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Biomedical subjects

M Okano

Publications and source records attributed to M Okano.

At least 145 records · Page 8Linked to original sources
PubMed1994

Retinoic acid up-regulates erythropoietin production in hepatoma cells and in vitamin A-depleted rats.

Retinoic acid (RA) stimulated the production of erythropoietin (Epo) in a human hepatoma cell line, HepG2 cells. The stimulation was due to the accumulation of Epo mRNA. The Epo production in HepG2 cells was also dependent on O2 tension for cell culture but the enhancement of Epo production by RA was independent of O2 tension, indicating that RA exerts its effect through a pathway different from O2. Oral administration of RA to the vitamin A-depleted rats elevated the concentration of Epo in serum. These results suggest that RA up-regulates EPO production in vivo as well as in vitro.

Animals↗
PubMed1994

A novel site of erythropoietin production. Oxygen-dependent production in cultured rat astrocytes.

It has been shown that neurons express erythropoietin (Epo) receptor, but the production of Epo protein in neural tissues has not been demonstrated. Cerebral cells of rat fetuses were cultured, and Epo in the spent medium was measured with an enzyme-linked immunoassay. Production of the immunoreactive Epo was dependent on O2 tension for cell culture; hypoxia enhanced the production. The immunoreactive Epo purified from the spent medium stimulated the growth of Epo-dependent myeloid cells and formation of fetal liver erythroid colonies. These biological activities were completely inhibited by the anti-Epo antiserum and the extracellular domain of the Epo receptor capable of binding with Epo. When brain Epo was compared with serum Epo, brain Epo was smaller in size and more active in vitro at low ligand concentrations. These differences appear to be caused by the different extent of sialylation. Analyses with the reverse transcription-polymerase chain reaction method indicated that the regulation of Epo production by oxygen operates at the level of its mRNA. Immunochemical staining of the immortalized clonal cells revealed that astrocytes produced brain Epo. These results provide a novel site of Epo production and suggest that Epo acts on neurons in a paracrine fashion.

Animals↗
PubMed1994

Immunohistochemical characterization of a stage-specific antigen during oogenesis and spermatogenesis recognized with monoclonal antibody.

In order to detect and characterize novel molecules which function in oogenesis, immunohistochemical study using a monoclonal antibody (MAb) raised against oocytes of Xenopus laevis was carried out. The distribution of the detectable molecule with MAb X-80, which specifically reacts with Xenopus previtellogenic oocytes; stages I and II (Dumont, 1972), in particular was analyzed. The hamster, mouse, chick, quail, Caenorhabditis elegans and Lilium longiflorum were also examined. Interestingly MAb X-80 bound not only in Xenopus oocytes but in its secondary spermatocytes and spermatids. Furthermore, MAb X-80 gave a similar staining pattern in the Lilium and other, although the stage when the positive reaction is detectable is different in the male and female germ cells.

Animals↗
PubMed1994

N-glycosylation of erythropoietin is critical for apical secretion by Madin-Darby canine kidney cells.

Erythropoietin (Epo) has three N-linked carbohydrate chains at positions 24, 38, and 83 in its 166-amino acid residues. When the human wild-type Epo was expressed in the polarized Madin-Darby canine kidney (MDCK) epithelial cells, Epo was preferentially secreted from the apical domain. The polarized secretion was perturbed by the treatment of the cells with tunicamycin, suggesting the involvement of N-linked carbohydrate chains in the apical sorting mechanism in MDCK cells. Replacement of asparagine residues at all N-glycosylation sites of Epo with glutamine by site-directed mutagenesis resulted in roughly equal secretion from apical and basolateral domains. Comparative studies on MDCK clones expressing the mutant Epos lacking one or two of the three N-glycosylation sites in every possible combination showed that the N-linked carbohydrate chain at position 38 is critical for the polarized secretion. Nocodazole, a microtubule-disrupting drug, reversed the polarized secretion of the wild-type Epo from the apical to basolateral preference with little change in the total secretion. Hepatocyte growth factor, a scatter factor known to induce the tubule-like structure of MDCK cells, caused almost equal secretion of the wild-type Epo into the apical and basolateral sides, although the tight junctions of MDCK cells remained intact.

Animals↗
PubMed1994

Extraocular muscle surgery in a rabbit model: site of reattachment following hang-back and conventional recession.

