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Biomedical subjects

R Esteban

Publications and source records attributed to R Esteban.

At least 163 records · Page 9Linked to original sources
PubMed1987

Anti-HD IgM as a marker of chronic delta infection.

The value of anti-HD IgM as a marker of chronic delta infection was evaluated by correlating its presence in serum with that of HD-Ag in liver cells and with the degree of inflammatory activity. Thirty-six patients with HBsAg-positive chronic hepatitis and anti-HD at high titers were studied. Overall, the liver cells of 26 patients contained HD-Ag and 27 were positive for IgM anti-HD. The correlation between both markers was excellent: 25 cases were positive for both serum anti-HD IgM and intrahepatic HD-Ag and 8 were negative for both markers. There was only 1 HD-Ag-positive patient, who was anti-HD IgM-negative. Two patients were anti-HD IgM-positive and HD-Ag-negative. Histological damage was more severe in anti-HD IgM-positive cases than in those negative for this marker (Knodell's index 13.5 vs 11.9, P less than 0.01). We conclude that anti-HD IgM is a good marker of chronic active delta infection.

Adolescent↗
PubMed1987

A new non-mendelian genetic element of yeast that increases cytopathology produced by M1 double-stranded RNA in ski strains.

The Saccharomyces cerevisiae SKI (superkiller) genes are repressors of replication of M, L-A, and L-BC double-stranded (ds) RNAs; ski strains have an increased M dsRNA copy number and, as a result, are cold-sensitive for growth at 8 degrees. Growth is normal, however, at higher temperatures. We have found a new cytoplasmic genetic element [D] (for disease) that makes M1 dsRNA-containing superkiller strains grow slowly at 30 degrees, not at all at 37 degrees, and only very poorly at 20 degrees. These growth defects require three factors: a chromosomal ski mutation, the presence of M1 dsRNA, and the presence of the new cytoplasmic factor, [D]. We have isolated mutants unable to maintain [D] (mad), at least one of which is due to mutation of a single chromosomal locus. Further, [D] can be cured by growth at 37-39 degrees. We present evidence that [D] is not M, L-A, L-BC or W dsRNAs or mitochondrial DNA, 2 mu DNA, or [psi], but [D] depends on L-A for its maintenance. We also show that [D] is distinct from [B], a cytoplasmic element that allows M1 dsRNA to be stably replicated and maintained in spite of defects in certain chromosomal MAK genes that would otherwise be necessary. [D] activity is blocked by the presence of another extrachromosomal element, called [DIN] (for [D] interference). [D] and [DIN] may be different natural variants of the same molecule.

Genes, Fungal↗
PubMed1986

Serological diagnosis of acute delta hepatitis.

Sixty-three intravenous drug addicts with HBsAg positive hepatitis were studied to evaluate the diagnostic usefulness of hepatitis delta virus (HDV) markers for diagnosis of acute HDV infection. Patients were tested for HBsAg, anti-HBc-IgM, and anti-HD-IgM by radioimmunoassay (RIA), and for hepatitis delta antigen (HD-Ag) by a commercial enzyme-linked immunoassay (ELISA). At least two serum samples at a mean interval of 4 wk were examined from each patient. HDV markers were found in 41 cases. In the first serum sample (obtained within 1-5 wk after onset of illness) HD-Ag was found in 32 cases and was the only HDV marker in 22; in the remaining 10 cases, HD-Ag was found along with total anti-HD, and in 6 of them anti-HD-IgM was also detected. Five additional patients were only positive for total anti-HD, and anti-HD of the IgM class was the only marker in one patient. HD-Ag was found more often in the patients studied during the first 2 wk of illness. In the second serum sample, HD-Ag was never the only marker detected, seven patients were still positive, and in all of them anti-HD was also present. Thirty patients were only positive for anti-HD. Seroconversion from HD-Ag to anti-HD occurred in 20 of 22 (91%) patients. The results suggest that HD-Ag determination by ELISA in the initial serum sample, during the first 2 wk of illness, may be the most sensitive test for the diagnosis of acute delta infection, and that seroconversion to anti-HD usually occurs after the sixth week of illness.

Acute Disease↗
PubMed1986

Immunoprophylaxis of perinatal transmission of the hepatitis B virus: efficacy of hepatitis B immune globulin and hepatitis B vaccine in a low-prevalence area.

One hundred eleven newborn infants born of Spanish hepatitis B surface antigen (HBsAg) carrier mothers were consecutively assigned to one of three treatment groups. Group A was treated with three or four doses of hepatitis B immune globulin (HBIG) in one of three different schedules. Group B received one dose of hepatitis B vaccine (Hevac-B, Pasteur) at birth and at 1, 2 and 12 months. Group C was treated with the same vaccination schedule as group B and in addition received a single dose of HBIG at birth. Comparisons were made in the 85 babies who had strictly completed the immunization schedule and had been followed for at least 12 months. The three immunization protocols were equally effective, since none of the children became a chronic HBsAg carrier or developed acute symptomatic infection. There were five transient and subclinical infections among children who received only HBIG (group A), one transient infection in group B, and one in group C. There seems to be some correlation between anti-HBs levels and degree of protection, since all transient infections in group A occurred in the subgroups who did not maintain protective antibodies during the first 6 months. Although the percentage of responders in the two vaccinated groups did not differ significantly, children who received only vaccine reached higher antibody levels than those who also received HBIG. Our results suggest that any immunization schedule able to maintain anti-HBs levels during the first 6 months of life would be useful to prevent mother-to-infant transmission of the hepatitis B virus in areas where most of the carrier women are expected to be anti-HBe positive and hence relatively less infectious.

Carrier State↗