Biomedical subjects

M Yamamura

Publications and source records attributed to M Yamamura.

At least 73 records · Page 4Linked to original sources

PubMed1997

Effect of cyclic polylactates on tumor cells and tumor bearing mice.

We studied the effect of cyclic polylactates ranging in size from a degree of polymerization number of 3 to 13 on pyruvate kinase, lactic dehydrogenase, anaerobic glycolysis, growth of tumor cells and survival of tumor bearing mice. Pyruvate kinase and lactic dehydrogenase activities were both inhibited by cyclic polylactates, and the inhibition mechanism of cyclic polylactates on lactic dehydrogenase was noncompetitive. About half the anaerobic glycolytic activity of FM3A ascites tumor cells was inhibited and tumor cell growth was also effectively inhibited by cyclic polylactates. Mice, which were treated with cyclic polylactates after inoculation of FM3A ascites tumor cells lived significantly longer than mice, which were treated with vehicle or non mice.

Anaerobiosis↗

PubMed1997

Detection of herpes simplex DNA in semen and menstrual blood of individuals attending an infertility clinic.

OBJECTIVE: To determine a possible link between herpes simplex virus 1 (HSV) and infertility. METHOD: A specifically designed polymerase chain reaction with nested primers, was developed and used to test for HSV in 153 men and 20 women attending an infertility clinic. RESULTS: HSV DNA was detected in 37 (24%) out of 153 semen samples and in 11 (55%) out of 20 menstrual blood samples. However, HSV DNA (0%) was not detected in the semen of 16 males with children. A significant association between the evidence for infertility and an HSV positive test was observed in men (Fisher's exact test, p = 0.024), and a stronger effect was found in females after failed in vitro fertilization (Fisher's exact test p = 0.0086). CONCLUSION: This is the first report of the detection of herpes simplex virus DNA in semen and menstrual blood. Encouraging preliminary results justify antiviral therapy in case of a positive test.

Acyclovir↗

PubMed1997

Leukocytapheresis with leukocyte removal filter as new therapy for ulcerative colitis.

Leukocytapheresis (LCAP) with a leukocyte removal filter column was administered for 45 patients with ulcerative colitis (UC). We evaluated changes in the leukocyte count and the differential percentages during LCAP. Cytokine production was assessed from each patient's peripheral mononuclear cells or monocytes. Flow cytometry was performed to assess the removal rates of activated cells and adhesion molecule positive cells by LCAP. Clinical improvement was recognized in 35 of 45 patients during intensive LCAP therapy, and it continued throughout maintenance therapy in 32 patients (71.1%). The leukocyte count was decreased to about 40% during the first 30 min, but it increased to approximately 170% at 20 min after the completion of LCAP. The concentration of tumor necrosis factor (TNF)alpha before LCAP in the effective group was higher than it was in either the ineffective group or the control group. Its level decreased to near normal range after LCAP. In the effective group, the concentrations of interleukin (IL)-1beta, IL-2, interferon (IFN)gamma, and IL-8 were near the normal upper limits before LCAP; however, they had decreased after LCAP. The concentration of IL-4 increased after LCAP. In the ineffective group, in contrast, the concentrations had been at or near normal before the initial LCAP treatment. Flow cytometry study revealed that LCAP could remove the activated cells and adhesion molecule positive cells more effectively. The clinical improvement and the changes observed before and after LCAP therapy suggest that LCAP is able to intervene in the causal mechanism(s) of UC.

Blood Cell Count↗

PubMed1997

Construction of a starch-utilizing yeast by cell surface engineering.

We have engineered the cell surface of the yeast Saccharomyces cerevisiae by anchoring active glucoamylase protein on the cell wall, and we have endowed the yeast cells with the ability to utilize starch directly as the sole carbon source. The gene encoding Rhizopus oryzae glucoamylase with its secretion signal peptide was fused with the gene encoding the C-terminal half (320 amino acid residues from the C terminus) of yeast alpha-agglutinin, a protein involved in mating and covalently anchored to the cell wall. The constructed plasmid containing this fusion gene was introduced into S. cerevisiae and expressed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter from S. cerevisiae. The glucoamylase activity as not detected in the culture medium, but it was detected in the cell pellet fraction. The glucoamylase protein transferred to the soluble fraction from the cell wall fraction after glucanase treatment but not after sodium dodecyl sulfate treatment, indicating the covalent binding of the fusion protein to the cell wall. Display of the fused protein was further confirmed by immunofluorescence microscopy and immunoelectron microscopy. The transformant cells could surely grow on starch as the sole carbon source. These results showed that the glucoamylase was anchored on the cell wall and displayed as its active form. This is the first example of an application of cell surface engineering to utilize and improve the metabolic ability of cells.

