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Biomedical subjects

M Okuda

Publications and source records attributed to M Okuda.

At least 199 records · Page 11Linked to original sources
PubMed1994

[Study of endothelin: distribution in the airway and release from nasal epithelial cells].

In order to clarify the existence and the role of endothelin in the respiratory tract, we investigated the distribution of endothelin in the respiratory mucosa by immunohistochemistry. The endothelin release from cultured nasal epithelial cells of allergic mucosa and polyp mucosa was also studied by RIA. Endothelin was distributed in the epithelium, endothelium of vessels, and submucosal glands in both nasal and bronchial mucosa. Moreover, in bronchial mucosa smooth muscles of bronchus had also positive staining of endothelin. On the other hand, 1.8 x 10(-11) pg of endothelin was released to culture medium from single cultured epithelial cell of allergic nasal mucosa, and 2.8 x 10(-11) pg of endothelin was released to culture medium from that of nasal polyp. These increase of endothelin was correlated with an increase of cultured epithelial cells from both nasal allergy mucosa and nasal polyp, of which the cell number was increased depend on the concentration of FCS. These results indicate that endothelin in the respiratory mucosa acts on not only control of blood flow and air flow, but also has some reaction which was related on the mucosal epithelium such as epithelial cilially movement. Endothelin has some role in inflammation because endothelin was increased more in nasal polyp culture medium than in allergic mucosa culture medium.

Cell Count↗
PubMed1993

Cellular proliferation in the anterior pituitary gland of normal adult rats: influences of sex, estrous cycle, and circadian change.

Proliferative activity of the anterior pituitary gland in 10 week-old male and female rats under normal conditions was investigated by counting mitotic figures and using single and double immunostaining of 5-bromo-2'-deoxyuridine (BrdU), proliferating cell nuclear antigen (PCNA), and six pituitary hormones. To determine which proliferative changes depend on the estrous cycle and circadian changes, respectively, six groups of female and two groups of male rats were studied at various times of day. Additionally, BrdU-incorporated cells were further classified by the six types of hormones they contained, or as immunonegative cells. Cell proliferative activity in the females fluctuated drastically with the highest activity in estrus and the lowest in diestrus. In the males, proliferative activity was at a relatively low level, and was similar to that in females in proestrus or early estrus, with the greater activity at night. Identified by their pituitary hormones, the distribution of the proliferating cells was almost the same in each sex, with prolactin (PRL) cells accounting for the highest proportion, followed by growth hormone (GH) cells, and adrenocorticotropic hormone (ACTH), luteinizing hormone (LH), follicle stimulating hormone (FSH), and thyroid stimulating hormone (TSH) cells. These percentages agreed well with previously reported levels of cell types among all pituitary cells of the rat. It is therefore suggested that the life span and cycle of rat pituitary cells does not differ among cell types. In another test, male and female rats were given BrdU continuously via an osmotic pump for 8 days to compare cell proliferative activity between sexes, exclusive of the influence of estrous cycle and circadian changes. In this way, we were able to demonstrate that the cumulative incorporation of BrdU in females was consistently twice as high as in males over a constant period of time, and to conclude that cell renewal occurs at a doubled rate in the pituitary of female rat.

Animals↗
PubMed1993

HCV-RNA assay in peripheral blood mononuclear cells in relation to IFN therapy.

Hepatitis C virus RNA (HCV-RNA) was serially assayed in the serum and peripheral blood mononuclear cells (PBMC) of 10 patients with chronic hepatitis C who underwent interferon (IFN) therapy, and whether detection of HCV-RNA from PBMC serves as an index of the response of chronic hepatitis C to IFN therapy was evaluated. HCV-RNA was assayed by reversed transcription and polymerase chain reaction using the 5'-noncoding region as a primer. IFN therapy was effective in 3 patients and ineffective in the other 7 patients. HCV-RNA disappeared from the serum during and immediately after the IFN therapy in all 3 patients in whom the therapy was effective and in 3 of 7 patients in whom the therapy was ineffective. HCV-RNA disappeared from PBMC in all 3 patients in whom the therapy was effective, but PBMC HCV-RNA remained positive in 6 of the 7 patients in whom the therapy was ineffective, and the serum HCV-RNA became positive again in 5 of these 6 patients after 6 months. The disappearance of HCV-RNA from PBMC was associated with long-term stabilization of the serum alanine aminotransferase value, so HCV-RNA assay in PBMC is considered to be useful as a prognostic marker of chronic hepatitis C after IFN therapy.

Adult↗
PubMed1993

Decreased cellular toxicity of neomycin in a clonal cell line isolated from LLC-PK1.

