Biomedical subjects

H Hirano

Publications and source records attributed to H Hirano.

At least 199 records · Page 11Linked to original sources

PubMed1996

Decreased very-low-density lipoprotein and low-density lipoprotein receptor messenger ribonucleic acid expression in placentas from preeclamptic pregnancies.

OBJECTIVE: Our purpose was to investigate the levels of very-low-density lipoprotein and low-density lipoprotein receptor messenger ribonucleic acid expression in placentas obtained from normal pregnant women at various gestational stages and from patients with preeclampsia. STUDY DESIGN: The relative level of expression of very-low-density lipoprotein and low-density lipoprotein receptor messenger ribonucleic acid in each sample was determined by Northern blot analysis as a ratio of the intensity to that of glyceraldehyde-3-phosphate dehydrogenase messenger ribonucleic acid. RESULTS: The expression of very-low-density lipoprotein receptor messenger ribonucleic acid increased significantly (p < 0.05) from both the first (n = 9) and second (n = 8) trimesters to the third (n = 11) trimester. Similarly, the expression of low-density lipoprotein receptor messenger ribonucleic acid increased significantly (p < 0.05) from the first to the third trimester. The expression of both very-low-density lipoprotein and low-density lipoprotein receptor messenger ribonucleic acids in third-trimester placentas from preeclamptic pregnancies (n = 13) was significantly lower than that in normal pregnancies in the third trimester. CONCLUSION: These results demonstrate the expression of very-low-density lipoprotein and low-density lipoprotein receptor messenger ribonucleic acids in the human placenta, both of which increase at late gestational stages, and the decreased expression in cases of preeclampsia. Abnormal fetomaternal lipid metabolism resulting from low expression of these receptors in the placenta may be involved in the pathogenesis of preeclampsia.

Adult↗

PubMed1996

Sclerosing encapsulating peritonitis in patients undergoing continuous ambulatory peritoneal dialysis: a report of the Japanese Sclerosing Encapsulating Peritonitis Study Group.

Patients undergoing continuous ambulatory peritoneal dialysis (CAPD) who developed sclerosing encapsulating peritonitis (SEP) were retrospectively studied in 130 centers in Japan. Among 6,923 patients undergoing CAPD between 1980 and 1994 only 62 (0.9%) given CAPD developed SEP. There were 38 men and 24 women, ranging in age from 20 to 87 years (average age, 48.3 years). These 62 patients developed SEP 10 to 138 months (average, 65.4 months) after starting CAPD. The average frequency of peritonitis before developing SEP was 3.3 times. Five of the 62 patients with SEP had no history of peritonitis, and 27 (43.5%) of them died of various causes in the study period. The major causes of death were almost invariably related to problems concerning bowel obstruction or complications of surgery, such as malnutrition or septicemia. It was concluded that SEP is one of the most serious complications of CAPD, and constant surveillance is necessary to detect SEP in patients during CAPD.

Adult↗

PubMed1996

Saturable transport of valproic acid in rat choroid plexus in vitro.

In order to obtain in vitro evidence for a specific transport system of valproic acid (VPA) at the blood-cerebrospinal fluid (CSF) interface, the uptake of VPA by isolated rat choroid plexus was investigated. The uptake clearance of [3H]VPA decreased with the increase of the unlabeled VPA concentration in the incubation medium. Kinetic analysis yielded an apparent Km of 10.0 mM, Vmax of 0.0871 mumol s-1 g-1 and Kns, a permeability coefficient of the nonsaturable component, of 6.85 microL s-1 g-1, indicating that both saturable and nonsaturable systems may contribute to VPA uptake by choroid plexus. Organic anions, penicillin G, p-aminohippurate, salicylate, and probenecid significantly inhibited VPA uptake by choroid plexus. We suggest that VPA translocation through choroidal membrane is partly operated by the organic anion transport system. A significant decrease of VPA uptake induced by 2,4-dinitrophenol, stilbenedisulfonate, and hypothermia (10 degrees C) indicates the involvement of an energy-dependent, carrier-mediated transport system. These results demonstrate that VPA is actively transported through the rat choroidal epithelium via a saturable system probably shared by organic anions.

4-Chloromercuribenzenesulfonate↗

PubMed1996

A case of pregnancy with adult T-cell leukemia.

