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Biomedical subjects

K Oyama

Publications and source records attributed to K Oyama.

At least 37 records · Page 2Linked to original sources
PubMed2002

[Total aortic arch replacement for distal aortic arch aneurysm with adhered left lung: report of a case].

A 76-year-old man with a history of pleuritis and a cerebral infarct underwent a total arch replacement for an aneurysm of the distal aortic arch. Computed tomography revealed a true aneurysm having a maximum diameter of 70 mm as well as pleural thickening and calcification. Total arch replacement with selective cerebral perfusion was performed through median sternotomy and left thoracotomy. The myocardial ischemic time was shortened by reperfusion from the right axillary artery after the anastomosis of the proximal ascending aorta and the brachiocephalic artery. After the other branches of the arch were anastomosed, a distal anastomosis through the left thoracotomy was then performed using the pull-through method, enabling minimal decortication of the adhered lung. Our surgical procedure for distal arch aneurysm with adhered lung involves the addition of a left thoracotomy, but the reduction in the myocardial ischemic time and lung injury are of benefit.

Aged↗
PubMed2002

[Corrective surgery for pectus excavatum in patients with Marfan syndrome].

OBJECTIVE: Among 1,967 patients who underwent corrective surgery for pectus excavatum in our department between January 1980 and December 2001, 33 patients diagnosed as having Marfan syndrome were evaluated. We evaluated the clinical problems and outcome of the 33 patients. RESULTS: The outcome of corrective surgery for pectus excavatum in the 26 patients who underwent a single technique surgery was generally good. Pectus excavatum was complicated by a total of 25 cases of cardiovascular disorder in 14 of 33 (42%) patients. Six patients underwent corrective surgery for pectus excavatum and cardiovascular disorders simultaneously. Three patients also had disorders of lung, which included spontaneous pneumothorax in 2 patients and progressive emphysematous cyst in 1 patient. The 2 patients with spontaneous pneumothorax underwent resection of bullae together with corrective surgery of pectus excavatum, while the patient with progressive emphysematous cyst underwent resection of bullae in a separate surgery after correction of pectus excavatum. Cardiovascular disorders were aggravated in 6 of the 20 patients who could be follow up. A total of 4 (20%) patients died long after surgery. CONCLUSIONS: We corrected pectus excavatum in 33 patients with Marfan syndrome, and obtained favorable outcomes. The postsurgical outcome depends on progression of lesions of the heart and large vessels, and it is essential to monitor such lesions carefully.

Adolescent↗
PubMed2001

Thoracoscopic surgery for pneumothorax in older patients.

BACKGROUND: Secondary pneumothorax is more common in older pneumothorax patients. Therefore, we set out to investigate the usefulness of thoracoscopic surgery in this group. METHODS: A total of 59 operations were performed on patients aged > or = 50 years, with the goal of excising only the lesions responsible for air leaks by using the minimum degree of dissection. If the patients were found to have numerous bullae, the lesions responsible were identified by pleurography. The duration of chest tube drainage, hospital stay, and recurrence were assessed. RESULTS: The air leaks stopped and all patients were discharged without drains. Postoperative drainage time was 3.8 +/- 3.0 days. Postoperative hospital stay was 10.8 +/- 9.2 days. Six patients died of other diseases, but there was only one recurrence of pneumothorax. CONCLUSION: We consider video-assisted thoracic surgery (VATS), with the goal of excising only the lesions responsible for air leaks, to be particularly efficacious in older pneumothorax patients.

Aged↗
PubMed2001

Observation of a (6)(LambdaLambda)He double hypernucleus.

A double-hyperfragment event has been found in a hybrid-emulsion experiment. It is identified uniquely as the sequential decay of ( 6)(LambdaLambda)He emitted from a Xi(-) hyperon nuclear capture at rest. The mass of ( 6)(LambdaLambda)He and the Lambda-Lambda interaction energy DeltaB(LambdaLambda) have been measured for the first time devoid of the ambiguities due to the possibilities of excited states. The value of DeltaB(LambdaLambda) is 1.01+/-0.20(+0.18)(-0.11) MeV. This demonstrates that the Lambda-Lambda interaction is weakly attractive.

