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Y Yokoi

Publications and source records attributed to Y Yokoi.

At least 19 recordsLinked to original sources
PubMed2004

Photodynamic therapy for malignant biliary obstruction: a case series.

We describe four elderly patients (age range 73-85 years) with bile duct carcinoma who were treated with photodynamic therapy. These patients could not be treated surgically because of the presence of cardiopulmonary disease and the extent of the bile duct carcinoma. Prior to photodynamic treatment the patients underwent percutaneous transhepatic biliary drainage (PTBD) to relieve jaundice. The photodynamic therapy was carried out under percutaneous transhepatic cholangioscopy, 2 days after intravenous administration of sodium porfimer (2 mg/kg). Excimer dye laser was used to irradiate the obstructive lesion with an energy dosage of 50 J/cm2 (total irradiation dose 150-250 J/cm2) and stenotic site with a dosage of 50-100 J/cm2. Photodynamic therapy was achieved safely without occurrence of cholangitis in all patients, and was followed by metallic stent placement, resulting in the improvement of performance levels in three patients who did not have liver metastases. Photodynamic therapy via the PTBD route is a safe and promising palliative therapy for selected elderly patients with bile duct carcinoma.

Aged↗
PubMed2004

[Evaluation of spinal cord ischemia in endovascular stent graft repair and surgical operation of descending thoracic or thoracoabdominal aortic aneurysms].

Between October 1996 and June 2003, endovascular stent graft repair was performed in 87 patients with descending thoracic aortic aneurysms, graft replacement was performed in 24 patients with thoracoabdominal aortic aneurysms, and endovascular stent graft repair with concomitant surgical bypass of abdominal visceral arteries was performed in 3 patients with thoracoabdominal aortic aneurysms. The retrievable stent graft was inserted and evoked spinal cord potential were monitored in order to predict spinal cord ischemia for stent graft repair. There was no paraplegia or hospital death, although 3 patients had paraparesis in stent graft repair. Two of the 3 patients with paraparesis made a full neurologic recovery. There were no cases of paraplegia or paraparesis in surgical operations with thoracoabdominal aortic aneurysm. The concomitant surgical procedure was a good technique for patients in whom cardiopulmonary bypass could not be used. Our results of stent graft repair and surgical operation for descending thoracic or thoracoabdominal aortic aneurysms were acceptable. The retrievable stent graft was useful for prediction of spinal cord ischemia before endovascular stent graft repair of descending thoracic or thoracoabdominal aortic aneurysm.

Adult↗
PubMed2003

Combined minimally invasive procedure for descending thoracic aortic aneurysm with left main coronary artery disease.

A 78-year-old man had a descending thoracic aortic aneurysm with left main coronary artery disease. Combined beating heart coronary artery bypass and endovascular thoracic aortic aneurysm repair was performed without cardiopulmonary bypass. The left anterior descending artery and the obtuse marginal branch of the left circumflex artery were revascularized through a left antero-lateral small thoracotomy. The aneurysm was excluded with stent grafts through a small femoral incision. This combined less invasive procedure is a promising approach providing better surgical results in patients with thoracic aortic aneurysm and severe coronary artery disease.

Aged↗
PubMed2001

Simple detection of severe coronary stenosis using transthoracic Doppler echocardiography at rest.

Coronary flow velocity can be measured by transthoracic Doppler echocardiography (TTDE). The purpose of this study was to detect severe coronary stenosis using the diastolic-to-systolic flow velocity ratio (DSVR) determined by TTDE at rest. We prospectively examined 190 consecutive patients with angina pectoris for whom coronary angiography was planned. Doppler spectral tracings of flow velocity in the distal left anterior descending artery were recorded by TTDE at rest. The mean and peak DSVR values were computed using mean and peak coronary flow velocities. DSVR measurement by TTDE at rest was performed within 24 hours before angiography, and in patients who underwent coronary intervention it was performed again within 48 hours after the intervention. The success rate for DSVR measurement by TTDE was 83.7%. There were significant differences in peak DSVR and mean DSVR between the patients with severe stenosis (percent diameter stenosis >85%) and those without severe stenosis (1.3 +/- 0.4 vs 1.9 +/- 0.50 and 1.2 +/- 0.4 vs 1.8 +/- 0.5, respectively; p <0.0001). In the 17 patients with successful intervention, DSVR was significantly increased after the procedure (mean 1.2 +/- 0.1 vs 2.0 +/- 0.2; peak 1.2 +/- 0.2 vs 2.0 +/- 0.3, respectively; p <0.0001). For percent diameter stenosis >85%, the best cut-off points were 1.6 for peak DSVR (sensitivity 79.0%, specificity 75.7%) and 1.5 for mean DSVR (sensitivity 77.0%, specificity 77.9%). Thus, DSVR measurement by TTDE is a simple, noninvasive method for detection of severe coronary stenosis at rest.

