Search PubMed⌕ Search

Biomedical subjects

M Niimi

Publications and source records attributed to M Niimi.

At least 109 records · Page 6Linked to original sources
PubMed1997

Temperature-related expression of the vacuolar aspartic proteinase (APR1) gene and beta-N-acetylglucosaminidase (HEX1) gene during Candida albicans morphogenesis.

Expression of the Candida albicans vacuolar aspartic proteinase (APR1) and beta-N-acetylglucosaminidase (HEX1) genes was studied when carbon-starved cells of strains ATCC 10261 and A72 were induced to grow as yeast or as germ tube-forming cells. Amounts of APR1 mRNA were similar under yeast or germ tube growth conditions. However, more APR1 mRNA was present in cells grown at 28 degrees C than in cells grown at 37 degrees C. The Apr1 enzyme activity of cell-free extracts was not affected by cellular morphology, culture pH or growth temperature. Amounts of HEX1 mRNA were also higher in N-acetylglucosamine (GlcNAc)-induced cells grown at 28 degrees C than in cells grown at 37 degrees C. There was slightly more HEX1 mRNA in cells grown at pH 4.5 than in cells grown at pH 6.7. The beta-N-acetylglucosaminidase activities of GlcNAc-grown cells correlated with the amounts of HEX1 mRNA and were higher when cells were grown at a lower temperature and at a lower pH. Although a similar temperature- and pH-dependent pattern of HEX1 mRNA expression was seen in cells grown on glucose, the enzyme activities in cell-free extracts were all very low. These data indicate that the APR1 and HEX1 genes play no direct role in the dimorphic transition of C. albicans and that transcription of both genes appears to be temperature regulated when the cells are released from carbon starvation. The expression of HEX1 mRNA is in part under the control of culture pH and translation of HEX1 mRNA seems to be regulated by glucose.

Acetylglucosaminidase↗
PubMed1997

Regulation of N-acetylglucosaminidase production in Candida albicans.

The N-acetylglucosaminidase of Candida albicans is a secreted hydrolytic enzyme that contributes to the yeast's virulence. There was a significant increase in the N-acetylglucosaminidase activity of C. albicans cells released from carbon starvation in medium containing N-acetylglucosamine. The increased enzyme activity in N-acetylglucosamine-grown cells correlated with increased transcription of the HEX1 gene, which encodes C. albicans N-acetylglucosaminidase. In contrast, glucose repressed HEX1 transcription, and glucose-grown cells had on average 94-fold lower N-acetylglucosaminidase activities than did N-acetylglucosamine-grown cells. N-acetylglucosaminidase induction in cells grown on N-acetylglucosamine was also repressed by fructose, mannose or galactose, although to a lesser extent than by glucose, and sucrose repressed enzyme production by only 10%. Eighty-eight percent of the enzyme in N-acetylglucosamine-grown cells was localised in the periplasm, and after incubation for 5 h, 30 or 70% of the total enzyme activity was secreted into the medium by yeast or mycelial cells, respectively. The cellular location of the enzyme and the regulation of production by the carbon source indicate a scavenging role for C. albicans N-acetylglucosaminidase.

Acetylglucosamine↗
PubMed1997

Lipopolysaccharide and interleukin-1beta augmented histidine decarboxylase activity in cultured cells of the rat embryonic brain.

