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Biomedical subjects

H Tagami

Publications and source records attributed to H Tagami.

At least 145 records · Page 8Linked to original sources
PubMed1995

Different expression of E-cadherin by two cutaneous gamma/delta TcR+ T-cell subsets, V gamma 5- and V gamma 5+ gamma/delta TcR+ T cells.

Recently we have demonstrated that, besides V gamma 5+ gamma/delta TcR+ T cells (V gamma 5+ gamma/delta T cells), V gamma 5- gamma/delta TcR+ T cells (V gamma 5- gamma/delta T cells) are also present in murine skin. In the present study, to characterize the functional differences between these two different cutaneous gamma/delta T cells we examined the expression pattern of E-cadherin and its two integrins. After co-culturing of Ly-5+ epidermal cells and migrating cells from organ-cultured murine skin with cutaneous stromal cells, we could expand V gamma 5+ gamma/delta T cells and V gamma 5- gamma/delta T cells, respectively. Flow cytometry demonstrated that cultured V gamma 5+ gamma/delta T cells expressed E-cadherin, but V gamma 5- gamma/delta T cells did not. This difference in E-cadherin expression was also observed in freshly isolated V gamma 5+ and V gamma 5- gamma/delta T cells. On the other hand, both V gamma 5+ and V gamma 5- gamma/delta T cells expressed the alpha chain of the vitronectin receptor, but did not express the alpha 4 integrin. Of these two cutaneous gamma/delta T cells, only V gamma 5+ gamma/delta T cells adhered to murine keratinocyte cell line, PAM 212 cells. Unexpectedly, however, the adhesion of E-cadherin-expressing V gamma 5+ gamma/delta T cells to PAM 212 cells was not inhibited by anti-E-cadherin antibody, which effectively abrogated the adhesion of Langerhans cells to PAM 212 cells. These distinct phenotypic and functional characteristics in the sub-sets of cutaneous gamma/delta T cells may suggest that they reside in different locations in the skin to play different functional roles in skin immunophysiology.

Animals↗
PubMed1995

Mechanism of human polymorphonuclear leukocyte adhesion to serum-treated corneocytes.

The accumulation of polymorphonuclear leukocytes (PMN) beneath the stratum corneum is a characteristic histopathologic finding in various aseptic pustular dermatoses. To elucidate the pathomechanism involved in this phenomenon, we investigated whether PMN also attach to a sheet of corneocytes in vitro. A 1-cm2 corneocyte sheet was attached to a sterile glass slide with double adhesive tape used for skin graft surgery before incubating with human serum. The PMN suspension then was applied to the sheet. Attached cells were stained with May-Grunwald-Giemsa and counted with a computer image analyzer. We quantitatively assessed PMN adhesion to the serum-treated corneocyte sheets, which was mediated by activation of the alternative complement pathway. Addition of either anti-CD18 or anti-CD11b antibody to the assay system resulted in a marked reduction of PMN adhesion. We also demonstrated immunohistochemically that iC3b was formed on the serum-treated corneocytes. These findings suggest that PMN attach to serum-treated corneocytes through an interaction of CR3 expressed on PMN with iC3b-coated corneocytes. In addition, we found that this adhesion was enhanced by activation of PMN with phorbol myristate acetate. From these results, we speculate that complement activation by corneocytes occurs in the cutaneous lesions of aseptic pustular dermatoses and that PMN can be stimulated by the interaction with iC3b-opsonized corneocytes as well as by chemotaxins, leading to damage of the surrounding epidermal keratinocytes.

Blood Physiological Phenomena↗
PubMed1995

Nodular melanoma in 62 Japanese patients: influence of initial surgical treatment on local recurrence and prognosis.

The incidence of malignant melanoma is much lower in Japanese than in Caucasians, and the commonest type of melanoma in Japanese is acral lentiginous melanoma (ALM). In contrast to the improved prognosis noted in ALM, it is now of increasing concern that there is a rise in both the frequency and mortality of nodular melanoma. During the 25 years from 1970 to 1994, we observed 190 patients with melanoma, including 62 nodular melanomas and 96 ALM, at the Department of Dermatology, Tohoku University Hospital, Sendai, Japan. We retrospectively reviewed the recurrence and survival rates of nodular melanoma observed. The proportion of nodular melanoma, once comprising only 24% of all melanomas, showed a sharp increase to 40% after 1982. The anatomical sites of the primary tumor were the hands and feet (29%), extremities excluding hands and feet (27%), head and neck (23%), and trunk (21%). Comparison of the stages of nodular melanoma when diagnosed showed that the proportion of stage III remained highest throughout the whole period, but that of stage II melanomas increased after 1982. After treatment, local recurrence occurred far more frequently in nodular melanoma (19%) than in ALM (1%). The prognosis of nodular melanoma was also less favorable than that of ALM, although it slightly improved after 1982; the 5-year survival rates before and after 1982 were 34 and 50%, respectively. Twenty-eight patients with nodular melanoma had underwent simple excision or incisional biopsy of the primary tumor at another institution and were later referred to us for further intensive care or for the treatment of local recurrence and/or metastases.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined Modality Therapy↗
PubMed1995

Acrokeratosis paraneoplastica (Bazex syndrome) associated with primary cutaneous squamous cell carcinoma of the lower leg, vitiligo and alopecia areata.