We have previously shown in LLC-PK1 cells, that apical membrane enzyme activity was inhibited by aminoglycoside antibiotics (Am. J. Physiol. 254, C251-C257, 1988). In the present study, the relationship between the lethal cytotoxic effect of aminoglycoside and its effect on apical membrane enzyme was examined by establishing aminoglycoside resistant cells. A clonal cell line, LLC-PK1/NRa3, was isolated from parent LLC-PK1 cells in the presence of neomycin. Neomycin inhibited colony formation and increased the number of floating dead cells in parent LLC-PK1 cultures. In contrast, these cytotoxic effects of neomycin were negligible or less pronounced in NRa3 cells, indicating that NRa3 cells were more resistant to neomycin compared with the parent cells. The inhibitory effect of neomycin on apical enzyme activity was significantly weaker in NRa3 cells than in the parent cells. These results suggest that a common mechanism is involved in the aminoglycoside-induced reductions in the apical enzyme activity and in cell viability of LLC-PK1 cells.

Alkaline Phosphatase↗
PubMed1993

Two chronic myelogenous leukaemia cell lines which represent different stages of erythroid differentiation.

We established two cell lines, YN-1 and Y-1K, from the peripheral blood of two chronic myelogenous leukaemia patients in blastic crisis. Characterization of the YN-1 and Y-1K cells revealed that these cells expressed erythroid lineage markers. However, there was a marked difference in the level of gamma-globin mRNA and haemoglobin in YN-1 and Y-1K cells. YN-1 contained approximately 1-5% benzidine-positive staining cells, whereas no benzidine-positive cells were observed in Y-1K cells. Haemoglobin production in YN-1 cells was markedly increased with various chemical inducers of erythroid differentiation, but was not in Y-1K cells. In contrast, Y-1K cells expressed CD34 stem cell antigen and CD41 megakaryocyte-specific antigen. These observations suggested that, although both cell lines were committed to the erythroid lineage, each cell line represented a distinct differentiation stage in the erythroid differentiation programme. Y-1K seemed to correspond to an early stage of cells in erythroid lineage, whereas YN-1 represented a more advanced stage in human erythropoiesis.

Adult↗
PubMed1993

A comparative study of the characteristics of intraepithelial and lamina propria lymphocytes of the human nasal mucosa.

The phenotypes and receptors of the intraepithelial lymphocytes which are a major component of the mucosal immune system are of considerable interest. Intraepithelial lymphocytes, especially those of the intestines, are well documented. The nasal intraepithelial lymphocytes probably play a key role in the immune defense of the entire respiratory tract. However, documentation of these lymphocytes is limited to only a few nondescriptive studies by immunohistological methods. In our previous paper, we examined the subsets of the nasal intraepithelial lymphocytes by two-color flow cytometry after culture with monoclonal antibody against CD3 and PMA. The mucosal immune system, which comprises the lymphoid tissue associated with the mucosal surface, consists of lymphocyte populations from both the epithelium and the lamina propria. In this paper (a sequel to our previous study), we have carried out a comparative study of the intraepithelial lymphocytes and lamina propria lymphocytes of the human nasal mucosa. In the 42 patients (with allergic rhinitis/infectious hypertrophic rhinitis) whom we examined, T lymphocytes were predominant in the epithelium as well as the lamina propria. B lymphocytes were detected only in the lamina propria. CD8+ T cells (suppressor/cytotoxic) and CD4-8- (double-negative) (DN) comprised the major population of the intraepithelial lymphocytes. The CD4+/CD8+ ratio was 0.5 +/- 0.1. In contrast, the lamina propria showed a predominance of CD4+ T cells (helper/inducer), with a CD4+/CD8+ ratio of 1.3 +/- 0.2. CD3 + 4-8- (double-negative T cells) were comparable in number in the epithelium and the lamina propria. CD8+ T cells of the epithelium were predominantly cytotoxic T cells, and CD4+ T cells were predominantly helper T cells. In the lamina propria, CD8+ T cells were predominantly of the suppressor type.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Novel Allylic Oxidation of alpha-Cedrene to sec-Cedrenol by a Rhodococcus Strain.

A bacterial strain, designated KSM-7358, that can use alpha-cedrene for growth was isolated. The strain was identified as a member of the genus Rhodococcus and catalyzed the novel allylic oxidation of alpha-cedrene regiospecifically to produce (R)-10-hydroxycedrene (sec-cedrenol) with a very high yield. alpha-Curcumene was also produced as a possible metabolite of sec-cedrenol. A possible pathway for the microbial conversion of alpha-cedrene to sec-cedrenol and alpha-curcumene is proposed.

Journal Article↗
PubMed1993

Rearrangements of immunoglobulin and T-cell receptor genes in canine lymphoma/leukemia cells.

Tumor cells from 15 canine lymphoma/leukemia cases were examined for genetic rearrangements of immunoglobulin and T-cell receptor (TCR) genes in parallel with cell surface antigens. Ten of these 15 cases showed rearrangements of the immunoglobulin heavy chain (IgH) gene, while 4 cases displayed TCR beta-chain gene rearrangements on Southern blot analysis. All the cases with IgH gene rearrangements had multicentric form lymphoma, and 6 of the 10 cases were cell surface immunoglobulin-positive. On the other hand, the cases with TCR gene rearrangements included atypical lymphoma/leukemia cases, and 3 of the 4 cases were Thy-1 antigen-positive. Although the tumor cell lineage of a considerable number of lymphoma/leukemia cases could not be determined by phenotypic analysis, examination of the IgH and TCR gene rearrangements disclosed the lineages of 14 of 15 cases. Genetic analysis demonstrated that the tumor cells in most canine multicentric lymphomas were formed by clonal expansion of B-lymphocyte. These findings show that studies on the rearrangements of immunoglobulin and TCR genes are very useful for understanding the cellular origin, clonality and hierarchy of canine lymphoma/leukemia cells.

