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Biomedical subjects

Y Sakurai

Publications and source records attributed to Y Sakurai.

At least 289 records · Page 16Linked to original sources
PubMed1995

The failure of retrograde continuous warm-blood cardioplegia to resuscitate cardiac function in experimental acute coronary artery occlusion and reperfusion.

The effects of retrograde continuous warm-blood cardioplegia (RCWBC) on myocardial preservation during surgical revascularization for acute coronary artery occlusion were investigated using an isolated in-situ dog heart model. The left anterior descending artery (LAD) was occluded for 60 minutes followed by 60 minutes of cardioplegic arrest and reperfusion after release of the coronary artery occlusion. Thirty one animals were divided into 3 groups according to the manner of cardioplegic arrest. The first group of animals (n=10) received multiple doses of cold St. Thomas' Hospital solution delivered antegradely through the aortic root. The second group of animals (n=11) received the same dose of the crystalloid solution delivered retrogradely through the coronary sinus. The third group of animals (n=10) received RCWBC through the coronary sinus. In the animals which were capable of supporting the working mode after reperfusion (8 hearts in each group), regional myocardial function in the occluded LAD distribution measured by sonomicrometer as well as global myocardial function evaluated by left-ventricular stroke-work index were not significantly improved during reperfusion by RCWBC. Corresponding to the functional data, myocardial pH in the occluded LAD distribution was not significantly increased by RCWBC. Although RCWBC maintained myocardial pH in the circumflex artery distribution at a significantly higher level than the other two groups of hearts undergoing cold crystalloid cardioplegia, RCWBC resulted in a substantial decline of myocardial pH in the right-ventricular free wall. These results suggest that RCWBC after 60 minutes of LAD occlusion may not provide a significant benefit in myocardial preservation compared to cold crystalloid cardioplegia delivered through either an antegrade or retrograde manner.

Animals↗
PubMed1995

Novel sensing system for glucose based on the complex formation between phenylborate and fluorescent diol compounds.

From the standpoints of long-term stability and simple handling, a glucose sensor composed of totally synthetic sensing moieties should be of great advantage. This study was performed to demonstrate the feasibility of a novel glucose sensing system in an aqueous milieu based on a change in the fluorescence on competitive binding between a fluorescent diol compound and glucose toward a phenylborate compound. 6,7-Dihydroxy-4-methyl-coumarin (DHMC) was selected as a fluorophore, and 3-propionamidophenylboronic acid (PAPBA) as a phenylborate compound. The relationship between the glucose concentration and fluorescence intensity was linear in the range of 0 to 500 mg/dl of glucose. The availability of various derivatives of DHMC and phenylborate compounds allows the incorporation of these functionalities on the tip of an optical fiber to construct an opto-sensing system for glucose.

Boronic Acids↗
PubMed1995

Stimulation of muscle protein synthesis by long-term insulin infusion in severely burned patients.

OBJECTIVE: To determine if long-term (7 days) infusion of insulin can ameliorate altered protein kinetics in skeletal muscle of severely burned patients and to investigate the hypothesis that changes in protein kinetics during insulin infusion are associated with an increased rate of transmembrane amino acid transport from plasma into the intracellular free amino acid pool. SUMMARY BACKGROUND DATA: In critically ill patients, vigorous nutritional support alone may often fail to entirely curtail muscle catabolism; insulin stimulates muscle protein synthesis in normal volunteers. METHODS: Nine patients with severe burns were studied once during enteral feeding alone (control period), and once after 7 days of high-dose insulin. The order of treatment with insulin was randomized. Data were derived from a model based on a primed-continuous infusion of L-[15N]phenylalanine, sampling of blood from the femoral artery and vein, and biopsies of the vastus lateralis muscle. RESULTS: Net leg muscle protein balance was significantly (p < 0.05) negative during the control period. Exogenous insulin eliminated this negative balance by stimulating protein synthesis approximately 350% (p < 0.01). This was made possible in part by a sixfold increase in the inward transport of amino acids from blood (p < 0.01). There was also a significant increase in leg muscle protein breakdown. The new rates of synthesis, breakdown, and inward transport during insulin were in balance, such that there was no difference in the intracellular phenylalanine concentration from the control period. The fractional synthetic rate of protein in the wound was also stimulated by insulin by approximately 50%, but the response was variable and did not reach significance. CONCLUSIONS: Exogenous insulin may be useful in promoting muscle protein synthesis in severely catabolic patients.

