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Biomedical subjects

M Murase

Publications and source records attributed to M Murase.

At least 73 records · Page 4Linked to original sources
PubMed1996

Serotyping and categorisation of Escherichia coli strains isolated between 1958 and 1992 from diarrhoeal diseases in Asia.

A total of 3065 strains of Escherichia coli isolated between 1958 and 1992 from patients with diarrhoea in different countries were examined for virulence factors by hybridisation with biotinylated DNA probes for genes that coded for production of heat-labile and heat-stable enterotoxins, enteroinvasiveness, production of verotoxins and attaching-and-effacing factor and were serotyped. Of the 3065 strains, 1998 were placed into one of four pathogenic categories by their virulence factors: 1057 enterotoxigenic E. coli (ETEC) comprising 30 O-groups, 73 serovars and 137 untypable strains; 132 enteroinvasive E. coli (EIEC) comprising 11 O-groups and 13 serovars; 64 verotoxin-producing E. coli (VTEC) comprising 11 O-groups, 17 serovars and 13 untypable strains; and 745 enteropathogenic E. coli (EPEC) comprising 34 O-groups, 92 serovars and 91 untypable strains. The remaining 1067 strains did not hybridise with any of the DNA probes used. About half the number of O-groups recognised were not restricted to a single pathogenic category, although the combinations of O- and H-antigens were different in each category.

Asia↗
PubMed1996

Effects of methyl 9(or 10)-hydroxy-10(or 9)-mercaptostearate and hexadecanethioic S-acid on cupric ion- or 2,2-azo-bis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidation of low density lipoprotein.

The preventive effects of two antioxidants, methyl 9(or 10)-hydroxy-10 (or 9)-mercaptostearate (SH-S) and hexadecanethioic S-acid (thiopalmitic acid, SH-Pal) against the oxidative modification of low density lipoproteins (LDL) induced by cupric ion or a water soluble initiator of peroxyl radicals, 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH), were studied by measuring thiobarbituric acid-reactive substances (TBARS). SH-S acted as an effective antioxidant in the oxidative modification of LDL induced by either cupric ion or AAPH. Interestingly, SH-S completely inhibited the formation of fluorescence products and decreased both the fluorescence and alpha-tocopherol content in LDL induced by cupric ion, and reduced 1,1-diphenyl 2-picrylhydrazyl (DPPH) used as a stable free radical model. The antioxidative effect was effectively prevented by the addition of increasing amounts of N-ethylmalemide (NEM) to the system. SH-Pal also inhibited the cupric ion-induced LDL oxidation, but showed little inhibitory effect on the AAPH-induced LDL oxidation. Moreover, SH-Pal was reduced to palmitic acid during the AAPH-induced LDL oxidation. These findings indicate that SH-S protects against oxidative damage of LDL in vitro, and that it acts as a free radical in peroxidation. In addition, this study shows that SH-Pal doesn't act as an efficient antioxidant in AAPH-induced lipid peroxidation.

Amidines↗
PubMed1996

Effects of propionate and ammonium on contractions produced by sodium removal in human internal mammary artery and saphenous vein.

Effects of propionate and ammonium on contractions produced by Na+ removal (0-Na+ contraction, replaced with N-methyl-D-glucamine) were studied and compared with those produced by 60 mM K+ in muscle strips isolated from human internal mammary artery (IMA) and saphenous vein (SV), clinically used as bypass vessels. Contractions induced by 60 mM K+ (60-K+ contractions) were similar in both vessels. 0-Na+ contraction was significantly larger in the vein than in the artery. Neither 60-K+ nor 0-Na+ contractions were significantly affected by NG-nitro-L-arginine (30 microM) or phenoxybenzamine (1 microM). Ouabain (2 microM) slowly potentiated 0-Na+ contractions and the 3rd contraction produced 60 min after ouabain application was 291 +/- 36% in the artery and 184 +/- 41% of the control (n = 10) in the vein. Propionate (20 mM) potentiated 60-K+ contraction more strongly in the vein than in the artery, but potentiation of 0-Na+ contraction was greater in the artery than in the vein. On the other hand, ammonium (20 mM) inhibited 60-K+ contractions more strongly in the artery than the vein, whereas inhibition of 0-Na+ contraction was stronger in the vein. 0-Na+ contraction is likely to be produced by an Na(+)-Ca2+ exchange mechanism, and the effects of propionate and ammonium are considered to be mediated by intracellular acidification and alkalinization, respectively. It is speculated that an Na(+)-H+ exchange may also be involved in 0-Na+ contraction and that SV has slightly lower pHi than IMA.

