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Biomedical subjects

H Tagami

Publications and source records attributed to H Tagami.

At least 73 records · Page 4Linked to original sources
PubMed1996

Phospholipases induce melanogenesis in organ-cultured skin.

Guinea pig skin becomes more pigmented following exposure to UV rays. This melanization was accompanied by enhanced intensity of tyrosinase-staining and increased number of tyrosinase-positive melanocytes (MELty+), with resultant enhancement of melanin synthesis. To clarify the regulatory mechanism for melanization following UV irradiation, organ-cultured guinea pig skins have been used to examine their melanogenic responses to exogenous stimulation. This organ culture system responded well to UV irradiation, by increasing melanogenic activity. Also, in this system, phospholipases (PL), arachidonic acid, interleukin-1 alpha and melanocyte-stimulating hormone, but not endothelin-1 or phosphatidylinositol-specific PLC (PI-PLC), stimulated melanogenesis to various extents as indicated by the number of MELty+ and morphological changes. Among them, the PLA2 and PLD were found to have a potent stimulatory property for melanocytes. They might affect melanocytes directly or indirectly through an effect on keratinocytes. These results suggest that PLA2 and PLD play a key role in epidermal hyperpigmentation after UV irradiation or inflammation.

Animals↗
PubMed1996

Clinicopathological study of acral melanoma in situ in 44 Japanese patients.

BACKGROUND: Acral lentiginous melanoma (ALM) has been a major focus of interest in Japan in the last 2 decades. A remarkable improvement recently made in the prognosis of ALM at our institution may possibly be explained by early detection including melanoma in situ. OBJECTIVE: We have retrospectively studied 44 cases of melanoma in situ in the past 25 years from 1970 to 1994, 61% of which have been seen in the last 5 years. RESULTS: Of 190 cases of invasive malignant melanoma including 20 melanomas involving the mucous membrane, 96 were ALM. Accordingly, the number of cases of melanoma in situ involving the acral regions was also prominent. Of 44 melanomas in situ, 29 occurred in the acral regions. Eight lesions localized on the face were compatible with lentigo maligna both clinically and histologically. All 6 mucosal lesions occurred on the oral mucosa. The remaining lesion appeared on the back of a psoriatic patient treated with photochemotherapy. Forty-two specimens showed histologically a lentiginous proliferation including atypical solitary cells within the lower portion of the epidermis, especially in the basal layer. The remaining 2 specimens were histologically of the pagetoid type. CONCLUSION: Corresponding to the fact that ALM are predominant in the Japanese, the most common sites of melanoma in situ are also the acral regions.

Adolescent↗
PubMed1996

Contact dermatitis of the ear due to a rubber earplug.

We report a case of contact dermatitis of the ear canal due to rubber earplugs. A 31-year-old Japanese woman had a 2-year history of eczema confined to her ears. Applications of various topical steroids had shown no beneficial effect upon her lesions. Considering contact dermatitis as a possible diagnosis we performed patch tests. Positive eczematous patch test results were obtained with mercaptobenzothiazole, tetramethylthiuram disulfide and her rubber earplugs, which she had used whenever she took a bath. The eruption cleared after the patient stopped using the rubber earplugs.

Adult↗
PubMed1996

Congenital plantar melanocytic nevus with satellite lesions.

We report a case of a congenital melanocytic nevus accompanied by a mucous cyst and satellite pigmented macules on the undersurface of the left great toe in a 17-year-old Japanese man. Myxoid change was confirmed by the discharge of viscous liquid when conducting biopsy of the tumor. Besides such an unusual clinical feature of the tumor, accompanying satellite lesions led us initially to consider the possibility of malignant melanoma. However, a biopsy specimen obtained from the tumor revealed the typical features of intradermal type melanocytic nevus. In a specimen obtained from the satellite pigmented lesion, there was a small mass of nevus cells underneath the basement membrane zone, suggestive of having originated from the spread of nevus cells through lymphatic vessels.

Adolescent↗
PubMed1996

Coexistence of multiple perifollicular fibromas and colonic polyp and cancer.

Perifollicular fibroma (PFF) is a rare cutaneous hamartoma that shows differentiation to the connective tissue sheath of the hair follicle. It may be solitary or multiple; the latter has been suggested to exhibit autosomal dominant inheritance and association with colonic polyposis. We report a 72-year-old Japanese female with multiple PFF on the face, possibly familial, who developed colon cancer in addition to colonic polyps.

Adenocarcinoma↗
PubMed1996

Epidemiology and prognosis of subungual melanoma in 34 Japanese patients.

