Biomedical subjects

R Sakata

Publications and source records attributed to R Sakata.

At least 37 records · Page 2Linked to original sources

PubMed2001

One-stage thoracic aortic aneurysm treatment and coronary artery bypass grafting.

OBJECTIVE: The treatment of thoracic aortic aneurysm accompanied by ischemic heart disease presents a surgical challenge and has up to now shown a high hospital mortality rate. This report discusses the factors contributing to improved results in these cases. METHODS: We conducted a retrospective analysis of the records of 24 consecutive patients who had undergone replacement of thoracic aorta with combined coronary artery bypass grafting (CABG) between May 1991 and October 1998. Fifteen patients received total arch replacement (Arch-with-CABG Group), and the other 9 patients received the Bentall operation (Bentall-with-CABG Group). These results were compared with those patients who had undergone replacement of the thoracic aorta without CABG (Without-CABG Group). RESULTS: In the combined CABG groups, the overall operative mortality rate was 16.7%. In comparison with the Arch-without-CABG Group, there was a significantly longer cardiopulmonary bypass time and longer selective cerebral perfusion time in the Arch-with-CABG Group. However, no significant difference was observed in postoperative complications between the two groups. In addition, there was no significant difference in either actuarial survival or the cardiac-event-free rate at 5 years between the replacement of thoracic aorta with- and without-CABG Groups (83.1% vs. 90.4%, and 78.5% vs. 77.7%, respectively). No reoperation and no late death were observed during the follow-up period (mean 21.3 months). CONCLUSIONS: We concluded that replacement of the thoracic aorta combined with CABG can be carried out safely, and that revascularization for coronary artery disease is useful for preventing any occurrence of cardiac event.

Aged↗

PubMed2001

Early results and characteristic problems associated with cardiac surgery in long-term dialysis patients.

OBJECTIVE(S): To analyze early results and characteristic problems that develop after cardiac surgery on dialysis patients. METHODS: One hundred fourteen patients on maintenance dialysis underwent cardiac surgery. Their mean age was 63.5 +/- 9.7 years, and 87 (76%) were male. The causes of chronic renal failure were diabetes mellitus in 41 (36%) and chronic glomerulonephritis in 40 (35%). Patients had previously been on dialysis for a mean duration of 7.8 +/- 5.6 years (range; 0.25-24 years). RESULTS: Fourteen (12%) were emergent cases. Eighty six patients (75%) received isolated coronary artery bypass grafting (CABG), and 10 patients underwent operations in which CABG was combined with other cardiac procedures. Twelve patients (14%) of the isolated CABG patient group (86 patients) were restricted to non-clamping bypass procedure due to severe calcification of the ascending aorta. Calcification score, which was represented by the sum of all involved coronary artery segments, was also significantly higher in dialysis patients than in the control group (4.5 +/- 2.4 segments vs. 1.5 +/- 2.1 segments, p < 0.05). Hospital mortality was 8.8% (10/114) overall, and 7% (6/86) in isolated CABG patients. The causes of deaths were as follows: intestinal necrosis in 3, arrhythmia in 2, cerebral infarction in 1, low output syndrome in 1, and sepsis in 3 (mediastinitis, pneumonia, and prosthetic valve infection). CONCLUSIONS: Long-term dialysis is a major risk factor in cardiac surgery. However, because the surgical results proved to be acceptable, long-term dialysis patients should not be denied cardiac surgery.

Aorta, Thoracic↗

PubMed2001

Coronary artery bypass grafting for dialysis patients. Effects of cardiopulmonary bypass.

