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Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 397 records · Page 22Linked to original sources
PubMed1997

Enzymes involved in DNA synthesis in the testes are regulated by temperature in vitro.

OBJECTIVE: Temperature is considered to be an important local regulating factor of testicular function. We investigated whether a high temperature would affect the activity of DNA polymerases alpha, beta, and gamma (EC2.7.7.7) and DNA topoisomerase I in the testes which are required for germ cell differentiation. METHODS: An in vitro rat testis tissue culture system was used to evaluate the activity of DNA polymerases alpha, beta, and gamma and DNA topoisomerase I after incubation at 31 and 37 degrees C. The expression of proliferating cell nuclear antigen was evaluated immunohistochemically in the testis. RESULTS: Incubation at 37 degrees C significantly reduced the activity of all four enzymes as compared with incubation at 31 degrees C. Reducing the temperature to 31 degrees C after prior incubation at 37 degrees C partially restored DNA polymerase alpha activity. Expression of proliferating cell nuclear antigen demonstrated a reduction in DNA synthesis in the seminiferous tubules after incubation at 37 degrees C CONCLUSION: These findings indicate that a high temperature of 37 degrees C reduces the activity of the enzymes involved in the testicular synthesis of DNA which may cause the impairment of spermatogenesis.

Animals↗
PubMed1997

Immunohistochemical localization of parathyroid hormone-related protein in canine mammary tumors.

Parathyroid hormone-related protein (PTHrP) was localized immunohistochemically in 58 canine mammary tumors (31 malignant, 27 benign) and adjacent normal or hyperplastic mammary tissue. PTHrP immunoreactivity was significantly enhanced by pretreatment with microwave heating in normal and neoplastic tissues. Epithelial cells of hyperplastic and neoplastic mammary tissues, myoepithelial cells, and metaplastic osteoblasts in mammary tumors stained moderately to strongly positive for PTHrP No significant difference between staining intensity for PTHrP and histologic pattern of mammary tumors was found. The presence of PTHrP in normal and neoplastic canine mammary tissues supports a pathophysiological role for PTHrP as a paracrine or autocrine hormone in the mammary gland.

Animals↗
PubMed1997

Lymphocyte-fibroblast interactions.

Chronic inflammatory reactions are usually characterized by inflammatory cell accumulation in the extravascular connective tissue. In such sites, inappropriate activation of circulating or resident lymphocytes becomes self-perpetuating and can lead to chronic tissue destruction. In addition to that, the locally infiltrated lymphocytes should have an opportunity to interact directly with fibroblasts composing the connective tissue. The direct interactions of those different cell types seem to play important roles in lymphocyte lodging and retention in such sites. Thus, for clarification of the immunopathogenesis of the chronic inflammatory diseases, including periodontitis, it is important that the molecular mechanisms involved in the heterotypic cell-cell interactions be revealed. In fact, it has been demonstrated that lymphocytes interact with various non-hematopoietic cells, such as epithelial cells and endothelial cells. Regarding interactions with fibroblasts, it has been shown that IFN gamma-stimulated fibroblasts can regulate the proliferative responses of T-lymphocytes both positively and negatively. Furthermore, activated lymphocytes have demonstrated strong binding ability to various fibroblast cell lines. Blocking experiments utilizing monoclonal antibodies specific to various cell adhesion molecules revealed that very late antigen (VLA) integrins, lymphocyte-function-associated antigen (LFA-1)/intercellular adhesion molecule-1 (ICAM-I), CD44/hyarulonate are, at least in part, involved in lymphocyte-fibroblast interactions. In addition, recent findings raised the possibility that the adhesive interactions between lymphocytes and fibroblasts influenced the various cellular functions of each cell type. In fact, it was recently demonstrated that the adhesive interactions stimulated fibroblasts to increase expression of inflammatory cytokine mRNA. These results strongly suggest that fibroblasts are not merely innocent bystanders but actively participate in local inflammatory reactions by directly interacting with locally infiltrated lymphocytes.

Animals↗
PubMed1997

Nitric oxide production by cultured rat Leydig cells.

