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Biomedical subjects

R Sakata

Publications and source records attributed to R Sakata.

At least 73 records · Page 4Linked to original sources
PubMed1999

Coronary artery bypass grafting in dialysis patients.

BACKGROUND: To analyze the characteristic problems of coronary artery bypass grafting in patients with chronic renal failure. METHODS: Fifty-one consecutive dialysis patients who required isolated coronary bypass grafting over a 9-year period were studied retrospectively. RESULTS: Nine patients (18%) had emergent operation, 4 of whom had intraaortic balloon counterpulsation instituted preoperatively. A mean of 3.3 +/- 1.0 bypasses per patient were grafted; 14 patients (27%) had bypass with two arterial grafts, 13 (25%) of which used left internal mammary artery and gastroepiploic artery and one of which used bilateral internal mammary artery grafts. A mean of 4.2 +/- 2.6 coronary artery segments were calcific according to American Heart Association classification. Eight patients (16%) required operative modifications to avoid manipulating calcific plaques on the ascending aorta. Four patients (7.8%) died, and 15 had nonlethal complications. The actuarial survival rates in 47 hospital survivors at 1, 3, and 5 years were overall 89%, 84%, and 71%, respectively, and estimates for cardiac deaths 93%, 93%, and 82%, respectively. Cardiac event-free rates after coronary artery bypass grafting were 83% and 65% for 3- and 5-year periods, respectively. CONCLUSIONS: Calcification of coronary arteries and the ascending aorta is a serious problem in long-term dialysis patients. However using arterial grafts, preferentially, in situ, seems to provide a practical alternative to minimize manipulating the ascending aorta during coronary artery bypass grafting, with acceptable perioperative morbidity and mortality rates and long-term survival.

Adult↗
PubMed1999

Coronary artery bypass grafting in patients with systemic lupus erythematosus.

OBJECTIVE: Few reports exist on the results of coronary artery bypass grafting (CABG) in patients with systemic lupus erythematosus (SLE). METHODS: We retrospectively reviewed eight CABG in seven SLE patients. In early and late postoperative angiography, all grafts were evaluated for occlusion, development of string sign, or presence of significant stenosis. The early and late results were compared. The pathological studies were performed on the segments of the internal thoracic artery (ITA) and saphenous vein collected from each patient. Atherosclerosis of the ITA was analyzed using the subjective evaluation proposed by Kay et al. (Kay HR, Korns ME, Flemma RJ, Tector AJ, Lepley D. Atherosclerosis of the internal mammary artery. Ann Thorac Surg 21;1976:504-507) scale 0-4 (0 = normal, 1 = minimal disease, 2 = less than 25% luminal narrowing, 3 = 25-50% narrowing, and 4 = greater than 50% narrowing). RESULTS: The patients consisted of three men and four women with a mean age of 59.8 years. Co-morbid diseases were frequent and there were three patients (37.5%) with renal failure (two dialysis patients, one with renal dysfunction) and two patients with severe atherosclerosis of the aorta. The ITA was used in four patients. Saphenous vein graft was used in seven patients. Concomitant procedures included aortic valve replacement and mitral annuloplasty, mitral valvuloplasty and tricuspid annuloplasty, mitral valve replacement and tricuspid annuloplasty (TAP). There was one hospital death (12.5%). Early patency rates were 87.5% (21/24). No other atherosclerotic changes or stenosis suggesting vasculitis were noted. In pathological studies, there was no significant atherosclerosis in the six ITA specimens from four patients, although three patients had degree two atherosclerosis. No vasculitis was found in ITA or saphenous vein grafts. During the mean follow-up period of 35.3 months (range, 5-91 months), there was one non-cardiac late death. Late restudy (in three patients, 12, 57 and 64 months later respectively) revealed no deterioration in either ITA or vein grafts. Overall prognosis after the operation in SLE patients appears to be good. No other cardiac events were observed, and patients demonstrated marked clinical improvement. CONCLUSIONS: CABG in SLE patients can be performed with acceptable morbidity and mortality. Our data so far reveals no evidence to preclude the use of ITA and vein grafts in SLE patients.

