Microenvironment and tumor cells: two targets for new molecular therapies of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC), is one of the most frequent human cancer and is characterized by a high mortality rate. The aggressiveness appears strictly related to the liver pathological background on which cancer develops. Inflammation and the consequent fibro/cirrhosis, derived from chronic injuries of several origins (viral, toxic and metabolic) and observable in almost all oncological patients, represents the most powerful risk factor for HCC and, at the same time, an important obstacle to the efficacy of systemic therapy. Multiple microenvironmental cues, indeed, play a pivotal role in the pathogenesis, evolution and recurrence of HCC as well as in the resistance to standard therapies observed in most of patients. The identification of altered pathways in cancer cells and of microenvironmental changes, strictly connected in pathogenic feedback loop, may permit to plan new therapeutic approaches targeting tumor cells and their permissive microenvironment, simultaneousl

Relative dentifrice abrasivity on dentin and enamel

The abrasive characteristics of six (6) brands of toothpastes on Enamel and Dentin material were assessed. Human teeth were sliced to expose the dentin surface and then polished using 3 μm and 0.25 μm diamond paste. The outside surface of the tooth (after slicing) was used as is for the enamel surface testing. The surface smoothness was evaluated prior to testing using a surface profiler and averaging four (4) to five (5) readings across the surface for each sample. The tooth slices were then embedded into the acrylic plate surface by routing out an area with a dental drill and using polymethylmethacrylate (PMMA) to adhere the teeth to the plate. An acrylic abrasion machine was used to brush each sample for 3000 strokes with each of the toothpastes being tested. At least three (3) samples of each material were used for each paste. The same type of medium stiffness brush was used for each test. The surface smoothness was then re-assessed using the surface profiler again averaging four (4) to five (5) readings across the surface. The data was statistically analyzed and ranked by abrasiveness

TGFβ impairs HNF1α functional activity in Epithelial-to-Mesenchymal Transition interfering with the recruitment of CBP/p300 acetyltransferases

The cytokine transforming growth factor β (TGFβ) plays a crucial role in the induction of both epithelial-to-mesenchymal transition (EMT) program and fibro-cirrhotic process in the liver, where it contributes also to organ inflammation following several chronic injuries. All these pathological situations greatly increase the risk of hepatocellular carcinoma (HCC) and contribute to tumor progression. In particular, late-stage HCCs are characterized by constitutive activation of TGFβ pathway and by an EMT molecular signature leading to the acquisition of invasive and metastatic properties. In these pathological conditions, the cytokine has been shown to induce the transcriptional downregulation of HNF1α, a master regulator of the epithelial/hepatocyte differentiation and of the EMT reverse process, the mesenchymal-to-epithelial transition (MET). Therefore, the restoration of HNF1α expression/activity has been proposed as targeted therapeutic strategy for liver fibro-cirrhosis and late-stage HCCs. In this study, TGFβ is found to trigger an early functional inactivation of HNF1α during EMT process that anticipates the effects of the transcriptional downregulation of its own gene. Mechanistically, the cytokine, while not affecting the HNF1α DNA-binding capacity, impaired its ability to recruit CBP/p300 acetyltransferases on target gene promoters and, consequently, its transactivating function. The loss of HNF1α capacity to bind to CBP/p300 and HNF1α functional inactivation have been found to correlate with a change of its posttranslational modification profile. Collectively, the results obtained in this work unveil a new level of HNF1α functional inactivation by TGFβ and contribute to shed light on the early events triggering EMT in hepatocytes. Moreover, these data suggest that the use of HNF1α as anti-EMT tool in a TGFβ-containing microenvironment may require the design of new therapeutic strategies overcoming the TGFβ-induced HNF1α inactivation

Bioequivalence Study of Two Long-Acting Formulations of Oxytetracycline Following Intramuscular Administration in Bovines

The aim of this study was to evaluate the bioequivalence of two commercial long-acting formulations based on oxytetracycline (OTC) hydrochloride between the reference formulation (Terramycin LA, Pfizer) and a test formulation (Cyamicin LA, Fort Dodge Saude Animal). Both formulations were administered in a single intramuscular route at a dose of 20 mg OTC/kg of body weight in clinically healthy bovines. The study was carried out according to a one-period parallel design. Plasma samples were analyzed by high-pressure liquid chromatography. The limit of quantitation was 0.050 μg/mL with an accuracy of 101.67% with a coefficient of variation of 13.15%. Analysis of variance and 90% confidence interval tests were used to compare the bioavailability parameters (maximum plasma concentration, Cmax, and the area under the concentration-versus-time curve extrapolated to infinity, AUC0–∞) of both products. In the case of the time to maximum concentration (Tmax), non-parametric tests based on Wilcoxon’s signed rank test were preferred. The comparison of the mean AUC0–∞ values did not reveal any significant differences (311.40 ± 93.05 μg h/mL and 287.71 ± 45.31 μg h/mL, respectively). The results were similar for the Tmax (3.58 ± 0.90 h versus 3.42 ± 0.51 h). However, when comparing the mean Cmax some significant differences were found (8.73 ± 3.66 μg/mL and 10.43 ± 3.84 μg/mL, respectively). The 90% confidence intervals for the ratio of AUC0–∞ and Tmax values for the reference and test product are within the interval 80–125%, but the 90% confidence intervals for the ratio of Cmax falls outside the proposed interval. It was concluded that Cmax of test product are not within the 20% of those of the reference, thus suggesting that test OTC is not bioequivalent to the reference formulation.FarmaciaMedicin

