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Biomedical subjects

S Imamura

Publications and source records attributed to S Imamura.

At least 325 records · Page 18Linked to original sources
PubMed1989

Evaluation of ATPase-positive Langerhans' cells in skin lesions of lupus erythematosus and experimentally induced inflammations.

We examined the time-dependent dynamics of epidermal Langerhans' cells (LC) in human systemic lupus erythematosus (SLE), in MRL/Mp-lpr/lpr(MRL/lpr) mice, and in various experimental cutaneous inflammations, such as the Arthus reaction, dinitrochlorobenzene allergic dermatitis, and croton oil primary irritant dermatitis, in order to clarify the pathomechanisms of lupus skin lesions. The numbers of LC in untreated SLE patients with newly developed skin lesions decreased in the central lesional sites and increased significantly in the peripheral lesional sites. In MRL/lpr mice, the number of LC increased significantly in the central lesional sites during the initial stage and increased in the peripheral lesional sites and decreased in the central lesional sites 2-4 weeks after the onset of skin lesions. In contrast, with experimental cutaneous inflammations of guinea pigs, the increase in numbers of LC in the peripheral lesional sites was not significant during the time course of the reaction. These results suggest that the increased numbers of LC during the active and early stages of skin lesions in human SLE and MRL/lpr mice are closely related to the specific spontaneous development of skin lesions, unlike the dynamics of LC in experimental cutaneous inflammations.

Adenosine Triphosphatases↗
PubMed1989

Regressing ulcerative histiocytosis.

A 15-year-old girl presented with many round to oval erythematous indurated plaques on the trunk, scalp, and proximal portion of the extremities. The individual lesions showed ulceration within a short period but spontaneously healed after 2 or 3 months. The main histological feature was dermal proliferation of rather mature histiocytes that were regarded as neither inflammatory nor neoplastic, with subsequent destruction of normal dermal tissue architectures. Lymph nodes, bone marrow, and internal organs were not involved. The lesions were improved neither by potassium iodide therapy nor by combined therapy of corticosteroid and cyclophosphamide, but the patient recovered by clofazimine after a 2-year course. We considered this case to be an unusual form of cutaneous histiocytic proliferation, which we tentatively termed "regressing ulcerative histiocytosis."

Adolescent↗
PubMed1989

Reduced superoxide dismutase activity in xeroderma pigmentosum fibroblasts.

This study was performed in order to assess the possible protective effect of superoxide dismutase (SOD) on ultraviolet (UV) damage in xeroderma pigmentosum (XP) fibroblasts. SOD activity in fibroblasts originating from seven xeroderma pigmentosum (XP) patients was significantly lower than that in normal cells (p less than 0.005). Average SOD activity in XP cells belonging to complementation group A was 3.68 +/- 0.54 (n = 7) and that in normal human cells was 5.79 +/- 1.59 (n = 6). Addition of SOD before and during UV irradiation (UVB and UVC) to the cells caused no change in the amount of unscheduled DNA synthesis and UV survival. A possible involvement of reduced SOD in XP and a possible protective effect by SOD on UV damage is discussed.

Adolescent↗
PubMed1989

Southern blot analysis of clonal rearrangements of T-cell receptor gene in plaque lesion of mycosis fungoides.

T-cell populations of 22 plaque lesions from seven mycosis fungoides patients were studied for clonal rearrangement of the beta chain of the T-cell receptor (T beta) gene. All plaque lesions employed in this study showed clinically similar appearance. Histologically, all the biopsy specimens showed epidermotropism and the dermal infiltration of mononuclear cells including atypical cells. Histochemically, the majority of the infiltrated cells had surface markers of helper T cells. DNA extracted from skin lesions, peripheral lymphocytes, and lymph nodes revealed that the monoclonal expansion of T cells was different among patients and lesions. DNA extracted from the two skin lesions of case 1 revealed a clonal expansion of T cells. The rearranged bands persisted for about 1 year. In contrast, all lesions from cases 3-7 showed no rearranged band. Interestingly, three lesions from case 2 showed mixed type results, i.e., the monoclonal expansion of T cells was detected in one lesion but not in the other two lesions. Time course study of case 2 revealed that the same rearranged band became detectable in all three skin lesions and a lymph node about 1 year later. These results suggest that in plaque lesions of mycosis fungoides, there are various stages of detectable monoclonality of infiltrating cells, although the clinical appearance of the plaques was similar, and that the variety of monoclonality may reflect the long clinical course of this disease.

