襁褓中的球状星团

在银河系中藏有早期宇宙的化石中,其中在银晕中大约有150个球状星团,它们差不多和宇宙同龄。不仅仅是银河系,在其他大质量星系中球状星团也是无处不在。球状星团有极大的质量和极高的密度,因     

Epithelial cell processes in the development of the secondary palate in the mouse

Summary Ultrastructural studies of palatal shelves of Tuck A mice embryos aged 12.25–14.25 days show discontinuities of the epithelial basement membrane traversed by epithelial cell processes before the onset of midline degenerative changes.     

Measurement of urinary steroid production rates using stable-isotopes and GC-MS

Summary The urinary production rate of pregnenolone has been determined for a male subject using 7,7-d₂-pregnenolone as an isotopic tracer.To whom correspondence should be addressed.     

Inactivation of yeast glucose-6-P dehydrogenase by aspirin

Summary Glucose-6-P dehydrogenase is irreversibly inactivated by treatment with Na salts of aspirin. Kinetic data show that 1 molecule of aspirin reacts with each active unit when the enzyme is inactivated. The rate of inactivation is enhanced with increasing pH but is reduced in the presence of glucose-6-P or NADP⁺. Na salicylate fails to inactivate the enzyme.This work was supported by grant RR-8006 from the General Research Branch, Division of Research Resources, NIH (USA).     

Functional consequences of treating turkey liver fructose-1,6-bisphosphatase with penicillin G

Summary Treatment of turkey liver fructose-1,6-bisphosphatase with penicillin G progressively inactivated the enzyme and desensitized the enzyme toward high substrate inhibition. The treatment also led to reduced sensitivity to AMP inhibition and the loss of cooperative interaction among AMP-binding sites. These altered properties were not reversed by dialysis, but were prevented when treatment with penicillin G was performed in the presence of substrate.This work was in part supported by grant RR-8006 from the General Research Branch, Division of Research Resources, NIH (USA) and in part by Faculty Research Grant from Southern School of Pharmacy, Mercer University, Atlanta (Georgia, USA).     

Soft versus hard water as a factor in the incidence of anencephalic foetuses in litters from trypan blue treated mice

Summary In an experiment designed to test the possible correlation between hard water and neural tube anomalies, high calcium intake was found to increase the number of exencephalic foetuses in litters from trypan blue treated mice. This is a reversal of the suggested trend in man where soft water and anencephaly may be correlated.     

Alternative methods of animal sacrifice: The effect on intestinal function in vitro

Summary The total fluid uptake of everted sacs of rat jejunum was compared in animals killed by stunning and decapitation, or anaesthetised with ether. Fluid transport was significantly higher in the tissue prepared from stunned and decapitated animals. It is suggested that etherization may have adverse effects on the physiological viability of subsequently isolated tissues.