Nitric oxide (NO) has emerged as an intracellular and intercellular messenger in a number of biological systems. In the present study, we demonstrated that NO was produced by cultured rat Leydig cells, and that inducible nitric oxide synthase (iNOS) messenger RNA (mRNA) was expressed in Leydig cells. NO was measured as nitrite with the method of Griess. Although unstimulated Leydig cells produce little NO, interleukin-1 beta (IL-1 beta) markedly increased NO production. NO production was inhibited by the NOS inhibitor, NG-monomethyl-L-arginine. Northern blot analysis showed that iNOS mRNA was little expressed in freshly isolated immature Leydig cells, but that iNOS mRNA levels were increased by the addition of IL-1 beta in a dose-dependent manner at the concentration up to 10 ng/ml. The levels of iNOS mRNA were increased as early as 3 h after the addition of IL-1 beta and persisted for up to 24 h. In adult Leydig cells, IL-1 beta stimulated iNOS mRNA expression. Immunocytochemical analysis demonstrated iNOS-like immunoreactivity in the cytoplasm of Leydig cells. These results indicate that NO is produced in Leydig cells and suggest that NO might be involved in the physiological function of Leydig cells.

Animals↗
PubMed1997

Purification and characterization of dipeptidyl aminopeptidase from Aureobacterium sp. WO26.

We isolated a bacterial strain with an enzyme which releases dipeptide from Gly-Arg-p-nitroanilide. The bacterium was tentatively identified as Aureobacterium sp. The enzyme, named AuDAP, was purified and characterized. It was homogenous by SDS-PAGE and IEF, and had a molecular mass of 90,000 Da by SDS-PAGE and 88,000 Da by gel filtration, so it may be a monomer. The isoelectric point was 3.8 and the optimum pH was 10.0. The purified enzyme hydrolyzed Gly-Arg-pNA, a model substrate for DAP I, and Arg-Arg-MNA, a model substrate for DAP III. However, this enzyme did not hydrolyze Gly-Phe pNA, also a model substrate for DAP I. These results suggested that this enzyme did not fall under the classification of mammalian DAPs and was similar to DAP BI from Pseudomonas sp. WO24 and dDAP from Dictyostelium discoideum, although several differences were observed between them. The N-terminal amino acid sequence of this enzyme showed no significant homology to any enzyme and protein, except only for DAP BI.

Dipeptidyl-Peptidases and Tripeptidyl-Peptidases↗
PubMed1997

Purification and characterization of a dipeptidyl carboxypeptidase from Pseudomonas sp. WO24.

A dipeptidyl carboxypeptidase (DCP) activity was detected in cell-free extracts of Pseudomonas sp. WO24. After purification and characterization the enzyme was found to be homogeneous by SDS-PAGE, and had a molecular mass of 74,000 Da by SDS-PAGE and 72,000 Da by gel filtration, indicating that it is monomeric. The isoelectric point was 5.2 and optimum pH was 6.5-7.0. It showed a specific activity of 780 mumol/min/mg, which is the highest of the values shown by known enzymes. The enzyme hydrolyzed angiotensin I to angiotensin II and sequentially released Phe-Arg and Ser-Pro from the C-terminus bradykinin. The DCP could not cleave imido-bonds, Gly-Gly bonds, or tripeptides. The enzymatic activity was completely inhibited by 0.001 mM EDTA and 0.1 mM O-phenanthroline, but it was not affected by general serine and cysteine protease inhibitors. Addition of Zn2+ completely restored the original activity of the inactivated DCP treated with EDTA. These results suggest that this enzyme is a zinc metalloprotease. The characteristics of the purified enzyme are slightly different from those of the DCPs from Escherichia coli, Pseudomonas maltophilia, and Corynebacterium equi, and considerably from those of the DCP from Bacillus pumilus.

Amino Acid Sequence↗
PubMed1997

Detection of interleukin-1 and interleukin-6 on cryopreserved bovine mammary epithelial cells in vitro.

This investigation was performed to determine whether primary cultures of mammary cells from lactating cows would sustain production of interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF), and express mRNA for cytokines interleukin (IL)-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-10, interferon (INF)-tau, TNF-alpha, and granulocyte-macrophage colony-stimulating factor (GM-CSF) by the reverse transcription-polymerase chain reaction (RT-PCR) in vitro. Cryopreserved mammary epithelial cells collected from cows at 1 week post calving were plated in collagen-coated 24-well culture plates (250,000 cells/well). IL-1 and IL-6 productions were measured using a A375 cell growth inhibition assay and a 7TD1 hybridoma proliferation assay, respectively. Production of IL-1 was demonstrated in mammary epithelial cells cultured with unsupplemented medium, but was not produced by cells cultured in medium supplemented with fetal bovine serum. IL-6 production in the conditioned medium was continued at steady level until day 14, whereas IL-6-like bioactivity was not detected in medium alone. TNF-like activity was not detectable in any experiments. This study also demonstrated the expression of mRNA for multiple cytokines including IL-1alpha, IL-1beta, IL-6, IL-10, TNF-alpha, and GM-CSF by RT-PCR in mammary cell cultures. The results indicate that bovine mammary epithelial cells of lactating cows produce IL-1 and IL-6 and have gene expression for multiple cytokines. This in vitro model will be useful to investigate the function and regulation of IL-1 and IL-6 in the lactating mammary gland.

