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Biomedical subjects

H Akama

Publications and source records attributed to H Akama.

At least 73 records · Page 4Linked to original sources
PubMed1990

Mononuclear cells enhance prostaglandin E2 production of polymorphonuclear leukocytes via tumor necrosis factor alpha.

To clarify the interactions between mononuclear cells and polymorphonuclear leukocytes, and to identify the cytokine(s) that mediate the interaction, the effects of a culture supernatant of LPS-stimulated mononuclear cells on production of arachidonic acid metabolites of polymorphonuclear cells were studied. The culture supernatant of LPS-stimulated mononuclear cells increased production of prostaglandin E2 of polymorphonuclear cells. TNF alpha, but not IL-1, IL-2, IL-6, or IFN gamma, enhanced the prostaglandin E2 production when added in vitro. Additionally, an anti-rTNF alpha monoclonal antibody inhibited the stimulating activity of the culture supernatants. TNF alpha, produced by mononuclear cells, appears to play an important role in the development of inflammation, such as rheumatoid arthritis, by enhancing the arachidonic acid metabolism of the polymorphonuclear cells.

Adult↗
PubMed1990

Primary adrenocortical micronodular dysplasia: enzyme histochemical and ultrastructural studies of two cases with a review of the literature.

The adrenal glands from two patients with primary adrenocortical micronodular dysplasia (PAMD) were studied (no. 1, a 23-year-old man with cardiac myxomas and sarcoidosis; no. 2, a 16-year-old girl). The PAMD cells showed intense activity of 3 beta-hydroxysteroid dehydrogenase (3 beta DH), succinate DH, glucose-6-phosphate DH, alkaline phosphatase (AlPase), and other DHs and lysosomal hydrolases, giving a characteristic staining pattern. The staining patterns correlated well with ultrastructural findings. The larger adrenals (no. 1: 16.6 g) were associated with larger black nodules and internodular cortex (INC) with fairly well-retained enzyme activities, and contained cell clusters and single cells with intense AlPase activity with the appearance of PAMD nodules in the buds. The smaller adrenals (no. 2: 5.4 g) were associated with smaller black/yellow nodules, and had INC with weaker enzyme activity. Analysis of descriptions of INC in 25 previously reported cases revealed that the larger adrenals (more than 10 g) had less atrophic INC than the smaller ones. The characteristic enzyme pattern in PAMD cells explains the paradox that PAMD adrenals smaller than normal can cause Cushing's syndrome, and may be useful for investigating neoplastic and non-neoplastic counterparts in other adrenal lesions. The relationship between PAMD cells and INC is not simply one of autonomy versus atrophy, and both cell types may be stimulated by a certain common trophic factor. Thus, PAMD belongs to the category of hyperplasia.

3-Hydroxysteroid Dehydrogenases↗
PubMed1990

[Low dose methotrexate therapy in rheumatoid arthritis].

Twenty-three patients were included in this prospective study about the safety and efficacy of oral low dose methotrexate (MTX) in the treatment of refractory rheumatoid arthritis. Patients received a mean dosage of 6.6 +/- 1.8 (SD) mg weekly over a mean duration of 16.6 +/- 12.5 months. Patients improved significantly in all clinical parameters of efficacy. There were significant reductions in Lansbury joint scores (p less than 0.001), duration of morning stiffness (p less than 0.001), sedimentation rates (p less than 0.001), C-reactive protein (p less than 0.01), IgG(p less than 0.01), rheumatoid factor (p less than 0.01) and significant increase in grip strength (p less than 0.001), hemoglobin (p less than 0.05) after 17 months of treatment with MTX. Radiographic progression of joint disease were assessed using global scoring method. The mean rate of development of erosions and joint-space narrowing during MTX therapy was significantly less than the rate of radiographic progression before MTX therapy (8.1 +/- 7. 9/year vs. 1.9 +/- 3.8; p less than 0.05). Adverse reactions during MTX therapy included transient transaminase elevation (17.4%). Five patients (21.7%) were withdrawn because of leukopenia (2), interstitial pneumonitis (1), stomatitis (1), skin rash (1). We conclude that low-dose methotrexate is effective for the management of clinical disease activity in patients with refractory rheumatoid arthritis and may be a disease-modifying anti-rheumatic drugs (DMAR-Ds) by roentgenographic criteria.

Adult↗
PubMed1989

In vivo responsiveness to glucocorticoid correlated with glucocorticoid receptor content in peripheral blood leukocytes in normal humans.

Dexamethasone loading tests (0.1 mg dexamethasone/kg, iv) were performed in 18 normal males to evaluate the individual responsiveness to glucocorticoid. There were inter-individual differences in increase in peripheral blood polymorphonuclear leukocyte count, decrease in peripheral blood lymphocyte count, and increase in plasma free fatty acids levels after dexamethasone injection. In addition, there was a significant correlation between the maximum increase in polymorphonuclear leukocytes and the maximum decrease in lymphocytes (r = 0.7514, p less than 0.0003). Simultaneous measurements of glucocorticoid receptor content by whole-cell assay revealed that glucocorticoid receptor content in polymorphonuclear leukocytes linearly correlated with that in the corresponding lymphocytes (r = 0.9482, p less than 0.0001). There were also significant correlations between the maximum increase in polymorphonuclear leukocytes and glucocorticoid receptor content in polymorphonuclear leukocytes (r = 0.7239, p less than 0.0007), and between the maximum decrease in lymphocytes and glucocorticoid receptor content in lymphocytes (r = 0.7703, p less than 0.0002). These results suggest that individual differences are preserved both in glucocorticoid responsiveness and in glucocorticoid receptor content in peripheral blood leukocytes in normal humans.

Adolescent↗