Cell Membrane↗

PubMed1997

Chronic anti-ataxic actions of the novel thyrotropin-releasing hormone (TRH) analog, TA-0910, during and after repeated administration in Rolling mouse Nagoya: behavioral and pharmacokinetic studies.

Anti-ataxic effects of TA-0910, a novel thyrotropin-releasing hormone analog, in mice of the ataxic mutant mouse strain Rolling mouse Nagoya (RMN) are sustained beyond its 2-week oral administration period (Kinoshita et al., Eur. J. Pharmacol., 274, 65-72, 1995). We examined the concentration of TA-0910 in the central nervous system (CNS) of RMN after repeated administration in an attempt to clarify the mechanism of the sustained effect of the drug. Repeated administration of TA-0910 (3 mg/kg/d, i.p.) for 2 weeks produced a long-lasting ameliorating effect on ataxia in RMN, and this effect was maintained until 3 weeks after drug withdrawal. The concentrations of TA-0910 in the cerebrum and brain stem 24 h after the final administration were twice the concentration observed 24h after single administration. The cerebellum cencentration of TA-0910 was more than 4 times that observed 24 h after final administration. After repeated administrations, the drug concentrations in the brain tissues gradually decreased, but the drug was still detectable in the cerebrum and brain stem 3 weeks after withdrawal. However, these concentrations of TA-0910 3 weeks after withdrawal were as low those observed 24 h after single administration when there were no anti-ataxic effects. These observations suggest that the long-lasting ameliorating effect on the ataxia during and after repeated administration of TA-0910 is not ascribable to the drug remaining in the CNS of RMN.

Animals↗

PubMed1997

Distribution of thyrotropin-releasing hormone (TRH) receptors in the brain of the ataxic mutant mouse, rolling mouse Nagoya.

Thyrotropin-releasing hormone (TRH) and its analog, TA-0910, ameliorate the ataxia of the mutant mouse, rolling mouse Nagoya, by metabolic normalization in the ventral tegmental field (VTF). We here investigated the distribution of cerebral TRH receptors in the rolling mouse to clarify the sites of action of these drugs. TRH receptors were widely distributed in multiple brain areas, including in the VTF and the cuneiform nucleus (CnF) which terminates in the VTF. These results suggest that TRH and TA-0910 directly activate the VTF by acting on TRH receptors in the VTF and indirectly activate it through the receptors in the CnF.

Animals↗

PubMed1997

[Synthesis and pharmacological action of TRH analog peptide (Taltirelin)].

Taltirelin hydrate[1-methyl-(S)-4,5-dihydroorotyl-L-histidyl-L-prolineamide tetrahydrate] is a new orally active thyrotropin releasing hormone (TRH) peptide analog synthetized from aspartic acid. From preclinical studies with mice and rats, Taltirelin hydrate was found to be highly stable in the blood and brain as compared with TRH. Furthermore, the CNS stimulating actions of Taltirelin hydrate such as antagonistic actions against pentobarbital-induced anesthesia and reserpine- induced hypothermia were found to be about 100 times stronger and about 8 times longer-lasting as compared with those of TRH. Meanwhile, the affinity of Taltirelin hydrate for TRH-receptors was about 10 times lower, and the endocrine action was about 5 times less potent than those of TRH. Therefore, high CNS-selectivity and long-lasting action of Taltirelin hydrate would be attributed to its high stability in the body and low affinity for TRH-receptors. Oral administrations of Taltirelin hydrate ameliorated consiousness impairment, memory impairment and motor dysfunction in several models. The clinical studies for patients with spinocerebellar degeneration are in progress.

Animals↗

PubMed1997

Heat production by brown adipocytes of FOK rats genetically resistant to a hot environment.

The FOK rat was established as an inbred strain with genotypic adaptation to a hot environment. To investigate the mechanism of the heat resistance of FOK rats, heat production by isolated brown adipocytes in FOK and WKAH rats was measured at 37.0 and 39.9 degrees C. Basal heat production by brown adipocytes of FOK rats was not significantly different from that of WKAH rats. Isoproterenol increased the heat production in a dose-dependent manner in both strains, while 10(-9) M isoproterenol caused a significant increase in WKAH rats and a negligible change in FOK rats. These results indicate that the reason why FOK rats are resistant to the severe heat is partly due to the low heat production by brown adipocytes.

Adaptation, Physiological↗

PubMed1997

Comparative analysis of CD45RA- and CD45RO-positive CD4+T cells in peripheral blood, synovial fluid, and synovial tissue in patients with rheumatoid arthritis and osteoarthritis.

