Sweat lead levels in persons with high blood lead levels: experimental elevation of blood lead by ingestion of lead chloride.

Blood lead levels were experimentally elevated in two subjects by ingestion of single oral doses of lead as lead chloride. Serial samples of blood, urine and sweat were collected subsequently. Sweat samples were collected in polythene armbags while subjects cycled on a bicycle ergometer in a hot chamber. In spite of increases in blood and urinary lead levels, no increases in sweat lead levels were recorded. Possible reasons for this observation are discussed.

Lead in sweat and its relationship to salivary and urinary levels in normal healthy subjects.

Sweat was collected from the arms of 24 normal healthy subjects while they sat in a hot chamber. Blood, urine and saliva samples were also collected. These were analyzed for lead by atomic absorption spectrophotometry. Sweat lead levels recorded in this study are lower than those previously reported. Subjects with mean blood lead levels of 8.62 micrograms dl-1 (range 6-13.6) had mean sweat levels of 5.2 micrograms l-1 (range 1.5-13.0), approximately 25% of their urinary levels. Although salivary lead levels with a mean of 4.8 micrograms l-1 (range 2.5-10) are comparable to sweat levels, their relationship to blood lead levels is poor (r = -0.186 compared with r values of 0.7208 and 0.234 for sweat and urinary levels, respectively).

Lipopolysaccharide-free Escherichia coli OmpF and Pseudomonas aeruginosa protein P porins are functionally active in lipid bilayer membranes.

Escherichia coli porin OmpF and Pseudomonas aeruginosa porin protein P were eluted from sodium dodecyl sulfate-polyacrylamide gels. The resultant porin preparations were found to be devoid of detectable lipopolysaccharide (LPS) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining for LPS, direct enzyme-linked immunosorbent assays with LPS-specific monoclonal antibodies, and 2-keto-3-deoxyoctulosonic acid assays. The average conductances, ionic selectivities and incorporation rates of the electroeluted porins were identical to those of their conventionally purified counterparts. These data suggest that LPS is not required per se for porin function.

Outer membrane protein NmpC of Escherichia coli: pore-forming properties in black lipid bilayers.

The purified NmpC outer membrane protein from Escherichia coli, when incorporated into planar lipid bilayers, gave rise to channels with a single-channel conductance of 1.8 nS in 1 M KCl. This suggests that the NmpC protein is a porin.

Measurement of the clothing ventilation index.

In order to achieve thermal comfort while wearing protective clothing, heat loss from the body by convection and by the evaporation of sweat must be readily controlled by the wearer's thermoregulatory system. This can only be achieved if air is flowing through the clothing micro-environment in sufficient quantity to remove sensible and insensible heat as required. The volume flow of air through the clothing assembly is therefore an important determinant of thermal comfort. This paper describes a new procedure for estimating under working conditions, the volume of air flowing through the micro-environment. The method is based on two techniques: the first gives a measure of the volume of the micro-environment; the other uses a trace gas to measure the rate of air exchange. Algebraic combination of the results enables the air exchange characteristics of a garment to be described in terms of a Ventilation Index. It is proposed that this index be used to describe the performance of protective clothing assemblies.