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Biomedical subjects

S Murakami

Publications and source records attributed to S Murakami.

At least 91 records · Page 5Linked to original sources
PubMed2001

Heat shock protein (HSP) 47 and collagen are upregulated during neointimal formation in the balloon-injured rat carotid artery.

Heat shock protein (HSP) 47, a collagen-specific molecular chaperone, is thought to be essential for the proper processing and secretion of procollagen molecules. We investigated the time course and localization of HSP47 and collagen expression after balloon catheter angioplasty in the rat carotid artery, based on the premise that accumulation of extracellular matrix components is a main feature of intimal hyperplasia in humans and in laboratory animals. Low levels of HSP47 expression were evident in uninjured carotid arteries. Northern blot analysis revealed that HSP47 mRNA expression was markedly stimulated 1--3 days after the induced injury and a high level was maintained for 7 days, followed by a gradual decline for up to 21 days after the injury. These changes in HSP47 expression paralleled changes in alpha 1(I) collagen expression. Immunohistochemical staining revealed colocalization of HSP47 and collagen in smooth muscle cells (SMCs) of the media and intima. In situ hybridization analysis showed that activated SMCs, which proliferated and migrated into the intima, expressed high levels of HSP47. In cultured human aortic SMCs, similar upregulation of HSP47 and alpha1(I) collagen by TGF-beta was noted. These results show that SMCs activated after balloon injury express high levels of HSP47 and collagen during cell proliferation and migration, hence an overproduction of collagen and development of intimal thickening. Thus, HSP47 plays a role in the formation and progression of neointima after angioplasty.

Animals↗
PubMed2001

Effects of aggression and wing removal on brain serotonin levels in male crickets, Gryllus bimaculatus.

When pairs of adult male crickets (Gryllus bimaculatus) that had been housed individually for 7 days were placed together, they fought, and dominant-subordinate relationships were formed within 1min. Aggressive behavior by the dominant male was repeated during the period in which the two males were kept together. Immediately after 10min of aggressive interaction, brain serotonin (5-hydroxytryptamine, 5-HT) levels were unchanged in dominant males and significantly reduced in subordinate males. The emission of aggressive song by dominant males is known to be abolished by removal of the wings. All wings were thus removed from male crickets. After 7 days of isolation, pairs of wingless males were placed together. The wingless males fought and formed dominant-subordinate relationships within 1min. The wingless, dominant males displayed aggressive behavior. Brain 5-HT levels in the wingless males were reduced immediately after 10min of aggressive interaction, and no significant differences in brain 5-HT levels were detected between the dominant and subordinate males, unlike the case for intact males. These data indicate a difference in brain serotonergic activity between dominant and subordinate male crickets during aggressive interaction, and suggest that aggressive behavior by dominant male crickets rapidly reduce brain 5-HT levels in subordinate ones. Furthermore, the data suggest that aggressive song is responsible for the change in brain 5-HT levels.

Journal Article↗
PubMed2001

Clinicopathological features of myeloid/natural killer (NK) cell precursor acute leukemia.

Four patients (three males and one female) were diagnosed as myeloid/natural killer (NK) cell precursor acute leukemia in our department. Two patients showed the extramedullary involvement at initial presentation. Leukemic cells expressed CD7, CD33, CD45 and CD56 in all patients. Additionally, CD13, CD34, HLA-DR, cytoplasmic CD3 and myeloperoxidase were expressed in some patients. Trisomy 10 was found in two patients, which has not been reported in this disease. Therefore, myeloid/NK cell precursor acute leukemia might be rather heterogeneous especially in chromosomal abnormality though it seemed to constitute the distinct clinical entity among acute myeloid leukemia of M0 subtype.

Acute Disease↗
PubMed2001

Age-related changes in cholinergic and purinergic neurotransmission in human isolated bladder smooth muscles.

