Biomedical subjects

R Sakata

Publications and source records attributed to R Sakata.

At least 91 records · Page 5Linked to original sources

PubMed1997

[Cardiac surgery in patients with chronic renal failure on maintenance dialysis].

From July 1988 through August 1996, 54 patients with chronic renal failure (CRF) on maintenance dialysis (50 hemodialysis = HD, and 4 continuous ambulatory peritoneal dialysis) have undergone some sort of surgical procedure requiring the use of extra corporeal circulation (ECC); 42 patients underwent isolated coronary artery bypass grafting (CABG), 8 valve replacement, 3 combined procedures and 1 correction of a congenital heart defect. The protocol called for maintenance dialysis on the day before surgery, large volume hemofiltration (HF) during the ECC period, postoperative K+ management with dextrose-insulin if required, and resumption of whatever preoperative maintenance dialysis 24 hours after the operative procedure. The mean diafiltrate volume of HF was 7963 +/- 2688 ml which was replaced with 6342 +/- 2748 ml. No patient required emergency HD before the resumption of the maintenance dialysis, although in 40% of the early patients HD was added on the second postoperative day. However as experience was gained, in the latter 60% of patients resumption of maintenance dialysis (HD 3 times a week) was thought to be sufficient. The incidence of calcification in patients with CRF is higher not only of involved coronary artery segments (4.5 +/- 2.3 segments; AHA coronary classification) than its counterpart without CRF, but also of the ascending aorta which mandated modifications of the technique in 6 patients (operation under ventricular fibrillation, cannulation access other than ascending aorta). The use of arterial in situ conduits for CABG was also thought to be advantageous, and the left internal thoracic artery combined to the gastro-epiploic artery was used in 11 patients (26.2%). Four patients died) (7.4%): 2 from arrhythmia, one from intestinal necrosis and one from multiple cerebral infarction. Thus we conclude that the outlined protocol is quite effective in controlling fluid and electrolyte balance in patients on maintenance dialysis allowing to undertake surgical procedures requiring the use of extra corporeal circulation relatively safely.

Adult↗

PubMed1996

Expression of angiotensin-converting enzyme in remaining viable myocytes of human ventricles after myocardial infarction.

BACKGROUND: Local ACE in the heart may be important in the pathophysiological state after myocardial infarction (MI). It is unknown, however, whether ACE is expressed in myocytes of the human heart. METHODS AND RESULTS: Using a newly generated polyclonal antibody to a synthetic peptide corresponding to part of the human endothelial ACE sequence, we examined the localization of ACE in left ventricles of patients (n = 10) with MI obtained at left ventricular aneurysmectomy or autopsy and in the hearts of control subjects at autopsy (n = 10). The avidinbiotinylated peroxidase complex method was used for the immunohistochemical staining for ACE. In the left ventricles, positively stained myocytes for ACE were found in 8 of the 10 patients with MI. ACE immunoreactivity was seen in the remaining viable myocytes located near the infarct scar of the aneurysmal left ventricle and in nonmyocytes such as fibroblasts, macrophages, vascular smooth muscle cells, and endothelial cells within the scarred tissue. On the other hand, no immunoreactivity for ACE was detected in the ventricular myocytes of all control hearts obtained at autopsy. CONCLUSIONS: We observe immunohistochemical staining for ACE in the left ventricular myocytes of the region adjacent to the infarct scar and in nonmyocytes. These results indicate that ACE is markedly increased on the edge of the infarct scar and suggest that local ACE may be important in the ventricular remodeling after MI.

Aged↗

PubMed1996

In situ right internal thoracic artery graft via transverse sinus for revascularization of posterolateral wall: early results in 116 cases.

