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Biomedical subjects

T Kubota

Publications and source records attributed to T Kubota.

At least 307 records · Page 17Linked to original sources
PubMed1999

Comparative study of retinal nerve fiber layer damage in Japanese patients with normal- and high-tension glaucoma.

PURPOSE: To look for possible differences in the pattern of retinal nerve fiber layer (RNFL) damage induced by normal- and high-tension glaucoma. METHODS: The study included randomly selected eyes from 27 patients with open-angle, high-tension glaucoma (mean age, 54.7 +/- 15.0 years; range 21-74 years) and from 19 age-matched patients with normal-tension glaucoma (mean age, 55.7 +/- 11.9 years; range 35-83 years). Eyes were examined using scanning laser polarimetry. RESULTS: The ratio between the superior and inferior quadrant thickness, or symmetry, was significantly lower in patients with high-tension glaucoma (1.00 +/- 0.22) than in patients with normal-tension glaucoma (1.18 +/- 0.32). Similarly, the ratio of the superior to the nasal quadrant thickness was significantly lower in patients with high-tension glaucoma (1.56 +/- 0.38) than in patients with normal-tension glaucoma (1.80 +/- 0.29). No statistically significant differences in the other parameters were detected between the two groups. CONCLUSION: These results show that the pattern of RNFL change is different in patients with high- and low-tension glaucoma. The thickness of the RNFL is reduced symmetrically in the superior and inferior quadrants in high-tension glaucoma, whereas a more localized defect on the inferior RNFL occurs in normal-tension glaucoma.

Adult↗
PubMed1999

[Relation between human papilloma virus DNA and expressions of p53 and p21 proteins in cervical lesions].

Oncogenic types of human papilloma virus (HPV) are known to be closely associated with cervical carcinoma. On the other hand, the oncogenic process is associated with various abnormalities in the mechanisms of cellular regulation. In this study, we detected the expressions of p53 and p21 proteins in cervical lesions by immunohistochemical techniques, and examined the relationship with HPV infection as well as the clinical usefulness of the results. Cervical biopsy specimens from 107 cases of cervical lesions were studied. HPV-DNA was detected by the hybrid capture method using probe A for low oncogenic types and probe B for high oncogenic types. Anti p21, anti-p53 antibodies were used to perform immunostaining. Point mutation in the p53 gene was analyzed by the DGGE method. High oncogenic HPV types were detected at high frequencies in CIN and SCC. In lesions associated with high oncogenic HPV, p53 protein was detected in 33.4% of the lesions and p21 protein in 36.3%. The p53 gene was analyzed in all cases, and point mutation was not detected. No relation was detected between HPV infection and p53/p21 protein expression. Since mutation was not found in the p53 gene, the p53 protein expressed was considered to be wild-type, which is suspected to play a role in inhibiting disease progression in some cases.

DNA, Viral↗
PubMed1999

Immunohistochemical localization of tenascin and ki-67 nuclear antigen in human endometrium throughout the normal menstrual cycle.

To elucidate the possible regulation of endometrial growth, we investigated the expression of tenascin, an extracellular matrix protein associated with cell proliferation and morphogenetic events, in relation to the mitotic marker ki-67 antigen in human endometrium throughout the menstrual cycle. The endometrial tissue was obtained from women with regular menstruation undergoing hysterectomy due to benign uterine disease. Cryostat sections were subjected to double immunohistochemistry to detect both tenascin and ki-67. During the proliferative phase, an intense deposition of tenascin fibrils occurred in the extracellular matrix of the stroma immediately subjacent to the uterine epithelium that showed the highest proportion of ki-67 positive cells. In the secretory phase, the amount of tenascin expression and the proliferative index of the epithelium were markedly reduced. The topological immunoreactivity of tenascin, however, was clearly related to ki-67 localization close to the tortuous endometrial gland and spiral artery. Expression of tenascin, showing changes depending on the menstrual phase, appears to be influenced by ovarian steroid hormones, and it might play a role in regulating human endometrial development by interaction with mitotic cells.

Adult↗
PubMed1998

Effect of genetic differences in omeprazole metabolism on cure rates for Helicobacter pylori infection and peptic ulcer.

