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Biomedical subjects

T Isomura

Publications and source records attributed to T Isomura.

At least 73 records · Page 4Linked to original sources
PubMed1995

Proteoglycan synthesis by chicken corneal explants.

Corneal explants with scleral rims were freshly prepared from 3-day-old hatched chicks, cultured in vitro for 5 h in the presence of [35S]sulfate and [3H]glucosamine, then the constituent tissues (stroma, epithelium, endothelium, and corneo-scleral rim) were dissected from the explants. Incorporation of 35S activity into stromal tissue was the highest among the constituent tissues (54% of the total). Two predominant proteoglycans were identified in the stromal fraction: keratan sulfate proteoglycan and chondroitin sulfate/dermatan sulfate proteoglycan. Whereas heparan sulfate proteoglycan was found in epithelial tissue as the major proteoglycan therein, it was a minor component in the other tissues. In contrast, most of the 35S-labeled material in the culture medium was the sulfated glycoprotein, which was probably synthesized and secreted by epithelial cells. When each constituent tissue was separately cultured in the presence of radioactive precursors, incorporation of radioactivities into each tissue decreased markedly compared with those into the respective tissues obtained by dissection after culture of the whole cornea with scleral rim. This suggests that corneal constituent tissues interact with each other for proteoglycan synthesis. But the glycosaminoglycan compositions of stromal proteoglycans synthesized in stroma cultured alone and in stroma from the cultured cornea with scleral rim were similar to each other; the two major glycosaminoglycans were chondroitin sulfate/dermatan sulfate and keratan sulfate. In contrast, when stromal tissue was cultured alone, most of the 35S-labeled material in the culture medium was keratan sulfate proteoglycan and free keratan sulfate chain, suggesting that keratan sulfate species are catabolized and eliminated more readily from collagen lamina than chondroitin sulfate/dermatan sulfate species, unless the corneal stroma is surrounded with other tissues. Whereas keratan sulfate was not detected in epithelium cultured alone, a small amount of it was found in endothelium cultured alone.

Animals↗
PubMed1995

Beneficial effect of steroid on myocardial preservation in isolated rat hearts.

Myocardial injury after heart storage has been known to contribute to an increase in myocardial calcium content or oxygen free radical production. The present experiment was designed to determine the inhibitory effect of steroid in the preservation solution on myocardial injury during simple immersion of isolated rat hearts. The experimental group was divided into 5 sub-groups according to the concentration of steroid added to the solution. Group I was stored in preservation solution containing no steroid. Groups II to V were stored in preservation solutions containing methylprednisolone in concentrations of 50 mg/L, 100 mg/L, 150 mg/L, and 200 mg/L, respectively. After the rat hearts were isolated, crystalloid cardioplegic solution at 4 degrees C was used for cardiac arrest, and the hearts were immersed in 4 degrees C Euro-Collins solution for 8 h. Hearts were then maintained under ischemic conditions at 25 degrees C for 15 min. After 60 min of reperfusion at 37 degrees C, cardiac function was measured and biochemical analyses of coronary effluent and myocardium were performed. The cardiac outputs in groups IV and V were significantly higher than those in groups I and II (p < 0.01). Creatine kinase-MB in coronary effluent in groups IV and V were significantly lower than those in groups I and II at 15, 30 and 60 min after reperfusion (p < 0.05). The level of arachidonic acid at 1 and 5 min, and the level of malondialdehyde at 5 min, after reperfusion in groups III, IV and V were significantly lower than those in groups I and II. Myocardial adenosine triphosphate was most preserved in group IV, and myocardial arachidonic acid, malondialdehyde, and calcium levels and water content in groups IV and V were lower than those in groups I and II. Ultrastructural observations also showed that myofilaments and mitochondria were well preserved in groups III, IV and V at 15 min after reperfusion compared with those in groups I and II. These results indicate that the addition of steroid to preservation solution might be effective in preventing myocardial injury during preservation of rat hearts, and the optimal concentration appears to range from 150 mg/L to 200 mg/L.

Actin Cytoskeleton↗
PubMed1995

[CT findings of pancreatic carcinoma: evaluation with the combined method of early enhancement CT and high dose enhancement CT].