The in situ right internal thoracic artery graft brought through the transverse sinus was used to revascularize the posterolateral wall in 116 patients. Its advantages were assessed retrospectively. The graft was anastomosed to the circumflex marginal branch in 70 patients (60%) or to the posterolateral branch in 41 patients (35%). One patient died (mortality rate 0.9%). Perioperative myocardial infarction occurred outside the territory of the right internal thoracic artery graft in 10 patients, four of whom required mechanical support for hemodynamic deterioration. Postoperative early angiography in 114 patients found the graft to be patent in 97.4%. The ratio of the diameter of the right internal thoracic artery to that of the recipient marginal branch was 0.94 +/- 0.18 (n = 69), and that to the posterolateral branch was 0.88 +/- 0.18 (n = 37) (not significantly different). Results of a postoperative stress test were abnormal in one patient (1/96 tested patients). This retrospective study suggests that the right internal thoracic artery brought through the transverse sinus to revascularize the posterolateral wall provided excellent early patency and good clinical results, even to the most distally located branches. This continues to be our procedure of choice for patients with multivessel coronary disease.

Adolescent↗

PubMed1996

Rapid analysis of small samples containing forskolin using monoclonal antibodies.

The effective range of the competitive ELISA test for detection of forskolin content in clonally propagated plant organs of Coleus forskohlii using monoclonal antibodies extends from 5ng to 5 micrograms. A correlation between the forskolin accumulation and the growth rate was investigated using the clonally propagated shoots. An increase of forskolin content was noted, beginning at week 6. Flowers, rachises, leaves, stems, tuberous roots, and roots were analyzed. Tuberous roots and the stem base contained higher amounts of forskolin than other organs. The forskolin content in the stem decreased gradually towards the top of the shoot.

Animals↗

PubMed1996

[Coronary artery bypass surgery in patients over 80 years].

Coronary artery bypass grafting (CABG) was being performed with increased frequency in elderly patients. However, the results of operations in patients over the age of 80 years have not been previously reported in Japan. Between May 1988 and September 1994, we have performed CABG in 28 patients over the 80 years of age (group A: mean 82.2). These patients were compared with 240 patients in 60s (group B: mean 65.0). Mean New York Association functional class (NYHA) was significantly higher in group A (p < 0.01). Left main trunk stenosis was more frequent in group A patients (p < 0.01), while the number of diseased vessels did not differ. Preoperative use of an intra-aortic balloon pump (29%) and emergency operation (54%) were more frequent in group A patients (p < 0.01). There was no significant difference in the number of grafts per patient between the groups (2.93 for group A versus 2.93 for group B), but the internal mammary artery was used more frequently in group B patients (99% versus 39%, p < 0.01). In group A, the major complicatines were stroke, cardiac tamponade, reoperatin for bleeding and respiratory failure in 1 patient each (3.6%). The hospital mortality did not differ between the groups (0% for group A and 2.9% for group B). In group A, at mean follow-up of 16.3 months, 25 patients (89%) are alive and no patient had recurrent angina. We conclude that CABG in patients over 80 years of age can be performed with low mortality and significant symptomatic benefit. Patients should not be denied CABG because of age alone.

Age Factors↗

PubMed1996

[An evaluation of aortic root reconstruction using Carrel patch method with coronary anastomosis].

During the past 4 years, from January 1991 to December 1994, we experienced 12 cases of aortic root reconstruction utilizing Carrel patch method. The cases included annulo-aortic ectasia (AAE), root aneurysm with aortic regurgitation (AR), and aortic dissection with AR. The aortic valve and aortic root were resected, the coronary ostia were dissected free, mobilized, and then implanted to the composite graft. Coronary anastmosis was performed by mattress suture and reinforced by Tefron felt strips. It was necessary in one case to undergo coronary artery bypass grafting for myocardial ischemia due to coronary ostial stenosis. Operative procedure could be performed in 4 cases without blood transfusion. Post operative death was seen in only 1 case at 25 postoperative day, who underwent on emergency operation for cardiac tamponade due to aortic dissection. Pseudoaneurysm formations of coronary ostia or hospital death was not observed in any other cases during follow up period (average 25 months). Late tamponade was shown in one case as a complication, and the majority of cases had uneventful postoperative course. The operative procedure is considered feasible in any anatomic variation of the aortic root disease, even if dislocation of coronary ostia is minimal, and can be expect for prevention of pseudoaneurysm formation, and long term survival.

