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661.
J Fèvre 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1975,281(24):2009-2012
Foetal and maternal blood samples are taken on the sow at the end of pregnancy. No variations in maternal cortisol are found, but plasma cortisol levels in the foetus, which are relatively constant between days 70 and 100 of pregnancy (10 to 20 ng/ml), increase suddenly at the end of pregnancy reaching a mean of 210 ng/ml at birth. This high increase of foetal corticosteroids at birth, similar to that found in other species (ewe, goat, etc.), probably plays a role in the mechanisms releasing parturition. It also permits us to understand the action of ACTH which induces premature birth when given to the pig foetus in the last days of pregnancy. 相似文献
662.
The first synapse in the vertebrate visual system is made between the photoreceptors and the biopolar cells. Bioplar cells fall into two distinct classes according to whether the cell hyperpolarizes or depolarizes to small centred spots of light. Most evidence indicates that the light-induced hyperpolarization of the photoreceptprs suppresses transmitter release from the synaptic terminals, and it is probable that the differences between the two bipolar cell classes results from the different actions of the photoreceptor transmitter. In analysing the membrane potential fluctuations in both types of bipolar cell we find that the voltage noise spectra differ. It is to be expected that postsynaptic noise would be composed of the sum of noise generated in and transmitted from the cones and the noise arising from the statistical nature of synaptic transmission. We report here evidence for two such components in the voltage noise spectra recorded from each type of bipolar cell. The differences in the frequency distribution of the presumed transmitter-related components indicates that the transmitter generates events of longer duration in the depolarizing biopolar cells. 相似文献
663.
D F Veber F W Holly R F Nutt S J Bergstrand S F Brady R Hirschmann M S Glitzer R Saperstein 《Nature》1979,280(5722):512-514
664.
G Albiser M Brice P Horn A Larcan J F Stoltz 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1977,284(12):1107-1109
An X-ray diffraction study has been undertaken on Human and Rabbit blood-vessels. Vessels are stretched 500% and the diagrams present a great analogy with those obtained from collagen. Thus, it appears, that it is possible to determine by X-Rays some pathological anomalies of the collagen in vessels. 相似文献
665.
666.
667.
668.
F. Kaiser 《Cellular and molecular life sciences : CMLS》1965,21(10):575-575
Summary The primary glycosides, glucodigifucoside and neo-glucodigifucoside, were isolated from the extract ofDigitalis lanata leaves. They are isomeric glucosides of digiproside and differ in the position of attachment of thed-glucose residue. Digitoxigenin-allomethylosid was isolated from the leaves after enzymatic decomposition.
23. Mitteilung über Herzglykoside; unter der ausgezeichneten experimentellen Mitarbeit vonH. Gerlach. 相似文献
23. Mitteilung über Herzglykoside; unter der ausgezeichneten experimentellen Mitarbeit vonH. Gerlach. 相似文献
669.
Summary The investigation of the taste buds in the tongue of the neotene Mexican axolotl (Siredon mexicanum) by light and electron microscopy demonstrates 4 different cell types: 1) R-cells, marginal cells of less differentiated character. 2) G-cells, granulated cells in basal position. 3) Cells of type A with fibrills, vesicular elements, and dark bodies, showing supporting and secretory function. 4) Cells of type B with an agranular endoplasmic reticulum in stripe like arrangement, supposed to be receptor cells. 相似文献
670.
Speer RJ Garton WR Morgan JF Nicholls RW Goldberg L Parkinson WH Reeves EM Jones TJ Paxton HJ Shenton DB Wilson R 《Nature》1970,226(5242):249-250
Flash spectra of the total solar eclipse throughout all its phases have been obtained in the extreme ultraviolet for the first time. 相似文献