Adult↗
PubMed1999

[Evaluation of the results of the combined maze procedure for chronic atrial fibrillation with organic heart disease].

To examine the surgical indications and the results of the maze procedure, we reviewed 30 cases who underwent the maze procedure concomitantly with other open heart surgery from October 1995 to October 1997.: the average age was 60.9 years (37 to 75 years) and mean follow up period was 12.3 months (1 to 25 months). The modified maze procedure described by Kosakai and associates was applied in all patients. Twenty one patients (72.4%) regained atrial rhythm and eight patients (27.6%) sustained atrial fibrillation in the follow up periods. The left atrial diameter measured by echocardiography and cardiothoracic ratio were significantly larger in the latter group of patients, compared with those who recovered normal sinus rhythm (63.8 +/- 19.5 versus 51.2 +/- 7.8 mm and 67.7 +/- 8.1 versus 59.2 +/- 5.4%). In order to perform the combined maze procedure, cardiac arrest time and cardiopulmonary bypass time were extended for 56.9 minutes and 65.9 minutes, respectively, compared with the cases without a maze procedure. Four patients (brady atrial fibrillation 2, brady junctional rhythm 1, and complete AV block 1) required permanent pacemaker implantation. There was no operative death, but one patient who underwent the maze procedure and AVR + MAP + TAP died after 4 months due to pulmonary infection, sepsis and multiple organ dysfunction. This patient had shown low output syndrome for 3 days postoperatively. Having considered the data that the preoperative ejection fraction was 51%, cardiopulmonary bypass and cardiac arrest time were 200 min and 165 min respectively, occurrence of low cardiac output had been influenced by prolonged aortic cross-clamp. No late deaths have been observed in follow up period. In conclusion, maze procedure should not be performed in patients who have enlarged left atrium or complex cases requiring relatively longer operative time.

Adult↗
PubMed1998

Long-term patency rate of right internal thoracic artery bypass via the transverse sinus.

BACKGROUND: Although concern regarding patency and possible compromise of graft blood flow by routing the right internal thoracic artery (RITA) through the transverse sinus has been raised, little is known about long-term patency. METHODS AND RESULTS: To evaluate long-term patency of in situ RITA bypass via the transverse sinus, our first 115 patients (94 men, 21 women; mean age, 62.5 years; range, 13 to 77 years) who were alive in 1998 were enrolled for angiographic study. Only good-caliber grafts with no occlusion, string sign, or significant stenosis were considered patent. Early postoperative angiography had been performed 2 to 3 weeks after surgery in 114 patients. The early patency rates were 97.1% for RITA and 95.4% for left internal thoracic artery (LITA) grafts. Of 109 long-term survivors, 73 (67.0%) consented to have late angiographic restudy at a mean of 59 months (range, 9 to 93 months); 89.9% of RITA and 92.3% of LITA grafts were patent. Cumulative patency rates (actuarial curves) at 6 years were 89.3% (95% CI, 85% to 94%) for RITA and 94.5% (95% CI, 92% to 97%) for LITA, the differences not reaching statistical significance (multivariate Cox analysis). CONCLUSIONS: Our study demonstrated good long-term patency of in situ RITA bypass grafting via the transverse sinus for revascularization of the circumflex and diagonal arteries and supports its continued use.

Adolescent↗
PubMed1998

[The propriety of bilateral internal thoracic artery grafting in women].

