Search PubMed⌕ Search

Biomedical subjects

M Ichihashi

Publications and source records attributed to M Ichihashi.

At least 91 records · Page 5Linked to original sources
PubMed1999

Distribution and intracellular localization of a mouse homologue of Ca2+/calmodulin-dependent protein kinase Ibeta2 in the nervous system.

Ca2+/calmodulin-dependent protein kinases (CaMKs) are believed to play important roles in the development and function of the nervous system. We report here the identification and expression of mouse CaMKIbeta (mCaMKIbeta), in particular mCaMKIbeta2, an isoform of mCaMKIbeta. During embryogenesis, the mCaMKIbeta2 gene is expressed mainly in the nervous system, including brain, spinal cord, trigeminal ganglion, and retina. Within the CNS, the expression of mCaMKIbeta2 is detected in the mantle zone, but not in the ventricular zone, suggesting its possible involvement in the differentiation of neurons. In the adult brain, mCaMKIbeta2 transcripts are detected at high levels in the anterior olfactory nuclei, piriform cortex, septal nuclei, bed nuclei of the stria terminalis, hippocampal pyramidal cells, dentate granule cells, amygdala, hypothalamic nuclei, parabrachial nucleus, and nucleus of the solitary tract. The distinct gene expression pattern suggests that mCaMKIbeta2 may also be involved in different mature neuronal functions from other CaMKs. In addition, mCaMKI/beta2 proteins are localized to the cytoplasm and nuclei, but not to nucleoli, suggesting that mCaMKIbeta2 proteins might be involved in the cytoplasmic and nuclear signal transduction of the nervous system.

Amino Acid Sequence↗
PubMed1998

Linoleic acid and alpha-linolenic acid lightens ultraviolet-induced hyperpigmentation of the skin.

This study was conducted to evaluate the effects of unsaturated fatty acids on ultraviolet-induced hyperpigmentation of the skin. An efficient lightening effect was observed following topical application of linoleic acid or alpha-linolenic acid to UV-stimulated hyperpigmented dorsal skin of brownish guinea pigs. The number of melanocytes in the treated skin was similar to the number in the skin of the pigmented control, indicating that the pigment-lightening effect was not due to depletion of melanocytes. In vitro experiments using cultured murine melanoma cells showed that melanin production was inhibited most effectively by alpha-linolenic acid, followed by linoleic acid and then by oleic acid. Furthermore, the turnover of the stratum corneum, which plays an important role in the removal of melanin pigment from the epidermis, was accelerated by linoleic acid and by alpha-linolenic acid. Taken together, the results suggest that the pigment-lightening effects of linoleic acid and alpha-linolenic acid are, at least in part, due to suppression of melanin production by active melanocytes, and to enhanced desquamation of melanin pigment from the epidermis.

Administration, Topical↗
PubMed1998

Tissue distribution of a melanoma-associated antigen D-1 immunogenic in patients with melanoma.

A human melanoma-associated antigen D-1 was recently identified by screening an expression cDNA library derived from mRNA of cultured melanoma cells with sera of melanoma patients. The aim of this study is to present in vivo expression and precise distribution of D-1 in normal tissues and benign or malignant neoplasms. By in situ hybridization, we found that the D-1 mRNA was exclusively expressed in the cytoplasms of melanoma cells, but not in keratinocytes, fibroblasts and lymphocytes adjacent to melanoma nests. Further immunohistochemical studies revealed that the expression of D-1 antigen was distributed to both the surface and cytoplasm of melanoma cells, indicating that D-1 antigen can be recognized by killer T lymphocytes or antibodies in vivo. No significant mRNA nor peptide of D-1 was detected in basal cell carcinoma, squamous cell carcinoma and other benign tumors such as melanocytic nevi and seborrheic keratosis. We also confirmed that D-1 mRNA and peptide were not expressed in normal organs by dot blot hybridization and western blot analysis, respectively. These results will assess the suitability of recombinant D-1 protein to implement active specific immunotherapy against melanoma.

