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Biomedical subjects

H Tagami

Publications and source records attributed to H Tagami.

At least 37 records · Page 2Linked to original sources
PubMed1997

Construction of a contiguous 874-kb sequence of the Escherichia coli -K12 genome corresponding to 50.0-68.8 min on the linkage map and analysis of its sequence features.

The contiguous 874.423 base pair sequence corresponding to the 50.0-68.8 min region on the genetic map of the Escherichia coli K-12 (W3110) was constructed by the determination of DNA sequences in the 50.0-57.9 min region (360 kb) and two large (100 kb in all) and five short gaps in the 57.9-68.8 min region whose sequences had been registered in the DNA databases. We analyzed its sequence features and found that this region contained at least 894 potential open reading frames (ORFs), of which 346 (38.7%) were previously reported, 158 (17.7%) were homologous to other known genes, 232 (26.0%) were identical or similar to hypothetical genes registered in databases, and the remaining 158 (17.7%) showed no significant similarity to any other genes. A homology search of the ORFs also identified several new gene clusters. Those include two clusters of fimbrial genes, a gene cluster of three genes encoding homologues of the human long chain fatty acid degradation enzyme complex in the mitochondrial membrane, a cluster of at least nine genes involved in the utilization of ethanolamine, a cluster of the secondary set of 11 hyc genes participating in the formate hydrogenlyase reaction and a cluster of five genes coding for the homologues of degradation enzymes for aromatic hydrocarbons in Pseudomonas putida. We also noted a variety of novel genes, including two ORFs, which were homologous to the putative genes encoding xanthine dehydrogenase in the fly and a protein responsible for axonal guidance and outgrowth of the rat, mouse and nematode. An isoleucine tRNA gene, designated ileY, was also newly identified at 60.0 min.

Base Sequence↗
PubMed1997

Dendritic cells differently respond to haptens and irritants by their production of cytokines and expression of co-stimulatory molecules.

After application of haptens to the skin, Langerhans cells (LC), i.e. immature dendritic cells (DC) in the skin, move to secondary lymphoid organs to sensitize naive T cells. During this process, LC become mature DC with augmented expression of various co-stimulatory molecules and MHC class II antigens. In this scenario, however, critical questions remain as to what kind of chemicals can induce this maturation process through what kind of mechanisms. To clarify these questions, we used monocyte-derived CD1a+ DC instead of LC since LC maturated spontaneously in vitro culture. After we confirmed that monocyte-derived DC showed at least phenotypic characteristics and a response to TNF-alpha similar to LC, we added various chemicals, i.e., dinitrochlorobenzene (DNCB), trinitrochlorobenzene (TNCB), NiCl2, ZnCl2, sodium dodecyl sulfate (SDS), or benzalkonium chloride (BC), to a culture of purified monocyte-derived CD1a+ DC. Of these chemicals, only NiCl2 and DNCB significantly increased the surface expression of CD54, CD86, HLA-DR antigen, and interleukin (IL)-1 beta production, while SDS, BC, or ZnCl2 could not augment them, except for weak augmentation of CD86 expression by SDS. The increase in the expression of CD86 induced by NiCl2 or DNCB was most remarkable, being observed in DC from almost all the subjects we examined. TNCB could also induce responses similar to those induced with DNCB, but the number of subjects whose DC responded to it was far less than that of subjects whose DC responded to NiCl2 or DNCB. In spite of the augmented CD86 expression on DC treated with DNCB or NiCl2, these chemicals induced different responses of DC in their expression of CD54 and HLA-DR and the production of IL-6 and tumor necrosis factor (TNF)-alpha. In addition, the up-regulation of CD86 expression on DC treated with DNCB was significantly suppressed by either anti-IL-1 beta or anti-TNF-alpha antibody, while that by NiCl2 was relatively insensitive to these antibody treatments. Finally, the protein kinase C inhibitor, H7, but not staurosporine, could suppress the augmentation of CD86 expression on DC induced either by NiCl2 or by DNCB. These data suggest that DC respond to some haptens by changing their expression of several co-stimulatory molecules and their production of cytokines with a resultant change in antigen-presenting function. They also suggest that these chemicals stimulate DC by different mechanisms. By these responses, DC may modulate the final immune response to chemicals.

