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M Ichihashi

Publications and source records attributed to M Ichihashi.

At least 73 records · Page 4Linked to original sources
PubMed1999

Overexpression of the human homologue of Drosophila patched (PTCH) in skin tumours: specificity for basal cell carcinoma.

The human homologue of the Drosophila segment polarity gene patched (PTCH) has been identified as the gene for the naevoid basal cell carcinoma (BCC) syndrome and has also been shown to be mutated in sporadic BCC. In order to elucidate the specificity of the PTCH abnormality in BCC, we examined normal skin and 12 BCC and 24 other types of tumour from Japanese patients for expression of the PTCH transcript by competitive reverse transcription-polymerase chain reaction, as mutational inactivation of PTCH leads to overexpression of the mutant transcript owing to failure of a negative feedback mechanism. We found a high level of PTCH expression in all 12 BCCs, while 23 of the other tumours and four specimens of normal skin showed no or weak expression of the gene, with the exception of one specimen from a patient with Bowen's disease which had high expression. These results indicate that the PTCH abnormality plays a critical role in the pathogenesis of BCC.

Aged↗
PubMed1999

Higher susceptibility to apoptosis following ultraviolet B irradiation of xeroderma pigmentosum fibroblasts is accompanied by upregulation of p53 and downregulation of bcl-2.

Apoptosis plays an important part as a defence mechanism in eliminating damaged cells. Among the complex factors which regulate apoptosis, the p53 tumour suppressor protein which is induced by DNA damage has been suggested to play a crucial part. Cells from xeroderma pigmentosum (XP) patients, which are defective in nucleotide excision repair, express higher levels of p53 and are highly susceptible to cell death after ultraviolet (UV) irradiation. To examine the relationships between DNA damage, p53 and apoptosis, normal and XP group A fibroblasts were exposed to UVB, and expressions of molecules involved in apoptosis were examined. Apoptosis of XP and normal cells was clearly detected at 48 h after irradiation with UVB at doses of 5 and 40 mJ/cm2, respectively. Cells were positive by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) staining under these exposure conditions. At 6 h after irradiation, p53 protein expression was induced in normal and XP cells at minimal doses of 10 and 2.5 mJ/cm2, respectively. Bcl-2 protein, an inhibitor of apoptosis, was downregulated prior to cell death following UVB exposure at doses that induced apoptosis in both cell types. These results suggest that DNA damage due to UVB induces apoptosis by upregulating proapoptotic molecules such as p53, and by downregulating anti-apoptotic molecules such as Bcl-2.

Apoptosis↗
PubMed1999

The depigmenting effect of alpha-tocopheryl ferulate on human melanoma cells.

Oral vitamin E (alpha-tocopherol, alpha-T) supplementation has been reported to improve facial hyperpigmentation. alpha-Tocopheryl ferulate (alpha-TF) is a compound of alpha-T and ferulic acid connected by an ester bond; ferulic acid is also an antioxidant, and could scavenge free radicals induced by ultraviolet (UV) radiation, and thus maintain the long-lasting antioxidative effect of alpha-T. Our aim was to see whether alpha-TF might be useful as a whitening agent and an antioxidant to improve and prevent facial hyperpigmentation following UV exposure. In this study, the inhibitory effect of alpha-TF on melanogenesis was examined biochemically using human melanoma cells in culture. The results show that alpha-TF, solubilized in ethanol or in 0.5% lecithin, inhibited melanization significantly, as did alpha-T at a concentration of 100 microg/mL, without inhibiting cell growth. This phenotypic change was associated with inhibition of tyrosinase and 5, 6-dihydroxyindole-2-carboxylic acid polymerase activities, and the degree of inhibition was dose dependent. No significant effect on DOPAchrome tautomerase activity was observed. alpha-TF did not directly inhibit tyrosinase activity of the large granule fraction extracted from human melanoma cells, and Western blotting revealed that there were no changes in protein content or in molecular size of tyrosinase, tyrosinase-related protein (TRP)-1 or TRP-2. Therefore, the inhibition of tyrosinase activity by alpha-TF might be due to effects at the post-translational level, and possibly by a secondary molecule activated by alpha-TF. These results suggest that alpha-TF is a candidate for an efficient whitening agent which suppresses melanogenesis and inhibits biological reactions induced by reactive oxygen species.

Antioxidants↗
PubMed1999

UVA-induced immune suppression through an oxidative pathway.

