The Y-family of DNA polymerases.
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Animals↗
Biomedical subjects
H Ohmori
Publications and source records attributed to H Ohmori.
Expression of human and mouse genes encoding polkappa: testis-specific developmental regulation and AhR-dependent inducible transcription.
BACKGROUND: Human polkappa is a newly identified low-fidelity DNA polymerase. While the enzyme bypasses an abasic site and acetylaminofluorene-adduct in an error-prone manner, it bypasses benzo[a]pyrene-N2-dG lesions in a mostly error-free manner by incorporating predominantly dC opposite the bulky lesions. Benzo[a]pyrene (B[a]P) is activated through intracellular process mediated by the arylhydrocarbon receptor (AhR, also called the dioxin receptor), which is a ligand-activated transcription factor with high affinities for aromatic compounds such as B[a]P and dioxin. RESULTS: We examined promoter structures of the human POLK and mouse Polk genes to study how their expressions are regulated. The mouse Polk gene is developmentally regulated in testis and utilizes two transcription start sites during spermatogenesis, while it utilizes only one site in tissues other than testis. Both of the mouse Polk and the human POLK genes have two AhR-binding sites in the promoter regions and the expression of the mouse Polk gene is indeed enhanced upon AhR-activation. CONCLUSIONS: The AhR activation increases expression of the mouse Polk gene and probably the human POLK gene, the product of which bypasses benzo[a]pyrene-N2-dG lesions in a mostly accurate manner. Thus, polkappa seems to function to reduce mutagenesis at benzo[a]pyrene-adducts, although it may also have a role related to spermatogenesis.
Animals↗
Restoration of immunocyte functions by thymosin alpha1 in cyclophosphamide-induced immunodeficient mice.
Thymosin alpha1 (Talpha1) is an oligopeptide hormone originally isolated from the thymus gland, and has been reported to have stimulating effects on the differentiation of T cells and NK cells. These immunostimulating properties have been considered to be useful for improving immune disorders associated with various diseases including cancer, AIDS and hepatitis. Here, we characterized immunostimulating properties of Talpha1 in experimental immunodeficiency of mice that was induced by the administration of cyclophosphamide (CY). Repeated injection of 30-300 microg/kg/day of Talpha1 after CY-treatment significantly accelerated the restoration of the reduced number of CD4+CD8+ T cells in the thymus. Talpha1 administration was effective in restoring the suppressed activities of helper T cells and cytotoxic T cells in CY-treated mice. Talpha1 also had stimulating effects on reduced activity of lymphokine-activated killer cells in CY-treated mice. These results indicate that Talpha1 is stimulatory for both humoral and cellular immune responses, thus providing the immunological basis for the clinical benefit of this compound.
Animals↗
Effects of exercise training on home blood pressure values in older adults: a randomized controlled trial.
OBJECTIVE: To determine the effects of exercise training on the blood pressure (BP) values of older adults, using home blood pressure measurement. DESIGN: Randomized controlled trial. PARTICIPANTS: A total of thirty-nine free-living older adults (including 19 men) aged from 60-81 years with home systolic blood pressure > 120 mmHg and without significant cardiopulmonary-musculoskeletal disease, were randomly allocated to either 25 weeks of exercise training (exercise group) or to a control program (control group). MAIN OUTCOME MEASUREMENTS: Change in the 2-week averages of home systolic and diastolic blood pressure values measured with a validated automatic device before, during and after the intervention period. RESULTS: Compared with the control group, the exercise group showed a significant decrease in values for home systolic blood pressure (maximum between-group difference = 7.7 mmHg, P = 0.003) and home diastolic blood pressure (4.2 mmHg, P = 0.001). These changes were observed for both genders. CONCLUSIONS: Exercise training was effective for older adults in lowering home blood pressure values. This is the first trial to demonstrate the usefulness of home blood pressure measurement in examining the effect of exercise training on blood pressure values.
Aged↗
Neurally mediated syncope and cardiac beta-adrenergic receptor function.
