Separation by gel chromatography of naturally occurring phosphatidylcholine mixtures according to number of ethylenic linkages

This paper describes a procedure for the separation of lecithins according to the number of ethylenic bonds in their fatty acid residues. The procedure uses a column of alkylated dextran (Sephadex LH-20) eluted with an organic solvent system, the unsaturated lipids being separated as their mercuric acetate addition compounds. The system is capable of resolving at least four species of lecithin, and the intact lecithin molecules can be recovered for further study. The chromatographic system has been tested with lecithin derived from dog lung, rat liver, and hen's egg.

Enzyme activity, acidic nuclear proteins, and prognosis in human breast cancer

The activities of the enzymes lactate dehydrogenase, 6-phosphogluconate dehydrogenase, and phosphohexose isomerase in primary human breast cancer biopsies are shown to be related to the time between mastectomy and recurrence of the cancer. These enzymes have higher activity in malignant breast tissues generally than in non-malignant breast tissues. In tumours from patients with long free periods these differences are not apparent.Evidence is presented which suggests that two different types of breast cancer can be distinguished according to the relative amounts of phosphohexose isomerase and acidic nuclear proteins. It is suggested that this difference may be related to hormone responsiveness.

Some applications of thin films to polarization devices

In the first application of thin films discussed, a multilayer stack is enclosed in a cemented cube to form a polarizing beam splitter. Polarizing efficiencies exceeding 99.8% have been achieved in both reflected and transmitted beams at the design wavelength. In the second application, the deposition of thin films on the totally reflecting surfaces of silica phase retarding systems has resulted in a substantial improvement in achromatism of these devices. Measured phase retardations of one of the two devices described were within 0.5 degrees of 90 degrees over the visible and uv to wavelengths down to 200 nm.

The properties of a nuclear acidic protein fraction that binds [6,7-3H]oestradiol-17beta

1. Additional evidence was obtained that the nuclear oestradiol-17beta receptor is an acidic protein. Partial purification of the receptor protein was obtained by chromatography on hydroxyapatite and it contains protein-bound phosphate. 2. The nuclear ;5s' and cytoplasmic ;9.5s' and ;5s' receptors from uterus, dimethylbenzanthracene-induced mammary adenocarcinoma and kidney are precipitated together with bound oestradiol-17beta by protamine sulphate. This common property suggests that the nuclear and cytoplasmic receptors are related to each other. 3. The properties of two acidic protein fractions from both liver and dimethylbenzanthracene-induced mammary adenocarcinoma are described. Fraction 1 contains two major components and fraction 2 contains one component, as judged from polyacrylamide-gel electrophoresis. Fraction 2 contains RNA and both fractions contain protein-bound phosphate. 4. These fractions form insoluble complexes with calf thymus histone, protamine sulphate and poly-l-lysine. The formation of these complexes is markedly affected by ionic strength and pH. Ionization of both the in-amino group of lysine and carboxyl group are involved. RNA and DNA do not appear to be involved. The interaction is not affected by EDTA or 1mm-Na(+), -K(+), -Ca(2+), -Mg(2+) or -Mn(2+). Per unit weight, whole histone has 4-5 times as many binding sites for the acidic proteins as the latter have for the former. 5. No convincing evidence was obtained for DNA-acidic protein interaction, but, as judged from precipitation experiments, there was competition between DNA and acidic protein for histone. 6. Relatively large amounts of acidic protein partly relieved the histone inhibition of the template activity of DNA for Escherichia coli RNA polymerase (EC 2.7.7.6).

The location of (6,7-3H) oestradiol-17-beta in mouse vagina

The retention of [6,7-3H]oestradiol-17β in fractions of the mouse vagina has been studied after direct application of 50 pg. of this oestrogen. Tritium was present in both epithelial and stromal cells. Most of the tritium was associated with the nuclear fraction from the epithelium. The nuclear binding was acid labile and only 30% of the nuclear tritium was extracted with 2 m-NaCl. The results obtained by sonic disruption of the nuclei were compatible with the view that the [6,7-3H]oestradiol-17β was associated with chromatin.

No evidence was obtained for the presence of a cytoplasmic oestradiol-binding component in the epithelium.