Adult↗
PubMed2001

Intrahepatic cholangiojejunostomy for unresectable malignant biliary tumors with obstructive jaundice.

We reviewed our experience with intrahepatic cholangiojejunostomy as a palliative therapy for patients with unresectable malignant diseases involving the ductal confluence or the common hepatic duct. Fifteen patients with malignant biliary obstruction were treated by cholangiojejunostomy at our hospital. Two patients had intrahepatic cholangiocarcinoma, 7 had gallbladder carcinoma, 5 had bile duct carcionoma, and 1 had pancreatic carcinoma. Segment III cholangiojejunostomies were performed in 14 patients and segment V cholangiojejunostomy in 1. Contraindications for surgical resection were locoregional invasion of tumors involving the proper and/or common hepatic artery and portal vein in 15 patients and the presence of hepatic metastases in 6 patients. Liver metastases were detected in 5 of the 7 patients with gallbladder carcinoma. Postoperative complications occurred in 2 patients (13%), but there was no leakage of the cholangioenteric anastomosis in our series. There was no operative mortality after cholangiojejunostomy. Of the 9 patients who survived for more than 6 months after surgery, 7 showed a significant improvement in performance status (PS) (82 +/- 10%) 3 months after the surgery compared with the preoperative PS (70 +/- 7%). Four of the 9 patients had recurrent cholangitis as a late complication, but 4 were completely free from jaundice. Median survival after cholangioenteric bypass was 9 months (range, 2-25 months). With respect to tumor location, the median survival time was 4 months (range, 2-25 months) in patients with gallbladder carcinoma and 15.5 months (range, 12-22 months) in those with bile duct carcinoma. While the median survival period after surgery was only 3 months (range, 2 to 8 months) in the 5 patients with hepatic metastases from gallbladder carcinoma, 2 patients without liver metastasis survived for 9 and 25 months after segment III cholangioenteric bypass. In conclusion, cholangiojejunostomy can provide useful palliation for malignant biliary obstruction when combined with careful patient selection.

Bile Duct Neoplasms↗
PubMed2001

Impact of repeat hepatectomy on recurrent colorectal liver metastases.

BACKGROUND: Hepatic recurrence is seen in approximately 40% of patients undergoing hepatectomy for colorectal metastases. This study was designed to assess the risks and clinical benefits of repeat hepatectomy for those patients. METHODS: Twenty-six patients underwent repeat hepatectomy for hepatic recurrence, and their clinical data were retrospectively reviewed for operative morbidity and mortality, performance level, and survival. RESULTS: There was no operative mortality after repeat hepatectomy. Operative bleeding was significantly increased in the second hepatectomy; but operating time, duration of hospital stay, and performance status after the second hepatectomy were comparable with those of the initial hepatectomy. The median survival time from the second hepatectomy was 31 months, and the 3- and 5-year survival rates were 62% and 32%, respectively. A short disease-free interval (6 months or less) between the initial hepatectomy and diagnosis of hepatic recurrence in the remnant liver was significantly associated with poor survival after the second hepatectomy. CONCLUSIONS: Repeat resection contributed to clinical benefits for selected patients with hepatic recurrence after the initial hepatectomy for colorectal liver metastases. However, appearance of hepatic recurrence within 6 months or less after the initial hepatectomy is a poor prognostic factor for repeat hepatectomy.

Adult↗
PubMed2001

Coronary artery bypass grafting in patients with dialysis-dependent renal failure.

The aim of this study was to define short- and long-term results of coronary artery bypass grafting (CABG) in dialysis patients. A retrospective review was carried out on 73 consecutive patients dependent on chronic dialysis who underwent CABG. In 63 isolated CABGs, 9 operations were performed under normal beating heart because of severe atherosclerotic changes in the ascending aorta or carotid arteries. The operative mortality (30 days' mortality) was 4.1%, and causes of death were closely related to cardiopulmonary bypass use. In the last 29 operations after introduction of the beating heart bypass, no hospital deaths occurred. The actual survival rates dropped to 45% at 70 months mainly for noncardiac late death. CABG for dialysis patients as undertaken with an acceptable operative risk. Extended application of beating heart bypass to these patients may produce further positive early results.

