ABSTRACT
Doses of 60Co gamma radiation with 2.5; 5; 7.5; 10; 15; 20; 25; 30; 35; 40; 45; 50; 55; 60; 80; 160; 320 and 640 Gy were applied to 1,080 snails Biomphalaria straminea, an intermediate host of Schistosoma mansoni, divided in groups containing 30 mollusks. In addition, 60 non irradiated snails were kept as control. Fifty percent of the population was kept in colonies (allowing cross fertilization) while the other half was maintained in sexual isolation (allowing self fertilization) and during one month their growth was observed through the daily measurement of the shell diameter. Results showed that after 20 Gy doses the growth in shell diameter of irradiated snails was greater than that of the control group after 30 days. At this dose the snail size was the greatest, among all isolated groups. The 80 Gy doses also induced the final shell diameter of isolated snails to be greater then that observed in the control groups. As this effect was most evident among the isolated snails, a possible hormonal role may have been involved in the observed phenomena, which is under investigation with the objective of identifying any future applications that this could have to schistosomiasis control
Subject(s)
Animals , Biomphalaria/growth & development , Biomphalaria/radiation effects , Gamma Rays , Dose-Response Relationship, RadiationABSTRACT
A population of 420 snails Biomphalaria straminea, an intermediate host of Schistosoma mansoni, received gamma-rays obtained from a 60 Co source in low-doses (0/2,5/5/7,5/10/15/20 and 25 Gy); half population was kept in colonies (allowing cross fertilization) and other half was mantained in sexual isolation (alowing self fertilization). Results showed that 15 Gy stimulates the fertility of both groups but the colonies were more sensitive and at this dose its fertility overpasses the control group dose. The possible hormonal role played in the observed phenomena is under investigation.
Subject(s)
Animals , Biomphalaria/radiation effects , Fertility/radiation effects , Gamma RaysABSTRACT
A elasticidade da dura-mater tem sido pouco estudada, em que pese a sua importância em próteses e implantes; a metodologia usada até agora para medi-la näo foi caracterizada sendo este um tema muito controverso. Usando 53 amostras frescas de dura-mater parietal humana em testes mecânicos obteve-se as suas respostas elásticas, avaliadas através do deslocamento de volume em uma coluna de soluto salino. Os resultados mostraram um comportamento "Hookeano" nos testes "in vitro", apesar de existirem trabalhos que o negam, quando foi aplicada pressäo hidrostática em amostras de 14 grupos etários diferentes