Adult↗
PubMed1996

Change in glucose homeostasis in rats by long-term magnesium-deficient diet.

It is widely known that hypomagnesemia is one of the symptoms observed in diabetic patients. This study was performed to assess the effect of chronic magnesium (Mg) deficiency on glucose metabolism in rats. Male Sprague-Dawley rats (at the age of four weeks) were given a Mg-deficient diet or a control diet for two to eight weeks. The rats were orally administered sucrose solution (2 g/kg BW) every two weeks, and blood was drawn from a tail vein before and 15 min after sucrose loading to determine the concentrations of blood glucose and plasma insulin. At the same time, other rats in a non-fasted condition were sacrificed by decapitation (rats sacrificed at eight weeks were rats used for sucrose loading). The epididymal fat pads were immediately removed and adipocytes were isolated. The amount of glucose transporter 4 (GLUT4) in the plasma membranes and low-density microsomal membranes prepared from the adipocytes was measured by immunoblotting to estimate the influence of chronic Mg deficiency on glucose metabolism at the cellular level. In addition, plasma biochemical parameters and muscle mineral contents were also evaluated. The glucose concentration in fasted blood was significantly lower in Mg-deficient rats than in control rats throughout the experiment period. The feeding of a Mg-deficient diet also attenuated the response of blood glucose and plasma insulin: the glucose level in blood tended to be lower in Mg-deficient rats at 15 min after oral sucrose administration, and the difference was significant at two and eight weeks. The plasma insulin level in Mg-deficient rats was also lower, reaching a significant difference at two weeks. When animals were sacrificed in a non-fasted condition at 2-week intervals, the plasma glucose level was also significantly decreased in Mg-deficient rats as compared to control rats throughout the experiment period. The plasma insulin level in non-fasted Mg-deficient rats was also significantly decreased at two and six weeks. The Mg-deficient diet increased plasma triglyceride, but the difference was significant only at four weeks, and plasma cholesterol remained unchanged. The plasma Mg level was markedly lower in Mg-deficient rats throughout the experiment period. In Mg-deficient rats, the Mg content in muscle was significantly reduced at two and eight weeks, whereas the calcium and sodium contents were significantly increased throughout the experiment period. In Mg-deficient rats, the degree of translocation of GLUT4 to plasma membranes in the adipocytes stimulated by insulin was reduced only at eight weeks. In conclusion, since fasted and non-fasted blood glucose levels and the response of blood glucose to sucrose loading were decreased in Mg-deficient rats, it is suggested that Mg deficiency induces changes in the glucose metabolism via impaired glucose absorption in the intestine or an altered glucose uptake in the liver and/or peripheral tissues.

Adipocytes↗
PubMed1996

[Case report of David's operation for annuloaortic ectasia and aortic regurgitation in a Marfan patient].

We report a 35-year-old Marfan patient who underwent David's operation for annuloaortic ectasia and aortic regurgitation. This new technique is done by excising the aneurysmal portion of the ascending aorta and sinuses of Valsalva but by leaving the aortic valve leaflets and some aortic wall attached to the left ventricular outflow tract inside the Dacron tube. Postoperative echocardiography revealed well coapted aortic valve leaflets and a very small amount of regurgitation. A rigid aortic route without sinuses of Valsalva may increase the mechanical stress on the leaflets and shorten their durability but this procedure have the advantage of so called Bentall's operation by preserving the native aortic valve.

Adult↗
PubMed1996

[Valve replacement concomitant with anulus reconstruction].