Adult↗

PubMed1996

[Cerebral complication during open heart surgery in relation to cerebral arterial stenosis documented by angiography].

To determine the cause of a cerebral lesion after open heart surgery, a cranial 4-vessel-study was performed prior to an elective operation in 89 patients, who were over 70 years of age and/or had a previous history of cerebro-vascular diseases (CVD). Patients with arterial stenosis over 75% to complete obstruction were categorized as the significant stenosis group and the others as the normal findings group. Of the 89 cases, 19 (21.1%) showed significant stenosis, among which six patients were found to have complete occlusion of the internal carotid artery. Seven patients (7.9%) developed postoperative neurological complications, with four patients having single or plural significant stenosis. Angiograms of three of those four patients revealed complete obstruction of their internal carotid arteries. The stenotic group showed a tendency toward neurological complications in comparison with the non-stenotic group although the incidence was not significant (p = 0.054). However analysis of the group with complete occlusion of the internal carotid artery indicated significant increased risk for cerebral complication (p < 0.013). Besides the 89 patients studied, an additional 479 patients who had not undergone preoperative angiography were subjected to this study whether the patient's age, previous history of CVD and extracorporeal circulation (ECC) time or aortic cross-clamp time were of the risk factors for postoperative cerebral complications or not. There was significant correlation between age (p = 0.044) and/or the previous history of CVD (p < 0.001) and neurological complications. Although there was no correlation between either the duration of ECC or aortic cross-clamp time and neurological problems within the whole study population, when only the patients over 70 years old and/or having history of CVD were studied, an increased tendency towards neurological complications was seen when the ECC time was longer than 120 minutes (p = 0.045).

Aged↗

PubMed1995

Increased angiotensin converting enzyme activity in left ventricular aneurysm of patients after myocardial infarction.

OBJECTIVE: Angiotensin converting enzyme (ACE) inhibitors have been shown to improve left ventricular dysfunction and survival in patients with chronic myocardial infarction. The aim of this study was to examine the ACE activity in infarcted tissues in such patients in comparison with non-diseased tissues from control subjects obtained at necropsy. METHODS: ACE activity was measured in the left ventricles and right atrial auricles of patients (n = 9) with chronic myocardial infarction obtained at left ventricular aneurysmectomy, and in the hearts of control subjects at necropsy (n = 10). RESULTS: In non-diseased hearts, the ACE activity was highest in right atria and auricles [2.4(SEM 0.2), 2.2(0.3) nmol.mg-1 protein.min-1, NS, respectively], followed by left atria [1.7(0.2)], left auricles [1.5(0.1)], right ventricles [1.0(0.2)], and left ventricles [0.5(0.1)]. The ACE activity was significantly increased in aneurysmal tissues of patients with chronic myocardial infarction relative to left ventricles of control subjects [4.2(0.4) v 0.5(0.1) nmol.mg-1 protein.min-1, P < 0.01]. There was, however, no difference in the ACE activity of right atrial auricles between patients with chronic myocardial infarction and control subjects [2.8(0.5) v 2.2(0.3), NS]. In patients with chronic myocardial infarction, the ACE activity was higher in left ventricles than in right auricles (P < 0.01). The ACE activities in the infarcted and control ventricles were negatively correlated with the membrane protein content (r = -0.77, P < 0.01). CONCLUSIONS: In non-diseased human hearts, the ACE activity is higher in atria than in ventricles and higher in the right than in the left ventricle. Furthermore, the ACE activity in aneurysmal left ventricular tissue after myocardial infarction is higher than in non-diseased left ventricular myocardium. These results suggest that the local ACE in the human heart may play an important role in the pathophysiological state after myocardial infarction.

Adult↗

PubMed1994

Production of monoclonal antibodies and enzyme immunoassay for typical adenylate cyclase activator, Forskolin.

