Search PubMed⌕ Search

Biomedical subjects

Y Yamamura

Publications and source records attributed to Y Yamamura.

At least 181 records · Page 10Linked to original sources
PubMed1995

A mouse erythroleukemia cell line possessing friend spleen focus-forming virus gp55 transgene and temperature-sensitive mutant p53 gene.

Two different erythroleukemia cell lines have been established from the splenic lesions of transgenic mice possessing the Friend spleen focus-forming virus (F-SFFV) gp55 gene. One showed a near-diploid karyotype and a temperature-sensitive (ts) p53 mutation, and the other, a hyper-triploid karyotype with double p53 mutations found by single-strand conformation polymorphism (SSCP) analysis. The cell lines both retained No.11 chromosomes on which p53 genes are localized. Another p53 allele in the cell line with the ts-p53 mutation appeared intact in the SSCP analysis of the genomic exon 5. The cells with the ts-mutant p53 gene showed no apparent change with temperature shift in their growth or dimethylsulfoxide-induced differentiation, although the wild-type p53 gene on the other allele was not expressing. This ts-p53Val-135 gene made p53-deficient fibroblasts anchorage-independent at 37 degrees C but not at 32 degrees C. This non-virus-producing, mouse erythroleukemia cell line will be useful for the study of mutated p53 function during the induction of erythrodifferentiation or apoptotic change.

Animals↗
PubMed1995

Corticotropin releasing hormone in colonic mucosa in patients with ulcerative colitis.

Corticotropin releasing hormone (CRH) is a key hormone in integrated response to stress, acting as the major regulator of the hypothalamic-pituitary-adrenal axis. Recently, local production of CRH has been detected in normal human colonic enterochromaffin cells. CRH is locally secreted in granulomatous and arthritic tissues in rats and humans, where it seems to act as a local proinflammatory agent. To find out if CRH is present in colonic tissues of patients with ulcerative colitis, this study examined the expression of this peptide in the large bowel of patients with ulcerative colitis. Colonic tissues of patients with ulcerative colitis obtained by endoscopic biopsy were immunostained with anti-CRH antibody. CRH messenger (m) RNA was also examined in biopsy specimens of ulcerative colitis by the reverse transcribed polymerase chain reaction method and by in situ hybridisation. Considerably enhanced expression of immunoreactive CRH was found in mucosal inflammatory cells. Intense staining with anti-CRH antibody was also shown in mucosal macrophages. CRH mRNA was expressed in mucosal epithelial cells. The expression of immunoreactive CRH in colonic mucosal epithelial cells of ulcerative colitis slightly increased, but not significantly, compared with normal colonic mucosal epithelial cells. These results suggest that CRH may play a part in the modulation of intestinal immune and inflammatory system, and as a modulator in the pathogenesis of ulcerative colitis.

Adult↗
PubMed1995

Administration-route dependency of absorption of glycyrrhizin in rats: intraperitoneal administration dramatically enhanced bioavailability.

The pharmacokinetic behavior of glycyrrhizin after intravenous (i.v.), oral and intraperitoneal (i.p.) administration was compared in rats. The elimination half-life, total body clearance and volume of distribution at steady-state of glycyrrhizin were not significantly different among doses (2, 10 and 50 mg/kg i.v.). Glycyrrhizin was only detected in the plasma (maximum level: 1.3 micrograms/ml) after oral administration of 50 mg/kg. From comparison of the area under the plasma concentration-time curves after i.v. and oral administration of 50 mg/kg, the bioavailability of glycyrrhizin was estimated to be approximately 1%. Glycyrrhizin was stable for at least 3 h in gastric juice. The plasma concentration of glycyrrhizin after oral administration to neomycin-treated rats was not significantly different from that after administration to untreated rats. Furthermore, in in situ absorption study the cumulative ratio of glycyrrhizin in the mesenteric venous plasma after injection was only 1-2% of the dose. From these results, it appeared that the extremely low bioavailability by the oral route may be due to poor absorption of glycyrrhizin from the intestinal tract. On the other hand, the plasma concentration of glycyrrhizin rapidly increased after i.p. administration of doses of 2, 10 and 50 mg/kg, and reached a maximum level (4.7, 33.0 and 238.9 micrograms/ml, respectively) within 30 min. The bioavailability (65-90%) of glycyrrhizin after i.p. administration was enhanced dramatically. The i.p. route of administration may thus improve the bioavailability of glycyrrhizin.