In our institution, the exclusion criteria of the bilateral internal thoracic artery (BITA) grafting include age over 70 years old, obesity, severe diabetes, renal dysfunction and poor preoperative physical activity. The objective of this study is to evaluate propriety of the use of bilateral internal thoracic artery for coronary artery bypass grafting (CABG) in women. Clinical outcome of female patients who underwent BITA grafting (group B-F; n = 50) was compared with that of female patients who underwent single internal thoracic artery grafting (group S; n = 50). In addition, clinical outcome of the male patients who underwent BITA grafting (group B-M; n = 50) was compared with that of group B-F. Between group B-F and S, the age, prevalence of obesity and that of renal dysfunction were significantly different, which was predictable because of the group selection according to the criteria. However, the prevalence of previous myocardial infarction and that of left ventricular dysfunction and the extent of coronary artery disease were not significantly different. Whereas, between group B-F and B-M, preoperative factors were not significantly different except the body size. Intraoperative technical factors, such no of grafts, aortic cross clamp time, cardiopulmonary bypass time, rate of complete revascularization, were not significantly different. In comparison of group B-F with group B-M, the site of anastomosis with arterial grafts were not significantly different. Patency rate of arterial and venous grafts two week after operation was not significantly different. Either postoperative complications, such as reoperation for bleeding, wound complication, low output syndrome, renal dysfunction etc, were not significantly different. One patient (2%) in group B-F and 1 patient (2%) in group B-M died in the hospital (p > 0.05). In summary, BITA can be a viable conduit of choice for CABG in female patients as well as that in male patients. Criteria of the use of BITA is recommended to exclude preoperative risk factors above-mentioned.

Aged↗
PubMed1998

[Mitral valve regurgitation with anterior mitral leaflet chordal rupture or elongation--repair using the flip-over technique].

Repair of prolapsed anterior mitral leaflet has remained technically difficult. The purpose of this study was to assess the clinical results after using the flip-over technique for patients with anterior mitral leaflet prolapse due to dhordal rupture or elongation. Between January 1993 and September 1997, fifteen adult patients with pure mitral valve regurgitation (MR) due to prolapse of the anterior mitral leaflet underwent repair using the flip-over technique. The indication for this procedure were; 1) all mitral structures except the prolapsed area must appear to be intact, and 2) the corresponding chordae attached to the posterior leaflet should be sufficiently strong to be transferred to the anterior leaflet. The prognoses following this technique were retrospectively studied to assess the early and mid-term clinical outcome of this procedure. Follow up was complete in all patients and ranged from 2 to 56 months (with a mean of 25 +/- 17.9 months). There was no hospital death, None required reoperation. One patient died because of acute recurrent MR during follow-up. No other complication was experienced. Doppler echocardiographic studies at the final follow-up showed less than mild regurgitation in 11 (78.6%) of the 14 surviving patients. We believe that this procedure was effective for that the obtained repair of a prolapsed anterior mitral valve and early and mid-term clinical outcome from this procedure has been satisfactory.

Adult↗
PubMed1998

[An evaluation of cases carried out by both root reconstruction using Carrel patch method and concomitant procedure].

During the past 7 years from January 1991 to November 1997, we experienced 31 cases of aortic root reconstruction utilizing Carrel patch method. Concomitant procedure were performed in 9 cases of them due to another cardiovascular disease. Complicated cardiovascular disease included 3 cases of ischemic heart disease, 3 cases mitral regurgitation and one case of Aortic arch aneurysm. Several concomitant procedures were performed; 5 cases of CABG, 2 cases of mitral annuloplasty, one case of CABG with mitral valve replacement and one case of aortic arch replacement. The mean extra corporeal circulation time was 190.6 +/- 39.3 minutes and aortic clamp time was 147.8 +/- 34.2 minutes in these 9 cases. There were no significant differences of operative results between the simple root reconstruction group and the concomitant procedure group. We concluded that the aortic root reconstruction using the Carrel patch method has few complications. Although further long-term follow-up is required, our experiences suggest that the aortic root reconstruction with the concomitant procedure can be carry out safely with the aid of appropriate assistance method.

Adult↗
PubMed1998

[Separate operation for extensive aneurysm (mega-aorta) complicated with ischemic heart disease].

A seventy one year-old woman, who had an arch and thoracoabdominal aortic aneurysm (type II according to Crawford classification) with ischemic heart disease, underwent a separate operation using the elephant trunk method. At first, she underwent the ascending aorta and arch replacement the with elephant trunk technique, and, underwent CABG simulutaneously utilizing the separate extra corporeal circulation and hypothermic circulatory arrest. The Chest and abdominal CT revealed the enlargement of abdominal aortic aneurysm 5 months after operation. The second operation was performed using Stoney's spiral opening method and the revasculization of spinal arteries (Th6, 7 and Th9) underwent the segmental aortic clamping to prevent spinal cord ischemia. Furthermore, the second operation was performed using selective perfusion to visceral arteries and F-F bypass for the prevention of visceral ischemia. Each flow rate by selective perfusion in major abdominal blanches was from 50 to 100 ml/min. Therefore, hepatorenal dysfunction and paraparesis did not occur after the second operation. It was suggested that the segmental aortic clamping and the selective perfusion to visceral arteries with F-F bypass may be effective to prevent the ischemia of the spinal cord and abdominal organs.

