RESUMO
The evolution of reptilian viviparity is favoured, according to the cold-climate hypothesis, at high latitudes or altitudes, where egg retention would entail thermal benefits for embryogenesis because of maternal thermoregulation. According to this hypothesis, and considering that viviparity would have evolved through a gradual increase in the extent of intrauterine egg retention, highland oviparous populations are expected to exhibit more advanced embryo development at oviposition than lowland populations. We tested for possible differences in the level of egg retention, embryo development time and thermal biology of oviparous Zootoca vivipara near the extreme altitudinal limits of the species distribution in the north of Spain (mean altitude for lowland populations, 235 m asl.; for highland populations, 1895 m asl.). Altitude influenced neither temperature of active lizards in the field nor temperature selected by lizards in a laboratory thermal gradient, and pregnant females selected lower temperatures in the thermal gradient than did males and nonpregnant females across altitudinal levels. Eggs from highland populations contained embryos more developed at the time of oviposition (Dufaure and Hubert's stages 33-35) than eggs of highland populations (stages 30-34) and partly because of this difference incubation time was shorter for highland embryos. When analysed for clutches from both altitudinal extremes at the same embryonic stage at oviposition (stage 33), again incubation time was shorter for highland populations, indicating genuine countergradient variation in developmental rate. Our results indicate that temperature is an environmental factor affecting the geographical distribution of different levels of egg retention in Z. vivipara, as predicted by the cold-climate hypothesis on the evolution of viviparity.
Assuntos
Altitude , Evolução Biológica , Desenvolvimento Embrionário , Lagartos/fisiologia , Oviparidade , Óvulo/fisiologia , Viviparidade não Mamífera/fisiologia , Animais , Tamanho Corporal , Regulação da Temperatura Corporal , Peso Corporal , Clima Frio , Embrião não Mamífero/embriologia , Embrião não Mamífero/fisiologia , Feminino , Lagartos/anatomia & histologia , Lagartos/embriologia , Masculino , Modelos Biológicos , Oviposição , Densidade Demográfica , Espanha , Especificidade da Espécie , Fatores de TempoRESUMO
La evaluación del estado inmunológico en trabajadores expuestos en razón de su trabajo al plomo fue el motivo de este estudio realizado a 14 trabajadores, los que fueron comparados con otros no expuestos, de edad y sexos similares (grupo control).La concentración media de plomo en sangre de la población expuesta fue de 46.9+- 2.3 ng/dl. No hubo diferencias significativas en las concentraciones del suero IgC, IgA e IgM entre las poblaciones estudiadas. Se comprobó la correlación entre la concentración de plomo en la sangre y los niveles de inmunoglobulinas G. Encontramos alteraciones significativas en las pruebas de formación de rosetas (R A y R E)
Assuntos
Humanos , Masculino , Adulto , Imunoglobulinas/imunologia , Chumbo/imunologia , Técnicas Imunológicas/instrumentação , Imunoglobulina A/análise , Imunoglobulina A/imunologia , Imunoglobulina G/análise , Imunoglobulina G/imunologia , Imunoglobulina M/análise , Imunoglobulina M/imunologia , Imunoglobulinas/análise , Chumbo/sangue , Medicina do TrabalhoRESUMO
The evaluation of immunological conditions of 14 workers occupationally exposed to lead and comparison of these results with those of a non-exposed control group with similar age and sex were the aims of this study. It was determined the mean values of lead in blood. In exposed workers it was 46.9 ug/dl while in the control group it was 10.9 ug/dl. Levels of immunoglobulin decreasing while increasing lead concentration in blood were found in those exposed. It was also found a significant diminishment in the formation of rosette in relation to the control group.
Assuntos
Indústria Química , Imunidade Celular/efeitos dos fármacos , Imunoglobulinas/sangue , Síndromes de Imunodeficiência/induzido quimicamente , Chumbo/efeitos adversos , Exposição Ocupacional , Adulto , Animais , Humanos , Deficiência de IgG/induzido quimicamente , Chumbo/sangue , Chumbo/farmacologia , Chumbo/toxicidade , Contagem de Leucócitos/efeitos dos fármacos , Ratos , Formação de Roseta , Linfócitos T/efeitos dos fármacosRESUMO
Se evaluó el estado inmunológico de 14 trabajadores expuestos por razones de su ocupación al plomo, los sujetos estudiados se compararon con otros no expuestos, de edad y sexo similares (grupo testigo). La concentración medida de plomo en la sangre de la población expuesta fue 46,9 ñ 2,3 µg/dl. No hubo diferencias significativas en las concentraciones del suero IgG, IgA e IgM entre las poblaciones estudiadas. Se comprobó la correlación entre la concentración de plomo en sangre y el inmunoglobulinas G
Assuntos
Humanos , Masculino , Adulto , Exposição Ambiental/efeitos adversos , Imunoglobulinas/imunologia , Chumbo/imunologia , Exposição Ambiental/análise , Imunoglobulinas/análise , Chumbo/sangue , Medicina do TrabalhoRESUMO
The evaluation of immunological conditions of 14 workers occupationally exposed to lead and the comparison of these results with those of a non-exposed control group with similar age and sex were the aims of this study. It was determined the mean values of lead in blood. In exposed workers it was 46.9 micrograms/dl while in the control group it was 10.9 micrograms/dl. Levels of immunoglobulin decreasing while increasing lead concentration in blood were found in those exposed. It was also found a significant decrease in the formation for rosette in relation to the control group.
Assuntos
Agamaglobulinemia/induzido quimicamente , Formação de Anticorpos/efeitos dos fármacos , Imunidade Celular/efeitos dos fármacos , Intoxicação por Chumbo/imunologia , Chumbo/farmacologia , Doenças Profissionais/imunologia , Adulto , Humanos , Chumbo/efeitos adversos , Chumbo/sangue , Masculino , Doenças Profissionais/induzido quimicamente , Exposição Ocupacional , Formação de RosetaRESUMO
The evaluation of immunological conditions of 14 workers occupationally exposed to lead, and the comparison of these results with those of a non-exposed control group, with similar age and sex, were the aims of this study. It was determined the mean values of lead in blood. In exposed workers it was 46.9 micrograms/dl; while in the control group it was 10.9 micrograms/dl. Levels of immunoglobulin decreasing while increasing lead concentration in blood were found in those exposed. It was also found a significant lessening in the formation of rosette in relation to the control group.
