PubMed Health⌕ Search

Biomedical subjects

J Pal

Publications and source records attributed to J Pal.

10 recordsLinked to original sources
PubMed1998

Influence of chemical modification of cysteine and histidine side chains upon subunit reassembly of alpha crystallin.

Alpha crystallin, the important multimeric structural protein of mammalian eye lens, is an assembly composed of 30 alpha-A and 10 alpha-B subunits. The influence of either partial or complete chemical modification of two important amino acid side chains, cysteine and histidine, upon the integrity of native alpha crystallin assembly and also upon the mode of subunit reassembly has been investigated. It has been found that chemical modification of surface-exposed cysteine and histidine side chains does not affect the subunit-subunit interactions stabilizing the native aggregate. Cysteine modifications, either partial or complete, unlike histidine modifications, do not seem to affect the backbone conformation of the subunits refolded after denaturation. Both cysteine and histidine modifications, however, affect the packing of the refolded structural elements forming the tertiary structure of the subunits and also the mode of oligomeric reorganization. The most striking effect of histidine modification is the considerable increase in size of the aggregates upon reassociation of the modified subunits. The chaperone activity, however, has been found to remain almost unaffected in spite of these chemical modifications.

Chromatography, Gel↗
PubMed1998

The effect of glutathione upon chaperone activity of alpha-crystallin is probably mediated through target modulation.

We studied the effect of the presence of glutathione, both reduced (GSH) and oxidized (GSSG), on the chaperone activity of alpha-crystallin towards thermal aggregation of gamma 2-crystallin. Results showed that while GSH enhanced the chaperone activity of alpha-crystallin, GSSG appeared to diminish it to some extent. When, however, the effect of the presence of glutathione was studied in the absence of alpha-crystallin, the nature of their action was found to be almost similar to that observed in its presence. These results suggest that glutathiones probably modulate the target protein which ultimately influences the chaperone activity of alpha-crystallin.

Animals↗
PubMed1997

Chemical modifications and dissociation characteristics of tyrosine and tryptophan residues in alpha-crystallin.

A quantitative estimation of surface accessibility of aromatic residues in alpha-crystallin from goat lens has been accomplished by chemical modifications using different specific reagents having varying sizes. Results of modification of tyrosine residues with N-acetylimidazole and tetranitromethane when combined with those of ionization studies carried out with hydroxyl ions having the smallest size reveal different classes of tyrosine residues in the native protein: 78 +/- 2 residues have been found to be easily available for modification; among the rest, 94 +/- 2 residues appear to be comparatively less exposed to the reagents while 28 +/- 2 residues are found to be completely unavailable for modification in the native protein and are modified only when the protein is denatured. Modification of tryptophan residues with H2O2 also indicates different classes of these residues available for oxidation at different concentrations of the oxidant. 34 +/- 2 residues of tryptophan are found to be easily oxidized at a lower concentration of H2O2 during the first phase of the reaction. The remaining tryptophan residues appear to be less exposed to the reagent. This is also corroborated from the studies of reactivities of these residues towards another specific but bulkier reagent, 2-hydroxy-5-nitrobenzyl bromide. These surface exposed aromatic residues in alpha-crystallin may be considered to be vulnerable to in vivo oxidative modifications forming insoluble aggregates which may finally contribute to the formation of cataract.

Crystallins↗
PubMed1989

The value of the Glasgow Coma Scale and Injury Severity Score: predicting outcome in multiple trauma patients with head injury.

This retrospective study of multiple trauma patients requiring SICU admission was undertaken to determine to what extent, if any, head injury affected patient outcome. One hundred seventy such patients with head injuries had further analysis. Glasgow Coma Scale (GCS) values at approximately 5 hours postinjury were evaluated, and the Glasgow Outcome Scale was determined 1 month postinjury. A good recovery was seen in 99% of the 87 patients with GCS 15-13. This fell to 71% of the 24 patients with GCS 12-9. Among 59 patients having a GCS below 9, 41% died and an additional 17% had a poor recovery, leaving only 35% with an eventual good outcome. By using both Injury Severity Score and GCS at 6 hours postinjury, physicians will be more accurate in assessing outcome of multiple trauma patients with head injuries.

Adolescent↗
PubMed1983

Immunochemical studies on Shigella dysenteriae type 9 bacterial polysaccharide.

On graded hydrolysis and Smith degradation, the O-somatic polysaccharide isolated from Shigella dysenteriae type 9 bacteria, strain NCTC 7919, yielded five oligosaccharides which were characterized. The positions of the O-acetyl and pyruvic acetal groups in the repeating unit were identified. Immunochemical studies indicated that D-galactose is the immunodominant sugar in the polysaccharide, and one of the oligomers, having the structure Gal-(1 leads to 3)-GlcNAc-(1 leads to 3)-Gal-(1 leads to 4)-Man, showed maximum inhibition of the homologous precipitation.

Antigen-Antibody Complex↗
PubMed1983

Immunochemical studies on a polysaccharide from Shigella dysenteriae type 2.

The polysaccharide isolated from Shigella dysenteriae type 2, strain NCTC 566, on Smith degradation and graded hydrolysis yielded three oligosaccharides which were characterised using methylation studies. Using homologous rabbit antiserum and the monosaccharides that constituted the polysaccharide and the oligosaccharides isolated from it and the cross-reactions in some type-specific pneumococcal antisera, immunochemical specificities of different sugar groupings in the polysaccharide molecule were determined. These results indicated that N-acetylglucosamine was the immunodominant sugar in the polysaccharide and the oligosaccharide isolated from the Smith-degraded product and having the structure (formula; see text) gave maximum inhibition of the specific precipitation.

Chemical Phenomena↗
PubMed1976

Lingual abscess.

Explore the source record for details and available documents.

Abscess↗