Animals↗
PubMed1997

Distinct promoter sequences of two precursor genes for salmon gonadotropin-releasing hormone in masu salmon.

Two types of genes encode salmon gonadotropin-releasing hormone (sGnRH), which is thought to act on both sexual maturation and reproductive behavior, in salmonids. We characterized the two sGnRH genes (sGnRH-I and -II) and their upstream regions in masu salmon, Oncorhynchus masou, since such information is a prerequisite for molecular approaches to salmon reproduction. The two genes have similar exon-intron structures composed of four exons and three introns. Sequence analyses of the two genes showed that coding regions are highly conserved, but upstream regions are distinctively divergent. In the upstream regions, only the sGnRH-II gene has a large palindromic sequence, which has been proposed to be involved in control of transcription via estrogen receptors. In contrast, the sGnRH-I gene is missing the large palindromic sequence, but has three distinct palindromes in the upstream region. These results may suggest divergent transcription regulatory mechanisms between the two sGnRH genes in masu salmon. The differences in the upstream regions of sGnRH genes in Atlantic salmon (Salmo salar), sockeye salmon (Oncorhynchus nerka) and masu salmon are discussed with respect to the evolution of sGnRH genes in salmonid fish.

Animals↗
PubMed1997

Geranylgeranylacetone and cetraxate hydrochloride increase UDP-galactosyltransferase activity in rat gastric mucosa.

UDP-galactosyltransferase (UDP-Gal-T) is a key enzyme in the synthesis of mucus glycoprotein which plays an important role in gastric mucosal defensive mechanisms. Analysis of gastric UDP-Gal-T activity should clarify the mechanisms of the action of antiulcer drugs regarding gastric defensive factors. Here, we examined UDP-Gal-T activity in rat gastric mucosa treated with the antiulcer drugs geranylgeranylacetone (GGA) and cetraxate hydrochloride (CET). The effects of coadministration of indomethacin and exogenous administration of prostaglandins (PGs) were also studied. GGA and CET significantly increased UDP-Gal-T activity, and coadministration of indomethacin inhibited the increase of enzyme activity. UDP-Gal-T activity level with GGA was significantly higher than the control level, even in the presence of indomethacin. With CET, however, this was not the case. Among PGs, PGE1 significantly increased enzyme activity. Concomitant administration of PGE1 and GGA or CET increased UDP-Gal-T activity even with indomethacin to the levels achieved when these antiulcer drugs were administered without indomethacin. Our findings suggest that GGA and CET exert antiulcer effects by increasing mucus glycoprotein synthesis and that endogenous PG synthesis may be involved in this process. However, mechanisms not mediated by endogenous PGs may also exist in the stimulatory action of GGA on UDP-Gal-T activity.

Animals↗
PubMed1997

Odontogenic myxofibroma arising from the periodontal ligament in the maxillary molar region.

A rare case of odontogenic myxofibroma, which arose from the periodontal ligament and expanded into the oral cavity resulting in an epulis-like lesion in a 52-year-old man, is reported including details of studies using lectin histochemistry, transmission electron microscopy (TEM), and immunohistochemistry. Most of the tumor cells, which appeared spindle-like with abundant rough endoplasmic reticulum and some microfilaments by TEM, showed immunoreactivity for mesenchymal markers. Some tumor cells, which were polygonal and contained many microfilaments and some filament bundles, were immunoreactive for muscle markers. The present case was considered to consist of many fibroblasts and some myofibroblasts.

Bicuspid↗
PubMed1997

[Development of a regimen comprehension scale].

