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Biomedical subjects

M Miki

Publications and source records attributed to M Miki.

At least 73 records · Page 4Linked to original sources
PubMed1997

CD8 cytotoxic T-cell clone rapidly transfers autoimmune diabetes in very young NOD and MHC class I-compatible scid mice.

A CD8 T-cell clone (YNK1.3) generated from acutely diabetic NOD mouse islets, showed proliferation and cytotoxicity when challenged with NOD and BALB/c islet cells and NOD-derived insulinoma cells. When 1-2 x 10(7) YNK1.3 cells were administered to 7-10-day-old NOD mice, the cells transferred overt diabetes very rapidly in each of the 16 recipients within 4 days of cell transfer. However, of 14 recipients receiving YNK 1.3 cells above 14 days of age none became diabetic. Fluorescent dye-labelled YNK1.3 cells extensively accumulated in the islets by 36 h after transfer in 7-day-old NOD recipients, while no significant insulitis was seen in 21-day-old recipients. Over half of NOD-scid recipients (5/9) rapidly became diabetic within 5 days after transfer of 1-2 x 10(7) YNK1.3 cells at 7 days of age, whereas only one of 12 recipients over 14 days of age became diabetic. Furthermore, YNK1.3 cells also transferred diabetes to H-2Kd-matched very young BALB/c-scid and CB17-scid mice, but not to C57BL/6-scid mice. Thus, optimally activated islet-specific CD8 T-cell clones are able to rapidly transfer diabetes to NOD and MHC class I compatible scid mice when a large enough number is administered at 7 days of age. Administration of monoclonal antibodies against adhesion molecules involved in the trafficking of lymphocytes from the circulation into the inflammatory tissues, could not prevent the cellular infiltration of YNK1.3 cells into the islets in 7-day-old NOD recipients. The results indicate that islet cells in the mouse around 7 days of age are generally susceptible to cytotoxic CD8 T cells, suggesting, therefore, that CD8 T cells may play an important role in the initiation of autoimmune diabetes in NOD mice.

Adoptive Transfer↗
PubMed1997

Interhead distances in myosin attached to F-actin estimated by fluorescence energy transfer spectroscopy.

Fluorescence resonance energy transfer (FRET) spectroscopy has been used to determine distances between probes attached to the most reactive sulfhydryl (SH1) group on individual myosin "heads." We measured intramolecular and intermolecular interhead distances as well as the distance between one head of heavy meromyosin (HMM) mixed with subfragment-1 (S1) heads attached to F-actin under rigor conditions. The SH1 cysteine was specifically labeled with either a donor (5-((((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid) or an acceptor probe (5-iodoacetamidofluorescein). In free solution, the distance between these probes was too large to allow significant FRET, but in the rigor complex with F-actin, intermolecular interhead distances between S1 molecules, HMM molecules, or S1 and HMM were determined to be 6.0-6.3 nm. The radial coordinate of the labels relative to F-actin was 5.0-6.4 nm. However, the intramolecular interhead distance in HMMs in which the two heads were labeled with D and A probes was estimated to be larger. The binding affinity of the second head of HMM(D/A) to F-actin may be reduced because of heterogeneous modification of the SH1 groups, such that the probability of single-head binding is increased.

Actins↗
PubMed1997

Frequent detection of hepatitis A viral RNA in serum during the early convalescent phase of acute hepatitis A.