It is important that surgical treatment of infective endocarditis involves complete debridement of the affected tissue. In case of abscess formation in the mitral anulus and/or aortic root, disruption of the anulus occurs because of radical resection of the abscess. David et al. reported a new technique for mitral and aortic anulus reconstruction. The novel part of the technique was the endocardial repair, i.e., suturing of a pericardial patch to the endocardium of the left ventricle. We were surprised to learn that the left ventricular endocardium and muscle are capable of tolerating the stress induced by the prosthetic ring, especially in the mitral position. Since 1992, we treated eight cases of anulus disruption using this technique ; 5 cases involved the mitral anulus, 1 involved the aortic, and 2 involved both. We used a slightly different technique involving suturing of a patch not only to the left ventricular endocardium but also to left atrial wall for reinforcement. Two patients died in the perioperative period. One had a brain abscess ; the other had methicillin-resistant Staphylococcus aureus sepsis and mediastinitis. There was 1 late (sudden, unknown) death 3 years after the operation. No perivalvular leakage, dehiscence of the patch, hemolysis, prosthetic valve endocarditis, or thromboembolism have been observed in the other 5 patients.

Abscess↗
PubMed1996

[Influence of recirculation type blood cardioplegia on perfusion pressure in open heart surgery].

Infusion blood cardioplegia often decreases the perfusion pressure during open heart surgery. The blood level of bradykinin (BK) was measured in both the cardiopulmonary bypass (CPB) and blood cardioplegia circuit. Infusion cardioplegia with recirculation type circuit increased the BK level of cardioplegia and the perfusion pressure decreased abruptly with the increase BK level in the CPB circuit. In the case of single pass type circuit the BK level was not increased either in cardioplegia or CPB and perfusion pressure was not decreased. We concluded that the single pass type of cardioplegia circuit is superior to the recirculation type because of less production of BK.

Aged↗
PubMed1996

[Neoadjuvant chemotherapy in high-grade advanced gastric cancer with protracted infusional 5-fluorouracil and consecutive low-dose cisplatin].

Twenty-one evaluable patients with primary gastric cancer/local invasion, liver metastasis and peritoneal metastasis were entered in a pilot study of neoadjuvant chemotherapy that used continuous 24-hour infusion 5-FU, 330 mg/m2/day plus low dose CDDP, 6 mg/m2 daily by bolus infusion d1-5. This regimen was repeated for 4 weeks. The overall response rate was 52%, including one complete and ten partial responses. The response rate of differentiated adenocarcinomas was significantly higher than that of poorly differentiated adenocarcinomas. In 15 patients (71%), gastrectomy and lymphadenectomy could be done after this regimen. chemotherapy-induced downstaging from the initial clinical stage was pathologically found in 5 patients who underwent gastrectomy. Toxicity was primarily hematologic. Leukopenia and thrombocytopenia of grade 3 or 4 occurred in 19% and 14% of patients, respectively. The patients were able to take meals during therapy and preserved good quality of life. Median survival time was 11 months for the cancers with liver metastasis and five of the 8 locally advanced cancers are alive 11 months after the therapy. This therapy was effective for patients with high-grade advanced gastric cancer.

Adenocarcinoma↗
PubMed1995

Compositions of very low density lipoprotein subfractions from patients with polydisperse low density lipoproteins.

In some hyperlipidemic patients, low density lipoprotein (LDL) shows several peaks (polydisperse) on polyacrylamide gel disc electrophoreses, though LDL usually shows a single peak (monodisperse). In order to clarify the relationship between the LDL polydispersion and VLDL heterogeneity, LDL and VLDL were prepared from hyperlipidemic patients sera with mono- and polydisperse LDL by sequential ultracentrifugation and fractionated by gradient ultracentrifugation and their compositions were analyzed. Polydisperse LDL was rich in triacylglycerol (TG) and poor in esterified cholesterol (CE) as compared with monodisperse LDL and consisted of the lowest and the medium density subfractions when the LDL was separated into six subfractions. The monodisperse LDL was composed of a single major subfraction of a medium density. VLDL from the patients with polydisperse LDL was relatively rich in the dense and poor in the buoyant subfractions as compared with that from the patients with monodisperse LDL. The subfractions in the former contained more CE and less TG than the corresponding subfractions in the latter. There were no significant differences in the apolipoprotein compositions between those VLDLs. The results suggest that polydisperse LDL might be originated from VLDL that differs in particle sizes, densities and compositions from ordinary VLDL.

Adult↗
PubMed1995

Determination of portal short-chain fatty acids in rats fed various dietary fibers by capillary gas chromatography.

