N,N',N''-Triethylenethiophosphoramide ([14C]thiotepa) accumulation by L1210 cells is a biphasic process. A very rapid initial phase is followed by a much slower second phase that reflects accumulation of radioactivity in a form that is not lost or exchanged when cells are resuspended and incubated in drug-free medium for up to 8 h. In this study we attempted to characterize this nonexchangeable...

Despite considerable interest in using stable-hydrogen isotope ratio (deltaD) measurements in ecological research, it was previously unknown whether hydrogen derived from drinking water, in addition to that derived from diet, contributed to the nonexchangeable hydrogen in animal tissues. We raised four experimental groups of quail (Coturnix coturnix japonica) from hatch on two isotopically dist...

The mechanism of uptake of Adriamycin was investigated in chick embryo heart and liver cells and in murine L5178Y lymphoblasts in vitro. Drug uptake at 4°C for 15 s due to rapid association accounted for a celhmedium distribution ratio of 104 ±14 (SE) in heart cells, 10.2 ±1.3 in liver cells, and 10.3 ±1.5 in L5178Y lymphoblasts. On thin-layer Chromatographie analysis, 98% of the radioactiv...

Corn roots or washed corn root tissue exposed to cold shock absorb 20 to 24% more (45)Ca(2+) into a nonexchangeable phase than control roots. Addition to fusicoccin largely prevents this additional calcium influx. The results are discussed in relation to injury-induced changes in membrane permeability of root cell membranes.

Corn (Zea mays L.) grown on sandy Atlantic Coastal Plain soils is often unresponsive to applications of K fertilizer. As part of a field study on the response of irrigated, intensively managed corn to K applications, we characterized four representative Hapludults from the Delaware Coastal Plain and evaluated their K status. The soils were generally quite sandy with maximum clay contents of 11....