Improving the teaching skills of residents as tutors/facilitators and addressing the shortage of faculty facilitators for PBL modules

Background  

Residents play an important role in teaching of medical undergraduate students. Despite their importance in teaching undergraduates they are not involved in any formal training in teaching and leadership skills. We aimed to compare the teaching skills of residents with faculty in facilitating small group Problem Based Learning (PBL) sessions.     

Modification of rat brain Kv1.4 channel gating by association with accessory Kvβ1.1 and β2.1 subunits

 We have examined the effects of co-expression of Kvβ1.1 and Kvβ2.1 subunits on the gating of rat brain Kv1.4 channels, expressed in Xenopus oocytes. Expression of Kv1.4 subunits alone produced a rapidly inactivating ”A” type current, which activated at potentials beyond –60 mV in a solution containing high levels of rubidium. Current activation curves obtained from tail current measurements were fitted with a Boltzmann function, with V _1/2 = –47 mV and k = 10 mV. Neither the Kvβ1.1 nor Kvβ2.1 subunits altered the voltage dependence of activation. Both subunits accelerated the activation time constant of Kv1.4, without affecting its voltage dependence. Surprisingly, the Kvβ2.1 subunit, which lacks an N-terminal inactivation domain, was almost as effective as the Kvβ1.1 subunit in speeding up Kv1.4. Steady-state inactivation of Kv1.4 was unchanged upon co-expression with either Kvβ1.1 or Kvβ2.1 subunits. Kv1.4 recovered from inactivation with two time constants; apart from an ≈ 50% lengthening of the slow time constant with a high Kvβ2.1 injection ratio, neither time constant was altered by either the Kvβ1.1 or Kvβ2.1 subunits, suggesting little interaction with recovery from C-type inactivation. Clearly, β subunits have the potential to modify the gating of Kv1.4 channels in the brain more subtly than has been suggested previously. Received: 17 March 1997 / Accepted: 30 June 1997     

Late life metabolic syndrome, early growth, and common polymorphism in the growth hormone and placental lactogen gene cluster

Low rates of fetal and infant growth are associated with the metabolic syndrome and cardiovascular disease in later life. We investigated common genetic variation in the GH-CSH gene cluster on chromosome 17q23 encoding GH, placental lactogens [chorionic somatomammotropins (CSH)], and placental GH variant in relation to fetal and infant growth and phenotypic features of the metabolic syndrome in subjects aged 59-72 yr from Hertfordshire, UK. Allele groups T, D1, and D2 of a locus herein designated CSH1.01 were examined in relation to GH-CSH single nucleotide polymorphisms and to specific phenotypes. Average birth weights were similar for all genotype groups. Men with T alleles were significantly lighter at 1 yr of age, shorter as adults, and had higher blood pressures, fasting insulin (T/T 66% higher than D2/D2) and triglyceride concentrations, and insulin and glucose concentrations during a glucose tolerance test. Birth weight and 1-yr weight associations with metabolic syndrome traits were independent of the CSH1.01 effects. Common diversity in GH-CSH correlates with low 1-yr weight and with features of the metabolic syndrome in later life. GH-CSH genotype adds substantially to, but does not account for, the associations between low body weight, at birth and in infancy, and the metabolic syndrome.     

High sustained response to daily dosing of interferon with ribavirin in chronic hepatitis C patients naïve to therapy

Background : Viral kinetics suggests that daily administration of α‐interferon (IFN) will clear hepatitis C virus (HCV) RNA earlier and more frequently compared with standard t.i.w. To reduce the likelihood of viral replication, mutation and subsequent development of resistance, daily dosing with IFN may be appropriate. To determine the safety and efficacy of daily IFN with ribavirin in chronic HCV infection we performed a prospective study. Methods : Thirty‐five naïve adult HCV‐positive patients (25 male/10 female) were treated with IFN‐α2b; 5 MU daily for 2 weeks followed by 3 MU daily for 22 weeks and ribavirin 800–1200 mg/day depending on weight. Liver biopsy, performed in 25 patients, showed mild to moderate activity in 19 patients (76%) and severe activity in six patients (24%). Two patients showed staged IV fibrosis. Serotyping was performed in 29 patients by an enzyme immunoassay‐based Murex assay. Type 3 was the predominant serotype, present in 14 cases. Hepatitis C virus RNA was measured by the Chiron bDNA assay. Results : Mean baseline HCV‐RNA level was 14.2 ± 18.7 MEq/mL (median 6.09; range 0.2–92.5), which became undetectable in all but three patients at week 4. Normalization of alanine aminotransferase (ALT) at week 4 was seen in 27 patients. Three patients withdrew due to non‐compliance. Thirty‐two patients completed 24 weeks of therapy as per the protocol. At the end of treatment, the HCV‐RNA level was negative in 29 of 32 patients (90.6%) and ALT was normal in 31 of 32 patients (97%). Sustained viral response at 6 months follow up was seen in 28 of 32 patients (88%). The ALT level was normal in 28 of 32 patients (88%). Conclusion : Daily administration of IFN with ribavirin is well tolerated in the majority of patients. There is rapid elimination of virus with normalization of ALT and a significantly high sustained viral response. © 2002 Blackwell Publishing Asia Pty Ltd     

