Identification and partial characterisation of a serum enzyme which hydrolyses epidermal inhibitory pentapeptide.

We have identified an enzyme present in mammalian, avian, and reptilian serum which cleaves epidermal inhibitory pentapeptide (pGlu-Glu-Asp-Ser-GlyOH) to form a relatively stable tripeptide (pGlu-Glu-Asp). The enzyme has an inhibitor profile unlike any readily identifiable serum enzyme, and is stable at 4 degrees C for up to 3 months. As most experiments using the pentapeptide are carried out in the presence of serum this finding may have important implications on future research into the biological function of the pentapeptide.

Type VII collagen is a normal component of epidermal basement membrane, which shows altered expression in recessive dystrophic epidermolysis bullosa.

The murine monoclonal antibody LH 7:2, which reacts with the basement membrane of stratified squamous epithelia including epidermis, has been characterized biochemically and shown to bind to part of the type VII collagen molecule. Immunoblotting reveals that the antibody binding site lies in the non-helical carboxy terminal region of the type VII collagen dimer and immunoelectron microscopy shows that the epitope is within the lamina densa of the basement membrane. Loss of LH 7:2 binding in the hereditary blistering disease recessive dystrophic epidermolysis bullosa suggests that inadequate synthesis or excessive breakdown of type VII collagen may form the biologic basis for the disease.

A study of the health of Malaysian plantation workers with particular reference to paraquat spraymen.

Tests of pulmonary function (FVC, FEV1, FEV 1%, and single breath CO diffusion), renal function (serum creatinine and BUN), liver function (serum ALT, AST, and ALKP) and a full haematological screen were performed on 27 paraquat spraymen (mean spraying time 5.3 years; mean individual annual quantity of paraquat handled, 67.2 kg as paraquat ion) and on two control groups. One of the control groups consisted of 24 general plantation workers with minimal exposure to paraquat arising from occasional work in recently sprayed areas, and the second consisted of 23 latex factory workers with no known occupational exposure to paraquat. The results showed no significant differences as a consequence of occupational exposure to paraquat. Long-term paraquat spraying at the concentrations used produced to quantifiable harmful effects on health as measured by the indices selected for this study.