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Biomedical subjects

A Ishibashi

Publications and source records attributed to A Ishibashi.

At least 19 recordsLinked to original sources
PubMed2001

Trp122 and Trp134 on the surface of the catalytic domain are essential for crystalline chitin hydrolysis by Bacillus circulans chitinase A1.

From the 3D-structural analysis of the catalytic domain of chitinase A1, two exposed tryptophan residues (W122 and W134) are proposed to play an important role in guiding a chitin chain into the catalytic cleft during the crystalline chitin hydrolysis. Mutation of either W122 or W134 to alanine significantly reduced the hydrolyzing activity against highly crystalline beta-chitin microfibrils. Double mutation almost completely abolished the hydrolyzing activity. On the other hand, the hydrolyzing activity against either soluble or amorphous substrate was not reduced. These mutations slightly impaired the binding activity of this enzyme. These results clearly demonstrated that the two exposed aromatic residues play a critical role in hydrolyzing the chitin chain in crystalline chitin.

Bacillus↗
PubMed2001

Immunohistochemical detection of lipid peroxidation products, protein-bound acrolein and 4-hydroxynonenal protein adducts, in actinic elastosis of photodamaged skin.

Acrolein and 4-hydroxy-2-nonenal (HNE) are both byproducts of a lipid peroxidation reaction. Actinic elastosis in photodamaged skin of aged individuals is characterized by the accumulation of fragmented elastic fibers in the sun-exposed areas. To study whether a lipid peroxidation reaction is involved in the accumulation of altered elastic fibers in actinic elastosis, skin specimens obtained from sun-damaged areas were immunohistochemically examined using the antibodies against acrolein and HNE. Both antibodies were found to react with the accumulations of elastic material. Double immunofluorescence labeling demonstrated that acrolein/elastin and HNE/elastin were colocalized in the actinic elastosis. Western blot analysis showed that the polypeptide with a molecular weight of 62 kDa reacted with anti-acrolein, anti-HNE and anti-elastin antibodies. The results suggest that acrolein and HNE may be associated with actinic elastosis.

Acrolein↗
PubMed2001

In vitro and in vivo expression of protoporphyrin IX induced by lipophilic 5-aminolevulinic acid derivatives.

We estimated the expression level of protoporphyrin IX (PpIX) induced by lipophilic 5-aminolevulinic acid (ALA) derivatives and observed its histological distribution by fluorescence microscopy. In vitro PpIX expression in Hepe2 cells was the highest when induced by ALA pentyl ester. This level was 2.8-fold higher than that induced by ALA after 4 h incubation and 2.5-fold higher than that after 24 h incubation. The differences between ALA pentyl ester and ALA were significant at both time points (P<0.01). In HeLa cells, ALA butyl ester showed the highest induction of PpIX, which was 2.6-fold higher than ALA after 4 h incubation and 3.5-fold higher after 24 h incubation. The differences were significant at both time points (P<0.01). In mice with squamous cell carcinoma, the in vivo expression of PpIX in the tumors was highest with ALA methyl ester, which was 1.3-fold higher than ALA. The difference was significant (P<0.01). The expression of PpIX by means of fluorescence microscopy was highest by ALA methyl ester. Under in vitro conditions, PpIX expression was efficiently induced by long chain ALA esters, while better in vivo PpIX induction was obtained with short chain ALA esters. In this study, ALA methyl ester was found to be the best among the ALA derivatives in inducing PpIX expression in vivo, and would be more effective in treatment of skin cancers than ALA.

Aminolevulinic Acid↗
PubMed2001

Photodynamic therapy of acne vulgaris with topical delta-aminolaevulinic acid and incoherent light in Japanese patients.

BACKGROUND: Photodynamic therapy (PDT) is useful for treatment of epidermal neoplasia but may also have a role in the treatment of inflammatory dermatoses. OBJECTIVES: To study the effect of PDT in patients with acne. METHODS: Three men and 10 women who suffered from intractable acne vulgaris were treated using PDT with topical delta-aminolaevulinic acid (ALA) and polychromatic visible light. Twenty per cent ALA in an oil-in-water emulsion was applied to the lesions for 4 h with a light-shielding dressing. The lesions were then exposed to polychromatic visible light at 600-700 nm using a halogen light source of energy intensity 17 mW cm-2 and a total energy dose of 13 J cm-2. RESULTS: All patients had apparent improvement of facial appearance and reduction of new acne lesions at 1, 3 and 6 months following PDT treatment. The adverse effects were discomfort, burning and stinging during irradiation, oedematous erythema for 3 days after PDT, epidermal exfoliation from the fourth to the 10th day, irritation and hypersensitivity to physical stimulation for 10 days after PDT, and pigmentation or erythema after epidermal exfoliation; the treated lesions returned to normal skin conditions within 1 month. CONCLUSIONS: PDT was beneficial in the treatment of acne. As a photoactivating light source, polychromatic visible light was thought to be better for use with acne patients than laser light because of its cost-effectiveness, uniform illumination and time-efficiency in treating large areas.

