Evaluation of prophylactic and therapeutic effects of silymarin on acute toxicity due to tetracycline severe overdose in cats: a preliminary study

The aim of the present study was to determine the protective action of silymarin on acute toxicity due to tetracycline severe overdose in cats. Thirty healthy cats were randomly allotted into five equal groups. Cats in group A were given tetracycline [single dose 120 mg/kg, p.o.]; group B consisted of cats that received silymarin [single dose 30 mg/kg, p.o.] concurrent with tetracycline administration; groups C, D and E were treated as group B, but silymarin was administered 4, 12 and 24 h after tetracycline administration, respectively. The serum concentrations of alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase [ALP], lactate dehydrogenase [LDH], BUN, serum creatinine and total and direct bilirubin were measured before tetracycline administration and 4, 12, 24 and 72 h later. A single oral administration of tetracycline increased, significantly, serum concentrations of ALT, AST, ALP, LDH in all cats of group A, after 24 h [P<0.001]. In groups B and C, levels of serum enzyme activities remained within normal values. In group D, there were changes in levels of serum enzyme activities, but the difference was not significant [P>0.05]. In group E, levels of serum enzyme activities were significantly higher than normal values [P<0.05]. The difference was significant between groups A and E with groups B and C for the serum enzymes [P<0.05]. In conclusion, silymarin can protect liver tissue against hepatotoxicity in cats with tetracycline severe overdose, particularly in the first 4 h after exposure

Frecuencia de la contaminación de la leche disponible en el Valle de México con estreptomicina, tetraciclina y penicilina / Frecuency of contamination of milk with streptomicine tetracicline and peniciline in Mexico City

Este trabajo se efectuó con el objeto de establecer la magnitud de la contaminación con resíduos de antibióticos de las leches comerciales disponibles en el Valle de México. Se obtuvieron 125 muestras de leche de diferentes marcas comerciales durante el período marzo-julio de 1985 y fueron analizadas para penicilina, estreptomicina y tetraciclina, siguiendo los métodos microbiológicos de cilindro en placa. Solamente el 9.6% de las muestras resultaron libres de antibióticos, el 25% contenían penicilina, el 60% estreptomicina, el 70% tetraciclina y más del 80% contenían 2 o los 3 antibióticos. Los niveles promedios encontrados para penicilina, estreptomicina y tetraciclina fueron 0.11 UI/ml, 0.02 microng/ml y 0.07 microng/ml, respectivamente. Ninguna marca de leche resultó negativa en todas las muestras y las 8 muestras de leche para bebé también resultados positivas a uno o a dos de los antibióticos estudiados. Aunque los niveles encontrados de penicilina, estroptomicina y tetraciclina son muy bajos, su ingestión diaria a través de la leche puede tener repercusiones en la salud pública, especialmente en los niños