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A Ribera

Publications and source records attributed to A Ribera.

104 records · Page 6Linked to original sources
PubMed1976

Age differences in the positional distribution of phosphoglycerides and molecular species of choline phosphoglycerides during development of the chick embryo liver.

The total fatty acid composition and the distribution of acyl groups in the positions 1 and 2 of 1,2-diacyl-sn-glycero-3-phosphocholine and 1,2-diacyl-sn-glycero-3-phosphoethanolamine as well as in the molecular species of 1,2-diacyl-sn-glycero-3-phosphocholine from the chick embryo liver have been investigated at various stages of development. The fatty acid content of the main lipid classes from the yolks was also evaluated. The relative percentages of total saturated fatty acids in 1,2-diacyl-sn-glycero-3-phosphocholine remained constant during liver development; however, the levels of both main saturated acids, palmitic and stearic acids, were reciprocally counterbalanced as the age of the embryo proceeded. On the other hand, arachidonic acid decreased with time whereas linoleic acid and docosahexaenoic acid doubled their proportions during development. The relative amounts of total saturated fatty acids from liver 1,2-diacyl-sn-glycero-3-phosphoethanolamine were also constant during all stages of development; however, palmitic/stearic acid ratio did not change with time in this phosphoglyceride. Fatty acid composition of the yolk phosphoglycerides did not change during embryonic development. It should be noted that marked differences between fatty acid composition of choline and ethanolamine phosphoglycerides from the embryo liver and those of the yolk phosphoglycerides were demonstrated. The general patterns of the positional distribution of the acyl groups in choline phosphoglycerides differed from those of ethanolamine phosphoglycerides. Palmitic and stearic acids were only positioned at position 1 in 1,2-diacyl-sn-glycero-3-phosphoethanolamine whereas both fatty acids did not acylate exclusively the position 1 in 1,2-diacyl-sn-glycero-3-phosphocholine.

Animals↗
PubMedDate not supplied

Antibody elution from red blood cells by chloroform and trichloroethylene.

Antibody elution by chloroform and trichloroethylene was compared with the Rubin ether method modified by Hughes-Jones for IgG antibodies and the Landsteiner and Miller heat method for IgM antibodies. After washing the cells, the chloroform and trichloroethylene method was done at 37 degrees C for 10 minutes. With this technique the eluate remained on the upper layer above the red blood cell stroma layer, while with Rubin's method the eluate remained below the cell stroma. The reported technique was as effective as the Landsteiner and Miller heat method for IgM antibodies, and a double volume of eluate was obtained.

Blood Group Antigens↗
PubMedDate not supplied

Disulphide bonds are a requirement for adsorption of cephalosporins on the red cell membrane.

The authors studied the behavior of red cells (RBCs), treated with 2-aminoethylisothiouronium bromide (AET), against 100 serums containing cephalothin antibodies and 27 serums with cephapirin antibodies. None of the serums reacted with cephalosporin-coated RBCs that had been exposed previously to AET. The possibility of the Kell system acting as a receptor for cephalosporins was excluded. The authors discuss the significance of cysteine disulphide bonds and the tertiary or quaternary structure of red cell membrane proteins in the binding of cephalosporins to RBCs.

Adsorption↗
PubMedDate not supplied

[Evaluation of various tests for the detection of antigen and antibodies in the diagnosis of primary HIV infection].

The effectiveness of different methodologies to identify antigenemia and antibodies against HIV at the time of viral primary infection was evaluated. To this end, 6 consecutive serum samples of a patient who had had symptomatic seroconversion were assessed. The detection of antigenemia was earlier than that of antibodies, although the sensitivity of the three evaluated assays varied greatly. An enzyme immunoassay (EIA) designed with synthetic peptides from the HIV envelope (third generation EIA) was the most sensitive test for antibody detection. Five other tests elaborated with antigenic material from a viral lysate (first generation) or with recombinant proteins (second generation) were reactive later, although the second generation EIA were more sensitive. A rapid immunofiltration test (HIV-Check) had good sensitivity, similar to that of the second generation EIA. Western blotting (WB) identified antibodies against the viral core later than the third generation EIA, and all the bands required for the diagnosis only appeared three weeks later. Therefore, although WB is an excellent method to confirm results from other tests, it may not be definitive for the results at the primary infection period when other particularly sensitive techniques are already diagnostic. We think that the higher sensitivity of EIA tests using synthetic peptides justifies its generalization for sample screening in blood banks.

AIDS Serodiagnosis↗