Computed tomographic (CT) findings of pancreatic ductal adenocarcinoma were studied with the combined method of early enhancement CT and high dose enhancement CT in 72 carcinomas. Common Findings were change in pancreatic contour, abnormal attenuation in a tumor and dilatation of the main pancreatic duct. The incidence of abnormal attenuation and dilatation of the main pancreatic duct and bile duct was constant regardless of tumor size. The finding of hypoattenuation at early enhancement CT was most useful for demonstrating a carcinoma. However, this finding was negative in ten cases, five of which showed inhomogenous hyperattenuation at high dose enhancement CT. The detection of change in pancreatic contour and dilatation of the main pancreatic duct was most frequent at high dose enhancement CT. The finding of change in pancreatic contour and/or abnormal attenuation in a tumor could be detected in 47 cases at plain CT, 66 at early enhancement CT and 65 at high dose enhancement CT. Since the four cases in which neither finding was detected by any CT method showed dilatated main pancreatic duct, there was no case without abnormal CT finding. This combined CT method will be a reliable diagnostic technique in the imaging of pancreatic carcinoma.

Adult↗
PubMed1995

[Use of inferior epigastric artery for coronary artery bypass grafting].

The usefulness of the free inferior epigastric artery (IEA) as a coronary bypass graft was studied. Among 149 patients for coronary bypass grafting (CABG) between October 1992 and December 1994, the free IEA was used in 12 patients. The mean number of distal anastomosis was 3.7 per patient. The mean distal size of the IEA was 1.3 mm in diameter and the mean length was 9.4 cm. The IEA graft was anastomosed to the obtuse marginal branch in 5, to the diagonal branch in 4, and the right ventricular branch in 3. The proximal anastomosis of the IEA was constructed to the ascending aorta in three and to the saphenous vein (SVG) or to the internal thoracic artery (ITA) in 4 or 5, respectively. Postoperative angiogram demonstrated patent graft in ten and occluded graft in two in whom the size of IEA was less than 1.0 mm in distal diameter and the IEA was anastomosed to the aorta or to the SVG. The IEA was considered to be useful alternative arterial graft when it was used as "interposed graft" of which proximal anastomosis was made to the ITA and size-matching of the graft to the coronary artery was appropriate. The long-term patency of the graft can determine the true efficacy of the IEA for CABG.

Aged↗
PubMed1995

Long-term results after conservative aortic valve repair for aortic regurgitation with ventricular septal defect.

Aortic valve repair was performed in 61 patients having aortic regurgitation (AR) associated with ventricular septal defect (VSD). Preoperative regurgitation was classified according to the Sellers' classification and grade I was in 3 patients, grade II in 19, grade III in 34, and grade IV in 5 patients. Forty-six patients underwent only plication of aortic valve, and in 15 patients the commissuroplasty was added to reinforce the free edge of the cusp. Furthermore, aortoplasty (aortic annuloplasty) was performed in 11. Actuarial survival rate and freedom from reoperation rate were 91.6% and 87.2%, respectively at 10 years after the initial repair. The rate of freedom from deterioration for 22 patients showing grade I or II of AR before the initial operation was 86.4% at 1 year, 76.7% at 5 and 10 years, while the rate for 36 patients with grade III or more severe AR was 91.7% at 1 year, 77.4% at 5 years and 63.9% at 10 years. The rate at 10 years after operation between the two groups was different significantly (p < 0.05). Twenty among 22 patients having grade I or II of AR before operation were in NYHA class I, while 23 of 30 survivors with grade III or IV of AR were in class I, 6 in class II, and 1 in class III. Eight patients received reoperation and four of them underwent repeated conservative aortic valve repair, and one received aortic valve replacement at reoperation. Five of 7 survivors with reoperation improved in NYHA class I and 2 in class II. These results suggested that careful follow-up was required especially for the first 10 years after the initial operation in patients showing preoperative severe AR and receiving aortic repair.

Adolescent↗
PubMed1994

Limited effectiveness of FK506 administration for ongoing rejection in heterotopic rat heart transplantation.

A comparison was made of the histological findings for myocardial tissue of heterotopic transplanted rat hearts administered with FK506. ACI rats were used as donors and Lewis rats as recipients. FK506 was used for 6 days except for group I (control group). Group II received 0.32 mg/kg/day of FK506 from the day of operation while group III was given the same dosage from the 4th day after transplantation. Group IV was given 1.28 mg/kg/day of the agent from the day of grafting and group V received the same dose from the 4th postoperative day. The graft survival time was longer for all groups given FK506, but was significantly longer only for groups administered with FK506 from the day of operation. Histological studies performed 10 and 20 days after transplantation showed that a moderate rejection was seen in about half of the grafts receiving FK506 from the 4th day after grafting. An ultrastructural study of these cases showed that infiltrating large lymphocytes still remained in the interstitial tissues and that the cytoplasmic organelles of the myocytes had been focally destroyed. These results suggest that, although FK506 suppressed any further rejection, the effect might be limited and the myocardial changes of the cardiac graft might persist even after administration for ongoing rejection.

