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Biomedical subjects

S Yanagi

Publications and source records attributed to S Yanagi.

At least 73 records · Page 4Linked to original sources
PubMed1994

Comparative effects of milk, yogurt, butter, and margarine on mammary tumorigenesis induced by 7,12-dimethylbenz(a)anthracene in rats.

The effects of margarine and butter on mammary tumorigenesis were compared in the first experiment. Altering the levels of dietary margarine and butter influenced the development of mammary tumors induced with 7,12-dimethylbenz(a)anthracene (DMBA) in rats. Margarine enhanced tumorigenesis dose dependently in both the incidence and the number of mammary tumors. On the other hand, butter that was substituted for margarine did not show any enhancing effects. Inasmuch as butter is made from cow's milk, the effect of cow's milk was studied in the second experiment. It was expected that milk might inhibit mammary tumorigenesis. Contrary to our expectations, however, milk and yogurt did not inhibit but enhanced the DMBA-induced mammary tumorigenesis. It remains to be elucidated whether the enhancing effect was caused by some specific factors in milk or by the difference in energy or nutrient intakes.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1993

Protein-tyrosine kinase p72syk is activated by thrombin and is negatively regulated through Ca2+ mobilization in platelets.

Activation of platelets by thrombin results in a dramatic increase in tyrosine phosphorylation on multiple cellular proteins (Ferrell, J. E., and Martin, G. S. (1988) Mol. Cell. Biol. 8, 3603-3610; Golden, A., and Brugge, J. S. (1989) Proc. Natl. Acad. Sci. U. S. A. 86, 901-905; Nakamura, S., and Yamamura, H. (1989) J. Biol. Chem. 264, 7089-7091). However, none of the responsible protein-tyrosine kinase has been reported so far. We report here that p72syk, one of the non-receptor-type protein-tyrosine kinases, is activated following thrombin stimulation in blood platelets. Washed porcine platelets were stimulated by thrombin, and the activation of p72syk was assessed in an immunoprecipitation kinase assay. The activity of p72syk increased within 5 s, reached a maximum at 10 s, and decreased to a basal level within 60 s after 0.5 unit/ml thrombin stimulation. The amount of immunoprecipitated p72syk was not altered throughout the time course. This activation was greatly enhanced in a dose-dependent manner and was completely canceled by the pretreatment of platelet suspension with hirudin, a specific antagonist of thrombin. In the Ca(2+)-depleted condition both extra- and intracellularly, the activation of p72syk was still persistent; in contrast, the deactivation process was completely abrogated even at 120 s after thrombin stimulation. In addition, the replenishment of Ca2+ resulted in a similar deactivation pattern as seen in the Ca(2+)-rich condition. Furthermore, this deactivation was also canceled by the pretreatment of platelets with W7, a calmodulin antagonist, as well as ML9, a myosin-light-chain kinase inhibitor. These results indicate that p72syk can be a responsible enzyme to the protein-tyrosine phosphorylation events following the platelet activation by thrombin and may be negatively regulated by Ca2+ in a calmodulin-dependent manner, inter alia myosin light-chain kinase, in thrombin-stimulated platelets.

Animals↗
PubMed1993

Effects of inotropic stimulation on phosphate compounds in ischaemic canine hearts.

OBJECTIVE: The aim was to evaluate regional coronary blood flow, contractile function, and concentration of phosphate compounds with inotropic stimulation in moderately ischaemic canine hearts. METHODS: Dogs were prepared with instrumentation for the determination of regional coronary blood flow (non-radioactive microsphere method), contractile function (sonomicrometry), and haemodynamics. Myocardial phosphate compounds were measured simultaneously by the phosphorus-31 magnetic resonance spectroscopic technique. RESULTS: In the non-ischaemic condition, dobutamine increased regional coronary blood flow and enhanced contractile function with no significant changes in myocardial phosphate compounds. After constricting the left anterior descending coronary artery, dogs were divided into two groups according to their heart beat response to dobutamine, classified as no pronounced tachycardia with dobutamine (group NT), and pronounced tachycardia (group T). In group NT, dobutamine increased regional coronary blood flow and improved regional contractile function with no significant effect on myocardial phosphate compounds. In group T, dobutamine failed to increase regional coronary blood flow or to improve contractile function, but there was a significant increase in the inorganic phosphate to creatinine phosphate ratio. CONCLUSIONS: Dobutamine increased coronary blood flow and augmented contractile function without significant changes in phosphate compounds in the moderately ischaemic heart, when pronounced tachycardia was not induced. The augmentation of contractile function occurred without prominent improvement in energy metabolism.