To evaluate the mechanism of neurally mediated syncope (NMS), we investigated basal autonomic nerve function using a conventional pharmacological method and [123I]-metaiodobenzyl-guanidine (MIBG) single photon emission computed tomography (SPECT). Nine patients with NMS, whose syncope was induced by head-up tilt test with or without isoproterenol, underwent [123I]-MIBG SPECT. Eight of nine NMS patients showed reduced myocardial uptake (two patients, diffuse; four patients, anteroseptal and inferior; one patient, anteroseptal; one patient, inferior). In the study of pharmacological autonomic nervous function test, atropine sulfate (atr.) (0.04 mg/kg), isoproterenol (isp.) (5 x 10(-3) microg/kg/min), propranolol (prop.) (0.2 mg/kg), phenylephrine (phenyl.) (0.4 microg/kg/min), and phentolamine (phent.) (0.2 mg/kg) were successively administered to patients with NMS (n = 5) and control subjects (n = 5). The heart rate (HR) after atr. and prop., and systolic blood pressure (SBP) after phent. were defined as intrinsic HR (IHR) and intrinsic SBP (ISBP). Parasympathetic activity (increase in HR by atr.), beta-sympathetic tone (HR after atr. minus IHR), beta-sensitivity (change in HR by 1 microg isp./kg/min), beta-secretion (beta-tone/beta-sensitivity), alpha-sympathetic tone (SBP before phenyl. minus ISBP), alpha-sensitivity (change in SBP by 1 microg phenyl./kg/min) and alpha-secretion (alpha-tone/alpha-sensitivity) were also calculated. The beta-secretion was decreased (0.0027+/-0.0008 versus 0.0060+/-0.0004 microg/kg/min/isp.; p < 0.05), while the beta-sensitivity was increased (5850+/-947 versus 3150+/-292 beats/microg/kg/min isp.; p < 0.05) in NMS compared with control subjects. In the other indexes, there were no significant differences between two groups. The results of the present study suggest that increased beta-sensitivity may contribute hypercontraction of left ventricles, which might partially explain the mechanism of NMS.
3-Iodobenzylguanidine↗
Anodization in oligo(ethylene glycol) as an initial derivatization tool for preparing glassy carbon electrodes covalently modified with amino compounds: effective access to a 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-modified glassy carbon electrode.
Anodization in HO(CH2CH2O)nH (1a, n=2; 1b, n=3; 1c, n=4) as an initial derivatization tool for preparing glassy carbon (GC) electrodes covalently modified with amino compounds was explored. As an amino compound to be immobilized, 4-amino-2,2,6,6-tetramethylpiperidinyl-1-oxyl (4-amino-TEMPO) was selected. When GC electrodes anodized at 2.0 V vs. Ag wire coated with AgCl in 1 containing RCH2CH2SO3Na (2a, R=H; 2b, R=OH) were treated with a N,N-dimethylformamide (DMF) or CH2Cl2 solution of 4-amino-TEMPO and 1,3-dicyclohexylcarbodiimide (DCC), TEMPO-modified GC electrodes were afforded. Coverage (gammaTEMPO) of the electrode surfaces by TEMPO was estimated by cyclic voltammetry in CH3CN containing NaClO4. A TEMPO-modified GC electrode with the best gammaTEMPO (1.36 x 10(-10) mol/cm2) was obtained by anodization in 1b containing 2a at the expense of 3.0 C followed by amidization in DMF for 7 d. On cyclic voltammetry, the TEMPO-modified GC electrode showed good and stable electrocatalytic ability for oxidation of allyl alcohol in the presence of 2,6-lutidine.
Carbon↗
Hydrogen peroxide-induced deacetylation of acetyl resorufin as a novel indicator reaction for fluorometric detection of glucose using only glucose oxidase.
Hydrogen peroxide (H2O2)-induced deacetylation of non-fluorescent acetyl resorufin (1) to fluorescent resorufin (2) as a novel indicator reaction for fluorometric detection of glucose using only glucose oxidase (GOD) is described. When a 1:1:1 mixture of 1 (in CH3CN), glucose, and GOD (each in pH 7.4 phosphate buffer) was incubated at 25 degrees C under aerobic conditions, the resulting solution turned yellow to fluorescent pink due to 2. The formation of 2 was markedly retarded on incubation under anaerobic conditions. When a mixture of 1 and H2O2 was incubated under aerobic conditions, the formation of 2 was noted as in the case of the enzymatic reaction of 1. These results demonstrated that the observed color change is brought about through deacetylation of 1 to 2 induced by H2O2 generated in GOD-catalyzed oxidation of glucose. With regard to the fluorometric traces of the enzymatic reaction with 1 (0.2 mM), GOD (0.5 mg/ml), and glucose at 25 degrees C, fluorescence intensity exhibited a linear relationship against glucose concentration between 0.2 and 2.0 mm, with a correlation coefficient of 0.997. Neither ascorbic acid, uric acid, nor bilirubin significantly interfered with the transformation of 1 to 2 through GOD-catalyzed oxidation of glucose.
Ascorbic Acid↗
Resazurin as an electron acceptor in glucose oxidase-catalyzed oxidation of glucose.
