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Biomedical subjects

A Uchida

Publications and source records attributed to A Uchida.

At least 19 recordsLinked to original sources
PubMed1996

Purification and characterization of phosphoenolpyruvate carboxylase from the hyperthermophilic archaeon Methanothermus sociabilis.

Phosphoenolpyruvate carboxylase (PEPC) was purified for the first time from hyperthermophilic archaeon Methanothermus sociabilis, growing autotrophically with an optimum at 88 degrees C. The optimum temperature for enzyme activity was similar to that for growth and was 85 degrees C. The native enzyme was a homotetramer of 240 kDa molecular mass and the subunit displayed an apparent molecular mass of 60 kDa. The archaeal PEPC was insensitive to various metabolites which are known as allosteric effectors for most bacterial and eucaryal counterparts. The enzyme showed extreme thermostability such that there remained 80% of the enzyme activity after incubation for 2 h at 80 degrees C. These results implied that archaeal PEPC was significantly different from bacterial and eucaryal entities.

Archaea↗
PubMed1996

A novel fucosyltetrahexosylceramide in plerocercoids of the parasite Spirometra erinacei.

This glycosphingolipid was tentatively designated as GalSEGLx, in which the carbohydrate structure is characterized by an additional galactose molecule attached to the reducing-end galactose of SEGLx [Gal beta-4 (Fuc alpha-3) Glc beta-3 Gal beta Cer], which was previously determined by us [Kawakami, Y., Nakamura, K., Kojima, H., Suzuki, M., Inagaki, F., Suzuki, A., Sonoki, S., Uchida, A., Murata, Y. & Tamai, Y. (1993) J. Biochem. 114, 677-683], through a beta 1-6 linkage. The ceramide contained sphinganine and 4D-hydroxysphinganine in an about equimolar ratio, and a non-hydroxy fatty acid with carbon atoms ranging from 16 to 28, 26:0, 28:0 and 28:1 being major components. Based on the finding that a novel carbohydrate structure. Gal beta-4 Glc beta-3 Gal, was commonly found in glycosphingolipids from the parasite, S. erinacei, we here propose the terms, spirometo series, for this core structure series, and spirometosides, for glycosphingolipids having this carbohydrate structure.

Animals↗
PubMed1996

Prognostic significance of Ki67 (MIB1) proliferation index and p53 over-expression in chondrosarcomas.

To investigate the prognostic significance of the Ki67 (MIBI)-proliferation index and p53 over-expression in chondrosarcomas, we retrospectively analyzed a cohort of 29 patients with chondrosarcomas using immunohistochemical assays with MIBI and p53 monoclonal antibodies on formalin-fixed, paraffinembedded tissue samples with microwave preparation. We also assessed 19 patients with benign cartilaginous tumors as a control group. There was a significant positive correlation between MIBI index and tumor grade in chondrosarcomas, while there was no significant difference in the MIBI index between the grade-1 chondrosarcomas and the benign cartilaginous tumors. Patients categorized in the high-MIBI-index group had a significantly lower survival rate than those in the low-index group. Moreover, in analyzing the sub-set of the patients with grade-II chondrosarcomas, it was found that they could be prognostically sub-divided according to MIBI index. The p53 index also significantly correlated with patient survival, and there was significant correlation between the MIBI index and the p53 index. However, in multivariate analysis, only the MIBI index and tumor grade proved to be independent prognostic indicators of chondrosarcomas. These results demonstrate that the MIBI index can be a useful procedure for assessing tumor grade in chondrosarcomas, especially for determining the prognosis of patients with grade-II chondrosarcoma.

Adolescent↗
PubMed1996

Induction of autologous tumor killing by heat treatment of fresh human tumor cells: involvement of gamma delta T cells and heat shock protein 70.