Although ultraviolet B (UVB) irradiation induces local immune or systemic immune suppression, depending on the dose, the immune suppression by ultraviolet A (UVA) has not been fully investigated. In this study, we investigated the effect of UVA on the immune response in vitro and in vivo. The effect of UVA on the antigen-presenting function of epidermal cells was measured in terms of antigen-specific T cell proliferation. A murine epidermal cell suspension was exposed to UVA in vitro, pulsed with trinitrobenzenesulfonic acid, and cultured with T cells prepared from syngeneic mice previously sensitized with trinitrochlorobenzene. UVA (5-20 J per cm2) suppressed the antigen-presenting function of epidermal cells in a dose-dependent manner, accompanied with suppression of the expression of costimulatory molecules on Langerhans cells. In order to investigate the effect of an antioxidant on the immune suppression, an epidermal cell suspension was irradiated with UVA in the presence or absence of glutathione. The suppressions of antigen-presenting function and ICAM-1 expression were significantly prevented by glutathione in a dose-dependent manner. Further, the effect of UVA on the immune response at the induction phase of contact hypersensitivity was evaluated in terms of lymph node cell proliferation ex vivo. UVA irradiation suppressed the endogenous proliferation of lymph node cells in trinitrochlorobenzene-painted mice, and this suppression was significantly reversed by the application of glutathione to the skin during irradiation. These results suggest that UVA-induced immune suppression may be mediated by reactive oxygen species, at least in part.

Animals↗
PubMed1999

Enhanced expression of melanocortin-1 receptor (MC1-R) in normal human keratinocytes during differentiation: evidence for increased expression of POMC peptides near suprabasal layer of epidermis.

Immunohistochemical staining of human skin specimen showed the stronger localization of proopiomelanocortin peptides near the suprabasal layer of the epidermis, where keratinocytes are mostly differentiated. To test the possibilities of whether the production of proopiomelanocortin peptides or their receptor-binding activity or both is increased during differentiation of keratinocytes, we treated the cells in culture with Ca2+ to induce their differentiation. The production of proopiomelanocortin peptides and its gene expression were not induced significantly, but the binding ability of melanocortin receptor, as well as its gene expression were stimulated by Ca2+. Ultraviolet B irradiation, an inducer of differentiation, stimulated both proopiomelanocortin production and melanocortin receptor expression. These data show that normal human keratinocytes express melanocortin receptor similar to melanocytes, and that it is induced during differentiation.

Adrenocorticotropic Hormone↗
PubMed1999

Pharmacokinetics of 10B-p-boronophenylalanine in tumours, skin and blood of melanoma patients: a study of boron neutron capture therapy for malignant melanoma.

To optimize the neutron dose for boron neutron capture therapy (BNCT), the boron-10 (10B) concentration kinetics of 10B-p-boronophenylalanine (BPA) were analysed in 22 melanoma patients with primary or metastatic melanomas who received BPA and subsequently underwent BNCT or surgery. The blood concentration in nine patients receiving 179.7+/-14.9 mg/kg BPA increased with time during intravenous infusion, peaked at the end of administration and decreased thereafter. The peak values at the end of administration were 9.4 2.6 microg 10B/g blood, and half-lives for the initial and second components of the blood clearance were 2.8 and 9.2 h, respectively. Skin concentrations in the 10 patients varied from case to case; however, skin-to-blood ratios were relatively constant at 1.31+/-0.22 during the 6 h after the end of administration. Boron concentrations in the tumours resected from the seven patients who were operated on decreased in parallel to the blood values, the tumour-to-blood ratio being relatively constant at 3.40+/-0.83. The present analytical data of BPA pharmacokinetics support our previous approach for optimizing the timing of irradiation and setting the neutron flux large enough for tumour eradication but still tolerable for normal skin.

Adult↗
PubMed1999

Expression of tyrosinase, TRP-1 and TRP-2 in ultraviolet-irradiated human melanomas and melanocytes: TRP-2 protects melanoma cells from ultraviolet B induced apoptosis.

