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Biomedical subjects

Y Muto

Publications and source records attributed to Y Muto.

At least 433 records · Page 24Linked to original sources
PubMed1985

Effect of wall shear stress on intimal thickening of arterially transplanted autogenous veins in dogs.

To determine whether or not changes in wall shear stress play a determinant role in the induction of hyperplasia of intimal tissue of arterially transplanted vein grafts, we developed two models of canine femoral arteries. Wall shear stress was defined by variation of wall shear stress (tau-variation) in the cardiac cycle, with the use of a newly designed computational flow waveform analyzer. In the group I model autogenous vein grafts were implanted under flow conditions of 79.7 +/- 3.2 ml/min of the normally high flow rate with 33.1 +/- 1.9 dynes/cm2 of low tau-variation. In the group II model grafts were implanted under conditions of 2.9 +/- 1.8 ml/min of low flow rate with 178.8 +/- 11.0 dynes/cm2 of normally high value of tau-variation. The intimal thickness of 259 +/- 36 microns 4 weeks after implantation in group I was statistically significant compared with that of 31 +/- 14 microns in group II (p less than 0.005). Our study revealed that change in wall shear stress and not the rate of blood flow is the essential hemodynamic factor related to intimal hyperplasia.

Animals↗
PubMed1985

[Controversy on early carcinoma of the gallbladder based on the results of surgical treatment].

Seventy-two cases of carcinoma of the gallbladder removed surgically were retrospectively studied to evaluate the relationship between stage and prognosis, and to define early carcinoma of the gallbladder. These cases were staged according to general rules for surgical studies on cancer of biliary tract (Japanese Biliary Surgical Society). Stage I patients were 23, composed of 13 of mucosal carcinoma, 7 with involvement of the muscularis and 3 with microinvasion into the subserosa. Stage II and III were 14, and Stage IV 35. All patients with mucosal carcinoma were alive with the exception of the one case who died of other cause. Two cases of the remaining 10 Stage I died of recurrence of carcinoma 1.5 years and 2 years after surgery. Five-year survival rates were 100 percent in cases with mucosal carcinoma, 75 percent in cases with muscular involvement or subserosal microinvasion, 31.6 percent in Stage II and III cases. Stage IV was fatal and most of them died within 6 months after surgery. From our data, it may be rational that the early carcinoma of the gallbladder is defined as the carcinoma of which invasion is limited to the mucosa.

Adult↗
PubMed1984

Interaction of trifluoperazine with Tetrahymena calmodulin. A 19F NMR study.

We have used 19F NMR to study interactions of trifluoperazine (TFP), a potent calmodulin (CaM) antagonist, with Tetrahymena calmodulin (Tet. CaM). Changes in chemical shift and bandwidth of TFP caused by adding Tet. CaM in the presence of excess Ca2+ were much smaller than those by adding porcine CaM. The spectral features of the TFP-Tet. CaM solution in the presence of excess Ca2+ were quite similar to those of the TFP-porcine CaM solution in the absence of Ca2+. The exchange rate of TFP from Tet. CaM was estimated to be nearly 20 s-1. The TFP-Tet. CaM solution in the absence of Ca2+ showed a pronounced pH dependence of the 19F NMR chemical shift, whereas the solution in the presence of excess Ca2+ showed a smaller pH dependence. Thus, it was suggested that TFP is located near a hydrophilic region of the Tet. CaM molecule in the absence of Ca2+, while TFP is located near a hydrophobic region of the Tet. CaM in the presence of excess Ca2+.

Animals↗
PubMed1984

Tubular adenoma with squamous metaplasia of the sigmoid colon: a case report.

A case of tubular adenoma with squamous metaplasia of the sigmoid colon in a 44-year-old female is reported. The tumor was a pedunculated polyp with a size of 1.2 X 1.7 X 1.7 cm. Histologically, the tumor showed tubular adenoma with focal squamous metaplasia. Borderline atypia was noted in a part of adenoma without squamous metaplasia and squamous component. It is supposed that squamous epithelial polyp, squamous cell carcinoma, adenosquamous carcinoma, and mucoepidermoid carcinoma may be derived from colonic adenoma with squamous metaplasia. Only six cases of the adenoma with squamous metaplasia of the large intestine have been reported previously in the literature.

Adenoma↗
PubMed1984

Carcinoma with lymphoid stroma of the gallbladder--a case report.

A case of carcinoma with lymphoid stroma of the gallbladder is presented. Carcinoma of this type in the breast or the stomach is specified under the designation of carcinoma with lymphoid stroma or infiltration because of a relatively favorable prognosis. The characteristic morphological features are described and the significance of prognostic favorability is discussed together a short review of the literature. This seems to be the first documentation of such a case.

Aged↗
PubMed1984

Differential determination of cationic and anionic glutathione S-transferases by enzyme immunoassay.

