Ultraviolet B (UVB) alters the expression of heat shock protein 70 (HSP70) in cultured fibroblast cells derived from human skin. However, the nature of the signal transduction pathway remains to be determined. Transforming growth factor-beta (TGF-beta) has a large variety of biological functions, including cell growth control, modulation of inflammation and immunoregulation. In this study, we examined whether TGF-beta is associated with the process of HSP70 expression induced by UVB irradiation. The constitutive expression of TGF-beta1 mRNA and HSP70 expression in human skin fibroblast cells were detected using reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. The results indicate that: (1) UVB irradiation stimulates HSP70 expression in a dose- and time-dependent manner, (2) constitutive expression of TGF-beta1 mRNA is detected after UVB irradiation, the level of which peaks at 4 h after 10 mJ cm-2 of UVB irradiation, (3) HSP70 expression is induced by TGF-beta1 without UVB irradiation, and (4) HSP70 expression induction with UVB irradiation is inhibited by preincubation of the cells with the anti-TGF-beta type II receptor antibody. Our results suggest that HSP70 expression induced by UVB involves the autocrine signalling of TGF-beta production.

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The local influence of three clothing materials i.e. silk, cotton and nylon, in (1) full or (2) partial skin contact or (3) at 3 mm from the skin, on sweat evaporation from the chest skin surface of human subjects was studied. The hygrometer-ventilated capsule method was used and sweating was induced at ambient thermoneutrality by a central heat load following lower-leg immersion in water at 43 degrees C. The presence of clothing delayed the rise in capsule relative humidity (CRH) induced by heat loading. During the first 6 min of heating, CRH rose more steeply with clothing that was in full skin contact than with clothing that had partial or no contact. The rate of decrease in CRH from 1 min to 6 min after heating was not influenced by the presence of clothing or by the different degrees of skin contact. The subsequent return of CRH to the pre-heating level was delayed most by cotton, less by silk and least by nylon. For silk and nylon, partial contact with the skin prolonged the return to control conditions, as compared with full skin contact.

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