RESUMEN
Biomaterials that effectively act in biological systems, as in treatment and healing of damaged or lost tissues, must be able to mimic the properties of the body's natural tissues in its various aspects (chemical, physical, mechanical and surface). These characteristics influence cell adhesion and proliferation and are crucial for the success of the treatment for which a biomaterial will be required. In this context, the electrospinning process has gained prominence in obtaining fibers of micro- and nanometric sizes from polymeric solutions aiming to produce scaffolds for tissue engineering. In this manuscript, poly(vinylidene fluoride) (PVDF) was used as a polymeric matrix for the manufacture of piezoelectric scaffolds, exploring the formation of the ß-PVDF piezoelectric phase. Micro- and nanometric hydroxyapatite (HA) particles were incorporated as a dispersed phase in this matrix, aiming to produce multifunctional composite membranes also with bioactive properties. The results show that it is possible to produce membranes containing micro- and nanofibers of the composite by the electrospinning process. The HA particles show good dispersion in the polymer matrix and predominance of ß-PVDF phase. Also, the composite showed apatite growth on its surface after 21 days of immersion in simulated body fluid (SBF). Tests performed on human fibroblasts culture revealed that the electrospun membranes have low cytotoxicity attesting that the composite shows great potential to be used in biomedical applications as bone substitutions and wound healing.
RESUMEN
BACKGROUND: Truck drivers work under conditions that predispose them to a high prevalence of risk factors for the development of cardiovascular disease (CVD); however, these factors have not been fully evaluated and are not usually considered to be within the scope of health or labor services. METHODS: An observational cross-sectional study was conducted on 250 long-distance truck drivers; the drivers were all male and were aged 18-60 years. The clinical evaluation consisted of an assessment of social habits and demographic data and an evaluation of risk factors for CVD at 3 time points separated by a one-week interval. To assess the associations with risk factors were used univariate and multivariate analysis. The suitability of the final model fit was assessed via the Hosmer-Lemeshow test. The significance level was set at 5%. RESULTS: Among all of the subjects, the prevalence of physical inactivity was 72.8%; consumption of alcoholic beverages, 66.8%; routine use of some type of stimulant during work activities, 19.2%; and smoking, 29%. Only 20.8% had a healthy weight, and 58.2% had an abdominal circumference greater than 102 cm. A diagnosis of arterial hypertension was confirmed in 45.2%, and abnormal glucose levels were detected in 16.4%. Although some of the truck drivers were aware of these conditions, most were not taking specific medications. The logistic regression analysis shows that the odds of hypertension and abnormal glucose levels were increased in truck drivers with abdominal obesity. Age and the family history of premature CVD also increased the chances of hypertension and the abnormal blood glucose levels were related to II or III grade obesity. CONCLUSION: Long-distance truck drivers showed a high prevalence of a cluster of cardiovascular risk factors; these risk factors make the drivers highly susceptible to the development of CVD. The associated risk factors, low compliance with drug treatment, and unique features of this profession suggest that traditional precautions are not sufficient to change this scenario.
