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E Pareja

Publications and source records attributed to E Pareja.

23 records · Page 2Linked to original sources
PubMedDate not supplied

Repression of class I H-2K, H-2D antigens on GR9 methylcholanthrene-induced tumour cell clones is related to the level of DNA methylation.

The correlation between gene expression and DNA methylation is well established. In the present study we examined DNA methylation as a potential regulatory mechanism of class I histocompatibility antigen expression. We selected for study two cell clones from the same mouse tumour (GR9). One of them is H-2 class I-positive (A7) and the other negative (B9). Using five enzymes and three different probes, no rearrangement or deletion was detected in the MHC class I genes of the negative clone compared with the positive one. These results do not provide an explanation for the differences observed in the expression of class I antigens in A7 (Kd, Dd positive) and B9 (Kd, Dd negative). We then studied the DNA methylation status in both clones by Southern blot analysis. Clear differences between the Kd, Dd positive and negative clones were detected. Furthermore, both Kd and Dd were clearly expressed after culturing the H-2 class I negative clone with the demethylating agent 5-azacytidine. These results suggest that the methylation of certain MHC cytosines is a regulatory mechanism of H-2 class I gene expression.

Animals↗
PubMedDate not supplied

Differential expression of HLA class I and II antigens in primary and metastatic melanomas.

Class I and II histocompatibility antigen expression was studied in cryostat sections of biopsy tissues from 15 patients diagnosed as suffering from malignant melanoma, using monoclonal antibodies against HLA class I and II monomorphic determinants and an indirect immunofluorescence technique. Class I antigens were detected in three of the four primary melanomas and in five of the eleven metastatic melanomas. Class II antigens were expressed only in metastatic melanomas, in three out of eleven cases. Some tumour cell suspensions were obtained and short-term cultures were established. Radiobinding and immunoprecipitation studies were carried out in two cases, named M6 and M8. The results were comparable to those obtained with direct immunofluorescence. We modulated the expression of class I and II HLA antigens with interferon in M6 when adapted to tissue culture. This melanoma was class I and II negative; after IFN gamma treatment it became strongly positive for class I and II antigens. In addition we have demonstrated, using Southern blot analysis with the restriction enzymes PvuII and EcoRI, that the M6 melanoma does not have any detectable alterations in its class II beta genes.

Adult↗
PubMedDate not supplied

[Comparative study on the protective effect of two immunization schemes using a hepatitis B recombinant vaccine in vulnerable health science students].

OBJECTIVE: Demonstrate the protective effect of hepatitis B in vaccine vulnerable health sciences students, under 30 years with three schemes the vaccination, two of them are conventional three doses and another one with two doses. HYPOTHESIS: Three schedules of vaccination dosage schemes hepatitis B produce antibody response over 10 IU/ml. DESIGN: Analytical, experimental, longitudinal., prospective and concurrent cohort study. MATERIALS AND METHOD: 100 vulnerable female and male students of the Medical Technology Faculty of the UNMSM Medical School were enrolled at first. 89 students completed the final analysis due to the inclusion and exclusion criteria in accordance with the study purpose. A vaccine dosage of 20 ug of surface antigen in 1 mL through three dosage schemes was administered: month 0, 1, 6; month 0, 1, 2; and month 0, 1. Blood samples were taken before and 1, 2, 6, and 7 months after the first dosage administration to determine the anti-HBs level. Anti-HBs approximately 10 mIU/mL was defined as seroprotective value. RESULTS: 89 students under 30 years (average age: 23.5 years). 46 (51.7%) male individuals, and 43 (48.3%) female individuals.12.4% of students reached protection within 30 days from the first dosage; 98.8% reached protection within 30 days from the second dosage; and 100% reached protection 180 days later. After the second dosage, the three groups reached protection values, and at the end of the study, the average antibody levels were between 532.7 mIU/mL and 1237.2 mIU/mL. CONCLUSIONS: This study showed an equivalent protective effect 7 months after the first dosage. An equivalent protective effect for hepatitis B was reached through three different vaccination schemes: conventional three dose scheme (month 0, 1, 6); two dose brief scheme (month 0, 1); and three dose brief scheme (month 0, 1, 2). A two dose scheme is suggested for individuals under 30 years, which would imply a higher compliance rate, lower cost, and a similar protection benefit.

Adult↗