Animals↗
PubMed1995

OPC-21268 antagonizes arginine vasopressin-induced vasoconstrictor response in the spinally-anesthetized dog.

We studied the antagonistic actions of OPC-21268 (1-(1-[4-(3-acetylaminopropoxy)-benzoyl]-4-piperidyl)-3,4-dihydro- 2(1H)-quinolinone) on the arginine vasopressin (AVP)-induced vasoconstrictor response in the spinally-anesthetized dog. OPC-21268 at doses of 0.3, 1.0 and 3.0 mg/kg, i.v. produced a rightward parallel shift of the dose-response curves for AVP in a dose-dependent manner. The doses of OPC-21268 were similar to those that inhibited the AVP-induced vasoconstrictor response in the rat. This observation suggests that OPC-21268 acts as a V1-AVP-receptor antagonist in peripheral resistance vessels in dogs as well as in rats.

Animals↗
PubMed1995

Estimation of bone mineral density and bone loss by means of bone metabolic markers in postmenopausal women.

We have examined healthy women (51 premenopausal women and 30 postmenopausal women; age 28-59) for lumbar bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA) and assessed metabolic bone markers, such as type I procollagen carboxy-terminal propeptide (P1CP), pyridinoline (PYR), deoxypyridinoline (DPYR), osteocalcin (BGP) and alkaline phosphatase (ALP). BMD was assessed once a year in three consecutive years. Correlations among the BMD, BMD changes and levels of bone markers in samples at the first DXA assessment were studied. In pre-menopausal women, none of the biochemical markers were correlated with the BMD or changes in BMD. In contrast, BMD in post-menopausal women correlated (negatively) well with levels of P1CP, DPYR, PYR and ALP declining in this order, and a significant positive correlation was observed between the rate of bone loss in postmenopausal women and the P1CP concentration. PYR and DPYR also had a tendency to correlate. Combinations of several bone markers improved the correlation. These results show that by measuring several bone specific biochemical markers in postmenopausal women, one can estimate their rates of bone loss as well as their present BMDs. The measurement of biochemical bone markers will therefore be very useful in evaluating bone status and would be applicable in screening postmenopausal osteopenia.

Adult↗
PubMed1995

Infrequent mutations of the WT1 gene in primary cancers of the adult urinary tract.

Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis of all of the ten exons of the WT1 gene and restriction fragment length polymorphism (RFLP) analysis of the WT1 locus were performed on primary urinary tract cancers: seven renal pelvic cancers, one ureteral cancer, 11 bladder cancers, and 22 renal cell cancers. Four human bladder cancer cell lines (T24, JTC30, JTC32, and HUB41) and three human prostate cancer cell lines (PC-3, DU145, and LNCaP) were also examined. None of the primary cancers showed any apparent mutations of the gene, whereas one base substitution of exon 5 was found in DU 145 and gross alteration of the gene was recognized in HUB41. Heterozygosity of polymorphic exon 7 was retained in all of the 12 informative cases, and none of 10 informative cases showed loss of heterozygosity at the WT1 locus in RFLP analysis. It is concluded that mutations of the WT1 gene may not be involved in the formation of malignant tumors of the adult urinary tract.

Adult↗
PubMed1995

[Relationship between impaired blood pressure control and multiple system involvement in chronic alcoholics].

