Biomedical subjects

Y Nagata

Publications and source records attributed to Y Nagata.

At least 19 recordsLinked to original sources

PubMed1999

Activation of hematopoietic progenitor kinase-1 by erythropoietin.

Hematopoietic progenitor kinase-1 (HPK1), which is expressed predominantly in hematopoietic cells, was identified as a mammalian Ste20 homologue that, upon transfection, leads to activation of JNK/SAPK in nonhematopoietic cells. The JNK/SAPK pathway is activated by various environmental stresses and proinflammatory and hematopoietic cytokines. Upstream activators of HPK1 currently remain elusive, and its precise role in hematopoiesis has yet to be defined. We therefore examined the possible involvement of HPK1 in erythropoietin (Epo) and environmental stress-induced JNK/SAPK activation in the Epo-dependent FD-EPO cells and Epo-responsive SKT6 cells. We found that Epo, but not environmental stresses, induced rapid and transient activation of HPK1, whereas both induced activation of JNK/SAPK. A screen for HPK1 binding proteins identified the hematopoietic cell-specific protein 1 (HS1) as a potential HPK1 interaction partner. We found HPK1 constitutively associated with HS1 and that HS1 was tyrosine-phosphorylated in response to cellular stresses as well as Epo stimulation. Furthermore, antisense oligonucleotides to HPK1 suppressed Epo-dependent cell growth and Epo-induced erythroid differentiation. We therefore conclude that Epo induces activation of both HPK1 and HS1, whereas cellular stresses activate only HS1, and that the HPK1-JNK/SAPK pathway is involved in Epo-induced growth and differentiation signals.

Amino Acid Sequence↗

PubMed1999

Identification of the catalytic triad in the haloalkane dehalogenase from Sphingomonas paucimobilis UT26.

The haloalkane dehalogenase from Sphingomonas paucimobilis UT26 (LinB) is the enzyme involved in the gamma-hexachlorocyclohexane degradation. This enzyme hydrolyses a broad range of halogenated aliphatic compounds via an alkyl-enzyme intermediate. LinB is believed to belong to the family of alpha/beta-hydrolases which employ a catalytic triad, i.e. nucleophile-histidine-acid, during the catalytic reaction. The position of the catalytic triad within the sequence of LinB was probed by a site-directed mutagenesis. The catalytic triad residues of the haloalkane dehalogenase LinB are proposed to be D108, H272 and E132. The topological location of the catalytic acid (E132) is after the beta-strand six which corresponds to the location of catalytic acid in the pancreatic lipase, but not in the haloalkane dehalogenase of Xanthobacter autotrophicus GJ10 which contains the catalytic acid after the beta-strand seven.

Binding Sites↗

PubMed1999

D-Aspartate stimulation of testosterone synthesis in rat Leydig cells.

D-Aspartate increases human chorionic gonadotropin-induced testosterone production in purified rat Leydig cells. L-Aspartate, D-,L-glutamate or D-,L-asparagine could not substitute for D-aspartate and this effect was independent of glutamate receptor activation. Testosterone production was enhanced only in cells cultured with D-aspartate for more than 3 h. The increased production of testosterone was well correlated with the amounts of D-aspartate incorporated into the Leydig cells, and L-cysteine sulfinic acid, an inhibitor of D-aspartate uptake, suppressed both testosterone production and intracellular D-aspartate levels. D-Aspartate therefore is presumably taken up into cells to increase steroidogenesis. Intracellular D-aspartate probably acts on cholesterol translocation into the inner mitochondrial membrane, the rate-limiting process in steroidogenesis.

Animals↗

PubMed1999

A longitudinal study of the effect of vitamin K2 on bone mineral density in postmenopausal women a comparative study with vitamin D3 and estrogen-progestin therapy.