The diagnosis of type A hepatitis is performed mainly by immunoglobulin M (IgM) anti-hepatitis A antibody assay, but it has not been established whether there is a correlation between changes in viremia and the clinical course of type A hepatitis. We examined hepatitis A virus (HAV) RNA in the sera from type A and non-A, non-B, non-C acute hepatitis and analyzed the relation of HAV viremia with alanine aminotransferase (ALT) and IgM-HA levels. Two hundred sera from 38 patients with type A acute hepatitis and 20 patients with non-A, non-B, non-C acute hepatitis were examined for the presence of HAV RNA. HAV RNA was detected by nested reverse transcription-polymerase chain reaction (RT-PCR) with primers located at the 5' non-translated region of HAV. HAV RNA was detected in 35 of 38 (92%) type A hepatitis patients and in 60 of 156 (38%) serum samples. In contrast, it was detected in none of 44 serum specimens from 20 non-A, non-B, non-C acute hepatitis patients. In type A hepatitis, the mean ALT level in HAV RNA positive specimens was 1,481 +/- 2,042 (range, 20-10,370) IU/L and that in HAV RNA negative specimens 186 +/- 330 (range, 8-1,698). The positivity of HAV RNA was correlated with the level of transaminase at the time of sample collection. The mean duration from the onset of symptoms to disappearance of HAV RNA was 18 +/- 14 days. The mean titer of IgM-HA in HAV RNA positive cases was 5.0 +/- 1.4, in negative cases 5.7 +/- 1.1, with no statistical difference. Our results indicate that HAV RNA in serum is detectable in the majority of type A hepatitis cases in their early convalescent phase by nested RT-PCR.

Acute Disease↗
PubMed1997

Perirenal pseudolymphoma: a case report.

A right nephrectomy was performed on a 51 year-old female with a tumor surrounding the right kidney since the possibility of malignant lymphoma could not be excluded based on radiography or a needle biopsy. An immunohistological examination of the surgically-resected specimen confirmed a diagnosis of pseudolymphoma. A pseudolymphoma involving the urinary tract is rare, and this is only the second reported case of pseudolymphoma in the perirenal space.

Female↗
PubMed1997

In vitro activity of HSR-903, a new quinolone.

The in vitro activity of the new fluoroquinolone HSR-903 was compared with those of ciprofloxacin, lomefloxacin, sparfloxacin, and levofloxacin. HSR-903 inhibited 90% of methicillin-susceptible and -resistant Staphylococcus aureus (MRSA) clinical isolates at 0.78 and 1.56 microg/ml, respectively, and its activity against MRSA was 16-fold higher than those of sparfloxacin and levofloxacin and 64-fold higher than that of ciprofloxacin. The MICs at which 90% of the isolates are inhibited (MIC90s) of HSR-903 for Streptococcus pyogenes and penicillin G-susceptible and -resistant Streptococcus pneumoniae (PRSP) were 0.10, 0.05, and 0.05 microg/ml, respectively. Against PRSP, the activity of HSR-903 was 4-fold higher than that of sparfloxacin and 32- to 256-fold higher than those of the other quinolones. The MIC90 of HSR-903 for Enterococcus faecalis was 0.20 microg/ml, and HSR-903 was more active than the other quinolones against enterococci. The activity of HSR-903 against members of the family Enterobacteriaceae and Pseudomonas aeruginosa was roughly similar to that of ciprofloxacin and greater than those of the other quinolones. Against Haemophilus influenzae, Moraxella catarrhalis, and Helicobacter pylori, HSR-903 was the most potent of the quinolones tested. The activity of HSR-903 was not affected by the medium, the inoculum size, or the addition of serum, but decreased under acidic conditions, as did those of the other quinolones tested. HSR-903 exhibited rapid bactericidal action and had a good postantibiotic effect on S. aureus and P. aeruginosa. HSR-903 inhibited supercoiling by DNA gyrase from Escherichia coli, but it was much less active against human topoisomerase II.

Anti-Infective Agents↗
PubMed1997

[A case of vesical endometriosis associated with Wunderlich syndrome].

A case of vesical endometriosis associated with unilateral renal agenesis and uterus didelphys (Wunderlich syndrome) is reported. A 20-year-old unmarried woman visited the gynecologic department with dysmenorrhea. She was referred to us because a bladder mass was detected on abdominal ultrasonography. She had no episode of gross hematuria. Cystoscopy revealed a finger tip-sized cystic mass dark red to dark blue in color. Computerized tomography and magnetic resonance imaging demonstrated right renal agenesis and uterus didelphys. The mass was located at the ureterovesical pouch and protruded into the bladder. Partial cystectomy, right hysterectomy and right salpingo-oophorectomy were performed. Histopathological diagnosis was endometriosis. The patient was treated with 400 mg danazol for 6 months has had no recurrence and regular menstruation.

