Oxidation markedly reduces bilirubin interference in the Jaffe creatinine assay.
(65/612)
Bilirubin causes underestimation of serum creatinine in the Jaffe alkaline picrate assay. We report an approach for preventing bilirubin interference by pretreating serum samples with peroxidase and H2O2. The dissociation of bilirubin from albumin and its subsequent oxidation markedly reduces the bilirubin interference and enables accurate determination of creatinine concentrations by the Jaffe reaction even in hyperbilirubinemic sera. Within-run CVs were 2.6%, 4.0%, and 3.8% at mean creatinine concentrations of 88, 165, and 349 mumol/L, respectively (n = 20). Day-to-day CVs were 4.0%, 6.3%, and 5.8% for mean creatinine concentrations of 87, 168, and 364 mumol/L, respectively (n = 12). Average recovery of creatinine added to serum in the presence of 600 mumol/L bilirubin was 97% (n = 15). This method requires only small serum volumes (70 microL) and is easily applicable to automated analyzers that can be programmed to add three reagents consecutively. (+info)
Immunological mechanisms in the reaction between drugs and the skin.
(66/612)
Many reactions in the skin caused by drugs would appear to be due to immunological mechanisms. Simple chemical sensitizers become antigenic after combination with carrier proteins. The bonds between the hapten and the protein are not necessarily covalent, and it is likely that weaker linkages such as hydrogen bonding or Van der Waal's forces may be involved. Reactions may be due to humoral antibody or cell-mediated immunity. Experimental models are discussed in which there is competition between B suppressor cells and T effector cells. In these situations, drugs that affect the suppressor cell system specifically can reverse a state of immunological tolerance or increase the intensity of a chemical sensitivity. Finally, the mechanism of fixed drug eruptions is discussed. It is suggested that the actions which follow the systemic absorption of the chemical and always occur at this same site are due to B cells or B cell products that remain from a previous delayed hypersensitivity reaction to the same antigen. These cells would have arrived initially as part of the non-specific inflammatory infiltrate. The initial reaction may even have been subliminal in intensity. (+info)
IMMUNOLOGICAL UNRESPONSIVENESS TO SENSITIZATION WITH SIMPLE CHEMICAL COMPOUNDS; A SEARCH FOR ANTIBODY-ABSORBING DEPOTS OF ALLERGEN.
(67/612)
Guinea pigs fed picryl chloride to induce specific immunologic unresponsiveness cleared small amounts of venously infused antipicryl antibody at a rate equal to that of normal guinea pigs. Catabolism of passively administered picryl-specific antibody did not alter the unresponsive state of picryl chloride-fed guinea pigs or the responsive state of normal guinea pigs. Lymphoid cells of picryl chloride immunized guinea pigs produced equal amounts of picryl-specific antibody in picryl chloride-fed and normal animals. Allergen-fed guinea pigs remained unresponsive to attempted sensitization with the allergen in excess of 10 months after the final feeding, though some became feebly sensitive between 9 and 11 months. Second attempts to make unresponsive animals hypersensitive were unsuccessful. White blood cells of guinea pigs unresponsive to picryl chloride were unable to transfer delayed-type hypersensitivity for picryl chloride to normal recipients yet readily transferred tuberculin hypersensitivity. (+info)
IN VITRO STUDIES OF CELLULAR HYPERSENSITIVITY. II. RELATIONSHIP OF DELAYED HYPERSENSITIVITY AND INHIBITION OF CELL MIGRATION BY PICRYLATED PROTEINS.
(68/612)
Some characteristics of inhibition of cell migration induced in tissue culture by the addition of specific antigen were studied. The following characteristics were found to be shared by this type of cellular hypersensitivity and delayed cutaneous sensitivity: 1. Specificity for the carrier moiety of haptene protein conjugates. The picryl protein conjugate used to sensitize guinea pigs inhibited migration of monocytic cells from these animals. Other picrylated proteins produced little inhibition. 2. Enhancement by mycobacterial adjuvants. Incorporation of tubercle bacilli with picrylated proteins in adjuvant-antigen emulsions stimulated the development of this cellular hypersensitivity to antigen. 3. Independence of circulating antibody. In contrast to cellular hypersensitivity, serum antibody (a) reacted with any of a number of picrylated proteins, (b) developed well in the absence of mycobacterial adjuvant, and (c) persisted in unchanged titer for 5 weeks in animals sensitized with saline solutions of antigen. During this time cellular hypersensitivity decreased remarkably. The in vitro system described provides a direct method to measure cell-antigen interaction and permits study of an aspect of the immune response not mediated by humoral antibody. The relation of cellular hypersensitivity to antibody formation and delayed hypersensitivity is discussed. (+info)
Initial hydrogenation during catabolism of picric acid by Rhodococcus erythropolis HL 24-2.
(69/612)
Rhodococcus erythropolis HL 24-2, which was originally isolated as a 2,4-dinitrophenol-degrading bacterium, could also utilize picric acid as a nitrogen source after spontaneous mutation. During growth, the mutant HL PM-1 transiently accumulated an orange-red metabolite, which was identified as a hydride-Meisenheimer complex of picric acid. This complex was formed as the initial metabolite and further converted with concomitant liberation of nitrite. 2,4,6-Trinitrocyclohexanone was identified as a dead-end metabolite of the degradation of picric acid, indicating the addition of two hydride ions to picric acid. (+info)
Synthesis and biological activity of sulfur-containing aryl-aldehyde Schiff bases.
(70/612)
A series of chemically modified aryl-aldehyde Schiff bases has been synthesized and tested for their antioxidant activity and radiation protection. We observed that disulfide-containing aryl-aldehyde Schiff base 6c exhibited potent free radical scavenging, antioxidation, and radioprotection activities. (+info)
A new naphthopyrone from the root of Pleuropterus ciliinervis.
(71/612)
A new naphthopyrone, pleuropyrone A (1), together with (-)-lyoniresinol 3a-O-beta-D-glucopyranoside (2) and (+)-lyoniresinol 3a-O-beta-D-glucopyranoside (3) was isolated from the roots of Pleuropterus ciliinervis. The structure of pleuropyrone A (1) was determined to be 2,5-dimethyl-8-hydroxynaphthopyrone 10-O-beta-D-glucopyranoside by spectroscopic methods including 2D-NMR. Compounds 2 and 3 showed moderate antioxidant activity. (+info)
Screening chemical composition and in vitro antioxidant and antimicrobial activities of the essential oils from Origanum syriacum L. growing in Turkey.
(72/612)
In the present study, essential oil from the leaves of Syrian oreganum [Origanum syriacum L. (Lauraceae)] grown in Turkish state forests of the Dortyol district, Turkey, was obtained by steam distillation. The chemical composition of oil was analysed by GC and GC-MS, and was found to contain 49.02% monoterpenes, 36.60% oxygenated monoterpenes and 12.59% sesquiterpenes. The major components are as follows: gamma-terpinene, carvacrol, p-cymene and beta-caryophyllene. Subsequently, the reducing power, antioxidant and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activities of the essential oil were studied. The reducing power was compared with ascorbic acid, and the other activities were compared with 2,6-di-tert-butyl-4-methyl phenol (BHT, butylated hydroxytoluene). The results showed that the activities were concentration dependent. The antioxidant activities of the oil were slightly lower than those of ascorbic acid or BHT, so the oil can be considered an effective natural antioxidant. Antimicrobial activities of the essential oil from the leaves of Origanum syriacum was also determined on 16 microorganisms tested using the agar-disc diffusion method, and showed antimicrobial activity against 13 of these. (+info)