We report a case of acrokeratosis paraneoplastica (AP; Bazex syndrome), characterized by typical palmoplantar hyperkeratosis and psoriasiform scaly erythema of the acral regions, associated with primary cutaneous squamous cell carcinoma (SCC) on the left lower leg. This 54-year-old Japanese man subsequently developed vitiligo, and alopecia areata of the scalp. Serial monitoring of squamous cell carcinoma antigen (SCC-Ag) demonstrated that the severity of the clinical manifestations of AP paralleled the serum concentrations of SCC-Ag. We suggest that an immune-mediated mechanism underlies the development of AP in this patient.

Alopecia Areata↗
PubMed1995

Glucose lowers CRP* levels resulting in repression of the lac operon in cells lacking cAMP.

CRP-cAMP-dependent operons of Escherichia coli can be expressed in cells lacking functional adenylate cyclase when they carry a second-site mutation in the crp gene (crp*). It is known that the expression of these operons is repressed by glucose, but the molecular mechanism underlying this cAMP-independent catabolite repression has been a long-standing mystery. Here we address the question of how glucose inhibits the expression of beta-galactosidase in the absence of cAMP. We have isolated several mutations in the crp gene that confer a CRP* phenotype. The expression of beta-galactosidase is reduced by glucose in cells carrying these mutations. Using Western blotting and/or SDS-PAGE analysis, we demonstrate that glucose lowers the cellular concentration of CRP* through a reduction in crp* mRNA levels. The level of CRP* protein correlates with beta-galactosidase activity. When the crp promoter is replaced with the bla promoter, the inhibitory effect of glucose on crp* expression is virtually abolished. These data strongly suggest that the lowered level of CRP* caused by glucose mediates catabolite repression in cya- crp* cells and that the autoregulatory circuit of the crp gene is involved in the down-regulation of CRP* expression by glucose.

Adenylyl Cyclases↗
PubMed1995

Ichthyosiform eruption in a patient with Dubowitz syndrome.

Dubowitz syndrome is a rare autosomal recessive disorder characterized by intrauterine and postnatal growth retardation, microcephaly, moderate mental retardation, typical craniofacial anomalies, and eczematous skin lesions. We report a case of Dubowitz syndrome associated with ichthyosiform skin changes.

Child, Preschool↗
PubMed1995

Detection of point mutations in human tyrosinase gene by improved allele-specific amplification.

Allele-specific amplification (ASA) is a simple and non-radioactive technique for detecting known point mutations that produce genetic diseases. Although this technique is based on the specific amplification of the target allele by a polymerase chain reaction (PCR) with allele-specific primers, the specificity of the amplification may depend on various PCR conditions. To avoid non-specific amplification which leads to false-positive results in ASA, we modified both the normal and mutant allele-specific primers so that they would have one constant base mismatch, located at the penultimate 3' position. We confirmed that our modification could inhibit such unfavorable amplification by using as templates genomic DNAs of patients affected with tyrosinase-negative oculocutaneous albinism (OCA). We then analyzed new patients affected with tyrosinase-negative OCA, and based the diagnosis on both the results of a clinical examination and those of a hair bulb test using ASA with the modified allele-specific primers. The results indicated that more than 3 alleles of the tyrosinase gene with a pathological mutation existed in Japanese patients.

Albinism, Oculocutaneous↗
PubMed1995

Prurigo nodularis consists of two distinct forms: early-onset atopic and late-onset non-atopic.