Journal Article↗
PubMed2001

Combination therapy with transcatheter arterial chemoembolization and percutaneous ethanol injection compared with percutaneous ethanol injection alone for patients with small hepatocellular carcinoma: a randomized control study.

BACKGROUND: To assess whether the effectiveness of a combination of transcatheter arterial chemoembolization (TACE) and percutaneous ethanol injection (PEI) is superior to PEI alone in the treatment of patients with small hepatocellular carcinoma (HCC), a randomized controlled study was performed. METHODS: Fifty-two patients with one to three HCC tumors measuring < than 3 cm in greatest dimension were enrolled and underwent the combination TACE-PEI therapy (26 patients with 31 nodules) or PEI alone (26 patients with 34 nodules). There were no significant differences in background between the two groups. The mean follow-up was 30.1 months +/- 17.5 months. RESULTS: The cumulative detection rates of local residual disease in the TACE-PEI group (3.7% at 1 year and 19.3% at 3 years) were significantly lower compared with the detection rates in the PEI alone group (34.2% and 39.3%, respectively; P = 0.013). The cumulative new nodular recurrence rates in the TACE-PEI group (8.7% at 1 year and 19.3% at 3 years) tended to be lower compared with the recurrence rates in the PEI alone group (26.9% and 80.1%, respectively; P = 0.057). The cumulative survival rates were not significantly different between the two groups (TACE-PEI group: 100%, 80.8%, and 40.4% at 1 year, 3 years, and 5 years, respectively; PEI alone group: 91.3%, 65.9%, and 37.7%, respectively; P = 0.458). However, among the patients from each group with HCC tumors measuring < 2 cm, the survival rates in the TACE-PEI group were improved compared with the survival rates in the PEI alone group (P < 0.01) in addition to the detection rates of local residual disease and the new nodular recurrence rates (P < 0.01 and P = 0.047, respectively). The frequency of short-term and long-term adverse effects was not significantly different between the groups. However, only two major complications (biloma and ascites with pleural effusion) were observed, both of which occurred in patients in the TACE-PEI group. CONCLUSIONS: Combination therapy with TACE-PEI was superior to PEI alone in the treatment of patients with small HCC tumors, especially for patients with HCC tumors measuring < 2 cm in greatest dimension.

Aged↗
PubMed2001

Bullectomy is beneficial in the pulmonary blood flow/driving pressure relationship in bullous emphysema patients.

OBJECTIVES: Few physiological studies have been on pulmonary circulation, including the relationship between pulmonary blood flow and driving pressure, and viscosity changes arising from hematocrit changes before versus after lung volume reduction Surgery or bullectomy in emphysematous patients. METHODS: We studied the relationship between pulmonary blood flow and driving pressure before and after bullectomy using a unilateral pulmonary artery occlusion test based on pulmonary blood flow fractions obtained by pulmonary blood flow scintigraphy in 7 patients with pulmonary emphysema associated with bullae. RESULTS: Among the 7 undergoing bullectomy, the pulmonary blood flow/driving pressure relationship decreased in 5 and was unchanged in 2. Of the 11 lungs treated by bullectomy, this relationship decreased in 8 lungs, but not 3 (p < 0.01). No significant difference was seen in oxygen partial pressure in arterial and mixed venous blood or hematocrit. CONCLUSION: We concluded that bullectomy shifted the pulmonary blood flow/driving pressure relationship downword in some cases with significant bullae.

Aged↗
PubMed2001

Nitinol stent for the treatment of tracheobronchial stenosis.