Aged↗
PubMed1998

A case-control study on male hepatocellular carcinoma based on hospital and community controls.

A case control study on male primary hepatocellular carcinoma(HCC) and hepatitis B or C virus and some potential risk factors, e.g. blood transfusion, aldehyde dehydrogenase 2(ALDH2) genotype and drinking habits, was performed using two controls, i.e. a hospital control(HC) and a community control(CC) in Fukuoka and Saga Prefectures. Cases were obtained from the Second Department of Internal Medicine, Kurume University Hospital. The HCs were obtained from inpatients of two general hospitals in Kurume and the CCs were randomly sampled from the Kurume citizens being matched with age and sex to each case. Based on the HCs, odds ratios(ORs) of developing male HCC were statistically significant due to HBsAg or anti-HCV antibody positive status. Some discrepancies were observed between the two controls, i.e. higher proportions of past histories of diabetes or hypertension, of ALDH2 typical homozygote(ALDH2(1)/ALDH2(1)), and of heavy drinkers among the HCs, suggesting slight deviation of the HCs from the CCs in alcohol related aspects. Although ORs regarding accumulated amount of alcohol intake by age 40 based on the HCs were insignificant, two of the three corresponding ORs based on the CCs were statistically significant. Judging from alcohol related aspects between the two controls, the ORs for alcohol based on the HCs seems to be underestimated.

Adult↗
PubMed1997

Hepatic stellate cells and intralobular innervation in human liver cirrhosis.

In normal and cirrhotic human liver tissues, we examined immunolocalization of alpha-smooth muscle actin (alpha-SMA), endothelin-1 receptor (ET-1R), and S-100 protein, with special emphasis on the intralobular spaces, using immunohistochemical methods. The ratio of the number of hepatic stellate cells (HSCs) with closely apposing nerve endings to the total number of HSCs in normal livers was compared with that in cirrhotic livers by electron microscopy. Immunolocalization of alpha-SMA and ET-1R was obviously recognized along the sinusoidal walls in cirrhotic liver and was significantly increased in cirrhotic liver compared with that in normal liver. Immunoreactive products for these substances were mainly localized in HSCs. However, immunolocalization of S-100 protein in intralobular spaces was markedly decreased in cirrhotic liver compared with that in normal liver. Nerve fibers were ultrastructurally hardly visible in intralobular spaces of cirrhotic livers. The ratio of the number of HSCs with closely apposing nerve endings to the total number of HSCs was significantly reduced in cirrhotic liver compared with that in normal liver. These results indicate that in liver cirrhosis, alpha-SMA-positive HSCs may play an important role in hepatic sinusoidal microcirculation through vasoactive agents such as ET-1 rather than through intralobular innervation.

Actins↗
PubMed1997

Formation of black pigment gallstone in a hamster model of experimental cirrhosis.

The relationship between liver cirrhosis and the pathogenesis of black pigment stones has not been clarified. We attempted to induce black pigment stone formation in the gallbladders of hamsters. Male golden hamsters were divided into a cirrhosis group and a control group. Liver cirrhosis was induced by administering drinking water containing thioacetamide. The control group was given tap water. Gallstones at 48 weeks after treatment were examined by stereoscopic microscopy and scanning electron microscopy. The copper content of the black pigment stones was analysed by atomic absorption spectrophotometry. Black pigment stones in the gallbladder were detected in 25% of the cirrhosis group. Their surface and cross-section appeared amorphous. Black pigment stones contained copper. We confirmed the formation of gallstones in an animal model of cirrhosis by thioacetamide. Our findings may contribute to the clarification of the relationship between the pathogenesis of black pigment stones and the pathophysiology of liver cirrhosis.