Tyrosinase related protein (TRP)-1 and TRP-2 are known to regulate the quality of melanin, and recently their potential role in inhibiting apoptosis have also been reported. To study the role of tyrosinase, TRP-1 and TRP-2 in the growth, differentiation and cell death of ultraviolet B (UVB) irradiated melanocytes, the expression of these proteins in amelanotic and melanotic cells was examined. Expression of tyrosinase and TRP-1 correlated with melanin content, which was upregulated after repeated irradiation of melanotic cells by low doses of UVB. In contrast, the expression and activity of TRP-2 correlated with cell proliferation, but not with pigmentation. In one melanotic melanoma cell line, significant suppression of cell proliferation was observed after low or high doses of UVB irradiation, possibly due to apoptotic changes. TRP-2 expression was remarkably reduced in UVB-irradiated cells, and transfection with TRP-2 expression vector rescued these cells from UVB-induced apoptosis. These results indicate that TRP-2 expression is closely associated with the regulation of cell growth/survival of melanocytes exposed to UVB and that TRP-2 plays a role in protecting melanoma cells from UVB-induced apoptosis.

Adult↗
PubMed1999

A case of multiple sebaceous epithelioma: analysis of microsatellite instability.

Sebaceous gland tumor is a rare disease that is a sign of Muir-Torre syndrome, an autosomal, dominantly inherited genodermatosis characterized by the presence of at least one sebaceous gland tumor and a minimum of one internal malignancy. Recent studies have indicated that defective DNA mismatch repair occurs in Muir-Torre syndrome. Cutaneous lesions may occur before diagnosis of the internal cancer. We describe a 64-year-old male patient with multiple sebaceous epitheliomas with no evident internal malignancy. Microsatellite instability, determined by examining dinucleotide CA repeats at the microsatellite loci, was observed in DNA from one sebaceous epithelioma but not from the other two sebaceous epitheliomas or from one basal cell epithelioma with sebaceous differentiation, suggesting that this condition is unlikely to be due to germ-line mutation of mismatch repair genes.

Adenocarcinoma, Sebaceous↗
PubMed1999

High levels of 8-hydroxy-2'-deoxyguanosine appear in normal human epidermis after a single dose of ultraviolet radiation.

Major photoproducts induced by carcinogenic ultraviolet (UV) radiation are the cylobutane pyrimidine dimers (CPDs) and pyrimidine-pyrimidone (6-4) photoproducts (6-4 PPs). 8-Hydroxy-2 -deoxyguanosine (8-OHdG) is also a DNA base-modified product generated by reactive oxygen species in conditions of ultraviolet stress, Although UVB-induced CPDs and 6-4 PPs have been investigated in animal and human skin, little is known about the role of 8-OHdG in UVB-induced human skin damage or carcinogenesis. Normal human skin from three volunteers was exposed to UV radiation, and the time course of induction and removal of 8-OHdG was examined by immunohistochemical analysis with catalysed signal amplification on formalin-fixed paraffin sections. Formation of CPDs and 6-4 PPs was also examined by immunostaining on the same skin specimens. Control epidermis with no exposure to UV radiation showed little nuclear staining of 8-OHdG, but an increased level of 8-OHdG was clearly observed in epidermis biopsied after irradiation. Induced 8-OHdG can rapidly be removed from nucleus during the first 24-48 h, as the staining intensity diminished gradually, almost reaching the control level by 72-96 h after irradiation. Staining for CPDs or 6-4 PPs revealed induction of these photoproducts in human skin, although 6-4 PP-positive cells disappeared more rapidly than those that stained for CPDs or 8-OHdG. Together with protective effect of antioxidants, our results indicate that not only CPDs and 6-4 PPs but also 8-OHdG may play a significant part in UV carcinogenesis.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

Horizontal and vertical pigment spread into surrounding piebald epidermis and hair follicles after suction blister epidermal grafting.

Following the earlier description of Carnot and Deflandre in 1896, pigment spread phenomenon in mammals was investigated using immunogenetically marked melanocytes (Billingham and Silver, Quart. Rev. Biol. 1960 35: 1-40; Billingham and Silver, Ann. N.Y. Acad. Sci. 1963 100: 348-363). In spite of a number of similar studies on vitiligo lesions, detailed evaluation of pigment spread in piebald lesions has not been reported. To gain further insight into the pigment spread phenomenon in human skin, five piebald patients were studied, on whom suction blister epidermal grafting therapy onto piebald patches was performed. In the present study, pigmentation of all epidermal grafts from normally pigmented areas spread horizontally. It was also found that pre-existing white hairs in recipient sites became pigmented within 1 year after epidermal grafting. Immunofluorescence studies using melanocyte-specific antibody NKI/beteb revealed the newly induced presence of melanocytes in the newly pigmented hair follicles. Further, to study the possible mechanisms inhibiting melanocyte migration from normal skin into piebald lesions, epidermis was grafted from border zones (containing both normal and piebald skin) into the center of hypopigmented lesions. Melanocytes clearly migrated through the border zone of grafted epidermis into surrounding recipient hypopigmented sites.