Antibodies↗
PubMed1997

Dehydroepiandrosterone may be one of the regulators of cytokine production in atopic dermatitis.

Previous studies in mice have shown that dehydroepiandrosterone (DHEA) increases the production of Th1-associated lymphokines, and of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma), by lymphocytes. However, there are no reports concerning the effect of DHEA on the production of Th2-associated lymphokines, IL-4 and IL-5, by lymphocytes in humans. We examined serum DHEA levels in patients with atopic dermatitis (AD), which is thought to be associated with a higher activity of Th2 cells than of Th1 cells. We also studied the effects of DHEA on the production of IL-4 and IL-5 by human lymphocytes. Serum DHEA concentrations in 47 adult male patients with AD aged 19-30 years were significantly lower than those of 53 age-matched healthy male controls. Preincubation of peripheral blood mononuclear cells (PBMCs) with DHEA reduced the IL-4 production by concanavalin A-stimulated PBMCs. Their IL-5 production also showed a tendency to decrease. These results suggest that DHEA may be one of the regulators of IgE synthesis and eosinophil proliferation in patients with AD and it may act by controlling IL-4, IL-5 and IL-2 production by lymphocytes.

Adult↗
PubMed1997

C3 production of cultured human epidermal keratinocytes is enhanced by IFNgamma and TNFalpha through different pathways.

We investigated the regulation of C3 production by human cultured epidermal keratinocytes by enzyme-linked immunosorbent assay. The results showed that IFNgamma and TNFalpha enhanced the synthesis of C3 by epidermal keratinocytes in a concentration-dependent manner. Moreover, a protein kinase C (PKC) inhibitor blocked C3 production, whereas PMA enhanced it. There was a synergistic effect between IFNgamma and TNFalpha. In experiments to investigate the role of protein tyrosine kinase (PTK) in C3 production, we found that treatment with herbimycin A, a specific inhibitor for the c-Src-related PTK, caused significant enhancement of the C3 production induced by IFNgamma or TNFalpha, suggesting that c-Src-type PTK(s) provides a negative signal to C3 production. Each competitive inhibitor of PTK, genistein or tyrphostin, substantially increased the C3 production by IFNgamma at lower concentrations, although each agent had little effect on TNFalpha-associated production of C3 at the same concentrations. The data show that pro-inflammatory cytokines IFNgamma and TNFalpha synergistically augment C3 production by epidermal keratinocytes by different pathways.

Cells, Cultured↗
PubMed1997

Exercise-induced urticaria and angioedema: reports of two cases.

Two Japanese patients presented with histories of exercise-induced urticaria and facial angioedema, respectively. Each patient exercised by climbing steep stairs for 5 to 10 min at 22 degrees C. A 19-year-old female student with atopic dermatitis initially developed lesions of cholinergic urticaria, which became confluent on her face, trunk and extremities and were followed by discomfort of her throat. In a 34-year-old female patient, the exercise induced angioedema on the right eyelids preceded by sneezing and rhinorrhea. Plasma histamine levels were elevated in the first patient. No changes in serum levels of complement systems were observed after the exercise challenge in either patient.

Adult↗
PubMed1997

Inverse correlation between CD34 expression and proline-4-hydroxylase immunoreactivity on spindle cells noted in hypertrophic scars and keloids.

The CD34 positive (CD34+) spindle cells constitute a special population of spindle cells which shows a unique distribution in the skin. So far, however, the functional role of CD34+ spindle cells and the regulation of CD34 expression on dermal spindle cells are totally unknown. We examined immunohistologically the pattern of the expression of CD34 and proline-4-hydroxylase, a marker for the fibroblasts that participate in active collagen synthesis, on dermal spindle cells at various stages of scar and keloidal tissues. Dermal spindle cells in the lesions of hypertrophic scar and those at inflammatory expanding borders of keloids totally lost CD34 expression, but they strongly expressed proline-4-hydroxylase. On the other hand, they expressed CD34, together with decreased immunoreactivity to anti-proline-4-hydroxylase antibody, in non-inflammatory scars or in a non-inflammatory central portion of keloid. In two cases of scars, in which inflammation began to subside, double immunofluorescence demonstrated that both CD 34 and proline-4-hydroxylase were expressed on the same spindle cells. CD34 expression, once disappeared from the lesions of hypertrophic scar or keloid, seems to return on CD34-proline-4-hydroxylase+ cells, when the initial inflammatory changes begin to regress. There is a reverse correlation between CD34 expression on spindle cells and the synthesis of type I collagen in the skin.

