Evaluating the Impact of a Problem-Based Learning Curriculum on Undergraduate Medical Students in Saudi Arabia

The main aim of this study was to examine in detail the benefits and problems of introducing a different method of teaching to medical education, namely the problem-based learning (pBL) method. This technique, in a number of pieces of research, has been shown to be more effective than lecture-based method in fostering better critical-thinking, problem solving, and the self-directed learning skills of students, and also to enhance the acquisition and retention of knowledge. But PBL has not been universally successful. Despite this it has being recommended by medical educators worldwide; yet it remains to be formally evaluated in Saudi Arqbia. To evaluate the impact of PBL to students in particular and to Saudi Arabia in general, a test JiUn of the method was carried out, in which four Saudi medical colleges were selected to participate. The total number of subjects was 484, comprising 232 pre-clinical students (pre-CS) and 252 clinical students (CS) ;from five courses (units/modules) in the medical curriculum. A human genetics module was used as a case subject for the test run, and both pre-clinical and clinical students were assigned randomly to either a PBL or a lecturebased curriculum (LBC) group. Data was collected using six instruments which assessed knowledge, attitude, learning styles and perceptions of students in order to test fourteen hypotheses regarding the benefits of PBL to Saudi undergraduate medical students compared to LBC. Both qualitative and quantitative methods were used to collect and analyze the data. Qualitative data included essay-type written response from students, which was analyzed using Nvivo. For the quantitative data analysis, several analytical procedures within SPSS were employed. These included descriptive and ChiSquared Statistics, Univariate analysis, One-Way and Two-Way ANOVAs and Effect Size calculations. From the randomized controlled trial undertaken on pre-clinical and clinical students, very large differences were found in the outcomes for the two groups. Within the pre-clinical students, those in the PBL group scored significantly lower than those in the LBC group on every indicator of perceived knowledge, learning or examination results. For the clinical students, those in the PBL group scored significantly higher than those in the LBC group; these positive effects of PBL did not include learning outcomes, however. Of the fourteen hypotheses stated, highlighting the benefits of the PBL approach to Saudi undergraduate medical students, none was supported with respect to pre-clinical students, while nine were supported with respect to clinical students. This brought out a large difference between Saudi Arabian pre-clinical and clinical students in response to the intervention of the PBL approach compared to the lecture-based teaching method. These quantitative findings were supported by the qualitative data. Some of the central tenets of PBL are that it enhances knowledge retention, self-directed learning skills and level of motivation. These central tenets were not supported among Pre-CS; however, they were supported by results from CS. The use of PBL was associated with a change in motivating factors from purely selfachievement to the success of the group and shared knowledge. The finding that PBL was significantly valued by CS but not by Pre-CS is discussed in relation to literature written about education and explained by drawing on the distinction between 'transitional semi-PBL' (as experienced by the Pre-CS) and 'rigorously problem-based learning' (as experienced by the CS). This discussion leads to the proposal of an experiential-based learning model (PEBL), which is described in terms of its rationale, its major features and a means for its introduction into the colleges of medicine in Saudi Arabia.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A comparison study of histochemical staining of various tissues after Carnoy’s and formalin fixation

Background: The potential problems related to the use of formalin in histopathology, such as health hazards, deterioration of nuclei acids are well-known. The aim of this study was to evaluate the utilization of a Carnoy’s solution fixation in comparison with formalin on subsequent tissue sectioning and histochemical staining.Materials and Methods: Corresponding sections of 25 tissue biopsies of rabbit’s different organs were fixed in Carnoy’s solution and in 10% neutral buffered formalin. Samples were processed using the conventional method and then stained applying five histochemical methods. The degree ofthe quality of the staining was assessed for each method by scoring system (1-10) depending on comparison of the stained tissue sections with illustrated photomicrographs.Results: For the quality of cutting, the best quality was obtained by Formalin (mean = 4.76) then Carnoy’s fixative (mean =3.84). The best quality of Haematoxylin and Eosin staining was obtained by formalin (mean =5.28) then Carnoy's (mean = 4.00). For Alcian blue and Perl’s Prussian blue, the best staining qualities were obtained by Formalin (mean = 4.76 and 5.64 respectively) followed by Carnoy's (mean = 2.88 and 3.92 respectively). For periodic Acid Schiff's the best staining qualitywas obtained following Carnoy's fixation (mean = 4.52) then, the formalin (mean = 3.76).Conclusion: Although, Carnoy’s fluid is a safe fixative and can rapidly penetrate the tissues, but it can’t be a substitute for formalin.Keywords: Haematoxylin, photomicrographs, Eosin staining

Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion: A Comprehensive Literature Review

Dorsal root entry zone (DREZ) lesioning is a neurosurgical procedure that aims to relieve severe neuropathic pain in patients with brachial plexus avulsion by selectively destroying nociceptive neural structures in the posterior cervical spinal cord. Since the introduction of the procedure over 4 decades ago, the DREZ lesioning technique has undergone numerous modifications, with a variety of center- and surgeon-dependent technical differences and patient outcomes. We have reviewed the literature to discuss reported methods of DREZ lesioning and outcomes

