The resolution of membrane proteins based upon size, charge, and hydrophobicity

Currently available systems for resolving membrane proteins are based only on size and charge differences. Recently, it has been shown that Triton-urea-acetic acid gels which separate proteins on the basis of charge, size and hydrophobicity are capable of resolving proteins differing only by the substitution of a single neutral amino acid. We have applied this new method to the resolution of bacterial envelope proteins. Conditions for optimal resolution of different bacterial envelope proteins were determined by electrophoresis through transverse urea and Triton X-100 gradient gels. We have also correlated the components resolved in this system with those resolved by classical sodium dodecyl sulfate-gel electrophoresis by using two-dimensional slab gels combining the two systems. Furthermore, envelope protein fractions from different species and strains of bacteria were compared to identify specific proteins. This system appears to be a promising method for investigating envelope proteins which are due to missense mutations.     

Cross-sectional assessment of ELISA reactivity in leprosy patients, contacts, and normal population using the semisynthetic antigen natural disaccharide octyl bovine serum albumin (ND-O-BSA) in Cebu, The Philippines

An indirect enzyme-linked immunosorbent assay (ELISA) using natural disaccharide octyl bovine serum albumin (ND-O-BSA) as antigen was used in testing leprosy patients, contacts and a normal population in Cebu, The Philippines, from 1985 to 1989. A total of 1413 persons were studied. The results suggested that ELISA reactivity and the bacterial index (BI) correlate in a general way. In multibacillary (MB) leprosy, positivity ranges from 54.2% to 92.3% among patients with a BI of < 2+ to > 4+ on the Ridley scale, with an overall average of 84.5%. Paucibacillary (PB) leprosy patients have a low degree of reactivity, with only 15.0% ELISA positive. The test is more efficient in detecting MB than PB leprosy. The contacts of MB leprosy showed 6.5% positivity; contacts of PB leprosy, 7.0% positivity. The normal population showed 1.7% positive ELISA or 17 per thousand population, which is very much less than that of the household contacts. However, because the normal population is a much larger population than the household contact population in a community, more new leprosy cases would emanate from it. Leprosy workers are concerned about the transmission of the disease to household contacts. However, for the reason stated above, we should be more concerned with the silent spread of the disease to the normal population in the community.(ABSTRACT TRUNCATED AT 250 WORDS)     

Idiopathic duro-optic calcification--a new entity?

This is a report of two patients with intracranial dural and optic nerve/sheath calcification. CT and MR features of this previously unreported condition are illustrated.     

The origin of the hydroxyl radical oxygen in the Fenton reaction

There is an ongoing discussion in the chemical literature regarding the nature of the highly reactive hydroxyl radical formed from the reaction between ferrous iron and hydrogen peroxide (the Fenton reaction). However, the fundamental experiment of directly determining the source of the hydroxyl radicals formed in the reaction has not yet been carried out. In this study, we have used both hydrogen peroxide and water labeled with 17O, together with ESR spin trapping, to detect the hydroxyl radicals formed in the reaction. ESR experiments were run in phosphate buffer with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap, and either H2O2 or H2O labeled with 17O. The hydroxyl radical was generated by addition of Fe2+ ion to H2O2, or as a control, by photolysis of H2O2 in the ESR cavity. Observed ESR spectra were the sum of DMPO/.16OH and DMPO/.17OH radical adduct spectra. Within experimental accuracy, the percentage of 17O-labeled hydroxyl radical trapped by the DMPO was the same as in the original hydrogen peroxide, for either method of hydroxyl radical generation, indicating that the trapped hydroxyl radical was derived exclusively from hydrogen peroxide and that there was no exchange of oxygen atoms between H2O2 and solvent water. Likewise, the complementary reaction with ordinary H2O2 and 17O-labeled water also showed that none of the hydroxyl radical was derived from water. Our results do not preclude the ferryl intermediate, [Fe = O]2+ reacting with DMPO to form DMPO/.OH if the ferryl oxygen is derived from H2O2 rather than from a water ligand.