The incidence of adult T-cell leukemia (ATL) arising in women of childbearing age is documented infrequently. This report is the second in the world's literature of a case of ATL that occurred during pregnancy. A 43-year-old woman developed ATL during pregnancy and died of widespread disease 4 weeks after cesarean delivery.

Adult↗

PubMed1996

Diagnostic strategies of periodontitis based on the molecular mechanisms of periodontal tissue destruction.

OBJECTIVE: Periodontitis is a disease showing differences in disease progression between patients and between sites within a patient. Routine clinical examinations today are not useful enough to distinguish susceptible patients and active lesions from resistant patients and chronic lesions. Diagnostic markers should be pathogenic and inflammatory factors participating in periodontal tissue destruction. These are both local and systemic factors. MATERIALS AND METHODS: First of all, pathogenic factors and proinflammatory cytokines or mediators in gingival crevicular fluid (GCF) were examined and the difference was found between active and inactive periodontitis lesions distinguished by attachment loss. Active lesions were detected by discriminant-function analysis of these examinations, although the sensitivity of differential diagnosis was low. Then, we established a novel needle biopsy for understanding the pathophysiological conditions elicited in active and chronic inflammatory processes of periodontal tissue destruction. A variety of cytokines and mediators were detected in biopsied specimens by reversed transcription polymerase chain reactions (RT-PCR). Cytokine profiles were varied in inflammed periodontal biopsies. As IFN gamma mRNA expression was enhanced in inflamed gingiva, antigen-presenting-cell (APC) functions of human gingival fibroblasts (HGF) were examined. RESULTS: Despite the phenotypical resemblance of IFN gamma-treated HGF to so-called APC, HLA-DR positive HGF could not induce proliferation but suppressed proliferation of alloreactive peripheral blood T cells (PBT). However, HLA-DR positive HGF stimulated the proliferative responses of PBT which had been primed with allo-APC. Regulatory immune responses by IFN gamma were different in T cell conditions. CONCLUSIONS: Various kinds of cytokines participated in periodontal inflammation, and every cytokine is multi-functional. Complex and compound inflammatory processes can be clarified by examining cytokine networks and the precise effects of each cytokine on each of the cell types comprising periodontal tissue. It is, therefore, necessary for establishing diagnostic strategies to integrate pathogenic and inflammatory factors in periodontal tissue destruction.

Antibodies, Bacterial↗

PubMed1996

ROM7/BEM4 encodes a novel protein that interacts with the Rho1p small GTP-binding protein in Saccharomyces cerevisiae.

The RHO1 gene encodes a homolog of the mammalian RhoA small GTP-binding protein in the yeast Saccharomyces cerevisiae. Rho1p is localized at the growth site and is required for bud formation. The RHO1(G22S, D125N) mutation is a temperature-sensitive and dominant negative mutation of RHO1, and a multicopy suppressor of RHO1(G22S, D125N), ROM7, was isolated. Nucleotide sequencing of ROM7 revealed that it is identical to the BEM4 gene (GenBank accession number L27816), although its physiological function has not yet been reported. Disruption of BEM4 resulted in the cold- and temperature-sensitive growth phenotypes, and cells of the deltabem4 mutant showed abnormal morphology, suggesting that BEM4 is involved in the budding process. The temperature-sensitive growth phenotype was suppressed by overexpression of RHO1, ROM2, which encodes a Rho1p-specific GDP/GTP exchange factor, or PKC1, which encodes a target of Rho1p. Moreover, glucan synthase activity, which is activated by Rho1p, was significantly reduced in the deltabem4 mutant. Two-hybrid and biochemical experiments revealed that Bem4p directly interacts with the nucleotide-free form of Rho1p and, to lesser extents, with the GDP- and GTP-bound forms of Rho1p, although Bem4p showed neither GDP/GTP exchange factor, GDP dissociation inhibitor, nor GTPase-activating protein activity toward Rho1p. These results indicate that Bem4p is a novel protein directly interacting with Rho1p and is involved in the RHO1-mediated signaling pathway.

Base Sequence↗

PubMed1996

Cloning, expression, and mapping of UBE2I, a novel gene encoding a human homologue of yeast ubiquitin-conjugating enzymes which are critical for regulating the cell cycle.

