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Introduction and aims: Cirrhosis is the common outcome of liver diseases. It can be decompensated and lead to the development of complications, such as encephalopathy. Hyperammonemia that develops due to liver dysfunction is etiopathologically related to hepatic encephalopathy. Caffeine increases the activity of the urea cycle in the liver, augmenting ammonia degradation. By antagonizing adenosine receptors, it also has a hepatoprotective effect, impeding the formation of fibrosis, as well as having a stimulating effect on the central nervous system. The present study analyzed the effects of caffeine on the progression of cholestatic liver fibrosis and hepatic encephalopathy. Materials and methods: An experimental model of cholestatic liver fibrosis, through common bile duct ligature, and of hepatic encephalopathy, through the administration of a high-protein diet, was constructed. Male Wistar rats (n = 32) were equally divided into 4 groups. The experiment lasted 28 days, with the administration of 50 mg/kg/day of caffeine. Laboratory tests, histologic analyses of the liver and encephalon, open field tests (OFTs), and daily behavioral analyses were carried out. Results: The ligated animals treated with caffeine had lower mean transaminase levels and improved histologic aspects of the liver and encephalon. The untreated ligated animals were clearly lethargic and apathetic at the last week of the experiment, confirmed by reduced exploratory activity during the OFT. Conclusion: Caffeine improved the microarchitecture of the liver and encephalon of the cirrhotic animals and prevented the decrease in exploratory behavior of the animals during the OFT. Resumen: Introducción y objetivos: La cirrosis es el desenlace común de las enfermedades hepáticas. Puede ser descompensada y llevar al desarrollo de complicaciones como la encefalopatía. La hiperamonemia que se desarrolla debido a la disfunción hepática está etiopatológicamente relacionada con la encefalopatía hepática. La cafeína (CAF) aumenta la actividad del ciclo de la urea en el hígado, aumentando la degradación del amonio. Además, al antagonizar receptores de adenosina, ejerce un efecto hepatoprotector, impidiendo la formación de fibrosis y tiene un efecto estimulante en el sistema nervioso central. El objetivo del presente estudio fue el análisis de los efectos de la cafeína sobre la evolución de la fibrosis hepática colestásica y de la encefalopatía hepática. Material y métodos: Se construyó un modelo experimental de fibrosis hepática colestásica, por medio de la ligadura del conducto biliar común, y de encefalopatía hepática, con la administración de una dieta hiperprotéica. Treinta y dos ratas Wistar machos fueron divididas igualmente en 4 grupos. El experimento duró 28 días, con administración de CAF 50 mg/kg/día. Se realizaron pruebas de laboratorio, análisis histológicos de hígado y encéfalo, pruebas de campo abierto (PCA) y análisis conductuales diarios. Resultados: Los animales ligados tratados con CAF presentaron menores medias de transaminasas y mejorías histológicas en hígado y encéfalo. El grupo ligado sin tratamiento se presentó claramente letárgico y apático en la última semana de experimento, lo cual fue comprobado por la disminución de la actividad exploratoria durante la PCA. Conclusión: La CAF mejoró la microarquitectura hepática y encefálica de los animales cirróticos. Además, impidió la disminución de la actividad exploratoria de los animales durante la PCA.

