A morphometric study of the carotid body in chronically hypoxic rats

We performed morphometric studies of carotid body in acutely and chronically hypoxic rats (inspired PO2 = 70 Torr, at sea level). Acute exposure was for the duration of about 10 min, and chronic exposure lasted for 28 days. We confirmed that the total volume of the organ increased by severalfold. At the light-microscopy level we found an enlargement of the volume density of the blood sinuses from 14 to 31% due to chronic hypoxia. The morphometric hematocrit increased from 39 to 70% paralleling changes in the conventionally measured venous hematocrit. These data do not show any specific plasma skimming in the carotid body blood vessels. With the electron microscope we found that the mean average volume of type I cells increased from 320 micron3 in controls to 1,120 micron3 in the chronically hypoxic rats without hyperplasia, whereas type II cells had increased in number without alteration in size. Qualitative observations revealed that the normal appearance of clusters of ovoid type I cells interspersed by capillaries had been transformed into a pattern of individual cells forming plates between expanded blood vessels with a large increase of contact area between the cells and vessels. Type II cells appeared to have proliferated without changes in individual size to cover the enlarged periphery of type I cells. The observed structural changes in the carotid body parenchyma and vasculature appear to be physiologically adaptive and provide further support for the idea that various elements in the organ are particularly sensitive to hypoxia.     

Effect of commercial processing of canola and rapeseed on growth of larvae of the yellow mealworm, Tenebrio molitor L

Larvae of Tenebrio molitor L., Gembloux strain, race F, were used to determine the nutritional quality of commercial canola and rapeseed products. Application of heat in commercial processing increased considerably the nutritive values of Midas, Tower and Torch cultivars, and to a lesser extent that of Candle. This improvement was most noticeable for thigh-glucosinolate cultivars, presumably through the destruction of a mechanism for production of isothiocyanates that may be phagodeterrent or toxic to the larvae. For low-glucosinolate varieties, the improvement may be related to inhibition of nitrile production in heated material. The processing also reduced the concentration of available lysine in the products of all four cultivars; however, growth was unimpaired by this reduction. The latter results suggest that the feed products resulting from processing may exceed the optimal dietary requirement of lysine by larvae of Tenebrio molitor.     

Trans-ethnic variation in germline variants of patients with renal cell carcinoma

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