Acne Vulgaris↗
PubMed2001

Reticular erythematous mucinosis syndrome with an infiltration of factor XIIIa+ and hyaluronan synthase 2+ dermal dendrocytes.

We report a patient with reticular erythematous mucinosis (REM) syndrome. Content of hyaluronan in lesional skin was approximately 2.9-fold higher than in the patient's uninvolved skin, but its synthetic activity in fibroblasts explanted from lesional skin remained unchanged. Immunohistochemical study using antifactor XIIIa (anti-FXIIIa) antibody demonstrated that the number of FXIIIa+ cells in the lesional skin was significantly increased compared with those in the patient's uninvolved skin and in normal control skin samples (P < 0.01). As hyaluronan is considered to be synthesized by hyaluronan synthase (HAS), which is composed of three genetically distinct isoforms (HAS1, HAS2 and HAS3), the cells responsible for the accumulation of hyaluronan in lesional skin were immunohistochemically examined using antibodies for HAS1, HAS2 and HAS3. The specific antibody for HAS2 was found to react with some populations of FXIIIa+ cells in the involved skin, and the number of HAS2+ cells was significantly increased in the involved skin (P < 0.01). The results suggest that accumulation of hyaluronan in REM may be related to populations of FXIIIa+/HAS2+ dermal dendrocytes rather than to dermal fibroblasts.

Cell Culture Techniques↗
PubMed2001

Effects of suplatast tosilate on airway inflammation and airway hyperresponsiveness.

Suplatast tosilate (IPD) is a Th2 cytokine inhibitor that lowers the titer of the IgE antibody through specific inhibition of the production of IL (interleukin)-4 and IL-5 by T cells and inhibits tissue infiltration by eosinophils. In this clinical trial, suplatast tosilate (300 mg/day) was administered orally for 4 weeks to 25 patients (13 patients with atopic asthma, 12 patients with nonatopic asthma) whose bronchial asthma was staged in step 1 or step 2 according to the Guidelines for Prevention and Management of Bronchial Asthma, 1998. Before and after administration, the parameters of airway inflammation, that is, peripheral blood eosinophils count, serum level of eosinophil cationic protein (ECP), ECP level in induced sputum, airway hyperresponsiveness (Dmin), and morning peak expiratory flow (PEF), were measured. The peripheral blood eosinophil count, serum level of ECP, and ECP level in induced sputum decreased significantly. Of these parameters, the ECP level in induced sputum was the most sensitive. Furthermore, suplatast tosilate significantly inhibited Dmin. These results were especially significant in patients with atopic asthma. Suplatast tosilate was considered to have inhibited airway eosinophilic inflammation through decreases in peripheral blood eosinophils counts and in ECP levels in induced sputum, which resulted in inhibition of airway hyperresponsiveness.

Adult↗
PubMed2001

The needs of children and adolescents with cancer for information and social support.

Research has indicated that information and social support may have helped children and adolescents with cancer to cope with their illness and lead normal lives. However, recent researchers have reported that youths with cancer express a clear interest in receiving more information and social support. This study reviewed research on information and social support for children and adolescents with cancer to understand their needs. Young patients with cancer showed high uncertainty about cancer. Besides, adolescents with cancer were more in conflict with their parents than healthy youths. Discussions on future plans or death are difficult for young people with cancer. They also are frequently absent from school over time. Moreover, they want to make healthy friends. To fulfill the needs of these youths, nurses should be aware not only of individualized information and social support, but also of these factors from an ecologic perspective. Further qualitative research is required to identify the needs of youths with cancer and resolve these issues.

Adolescent↗
PubMed2001

Existence of retinoic acid-receptor-independent retinoid X-receptor-dependent pathway in myeloid cell function.