OBJECTIVES: To investigate the effect of vitamin K2 treatment for a year on spinal bone mineral density (BMD) in postmenopausal women, comparing with vitamin D3 hormone replacement therapy and to determine the factors which affect the efficacy of vitamin K2 therapy. SUBJECTS AND METHODS: Seventy-two postmenopausal women were randomized into four groups and treated with respective agents. Before the therapy, 6 and 12 months after the treatment, their lumbar spine BMD were measured by dual energy X-ray absorptiometry. The rates of change in BMD (delta BMD) were calculated. Correlations of BMD with age, year since menopause and the initial BMD were determined. RESULTS: Vitamin K2 suppressed the decrease in spinal BMD as compared with no treatment group. BMD in women treated with vitamin K2 was inversely correlated with their age (r = -0.54; P < 0.05). CONCLUSIONS: Vitamin K2 therapy may be a useful method for preventing postmenopausal spinal bone mineral loss. In addition, the therapy should be started early in postmenopausal period.

Bone Density↗

PubMed1999

Bone mineral density in postmenopausal women with endometrial cancer.

OBJECTIVE: The aim of the study was to investigate the relationship between endometrial cancer and bone mineral density (BMD). MATERIALS AND METHODS: A total of 55 postmenopausal Japanese women with well-differentiated adenocarcinoma and 284 age-matched healthy women were studied. Baseline characteristics including age, age at menopause, years since menopause (YSM), weight, height, body mass index (BMI), prior menstrual history, parity, and fertility were recorded for each subject. Lumbar spine BMD (L2-4), and body fat indices including body fat mass amount and percent body fat were measured by dual-energy X-ray absorptiometry. These variables were compared between the two groups. In all subjects (n = 339), correlations of BMD with the presence of endometrial cancer, baseline characteristics, and body fat indices were investigated, using univariate and multiple regression analyses. RESULTS: BMD, weight, BMI, body fat mass amount, and percent body fat were significantly higher in women with endometrial cancer. Other baseline characteristics did not differ between the two groups. Age at menopause, height, weight, BMI, percent body fat, and body fat mass amount were positively correlated with BMD, while age and YSM were inversely correlated with BMD. After adjusting for age, YSM, and height, the presence of endometrial cancer was still correlated with BMD (P < 0.05). However, after adding body fat mass amount to these three adjusted variables, there was no correlation between the presence of endometrial cancer and BMD. CONCLUSION: Women with endometrial cancer have a high BMD. This is attributable to high body fat mass amount in this disease.

Adenocarcinoma↗

PubMed1999

Measurement of obstetric conjugate by ultrasonic tomography and its significance.

OBJECTIVE: The purpose of this study was to investigate the clinical usefulness of the measurement of ultrasonic obstetric conjugate. STUDY DESIGN: In 209 pregnant women, ultrasonic obstetric conjugate was measured twice at 28 and 36 weeks of pregnancy. In 26 of these patients the measurement of obstetric conjugate by x-ray pelvimetry was also performed at 36 weeks of pregnancy because of medical indications. Obstetric outcome was investigated in association with ultrasonic obstetric conjugate. The relationship between ultrasonic obstetric conjugate and x-ray pelvimetry was investigated. RESULTS: Ultrasonic obstetric conjugate ranged from 10.7 to 15.1 cm. In 12 patients (5.7%) ultrasonic obstetric conjugate was less than 12 cm. Six of them (50.0%) underwent cesarean section because of dystocia. This percentage was significantly higher than 7.1% of the cesarean section rate (14 of 197) in patients with ultrasonic obstetric conjugate more than 12 cm (P <.001). A close positive correlation was observed between ultrasonic obstetric conjugate and x-ray pelvimetry (r = 0.91; P <.0001). CONCLUSIONS: We conclude that ultrasonic obstetric conjugate measurement is a safe and useful procedure in the prediction of dystocia.

Adult↗

PubMed1999

Differences in target outline delineation from CT scans of brain tumours using different methods and different observers.