Adolescent↗
PubMed1995

The relation of smoking, alcohol use and obesity to risk of sigmoid colon and rectal adenomas.

We conducted a case-control study, using 429 cases with histologically confirmed sigmoid adenoma, 75 cases with rectal adenoma, and 3101 controls showing normal colonoscopy at least up to 60 cm from the anus. The subjects were male Self-Defense Forces personnel aged 48-56 who received a retirement health examination including a routine sigmoid- or colonoscopy. Lifestyle characteristics were ascertained by a self-administered questionnaire. Smoking in the recent past (< or = 10 years preceding the colonoscopy) and smoking in the remote past (> 10 years before the colonoscopy) were both significantly associated with risk of sigmoid adenoma but not with rectal adenoma as a whole. After reciprocal adjustment for smoking in the two periods, only smoking in the recent past was associated with both sigmoid colon and rectal adenomas. Odds ratios (OR) of sigmoid adenoma (and 95% confidence interval) for the categories of 0, 1-150, 151-250 and > or = 251 cigarette-years were 1.0 (reference), 1.9 (1.3-2.8), 2.1 (1.4-3.0) and 3.0 (1.9-4.7), respectively (P for trend < 0.01), and those for rectal adenoma were 1.0 (reference), 1.2 (0.4 3.2), 3.5 (1.4-8.5) and 2.0 (0.6 6.7), respectively (P for trend = 0.03). Alcohol use was significantly positively associated with sigmoid adenoma, and insignificantly associated with rectal adenoma. Body mass index was significantly positively associated with sigmoid adenoma, especially large ones. No such association was found for rectal adenoma. These findings suggest that smoking, especially in the recent past, and alcohol use are common risk factors for sigmoid colon and rectal adenomas while obesity may be exclusively related to the growth of sigmoid adenoma.

Adenoma↗
PubMed1995

Cytoplasmic calcium level and membrane fluidity of platelets contacting poly(acrylamide-co-methacrylic acid) particles with different surface properties.

Changes in cytoplasmic free calcium levels and membrane fluidity of platelets in contact with poly(acrylamide-co-methacrylic acid) (PAAmMAc) particles were examined to analyze the mechanistic aspect of regulating platelet function. Our previous studies demonstrated interesting features of PAAmMAc particles during interaction with platelets: (1) PAAmMAc particles induce no calcium increase but enhance membrane fluidity of platelets: (2) thrombin induces no calcium increase in platelets when the platelets were mixed previously with PAAmMAc particles; and (3) PAAmMAc particles induce a calcium increase in platelets when they were treated previously with sodium azide (NaN3). These results suggest the possibility that PAAmMAc surfaces may regulate the calcium level by influencing platelet metabolism. In this study, non-cross-linked PAAmMAc solution with the same chemical composition as the particles showed a suppressive effect on thrombin-induced calcium increase, but, no influence on membrane fluidity. This result indicates that aggregated macromolecular surface assemblies of PAAmMAc may dominate the increase in membrane fluidity of platelets although the calcium change is induced by discrete molecular level interaction between the PAAmMAc and platelet membranes. It was also revealed that the suppression of thrombin-induced calcium increase and the membrane fluidity increase in platelets by PAAmMAc particles were reduced by albumin-treatment of the particles. This result suggests that such phenomena may be due to a decrease in any physicochemical interaction of PAAmMAc surfaces with albumin, rather than platelet metabolic change. PAAmMAc particle surfaces with higher carboxyl groups exhibited a more suppressive effect on thrombin-induced calcium increase, whereas those with lower carboxyl groups derived a higher calcium increase when the platelets were treated previously with NaN3. These results suggest the importance of electrostatic and any other physicochemical interaction of PAAmMAc chains on regulating cytoplasmic calcium levels.

Acrylic Resins↗
PubMed1995

Endothelial cell differentiation into capillary structures by copolymer surfaces with phenylboronic acid groups.

