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Z Ruben

Publications and source records attributed to Z Ruben.

22 records · Page 2Linked to original sources
PubMed1983

Esophageal impaction in BHE rats.

Spontaneous esophageal impaction was observed in 33 BHE rats, aged 6 to 26 months, from 157 rats which died or were killed when moribund due to spontaneous conditions. The clinical course lasted less than 48 hours and included weakness, excessive salivation, forward head motions, matting of chin and perioral hair with bedding material, followed by recovery or death. In some animals, the clinical episodes reoccurred. The esophagus was dilated (up to 7.0 mm) and impacted with bedding or food. The caudal half of the esophagus was affected more than the cranial half. The esophageal muscle was thin and pale at the site of impaction. Histologically, there was esophageal myodegeneration.

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Strain as a determinant factor in the differential responsiveness of rats to chemicals.

The beneficial effects derived from the use of chemicals in agriculture, energy production, transportation, pharmaceuticals, and other products that improve the quality of life are clearly established. However, continued exposure to these chemicals is only advantageous in conditions where the benefit far outweighs toxic manifestations. By law, determination of risk of toxicity necessitates the use of laboratory animals to establish whether chemical exposure is safe for humans. To simulate the human condition, it is incumbent upon investigators to choose a species in which pharmacokinetic and toxicokinetic principles are established and resemble those of humans. Some of the advantages to the use of rat in chemical toxicity testing include (a) similarities in metabolism, anatomy, and physiological parameters to humans; (b) the short life span, especially for carcinogenesis study; (c) the availability, ease of breeding, and maintenance at a relatively low cost; and (d) the existence of a large database to enable comparison of present to reported literature findings. However, the choice of rat can be complicated by several factors such as sex, age, and nutrition, but especially strain, where currently there are over 200 different strains of rat known to exist. The aim of this review is to demonstrate that there are differences in the responsiveness of rat strains to chemicals and that the susceptibility observed is dependent on the tissue examined. It is evident that the genotype differs among strains, and this may be responsible for differences in sensitivities to chemicals. Awareness of strain as a factor in susceptibility to toxicant action needs to be taken into account in interpretation of relevance of risk of toxicity for humans.

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