A simple, rapid and sensitive capillary gas chromatographic method was investigated to measure portal short-chain fatty acids (SCFAs). A 20-microliters sample of portal plasma was denatured with sulfosalicylic acid and then extracted with diethyl ether before the removal of protein precipitate. The resultant extract was concentrated by a transfer to 50 microliters of 0.2 M NaOH, thus avoiding tedious further concentration steps. This reduced the sample volume to one-fourth. Since the ratio of acetic acid, a major SCFA, to other acids varies widely, ranging from 10-fold to 100-fold, acrylic and methacrylic acids were used as internal standards to simultaneously measure SCFAs having a carbon number of 2-6. As a result, good recovery (90.38-103.17%) and reproducibility (coefficient of variation 0.83-8.85%) were observed over a wide range. Furthermore, portal SCFAs in rats fed various dietary fibers were determined by the present method. We showed that the amounts not only of the major acids such as acetic acid and propionic acid, but also of the minor fermented products such as n-valeric acid and n-caproic acid, could be significantly changed by dietary manipulation. Thus, the present method is simple and reliable, and requires only a small amount of sample.

Animals↗
PubMed1995

A new device for exposing the circumflex coronary artery.

We have devised a new retractor for use in coronary artery bypass grafting that is made from three woven Teflon tapes. This method allows sufficient counterclockwise rotation of the heart, provides excellent exposure of the posterior and inferior coronary artery systems, and creates a horizontal surgical plane for the circumflex anastomosis.

Coronary Artery Bypass↗
PubMed1995

Left atrial function after Cox's maze operation concomitant with mitral valve operation.

BACKGROUND: This study examined whether the atrial fibrillation that commonly occurs in patients with a mitral valve operation could be eliminated by a concomitant maze operation. METHODS: Left atrial function after Cox's maze operation performed concomitantly with a mitral valve operation was evaluated in 10 patients ranging in age from 38 to 67 years (mean age, 54 years). Seven patients who had had coronary artery bypass grafting served as the control group. Using transthoracic echocardiography, the ratio between the peak speed of the early filling wave and that of the atrial contraction wave (A/E ratio) and the atrial filling fraction (AFF) were determined from transmitral flow measurements. These two indices have been considered to represent the contribution of left atrial active contraction to ventricular filling. RESULTS: The A/E ratio and the AFF were significantly lower in the maze group (0.35 +/- 0.17 versus 0.97 +/- 0.28 [p < 0.01] and 17.6% +/- 8.8% versus 36.8% +/- 6.4% [p < 0.01], respectively). The A/E ratio and the AFF correlated inversely with age (r = -0.72, p < 0.05 and r = 0.76, p < 0.05, respectively) in the maze group. In an angiographic study, the mean left atrial maximal volume index in the maze group was approximately three times larger than that in the control group (117.5 +/- 24.3 mL/m2 versus 35.3 +/- 6.6 mL/m2 [p < 0.01]). The left atrial active emptying volume index was significantly smaller in patients in the maze group (7.2 +/- 2.5 mL/m2 versus 13.1 +/- 4.6 mL/m2 [p < 0.01]). CONCLUSIONS: After the maze procedure performed concomitantly with a mitral valve operation in patients with a dilated left atrium, left atrial contraction is detectable but incomplete in the elderly.

Adult↗
PubMed1995

Regional cerebral tissue blood flow measured by the colored microsphere method during retrograde cerebral perfusion.