VE1 immunohistochemistry is an adjunct tool for detection of BRAF V600E mutation: Validation in thyroid cancer patients

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy among other endocrine tumors, and BRAF ^V600E is a frequent genetic mutation occurring in the disease. Although different molecular techniques, most importantly sequencing has been widely recognized as a gold standard but molecular diagnosis remains an expensive, laborious, and time‐intensive process. Recently, immunohistochemistry (IHC) with anti‐BRAF V600E (VE1) antibody has increased practical utility and implemented clinically for the detection of BRAF ^V600E mutation. Therefore, the study aimed to evaluate diagnostic accuracy of VE1 IHC for detecting the BRAF ^V600E mutation frequency and clinical implementation in diagnostic laboratories. In this study, 72 formalin fixed paraffin‐embedded tissues (FFPE) were used to determine the BRAF ^V600E mutation status using IHC and Sanger sequencing. The mutation was found in 29% and 28% cases using IHC and Sanger sequencing, respectively. Furthermore, the results showed 100% sensitivity, 98.07% specificity, 95.2% positive predictive value, and 100% negative predictive value. Notably, significant associations were found between BRAF ^V600E status and tumor stage, tumor focality, and extrathyroidal extensions, respectively. VE1 IHC was found to be a highly sensitive, specific, and diagnostically accurate method in this cohort. Therefore, BRAF ^V600E detection through IHC has been considered as the best tailored technique for routine pathology laboratories.     

Promising performance of chemically exfoliated Zr-doped MoS2 nanosheets for catalytic and antibacterial applications

Nanostructured materials incorporated with biological reducing agents have shown significant potential for use in bactericidal applications. Such materials have also demonstrated considerable efficacy to counter effects of chemical toxicity. In this study, nanostructured molybdenum disulfide (MoS₂) was doped with various concentrations (2.5, 5, 7.5, 10 wt%) of zirconium (Zr) using a hydrothermal route in order to assess its antimicrobial and catalytic potential. Doped and control samples were characterized with various techniques. X-ray diffraction (XRD) analysis confirmed the presence of the hexagonal phase of MoS₂ and identification of various functional groups and characteristic peaks (Mo bonding) was carried out using FTIR spectra. Micrographs obtained from FESEM and HR-TEM showed a sheet-like surface morphology, while agglomeration of nanosheets was observed upon doping with nanoparticles. To seek further clarity regarding the layered features of S–Mo–S planes, the defect densities and electronic band structure of pure MoS₂ and doped MoS₂ samples were investigated through Raman analysis. Optical properties of Zr-doped MoS₂ nanosheets were assessed using a UV-vis spectrophotometer and the results indicated a red-shift, i.e., movement of peaks towards longer wavelengths, of the material. Dynamics of migration and recombination of excited electron–hole pairs were investigated using PL spectroscopy, which was also used to confirm the presence of exfoliated nanosheets. In addition, the synthetic dye degradation potential of pure and doped samples was investigated in the presence of a reducing agent (NaBH₄). It was noted that doped MoS₂ showed superior catalytic activity compared to undoped MoS₂. The nanocatalyst synthesized in this study exhibited enhanced antibacterial activity against E. coli and S. aureus at high concentrations (0.5, 1.0 mg/50 μl). The present study suggests a cost-effective and environmentally friendly material that can be used to remove toxins such as synthetic dyes and tannery pollutants from industrial wastewater.

Nanostructured materials incorporated with biological reducing agents have shown significant potential for use in bactericidal applications.     

The effect of acute swim stress and training in the water maze on hippocampal synaptic activity as well as plasticity in the dentate gyrus of freely moving rats: Revisiting swim‐induced LTP reinforcement

Hippocampal long‐term potentiation (LTP) is a cellular model of learning and memory. An early form of LTP (E‐LTP) can be reinforced into its late form (L‐LTP) by various behavioral interactions within a specific time window (“behavioral LTP‐reinforcement”). Depending on the type and procedure used, various studies have shown that stress differentially affects synaptic plasticity. Under low stress, such as novelty detection or mild foot shocks, E‐LTP can be transformed into L‐LTP in the rat dentate gyrus (DG). A reinforcing effect of a 2‐min swim, however, has only been shown in (Korz and Frey (2003) J Neurosci 23:7281–7287; Korz and Frey (2005) J Neurosci 25:7393–7400; Ahmed et al. (2006) J Neurosci 26:3951–3958; Sajikumar et al., (2007) J Physiol 584.2:389–400) so far. We have reinvestigated these studies using the same as well as an improved recording technique which allowed the recording of field excitatory postsynaptic potentials (fEPSP) and the population spike amplitude (PSA) at their places of generation in freely moving rats. We show that acute swim stress led to a long‐term depression (LTD) in baseline values of PSA and partially fEPSP. In contrast to earlier studies a LTP‐reinforcement by swimming could never be reproduced. Our results indicate that 2‐min swim stress influenced synaptic potentials as well as E‐LTP negatively. © 2013 Wiley Periodicals, Inc.