Adult↗
PubMed1996

Induction of tolerance in murine autoimmune diabetes by transient blockade of leukocyte function-associated antigen-1/intercellular adhesion molecule-1 pathway.

The present study demonstrated that a short-term administration of mAbs against leukocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) at critical periods resulted in complete protection of autoimmune diabetes in non-obese diabetic (NOD) mice. When these mAbs were administered for only 6 days at 2 wk of age, neither diabetes nor insulitis was observed at 30 wk of age. It appears that the tolerance against beta cell Ag(s) was induced by this transient blockade of the LFA-1/ICAM-1 pathway. Protective suppressor activity was not enough to prevent diabetes because co-transfer of splenocytes from female NOD mice, which had received these mAbs at 2 wk of age, resulted in only a short delay of the diabetic onset caused by adoptive transfer of splenocytes from acutely diabetic NOD mice. Transfer of these splenocytes to young NOD mice could not also abrogate the spontaneous diabetes and insulitis. Furthermore, cyclophosphamide treatment could not abrogate the protection. When splenocytes from the treated NOD mice were transferred to NOD-SCID mice, none of the recipient mice developed significant insulitis and subsequent overt diabetes, suggesting the absence or the inactivation of diabetogenic effector T cells. However, splenic T cells from the insulitis-free NOD mice that had received the mAb treatment preserved proliferative responses to both islet cells and 65-kDa glutamic acid decarboxylase (GAD65) in vitro. These results suggest that a unique peripheral tolerance was induced by the transient blockade of the LFA-1/ICAM-1 pathway in an early age of NOD mice.

Adoptive Transfer↗
PubMed1996

Maleimidobenzoyl actin: its biochemical properties and in vitro motility.

Muscle G-actin treated with the hetero-bifunctional cross-linking reagent m-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS), denoted as MBS-G-actin, is not induced to polymerize into F-actin by salt and myosin subfragment 1 [Bettache, N., Bertrand, R., and Kassab, R. (1989) Proc. Natl. Acad. Sci. USA 86, 6028-6032]. However, the addition of salt and phalloidin together allowed MBS-G-actin to polymerize and the resulting polymer (P-MBS-G-actin) could activate the Mg2+ -ATPase of S-1 [Miki, M. and Hozumi, T. (1991) Biochemistry 30, 5625-5630]. When F-actin was treated with MBS (MBS-F-actin), unlike MBS-G-actin, intercross-links between monomers in F-actin occurred. The MBS-F-actin could activate the Mg2+ -ATPase of heavy meromyosin (HMM): its maximum turnover rate, Vmax, was almost the same as that of native F-actin, but the affinity of HMM for MBS-F-actin in the presence of ATP, Km, was about 3 times higher. Electron microscopy showed that both P-MBS-G-actin and MBS-F-actin had the double stranded structures of F-actin and formed the arrowhead structures when combined with HMM. By in vitro motility assay, the sliding velocities of P-MBS-G-actin and MBS-F-actin were found to be slightly slower than that of native F-actin. But the critical concentration of KCl, over which the sliding movement was not observed, for MBS-modified actins was considerably higher than for native F-actin. When MBS-modified actins were regulated by tropomyosin-troponin complex, they were less sensitive to the Ca2+ concentration for HMM ATPase activation and sliding movement. These results showed that the modification of some of the lysine residues in the actin molecule leads to change in the biochemical properties of F-actin.

Actins↗
PubMed1996

Chronic solitary pulmonary nodule due to unsuspected pulmonary infarction from silent pulmonary embolism.

A case of pulmonary embolism showing a longstanding solitary pulmonary nodule is presented. An asymptomatic 57 year-old man with a solitary nodule in the right lower lobe was referred to our hospital. A pulmonary perfusion-ventilation scan following a sudden onset of dyspnoea established the diagnosis of recurrent pulmonary embolism. The nodule gradually disappeared after anticoagulant treatment, indicating that the nodule was pulmonary infarction from silent pulmonary embolism. Although the incidence of pulmonary infarction is low in Japan, this case suggests that pulmonary infarction from silent pulmonary embolism should be considered as one important cause of a solitary pulmonary nodule.