Animals↗
PubMed1993

Results obtained from microsurgical therapy of varicocele.

The microsurgical method of varicocelectomy was performed in 56 patients. In 25 cases the procedure was done because of scrotal symptoms and in 31 cases as a treatment for infertility. Complete regression of varicosities was observed in all the cases including 2 recurrent ones. The conception rate was 56% in the infertility patients excluding azoospermic and severe oligozoospermic ones. This microsurgical method has a good success rate and is also quite satisfactory in terms of its pregnancy rate.

Adult↗
PubMed1993

Estimation of infarct size using serum troponin T concentration in patients with acute myocardial infarction.

To estimate the size of myocardial infarction, serum troponin T concentration was measured in 34 patients with acute myocardial infarction. Left ventriculography, 2-dimensional echocardiography and resting 201thallium myocardial single photon emission computed tomography (SPECT) were performed about 4 weeks after the onset of myocardial infarction and used for correlation with the late serum troponin T peak concentration which occurred on the 3rd to 5th day after onset. Both left ventricular ejection fraction (LVEF) obtained from left ventriculography and wall motion index (WMI) obtained from 2-dimensional echocardiography were inversely related to late troponin T peak value (LVEF: r = 0.68, p < 0.001, WMI: r = 0.70, p < 0.001). Extent score (ES) and severity score (SS), which were estimated from the initial resting 201thallium SPECT image, showed excellent linear correlations with late troponin T peak concentrations (ES: r = 0.77, p < 0.001, SS: r = 0.66, p < 0.001). This correlation was present both in patients with an early troponin T peak on day 1 (group A-16 patients) and in those without an early peak (group B-10 patients). Thus, late troponin T peak concentration can be used to predict infarct size regardless of the kinetics of its appearance in serum.

Adult↗
PubMed1993

[Evaluation of vasculogenic erectile impotence using DICC (dynamic infusion cavernosometry & cevernosography) with intracavernous injection of papaverine].

Dynamic infusion cavernosometry and cavernosography (DICC) with intracevernous injection of papaverine was performed in 28 men. The change of the corporal body pressure after injection of papaverine and the intracavernous pressure decrease within the first 30 seconds after discontinuation of saline infusion were observed. Four different patterns of cavernometric findings can be identified on the basis of the intracavernous pressure behavior in response to injection of papaverine, infusion of saline and discontinuation of infusion: pattern A represents no vasculogenic insufficiency, pattern B represents pure arterial insufficiency, pattern C clearly represents venous leak and pattern D represents venous leak and arterial insufficiency. Cavernosography has found out effectively the sites of venous leakage in most our cases.

Adult↗
PubMed1993

[Ileal low pressure bladder substitute with a tubular afferent limb: report of two cases].

We anastomosed the ileal reservoir to the membranous urethra in 2 male bladder cancer patients accepted for total cystectomy. Construction of the reservoir was performed according to Studer et al. (Br J Urol 63: 43-52, 1989). The procedure entails the use of 60 cm of ileal segment. The proximal segment, 15 cm, was left tubular to act as the inflow urinary tract. Anastomosis of the ureters to a tubular afferent ileal limb was carried out by end to side without anti-reflux method. The renal function was not changed by the operation. More than one year after the operation, urodynamic evaluation showed the reservoir to be low pressure with a capacity that increased to more than 400 ml. In both cases, however, about 300 ml residual urine was observed. Now both patients are performing intermittent self-catheterization and are continent night and day. When considering quality of life, this procedure is suitable whenever the urethra can be preserved after total cystectomy. For making a more "natural" bladder substitute, however, some modification of the operative procedure including anti-reflux system may be required.

Aged↗
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↗