The ratio of hapten to bovine serum albumin in an antigen conjugate was exactly determined by matrix-assisted laser desorption/ionization mass spectrometry. A hybridoma secreting monoclonal antibodies against forskolin was produced by fusing splenocytes immunized with a forskolin-bovine serum albumin conjugate with HAT-sensitive mouse myeloma cells. The cross-reaction of anti-forskolin antibodies with 7-deacetyl forskolin was 5.57%. A very small cross-reaction appeared with 1-deoxy, 9-deoxy and 1,9-dideoxy forskolin derivatives. The full measuring range of the assay extends from 6 ng to 200 ng of forskolin. The competitive ELISA assay used for this analysis was found to be more sensitive than TLC (10 micrograms), GLC (30 ng) and HPLC (1 microgram) methods.

Adenylyl Cyclases↗

PubMed1994

Morphological observation on extrahepatic bile duct of golden hamsters fed a lithogenic diet: histochemical, ultrastructural and cell kinetic studies.

Cholelithiasis is often accompanied with disorders of the extrahepatic bile duct and pancreas. However, studies on changes of the extrahepatic bile duct in cholecystolithiasis have not shown this clearly. We therefore investigated sequential histologic changes, mucous secretion and DNA synthetic activity of the extrahepatic bile duct epithelium in cholecystolithiasis. Serial changes in the mucosal epithelial cells of the extrahepatic bile duct in golden hamsters treated with a lithogenic diet were examined by light and electron microscopy and an ultrastructural quantitative technique. In addition, epithelial cell kinetics were studied using bromodeoxyuridine (BrdU). After the 2nd week of diet, the extrahepatic bile duct showed an increase in goblet cells of the mucosal epithelium, a large number of secretory granules in the upper nuclear area of the epithelial cells and an increase in the BrdU-labeling index compared with the controls. These findings indicate that mucous secretion and cell turnover were enhanced in the mucosal epithelial cells of the extrahepatic bile duct in cholelithiasis, suggesting that the epithelial cells of the bile duct were protected and regenerating.

Animals↗

PubMed1994

Effects of 2,5-dimethylpyrazine on plasma testosterone and polyamines- and acid phosphatase-levels in the rat prostate.

The effects of 2,5-dimethylpyrazine (DMP) on plasma testosterone and levels of polyamines and acid phosphatase in the prostate of rat were studied. A high dose of DMP administered once daily for two weeks to juvenile male rats significantly decreased plasma testosterone and levels of polyamines and acid phosphatase in the prostate. These effects were not obtained by administration to mature male rats, and the inhibition was thus recognized to occur during the growth period. These findings suggest that a high dose of DMP inhibits the biosynthesis of polyamines and acid phosphatase in the prostate by decreasing the circulating testosterone level.

Acid Phosphatase↗

PubMed1994

[Study of pulmonary function after CABG with pleurotomy].

We studied the influence of pleurotomy during harvesting IMA for CABG on postoperative pulmonary function. Ninety nine cases underwent CABG surgery from January 1991 to July 1992, were divided into three subgroups, 45 patients (subgroup AY 2) having bilateral IMAs graft with pleurotomy, 45 patients (subgroup AY 1) having unilateral IMA graft with pleurotomy, 9 patients (subgroup AN) having unilateral IMA graft or vein grafts without pleurotomy. Frequencies of chest X-rays abnormality such as elevation of diaphragm and accumulation of pleural effusion before discharge around 2 weeks after surgery, were not significantly different among three subgroups. 58 cases without chest X-rays abnormalities were divided into three subgroups in the same way. There was no case with late extubation or with postoperative pulmonary complication. At first we compared pre-with postoperative pulmonary function in each subgroups. Pulmonary function (VC, FEV1.0, peak flow, MMF, V50, V25) was significantly deteriorated in the patients with pleurotomy, while VC, FEV1.0, peak flow significantly decreased, and MMF, V50 and V25 tended to decrease in the patients without pleurotomy. Moreover, magnitude of change of pulmonary function from pre- to postoperative period were not different significantly among three subgroups. In conclusions pleurotomy itself didn't appear to influence postoperative morbidity.

Coronary Artery Bypass↗

PubMed1994

[Protective effects of prostaglandin E1 on postoperative liver function after cardiac surgery].