Specific enzyme immunoassays for cationic and anionic glutathione S-transferases were established using the specific antibodies which were purified by antigen-bound adsorbent column chromatography. The enzyme immunoassay for cationic glutathione S-transferase had high specificity to cationic enzyme, but showed no cross reactivity with anionic one, and vice versa. The recovery of cationic glutathione S-transferase by the enzyme immunoassay was 94.7%, and coefficient of variation for within day and day-to-day precision were 7.8-10.4% and 8.5-12.5%, respectively. The enzyme immunoassay for anionic glutathione S-transferase also had a good recovery and precision. Using these enzyme immunoassays for glutathione S-transferases, sera of various patients were analyzed. Serum cationic glutathione S-transferase was increased in patients with hepatitis and hepatoma, and anionic glutathione S-transferase in serum was increased in patients with liver cirrhosis.

Animals↗
PubMed1984

A desktop computer to visualize the intraluminal velocity profile and its clinical application.

Based on our previous study that the outcome of reconstructive surgery for lower limbs could well be predicted by flow waveforms and that this state was defined by variation of wall shear stress (tau) in a cardiac cycle, we set up a desktop computer that could calculate wall shear stress in a given patient. This work is based on a principle of a computational method for simulating pulsating blood flow. The flow data from the patient are sent to the waveform analyzer, where the intraluminal velocity profile as well as the shear stress variation is demonstrated. Our study revealed no late occlusion in patients with flow waveforms over 70 dynes/cm2 in tau-variation, early graft failure in those below 20 dynes/cm2, and late occlusion in considerable numbers of patients whose waveforms were between 70 and 20 dynes/cm2. Intraoperative use of the waveform analyzer disclosed the occult cause of obstruction, which would otherwise be overlooked, leading to a remarkable decrease in the rate of immediate graft failure. Follow-up of outpatients with this approach facilitated early detection of late failure, making it possible to repair the graft with minor surgery. Use of the waveform analyzer proved superior to ankle pressure index in predicting graft failure.

Aged↗
PubMed1984

Antitumor activity of vitamin A and its derivatives.

Studies were conducted for investigation of the inhibitory effect on the development of experimental tumors of the skin and liver with vitamin A-like compounds, with a particular focus on a new synthetic derivative of the polyprenoic acid 3,7,11,15-tetramethyl-2,4,6,10,14-hexadecapentaenoic acid (E-5166). Incidence of skin papilloma, chemically induced in mice, was significantly influenced by dietary vitamin A contents. When given orally at a dose of 200 mg/kg body weight, beta-carotene regressed the skin papilloma to some extent (-16% at 14 days), although its effect was much weaker than that of E-5166 (-43%). E-5166 also significantly reduced tumor incidences of experimental hepatomas induced by chemical carcinogen in rats as well as in "spontaneous" hepatoma-bearing mice (C3H/HeNCrj) genetically determined. Further chemical studies revealed that retinol was locally deficient in the hepatomas but not in adjacent normal livers: In particular, anhydroretinol was newly detected in the tumors of spontaneous hepatoma-bearing mice, suggesting increased conversion of retinol into the inactive metabolite. Moreover, cellular retinoid-binding protein, F-type (an oncofetal protein), also newly appeared exclusively in the hepatoma tissues, suggesting that the preventive effect of E-5166 on hepatocarcinogenesis was mediated, at least in part, through its binding with the new retinoid receptor.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1984

Composite tumor (ordinary adenocarcinoma, typical carcinoid, and goblet cell adenocarcinoid) of the gallbladder: a variety of composite tumor.

This case may represent the first reported of a composite tumor with three neoplastic components in the literature. The tumor was composed of discrete areas of an ordinary adenocarcinoma, a typical carcinoid tumor, and a goblet cell adenocarcinoid. The unique case in the gallbladder is reported and the histogenesis of this rare tumor is discussed with a brief review of the literature.

Adenocarcinoma↗
PubMed1983

Effects of local anesthetics on calmodulin-dependent guanylate cyclase in the plasma membrane of Tetrahymena pyriformis.

A highly purified preparation of Tetrahymena calmodulin activated a membrane-bound guanylate cyclase by more than 40-fold. This activation of guanylate cyclase by calmodulin was inhibited completely by local anesthetics such as dibucaine, tetracaine, lidocaine and procaine at concentrations that had no appreciable effect on the activities of basal guanylate cyclase (without calmodulin) and adenylate cyclase. The inhibition by dibucaine of calmodulin-mediated activation of the enzyme activity was not reversed by calcium but was partially overcome by increasing the concentration of calmodulin. Kinetic analysis of local anesthetic-induced inhibition of activation of guanylate cyclase demonstrated a mixed type of antagonism. These results suggest the possibility that the inhibition of calmodulin-dependent guanylate cyclase resulted, in part, from interaction of the drugs with calmodulin.

Adenylyl Cyclases↗