Adolescent↗
PubMed1997

Sweet's syndrome in acute myelogenous leukemia showing dermal infiltration of leukemic cells.

We encountered a 76-year-old woman with acute myelogenous leukemia (AML) who developed Sweet's syndrome. A biopsy specimen taken from her skin lesion on the upper arm showed an infiltration of numerous neutrophils intermingled with leukemic cells. As far as we know, this is the first report of Sweet's syndrome showing a phenotypically identified leukemic cell infiltration of AML determined as M2 in the French-American-British classification.

Aged↗
PubMed1997

Keratoacanthoma developing in prurigo nodularis treated with cryotherapy.

We describe an elderly woman in whom keratoacanthoma developed from one nodule of prurigo nodularis that had been treated with cryotherapy for 3 months. Since in our case keratoacanthoma developed after treatment with liquid nitrogen for prurigo nodularis which had been constantly scratched in the past, we hypothesize that irritations of cryotherapy in addition to repeated mechanical traumas of scratching might have played a role in the formation of this tumor.

Aged↗
PubMed1997

Metaplastic bone formation in the subcutaneous nodule of a patient with mixed connective tissue disease.

Cutaneous ossification is a rare phenomenon in collagen diseases, despite the rather frequent occurrence in these diseases of dystrophic calcinosis. We observed metaplastic woven bone formation associated with calcification in biopsy material obtained from a 49-year-old woman suffering from mixed connective tissue disease together with multiple subcutaneous indurations. This is the first case of the presence of metaplastic bone formation in a patient with mixed connective tissue disease.

Female↗
PubMed1997

Comparison of immune reactivity profiles against various environmental allergens between adult patients with atopic dermatitis and patients with allergic respiratory diseases.

To clarify the pathomechanisms underlying the involvement of different organs by atopic dermatitis (AD) and allergic respiratory disease (ARD), we compared the immune reactivities to various environmental allergens between 46 adult patients who suffered only from AD but were without any history of ARD and 41 patients who had only ARD, using a RAST FEIA (radioallergosorbent test/fluoroenzyme immunoassay) and a scarification patch test. We also studied 42 healthy adult subjects in a similar fashion. Total serum IgE antibody levels were found to be far higher in the AD group than in the ARD and healthy control group, and RAST revealed that the AD group was sensitized to far larger numbers of allergens such as food mix, cereal mix, fungus mix and Candida albicans than were the other groups. The ARD group displayed a high incidence in RAST, comparable to that of the AD group, only against Japanese cedar and grass pollen mix antigen. However, the most remarkable difference in the immune reactivity profiles was that the AD group showed a uniquely higher RAST score and a lower incidence of positive patch test reactions to C. albicans antigen than did the ARD group. The reactivities in the ARD group to C. albicans antigen did not differ from those in the control group. Our present data suggest that a more pronounced shift from Th1 to Th2 cells, reactive against various allergens, takes place in AD patients.

Adolescent↗
PubMed1997

Non-pigmented nodular plantar melanoma in 12 Japanese patients.

In the Japanese, melanoma most commonly involves the plantar surface. Among 61 patients with plantar melanoma, we diagnosed 50 patients as acral lentiginous melanoma (ALM), nine as nodular melanoma, and two as superficial spreading melanoma. Partial or complete loss of pigment was observed in four of the nine nodular melanoma cases and in the nodular portions of eight ALM cases. All 12 such nodular lesions were ulcerated. The clinical diagnosis of malignant melanoma was easily made in the eight patients with ALM by the characteristic pigmentary changes around the nodule. The presence of some remaining pigment was found to be helpful in making the diagnosis in two lesions of nodular melanoma which, at first, had been clinically diagnosed as eccrine poromas. One of two completely amelanotic nodular melanomas was strongly suspected to be a melanoma because there was a history of a pre-existing pigmented macule before the development of the nodule. The other one required histopathological differentiation from Merkel cell carcinoma. Based on these findings and compared with melanoma on other parts of the body, pigmentation noted in the ulcerative nodule of plantar melanoma seems to disappear easily. This causes difficulty in distinguishing it from other skin tumours.

Aged↗