Chronic Disease↗
PubMed1996

Metabolism of tetramethrin isomers in rat. III. Stereochemistry of reduced metabolites.

1. Three main urinary metabolites, two isomers of 3-hydroxycyclohexane-1,2-dicarboximide (3-OH-HPI-1 and 2) and 1,2-tetrahydrodicarboxylic acid (TCDA) were purified from rat treated with (1RS, trans)-tetramethrin [3,4,5,6-tetrahydrophthalimidomethyl (1RS, trans)-chrysanthemate]. 2. To elucidate the mechanism of formation of these reduced metabolites, the stereochemistry of 3-OH-HPI-1, 3-OH-HPI-2 and TCDA was clarified by chemical reactions, spectroanalysis (nmr) and X-ray analysis. 3. The sole difference in configuration between 3-OH-HPI-1 and 3-OH-HPI-2 was found to be the orientation of the hydroxyl group to the cyclohexane ring, and both of these reduced metabolites showed cis-addition of two hydrogens. In contrast, reduction resulted in the trans form with TCDA. 4. These findings indicate the existence of two different reduction reaction mechanisms in the rat.

Animals↗
PubMed1996

[Image cytometric DNA analysis in bladder tumors].

UNLABELLED: We studied image cytometric DNA analysis of bladder tumors to evaluate malignant potentials of bladder tumors. METHODS: Thirty nine samples were obtained by TUR from 37 patients. Nuclear DNA content of all samples were measured by image cytometer and were determined ploidy pattern by DNA histogram. RESULTS: Of 39 TCC non-diploid pattern was recognized in 50% of grade 1 cases, 73% of grade 2 cases and 100% of grade 3 cases. DNA ploidy was strictly correlated with histological grading in TCC. DNA non-diploid pattern was present in 67% of papillary tumors, 87.5% of non-papillary tumors and 100% in CIS. In diploid pattern 2 of 7 cases with grade 1 and 2 of 4 cases with grade 2 recurred. In non-diploid pattern 1 of 4 cases with grade 1, 4 of 10 cases with grade 2 and 4 of 6 cases with grade 3 recurred. There was no significant correlation between diploid and non-diploid pattern in grade 1, 2, 3. CONCLUSION: Image cytometric DNA analysis may be useful in addition to the classic and prognostic parameters of stage and grade, especially in TCC. The differences between image analysis system and flow cytometric analysis for DNA measurement were discussed.

Adult↗
PubMed1996

Mercury content in the gallstones and bile of Thai people (Chiang Mai and Bangkok) and Japanese.

Mercury contents in the gallstones and bile of patients living in Thailand (Chiang Mai and Bangkok) and Japan were studied by neutron activation analysis. The correlation between contents in the gallstones and bile, and the amount of mercury in the diet and environment was investigated by comparing the contents in patients living in three different areas. The content in the bile of the Japanese patients was significantly greater than that of the Thai patients. The distribution of mercury contents in the pigment and rare stones of patients living in Bangkok indicated a bipolarity. However, the distribution of the contents in cholesterol, pigment, and rare stones of Japanese patients did not indicate a bipolarity. Bipolarity would indicate the amount of mercury in dietary foods, and the pollution level of mercury. The mercury contents in the gallstones and bile would reflect the amount of mercury in the diet and environment.

Bile↗
PubMed1996

Radionuclide venography and its functional analysis in superior vena cava syndrome.