Autologous tumor killing (ATK) has been implicated as an important prognostic factor in cancer patients since the ability of blood lymphocytes to kill freshly isolated autologous tumor cells was strongly associated with good prognosis of the patients. The present study was designed to induce or enhance ATK sensitivity of fresh human tumor cells by heat stress. Brief exposure of fresh human tumor cells to elevated temperature increased their susceptibility to lysis by autologous blood lymphocytes in a short-term (51)Cr release assay. In addition, the heat-elevated ATK sensitivity was confirmed by clonogenic assays. An increase in ATK was observed with unstimulated lymphocytes in 42% of the cases and OK432 (streptococcal preparation)-activated lymphocytes in 80% of the cases. Stimulation of blood lymphocytes with autologous, heat-stressed tumor cells and OK432 resulted in an increase in number of gamma delta T cells, which was associated with elevated ATK activity against the stressed tumor cells. At the clonal level, three gamma delta T-cell clones (V gamma 9/V delta 2+) proliferated in response to autologous, heat stressed tumor cells and/or OK432 and exhibited elevated cytotoxicity against the tumor cells. Western blot analysis revealed an increased expression of heat shock protein (HSP) 70 in heat- treated tumor cells. Some of them expressed HSP70 on their surfaces. The elevated cytoxicity against heat-stressed tumor cells was inhibited by treatment of targets with anti-HSP70 monoclonal antibody (mAb) or of effector cells with anti-V delta2 mAb. Reactivity of gamma delta T cells to autologous, heat- stressed tumor cells was also inhibited by anti-HSP70 mAb. These results indicate that exposure to heat of tumor cells induces ATK susceptibility, especially to OK432-activated effector cells, and suggest that gamma delta T cells may be involved in ATK against stressed tumor cells through recognition of HSP70 on the target cells.

Adult↗
PubMed1996

Prognostic factors in angiosarcoma: a multivariate analysis of 55 cases.

Data for prognostic factors in angiosarcoma (AS) are limited, prompting a large-scale study of AS with multivariate analysis. To analyze prognostic factors in angiosarcoma (AS), clinical and histologic findings in 55 patients collected from hospitals in Japan were reviewed. Prognostic factors were evaluated by univariate and multivariate Cox's proportional hazards models. The study involved 32 males and 23 females, ages 18-93 (median, 69) years. The primary sites of tumors included head and neck (32 cases), trunk (10), extremities (3), spleen (3), breast (3), and other (4). The overall 2-year survival rate was 21%. Univariate analysis of clinical factors including age, sex, size and depth of tumor, tumor-related symptoms, interval between onset of symptoms and admission, surgical procedures, adjuvant chemotherapy, and adjuvant radiotherapy showed that age, tumor size, and mode of treatment were significant for survival. Histologic factors analyzed were mitotic counts, cellularity, cellular pleomorphism, extent of necrosis, vascular differentiation, and nonspecific diagnosis. Only mitotic counts were significant for prognosis. Multivariate analysis on these four factors revealed that tumor size, mode of treatment, and mitotic counts were independent prognostic factors.

Adolescent↗
PubMed1996

Two types of apoptotic cell death of rat central nervous system-derived neuroblastoma B50 and B104 cells: apoptosis induced during proliferation and after differentiation.

We describe here two types of apoptotic cell death observed in the rat CNS-derived neuroblastoma B50 and B104 cells. One type was induced by dibutyryl cyclic AMP (DBcAMP) after differentiation, and the other was induced by treatment of proliferating cells with cycloheximide. When B50 and B104 cells were treated with 1 mM DBcAMP in the presence of 0.5% fetal calf serum, they began to extend neurites within 12 h and differentiated into neurons at 24 h, as reported previously. However, further cultivation with DBcAMP for up to 72 h led to flotation and, finally, death. Death was by apoptosis as shown by chromatin condensation and DNA fragmentation. Addition of a protein kinase A inhibitor or removal of DBcAMP after differentiation suppressed apoptosis, indicating the involvement of cyclic AMP and protein kinase A in apoptotic cell death. Cell death was also induced in proliferating cells without neurite outgrowth by treatment with cycloheximide. The death was also judged to be by apoptosis based on chromatin condensation and apoptotic body formation, although DNA fragmentation into small sizes was not detected. Both types of cell death showed similar responses to inhibitors for protein kinases and protein phosphatases.

Animals↗
PubMed1996

Prosthetic reconstruction for periacetabular malignant tumors.