Animals↗
PubMed1998

IL-12 promotes the accessory cell function of epidermal Langerhans cells.

The objective of this study was to investigate the effects of cytokines regulating cutaneous immune responses, on the accessory cell function of epidermal cells (EC). EC were treated with various cytokines, and the accessory cell function of the cytokine-pretreated EC was examined by the allogeneic mixed epidermal cell-lymphocyte reaction (MECLR). Among the cytokines examined, IFN-gamma- and IL-12-pretreated EC augmented IFN-gamma production in the MECLR, while none of the other cytokines was effective. However, the cytokine-pretreated EC did neither affect T cell proliferation nor IL-4 production in the MECLR. Next we attempted to analyze the mechanisms by which IL-12-pretreated EC increase IFN-gamma production in the MECLR. Endogenous IFN-gamma produced during the IL-12 pretreatment of EC was found to play only a minor role in modulating the function of EC. The expression of MHC class II, CD80 and CD86 on EC was not affected by IL-12. On the other hand, soluble mediators that induce IFN-gamma production during the MECLR containing IL-12-pretreated EC were identified as endogenously produced IL-12 (the major mediator) and IL-18 (the minor mediator). Furthermore, the results of depletion experiments indicate that IL-12 promotes the accessory cell function of Langerhans cells to responder T cells in inducing IFN-gamma production in the MECLR.

Adjuvants, Immunologic↗
PubMed1998

Immunoreactivity of alpha-melanocyte-stimulating hormone, adrenocorticotrophic hormone and beta-endorphin in cutaneous malignant melanoma and benign melanocytic naevi.

Melanocyte-stimulating hormone (MSH) has been reported to enhance the experimental metastatic behaviour of melanoma cells in the mouse model. alpha-MSH production and MSH receptor (melanocortin 1 receptor gene) expression have been detected in cultured normal human melanocytes and metastasized melanomas. The exact role of MSH in the metastatic behaviour of human melanoma cells is, however, not yet known. To clarify a possible role of proopiomelanocortin (POMC)-derived peptides, including alpha-MSH, in melanoma development and progression, we analysed immunohistochemically the localization of alpha-MSH adrenocorticotrophic hormone (ACTH) and beta-endorphin in various kinds of benign pigmented naevocytic lesions and malignant melanomas. Three of 21 samples of common and dysplastic naevi showed detectable alpha-MSH staining in naevus cells, and five and six of 15 samples were weakly positive for ACTH and beta-endorphin staining, respectively. In melanoma samples, 24 of 45, 23 of 39 and 30 of 42 samples showed positive staining with alpha-MSH, ACTH and beta-endorphin antibodies, respectively. Furthermore, staining for all three antibodies was noted to be more intense and diffuse in samples of nodular melanoma, vertically growing acral lentiginous melanoma and superficial spreading melanoma as well as metastatic lesions compared with those of naevi. Although it is yet to be determined whether or not this strong staining for POMC-derived peptides in advanced melanoma cells indicates a role of autocrine or paracrine regulation, our results suggest a possible involvement of POMC gene products in melanoma progression.

Adrenocorticotropic Hormone↗
PubMed1998

Modulation of melanocyte-stimulating hormone receptor expression on normal human melanocytes: evidence for a regulatory role of ultraviolet B, interleukin-1alpha, interleukin-1beta, endothelin-1 and tumour necrosis factor-alpha.