Regulation of Stem Cell Proliferation and Cell Fate Specification by Wingless/Wnt Signaling Gradients Enriched at Adult Intestinal Compartment Boundaries

Intestinal stem cell (ISC) self-renewal and proliferation are directed by Wnt/β-catenin signaling in mammals, whereas aberrant Wnt pathway activation in ISCs triggers the development of human colorectal carcinoma. Herein, we have utilized the Drosophila midgut, a powerful model for ISC regulation, to elucidate the mechanisms by which Wingless (Wg)/Wnt regulates intestinal homeostasis and development. We provide evidence that the Wg signaling pathway, activation of which peaks at each of the major compartment boundaries of the adult intestine, has essential functions. Wg pathway activation in the intestinal epithelium is required not only to specify cell fate near compartment boundaries during development, but also to control ISC proliferation within compartments during homeostasis. Further, in contrast with the previous focus on Wg pathway activation within ISCs, we demonstrate that the primary mechanism by which Wg signaling regulates ISC proliferation during homeostasis is non-autonomous. Activation of the Wg pathway in absorptive enterocytes is required to suppress JAK-STAT signaling in neighboring ISCs, and thereby their proliferation. We conclude that Wg signaling gradients have essential roles during homeostasis and development of the adult intestine, non-autonomously controlling stem cell proliferation inside compartments, and autonomously specifying cell fate near compartment boundaries

Soluble TWEAK and Cardiovascular Morbidity and Mortality in Chronic Kidney Disease Patients

Introduction: Cardiovascular disease (CVD) is a major cause of morbidity and mortality in chronic kidney patients (CKD). The aim of this study was to demonstrate the role of soluble tumor necrosis factor (TNF) weak inducer of apoptosis (sTWEAK) as a marker of cardiovascular morbidity and mortality in CKD patients.Methods: The study included 75 CKD patients classified according to eGFR into three groups; group-1 included 15 patients with stage-1 CKD, group-2 included 30 patients with stage-2 and stage-3 CKD, and group-3 included 30 patients with stage-4 and stage-5 CKD. The three groups were compared to 20 matched controls. Interleukin-6 (IL-6) and sTWEAK were measured using ELISA and chemiluminescent techniques respectively. Carotid intima-media thickness (IMT) was also measured.Results: We found that IL-6 showed significant difference between patient groups and controls, being highest in stage 4 and 5 CKD patients and lowest in controls. Soluble TWEAK showed significant difference between patient groups and controls, being lowest in stage 4 and 5 CKD patients and highest in controls. Soluble TWEAK level showed significant negative correlation with IL-6 (r = -0.68; P<0.01) and carotid IMT (r = -0.95; P<0.01). After two years follow up, nine out of 75 CKD patients developed ischemic heart disease (IHD). Two patients developed cerebrovascular stroke and another patient developed peripheral arterial disease. These patients had significantly lower levels of sTWEAK at baseline compared to other patients (160.5± 60.2 versus 274.8±90 pg/mL; P < 0.05).Conclusion: Soluble TWEAK can be a novel biomarker of atherosclerosis and endothelial dysfunction as well as cardiovascular outcome in CKD patients

Erect Wing Facilitates Context-Dependent Wnt/Wingless Signaling by Recruiting the Cell-Specific Armadillo-TCF Adaptor Earthbound to Chromatin

During metazoan development, the Wnt/Wingless signal transduction pathway is activated repetitively to direct cell proliferation, fate specification, differentiation and apoptosis. Distinct outcomes are elicited by Wnt stimulation in different cellular contexts; however, mechanisms that confer context specificity to Wnt signaling responses remain largely unknown. Starting with an unbiased forward genetic screen in Drosophila, we recently uncovered a novel mechanism by which the cell-specific co-factor Earthbound 1 (Ebd1), and its human homolog jerky, promote interaction between the Wnt pathway transcriptional co-activators B-catenin/Armadillo and TCF to facilitate context-dependent Wnt signaling responses. Here, through the same genetic screen, we find an unanticipated requirement for Erect Wing (Ewg), the fly homolog of the human sequence-specific DNA-binding transcriptional activator nuclear respiratory factor 1 (NRF1), in promoting contextual regulation of Wingless signaling. Ewg and Ebd1 functionally interact with the Armadillo-TCF complex and mediate the same context-dependent Wingless signaling responses. In addition, Ewg and Ebd1 have similar cell-specific expression profiles, bind to each other directly and also associate with chromatin at shared genomic sites. Furthermore, recruitment of Ebd1 to chromatin is abolished in the absence of Ewg. Our findings provide in vivo evidence that recruitment of a cell-specific co-factor complex to specific chromatin sites, coupled with its ability to facilitate Armadillo-TCF interaction and transcriptional activity, promotes contextual regulation of Wnt/Wingless signaling responses