Adult↗
PubMed2001

[Indications for and techniques of hepatic vein reconstruction in hepatectomy for hepatocellular carcinoma].

The indications for hepatic vein reconstruction (HVR) in resection of segments 7 and 8 for hepatocellular carcinoma (HCC) have been controversial. Although right hepatic vein ligation may not cause complications in some patients, hepatic parenchymal congestion and liver dysfunction occur in others. We performed HVR using autovein grafts in 6 HCC patients, patch grafts in 3, and direct anastomosis in 1, respectively. From this experience, we consider that HVR may be indicated in patients with a discolored hepatic area after hepatic vein ligation, and without inferior right hepatic vein and intrahepatic venous communication. Furthermore, although repeat hepatectomy has resulted in improved survival in patients with recurrent hepatic tumors, when the right hepatic vein has already been ligated, numerous intrahepatic communicating vein anastomoses develop. In repeat hepatectomy in such patients, uncontrollable massive bleeding from hepatic veins occurs. Therefore, HVR is recommended to maintain the previous hepatic vein anatomy. Recently, the indications for HVR have been studied to prevent hepatic vein congestion and liver dysfunction in both the remant and graft livers in living-related donor partial liver transplantation from the standpoint of hemodynamics. Additionally, the technique of direct hepatic vein anastomosis is presented.

Carcinoma, Hepatocellular↗
PubMed2001

[Feeding methods for long-term bedridden patients with dysphagia under home health care--percutaneous endoscopic gastrostomy (PEG) and intravenous hyperalimentation (IVH)].

We began home health care in our hospital in 1992, and the total number of patients under home health care has reached 380 so far. We report 12 bedridden patients with dysphagia, who have obtained nutrition using two feeding methods. The patients are 7 men and 5 women, with a mean age of 81.4 +/- 8.8 years. The diseases in these patients include cerebrovascular diseases, Parkinson's disease, and senile dementia of the Alzheimer type. The feeding methods include swallowing after swallowing training, percutaneous endoscopic gastrostomy (PEG), and intravenous hyperalimentation (IVH). We have fed these patients by combinating these three methods. The patients fed by swallowing and PEG, swallowing and IVH, and PEG and IVH are five, five and two, respectively. It is very important for bedridden patients to eat and swallow food by themselves, even if the amount is extremely small. Although swallowing training has been performed, the amount of food is not sufficient for life support. Therefore, additional feeding by PEG or IVH is necessary. Sufficient nutrition through a variety of feeding methods is important for patients under home health care.

Aged↗
PubMed2000

Radioimmunoassay for orexin A.

A radioimmunoassay for orexin A has been developed. Anti-orexin A antiserum was raised in New Zealand white rabbits immunized with a conjugate of synthetic orexin A with bovine serum albumin. This antibody did not crossreact with orexin B, hypothalamic hormones, pituitary hormones, neuropeptides or gut hormones. Radioiodination of orexin A was performed with the chloramin T method, followed by purification of radioiodinated material on Sephadex G-25 column. Orexin A was extracted from tissues using acid-acetone. The assay was performed with a double antibody system. The dilution curve of acid-acetone-extracts of rat hypothalamus in the radioimmunoassay system was parallel to the standard curve. The recovery of tissue orexin A was about 80%,and the intra-assay and inter-assay variations were 5.2% and 7.8%, respectively. Orexin A was found in the hypothalamus, cerebrum and testis. These data suggest that this assay system is suitable for the measurement of tissue orexin A and that orexin A is found in the central nervous system and testis.

Animals↗
PubMed2000

Radioimmunoassay for hypocretin-2.

