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Biomedical subjects

K Mitamura

Publications and source records attributed to K Mitamura.

At least 91 records · Page 5Linked to original sources
PubMed1995

Sensorineural hearing loss in patients with large vestibular aqueduct.

In examining 181 patients (327 ears) with sensorineural hearing loss of unknown etiology and 25 people (50 ears) with normal hearing by high-resolution computed tomography (CT), the image of the large vestibular aqueduct (VA) was defined as being a visible large aperture (> or = 4 mm), and small distance between vestibule and traceable part of the VA nearest to the vestibule (> or = 1 mm). The large VA was found in 13 patients (23 ears, 7.0%); it was relatively frequent following hypoplastic cochlea (33 ears, 10.1%) in all the inner ear anomalies detected. In patients with large VA, high-frequency hearing was affected more than low frequency, and history of sudden hearing loss was observed frequently (61% of ears with large VA), which was found to be triggered by characteristic episodes such as minor head trauma, etc. Those clinical features were observed more in those without cochlear anomaly than in those accompanying cochlear anomaly. Pathogenesis of sensorineural hearing loss and characteristic fluctuation of hearing in those patients are discussed.

Adult↗
PubMed1995

A controlled study to determine the optimal dose regimen of interferon-alpha 2b in chronic hepatitis C.

OBJECTIVES: The efficacy of three different dose treatments of interferon (IFN) was evaluated in patients with chronic hepatitis C (HCV). METHODS: Ninety-one patients with chronic hepatitis C were allocated to receive 3, 6, or 10 U of recombinant IFN-alpha 2b three times weekly for 24 wk. The number of patients was 26, 35, and 30 in the low, middle, and high dose groups, respectively. Treatment was discontinued, however, in four patients (one in the middle dose group and three in the high dose group) because of depression occurring 1-3 months after therapy began. A total of 87 patients, therefore, was analysed and was comprised of 26 patients in the low dose group, 34 in the middle dose group, and 27 in the high dose group. RESULTS: At the end of treatment, serum levels of ALT were normal in 50% (13/26) of patients in the low dose group, 70% (24/34) in the middle dose group, and 74% (20/27) in the high dose group. Patients with persistent normalization of ALT for 12 months of follow-up were defined as sustained responders. Twelve months after treatment cessation, the percentage of sustained responders was 23% (6/23) in the low dose group, 44% (15/34) in the middle dose group, and 41% (11/27) in the high dose group. Including the four patients who required discontinuation of IFN administration, the percentage of sustained responders was 43 and 37% in the middle and high dose groups, respectively. The clearance of HCV RNA was 40% in the middle dose group and 33% in the high dose group. This decrease in the clearance of HCV RNA was prominent in the high dose group. The percentage tended to be higher in the middle dose group, but the differences were not significant. CONCLUSIONS: The results suggest that a regimen of recombinant IFN-alpha 2b in a dose of 6 U three times weekly for 24 wk may be appropriate for the treatment of chronic HCV.

Alanine Transaminase↗
PubMed1994

Efficacy of inactivated vaccine in preventing antigenically drifted influenza type A and well-matched type B.

OBJECTIVE: To evaluate the efficacy of currently used inactivated influenza vaccine during a severe epidemic caused by antigenically drifted influenza type A(H3N2) and well-matched type B viruses during the 1992-1993 season. DESIGN: Prospective nonrandomized controlled trial. SETTING: An urban general hospital pediatric asthma clinic in Japan. PARTICIPANTS: A total of 137 children with moderate to severe asthma (mean age, 7.0 years; range, 2 to 14 years). INTERVENTION: Eighty-five children received trivalent split-antigen vaccine containing A/Beijing/352/89 (H3N2) and B/Bangkok/163/90 (B/Panama/45/90-like strain). Fifty-two were unvaccinated. MAIN OUTCOME MEASURES: Protection against infection was determined using hemagglutination inhibition test and virus isolation. Clinical efficacy was estimated based on febrile episodes with antibody rise or virus isolation. RESULTS: Although marked antigenic drift in hemagglutinin was demonstrated in the epidemic virus (A/Beijing/32/92-like strain), the protection against influenza type A(H3N2) infection was 67.5% (P < .01). The protection against influenza type B infection was 43.7% (P < .01), although the epidemic influenza type B viruses were antigenically almost identical to the vaccine strain. Inactivated vaccine was not effective for protection against influenza type B infection in children younger than 7 years. High clinical effectiveness was demonstrated in children at least 7 years of age during the epidemic. CONCLUSIONS: Our data suggest that current inactivated vaccine is highly effective for protection against influenza type A(H3N2) virus infection regardless of antigenic drift. In contrast, the protective efficacy obtained by vaccination may not be sufficient against influenza type B virus infection, and especially in young children, it does not offer protection.