The incidence of malignant melanoma is much lower in the Japanese than in caucasians. However, amongst the various types of malignant melanoma, the subungual and periungual sites are commonly found in the Japanese. One hundred and fifty-one cases of cutaneous malignant melanoma were seen over a 25-year period at our hospital. We found that, in 34 patients (23%), the subungual region was involved, a high frequency for one institution. We have analysed these patients and looked at their treatment. The finger nails were affected in 21 cases (62%) and the toe nails in 13 cases (38%). The thumb nails or great toe nails were affected in 25 of the 34 patients (73%). In 25 patients, histopathological features of acral lentiginous melanoma were found, with four cases of superficial spreading melanoma and five of nodular amelanotic melanoma. Of the latter group, four mimicked fibrous histiocytic tumour, and one was a desmoplastic malignant melanoma. The proportion of patients presenting with stage III disease decreased after 1982, with a corresponding increase in patients whose tumour thickness was less than 4 mm (stage II). Concurrently, the prognosis for subungual malignant melanoma improved. The 5-year survival rate in each of the periods 1969-82 and 1983-93 was 53 and 87%, respectively. This is similar to that found in plantar malignant melanoma and is felt to be due to a greater public awareness of the condition and to the introduction of effective chemotherapy (the DTIC-AC nitrosurea-vincristine (DAV) regimen). Although the frequency of malignant melanoma is rather low in the Japanese, our data indicate that there is a high incidence of subungual malignant melanoma. Public awareness of the early stage of malignant melanoma seems to have improved prognosis.

Adult↗
PubMed1996

The role of two endogenous proteases of the stratum corneum in degradation of desmoglein-1 and their reduced activity in the skin of ichthyotic patients.

We investigated the role of stratum corneum (SC) trypsin-like and chymotrypsin-like serine proteases in the degradation of desmoglein-1 (DSG-1) in the SC sheet. DSG-1, whose presence in the SC sheet was confirmed by Western blot analysis, was degraded completely during incubation of the SC sheet in Tris buffer. The degradation of DSG-1 was inhibited by the addition of protease inhibitors, such as aprotinin or a mixture of leupeptin and chymostatin. Either leupeptin or chymostatin alone did not inhibit its degradation. These results indicated that both trypsin-like and chymotrypsin-like serine proteases are involved in the degradation of DSG-1. We further examined the activities of the two proteases in the SC obtained from patients with ichthyosis vulgaris, in whom SC desquamation is abnormal. The enzymatic activities measured using synthetic substrates were significantly decreased in these ichthyotic SC samples. This result supports the idea that these proteases play an important role in normal SC desquamation.

Adolescent↗
PubMed1996

Oral prednisone in the treatment of acne agminata.

Acne agminata (lupus miliaris disseminatus faciei), once regarded as a tuberculide, is a facial granulomatous disease still seen in young adults in Japan, despite a decrease in the incidence of tuberculosis. Although most lesions regress within a few years, even without treatment, disfiguring scars remain on the face. We have evaluated the efficacy of low dose oral prednisone therapy because, in the past, there has been no satisfactory therapy for this condition. We have treated four patients with acne agminata with prednisone, at first 10 mg daily for 2 weeks, decreasing to 5 mg daily for 3 months. This modest dosage was found to give an excellent result in three patients and a poor result in one whose treatment was started at a much later stage of the disease than in the others. Acne agminata can be cured without scar formation when oral steroids are started in an early phase of the disease.

Administration, Oral↗
PubMed1996

Carbamazepine induced erythroderma with systemic lymphadenopathy.

We describe a 13-year-old girl with carbamazepine (CBZ)-induced erythroderma associated with marked generalized lymphadenopathy, a very rare form of CBZ hypersensitivity. The results of lymphocyte stimulation test (LST) and patch testing provided valuable evidence for distinguishing CBZ hypersensitivity from immunoblastic lymphadenopathy (IBL) and infectious mononucleosis (IM). An increased LST value was the only clue leading us to suspect a hypersensitivity reaction against CBZ at a peak stage of the skin eruption. In contrast, CBZ patch testing, which was negative at that time, became positive when the erythroderma regressed after discontinuation of CBZ. These findings suggest that LST can be a useful tool in diagnosing similar cases of hypersensitivity reactions to CBZ and other drugs, especially when patch test results are negative.

Adolescent↗
PubMed1996

Functional analyses of the stratum corneum in scars. Sequential studies after injury and comparison among keloids, hypertrophic scars, and atrophic scars.

