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Biomedical subjects

B Astorga

Publications and source records attributed to B Astorga.

17 recordsLinked to original sources
PubMed1995

[External quality control of the parasitological diagnosis of Cryptosporidium parvum].

Between 1991 and 1994, eight external quality assessments of Cryptosporidium parvum infection diagnosis were performed. Stool specimens were sent to 74 laboratories, to be stained and examined. In 40 laboratories (54.1%), the diagnosis was correct in all evaluations, whereas in 34 (46%), the diagnosis disagreed with the parasitology reference laboratory in one occasion or more. The mean correlation of diagnoses with the reference laboratory was 88% (range 79-96%). Ninety-three percent of negative samples and 87% of positive samples were correctly diagnosed. These figures are similar to those obtained abroad. These results lead to the development of a quality control network for the diagnosis of Cryptosporidium parvum infections along the country, aiming to improve its reliability.

Animals↗
PubMed1993

[Cryptosporidium parvum in patients with chronic diarrhea and AIDS: diagnosis by means of indirect immunofluorescence with monoclonal antibodies].

The diagnosis of cryptosporidiosis is difficult when oocyst elimination is poor as occurs in AIDS patients. Aiming to improve the diagnosis, 144 fecal samples coming from AIDS patients with diarrhea, were studied using indirect immunofluorescence with anti-Cryptosporidium monoclonal antibodies. The results were compared with Ziehl Neelsen and safranine stainings. Twenty three samples (15.9%) were positive for Cryptosporidium with at least one of the three methods. Sensitivities were 78.3% for immunofluorescence, 86.9% for Ziehl Neelsen and 91.3 for safranine stainings. The specificity of the three methods was 100%. It is concluded that immunofluorescence does not improve the diagnostic accuracy of cryptosporidiosis and its high cost precludes its use in routine laboratories.

AIDS-Related Opportunistic Infections↗
PubMed1991

[Indirect immunofluorescence with monoclonal antibodies in the diagnosis of Pneumocystis carinii. Preliminary report].

We compared traditional methods based on argentic metamine and toluidine blue staining vs recently introduce techniques based on immunofluorescence for monoclonal antibodies in the diagnosis of P. carinii. Fifty samples were analyzed: 29 (58%) were negative by all method. Of the remaining 21.72% were positive for immunofluorescence, 67% for argentic and 48% for toluidine blue staining. Thus, immunofluorescence techniques represent an improvement in the ability to diagnose infection by P carinii.

Acquired Immunodeficiency Syndrome↗
PubMed1990

[Chagas' disease: an evaluation of serodiagnosis at blood banks in the endemic areas of Chile].

Blood transfusion is one mechanism leading to transmission of Chagas disease. An evaluation of the serologic method used to survey donors in 55 blood banks located in endemic areas was attempted. From 47 responders, 29 (62%) showed complete correlation with the standard used, 16 (34%) showed only 50% correlation and 2 were not possible to evaluate. Most errors were due to an incorrect evaluation of the negative standard serum, whereas the positive one was correctly diagnosed as such in 96% of cases.

Blood Banks↗
PubMed1990

[Commercial reagents in the diagnosis of Chagas' disease].

The great diversity of commercially available products for the serologic diagnosis of Chagas disease led us to conduct a study of these products in comparison with the indirect immunofluorescence test. Percent agreement between methods ranged from 79 to 100%, the details for each product being given in the text. Better control of commercially available diagnostic products is recommended.

Chagas Disease↗
PubMed1989

Hydatidosis diagnosis by double diffusion in agar with arc 5 detection.

To further assess the double diffusion arc 5 (DD5) test for human hydatidosis, the test was performed on sera from 45 patients with surgically confirmed hydatidosis and 54 with other pathologies in Santiago, Chile. Combined with tests reported previously, this brought the total number of study subjects with confirmed hydatidosis to 98 and the total with other pathologies to 128. Overall, the test yielded positive results with sera from 55 (56%) of the 98 serologically confirmed cases, the degree of seropositivity among patients with pulmonary hydatidosis (36%) being relatively low. The criteria adopted for a positive result were the presence of arc 5 or, in the absence of arc 5, the presence of three or more bands of precipitate. On the basis of these criteria, no false positive results were detected using sera from the 128 patients with other pathologies. It is concluded that using the DD5 test to diagnose hydatidosis in clinically selected individuals can provide results of high specificity; i.e., positive results can be taken as confirming presence of the infection. On the other hand, a negative DD5 result does not constitute definite proof that no hydatid cysts are present.

Adolescent↗