Whether elderly patients can take prescription drugs as directed by a physician is often unclear. So elderly patients could receive adequate instruction regarding their medications, we developed a regimen comprehension scale (RCS) with simple questions regarding information on dosage and administration. This information was written on the outside of the paper bags in which the medications are usually dispensed. The subjects were 21 healthy volunteers (11 men and 10 women, averaged age 38.3 +/- 11.2 years) and 17 inpatients (9 men and 8 women, averaged age 73.4 +/- 6.8 years). Five kinds of drugs, which differed with respect to dosage and administration were used. The subjects were questioned in an interview about taking the five drugs and their regimen comprehension was assessed with the RCS (maximum score: 10 points, lowest score: 10 points. Then regimen comprehension was classified into 4 grades: normal (10), caution needed (9 or 8), training needed (7 or 6), and assistance needed (5 or less). In addition, intelligence was tested with the revised version of Hasegawa's dementia scale (HDS-R). Eight of the 21 healthy volunteers (38%) and 13 of the 17 elderly patients (76%) misunderstood some aspects of the regimens written on the paper bags. The regimen comprehension was classified as "normal", "caution needed", and "training needed" in 13, 7, and 1 of the healthy volunteers, respectively, it was classified as "normal", "caution needed", "training needed", and "assistance needed" in 4, 4, 4, and 5 elderly patients, respectively. The five elderly patients classified as "assistance needed" were suspected to have dementia because they had scores on the HDS-R of 21 or less. A significant positive correlation (r = 0.797) was noted between scores on the HDS-R and on the RCS. When treating elderly patients with chronic disease (for example, hypertension) it is important to evaluate their regimen comprehension with an index such as the RCS to determine the need for medication counseling before the start of a medication regimen.

Adult↗
PubMed1997

[Metastatic tumor to the penis from lung and pancreas cancer: report of two cases].

Neoplasms metastasizing to the penis are uncommon, and occur at the end stage of carcinoma. We describe two patients with a metastatic lesion to the penis from lung squamous cell carcinoma and pancreatic adenocarcinoma. We reviewed 101 cases with secondary penile tumor. The prognosis of secondary penile tumor is extremely poor.

Adenocarcinoma↗
PubMed1997

[The effect of cerebral perfusion pressure on cerebral blood flow in the rhesus monkey during sevoflurane anesthesia].

The effect of cerebral perfusion pressure on cerebral blood flow (CBF) was studied under the normocapnic condition in the rhesus monkey under sevoflurane anesthesia. CBF was measured by means of positron emission tomography technique. After the measurement of CBF at 0.5% sevoflurane as control, the measurement was repeated at 2.0% sevoflurane (1 MAC), when blood pressure was kept at a half of the control value. The measurement was also repeated at the same sevoflurane concentration, when the mean blood pressure was restored with the infusion of angiotensin II. Average CBF as well as regional CBFs were compared between two different mean blood pressures at 2.0% sevoflurane. Average CBF increased significantly (+35%), when the mean arterial pressure was increased by the angiotensin II infusion. All the regional CBFs except at frontal cortex increased significantly (+ about 30%) in response to the increase in the mean arterial pressure. The increase in occipital CBF was greatest (+52%). We conclude that CBF during sevoflurane anesthesia up to 2.0% might become dependent on the cerebral perfusion pressure, indicating the compromised autoregulation of CBF in the rhesus monkey.

Anesthesia, Inhalation↗
PubMed1997

[Trial of radiation and cisplatin, carboplatin combination chemotherapy for advanced cancer (W-platinum chemoradiotherapy].

Cisplatin was reported to be an effective radiation sensitizing agent. The effect was also reported to depend on dose intensity. But the incidence of complication was demonstrated in the relationship with the dose escalation curve of anti-cancer agent. The major side effect of CDDP was occasionally serious, as in renal toxicity or bone marrow suppression. W-Platinum is the trial of concurrent chemoradiotherapy. Cisplatin and its derivative, Carboplatin, were selected as effective radiation sensitizing agents and to obtain high-dose intensity and additive cytotoxicities by interaction between the two drugs. Concomitant administration of two platinum anti-cancer agents has the advantage of reduction of side effects compared with administration of single anti-cancer agents to the same degree. The first case was a recurrence of epipharyngeal cancer after 3 courses of chemotherapy, including CDDP or CBDCA. This case was suspected to be cancer-resistant to CDDP. The second case was post-operative residual lung cancer. The pre-operative diagnosis was stage III A. A poor prognosis was expected. This case was disease-free and alive for 1 year after W-Platinum administration. The most frequent complication was bone marrow suppression. Patients were rescued from bone marrow suppression with administration of G-CSF. Renal toxicity could be suppressed with sufficient hydration.

Adenocarcinoma↗
PubMed1997

[Clinical statistics on in-patients and operations during a 20-year period (1975-1994) at Department of Urology, Kansai Medical University].

