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W Cardoso

Publications and source records attributed to W Cardoso.

8 recordsLinked to original sources
PubMed1990

Screening for antibodies against infectious bronchitis virus: specificity of the haemagglutination inhibition test.

A screening of antibodies against strain M-41 and the Dutch variant strains D-274 and D-1466 of infectious bronchitis virus (IBV) using the haemagglutination inhibition test (HI) was carried out in Chile. The presence of these variant strains has not been reported yet and therefore the probability of finding positive flocks is low. On this basis some statistical analysis were made with those data obtained in order to contribute to the problem of the specificity of the HI test for IBV diagnosis. All sera were distributed in different categories of possible results against each strain according with the HI titre obtained and employing different discrimination levels for a positive or negative status against IBV. It was concluded that discrimination levels varying from 4.0 to 5.0 log2 are useful for establishing the presence or absence of antibodies against IBV but if a serotype specific diagnosis is needed, then the discrimination level should be elevated, specially when secondary immune responses are measured.

Animals↗
PubMed1975

Relation between the amount of smooth muscle of venous tissue and the degree of supersensitivity to isoprenaline caused by inhibition of catechol-O-methyl transferase.

The relation between the smooth muscle cell mass of dog saphenous vein strips and the degree of supersensitivity to isoprenaline caused by U-0521 (3,4-dihydroxy-2-methyl propiophenone), an inhibitor of the catechol-O-methyl transferase (COMT), was studied. For the quantitative determination of smooth muscle mass, the thickness of the muscle layer as determined by light microscopy and the maximal shortening induced by supramaximal concentration of phenylephrine were used. After the strips had been contracted by 3x10-6M phenylephrine, a concentration which was able to produce an about 90% maximal contraction, dose-response curves to the relaxant effect of isoprenaline were determined in the absence and in the presence of U-0521 (10-4M). It was observed that U-0521 caused marked supersensitivity to the relaxant effect of isoprenaline (varying between 3 and 81 times), as well as an increase of the maximal relaxation caused by this amine (varying between 7 and 120%). The correlation between these data and the smooth muscle cell mass shows that there was a direct proportionality between these parameters. Oxytetracycline (10-4M), an inhibitor of binding of catecholamines to collagen, did not produce any enhancement of the effects of isoprenaline. It is concluded that COMT is related to smooth muscle cells in this tissue.

Animals↗