Introduction and evaluation of case-based learning in the first foundational course of an undergraduate medical curriculum

Case-based learning (CBL) has been proposed as an effective method to promote student knowledge and motivation. The timing and methods for implementation have varied among schools, and data regarding the effectiveness of this pedagogy compared to other learning modalities are inconclusive. We introduced five different cases in the first course of our medical school as part of small-group CBL, and monitored student satisfaction and performance in summative evaluations. We observed that (1) students were very satisfied with the CBL sessions; (2) performance in essay examinations was significantly higher in CBL topics, compared to non-CBL topics, as evaluated at the end of the course, and three months after course conclusion; and (3) there was a trend of higher performance in multiple-choice questions about CBL topics, but this was not statistically significant. Our results indicate that CBL is an acceptable pedagogy to be incorporated from the beginning of undergraduate medical education to promote acquisition and retention of knowledge, students’ interest in foundational sciences, and integration of basic science disciplines and clinical medicine. When evaluating knowledge acquired using the CBL method, integrative essays represent a valuable tool to assess the depth of comprehension and application of information.     

Molecular Epidemiology of Trypanosomatids and <Emphasis Type="Italic">Trypanosoma cruzi</Emphasis> in Primates from Peru

We determined the prevalence rate and risk of infection of Trypanosoma cruzi and other trypanosomatids in Peruvian non-human primates (NHPs) in the wild (n = 126) and in different captive conditions (n = 183). Blood samples were collected on filter paper, FTA cards, or EDTA tubes and tested using a nested PCR protocol targeting the 24Sα rRNA gene. Main risk factors associated with trypanosomatid and T. cruzi infection were genus and the human–animal context (wild vs captive animals). Wild NHPs had higher prevalence of both trypanosomatids (64.3 vs 27.9%, P < 0.001) and T. cruzi (8.7 vs 3.3%, P = 0.057), compared to captive NHPs, suggesting that parasite transmission in NHPs occurs more actively in the sylvatic cycle. In terms of primate family, Pitheciidae had the highest trypanosomatid prevalence (20/22, 90.9%) and Cebidae had the highest T. cruzi prevalence (15/117, 12.8%). T. cruzi and trypanosomatids are common in Peruvian NHPs and could pose a health risk to human and animals that has not been properly studied.     

Effects of chlorpyrifos on enzymatic systems of Cydia pomonella (Lepidoptera: Tortricidae) adults

The control program of codling moth (Cydia pomonella L.) in the Río Negro and Neuquén Valley is intended to neonate larvae. However, adults may be subjected to sublethal pesticide concentrations generating stress which might enhance both mutation rates and activity of the detoxification system. This study assessed the exposure effects of chlorpyrifos on target enzyme and, both detoxifying and antioxidant systems of surviving adults from both a laboratory susceptible strain (LSS) and a field population (FP). The results showed that the FP was as susceptible to chlorpyrifos as the LSS and, both exhibited a similar chlorpyrifos‐inhibitory concentration 50 (IC₅₀) of acetylcholinesterase (AChE). The FP displayed higher carboxylesterase (CarE) and 7‐ethoxycoumarine O‐deethylase (ECOD) activities than LSS. Both LSS and FP showed an increase on CarE activity after the exposure to low‐chlorpyrifos concentrations, followed by enzyme inhibition at higher concentrations. There were no significant differences neither in the activities of glutathione S‐transferases (GST), catalase (CAT) and superoxide dismutase (SOD) nor in the reduced glutathione (GSH) content between LSS and FP. Moreover, these enzymes were unaffected by chlorpyrifos. In conclusion, control adults from the FP exhibited higher CarE and ECOD activities than control adults from the LSS. AChE and CarE activities were the most affected by chlorpyrifos. Control strategies used for C. pomonella, such as rotations of insecticides with different modes of action, will probably delay the evolution of insecticide resistance in FPs from the study area.     

