein kinase C activation. Furthermore, a synergistic effect of A23187 and protein kinase C activators in stimulating protein-tyrosine phosphorylation is suggested.

Blood Platelets↗
PubMed1991

Circulating immunoreactive endothelin in patients undergoing percutaneous transluminal coronary angioplasty.

Circulating immunoreactive endothelin (ir-ET) in the coronary sinus (CS) and the femoral artery (Ao) was measured in patients who underwent percutaneous transluminal coronary angioplasty (PTCA). Plasma ir-ET level in the CS was significantly increased from 1.6 +/- 0.8 pg/mL to 2.0 +/- 1.0 pg/mL after PTCA (P less than .05). Plasma ir-ET level in the Ao tended to increase after PTCA, but it was not significant. Plasma ir-ET level in the CS was not related to the plasma thromboglobulin level, plasma thrombin-antithrombin complex level, mean blood pressure, or heart rate. These results suggest that the increase of plasma ir-ET level in the CS may be associated with the coronary endothelial injury by PTCA.

Adult↗
PubMed1990

Protein-tyrosine phosphorylation and aggregation of intact human platelets by vanadate with H2O2.

The ability of vanadate with H2O2 to stimulate protein-tyrosine phosphorylation and aggregation in intact human platelets was observed. Upon stimulation by these agents, there was a change in the amount of protein-tyrosine phosphorylation of four bands with molecular masses of 80-, 76-, 53- and 38-kDa proteins. The tyrosine phosphorylation in these four bands increased gradually and reached a maximum level at 2 min and then decreased. Aggregation of platelets was also induced by these agents in a dose dependent manner. The observation that the aggregation was preceded by the increase in tyrosine phosphorylation of these proteins suggests that tyrosine phosphorylation may be involved in an early stage of platelet aggregation.

Blood Platelets↗
PubMed1990

[Role of pulse volume recording in the evaluation of penile blood flow].

Pulse volume recordings were obtained in 53 patients who were hospitalized with urological disorders other than impotence. This method seems to record the total blood volume changes in the penis. Pulse volume recordings also were found to correlate with the value of Penile Brachial pressure Index (PBI). Therefore, it proved to be valuable for estimating penile perfusion. Pulse volume recording is a simple, reliable and adaptable screening method for abnormal penile blood flow. Further investigation is necessary to determine the precision with which the method can detect abnormality of penile blood flow in patients with abnormal venous return.

Adult↗
PubMed1989

Effect of ethanol on hepatocarcinogenesis initiated in rats with 3'-methyl-4-dimethylaminoazobenzene in the absence of liver injuries.

In this study special care was taken to discriminate between the direct effect of ethanol on hepatocarcinogenesis and secondary effects such as choline deficiency or fatty liver. Rats were divided into 2 groups, D and N. Group D was initiated using 3'-Me-DAB, while the control group N was not initiated. Groups N and D were divided into 4 sub-groups. Each subgroup was given, in the drinking water, one of the following ethanol solutions: 0, 5, 10 or 15% for 45 weeks. Liver tumors were induced only in D groups. Evidence obtained indicates that: (a) in the N group, ethanol did not cause any apparent disorders in histology and lipid metabolism, and (b) in the D group no significant differences were observed in the incidence of HCCs and other liver lesions. Ethanol thus does not appear to enhance hepatocarcinogenesis, at least in the absence of liver injury.

Animals↗
PubMed1989

Barium granuloma involving urinary bladder.

The first case of barium granuloma involving urinary bladder is reported. Surgical removal was the treatment of choice. Histological diagnosis was foreign body granuloma with xanthomatous inflammation. The foreign body was identified as barium by analytical electron microscopy.

Aged↗
PubMed1989

[Transurethral treatment of bladder diverticulum].

13 patients with bladder diverticula underwent transurethral diverticulectomy. Follow-up cystograms were obtained six months after surgery. The diverticulum had shrunk in all cases and had totally disappeared in 11 (85%). Transurethral diverticulectomy is a simple, effective, and safe procedure. It takes only a short time and can easily be combined with transurethral operations for obstructions of the lower urinary tract.

Aged↗
PubMed1989

[The significance of serum prostate-specific antigen, gamma-seminoprotein and prostatic acid phosphatase as prostate cancer markers].

Prostate-specific antigen (PA), gamma-seminoprotein (gamma-Sm) and prostatic acid phosphatase (PAP) have been evaluated in patients with prostate cancer, benign prostatic hyperplasia (BPH), chronic prostatitis and acute prostatitis. PA has proved to be diagnostically more sensitive than PAP and gamma-Sm for the detection of prostatic cancer. Although PA may be elevated more frequently than PAP and gamma-Sm in patients with BPH, there are possibilities that these patients with elevated PA and normal PAP and gamma-Sm may have prostatic cancer or precancerous conditions not detectable in our routine diagnostic procedures. We report two cases of prostatic cancer with persistently elevated PA and diagnosed after repeated biopsies. Our data suggest that PA is a sensitive and useful tumor marker for the diagnosis of prostatic cancer. PAP and gamma-Sm in combination with PA may serve as more useful for differential diagnosis and confirmation of prostatic cancer.

Acid Phosphatase↗
PubMed1988

Purification and characterization of cytosolic protein-tyrosine kinase from bovine platelets.

A cytosolic protein-tyrosine kinase has been highly purified from bovine platelets using [Val5]angiotensin II as a substrate. The purification procedure involves sequential column chromatography on phosphocellulose, Sephacryl S-200, poly(L-lysine)-agarose, casein-Sepharose 4B and 2',5'-ADP-Sepharose 4B. Analysis of the most highly purified preparations by SDS/polyacrylamide gel electrophoresis revealed a major silver-stained band of molecular mass 71 kDa. This molecular mass was consistent with results obtained from sucrose density gradient centrifugation, indicating that the enzyme exists as a monomer. The purified kinase, called CPTK 71, efficiently phosphorylated tubulin and p36 (calpactin 1 heavy chain). However, it did not phosphorylate H1 histone. Half-maximal enzyme activity was observed at 2.2 microM ATP, and Mn2+, Co2+ and Mg2+ were effective divalent metal ions for the expression of activity. Insulin, epidermal growth factor, and platelet-derived growth factor had little or no effect on the kinase activity of CPTK 71. CPTK 71 had no immunological cross-reactivity with pp60src. These results suggest that CPTK 71 is a novel type of protein-tyrosine kinases among the enzymes so far reported.

Angiotensin II↗
PubMed1988

Protein phosphorylation and activation of human platelets by sodium fluoride.

The ability of sodium fluoride (NaF) and thrombin to stimulate aggregation and protein phosphorylation in intact human platelets was measured and compared. When platelets were stimulated by NaF, phosphorylation of the 20 KDa protein was transient and after 5-10 min returned to the same level as that of unstimulated cells. On the other hand, 47 KDa protein was slowly phosphorylated without obvious dephosphorylation. The slow activation of the 47 KDa protein phosphorylation correlated well with the time required for the aggregation and secretion. Phosphoamino acid analysis showed that the phosphorylated amino acids of the 47 KDa protein from platelets activated by NaF and thrombin were slightly different. These results suggest that different stimuli may lead to the same protein phosphorylation by different biochemical mechanisms of action.

Amino Acids↗