PURPOSE: To assess errors resulting from manual transfer of contour information for three-dimensional (3-D) target reconstruction, and to determine variations in target volume delineation of brain tumours by different radiation oncologists. MATERIALS AND METHODS: Images of 18 patients with intracranial astrocytomas were used for retrospective treatment planning by five radiation oncologists. In this study, the target outline was delineated on sequential CT slices by an experienced radiation oncologist. Thereafter, the target outline was manually reconstructed by five radiation oncologists onto an A-P or lateral scout film. The same target outline was also reconstructed as a projection using the Beam's-eye view capability on a CT simulator unit. The two target outlines were compared by encompassing each shape with the smallest rectangle. The manually-reconstructed radiation field was termed 'Field manually established on X-ray film (F-X)', and the automatically-established field was termed 'Field established by CT simulator (F-CT)'. In a second part of this study, four radiation oncologists defined contours from contrast enhanced CT images of nine patients with intracranial astrocytomas. The CT images of these nine cases included five pre-operative cases and four post-operative cases. Both gross tumour volume (GTV) and clinical target volume (CTV) were outlined on sequential CT slices. The target outlines for the four radiation oncologists were compared by identifying the smallest rectangular field surrounding the projection of these contours. The field established by each radiation oncologist was termed 'Field of target volume (F-TV)', and the overlapping portion of the four F-TVs for each case was termed 'Overlapped field of the target volume (Fo-TV)'. RESULTS: The average distance between the isocentres of F-X and F-CT was 0.6 +/- 0.4 cm (mean +/- SD). The average ratio of the area of F-X divided by the area of F-CT was 1.04 +/- 0.12. The area of F-X was wider than the area of F-CT for four of the five oncologists. The ratio of the area of F-TV divided by the area of Fo-TV was calculated. The average ratio was relatively greater for CTV (2.07 in pre-operative cases and 2.11 in post-operative cases) than for GTV (1.12 in pre-operative cases and 1.41 in post-operative cases). Among radiation oncologists, variations in the delineation of GTV were smaller than those of CTV. CONCLUSIONS: When using an X-ray simulator in treatment planning, errors resulting from the manual transfer of CT contour information to planar radiographs must be considered. When computer techniques are used to project contours onto radiographs errors resulting from individual variations when performing the contouring must be considered.

Astrocytoma↗

PubMed1999

A novel panoramic machine for photofluorography.

OBJECTIVE: To describe the main features of a prototype panoramic X-ray machine modified for photofluorography. METHODS: The prototype PTM 2001 (Asahi Roentgen, Kyoto, Japan) consists of a conventional panoramic machine with a modified X-ray generator and incorporating a 9-inch image intensifier and a photofluorographic camera. RESULTS: The photofluorographic panoramic radiograph is reduced in size by 60% compared with conventional images. Using 10 cm x 45.7 m photoradiographic film 250 panoramic images can be continuously obtained. Examination time is shorter since cassette changes are not necessary. The radiation dose-in-air, measured in front of the secondary collimator, is 174 muGy. CONCLUSIONS: The advantages of the photofluorographic panoramic radiography include cost economy, shorter examination time and lower radiation exposure.

Equipment Design↗

PubMed1999

Clinical results of transcatheter arterial infusion for uterine cervical cancer.

The effects of transcatheter intraarterial infusion of anticancer drugs on the prognosis of cervical cancer were retrospectively studied. Two or three sessions of transcatheter arterial infusion therapy were performed for 68 patients with primary uterine cervical cancer. The number of patients with stage I, II, III, or IV disease were 13, 22, 24, and 9, respectively. Patients with squamous cell carcinoma comprised 3, 17, 17, and 5 of the respective groups, and the patients with stage I and II disease had either adenocarcinoma or adenosquamous carcinoma, or bulky tumor (>4 cm). The drugs infused were cisplatin (60-70 mg/m2), doxorubicin hydrochloride (30-40 mg/m2), mitomycin (15 mg/m2), and 5-fluorouracil (500 mg/body). They were infused via the bilateral internal iliac arteries. Fifty-eight of the 68 patients (85%) received a radical hysterectomy after transcatheter arterial infusion: 12 of 13 with stage I disease, 21 of 22 with stage II disease, 20 of 24 with stage III disease, and five of nine with stage IV disease. Two patients with stage III disease received radical radiotherapy. The other eight patients (one with stage I disease, one with stage II disease, two with stage III disease, and four with stage IV disease) did not receive an operation after transcatheter arterial infusion because they had distant metastases at the time of operation. Thirty-two of 58 patients (56%) received postoperative radiotherapy. The complete histologic response rates (no active cancer cells) after transcatheter arterial infusion were: 2 of 12 patients with stage I disease, 3 of 21 patients with stage II disease, 5 of 20 patients with stage III disease, and one of five patients with stage IV disease. Tumors with squamous cell carcinoma disappeared at a significantly better rate (10/36, 28%) than did tumors with adenocarcinoma or adenosquamous cell carcinoma (1/22, 5%; p < 0.05). The overall 5-year survival rates of the patients with stages I, II, and III disease were 92.3%, 62.2%, and 71%, respectively. The 5-year survival rates of the patients who underwent surgery with stage I, II, and III disease were 100%, 66.3%, and 71.5%, respectively. Leukocytopenia and thrombocytopenia occurred as an acute complication in 75% and 79% of the patients, respectively. As a late complication, ileus occurred in 7%. Transcatheter arterial infusion may improve the prognosis of patients with cervical cancer without increasing the incidence of late complications.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1999