Chronic ethyl alcohol (ethanol) abuse is associated with different types of neurological involvement. Impaired blood pressure control such as in hypertension and/or orthostatic hypotension is a known autonomic dysfunction in chronic alcoholics. Although abstinence appears to improve blood pressure, the precise mechanisms underlying the effects of alcohol remain unknown. We suspected that abnormal blood pressure might influence the outcome of alcohol-related neurological symptoms. We therefore reviewed the alcohol history of 28 male patients admitted to our hospital with multiple system involvement. No family history of spinocerebellar degeneration was found. All of the patients had a history of chronic alcohol abuse. The duration of alcohol abuse in 28 patients was 28.8 + 11.2 yrs. Daily ethanol consumption was less than 83 ml in 6 patients between 83 ml and 138 ml in 11 and more than 138 ml in 11. We assessed the relationship between impaired blood pressure control, clinical characteristics, and outcome after abstinence for a period ranging from 30 days to 6 years in 22 chronic alcoholics who had drunk more than 83 ml/day. All of the patients had various types of autonomic dysfunction, and a high incidence of impaired blood pressure control and decreased CVR-R were noted. The symptoms improved or even completely resolved after cessation of alcohol consumption, however, 8 of the 22 patients in our study reached a plateau and have permanent symptoms. Patients with no improvement as a result of abstinence had a long history of excessive drinking. Brain CT/MRI, SPECT and P300 studies were conducted. SPECT and P300 were performed in both the supine and standing position in 5 and 7 patients, respectively. Five patients who had severe orthostatic hypotension with syncope were found to have cerebrovascular lesions on MRI. Changes in P300 amplitude and/or distribution and latency were noted after a fall in blood pressure. Although the etiology of impaired blood pressure control in alcoholics remains unknown, we believe that abnormal blood pressure affects the outcome of alcohol-related neurological symptoms.

Adult↗
PubMed1995

[Vasomotor impairment in patients with diabetic neuropathy--evaluation by laser Doppler flowmetry].

Using laser Doppler flowmetry, we evaluated cutaneous microcirculation in 28 patients with diabetic neuropathy and 18 control subjects. Skin blood flow in the hand was significantly reduced in the patients compared with that in age-matched controls. Skin blood flow in the hand of the patients correlated significantly with the amplitude of sensory nerve action potential of the median nerve. Significant correlation was shown in the patients between skin blood flow in the hand and changes in systolic blood pressure on standing from a supine position. However, there was no correlation between skin blood flow in the hand and variation in the R-R interval. These results suggest that the skin blood flow may decrease with the progression of diabetic neuropathy, particularly sympathetic autonomic neuropathy, and that neural control may be an important factor in the regulation of skin blood flow. Cold water immersion test revealed that there was no significant difference in vasoconstrictive response during the cold challenge, while recovery time of vasodilatory response after withdrawal of the thermal challenge was significantly prolonged in the patients as compared with that in the controls. In addition, it is suggested that the patients with a small increase or normal in skin blood flow of the hand may possess abnormalities predominantly in vasoconstrictive tone, whereas the patients with a decrease in skin blood flow of the hand in vasodilatory tone. Consequently, microcirculation in skin of extremities changes under the balance of vasoconstrictive and vasodilatory tones in patients with diabetic neuropathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Diabetic Neuropathies↗
PubMed1995

Aquaretic effect of a potent, orally active, nonpeptide V2 antagonist in men.

Solute-free water diuretics (aquaretics) that antagonize hydrosmotic vasopressin 2 (V2) receptors may be useful in treating diseases in which water is retained. An orally active, nonpeptide, selective V2 antagonist (OPC-31260) was administered in six dose steps (3, 15, 30, 60, 100 and 200 mg) to six healthy, normally hydrated men to investigate the aquaretic effects in comparison with 12 placebo-treated control subjects (two at each dose). All subjects tolerated all six doses without serious clinical side effects. OPC-31260 increased the first 6-hr hypotonic urine volume dose-dependently. Administration at 30 mg raised the 6-hr urine volume to 2 times, 100 mg to 3 times and 200 mg to 4 times (1828.0 +/- 130.2 ml/6 hr) that of the placebo group (470.4 +/- 52.1 ml/6 hr). The drug increased urine flow maximally between 1 and 1.5 hr at all doses (e.g., 10.0 +/- 0.7-10.8 +/- 0.4 ml/min at 60-200 mg). The drug rapidly lowered urine osmolality for 4 hr, particularly between 60 and 90 min (e.g., 72.3 +/- 2.3 and 62.3 +/- 5.1 mOsm/kg at 100 and 200 mg, respectively). In marked hypotonic diuresis, mean free-water clearance of the 6-hr urine increased dose-proportionally into the positive range, reaching 2.82 +/- 0.21 ml/min at 200 mg.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

A new flow cytometric method for quantitative assessment of lymphocyte mitogenic potentials.

