Culture of rat renal medullary tissue in media made hyperosmotic with NaCl and urea.

During antidiuresis, the rat kidney maintains a variable and steep osmotic gradient from the cortex (300 mOsm) to the inner medulla (at least 2,600 mOsm). Therefore, cells in the renal medulla must be able to adapt to a variably hyperosmotic environment. We have examined the ability of tissue fragments taken from various points on the cortical-medullary axis to survive and grow when cultured in media made hyperosmotic with urea and NaCl.

Rat renal papillary tissue explants survive and produce epithelial monolayers in culture media made hyperosmotic with sodium chloride and urea.

The capacity of papillary cells to adapt to elevated osmotic concentrations is unusual among mammalian cells. This capacity was evaluated by using primary tissue culture. Viability and growth of cells in rat renal papillary tissue explants were assessed after culture in media adjusted with urea and sodium chloride to various osmotic concentrations between 300 and 1,500 mOsm/kg water.

In vitro study of bacterial growth in continuous ambulatory peritoneal dialysis fluids.

We examined the in vitro survival of bacteria in continuous ambulatory peritoneal dialysis effluents of patients with clinical peritonitis and those without peritonitis. Standard strains of coagulase-negative staphylococci (CNS), Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were inoculated into the fluids, and portions were plated for bacterial counts at 0.5, 4, 24, 48, 72, and 96 h.

COMPARISON OF CHROMATOPHOROTROPINS FROM THE HORSESHOE CRAB LIMULUS POLYPHEMUS, AND THE FIDDLER CRAB, UCA PUGILATOR 1.

1. Extracts of the central nervous system of the horseshoe crab, Limulus polyphemus, were assayed for chromatophorotropic activity on the fiddler crab, Uca pugilator. The extracts caused pigment dispersion in the melanophores and pigment concentration in the leucophores but had no effect on the erythrophores.