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Biomedical subjects

K Sakata

Publications and source records attributed to K Sakata.

At least 253 records · Page 14Linked to original sources
PubMed1995

Linkage of the athymic nude locus with the myeloperoxidase locus in the rat.

In rats of the BUF/Mna strain epithelial thymoma development is regulated by a single autosomal susceptible gene, Tsr-1. In pre-thymoma stage, BUF/Mna rats have extremely large thymuses, when compared with those of other strains of rats. The large thymus size of this strain is contributed by a thymus-enlargement gene, Ten-1. On the other hand, reduced thymus size and suppression of thymoma development were found in heterozygous BUF/Mna-rnu/+ rats. Linkage studies between RNU and microsatellite and restriction fragment length polymorphism markers in ([BUF/Mna-rnu/rnu x WKY/NCrj] F1 x WKY/NCrj)- and (WKY/NCrj x [BUF/Mna-rnu/rnu x WKY/NCrj] F1)- backcross rats have led to the localization of RNU on chromosome 10. The rat homolog of mouse Mpo (myeloperoxidase) was also assigned to the chromosome 10. The gene order on the chromosome was MYHSE (myosin heavy chain of embryonic skeletal muscle)--(1.0 centimorgan [cM])--SHBG (sex hormone-binding globulin)--(4.0 cM)--RNU (Rowett rat nude)--(10.0 cM)--MPO--(13.0 cM)--AEP (anion exchange protein). Conserved linkage of homologous loci mapped to rat chromosome 10 and mouse chromosome 11 supports the hypothesis that the RNU and MPO loci are rat homologs of the mouse nu and Mpo loci.

Animals↗
PubMed1995

Iv gamma globulin treatment of Kawasaki disease in Japan: results of a nationwide survey.

The administration of i.v. gamma globulin (IVGG) for Kawasaki disease was investigated throughout Japan in 1993 by obtaining information from the pediatric departments of 2652 hospitals with more than 100 beds. A total of 1826 hospitals (68.9%) responded, reporting on 11,221 patients who were diagnosed during the survey period from January 1991 to December 1992. There were 8958 patients (79.8%) who received IVGG treatment. The most common treatment modality was 200 mg/kg (29.6%), followed by 400 mg/kg (18.7%) and 300 mg/kg (12.9%), all for 5 days. The distributions of total dose were: 1000 mg/kg or less, 45.7%; 1001-1500 mg/kg, 27.3%; and over 1500 mg/kg, 23.8%. For all patients to whom IVGG was administered, treatment was started in 53.8% by day 5 of illness and in 86.1% by day 7. The proportion of those with cardiac sequelae was higher in patients who were treated with IVGG, possibly due to the fact that those who were more severely affected were more likely to be treated with IVGG.

Age Factors↗
PubMed1995

Effect of Kawasaki disease on migration of human umbilical vein endothelial cells.

Kawasaki disease, which is characterized by systemic vasculitis causing coronary arterial involvement in childhood, shows a variety of immunoregulatory abnormalities. Especially the direct or indirect deleterious effects on endothelial cells of cytokines and anti-endothelial cell antibodies (AECA) are considered to be involved in the mechanism responsible for production of vasculitis. Intravenous administration of high doses of gamma-globulin (IVGG) has been used as an effective therapy for Kawasaki disease. To examine the behavior of endothelial cells affected by cytokines and IVGG in Kawasaki disease, we studied the effects of interferon (IFN), IL-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha on the migration of human umbilical vein endothelial cell line (tHUE01) by a modified Boyden chamber method. Plasma from patients with acute Kawasaki disease markedly enhanced the migration of tHUE01 cells. Cytokines, with the exception of TNF-alpha, also enhanced the migration of tHUE01 cells in a dose-dependent manner. Anti-IFN antibody inhibited the migratory activity in response to not only IFN-gamma but also to the plasma from patients with Kawasaki disease. Rabbit AECA (rAECA) also significantly stimulated the migration of tHUE01 cells. Plasma from patients treated with IVGG did not affect the migration of tHUE01 cells. Addition of gamma-globulin significantly inhibited the migration of tHUE01 cells induced by the cytokines or rAECA. These results suggest that cytokines and AECA are important in restructuring and destroying vessel walls in Kawasaki disease by enhancing the migration of endothelial cells, and that IVGG may be therapeutically effective for this disease by suppressing this endothelial cell migration.