OBJECTIVE: To assess the efficacy and safety of cardiopulmonary bypass during coronary artery bypass grafting (CABG) in dialysis patients. METHODS AND RESULTS: Sixty four isolated CABG patients who underwent on cardiopulmonary bypass and whose intraoperative body weight gains were accurately measured were studied retrospectively. The mean intraoperative body weight gain was 2.61 +/- 0.9 kg/m2 in the study group and 1.06 +/- 0.6 kg/m2 in controls, i.e.) 100 patients selected at random from CABG patients during the same period using cardiopulmonary bypass without chronic renal faulure, showing a statistically significant difference. Complete revascularization was successful in 98% of patients. Postoperative nonlethal complications involved brain infarction in 1 patient (1.7%), reintubation in 1 (1.7%), and paralytic ileus in 2 (3.4%). All were successfully extubated within 24 hours of surgery, and no sternal wound complications were found. Hospital mortality was 6.3% (4/64). Actuarial survival rates at 3, 5 and 8 years including all deaths were 90%, 70% and 56%, and estimated by cardiac deaths were 95%, 90%, and 90% respectively. Cardiac event free rates were 90%, 73% and 61% at 3, 5 and 8 years after CABG. CONCLUSIONS: In CABG for dialysis patients, the use of cardiopulmonary bypass demonstrates significant merits, and may expect long-term survival with minimal postoperative complications.

Adult↗

PubMed2001

Antiplatelet therapy for a pregnant woman with a mechanical aortic valve: report of a case.

A 24-year-old woman, who had undergone an aortic valve replacement with a 21-mm St. Jude Medical mechanical aortic valve, wished to have a child. She visited our department because she was aware of the risks associated with pregnancy while undergoing anticoagulant therapy using warfarin potassium. The patient opted to undergo the recommended alternative method involving the use of antiplatelet agents (dipyridamole, ticlopidine, and aspirin) in place of warfarin potassium. Antiplatelet agents were administered while regularly monitoring the platelet aggregability along with the coagulation and fibrinolytic activity. At the 36th week of gestation, antiplatelet agents were discontinued and instead were followed by continuous heparin infusion. A healthy baby was delivered by cesarean section without any complications at the 38th week. Antithrombotic therapy using antiplatelet agents appears to be an effective option for preventing serious problems for pregnant women with a mechanical heart valve.

Adult↗

PubMed2001

Balloon catheter for cyst aspiration in a thoracoscopic resection of mediastinal cysts.

In a thoracoscopic resection of mediastinal cysts, aspiration of the cyst contents at the beginning of the procedure is often helpful because it allows the cyst to be more easily grasped and manipulated. Spillage of the cyst contents into the thoracic cavity may, however, occur during aspiration when an ordinary aspiration needle is used. If the cyst contents are infective, then a subsequent contamination of the thoracic cavity may develop. We therefore use a specially designed double-balloon catheter for aspiration to minimize spillage of the cyst contents into the thoracic cavity. We describe herein the usefulness of this aspiration technique.

Catheterization↗

PubMed2001

The impact of chronic renal failure on atherosclerosis of the internal thoracic arteries.

BACKGROUND: Little is known about the impact of renal failure on atherosclerotic changes in the internal thoracic artery (ITA). METHODS: A total of 20 consecutive patients on chronic dialysis who underwent coronary artery bypass grafting (CABG) during April 1998 through September 1999 were investigated. The 20 control patients were selected from the same interval to rigorously match risk factors. Atherosclerosis of the ITA collected from each patient was analyzed using the subjective evaluation proposed by Kay and colleagues. RESULTS: There were no cases of greater than 25% atherosclerotic luminal narrowing among a total of 35 ITA specimens from dialysis patients. The degree of atherosclerosis was not significantly different from that of the specimens from matched patients (p = 0.18). No calcification was found in ITA grafts either microscopically or macroscopically. The number of elastic lamellae, an index of the elasticity of the ITA graft, was not significantly different from those obtained from the matched patients. Analysis of preoperative coronary angiography revealed that coronary calcification was significantly more frequent in dialysis patients (15 patients, 75%) than in matched patients (p < 0.05). By analysis of postoperative angiography in dialysis patients, no evidence of atherosclerotic changes was found in 28 opacified ITAs. In addition, despite the presence of calcification in the native coronary, no calcification was evident along the entire length of the ITAs. CONCLUSIONS: This study revealed the minimal impact of chronic renal failure on atherosclerotic changes in the ITA. The results of this study support the continued use of ITA grafting in dialysis patients.

Aged↗

PubMed2001

Growth potential of left internal thoracic artery grafts: analysis of angiographic findings.