A new flow cytometric method was developed to quantitatively assess lymphocyte proliferation simultaneously for different subsets. The cells were stained with a fluorescent dye, PKH-26 and were stimulated with mitogens. The fluorescence intensities (FL2) of proliferating cells were measured by flow cytometry; and each subset was identified by the use of a monoclonal antibody (Mab)-fluorescein-isothiocyanate (FITC) (FL1). FL2 histograms were then analyzed by the cell proliferation model based on the ModFit software (Verity). This new method revealed information which could not be obtained by conventional mitogen assays. For example, the CD4+ and the CD4- T-subsets responded to phytohemagglutinin (PHA) quite differently from each other and it was indicated that activation of one population could significantly alter the response of the other. In addition, even within a subset, all activated cells did not proliferate uniformly. Some cells divided only once while others underwent further cellular division during the same time period. The method is, therefore, invaluable for studying the nature and the extent of interactions between different cellular subsets within a culture.

Antibodies, Monoclonal↗
PubMed1995

Anti-CD4 cytotoxic T lymphocyte (CTL) activity in HIV+ patients: flow cytometric analysis.

A new cell proliferation analysis by flow cytometry was applied to the mitogen induced cultures of peripheral blood mononuclear cells (PBMC) from either normal, healthy donors or those individuals who are infected by human immunodeficiency virus, type 1 (HIV-1). While phytohemagglutinin (PHA) stimulation of normal PBMC (nPBMC) yielded propagation of both CD4 (nCD4) and CD8 (nCD8) T cell subsets, similar activation of PBMC from certain HIV-1-infected individuals (HIV-PBMC) produced active proliferation of CD8 (HIV-CD8) cells but varying degrees of CD4 (HIV-CD4) cell destruction. However, no measurable viral p24 antigen was produced extracellularly. On the other hand, when the purified HIV-CD4 cells were similarly activated, no such cell death was noted and high titer p24 was detected in the culture supernatants. Addition of exogenous IL-2 to either HIV-PBMC or HIV-CD4 cultures, did not alter either CD4 cell death or HIV-1 p24 production. Isolated HIV-CD8 killed not only HIV-CD4 but also nCD4, when co-cultured and less proliferative fractions of CD4 cell population was the more preferred targets of the HIV-CD8 CTL activity. The presence of anti-CD4 CTL activity was closely associated with high CD8, but not with CD4 counts, of the HIV+ patients.

CD4 Lymphocyte Count↗
PubMed1995

Suppressed proliferative response and interleukin-2 production in hispanic HIV+ and AIDS T-cell subsets.

We find that interleukin-2 (IL-2) production is severely depressed (80-90%) in AIDS T-cells (CD4+ or CD8+) stimulated with anti-CD3 or Con A together with phorbol ester (PMA) or anti-CD28 coactivation. Likewise, the proliferative response of CD4+ T-cells was suppressed, from a mean of 24.6% (HIV+) to 59.1% (AIDS) for PMA with activators OKT3 (anti-CD3), Con A, enterotoxin B or pokeweed mitogen, and 20.2% (HIV+) to 77.8% (AIDS) with anti-CD28 co-activation. Similar degrees of suppression were found with the CD8+ T-cells except for a much greater suppression at the HIV+ stage with anti-CD28 (57.7%), approximately 2.5 times higher than for PMA coactivation. However, when proliferation was induced by the two coactivators combined (PMA plus anti-CD28), much less suppression was observed: 8.5% (HIV+) to 19.0% (AIDS) for CD4+ cells and 8.2% to 26.5%, respectively, for CD8+ cells. The data suggest that during HIV infection the CD28 pathway becomes most defective, but can be bypassed to some extent by the less-impaired PMA pathway. The IL-2 (+PMA) signal in HIV+ and AIDS cells was also significantly less suppressed suggesting that the disregulation in HIV infection is more prominent prior to the IL-2 stage of the mitogenic pathway. It is remarkable that the CD4+ and CD8+ T-cells at both the HIV+ and AIDS stages generally show the same degree of suppression with all the various activators and coactivators used.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1995

N-acetylcysteine (NAC) enhances interleukin-2 but suppresses interleukin-4 secretion from normal and HIV+ CD4+ T-cells.