Animals↗
PubMed1995

Stimulation of cyclic AMP formation by pituitary adenylate cyclase-activating polypeptide is attenuated by glutamate in rat brain slices.

In rat hippocampal slices, pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) stimulated cyclic AMP formation in dose- and time-dependent manners. The PACAP-38 action was dose-dependently attenuated by L-glutamate in the hippocampus; L-glutamate at the concentration of 1 mM attenuated PACAP-38-stimulated cyclic AMP formation by approximately 30%. The inhibitory effect of L-glutamate is also observed in rat cerebellar slices. In contrast, the inhibitory effect of a prostanoid EP3-receptor agonist on PACAP-38-stimulated cyclic AMP formation was brain region-specific; the inhibitory action was observed in the cerebellum but not in the hippocampus.

Adenylyl Cyclases↗
PubMed1995

Further application and evaluation of critical cell number and modifying factors in radiocurability of multicellular spheroids.

Relationship of cure and surviving clonogenic cell number after various doses of X-irradiation was examined in multicellular spheroids of LCT1 human lung adenocarcinoma cells, LCT2 human lung small cell carcinoma cells and FSA1233 mouse fibrosarcoma cells. Some of these spheroids were cured at such doses that considerable number of clonogenic cells still survived after irradiation. Radiocurability was analyzed by comparing total clonogenic cell number in spheroids, cellular radiosensitivity and critical cell number Nc, i.e., the minimum number of clonogenic cells required to produce regrowth. (Nc-1) cells were killed by post-radiation processes and the larger the critical cell number, the more radiocurable. The LCT2 spheroids had the largest critical cell number and were most radiocurable. To investigate underlying mechanisms, modifying effect of heavily irradiated (HIR) tumor cells on the clonogenicity, i.e., plating efficiency of unirradiated tumor cells was investigated. Plating efficiencies with HIR cells showed significant decrease in LCT2 cells, no change in LCT1 cells and increase in FSA1233 cells. The results indicated that in case of LCT2 spheroids some of viable cells surrounded by dying or dead cells might have been killed with unknown toxic effect additional to direct irradiation effect. Thus, critical cell number analysis may be useful to quantify and to compare modifying effect of cellular/environmental factors in curing process of spheroids or tumors.

Adenocarcinoma↗
PubMed1995

Glycosidic aroma precursors of 2-phenylethyl and benzyl alcohols from Jasminum sambac flowers.

Benzyl 6-O-beta-D-xylopyranosyl-beta-D-glucopyranoside (beta-primeveroside) (1), 2-phenylethyl beta-primeveroside (2), and 2-phenylethyl 6-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranoside (beta-rutinoside) (3) were isolated as aroma precursors of benzyl alcohol and 2-phenylethanol from flower buds of Jasminum sambac Ait. The isolation was guided by an enzymatic hydrolysis and GC and GC-MS analyses.

Benzyl Alcohol↗
PubMed1995

[Coronary artery bypass grafting for a patient with left ventricular ejection fraction of 16%: a case report and review of the Japanese literature].

A 65-year-old man with left ventricular ejection fraction (LVEF) of 16% successfully underwent coronary artery bypass grafting (CABG). CABG used to be contraindicative for patients with LVEF below 20%. However, such patients are recently involved to indication of CABG if viability of the myocardium is proved. We consider CABG is indicated for a patient who keeps a sufficient cardiac output despite a low level of LVEF. Intraaortic balloon pumping which was started immediately after the induction of anesthesia was effective. Only eight patients with LVEF below 20% have undergone CABG in Japan. Thus, we reported our patient with some discussion on operative indication and perioperative management.

Aged↗
PubMed1995

Changes in platelet kinetics after a partial splenic arterial embolization in cirrhotic patients with hypersplenism.

We performed a partial splenic arterial embolization in 22 patients with cirrhosis associated with thrombocytopenia and then evaluated the changes in platelet kinetics after undergoing the procedure using 111In-tropolone-labeled platelets. The controls consisted of eight chronic hepatitis patients who showed a normal platelet count and normal spleen size. The mean splenic infarction ratio after the procedure was 54.9%. A platelet kinetics study was performed before and 2 months after the procedure. Before the procedure, the cirrhotic patients showed increases in the splenic volume and the spleen/liver uptake ratio of the 111In-labeled platelets on both the third and seventh days, and a decrease in the platelet recovery compared with the controls, which suggested an increased platelet pool in the spleen. In addition, the platelet survival time in cirrhotic patients was shortened, whereas the platelet-associated immunoglobulin G (PA-IgG) was higher than that of the controls, which suggested the involvement of immunologic mechanisms in the thrombocytopenia. With an increase of the platelet count after a partial splenic arterial embolization, the spleen/liver uptake ratio of the 111In-labeled platelets decreased, whereas the platelet recovery increased. Furthermore, the platelet survival time was prolonged, whereas the PA-IgG decreased. The platelet count showed a positive correlation with the platelet survival time and a negative correlation with PA-IgG before and after the procedure. These results suggest that a transcatheter splenic arterial embolization not only may reduce the increased platelet pool in the spleen but also may improve the thrombocytopenia induced by immunologic mechanisms in patients with cirrhosis.