Animals↗
PubMed1997

Cerebral ischemic disorders and cerebral oxygen balance during cardiopulmonary bypass surgery: preoperative evaluation using magnetic resonance imaging and angiography.

We compared the preoperative prevalence of small cerebral infarctions and carotid stenosis to jugular venous oxygen saturation (Sjvo2) during coronary artery bypass grafting (CABG). Sjvo2 served as an indicator of whether cerebral oxygen supply meets demand in patients on cardiopulmonary bypass (CPB). The study population consisted of 121 patients who were either older than 65 yr or had a history of cerebrovascular disease. The patients underwent preoperative cerebral magnetic resonance imaging (MRI) and cervical magnetic resonance angiography (MRA) to detect small cerebral infarctions and carotid artery stenosis. Patients with atherosclerosis of the ascending aorta were identified by intraoperative epiaortic ultrasonography. Liberation of emboli from the aorta in these patients was prevented by modification of the standard operation. From preoperative MRI and MRA, 65 patients (54%) had small cerebral infarctions in the white matter or basal ganglia and nine patients (7%) demonstrated moderate or severe stenosis in the carotid arteries. Thirteen patients (11%) had moderate or severe atheromatous disease of the ascending aorta. The severity of aortic atherosclerosis was significantly correlated with the grade of carotid stenosis (P < 0.05). In patients with small infarctions, Sjvo2 was significantly lower than in patients without infarctions (controls) at initiation of CPB, 30 min after aortic cross-clamping, and during the rewarming period of CPB (P < 0.05). Thus, small cerebral infarctions were not uncommon in elderly patients undergoing CABG. Patients with small cerebral infarctions may be at risk for an imbalance in cerebral oxygen supply and demand during the rewarming period because they are unable to deliver the necessary compensatory blood flow.

Aged↗
PubMed1997

Synthesis of nitric oxide from the two equivalent guanidino nitrogens of L-arginine by Lactobacillus fermentum.

Ten strains of Lactobacillus fermentum that differed in origin converted metmyoglobin to nitrosylmyoglobin [a pentacoordinate nitric oxide (NO) complex of Fe(II) myoglobin] in MRS broth at pH 4.3. Of the 10 strains, L. fermentum IFO 3956 possessed the strongest capacity to convert metmyoglobin to nitrosylmyoglobin. This strain synthesizes NO enzymatically from the two equivalent guanidino nitrogens of L-arginine. To our knowledge, this demonstrates for the first time the production of NO synthesized from the guanidino nitrogens of L-arginine by lactic acid bacteria. IFO 3956 may possess a bacterial NO synthase.

Arginine↗
PubMed1997

Reduced contractility and histological changes in the gallbladder due to portal hypertension in a hamster cirrhosis model.

BACKGROUND/AIMS: Little is known about the relationship of portal venous pressure to contractility and histological changes in the gallbladder. In this study, we investigated the relationship between portal hypertension and contractility and histological changes in the gallbladder in a hamster cirrhosis model. METHODS: Liver cirrhosis was induced in the hamsters (n = 20) by thioacetamide (TAA). Portal venous pressure was directly measured using a pressure-measuring instrument. The contractility of the gallbladder was appraised by the diameter before and after caerulein treatment. Gallbladder wall thickness and vessel areas in tissues were evaluated in relation to the portal venous pressure. RESULTS: The portal venous pressure, gallbladder wall thickness with submucosal edema and area of vessels in the gallbladder wall in the cirrhosis group were significantly increased compared with those in the control group (n = 20, receiving saline instead of TAA). The gallbladder contraction rate in the cirrhosis group was significantly decreased compared with that in the control group. In the cirrhosis group, there were positive correlations between the portal venous pressure and the gallbladder contraction rate, gallbladder wall thickness, and area of vessels. CONCLUSIONS: In the gallbladders of experimental cirrhotic hamsters, portal hypertension caused dilatation of the vessels as well as submucosal edema, and was an important factor in the increased thickness and reduced contractility of the gallbladder wall.