Animals↗
PubMed1994

Correlation between serum levels of alanine aminotransferase and ferritin in male blood donors with antibody to hepatitis C virus.

Chronic hepatitis C has been demonstrated to be associated with hepatic iron overload, and the hypothesis that the disease activity of hepatitis C is associated with iron cytotoxicity was tested in male volunteer blood donors. Sera with either antibody to hepatitis C virus or hepatitis B surface antigen were selected for determination of ferritin concentration and alanine aminotransferase activity. A correlation between serum ferritin concentration (Y; microgram/l) and alanine aminotransferase activity (X; IU/l) was found in donors with antibody to hepatitis C (log Y = 0.65 x log X + 0.98, r = 0.53, and P < 0.01). The correlation was lower in donors with hepatitis B surface antigen (r = 0.37; P < 0.01). Hepatitis C virus infection probably induces time-dependent iron accumulation associated with the progression of disease activity, while hepatitis B virus infection results in a variety of iron loads with different clinical features. The high disease activity related to hyperferritinemia suggests the presence of iron-induced liver damage in donors with hepatitis C.

Adult↗
PubMed1994

The St. Jude medical prosthesis in the mitral position.

To study the long-term results of the St. Jude medical prosthesis in the mitral position, 520 patients were evaluated who had undergone mitral valve replacement with St. Jude medical (SJM) prosthesis. Eighteen patients or 3.5% died in the early postoperative period (within 30 days after operation). The total follow-up was 2872 patient-years and late deaths occurred in 23 cases. Postoperative cerebral embolism occurred in six, bleeding complication in five, and thrombosed valve in two patients. Postoperative anti-coagulant therapy was initiated with both dipyridamole (300 mg/day) and warfarin potassium. After discharge from our hospital the patients underwent routine examination of their thrombo-tests or prothrombin times at least every 2-3 months, and the major thromboembolic or bleeding complication rate was 0.45%/100 patient-years. In a period of 12 years, severe hemolysis following implantation was seen in seven patients. The cause of this hemolysis was perivalvular leakage in two patients but there were no leakages in the other five patients, although preoperative moderate to severe liver dysfunction was noted. Ninety-three percent of the patients were followed up, and their postoperative New York Heart Association functional classes were I or II in 88.6% of the cases. Their clinical results after mitral valve replacement with SJM prosthesis in the anti-anatomical position showed excellent durability and a low incidence of valve-related complications.

Adolescent↗
PubMed1994

Coronary artery bypass grafting in elderly patients.

To determine the benefits of coronary artery bypass grafting (CABG) in elderly patients, we evaluated 37 patients more than 70 years old who underwent this surgical procedure and compared the results with those in 177 younger patients. Three-vessel lesions and left main lesion were seen in 78.4% and 48.6% of the elderly patients, respectively. Emergency or urgent surgery was performed on 19 patients and the number of distal anastomoses was 3.0 +/- 0.8 per patient. Left main lesion and emergency surgery were more common in elderly patients than in younger patients. Twelve patients received CABG with only a saphenous vein graft (SVG), while the remaining 25 patients had at least one arterial graft. The quality of the saphenous vein was poor to moderate in 50% of the elderly patients, while none of the arterial grafts showed significant sclerotic change. In 17 elderly patients, the ascending aorta showed sclerotic lesions and care was taken when completing proximal anastomoses of SVG to the aortic wall. After surgery, mechanical ventilation was required for an average of 29 h, which was longer than that in the younger patients. Postoperative low cardiac output, hypertension, and arrhythmia occurred in 6, 6 and 15 elderly patients, respectively. There were no early deaths, although there was one hospital death due to posttransfusion hepatitis. Thirty four elderly patients were classified as New York Heart Association functional class I or II during late follow-up maximum of 5 years) and only one had postoperative angina. The ascending aorta showed more sclerotic lesions, and the quality of the saphenous vein was worse, in the elderly patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Cardiac lipoma with changes of ST segment and T wave on electrocardiogram.

We report a case of cardiac lipoma found by chance as a cause of ST-T changes which suggested left ventricular hypertrophy. A 38-year-old man was completely asymptomatic and was incidentally found to have an abnormal electrocardiogram during a regular physical examination. Echocardiography revealed an oval mass located in the inferior wall of the left ventricle near the apex, and there was no finding of left ventricular hypertrophy. Computed tomography and magnetic resonance imaging, rather than echocardiography, were useful in determining the characteristics of the lipoma in this case. The tumor was resected by operation and the histology showed lipoma with no evidence of malignancy.