Adult↗
PubMed1995

[A possible mechanism of interstitial pneumonia during interferon therapy with sho-saiko-to].

Interstitial pneumonia has been reported to be a side effect of treatment with interferon, and Sho-saiko-to (Xiao-Chai-Hu-Tang) may enhance this side effect. It is well known that activated neutrophils are important mediators of pulmonary fibrosis, so we studied the effects of interferon and Sho-saiko-to on neutrophil activation. Homogenized lung myeloperoxidase (MPO) activity was assayed after intraperitoneal injection of interferon with or without pretreatment with Sho-saiko-to. Although Sho-saiko-to alone did not change the lung MPO content, MPO in the lung was significantly increased by interferon administration. The increase was enhanced further by pretreatment with Sho-saiko-to. When the accumulated neutrophils are activated by some cytokines, such as TNF alpha or IL-1 beta from monocytes/macrophages, they may damage lung tissue. We therefore studied the effects of Sho-saiko-to and interferon on TNF alpha production in freshly isolated human monocytes. Sho-saiko-to increased the production of TNF alpha, but interferon did not. In addition, Sho-saiko-to significantly increased the production of TNF alpha by monocytes stimulated by lipopolysaccharide. Taken together, these data indicate that interferon causes neutrophils to accumulate in the lung. Sho-saiko-to alone may not injure lung tissue, but it increases the effect of interferon. When stimulated by some antigen, Sho-saiko-to may overstimulate the neutrophils. Granulocytes elastase and oxygen radicals released from activated neutrophils may damage lung tissue. The fibroblasts that repair the damaged tissue may increase the risk of pulmonary fibrosis.

Animals↗
PubMed1995

[Social activities in the elderly].

In order to clarify the status of social activities in the elderly, and to investigate an association between social activities and age, ADL, and geographical area, a self-administered questionnaire survey was conducted on the aged population in four areas in Japan. Social activities was defined as "activities which required contact with society" and was measured by 4 major facets of social activity, which were based on 21 questions on job activity, socially-related activities, learning activities, and personal activities. A total index was also developed by summarizing the 4 major facets as an indicator of whether the elderly is socially active or not as a whole. The following major findings emerged from this survey: (1) Rank correlation coefficients between each item which comprised 4 major activities were relatively high; (2) Excluding two activities, "shopping" and "attending senior school", aged men were more actively involved than women; (3) Trend in degrees of social activities differed by age among the 4 major facets, i.e., (a) job activity decreased with age, (b) socially-related activities and learning activities increased up to about 75 years old, and decreased thereafter, (c) personal activities were unaltered up to about 80 years old, and then decreased, and; (4) The elderly with low ADL had the lowest representation among the "highly active" in 4 major facets and total index as well.

Activities of Daily Living↗
PubMed1995

[Verification of rotational conformation radiotherapy using megavoltage CT scanning].

Although portal imaging is a promising method of verification during static multi-port irradiation, it cannot be applied directly to dynamic irradiation such as rotational conformation with multi-leaf collimator movement. A real-time beam monitoring system based on megavoltage computed tomography scanning has been developed to establish a verification method for the rotational conformation technique. The exit beam through the patient is extracted by the same detector unit as that used for megavoltage scanning during the actual treatment. The beam edge is defined as the 50% level of the maximum dose of the detector array. Megavoltage computed tomography is done after patient setup and just prior to the actual irradiation. Detected beam pathways are overlaid on this image approximately every 1 sec. Therapists can monitor the correlation between the target and actual beam pathways on a real-time computer display. The accuracy of field edge detection has been proven to be less than 2 mm from various measurements. Field errors were identified in two of 54 sessions using this method. Although several limitations remain to be solved, the method presented is an useful tool for treatment verification of high accuracy radiation therapy, particularly rotational conformation irradiation.

