silicon and Dermatitis

We generated low-flux X-ray micro-planar beams (MPBs) using a laboratory-scale industrial X-ray generator (60 kV/20 mA) with custom-made collimators with three different peak/pitch widths (50/200 μm, 100/400 μm, 50/400 μm). To evaluate normal skin reactions, the thighs of C3H/HeN mice were exposed to 100 and 200 Gy MPBs in comparison with broad beams (20, 30, 40, 50, 60 Gy). Antitumor effects of MPBs were evaluated in C3H/HeN mice with subcutaneous tumors (SCCVII). After the tumors were irradiated with 100 and 200 Gy MPBs and 20 and 30 Gy broad beams, the tumor sizes were measured and survival analyses were performed. In addition, the tumors were excised and immunohistochemically examined to detect γ-H2AX, ki67 and CD34. It was shown that antitumor effects of 200 Gy MPBs at 50/200 μm and 100/400 μm were significantly greater than those of 20 Gy broad beams, and were comparable with 30 Gy broad beams. γ-H2AX-positive cells demonstrated clear stripe-patterns after MPB irradiation; the pattern gradually faded and intermixed over 24 h. The chronological changes in ki67 positivity did not differ between MPBs and broad beams, whereas the CD34-positive area decreased significantly more in MPBs than in broad beams. In addition, it was shown that skin injury after MPB irradiation was significantly milder when compared with broad-beam irradiation at equivalent doses for achieving the same tumor control effect. Bystander effect and tumor vessel injury may be the mechanism contributing to the efficacy of MPBs.

Topics: Animals; Antigens, CD34; Bystander Effect; Carcinoma, Squamous Cell; Dermatitis; Dose-Response Relationship, Radiation; Equipment Design; Immunohistochemistry; Ki-67 Antigen; Mice; Mice, Inbred C3H; Neoplasm Transplantation; Neoplasms; Radiation Injuries; Radiometry; Silicon; Skin; Time Factors; X-Rays

Several lines of transgenic mice with gangliosides GM2/GD2 synthase gene were established, and the expression levels of the transgene in brain, liver, spleen and thymus were analyzed by comparing with those in their litter mates. Among four tissues, brain and skin showed markedly high expression levels of the transgene in Northern blotting. Particularly, transgenic mice skin showed about 10-fold higher expression of GM2/GD2 synthase gene than the wild type mice skin. Therefore, alterations in the morphology, glycolipid components, and responses to the exogenous stimulations in the transgenic mice skin were examined. Gangliosides in the transgenic skin were dramatically converted from GM3 to GM1, whereas no morphological changes were observed. However, when skin flap test was performed with insertion of nylon membranes under the skin flaps, much stronger inflammatory reactions consisting of edema, marked thickness, and cell infiltration were observed in the transgenic mice compared with the wild type. Similar enhanced inflammatory reaction was also observed in the skin injected by silicon gel, and in the peritoneal reaction to the injected casein. Main cell population in these inflammatory reactions consisted of neutrophils, suggesting an increased sensitivity of neutrophils to chemotactic factors in the transgenic mice.

Topics: Animals; Brain; Dermatitis; Gangliosides; Gene Expression; Genetic Engineering; Mice; Mice, Transgenic; N-Acetylgalactosaminyltransferases; Neutrophils; Organ Specificity; Polypeptide N-acetylgalactosaminyltransferase; RNA, Messenger; Silicon; Skin; Superoxides; Surgical Flaps

Topics: Animals; Anti-Infective Agents, Local; Arsenic; Dermatitis; Female; Magnesium; Male; Mycoses; Rotenone; Sheep; Sheep Diseases; Silicon; Sulfates; Sulfur; Zinc

Topics: Child; Dermatitis; Dermatitis, Contact; Hexachlorophene; Humans; Infant; Infant Care; Powders; Silicon; Urea

Topics: Child; Dermatitis; Dermatitis, Contact; Diaper Rash; Hexachlorophene; Humans; Infant; Occupations; Ointments; Silicon; Urea

Topics: Cyclopentanes; Dermatitis; Dermatitis, Contact; Humans; Hypnotics and Sedatives; Parasympatholytics; Silicon; Sulfanilamide; Sulfanilamides; Sulfonamides; Sympathomimetics

Topics: Aerosols; Dermatitis; Dermatitis, Contact; Resins, Plant; Resins, Synthetic; Silicon; Silicones; Skin Diseases

Topics: Biomedical Research; Dairy Products; Dermatitis; Dermatitis, Contact; Humans; Occupational Health; Silicon; Silicones

Topics: Buffers; Dermatitis; Dermatitis, Contact; Ointments; Silicon; Silicones

Topics: Biomedical Research; Dermatitis; Dermatitis, Contact; Humans; Silicon; Silicones; Skin

Topics: Biomedical Research; Dairy Products; Dermatitis; Dermatitis, Contact; Humans; Silicon; Silicones

Topics: Dermatitis; Dermatitis, Contact; Dermatitis, Occupational; Humans; Silicon

Topics: Dermatitis; Dermatitis, Contact; Humans; Industry; Laboratories; Silicon; Silicones

Topics: Biomedical Research; Dermatitis; Dermatitis, Contact; Humans; Silicon; Silicones

Topics: Dermatitis; Dermatitis, Contact; Detergents; Glass; Humans; Silicon; Water

Topics: Allergens; Biomedical Research; Collodion; Dermatitis; Dermatitis, Contact; Humans; Silicon; Silicones