This article reports the reconstruction method and functional results of a newly designed tumor hip prosthesis with a constrained joint mechanism which was used after treatment for 13 primary and 5 metastatic periacetabular malignant bone tumors. The overall 5-year survival rate for patients with primary tumors (n=13) was 50%. The local recurrence rate was 30%. More than 90% of the patients whose hips were reconstructed with the constrained tumor hip prosthesis experienced pain relief and were able to walk with a cane. No patients had greater than 3 cm shortening of the involved limb. Infection was the most serious complication. This prosthesis restored iliofemoral stability after surgical resection of periacetabular malignant tumors.

Acetabulum↗
PubMed1996

Aeropyrum pernix gen. nov., sp. nov., a novel aerobic hyperthermophilic archaeon growing at temperatures up to 100 degrees C.

A novel aerobic hyperthermophilic archaeon was isolated from a coastal solfataric vent at Kodakara-Jima Island, Japan. The new isolate, strain K1, is the first strictly aerobic organism growing at temperatures up to 100 degrees C. It grows optimally at 90 to 95 degrees C, pH 7.0, and a salinity of 3.5%. The cells are spherical shaped and 0.8 to 1.2 microns in diameter. Various proteinaceous complex compounds served as substrates during aerobic growth. Thiosulfate stimulates growth without producing H2S. The core lipids consist solely of C25-isopranyl archaeol (glycerol diether). The G + C content of the genomic DNA is 67 mol%. Phylogenetic analysis based on 16S rRNA sequence indicates that strain K1 is a new member of Crenarchaeota. On the basis of our results, the name Aeropyrum pernix gen. nov., sp. nov. is proposed (type strain: K1; JCM 9820).

Archaea↗
PubMed1996

Rhodothermus obamensis sp. nov., a modern lineage of extremely thermophilic marine bacteria.

A novel extremely thermophilic bacterium was isolated from a shallow marine hydrothermal vent environment (depth, 22 m) in Tachibana Bay, Nagasaki Prefecture, Japan. The cells of this organism were gram-negative rods. Growth occurred at temperatures between 50 and 85 degrees C (optimum temperature, 80 degrees C; doubling time at optimum temperature, 90 min), at pH 5.5 and 9.0 (optimum pH, 7.0), and in the presence of 1 and 5% NaCl (optimum NaCl concentration, 3%). The new isolate was an aerobic heterotroph which utilized the following compounds as sole energy and carbon sources: yeast extract, peptone, starch, casein, Casamino Acids, a variety of sugars, some carboxylic acids, and amino acids. As determined by a sequence analysis of the 16S rRNA, the new isolate belongs to the genus Rhodothermus and represents a modern lineage of extreme thermophiles within the domain Bacteria. On the basis of the physiological and molecular properties of the new isolate, we describe a new species, Rhodothermus obamensis. The type strain of R. obamensis is strain OKD7 (= JCM 9785).

Base Sequence↗
PubMed1996

HHR23B, a human Rad23 homolog, stimulates XPC protein in nucleotide excision repair in vitro.

A protein complex which specifically complements defects of XP-C cell extracts in vitro was previously purified to near homogeneity from HeLa cells. The complex consists of two tightly associated proteins: the XPC gene product and HHR23B, one of two human homologs of the Saccharomyces cerevisiae repair gene product Rad23 (Masutani et al., EMBO J. 13:1831-1843, 1994). To elucidate the roles of these proteins in "genome-overall" repair, we expressed the XPC protein in a baculovirus system and purified it to near homogeneity. The recombinant human XPC (rhXPC) protein exhibited a high level of affinity for single-stranded DNA and corrected the repair defect in XP-C whole-cell extracts without extra addition of recombinant HHR23B (rHHR23B) protein. However, Western blot (immunoblot) experiments revealed that XP-C cell extracts contained excess endogenous HHR23B protein, which might be able to form a complex upon addition of the rhXPC protein. To investigate the role of HHR23B, we fractionated the XP-C cell extracts and constructed a reconstituted system in which neither endogenous XPC nor HHR23B proteins were present. In this assay system, rhXPC alone weakly corrected the repair defect, while significant enhancement of the correcting activity was observed upon coaddition of rHHR23B protein. Stimulation of XPC by HHR23B was found with simian virus 40 minichromosomes as well as with naked plasmid DNA and with UV- as well as N-acetoxy-2- acetylfluorene-induced DNA lesions, indicating a general role of HHR23B in XPC functioning in the genome-overall nucleotide excision repair subpathway.