A ternary copolymer composed of m-acrylamidophenylboronic acid, N,N-dimethylaminopropylmethacrylamide and N-isopropylacrylamide was synthesized. Long-term culture of bovine aortic endothelial cells on this copolymer substrate demonstrated adhesion and proliferation of the cells. After 26 days in culture, endothelial cells spontaneously developed into capillary networks. The interactions between phenylboronic acid groups in copolymer and glycoconjugates on endothelial cell plasma membranes are proposed to regulate the induction of tissue formation, since phenylboronic acid groups are known to specifically form reversible complexes with cis-diol compounds such as glucose. This copolymer is a novel material capable of mediating specific signals analogous to extracellular matrix to promote proliferation of endothelial cells, inducing capillary structures and prompt angiogenesis.

Acrylamides↗
PubMed1995

The secular trend in the incidence of subarachnoid hemorrhage in Miyagi, Japan: 1979-1990.

Since 1978, a stroke registry has been carried out in Miyagi Prefecture (2.2 million in population), Japan. Approximately 2,000 cases of stroke were annually registered through 16 hospitals which have cerebrovascular disease units. The incidence of subarachnoid hemorrhage was 17.4 per 100,000 population in 1990. The incidence increased gradually during early 1980's and reached plateau during late 1980's. Further, the trend in the incidence of subarachnoid hemorrhage is compared with those in other communities in other countries as well as Japan.

Adolescent↗
PubMed1995

Gallstone disease among Japanese men in relation to obesity, glucose intolerance, exercise, alcohol use, and smoking.

BACKGROUND: Risk factors for gallstones are not fully understood, especially in men. Obesity and other risk factors for gallstone disease were investigated in Japanese men based on gallbladder ultrasonography. METHODS: Forty-one men with gallstones, 31 with postcholecystectomy state, and 2044 with a normal gallbladder were identified among 2228 men aged 49-55 years who received a retirement health examination at three hospitals of the Japan Self-Defense Forces between 1991 and 1992. Glucose tolerance was determined with a 75-g oral glucose tolerance test. RESULTS: Body mass index was not associated with gallstones, although it was significantly, positively related to postcholecystectomy. Waist to hip circumference ratio tended to be weakly associated with gallstones. Diabetes mellitus was associated only with postcholecystectomy. Smoking, alcohol intake, and physical activity were not measurably related to either gallstones or postcholecystectomy. CONCLUSIONS: The present study failed to substantiate an association of gallstone risk with either obesity or any other risk factor. Further observation is needed in view of the limited study power.

Alcohol Drinking↗
PubMed1995

Transthird ventricular approach for a high basilar bifurcation aneurysm. Report of three cases.

Three cases of ruptured aneurysm at the basilar bifurcation accompanied by megadolichobasilar anomaly were successfully treated using a transthird ventricular approach. A translamina terminalis approach was used to enter the third ventricle. In two cases, the floor of the third ventricle had been partly destroyed by aneurysm rupture, and a small split in the third ventricular floor was necessary to gain a wide operative field. In the third case, an intact floor was opened along the midline. Clipping was accomplished in all three cases after preserving the perforating arteries. Postoperatively, no complications from splitting the floor were observed. Key surgical points and the prospective view of the transthird ventricular approach are discussed.

Aged↗
PubMed1995

[Pure word deafness after cerebral hemorrhage in the left temporal lobe: a case report].

We report a patient with pure word deafness after subcortical hemorrhage in the left temporal lobe. Repetition and auditory comprehension were severely impaired, while reading and visual comprehension of the same material were almost normal. He did not show hearing loss, but speech discrimination and melody recognition was poor. On the speech discrimination test, his score was low especially in the right ear. The threshold on the directional hearing test was mildly elevated. There was no temporal summation by click sounds. CT and MRI disclosed a subcortical hematoma in the left superior temporal gyrus. PET demonstrated hypoperfusion in the surrounding area, which was not activated by hearing a story. It was considered that pure word deafness in this case was due to the interruption of auditory inputs to Wernicke's area from both hemisphere by the hematoma. After 5 months, auditory comprehension recovered so that he did not have difficulty in conversation. Speech discrimination improved in both ears, probably due to the recovery of two auditory pathways; the ipsilateral pathway through the left auditory radiation and the contralateral pathway through the right auditory radiation and the corpus callosum. This case suggests that in pure word deafness due to a unilateral lesion, the improvement in speech discrimination during follow-up period may provide a clue as to the site of the responsible lesion and its recovery.