We find that purified CD4+ T cells from 30 HIV+ individuals have a suppressed Interleukin-4 (IL-4) production compared to normal controls regardless of activator (anti-CD3 or Con A) or co-activator [phorbol ester (PMA or anti-CD28)], generally by 2-4 fold. In every case, the cells producing IL-4 respond more strongly to anti-CD28 co-activation than to PMA, ie, 1150 pg/ml compared to 2070 pg/ml for controls and 398 pg/ml compared to 1250 pg/ml for HIV+ cells, respectively. In contrast, anti-CD3 with PMA gives a more vigorous IL-2 response than with anti-CD28, ie, 37.3 ng/ml compared to 12.3 ng/ml for controls and 28.5 ng/ml versus 15.1 ng/ml for HIV+ cells, respectively. These data are not compatible with the TH1/TH2 switch hypothesis since IL-4 production is decreased, not increased for CD4+ HIV+ T-cells and while IL-2 production is decreased with PMA, it is not decreased significantly with anti-CD28. Interestingly, 5 mM N-acetylcysteine (NAC) acts as an immunoenhancer; mitogenesis was enhanced 2 fold or more in general for control and HIV+ CD4+ T-cells and IL-2 production was enhanced 2-3 fold for anti-CD3 (with PMA or anti-CD28) for both controls and HIV+ CD4+ cells. However, NAC suppressed IL-4 production induced by anti-CD3 and anti-CD28 in both control and HIV+ CD4+ T cells. In the other cases, it produced in general no significant change.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcysteine↗
PubMed1994

Activated Ki-Ras complements erythropoietin signaling in CTLL-2 cells, inducing tyrosine phosphorylation of a 160-kDa protein.

We have previously shown that expression of erythropoietin (EPO) receptor (EPOR) alone failed to confer EPO responsiveness on the interleukin 2-dependent T-cell line CTLL-2, whereas the introduction of the EPOR into interleukin 3-dependent pro-B-cell lines, such as BAF-B03, allowed the cells to proliferate in response to EPO. Here, we report that additional expression of v-Ki-Ras conferred EPO-dependent growth on CTLL-2 cells expressing the EPOR, with additional formation of a high-affinity EPOR. To investigate possible mechanisms of EPOR downstream signaling induced by v-Ki-Ras expression in these CTLL-2-derived cells, we carried out anti-phosphotyrosine immunoblot analysis of the EPOR complex immunoprecipitated with anti-EPOR antibody from lysates of cells with and without cytokine stimulation, revealing two 160-kDa and 130-kDa phosphotyrosyl proteins. An anti-JAK2 antibody did not react with these proteins, suggesting that they may represent cellular components involved in an EPO-EPOR signaling pathway induced by v-Ki-Ras. Similar phosphotyrosyl proteins were present among Friend erythroleukemia cell lines, in which the Friend virus gp55/EPOR complex on the cell surface constitutively sends signals for cell growth.

Cell Division↗
PubMed1994

Milk transfer and tissue uptake of mercury in suckling offspring after exposure of lactating maternal guinea pigs to inorganic or methylmercury.