Crystallization and preliminary X-ray diffraction analysis of haloalkane dehalogenase LinB from Sphingomonas paucimobilis UT26.

Haloalkane hydrolytic dehalogenase LinB from Sphingomonas paucimobilis UT26, an enzyme which releases chloride or bromide anion from n-halogenated alkanes and has a broad range of substrate specificity, was crystallized using the hanging-drop vapour-diffusion method at 278 K. The best crystals were obtained by microseeding with a precipitant containing 18-20%(w/v) PEG 6000, 0.2 M calcium acetate and 0.1 M Tris-HCl pH 8.9. The crystals diffract to at least 1.60 A using synchrotron X-ray under cryogenic (100 K) conditions. They belong to the orthorhombic space group P21212 with unit-cell parameters a = 50.29, b = 71.70, c = 72.73 A. The asymmetric unit contains one molecule of the enzyme.

Crystallization↗

PubMed1999

Technetium-99m complexes with steroid-2-aminooxyethyliminodiacetic acid conjugates.

Conjugates of 2-aminooxyethyliminodiacetic acid with estrone, testosterone, epiandrosterone, 17-alpha-hydroxy-progesterone and progesterone were synthesized and their complexes with Tc-99m were successfully prepared in good yields, which indicated the agent to be promising for metal-labeling of biomolecules and related substances containing one or more carbonyl groups. The biodistribution and scintigraphic studies in mice bearing Ehrlich tumor and mammary tumor showed that the radioactivity accumulated considerably in the tumor tissues, but the tumor images were somewhat obscured.

Animals↗

PubMed1999

Bone marrow-derived dendritic cells incorporate and process hydrophobized polysaccharide/oncoprotein complex as antigen presenting cells.

We have previously shown that a novel hydrophobized polysaccharide/oncoprotein complex vaccine can induce immune responses against the HER2/neu/c-erbB2 (HER2) expressing tumors. Bone marrow-derived dendritic cells (DCs), as antigen presenting cells (APCs), are the first candidates for presentation of tumor antigens. The aim of this study was to see whether DCs are able to elicit antigen specific host immune responses by stimulating the proliferation of T cells after exposure to cholesteryl group bearing pullulan (CHP) and HER2 protein complex. Vaccination by CHP-HER2 complex was as effective as cholesteryl group bearing mannan (CHM) and HER2 complex on which we reported previously. Immunization of mice with HER2 expressing CMS17HE tumor cells generated both CD4+ T cells and CD8+ T cells reactive with CHP-HER2 complex pretreated DCs. In addition, immunization with either CHP-HER2 complex or HER2 protein alone could also generate both CD4+ T cells and CD8+ T cells specifically reactive with CHP-HER2 complex pretreated DCs. The complete rejection of tumors occurred when immunization with CHP-HER2 complex pretreated DCs was started 10 days after tumor inoculation. Therefore, bone marrow-derived DCs pretreated with hydrophobized polysaccharide/oncoprotein complex are a powerful tool for enhancing the effectiveness of oncoprotein for anti-tumor vaccination, opening new options for immune cell therapy.

Animals↗

PubMed1999

Brasilicardin A, a new terpenoid antibiotic from pathogenic Nocardia brasiliensis: fermentation, isolation and biological activity.

