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Biomedical subjects

K Sakata

Publications and source records attributed to K Sakata.

At least 145 records · Page 8Linked to original sources
PubMed1999

[Experimental study of water leakage in duraplasty using ePTFE sheet as an artificial dura mater].

The authors have evaluated the preventive effect of water leakage from the suture holes of expanded polytetrafluoroethylene (ePTFE) sheet. Six currently available suture materials (4-0 SURGILON, 4 types of Gore-tex suture, DuraClose) were compared. The water leakage was 0.05 cc/min when using Gore-tex suture (CV-6, needle/thread ratio = 1.0), 0.025 cc/min when using DuraClose. With each two material, the water leakage was significantly less (p < 0.05) in comparison with other materials. Scanning electron microscopic examination revealed that the residual suture holes were minimum when using Gore-tex suture (CV-6, needle/thread ratio = 1.0). In conclusion, running suture with Gore-tex suture (CV-6, needle/thread ratio = 1.0) could be effective in preventing water leakage from the suture holes of ePTFE sheet in duraplasty.

Dura Mater↗
PubMed1999

[Idiopathic pulmonary fibrosis of the upper lobe: a case report].

A 26-year-old man was admitted to our hospital complaining of exertional dyspnea. Chest x-ray films disclosed reticulonodular shadows predominantly in the upper fields of both lungs, but no apical cap. Lung biopsy specimens obtained from the upper lobe by video-assisted thoracoscopy revealed subpleural elasto-fibrosis. Also, specimens obtained from the lower lobes disclosed micro-honeycombing due to peri-lobular fibrosis resembling usual interstitial pneumonia. Although pneumothorax occurred repeatedly, the lungs reinflated on each occasion without artificial intervention. Similar radiographic findings had been obtained on the patient's father, who died of idiopathic pulmonary fibrosis at the age of 56. Idiopathic pulmonary upper lobe fibrosis was conclusively diagnosed because the patient exhibited most of the features originally described by Amitani et al.

Adult↗
PubMed1999

Cardiac sympathetic nervous system in early essential hypertension assessed by 123I-MIBG.

UNLABELLED: Sympathetic overactivity has been noted in various clinical stages of essential hypertension. The purpose of this study is to investigate 123I-metaiodobenzylguanidine (MIBG) uptake and washout in patients with borderline and mild hypertension. METHODS: To assess cardiac sympathetic function in essential hypertension, we performed 123I-MIBG cardiac imaging and echocardiography in 25 normotensive, 25 borderline hypertensive and 24 mildly hypertensive men. Age and body mass index were similar in the three groups. RESULTS: Regarding the echocardiographic variables, the left ventricular mass index (LVMI) was significantly higher in the mildly hypertensive group (125.6+/-28.6 g/m2) than in the normotensive (99.9+/-20.7 g/m2) and the borderline hypertensive (110.0+/-24.4 g/m2) groups (P < 0.001 and P < 0.05, respectively). Regarding the scintigraphic variables, the heart-to-mediastinum (H/M) ratio was significantly lower in the mildly hypertensive group (1.8+/-0.3) than in the normotensive (2.1+/-0.3) and the borderline hypertensive (2.1+/-0.2) groups. In contrast, the washout rate was significantly higher in the mildly hypertensive group (17.6%+/-10.8%) than in the normotensive (7.0%+/-4.9%) and the borderline (11.9%+/-8.9%) hypertensive groups (P< 0.001 and P< 0.02, respectively). In addition, the borderline hypertensive group had a significantly higher washout rate than the normotensive group (P < 0.05). MIBG washout rate had a strong positive correlation with LVMI (r = 0.77, P < 0.0001). In contrast, the H/M ratio had a weak negative correlation with LVMI (r = -0.40, P < 0.0006). CONCLUSION: During the course of establishment of essential hypertension, the washout rate becomes higher with the advance of hypertension and with the development of left ventricular hypertrophy. Thus, we suggest a strong relationship between cardiac sympathetic activity and the advance of hypertension at its early stages.

3-Iodobenzylguanidine↗
PubMed1998

High-dose conformal radiotherapy influenced the pattern of failure but did not improve survival in glioblastoma multiforme.