Animals↗
PubMed1996

BCL-2 inhibits B7-induced MHC-unrestricted cytolysis mediated by a human NK cell line.

Recent work demonstrated that B7 expression by tumor cells can enhance antitumor immune responses. However, the B7 molecule is expressed abundantly on most non-Hodgkin's B-cell lymphomas and solid lymphoid tumors. How these tumor cells escape from immune surveillance mechanisms remains unclear. Lately, it has become clear that bcl-2 oncogene is overexpressed in a wide variety of human cancers and renders tumor cells more resistant to cytolytic T-cells (CTL) mediated cytotoxicity. We cloned B7 and B7/Bcl-2 transfectants and compared their susceptibilities to a human natural killer (NK) cell line and normal NK cells. The results demonstrate that Bcl-2 oncoprotein in tumor cells blocks B7-induced cytolysis mediated by a NK cell line and NK cells. Thus, they suggest that Bcl-2 oncoprotein plays a role in tumor avoidance of effective antitumor cytotoxicity.

B7-1 Antigen↗
PubMed1996

[A case of mucinous adenocarcinoma of the prostate].

We experienced a case of mucin producing prostate carcinoma, which occurred 46-year-old male patient. Serum tumor markers of prostate carcinoma were all in normal levels, and physical findings were similar to those of benign prostate hypertrophy. Histopathological study showed poorly differentiated mucinous adenocarcinoma occupying more than 30% of specimen. In literatures there seemed two types of mucin producing prostate carcinoma, the one is different from usual prostate carcinoma as our case and the other is a subtype of usual one, and so it was suggested that we must respect to this point on diagnosis and therapy of it.

Adenocarcinoma, Mucinous↗
PubMed1996

[Contingent negative variations associated with vocalization in humans].

We investigated the late negative components of the contingent negative variations (CNVs) in the verbalization task. Six subjects were instructed to perform three different motor tasks, jaw opening, vocalization of a meaningless sound and that of a word, in response to a sound stimulus following a visual warning stimulus with interstimulus interval of 4.0 sec. The electroencephalograms (EEGs) were recorded from the midline-central (Cz), left and right temporal areas (T3 and T4) and frontal areas (F7 and F8). EEGs were averaged 16 times using the visual stimulus pulse as a trigger to obtain the CNVs in each motor task. There was no significant difference between the tasks of the jaw opening and vocalization of the sound in the CNV amplitudes at bilateral electrodes. However, the amplitudes of the CNVs at the left frontal and temporal areas were significantly larger in the case of vocalization of the word than in that of jaw opening (p < 0.05). On the other hand, there was no significant difference between these two tasks in the CNV amplitudes at the right frontal and temporal areas. Our results suggested that the CNVs generated over the left hemisphere might reflect the brain activities involved in language production.

Adult↗
PubMed1996

[Perioperative fractionated high dose rate brachytherapy in bone and soft-tissue tumors].

The 13 lesions of 11 patients with bone and soft-tissue tumors (four primary and nine recurrent lesions) were treated with surgery and postoperative fractionated high dose rate (HDR) brachytherapy started on the 6-7th day after surgery. The total dose was 40-50 Gy/7-10 fr/6-7d(bid) at 5 mm from the source. Local control was achieved in eight of 13 lesions (62%). Four of the five uncontrolled lesions had macroscopic residual tumor after the surgery. There was one peripheral nerve damage as a side effect. This study indicates that the use of perioperative fractionated HDR brachytherapy is feasible and well tolerated.

Adolescent↗
PubMed1996

Blood pressure at health screening as a predictor of coronary heart disease in Kyoto.