Adult↗
PubMed1994

[Surgical treatment for postinfarction ventricular septal perforation].

Between August 1981 and August 1992, operation for ventricular septal perforation (VSP) after acute myocardial infarction (AMI) was performed in 12 patients and the results were studied. During this period, medical treatment was attempted as a standard therapy for more than two weeks after AMI, followed by operation. However, only four patients received elective operation two weeks after the onset of AMI. Regarding the relationship between the preoperative circulatory status and timing of surgery, elective operative could not be performed in seven patients showing a pulmonary to systemic flow ratio (Qp/Qs) of more than 3.0, while four out of five patients with a ratio of less than 3.0 received operation more than two weeks after the onset of AMI. Two patients with severe right heart failure after the repair of VSP died on table without weaning from the pump. Ten operative survivors were weaned from the pump without any difficulty of hemostasis and intraaortic balloon pumping was removed after operation. However, three patients died of multiple organ failure which had been deteriorating before operation. Postoperative activity improved to New York Heart Association Functional Class I or II in six survivors for the late follow-up period. In the case of high Qp/Qs due to VSP, early operation is recommended to prevent multiple organ failure.

Aged↗
PubMed1994

Improvement of serum aminotransferase levels after phlebotomy in patients with chronic active hepatitis C and excess hepatic iron.

OBJECTIVES: Iron metabolism may be altered in patients with chronic active hepatitis C. In an attempt to evaluate whether excess iron contributes to liver injury, we used phlebotomy for removal of iron from patients with chronic hepatitis C. METHODS: All 10 patients had histochemically detectable iron in the liver and underwent an initial period of weekly or monthly phlebotomy of 200 or 400 ml. A serum ferritin level of 10 ng/ml or less was chosen as the endpoint, and maintenance phlebotomy was performed if the level rebounded. RESULTS: The treatment reduced mean serum alanine aminotransferase activity from 152 +/- 49 to 55 +/- 32 IU/L; this level became normal in five of the 10 patients. Anti-HCV antibodies could be detected in all patients throughout the study. Histologic abnormalities of the liver were unchanged except for disappearance of iron deposits from seven of the patients studied. CONCLUSIONS: Our findings suggest that iron removal may be beneficial for patients with chronic active hepatitis C and histochemical iron in the liver.

Adult↗
PubMed1994

Ruptured aneurysms of the sinus of Valsalva.

Sixteen patients underwent operation for ruptured aneurysm of the sinus of Valsalva (RASV) between 1979 and 1992. The age ranged from nine to 57 years (mean 31.8 years). Four patients were asymptomatic and 12 symptomatic and among symptomatic patients, five patients underwent emergency operation. Associated congenital anomalies were subpulmonary ventricular septal defect in 11 patients and infundibular pulmonary stenosis in one patient. Aortic regurgitation (AR) was mild in four, moderate in two, and severe in five. Surgical approach for RASV was a double incision for 12 patients (incision of ascending aorta and pulmonary artery, seven; that of ascending aorta and right ventricle, five), and single incision in four (pulmonary artery, three; right ventricle, one). Concomitant aortic surgery was performed in seven patients: aortic valve replacement (AVR), six and aortic valvuloplasty, one. One patient with emergency operation after cardiac arrest died one day after operation, while four emergency and 11 elective patients were uneventful after operation. In a follow up period of a mean of 90.3 months, there were no leaks of VSD closure and no recurrence of aneurysm. In 10 patients without AVR, mild AR remained in two, while the others showed no AR. The New York Heart Association functional class after operation was class I for 14 and class II for one. It seems that RASV requires early examination and operation to prevent an acute deterioration of symptoms and AR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Emergency coronary artery bypass grafting with warm blood cardioplegia for a patient with acute myocardial infarction and severe left ventricular dysfunction].

Emergency coronary artery bypass grafting was performed in a 61 year old man who developed acute severe cardiac and respiratory dysfunction after myocardial infarction. At operation cardiac arrest was obtained by warm blood cardioplegia in antegrade intermittent fashion. The left anterior descending artery, diagonal branch, and right coronary artery were revascularized by saphenous vein (SVG). After declamping the aorta, spontaneous heart beating was obtained and postoperative course was uneventful. Postoperative examination showed patent all SVGs and improved cardiac function. Although the delivery of the warm blood cardioplegia was controversial, our recent study revealed that the intermittent antegrade delivery of warm blood cardioplegia showed no ischemic changes of the heart during the procedure.

Coronary Artery Bypass↗