José Manuel Silva

Selection of the derivatization reagent--the case of human blood cholesterol, its precursors and phytosterols GC-MS analyses.

Phytosterols (PS; β-sitosterol and campesterol) and cholesterol precursors (CP; desmosterol and lathosterol) have been suggested as important biochemical markers of cholesterol intestinal absorption and liver biosynthesis, respectively. Given that these compounds appear in human blood in low amounts, sensitive and accurate methodology is required, such as gas chromatography-mass spectrometry (GC-MS) the most frequently used. One of the most critical factors of the GC analytical determination is the step of derivatization. Thus, the main objective of the present study was compare and select the better (one out of three) silylation mixtures as follows: N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide/ammonium iodide (MTBSTFA:NH(4)I), N-O-bis-(trimethylsilyl) trifluoroacetamide/trimethylchlorosilane (BSTFA:TMCS), and N-methyl-N-(trimethylsilyl)-trifluoroacetamide/1,4-dithioerythritol/trimethyliodosilane (MSTFA:DTE:TMIS). The results of this study are discussed and accompanied by a brief review on the importance and principles of derivatization process, specifically in silylation reactions in GC-MS sterols analyses. Furthermore, a scrutiny of some published results is presented, along with additional information about mass spectral data of these potentially useful compounds. Interestingly, the results of the study showed that from the three validated methodologies, the selected one, based on the best relation specificity/sensibility, is MSTFA:DTE:TMIS. With this silylation procedure for simultaneous determination of PS and CP in human serum by GC-MS in selected ion monitoring (SIM) mode, good linearity (r(2)≥0.931), precision (repeatability ranging from 0.92 to 3.91 CV and intermediate precision ranging from 5.12 to 6.33) and recoveries (≥93.6%) were obtained. Thus, it proved to be a helpful methodology in the quantification of predominant serum cholesterol origin in each patient.

Satisfação com o Internato Médico em Portugal

INTRODUCTION In the last years, the global context of medical education and Medical Residency programs in Portugal suffered substantial changes. The primary objective of this study was to evaluate and characterize medical residents ́ satisfaction with medical residency programs in Portugal and to identify features that could be improved. MATERIAL AND METHODS We utilized as model the survey Postgraduate Hospital Educational Environment Measure that has been developed in the United Kingdom and is speci cally targeted to medical residents. The survey was translated and adapted to the Portuguese reality. The survey was available online during April and May of 2016. RESULTS A total of 3456 responses were obtained, corresponding to a response rate of 35%. Endocrinology/Nutrition, Cardiology, Anesthesiology, Family Physician and Gastroenterology were the specialties in which the degree of satisfaction was higher, while Forensic Medicine, Medical Oncology, Internal Medicine, General Surgery and Pneumology showed the lowest level of satisfaction. DISCUSSION This study presented a high response rate when compared to previous studies. Portuguese medical residents presented high levels of satisfaction. Depending on year of medical residency, region, type of specialty and type of hospital marked asymmetries were noticed. CONCLUSION The survey ́s results should constitute in the future a support tool for the implementation of local and national measures relating to the medical residency. It is advisable to regularly conduct satisfaction surveys to medical residents.