Elmer S. Miller

Effect of adrenalectomy on rate of fat absorption.

Summary The methyl esters of the fatty acids of corn oil are absorbed at the same rate as unaltered corn oil. Adrenalectomy has no significant effect on the absorption of either of these two fats. The rate of absorption of both methyl esters of corn oil fatty acids, and unaltered corn oil is the same for each hour up to 6 hours after feeding.

Photoelectric Spectrophotometry Applied to Studies in Fat Metabolism.

Conclusion Eleostearic acid is quickly changed to a new acid in vivo. Distribution and metabolism of this acid has been followed by spectroscopic analysis and large differences found among several tissues.

Quantitative Spectroscopic Analysis of Stem “Tracheal” Fluids for Inorganic Constituents.

Summary (1) A rapid and reliable method for quantitatively analyzing “tracheal” fluid by emission spectroscopy has been described in detail. (2) Evidence has been presented showing that a correction should be made for electrode impurities. (3) Typical analyses of potato tracheal fluid for B. P. Mn, Mg, Cu, and Ca are presented.

A Spectrophotometric Method for the Study of Fat Transport and Phosphorylation

Summary By conjugating the double bonds of the linoleic acid of corn oil, a fat may be prepared which can be spectroscopically distinguished and quantitatively measured in body fat. A method for the extraction and determination of this tagged fat in animal tissues has been described.

Inheritance of Chlorophyll in F1 Grosses Made Reciprocally Between Selfed Lines of Corn.

Summary These studies show that maternal inheritance of chlorophylls as measured by a series of crosses made reciprocally between high and low chlorophyll inbred lines of corn is not significant, and that male and female parents each contribute equally to the genotype of the F1 cross in respect to chlorophyll concentration.

In vitro Incorporation of Fatty Acids in Phospholipids of Intestinal Mucosa.

Sinclair, 1 using elaidic acid, found that phospholipids of the intestinal mucosa after feeding fat, contained some of that fed fat. Perlman, Rubin, and Chaikoff 2 later showed that fed, radioactive phosphorus also became incorporated in the phospholipids of the intestinal mucosa. Both of these findings have been repeatedly confirmed. Robinson, et al., 3 have also shown that slices of intestinal mucosa incubated in a Warburg apparatus with radioactive phosphorus would bring about an incorporation of radioactive phosphorus in the mucosal phospholipids. Using the conjugated, unsaturated fatty acids of corn oil as a tagged fat 4 the in vitro incorporation of fatty acids in the intestinal mucosal phospholipids has been studied. Male, albino rats were anesthetized with ether and their abdomens opened. Three cc of an emulsion containing bile salts, lipase (pancreatin), water, and tagged fat† was injected into the duodenum and the abdomen closed. After 15 minutes the rats were again etherized and the intestines washed with saline, then alcohol and finally with more saline. After a 15-minute absorption period about 30% of the total fat in the mucosa will be tagged fat. The mucosa of 2 rats was freed from intestinal muscle and immediately placed in a boiling water bath for 5 minutes. The intestines of the other animals were placed in beakers of normal saline and allowed to incubate at room temperature for various lengths of time. In the experiment marked with an asterisk (Table I) the intestines were slit lengthwise and placed in oxygenated, glucose Ringers at 37°C. There was no alcohol used in washing these intestines. In each case when the incubation time was complete the mucosa was removed and immediately placed in a boiling water bath. The mucosal samples were then frozen, dried and extracted.

Discussion of Some Errors in Quantitative Spectrophotometry.

Recent advances in photoelectric spectrophotometry reported by Hogness, et al., 1 and Smith 2 now permit precise measurements of absorption coefficients. The techniques described by these workers have made it possible for investigators in different laboratories to obtain concordant results. Kuhn, 3 Miller, 4 , 5 and Van Der Hulst 6 have pointed out several analytical applications of spectrophotometry in biological chemistry. However, these analytical procedures are valid only when the investigator is cognizant of the limitations imposed by certain errors. This paper concerns anomalous transmission values (or i. e., Io/I)† that are caused by scattered radiation or absorption due to impurities. Data presented in Graph 1 illustrate the discrepancies in carote-noid absorption curves of solutions containing 0.6% butter and solutions with equivalent carotenoid concentrations but no butter. In this experiment 20% diethyl ether and 80% ethanol (by volume) were employed as solvent. When the absorption curves were measured on aliquot portions of butter—carotenoid solutions at one hour intervals, the difference between the last curve, in the series, and the standard curve (no butter present) was always less than when similar comparisons were made with curves obtained on earlier runs. When the absorption curves were run on butter solutions that had stood for 15 to 24 hours, no deviation was observed from the standard curves. In experiment 2, the transmittance was measured on butter-carotenoid solutions in spectral regions where the carotenoids do not absorb. The Io deflections were adjusted to 100.0 ± 0.5 cm. Table I summarizes the I deflections for butter-carotenoid solutions at wave lengths 5600 and 6000Å. The deflections (I) for the control cell are recorded in the last column. Data presented in Table I show that turbidity caused sufficient scattering of light to account for the anomalous absorption coefficients presented in Graph 1. Hogness, et al. 8 have published the molecular absorption coefficients for ferriheme cyanide (Table III). Although the data in Tables II and III are for different kinds of substances, the variations of the percent error are in good agreement. From the view point of practical spectrophotometry, it is important to recognize that a 1 % impurity on weight basis may introduce a 10% error in absorption coefficients, especially if the coefficient is very small.