Brachytherapy↗
PubMed1995

Synthesis of oligonucleotides containing a carbocyclic nucleoside.

2'-Bromo-substituted cyclopentane-type carbocyclic nucleoside (7a, 7b) was synthesized from sodium cyclopentadienylide. Subsequently, 7a was incorporated into DNA oligomer by means of a conventional phosphoramidite method. Melting-temperature, CD spectra and chemical reaction of such carbocyclic oligonucleotide are described.

Base Sequence↗
PubMed1994

Radiation therapy in early glottic carcinoma: uni- and multivariate analysis of prognostic factors affecting local control.

PURPOSE: The purpose of this report is to clarify prognostic factors affecting local control of T1 and T2 glottic tumors and to define an optimal regimen for radiation therapy. METHODS AND MATERIALS: Two hundred and ten patients (199 males, 11 females, age range 30 to 86 years with an average of 62 years) with previously untreated invasive squamous cell carcinoma of the glottis were treated with radiation therapy at the University of Tokyo between January 1972 and December 1989. Endoscopic microsurgery was introduced as an integral part of treatment in 1974. From 1974 to 1979 the radiation dose was gradually reduced, reaching a mean of 20 Gy in 2 weeks in 1979. From 1980 to 1983, the total dose increased to 50.4 Gy, with a fraction size of 1.8 Gy, over a mean of 5.6 weeks. From 1984 onward, the mean total radiation dose increased to 60 Gy with a fraction of 2 Gy. RESULTS: Recurrence-free 5 year survival rates for T1a, T1b, and T2 were 79%, 73%, and 67%, respectively. When the relationship between radiation dose and local control rates was analyzed for each year from 1974 to 1989, total doses were strongly associated with local control for patients with T1a disease. Age, sex, daily dose, total dose, radiation machine (Co-60 or 10 MV Lineac), treatment technique (anterior wedged pair or parallel opposed fields), treatment volume, use of endoscopic microsurgery, and involvement of the anterior commissure were examined for effects upon relapse-free survival in T1a disease by uni- and multivariate analysis. Total dose was the only significant factor for T1a disease (p < 0.02). The effect of these variables upon relapse-free survival in T2 disease as well as the effect of cord mobility, and number of involved sites was examined by multivariate analysis. Total dose (p < 0.03), cord mobility (p < 0.05), and number of involved sites (p < 0.04) significantly affected relapse-free survival in T2 disease. CONCLUSION: At least 50 Gy is required for treatment of T1 disease when 2 Gy is used as a daily dose, even if endoscopic microsurgery is performed. Better local control of T2 disease in patients with impaired cord mobility or more than three involved sites leads to an improved prognosis; we recommend doses of at least 70 Gy or use of hyperfractionation in such patients with these factors. Although the daily dose did not significantly affect prognosis in multivariate analyses, 1.8 Gy is not recommended for treatment of T2 tumors instead of 2 Gy.

Adult↗
PubMed1994

Thermoradiotherapy in the treatment of locally advanced nonsmall cell lung cancer.

PURPOSE: To improve the treatment results of locally advanced non-small cell lung cancer (NSCLC), we have been conducting a clinical trial using regional hyperthermia combined with radiotherapy. METHODS AND MATERIALS: Between 1985 and 1990, 19 patients were treated. All cases except one were regarded as initially unresectable. There were 10 Stage IIIA cases and nine Stage IIIB cases. In 10 cases thermoradiotherapy was used definitively, and in the other nine cases preoperatively. Radiotherapy was administered with conventional fractionation. Total dose ranged from 42 to 80 Gy (mean 62.9 Gy) for definitive treatment cases, and 38 to 47 Gy (mean 40.6 Gy) for preoperative cases. Radiofrequency (RF) capacitive hyperthermia was administered twice weekly, immediately after radiotherapy. Total sessions of hyperthermia ranged from 5 to 16 times (mean 9.0) for definitive treatment cases and 3 to 8 times (mean 6.7) for preoperative cases. RESULTS: The results of thermoradiotherapy group (HTRT group) were compared with our historical control group (RT group); initially unresectable Stage III NSCLC irradiated definitively with 50 Gy or more (26 cases), or became resectable after radiotherapy and operated (4 cases). As for initial response, there were 5 complete responses (CRs), 13 partial responses (PRs), and 1 no change (NC) (CR rate 26%, response rate 95%) in the HTRT group, whereas there were no CR, 21 PRs, and 9 NCs in the RT group (CR rate 0%, p < 0.005, response rate 70%, p < 0.05). Overall 3-year local relapse-free survival and survival rate for the HTRT group was 73% and 37%, respectively, and 20% and 6.7%, respectively, for the RT group (p < 0.01, p < 0.01). The rate of death from uncontrolled primary disease for the HTRT group was significantly lower than for the RT group (21% vs. 53%, p < 0.03). CONCLUSION: Although the number of cases is rather small, thermoradiotherapy in the treatment of locally advanced NSCLC is promising in raising resectability, local control, and, thus, long-term survival.

