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[Method of gradient chromatography for the isolation of purified lipid fractions from nerve tissue in studies using radioactive carbon, C14].

A method is developed for separation of lipids from nervous tissue by thin-layer chromatography in silica gel. Cholesterol and "minor" lipids were removed from the start by the first chromatography in the system ether-benzol-ethanol-acetic acid. Phospholipids and galactolipids, which remained at the start, were separated by the repeated chromatography in the system chloroform-methanol-NH4OH. The purified fractions of cholesterol, cerebrosides, sulfatides and the total fraction of phospholipids were obtained from 100-150 mg of nervous tissue in amounts, sufficient for estimation of their specific radioactivity in experiments with 14C.

Animals↗
PubMed1985

Time course of the total and radioactive carbon dioxide production by piglets receiving dietary [14C]phenylalanine.

The influence of experimental protocol (i.e., timing of feeding and of the collection of expired carbon dioxide) upon the sensitivity of using the oxidation of a labelled amino acid as an indicator of the adequacy of the dietary amino acid balance was investigated using 2.5-kg piglets confined in ventilated chambers. In the first experiment it was shown that consumption of two meals, each of 20 g and separated by 2 h, after an overnight fast resulted in a rapid rise in carbon dioxide concentration in the air withdrawn from the chamber. The concentration peaked 12 min after the second meal and remained elevated for 50 min. In the second experiment the piglets received two meals containing three levels of either lysine (8, 10, and 12 g/kg) or tryptophan (1.3, 1.8, and 2.0 g/kg) plus 10 microCi L-[alanine-1-14C]phenylalanine (1 Ci = 37 GBq) in each meal. Radioactivity released as 14CO2 peaked in the second hour following the last meal, but there was such great variation in the mean for the three diets that they were not statistically different. However, in the third hour following the second meal both the means and their variances had decreased with the differences between the diets being statistically significant for this time period. An experiment with varying levels of tryptophan showed a similar effect of meal consumption on 14CO2 release. The third experiment confirmed the effect of time of collection upon the statistical significance of the dietary amino acid balance measured by the release of radioactivity from [14C]phenylalanine.

Animals↗
PubMed1975

Effects and distribution of acute fat embolism in spontaneously breathing dogs using radioactive carbon triolein.

The acute effects of a triolein infusion in dogs were secondary to the mechanical effects of this neutral fat which was distributed in the pulmonary and systemic vascular tree of all organs without inflammatory change. Hypoxia developed immediately and became progressively worse as the infusion was continued. Pulmonary hypertension developed during the fat infusion without pneumonia, congestive heart failure or pulmonary edema. There was a slow leak of 14C triolein into the systemic circulation rather than a rapid shower, and this radioactive fat was recirculated between the pulmonary and systemic vasculature. Seventy-six per cent of the 14C triolein was retained in the lungs. Terminally, the dogs had a respiratory arrest without cardiac decompensation, cardiac arrest or pulmonary edema; cerebral fat embolism in addition to severe hypoxia appears to be the cause.

Acute Disease↗
PubMed1975

Noninvasive cardiac evaluation (NICE) of intracardiac shunts using inhaled radioactive carbon dioxide.

A totally new, noninvasive technique is presented for the detection and analysis of left-to-right cardiac shunts. Five millicuries of oxygen 15-labeled carbon dioxide is administered by a single-breath inhalation technique. The resultant lung washout curve accurately reflects the presence or absence of a shunt. The quantitative studies are promising, but the method must be compared with standard techniques in a statistically significant series. This work is in progress.

Carbon Dioxide↗