BACKGROUND: The growth potential of the internal thoracic artery (ITA) is still undetermined, and little is known about the long-term effects of anastomosing it to the coronary artery. METHODS: Fifty-three patients whose left ITA (LITA) had been anastomosed to the left anterior descending (LAD) coronary artery underwent coronary angiography within 1 month of operation and in late follow-up (mean interval: 4.5 +/- 1.5 years). The diameter ratios of LITA to LAD were designated as the matching ratio. RESULTS: In follow-up, the diameter of the LITA increased from 1.83 +/- 0.40 to 2.46 +/- 0.53 mm in the 29 patients with progressive proximal native coronary stenosis. However, late results indicate that the matching ratio did not vary according to the location of the LITA anastomosis on the LAD (proximal portion: 1.13 +/- 0.16, distal portion 1.19 +/- 0.13), and reached an upper limit of about 1.4. CONCLUSIONS: Growth potential of the LITA is limited by the diameter of the coronary artery onto which it is anastomosed. The most effective procedure for enhancing the growth potential of the LITA is to anastomose as proximally as possible onto the LAD.

Adult↗

PubMed2001

Bilateral internal thoracic artery use for dialysis patients: does it increase operative risk?

BACKGROUND: The efficacy and risk of using the bilateral internal thoracic artery (BITA) for coronary artery bypass grafting in dialysis patients is virtually unknown. METHODS: Twenty-five patients on dialysis who underwent coronary artery bypass grafting using the BITA were retrospectively studied (BITA group). For comparison purposes, 52 patients on dialysis who underwent coronary artery bypass grafting using the left ITA were selected (LITA group). RESULTS: No wound healing problems occurred in the BITA group. Mean postoperative bleeding volume was 1,427 +/- 808 mL and 800 +/- 508 mL in the BITA and LITA groups, respectively (p = 0.00009). Blood transfusions for the BITA and LITA groups required an average of 6.8 and 6.2 units of packed red blood cells, respectively, with no significant difference. Five patients in the BITA group (20%) showed severe atherosclerotic deterioration of the ascending aorta, precluding clamping. Hospital mortality was 4% (1 of 25 patients) in the BITA group and 7.7% (4 of 52 patients) in the LITA group, with no significant difference (p = 0.49). CONCLUSIONS: In patients on dialysis, especially those with severe atherosclerotic or calcified deterioration of the ascending aorta, coronary artery bypass grafting using BITA grafting (arterial in situ conduits) may offer the easiest and most suitable solution without increased operative risk.

Adult↗

PubMed2001

Technical aspects and outcome of in situ right internal thoracic artery grafting to the major branches of the circumflex artery via the transverse sinus.

BACKGROUND: Little is known about the anatomic limitations of in situ right internal thoracic artery (RITA) grafting to the circumflex artery. METHODS: To evaluate the technical aspects and outcome of revascularization of the proximal and distal major branches of the circumflex artery (obtuse marginal [OM] branch and posterolateral [PL] branch), a total of 145 patients who possessed a graftable branch of the circumflex artery were enrolled into the prospective project. There were 73 patients who had the PL branch as a primary target and 72 patients with OM branches, which were allocated by a blinded observer who reviewed the preoperative angiography. RESULTS: Changes of primary target vessels were required in 9 patients (6.2%), yielding an overall success rate of RITA grafting of 93.8%. The success rates of RITA grafting to the OM branch and the PL branch were 95.8% (69/72; CI 88.3% to 99.1%) and 91.7% (67/73; CI 83.0% to 96.9%), respectively. The univariate analysis identified grafting under hypothermic ventricular fibrillation as predictors of inability to use in situ RITA grafting for revascularization of the circumflex artery. RITA grafting to the PL branch is not identified as a predictor. Postoperative angiography in 136 patients revealed only one occlusion (0.75%) of the RITA graft anastomosed to the marginal artery. There were no significant differences in patency rates between left and right ITA grafts. CONCLUSIONS: This prospective study showed that in situ RITA was, in most cases, able to reach most branches of the major circumflex artery and demonstrated an excellent patency rate.

Adult↗

PubMed2001

Estrogen upregulates nitric oxide synthase expression in cultured rat hepatic sinusoidal endothelial cells.