Adolescent↗
PubMed1994

Real-time beam monitoring in dynamic conformation therapy.

PURPOSE: Although portal imaging is a promising method of verification during static multiport irradiation, it cannot be applied directly to dynamic irradiation such as rotational conformation with multileaf collimator movement. A real-time beam monitoring system based on megavoltage computed tomography scanning has been developed to establish a verification method for the rotational conformation technique. METHODS AND MATERIALS: Exit beam through the patient is extracted by the same detector unit as used for megavoltage scanning during the actual treatment. Beam edge is defined as the 50% level of the maximum dose of the detector array. Megavoltage computed tomography is done after patient setup and just prior to the actual irradiation. Detected beam pathways are overlaid on this image approximately every 1 s. Therapists can monitor correlation between the target and actual beam pathways on a real-time computer display. RESULTS: The accuracy of field edge detection has been proven to be less than 2 mm from various measurements. Real-time monitoring is more useful in rotational conformation than in static multiport irradiation due to dynamic movement of the collimator. Field errors were identified in two of 54 sessions using this method. CONCLUSIONS: Although several limitations remain to be solved, the method presented is a useful tool for treatment verification of high accuracy radiation therapy, particularly rotational conformation irradiation.

Brain Neoplasms↗
PubMed1994

Resistance to verapamil sensitization of multidrug-resistant cells grown as multicellular spheroids.

The ability of verapamil to overcome resistance to adriamycin in a multidrug-resistant derivative of the V79 cell line (LZ), grown as multicellular spheroids or as monolayers, was examined. Verapamil was much less effective in overcoming resistance to adriamycin in spheroids than in monolayers. Verapamil increased the adriamycin content of cells grown as monolayers, but had no significant effect on the drug content of spheroids. This occurred in spite of the same mdr-I mRNA and protein levels in monolayers and spheroids. When the surviving fraction of cells was normalized to the cellular adriamycin content, cells both in monolayers and spheroids treated with verapamil were still more sensitive to adriamycin than their counterparts not treated with verapamil. The observed resistance of spheroids to adriamycin and verapamil sensitization may be caused by a drug-resistance mechanism that is functional only in spheroids, in addition to the activity of P-glycoprotein. Multicellular tissue architecture and cell-cell contact may play significant roles in this type of multidrug-resistance mechanism.

Animals↗
PubMed1994

Autocrine factor enhancing the secretion of M(r) 95,000 gelatinase (matrix metalloproteinase 9) in serum-free medium conditioned with murine metastatic colon carcinoma cells.

We previously reported that murine tumor cells with a high spontaneous metastatic potential to the lung secrete higher amounts of M(r) 95,000 gelatinase (matrix metalloproteinase 9, MMP9) than do poorly metastatic cells. The present study, conducted to clarify the mechanisms underlying the increase in MMP9, revealed an autocrine factor that enhances the secretion of M(r) 95,000 gelatinase (MMP9). The secretion of MMP9 by highly metastatic colon carcinoma LuM1 cells, detected by zymography, was augmented 10-fold when cultured in medium supplemented with serum-free medium conditioned with LuM1 cells. Because the secretion of M(r) 60,000 gelatinase (MMP2), as well as total protein, by the same cells was not affected under these conditions, the augmentation appears specific for MMP9. The steady-state level of MMP9 mRNA was elevated in LuM1 cells cultured in the presence of the supernatant. The amount of the factor in the culture medium increased with time in culture, indicating that it was produced by the LuM1 cells. It was found to be heat stable but sensitive to trypsin digestion. Conditioned medium from poorly metastatic NM11 cells did not stimulate the secretion of gelatinases by NM11 cells, suggesting that autocrine stimulation of MMP9 secretion is a characteristic of metastatic cells. This factor could account for the augmented secretion of MMP9 by murine tumor cells with spontaneous metastatic potential to the lung.

Animals↗