Postmortem detection of methylphenidate [ritalin] in different tissues and organs of rats

In this study, methylphenidate [Ritalin] was detected and estimated in postmortem specimens at different time intervals after treatment of rats with a single toxic dose of the drug Albino Wistar rats of both sexes were injected with Ritalin I.P in a dose of 170 mg/kg.The animals were then divided into 2 groups. Rats of group A were sacrificed 30 min after injection and those of group B were sacrificed 3 hours after injection. Ritalin was detected and measured in rat tissues immediately after sacrification and after 2 weeks 2, 4, 6 and 7 months of putrefaction. By means of colour tests, the drug was detected in brain, liver and kidney tissues immediately after sacrification in both groups of animals. Also, the drug was detected in the brain tissue of group A after 2 weeks and in the kidney tissue of group B animals after 2 months of putrefaction. The drug was not detected in the heart and muscle tissues of both groups of animals at all postmortem intervals. In addition, thin layer analysis detected the drug in all tissues immediately after sacrification in both group of animals. The concentration of the drug in the brain tissues as measured by high performance liquid chromatography was found to be higher in group A than in group B animals immediately after sacrification and after 2 weeks of putrefaction. Through the whole interval of putrefaction, the concentration of the drug in kidney tissues was higher in group B and in the liver and heart tissues was similar in both groups. It is concluded that ritalin toxicity can be diagnosed by postmortem detection and measurements of the drug concentration in brain, liver, kidney, heart and muscle in a period less than 7 months after death

Histological study of early and late nephrotoxicity and endothelial cytotoxicity of ionic and non-ionic contrast media

The Structural changes induced by the use of radiopaque contrast media have been investigated using light and electron microscopic techniques. Three groups of adult male rats were used in this study. The first group [n=15] was injected intravenously with urographin in a dose of 0.5 ml/kg body weight. The second group [n=15] was injected with a similar dose of iopamidol. The third group [n=15] served as control. Specimens from the kidney and inferior vena cava were taken after 3,7 and 14 days of injection. Glomerular and tubular changes of the kidney and the endothelium of the inferior vena cava were evident after the use of both types of media. However, the effect was more pronounced and persistent after the use of ionic media. The results indicate that the tubular effect of the ionic media is secondary to its high osmolality and not to its inherent chemotoxicity. On the other hand, a chemotoxic effect on the glomerular epithelial cells [podocytes] is suggested. In addition, ischemia of the kidney is another factor that contributes to the nephrotoxic effect of the ionic media. Contrast media influenced the endothelium of the inferior vena cava indicating that the effect on the vascular endothelium extends to involve vessels distant from the site of injection