We evaluated the correlation among age, cholinergic and purinergic neurotransmissions in the electrical field stimulation-induced contractions in human isolated urinary bladder smooth muscles, using the muscle bath technique. Human bladder specimens were divided into three groups (G1, under 50years; G2, 51-70years; G3, over 70years old), and each muscle strip was suspended in a thermostatically controlled organ bath filled with oxygenated Krebs-Henseleit solution, connected to an isometric force displacement transducer, and an isometric tension development was recorded. The contractile responses induced by KCl, carbachol, adenosine triphosphate (ATP) and electrical field stimulation, and the effects of atropine and alpha, beta methylene ATP on electrical field stimulation-induced contractions were observed. The contractile response to KCl and concentration-response curves for carbachol and ATP, and frequency-response curves for electrical field stimulation were not significantly different among the three groups. The atropine sensitive and resistant parts of contraction induced by electrical field stimulation were decreased and increased with age, respectively. There are significant positive and negative correlations between age and the purinergic, and age and the cholinergic neurotransmissions in human isolated bladder smooth muscles, respectively. The age-related changes in neurotransmissions may contribute to the changes in bladder function in the elderly.

Adenosine Triphosphate↗
PubMed2001

Survival of memory T cells specific for Japanese cypress pollen allergen is maintained by cross-stimulation of putative pectate lyases from other plants.

In view of recent studies on the mechanisms of the survival of peripheral memory T cells, we tested the biologic role of pectate lyase, a pectin-degrading enzyme, as the cross-reactive antigen required for the recurring survival signals for human T cells specific for Cha o 1, a pollen allergen molecule of the Japanese cypress. We determined a 16-mer epitope peptide for the T-cell clone, and prepared synthetic oligopeptides of homologous regions in putative pectate lyase of other plants. Of these homologous peptides, ZePel (Zinnia elegans), ban 17 (banana), and Amb a 1.1 (short ragweed) induced strong proliferative responses of the Cha o 1-specific T-cell clone in vitro. In addition, suboptimal doses of peptide homologs derived from banana and short ragweed enhanced the survival potency of this T-cell clone without detectable proliferative responses to the peptides. When there was no antigen stimulation, the T-cell clone decreased in viable cell number and lost antigen-specific proliferation activity on day 6 during in vitro incubation. On the other hand, T-cell clones incubated with these survival-inducing peptides maintained proliferative activity to Cha o 1 even on day 9. Serum derived from the donor patient did not contain detectable levels of IgE specific to banana or short ragweed by CAP-RAST. These results show that human T cells specific for pollen allergen seem to use cross-reactive pectate lyase peptides to deliver survival signals even in the absence of pollen allergen, and memory T cells maintained in such a manner might be functioning at the onset of allergic pollinosis, although pollen allergens are seasonal.

Allergens↗
PubMed2001

Pathology of the desmoplastic ameloblastoma.

Desmoplastic ameloblastoma is a rare variant of ameloblastoma and only 54 cases have been previously reported in the English literature. We report ten cases of desmoplastic ameloblastoma of the jaw observed between 1972 and 1998 and discuss the pathogenesis of the tumor. Eight of the ten tumors were located in the anterior region of the jaw. Radiographically, six cases showed mixed radiolucent/radiopaque appearance with ill-defined margins and the other four cases lacked typical findings of ameloblastomas. The tumors were located mainly in the alveolar region and occupied the tooth-bearing area, without tooth resorption or impacted teeth. Histologically, the desmoplastic ameloblastomas were characterized by extensive stromal desmoplasia, and small tumor nests of odontogenic epithelium were scattered in the stroma. Oxytalan fibers stained by potassium monopersulfate-aldehyde fuchsin were demonstrated in the stroma of all desmoplastic ameloblastomas. From these findings, we presumed that the desmoplastic ameloblastomas might have developed in the periodontal membrane.

Adolescent↗
PubMed2001

Taurine inhibits development of atherosclerotic lesions in apolipoprotein E-deficient mice.