OBJECTIVE: The purpose of this study was to evaluate the potential utility of implantation of a nickel-titanium alloy (nitinol) stent for the treatment of malignant or benign tracheobronchial stenosis. METHODS: We evaluated 18 patients (14 men and 4 women) who received 24 nitinol stents, between November 1997 and May 2000. All 18 patients had severe dyspnea caused by tracheobronchial stenosis. The underlying condition was malignant disease in 15 patients, and benign tracheal collapse in the other 3 patients. RESULTS: Implantation of the stent was successfully performed in all patients. Seventeen patients experienced immediate clinical improvement in respiratory symptoms. The remaining 1 patient with a bronchial fistule after lobectomy did not benefit, and died of pneumonia at 16 days after the implantation. In 15 patients, the procedure was performed using a flexible bronchoscope under local anesthesia alone, while the remaining 3 patients needed intravenous sedation. There was no complication resulting from the stent implantation. Among the 3 patients with benign tracheal collapse, 2 patients were alive at 746 and at 401 days after the stent implantation, at the time of this report. One patient with cicatricial stenosis after intubation died of heart failure due to previous myocardial infarction. Among the 15 patients with malignant disease, 4 patients have survived for 177 to 305 days to date, while the other 11 patients have died of primary malignancy with a mean survival duration of 60.2 days. CONCLUSION: The nitinol stent was effective in treating malignant or benign tracheobronchial stenosis, and had some remarkable advantages compared with other tracheobronchial stents. In stenting, most procedures can be performed using flexible bronchoscope under local anesthesia.

Adult↗
PubMed2001

Wallstent endovascular prosthesis for the treatment of superior vena cava syndrome.

OBJECTIVE: We assessed the clinical outcome of self-expanding Wallstent endovascular prosthesis in the treatment of superior vena cava syndrome due to malignant tumors. METHODS: Eleven patients with malignant superior vena cava syndrome were treated by percutaneous implantation of the self-expanding Wallstent endovascular prosthesis across the stricture site. Patency was defined by the absence of symptoms and signs of superior vena cava syndrome. RESULTS: Ten of the 11 experienced complete symptomatic relief within 3 days of stent implantation. The remaining 1 did not benefit, and required a second procedure, dying of heart failure 5 days after stent implantation. Ten patients remain symptomatically free of superior vena cava syndrome to date or until death in follow-up lasting 17 to 227 days. CONCLUSION: Implantation of the self-expanding Wallstent endovascular prosthesis for malignant superior vena cava syndrome provides rapid symptomatic relief and improves the patient's quality of life.

Adult↗
PubMed2001

Inclusion body myositis associated with hepatitis C virus infection.

The case of a 77-year-old woman with hepatitis C virus infection with a 5-year history of muscle weakness and mild disturbance of gait is reported. Steroid therapy did not improve her symptoms. She developed HCV-related liver cirrhosis and hepatocellular carcinoma, and muscle biopsy revealed inclusion body myositis. Immunohistochemistry showed that the nonstructural region of HCV and 8-hydroxy-2'-deoxyguanosine, a marker of DNA damage by reactive oxygen species, were present in striated muscle cells of this patient.

Aged↗
PubMed2001

Expression of interleukin-6, interleukin-6 receptor (gp80), and the receptor's signal-transducing subunit (gp130) in human normal pituitary glands and pituitary adenomas.

Interleukin-6 (IL-6) is an important cytokine in cell proliferation and differentiation in several organs. It has also been reported that IL-6 plays a role in secretion or release of pituitary hormones in pituitary hormone-secreting cells and pituitary adenomas, but convincing data in situ have not yet been reported. In this study, we examined the participation of IL-6 in the production of pituitary hormones and the differences between human normal pituitary glands and pituitary adenomas by determination of the localization or expression of IL-6, IL-6 receptor (IL-6R, gp80), and the signal-transducing subunit (gp130) of the receptor using immunohistochemical staining and RT-PCR. IL-6 was mainly expressed in ACTH- and FSH/LH-secreting cells in normal pituitary glands, as shown by double staining. gp 80 and gp130 were coexpressed in almost all GH- and PRL-secreting cells and in approximately 30% of FSH/LH-secreting cells. RT-PCR showed that IL-6 mRNA was expressed in only one of all the pituitary adenomas examined, whereas gp 80 and gp 130 mRNAs were detected in all these pituitary adenomas. In conclusion, IL-6 was mainly expressed in ACTH- and FSH/LH-secreting cells, and the receptors were expressed in GH-, PRL- and FSH/LH-secreting cells in human normal pituitary glands. Furthermore, our data emphasized that the mechanism of IL-6 function in human pituitary adenoma cells is distinct from that in normal pituitary cells.

Adenoma↗
PubMed2001

Expression of neuro D1 in human normal pituitaries and pituitary adenomas.