Epidermis↗
PubMed1999

Upregulation of mRNA for the melanocortin-1 receptor but not for melanogenic proteins in macrophage x melanoma fusion hybrids exhibiting increased melanogenic and metastatic potential.

Fusion of mouse peritoneal macrophages or human blood monocytes with weakly metastatic mouse Cloudman S91 melanoma cells resulted in hybrids with enhanced metastatic potential (Rachkovsky et al., 1998. Clin. Exp. Metastasis, 16: 299-312). With few exceptions, such hybrids also showed increased basal- and MSH-induced pigmentation, at least in part through increased N-glycosylation of melanogenic proteins (Sodi et al., 1998. Pigment Cell Res., 11: 299-309). Here we report analyses regarding expression of the melanocyte-stimulating hormone (MSH) receptor (melanocortin-1 receptor, MC1-R) and the melanogenic proteins, tyrosinase (E.C. 1.14.18.1), tyrosinase-related protein 1 (TRP-1), and the tyrosinase-related protein 2 (TRP-2, E.C. 5.3.2.3), by a panel of cell lines consisting of parental Cloudman S91 melanoma cells, macrophages from DBA/2J mice, artificially derived macrophage x melanoma hybrids of high and low metastatic potential, and a naturally occurring highly metastatic hybrid between a Cloudman S91 tumor cell and a DBA/2J tumor-infiltrating cell. We show that incubation of cells with MSH/isobutylmethylxanthine (IBMX) resulted in strong melanogenic and morphologic responses in high metastatic hybrids compared to parental cells and the low metastatic hybrid, and that high metastatic hybrids exhibit increased mRNA expression for MC1-R accompanied by increased 125I-alphaMSH binding. Although tyrosinase activity and the protein level for tyrosinase and TRP-2, but not for TRP-1, were increased in the high metastatic hybrids versus the other cells, no significant changes in mRNA either for tyrosinase or for TRPs were observed in them. Furthermore, unlike tyrosinase, the abundance and gel mobility pattern of TRP-2 did not correlate with changes in activity in all hybrids and parental melanoma cells. The results suggest that although the activity MC1-R and tyrosinase correlate with enhanced basal as well as MSH-induced melanogenesis in metastatic/melanotic hybrids, their expression is differentially regulated, i.e., regulation of MC1-R while at transcriptional level, the TRPs are primarily regulated via post-transcriptional mechanisms in high metastatic hybrids.

1-Methyl-3-isobutylxanthine↗
PubMed1999

Influence of chronic UV exposure and lifestyle on facial skin photo-aging--results from a pilot study.

In order to better understand the effect of chronic sun exposure on facial skin photo-aging and to identify the factors affecting it, we planned a study in two areas in Japan, Akita and Kagoshima, which correspond to the low and high sun exposure environments, respectively. As a first step, we conducted a pilot study in the two areas, examining 195 subjects. Hyper-pigmentation and wrinkling were measured with a high-resolution digital video imaging system. As expected, people in Kagoshima had darker skin, higher visual grades of facial hyper-pigmentation, and more facial wrinkles than people in Akita, reflecting the difference of UV exposure levels in the two areas. Both the grades of hyper-pigmentation and number of wrinkles increased in a roughly linear fashion with the advancement of age. On the other hand, the effect of gender was different in those two skin photo-aging parameters. Women had higher hyper-pigmentation grades (P = 0.012) and less wrinkles (P = 0.004) than men. Interestingly, post-menopausal women had higher grades of hyper-pigmentation than pre-menopausal women. Neither sun exposure index for darkness nor wrinkling showed any significant differences by menopausal status. In this pilot study, we collected information on various factors, including life-styles. The results of detail analysis will be presented elsewhere. In the present analysis, we found that the grade of hyper-pigmentation was not related to total hours spent outside in life but was affected by various factors, including toe-nail zinc levels. On the other hand, the number of wrinkles was significantly related to total hours spent outside in life. The most important risk factors of non-melanoma skin cancer are chronic sun exposure, age and male sex. All of them are strongly related to higher levels of UV exposure. The present study confirmed that chronic sun exposure, age and male sex were strong risk factors of the wrinkle number. The number of wrinkles was significantly related to total hours of sun exposure in life, increased in a roughly linear fashion with the advancement of age, and was larger in men than in women. In epidemiological studies of UV-related skin cancer, the number of wrinkles, which can be easily measured with a high-resolution digital video imaging system as shown in this study, may be a good marker of total sun exposure in life.