BACKGROUND/AIMS: Estrogen receptor (ER) is present in vascular endothelial cells and estrogen promotes nitric oxide (NO) synthesis, which relaxes smooth muscle cells. It is also speculated that NO is synthesized by estrogen in hepatic sinusoidal endothelial cells (SECs). Here we investigated the localization of ER and endothelial cell nitric oxide synthase (ecNOS), and determined 17beta-estradiol (E2)-induced ecNOS expression in normal rat SECs. METHODS: Cultured SECs were used. Fluorescence intensities of ecNOS were measured by immunofluorescence using a confocal laser-scanning microscope. E2 was added (100 pg/ml) to the culture medium, and the expressions of ecNOS mRNA and protein were analyzed by reverse-transcription polymerase chain reaction and Western blotting. NO production in cultured SECs was examined using diaminofluorescein-2 diacetate as a fluorescent indicator for NO. RESULTS: Immunolocalization of ER and ecNOS in normal liver was demonstrated in endothelial cells lining the hepatic sinusoids. ER and ecNOS were localized in the nuclei and cytoplasm of cultured SECs, respectively. The mRNA expression of ecNOS in cultured SECs was increased after 6 h, and the protein expression of ecNOS was increased 24 h after E2 stimulation. The fluorescence intensity of NO in cultured SECs was increased by E2 stimulation compared with untreated control cells. CONCLUSIONS: These results suggested that ER is present in SECs, and estrogen upregulates NO production in SECs. E2 may be involved in the regulation of the hepatic sinusoidal microcirculation.

Animals↗

PubMed2001

A leukocyte depleting filter reduces endothelial cell dysfunction and improves transplanted canine heart function.

BACKGROUND: To date leukocytes have been known to play a major role in reperfusion injury and have directed attention to leukocyte-endothelium interaction. This study was designed to investigate how much graft viability and the coronary microcirculatory function could be preserved by leukocyte depletion (LD) in a model of orthotopic cardiac transplantation. METHODS: The heart in 10 beagle dogs was arrested by introducing a 4 degrees C St. Thomas' cardioplegic solution. They were harvested, immersed in the cold saline for 3 hours, and then orthotopically transplanted. Five recipients underwent LD (LD group) at reperfusion with the use of a Pall BC1B leukocyte depleting filter inserted into the cardiopulmonary bypass (CPB) circuit. The other 5 dogs without filtration served as a control group. RESULTS: Leukocytes were about 80% filtrated and neutrophils were also 85% filtrated during the first 30 minutes of reperfusion in the LD group. A high level of adenosine triphosphate was maintained after transplantation in the LD group. The polymorphonuclear elastase level was significantly lower in the LD group. The cardiac function assessed by the slopes of the end-systolic pressure volume relation after transplantation was significantly higher in the LD group than in the control group (p < 0.05). The coronary vascular resistance responses to acetylcholine and nitroglycerin after transplantation were preserved significantly better in the LD group than in the control group (p < 0.05). CONCLUSIONS: These results suggest that a leukocyte depleting filter placed in the CPB circuit would prevent leukocyte-mediated endothelial cell injury, improve microcirculation of the myocardium, and lead to excellent graft function.

Animals↗

PubMed2001

Effect of a neutrophil elastase inhibitor (ONO-5046 Na) on ischemia/reperfusion injury using the left-sided heterotopic canine heart transplantation model.