Blotting, Southern↗
PubMed1989

Effects of 1 alpha,25-dihydroxyvitamin D3 on the transglutaminase activity of transformed mouse epidermal cells in culture.

Induction of the transglutaminase activity of a transformed mouse epidermal cell line (PAM 212 cells) by 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25-(OH)2-D3), the active form of vitamin D3, was investigated. Addition of 1 alpha,25-(OH)2-D3 to a culture medium stimulated twice the transglutaminase activity at a concentration of 10(-7) M, but vitamin D3, prostaglandin E1, E2, and F2 alpha failed to show this induction. Phorbol 12-o-tetradecanoylphorbol-13-acetate (TPA) and dexamethasone also induced an increase in transglutaminase activity. Exposure to both 1 alpha,25-(OH)2-D3 and retinoic acid caused remarkably synergistic effects on the induction of transglutaminase in the PAM 212 cells. In contrast, simultaneous addition of 1 alpha,25-(OH)2-D3 and TPA was antagonistic and resulted in less than additive induction. Vitamin D3 also showed a similar but lesser effect. These results suggest that 1 alpha,25-(OH)2-D3 induces the transglutaminase activity via mechanisms disparate from those of retinoic acid and modifies epidermal differentiation.

Animals↗
PubMed1989

Analysis of epidermal growth factor receptor gene in psoriasis.

Epidermal Growth Factor (EGF) plays an important role in cell proliferation. In psoriasis, increased histochemical expression of EGF receptor has been reported in the epidermis. In order to elucidate the mechanism of this increase, we studied the EGF receptor gene organization in psoriasis. DNAs were extracted from white blood cells of 5 patients with psoriasis and 5 normal controls and also from epidermis of 2 psoriatic patients and 1 normal control, and analyzed by Southern blot technique. There were no differences in the structural organization of EGF receptor gene in either white blood cells or epidermis between psoriatic patients and normal controls. These results suggest that the histochemical increase of EGF receptor in the epidermis of psoriatic patients is not due to a structural change in this gene.

Blotting, Southern↗
PubMed1989

Suppression of contact sensitivity by local hyperthermia treatment due to reduced Langerhans cell population in mice.

The effects of local hyperthermia treatment on contact sensitivity (CS) and on the number of Langerhans cells (LCs) were studied in mice. CS was significantly suppressed when mice were sensitized in the hyperthermia treated skin I, 2 or 4 days after treatment (43 degrees C for 45 min). This suppressive effect was not observed 7 or 14 days after the treatment. CS was also suppressed when mice were sensitized in non-treated skin I day after the treatment. The density of LCs detected as ATPase-positive cells also decreased significantly 1, 2, 4 and 7 days after the treatment. There appeared to be a positive correlation between the number of LCs and the extent of CS when mice were sensitized at hyperthermia treated skin. It was observed that this suppressive effect on CS was dose- and temperature-dependent. It could be transferred by spleen cells from the hyperthermia treated and DNFB-sensitized donors, and was antigen specific when spleen cells were transferred before sensitization of the recipient mice. This indicated it was, in part, associated with the induction of suppressor cells. These findings suggest that local hyperthermia treatment reduces the number of LCs with subsequent suppression of the induction phase of delayed-type hypersensitivity by the generation of antigen-specific suppressor cells.