We previously reported that ER-27191 (4-[4,5,7,8,9,10-hexahydro-7,7,10,10-tetramethyl-1-(3-pyridylmethyl)anthra[1,2-b]pyrrol-3-yl]benzoic acid) is a potent antagonist of retinoic acid receptor (RAR), and ER-35795 ((2E,4E,6E)-7-[1-(1-methylethyl)-8-chloro-1,2,3,4-tetrahydroquinolin-6-yl]-6-fluoro-3-methyl-2,4,6-nonatrienoic acid) is a novel retinoid X receptor (RXR)-specific agonist. By using these compounds, we investigated whether distinct RAR-dependent and RXR-dependent pathways operate to mediate the diverse activities of retinoids, particularly, the effects of the RXR pathway on cellular function. ER-27191 completely antagonized HL60 cell differentiation induced by all-trans-retinoic acid (atRA). However, the differentiation induced by the ER-35795 was not antagonized at all by the RAR antagonist, but was inhibited by an RXR homodimer antagonist (LGD100754, (2E,4E,6Z)-7-(3-n-propoxy-5,6,7,8-tetrahydro-5,5,8,8-tetramethylnaphthalen-2-yl)-3-methylocta-2,4,6-trienoic acid). Its agonistic action on RXR/RAR heterodimer, on the other hand, was neutralized by the RAR antagonist. During HL60 cell differentiation, atRA induced RARbeta mRNA, while the RXR had no effect. Interestingly, a functional RXR-pathway was also seen in lipopolysaccharide-induced inhibition of mouse splenocyte proliferation. These results strongly suggest the existence of a pharmacological RXR-dependent pathway that is activated by a ligand that can bind to RXR.

Animals↗
PubMed2000

Expression of type XVI collagen in cultured skin fibroblasts is related to cell growth arrest.

The expression of type XVI collagen in various phases of cell growth in cultured skin fibroblasts was studied. A marked increase in type XVI collagen mRNA level was found in stationary phases of cell growth (non-adherent and confluent phases), whereas the expression of type I and III collagens was undetectable in the non-adherent phase but became greater in the confluent phase. When suspended cells were further cultured over 72 h (suspension arrest), mRNA level and gene transcription of type XVI collagen were time-dependently increased whereas those of type I collagen remained undetectable. When the confluent cells were further cultured for 72 h under the condition of serum deprivation (serum deprivation arrest), mRNA levels of both type XVI collagen and type I collagen were elevated. The level of type XVI collagen polypeptide in the culture media of suspension-arrested and serum deprivation-arrested cells paralleled the mRNA level of type XVI collagen. The results indicate that expression of type XVI collagen (a member of the fibril-associated collagens with interrupted triple helices), unlike interstitial collagens (type I collagen), is related to cell growth arrest brought about by two different growth inhibiting systems, suspension arrest and serum deprivation arrest.

Cell Adhesion↗
PubMed2000

Expression of microfibril-associated glycoprotein-1 (MAGP-1) in human epidermal keratinocytes.

Microfibril-associated glycoprotein (MAGP) is a major structural component of connective tissue microfibrils. We studied the expression of MAGP-1 in cultured human keratinocytes and its modulation during Ca(++)-induced differentiation. RT-PCR and Western blot assays demonstrated the presence of mRNA and the polypeptide of MAGP-1 in cultured keratinocytes. MAGP-1 mRNA levels in cultured keratinocytes during Ca(++)-induced differentiation were enhanced eightfold with a concomitant increase in involucrin (a marker of terminal differentiation) mRNA levels. Double immunofluorescence labeling of cultured keratinocytes demonstrated that both anti-MAGP-1 and anti-involucrin antibodies reacted with the identical cells. The population of MAGP-1-producing cells in cultured keratinocytes significantly increased during Ca(++)-induced differentiation. These results indicate that MAGP-1 expressed by cultured keratinocytes reaches maximum levels at the stage of terminal differentiation in vitro. Double immunostaining of normal human skin with anti-MAGP-1 and anti-elastin antibodies demonstrated the colocalization of MAGP-1-positive and elastin-positive fibers in the superficial and mid-dermis. MAGP-1 produced by keratinocytes may play some functional role in the formation of dermal matrix organization in the dermis.

Calcium Chloride↗
PubMed2000

Expression of elastin-related proteins and matrix metalloproteinases in actinic elastosis of sun-damaged skin.