OBJECTIVE: To develop radioimmunoassay for hypocretin-2 (Hcrt-2). And search for its presence in certain rat tissues. METHODS: Anti-Hcrt-2 serum has been raised in New Zealand white rabbits immunized with a conjugate of synthetic Hcrt-2 with bovine serum albumin. Radioiodination of Hcrt-2 was performed by chloramine T method, followed by purification of radoiodinated material on Sephadex G-25 column. RESULTS: The obtained antibody did not cross react with hypocretin-2, hypothalamic hormones, pituitary hormones, neuropeptides or gut hormones. The assay was performed with a double antibody system. Hcrt-2 was extracted from the tissues with acid acetone. The dilution curve of acid acetone extracts of rat hypothalamus in the radioimmunoassay system was parallel to the standard curve. The recovery of tissue Hcrt-2 was about 85 % and the intra-assay and inter-assay variation were 5.6 % and 8.0 %, respectively. Hcrt-2 was found in the hypothalamus, cerebrum, brain stem and testes. CONCLUSIONS: The obtained data suggest that the assay system developed is suitable to measure Hcrt-2 in tissues and that Hcrt-2 is mainly found in the hypothalamus.

Animals↗
PubMed1999

Origin, kinetics, and function of chimeric B lymphocytes in liver allografts.

BACKGROUND: Despite the well-recognized concordance of chimerism with spontaneous acceptance of rat liver allografts, the active role and the identity of chimeric cells mediating liver allograft tolerance are unknown. Because resting B cells are endowed with a tolerogenic antigen-presenting capacity, we assessed whether donor B cells propagated from the grafted liver may be responsible for liver allograft tolerance. METHODS: Dark Agouti or Lewis rats were grafted with Lewis or Dark Agouti livers as a tolerogenic or a rejection combination, respectively. We followed the kinetics of donor B cells in recipients by flow cytometry, and we examined the fate of liver allografts depleted of passenger B cells in either B cell-sufficient or -deficient recipients. B-cell depletion was achieved by treatment of animals with polyclonal goat anti-rat IgM antibody from birth. RESULTS: During the first 3 days after liver allografting, donor B cells rapidly migrated from graft-infiltrating cells and appeared in systemic circulation in both the tolerogenic and rejection combinations. However, systemic chimerism was detectable in the tolerogenic combination by day 14, whereas it was undetectable in the rejection combination by day 7. In graft-infiltrating cells, a significant expansion of chimeric IgM+ (newly formed) B cells was observed on day 5 in the tolerogenic, but not in the rejection, combination. However, depletion of B cells from liver grafts and the absence of antibodies failed to alter the outcome of liver allograft survival in the tolerogenic or immunogenic combination. CONCLUSION: Although intragraft chimeric B cells proliferated in tolerogenic liver allografts, their clonal expansion does not seem to be essential for the promotion of liver allograft tolerance.

Animals↗
PubMed1999

Relationship between blood pressure and heart-rate variability during graded head-up tilt.

To investigate the relationship between change in blood pressure and autonomic nerve activity, two types of head-up tilt experiments were performed. One was a 30 degrees, 45 degrees, 60 degrees, and 90 degrees graded tilt-up, in which tilt angles were changed at 6-min intervals and 5 min were spent at each angle. The other was a 10-min lasting head-up tilt at 60 degrees. Electrocardiogram (ECG) and blood pressure (Finapres) of 18 healthy non-smoking subjects (9 men, 9 women) were recorded during the experiments. Heart-rate variability was examined by general spectral analysis (GSA). The high-frequency/total-area ratio (HF/TO) showed a decrease as the tilt angle increased. Compared with the values at the 0 degrees position, these changes were statistically significant (P < 0.05). The low-frequency/HF ratio (LF/HF) showed a significant (P < 0.05) difference between 0 degrees and 90 degrees, and between 30 degrees and 90 degrees. Some of the subjects could not maintain their blood pressure during either of the head-up tilt experiments, and they showed only a slight change in HF/TO and LF/HF. This result confirmed that immediate responses to head-up tilt reflect autonomic nerve activity. Hence, changes in the frequency components were found to be an index of autonomic nerve activity, and they explained the individual differences observed in the ability to control blood pressure during a transition to upright posture.

Adolescent↗
PubMed1999

Prevention of autoimmune recurrence and rejection by adenovirus-mediated CTLA4Ig gene transfer to the pancreatic graft in BB rat.