BACKGROUND AND PURPOSE: Although glioblastoma multiforme is clearly radiation-resistant, there is evidence of a dose-dependent response relationship. The purpose of the study was to evaluate the impact of higher dose by rotational multileaf collimator (MLC) conformal radiation therapy. MATERIALS AND METHODS: From 1984 to 1995, 38 consecutive cases with intracranial glioblastoma multiforme were treated using the rotational MLC conformal therapy. There were 25 men and 13 women with a median age of 47 years (12-73 years, mean 46.5 years). Median Karnofsky performance score was 80 (30-100, mean 78.2). Median tumor volume was 64 cc (8-800 cc, mean 110.3 cc). All underwent surgical intervention (only biopsy in 1, partial resection in 13, subtotal resection in 21, and gross total resection in 3). Radiation dose to was 60 to 80 Gy (median 68.5 Gy, mean 68.3 Gy) in 21 patients treated before 1990 and 90 Gy in the 17 patients thereafter. Biweekly i.v. chemotherapy was also administered for both arms. RESULTS: The 1-year, 2-year, 5-year, and 10-year overall survival rates were 75%, 42%, 20%, and 15%, respectively. Univariate analysis showed the initial tumor volume, residual tumor volume, and Karnofsky performance score were statistically significant factors for survival. Only the residual tumor volume was statistically significant by multivariate analysis. The 5-year survival rate of patients with residual tumors of 5 cc or less in volume was as good as 37%. Survival of the 90-Gy Group appeared inferior to that of the Low-Dose Group, though no statistical difference was seen (the 3-year survival was 40% vs. 22%). Local failure was observed in 16 of the 19 recurrences in the Low-Dose Group, whereas it was observed in only 4 of the 13 recurrences in the 90-Gy Group. The difference in pattern of failure was statistically significant. Two patients of the High-Dose Group developed radiation necrosis and one died of it. CONCLUSIONS: The high-dose conformal radiotherapy did not improve survival in the disease, but did change the pattern of failure.

Adolescent↗
PubMed1998

Evaluation of coronary flow velocity dynamics and flow reserve in patients with Kawasaki disease by means of a Doppler guide wire.

OBJECTIVES: To assess the pathophysiologic effects of the coronary sequelae of Kawasaki disease on coronary hemodynamic variables, we regionally evaluated the flow velocity dynamics and flow reserve in coronary vessels with lesions using an intracoronary Doppler flow guide wire. BACKGROUND: The pathophysiologic effects of the coronary sequelae of Kawasaki disease on coronary hemodynamic variables have not been completely clarified, and we previously reported some discrepancies between coronary angiographic findings and exercise stress tests in Kawasaki disease. METHODS: Doppler phasic coronary flow velocity was determined using an 0.018-in. (0.046-cm) intracoronary Doppler flow guide wire at rest and during the adenosine triphosphate-induced hyperemic response in 95 patients (75 male, 20 female, mean age 9.8+/-6.2 years) with Kawasaki disease. RESULTS: In 25 patients with coronary aneurysms in 29 vessels, the average peak velocity and diastolic to systolic velocity ratio were significantly (p < 0.05) decreased in the moderate-sized and large-sized aneurysms. Significantly lower values in coronary flow reserve (CFR) were noted in 3 of 10 vessels with moderate aneurysms and in 4 of 7 vessels with large aneurysms. A significant positive correlation (y = 0.53x + 14.6, r2 = 0.91) was observed between the percent diameter stenosis evaluated by angiography and that calculated from the flow velocity measurement. However, the percent diameter stenosis calculated from the flow velocity measurement was underestimated compared with that determined by angiography in the stenotic lesions of intermediate severity. A reduced CFR was noted in five of seven vessels with intermediate stenosis ranging from 50% to 75%, and also in three vessels with mild stenosis ranging from 30% to 40%. A reduced CFR was also observed in six of the eight angiographically normal vessels associated with the area of reduced perfusion on exercise thallium-201 myocardial scintigraphy. CONCLUSIONS: Abnormalities in flow dynamics and a reduction in flow reserve were revealed in coronary aneurysms of intermediate to large size and in stenotic lesions, even of mild to intermediate severity, in patients with Kawasaki disease. Abnormalities in the coronary microcirculation, as well as epicardial lesions, contribute to the pathophysiologic responses in Kawasaki disease.

Adolescent↗
PubMed1998

Radiotherapy for Kimura's disease: the optimum dosage.