To determine whether the predominant infiltration with memory CD4+T cells in joints is specific to the local immune and inflammatory response in rheumatoid arthritis (RA), the proportions of CD45RA+ or CD45RO+ cells in the CD4+T cell populations in three different compartments (i.e., peripheral blood, synovial fluid, and synovial tissue) from patients with RA and osteoarthritis (OA) were compared by two-color flow-cytometric analysis. In the CD4+T cell population of peripheral blood, the number of CD45RO+ cells was relatively higher than CD45RA+ cells in both RA and OA patients, but their percentages did not differ from those found in healthy individuals. However, the great majority of CD4+T cells present in synovial fluid and synovial tissue were CD45RO-positive and CD45RA-negative in both patient groups; although CD4+T cells infiltrating both the disease compartments were markedly greater in RA joints, their mean percentages of CD45RO+ cells were not significantly different from those in OA joints. These data indicate that an accumulation of CD45RO+ memory CD4+T cells is a generalized phenomenon during local inflammatory responses in both RA and OA joints, and may be due mainly to the propensity of these cells to preferentially transmigrate into the inflamed joint via adhesion molecules as compared with CD45RA+ naive CD4+T cells.

Aged↗

PubMed1997

[Remission by leukocytapheresis for a patient with ulcerative colitis found refractory by conventional drug therapies].

A 40-year-old male was admitted to our hospital on August 30, 1994 to receive a new ulcerative colitis (UC) therapy, leukocytapheresis (LCAP). On the admission day, he had bloody stool 5 to 6 times/day, abdominal pain, slight fever, and hypoproteinemia. His UC type was moderately severe left-sided colitis with pseudopolyposis. Prior to admission to our hospital, his condition had not improved for about 9 months, despite drug therapies such as salicylazosulphapyridine, intravenous high dose prednisolone, protease inhibitor, intraarterial hydrocortisone sodium succinate, 4 series of pulse therapies with metylpredonisolone, enema of corticosteroid, azathioprine (Imuran), and cyclosporine at another hospital. Thus he was introduced to our college hospital and treated by LCAP since September 1. After 10 LCAP sessions, remission was observed and the patient discharged on December 23. Until he was later operated on for heavy bleeding after he had discontinued treatment and had drunk heavily, he had maintained remission for 13 months with LCAP only once a month even after we gradually decreased the other medical supports and stopped all of them. After LCAP, the normalization of high percentage of leukocytes presented HLADR+ and lymphocytes presented CD 11 a+ CD 8+ was also observed. This suggests LCAP intercepts the excess immune reaction in UC by removing leukocytes.

Adult↗

PubMed1997

Frequent hepatic involvement in adult T cell leukemia: comparison with non-Hodgkin's lymphoma.

We examined 111 patients with acute type- or lymphoma type-adult T-cell leukemia (ATL) and compared them with 106 patients with non-Hodgkin's lymphoma (NHL). In addition to skin involvement and hypercalcemia which are already known to be frequent in ATL, ATL patients showed an higher incidence of hepatic involvement. There was more frequent palpable hepatomegaly, higher total bilirubin, GOT, GPT, lactate dehydrogenase (LDH), and alkaline phosphatase values in ATL than in NHL patients (p < 0.0001). Among 36 autopsied liver samples, invasion of ATL cells was confirmed in 22 cases. ATL patients with impaired hepatic function showed shorter survival times than patients without hepatic dysfunction. Moreover, ATL patients showed a worse performance status (PS), a higher incidence of lytic bone lesions, lower total protein (TP) and serum albumin levels than NHL patients. This invasive characters of ATL cells and consequent impaired general condition seemed to be factors affecting the poor prognosis recorded in ATL.

Adult↗

PubMed1997

[Leukocytapheresis for ulcerative colitis].

Major inclusion criteria for leukocytapheresis (LCAP) therapy were mainly insufficient response to conventional drugs therapy. LCAP was administered once a week for 5 weeks of intensive therapy and once approximately a month for maintenance therapy, for 38 patients with UC. LCAP could remove approximately 1 x 10(10) white blood cells in each session. In the evaluation, we classified the response to the LCAP as: 1) excellent, 2) moderately improved, 3) no change, and 4) deterioration. Clinical improvement was recognized in 29 of 38 patients (76%) including 8 with dramatic response during the intensive therapy, and continued throughout the maintenance therapy in 26 patients (68.4%). Even though their symptoms were mild, the patients with more than 5 years UC history seemed to be not effective. The patients with moderately improvement and with excellent response have kept remission for about 20 months and about 2.5 years on an average, respectively. Clinical and blood examinations showed no side effects in any cases. It suggests that LCAP is able to be a UC treatment between drug therapies and an operation.

