Differences in growth response to hydrocortisone and ascorbic acid by human diploid fibroblasts

Summary The effects of hydrocortisone and ascorbic acid on growth parameters were measured in human diploid skin fibroblasts from fetal and adult donors. In the presence of culture medium containing 10% fetal bovine serum, 0.3 μM hydrocortisone produced a 20% increase in the population growth rate and a 50 to 70% increase in the confluent density of fibroblasts from adult donors. Daily addition of 28 μM ascorbic acid also stimulated the population growth rate and cell density at confluency. The effects of hydrocortisone and ascorbic acid on the final cell density were additive. The action of hydrocortisone was restricted to cells in log-phase growth, whereas ascorbic acid affected cells in both the log and the postconfluent phases of the growth cycle. In fibroblasts from fetal donors, ascorbic acid was stimulative but hydrocortisone was not. The data suggest that whereas both compounds stimulate cell growth in an additive manner, they do so by different cellular mechanisms. This investigation was supported in part by USPHS Grants AM 02456, AM 05020 and AM 15312, and by the Kroc Foundation, No. UW 63-2986. Dr. Rowe is a fellow of the Helen Hay Whitney Foundation. Dr. Fujimoto is a recipient of a Research Career Development Award, AM 47142, from NIAMDD.     

Cold pressor test in diagnosis of coronary artery disease: echophonocardiographic method.

The cold pressor test was used to induce myocardial ischaemia in patients with coronary artery disease and the rise in left ventricular filling pressure used as the index of myocardial ischaemia. Left ventricular filling pressure was derived from a non-invasive echophonocardiographic method. A study group of 19 consecutive patients with chest pain underwent the cold pressor test before coronary angiography. Eighteen responded with a rise in filling pressure exceeding 30% and, of these, 17 had serious coronary artery disease (three single vessel, one two vessel, and 13 triple vessel disease; one had coronary artery spasm only). The remaining patient, who showed no rise in filling pressure, did not have coronary artery disease. None of 15 normal controls showed a rise greater than 5% (patients with coronary artery disease versus normal controls p less than 0.001). The cold pressor test would be suitable for patients who cannot or should not exercise and may be combined with exercise electrocardiograms to improve the information content, as it uses a different marker of myocardial ischaemia.     

Distribution of Na+, K+-ATPase α-Subunit Isoforms in Rat Pituitary

The distributions of alpha-subunit isoforms of the Na+,K(+)-ATPase in rat pituitary were determined by immunoblotting and immunohistochemistry. Immunoreactivity for all three forms is present in the neural lobe, whereas the anterior lobe contains only alpha 1 and alpha 2. Most areas of the intermediate lobe exhibit faint immunoreactivity for only alpha 1, but thin strands of cells which stain strongly for all three isoforms are also present in this lobe. The previously reported ouabain inhibitable Na+,K(+)-ATPase activity in the neural lobe is consistent with the presence of both alpha 2 and alpha 3 subunits.     

Ets-1 and Ets-2 protooncogene expression in theca cells of the adult mouse ovary.

We have investigated the mRNA expression of the Ets-1 and Ets-2 genes in murine gonads and found expression in adult ovaries. In situ hybridization experiments show that the Ets genes are predominantly expressed in theca cells and cells of ovarian interstitium. By gel retardation experiments we detected DNA binding proteins in ovaries that specifically bind to the ETS motif, suggesting the expression of Ets or Ets-related proteins. Our results raise the possibility of Ets-2 involvement in ovarian pathology seen in patients with Down's syndrome.     

Impact of mild experimental acidification on short term invertebrate drift in a sensitive British Columbia stream

We report daytime drift behavior of lotic macroinvertebrates following short term (12 h) additions of HCl or HCl plus AlCl₃ to a circumneutral softwater (alkalinity ca. 100 µeq 1^-1) mountain stream in British Columbia, Canada. Addition of HCl (pH reduced from 7.0 to 5.9) resulted in an overall tripling of invertebrate drift density with rapid (< 1 h) increases in chironomid Diptera and Trichoptera. Small Ephemeroptera also entered the drift at high densities, but were delayed about 6 h. Addition of AlCl₃ (0.71 to 0.95 mg 1^-1 total Al³⁺) in HCl (stream pH reduced to 5.9) resulted in an overall 6-fold increase in invertebrate drift, with rapid increases by Ephemeroptera and delayed responses by chironomids and Trichoptera. These results suggest that the behavior of several macroinvertebrates from low alkalinity, unacidified streams can be altered by simulations of short-term, mild acidic deposition events. Further, the magnitude and timing of entry into the drift varies among taxonomic groups with the presence or absence of low concentrations of aluminum ions.     

The characterization of growth factor activity in human brain

The purification of fibroblast growth factor from bovine brain has been reported (Gospodarowicz, D., Bialecki, H., and Greenberg, G. (1978) J. Biol. Chem. 253, 3736-3743). Westall et al. (Westall, F. C., Lennon, V. A., and Gospodarowicz, D. (1978) Proc. Natl. Acad. Sci. U. S. A. 75, 4675-4678) showed that bovine brain fibroblast growth factor was composed of three fragments derived by limited proteolysis from myelin basic protein. In the present study using similar purification methods, we isolated a fraction enriched in growth factor activity from human brain. The mitogenic activity could not be resolved from myelin basic protein by chromatographic procedures but, upon isoelectric focusing, the mitogen and myelin basic protein were readily dissociated. At least two potent growth factors (pI values 7.2 to 7.4 and 8.1 to 8.6) were identified. Studies of a relatively crude basic extract of human brain suggested that the brain may contain a number of growth factors.