BACKGROUND: Omeprazole is metabolized by S-mephenytoin 4'-hydroxylase (CYP2C19) in the liver. In persons with a poor-metabolizer genotype for CYP2C19, the therapeutic efficacy of omeprazole may be increased. OBJECTIVE: To investigate whether CYP2C19 genotype status is associated with cure rates for Helicobacterpylori infection and peptic ulcer achieved by using dual therapy with omeprazole and amoxicillin. DESIGN: Prospective cohort study. SETTING: University hospital and health service center in Hamamatsu, Japan. PATIENTS: 62 patients with peptic ulcer and H. pylori infection. INTERVENTION: Omeprazole and amoxicillin. MEASUREMENTS: CYP2C19 genotype status and cure rates for H. pylori infection and peptic ulcer. RESULTS: Cure rates for H. pylori infection were 28.6% (95% CI, 13.1% to 48.7%), 60% (CI, 38.6% to 83.0%), and 100% (CI, 66.4% to 100%) in the rapid-, intermediate-, and poor-metabolizer groups, respectively. Healing rates for both duodenal and gastric ulcer in the three groups were roughly parallel with cure rates for H. pylori infection. CONCLUSION: The results of the genotyping test for CYP2C19 seem to predict cure of H. pylori infection and peptic ulcer in patients who receive dual therapy with omeprazole and amoxicillin.

Adult↗
PubMed1998

Concomitant caudate lobe resection as an option for donor hepatectomy in adult living related liver transplantation.

In this article, we describe a successful adult living related partial liver transplantation (LRLT) using the left lobe with the left-side caudate lobe (the Spiegel lobe and the left side of the paracaval portion). The size of the donor's left lobe was 29% of the recipient's standard liver volume and did not seem to meet our criteria for adult-to-adult LRLT. However, the donor had a thick left-side caudate lobe. The estimated volume of the left lobe with the left-side caudate lobe was 32%, which met our criteria for the adult recipient. The recipient's CT scan on day 87 after transplantation showed the preserved blood flow and no biliary congestion in the left-side caudate lobe, which suggests maintenance of lobe function. This procedure may be an option for adult-to-adult LRLT in which the donor has a thick left-side caudate lobe.

Adult↗
PubMed1998

Site-directed mutational analysis for the ATP binding of DnaA protein. Functions of two conserved amino acids (Lys-178 and Asp-235) located in the ATP-binding domain of DnaA protein in vitro and in vivo.

DnaA protein, the initiator of chromosomal DNA replication in Escherichia coli, is activated by binding to ATP in vitro. We introduced site-directed mutations into two amino acids of the protein conserved among various ATP-binding proteins and examined functions of the mutated DnaA proteins, in vitro and in vivo. Both mutated DnaA proteins (Lys-178 --> Ile or Asp-235 --> Asn) lost the affinity for both ATP and ADP but did maintain binding activity for oriC. Specific activities in an oriC DNA replication system in vitro were less than one-tenth those of the wild-type protein. Assay of the generation of oriC sites sensitive to P1 nuclease, using the mutated DnaA proteins, revealed a defect in induction of the duplex opening at oriC. On the other hand, expression of each mutated DnaA protein in the temperature-sensitive dnaA46 mutant did not complement the temperature sensitivity. We suggest that Lys-178 and Asp-235 of DnaA protein are essential for the activity needed to initiate oriC DNA replication in vitro and in vivo and that ATP binding to DnaA protein is required for DNA replication-related functions.

Adenosine Triphosphate↗
PubMed1998

Ligand for peroxisome proliferator-activated receptor gamma (troglitazone) has potent antitumor effect against human prostate cancer both in vitro and in vivo.