BACKGROUND: Ischemia/reperfusion injury is a major cause of transplanted heart dysfunction. Several reports have demonstrated that polymorphonuclear neutrophil (PMN) elastase derived from the activated neutrophils might play an important role in this injury. Herein, we investigated the protective effects of PMN elastase inhibitor (ONO-5046 Na) on ischemia/reperfusion injury using a left-sided canine heterotopic heart transplantation model. METHODS: We used 10 pairs of adult beagle dogs. The donor heart was transplanted heterotopically into the left thoracic cavity of the recipient without cardiopulmonary bypass. A bolus of ONO-5046 Na (10 mg/kg) was introduced intravenously to 5 recipients (group II) at 15 minutes before reperfusion and was followed by continuous infusion (10 mg/kg per hour) for 180 minutes. Five dogs (group I) did not receive ONO-5046 Na and thus served as a control. After reperfusion, we evaluated transplanted heart function and obtained blood samples from the coronary sinus over a 360-minute period. RESULTS: E(max) and pre-load recruitable stroke work in group II showed significantly better recovery than group I. Blood levels of PMN elastase, creatine kinase MB, lactate and inflammatory cytokines (tumor necrosis factor-alpha, interleukin-6, interleukin-8) were significantly lower in group II. Depletion of myocardial concentration of adenosine triphosphate at 120 minutes after reperfusion and myocardial water content was significantly lower in group II. CONCLUSIONS: ONO-5046 Na, which inhibits PMN elastase, could reduce ischemia/reperfusion injury in heart transplantation. These results indicate that clinical application of ONO-5046 Na should be considered.

Animals↗

PubMed2001

Hes7: a bHLH-type repressor gene regulated by Notch and expressed in the presomitic mesoderm.

BACKGROUND: Whereas Notch signalling is essential for somitogenesis, mice deficient for the basic helix-loop-helix (bHLH) genes Hes1 and Hes5, downstream Notch effectors, display normal somite formation, indicating that there may be an as-yet unidentified Hes1-related bHLH gene. RESULTS: We identified a novel bHLH gene, designated Hes7, from mouse embryos. Hes7 has a conserved bHLH domain in the amino-terminal region and the WRPW domain at the carboxy-terminal end, like Hes1. The mouse Hes7 gene is located next to Aloxe3, which is mapped to a position 37.0 cM from the centromere on chromosome 11. In a transfection analysis, Hes7 represses transcription from the N box- and E box-containing promoters. In addition, Hes7 suppresses the E47-induced transcriptional activation. Promoter analysis indicated that Hes7 expression is controlled by Notch signalling. Strikingly, Hes7 is specifically expressed in the presomitic mesoderm in a dynamic manner. We also identified two related bHLH genes from human: one is closely related to mouse Hes7 and therefore designated hHes7 and the other designated hHes4. CONCLUSION: The structure, transcriptional activity and expression pattern in the presomitic mesoderm of Hes7 are very similar to those of Hes1, suggesting that Hes7, together with Hes1, may play a role in somite formation under the control of Notch signalling.

Amino Acid Sequence↗

PubMed2001

Effects of sarpogrelate hydrochloride on adenosine diphosphate- or collagen-induced platelet responses in arteriosclerosis obliterans.

To evaluate the effects of the 5-HT2 receptor antagonist sarpogrelate hydrochloride (sarpogrelate) on platelet responses in arteriosclerosis obliterans (ASO), we examined platelet aggregation and its relationships to platelet-derived growth factor (PDGF), soluble P-selectin (sP-selectin), and transforming growth factor-beta 1 (TGF-beta1). Circulating plasma levels of PDGF and sP-selectin in 13 patients with ASO after 1 week of medication with sarpogrelate were significantly lower than those before medication. In contrast, circulating plasma levels of TGF-beta1 after medication were significantly higher than those before medication. When platelet-rich plasma obtained from ASO patients after medication was stimulated with adenosine diphosphate (ADP) or collagen, platelet aggregation was suppressed compared with rates before medication. Significant decreases in levels of PDGF, sP-selectin and TGF-beta1 released from platelets in response to 5 micromol/l ADP and 1 microg/ml collagen after taking of sarpogrelate were found. There were close correlations between platelet aggregation and respective molecules released from platelets. In conclusion, since platelet activation is involved in pathogenesis of thrombotic disease, sarpogrelate may suppress the development of obstructive arteriosclerosis. PDGF and TGF-beta1, as well as sP-selectin, appear to be useful markers for clinical evaluation of anti-platelet drugs.

Adenosine Diphosphate↗

PubMed2001

Relation of type II transforming growth factor-beta receptor to hepatic fibrosis and hepatocellular carcinoma.