Maternal guinea pigs were injected with mercuric chloride (HgCl2; 1 mg Hg/kg body weight) or methylmercury (MeHg; 1 mg Hg/kg) 12 h after parturition, and exposure of the offspring to mercury (Hg) via breast milk were studied on days 3, 5 and 10 postpartum. Milk Hg concentrations were lower than maternal plasma Hg concentrations regardless of the form of Hg given to the dams. Milk Hg was higher in HgCl2-treated dams than in MeHg-treated dams. In MeHg-treated dams, MeHg was separately determined. While the ratio of MeHg to T-Hg decreased in the dams' plasma, it did not in the milk. There was a strong correlation between milk and plasma T-Hg concentrations in HgCl2 treated dams. In the milk of MeHg-treated dams, the plasma MeHg concentrations correlated better than did the plasma T-Hg concentrations. In the offspring, regardless of the chemical forms of Hg given to the dams, the highest Hg concentrations were found in the kidney, followed by the liver and the brain. Brain Hg concentrations were, however, significantly higher in the offspring of MeHg-treated dams than in those of HgCl2-treated dams. In addition, Hg levels in the major organs of the offspring of HgCl2-treated dams peaked on day 5 postpartum, while those of MeHg-treated dams did not show a significant decrease up to day 10 postpartum. These facts indicate that the two chemical forms of Hg were transferred to the offspring via the breast milk and were distributed differently, depending on the chemical form, to the offspring's tissues.

Animals↗
PubMed1994

Local secretion of corticotropin-releasing hormone by enterochromaffin cells in human colon.

BACKGROUND/AIMS: Corticotropin-releasing hormone (CRH) is a regulator of the hypothalamic-pituitary-adrenal axis and a coordinator of the gastrointestinal response to stress. In addition to its central effects, CRH has peripheral effects on the immune system. CRH is present in several human tissues, such as the brain, spinal cord, adrenal medulla, lung, liver, peripheral blood leukocytes, as well as the gastrointestinal tract. The current study examined the local production of CRH in the normal human colon. METHODS: Normal human colonic tissues obtained by endoscopic biopsy were immunostained with anti-CRH and anti-5-hydroxytryptamine antibody and analyzed for CRH messenger (m)RNA by a reverse-transcribed polymerase chain reaction method and by in situ hybridization. RESULTS: Immunoreactive CRH and CRH mRNA were detected in the colonic mucosal cells in the neighborhood of the base of the crypts. The mucosal cells that expressed CRH mRNA also immunostained with anti-5-hydroxytryptamine antibody. CONCLUSIONS: Normal human colonic mucosal enterochromaffin cells produce CRH. CRH in the colonic mucosa may play a role in the modulation of the intestinal immune system and/or other gastrointestinal functions basally during stressful conditions.

Adolescent↗
PubMed1994

Recombinant human granulocyte colony-stimulating factor augments cytotoxicity of OK-432-induced polymorphonuclear leukocytes.

Polymorphonuclear leukocytes (PMNs) recovered from the peritoneal cavity of mice treated with the streptococcal preparation OK-432, exhibited strong cytotoxicity after the in vitro addition of Nocardia rubra cell wall skeleton (N-CWS). In this study, we investigated whether recombinant human granulocyte colony-stimulating factor (rhG-CSF) could augment the cytotoxicity of OK-432-induced PMNs after the addition of N-CWS in vitro. PMNs recovered from the peritoneal cavity of 8- to 10-week-old, male C3H/He mice induced by intraperitoneal (i.p.) injection of 50 KE/kg (1 KE = 0.1 mg) of OK-432 were used in a 51Cr release assay against MM46 mammary carcinoma cells. While addition of rhG-CSF in vitro did not augment the cytotoxicity of OK-432-induced PMNs, marked augmentation of the cytotoxicity of OK-432-induced PMNs was observed following a single subcutaneous (s.c.) or i.p. injection of 125 micrograms/kg of rhG-CSF. The effect of in vivo administered rhG-CSF was dependent on the timing of the injection with respect to OK-432 administration and differed from s.c. or i.p. injections. Interestingly, the cytotoxicity of OK-432-induced PMNs was rather weak following consecutive s.c. or i.p. administration of rhG-CSF for 7-14 days. H2O2 is likely involved in mediating the cytotoxicity of OK-432-induced PMNs since activity was significantly reduced by the in vitro addition of low concentration of catalase. Generation of H2O2 by the PMNs correlated with cytotoxicity. These results suggest that in vivo administration of rhG-CSF augments the cytotoxicity of OK-432-induced PMNs in a time dependent fashion and that H2O2 plays an important role in mediating their cytotoxicity.

Animals↗