Brain tissue blood flow was measured precisely by the colored microsphere method during retrograde cerebral perfusion in 10 normothermic mongrel dogs. The average tissue blood flow rates to the cerebral cortex, cerebral medulla, brain stem, cerebellum, and spinal cord during retrograde cerebral perfusion at 25 mm Hg of external jugular venous pressure were 10.5 +/- 10.3, 4.2 +/- 4.6, 11.1 +/- 9.8, 12.3 +/- 8.6, and 9.1 +/- 5.8 ml/min per 100 gm, respectively. The brain was perfused wholly by retrograde cerebral perfusion without lateralization. Total cerebral blood flow was calculated as the sum total rates of blood flow to each area. Total cerebral blood flow during retrograde cerebral perfusion at 25 mm Hg was 7.8 +/- 4.4 ml/min, which represented 3.5% +/- 1.9% of whole body blood flow and one third of the total cerebral blood flow (28.0 +/- 4.2 ml/min) during cardiopulmonary bypass at a flow rate of 1000 ml/min. Oxygen consumption and carbon dioxide elimination by the total cerebrum during retrograde cerebral perfusion at 25 mm Hg were 0.54 +/- 0.23 ml/min and 34 +/- 15 mumol/min, respectively, or 8.6% +/- 3.6% and 7.0% +/- 3.1% of the corresponding whole body value and represented about one third of that measured during cardiopulmonary bypass (1.21 +/- 0.39 ml/min and 96 +/- 15 mumol/min). Total cerebral blood flow, total cerebral oxygen consumption, and carbon dioxide elimination increased as the external jugular venous pressure increased from 15 to 25 mm Hg; however, no further increase occurred once the external jugular venous pressure exceeded 25 mm Hg.

Animals↗
PubMed1995

[Operative procedures for mitral prolapse and its clinical results].

Mitral valve plasty is the very important procedure for treatment of mitral regurgitation from the view point of post operative quality of life because patients may be possible to be free from postoperative drug therapy especially when the normal sinus rhythm is restored even if the concomitant maze procedure is necessary. In this report, 36 patients who underwent mitral valve plasty for mitral regurgitation were evaluated. In 18 patients who had posterior leaflet prolapse, McGoon's procedure was performed. Two of them required secondary mitral valve replacement 4 days after operation. Reoperation disclosed tissue detachment at the mitral annulus sutures which were not reinforced by a ring. It was considered that annular ring plasty is preferable after resection of prolapsed posterior leaflet by McGoon's procedure. Out of 18 patients who had mitral valve prolapse including anterior leaflet, 8 patients underwent such conventional procedures as transfer of chordae tendinae, leaflet resection and shortening of chordae. Four patients resulted in second look mitral valve replacement 11 days to 1 month after mitral valve plasty. On the contrary, the clinical results of repair of chordae tendineae with artificial chordae of extended polytetrafluoroethylene (ePTFE) were good. It is concluded that the resection of prolapsed leaflet and reconstruction of the annulus with reinforcement using a prosthetic ring is preferable for the posterior leaflet prolapse. For the anterior leaflet prolapse, good results can be obtained by replacement of chordae tendineae with ePTFE sutures.

Adolescent↗
PubMed1995

[Repair of mitral valve prolapse by resection and sliding plasty].

There have been many techniques applied to the repair of mitral valve prolapse, and the method used in a particular case is usually selected according to the position and extent of the lesion. To simplify and standardize the technique of mitral valve repair, we have adopted the resection, sliding plasty and ring annuloplasty methods since December 1992. Of 10 consecutive surgical cases, 2 involved prolapse of the anterior leaflet, 1 the posteromedial commissural, and 7 the posterior leaflet. One patient with posterior leaflet prolapse required valve replacement due to dehiscence of the plastied site on the 3rd postoperative day, and one died because of sepsis. However, the remaining patients were doing well without mitral regurgitation at a mean of 20 months (range: 8-32) after the operation. The advantages of these techniques include easy adjustment of the height of the leaflet and a good chance of long-term durability, since the affected lesion is resected.

Adult↗
PubMed1995

[One-stage repair of interrupted aortic arch with ventricular septal defect].

Three neonates with type A interrupted aortic arch were successfully repaired through a median sternotomy incision during profound hypothermia and circulatory arrest in the past one year. Two aortic cannulas, a small plastic one (Cardicorp) in the ascending aorta and a long one inserted through the pulmonary artery and patent ductus arteriosus into the descending aorta. Two Pacifico's venous cannulas were inserted into superior and inferior vena cavae respectively. No dissection and encircling were required around three major branches from the aortic arch and both right and left pulmonary arteries. During a cooling phase a large ventricular septal defect was closed followed by circulatory arrest. It was possible to resect a patent ductus arteriosus and mobilize the descending thoracic aorta for anastomosis to the side of the ascending aorta without removal of the aortic cannula in the aorta. New instruments and development of cardiopulmonary bypass could bring a successful one-stage repair of interrupted aortic arch with ventricular septal defect more safely and easily than before.

Aorta, Thoracic↗