The behavior of resazurin (1) as an electron acceptor in glucose oxidase (GOD)-catalyzed oxidation of glucose under anaerobic conditions is described. When a mixture of 1, glucose, and GOD in phosphate buffer (pH 7.4, 0.1 M) was incubated at 25 degrees C, the resulting solution turned purple to fluorescent pink due to the deoxygenated product, resorufin (2). On incubation of 1 with GOD alone or with H2O2 under essentially the same conditions, no color change was seen, indicating that generation of 2 in the enzymatic reaction is brought about through reduction of 1 by the reduced form (GODred) of GOD, which was also supported by the voltammetric behavior of 1. However, it was found that the enzymatic transformation of 1 to 2 is of no practical use as an indicator reaction for glucose determination using only GOD due to a slow reaction of 1 with GODred. Based on a ping-pong type mechanism with a steady-state approximation, KM and kcat for 1 as an electron acceptor from GODred were estimated to be 15+/-1.3 microM and (5.0+/-0.5) x 10(-2) s(-1), respectively.
Electrons↗
Production of an immunosuppressive polysaccharide, AZ9, in the culture of Klebsiella oxytoca strain TNM3.
A soil bacterium, Klebsiella oxytoca TNM3, was found to produce a polysaccharide named AZ9 with immunosuppressive activities. The culture of K. oxytoca in a jar fermentor resulted in an extreme increase in the viscosity of the culture broth (>10,000 mPa.s) due to accumulation of the polysaccharide with a high molecular weight. The molecular weight of AZ9 was successfully controlled by supplementing ethylenediamine tetraacetic acid (EDTA) and Fe2+ ion to the culture. Under optimized culture conditions, 39 g/l AZ9 with an average molecular weight of 200 kDa was produced, which was effective in suppressing IgE antibody production in mice.
Journal Article↗
Hair cell physiology and the feature extraction in the cochlear nucleus.
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Action Potentials↗
[Phase I study of amrubicin hydrochroride (SM-5887) for superficial bladder cancer in intravesical chemotherapy].
A phase I study of intravesical chemotherapy with amrubicin hydrochloride for superficial bladder cancer was conducted. Amrubicin was dissolved in 30 ml of physiological saline and injected intravesically on 6 consecutive days. The drug solution was retained for 2 hours. The starting dose was 60 mg/day, and the dose was escalated to 150 mg/day in 30 mg/day increments. Fifteen patients were entered into this study, of whom 14 were eligible and assessable for toxicity, and 13 were assessable for efficacy. The incidence and severity of cystic irritabilities such as micturition pain, pollakisuria and hematuria were related to the doses of amrubicin. At 150 mg/day, one of three patients experienced grade 3 micturition pain and pollakisuria. The dose-limiting toxicities, therefore, were micturition pain and pollakisuria, and the maximal tolerated dose was estimated to be 150 mg/day, considering that none of the three patients could retain the drug solution for 2 hours. One complete response and four partial responses were obtained in 13 assessable patients, and the overall response rate was 38.5%. A breakdown according to the doses was as follows. One PR of 3 patients were achieved at 60 and 90 mg/day, respectively 2 PRs of 5 patients at 120 mg/day, and one CR of 2 patients at 150 mg/day.
Administration, Intravesical↗
[Early phase II study of amrubicin (SM-5887) for superficial bladder cancer: a dose-finding study for intravesical chemotherapy].
An early phase II study (dose-finding study) of amrubicin hydrochloride for superficial bladder cancer was conducted. Amrubicin was dissolved in 30 ml of physiological saline and injected intravesically for 6 consecutive days. The drug solution was retained for 2 hours. Patients were randomly assigned to four groups, which were administered amrubicin at doses of 30, 60, 90, and 120 mg/day, respectively. Of 65 patients registered in this study, 63 were eligible and assessable for toxicities, and 55 assessable for efficacy. The response rate at each dose level was 50.0% (7PRs/14 patients) at 30 mg/day, 53.3% (8 PRs/15) at 60 mg/day, 61.5% (2 CRs + 6 PRs/13) at 90 mg/day, and 69.2% (2 CRs + 7 PRs/13) at 120 mg/day, respectively. These data suggests that the efficacy was related to the doses of amrubicin. The major toxicities were cystic irritabilities, such as micturition pain, pollakisuria and hematuria. These toxicities were related to the doses of amrubicin. Their incidence and the severity were not high compared with those reported about other anthracyclines such as doxorubicin and epirubicin. The optimal dose of amrubicin was estimated to be 90 to 120 mg/day in the intravesical treatment for superficial bladder cancer once a day for 6 consecutive days.
Administration, Intravesical↗
[Mutagenesis by Escherichia coli DinB and its mammalian homolog Pol kappa].