Melanocyte-stimulating hormone (MSH) receptor binding activity and melanocortin-1 receptor (MC1-R) gene expression on normal human melanocytes have been studied as responses to the effects of ultraviolet B (UVB), interleukin-1 (IL-1), endothelin-1 (ET-1) and tumour necrosis factor-alpha (TNF-alpha), which are known as UV sensitive regulators of melanocytic function. MSH receptor (MSH-R) binding activity was upregulated by UVB, IL-1alpha, -1beta and ET-1, but was downregulated by TNF-alpha. Northern blot analysis showed that MC1-R mRNA expression was induced 24 h after UVB irradiation in a dose-dependent manner, and that 24-h treatment with ET-1 also induced an expression of MC1-R mRNA, whereas TNF-alpha downregulated the expression. In addition, IL-1alpha and -1beta have a small but real inductive effect on MC1-R mRNA expression. Taken together, our results suggest a model in which higher MC1-R mRNA expression is accompanied by upregulation of MSH-R binding activity, and enhanced by UVB or cytokines sensitive to UVB. Such a regulatory system would enable normal human melanocytes to respond to MSH more efficiently and induce an increase of melanization of the skin through the MSH/MSH-R system after UVB radiation.

Adolescent↗
PubMed1998

Effect of arbutin on melanogenic proteins in human melanocytes.

The inhibitory effect of arbutin, a naturally occurring beta-D-glucopyranoside derivative of hydroquinone, on melanogenesis was studied biochemically by using human melanocytes in culture. Cells were cultured in the presence of different concentrations of arbutin. The maximum concentration of arbutin that was not inhibitory to growth of the cells was 100 micrograms/ml. At that concentration, melanin synthesis was inhibited significantly by approximately 20% after 5 days, compared with untreated cells. This phenotypic change was associated with the inhibition of tyrosinase and DHICA polymerase activities, and the degree of inhibition was dose dependent. No significant difference in DOPAchrome tautomerase (DT) activity was observed before or after arbutin treatment. Western blotting experiments revealed there were no changes in protein content or in molecular size of tyrosinase, TRP-1 or TRP-2, indicating that inhibition of tyrosinase activity by arbutin might be due to effects at the post-translational level.

Adolescent↗
PubMed1997

Evidence for UV-associated activation of telomerase in human skin.

Telomerase activation plays a crucial role in the immortalization of human cells and carcinogenesis; however, the temporal and pathophysiological aspects of the activation in vivo are poorly understood. We found telomerase activity not only in malignant tumors (91%) but also in most benign (60%) and premalignant (89%) skin tumors. This suggests the involvement of telomerase activation in a crucial biological step of human skin carcinogenesis. Because UV light is a major factor in skin carcinogenesis, we further examined telomerase activity in normal skin samples and in normal skin samples adjacent to benign, premalignant, and malignant skin lesions. Data for chronically sun-exposed body sites were compared with those for covered sites. Among normal skin samples, 39% (26 of 67) had telomerase activity, and this activity was unrelated to neighboring lesions but strongly associated with the level of sun exposure. Fifty-four % (21 of 39) of normal skin samples from chronically sun-exposed sites were telomerase-positive, compared with only 12% (3 of 26) of samples from covered sites. When we examined telomerase activity and CC to TT mutations at codons 247/8 of the p53 gene (which are considered to be UV specific) in the same normal skin samples, only 43% (7 of 16) of telomerase-positive normal skin samples at sun-exposed sites contained the p53 mutations, whereas all (7 of 7) of the samples with UV-specific p53 mutations showed telomerase activity (P = 0.019). These data suggest that telomerase activation is involved at an early stage of human skin carcinogenesis and that activation may precede the acquisition of UV-associated p53 mutations in the skin. Telomerase activity was also found in plucked hair follicles and enzymatically separated epidermis, which may be associated with the presence of stem cells in the skin.

Enzyme Activation↗
PubMed1997

Incidence of actinic keratosis of Japanese in Kasai City, Hyogo.

We determined the incidence of actinic keratosis (AK) among Japanese by screening for skin cancer in Kasai City, Hyogo, Japan, between 1993 and 1995. The incidence per 100,000 Japanese residents was 223.6 in 1993 and 171.2 in 1994. The prevalence of AK was 291.2 per 100,000 residents in 1993, 203.7 in 1994, and 86.8 in 1995. The prevalence in people who had more than six seborrheic keratoses on sun-exposed body sites and in people who had experienced severe sunburns with blister formation during childhood were significantly higher. These results indicate that more than six seborrheic keratoses and several episodes of blister formation in childhood may be risk factors for AK in the Japanese.

