Antibody detection against Borrelia burgdorferi in horses located in the suburban areas of Monterrey, Nuevo León.

The aim of the present study was to determine the presence of Borrelia burgdorferi antibodies in horses from the metropolitan area of Monterrey, Nuevo León, México. Blood serum was obtained from a total of 100 horses residing at different counties in the area. From each animal data was obtained on age, sex, county of residence, presence of ectoparasites and clinical signs. All sera samples were analyzed by indirect immunofluoresence and the sera that resulted positive to this test was analyzed by Western blot. The serological test yielded 34 positive sera at 1:64 dilution, and from them 6 were positive at 1:128 dilution, 3 at 1:256, and only one at 1:512. Confirmation of the infection by Western blot was obtained only in the sample positive at the 1:512 dilution. These results shown a low frequency of seropositivity to B. burgdorferi of the horses in the area, confirming previous studies indicating that in northeast Mexico Lyme disease is present in different animal species.

Serological activity of white-tail deer against several species of Brucella.

In Mexico, brucellosis is a widely distributed disease of domesticated ruminants, but its frequency in wild ruminants has not been documented. Since northeast Mexico is the main distribution area of white-tailed deer and has been reported as an area positive for brucellosis in domesticated species, the present study was conducted in order to determine serological activity against several species of the genus Brucella in white-tailed deer. A total of 208 sera of white-tailed deer were collected during the springs of 1994 and 1995 in the north part of the states of Nuevo León and Coahuila. Each serum was analyzed for the detection of antibodies against two smooth (B. abortus and B. melitensis) and one rough (B. ovis) species of the genus Brucella. The serological tests used for the determination of the presence of antibodies against Brucella were card and plate agglutination for B. abortus, plate agglutination and rivanol precipitation for B. melitensis, and agar gel immunodiffusion for B. ovis. Each assay had positive and negative controls. None of the analyzed samples was found to be positive, and only two sera showed partial plate agglutination against B. melitensis at a dilution of 1:25; however, at higher dilutions and to the rivanol precipitation test the same samples were negative. Therefore, the percentage of positive sera was estimated at 0% (0/208). This result makes evident the absence of positive white-tailed deer against Brucella in the sampled area, despite that this disease is considered present in domesticated species. Therefore, white-tailed deer does not have, at the present time, an important role for the dispersion of the disease. The same result has been reported in other countries.

[Activity of ribosomal genes and the association with acrocentric chromosomes in trisomy 21 and habitual abortion]. / Actividad de genes ribosomales y asociación de cromosomas acrocéntricos en la trisomía 21 y el aborto habitual.

The frequency of silver stain of the nucleolus organizer regions (NOR's) an indicator of the transcriptional activity of the DNAr, and the frequency of the association between acrocentric chromosomes (A.A.C.), possible indicator of the non-disjunction risk, were studied in the chromosomes in metaphase of eight married couples with regular 21 trisomy children, five couples that have had consecutive miscarriages and fifteen control normal persons, eight men and seven women. In this three groups the mean age was 30 years and they were compared according to sex. Another seven couples, with a mean age of 52 years also parents of 21 trisomic were compared against the group of young parents of 21 trisomics in order to analyze the age effect. Moreover there were studied the trisomic children of eight of the above couples in order to find out the effect of the supernumerary 21 chromosome. In all the groups the correlation coefficients between the frequency of NOR's-Ag+ and the A.A.C. were determined. It was found that the young group of parents of trisomic and the couples with consecutive miscarriages, both men and women, had a significant increased frequencies of NOR's-Ag+ and A.A.C. in comparison to controls. In the parents of trisomic, either men or women it was found a significant diminished level in the frequency of NOR's-Ag+ when the age increased, meanwhile raise in the frequency of A.A.C. with the increase of age was observed only in the women. A positive correlation between the frequencies of NORs-Ag+ and A.A.C. was found in the women of the control group and in the young mothers of trisomic.(ABSTRACT TRUNCATED AT 250 WORDS)