RESUMO
The alpha-thalassaemias are group of inherited anaemias. Their severity is known to increase with the number of alpha-globin genes deleted. Employing different types of restriction enzymes, we found that alpha-thalassaemia-2 are more common than held previously. On the basis of our results we also anticipate that the haplotype alpha alpha alpha anti3.7/ occurs at a higher frequency.
Assuntos
Talassemia alfa/etnologia , Southern Blotting , DNA/sangue , Eletroforese em Gel de Ágar , Haplótipos , Humanos , Incidência , Mapeamento por Restrição , Arábia Saudita/epidemiologia , Talassemia alfa/sangue , Talassemia alfa/epidemiologiaRESUMO
The mutagenicity of dacarbazine was assayed in an in vivo test utilizing mouse bone marrow cells. The dose rates used in the experiments were computed according to the standard surface area of the mouse and were proportional to the human dose rate. These were 0.27, 0.44 and 0.60 mg/30 g body weight, each given twice daily at an interval of not less than 6 h. The duration of drug treatment was 24, 48 and 72 h. This alkylating agent proved to be mitodepressive and produced a 3-fold reduction in the mitotic index. The drug also induced chromosome anomalies mainly in the form of chromatid gaps and breaks. These anomalies were proportional to dose rate and duration of drug treatment.
Assuntos
Medula Óssea/efeitos dos fármacos , Dacarbazina/toxicidade , Animais , Medula Óssea/ultraestrutura , Aberrações Cromossômicas/efeitos dos fármacos , Relação Dose-Resposta a Droga , Cariotipagem , Camundongos , Índice Mitótico/efeitos dos fármacos , Testes de MutagenicidadeRESUMO
The diploid chromosome number is 2n = 38. The fundamental number is 70. The autosomes consist of 11 pairs of metacentric, 5 pairs of submetacentric and 2 pairs of acrocentric chromosomes. The sex chromosomes are both acrocentric, the X-chromosome is the largest.
Assuntos
Cromossomos , Muridae/genética , Animais , Diploide , Feminino , Cariotipagem , Masculino , Arábia SauditaRESUMO
DNA fibre autoradiography has been used to study the effects of temperature on the replication of chromosomal DNA of Xenopus laevis cells in tissue culture at 18, 23 and 28 degrees C. Pulse/stepdown labelling shows that the DNA replicates bidirectionally. Origin-to-origin distances (initiation intervals) vary, but the range of and the mean initiation intervals at all three temperatures are much the same. The mean interval between initiation points is of the order of 60 to 66 microns. Staggering of initiation is evident at all three temperatures. Evidence against the existence of replication termini is provided. The rates of progress of DNA replication forks are 6 microns/h at 18 degrees C, 10 microns/h at 23 degrees C and 16 microns/h at 28 degrees C.