From a human fetal-brain cDNA library we isolated a novel gene sharing significant homology with two yeast genes, UBC9 and hus5, which encode ubiquitin-conjugating enzyme 9 (UBC9). In yeast this protein is critical for normal mitosis, and seems to be closely involved in progression of G2 to M phase of the cell cycle. The human UBC9 (h-UBC9) cDNA, (gene symbol UBE2I), contained an open reading frame of 474 nucleotides encoding 158 amino acids. Its predicted peptide showed respectively 56% and 66% identity (75% and 82% similarity) with the products of UBC9 and hus5. Northern-blot analysis revealed expression of three transcripts, 6.4 kb, 3.3 kb, and 1.35 kb, in all human tissues examined. This gene, UBE2I, was mapped to chromosome band 16p13.3 by FISH.

Amino Acid Sequence↗

PubMed1996

Comparison of surface antigens on eosinophils from patients with eosinophilia.

Recent studies have suggested that there may be heterogeneity among human eosinophils. To study this further, surface antigens on blood eosinophils from patients with eosinophilia (23 bronchial asthma, 6 eosinophilic pneumonia, 1 Kimura's disease and 1 adult T-cell leukemia) and from 8 control subjects were examined using a new direct method for fluorescence detection of eosinophils. HLA-DR+ and CD4+ eosinophil counts were higher in patients with bronchial asthma and adult T-cell leukemia (ATL) than in patients from other groups and in control subjects. CD11b+ eosinophil counts in Kimura's disease and ATL were smaller than those in the other groups. CD45RO+ eosinophil counts in bronchial asthma and eosinophilic pneumonia were significantly higher (p < 0.05) compared with Kimura's disease, ATL and control subjects. CD44+ eosinophil counts in eosinophilic pneumonia were significantly higher (p < 0.05) compared with the other groups and control subjects. These results suggest the existence of functional heterogeneity in the different eosinophilic diseases, with eosinophils in bronchial asthma and eosinophilic pneumonia being more highly activated in migration, activation and immunoregulation. On the other hand, eosinophils in Kimura's disease and ATL might be functionally down-regulated. This heterogeneity of eosinophils may reflect differences in the pathogenesis of various eosinophilic diseases.

Adolescent↗

PubMed1996

Extraforaminal stenosis in the lumbosacral spine. Efficacy of MR imaging in the coronal plane.

PURPOSE: To review experience with MR images of extraforaminal (EF) stenosis in the lumbosacral spine. MATERIAL: MR images from 9 patients with 10 EF stenoses were reviewed. The diagnosis was confirmed in 6 patients at surgery, and in 4 on the basis of findings of nerve root injection combined with nerve block. RESULTS AND CONCLUSION: All patients had congenital lumbosacral anomalies with various degrees of fixation between the last formed level and the pelvis. In all cases, affected roots were compressed between the transverse process of the last lumbar segment and the sacral ala. MR using coronal plane imaging demonstrated the root impingement directly in the far lateral zone in all patients. However, sagittal and axial images were unable to define the EF stenoses in all patients. The results of this study show that a transitional vertebra is a cause of EF stenosis and that MR images using coronal plane are useful in the assessment of EF stenosis.

Female↗

PubMed1996

Use of serial semithin frozen sections to evaluate the co-localization of estrogen receptors and progesterone receptors in cells of breast cancer tissues.

The extent of co-expression of estrogen receptors (ER) and progesterone receptors (PgR) in breast cancer cells was examined immunocytochemically. Eight surgical cases of infiltrating ductal carcinoma designated as ER-positive and PgR-positive (ER+/PgR+) by enzyme immunoassay (EIA) were used. They were fixed with 4% formaldehyde and cut into serial frozen semithin sections. Using sections stained with either anti-ER or anti-PgR antibody, we ascertained the co-localization of ER and PgR in a single cell and estimated the ratio of the number of cells co-expressing ER and PgR. Twenty-six to 95% of the cells were immunopositive for both ER and PgR, 2-25% of them, varying in cases, were positive for ER but not for PgR, and <3% of the cells were positive for PgR but not for ER. The remaining 5-60% cells were positive for neither ER nor PgR. A significant percentage of breast cancer cells in tissues designated as ER+/PgR+ by EIA showed the phenotype of ER-positive but PgR-negative. The co-expression ratio of ER and PgR in biochemically detected ER+/PgR+ breast cancer may reflect a particular clinical parameter, such as the heterogeneous responsiveness of ER+/PgR+ breast cancers to hormonal treatment. Immunostaining of serial semithin frozen sections for two or more different antigens is a useful method to assess the correlation of localization of antigens.

