Between 1996 and 1998, 580 litres of milk in Mexico were surveyed for aflatoxin B(1) (AFB(1)) and its metabolite aflatoxicol (AFL), which are mutagenic and carcinogenic mycotoxins that interconvert AFB(1)-AFL-AFB(1). The seven most consumed brands from different regions of Mexico included pasteurized and ultrapasteurized milk with four different fat levels: whole fat (28-33 g l(-1)), half-skimmed (10-20 g l(-1)), light (1-4 g l(-1)) and with vegetable oil (33 g l(-1)). Aflatoxins in each sample were concentrated with total aflatoxin immunoaffinity columns and quantitated by high-performance liquid chromatography. A milk sample was considered contaminated if it contained >/=0.05 microg l(-1) AFL. Pasteurization and ultrapasteurization of milk did not control contamination with AFL, which was present in 13% of samples at >/=0.05 microg l(-1) and in 8% at >/=0.5 microg l(-1), with a range of AFL from 0 to 12.4 microg l(-1). AFB(1) was present mainly in traces (0-0.4 microg l(-1)). The safest milk in relation to AFL contamination was imported milk powder with vegetable oil. There was a significant correlation between contamination of milk with AFL and the autumn (p<0.0002); the fat content was not significant.

High per capita milk consumption in Mexico indicated a strong need for documentation of aflatoxin M1 (AFM1) levels in milk. A survey of 580, 2-liter samples (n = 290), was conducted to quantify AFM1 using high-performance liquid chromatography, considering two maximum tolerance levels (0.05 and 0.5 microg/liter). We relate aflatoxin levels in the seven most consumed brands from different regions, with two processes (pasteurized and ultrapasteurized), different expiration dates, and different fat content: whole fat (28, 30, and 33 g), half-skimmed (10, 16, and 20 g), light (1, 2, and 4 g), and with vegetable oil. Pasteurization and ultrapasteurization did not diminish AFM1 contamination present at levels of 0 to 8.35 microg/liter in 40% of the milk samples at concentrations > or = 0.05 microg/liter and in 10% of the samples at > or = 0.5 microg/liter. Statistically significant relationships were AFM1 contamination with brand (P = 0.002 at the > or = 0.05 microg/liter level and P = 0.034 at the > or = 0.5 microg/ liter level) and higher AFM1 levels with mild or warm seasons of the year (P = 0.0003). Samples with greater fat content had slightly more probability (P = 0.067) of being contaminated by AFM1 at the > or = 0.5 microg/liter level. The milk with the lowest contamination of AFM1 was a brand imported as powder and rehydrated in Mexico.

No abstract

HPLC and Inhibitory Indirect ELISA (I.I. ELISA) methods for quantitation of aflatoxins (AF) in human urine were compared in terms of specificity, sensitivity, easiness and cost. I.I. ELISA was optimized in kind of antibody in use, type of plastic plate, adduct synthesis technique, peroxidase and antibody dilutions, etc. Both polyclonal (Cuban) and monoclonal (British) anti‐AF antibodies were statistically studied and the process was standardized. HPLC and electrophoresis were performed while synthetizing AFB1‐DNA and AFB1‐Cl‐Ovalbumin (AFB1‐Cl‐Ov) adducts. Costar polystyrene plate had the best adherence. Optimum coating dilution was 10 ng of AFB1‐Cl‐Ov per well. Dilutions of 1:1000 of monoclonal antibody from purified culture or 1:300 from monoclonal antibody from tissue culture and 1:1000 of peroxidase anti‐mouse conjugate were the best. Optimum separation with HPLC was obtained isocratically with 60% MeOH and 40% distilled water mobile phase. ELISA had a sensitivity of 1 pg mL−1 AFB1 and HPLC sensitivity was 0.1 ng mL−1 AFB1 with fluorescence detector and 4.5 ng mL−1 with UV detector. Monoclonal antibody gave more accurate results for determination of free and adducted AFB1 in urine analysis. Copyright © 1999 John Wiley & Sons, Ltd.

El término síndrome metabólico se refiere a una serie de factores de riesgo que resultan de un desbalance metabólico. Se han señalado varias causas para su desarrollo, entre las que destacan la ingesta excesiva de calorías y el sedentarismo. Este desbalance entre la ingesta y el gasto energético resulta en un incremento de peso en la forma de tejido adiposo, estrechamente asociado con múltiples desórdenes metabólicos. El síndrome metabólico, así como sus consecuencias, representan un serio problema de salud pública a nivel mundial. De ahí, surge la importancia del establecimiento de estrategias exitosas para su diagnóstico y tratamiento. Si bien los estudios epidemiológicos arrojan bastante información, por razones éticas y metodológicas, es necesario abordar los aspectos experimentales con modelos animales. A la fecha, existen múltiples modelos de manera que la elección de uno en específico requiere de la cuidadosa consideración de las variables o fenómenos a estudiar. En esta revisión se abordan aspectos generales del síndrome metabólico. Asimismo, se discuten las características generales de los modelos murinos más empleados en su estudio, como son los basados en dietas altas en carbohidratos y en grasas, además de los genéticos. En particular, para los modelos de dietas altas en grasa, se consideran otros aspectos como el porcentaje de kcal provenientes de la grasa, el tipo de ácidos grasos empleados, los regímenes de alimentación, así como los efectos multigeneracionales.