Altered expression of heat shock proteins in embryonal carcinoma and mouse early embryonic cells.

In a previous paper, we have shown that in the absence of stress, mouse embryonal carcinoma cells, like mouse early embryo multipotent cells, synthesize high levels of 89- and 70-kilodalton heat shock proteins (HSP)(O. Bensaude and M. Morange, EMBO J. 2:173-177, 1983). We report here the pattern of proteins synthesized after a short period of hyperthermia in various mouse embryonal carcinoma cell lines and early mouse embryo cells. Among the various cell lines tested, two of them, PCC4-Aza R1 and PCC7-S-1009, showed an unusual response in that stimulation of HSP synthesis was not observed in these cells after hyperthermia. However, inducibility of 68- and 105-kilodalton HSP can be restored in PCC7-S-1009 cells after in vitro differentiation triggered by retinoic acid. Similarly, in the early mouse embryo, hyperthermia does not induce the synthesis of nonconstitutive HSP at the eight-cell stage, but induction of the 68-kilodalton HSP does occur at the blastocyst stage. Such a transition in the expression of HSP has already been described for Drosophila melanogaster and sea urchin embryos and recently for mouse embryos. It may be a general property of early embryonic cells.     

Metabolite fluxes across the inner membrane of plant mitochondria — inhibition by phthalonic acid

Transport and oxidation-reduction of citrate, 2-oxoglutarate and oxaloacetate by mitochondria isolated from thermogenic (Arum maculatum, Sauromatum guttatum spadices), green leaf (Pisum sativum) or etiolated (Phaseolus aureus, Helianthus tuberosus) plant tissues was found to be inhibited by phthalonic acid. No inhibition was found for NADH oxidation, glutamate, succinate or glycine transport and oxidation and malate transport. The much greater sensitivity of citrate oxidation to phthalonate inhibition compared with that of 2-oxoglutarate indicated that different carriers were involved, neither of which appeared to be rate-limiting for oxidation. Fluxes of oxaloacetate, and their sensitivity to phthalonate, indicated that this keto acid may use either the same carrier as 2-oxoglutarate or an oxaloacetate-specific carrier.Abbreviation PTA phthalonic acid     

Determination by capillary gas liquid chromatography of nitrosamine in partially altered food

The nitrosamines have been extensively studied for their toxicity. Their formation in the foods containing nitrous and nitric derivatives is favoured by the presence of suitable substrata. In the present work have been used column and capillari GL Chromatography for the determination of some nitrosamines in altered foods. The results obtained by applying the suggested procedure to a number of altered samples have been very encouraging.     

α-Thalassemia among sickle cell anemia patients in various African populations

Summary We have studied the incidence of -thalassemia in normal and SS individuals from Senegal, Benin, Upper Volta, and Central Republican Africa. The thal gene frequency is not significantly different in the controls from the various populations and in the SS patients from Senegal. In contrast it is compatible with increased survival of SS patients in Benin, Upper Volta. The data suggest epistatic effects of other factors in the Senegalese population.     

Localization of triphosphoinositide in the cochlea

Summary Triphosphoinositide (TPI) has been demonstrated to be a receptor for aminoglycosides in the cochlea and may regulate ionic permeability by its binding with Ca⁺⁺. This phospholipid was localized by a protein A-gold technique in the cochlea at the electronmicroscopic level. TPI was prepared by a neomycin column and antibodies to it were raised in rabbits. The antibody used in this study reacted virtually only to TPI among the tested lipids. TPI was localized mainly at stereocilia, cuticular plates, head plates of Deiter's cells, plasma membrane, and mitochondria of various cells in the organ of Corti. In the vascular stria, TPI was found mainly at the plasma membrane of basal infoldings of the marginal cells. Possible physiological and pathophysiological roles of TPI in the cochlea are briefly discussed.     

Homologous radioimmunoassay of a hypothalamic factor stimulating salmon pituitary gonodatropic function (sGnRH)

A radioimmunoassay for Salmon Gn-RH p-gly-His-Trp-Ser-Tyr-Gly-Trp- Leu-Pro-Gly) (NH2) has been developed with a sensitivity of 7 pg/assay tube. The system allows the specific detection of an immunological GnRH related substance in the brain and pituitary of three teleost species but not in an elasmobranch the Dogfish. these results are discussed and some Gn-RH contents of the organs are proposed.     

Growth hormone releasing factor: comparison of two analogues and demonstration of hypothalamic defect in growth hormone release after radiotherapy.

Human pancreatic growth hormone releasing factor (hpGHRF(1-40] stimulates the release of growth hormone in normal subjects and some patients with growth hormone deficiency. A study comparing the shorter chain amidated analogue hpGHRF(1-29) with an equivalent dose of hpGHRF(1-40) in seven normal subjects showed no significant difference in growth hormone response between the two preparations. Six patients with prolactinomas were also tested; these patients had received megavoltage radiotherapy previously but had developed growth hormone deficiency as shown by insulin induced hypoglycaemia. In all six patients 200 micrograms hpGHRF(1-40) or hpGHRF(1-29)NH2 produced an increase in the serum growth hormone concentration. These data suggest that hpGHRF(1-29)NH2 may be useful for testing the readily releasable pool of growth hormone in the pituitary and that cases of hypothalamo-pituitary irradiation resulting in growth hormone deficiency may be due to failure of synthesis or delivery of endogenous GHRF from the hypothalamus to pituitary cells.