Bioavailability in rabbits of formaldehyde from durable-press textiles.

Carbon-14-labeled formaldehyde was used per se, or was used in the synthesis of dimethyloldihydroxyethyleneurea (DMDHEU), which was incorporated into cotton or cotton/polyester blend fabric. Patches of the fabric containing known quantities of radioactive DMDHEU were applied to the backs of New Zealand White rabbits for periods up to 48 h. The rabbits were placed in specially constructed metabolism chambers designed to prevent either inhalation of volatile material emanating from the fabric or interference of any volatile material from the fabric with trapping of expired carbon dioxide. The results of the studies indicate that aqueous formaldehyde covered with a latex barrier is absorbed and retained in the layers of skin in direct contact with the formaldehyde. Approximately 65% of a dose of [14C] formaldehyde was recovered in skin 4 h after application. Skin samples from the backs of rabbits to which durable-press fabric prepared from radiolabeled DMDHEU had been applied were found to have 0.09-2.61% of the total 14C contained in the cloth patches. The levels of radioactivity recovered from the skin varied with degree of occlusion of the cloth, presence or absence of perspiration, type of synthesis used for the preparation of DMDHEU, and whether cotton or cotton/polyester blend fabric was used. Other tissues and organs had only low levels of radioactivity. Injected [14C] formaldehyde was rapidly expired as 14CO2 (28.6% of the dose within 4 h; 37.0% within 48 h). Metabolism and distribution of formaldehyde was found to be dependent on route of administration: i.e., topical application resulted in high skin levels, whereas intravenous injection led to rapid pulmonary and renal excretion and retention of radioactivity in liver, kidney, and blood.

Cell size and plamitate-1-14c turnover of rabbit marrow fat.

Adipose tissue is a major component of normal rabbit marrow. Morphological considerations suggest an active role for this tissue in hematopoiesis. This hypothesis was tested by injecting 50 micronCi of palmitate-1-14C intravenously into fed, hematologically normal New Zealand rabbits. The animals were sacrificed 24 hr later and the femoral marrow removed. Samples of subcutaneous and perinephric fat were taken for comparison. The fat cells were isolated by the Rodbell method and the diameters measured. Incorporation of the 14C-palmitate in the triglyceride fraction was determined and the composition of the fatty acids was measured by gas chromatography. The mean diameter of the marrow fat cell was 46 micronm (mean cell volume 55 pl); the mean diameter of the perinephric fat cell 70 micronm (mean cell volume 200 pl). 14C-Palmitate turnover per gram triglyceride was some fivefold greater in the marrow fat; however, when expressed on a cell basis, the turnover for the marrow and perinephric fat cell was similar. The marrow fat contained a higher concentration of unsaturated fatty acids. These findings suggest that there is greater lipolysis and lesser storage in the marrow fat than in the perinephric.

Immunochemical studies of organ and tumor lipids XXI. Sensitivity and specificity of the cytolipin F - sheep erythrocyte system.

The sensitivity and specificity of the sheep erythrocyte - anti-sheep erythrocyte system to inhibition by pure cytolipin F has been studied with 5 antisera, in order to compare it with the rat erythrocyte-anti-rat lymphosarcoma system and its inhibition by pure cytolipin R. The cytolipin F - sheep erythrocyte system is much more sensitive than the cytolipin R - rat erythrocyte system, inhibition of hemolysis of 6 x 10(6) sheep cells being produced by 10 ng of cytolipin F (combined with a four-fold quantity of lecithin) compared with inhibition of hemolysis of 10(6) rat cells by 50 to 100 ng of cytolipin R (also combined with lecithin). Differences in sensitivity are attributed to the larger number of available cytolipin F determinants on sheep erythrocytes compared with cytolipin R determinants on rat erythrocytes. Studies of the auxiliary lipid enhancement of cytolipin F activity by galactocerebroside, lactosyl ceramide (cytolipin H), and lecithin are also reported.