A Simplified Method for Staining Mast Cells with Astra Blue

The copper phthalocyanin dye astra blue has been used to stain differentially mast cells of the intestine; however, the procedure has not been used widely because of the difficulty in preparing and using the dye solution. Described here is a simple, reliable, and consistent method for selectively staining mast cells using a dye solution that may be prepared in any laboratory without the aid of sophisticated pH metering equipment. Astra blue is mixed with an alcoholic solution containing MgCl₂ · 6H₂O and the pH indicator pararosaniline hydrochloride. Concentrated hydrochloric acid is added dropwise, changing the dye mixture from purple to violet and then to blue. In this low range the weakly ionizing ethanol provides a more stable hydrogen ion concentration than the corresponding aqueous solutions used previously. Alcoholic acid fuchsin is a convenient counterstain, and this simple procedure then provides good contrast between the blue staining mast cell granules and the red tissue background.     

Habitat choice in natural populations of Drosophila

Summary Mark-release-recapture experiments performed with natural populations of Drosophila at Mather, California show that flies tend to return to their area of original capture or an area ecologically similar to it. Such habitat choice explains the microgeographic genetic differentiation we observed in the population. This behavioral difference between the flies may have a genetic component or may be environmentally induced. Either way, the results help explain how high levels of genetic variation are maintained by natural selection in these species.     

Goiter in Tibetan Medicine

The visit of two Tibetan physicians provided a unique opportunity to gain insight into a practice of medicine very different from that of Western civilization. Initial discussions indicated that the practice of medicine and mysticism were inextricably interwoven in the Tibetan culture. Accordingly, the focus of the study was directed to goiter, which is both common in the Himalayas and easy to define.In Tibetan medical practice, illness is considered to be derived from both proximate and distant causes. Three humors, “wind,” “bile,” and “phlegm” are thought to be responsible for normal mental and physical functions when in balance, but disease when out of balance. Goiter was thought to be due to an imbalance of these humors. The Western discovery that endemic goiter in the Himalayas was due to iodine deficiency explained the proximate cause but did not explain why some individuals have goiter and others do not in the same iodine deficient village.     

Activation of α-1 adrenergic receptors modulates the control of left/right sidedness in rat embryos

Presomite stage rat embryos were cultured for 45–49 hr with medium containing various adrenergic agonists and antagonists. -Norepinephrine but not -norepinephrine (several orders of magnitude less potent than the -isomer at α-1 adrenergic receptors) resulted in a dose-dependent increase of situs inversus similar to that found for phenylephrine, an α-1 adrenergic agonist. Prazosin, an α-1 adrenergic antagonist, inhibited phenylephrine-induced situs inversus in a dose-dependent manner. Neither dexmedetomidine, an α-2 adrenergic agonist, nor isoproterenol, a β adrenergic agonist, caused situs inversus. These results provide pharmacological evidence that stimulation of α-1 but not of α-2 and β adrenergic receptors modulates the control of left/right sidedness in rat embryos.     

Differential plating medium for quantitative detection of histamine-producing bacteria.

A histidine-containing agar medium has been devised for quantitative detection of histamine-producing bacteria that are alleged to be associated with scombroid fish poisoning outbreaks. The responsible bacteria produce a marked pH change in the agar, with attendant color change of pH indicator adjacent to the colonies, thus facilitating their recognition. Proteus morganii and Klebsiella pneumoniae were the two most common histidine-decarboxylating species isolated from scombroid fish and mahi mahi.     

Greatly extended viability of rat brain storage vesicles in an intracellular medium based upon a non-permeant polyanion

The MgATP-stimulated accumulation of (-)-³H-nor- epinephrine (NE) by rat brain neuronal storage vesicles has been characterized in a new medium based upon polyacrylic acid (avg. MW 5,000). The medium allows careful regulation of K⁺ concentration (140 mM), has a large buffer capacity, and is non-permeant to membranes. Light scattering measurements have confirmed the osmotic stability of vesicles suspended in this medium. Vesicular accumulation of (-)-³ H-NE (Km 1 × 10^?6 M) in this system (37°) was examined under saturating (10^?5 M) and non-saturating (2 × 10^?7 M) concentrations of NE. At 10^?5 M NE, uptake saturated at 5 min and remained stable for periods up to one hour, with maximal uptake levels (pmol/mg protein) of 15.7±0.30 (37°), 3.0±0.49 (0°), 4.4±0.22 (reserpine pretreated $\text{in}$$\text{vivo}$) and 6.0±0.79 (without MgATP). At 2×10^?7 M NE uptake was biphasic with maximal uptake levels (pmol/mg protein) of 4.04±0.14 (37°), 0.19±0.01 (0°), 0.95±0.01 (reserpine) and 0.83±0.08 (without MgATP). Vesicle preparations refrigerated in this medium for 24 hrs displayed properties quite similar to those measured acutely (NE = 2.2x10^?7 M).