To determine the precise site of reattachment of recessed muscles, 4-mm conventional and hang-back recessions of the inferior rectus muscle were performed in 18 albino rabbits. Six weeks later, the distance from the anterior border of the reattached muscle to the insertion was measured both grossly and microscopically. In all cases the operated muscles had advanced minimally from the site of surgical placement. Gross observation showed that the mean forward creep was significantly greater for those rabbits which underwent hang-back recession (1.81 +/- 0.67 mm) than for those that were submitted to the conventional technique (0.83 +/- 0.38 mm). Measurements done on histological sections revealed that the mean distance of the anterior border of the muscle fiber from the reference suture was larger for conventional recession (2.73 +/- 0.75 mm) than for hang-back recession (1.91 +/- 0.72 mm).

Animals↗
PubMed1994

Bullous lymphoma of the skin.

We describe an extremely rare case of cutaneous B-cell lymphoma associated with bulla formation. The term, 'bullous lymphoma' is proposed for this variant of cutaneous lymphoma.

Aged↗
PubMed1994

Contact dermatitis due to budesonide: report of five cases and review of the Japanese literature.

BACKGROUND: Contact allergy to corticosteroids has recently gained increased attention. METHODS: Five cases of contact dermatitis due to budesonide, a nonhalogenated steroid, are described. The Japanese literature was reviewed for reports on this allergy, and the occurrence due to budesonide was compared with that of other dermocorticosteroids. RESULTS: Budesonide use can cause contact dermatitis. CONCLUSIONS: Although budesonide may be beneficial because of its anti-inflammatory effects, clinicians should be alert to its potential for causing contact dermatitis.

Administration, Topical↗
PubMed1994

Population analysis of cellular responses to synthetic peptides of Der p II, a major allergen molecule of Dermatophagoides pteronyssinus, in allergic and nonallergic subjects.

Responses of peripheral blood mononuclear cells to synthetic oligopeptides of Der p II, one of the major allergen molecules of Dermatophagoides pteronyssinus, were compared between allergic and nonallergic subjects. Healthy subjects showed positive responses to crude extracts of D. pteronyssinus, but only allergic subjects showed elevated cellular responses to Der p II. We synthesized three oligopeptides of Der p II in which motifs of a possible T-cell epitope were included. Of 14 subjects with positive response to Der p II, three responded to all three peptides, while five did not respond to any peptide tested. In 11 allergic patients who showed positive response to Der p II, responsiveness to the peptide K33-T47 was significantly higher than that to other peptides (P < 0.05). All the responding patients were also positive for scratch test to Der p II, suggesting that those epitopes induced IgE-promoting helper T-cell response in allergic persons. On the other hand, the in vitro cellular responses were not necessarily correlated to IgE production against Der p II in healthy subjects.

Adolescent↗
PubMed1994

Anaphylactoid purpura with intestinal perforation: report of a case and review of the Japanese literature.

A 78 year old man suffering from anaphylactoid purpura complained of abdominal pain and bloody stools. Combined therapy with Prednisolone and cyclophosphamide had been given against nephrotic syndrome caused by purpura nephritis. Severe abdominal pain with symptoms and signs of pan-peritonitis necessitated laparotomy. Rectosigmoid perforation due to necrotizing angiitis (phlebitis) was also demonstrated histologically. The patient died of septicemia 18 days after surgery. Perforation of the alimentary tract rarely occurs in anaphylactoid purpura. Twenty similar cases were briefly reviewed from the Japanese literature.

Aged↗
PubMed1994

Processing and secretion of Alzheimer's disease amyloid precursor protein.

We studied in vivo expression and in vitro secretion of the Alzheimer's disease amyloid precursor protein (APP). The results indicate that secretion of APP is mediated by PKC and the initial step of the processing may occur in the acidic secretory granules of the glial cells. Our results suggest that a metabolic switch of APP in neural cells is critical in amyloid deposition.

Alzheimer Disease↗
PubMed1994

Allergens of the house dust mite, Dermatophagoides pteronyssinus, in patients with mite allergic rhinitis: a clinical investigation by intracutaneous skin tests and nasal provocation tests.

To determine the allergens of mite allergic rhinitis, we studied 31 patients with mite allergic rhinitis by skin tests and nasal provocation tests (15 for skin and 16 for nasal tests) using 6 fractions of Dermatophagoides pteronyssinus (Dp) extract differing in molecular weights (15, 25, 32, 53, 95 and 190 kDMW). In skin testing, patients showed intense positive reactions to the fractions of 15, 25, 32, 95 and 190 kDMW, among which the most patients showed positive reactions to the fractions of 15 and 25 kDMW. Significant differences were found in patients' positive reactivity among each fraction and between low (15 and 25 kD) and high (95 and 190 kD) molecular weight fractions as well. In nasal provocation tests, patients showed intense positive reactions to the fractions of 15, 32, 53 and 95 kDMW, especially to the fractions of 15 and 95 kDMW. Furthermore, the insidence of positive reactions to the 15 kDMW fraction was significantly higher than that to any other fraction in the skin tests (P < 0.05). From these results, the low molecular weight fraction, 15 kDMW, is considered to be the main allergen of this mite and the high molecular weight fractions, 95 and 190 kDMW, may also be considered to be allergens of this mite.