Adolescent↗
PubMed1994

Derivatization of thiol-containing compounds.

The determination of thiol-containing compounds in biological fluids is important in biochemistry and clinical chemistry. In this paper, derivatization reagents for thiols are reviewed with respect to their reactivity, selectivity, spectroscopic characteristics and their applicability especially to high-performance liquid chromatography. Derivatization used in ultraviolet and electrochemical detection. The derivatization reagents contain a functional group, e.g. an N-substituted maleimide, active halogen or aziridine, which react with the thiol group. Derivatization for use in flow injection analysis, thin-layer chromatography or gas chromatography-mass spectrometry is also described.

Chromatography, High Pressure Liquid↗
PubMed1994

In vivo antiviral effects of mismatched double-stranded RNA on duck hepatitis B virus.

The antiviral activity and ability of mismatched double-stranded RNA (m-dsRNA), r(I)n.r(C12-U)n, to induce interferon (IFN) were evaluated in ducks chronically infected with duck hepatitis B virus (DHBV). When m-dsRNA was administered intravenously at a single dose of 5 mg/kg, serum DHBV DNA concentrations decreased significantly for 3 days (P < 0.002). However, the DHBV DNA concentrations returned to the pretreatment levels 4 days after treatment. Inhibition of DHBV DNA replication in the liver was also observed 2 days after treatment. Serum IFN activity peaked 3 hours after administration of m-dsRNA, then rapidly declined. 2'-5' Oligo-adenylate synthetase (2'-5'AS) activity increased gradually after treatment and remained elevated for at least 48 hours. In ducks receiving m-dsRNA once daily for 7 consecutive days, serum DHBV DNA concentrations on the last day of treatment were decreased by 76 +/- 12% (P < 0.05) in ducks that received 0.2 mg of m-dsRNA per kg and by 65 +/- 12% (P < 0.05) in ducks that received 1 mg of m-dsRNA per kg. This decrease persisted for at least 2 weeks after the cessation of treatment in all ducks. These results suggest that m-dsRNA effectively inhibits DHBV replication in vivo, and that IFN induction and stimulation of 2'-5'AS activity contribute to the inhibition of DHBV replication by m-dsRNA.

Animals↗
PubMed1994

Soluble CD4/CD8 molecules in rheumatic disorders.

The CD4 and CD8 glycoproteins which predominantly exist on T-helper and T-suppressor/cytotoxic cells are the physiological ligands for major histocompatibility complex class I or class II molecules on target cells such as B cells and antigen-presenting cells. These CD4 and CD8 molecules occur not only bound to membranes but also in soluble form in the serum. They may deliver regulatory signals to immunocompetent cells in vivo. The recent development of a solid-phase immunosorbent assay for soluble CD4 and CD8 molecules has enabled us to gain insight into the etiopathogenesis of autoimmune diseases on the basis of T-cell functional disability. This paper discusses the pathogenesis of autoimmune rheumatic diseases based on the findings for these molecules.

CD4 Antigens↗
PubMed1994

Retention behavior of conjugated metabolites of vitamin D and related compounds in high-performance liquid chromatography.

The retention behavior of sulfates or glucuronides of provitamin D, vitamin D, and 25-hydroxyvitamin D3, together with its fluorescent derivatives, are examined with reversed-phase high-performance liquid chromatography. Inclusion chromatography using cyclodextrin as a mobile-phase additive is also used for this purpose. Conventional reversed-phase high-performance liquid chromatography clearly separates the positionally isomeric conjugates of 25-hydroxyvitamin D3. The addition of the host compound to the mobile phase is effective in separating the pairs of fluorescent derivatives of vitamin-D3 and -D2 conjugates or provitamin-D3 and -D2 conjugates.

Calcifediol↗
PubMed1994

DNA alterations in cells from hereditary non-polyposis colorectal cancer patients.