Hepatocarcinogenesis is closely related to hepatic fibrosis. In this study, we investigated the relationship of type II transforming growth factor-beta receptor (T beta RII) to hepatic fibrosis and hepatocellular carcinoma (HCC). In vivo: liver tissues were obtained from 30 patients (10 chronic hepatitis, 7 cirrhosis, 13 HCC). Protein expression and immunolocalization of T beta RII were examined by Western blot analysis and immunohistochemistry. In vitro: T beta RII protein expression in hepatoma cell lines (HepG2, Hep3B, HLE, HLF and Huh7) was examined by Western blot analysis. Next, we transfected T beta RII cDNA to Huh7, and compared the change of cell number and observed the induction of apoptosis after TGF-beta1 treatment using a FACScan flow cytometer. In vivo: T beta RII immunolocalization in liver tissues was significantly decreased in patients with HCC compared with that of patients with chronic hepatitis or liver cirrhosis. In Western blot analysis, T beta RII expression in tissues attenuated in comparison with that in non-tumor tissues in some patients with HCC. In vitro: T beta RII protein expression in HLE, HLF and Huh7 cells was weaker than that in HepG2 and Hep3B cells. In Huh7 cells transfected T beta RII cDNA, cell arrest and apoptosis were obviously induced. These results indicated that human HCC has a reduced expression of T beta RII for TGF-beta1. This may provide a selective growth advantage to HCC to escape the inhibitory growth signals of TGF-beta1, and may be linked with critical steps in the growth of hepatoma cells.

Aged↗

PubMed2001

Coronary artery bypass grafting for dialysis patients: usefulness of multiarterial bypass.

This study assessed the efficacy of multiarterial bypass in coronary artery bypass grafting (CABG) in dialysis patients. Eighty dialysis patients who underwent CABG were divided into 2 groups. Group A consisted of 38 patients in whom the left internal thoracic artery and additional saphenous vein graft (SVG) had been used. Group B consisted of 42 patients in whom 2 or 3 arterial grafts and additional SVGs had been used. No mediastinitis was shown in either group. Actuarial survival rates, including all deaths, and estimated by cardiac deaths at 8 years, were 28% and 83%, respectively, in Group A and 93% and 100%, respectively, in Group B with a significant difference (p = 0.014 and 0.016, respectively). Cardiac event-free rates at 8 years were 43% and 96% in Groups A and B, respectively, with a significant difference (p = 0.0016). Multiarterial grafting improved long-term results after CABG for dialysis patients compared with single internal thoracic artery grafting with minimal complications related to graft harvesting.

Coronary Artery Bypass↗

PubMed2001

Double left renal vein associated with abdominal aortic aneurysm.

Double left renal vein is a rare venous anomaly. We operated on 72-year-old man of abdominal aortic aneurysm (AAA) with double left renal vein. Massive hemorrhage was encountered during encircling the tape around the abdominal aorta. One vein passing posterior to the aorta was injured. Further dissection revealed the presence of double left renal vein forming a ring around the aorta. The patient underwent an abdominal aortic replacement following prompt repair of the injured vein. He had an uneventful postoperative course without renal complication. We missed that preoperative computed tomographic (CT) scan had demonstrated double left renal vein. Preoperative contrast-enhanced CT scan is useful and essential not only for evaluation of AAA, but also for establishing the presence of venous anomalies. Venous anomalies should be taken into consideration on the AAA operation.

Aged↗

PubMed2001

[A case of diffuse alveolar hemorrhage developing after open heart surgery].

A 47-year-old man was receiving anticoagulant therapy after coronary artery bypass grafting and mitral valve plasty. A chest roentgenogram disclosed alveolar infiltrates throughout both lung fields 6 months postoperatively. Lung biopsy specimens showed the presence of hemosiderin-laden macrophages in the alveolar spaces, establishing a diagnosis of diffuse alveolar hemorrhage. Anticoagulant therapy may have caused the hemorrhage, because the patient had no immunologic disorder or renal disease. The shadows completely disappeared after steroid therapy and discontinuation of anticoagulant therapy. Diffuse alveolar hemorrhage should be considered, when extensive infiltrates develop on chest roentgenogram in patients receiving anticoagulant therapy after open heart surgery. Lung biopsy is essential, when a bronchoalveolar lavage fails to diagnose the disease.

Cardiac Surgical Procedures↗