Nineteen male workers from a factory making lead batteries participated in monthly blood tests to follow the effects of decreasing exposures to lead. The overall average blood lead (B Pb) concentration was 1.95 mumol/l (40 micrograms/100 ml), but a significant decrease was seen over the one year study period. The relation to erythrocyte zinc-protoporphyrin (ZPP) concentration showed considerabl...

A micromethod for detecting and determining various porphyrins extracted from biological materials, especially nervous tissues (I), is needed. The technique of filter paper chromatography by Consden, Gordon, and Martin (a), with modification by Williams and Kirby’s capillary ascent (3), has been applied to the problem in this study. The recent paper by Nicholas and Rimington (4) on partition ch...

Most existing theoretical models of photodynamic therapy (PDT) assume a uniform initial distribution of the photosensitive molecule, Protoporphyrin IX (PpIX). This is an adequate assumption when the prodrug is systematically administered; however for topical PDT this is no longer a valid assumption. Topical application and subsequent diffusion of the prodrug results in an inhomogeneous distribu...

Protoporphyrin IX ferrochelatase (EC 4.99.1.1) catalyzes the terminal step in the heme biosynthetic pathway, the insertion of ferrous iron into protoporphyrin IX. Ferrochelatase shows specificity, in vitro, for multiple metal ion substrates and exhibits substrate inhibition in the case of zinc, copper, cobalt, and nickel. Zinc is the most biologically significant of these; when iron is depleted...

Protoporphyrinogen oxidase (Protox) catalyses the oxidation of protoporphyrinogen IX to protoporphyrin IX during the synthesis of tetrapyrrole molecules. Protox is encoded by the hemY gene in eukaryotes and by the hemG gene in many γ-proteobacteria, including Escherichia coli. It has been suggested that other bacteria possess a yet unidentified type of Protox. To identify a unique bacterial gen...

In extension of two previous series of experiments, the results of which have been partially reported (1), further long-term tests were performed with daily oral doses of 5 mg Pb++ in 2 subjects. Lead in whole blood, free protoporphyrin 9 (III) and 5-aminolevulinate dehydratase activity in erythrocytes, hemoglobin, and urinary 5-aminolevulinic acid and coproporphyrin III excretion values were m...

We describe results of a 3-year study in which 499 paired venous and capillary blood specimens, collected by fingerstick on the same day, were analyzed for lead (BPb) and erythrocyte protoporphyrin (EP). False-positive rates (FPRs) and the proportion of false positives were calculated at four BPb thresholds. At the 100 microg/L threshold, the FPR for all data was 13%, but the proportion of fals...

Light-absorption spectra of complexes between reduced iron-protoporphyrin IX (2 X 10-S M) and various polylysine samples (up to 2 X 1OW residue molar) were measured in the range 380-630 rnp in deaerated aqueous solutions of pH 12 and at 27”. The absorption spectra obtained were very similar to well-known ferrohemochrome spectra of proteins or of complexes of protoheme with low-molecular-weight ...