We investigated the effect of lipopolysaccharide (LPS) and various inflammatory cytokines on the histidine decarboxylase (HDC) activity in cultured cells of the rat embryonic brain. Histaminergic neuronal cell bodies were supposed to exist in cultured cells of the diencephalon but not in those of the cortex. The HDC activity was elevated by adding LPS and interleukin-1 beta (IL-1beta) but not by tumor necrosis factor-alpha (TNF-alpha) and IL-6 to the mixed primary cultures of diencephalon. In the adherent cell fraction of the cultured diencephalon cells, HDC activity was also enhanced by LPS and IL-1beta. In a similar manner, LPS augmented HDC activity in the mixed primary culture of cerebral cortical cells and in its adherent cell fraction. The effects of IL-1beta but not LPS in the mixed primary culture of diencephalon were canceled by a prior exposure to cytosine-beta-D-arabinofuranoside. The changes in HDC activity after exposure to LPS for 12 h were not accompanied by increased mRNA levels. In these cell cultures, mast cells were not detected by Alcian Blue staining. These results indicated the presence of the third type of HDC-bearing cell besides neurons and mast cells in the brain. The increase of HDC activity by IL-1beta might be due to cell proliferation.

Animals↗
PubMed1997

Effect of continuous intravenous injection of interleukin-6 and pretreatment with cyclooxygenase inhibitor on brain c-fos expression in the rat.

The aim of the present study was to assess potential brain sites of stimulation by peripheral interleukin (IL)-6 of the hypothalamo-pituitary-adrenal (HPA) axis in the rat, using c-fos protein as a marker of cellular activation. Involvement of prostaglandins in IL-6-induced ACTH secretion and c-fos expression was also investigated. IL-6 was infused continuously (40 ng/min) for 90 min to conscious male rats. Blood samples were taken before the infusion and at 30 and 90 min for measurement of plasma ACTH. Expression of c-fos in the brain was examined by immunohistochemistry. Administration of IL-6 significantly elevated plasma ACTH levels at 30 min (495 +/- 105 vs. 117 +/- 17 pg/ml in controls, p < 0.05). Elevated levels were still present at 90 min (596 +/- 139 vs. 113 +/- 20 pg/ml in controls, p < 0.05). Infusion of IL-6 (3.6 micrograms/rat) markedly triggered c-fos expression in hypothalamic paraventricular (PVN) and supraoptic nuclei (SON), as well as in the central amygdaloid nucleus (CeA), the nucleus tractus solitarius and the locus coeruleus. Pretreatment with the cyclooxygenase inhibitor indomethacin (10 mg/kg, i.v.) suppressed the ACTH response induced by IL-6. The number of IL-6-induced immunoreactive cells in the PVN was significantly reduced by indomethacin pretreatment (p < 0.01), but the number of IL-6-induced c-fos-positive cells in the SON and CeA remained unchanged. These findings suggest that circulating IL-6 may exert central actions by acting directly or indirectly on brain neurons. In addition, the ability of IL-6 to activate the HPA axis may depend upon the release of prostaglandins, probably in the brain.

Adrenocorticotropic Hormone↗
PubMed1997

Effects of short- and long-term dexamethasone treatment on growth and growth hormone (GH)-releasing hormone (GRH)-GH-insulin-like growth factor-I axis in conscious rats.

Although the inhibitory effects of a chronic excess of glucocorticoids (GC) on body growth and GH secretion are well established, the mechanisms involved remain unclear. In this study, we examined the chronic effects of a high dose of dexamethasone (DEX) on spontaneous GH secretion and insulin-like growth factor (IGF)-I in conscious rats. The animals were given daily i.p. injections of DEX (200 microg/day) for either one or four weeks. Body growth assessed by tibia length and serum IGF-I levels was significantly inhibited 1 week after treatment. By contrast, spontaneous GH secretion was not altered 1 week after the treatment. Neither hypothalamic GRH and somtatostain mRNA levels nor GH responses to GRH from single somatotropes were affected 1 week after the treatment. Four weeks after DEX treatment, body growth of the rats was noticeably suppressed. Interestingly, spontaneous GH secretion, hypothalamic GRH mRNA levels and GH responses to GRH were all inhibited 4 weeks after treatment. Pituitary GRH receptor mRNA levels were not altered 1 week after treatment, but increased after 4 weeks. These results indicate that a high dose of DEX initially impairs IGF-I production and subsequently inhibits spontaneous GH secretion in rats. Inhibition of spontaneous GH secretion resulting from chronic GC excess is due, at least in part, to the impairment of hypothalamic GRH synthesis and pituitary GH responsiveness. An increase in the pituitary GRH receptor may be caused by decreased GRH secretion.

