new bIologIcal model of moderate InhIbItIon of tumor and metastases growth wIth prolonged leukopenIa In mIce

A new biological model of moderate inhibition of tumor growth and metastases with prolonged leukopenia on C57Bl/6 mice with the Lewis Lung Carcinoma was designed. The model was created by the injection of cyclophosphamide (dose 83.3mg/kg) on 6th, 12th, 18th days after tumor cells transplantation on animals. Experiment showed that 3-fold cyclo-phosphamide use leads to growth of primary tumor and metastases inhibition. Tumor growth inhibition was 34% on 21st day after cyclophosphamide inject. The number of metastases decreased by 4.7times (p<0,01). Metastatic area reduced. Metastasis frequency made 100%. In addition, the course of cyclophosphamide application caused inhibition of granulocytic and lymphoid hematopoiesis. The reducing the number of segmented neutrophils and lymphocytes was showed on the 3rd day after 1, 2 and 3 injections of cyclophosphamide. The model can be used to study the efficacy of drugs in tumor therapy and in correction of such toxic manifestation of chemotherapy as leukopenia.

Predictors of Irinotecan Toxicity and Efficacy in Treatment of Metastatic Colorectal Cancer

The colorectal cancer ranks high among the malignant tumours in incidence and mortality and irinotecan is standardly used in palliative treatment of metastatic disease in every therapeutic line. Unfortunately, the treatment with irinotecan is often associated with severe toxicities, especially neutropenia and diarrhea. The majority of the toxic manifestation is caused by the insufficient deactivation (glucuronidation) of irinotecan active metabolite SN-38 by UGT1A enzyme. The elevated SN-38 plasma concentration is responsible for the hematological and gastrointestinal toxicity that can become life-threatening. The patients carrying the mutation of the gene encoding UGT1A enzyme lack the ability of bilirubin glucuronidation, and suffer from the inherited un-conjugated hyperbilirubinemia (Gilbert syndrome, Crigler- Najjar type 1 and 2 syndrome). The mutations in other enzyme systems also play role in the etiopathogenesis of the irinotecan toxicity: CYP3A (cytochrome P-450), ABC family of transmembrane transporters (adenosine-triphosphate binding cassette). The goal of the contemporary research is to determine the predictive factors that will enable the individual adjustment of the individual drug dosage while minimising the adverse effects and maintaining the treatment benefit.

A Search to Predict Potential for Drug-Induced Cardiovascular Toxicity

This is a brief review of properties of cardiovascular function that should be considered for interrogation in studies of toxicology and/or safety pharmacology for non-cardiologists and non-physiologists. Since concern over the rarely occurring, unusual, and drug-induced tachycardia, Torsade de pointes, is a leading cause for cessation of development of potential drugs and for removal of drugs from the market, therefore, the toxic manifestation of drugs will be emphasized. The putative origin of torsade de pointes, and the origin of the electrocardiogram and electrocardiographic features of ventricular arrhythmias will be discussed.

Systemic Toxicity of Levobupivacaine, Bupivacaine, and Ropivacaine during Continuous Intravenous Infusion to Nonpregnant and Pregnant Ewes

Background Levobupivacaine, the single levorotatory isomer of bupivacaine, is now available for clinical use. This study was undertaken to determine whether pregnancy affects the systemic toxicity of levobupivacaine and to compare the systemic toxicity of levobupivacaine with that of bupivacaine and ropivacaine. Methods Chronically prepared nonpregnant and pregnant sheep were randomized to receive an intravenous infusion of 0.52% levobupivacaine, 0.52% bupivacaine, or 0.50% ropivacaine at a constant rate of 0.1 ml x kg(-1) x min(-1) until circulatory collapse. The investigators were blinded to the identity of the local anesthetic. Physiologic parameters, including cardiac rhythm, were monitored throughout the study. Arterial blood samples were obtained before infusion and at the onset of toxic manifestations. These were analyzed for total and free serum drug concentrations as well as arterial blood pH and gas tensions. Results The doses of all three drugs required to produce convulsions were lower in pregnant than nonpregnant animals. However, as the infusion continued, there were no significant differences between pregnant and nonpregnant ewes in the dose of drug required to produce more advanced manifestations of toxicity: hypotension, apnea, and circulatory collapse. The mean cumulative dose and serum concentration at each toxic manifestation was lowest for bupivacaine, intermediate for levobupivacaine, and highest for ropivacaine in both pregnant and nonpregnant animals. For all three local anesthetics, there were no significant differences between pregnant and nonpregnant ewes in total and free serum drug concentrations, except that at circulatory collapse, these were higher in pregnant animals. Conclusions Pregnancy increases the risk of convulsions but not of more advanced manifestations of local anesthetic toxicity. The risk of toxicity is greatest with bupivacaine and least with ropivacaine. However, in actual clinical practice, the risk of systemic toxicity may also be affected by the relative potency and effectiveness of these drugs.

Clinical and Pathologic Aspects of Cardiomyopathy From Ipecac Administration in Munchausen's Syndrome by Proxy

Syrup of ipecac is an important component of the emergency management of acute toxic ingestion in children. It is generally safe for acute emergency use, and is recommended for first aid kits in homes with children. However, there are important toxic effects of excessive or long-term ingestion of syrup of ipecac. Cardiomyopathy is a potentially fatal, but often reversible, toxic manifestation of ipecac abuse, most commonly occurring in patients with bulimia. Another setting in which ipecac abuse occurs is Munchausen's syndrome by proxy. We report two cases, one fatal, of cardiomyopathy from ipecac toxicity secondary to Munchausen's syndrome by proxy.

Mobilization and Distribution of Beryllium Over the Course of Chelation Therapy with Some Polyaminocarboxylic Acids in the Rat

The efficacy of three common polyaminocarboxylic acids in the treatment of experimental beryllium intoxication was investigated in male rats. N-(2-hydroxyethyl) ethylene diamine triacetic acid (HEDTA) was more effective than calcium disodium ethylenediamine tetraacetic acid (CaNa2EDTA) in reducing the beryllium concentration of the blood, kidneys and spleen and reducing beryllium-induced inhibition of hepatic alkaline phosphatase activity. HEDTA was also most effective in reducing histopathological lesions in the liver and spleen. Compared to these two chelators, the third amino chelator, calcium trisodium diethylene triaminepenta acetic acid (CaNa3DTPA) produced severe deleterious effects in the liver and systemic toxicity. The results suggest that HEDTA is a promising chelator for beryllium toxicity while DTPA enhances the toxic manifestation of beryllium.