1. The effects of taurine on the development of atherosclerotic lesions were investigated in apolipoprotein (apo) E-deficient mice, an animal model with severe hypercholesterolaemia and extensive atherosclerosis. These mice were fed a normal laboratory chow containing 2% taurine for 12 weeks. 2. Serum total cholesterol was significantly elevated after 12 weeks treatment with taurine. This elevation was due to increases in very low-density lipoprotein- and low-density lipoprotein-cholesterol. 3. Despite such effects on serum lipoproteins, analysis using en face oil red O staining revealed that taurine reduced the area of arterial lipid accumulation by 28%, as measured quantitatively as an index of atherosclerosis. Histological examination also demonstrated a decrease in the size of aortic lesions in taurine-treated mice. 4. Serum levels of thiobarbituric acid reactive substances (TBARS) in apoE-deficient mice were higher than in normolipidaemic C57BL/6J mice. Serum TBARS levels were significantly decreased by 12 weeks treatment of apoE-deficient mice with taurine. 5. Thus, taurine prevents the formation of atherosclerotic lesions, independently of serum cholesterol levels, and the results suggest that the anti-oxidative effects of taurine are related to its anti-atherosclerotic actions.

Animals↗
PubMed2001

Endocrine therapy for recurrence after definitive radiotherapy in patients with prostate cancer.

BACKGROUND: Long-term results were analyzed to evaluate the role of endocrine therapy in the management of local and distant recurrence of prostate cancer following external radiation therapy. METHODS: Between 1976 and 1994, 92 patients with untreated prostate cancer underwent external beam radiation therapy alone. Endocrine therapy had been started when relapse was evident. RESULTS: Failure was seen in 35 of 92 patients: 10 local, 19 distant and six biochemical failures. Endocrine treatment was performed in 28 patients with nine local and 19 distant failures. The cancer-specific survival rate from the endocrine treatment was 54.5% at 5 years. Prostate-specific antigen level in 20 of 20 patients (100%) decreased to below the normal limit 3 months after the start of endocrine therapy. In univariate analysis, T classification was the most significant variable for cancer-specific survival from the initial treatment. CONCLUSIONS: A favorable outcome was achieved by endocrine therapy in patients who had relapsed after external beam radiation monotherapy. Even the recurrent tumor had a sensitivity to androgen. Patients with locally advanced disease (T2b and T3) had poorer prognosis than those with minimally extended disease (T1b and T2a).

Aged↗
PubMed2001

Progression of prostate cancer to neuroendocrine cell tumor.

BACKGROUND: The progression to endocrine therapy-resistant prostate cancer is partly due to clonal change to neuroendocrine cell tumor. To elucidate this pathologic process, the clinical courses of four cases of neuroendocrine cell tumor that were found at autopsy are reported. METHODS: Between 1995 and 1999, autopsies were performed for 20 cases of prostate cancer. Lesions predominantly composed of a neuroendocrine cell tumor (small cell carcinoma) were found in four men. The clinical courses of these cases were compared to 16 other non-neuroendocrine cell tumors (adenocarcinomas). RESULTS: The outstanding features of the neuroendocrine cell tumors were: (i) survival was brief after relapse, although the duration of control by employing endocrine therapy varied; (ii) the prostate-specific antigen level did not increase after relapse; and (iii) the sites of metastasis were similar to those of common adenocarcinomas. CONCLUSION: The progression to a neuroendocrine cell tumor indicated a poor prognosis and slight (if any) changes in the serum prostate-specific antigen level. This tumor might not appear to respond to any therapeutic attempt.

Aged↗
PubMed2001

Mutational analysis of the structure and functions of hepatitis C virus RNA-dependent RNA polymerase.

The hepatitis C virus (HCV) nonstructural protein 5B (NS5B) is an RNA-dependent RNA polymerase (RdRP), a central catalytic enzyme for HCV replication. To further understand the structure and functions of NS5B, we introduced a series of 27 clustered and 19 point substitution mutations within and outside the well-known motifs conserved among RdRP by alanine scanning and investigated effects of these mutants on enzymatic activity of NS5B. Surprisingly, most of the mutations (22 of 27 clustered mutants) do not affect RdRP activity at all, indicating that the side chains of the corresponding amino acid residues are dispensable for the catalytic activity. On the other hand, 4 mutants, cm20t, cm194t, cm2t, and cm3t, are defective in RdRP activity. By further analysis with point mutations within these regions, E18, Y191, C274, Y276, and H502 were determined to be critical for the RdRP activity. Y276 was also shown to be critical for RNA template/primer association, although 3 amino acid sequences were identified to be important for RNA template binding by RNA-filter binding assays. Finally, 4 discontinuous sequences of NS5B (aa139-145, aa149-155, aa 365-371, and aa 382-388) were found to be essential for binding to NS5A as determined by glutathione S-transferase (GST)-pull down assays using GST-NS5A and FLAG-NS5B expressed in cotransfected cells, and GST-pull down assay in vitro. In light of the crystal structure models of NS5B recently reported, our results indicate that the RdRP activity of NS5B requires the longer loop and the helix located at the distal of the thumb, which are unique among RdRPs as well as reverse transcriptases.