Effects of prostaglandin E1 (PGE1) on liver function were studied in 72 patients who underwent mitral valve replacement (MVR) and coronary artery bypass grafting (CABG). The patients were divided into three groups: (A) patients with preoperative hepatic dysfunction who underwent MVR; (B) patients without previous hepatic dysfunction who underwent MVR; (C) patients without hepatic dysfunction who underwent CABG. About half of the patients in each group received PGE1 during the operation and postoperative period in the ICU. Change of serum GOT, GPT, albumin, total bilirubin, and cholinesterase (ChE) showed no difference between the patients with and without PGE1 administration in groups B and C. But, in group A, PGE1 administration significantly ameliorated the decrease of ChE, a condition which is usually observed in the first and second postoperative weeks after MVR. None of the patients showed severe hepatic dysfunction in the PGE1 group. One patient in the control group A revealed severe hepatic failure with high bilirubinemia and decreased ChE. These results suggest that the administration of PGE1 to patients with hepatic dysfunction, scheduled for MVR, might protect the liver from deterioration.

Aged↗

PubMed1993

Sustained effects of plasma norepinephrine levels on femoral-radial pressure gradient after cardiopulmonary bypass.

In order to determine the influence of the sympathetic nervous system upon the femoral-radial artery pressure gradient after cardiopulmonary bypass (CPB), we examined plasma norepinephrine levels in 34 adult male patients undergoing coronary artery bypass grafting. Cardiovascular parameters, including systolic arterial pressure, mean arterial pressure, cardiac index (CI), systemic vascular resistance index (SVRI), pulmonary artery pressure (PAP), hemoglobin (Hb) and peak dP/dt of radial and femoral artery pressures were measured after sternotomy, and immediately after the discontinuation of CPB and 90 min after CPB. Plasma norepinephrine levels were measured after sternotomy, after aortic declamping and 90 min after CPB. The patients were divided into two groups. Group A consisted of 17 patients whose femoral minus radial systolic pressure difference was 15 mmHg or more at 90 min after CPB, while Group B consisted of 17 patients with the difference less than 15 mmHg. Group A patients had significantly longer time values in the duration of both CPB (Group A 175 +/- 10 min; Group B 115 +/- 12 min, P < 0.001) and aortic cross clamping (Group A 116 +/- 7 min, Group B 71 +/- 9 min, P < 0.001). Although there was no significant difference in Hb or PAP of 90 min after CPB in Groups A and B, the following values, listed in the order of A to B, were obtained; CI, 2.79 +/- 0.10 versus 3.46 +/- 0.16 l.min(-1).m(-2) (P < 0.01); mean radial artery pressure (MRP), 58.7 +/- 2.4 versus 65.1 +/- 1.8 mmHg (P < 0.05); peak dP/dt of radial artery pressure, 568 +/- 64 versus 1026 +/- 61 mmHg.sec(-1) (P < 0.001); and plasma norepinephrine concentration, 1.81 +/- 0.25 versus 0.98 +/- 0.10 ng.ml(-1) (P < 0.01), which were statistically significant. The higher femoral-radial artery pressure gradient after CPB was observed in patients with both a longer CPB time and a higher plasma norepinephrine concentration. These results suggest that a marked constriction of peripheral arteries might have produced a damped transmission of the pressure pulse to the radial artery.

Journal Article↗

PubMed1993

[Anesthetic management of a patient undergoing hemodialysis for coronary artery bypass surgery without extracorporeal circulation].

A 58-year-old female with renal failure underwent anastomosis of the left internal mammary artery to the left anterior descending branch of coronary artery without extracorporeal circulation (ECC) and cardiac arrest. Anesthesia was maintained smoothly with modified NLA under normothermia. Without use of ECC, which often disturbs water and electrolyte metabolism, the patient's physical status remained quite stable. Though the left anterior descending artery was clamped for 20 minutes during the anastomosis, there was no complication, including perioperative myocardial infarction. For high risk patients with ECC such as patients with renal failure, respiratory failure and cerebrovascular diseases, this method is useful for the coronary artery bypass surgery.

Coronary Artery Bypass↗

PubMed1993

[A case of coronary artery bypass grafting after unsuccessful PTCA in a patient with systemic lupus erythematosis].