Adult↗
PubMed1997

Prevalence of actinic keratosis in Japan.

Most of the epidemiological studies on skin cancer that have been conducted to date have addressed the incidence in light-skinned Caucasians. To determine the prevalence rate of skin cancer and actinic keratosis (AK) on sun-exposed body sites of Japanese in Japan, we examined the skin of 4736 people during health examinations. The study was undertaken in Kasai City, Japan, which had a population of 52,837 in 1992, where participants in a regional health examination were seen by dermatologists. The final diagnosis was made histopathologically. Participants were also interviewed by means of a questionnaire. A total of 36 cases of AK and two of basal cell carcinoma were identified, to give a prevalence of 413.4 per 100,000 for AK. The prevalence among outdoor workers was significantly higher than that of indoor workers. Furthermore, when the participants were classified into three Japanese skin types, the prevalence of AK among people of skin Type I, who are sensitive to UV irradiation, was significantly higher than that among people of skin Types II and III, who are less sensitive.

Adult↗
PubMed1997

Expression of fibroblast growth factor receptors in naevus-cell naevus and malignant melanoma.

In a previous study, we showed by immunohistochemical analysis that basic fibroblast growth factor (bFGF) is expressed strongly and homogeneously in naevus-cell naevus (NCN), while that in malignant melanoma (MM) is heterogeneous and sometimes non-existent. In order to elucidate the role of bFGF in these pigmented tumours, the expression of its receptors must be determined. In this study, we performed an immunohistochemical analysis of FGF receptors 1, 2 and 3 (FGFR-1, FGFR-2 and FGFR-3, respectively) in NCN and MM and compared their expression and localization with those of bFGF. The expression of bFGF and its three receptors was also examined in melanoma cell lines. None of the 10 NCN that showed strong, homogeneous staining for bFGF expressed FGFR-1 or FGFR-3 proteins; six weakly expressed FGFR-2 protein. Ten primary and 10 metastatic MM showed heterogeneous expression for the three receptors, with larger populations of FGFR-3-negative cells in the primary than in the metastatic tumours. Western blot analysis showed homogeneous expression of bFGF protein in all four melanoma cell lines tested, while FGFR proteins had a heterogeneous distribution in the different cell lines. Cultured NCN and normal melanocytes showed no immunoreactive band for FGFR-1 protein, the only protein tested. Our results suggested that tumour-derived bFGF is involved in melanoma formation through an autocrine mechanism, but is involved mostly through a paracrine or other mechanisms in NCN.

Blotting, Western↗
PubMed1997

Dermatomyofibroma (Plaqueförmige Dermale Fibromatose).

We reported a patient with dermatomyofibroma and reviewed the literature to characterize the immunohistochemical features of dermatomyofibroma. A 25-year-old woman presented with an asymptomatic, well-circumscribed, red-brown plaque on the left posterior shoulder. Microscopic examination revealed a non-encapsulated but well-circumscribed tumor in the mid-dermis extending into the upper subcutaneous fatty tissue. The tumor was composed of faintly eosinophilic, thin, wavy collagen fibers arranged as intersecting fascicles with an arrangement predominantly parallel to the skin surface. Embedded among the wavy fibers, there were a fair number of nuclei that were elongated, vesicular, and uniform in size. Immunohistochemical studies using a peroxidase-antiperoxidase technique disclosed that the cytoplasm of the tumor cells was positive for muscle actin. The tumor cells were negative for alpha-smooth muscle actin, desmin, factor XIIIa, S-100 protein, and CD34. Clinical, histopathologic, and immunohistochemical analysis confirmed dermatomyofibroma.

Actins↗
PubMed1997

Potential efficacy of low metal diets and dental metal elimination in the management of atopic dermatitis: an open clinical study.

