Use of MALDI-TOF MS technology to evaluate adulteration of small ruminant milk with raw bovine milk.

Detection of adulteration of small ruminant milk is very important for health and commercial reasons. New analytical and cost-effective methods need to be developed to detect new adulteration practices. In this work, we aimed to explore the ability of the MALDI-TOF mass spectrometry to detect bovine milk in caprine and ovine milk using samples from 18 dairy farms. Different levels of adulteration (0.5, 1, 5, 10, 20, 40, 60, and 80%) were analyzed during the lactation period of goat and sheep (in May, from 60 to 90 d in milk, and in August, from 150 to 180 d in milk). Two different ranges of peptide-protein spectra (500-4,000 Da; 4-20 kDa) were used to establish a calibration model for predicting the concentration of adulterant using partial least squares and generalized linear model with lasso regularization. The low molecular weight part of the spectra together with the generalized linear model with lasso regularization regression model appeared to have greater potential for our aim of detection of adulteration of small ruminants' milk. The subsequent prediction model was able to predict the concentration of bovine milk in caprine milk with a root mean square error of 11.4 and 17.0% in ovine milk. The results offer compelling evidence that MALDI-TOF can detect the adulteration of small ruminants' milk. However, the method is severely limited by (1) the complexity of the milk proteome resulting from the adulteration technique, (2) the potential degradation of thermolabile proteins, and (3) the genetic variability of tested samples. Additionally, the root mean square error of prediction based only on one individual sample adulteration series can drop down to 6.34% for quantification of adulterated caprine milk and 6.28% for adulterated ovine milk for the full set of concentrations or down to 2.33 and 4.00%, respectively, if we restrict only to low concentrations of adulteration (0, 0.5, 1, 5, 10%).

Detection of bovine milk adulteration in caprine milk with N-acetyl carbohydrate biomarkers by using 1H nuclear magnetic resonance spectroscopy.

In a return to tradition, the popularity of caprine milk is on the rise. However, particularly in countries with developed dairy industries based on bovine milk, there is the risk of adulteration with bovine milk, which is a cheaper alternative. Thus, a rapid, robust, and simple method for the detection of bovine milk added to caprine milk is necessary, and 1H nuclear magnetic resonance spectroscopy appears to provide a solution. A matrix of 115 pure and artificially adulterated pasteurized milk samples was prepared and used to discover biomarkers of bovine milk that are independent of chemical and biological variation caused by factors such as genetics, diet, or seasonality. Principal component analysis and orthogonal projections to latent structures discriminant analysis of pure bovine milk and pure caprine milk revealed spectral features that were assigned to the resonances of 4 molecules. Of these, the peaks corresponding to protons in the N-acetylglucosamine and N-acetylgalactosamine acetyl moieties showed significant applicability for our method. Receiver operating characteristic curve analysis was used to evaluate the performance of the peak integrals as biomarkers of adulteration. This approach was able to distinguish caprine milk adulterated with 5% of bovine milk with 84.78% accuracy and with 10% of bovine milk an excellent 95.65% accuracy. This study demonstrates that N-acetyl carbohydrates could be used as biomarkers for the detection of bovine milk in caprine milk and could help in protecting caprine milk authenticity.

[Chemosensitivity prediction in tumor cells ex vivo--difficulties and limitations of the method]. / Predikce citlivosti nádorových bunek k chemoterapeutikum ex vivo--úskali a limitace vlastní metody.

Certain hope is entertained in the prediction of chemosensitivity in vitro/ ex vivo for the purpose of selecting the most effective treatment of malignant diseases with minimal patient loading. The possible choice of an effective substance based on the results of a simple ex vivo test would increase the success of the treatment in case of standard chemotherapy failure or in the treatment of primary chemoresistant tumor. MTT test seems to be an easy process for the prediction of chemosensitivity of isolated malignant cells ex vivo, however each method represents a simple tool, which can provide false results if incorrectly preformed. Numerous limitations significantly reduce the successful evaluation and constituent aspects of the methodic press to further reflections about the proper application of the test.

Atorvastatin-induced endothelial nitric oxide synthase expression in endothelial cells is mediated by endoglin.

Endoglin, a transforming growth factor ß (TGF-ß) receptor type III, is co-expressed with endothelial nitric oxide synthase (eNOS) in aortic endothelium in atherosclerotic plaques of mice. Interestingly, atorvastatin (ATV) is able to increase both endoglin and eNOS expression and reduce plaque size beyond its lipid lowering effects but by unknown mechanisms. We hypothesized whether inflammation modulates ATV-dependent induction of endoglin and eNOS expression in vitro in endothelial cells and whether ATV-induced eNOS expression is regulated via endoglin. After treatment of human umbilical vein endothelial cells (HUVECs) with TNF-α, endoglin and eNOS protein expression was reduced, concomitantly with increased levels of cell surface VCAM-1 and soluble endoglin, as determined by flow cytometry, Western blot and ELISA analyses. By contrast, ATV treatment increased endoglin and eNOS protein expression, while preventing TNF-α-mediated downregulation of endoglin and eNOS protein levels. Moreover, suppression of endoglin using small interfering RNA (siRNA), but not inhibition of TGF-ß signaling with SB431542, abrogated ATV-induced eNOS expression. These results suggest that ATV treatment prevents inflammation-reduced endoglin and eNOS expression in endothelial cells and that ATV-induced eNOS expression strongly depends on the proper expression of endoglin in HUVECs. Possible implications of these findings might be reflected in pathological conditions characterized by reduced expression of endoglin and eNOS as for example in hereditary hemorrhagic telangiectasia or in other endothelial dysfunctions.