PURPOSE: To evaluate retrospectively the optimum dosage of irradiation for Kimura's disease. METHODS AND MATERIALS: Twenty patients with Kimura's disease were treated with radiotherapy. The sex ratio was 19 males to 1 female. The mean ages at onset, initial treatment, and radiotherapy were 26.2, 29.5, and 32.2 years, respectively. Radiotherapy was mainly applied for residual or recurrent tumors. The eosinophil count increased by more than 10% in 18 of the 20 patients. In most instances, irradiation was given through a single field with dosages ranging from 20 to 44 Gy. RESULTS: At the completion of radiotherapy, a marked response in tumor size was noted in all cases. The minimum follow-up was 48 months. Local control was obtained in 23 of 31 lesions (74.1%). At dosages of < or =25 Gy, 26-30 Gy, and > 30 Gy, local control was obtained in 2 of 8 (25.0%), 9 of 10 (90.0%), and 12 of 13 sites (92.3%), respectively. CONCLUSIONS: Radiotherapy is an effective treatment for Kimura's disease. This strongly suggests that no surgical procedure other than a biopsy should be carried out. The radiation field should be limited to the lesion and swelling of the adjacent lymph nodes as much as possible, with a optimum dosage of 26-30 Gy regardless of tumor size.

Adolescent↗
PubMed1998

The effect of radiation on the expression of intercellular adhesion molecule-1 of human adenocarcinoma cells.

PURPOSE: To investigate the changes in antigenic expression of intercellular adhesion molecule-1 (ICAM-1) caused by ionizing radiation of cultured human adenocarcinoma cells. METHODS AND MATERIALS: Human colonic BM314 and gastric MKN45 adenocarcinoma cells were irradiated to investigate the expression of ICAM-1 on the cell membrane and in the supernatant. In addition, the ICAM-1 gene expression (mRNA) was analyzed using a ICAM-1 cDNA as a probe. RESULTS: The expression of ICAM-1 on the membrane was found to increase by irradiation. This effect was also observed in the supernatant. In addition, the irradiated cell population showed slight, but clear increases in ICAM-1 mRNA expression. CONCLUSIONS: These results show that the enhancement of expression of ICAM-1 by radiation takes place at the ICAM-1 gene expression (mRNA) level. The results suggest that the low dose radiation may be useful for accumulating LFA-1 positive cytotoxic T lymphocytes (CTL) at the local tumor tissue, by which tumor cells may be attacked.

Adenocarcinoma↗
PubMed1998

NMR Analytical Approach To Clarify the Antioxidative Molecular Mechanism of Catechins Using 1,1-Diphenyl-2-picrylhydrazyl.

Each tea catechin was reacted with 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the reaction mixture was subjected to NMR analysis. The antioxidation mechanism of (+)-catechin [(+)-C] is considered to be due to the change of the B-ring to an o-quinone structure at first because of the appearance of two carbonyl signals. This is substantiated by trapping the compound as an adduct of a 1,2-phenylenediamine to an o-quinone. (-)-Epicatechin [(-)-EC] was also confirmed to give a similar result, but in the case of (-)-epigallocatechin [(-)-EGC] and ethyl gallate (EG) no carbonyl signals were observed. The antioxidation mechanisms of (-)-EGC and EG are different from those of (+)-C and (-)-EC. This may be one of the reasons for the differences of the antioxidative activities between the two types of catechins.

Journal Article↗
PubMed1998

Video-assisted thoracic surgery through a single skin incision.

OBJECTIVE: To develop a minimally invasive video-assisted thoracic surgery technique. DESIGN: Case series. SETTING: University referral center. PATIENTS: Six consecutive patients with a pneumothorax who underwent video-assisted thoracic surgery through a single skin incision. INTERVENTIONS: A flexible digital bronchoscope was placed in a scope guide. A single 2.0-cm skin incision was made in the midaxillary line. The entire lung was carefully explored. An endoscopic stapling device was then inserted, and the lung resection was performed through a single skin incision. PRIMARY OUTCOME MEASURES: Operative time, estimated amount of blood loss, operative complications, and postoperative air leakage were recorded. RESULTS: The video-assisted thoracic surgery procedure through a single incision was successful in all 6 patients. There were no associated complications at 1-year follow-up. CONCLUSIONS: We were able to perform the video-assisted thoracic surgery procedure through a single skin incision using a scope guide and a flexible scope that enables visualization of the entire pleural cavity, providing even laser ablation. This new technique can be used to treat patients with pneumothoraces without the need for additional skin incisions.

