Inactivation of Cryptosporidium parvum oocysts in field soil.

Cryptosporidium parvum oocysts from dairy calves are believed to regularly contaminate watersheds. Identifying oocysts and measuring their viability in the natural environment are important elements in estimating the risk posed by this resistant organism. A 152 day field study was conducted to measure the viabilities of oocysts inoculated into 25 sampling points. Water potential, pH, and ammonium content were also measured at the same 25 sampling sites. A three-dimensional mapping program (Surfer) was used to create 3-D maps of the viabilities of C. parvum oocysts and other factors measured during the experiment. The results indicate that 3-D graphical presentation may be a useful means to identify potential sites of greatest risk of oocyst survival and could indicate areas where natural conditions are causing the most rapid oocyst inactivation, and this method can be a means for the future measurement of microorganism inactivation in the natural environment.

Neuron-specific enolase is a useful marker of neuroendocrine origin in pheochromocytoma cell culture

Neuron-specific enolase (NSE) has been used as a marker for neuroendocrine tumors either in immunocytochemical studies or in serum measurements. ln this paper NSE levels were determined in cultured pheochromocytoma cells to test whether it is also a useful marker ín cell culture of tumors derived from neuroendocrine system. Cultured pheochromocytoma cells came from a primary explant and were grown in RPMI supplemented with 20 per cent fetal calf serum, 100 mug/mL ampicillin and 100 mug/mL streptomycin. NSE was measured in culture medium and cell homogenates. Samples from different pheochromocytoma cultures were analyzed and compared to normal cultured fibroblast cells derived from human skin. NSE was measured by a commercially available radioimmunoassay kit. NSE levels were higher in cell homogenates as compared to those in culture medium, reaching levels as high as 6-fold in the former in TE cell line (26.46 ng/mL and 4.39 ng/mL respectively. Serial NSE measurements in culture medium from TE cell line evidenced decreasing values in subsequential subcultures (from 9.24 ng/mL during primary explant to 1.7 ng/ml. in the 10th subculture). In cultured normal fibroblasts, NSE levels in cultured media were definitely lower than those obtained from pheochromocytoma cultures. These preliminary data suggest that NSE may be a useful marker of neuroendocrine derived tumors, such as pheochromocytoma, in culture. Thus, the simplicity and availability of NSE radioimmunoassay provides an alternative to catecholamine measurement to better characterize pheochromocytoma cell lines in culture, with the advantage of faster results at lower costs.

Fatores que influenciam o sucesso em cultura de fibroblastos. / Factors influencing the sucess in fibroblasts culture

Relataram-se diferentes fatores que podem influenciar no sucesso do estabelecimento do metodo de cultura de fibroblastos. Tres linhagens celulares foram cultivadas advindas de: pele de embriao de galinha, fibroblastos de rato (ST1) e pele humana normal. Mostrou-se a evolucao inicial do crescimento celular de explantes primarios de pele humana e de embriao de galinha