Treatment of meats with ionising radiations. XV.—Irradiation of beef from barley-fed animals

Joints of ‘barley beef’, irradiated at a dose level of 0.4 Mrad., were stored at 2° in plastic packages of differing gas permeabilities. Bacterial growth was reduced by the lack of oxygen and/or the accumulation of carbon dioxide. The irradiated meat remained unspoiled for at least 84 days. The useful shelf-life of the beef can be extended greatly by irradiation, but the undesirable colour changes resulting from the exclusion of oxygen remains a serious drawback.     

An experimental determination of the carrier lifetime near the SiSiO2 interface

Leakage currents in phosphorus-gettered (111) silicon have been studied at room temperature using a MOS gate-controlled diode structure. The leakage current and the gate-substrate capacitance have each been measured as a function of gate voltage for different values of reverse bias. From these measurements the carrier lifetime in the depletion region near the SiSiO₂ interface has been deduced. It is found that the lifetime decreases with distance from the interface; an explanation for this is suggested.     

The carcinoid endocardial plaque; an ultrastructural study

Ultrastructural studies disclosed that the plaque-like endocardial thickenings in three patients with the carcinoid syndrome were composed of smooth muscle cells embedded in a stroma that was rich in acid mucopolysaccharides, collagen, and microfibrils, but devoid of elastic fibers. The smooth muscle cells contained variable numbers of myofilaments and cisterns of rough surfaced endoplasmic reticulum, and their basement membranes were greatly thickened, reduplicated, and arranged in layers. The endocardial plaques appeared histologically and ultrastructurally similar regardless of their location in the heart. The smooth muscle cells in these plaques appear to have been derived from primitive mesenchymal cells, which normally are present in the subendocardial endothelial space. These observations are interpreted as indicating that the plaques develop as a result of healing of a superficial endocardial injury, which may be initiated by release of bradykinin from hepatic metastases of a carcinoid tumor.     

Brain areas controlling thermoregulatory grooming prone extension, locomotion, and tail vasodilation in rats.

In an experiment with 134 male Long-Evans rats, localized diathermic warming elicited the principal hyperthermic responses of the rat: grooming, body extension, locomotion, and tail vasodilation. Failure of diathermy to elicit nonthermoregulatory responses evoked by electrical stimulation ruled out nonspecific excitation. The largest zone extended from the septal area through the preoptic area and hypothalamus into the midbrain, and a smaller zone was located in the medulla. Grooming, extension, and locomotion were obtained from differentiated though partially overlapping subareas, all of which elicited vasodilation. Fewer than 3% of the electrodes induced all responses, while the remainder produced incomplete combinations, indicating that the rat's hyperthermic repertoire results from largely independent channels from thermal detector to motor effector, and does not require an integrative center or mutually excitatory collaterals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Growth depression and tissue reaction to the consumption of excess dietary methionine and S-methyl-L-cysteine

Similar depressions in growth were observed when rats consumed a 10% casein basal diet containing equal quantities of either methionine or S-methyl-L-cysteine. Supplemental glycine or serine partially alleviated the growth depression caused by the high levels of methionine but were ineffective in alleviating the growth depression caused by high levels of S-methylcysteine. Histological examination of five organs of rats fed the basal, high methionine or high S-methylcysteine diet for 6, 13 or 20 days revealed that only the spleens were affected in that there was erythrocyte engorgement and an accumulation of hemosiderin. The intensity of iron staining in spleens decreased from the second to the third week. The similarity in the depression of growth and splenic damage observed in rats consuming high levels of methionine or S-methylcysteine is consistent with an earlier suggestion that metabolism of the methionine or S-methylcysteine is consistent with an earlier suggestion that metabolism of the methyl group is in some way involved in the toxicity of methionine.