Adult↗
PubMed1998

Infrequent frameshift mutations of polynucleotide repeats in multiple primary cancers affecting the esophagus and other organs.

Frequent frameshift mutations of simple nucleotide repeats in the protein-encoding regions, as well as replication errors (RERs) at microsatellite loci, have recently been demonstrated in gastrointestinal tumors. These genetic instabilities have been considered indicative of an increased risk of accumulating mutations in cancer-associated genes and of developing multiple cancers. We studied frameshift (or insertion/deletion) mutations of simple nucleotide repeats in five genes (TGFbeta type II receptor [TGFbetaRII], E2F4, MSH2, MSH3, and MSH6) in 23 tumors from 12 patients who had synchronous cancers of the esophagus and other organs. Genetic instability at four microsatellite loci, as well as mutations in the TP53, APC, and KRAS2 genes, were also studied. No frameshift mutations were observed in the TGFbetaRII, MSH3, and MSH6 genes. RER and a deletion mutation of BAT26 in MSH2 were present in one (1/23; 4%) gastric cancer. This tumor also carried a deletion mutation in the serine (AGC) repeat of the E2F4 gene. Mutation screening of the TP53, APC, and KRAS2 genes revealed that the synchronous cancers did not carry the same mutations. Our results suggested that genetic instability, such as insertion/deletion mutations in simple nucleotide repeats, is not significantly associated with the development of multiple primary cancers of the esophagus and other organs, and that these synchronous cancers developed independently according to their different environmental factors.

Colonic Neoplasms↗
PubMed1998

Treatment of localized non-Hodgkin's lymphomas of the head and neck: focusing on cases of non-lethal midline granuloma.

This report clarifies the prognostic factors for survival in localized non-Hodgkin's lymphoma (NHL) of the head and neck and defines optimal regimens for this disease. One hundred-seven untreated patients with Stage I or II NHL of the head and neck were treated with involved field radiation therapy for orbital, nasal, or paranasal lymphoma and extended field radiation for Waldeyer's ring or neck lymphoma. Radiation doses were 39-48 Gy. In the latter half of the study, adjuvant chemotherapy was administered. Of 107 patients, 95 achieved complete response (CR). Of the 12 patients that did not achieve CR, 9 had nasal T-cell lymphoma (NTL) of the lethal midline granuloma type (LMG-NTL). Only one patient who obtained CR relapsed in a previously irradiated area. Age, sex, stage, bulky mass, number of involved sites, LMG-NTL, histologic subtypes, radiation dose, and adriamycin dose were analyzed for prognostic significance for disease-specific survival in NHL by multivariate analysis. LMG-NTL was the most significant prognostic factor (P < 0.001). Patients with higher age also experienced a higher relative risk than patients of > or =60 years of age (P = 0.0063). Dose of adriamycin reached the borderline significance (P = 0.0600). Radiotherapy is excellent for obtaining local control of head and neck NHL. Randomized trials are required to determine the appropriate radiation field and dose in patients previously treated with chemotherapy. LMG-NTL and age were the significant prognostic factors for disease-specific survival.

Adolescent↗
PubMed1998

Fas (CD95)-transduced signal preferentially stimulates lupus peripheral T lymphocytes.

Fas (CD95) is a cell surface receptor whose biological function in circulating peripheral T cells is not well understood. To address the question of abnormal T cell sensitivity to Fas stimulation in systemic lupus erythematosus (SLE), we studied Fas-transduced stimulation and apoptosis in peripheral blood T cells from patients with SLE and normal control. Immobilized anti-Fas monoclonal antibodies (mAb) (imCH-11; IgM type) significantly stimulated SLE T cell proliferation compared to T cells from normal donors and patients with rheumatoid arthritis (p < 0.003 and p < 0.005, respectively). The soluble form of CH-11 and other immobilized anti-Fas mAb (UB-2, ZB-4; IgG type) failed to stimulate lupus T cells while immobilized human Fas ligand did. Furthermore, imCH-11 induced IL-2 and IL-6 mRNA expression. However, imCH-11 activation failed to induce expression of the T cell activation surface molecules CD25 and CD69. Addition of exogenous ceramide, a second messenger for Fas-mediated apoptosis signaling, also induced T cell proliferation in SLE and normal controls. Moreover, fumonisin B1, a specific ceramide synthase inhibitor, and caspase inhibitors markedly suppressed imCH-11 induced T cell proliferation, suggesting that the ceramide pathway may be involved in Fas-transduced stimulation signals in SLE T cells. These results show that SLE T cells have an alteration in the Fas signal transduction pathway leading to cell proliferation. This defect may be important in Fas-mediated peripheral immune homeostasis.