A novel tricyclic diterpenoid antibiotic, brasilicardin A, was isolated from the culture broth of Nocardia brasiliensis IFM 0406. The antibiotic exhibited immunosuppressive activity in a mouse mixed lymphocyte reaction (MLR) assay system and its IC50 value was 0.057 microg/ml. Although the inhibitory activity of cyclosporin A (CyA) against IL-2 production was confirmed in the MLR assay system, brasilicardin A did not have the activity. The results of in vitro toxicity testing of brasilicardin A against various human cell lines were compared with those of CyA.

Aminoglycosides↗

PubMed1998

Effects of SN-38 (an active metabolite of CPT-11) on responses of human and rodent cells to irradiation.

PURPOSE: Modulators of the DNA-unwinding enzyme, topoisomerase I (Topo I), inhibit DNA repair and have been reported to increase the lethal effects of X rays, which create breaks in DNA. CPT-11 is a derivative of camptothecin, a Topo I inhibitor, and is clinically available. In this study, we tested the in vitro combination effects of SN-38, an active form of CPT-11, and irradiation on several cell lines. MATERIALS AND METHODS: Exponentially growing or confluent cultures of CHO cells were treated with SN-38 for 30 min. Cells were then irradiated. Thereafter, the cells were further incubated with the drug for 0 to 3 h. Exponentially growing other cell lines were exposed to 200 nM SN-38 for 30 min before, during, and 3 h after irradiation. The cell survival rate was determined using a conventional clonogenic assay. RESULTS: SN-38 (200 nM to 4 microM) alone showed slight toxicity to CHO cells in the confluent culture after a 3.5-h incubation. When the cells were treated with the lower doses of SN-38 (50 to 800 nM) during the exponentially growing phase, the cell survival rates were much lower. In combination with irradiation, SN-38 showed only additive effects to irradiation when cells were treated in confluent cultures. However, higher combination effects of SN-38 and irradiation were observed in the cells treated in the exponentially growing phase. When cells were irradiated during the exponentially growing phase, a significant combination effect of 200 nM SN-38 and irradiation was also observed in some cell lines, but not in others. CONCLUSION: SN-38 and irradiation showed supraadditive effects in some cell lines, when treated in the exponentially growing phase, but not in other cell lines or when cells were treated in the confluent phase.

Animals↗

PubMed1998

Activation of p38 MAP kinase and JNK but not ERK is required for erythropoietin-induced erythroid differentiation.

p38 MAP kinase (p38) and JNK have been described as playing a critical role in the response to a variety of environmental stresses and proinflammatory cytokines. It was recently reported that hematopoietic cytokines activate not only classical MAP kinases (ERK), but also p38 and JNK. However, the physiological function of these kinases in hematopoiesis remains obscure. We found that all MAP kinases examined, ERK1, ERK2, p38, JNK1, and JNK2, were rapidly and transiently activated by erythropoietin (Epo) stimulation in SKT6 cells, which can be induced to differentiate into hemoglobinized cells in response to Epo. Furthermore, p38-specific inhibitor SB203580 but not MEK-specific inhibitor PD98059 significantly suppressed Epo-induced differentiation and antisense oligonucleotides of p38, JNK1, and JNK2, but neither ERK1 nor ERK2 clearly inhibited Epo-induced hemoglobinization. However, in Epo-dependent FD-EPO cells, inhibition of either ERKs, p38, or JNKs suppressed cell growth. Furthermore, forced expression of a gain-of-function MKK6 mutant, which specifically activated p38, induced hemoglobinization of SKT6 cells without Epo. These results indicate that activation of p38 and JNKs but not of ERKs is required for Epo-induced erythroid differentiation of SKT6 cells, whereas all of these kinases are involved in Epo-induced mitogenesis of FD-EPO cells.

Animals↗

PubMed1998

D-serine content and D-[3H]serine binding in the brain regions of the senescence-accelerated mouse.