Animals↗

PubMed1996

Angiotensin II induces ovulation and oocyte maturation in rabbit ovaries via the AT2 receptor subtype.

The present study was undertaken to investigate the role of angiotensin II (Ang II) in ovulation and ovarian steroidogenesis and prostaglandin (PG) production via the Ang II receptors in rabbit ovaries. In in vitro perfused rabbit ovaries, PD123319, a selective nonpeptide antagonist for AT2 receptors, reduced the Ang II-induced ovulation in a dose-dependent manner, whereas CV-11974, a selective nonpeptide antagonist for AT1 receptor, did not affect the Ang II-induced ovulation. Ang II also significantly stimulated the meiotic maturation of ovulated ova and follicular oocytes in the absence of gonadotropin. The addition of PD123319 at 10 (-6) M to the perfusate significantly inhibited the Ang II-induced oocyte maturation. Ang II did not stimulate the production of progesterone by perfused rabbit ovaries but significantly stimulated the production of estradiol (E2) and PGs. When PD123319 at 10(-6) M was added to the perfusate 30 min before the onset of Ang II administration, the Ang II-stimulated production of E2 and PGs was significantly blocked. Saralasin, a peptide analog of Ang II, inhibited the specific binding of [125I] iodo-[Sar1, Ile8] Ang II to rabbit ovarian membranes in a concentration-dependent manner, yielding an inhibitory constant (IC50) value of 1.58 x 10(-9) M. PD123319 and CV-11974 also inhibited the binding of [125I]iodo-[Sar1, Ile8] Ang II; however, PD123319 and CV-11974 were 15 and 40 times less potent than saralasin, respectively. Autoradiographic study revealed that an intense localization of Ang II receptors in the rabbit ovaries was present in the granulosa cell layers and the stroma of the preovulatory follicles. AT2 receptors were predominantly located in granulosa cells, whereas AT1 receptors were more concentrated in the stroma and thecal cell layers. In summary, Ang II induced ovulation and oocyte maturation and stimulated the production of E2 and PG by perfused rabbit ovary in vitro via the AT2 receptor. Thus, locally produced Ang II may be part of a novel intraovarian paracrine or autocrine control mechanism during the ovulatory process.

1-Sarcosine-8-Isoleucine Angiotensin II↗

PubMed1996

Prediction of the rodent carcinogenicity of organic compounds from their chemical structures using the FALS method.

Fuzzy adaptive least-squares (FALS), a pattern recognition method recently developed in our laboratory for correlating structure with activity rating, was used to generate quantitative structure-activity relationship (QSAR) models on the carcinogenicity of organic compounds of several chemical classes. Using the predictive models obtained from the chemical class-based FALS QSAR approach, the rodent carcinogenicity or noncarcinogenicity of a group of organic chemicals currently being tested by the U.S. National Toxicology Program was estimated from their chemical structures.

Animals↗

PubMed1996

[MRI abnormalities of the brain in neurologic complications following treatment of cancer in children].

During a 3-year period, 6 of 50 children with systemic malignacies developed neurologic complications such as hemiparesis, convulsions and loss of consciousness. The children consisted of 1 boy and 5 girls, from 3 to 12 years old, 3 with acute lymphoblastic leukemia and 3 with malignant lymphoma. Four patients received induction treatment that included intravenous administration of L-asparaginase and/or intrathecal administration of methotrexate. One patient received induction treatment and consolidation treatment that included intravenous administration of L-asparaginase. One patient received induction and consolidation treatment, and the protocol for peripheral blood stem cell transplantation. Laboratory examinations revealed coagulation dysfunction in 3 patients treated with L-asparaginase and 1 patient with disseminated intravascular coagulation (DIC). Magnetic resonance imaging (MRI) was performed on a 1.5-T unit, using spin-echo or fast spin-echo sequences. T1-weighted, T2-weighted, and proton density-weighted images were obtained in the axial and/or coronal plane (section thickness, 4 mm; inter-section gap, 2 mm). MRI was initially performed within 36 hours after the onset in all patients, and follow-up MRIs were performed for 6 months. MRI showed lesions involving the cortex and subcortex in 4 patients with coagulation dysfunction. In 2 of these 4 patients, Gd-enhanced T1-weighted images showed contrast enhancement in the surface of the gyrus, suggesting focal vascular stasis. Serial MRI revealed nearly complete resolution of the lesions. Symptoms were relieved in every case. The lesions on MRI were presumed to be due to venous thrombosis related to the coagulation dysfunction caused by L-asparaginase or DIC. On the other hand, in 2 patients with onset after intrathecal administration of high-dose methotrexate and cytarabine, MRI revealed multiple lesions involving the centrum semiovale and periventricular white matter. No Gd-enhancement of the lesion was detected. This MRI finding was consistent with leukoencephalopathy. As time passed, the symptoms improved completely, and the lesions became better demarcated. MRI is useful for differentiating lesions related to coagulation dysfunction from leukoencephalopathy.

