Class II major histocompatibility complex typing across the ethnic barrier in pemphigoid gestationis. A study in Mexicans.

BACKGROUND: Pemphigoid gestationis (PG), also called herpes gestationis, is a rare autoimmune disease of pregnancy or puerperium (estimated 1 out of 50,000 pregnancies among Caucasians). A previous series has demonstrated an association of PG with human leukocyte antigen (HLA)-DR3 or HLA-DR4 haplotypes. While these haplotypes are most commonly found in individuals of European ancestry, they have also been found in African-American patients affected with PG. PG has rarely been reported in other ethnic groups, and the HLA association in non-Europeans has not been examined. METHODS: We have characterized eight patients of Mexican ancestry who have PG by clinical, histologic, and immunofluorescence criteria. Class I and class II major histocompatibility complex (MHC) antigens were studied by standard microlymphocytotoxicity assays. Class II MHC antigens were further studied by polymerase chain reaction (PCR) amplification of HLA-DRB1, DQA, and DQB genes and allele-specific oligonucleotide hybridization. For comparison purposes, we used results obtained from a group of 100 ethnically matched healthy individuals. RESULTS: We found that all eight patients had the HLA-DR3/DR4 phenotype; all HLA-DR3 haplotypes were HLA-DRB1*0301, DQA1*0501, and DQB1*0201, whereas half of the HLA-DR4 haplotypes were from the DRB1*0401 subtype and the other half were DRB1 *0407. CONCLUSIONS: These results suggest that, in Mexicans, the genetic susceptibility for the development of PG is strongly influenced by the genetic admixture of Caucasian origin, and the role of class II MHC antigens in the pathophysiology of this disease is confirmed.

[The biological activity of Ricinus communis on the housefly (Musca domestica)]. / Actividad biológica de Ricinus communis sobre mosca doméstica (Musca domestica).

The insecticide effect of a lectin obtained from Ricinus communis (castor-oil plant) on a population of houseflies from San José de Las Lajas was evaluated. Assays were performed with adults and larvae. Mortality was higher as the time f exposure to the extract increased DL50 was of 353.4 p.p.m. after 72 hours of exposure. It was observed a remarkedly significant reduction of the pupal development in the presence of the extract, which shows its insecticide activity.

[Mechanisms of resistance to organophosphate insecticides, carbamates, and pyrethroids in populations of Musca domestica L. (Diptera: Muscidae)]. / Mecanismos de resistencia a insecticidas organofosforados, carbamatos y piretroides en poblaciones de Musca domestica L. (Diptera: Muscidae).

Resistance to organophosphorus insecticides (malathion, chlorpyriphos, pyrimiphos-methyl); carbamates (propoxur); and pyrethroids (permethrin, deltametrine, cypermetrine, and lambda cialotrine) was studied in field populations of Musca domestica; results were compared with a susceptible reference strain. The method of topic application was employed in the bioassays; the synergist effect of the s,s,s tributyl phosphorotrioate and of the piperonyl butoxide (PB) was also tested. Biochemical microplate tests were also carried out to determine the presence of esterase and acetylcholinesterase enzymes in the three populations. Generalized resistance to malathion (FR = 264.6; 164.0; 154.7) was observed.