We performed an open clinical study on the effects of low metal diets and/or dental metal elimination on 27 patients with moderate to severe atopic dermatitis (AD), who showed positive patch tests for metal allergens and/or clinical exacerbation by oral provocation tests with metal salts. All the patients were recommended to ingest low metal diets for 3 months and/or undergo dental metal elimination. Marked or moderate improvement was noted in 18 patients (67%); 7 patients (26%) showed marked improvement and 11 patients (41%), moderate improvement. Nine patients (33%) showed minimal improvement or no change. In the patients who showed marked or moderate improvement, we observed statistically significant decreases (p < 0.05) in both peripheral blood eosinophil counts and serum LDH levels after 3 months of treatment. The present study suggests that restriction of ingested metal allergens to which patients have positive patch tests and/or oral challenge tests may be useful in the management of some patients with AD who have metal sensitivity.

Administration, Oral↗
PubMed1997

Molecular genetic analysis of HLA class II alleles in Japanese patients with melanoma.

Distribution of HLA-DQA, -DQB and -DPB alleles in ninety-six Japanese patients with melanoma was analyzed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, and the association between clinical parameters and the presence of certain HLA class II alleles investigated. The frequency of HLA-DQB1*0302 was increased, while those of DQA1*0101(04), -DQA1*0401 and DRB1*0802 were decreased in melanoma patients compared with controls. Moreover, the frequency of HLA-DQA1*0103 in patients with acral lentiginous melanoma was increased compared with controls. However, none of these HLA class II alleles showed significant positive or negative associations after correction of the P value. In addition, there was no correlation between these antigens and clinical parameters. These results indicate that HLA class II alleles may not contribute to a strong susceptibility to melanoma in the Japanese.

Adult↗
PubMed1997

Less expression of cyclin E in cutaneous squamous cell carcinomas than in benign and premalignant keratinocytic lesions.

In a previous study, we showed that overexpression of cyclin D, a G1 cyclin, is frequently associated with keratinocyte carcinogenesis as an early event. Another G1 cyclin, cyclin E, was recently suggested to be a prognostic marker for breast cancer. In order to evaluate the role of cyclin E in human keratinocyte carcinogenesis, we analysed the expression of cyclin E by immunohistochemistry in normal skin, seborrheic keratosis (SK), keratoacanthoma (KA), actinic keratosis (AK), Bowen's disease (BD), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Positive cells were seen rarely in normal epidermis, in 9 of 20 cases of SK, in 5 of 6 cases of KA, in 9 of 13 cases of AK and in all 27 cases of BD. Some of the cases of AK and BD had positive cells in the superficial epidermis, where atypicality is less obvious. In contrast, positive cells were seen in 4 of 25 cases of SCC and none of 15 cases of BCC. These results suggest that expression of cyclin E plays a role in the formation of benign and premalignant keratinocytic tumors, whereas down-regulation of cyclin E expression may be involved in carcinogenesis in human keratinocytes.

Blotting, Western↗
PubMed1997

p21WAF1/CIP1 expression in non-melanoma skin tumors.

Abnormal control of the cell cycle is closely linked to carcinogenesis. p21WAF1/CIP1 protein is a universal inhibitor of G1 cyclin-dependent kinase and is induced by p53-dependent and -independent pathways. In order to elucidate the role of p21WAF1/CIP1 in human skin carcinogenesis, protein expression in squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Bowen's disease (BD), actinic keratosis (AK), keratoacanthoma (KA), seborrheic keratosis (SK), and normal skin was examined using an immunohistochemical method. In normal skin, a few positive cells were seen in some cases in the upper spinous layer of the epidermis; sebaceous glands also had positive cells. In cases of SK and KA, positive cells were found in the basal and suprabasal epidermal layers (proliferation pattern), and in cases of BD and AK, positive cells were seen mainly in the upper spinous layer (differentiation pattern). Cases of SCC had more positive cells and showed two staining patterns: proliferation, or mixed. Cases of BCC had no positive cells. p21WAF1/CIP1 has some unidentified role in keratinocyte tumorigenesis, which may not be related directly to carcinogenesis.

Antibodies↗