An attempt to isolate an oestradiol receptor from nuclei by adsorption on oestradiol-17-beta

The binding of nuclear proteins from dimethylbenzanthracene (DMBA)-induced rat mammary tumours and other natural and synthetic proteins to columns of oestradiol-17β (oestradiol) has been studied. A wide range of proteins, but not DNA, bind to oestradiol under these conditions and this binding is disrupted by acid. Both histone and acidic nuclear protein fractions bind to oestradiol and the bound fraction had, in both cases, the ability to bind [6,7-3H]oestradiol. Acrylamide gel electrophoresis showed that more than one protein from both the acidic and basic nuclear protein fractions was bound to the oestradiol. More poly-l-glutamic acid and poly-l-glycine was bound to the oestradiol than poly-l-lysine. Oestradiol columns bound more protein from both the histone and acidic protein fraction than did columns of oestrone. Oestradiol bound more acidic protein than testosterone or progesterone but this difference was not evident with the histone fraction.

Equilibrium dialysis experiments showed that the ability of a protein to bind to oestradiol was not related to its association constant with [6,7-3H] oestradiol.

The acidic nuclear proteins had a higher association constant than the histone fraction.

These results are discussed in relation to the purification of oestradiol receptors and to the binding of [6,7-3H]oestradiol in vivo.

The association of [6,7-3H]oestradiol with a nuclear protein

The binding of [6,7-3H]oestradiol to nuclei from rat dimethylbenzanthracene-induced (DMBA) mammary tumour, uterine epithelium, anterior pituitary and kidney has been studied. Digestion of nuclei labelled in vivo with [6,7-3H]oestradiol, with RNase, DNase and trypsin indicated that only the last enzyme released tritium from the nucleus, indicating that the receptor is a protein. The optimal concentration of sodium chloride for extracting the oestradiol-receptor complex from tumour nuclei was 1-molar. This concentration was required even after enzymic removal of most of the DNA and RNA. Sodium deoxycholate also extracted oestradiol from nuclei but at the same time dissociated the oestradiol-receptor complex. An attempt was made to fractionate the oestradiol-receptor complex on Sephadex and Biogel columns.

The uptake of [6,7-3H]oestradiol by the normal human female reproductive tract

The uptake of [6,7-3H]oestradiol by the reproductive tract was studied in 18 non-pregnant women who were undergoing hysterectomy for conditions not associated with an abnormal endometrium. A single s.c. injection of 50 μc [6,7-3H]oestradiol (specific activity, 182 μc/μg.) was given 2 hr. before hysterectomy. Tissue samples were dissolved in 5 n-alkali and their radioactivity content determined by liquid scintillation counting. Total and free steroid (ether soluble) radioactivities in the plasma were also determined. The existence of an essentially normal menstrual cycle in these patients was confirmed by histological examination of tissue samples and, in some cases, by determinations of urinary pregnanediol. Urinary total radioactivity was within the normal range, except in one case, thus confirming normal oestrogen metabolism.

The radioactivity content of the tissues of the reproductive tract was well above that attributable to their plasma content. In some cases the uptake by different regions of the endometrium varied considerably. In the follicular phase of the menstrual cycle uptake was higher than that in the luteal phase. Vaginal and cervical epithelium showed variable uptake but in general it was lower than that for endometrium.

Cell fractionation studies showed that, in general, proportionally more of the endometrial radioactivity was associated with the nuclei in the follicular phase than in the luteal phase.

The uptake and localization of [6,7-3H]oestradiol-17-beta in tissues of male Syrian hamsters

The uptake, metabolism and intracellular localization of [6,7-3H]oestradiol-17β in male hamster kidneys and liver have been studied. Three doses of [6,7-3H]oestradiol were injected, and tissues were removed 30 min. and 4 hr. later. The tissue radioactivity was separated into 'free', 'glucosiduronide', 'sulphate' and 'polar' fractions. Most of the radioactivity was associated with the 'polar' fraction. Oestrone and oestradiol were identified in liver and kidney. Cell fractionation showed that most of the radioactivity was in the 'soluble' fraction. Neither the amount of [6,7-3H]oestradiol injected nor the time after injection at which the tissues were taken affected the metabolites or their intracellular location.