Type 1 diabetes is the result of a selective destruction of pancreatic islets by autoreactive T-cells. Therefore, in the context of islet or pancreas transplantation, newly transplanted beta-cells are threatened by both recurrent autoimmune and alloimmune responses in recipients with type 1 diabetes. In the present study, using spontaneously diabetic BB rats, we demonstrate that whereas isolated islets are susceptible to autoimmune recurrence and rejection, pancreaticoduodenal grafts are resistant to these biological processes. This resistance is mediated by lymphohematopoietic cells transplanted with the graft, since inactivation of these passenger cells by irradiation uniformly rendered the pancreaticoduodenal grafts susceptible to recurrent autoimmunity. We further studied the impact of local immunomodulation on autoimmune recurrence and rejection by ex vivo adenovirus-mediated CTLA4Ig gene transfer to pancreaticoduodenal grafts. Syngeneic DR-BB pancreaticoduodenal grafts transduced with AdmCTLA4Ig were rescued from recurrent autoimmunity. In fully histoincompatible LEW-->BB transplants, in which rejection and recurrence should be able to act synergistically, AdmCTLA4Ig transduced LEW-pancreaticoduodenal allografts enjoyed markedly prolonged survival in diabetic BB recipients. In situ reverse transcription-polymerase chain reaction revealed that transferred CTLA4Ig gene was strongly expressed in both endocrine and exocrine tissues on day 3. These results indicate the potential utility of local CD28-B7 costimulatory blockade for prevention of alloimmune and autoimmune destruction of pancreatic grafts in type 1 diabetic hosts.

Abatacept↗
PubMed1999

Distribution of calcium sensing receptor in rats: an immunohistochemical study.

OBJECTIVE: To investigate the organ distribution of calcium sensing receptor (CaR) in rats by immunohistochemical method. METHODS: CaR was identified immunohistochemically in the rat tissues using specific anti-CaR antiserum raised in New Zealand white rabbits immunized with a conjugate of synthetic CaR peptide (186-204) with bovine serum albumin. Immunohistochemical analysis was performed by avidin-biotin complex method. RESULTS: CaR immunoreactivity was visualized in the central nervous system, anterior pituitary, gastric mucosa, small intestine and colon, Auerbach,s and Meissner,s gastric nervous branch, small intestine and colon, pancreas, adrenal medulla, kidney and testis. When using antiserum preincubated with synthetic CaR peptide (186-206) or kidney homogenates, no significant stain of kidney was detected. CONCLUSIONS: The findings suggest that CaR is widely distributed and that the method used is valuable in studying the distribution of caR in rat.

Amino Acid Sequence↗
PubMed1999

Distribution of thyrotropin releasing hormone receptor type 2 in rats: an immunohistochemical study.

OBJECTIVE: To investigate the organ distribution of thyrotropin releasing hormone receptor (TRHR) type 2 in rats by immunohistochemical method. METHODS: TRHR type 2 was identified immunohistochemically in the rat tissues using specific anti-TRHR antiserum raised in New Zealand white rabbits immunized with a conjugate of synthetic TRHR type 2 (5-23) with bovine serum albumin. Immunohistochemical analysis was performed by avidin-biotin complex method. RESULTS: TRHR type 2 immunoreactivity was visualized in the central nervous system, anterior pituitary, gastric mucosa, Auerbach's and Meissner's nervous branch of the stomach, small intestine and colon, retina amd testis. Significant stain was detected in neural perikarya, axons and dendrites. When using antiserum preincubated with synthetic TRHR type 2(5-23) or anterior pituitary homogenates, no significant stain of anterior pituitary was detected. CONCLUSIONS: These findings suggest that TRHR type 2 is widely distributed and that the method used is valuable in studying the distribution of TRHR type 2 in rats.

Animals↗
PubMed1998

[Postoperative changes in the coagulation and fibrinolytic systems in endoluminal stent-graft treatment of thoracic aortic aneurysms].

We studied changes in blood coagulation and fibrinolytic system in 18 cases of thoracic aortic aneurysm and 5 cases of aortic dissection treated with stent grafts. The mean operation time was 259 +/- 67 minutes and the amount of blood loss during operation was 472 +/- 456 ml. Although blood transfusion of 220 +/- 360 ml was performed in 7 cases, 16 of 23 cases (70%) received no homologous blood transfusion. Consequently, the endoluminal stent graft treatment was minimally invasive compared with the conventional surgical procedure. On the 1st postoperative day, platelet counts and AT-III decreased and TAT increased. The promotion of blood coagulability was found in these patients on the 1st day after the operation. Changes in the fibrinolytic system were less marked than that in coagulation. These results suggest that the thrombosed aneurysm was excluded from systemic blood flow by the stent graft. There was no consumption coagulopathy in any case with aneurysm excluded by stent graft deployment. Stent-graft treatment for thoracic aortic aneurysm can be successfully performed without consumption coagulopathy when the aneurysm is completely excluded.

Aged↗