For angina of effort in a 69-year-old male patient who had been on steroid for SLE for 7 years we performed PTCA. However, with no dilation obtained we were compelled to perform CABG. The left internal thoracic artery was anastomosed with seg. 12 and the left great saphenous vein was anastomosed sequentially with seg. 14 and seg. 4PL. Through coronary angiography performed at postoperative 2 months, the vein graft was found well patent but in the left internal thoracic artery 90%-stenosis was observed at the anastomosed part, for which PTCA was performed to have it dilated up to 25%. In patho-histological examinations, intimal hypertrophy was observed in both grafts, which seemed to suggest a possible risk factor to determine long-term prognosis. In cases of SLE, the frequency of occurrences of ischemic heart diseases is high, indicating probabilities to be taken up as serious complication from now on. Until now, however, there are few instances reported on performing CABG for patients with SLE. We are reporting here our studies of this particular case of SLE, discussing the involvement of steroids, angitis and lupus anticoagulants as causative factors of ischemic heart diseases and related issues of surgical treatments.

Aged↗

PubMed1992

Vitronectin in liver disorders: biochemical and immunohistochemical studies.

The concentration of plasma vitronectin was determined and compared with various parameters of liver function including the blood coagulation system in patients with liver diseases. The severity of cirrhosis was graded according to Child's criteria and compared with the plasma vitronectin level. Furthermore, the distribution of vitronectin in the liver of patients with liver diseases was studied by light and electron microscopy using the indirect immunoperoxidase method. The plasma vitronectin level was low in all liver disease groups as compared with the healthy controls. The difference from the controls was significant in patients with hepatocellular carcinoma and decompensated cirrhosis. Moreover, the plasma vitronectin level was positively correlated with the levels of serum cholinesterase, albumin, plasma alpha 2 plasmin inhibitor-plasmin complex and the prothrombin time and results of the hepatoplastin test. Plasma vitronectin decreased with increasing severity of cirrhosis according to Child's criteria. These results suggest that the plasma vitronectin level is a useful parameter of hepatic synthetic function in patients with liver diseases; it may also reflect the severity of cirrhosis. Light microscopy revealed vitronectin in the area of focal necrosis and the portal tracts in the liver of patients with acute viral hepatitis, in the area of piecemeal necrosis in the liver of patients with chronic hepatitis and along the area of fiber deposition in the liver of patients with cirrhosis. Immunoelectron microscopy showed vitronectin in the rough endoplasmic reticulum of hepatocytes. Moreover, vitronectin was seen around inflammatory cells, endothelial cells, Ito cells and hepatocytes in the perisinusoidal area near focal necrosis and piecemeal necrosis and on collagen fibers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

[Morphological changes of extrahepatic bile ductal epithelia in hamsters feeded with lithogenic diet].

Experimental cholelithiasis was established by feeding hamsters with lithogenic diet. Morphological changes of extrahepatic bile ductal epithelia were observed under light and electron microscopes at weeks 1, 2, 4 and 6 after the treatment. Moreover, the changes of mucus composition in goblet cells, which were located among the epithelia, were particularly evaluated using High iron diamin-Alcian blue pH 2.5 (HID-AB) stain. Compared with the controls, goblet cells of both superior bile duct (S-BD) and inferior bile duct (I-BD) increased in number, but more prominently in I-BD than in S-BD. Furthermore, goblet cells of the controls mainly contained sulfomucin positive for the HID in their cytoplasm. On the other hand, goblet cells of the lithogenic diet group mainly contained sialomucin negative for the HID in their cytoplasm. Electron microscopy demonstrated the extensive accumulation of secretory granules in the cytoplasm of the epithelial cells of both S-BD and I-BD. These results suggest that cholelithiasis may enhance the mucus secretion from extrahepatic bile ductal epithelia, and that the mucus oversecretion results in the protective effect on biliary epithelia. On the other hand, it is suggested that the mucus oversecretion may cause the bile retention in extrahepatic bile ducts, and also may have relation to the choledochitis or pancreatitis associated with cholelithiasis.

Animal Feed↗