OBJECTIVE: To characterize the functional properties of the stratum corneum (SC) of various scars. DESIGN: A prospective cohort study. SETTING: University hospital medical center. PATIENTS: Thirty-two consecutive patients surgically treated for various skin diseases and 26 consecutive patients with hypertrophic scars or keloids. MAIN OUTCOME MEASURES: Noninvasive bioengineering measurements of functional properties of the SC, such as transepidermal water loss (TEWL), high-frequency conductance, and SC turnover time. RESULTS: The SC barrier function assessed by TEWL was found to be a better parameter for the functional evaluation of scars than the hydration state of the skin surface measured by high-frequency conductometry. In general, the SC on the scars of deeper wounds in the dermis took longer to normalize functionally than the SC on the scars of superficial wounds, especially on the high compared with the abdomen. Thus, elevated levels of TEWL observed on scars at the donor sites of split-thickness grafts normalized between 200 and 400 days in contrast to fewer than 50 days for those of subepidermal erosions. Both TEWL and high-frequency conductance remained high in hypertrophic scars and keloids, and the SC involved showed a faster turnover time than that of adjacent normal skin. CONCLUSIONS: Scars, a proliferative change of the dermis, can be objectively evaluated according to functional abnormalities of the SC, because the dermis has a close relationship with the epidermis and with the SC. The functional characteristics of the SC of fresh scars and those of hypertrophic scars and keloids resemble those of retinoid-treated skin, rather than those found in epidermal hyperproliferative conditions such as psoriasis and dermatitis.

Abdomen↗
PubMed1995

Role of CRP in transcription activation at Escherichia coli lac promoter: CRP is dispensable after the formation of open complex.

The role of cAMP receptor protein (CRP) in transcription activation at the Escherichia coli lac promoter was investigated focusing on the steps after the formation of open complex. Although CRP binding to the lac DNA is stabilized in the ternary open complex, a high concentration of heparin dissociates CRP from the open complex without affecting the interaction between RNA polymerase and promoter, resulting in a binary complex. The release of CRP is directly shown by Western blotting and DNase I footprinting. The binary complex exhibits a slightly increased gel mobility compared to the ternary complex. The binary complex retains the characteristics of the open complex in footprinting pattern which is essentially identical with that of the open complex of the lac UV5 promoter. The binary complex is competent for transcription. These results indicate that CRP is not necessary for the maintenance of active open complex. In addition, the removal of CRP does not increase the production of abortive RNAs. We conclude that the contact between CRP and RNA polymerase is not essential for transcription activation after the formation of the open complex at the lac promoter. In other words, the role of CRP in the lac promoter is restricted to the steps up to the formation of open complex.

Bacterial Proteins↗
PubMed1995

Murine epidermal Langerhans cells express CD48, which is a counter-receptor for mouse CD2.

It has recently been demonstrated that CD48, which is expressed on T cells, B cells, thymocytes and splenocytes, is a ligand for mouse CD2 and that it can function as one of the costimulatory molecules in the activation of T cells. In this study, we examined the expression of CD48 on epidermal Langerhans cells (LC), which are potent antigen-presenting cells in the skin. Both freshly isolated and short-term-cultured LC were shown to express CD48 by flow cytometry. In contrast to most of the adhesion molecules expressed on LC, CD48 expression on short-term-cultured LC did not differ significantly from that on freshly isolated LC. We also examined the contribution of CD48 to antigen presentation by LC. We stimulated the myoglobin-specific T-cell clone, TK.G4, and allogeneic splenic T cells with freshly isolated LC and cultured LC, respectively, in the presence of various concentrations of anti-CD48 monoclonal antibody (mAb). Even at the concentration of 30 micrograms/ml, however, the anti-CD48 mAb did not show any inhibitory effects on either allogeneic or antigen-specific T-cell proliferation, whereas at a concentration 10 micrograms/ml, the anti-CD48 mAb significantly suppressed the proliferation of spleen cells stimulated with phytohaemagglutinin (PHA). These findings show that LC persistently express CD48, although its direct role in antigen presentation has not yet been clarified in vitro.

Animals↗
PubMed1995

Hydroa vacciniforme-like lymphomatoid papulosis in a Japanese child: a new subset.

An 8-year-old Japanese girl had a 9-month history of a self-healing papulovesicular eruption on her face, scalp, and neck that resembled hydroa vacciniforme (HV). Histologically, there was a dense infiltration of small lymphocytic cells and scattered large atypical cells expressing CD30. Study of gene rearrangement showed no monoclonality in the infiltrating cells. To our knowledge, this is the second case of lymphomatoid papulosis with clinical features resembling HV. However, we also found descriptions in the literature of two other Japanese children with malignant lymphoma who both initially had clinical features resembling HV. These findings suggest that these cases of HV-like disease constitute a subset of lymphomatoid papulosis that is highly likely to progress to malignant lymphoma.

Child↗
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↗