Animals↗
PubMed1997

The significance of colocalization of plasminogen activator inhibitor-1 and vitronectin in hepatic fibrosis.

BACKGROUND: We examined the relationships among vitronectin (VN), plasminogen activator inhibitor-1 (PAI-1), and transforming growth factor beta 1 (TGF-beta 1) in liver diseases to evaluate the presence of plasmin cascade in human hepatic fibrosis. METHODS: Blood and liver tissues were obtained from 57 patients with liver disease. Plasma VN, PAI-1 antigen, and PAI-1 activity levels were evaluated. Biopsied liver specimens were observed by light and electron microscopy after immunohistochemical staining. Morphometric analysis was performed on these specimens. RESULTS: Plasma VN and PAI-1 activity levels decreased significantly with the progression of hepatic fibrosis and were particularly marked in the liver cirrhosis group. Plasma PAI-1 antigen level increased significantly. The immunolocalization of the active form of TGF-beta became more intense with the progression of hepatic fibrosis, whereas that of the dual-stained positive areas of PAI-1 and VN (PAI-1.VN) decreased. There was a positive correlation between TGF-beta and PAI-1, whereas there was a negative correlation between TGF-beta and PAI-1.VN. Immunoelectron microscopy showed the localization of PAI-1-VN in the extracellular space around the sinusoidal cells or surface of aggregating platelets, TGF-beta mainly in Ito cells, and VN in hepatocytes near the focal necrotic area or fibrous septa. CONCLUSIONS: These findings suggest that VN and PAI-1 are related to the active form of TGF-beta and that it is possible that the plasmin cascade is present in the human liver.

Adult↗
PubMed1997

[Traumatic transection of the descending thoracic aorta with free open rupture in left pleural cavity--a case report].

A 33-year-old male was admitted to our hospital because of mediastinal bleeding by the traffic accident. He was in shock state. Chest roentgenogram showed widening of the upper mediastium, massive pleural effusion and deviation trachea to right. Chest CT scan showed left hemothorax and deviated mediastinum to right. Immediately after the end of the CT scan, the pulse of bilateral femoral artery was not palpable. Therefore, we started cardiac massage and carried to the operation room in a hurry. Under cardiac massage, median sternotomy was made. But, there were no abnormal findings in the ascending aorta and arch. Under ECC, left anterolateral incision was added. We found that the transection of the descending thoracic aorta was transversely without preservation of the adventitia and it reached a round of the aorta. Five cm of the descending aorta from just distal to the left subclavian artery was replaced with 22 mm Hemashield graft under the separate perfusion of upper and lower body and circulatory arrest. Postoperative course was stable and the patient was healthy at present.

Accidents, Traffic↗
PubMed1997

[Coronary artery bypass surgery in patients over 75 years].

Coronary artery bypass graft surgery is increasingly common in patients over 75 years. In our institution, a consecutive series of 936 patients undergoing isolated CABG between May 1988 and July 1996 included 154 patients older than 75 years. These elderly patients were divided into two group (group A: 40 patients over 80 years old, group B: 114 patients younger than 80 years) and the patients in group A and group B were compared with 100 consecutive patients younger than 75 years who underwent CABG in 1996 (group C). Mean age for elderly patients was 78.1 and for group C patients 64.2 years. Emergency operation and preoperative use of IABP were significantly frequent in group A (p < 0.05). Left main trunk stenosis was more frequent in group A patients (p < 0.05), while the number of diseased vessels did not differ. Mean number of grafts and arterial grafts were higher for group C patients. The frequency of use of arterial grafts in elective cases were lower for group A and group B patients. (p < 0.05, 86.3% group A, 91.3% group B, 100% group C). Although the frequency of mediastinitis and long stay of ICU (over 5 days) were significantly higher in group A (p < 0.05) and older patients tended to have higher postoperative morbidity, the hospital mortality did not differ between the groups (5.0% group A, 4.4% group B, 1.0% group C). We conclude that CABG in patients over 75 years of age can be performed with acceptable mortality. Patients should not be denied CABG because of age alone.

Adult↗