Adolescent↗

PubMed1996

[The prognostic factors in astrocytic tumors: analysis by the Kaplan-Meier method and the Weibull log-linear model].

As the prognosis of astrocytic tumors depends on various factors, identifying prognostic factors should be useful for developing strategies to cope with them. Between 1975 and 1994, more than 200 patients with astrocytic tumors were treated in Kagoshima University. Of these patients, 149 (grade I: 17, grade II: 42, grade III: 41, grade IV: 42, unproven: 7) have been followed up. Records of these patients were retrospectively reviewed for age at the time of initial symptoms, gender, histological grade (WHO), extent of tumor resection, radiation therapy, and administration of anticancer agents. We used the Kaplan-Meier method and the Weibull log-linear model to analyze the relation between survival time and these prognostic factors. Survival time was counted from onset of symptoms, and age of initial treatment was used as a covariant. The mean age of males at the initial diagnosis was 40.8 years (n = 77), and that of females was 39 years (n = 72). Using the Kaplan-Meier method, the mean survival time of the 149 patients was 101 months (males; 72.7 months, females; 134.5 months). Mean survival time of grade II was 144.3 months, that of grade III was 95.2 months, and grade IV (glioblastoma) was 15.9 months. Histological grades and mean ages of the groups showed a positive correlation. Among grades II, III and IV, the Kaplan-Meier survival curves were significantly different (p < 0.0001) according to the log-rank test. By the extent of surgical resection (subtotal or greater resection, partial resection, and less than partial resection), the mean survival time showed a significant difference (p < 0.05) on the log-rank test. However, we could not detect a significant difference in survival time between the group that received chemotherapy and the group which did not. The Weibull log-linear analysis indicated that gender, age, histological grade (WHO), extent of surgery, and dose of radiation therapy were prognostic factors. Covariants of grades II, III, and IV made survival time 0.314, 0.179, and 0.069 times as long as that of grade I. The survival time after "partial resection" became 1.415 times as long as the survival time after "less than partial resection". The covariant of "greater than subtotal resection" showed a prolonged survival time of 2.916 compared with that of "less than partial resection". As for age at treatment, the older the patient was, the shorter the survival time. The rate was 0.986 for each year of age. Irradiation of one Gy increased survival time by 1.015 times. Chemoimmunotherapy (dose of ACNU and interferon beta) could not be confirmed as an effective covariant.

Adult↗

PubMed1996

[Comparative study on the efficacy of ritipenem acoxil and cefotiam hexetil in chronic lower respiratory tract infections by the double-blind method].

To objectively evaluate the efficacy, safety and usefulness of the newly developed penem oral antibiotic, ritipenem acoxil (RIPM-AC), against chronic lower respiratory tract infections, we conducted a multi-center double-blind comparative study using cefotiam hexetil (CTM-HE) as a control drug. RIPM-AC was orally administered at 200 mg, and CTM-HE at 400 mg, t.i.d. for 14 days, in principle. The results were as follows: The total number of patients enrolled in this trial was 202, of which 151 cases (RIPM-AC group: 75, CTM-HE group: 76) were evaluable for clinical efficacy. 1. The clinical efficacy rates (excellent+good) were 85.3% (64/75) in the RIPM-AC group and 80.3% (61/76) in the CTM-HE group. There was no significant difference between the two groups, hence the clinical equivalency of RIPM-AC to CTM-HE was demonstrated. 2. In the patients enrolled in the evaluation of clinical efficacy, the eradication rates of the causative organisms were 50.0% (13/26) in the RIPM-AC group and 75.0% (18/24) in the CTM-HE group, with no significant difference between the two groups. 3. Side effects were noted in 10 cases (11.0%) of the RIPM-AC group and 10 cases (10.9%) of the CTM-HE group. Abnormal laboratory test findings were observed in 8 cases(9.5%) of the RIPM-AC group and in 14 cases (16.7%) of the CTM-HE group. There were no significant differences between the two groups in the incidence of side effects and abnormal laboratory test findings. In the safety evaluation, RIPM-AC was judged to be safe in 73 cases (80.2%) and CTM-HE in 71 cases (77.2%), with no significant difference. 4. The usefulness rates (markedly useful+useful) were 79.5% (62/78) in the RIPM-AC group and 76.9% (60/78) in the CTM-HE group. There was no significant difference between the two groups. Since RIPM-AC showed clinical efficacy similar to those of CTM-HE and posed no particular safety problems, it is expected to be a useful antibiotic for the treatment of chronic lower respiratory tract infections.