BACKGROUND: Prurigo nodularis (PN) is a characteristic chronic dermatosis of unknown etiology showing severely pruritic nodules mainly on the extremities. Atopic diathesis has been implicated as a contributing factor. OBJECTIVE: Our purpose was to analyze the role of environmental allergens from living organisms in the pathogenesis of PN, to report hypersensitivity against various environmental allergens and to relate this to atopic history in 31 PN patients. METHODS: Positive and negative controls were studied including 52 patients with atopic dermatitis (AD) and 22 healthy controls. RAST, prick tests and scarification patch tests were performed on the patients and specimens from lesions of 8 patients were stained with anti-eosinophil cationic protein (ECP) antibody. RESULTS: The 31 PN patients were divided into two groups, those with a past or present history of AD (PN + AD patients) and those without (PN-only patients). Twenty patients (65%) had PN + AD (median age at onset 19 years) and 11 (35%) had PN only (median age at onset 48 years). Analyses of serum IgE levels. RAST scores, prick test and scarification patch test results revealed that the PN + AD patients showed hypersensitive reactions to the environmental allergens in a pattern almost identical to that noted in AD without PN. In contrast, most of those with PN only did not show any hypersensitivity reactions to the environmental allergens. Histologically, many activated eosinophils, identified by monoclonal antibody to ECP, were observed only in the dermis of the PN+AD patients, in contrast to few eosinophils in the lesion of PN-only patients. CONCLUSIONS: These results indicate that there are two forms of PN: an atopic and a non-atopic one. The PN+AD group is closely associated with AD, being accompanied by cutaneous hypersensitivity to various environmental allergens (a pattern similar to that displayed by AD patients) and has a younger age of onset, whereas the PN-only group, which showed a much older age of onset, does not show any such hypersensitive reactions against these allergens.

Adolescent↗
PubMed1995

Differential effects of selective beta 1-agonist stimulation on epi- and endocardial oxygen tension in anesthetized dogs.

We investigated the effects of selective beta 1 adrenoceptor stimulation on oxygen tension (pO2) in the myocardium of anesthetized dogs. A beta 1-selective full agonist, T-0509 (0.01-0.05 microgram/kg, i.v.), caused positive inotropic and chronotropic effects, and increased left circumflex blood flow, although it did not change arterial blood pressure. These effects were inhibited by bisoprolol (10 micrograms/kg), but not by ICI 118551 (30 micrograms/kg). Under control conditions, subepicardial pO2 (pO2 epi) and subendocardial pO2 (pO2endo) were approximately 33 and 27 mmHg, respectively. T-0509 (0.05 microgram/kg) decreased pO2epi in all cases, with a mean decrease of 2.6 +/- 0.5 mmHg, and this was significantly inhibited by bisoprolol. T-0509 caused an increase (7 out of 10 dogs) or a slight decrease (3 out of 10) in the pO2endo; the mean increment was 2.0 +/- 1.3 mmHg (n = 10). Isoproterenol (0.01-0.05 microgram/kg, i.v.) exerted positive inotropic and chronotropic effects that were sensitive to bisoprolol, and a hypotensive effect that was sensitive to ICI 118551. Isoproterenol caused an increase in blood flow that was sensitive to ICI 118551. Isoproterenol (0.05 microgram/kg) decreased pO2epi in all cases, with a mean decrease of 2.7 +/- 0.5 mmHg, which was significantly inhibited by bisoprolol. Isoproterenol caused an increase (5 out of 10) or a slight decrease (5 out of 10) in the pO2endo; the mean increment was 1.1 +/- 1.2 mmHg (n = 10).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-1 Receptor Agonists↗
PubMed1994

Proinflammatory properties of molluscum bodies.

Molluscum contagiosum, a condition characterized by benign viral tumours, occasionally becomes inflamed and regresses spontaneously, an event probably initiated by a host cell-mediated immune rejection against the lesion, but it inevitably involves the disruption of the epidermal tissue to expose the molluscum bodies to the tissue fluids of the dermis. It has been suggested that the molluscum bodies induce inflammation by a mechanism similar to that involved in ruptured epidermal cysts or in acne. Despite the occasional development of inflammation in molluscum contagiosum, the proinflammatory properties of molluscum bodies have never been studied in vitro. Thus, in the present study we sought to determine whether molluscum bodies exert a proinflammatory effect by inducing neutrophil chemotaxis. When exposed to fresh serum in vitro, water-insoluble components of molluscum bodies activated the alternative complement pathway to produce chemotactic C5a/C5a des Arg. We also found that an aqueous extract of molluscum bodies exerted potent chemotactic activity for neutrophils. Remarkably high amounts of the immunoreactive proinflammatory cytokines IL-8 and GRO alpha were present in the extract even when compared with psoriatic scale extracts. Gel filtration HPLC of the extract demonstrated the presence of neutrophil chemotactic activity over a wide range of molecular mass. These data suggest that disruption of the epidermal wall of molluscum bodies induces acute inflammatory changes by activation of the alternative complement pathway on exposure to the tissue fluids, and that the molluscum bodies themselves release proinflammatory cytokines and other neutrophil chemotactic factors on decomposition.

Chemotaxis, Leukocyte↗