Animals↗
PubMed1997

[Assessment of reproducibility and unidimensionality of International Prostate Symptom Score Japanese version].

BACKGROUND: International Prostate Symptom Score (IPSS), which is a self-administered questionnaire consisting of 7 questions with 6 categories, has been used in many countries as the standard scale of subjective urinary symptoms of patients with prostatism. In Japan, although we have already used the Japanese version at daily clinical situations, the reproducibility and validity of it have never been examined. We tried to assess the reproducibility and unidimensionality of the questionnaire. PATIENTS AND METHODS: 64 out-patients with benign prostatic hyperplasia were asked to fill the self-administered questionnaires, first at the hospital, and second at home. RESULTS: The weighted kappa statistics were low in almost all the items (0.10-0.75), so the reproducibility was evaluated to be poor. For as reasons, it was suggested that understandings of Japanese translation and recognition of frequency about chronic urinary symptoms were difficult for the respondents. The results of principal component analysis showed that the item for nocturia measures a different aspect from what the other items measured. So the unidimensionality of the scale was also not confirmed. CONCLUSION: These results suggested that IPSS Japanese version should be further modified, especially on its Japanese translation, and then the unidimensionality should be examined again.

Aged↗
PubMed1997

[The physical, mental and social impacts of telling prostate cancer patients the true diagnosis].

BACKGROUND: Telling cancer patients the true diagnosis is inevitable to acquire informed consent especially in the Western world. In Japan, however, no such consensus has been established yet. We investigated the influence of telling the true diagnosis on QOL of prostate cancer patients. METHODS: We measured physical, mental and social aspect of prostate cancer outpatients by the General Health Questionnaire (GHQ) and the international Prostate Symptom Score (I-PSS). Using the general linear models we tried to explore which variables would attribute to "severe depression", "anxiety and insomnia" and "social dysfunction". RESULTS: No significant differences were found in any of the eight variables (age, performance status, clinical stage, I-PSS and Goldberg's four factors of GHQ) among the two groups that were informed the true diagnosis or not. The correlation structures of "severe depression", "somatic symptoms" and I-PSS are significantly different in the two groups. As a result of the analysis by the GLM, "somatic symptoms", I-PSS and clinical stages had main effect on "severe depression". Also, there was an interaction between the effect of telling the true diagnosis and "somatic symptoms". CONCLUSION: These results suggest that the mental condition of prostate cancer patients remain stable when they are in good physical condition regardless of being informed the true diagnosis or not. However, the patients who weren't told the true diagnosis have a tendency to get depression accompanying deterioration of physical condition. It is therefore considered that telling the true diagnosis makes the patients understand the changes of their physical conditions and help their mind to be stable.

Aged↗
PubMed1996

Identification of bovine invariant chain (Ii) gene by nucleotide sequencing.

Four overlapping cDNA clones encoding the bovine invariant chain (Ii) were isolated and characterized. The bovine Ii cDNA clone, NI3 with a 1,381-bp insert, encoded a translated product of 204 amino acids. The amino acid sequences deduced from this clone revealed that the bovine Ii gene is more closely related to human Ii gene than to genes for rodents, such as mouse and rat, but lacked 10 amino acids of the 3' end of the extracellular domain comparable to those in proteins from other species. Of interest is that the class-II-associated invariant chain peptide (CLIP) segment is present in the protein encoded by NI3, and this region exhibits a high degree of overall similarity to sequences encoded by human, mouse and rat, suggesting that bovine CLIP may have the biological function of CLIP binding to MHC class II molecules. Thus, it seems likely that this cDNA clone encodes a functional product which might perform an important function in MHC class II antigen presentation, as previously established in studies in mouse and man.