Adult↗

PubMed1996

[Detectability of simulated nodules on chest phantom by Fuji computed radiography: comparison of different nodule sizes, configurations and tube voltages].

The detectability of simulated nodules placed on a chest phantom and shown on FCR images has been studied. Different tube voltages (130 kVp, 100 kVp), presence or absence of compensation filter, various sites and different sizes (5 mm/10 mm) and configurations (spherical or broad based) of the nodule were examined. 112 FCR chest phantom images were evaluated by ten radiology specialists utilizing ROC analysis. The detection rate for nodules was influenced in general by the site. The detection rate was as follows in decreasing order: intercostal, overlaid with one rib, two ribs, diaphragm and heart. Detection of nodules of 10 mm in height was mainly influenced by the density of the lung where the nodule was located, whereas that of nodules of 5 mm in height was more dependent on the site of the nodule, probably greatly influenced by the amount of structure mottle. Spherical nodules of 5 mm in height were more frequently recognized than the broad-based ones. High kVp (130 kVp) resulted in a higher detection rate for both sizes of nodules than low kVp (100 kVp). Detection of spherical nodules overlying the heart or diaphragm was improved with the use of a compensation filter.

Humans↗

PubMed1995

A downstream target of RHO1 small GTP-binding protein is PKC1, a homolog of protein kinase C, which leads to activation of the MAP kinase cascade in Saccharomyces cerevisiae.

The RHO1 gene in Saccharomyces cerevisiae encodes a homolog of the mammalian RhoA small GTP-binding protein, which is implicated in various actin cytoskeleton-dependent cell functions. In yeast, Rho1p is involved in bud formation. A yeast strain in which RHO1 is replaced with RhoA shows a recessive temperature-sensitive growth phenotype. A dominant suppressor mutant was isolated from this strain. Molecular cloning of the suppressor gene revealed that the mutation occurred at the pseuodosubstrate site of PKC1, a yeast homolog of mammalian protein kinase C. Two-hybrid analysis demonstrated that GTP-Rho1p, but not GDP-Rho1p, interacted with the region of Pkc1p containing the pseudosubstrate site and the C1 domain. MKK1 and MPK1 encode MAP kinase kinase and MAP kinase homologs, respectively, and function downstream of PKC1. A dominant active MKK1-6 mutation or overexpression of MPK1 suppressed the temperature sensitivity of the RhoA mutant. The dominant activating mutation of PKC1 suppressed the temperature sensitivity of the RhoA mutant. The dominant activating mutation of PKC1 suppressed the temperature sensitivity of two effector mutants of RHO1, rho1(F44Y) and rho1(E451), but not that of rho1(V43T). These results indicate that there are at least two signaling pathways regulated by Rho1p and that one of the downstream targets is Pkc1p, leading to the activation of the MAP kinase cascade.

Amino Acid Sequence↗

PubMed1995

Age-associated change of 8-hydroxyguanine repair activity in cultured human fibroblasts.

8-hydroxyguanine (8-OH-Gua) is a major oxidative DNA damage product. Its repair activity was determined in the human fibroblast cell line, TIG-3, during the aging process. The repair activity increased in the first part of the aging process and decreased in the latter part. The highest repair activity was observed at the age of 30 PDL. These results suggest that the defense capacity for replication errors due to oxidative DNA damage increases greatly when the cells are rapidly dividing.

Base Sequence↗