Using flowering times and leaf numbers to model the phases of photoperiod sensitivity in Antirrhinum majus L.

A model has been developed that can be used to determine the phases of sensitivity to photoperiod for seedlings subjected to reciprocal transfers at regular intervals between long (LD) and short day (SD) conditions. The novel feature of this approach is that it enables the simultaneous analysis of the time to flower and number of leaves below the inflorescence. A range of antirrhinum cultivars were grown, all of which were shown to be quantitative long-day plants. Seedlings were effectively insensitive to photoperiod when very young (juvenile). However, after the end of the juvenile phase, SD delayed flowering and increased the number of leaves below the inflorescence. Plants transferred from LD to SD showed a sudden hastening of flowering and a decrease in leaf number once sufficient LD had been received for flower commitment. Photoperiod had little effect on the rate of flower development. The analysis clearly identified major cultivar differences in the length of the juvenile phase and the photoperiod-sensitive inductive phase in both LD and SD.

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.

Sister-chromatid exchange frequencies induced by metrifonate in mammalian in vivo and in vitro systems.

Metrifonate is a drug widely used to cure several helminthiases in man including cysticercosis. In this study we determine its capacity to induce SCEs in vivo and in vitro using the fluorescence-plus-Giemsa technique. In the human lymphocyte system we tested 10, 20, 30, 40, 50 and 60 micrograms/ml added at 24 h of culture with a duration of 72 h. The results showed a SCE inducing effect with the exception of the first tested dose (10 micrograms/ml), but without a dose-response expression. A cell cycle progression delay was seen with the three highest dosages. In the mouse bone marrow we tested 30, 60 and 120 mg/kg in a 24-h experiment, and the results indicated an SCE increase only with the highest dose. No modification of the cell proliferation kinetics was observed.

[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)

Experimental treatment of cysticercosis with metrifonate.

Thirty cysticercous patients were treated with metrifonate in doses of 7.5 mg/kg given for five consecutive days, with intervals of two weeks until completion of six series. The symptoms originated by drug reaction were mild and transitory. The results obtained after treatment demonstrated the effectivity in cerebral ocular and musculocutaneous cysticercosis, corroborated by clinical evaluations like: neurological, ophtalmological and psychiatric examinations; routine laboratory tests; special examinations like indirect immunofluorescence and hemagglutination, immunoglobulin quantitation and cholinesterase activity and by special cabinet studies like electroencephalogram, retinal fluorangiography, axial computerized tomography. The postreatment observation time varied from six months to nine years; in no case reactivation was observed.

Tratamiento experimental con metrifonato en la cisticercosis. / Experimental treatment of cysticercosis with metrifonate

A 30 pacientes cisticercosos se les administro metrifonato a la dosis de 7,5 mg/kg de peso durante cinco dias consecutivos. Se repitio el tratamiento despues de dos semanas hasta completar un numero de seis series. La sintomatologia indeseable del medicamento fue transitoria en los casos que la presentaron, y cedio al terminar la serie. Los resultados obtenidos demostraron que el medicamento fue eficaz en la cisticercosis cerebral, ocular y musculocutanea, lo que se corroboro por evaluaciones clinicas como examenes neurologicos, oftalmologicos y psiquiatricos, examenes de laboratorio, examenes sistematicos y pruebas especiales como inmunofluorescencia y hemaglutinacion indirecta, cuantificacion de inmunoglobulinas y actividad enzimatica de colinesterasa, y por estudios especiales de gabinete que incluyeron electroencefalograma, fluoroangiografia retiniano y tomografia axial computarizada. El tiempo de observacion postratamiento vario entre seis meses y nueve anos,sin que en ningun caso se presentara reactivacion de la sintomatologia

Indirect immunofluorescense reaction in cysticercosis.

The indirect immunofluorescence reaction (IIR) was used to investigate cysticercosis in the serum of 604 subjects; control group I, with 100 subjects gave the following results: 2 per cent positive, 3 per cent weak positive and 95 per cent negative. Group II had 35 cases of cysticercosis, showing 94.28 per cent positive, 5.71 per cent weak positive and 0 per cent negative. In group III, with 100 patients, other diseases were studied showing 5 per cent positive, 7 per cent weak positive and 88 per cent negative. Group IV, with 364 cases with possible cysticercosis, showed 48.90 per cent positive, 10.98 per cent weak positive and 40.10 per cent negative. In group V, five cases of Taenia saginata parasitosis were studied showing a weak positive reading.