Search PubMed⌕ Search

Biomedical subjects

M J Cardosa

Publications and source records attributed to M J Cardosa.

28 records · Page 2Linked to original sources
PubMed1991

Dot enzyme immunoassay: an alternative diagnostic aid for dengue fever and dengue haemorrhagic fever.

A dot enzyme immunoassay (DEIA) for the detection of antibodies to dengue virus was tested for use as a tool in the presumptive diagnosis of dengue fever and dengue haemorrhagic fever. Paired sera from the following groups of patients were tested using the DEIA and the haemagglutination inhibition (HI) test: those with primary dengue fever; those experiencing a second dengue infection; and febrile patients who did not have dengue. The data obtained show that the DEIA can be effectively used at a serum dilution of 1:1000 to confirm presumptive recent dengue in patients with a second dengue infection. However, demonstration of seroconversion proved necessary for patients with primary dengue. At a serum dilution of 1:1000 the DEIA has a specificity of 97.3%. The role of this simple and rapid test in improving the effectivity of programmes for the control of dengue virus infection is discussed.

Adult↗
PubMed1988

Development of a dot enzyme immunoassay for dengue 3: a sensitive method for the detection of antidengue antibodies.

Partially purified DEN3 virus was used as antigen in a sensitive dot enzyme immunoassay (DEIA) for the detection of antibodies to flavivirus antigens. We describe here the method used to prepare and optimise the antigen-bearing nitrocellulose membranes and present the results obtained from screening 20 acute phase sera from patients shown to have had recent dengue infections by the haemagglutination inhibition (HI) test. Sixteen pairs of acute and convalescent sera from dengue-negative patients had no detectable antibody to dengue virus by HI. These were shown to have no antibody detectable by DEIA. Sera positive for dengue antibodies by HI had DEIA titers ranging from 10 to several thousand times greater than the titers detected by HI.

Antibodies, Viral↗
PubMed1988

A dot enzyme immunoassay for dengue 3 virus: comparison with the haemagglutination inhibition test.

A dot enzyme immunoassay (DEIA) was used to determine the levels of antibody to dengue 3 virus in the acute and convalescent sera of febrile patients with a clinical diagnosis of dengue fever or dengue haemorrhagic fever. The antibody titres were compared with titres determined by the haemagglutination inhibition (HI) test. The results of the study showed that, besides being more simple to perform, the DEIA is in order of magnitude more sensitive than the HI test. Furthermore, the data suggest that it is possible to use a single dilution as a cutoff point to predict with reasonable accuracy, if a patient has had a recent dengue infection. The DEIA test for antibodies to dengue virus is an appropriate technology highly suitable for rapid diagnosis and surveillance in developing countries.

Dengue↗
PubMed1986

Interaction of West Nile virus with primary murine macrophages: role of cell activation and receptors for antibody and complement.

We have measured growth of West Nile virus in mouse primary peritoneal macrophages (resident, thioglycolate elicited, and Mycobacterium bovis BCG activated) and in macrophagelike (P338D1) and nonmacrophage (L929, PS clone D) cell lines infected in the absence or presence of specific antibodies (immunoglobulin G ([IgG], IgM), and complement. Monoclonal antibodies directed against Fc receptors (IgG1/2b, 2.4G2) and type 3 complement receptors (Mac-1) were used to define the role of each receptor. Virus yield depended on a balance between enhancement and neutralization and was influenced by the physiologic state of the macrophage, the receptor pathway of viral entry, the mouse strain and age of donor. BCG-activated macrophages displayed a greater ability to restrict West Nile virus than nonactivated cells only in the presence of antiviral IgM, with or without complement; the Fc receptors for various classes of IgG mediated striking enhancement. These studies identify some of the complex innate and acquired factors that determine the interaction between West Nile virus and primary macrophages in vitro.

Age Factors↗
PubMed1983

Complement receptor mediates enhanced flavivirus replication in macrophages.

Evidence is presented that M phi complement receptors (CR3) mediate IgM-dependent enhancement of flavivirus replication in the presence of complement. Enhancement is blocked by pretreatment of macrophages with monoclonal antibody Ml/70, which inhibits CR3 binding, but not by pretreatment with monoclonal antibody 2.4G2, which inhibits FcR binding.

Animals↗
PubMed1979

Isolation and analysis of chemosensory behavior mutants in Drosophila melanogaster.

A behavioral countercurrent paradigm has been developed for assaying the chemotactic responses of wild-type and mutant Drosophila melanogaster adults. Oregon R males avoid both quinine sulfate and NaCl, whereas Oregon R females reject the quinine salt but are attracted to NaCl when tested in this paradigm. Wild-type behavior is sufficiently reproducible to allow identification of mutants affecting chemotaxis, and 12 such mutants, in six complementation groups, have now been isolated. Three of the mutants respond abnormally to NaCl, two in one complementation group with atactic behavior (no chemotaxis) and the other, in a separate group, with a mistactic response (attraction to the stimulus). Four mutants in another group respond mistactically to quinine sulfate. Of the remaining mutants, two in one group behave atactically and three, in two groups, respond mistactically to either chemical stimulus. Several of the mutants also show abnormal behavior in a proboscis extension assay when tested individually with sucrose solutions.

Animals↗