Amino Acid Sequence↗
PubMed1996

Semi-allogeneic (F1) versus fully allogeneic blood transfusions: differences in their ability to induce specific immunological unresponsiveness.

The beneficial effect on graft survival achieved by pretransplant blood transfusions is well established. However, the type of major histocompatibility complex (MHC) mismatch between transfusion donor and recipient seems to play a role in determining the outcome. The hypothesis that this sharing of MHC antigens is correlated with the level of sensitization or tolerization was studied in mice by pretreatment with semi-allogeneic (F1) or with fully allogeneic whole blood transfusions. Limiting dilution analysis (LDA) in vitro for donor-specific T helper (Thp) and cytotoxic T lymphocyte precursors (CTLp) performed on splenocytes isolated from transfused recipients 2 or 4 weeks after transfusion showed that the duration and magnitude of the response was reduced after a semi-allogeneic compared to a fully allogeneic transfusion. After a semi-allogeneic transfusion, both Thp and CTLp frequencies had returned to naive levels 4 weeks after transfusion, whereas after infusion of fully allogeneic blood, they remained elevated after 4 weeks. When a fully allogeneic heart was transplanted 2 or 4 weeks after transfusion, a small but significant improvement in graft prolongation (2 weeks, not significant, 4 weeks: p < 0.01) was observed following pretreatment with a semi-allogeneic transfusion (2 weeks: median survival time (MST) 30 days, 4 weeks: MST 29 days) compared to that obtained after fully allogeneic transfusion (2 weeks: MST 23 days, 4 weeks: MST 12 days). The semi-allogeneic transfusions were correlated with a statistically significant prolonged (7 days) persistence of donor-derived MHC class II+ cells in the recipient and with reduced levels of anti-donor MHC class I-specific antibody formation compared to these responses after transfusion with fully allogeneic cells. These results demonstrate that pretreatment with a semi-allogeneic blood transfusion is more tolerizing and less sensitizing than pretreatment with a fully allogeneic blood transfusion. These findings may be explained by the sharing of MHC antigens between recipient and transfusion donor.

Animals↗
PubMed1996

Dibutyryl cyclic AMP-enhanced germ tube formation in exponentially growing Candida albicans cells.

Competence in germ tube formation for exponential phase cells of several Candida albicans was low (less than 14%) in 0.1 M phosphate buffer (pH 6.8) containing 1 mM proline. Addition of 5 mM dibutyryl cyclic AMP (cAMP), a lipophilic cAMP analog, to the induction medium increased germ tube formation up to 50%. This enhancement occurred only when the cells were grown in medium lacking glucose or fructose as a carbon source. N-Acetylglucosamine-induced germ tube formation was enhanced by dibutyryl cAMP under similar conditions, but the enhancement was only slight. Cyclic GMP (cGMP) or AMP did not enhance germ tube formation, while dibutyryl cGMP, theophylline, and butyric acid were inhibitory. These results show that dibutyryl cAMP stimulation of the germ tube formation depends on the growth phase and the nutritional status of the cell.

Bucladesine↗
PubMed1996

Differential profiles of soluble proteins during the initiation of morphogenesis in Candida albicans.

Candida albicans is a dimorphic fungus that can grow either as yeast or as mycelia. The mycelial form may be required for tissue penetration and therefore may have a role in pathogenesis. The protein profiles of the cell-free S100 fraction from budding yeast cells and germ tube-forming cells (an early stage of the transition between yeast and mycelia) were evaluated using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Yeast growth or germ tube formation was induced in carbon-starved cells at 37 degrees C by either glucose, galactose or N-acetylglucosamine at pH 4.5 or pH 6.7. More than 400 constitutively synthesised polypeptides were identified on 2-D PAGE by silver staining. A few polypeptides which seem to reflect the release from carbon starvation were detected, but no polypeptides unique to either morphology were observed. Fractionation of S100 preparations by polyethylenimine or heparin-agarose affinity chromatography, which have been used to detect DNA-binding proteins, revealed several proteins that were synthesised on the resumption of cell growth or in response to pH difference. Heparin-agarose also bound novel polypeptides in the size range 130-200 kDa that were preferentially synthesised in germ tube-forming cells. These results suggest that any protein factors that might exert a regulatory role early in germ tube formation are of low abundance, and that a minor group of soluble proteins involved in C. albicans morphogenesis may be differentially synthesised.