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Animals↗
[Ataxia, Friedreich type].
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Friedreich Ataxia↗
A morphometric study on postnatal development of the external granular layer of mice cerebella, focusing on local difference.
The external granular layer (EGL) of the cerebellum thickens, thins and disappears in its developmental process. We examined the thickness of the EGL, both intralobule differences and interlobule differences, in the whole midline sections of mouse cerebella for the entire postnatal period up to disappearance. The thinnest site in each lobule was located at the outer apex throughout the observation period, the thickest site was the portion facing the inner apex during early period, and that facing the convexity where the EGL curved in the later period. The observed interlobular differences of the EGL thickness were statistically divided into three groups, referred to as the early developing group (EDG), the late developing group (LDG), and the mixed-type group (MTG). The EDG consisted of the whole anterior lobe and a site in lobule VI facing the fissura prima. These sites thickened earlier, and showed a similar thickness on each observation day. The LDG was composed of all sites in the posterior lobe, with the exception of two sites where lobules VIII and IX confronted each other as well as the site included in the EDG. The sites in the LDG thickened later. They demonstrated a similar thickness during thickening, but varied during thinning. The MTG, consisting of two sites where lobules VIII and IX facied each other, showed features similar to the EDG in the mitotic zone and the LDG in the premigratry zone. These data may serve as the basis for studies on regional differentiation of the cerebellum.
Aging↗
Fidelity and processivity of DNA synthesis by DNA polymerase kappa, the product of the human DINB1 gene.
Mammalian DNA polymerase kappa (pol kappa), a member of the UmuC/DinB nucleotidyl transferase superfamily, has been implicated in spontaneous mutagenesis. Here we show that human pol kappa copies undamaged DNA with average single-base substitution and deletion error rates of 7 x 10(-3) and 2 x 10(-3), respectively. These error rates are high when compared to those of most other DNA polymerases. pol kappa also has unusual error specificity, producing a high proportion of T.CMP mispairs and deleting and adding non-reiterated nucleotides at extraordinary rates. Unlike other members of the UmuC/DinB family, pol kappa can processively synthesize chains of 25 or more nucleotides. This moderate processivity may reflect a contribution of C-terminal residues, which include two zinc clusters. The very low fidelity and moderate processivity of pol kappa is novel in comparison to any previously studied DNA polymerase, and is consistent with a role in spontaneous mutagenesis.
Base Pair Mismatch↗
Error-prone bypass of certain DNA lesions by the human DNA polymerase kappa.
The Escherichia coli protein DinB is a newly identified error-prone DNA polymerase. Recently, a human homolog of DinB was identified and named DINB1. We report that the DINB1 gene encodes a DNA polymerase (designated polkappa), which incorporates mismatched bases on a nondamaged template with a high frequency. Moreover, polkappa bypasses an abasic site and N-2-acetylaminofluorene (AAF)-adduct in an error-prone manner but does not bypass a cis-syn or (6-4) thymine-thymine dimer or a cisplatin-adduct. Therefore, our results implicate an important role for polkappa in the mutagenic bypass of certain types of DNA lesions.
Bacterial Proteins↗
Pathogenesis of cleft palate in mouse embryos exposed to 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD).
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces cleft palate in mouse embryos. It has been believed that TCDD inhibits palatal fusion by suppression of disappearance of medial edge epithelial (MEE) cells on palatal shelves. However, we found that exencephalic mouse embryos were resistant to the cleft palate-inducing action of TCDD. In the present study, we examined cell kinetics in MEE and palatal mesenchyme in embryos exposed to TCDD with or without exencephaly for elucidation of pathogenesis of cleft palate by TCDD. Pregnant Jcl:ICR mice were given TCDD orally at 40 microg/kg at gestation day (GD) 12.5. Embryos were harvested between GD 13.5 and GD 14.5 and examined for cell kinetics by bromodeoxyuridine (BrdU) and TUNEL methods. Exencephaly was induced by intraperitoneal injection of CdCl(2) at 6 mg/kg at GD 7.5. BrdU-positive cells were decreased in TCDD-treated embryos in MEE and mesenchymal cells. TUNEL-positive cells were detected in MEE both in TCDD-treated and untreated control embryos, as well as in embryos with or without exencephaly. We also measured the gap between shelves between GD 14. 0 and GD 14.5. There were no differences at GD 14.0 between control and TCDD-exposed embryos, but at GD 14.25 and GD 14.5, TCDD-exposed embryos had wider gaps than controls. These findings indicate that cleft palate by TCDD results from poor development of palatal shelves. Teratogenesis Carcinog. Mutagen. 20:73-86, 2000.
Animals↗