Adult↗

PubMed1997

Increased production of interleukin-10 and inflammatory cytokines in blood monocytes of hemodialysis patients.

Chronic hemodialysis (HD) patients have defects in cell-mediated immunity. To investigate the mechanisms underlying this immunodeficiency, we studied the production of cytokines in peripheral blood mononuclear cells (PBMC) from HD patients. PBMC from 22 HD patients and 20 healthy controls were cultured for 48 h in the presence or absence of phytohemagglutinin (PHA), lipopolysaccharide (LPS), or tuberculin purified protein derivative (PPD). Cytokine levels were measured by enzyme-linked immunosorbent assays. Only 64% of HD patients had a positive tuberculin skin test compared to 90% of normal Japanese controls. HD patients showed a diminished proliferative response to PHA. Compared to healthy controls, stimulated PBMC from HD patients produced similar amounts of T cell-derived cytokines (interleukin-2 (IL-2) and interferon-gamma (IFN-gamma)), but greater amounts of monocyte-derived inflammatory cytokines (IL-1 beta, tumor necrosis factor-alpha (TNF-alpha), and IL-8) and a regulatory cytokine (IL-10). IL-10 production was positively correlated with IL-1 beta and TNF-alpha in healthy controls, whereas no correlation was observed in HD patients. Abnormal cytokine production by monocytes may contribute to the immunodeficiency seen in HD patients.

Cells, Cultured↗

PubMed1996

Organization of the gene encoding transcriptional repressor deltaEF1 and cross-species conservation of its domains.

DeltaEF1 (delta-crystallin/E2-box factor 1) is a widely distributed repressor of transcription which binds at the E2-box sequence, CACCTG. It carries seven zinc fingers (Zf) in two clusters and a homeodomain in the middle as potential DNA-binding domains. We cloned the genomic gene encoding chicken deltaEF1 and analyzed its organization. The gene consisted of nine exons, the N-proximal Zf were encoded by exons 5 through 7, and the C-proximal Zf by exons 8 and 9. Exon 7 also coded for the large middle portion of the protein including the homeodomain. Promoter analysis and RNase-protection assay indicated that the gene is driven by a G+C-rich promoter without a TATA box, and the transcription start points (tsp) cluster around 20 bp from the start codon located in exon 1. cDNA and genomic sequences of the mouse delta EF1 were cloned and compared with the chicken sequence. The deduced amino acid (aa) sequence was highly conserved between the chicken and mouse deltaEF1, no only in DNA-binding motifs but also in other blocks (78% overall aa identity). More recently reported DNA-binding proteins, AREB6 (human) ZEB (human) and BZP (hamster), were attributed to homologues of deltaEF1, among which only AREB6 represented full-length sequence. It was also indicated that rodent deltaEF1 lacked exon 3.

Amino Acid Sequence↗

PubMed1996

Relation of oxidative stress and glutathione synthesis to CD95(Fas/APO-1)-mediated apoptosis of adult T cell leukemia cells.

An IL-2 dependent adult T cell leukemia cell line (SO4) has been established that is sensitive to CD95-mediated apoptosis as well as a subline (R-SO4) that is resistant. Incubating SO4 cells with anti-CD95 IgM mAb caused concentration-dependent cell death. On the contrary, R-SO4 cells did not die even at 1000 ng/ml of anti-CD95 IgM mAb. The levels of CD95 expression on R-SO4 cells were one-third of those on SO4 cells. However a blocking Ab, anti-CD95 IgG mAb, did not induce complete resistance of SO4 cells to anti-CD95 IgM mAb as R-SO4 cells. As CD95 and TNF receptor are similar, and TNF/TNF receptor binding induces oxygen radicals, the involvement of oxidant and antioxidant systems in CD95-mediated apoptosis has been examined. The addition of anti-CD95 IgM mAb resulted in formation of intracellular oxygen radical species in the SO4 cells as measured using 2',5',-dichlorofluorescein as substrate. The oxygen radical production induced DNA damage as determined by formation of 8-hydroxydeoxyguanosine. No increase in the formation of oxygen radicals was observed in R-SO4 cells. Concentrations of the intracellular antioxidant, glutathione, and the key enzyme for its synthesis, gamma-glutamylcysteine synthetase, were 150% increased in R-SO4 cells in comparison with that of SO4 cells. Moreover, glutathione ester decreased the formation of 8-hydroxydeoxyguanosine. These results suggested that apoptosis mediated by CD95 in ATL cells is related to the production of oxygen radical species and cellular antioxidant systems, especially, glutathione synthesis.

