Simplified Aldehyde-Fuchsin Staining of Neurosecretory Cells

Gomori's original aldehyde-fuchsin method has been modified by the combination of Halmi's counter stain with Gabe's preparation, consisting of basic fuchsin, 1 gm; boiling water, 200 ml; with HC1, 2 ml and paraldehyde, 2 ml added after cooling and filtering. The solution so made was allowed to ripen 3-4 days at room temperature, and the precipitate which formed was filtered off and dried at 55-60°C. The staining solution consisted of 0.5 gm of the dry precipitate dissolved in 100 ml of 70% alcohol. The staining follows original procedures except that it is very important to bring slides from water to 70% alcohol before placing them in the aldehyde-fuchsin solution and also to remove all excess staining solution by rinsing in 95% alcohol after staining. The staining solution is stable for at least 6 mo.     

In-vivo studies of mammary development in the goat using magnetic resonance imaging (MRI)

Mammary development and regression were measured in goats in vivo using magnetic resonance imaging (MRI). Measurements were made during the first and second cycles of pregnancy, lactation and involution. In primiparous goats, and exponential pattern of growth was evident during gestation and for the first 2 weeks of lactation. Parenchyma volume correlated significantly with milk yield across goats during early lactation, and across stage of lactation within goats. Milking was discontinued in Week 26 of the first lactation. Involution was characterized by an initial accumulation of fluid (over 2 days) followed by reabsorption; parenchyma volume did not decrease significantly until the 3rd week of involution, which was also the time at which these goats were mated to start their second gestation. Their udders still contained significant quantities of fluid (40-60% of the gross volume), but parenchyma volume was also greater (by 4.7-fold) than in goats beginning their first gestation. By Week 15 of gestation there was no longer a parity difference in parenchyma; the udders of first-gestation goats had grown significantly, but those of second-gestation goats had not. Conversely, between gestation Week 15 and lactation Week 2 mammary growth was significantly more rapid in the second cycle, such that the udder was larger at the start of the second lactation.     

Supra-additive stimulation of adenylate cyclase activity by prostaglandin E2 andD-Ala2-met-enkephalinamide in the guinea-pig superior cervical ganglion: Role of Mg2+ ions

Agonists modulation of Mg²⁺-dependent adenylate cyclase activity has been studied in guinea-pig superior cervical ganglion crude membrane preparations. In the absence of receptors ligands, Mg²⁺ stimulates the enzyme in a concentration-dependent manner. The dose-activation curve shows heterogeneity and two components with higher and lower apparent affinity states, are extrapolated. In the presence ofD-Ala²-met-enkephalinamide only one component is present and the apparent affinity of the ganglionic adenylate cyclase system for the divalent cation as well as Vmax are inhibited. On the contrary, prostaglandin E₂ increases affinity and Vmax values of the lower and, to a lesser extent, of the higher Km component. When the two drugs are tested in combination, not only the inhibitory effect of the opiate is overcome, but a large increase of the apparent affinities and Vmax values for both components is obtained, suggesting the involvement of the Mg²⁺-regulated subunits of the adenylate cyclase system in the supra-additive stimulation mechanism of the enzyme.     

Effects of brain ischemia on intermediate filaments of rat hippocampus

Neurofilaments subunits (NF-H, NF-M, NF-L) and glial fibrillary acidic protein (GFAP) were investigated in the hippocampus of rats after distinct periods of reperfusion (1 to 15 days) following 20 min of transient global forebrain ischemia in the rat. In vitro [¹⁴Ca]leucine incorporation was not altered until 48 h after the ischemic insult, however concentration of intermediate filament subunits significantly decreased in this period. Three days after the insult, leucine incorporation significantly increased while the concentration NF-H, NF-M, and NF-L were still diminished after 15 days of reperfusion. In vitro incorporation of³²P into NF-M and NF-L suffered immediately after ischemia, but returned to control values after two days of reperfusion. GFAP levels decreased immediately after ischemia but quickly recovered and significantly peaked from 7 to 10 days after the insult. These results suggest that transient ischemia followed by reperfusion causes proteolysis of intermediate filaments in the hippocampus, and that proteolysis could be facilitated by diminished phosphorylation levels of NF-M and NF-L.