Amino Acid Sequence↗
PubMed2001

Neurinoma of the greater superficial petrosal nerve developed acute facial palsy: case report and review of the literature.

The authors report on a patient with a greater superficial petrosal nerve neurinoma. The patient developed severe acute facial palsy and the palsy improved soon after removal of the tumor. We review of the literature and describe its rarity and surgical treatment with regard to other facial nerve neurinomas originating from the main trunk of the facial nerve.

Case Reports↗
PubMed2001

Transmastoid decompression as a treatment of Bell palsy.

OBJECTIVE: We sought to assess the efficacy of transmastoid decompression after steroid treatment. STUDY DESIGN: One hundred one adults with Bell palsy having denervation exceeding 95% after steroid treatment were divided into 2 groups. In 58 patients decompression from the labyrinthine segment to the stylomastoid foramen was performed, and the remaining 43 patients were only followed up. Using the Yanagihara score and House Brackmann grading system, the recovery from the palsy was assessed. RESULTS: There was a statistically significant difference in the final facial score of the 2 groups. Within 60 days after the onset, the chance of better recovery from the palsy was higher in the patients with decompression. CONCLUSION: In the era of steroid treatment, we cannot discard the transmastoid decompression of the facial nerve in the treatment of severe Bell palsy with profound denervation, although further effort is needed to obtain definitive evidence to show the benefit of the operation.

Adolescent↗
PubMed2001

Isolation of a benzoate-utilizing Pseudomonas strain from soil and production of catechol from benzoate by transpositional mutants.

Pseudomonas sp. Ba-0511 was isolated from soil by enrichment cultivation on a medium containing 6 mg/ml of sodium benzoate. The bacterium could grow on a medium containing 20 mg/ml of sodium benzoate by a successive enrichment culture. One hundred and twelve transpositional mutants of the bacterium produced catechol from benzoate and accumulated it outside of the cells. Among the mutants, strain BA+63 produced a maximal amount of catechol (2.3 mg/ml) from 6 mg/ml of sodium benzoate after growing for 10.5 h. The conversion rate of benzoate to catechol was 50% on a molar basis. The catechol production by the resting cells increased in the presence of glycerol, and the maximal amount of catechol produced from 6 mg/ml of sodium benzoate reached 3.3 mg/ml at the conversion rate of 72% after 5 h of incubation. The resting cells converted m-methylbenzoic acid to 3- and 4-methylcatechol and m-chlorobenzoic acid to 3- and 4-chlorocatechol.

Benzoates↗
PubMed2001

Adenosine regulates the IL-1 beta-induced cellular functions of human gingival fibroblasts.

In this study we examined the influence of adenosine on the cellular functions of human gingival fibroblasts (HGF), such as the production of inflammatory cytokines and extracellular matrices (ECM), and the expression and function of adhesion molecules. Concerning the expression of adenosine receptors, RT-PCR analysis revealed that HGF expressed adenosine receptor A1, A2a and A2b, but not A3 mRNA. Ligation of adenosine receptors by adenosine or its related analogue, 2-chloroadenosine (2-CADO), N(6)-cyclopentyladenosine (CPA) or CGS21680 synergistically increased IL-1beta-induced IL-6 and IL-8 production. In terms of ECM expression, adenosine and the adenosine receptor agonists, 2-CADO and CPA, enhanced constitutive and IL-1beta-induced expression of hyaluronate synthase mRNA, but not the mRNA levels of other ECM, such as collagen type I, III and fibronectin. Moreover, the adherence of IL-1beta-stimulated HGF to activated lymphocytes was also inhibited by adenosine, which is in part explained by the fact that adenosine down-regulated the IL-1beta-induced expression of ICAM-1 on HGF. These results provide new evidence for the possible involvement of adenosine in the regulation of inflammatory responses in periodontal tissues.