YAP integrates the regulatory Snail/HNF4α circuitry controlling epithelial/hepatocyte differentiation

Yes-associated protein (YAP) is a transcriptional co-factor involved in many cell processes, including development, proliferation, stemness, differentiation, and tumorigenesis. It has been described as a sensor of mechanical and biochemical stimuli that enables cells to integrate environmental signals. Although in the liver the correlation between extracellular matrix elasticity (greatly increased in the most of chronic hepatic diseases), differentiation/functional state of parenchymal cells and subcellular localization/activation of YAP has been previously reported, its role as regulator of the hepatocyte differentiation remains to be clarified. The aim of this study was to evaluate the role of YAP in the regulation of epithelial/hepatocyte differentiation and to clarify how a transducer of general stimuli can integrate tissue-specific molecular mechanisms determining specific cell outcomes. By means of YAP silencing and overexpression we demonstrated that YAP has a functional role in the repression of epithelial/hepatocyte differentiation by inversely modulating the expression of Snail (master regulator of the epithelial-to-mesenchymal transition and liver stemness) and HNF4α (master regulator of hepatocyte differentiation) at transcriptional level, through the direct occupancy of their promoters. Furthermore, we found that Snail, in turn, is able to positively control YAP expression influencing protein level and subcellular localization and that HNF4α stably represses YAP transcription in differentiated hepatocytes both in cell culture and in adult liver. Overall, our data indicate YAP as a new member of the HNF4/Snail epistatic molecular circuitry previously demonstrated to control liver cell state. In this model, the dynamic balance between three main transcriptional regulators, that are able to control reciprocally their expression/activity, is responsible for the induction/maintenance of different liver cell differentiation states and its modulation could be the aim of therapeutic protocols for several chronic liver diseases

Posibles estrategias para la resistencia bacteriana en la salud pública

La problemática de la antibióticorresistencia genera preocupación en los más elevados niveles de decisión mundial, pues resulta un problema extremadamente severo para la salud pública. La OMS, OIE y FAO han emitido documentos conjuntos fijando posición y haciendo recomendaciones a los países miembros (Joint Workshops Ginebra 2003, Oslo 2004, Seúl 2006, Roma 2007), lo cual denota que es un problema multifactorial y que implica un riesgo creciente en salud humana, salud animal y medio ambiente. Los antibióticos son utilizados de diversas formas en medicina veterinaria. En primer lugar, el uso terapéutica, para el tratamiento de enfermedades infecciosas, del mismo modo que se realiza en medicina humana. El uso profiláctico, que implica la utilización de medicamentos para la prevención de enfermedades. El uso metafiláctico, que es exclusivo de medicina veterinaria e implica el tratamiento con antimicrobianos del lote de animales después de la aparición de una infección bacteriana en algunos individuos del grupo, con objeto de evitar un brote de la enfermedad. Y por último, el uso como promotores de crecimiento a dosis subterapéuticas. Las explotaciones intensivas, tal como es el caso de la producción avícola, porcina y bovina (feedlot) son sistemas cuyo objetivo central es lograr rápida ganancia de peso de los animales en cortos periodos de tiempo, a fin de satisfacer las demandas del mercado. Para ello, los individuos se confinan y crecen en grupos de grandes densidades con alimentación estimulada. Uno de los inconvenientes de este tipo de manejo, es la inmunodepresión animal con el consecuente riesgo de adquirir diferentes patologías y generar un contagio masivo con graves consecuencias económicas. Es por esto, que muchas veces se requiere de la implementación de antimicrobianos como herramientas profilácticas, metafilácticas, terapéuticas y promotoras del crecimiento. Sin embargo, es bien sabido que el uso indiscriminado e irracional de antibacterianos contribuye de manera importante a la selección, permanencia y transferencia de cepas bacterianas resistentes y multirresistentes en el entorno.Facultad de Ciencias Veterinaria