Browsing by Author "QUIROGA, T"

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    DIAGNOSIS OF TYPHOID-FEVER BY 2 SEROLOGIC METHODS - ENZYME-LINKED-IMMUNOSORBENT-ASSAY OF ANTILIPOPOLYSACCHARIDE OF SALMONELLA-TYPHI ANTIBODIES AND WIDAL TEST
    (1992) QUIROGA, T; GOYCOOLEA, M; TAGLE, R; GONZALEZ, F; RODRIGUEZ, L; VILLARROEL, L
    Serum samples from 85 patients with proven typhoid fever, 11 patients with p-typhoidal fever, 101 patients with febrile non-typhoidal, and 130 healthy subjects were tested for immunoglobulin G (IgG), IgA, and IgM antilipopolysaccharide (LPS) of Salmonella typhi antibodies by enzyme-linked immunosorbent assay (ELISA) and Widal test. The levels of all three classes of immunoglobulin anti-LPS of S. typhi were higher in typhoid patients than in healthy or febrile nontyphoidal groups; we selected various combinations between the three classes of immunoglobulin to obtain the best combination of sensitivity and specificity. The sum of the absorbance values obtained from the ELISA assay for IgG + IgA + IgM (SIGMAlgs) was the best choice for diagnostic utility for typhoid fever. We selected a positive test at a decision level of SIGMAlgs greater-than-or-equal-to 1.2 with a sensitivity of 94% and a specificity of 92% with a frequency of false negative of 5.9%. The frequency of false positives for healthy controls was 7.7% and, for the febrile nontyphoidal group, it was 7.9%. We also compared receiver (or relative) operating characteristic (ROC) curves for the diagnostic usefulness of the ELISA with that of the Widal test, whose merits and limitations, especially in endemic regions, are discussed. The ELISA assay was much more sensitive and specific than any combination of the Widal test, and hence it could be a useful tool for the serologic diagnosis of typhoidal fever with a single blood sample.
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    HLA-ANTIGEN EXPRESSION AND PANEL REACTIVE ANTIBODIES
    (APPLETON & LANGE, 1995) RODRIGUEZ, L; CALDUMBIDE, I; MARTINEZ, L; SCAGLIOTTI, P; QUIROGA, T
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    MEASUREMENT OF PLEURAL FLUID CHOLESTEROL AND LACTATE-DEHYDROGENASE - A SIMPLE AND ACCURATE SET OF INDICATORS FOR SEPARATING EXUDATES FROM TRANSUDATES
    (1995) COSTA, M; QUIROGA, T; CRUZ, E
    Objectives: To evaluate the usefulness of diverse combinations of pleural cholesterol concentration, pleural or serum protein, and lactate dehydrogenase (LDH) levels for the differentiation of pleural exudates and transudates.
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    TOTAL SIALIC-ACID IN HUMAN AND CANINE PLATELETS DOES NOT CHANGE WITH THE PLATELET AGE
    (WILEY-LISS, 1992) MEZZANO, D; ARANDA, E; GARCIA, ME; PEREIRA, J; QUIROGA, T; PEREZ, M
    Total platelet sialic acid (SA) was measured in three experimental conditions: (1) human and canine platelet density subpopulations obtained by centrifugation in arabinogalactan gradients, (2) circulating canine platelets during recovery from experimental immune and mechanical thrombocytopenias, and (3) platelets obtained from a patient with chronic immune thrombocytopenic purpura before and after splenectomy. The density of human and canine platelets is, in part, determined by their age. We found no significant differences in total SA between high-density (HD) and low-density (LD) platelets (9.32 +/- 2.0 vs. 9.55 +/- 1.3-mu-g/mg of platelet protein in dogs and 9.02 +/- 2.3 vs. 9.10 +/- 2.9 mu-g/mg in humans). In the human and canine thrombocytopenic models, the entrance of new platelets from the bone marrow is followed by their aging in the circulation. In these models, no significant changes in total SA content were detected in sequential measurements during the recovery of the thrombocytopenia. Accordingly, we conclude that total SA in human and canine platelets is unrelated to their age in circulation. These results do not support the notion that the loss of SA from membrane glycoproteins determines the recognition and removal of platelets from the circulation.