AIM: Most epidemiologic studies that have evaluated coronary risk factors have measured either mortality or morbidity of coronary artery disease (CAD) as endpoints. However, earlier detection and elimination of coronary risk factors are crucial. We therefore performed Master's double (i.e. 1.5 min x 2 = 3 min) two-step exercise electrocardiograph (ECG) test in apparently healthy asymptomatic subjects (men, n = 2274; women, n = 959) to elucidate the risk factors for early-stage CAD or silent myocardial ischemia. METHODS: We examined the possible association of blood pressure at health screening and other suspected risk factors with exercise ECG test performance. The ischemic ECG response was determined by (1) > or = 0.5 mm horizontal or sagging S-T segment depression, (2) > or = 2.0 mm J-shaped S-T segment depression, or (3) T inversion in post-exercise ECG. RESULTS: We found that 4.7% of men and 10.6% of women exhibited ischemic responses. Among males, the ischemic responders to the exercise ECG test had higher systolic and diastolic blood pressure. In addition, the male ischemic responders were older, had a higher obesity index, higher serum cholesterol, triglyceride, low-density lipoprotein (LDL)-cholesterol, protein, glucose, and uric acid levels, and a lower serum potassium level than normal responders. In contrast, the female ischemic responders to the exercise ECG test had higher systolic pressure, and higher serum cholesterol, LDL-cholesterol, and protein levels than normal responders. Mean blood pressure was correlated positively with most of the other coronary risk factors, and mild hypertensives and hypertensives had abnormal lipid, glucose, and uric acid levels in both sexes. A comparison of risk factors by age group revealed that only younger and middle-aged ischemic responders had higher blood pressure, serum cholesterol, and glucose levels than normal responders of both sexes, and that in older subjects all the differences between normal and ischemic responders became insignificant. CONCLUSIONS: Elevated blood pressure at health screening, together with abnormal lipid and glucose metabolism, might be risk factors predicting early-stage or silent CAD. The elimination of these risk factors in younger men and women seems to be important.

Adult↗
PubMed1995

Moloney murine leukemia virus infection accelerates lymphomagenesis in E mu-bcl-2 transgenic mice.

E mu-bcl-2 transgenic mice bearing the bcl-2 proto-oncogene linked to the immunoglobulin enhancer (E mu) sporadically develop B or T cell lymphomas after a long latent period. To identify genes that play important roles in development of lymphoid malignancies, proviral insertional mutagenesis with Moloney murine leukemia virus (MMuLV) was carried out in two lines of transgenic mice expressing the bcl-2 gene primarily in B or T cells. MMuLV infection of non-transgenic mice induced primarily mature T cell lymphomas. By contrast, infection of newborn E mu-blc-2 mice with the virus accelerated lymphomagenesis, and nearly all of the mice eventually succumbed to clonal pre-B, B, or mainly immature T cell lymphoma, indicating the active contribution of the bcl-2 gene in lymphomagenesis. Southern blot analysis of tumor DNA from MMuLV-infected transgenic mice revealed a proviral insertion at the c-myc gene in 26% (9/35) of tumors, at the pim-1 gene in 6% (2/35) and at the pim-2 (recently renamed tic-1) gene in 23% (8/35). Some tumors carried two activated oncogenes. No insertion was detected at the bmi-1 gene. These data suggest the usefulness of this transgenic system for analysis of lymphomagenesis involving the activated bcl-2 gene.

Aging↗
PubMed1995

Young borderline hypertensives are hyperreactive to mental arithmetic stress: spectral analysis of R-R intervals.

To investigate whether sympathetic tone and its reactivity to stress are increased in borderline hypertension, we compared pressor and autonomic nervous responses to mental arithmetic stress in male borderline hypertensives (BH) and normotensive volunteers (NT). Three age groups, 30, 40 and 50-year-old groups, which included 30 to 39, 40 to 49 and 50 to 59-year-old subjects, were studied. Fractional LF (%LF), fractional HF (%HF) and L/H, obtained from the power spectrum of R-R intervals, were used as indices of autonomic nervous function. Baseline autonomic nervous indices did not differ between NT and BH of any age group. Blood pressure rose higher during mental arithmetic stress in 50 than in 30-year-old NT but not in comparable age groups of BH. Pressor responses were augmented in BH compared to NT only in the 30-year-old group. However, the differences were not significant when pressor responses were expressed as percent increases in blood pressure. Both %L and L/H increased during arithmetic stress. The increase in %L did not differ between NT and BH but that in L/H (% delta L/H) was larger in 50 than in 30-year-old NT. % delta L/H was larger in BH than in NT only in the 30-year-old group. These findings suggest that both pressor and autonomic nervous responses to metal arithmetic stress were altered by aging and augmented in BH compared to NT in the 30-year-old group.

Adult↗