The patients, diseases and operations experienced between 1975 and 1994 in our department were statistically analyzed. The numbers of in-patients and operations have been increasing since 1977. During these 20 years, endoscopic surgery has replaced many open surgical procedures. The introduction of extracorporeal shock wave lithotripsy has dramatically changed the therapeutic modality for urolithiasis, and decreased of the necessity of open surgery.

Female↗
PubMed1997

Retroviral infection in peripheral mononuclear cells in patients with IgA nephropathy.

An etiologic agent directly linked to the development of IgA nephropathy (IgAN) has not been identified, despite the fact that various causes, including viral infections, have been implicated in the pathogenesis of this disease. Human immunodeficiency virus (HIV) infection has been linked with the development of IgAN in several clinical studies, and retroviral infection may be associated with the pathogenesis of IgAN in some patients. The incidence of IgAN has been found to possess distinct geographical distributions, and familial genetic clustering. To determine if retroviral infection is associated with IgAN in a large population of patients, genomic DNA from peripheral blood mononuclear cells from 90 patients seronegative for HIV and human T-cell leukemia virus type 1 (HTLV-1) (37 IgAN, 33 other glomerulonephritis, and 20 healthy controls) was evaluated by nested PCR using a pan-lentivirus-specific primer set (PLSPS), targeting the consensus sequence of the lentiviral pol gene. In 37.8% (14 of 37) of the patients with IgAN, the PCR products migrated in parallel with bands produced by PCR of simian immunodeficiency virus (SIV) infected cells. No products of the expected size were detected in the other patient groups (p < 0.0001, Chi-square). These results suggest that exposure to retroviral infection is more common in patients with IgAN, compared with patients with other proliferative glomerulonephritides, or patients without renal disease. These data demonstrate a possible association of IgAN with infection with non-HIV, non-HTLV-1 retrovirus.

Adolescent↗
PubMed1997

Formation of reactive oxygen species by spermatozoa from asthenospermic patients: response to treatment with pentoxifylline.

PURPOSE: We determined the incidence of reactive oxygen species formation by spermatozoa from asthenospermic patients, and the relationship between reactive oxygen species formation and sperm motion parameters. We also assessed the efficacy of in vitro and in vivo pentoxifylline treatment of asthenospermic patients whose spermatozoa generated high reactive oxygen species levels. MATERIALS AND METHODS: Reactive oxygen species formation by spermatozoa from asthenospermic patients and fertile volunteers was measured by chemoluminescence. Reactive oxygen species formation by the sperm preparations was investigated without stimulation (steady state), or after stimulation with N-formyl-methionyl-leucyl-phenylalanine (f-MLP) or phorbol-12-myristate-13-acetate. Spermatozoa from 15 asthenospermic patients whose spermatozoa produced high levels of reactive oxygen species at steady state were treated in vitro with pentoxifylline to determine its effect on reactive oxygen species generation and sperm motion parameters. These same 15 patients and 18 with asthenospermia whose spermatozoa did not produce reactive oxygen species at steady state were treated with pentoxifylline at 2 different dosages (300 and 1,200 mg. daily) to determine its effect on reactive oxygen species generation, sperm motion parameters and sperm fertilizing ability in vivo. RESULTS: When reactive oxygen species formation was detected in the steady state that was not stimulated by f-MLP, the source of reactive oxygen species could be attributed to the spermatozoa themselves. Spermatozoa from 15 of 71 asthenospermic patients generated reactive oxygen species at steady state. Pentoxifylline decreased reactive oxygen species generation by spermatozoa in these patients, and preserved the decrease of curvilinear velocity and beat cross frequency for 6 hours in vitro. For these patients orally administered pentoxifylline failed to decrease reactive oxygen species generation by spermatozoa, and had no effect on sperm motility, sperm motion parameters and sperm fertilizing ability at low dosage (300 mg. daily). However, it increased motility and beat cross frequency at high dosage (1,200 mg. daily) but it had no effect on sperm fertilizing ability. CONCLUSIONS: Stimulation of sperm preparations with f-MLP can identify the source of reactive oxygen species generated at steady state. Among asthenospermic patients there were some whose spermatozoa produced detectable steady state levels of reactive oxygen species. In this group pentoxifylline appeared to be effective for decreasing reactive oxygen species formation and preserving sperm motion parameters in vitro. Orally administered pentoxifylline had no effect at low dosage but it increased sperm motility and some sperm motion parameters without altering sperm fertilizing ability at high dosage.

Fertilization↗