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Intervertebral disc (IVD) degeneration (IVDD) leads to structural and functional changes. Biomaterials for restoring IVD function and promoting regeneration are currently being investigated; however, such approaches require validation using animal models that recapitulate clinical, biochemical, and biomechanical hallmarks of the human pathology. Herein, we comprehensively characterized a sheep model of chondroitinase-ABC (C-ABC) induced IVDD. Briefly, C-ABC (1U) was injected into the L1/2, L2/3, and L3/4IVDs. Degeneration was assessed via longitudinal magnetic resonance (MR) and radiographic imaging. Additionally, kinematic, biochemical, and histological analyses were performed on explanted functional spinal units (FSUs). At 17-weeks, C-ABC treated IVDs demonstrated significant reductions in MR index (p=0.030) and disc height (p=0.009) compared to pre-operative values. Additionally, C-ABC treated IVDs exhibited significantly increased creep displacement (p=0.004) and axial range of motion (p=0.007) concomitant with significant decreases in tensile (p=0.034) and torsional (p=0.021) stiffnesses and long-term viscoelastic properties (p=0.016). C-ABC treated IVDs also exhibited a significant decrease in NP glycosaminoglycan: hydroxyproline ratio (p=0.002) and changes in microarchitecture, particularly in the NP and endplates, compared to uninjured IVDs. Taken together, this study demonstrated that intradiscal injection of C-ABC induces significant degeneration in sheep lumbar IVDs and its potential for use in evaluating biomaterials for IVD repair.Statement of SignificanceSelecting the appropriate model for assessing biomaterials to repair and/or support regeneration of the intervertebral disc (IVD) has been controversial, leading to the use of many methods of simulating IVD degeneration (IVDD) in multiple species. Many of these models lack thorough characterization of their fidelity to human IVDD, which could hinder the translation of novel biomaterials and therapies due to unknown confounding factors. Herein, further investigation of one such model was performed using the matrix-degrading enzyme chondroitinase-ABC to induce degeneration in sheep lumbar IVDs. Degenerative changes were quantified using outcome measures relevant to human IVDD, and this dosage and method induces an aggressive degeneration environment that could be used to assess biomaterials that mimic the structure and function of the entire composite IVD. These findings may aid investigators in their selection of an appropriate animal model for preclinical testing of biomaterials and other therapeutics.

PURPOSE: Empathy tends to decline during medical education, typically beginning in the third year of medical school and often continuing throughout residency and the physician’s medical career. The purpose of this study was to determine if first year medical student empathy is affected by small group interactions with patients with neurological disorders, and to investigate if changes in empathy persisted over time. MATERIALS AND METHODS: Eighty first year medical students participating in a Neuroscience Module interacted with a variety of neurological patients in a small group informational session. Prior to the experience, participants completed the Jefferson Scale of Physician Empathy–Student (JSPE-S) version. After the experience, students completed a post-test JSPE-S questionnaire, and a final post-post-test JSPE-S questionnaire was completed 5 weeks later. Empathy scores were compared with a repeated measures MANOVA. The relationship between gender and empathy, and the effect of the age of the neurological patients on empathy scores were also examined. RESULTS: Empathy scores for seventy-one students who completed the JSPE-S questionnaires were analyzed. Students had significantly higher empathy immediately after the patient interaction experience, and the change in empathy was sustained over the course of 5 weeks (p = 0.015). The age of the neurological patients had a significant effect on empathy scores. There was no significant difference between empathy scores and gender. CONCLUSIONS: This study supports the incorporation of a group patient interaction experience into the medical school curriculum as an inexpensive and practical method of enhancing medical student empathy in a non-clinical setting.

BACKGROUND: The integration of patient encounters into the first year of the medical school curriculum is known to be of vital importance in the development of critical thinking and communication skills. We investigated whether exposure of first year medical students to patient encounters during a first year medical school neuroscience course result in a high level of motivation associated with the clinical encounter, and whether this high level of motivation translates to higher academic performance as measured by their performance on formative and summative examinations. METHODS: First year medical students interacted with patients presenting with different neurological disorders in a small group informal session. Following the small group interactions with patients, students participated in a large group debriefing session involving discussions with peers, biomedical sciences faculty, and clinicians. Students then completed a survey designed to assess their motivation in correspondence with the Attention, Relevance, Confidence, and Satisfaction (ARCS) model of motivation. These results were then correlated with students’ performance in the neuroscience examinations. RESULTS: The total mean score was high for all categories of the ARCS model of motivation (4.26/5) and was highest for Relevance (4.46/5). When these motivation scores were correlated with students’ performance on the formative and summative examinations, a significant positive correlation was found between motivation and performance on both the formative (r = 0.85) and summative (r = 0.95) neuroscience examinations. CONCLUSION: Encounters with patients presenting with neurological disorders during a first year medical neuroscience course result in a high level of motivation associated with the clinical encounter, and this was positively correlated with their academic performance.