Adult↗
PubMed1998

Right-sided pedunculated hepatocellular carcinoma: a form of adrenal metastasis.

Pedunculated hepatocellular carcinoma (HCC) or extrahepatic growth of HC C is an uncommon but not rare pathological form, but its genesis is unknown. Right-sided adrenal metastases of HCC that were abutting on or about to fuse with the right hepatic lobe were resected in three patients. The masses seemed to have originated in the para-adrenal tissue, leaving the adrenal gland intact. They were partially supplied by the hepatic artery as well as by the suprarenal artery. Four cases of autopsied pedunculated HCC of the right lobe were also studied. The mass was protruding caudad from the noncancerous parenchyma of the right lobe. Postmortem angiography carried out on one liver showed that only a small portion of the mass toward the liver was supplied from the hepatic artery. These observations suggest that some, perhaps most, of the right-sided pedunculated HCCs represent fusion of the right lobe and para-adrenal or adrenal metastatic HCC. This phenomenon may be explained by possible transport of cancer cells toward the right adrenal gland through the so-called adrenohepatic fusion, a relatively common anatomical change in advanced age.

Adrenal Gland Neoplasms↗
PubMed1998

Radiotherapy of bone metastases of a spinal meningeal hemangiopericytoma.

Hemangiopericytoma is a rare tumor arising from pericapillary cells or pericytes of Zimmerman, and can occur anywhere capillaries are found. We describe a patient with a meningeal hemangiopericytoma who was treated with primary surgical resection and experienced multiple bone metastases 20 years after the first treatment. This patient with multiple bone metastases was treated with multiple courses of irradiation and good palliation was achieved.

Adult↗
PubMed1998

Determinants of bone loss in a rural Japanese community: the Taiji Study.

The objective of this study was to assess the rate of bone loss and characterize its determinants, among the inhabitants of Taiji, a rural Japanese community. A cohort of 2261 inhabitants aged 40-79 years was established using resident registration in 1992. Fifty men and 50 women in each of four age strata between 40 and 79 years were randomly selected and completed a self-administered risk factor questionnaire. Baseline bone density of lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry in 1993. BMD was measured again on the same participants in 1996. The rates of change of lumbar spine BMD in men in their 40s, 50s, 60s and 70s were 0.20%, 0.34%, 0.43% and 0.28% respectively. Rates in women were -0.35%, -1.02%, -0.10% and -0.20% respectively. At the femoral neck, rates of change in BMD among men in their 40s, 50s, 60s and 70s were 0.09%, -0.07%, 0.34% and 0.31% respectively. Femoral neck rates of change among women were -0.55%, 0.02%, 0.49% and -0.25% respectively. The rate of change of lumbar spine BMD was -0.24% in premenopausal women with regular periods, -1.99% in premenopausal women with irregular periods and -0.33% in postmenopausal women. Anthropometric measurements at baseline were also related significantly to change in bone density. Baseline weight and height were statistically significant predictors of bone loss rate. These data provide estimates of the rate of bone loss among Japanese men and women aged 40-79 years. They suggest that body build and menstrual function in women are important determinants of bone loss.

Adult↗
PubMed1998

Molecular analysis of the androgen receptor gene in 4 patients with complete androgen insensitivity.

Androgen insensitivity syndromes are due to defects in the androgen receptor gene. In this study, we analyzed the androgen receptor gene in four cases with complete androgen insensitivity syndrome. In patient 1, one substitutional mutation [arginine (codon CGC) to cysteine (codon TGC) at position 774] of exon F was identified. This position was located in the hormone binding domain and appeared to be one hot spot of mutations because the mutations at the same position in several unrelated cases were reported before. In patient 2, one substitutional mutation [tyrosine (codon TAT) to cysteine (codon TGT) at position 571] of exon B was identified. This position was located in the DNA binding domain. In patients 3 and 4 (siblings), one substitutional mutation [arginine (codon CGA) to glutamine (codon CAA) at position 752] of exon E was identified. Taken together, these abnormalities might be related to the pathogenesis of complete androgen insensitivity.

Adolescent↗