An established senescence-accelerated model mouse strain, SAMP8, shows the deterioration of learning and memory compared with a normal control strain, SAMR1. D-Serine binds to strychnine-insensitive glycine binding sites of the N-methyl-D-aspartate (NMDA) receptor complex, and enhances glutamate binding to the receptor complex. To investigate the relationship of endogenous brain D-serine and the brain dysfunction caused by aging, the level of brain free D-serine and the D-[3H]serine binding to the brain samples were examined using the SAMP8 and SAMR1 mice. The free D-serine level was highest in the cerebral frontal and occipital cortices in both the SAMP8 and SAMR1; no difference in the D-serine level was shown between the two strains. A receptor autoradiographical analysis showed that the D-[3H]serine binding to the brain section was highest in the hippocampus, and the binding in the SAMP8 brains was lower than that of the SAMR1. The D-[3H]serine binding to the crude cerebral membranes indicated that the value of the total binding sites for the SAMP8 was lower than that for the SAMR1, whereas the value of the dissociation constant Kd for the SAMP8 was similar to that of the SAMR1. These results suggest that the number of D-[3H]serine binding sites was decreased in the SAMP8 compared to the SAMR1, but the affinity of D-[3H]serine to the binding sites was not altered. These results support the view that a decrease of NMDA receptor complex is involved in the age-related neural dysfunction of SAMP8 mice.

Aging↗

PubMed1998

A novel hydrophobized polysaccharide/oncoprotein complex vaccine induces in vitro and in vivo cellular and humoral immune responses against HER2-expressing murine sarcomas.

To elicit specific cellular immune responses against cancer, the development of efficient devices to deliver tumor antigen peptides to the MHC class I pathway constitutes a central issue. We report here a novel formula of hydrophobized polysaccharide nanoparticles, which can deliver a HER2 oncoprotein containing an epitope peptide to the MHC class I pathway. A protein consisting of the 147 amino-terminal amino acids of oncogene erbB-2/neu/HER2 (HER2) was complexed with two kinds of hydrophobized polysaccharides, cholesteryl group-bearing mannan (CHM) and cholesteryl group-bearing pullulan (CHP), to form nanoparticles (CHM-HER2 and CHP-HER2). CHM-HER2 and CHP-HER2 were able to induce CD3+/CD8+ CTLs against HER2-transfected syngeneic fibrosarcoma cell lines. In contrast, the oncoprotein alone failed to do so. These CTLs were Kd-restricted and specifically recognized a peptide (position 63-71) that was a part of a truncated HER2 protein used as an immunogen. In addition, vaccination by CHM-HER2 complexes led to a strongly enhanced production of IgG antibodies against HER2, whereas vaccination with HER2 proteins alone resulted in a production of antibodies at a marginal level. Mice immunized with CHM-HER2 or CHP-HER2 before tumor challenge successfully rejected HER2-transfected tumors. The complete rejection of tumors also occurred when CHM-HER2 was applied not later than 3 days after tumor implantation. In the effector phase of in vivo tumor rejection, CD8+ T cells played a major role. The results suggest that a sort of hydrophobized polysaccharide may help soluble proteins to induce cellular immunity as well enhance humoral immunity; hence, such a novel vaccine may be of potential benefit to cancer prevention and cancer therapy.

Animals↗

PubMed1998

The effect of menopause on regional and total body lean mass.

OBJECTIVES: To investigate the effect of menopause on regional and total body lean mass. METHODS: Evaluation of 123 healthy premenopausal women (40.6 +/- 10.8 years) and 123 healthy postmenopausal women (61.8 +/- 7.5 years). All subjects were right side dominant. Regional (head, bilateral arms, trunk, and bilateral legs) and total body lean mass were measured using whole-body scanning by dual-energy X-ray absorptiometry. Baseline characteristics including age, height, weight, and menopausal state were recorded. These variables were compared between pre- and postmenopausal women. In all subjects, correlations between regional or total body lean mass and baseline characteristics were investigated using univariate and multiple regression analyses. RESULTS: Height, and lean mass of the trunk, bilateral legs and total body were significantly lower in postmenopausal women than in premenopausal women, while lean mass of the bilateral arms did not differ between the two groups. On univariate regression analysis, bilateral arms lean mass was positively correlated with height (P < 0.001). Trunk, bilateral legs, and total body lean mass were inversely correlated with age and menopausal state (P < 0.001), but were positively correlated with height (P < 0.001). After adjusting for age and height, trunk lean mass was still correlated with menopausal state (P < 0.01). CONCLUSIONS: Menopause induces lean mass loss, independent of aging and height. Trunk lean mass is more prone to decline with menopause than lean mass of other sites.

Adult↗