Neuro D1 is a basic helix-loop-helix transcription factor expressed in the endocrine cells of pancreas and in a subset of neurons as they undergo terminal differentiation. In the adult pituitary gland, Neuro D1 is expressed in corticotroph cells and contributes to the corticotroph-specific pro-opiomelanocortin (POMC) transcription by interacting with Pituitary homeobox 1 (Ptx 1) transcription factor. In the present study, we investigated the expression of Neuro D1 in human normal pituitaries and different types of human pituitary adenomas using the RT-PCR and immunohistochemical techniques. Using RT-PCR, Neuro D1 mRNA was found to be expressed in ACTH-secreting adenomas (n = 3) and 6 of 8 non-functioning adenomas. On the other hand, GH-secreting adenomas (n = 5) and PRL-secreting adenomas (n = 3) were completely negative for Neuro D1 mRNA. Immunohistochemically, Neuro D1 was expressed in all ACTH-secreting adenomas (n = 10), and in 14 of 20 nonfunctioning adenomas. In contrast, 3 of 10 PRL-secreting adenomas and 2 of 10 GH-secreting adenomas showed positive Neuro D1 staining in the nuclei. The above results suggest that Neuro D1 contribute to the functional expression and the differentiation of ACTH-secreting adenomas. It also appears from our study that Neuro D1 might play a role in the differentiation of non-functioning adenomas, the mechanism of which remains to be further investigated. This is the first study on Neuro D1 in case of human pituitary adenomas.

Adenoma↗
PubMed2001

Immunohistochemical analysis of RCAS1 in human pituitary adenomas.

It has been reported that RCAS1 (receptor-binding cancer antigen expressed on SiSO cells) acts as a ligand for a receptor present on normal peripheral lymphocytes and induces apoptotic cell death. It is expressed in uterine and ovarian carcinomas, especially in invasive cancers. This immunohistochemical study is aimed to elucidate the expression of RCAS1 in human pituitary adenomas in order to clarify its role in their proliferative regulation and invasiveness. Five normal pituitary glands, 50 human pituitary adenomas, and one malignant glioma were subjected to immunohistochemical studies. In normal pituitary glands, immunostaining of RCAS1 and MIB-1 was not found. In malignant glioma, large numbers of cell nuclei were positive for MIB-1 (MIB-1 index: 28%), and RCAS1 was detected both in the cytoplasm and on the membrane of the tumor cells. Expression of RCAS1 was noted in 48% of pituitary adenomas immunohistochemically (60.0% of growth hormone-secreting adenomas, 60.0% of prolactin-secreting adenomas, 42.9% of adrenocorticotrophin-secreting adenomas, 40.0% of thyroid-stimulating hormone-secreting adenomas, 33.3% of nonfunctioning adenomas, and 44.4% of gonadotropin-subunit-positive adenomas). It showed no correlation with tumor type, size, and invasiveness. The statistically significant relationship between RCAS1 and MIB-1 positivity was identified in our study. These results suggest that expression of RCAS1 as well as MIB-1 positivity predict the growth potential of individual pituitary adenomas.

Adenoma↗
PubMed2000

In vivo transfer of hepatocyte growth factor gene accelerates proliferation of hepatic oval cells in a 2-acetylaminofluorene/partial hepatectomy model in rats.

To clarify the effect of hepatocyte growth factor (HGF) on proliferation of hepatic oval cells, we transferred HGF gene into liver of the Solt-Farber rat model. Male Fisher 344 rats were infected with a recombinant adenovirus carrying the cDNA for HGF (pAxCAHGF) from tail vein. HGF mRNA showed its peak at 4 days, and diminished thereafter. The total and proliferating cell nuclear antigen-positive hepatic oval cells were significantly elevated in HGF-transferred rats, in which stem cell factor and c-kit mRNA increased at each time point. Our results suggest that in vivo transfer of the HGF gene into liver accelerates proliferation of hepatic oval cells in the Solt-Farber model in rats.

2-Acetylaminofluorene↗
PubMed2000

Aspiration cytology and core biopsy of a carcinoid tumor arising in a retrorectal cyst: a case report.

