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Biomedical subjects

M C Bernal

Publications and source records attributed to M C Bernal.

26 records · Page 2Linked to original sources
PubMed1992

[Quantification of the levels of p24 antigen and antibodies in human immunodeficiency virus infection].

BACKGROUND: Quantification and clinical evaluation of p24 antigen and anti-HIV antibody levels. METHODS: Follow up of 13 HIV infected patients (53 sera) by determination of p24 antigen, total anti-HIV antibodies, anti-p24 and anti-env antibodies by ELISA and their semiquantitation. IgG and IgM class antibody determination by immunoblot techniques. RESULTS: The highest levels of p24 have been found in WR 1 and WR 6 stages. Commonly accepted serologic pattern has not been found in 100% of our cases. Western-blot is more sensitive for the detection of anti-p24 antibodies. CONCLUSIONS: p24 antigen appearance and a decrease in anti-p24 antibody level is related to a worse clinical prognosis. p24 antigen quantification is a usefull test for monitoring AZT therapy in patients suffering from AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Evaluation of the pre-S (pre-S(1)Ag/pre-S(2)Ab) system in hepatitis B virus infection.

The diagnostic and prognostic value of pre-S(1)Ag and pre-S(2)Ab was investigated in 69 HBsAg surface antigen positive patients--14 with acute hepatitis B, 30 with chronic liver disease (six chronic persistent hepatitis, 14 chronic active hepatitis, 10 with cirrhosis) and in 25 asymptomatic carriers. Pre-S(1)Ag was found in all patients with chronic hepatitis B virus (HBV) infection regardless of viral replication. In contrast, pre-S(2)Ab was not detected in any patients. Acute hepatitis was studied sequentially with periodic controls at 20 day intervals. Pre-S(1)Ag cleared before HBsAg in six of 14 (43%) patients who progressed favourably, and the two antigens cleared simultaneously in eight of 14 (57%) cases. Patients with early clearance of pre-S(1)Ag progressed favourably, thus indicating the prognostic value of this test, which, however, is still of limited practical application given the small temporal difference between the moment of clearance of the two antigens. The first markers to clear, however, were HBeAg and DNA-HBV, which showed significant differences with respect to the clearance of HBsAg. Moreover, pre-S(2)Ab appeared before HBsAb in 57.1% of our patients and was found in some patients before pre-S(1)Ag and HBsAg had cleared (42.8%), thus allowing complete viral clearance and acute HBV infection to be predicted earlier.

Biomarkers↗
PubMed1991

A study of different parameters of cell-mediated immunity in patients with active and chronic tuberculosis.

A study was carried out on cell-mediated immunity in healthy persons and patients with tuberculosis in order to extend the diagnostic capacity in tuberculosis. We studied the relation between baciloscopy and the state of specific cell-mediated immunity in vivo (Mantoux) and in vitro (leukocyte migration inhibition assay with PPD-RT 23 to evaluate specific cell-mediated immunity and PHA to evaluate nonspecific immunity) in 131 patients with active tuberculosis, in 63 patients with chronic tuberculosis, in 62 healthy persons and 10 individuals living with tuberculosis patients. The results demonstrate that the percentage of reaction was very low in both tests, being of no statistical significance the difference between patients with active or with chronic tuberculosis, although it was significant in the control group. In about half of the patients with active tuberculosis a positive baciloscopy could be observed; the percentage was much lower in patients suffering from chronic tuberculosis, the difference between the two groups significant from a statistical point of view. At the same time when we carried out an evolutionary study in 10 patients with positive baciloscopy, we observed a slight capacity of conversion of immunity when the baciloscopy was negative.

Adolescent↗
PubMed1988

A study of the evolution of specific and non-specific immune complexes in acute hepatitis B and chronic hepatitis.

Circulating immune complexes (ICs) containing IgG and HBsAg, and IgG and HBeAg, in sera from groups of patients with various liver diseases were sought by ELISA and immunodiffusion. A correlation was found between the absence of ICs and the disappearance of HBsAg in patients who had recovered from acute hepatitis B, but complexes containing HBsAg were always found in chronic hepatitis.

Antigen-Antibody Complex↗
PubMedDate not supplied

A seroepidemiological study of human immunodeficiency virus infection in northeast Zaire.

To evaluate the incidence of human immunodeficiency virus type 2 infections in an endemic African area, we have studied 134 patients from Northeast Zaire. Sera were tested for HIV-1 and HIV-2 antibodies to asses cross-reactivity or a possible double infection. Sixty five (48.5%) serum samples were reactive for HIV-1 and six (4.5%) for HIV-2 using specific Western blots. The enzyme immunoassays used to detect HIV-2 showed cross-reactivity with HIV-1 in 17 samples (16.5%). Tests based upon synthetic peptides corresponding to specific from human immunodeficiency viruses confirm their ability to discriminate antibodies directed against both viruses in 42/47 samples (89.4%); in 5/47 (10.6%) this test could not distinguish double infection from cross-reactivity. We suggest that the high number of sexual partners may be responsible for HIV transmission in our study group.

AIDS Serodiagnosis↗
PubMedDate not supplied

Immune complex p24 antigen: a new prognostic marker in human immunodeficiency virus infection.

p24 antigen (p24 Ag) is usually not found in patients in the asymptomatic phase of HIV infection, mainly because it is bound to anti-p24 antibodies (p24 Ab), with which it forms immune complexes. Nine asymptomatic patients positive for HIV-1 antibodies (stage II CDC criteria) treated with r alpha-interferon were followed (7.5 +/- 0.5 months), and a basal and final sample were tested for p24 Ag immune complexes (p24 Ag-IC), free p24 Ag, p24 Ab, CD4 count, beta 2-microglobulin, properdin B factor, and C3 and C4 complement fractions. p24 Ag-IC was detected in 55.5% of the samples, whereas free p24 Ag was detected in 5.5%. The finding of no change or an increase in p24 Ag-IC serum levels may be considered a prognostic marker. We believe that p24 Ab cannot be used as a prognostic marker unless p24 Ag-IC detection is simultaneously evaluated.

Antigen-Antibody Complex↗