Amylosucrase‐mediated β‐carotene encapsulation in amylose microparticles

The β‐carotene embedded amylose microparticles (BC‐AmMPs) were prepared in one‐step by utilizing the unique catalytic activity of amylosucrase from Deinococcus geothermalis (DgAS), which synthesizes linear amylose chains using sucrose as the sole substrate. Synthesized amylose chains self‐assembled with β‐carotene to form well‐defined spherical microparticles with an encapsulation yield of 65%. The BC‐AmMPs produced (average diameter ～8 µm) were bright orange due to the embedded β‐carotene, and this was confirmed by Raman analysis. XRD showed BC‐AmMPs had a B‐type amylose crystal structure with a degree of crystallinity lower than that of AmMPs. This lower crystallinity of AmMP after BC encapsulation was confirmed by DSC analysis. Decreased enthalpy of gelatinization (ΔH_gel) of BC‐AmMP implied that molecular order within the amylose microstructure was influenced by the presence of BC. The stability of BC against environmental stresses, such as UV light and oxidative stress, was significantly enhanced by its encapsulation. The authors propose a new approach to the preparation of an amylose based carrier system for active compounds or expensive food ingredients with poor stabilities during storage or processing. Given that amylose is a safe food material, the devised encapsulation system will find wide range of practical applications in the food industry. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1640–1646, 2017     

Arbuscular mycorrhizal fungi in the growth and extraction of trace elements by Chrysopogon zizanioides (vetiver) in a substrate containing coal mine wastes

Vetiver (Chrysopogon zizanioides) is a fast-growing, high biomass producing plant employed for environmental rehabilitation. The study evaluated the effects of arbuscular mycorrhizal fungi (AMF) on the growth and trace element phytoextracting capabilities of vetiver in a substrate containing coalmine wastes in Southern Brazil. AMF included Acaulospora colombiana, Acaulospora morrowiae, Acaulospora scrobiculata, Dentiscutata heterogama, Gigaspora margarita, and Rhizophagus clarus. Among those, A. colombiana, G. margarita, and R. clarus promoted higher growth. AMF stimulated average increments in the accumulated P of 82% (roots), 194% (shoots first harvest—90 days) and 300% (shoots second harvest—165 days) and affected the phytoextraction of trace elements by vetiver, with larger concentrations in the roots. Plants inoculated with A. colombiana, A. morrowiae, and A. scrobiculata, in addition to the control, presented the highest levels of Cu and Zn in the roots. Overall, G. margarita stimulated the highest production of biomass, and, therefore, showed the most significant levels of trace elements in the plants. This work shows the benefits of certain AMF (especially A. morrowiae, G. margarita, and R. clarus) for the production of biomass and P uptake by vetiver, demonstrating the potential of those species for the rehabilitation of coal-mine-degraded soils.     

Overview and Future Potential of Buccal Mucoadhesive Films as Drug Delivery Systems for Biologics

The main route of administration for drug products is the oral route, yet biologics are initially developed as injectables due to their limited stability through the gastrointestinal tract and solubility issues. In order to avoid injections, a myriad of investigations on alternative administration routes that can bypass enzymatic degradation and the first-pass effect are found in the literature. As an alternative site for biologics absorption, the buccal route presents with a number of advantages. The buccal mucosa is a barrier, providing protection to underlying tissue, but is more permeable than other alternative routes such as the skin. Buccal films are polymeric matrices designed to be mucoadhesive properties and usually formulated with permeability enhancers to improve bioavailability. Conventionally, buccal films for biologics are manufactured by solvent casting, yet recent developments have shown the potential of hot melt extrusion, and most recently ink jet printing as promising strategies. This review aims at depicting the field of biologics-loaded mucoadhesive films as buccal drug delivery systems. In light of the literature available, the buccal epithelium is a promising route for biologics administration, which is reflected in clinical trials currently in progress, looking forward to register and commercialize the first biologic product formulated as a buccal film.