To determine if the MCC, DCC or p53 gene is associated with susceptibility to hereditary non-polyposis colorectal cancer (HNPCC), these genes in normal cells from 12 HNPCC patients were analysed by polymerase chain reaction-single strand conformation polymorphism analysis. No changes which may alter the amino acid sequences of these genes were detected, suggesting that these genes are not associated with the susceptibility to HNPCC. Only one of nine HNPCC cancers showed mutations in the MCC and p53 genes on the same analysis. Loss of heterozygosity in chromosomes 5q, 17p, 18q and 22 was detected in four of the nine cancers, all of them being positive as to metastasis to lymph nodes. Abnormalities of the (CA)n repeat were found in six cancers, including all four without metastasis. These data indicate that tumor suppressor genes in chromosomes 5q, 17p, 18q and 22 are associated with the late stage of colorectal tumorigenesis in HNPCC, whereas the (CA)n repeat abnormalities are an early event of tumorigenesis and more essential to HNPCC.

Adult↗
PubMed1994

[Evaluation of combination chemotherapy for advanced gastric carcinoma as a neoadjuvant chemotherapy with CDDP, MMC, etoposide and 5'-DFUR].

Seven cases of nonresectable gastric carcinoma with lymph node metastasis were treated with combination chemotherapy [CDDP 75 mg/m2 i.v. day 1 (A method: Ccr > or = 50 ml/min) or 20 mg/m2 i.v. day 1, 2, 4, 5 (B method: Ccr < 50 ml/min), MMC 10 mg/m2 i.v. day 1, etoposide 50 mg/body i.v. day 3, 4, 5, 5'-DFUR 2,100 mg/body po 4 day/week] every 4 weeks as a neoadjuvant chemotherapy. After treatment, the size of the primary tumor was reduced in four of seven cases. The lymph nodes disappeared in one case and were reduced in size in four cases. Metastatic liver tumors were found in four cases. They disappeared in one case and the size was reduced in one of seven cases. One patient with renal dysfunction was treated with B method. However, renal dysfunction did not become worse. Five patients were operated after chemotherapy. Absolute curative resection was performed in three of them. The total rate of curative resection was 43% (3/7). Four patients were alive for 19 months after operation. The main side effects of this therapy were nausea, anorexia and bone marrow suppression, which, were found in all patients. These results suggest that this combination chemotherapy is as effective as neoadjuvant chemotherapy for advanced gastric carcinoma.

Aged↗
PubMed1993

Increased soluble IL-2 receptor in serum of patients with systemic lupus erythematosus.

We estimated the concentration of soluble IL-2R (sIL-2R) in the serum of patients with systemic lupus erythematosus (SLE) and examined the relationship between the serum levels of sIL-2R and clinical features or laboratory data. We found that elevated levels of sIL-2R were present in the serum of SLE patients with discoid rash, and sIL-2R concentrations were correlated with the soluble CD4 and soluble CD8 concentrations but not with classical serological marker, anti-DNA antibody or complement titer.

Adolescent↗
PubMed1993

High prevalence of hepatitis B and C viral markers in Japanese patients with hepatocellular carcinoma.

In order to assess the etiologic role of hepatitis C virus (HCV) as well as hepatitis B virus (HBV) in the etiology of HCC, we compared the prevalence of HCV-related antibodies (anti-C100-3, anti-CP9, anti-CP10) and HBV-related markers (HBsAg, anti-HBs, anti-HBc) in sera of patients with liver cirrhosis (LC) with (n = 62) and without (n = 54) hepatocellular carcinoma (HCC). In HBsAg-negative cases, at least one HCV-related marker (including HCV RNA) was detected in 92.3% (48/52) of HCC cases and in all of the 44 LC cases without HCC, with no significant difference between these two groups. In HBsAg-positive cases, the prevalence of either one of these HCV-related markers was 40.0% (4/10) both in patients with and without HCC, and there was no significant difference between these two groups. Moreover, in HBsAg-negative cases and 11 cases of positive HCV-related markers, the prevalence of anti-HBs and/or anti-HBc was significantly higher in LC patients with HCC (85.4%) than those without HCC (43.2%, P < 0.001). These results show a high prevalence of hepatitis B and C viral markers in Japanese patients with HCC and further indicate that previous HBV infection is a risk factor in the occurrence of HCC in HBsAg-negative LC and LC with positive HCV-related markers.

Carcinoma, Hepatocellular↗