Apoptosis↗

PubMed1996

The defective secretion of a naturally occurring alpha-1-antichymotrypsin variant with a frameshift mutation.

A newly found variant alpha-1-antichymotrypsin (ACT), ACT Isehara-2, has a deletion of two bases (AA) at codon 391 near the carboxyl terminus. This frameshift mutation caused a change in the amino acid sequence and generated 10 extra amino acids (408 amino acids total) [Tsuda, M., Sei, Y., Matsumoto, M., Kamiguchi, H., Yamamoto, Y., Shinohara, Y., Igarashi, T. & Yamamura, M. (1992) Hum. Genet. 91. 467-468]. The serum ACT levels in three unrelated heterozygotes with this mutant ACT gene were 37% 49% and 54% that of the normal individuals. To examine the reduced serum levels, the normal ACT and the mutant ACT created by site-directed mutagenesis were transfected into COS-7 cells for comparison. The value for the retention rate (intracellular ACT/total ACT) was apparently higher in the cells expressing mutant ACT Isehara-2 than those bearing the normal gene. In the pulse-chase experiments, the secretion of the synthesized mutant ACT into the medium was not observed, whereas the normal ACT was mostly secreted as a 64-kDa form. The endoglycosidase H digestion and an electron microscopic analysis indicated that the retained mutant ACT was present in the endoplasmic reticulum. These results provide the biochemical basis for the decreased serum ACT level of individuals with ACT Isehara-2, and suggest the importance of the carboxyl-terminal region for its secretion.

Amino Acid Sequence↗

PubMed1996

Adhesive improvement of the mechanical properties of a dense HA-cemented Ti dental implant.

We have been using dense, pure hydroxyapatite (HA) dental implants for the last 15 years and results have shown that dense HA is a chemically stable material with acceptable mechanical properties. However, due to HA's physical characteristics, particularly its brittleness, there is the risk that the implant will fail if the subsequent bone binding comprises less than one half of the root portion. To ensure greater implant success, a new cementing method has been developed that uses methacrylates for the bonding of the dense HA outer shell to the titanium (Ti) inner cylinder in a two-piece HA-cemented Ti implant. Mechanical property tests were conducted to compare the HA-cemented Ti implant bonded with this new acrylic cement with existing commercially available HA-cemented Ti implants bonded with a triethyleneglycol dimethacrylate (TEGDMA)-bisphenol-A diglycidyl ether (BisGMA compound). The vertical and horizontal compressive strength of this improved implant was respectively 3.4 and 6.1 times greater than the commercial implants. This increased strength of new acrylic cement is due to its ability to compensate for shrinkage that affects adhesion during curing, thereby providing stronger bonding.

Adhesiveness↗

PubMed1996

A new type of major aminopeptidase in bovine brain.

A new type of major aminopeptidase was purified from bovine brain by ammonium sulfate fractionation and TMAE-fractogel (anion exchange), arginine-Sepharose 4B, Sephadex G-150, and Sephadex G-100 column chromatography. The purified enzyme showed a maximum activity at pH 7.2, and its molecular size was estimated to be 98,000 by gel filtration and 104,000 by SDS-PAGE with or without 2-mercaptoethanol. Further properties were activation by thiol reagents; inhibition by EDTA, puromycin, bestatin, amastatin, actinonin, leuhistin and probestin; and very low concentrations of Cu2+, Cd2+, Pb2+, Al3+, Fe3+, and Zn2+ inhibited activity. The enzyme hydrolyzed several amino acyl-7-amido-4-methylcoumalin derivatives (amino acid-MCA). The order of MCA-substrate specificity expressed as kcat/Km is Lys-MCA > Arg-MCA > Leu-MCA > Met-MCA > Phe-MCA > Tyr-MCA > Ala-MCA >> Gly-MCA, Pro-MCA, Ser-MCA, Asn-MCA. Immunoreactivity of the antibody against the purified aminopeptidase was observed in human brain and most rat tissues examined including brain, liver, kidney, lung, heart, and skeletal muscle at the same molecular size as in bovine brain aminopeptidase. Most of the Lys-, Leu-, Met-, and Phe-MCA degrading activity in crude bovine and human brain extracts was absorbed by the aminopeptidase IgG, suggesting that this aminopeptidase is a major enzyme, sharing at least Lys-, Leu-, Met-, and Phe-MCA degrading aminopeptidase activities in the brains.

Amino Acids↗