Troglitazone, a thiazolidinedione derivative, is a widely used antidiabetic drug that binds and activates peroxisome proliferator-activated receptor gamma (PPARgamma) and enhances insulin sensitivity. It induces differentiation of adipocytes, which highly express PPARgamma. We report that human prostate cancer cells expressed PPARgamma at prominent levels and normal prostate tissues had very low expression. Dose-response clonogenic assays of the PC-3 prostate cancer cell line with troglitazone showed an antiproliferative effect (ED50, 3 x 10(-7) M) and other PPARgamma ligands (BRL49653: ED50, 8 x 10(-8) M; 15-deoxy-delta12,14-prostaglandin J2: ED50, 2 x 10(-6) M; ciglitizone: ED50, not reached; indomethacin: ED50, not reached) showed similar effects. Combinations of troglitazone and a ligand specific for either retinoid X receptor or retinoic acid receptor did not show a synergistic effect. Pulse-exposure to troglitazone (10(-5) M) for different durations showed that 4 days of pulse-exposure to the agent irreversibly inhibited 50% clonal growth of PC-3 cells. Interestingly, PC-3 cells cultured with troglitazone (10(-5) M) showed dramatic morphological changes both by light and electron microscopy, suggesting that the cells became less malignant. Nevertheless, troglitazone did not affect either the cell cycle or several markers of differentiation. LNCaP cells constitutively produced prostate-specific antigen, and levels were markedly enhanced by all-trans-retinoic acid. Troglitazone (10(-5) M, 4 days) decreased by 50% the levels of prostate-specific antigen produced by these cells. In vivo treatment of PC-3 tumors growing in male BNX triple immunodeficient mice with oral troglitazone (500 mg/kg/day) produced significant inhibition of tumor growth (P = 0.01). The only objective side effect of troglitazone in mice was the elevation of serum transaminases. Short-term culture of four surgically obtained human prostate cancer tumors with troglitazone (10(-5) M, 4 days) produced marked and selective necrosis of the cancer cells (about 60%) but not the adjacent normal prostate cells. Taken together, these results suggest that troglitazone may be a useful therapeutic agent for the treatment of prostate cancer, especially in the setting of low disease burden.

Animals↗
PubMed1998

19-nor-26,27-bishomo-vitamin D3 analogs: a unique class of potent inhibitors of proliferation of prostate, breast, and hematopoietic cancer cells.

Vitamin D3 [1,25-dihydroxyvitamin-D3 (1,25(OH)2D3)] modulates the proliferation and differentiation of many cell types. Analogs of 1,25(OH)2D3 that have greater potency may become adjuvant therapy for breast and prostate cancers, myelodysplastic syndrome, acute myelogenous leukemia in remission and other cell types, especially in the setting of low disease burden. A new class of analogs of 1,25(OH)2D3 has been synthesized that has a novel 19-nor motif, as well as incorporating many structural elements previously shown to increase potency. These analogs were examined for their effects on prostate cancer cell lines (PC-3, LNCaP, and DU 145), a human breast cell line (MCF-7), and an acute myeloid leukemia cell line (HL-60). Dose-response clonogenic studies showed that each of these analogs had more potent antiproliferative activities against the cancer cells than 1,25(OH)2D3, and 1,25-(OH)2-16,23Z-diene-26,27-bishomo-19-nor-D3 (Ro 27-2014) was the most potent analog [10-fold increased activity compared to 1,25(OH)2D3]. Further studies were performed using Ro 27-2014. Pulse-exposure studies showed that a 5-day pulse-exposure to Ro 27-2014 (10(-7) M) in liquid culture was adequate to achieve a 50% inhibition of MCF-7 clonal growth in soft agar in the absence of the analog, suggesting that the growth inhibition mediated by the analog was irreversible. Cell cycle analyses using MCF-7 cells showed that Ro 27-2014 (10(-7) M for 4 days) induced a significant increase in the number of cells in G0-G1 (72.8+/-8.9% versus 49.9+/-3.5% in control cells), with a concomitant decrease in the percent of cells in S phase (13.1+/-6.2% versus 35.8+/-3.5% in control cells). The chief toxicity of vitamin D3 compounds is hypercalcemia, and therefore, we examined calcemic activity of Ro 27-2014 in mice and found it not to induce hypercalcemia at doses of 0.05 microg i.p. three times per week. In contrast, the same dose of a 19-nor vitamin D3 compound with 6 fluorines on the side chain (1,25-(OH)2-16-ene-23-yne-26,27-F6-19-nor-D3), although also having potent anticancer activity, caused severe hypercalcemia (18 mg/dl). In summary, 19-nor vitamin D3 compounds with desaturation and lengthening of their side chains result in a series of compounds with a good therapeutic index, having potent anticancer activity and low toxicity.

Animals↗
PubMed1998

Transcription factor RTEF-1 mediates alpha1-adrenergic reactivation of the fetal gene program in cardiac myocytes.