Actinic elastosis is characterized by an accumulation of elastotic material in the upper dermis and is considered to be a manifestation of ultraviolet-induced skin aging. To compare the structural components of the elastotic material in actinic elastosis with those in normal skin, skin specimens were stained with antibodies raised against various elastin-related proteins. Elastotic materials exhibited a strong reaction to the antibodies for elastin, microfibril-associated glycoprotein-1 (MAGP-1), MAGP-4, matrix metalloproteinase 1 (MMP-1), MMP-2 and MMP-3, but a diminished reaction to anti-MMP-9 antibody. Fibroblast cell lines from the upper dermis of affected and unaffected skin were established, and the mRNA levels of MMPs were determined. MMP-1 and -2 mRNA levels were found to be elevated approximately twofold in the fibroblasts from actinic elastosis. Since MMP-1 and -2 are considered to be major enzymes involved in the degradation of matrix components, the accumulation of elastotic materials in actinic elastosis may be related to the degradation process.

Aged↗
PubMed2000

Elafin is induced in epidermis in skin disorders with dermal neutrophilic infiltration: interleukin-1 beta and tumour necrosis factor-alpha stimulate its secretion in vitro.

BACKGROUND: Elafin, an elastase inhibitor produced by keratinocytes, is overexpressed in the subcorneal region of skin affected by psoriasis, a major feature of which is epidermal infiltration by neutrophil leucocytes. OBJECTIVES: We studied the expression of elafin in the epidermis in other skin disorders characterized by dermal neutrophil infiltration and in skin disorders with dermal lymphocyte infiltration. PATIENTS/METHODS: We examined biopsies from the lesional skin of patients with Behçet's syndrome, Sweet's syndrome, pyoderma gangrenosum, cutaneous allergic vasculitis and acute bacterial infection (cellulitis), and from the skin of patients with chronic prurigo, discoid lupus erythematosus and psoriasis. We performed in vitro experiments using cultured keratinocytes treated with mediators such as interleukin (IL)-1 beta, tumour necrosis factor (TNF)-alpha, IL-6, neutrophil elastase and interferon (IFN)-gamma. RESULTS: Anti-elafin antibody showed a strong reaction with the subcorneal region of the epidermis in patients with Behçet's syndrome, Sweet's syndrome, pyoderma gangrenosum, cutaneous allergic vasculitis and acute bacterial infection (cellulitis), but showed no reaction in skin from patients with dermal lymphocyte infiltration such as is seen in chronic prurigo and discoid lupus erythematosus. The in vitro experiments demonstrated that treatment with IL-1 beta and TNF-alpha resulted in 2.6-fold and 4-fold stimulation of elafin secretion, respectively, whereas IL-6, neutrophil elastase and IFN-gamma caused no significant changes in elafin release. CONCLUSIONS: These results suggest that inflammatory mediators such as IL-1 beta or TNF-alpha secreted by dermal neutrophils may be involved in overexpression of elafin in keratinocytes; this could protect the epidermis from degradation by dermal neutrophil infiltration.

Cell Culture Techniques↗
PubMed2000

Elastin peptides induce migration and terminal differentiation of cultured keratinocytes via 67 kDa elastin receptor in vitro: 67 kDa elastin receptor is expressed in the keratinocytes eliminating elastic materials in elastosis perforans serpiginosa.

To delineate the molecular mechanism of transepidermal elimination of dermal elastic materials in elastosis perforans serpiginosa, the interaction between elastin and cultured keratinocytes was studied in vitro. Synthetic elastin peptide VGVAPG elicited chemotactic responses to the cultured keratinocytes at the dose of 10-9 M. Treatment of keratinocytes with 10-6 or 10-5 M elastin peptides resulted in the suppression of cell growth and the increased expression of involucrin and transglutaminase-1, markers of terminal differentiation. When cultured keratinocytes were treated with the elastin peptides, the expression of 67 kDa elastin receptor was increased. The induction of terminal differentiation by elastin peptides was attenuated by the treatment with the combination of anti-67 kDa elastin receptor antibody. The results indicate that elastin is a potent inducer of migration and terminal differentiation of cultured keratinocytes, which is mediated by the 67 kDa elastin receptor. In the lesional skins of patients with elastosis perforans serpiginosa, the 67 kDa elastin receptor was specifically expressed in the epidermis immediately surrounding the elastic materials that were being eliminated. The elastin receptor may be involved in the interaction between keratinocytes and elastin in elastosis perforans serpiginosa.

Cell Differentiation↗