Resumen: Introducción y objetivos: La cirrosis es el desenlace común de las enfermedades hepáticas. Puede ser descompensada y llevar al desarrollo de complicaciones como la encefalopatía. La hiperamonemia que se desarrolla debido a la disfunción hepática está etiopatológicamente relacionada con la encefalopatía hepática. La cafeína (CAF) aumenta la actividad del ciclo de la urea en el hígado, aumentando la degradación del amonio. Además, al antagonizar receptores de adenosina, ejerce un efecto hepatoprotector, impidiendo la formación de fibrosis y tiene un efecto estimulante en el sistema nervioso central. El objetivo del presente estudio fue el análisis de los efectos de la cafeína sobre la evolución de la fibrosis hepática colestásica y de la encefalopatía hepática. Material y métodos: Se construyó un modelo experimental de fibrosis hepática colestásica, por medio de la ligadura del conducto biliar común, y de encefalopatía hepática, con la administración de una dieta hiperproteica. Treinta y dos ratas Wistar machos fueron divididas igualmente en cuatro grupos. El experimento duró 28 días, con administración de CAF 50 mg/kg/d. Se realizaron pruebas de laboratorio, análisis histológicos de hígado y encéfalo, pruebas de campo abierto (PCA) y análisis conductuales diarios. Resultados: Los animales ligados tratados con CAF presentaron menores medias de transaminasas y mejorías histológicas en hígado y encéfalo. El grupo ligado sin tratamiento se presentó claramente letárgico y apático en la última semana de experimento, lo cual fue comprobado por la disminución de la actividad exploratoria durante la PCA. Conclusión: La CAF mejoró la microarquitectura hepática y encefálica de los animales cirróticos. Además, impidió la disminución de la actividad exploratoria de los animales durante la PCA. Abstract: Introduction and aims: Cirrhosis is the common outcome of liver diseases. It can be decompensated and lead to the development of complications, such as encephalopathy. Hyperammonemia that develops due to liver dysfunction is etiopathologically related to hepatic encephalopathy. Caffeine increases the activity of the urea cycle in the liver, augmenting ammonia degradation. By antagonizing adenosine receptors, it also has a hepatoprotective effect, impeding the formation of fibrosis, as well as having a stimulating effect on the central nervous system. The present study analyzed the effects of caffeine on the progression of cholestatic liver fibrosis and hepatic encephalopathy. Materials and methods: An experimental model of cholestatic liver fibrosis, through common bile duct ligature, and of hepatic encephalopathy, through the administration of a high-protein diet, was constructed. Male Wistar rats (n = 32) were equally divided into 4 groups. The experiment lasted 28 days, with the administration of 50 mg/kg/day of caffeine. Laboratory tests, histologic analyses of the liver and encephalon, open field tests (OFTs), and daily behavioral analyses were carried out. Results: The ligated animals treated with caffeine had lower mean transaminase levels and improved histologic aspects of the liver and encephalon. The untreated ligated animals were clearly lethargic and apathetic at the last week of the experiment, confirmed by reduced exploratory activity during the OFT. Conclusion: Caffeine improved the microarchitecture of the liver and encephalon of the cirrhotic animals and prevented the decrease in exploratory behavior of the animals during the OFT.

Identificaram-se e caracterizaram-se a resistência e a multirresistência aos principais antimicrobianos usados no tratamento de mastite bovina causada por Escherichia coli. A concentração inibitória mínima (MIC) e o sistema de efluxo foram detectados pelas curvas de crescimento, com base na densidade óptica, em diferentes concentrações da droga e na presença e na ausência do desacoplador da força próton-motora (PMF). E. coli 1 foi resistente à neomicina e à gentamicina; E. coli 3 e 4, à tetraciclina e à estreptomicina; e E. coli 2 e 6 à gentamicina. E. coli 5 apresentou modelo de sensibilidade. Observou-se que MICs de todos os antimicrobianos dos multirresistentes (E. coli 1, 3 e 4) diminuíram na presença do desacoplador, o que sugere sistema de efluxo multidrogas. Após cura, apenas E. coli 1 apresentou modelo de sensibilidade, porém não houve alterações das MICs, antes e após adição do desacoplador. Os resultados indicam possível presença de mecanismo de resistência dependente da PMF codificado, ou parte dele, em plasmídeo.Resistance and multiresistance to main antimicrobials used for treating bovine mastitis caused by Escherichia coli were identified and characterized. The minimal inhibitory concentration (MIC) and efflux systems were detected by the use of growth curves based on optical density at different drug concentrations and both presence and absence of uncoupler of the proton-motive force (PMF). E. coli 1 was resistant to neomycin and gentamycin, E. coli 3 and 4 were resistant to tetracycline and streptomycin, whereas E. coli 2 and 6 were resistant to gentamycin. E. coli 5 showed sensibility model. MICs of all antimicrobials of the multiresistant samples (E. coli 1, 3, and 4) were decreased in presence of the uncoupler, therefore suggesting the presence of the multidrug efflux system. After healing, only E. coli 1 showed sensibility model, however no alteration occurred in MIC(s) before and after adding the uncoupler. Those data inform the possible presence of a PMF dependent resistance mechanism that is totally or partly codified in plasmid.

One hundred and ninety-seven isolates of Gram-negative bacteria, comprising 10 genera, were isolated from poultry carcasses at a processing plant in order to investigate resistance to low levels of antibiotics. The samples were taken just after evisceration and before inspection. Most of the isolates were of Samonella and Escherichia. Other genera present were Enterobacter, Serratia, Klebsiella, Kluyvera, Erwinia, Citrobacter, Pseudomonas and Aeromonas. Distinct profiles of antibiotic resistance were detected. Resistance to more than two antibiotics predominated and spanned several classes of antibiotics. Salmonellae and escherichiae were mainly resistant to the aminoglycosides, followed by tetracycline, nitrofuran, sulpha, macrolide, chloramphenicol, quinolones and beta-lactams. Most isolates were sensitive to 30mug/ml olaquindox, the growth promoter in use at the time of sampling. However, many were resistant to a level of 10mug/ml and 13mug/ml olaquindox, levels present in the gut due to the dilution in the feed. The results suggest a possible role of low level administration of antibiotics to broilers in selecting multi-resistant bacteria in vivo.