Alpha1-adrenergic receptor stimulation induces cardiac myocytes to hypertrophy and reactivates many fetal genes, including beta-myosin heavy chain (betaMyHC) and skeletal alpha-actin (SKA), by signaling through myocyte-specific CAT (M-CAT) cis elements, binding sites of the transcriptional enhancer factor-1 (TEF-1) family of transcription factors. To examine functional differences between TEF-1 and related to TEF-1 (RTEF-1) in alpha1-adrenergic reactivation of the fetal program, expression constructs were cotransfected with betaMyHC and SKA promoter/reporter constructs in neonatal rat cardiac myocytes. TEF-I overexpression tended to transactivate a minimal betaMyHC promoter but significantly interfered with a minimal SKA promoter. In contrast, RTEF-1 transactivated both the minimal betaMyHC and SKA promoters. TEF-1 and RTEF-I also affected the alpha1-adrenergic response of the betaMyHC and SKA promoters differently. TEF-1 had no effect. In contrast, RTEF-1 potentiated the alpha1-adrenergic responses of the SKA promoter and of a -3.3-kb betaMyHC promoter. To determine why the promoters responded differently to TEF-1 and RTEF-1, promoters with mutated M-CAT elements were tested in the same way. The betaMyHC promoter required an intact M-CAT element to respond to TEF-1 and RTEF-1, whereas the SKA promoter M-CAT was required for the TEF-1 response but not for the RTEF-1 response, suggesting that SKA promoter-specific cofactors may be involved. By competition gel shift assay, the M-CAT of the minimal betaMyHC promoter had a lower affinity than that of the SKA promoter, which partly explains the different responses of these promoters to TEF-1. These results highlight functional differences between TEF-1 and RTEF-1 and suggest a novel function of RTEF-1 in mediating the alpha1-adrenergic response in hypertrophic cardiac myocytes.

Actins↗
PubMed1998

The initiator function of DnaA protein is negatively regulated by the sliding clamp of the E. coli chromosomal replicase.

The beta subunit of DNA polymerase III is essential for negative regulation of the initiator protein, DnaA. DnaA inactivation occurs through accelerated hydrolysis of ATP bound to DnaA; the resulting ADP-DnaA fails to initiate replication. The ability of beta subunit to promote DnaA inactivation depends on its assembly as a sliding clamp on DNA and must be accompanied by a partially purified factor, IdaB protein. DnaA inactivation in the presence of IdaB and DNA polymerase III is further stimulated by DNA synthesis, indicating close linkage between initiator inactivation and replication. In vivo, DnaA predominantly takes on the ADP form in a beta subunit-dependent manner. Thus, the initiator is negatively regulated by action of the replicase, a mechanism that may be key to effective control of the replication cycle.

Adenosine Triphosphate↗
PubMed1998

Study on myofibroblast differentiation in the stromal cells of Wharton's jelly: expression and localization of alpha-smooth muscle actin.

To confirm the characteristics of the stromal cells of Wharton's jelly, we investigated the morphological changes in these cells during each trimester of pregnancy. We evaluated the cytoskeletal features of these cells by examining immunohistochemically the localization of one of the contractile proteins, alpha-smooth muscle actin (ASMA). After the second trimester, the stromal cells of Wharton's jelly were stained with ASMA antibody, exhibited the ultrastructural characteristics of the myofibroblasts, and began to express numerous microfilaments in the cytoplasm. Postembedding immunogold labeling detected immunoreactivity for ASMA on these microfilaments. The finding indicated that the stromal cells of Wharton's jelly undergo a time-dependent maturation involving the differentiation of myofibroblasts during the last 6 months of pregnancy. These cells possess a contractile function that may help to protect the umbilical vessels from compression, considering that ASMA was detected in the microfilamentous bundles.

Actins↗
PubMed1998

Effects of tumor necrosis factor gene polymorphisms on patients with congestive heart failure. VEST Investigators for TNF Genotype Analysis. Vesnarinone Survival Trial.

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) is known to be elevated in patients with congestive heart failure (CHF). Two biallelic polymorphisms have been identified in the TNF gene locus: one in the promoter region of TNF-alpha (TNFA1/2), and the other in the first intron of TNF-beta (TNFB1/2). Both TNFA2 and TNFB2 alleles are associated with high TNF-alpha production in vitro and susceptibility to inflammatory diseases. Given the importance of TNF-alpha in the pathogenesis of CHF, we studied the prevalence of TNF gene polymorphisms in CHF patients and the correlation of genotypes to in vivo TNF-alpha levels. METHODS AND RESULTS: TNFA and TNFB genotypes were determined by the polymerase chain reaction-restriction fragment length polymorphism technique. There were no differences in the TNF allele frequencies between CHF (n=229; TNFA1/2=0.84/0.16, TNFB1/2=0.33/0.67) and control subjects (n=139; TNFA1/2=0.84/0.16, TNFB1/2=0.32/0.68). In 211 patients with CHF, circulating levels of TNF-alpha and the soluble receptors type I and type II were measured by ELISA: 6.18+/-3.59 pg/mL, 1768+/-761 pg/mL, and 4484+/-1750 pg/mL, respectively. There were no correlations between TNFA or TNFB genotypes and circulating levels of TNF-alpha or its soluble receptors in the CHF patients. CONCLUSIONS: Despite their association with other inflammatory diseases, neither TNFA nor TNFB polymorphisms are related to the presence of CHF or the elevation of circulating TNF-alpha. Thus, other factors may be more important in determining the circulating levels of TNF-alpha in CHF.