2-Chloroadenosine↗
PubMed2001

Mouse model of Bell's palsy induced by reactivation of herpes simplex virus type 1.

In order to investigate the mechanism of Bell's palsy, we developed an animal model of facial nerve paralysis induced by the reactivation of herpes simplex virus type 1 (HSV-1). Eight weeks after recovery from facial nerve paralysis caused by inoculation with HSV-1, the mice were treated with auricular skin scratch at the site of the previous inoculation, or with intraperitoneal injection of anti-CD3 monoclonal antibody (mAb), or combination of both procedures. No mice developed facial nerve paralysis when they were treated with either auricular scratch or mAb injection alone. In contrast, 20% of mice developed facial nerve paralysis with the combined treatment. With one exception, no mouse treated with either auricular scratch or mAb injection showed HSV-I DNA in their facial nerve tissue, whereas 4 out of 6 mice receiving both treatments showed HSV-1 DNA on day 10 after treatment. Histopathological findings showed neuronal degeneration in the geniculate ganglion and demyelination of the facial motor nerve in paralyzed mice. These findings suggest that a combination of stimuli, local skin irritation, and general immunosuppression is essential for successfully inducing facial nerve paralysis in mice with latent HSV-1 infection.

Animals↗
PubMed2001

Monoclonal antibody that binds to the central loop of the Tn10-encoded metal tetracycline/H+ antiporter of Escherichia coli.

Mouse monoclonal antibodies were prepared using His-tagged Tn10-encoded metal-tetracycline/H+ antiporter [TetA(B)His] as an antigen. From them, those reacting equally with His-tagged and wild-type TetA(B) were selected and named TCL-1. Cysteine-scanning mutants were used to determine the TCL-1 binding site on the TetA(B) protein. First, 12 Cys mutants of TetA(B) in which one residue in a protruding loop region was replaced by cysteine were constructed. Western blot analysis revealed the binding of TCL-1 to all of these Cys-mutants except for R186C. Then, we constructed 13 cysteine-scanning mutants, F179C to T191C. Among them, eight mutants, F179C to T182C, N184C, and T189C to T191C, exhibited TCL-1 binding, whereas the other five, K183C, T185C, R186C, D187C, and N188C, exhibited no or lower TCL-1 binding. These results clearly indicate that the sequence recognized by TCL-1 is 183Lys-X-Thr-Arg-Asp-Asn188 in the central loop region of TetA(B). TCL-1 is the first reported antibody that binds to a region other than the C-terminus of TetA(B), and the recognized amino acid sequence was identified.

Amino Acid Sequence↗
PubMed2001

The relation between plasma homocysteine concentration and methylenetetrahydrofolate reductase gene polymorphism in pregnant women.

OBJECTIVE: Our purpose was to clarify the influence of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism on plasma homocysteine (Hcy) concentrations during early pregnancy. METHODS: Between 1996 and 1998, Hcy concentration and MTHFR gene polymorphism were studied in 840 pregnant women between 6 to 12 weeks' gestation. Hcy concentration was measured by amino acid autoanalyzer (DLC-300, Nihon Denshi), and MTHFR genotypes were determined by the PCR/RFLP methods. Pregnancy outcomes were compared in association with Hcy concentration and MTHFR genotypes. RESULTS: A total of 816 of the 840 women were enrolled into the study because MTHFR genotypes were not available in 24 women. Genotypes of C677T in the MTHFR gene were CC: CT: TT (%) = 280 (34.3): 400 (49.0): 136 (16.7). Plasma Hcy concentration was significantly (p < 0.0001) higher in women with TT genotype than other genotypes [CC: CT: TT = 5.67 (2.8-10.6): 5.80 (2.5-20.1): 6.91 (3.5-20.9) nmol/ml, median (range)]. Women with hyperhomocysteinemia had severe preeclampsia (2 of 35 vs 5 of 714, p < 0.01) and stillbirth (2 of 35 vs 10 of 714, p < 0.05) more frequently than normohomocysteinemia. CONCLUSIONS: Plasma Hcy concentration during early pregnancy was higher in women with homozygote for the T677 allele in the MTHFR gene than other genotypes.

Adult↗