The treatment outcomes in the use of rt-PA have been reported. Some studies reported worse outcome in women than men, while others presented opposing data. Using data from a hospital-based stroke registry, we investigated evidence of gender difference and determined exclusion criteria in a stroke population with incidence of hypertension.In a stroke population of women and men with incident of hypertension from a stroke registry, demographics and clinical factors were compared. Univariate analysis was used to determine gender differences, while multivariable models adjusted for demographic and clinical variables.Among the 669 stroke patients with incident of hypertension that were excluded from rt-PA treatment, 362 were female and 307 were male. Female patients with increasing age (OR = 0.956-0.984, P 0.001), diabetes mellitus (OR = 0.095-0.559, P = 0.001), higher NIH stroke scale score (OR = 1.019-1.090, P = 0.002), previous stroke (OR = 0.337-0.850, P = 0.008), diabetes medication (OR = 1.200-7.724, P = 0.019), and INR (OR = 0.033-0.597, P = 0.008) are more likely to be excluded. Male patients with a history of a previous stroke (OR = 0.265-0.704, P = 0.001), risk of mortality (OR = 0.803-0.950, P = 0.002), higher NIH stroke scale score(OR = 1.101-1.276, P 0.001), cholesterol reducing medication (OR = 1.191-2.910, P = 0.006), weakness at presentation(OR = 1.207-4.421, P = 0.011), and INR (OR = 0.016-0.243, P 0.001) are more likely to be excluded.Women have a worse outcome than men in an untreated acute ischemic stroke population, but when treated, women have a better treatment outcome compared to men. In a hypertensive stroke population, the clinical variables for the exclusion criteria for women and men are significantly different, even after adjustment for confounding variables.

In a stroke population, women have a worse outcome than men when untreated. In contrast, there is no significant difference in treated patients. In this study, we determined whether clinical variables represent a promising approach to assist in the evaluation of gender differences in a stroke population.We analyzed data from ischemic stroke patients' ≥18 years-old from the stroke registry on rtPA administration and identified gender differences in clinical factors within inclusion and exclusion criteria in a stroke population that received rtPA. Multivariate analysis was used to adjust for patient demographic and clinical variables.Of the 241 eligible stroke patients' thrombolytic therapy, 49.4% were females and 50.6% were males. Of the 422 patients that did not receive rtPA, more women (235) were excluded from rtPA than men (187) (P0.05). In the male population, exclusion from rtPA was associated with history of a previous stroke (P0.05, OR=2.028), hypertension (P0.05, OR=0.519), and NIH stroke score (P0.0001, OR=0.893). In female stroke patients, exclusion from rtPA was associated with previous history of stroke (P0.05, OR=2.332), diabetes (P0.05, OR=1.88) and NIH stroke score (P0.05, OR=0.916).Despite similarities in different areas of stroke care for both men and women, more women with diabetes, previous history of stroke and higher NIH scores are more likely to be excluded from thrombolytic therapy. Men with a previous history of stroke, hypertension and higher NIH scores are more likely to be excluded rtPA even after adjustment for confounding variables.

Students’ perceptions of the effectiveness of their interaction with patients is known to be correlated with their performance in the clinical rotations. Whether such an experience is correlated with the academic performance in a year one neuroscience course is not clear. Year one medical students were allowed to interact in small groups with patients suffering from neurological diseases. The small group sessions were followed by a large group debriefing session to discuss their experience following the patient interaction. Students were administered two structured surveys, a pre-test and a post-test, to evaluate their pre-session expectations and post-session satisfaction with their interaction with patients. The post-test survey results were correlated by objective with formative and summative examination scores. There was a positive correlation between students’ perceptions of the effectiveness of their interaction with patients and their performance on the formative examination (R2 = 0.315). The correlation was higher and significant (R2 = 0.774) between students’ interaction with patients and the summative examination. For students’ perception of the interaction with patients, questions on integration of the nervous system (OR = 3.449, p = 0.002), analytical and imaging modalities (OR = 1.513, p = 0.045), and abnormalities in the nervous system (OR = 2.117, p = 0.034) were significantly associated with students’ satisfaction of their interaction with patients. When a similar analysis was performed on the summative examination, five learning objectives revealed significant association: integrated functions of the nervous system (OR = 3.617, p = 0.005), structure of the nervous system (OR = 1.961, p = 0.021), analytical and imaging modalities (OR = 2.212, p = 0.031), orientation of anatomical features (OR = 1.512, p = 0.037), and abnormalities in the nervous system (OR = 2.413, p = 0.002). Interaction with patients with neurological diseases was positively correlated with the students’ academic performance.

Our ongoing subjective experiences, and our memories of those experiences, are shaped by our prior experiences, goals, and situational understanding. These factors shape how we allocate our attentional resources over different aspects of our ongoing experiences. These attentional shifts may happen overtly (e.g., when we change where we are looking) or covertly (e.g., without any explicit physical manifestation). Additionally, we may attend to what is happening at a specific spatial location (e.g., because we think something important is happening there) or we may attend to particular features irrespective of their locations (e.g., when we search for a friends face in a crowd). We ran two covert attention experiments that differed in how long they asked participants to maintain the focus of the features or locations they were attending. Later, the participants performed a recognition memory task for attended, unattended, and novel stimuli. Participants were able to shift the location of their covert attentional focus more rapidly than they were able to shift their focus of covert attention to stimulus features, and the effects of location-based attention on memory were longer-lasting than the effects of feature-based attention.