Animals↗
PubMed1989

Lymphomatoid papulosis: ultrastructural, immunohistochemical and gene analytical studies.

Ultrastructural, immunohistochemical and gene analytical studies were carried out on a 39-year-old patient with lymphomatoid papulosis. Two different cell groups were demonstrated in the papulonodular eruptions: large atypical cells with multiple nuclei that were well stained with anti-Tac, but not with Leu 3a, and other cells that possessed prominent hyperchromatic nuclei and which stained well with Leu I and Leu 3a but not with anti-Tac. Gene analytical studies using EcoRI, BamHI and HindIII revealed no rearrangement, indicating a non-clonal T-cell proliferation unlike malignant T-cell lymphoma. These results suggest that the present case was benign.

Adult↗
PubMed1989

Late onset erythropoietic porphyria.

A 51-year-old Japanese man and his 56-year-old sister of consanguineous parents had skin lesions with areas of dark-brown pigmentation and blisters with minimal trauma on sun-exposed skin which resembled those seen in porphyria cutanea tarda. Their fresh urine was wine-red in colour and fluoresced with ultraviolet light. The peripheral blood contained fluorocytes and porphyrin analysis of the red blood cells, urine and faeces of the patients revealed an increase of the isotype I of uro- and coproporphyrin and normal concentrations of delta-aminolaevulinate and porphobilinogen, suggesting the diagnosis of erythropoietic porphyria. No other members of this family had symptoms or biochemical findings suggestive of porphyria. We consider these two cases to be that of late onset erythropoietic porphyria.

Erythropoiesis↗
PubMed1989

Glucose-induced insulin secretion from perifused isolated islets in rats.

Glucose-induced insulin secretion in rat pancreas islets was studied by means of the modified perifusion technique. The biphasic insulin increase after 0.3% glucose application consisted of a rapid response (the first phase response) and a delayed one (the second phase response). The former was brought about by shortening the 0.3% glucose application time to one and a half minutes and the latter by treatment with 1 microgram/ml of synthetic somatostatin. It was proposed that the rapid response depended mainly on D-cell activity and the delayed response depended on B-cell function.

Animals↗
PubMed1989

[Massive pericardial effusion in a patient with scleroderma with special reference to concentration of alpha-hANP in plasma and pericardial effusion].

A 41-year-old woman was admitted to our hospital because of scleroderma and combined valvular disease (mitral stenosis, aortic regurgitation, tricuspid regurgitation) associated with massive pericardial effusion. Plasma atrial natriuretic peptide (alpha-hANP) level was 130 pg/ml on admission, and increased temporarily with a decrease of pericardial effusion, without significant of changes of pulmonary capillary wedge pressure, pulmonary arterial pressure, right ventricular pressure nor right atrial pressure. These findings suggest that one of the mechanisms of alpha-hANP secretion, a stretch receptor mechanism, is interfered by the massive pericardial effusion. There was no relationship between atrial pressures and plasma alpha-hANP levels in this case. alpha-hANP concentration in pericardial effusion (486 pg/ml) was four to five folds higher than the plasma alpha-hANP levels.

Adult↗
PubMed1989

[Pathogenesis of pulmonary involvement in HTLV-I-associated myelopathy (HAM): studies on T-cell function].

It has been shown that there are pulmonary involvements in patients with HTLV-1-associated myelopathy (HAM). Pulmonary lesions found in HAM are characterized by T-lymphocytosis and increased levels of soluble IL-2 receptor in bronchoalveolar lavage fluid. Peripheral blood lymphocytes from HAM patients proliferated spontaneously when cultured in vitro. Lymphocytes proliferated were positive for CD3 and HLA-DR staining. There were CD4+ cells and CD8+ cells in proliferating T-lymphocytes 5 days after cultivation. Culture supernatants of proliferating cells showed an increased soluble IL-2 receptor. These results suggest that activated T-cells play an important role in developing pulmonary lesions in HAM.

Adult↗