Adult↗
PubMed1999

Incidence of skin cancers and precancerous lesions in Japanese--risk factors and prevention.

An examination of the occurrence of skin cancers and precancerous lesions among residents of Kasai City (34 degrees 56' N) since 1992, and of le-island (25 degrees 10' N) since 1993, has been conducted to characterize the prevalence and incidence of skin cancers in Japanese people and to evaluate risk and preventive factors. The mean prevalence of actinic keratosis (AK) in residents of Kasai City and le-island was 203.33 and 756.26, respectively, indicating that twice the dose of UVB radiation causes a 3-4 fold higher incidence of AK, although life styles, including types of occupations, differ in these two locations. Working outdoors, having skin type I and/or a history of severe sunburns during childhood were found to be important risk factors, while the use of cosmetics after 20 years of age was a protective factor, for AK and possibly for skin cancers. Further, sunscreen use among males over 60 years of age in Kasai City from 1994 through 1998 suggested that sunscreen use may reduce AK development in older people. Four and 12 cases of skin cancers were found in residents of Kasai City (from 1992 to 1997) and on le-island (from 1993 to 1998), respectively. These numbers are too small to establish the prevalence of skin cancer in Japanese, but indicate that people living in areas of higher ambient solar radiation have a higher incidence of skin cancer. This epidemiological study strongly indicates that sun protection is the major modality to reduce sun-induced cutaneous tumors in Japanese.

Adult↗
PubMed1999

Possible involvement of proteolytic degradation of tyrosinase in the regulatory effect of fatty acids on melanogenesis.

The purpose of this study was to investigate the mechanism of fatty acid-induced regulation of melanogenesis. An apparent regulatory effect on melanogenesis was observed when cultured B16F10 melanoma cells were incubated with fatty acids, i.e., linoleic acid (unsaturated, C18:2) decreased melanin synthesis while palmitic acid (saturated, C16:0) increased it. However, mRNA levels of the melanogenic enzymes, tyrosinase, tyrosinase-related protein 1 (TRP1), and tyrosinase-related protein 2 (TRP2), were not altered. Regarding protein levels of these enzymes, the amount of tyrosinase was decreased by linoleic acid and increased by palmitic acid, whereas the amounts of TRP1 and TRP2 did not change after incubation with fatty acids. Pulse-chase assay by [35S]methionine metabolic labeling revealed that neither linoleic acid nor palmitic acid altered the synthesis of tyrosinase. Further, it was shown that linoleic acid accelerated, while palmitic acid decelerated, the proteolytic degradation of tyrosinase. These results suggest that modification of proteolytic degradation of tyrosinase is involved in regulatory effects of fatty acids on melanogenesis in cultured melanoma cells.

Animals↗
PubMed1999

[Role of Candida allergen in atopic dermatitis and efficacy of oral therapy with various antifungal agents].

We studied whether fungal allergens play a role in exacerbating the clinical symptoms of atopic dermatitis (AD). We found that the percentage of the patients who showed CAP-RAST positive (2 < or = score) to Candida albicans (Ca) was significantly higher in the patients with severe symptoms and high serum IgE level than those with mild symptoms and lower IgE. This was also true for the patients with CAP-RAST positive to Pityrosporum ovale (Po). AD patients with their symptoms localized to head and neck showed significantly higher tendency to have positive CAP-RAST (2 < or = score) to Ca and Po when compared to those with their eruption distributing to the extremities. We then evaluated the efficacy of oral therapy with antifungal agents in 140 cases of refractory AD with positive CAP-RAST to Ca. Good or excellent response was obtained in 60% with fluconazole, 35% with itraconazole, 31% with amphotericin B, 28% with nystatin. The present finding that amphotericin B and nystatin, both of which are not absorbed through intestine, were effective for approximately a third of the patients indicates that Ca in the intestine plays an important role in triggering AD symptoms. Fluconazole was more effective than amphotericin B and nystatin, suggesting that fungal colonizing in other parts of the body but the digestive tract also play a role in the exacerbation of AD symptoms.

Administration, Oral↗