Acetylglucosamine↗
PubMed1996

Multiple efflux mechanisms are involved in Candida albicans fluconazole resistance.

Fluconazole-susceptible Candida albicans strains accumulated [3H]fluconazole at a rate of approximately 2 pmol/min per 10(9) cells. Fluconazole accumulation was not affected by the pretreatment of cells with sodium azide or with 2-deoxyglucose. The rate of fluconazole accumulation became saturated at high fluconazole concentrations and was not affected by the addition of ketoconazole, and there was no fluconazole accumulation in cells incubated at 4 degrees C. A fluconazole-resistant mutant of C. albicans SGY-243 was isolated following growth enrichment in fluconazole-containing medium. Cells of the mutant strain, designated FR2, showed a reduced rate of fluconazole accumulation compared with SGY-243 and were not resistant to other azole antifungal agents. The rates of fluconazole accumulation by C. albicans FR2 and the other azole-resistant strains, B59630, AD, and KB, were increased in the presence of sodium azide, suggesting that fluconazole resistance in these strains may be associated with an energy-dependent drug efflux. Fluconazole-resistant C. albicans strains all contained elevated amounts (2- to 17-fold) of mRNA encoding Cdr1, and an ATP-binding cassette-type transporter. In addition, C. albicans FR2 also contained increased amounts of mRNA encoding Benr, a major facilitator superfamily transporter. These results suggest that fluconazole enters C. albicans cells by facilitated diffusion and that fluconazole resistance may involve energy-dependent drug efflux associated with increased expression of Benr and/or Cdr1.

Antifungal Agents↗
PubMed1996

Cumulative incidence and prevalence of childhood autism in children in Japan.

BACKGROUND: An epidemiological survey of childhood autism as defined in ICD-10 Research Criteria was conducted in the northern part of Yokohama, Japan. METHOD: The routine health checkup for 18-month-old children served as the initial mass-screening, and all facilities which provide child care services function to detect all cases with childhood autism and refer them to the Yokohama Rehabilitation Centre. RESULTS: Cumulative incidence of childhood autism up to 5 years of age among the birth cohort of 1988, and prevalence on 1 January 1994, among residents born in 1988 were estimated RESULTS: Cumulative incidence and prevalence were 16.2 per 10,000 and 21.1 per 10,000, respectively. Children with high-functioning autism who had IQs of 70 and over constituted approximately half of all the children with childhood autism. CONCLUSION. It was confirmed through better detection of high-functioning cases that childhood autism in Japan is more common than formerly estimated.

Age Factors↗
PubMed1996

Immunosuppressant agent FK506 stimulates growth hormone (GH) secretion and gene expression of hypothalamic GH-releasing hormone in the rat.

Immunosuppressant agent FK506 has been reported to stimulate ACTH release from pituitary cells. We examined the effects of FK506 on GH release from the rat anterior pituitary cells and the effects of FK506 on hypothalamic GH- releasing hormone (GRH) and somatostatin (SS) gene expression in conscious male rats. In vitro experiments, the monolayer pituitary culture and reverse hemolytic plaque assay were employed to examine the GH release from the rat anterior pituitary cells. In in vivo experiments, the FK506 was administered for 7 days and then sequential blood sampling was performed every 20 min during 6 h in conscious rats. The hypothalamus was removed, and total RNA was extracted for Northern blot analysis. The FK506 significantly stimulated GH release from the rat anterior pituitary cells in a dose-dependent manner in vitro. In in vivo experiments, the area under the curve of GH surges was significantly increased in FK506-treated rats, although the peak height and the trough level of GH surges were not altered. Pituitary GH messenger RNA (mRNA) levels were significantly increased by the FK506 treatment. Hypothalamic GRH mRNA levels were significantly increased in FK506- treated rats, whereas hypothalamic SS mRNA levels were not altered. These findings indicate that FK506 stimulates GH secretion and gene expression of hypothalamic GRH in the rat.