Adult↗
PubMed1998

Linkage of mutant alleles of CYP2C18 and CYP2C19 in a Japanese population.

The coincidence of mutated alleles of CYP2C18 and CYP2C19 was studied in 154 Japanese subjects. The mutant alleles of CYP2C18 studied were CYP2C18m1 (T204 --> A substitution in exon 2) and CYP2C18mFR (A-460 --> T substitution in the 5'-flanking region), and those of CYP2C19 were CYP2C19m1 (G689 --> A substitution in exon 5) and CYP2C19m2 (G636 --> A substitution in exon 4). They were identified by polymerase chain reaction and restriction fragment length polymorphism. The results indicate that genotypes of CYP2C18m1 and CYP2C18mFR are completely coincident with those of CYP2C19m2 and CYP2C19m1, respectively. The finding suggests that the mutations of CYP2C18 and CYP2C19 examined in the present study are very closely linked with each other (i.e. CYP2C18m1 vs CYP2C19m2 and CYP2C18mFR vs CYP2C19m1), at least in a Japanese population.

Alleles↗
PubMed1998

The gene for component-II of botulinum C2 toxin.

The gene encoding component-II of the Clostridium botulinum C2 toxin was cloned from the chromosomal DNA of C. botulinum type C strain (C)-203U28, and the nucleotide sequence was determined. The gene (bc2h) encodes a protein with 721 amino acid residues and is located at 247 bp downstream of the gene for component-I. The N-terminal 16 amino acids were identical to those obtained by analysis of the purified component-II toxin. The ORF for bc2h had only 39% homology at the amino acid level with the C.perfringens iota-Ib protein and an ATP/GTP binding site which is present in the iota-Ib protein is missing from the protein encoded by bc2h. Both genes had a homologous region that predicts a transmembrane segment.

Amino Acid Sequence↗
PubMed1998

Occlusive effects of lactic acid-glycolic acid copolymer membrane on gingival fibroblasts in vitro.

The cell occlusive effects on human gingival fibroblasts of degradable lactic acid-glycolic acid copolymer membranes (noncoated membranes) and membranes coated with a sucrose ester of fatty acid (coated membranes) were studied and compared with those of expanded polytetrafluoroethylene (e-PTFE) membranes. The membranes were immersed in a culture medium periodically for 21 days and interposed into a chemotaxis chamber, and the fibroblasts then were cultured in the chamber for another 7 days. The passage rate of cells through the membranes was calculated and the change in surface structure of each membrane after immersion for 28 days was observed by an environmental scanning electron microscope. The passage rate of coated membranes (3.4+/-2.2%) was significantly lower than that of noncoated (25.7+/-5.1%) at the 28th day whereas the passage rate of e-PTFE membranes was 0.8-1.5%. Many pores were observed on the noncoated membranes before immersion while the coating material covered most of the pores on the coated membranes. The average pore size of the noncoated membranes was larger than that of the coated membranes at day 28. The structure of the e-PTFE membranes underwent no change. The passage rate of the coated membranes was not different from the e-PTFE membranes, suggesting an effect that might be useful for a guided tissue regeneration procedure.

Fibroblasts↗
PubMed1998

Negative chronotropic effect of botulinum toxin on neonatal rat cardiac myocytes.

We demonstrated that botulinum neurotoxin attenuated the spontaneous beating rate of cultured cardiac myocytes. Primary cultured cardiac myocytes were prepared from the ventricles of neonatal Wistar rats (1-3 days old). On 7 days after cell seeding, botulinum toxin type A incorporated into liposomes was added to the culture medium. At a final concentration of 5.0 micrograms/ml, botulinum toxin markedly attenuated the beating rate of cardiac myocytes within 2-4 hours. These results demonstrated the effect of SNARE-complex proteins on the spontaneous beating of cardiac myocytes.

Animals↗