UNLABELLED: In addition to imaging, radionuclide venography maybe used for the functional assessment of superior vena cava (SVC) syndrome by applying the indices of transit time (TT), time of half-peak count (TH) and peak count ratio (PC ratio). METHODS: Ten healthy subjects (Group N) and 107 patients with SVC syndrome (64 symptomatic and 43 asymptomatic) were studied. Images were visually assessed for collaterals or jugular venous reflux and values of the indices were calculated. RESULTS: The 107 patients were subclassified into three groups according to the images obtained. Collateral circulation was seen in 37 patients (Group C). In 20 patients, jugular venous reflux was observed (Group J). Fifty patients who showed neither collaterals nor reflux were included in Group P. In comparison to Group N [3.6 +/- 0.56 see (sem)], TT values were significantly higher (p < 0.05) for Group J (7.13 +/- 1.16 sec) and Group C (7.00 +/- 0.87 sec). Values of TH were significantly prolonged (p < 0.05) for Group J (23.6 +/- 4.8 sec) and Group C (18.8 +/- 2.2 sec) in comparison to Group N (9.2 +/- 1.5 sec). PC ratio values were higher in all patient groups in comparison to Group N (3.4 +/- 0.57). CONCLUSION: These indices are potentially useful in the initial diagnosis and post-therapeutic evaluation of SVC syndrome. In the absence of other causes, appearance of jugular venous reflux may be considered a sign of SVC syndrome.

Adult↗
PubMed1995

Administration of monoclonal antibodies against vascular cell adhesion molecule-1/very late antigen-4 abrogates predisposing autoimmune diabetes in NOD mice.

The interaction of vascular cell adhesion molecule-1 and very late antigen-4 (alpha 4 beta 1-integrin) has been recently known to be profoundly involved in the trafficking of lymphocytes from the circulation into the inflammatory tissues. To elucidate the role of these molecules in the development of autoimmune diabetes, the expression of these adhesion molecules on inflamed islets and the effects of administration of monoclonal antibodies to these molecules on insulitis and overt diabetes were evaluated in nonobese diabetic (NOD) mice. Immunohistochemical study revealed the overexpression of vascular cell adhesion molecule-1 on vascular endothelium near or within inflamed islets and alpha 4-integrin on islet-infiltrating mononuclear cells. Either anti-vascular cell adhesion molecule-1 or anti-alpha 4-integrin monoclonal antibody prevented the transfer of diabetes in irradiated NOD mice which received spleen cells from acutely diabetic NOD mice. When both monoclonal antibodies were administrated to NOD mice during 2-30 weeks of age, neither lymphocytic infiltration to islets nor overt diabetes was observed. Furthermore, administration of these antibodies even from 10 weeks of age could inhibit the development of insulitis and diabetes, whereas administration during 2-5 weeks of age could not. Splenocytes obtained from these treated mice showed no significant change of cytokine production and preserved the ability to transfer diabetes into NOD scid/scid mice. This suggests that treatment with antibodies against these adhesion molecules can inhibit insulitis and diabetes without affecting the Th1/Th2 balance or effector T cells. The blockade of vascular cell adhesion molecule-1/very late antigen-4 interaction would be suitable for therapeutical treatment of the predisposing and latent type I (insulin-dependent) diabetic subjects.

Animals↗
PubMed1995

Interaction of NADPH-adrenodoxin reductase with NADP+ as studied by pulse radiolysis.

The reduction of flavin in NADH--adrenodoxin reductase by the hydrated electron (eaq-) was investigated by pulse radiolysis. The eaq- reduced directly the flavin of the reductase to form a blue semiquinone of the enzyme. Subsequently, the semiquinone decayed by dismutation to form the oxidized and fully reduced forms of the enzyme with a second-order rate constant of 4.4 x 10(4) M-1 s-1. In the presence of equimolar NADP+, the decay of eaq- accompanied an absorption increase at 400 nm, the spectrum of which, formed transiently, is identical to that of NADP radical (NADP.). Subsequently, the transient species decayed concomitantly with the formation of the semiquinone. The rate constant in the formation of the semiquinone was independent of the concentration of the enzyme (6.1 x 10(4) s-1 at pH 7.5). From these results, it is concluded that eaq- reacts with NADP+ bound to the enzyme to form NADP. initially, and subsequently, an electron flows from the NADP. to the flavin by an intracomplex electron transfer. A similar result was obtained in the reaction of CO2- or N-methylnicotinamide radical with the NADP(+)-adrenodoxin reductase complex. These results suggest that the nicotinamide moiety of NADP+ bound to the enzyme is accessible to the solvent and masks the flavin completely.

Animals↗