Retrorectal cysts are uncommon lesions of uncertain histogenesis, and primary carcinoid tumors arising in retrorectal cysts are extremely rare. We present the case of a 52-yr-old man who had a 22-cm partially cystic, partially solid mass in the presacral space. A computed tomography-guided fine-needle aspiration of the mass was performed. The smears contained abundant keratinous debris and rare groups of tumor cells. The tumor cells were cuboidal, with slightly granular cytoplasm and centrally located nuclei with speckled chromatin and inconspicuous nucleoli. Immunocytochemical analysis revealed strong reactivity for chromogranin and keratin, and focal reactivity for synaptophysin and neuron-specific enolase. The cytological diagnosis of a carcinoid arising in a tail-gut cyst was confirmed histologically. This is the first reported case of a carcinoid arising in a retrorectal cyst diagnosed preoperatively by cytology. This diagnosis is possible in the setting of consistent clinical, radiographic, and cytological findings.

Biomarkers, Tumor↗
PubMed2000

Occult hepatitis B virus infection in HBs antigen-negative hepatocellular carcinoma in a Japanese population: involvement of HBx and p53.

Hepatitis B virus (HBV) genome was reported to be detected in serum or liver tissues in hepatocellular carcinoma (HCC) patients negative for hepatitis B surface antigen (HBsAg). Hepatitis B x (HBx) and p53 protein were reported to play an important role in HBV-related hepatocarcinogenesis. To clarify latent HBV infection in HBsAg- and anti-hepatitis C virus (anti-HCV)-negative HCC in a Japanese population and involvement of HBx and p53 protein in these patients, we performed the sensitive and specific nested polymerase chain reaction (PCR) and immunohistochemical analysis. Of 1,024 HCC patients we saw between 1974 and 1998, 66 (6.4%) were negative for HBsAg and anti-HCV. Serum DNA was amplified by nested PCR by using specific primers of surface (S), core (C) and X regions in 26 patients negative for HBsAg and anti-HCV. Eighteen (69%) patients were positive for either S, C, or X region and the results of PCR were confirmed by Southern blotting. Of 18 PCR-positive patients, 3 were positive for anti-HBs and 9 were positive for anti-HBc, however, one was negative for any HBV markers. In HBsAg-negative and PCR-positive patients, the positive rates of expression of HBx and p53 were 8/13 (62%) and 7/13 (54%), being comparable to those in HBsAg-positive HCC patients. The results of the present study suggest that high prevalence of HBV infection is observed in HBsAg-negative HCC in a Japanese population and expression of HBx and p53 is consistent with a role, in these patients, for the transforming ability of these proteins.

Aged↗
PubMed2000

Combined thoracic aortic or upper digestive tract resection for lung cancer and malignant mediastinal tumor.

OBJECTIVE: We studied possible indications and combined resection in patients with lung cancer and mediastinal tumors requiring combined thoracic aortic or upper digestive tract resection. METHODS: Ten patients with lung cancer and malignant mediastinal tumors (9 men and 1 woman aged 39 to 72 years; mean: 60.5) underwent combined aortic or upper digestive tract resection. RESULTS: Five--3 [corrected] with primary lung cancer, 1 with thymic cancer, and 1 with liposarcoma--, underwent combined aortic resection. In 2 each, lung cancer and malignant mediastinal tumor had infiltrated the thoracic aorta. The remaining case of lung cancer was complicated by aortic aneurysm in the distal arch. Cardiopulmonary bypass was conducted in 4, and selective cerebral perfusion in 2. Three patients are alive after 11, 22, and 61 months without disease recurrence. Those undergoing combined upper digestive tract resection all had lung cancer, with 4 having tumors infiltrating the esophagus or corpus ventriculi. The remaining patient had both lung and esophageal cancer. The patient treated with combined corpus ventriculi resection has survived 24 months and the patient treated with combined esophageal resection has survived 12 months without disease recurrence. The 1-year survival rate was 60%, 2-year 23%, and 3-year 23%. Prognosis was generally poor with the longest survival 13 months with N2 lung cancer. CONCLUSIONS: In combined resection due to malignant mediastinal tumor, T4N0-1 lung cancer, or diseases such as aortic aneurysm, prognosis can be expected to improve. Despite the often poor prognosis in T4N2 lung cancer, surgical intervention may be indicated to avoid complications due to tumor invasion and to lengthen survival and improve quality of life.

Adult↗