Aged↗
PubMed1995

[A neonate case of dural arteriovenous shunt presenting with cerebellar hemorrhage].

A rare case of dural arteriovenous shunt (dAVS) manifested as cerebellar hemorrhage in a neonate is reported. Seven days after birth, a neonate was referred to our hospital because of consciousness disturbance. CT scan revealed cerebellar hemorrhage, subarachnoid hemorrhage, subdural hematoma, and a high density mass lesion at the torcular herophili. Retrograde brachial angiogram failed to show any vascular lesions. He underwent an evacuation of the cerebellar hematoma. Postoperative course was uneventful. However, at the age of four months, he was admitted again because of consciousness disturbance and cardiac failure. CT scan revealed hydrocephalus and an enlarged mass lesion at the torcular herophili. Angiogram disclosed dural AVS. Its feeding arteries were as follows; the bilateral middle meningeal arteries (MMA), the occipital arteries (OA), dural branches of the bilateral posterior inferior cerebellar arteries, arteries consisting of transdural anastomosis from the left posterior cerebral artery. The arterial flow from these feeding arteries was shunting directly to the torcular herophili, the posterior part of the superior sagittal sinus, and the straight sinus. He underwent a venticulo-peritoneal shunting. Then, after treatment for cardiac failure, superselective embolization of the bilateral MMAs and the OAs resulted in diminution of shunting flow. The initial onset of this case was at seven days after his birth. Dural AVS is very rare in the pediatric population, particularly in the neonate. The clinical features, pathogenesis, and the treatment for this rare entity are discussed.

Arteriovenous Malformations↗
PubMed1995

[Thoracoscopic treatment of a giant bulla: a case report].

A 38-year-old man was admitted to our hospital because of left giant bulla and pneumothorax. His chest X-rays and CT scan showed giant bulla of the left upper lobe and left pneumothorax. We performed bullectomy using the ENDOPATH ENDO LINEAR CUTTER 60 mm and 35 mm disporsable surgical stapler under thoracoscopic guidance. Clipping with end-clips and fibrin glue were effective for miner air leakage. There were no complications such as prolonged air leakage or incomplete lung re-expansion. His post operative couse was uneventful and he was discharged from the hospital on the 11th post operative day. When performed along with mini-thoracotomy, thoracoscopic operation is useful in treating patients with giant bulla.

Adult↗
PubMed1995

[Studies on neural mechanisms of memory in rats--present and future trends].

Neuroscience research of memory using rats behavior is bringing the behavioral studies and the recent molecular neurobiological findings closer to each other. Careful construction of behavioral tasks for rats is necessary first. Concerning the brain regions for memory, the hippocampus has been and is the most critical one. Consideration of psychological frameworks to see the hippocampal functions in memory, i.e., spatial memory, working and reference memory, configural association, entorhinal-hippocampal interplay, and long-term potentiation, are also necessary. To improve the significance of studies with rats, methods of making hippocampal lesions should be improved. Also, easy following the findings of studies with monkeys, visual-dominant animals, should be avoided. Research trying to find basic manners of information processing of memory in the brain rather than functional maps and systems may be adequate for studies with rats. The concept of "cell assemblies" for memory processing in the rat was introduced.

Animals↗
PubMed1995

Effects of probenecid and cimetidine on the renal excretion of 3'-azido-3'-deoxythymidine in rats.

The mechanisms underlying the inhibitory effects exerted by probenecid and cimetidine on the renal excretion of 3'-azido-3'-deoxythymidine (AZT) were investigated in rats in vivo. On i.v. administration, the findings indicated that both probenecid and cimetidine increased the plasma concentration of AZT and inhibited its renal excretion. To clarify the mechanisms underlying the interaction of these drugs with AZT and to elucidate the process of renal secretion of AZT, further investigation was performed, in which [3H]AZT (0.5 microM) was injected rapidly into the right renal artery, and its outflow profile from the right ureter was compared with that from the left ureter. In control experiments, 56.6% of the administered AZT was secreted from the right kidney, and it was calculated that the transcellular transit time of AZT in this process was 0.30 min. In the presence of 10 mM probenecid and of 10 mM cimetidine, the secretion of AZT was reduced to 15.3 and 32.3%, respectively, the inhibition induced by probenecid being more effective than that induced by cimetidine. However, the transcellular transit time of AZT increased to 0.53 and 1.21 min in the probenecid and cimetidine studies, respectively. Thus, cimetidine was more potent than probenecid in its effects on the transit time. These findings indicate that probenecid and cimetidine affect different steps in the renal secretion of AZT. It was therefore concluded that, on the renal plasma membrane, AZT is transported by anion transport systems, whereas on the brush border membrane, AZT is secreted by cation transport systems.