Animals↗
PubMed1996

Nitrite/nitrate (NOx) and sFas antigen levels in patients with multiple organ failure.

We assessed the plasma levels of nitrite/nitrate (NOx) and soluble Fas antigen (sFas) in patients with multiple organ failure (MOF). The NOx levels showed high levels in MOF patients with sepsis and without infection. A significant difference was not seen between the MOF patients complicated by sepsis and uncomplicated by infection, although the NOx levels in the former group tended to be higher. There was a significant correlation between NOx levels and sFas levels in MOF patients. Both sFas and NOx levels were high during MOF, and rapidly decreased when MOF was relieved. These findings suggest that sFas and NOx contribute to the development of MOF.

Humans↗
PubMed1996

Functional modification of vascular endothelial cells by cytokines during septic shock.

The function of vascular endothelial cells is to adjust blood vessel tonus, which contributes to maintaining homeostasis within blood vessels. However, inflammatory cytokines are produced in response to invasion by stimulating vascular endothelial cells and sometimes lead to shock or multiple organ failure. In the present study, we assessed cytokines in sepsis and septic shock, and various factors that are said to have a damaging effect on vascular endothelium. Endotoxin was measured by endotoxin-specific methods. Tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), and interleukin 8 (IL-8) were measured by enzyme-linked immunosorbent assay (ELISA). Endothelin-I was measured by radioimmunoassay (RIA). Nitric oxide was measured as metabolites of nitrite and nitrate oxides (NOx) by a method based on the Griess method. Thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (PGF 1 alpha) were both measured by RIA. All of the factors except endotoxin were significantly higher in the septic shock group than in the non-shock group and significantly higher in the non-survivor group than in the survivor group. Significant correlations were also found between endothelin-1 and NOx and between TXB2 and PG1 alpha. Significant correlations were also found between TNF-alpha and IL-6, endothelin-1, NOx and TXB2, but no significant correlations were detected between any of them and endotoxin. In serious diseases such as septic shock, the vascular endothelial constricting factors, endothelin and TXB2, and the blood vessel relaxing factors NOx and PGF1 alpha increase almost simultaneously. This suggests that the body's regulating mechanisms are disrupted in these serious conditions. The results of this study also suggest that inflammatory cytokines may be involved in stimulating the production of these factors.

Adult↗
PubMed1995

Nucleotide sequences and the molecular evolution of the DMA and DMB genes of the bovine major histocompatibility complex.

cDNA clones encoding the bovine major histocompatibility complex (MHC) class II DM alpha- and beta-chains were isolated and characterized. The BoLA-DMA cDNA clone, MA7, encoded a primary translated product of 260 amino acids, which included a signal peptide of 26 amino acids and a mature polypeptide of 234 amino acids. The BoLA-DMB cDNA clone, MB6, encoded a primary translated product of 262 amino acids, with a signal peptide of 18 amino acids and a mature polypeptide of 244 amino acids. Comparison of the sequences and construction of a phylogenetic tree revealed that both clones are more closely related to human and mouse DM genes than to genes for conventional bovine class II alpha- and beta-chains. Thus, since the bovine DMA and DMB genes are so different from other class II sequences and show evidence of strong conservation (> 70%) among the bovine, mouse and human homologues, it seems likely that each of these cDNA clones encodes a functional product, which might perform an important function, as previously established in studies in mouse and man.

Amino Acid Sequence↗