Animals↗
PubMed1993

Molecular cloning and chromosomal mapping of feline p53 tumor suppressor gene.

Alterations of the p53 tumor suppressor gene have been observed in a variety of human and mouse tumors. For investigation of the role of this gene in tumors in cats, feline p53 cDNA was molecularly cloned by PCR amplifications using primers based on the sequences conserved among several species. The cloned cDNA appeared to cover approximately 90% of the open reading frame of the feline p53 gene and had characteristic structures in common with the p53 genes of several other species. The amino acid sequence similarities of the feline p53 with the human, mouse, rat and chicken counterparts were 82.9%, 75.6%, 76.5% and 57.2% respectively. Moreover, using a panel of feline x rodent somatic cell hybrids, the feline p53 gene was assigned to feline chromosome E1. These data will be useful for determining the role of the p53 tumor suppressor gene in feline tumors.

Amino Acid Sequence↗
PubMed1993

Influence of Mn ion the action of dibutyryl cyclic AMP and forskolin on contraction, membrane response, and cyclic AMP-dependent protein kinase activity in rat myometrium.

Contractile response, membrane activity, and protein kinase A (PKA) activity were measured on the longitudinal muscle taken from the estrogen-treated rat uterus, and the influence of Mn ion on the inhibitory effects caused by db cAMP and forskolin was investigated. Phasic contractions generated in the muscle taken from the middle portion of uterus were depressed to 48 and 83% by 30 microM db cAMP and 0.1 microM forskolin in Mg-free Krebs solution, respectively; phasic contractions were more strongly depressed by the agents in the solution containing 0.2 mM Mn. Action potentials consisted of spike and plateau components, and the duration of the plateau potential was reduced by the application of the agents; membrane activity was more strongly depressed in the presence of 0.2 mM Mn. The contractile depression caused by db cAMP was reduced and by forskolin was enhanced by pretreatment of the tissue with 0.6 mM Mn for 30 min. The PKA activity was increased by 39 and 6% of the control, when 30 microM db cAMP and 0.1 microM forskolin were applied, respectively; the PKA activity in response to db cAMP and forskolin was reduced and enhanced, respectively, when the tissues were pretreated with 0.6 mM Mn. It was proposed that Mn ions permeated into cell interior when the muscle was exposed to 0.6 mM Mn, so that the effects of the agents were differently affected. It was also shown that plateau potential dominated in the muscle taken from the ovarian portion, and the contractile inhibition caused by the agents was far weaker.

Action Potentials↗
PubMed1993

Decrease of ischaemia-reperfusion related lung oedema by continuous ventilation and allopurinol in rat perfusion lung model.

Using isolated perfusion rat lung model, we studied the effect of continuous ventilation without perfusion and allopurinol on the development of ischaemia-reperfusion lung injury. Ischaemia was induced by stopping the perfusion. Normothermic ischaemia for 90 min without ventilation caused significant lung oedema. Continuous ventilation during ischaemia with 21% O2 decreased lung oedema significantly after 60 min of reperfusion. The same protection could be achieved by 100% N2 ventilation during 90 min of ischaemia, suggesting that xanthine oxidase (XO) is unlikely to cause the ischaemia-reperfusion lung injury. On the other hand allopurinol, XO inhibitor, equally inhibited lung oedema after 90 min of ischaemia and 60 min of reperfusion. These results indicate that mechanical movement of alveoli provides successful preservation of ischaemic lung, and allopurinol has some protective effect other than XO inhibition.

Allopurinol↗
PubMed1993

[The effect of fluticasone propionate topically dosed prior to the pollen scattering season on cellular infiltration into the surface of nasal mucous membrane in patients with Japanese cedar pollinosis].

In order to examine fluticasone propionate's mechanism of inhibiting nasal allergic symptoms, topical dosing of FP to patients with Japanese cedar pollinosis was started before the pollen scattering season, and the kinetics of basophilic cells and eosinophils which infiltrated into the surface of nasal mucous membrane were observed. Patients with Japanese cedar pollinosis were divided into two groups. Before and in the early period of the pollen scattering season, one group received FP and the other group a placebo, topically into the nostrils. In the mid and late season, both groups were treated with FP topical dosing. The study was carried out in the double blind manner. In the pre-, early and late season, specimens were scraped from the nasal mucosal surface, basophilic cell and eosinophil counts in the specimens were measured, and histamine and ECP contents in the specimens were also determined. Topical use of FP starting pre-season significantly inhibited symptoms of Japanese cedar pollinosis, as well as accumulation of basophilic cells and eosinophils in the nasal mucosal surface. Histamine and ECP contents in the nasal specimens tended to decrease with the topical use of FP.

Administration, Topical↗