Animals↗
PubMed1995

[Interferon treatment for chronic hepatitis C--assessment of 3 regimens in patients received more than 500MU interferon treatment and their effect predictive factors for interferon treatment using multivariate analysis with the logistic regression model].

Chronic hepatitis C patients (n = 115) were treated with interferon (IFN). Total dose employed was more than 500 MU. The response rate was assessed among the three treatment groups: 2W continuous+TIW, 4W continuous+TIW, 8W continuous+TIW. The IFN treatment effect predictive factors were also assessed. Complete response (CR) rate, CR with serum HCV-RNA disappearance rate, responders' histology activity index score changes between before and after treatment, and responders' hepatocytes HCV-RNA disappearance rate did not differ among the three treatment regimens. CR to IFN treatment was dependent on serum HCV-RNA and HCV serotype. Patients of low serum HCV-RNA and serotype II were responsive to IFN treatment.

Chronic Disease↗
PubMed1995

[Experiences of the approaches to heart for a patient with a tracheostoma].

The performance of open heart surgery in a patient with a tracheostoma can present difficult problems, including postoperative mediastinitis and inadequate operative exposure. Recently, we experienced two cases in which tracheostomy had been done preoperatively due to heart failure and reported the satisfactory results in this paper. Case 1; A 59-year-old woman who had mitral stenosis and massive regurgitation received mitral valve replacement and left atrial raphy. The approach to heart was performed in according to the following. A transverse submammary skin incision was made from right anterior axillar line to left mammary line and then a bilateral thoracotomy was made at the fourth intercostal space. Case 2; A 73-year-old man who had old myocardial infarction and postinfarction angina received coronary artery bypassgrafting to right coronary artery and left anterior descending branch, using saphenous vein grafts. A skin incision was placed at the second intercostal space in the fashion of "collar skin incision" and then made from the center of collar skin incision to the xiphoid process. The sternum was transected at the second intercostal space and divided longitudinally to the xiphoid process. These two approaches provided the adequate operative field. The cannulation of the ascending aorta, the superior vena cava and the inferior vena cava presented no difficulty and the operative procedure could be performed easily in a routine manner. We think that in a case of open heart surgery of a patient with a tracheostoma the approach in which the skin incision is distant from the area of a tracheostoma and no dissection near a tracheostoma is necessary have to be selected in order to decrease the risk of postoperative wound infection and mediastinitis.

Aged↗
PubMed1995

Relation of waist-hip ratio to glucose tolerance, blood pressure, and serum lipids in middle-aged Japanese males.

OBJECTIVE: To investigate whether waist-hip ratio (WHR) influences glucose tolerance, blood pressure, and serum lipids independently of body mass index (BMI). DESIGN: Cross-sectional study. SUBJECTS: 2,228 male self-defense officials aged 49-55 years in Japan. MEASUREMENTS: BMI, WHR, serum lipids, systolic and diastolic blood pressure, and glucose tolerance status according to World Health Organization (WHO) criteria. RESULTS: Adjustment was made for smoking, alcohol use, physical activity, and inter-hospital variation in statistical analysis. Adjusted odds ratios of non-insulin-dependent diabetes mellitus (NIDDM) were progressively increased with increasing levels of WHR, but not BMI. Both BMI and WHR were independently positively associated with impaired glucose tolerance to almost the same degree. Adjusted means of blood pressure, total cholesterol, and triglycerides were almost linearly increased with increasing levels of both BMI and WHR, and high-density lipoprotein cholesterol was progressively decreased. Although the associations of BMI and WHR with blood pressure and serum lipids attenuated after mutual adjustment for each, BMI was less influenced by WHR than vice versa, except for triglycerides. CONCLUSION: WHR is an important contributor not only to NIDDM but also to impaired glucose tolerance, blood pressure, and serum lipids, although the associations of WHR with blood pressure and serum lipids were generally weaker than those of BMI, except for triglycerides.

Blood Pressure↗