Adolescent↗
PubMed1994

[Clinical characterization of allergic patients sensitized to Chamaecyparis obtusa--using AlaSTAT system].

Clinical characterization of patients with allergy to Chamaecyparis obtusa (Cypress) pollen and their specific IgE antibody was investigated by using AlaSTAT assay, a new method for measurement of antigen-specific IgE antibody. Positive rate of antigen-specific antibody in patients with allergic pollinosis was 83.5% for Japanese cedar pollen and 80.0% for Chamaecyparis obtusa pollen. 76.4% of patients were sensitized both to Japanese cedar and Chamaecyparis obtusa pollen, however, 7.9% were sensitized only to the latter. As for clinical symptoms, duration of attack was short and severity was mild or moderate in the patients sensitized only to Chamaecyparis obtusa pollen. Patients who visited hospital in April, in that Chamaecyparis obtusa pollen disseminated in the air predominantly, showed significant elevation in AlaSTAT scores compared with patients who visited in February and March (p < 0.05).

Adolescent↗
PubMed1994

Localization of ZP3 mRNA in mouse ovary by non-radioactive in situ hybridization with digoxigenin-labelled cDNA.

In situ hybridization using digoxigenin-labelled cDNA has dual advantages of having high structural resolution and high sensitivity and avoiding problems associated with the handling of radioactive materials. We have used this technique to detect and locate mRNA for mouse ZP3 protein in paraffin sections of fixed ovaries of newborn and adult mice. Mouse ZP3 mRNA was restricted to the cytoplasm of oocytes. After day 16, ZP3 mRNA expression was increasingly restricted to the cytoplasm of the oocyte. Previous work on the distribution of ZP3 mRNA was confirmed and we were able to show that using non-isotopic in situ hybridization, sensitive and accurate cellular localization was feasible in paraffin embedded mouse ovary.

Alkaline Phosphatase↗
PubMed1993

Distinct clonotypic Epstein-Barr virus-induced fatal lymphoproliferative disorder in a patient with Wiskott-Aldrich syndrome.

BACKGROUND: Recently, reports of Epstein-Barr virus (EBV)-induced lymphoproliferative disorders (LPD) have increased in number among immunosuppressed recipients of organ transplants. The importance of analyzing both the immunoglobulin gene and EBV termini is advocated for the investigation of pathogenetic mechanisms for clonal proliferation in EBV-induced LPD; however, the oncogenic mechanisms of EBV-induced LPD remain unclear. Furthermore, there are very few clonotypic studies of EBV-induced LPD in patients with primary immunodeficiency diseases. The authors studied the clonality of an EBV-induced fatal LPD in a 20-year-old patient with Wiskott-Aldrich syndrome (WAS), an X-linked recessive primary immunodeficiency disease. METHODS AND RESULTS: An autopsy showed non-Hodgkin lymphoma of B-cell origin with diffuse large cells in both systemic lymph nodes and extranodal organs. Immunohistochemical and Southern blot analyses showed polyclonal rearrangement of immunoglobulin genes in most of the lesions except for the pulmonary hilar lymph node. Furthermore, the analysis of restriction fragment length polymorphism with several fragments from EBV genome indicated that EBV genomes in all lesions were identical; however, a single but different-sized EBV termini was detected in every EBV-positive lesion when probed with the EcoRI-Dhet spanning terminal repeat region of EBV. CONCLUSIONS: The EBV-induced fatal LPD in a patient with WAS showed the characteristic clonotype, polyclonal immunoglobulin gene rearrangement, and monoclonal EBV terminal configuration. Furthermore, EBV termini in each lesion varied in size. This particular clonotype implicates several unique pathogenetic mechanisms for clonal proliferation of EBV-induced LPD.

Adult↗
PubMed1993

Eosinophil cationic protein in the nasal secretions of patients with mite allergic rhinitis.

In 25 patients with mite nasal allergy and 13 healthy control subjects, levels of eosinophil cationic protein (ECP) and histamine in nasal secretions were examined before and after challenge with mite extract. The ECP level was found to be significantly higher in the washings taken 30 minutes after challenge compared with the washings taken before challenge (P < .05). ECP levels measured both before and after mite extract challenge were found to be significantly higher in the patients than in the controls (P < .01). These facts suggest that the ECP affects the nasal mucosa by causing injury to ciliated cells and by acceleration of the processes of modification and inhibition of the allergic reaction.

Adolescent↗