Bachelor completion and dropout rates of selected, rejected and lottery-admitted medical students in the Netherlands.

BACKGROUND: Evidence for the effectiveness of the selection of medical students is weak. This study aimed to examine the added value of a two-step selection procedure (first step non-academic, second step academic tests) to a pre-university GPA-based lottery procedure. Because previous research has suggested that participation in selection (regardless of the outcome) is a predictor of study success, this study is the first to include students who initially applied for selection, then refrained from (actively) participating in selection and were eventually admitted through lottery. METHODS: Bachelor completion and dropout rates of selected (n = 416) and lottery-admitted students from four cohorts (2006-2009) were compared using logistic regression analysis. Four groups of lottery-admitted students were distinguished: students who were rejected after step 2 (n = 57), were rejected after step 1 (n = 169), withdrew during selection step 1 (n = 42) and students who only applied for lottery (n = 366). Covariates included gender, age, pre-university GPA and cohort. RESULTS: There was a significant association between admission group and obtaining a bachelor degree in three years. Selected students were more likely to obtain a bachelor degree within three years (64.2% versus 51.6%; OR = 1.7) or four years (81.5% versus 74.3%; OR = 1.6) than students who only applied to a lottery (p <  0.05); selected students also seemed more likely to obtain all Year-1 course credits than students who withdrew during step 1 (40.4% versus 21.4%; OR = 2.3; p <  0.05). We found no significant association between dropout and admission groups. Students rejected at step 1 or 2 did not perform significantly different from selected students on any of the outcome measures. CONCLUSIONS: The findings indicated that students at risk for study delay in the preclinical phase in our context were more likely to refrain from applying to a demanding selection procedure when a less demanding alternative was available. We found no significant associations between the non-academic and academic selection steps and bachelor completion and dropout rates. These findings suggest that the presence of the selection was more important than these specific selection components. In follow-up research, we plan to investigate the associations between the admission groups and outcome measures in the clinical phase.

Blood-brain barrier alterations in both focal and diffuse abnormalities on postmortem MRI in multiple sclerosis.

Postmortem MRI-guided tissue sampling significantly enhances the yield of MS lesions in autopsy material, but so far it is unknown whether abnormalities concur with blood-brain barrier alterations. Here we sampled MS lesions with focal and diffuse abnormalities (diffusely abnormal white matter; DAWM) on MRI; both were coupled to the presence of MS lesions upon neuropathological examination. Extravascular distribution of fibrinogen, indicating BBB disturbance, was observed in so-called (p)reactive lesions that reflect discrete areas of microglial activation without demyelination within an otherwise normal appearing white matter. Leakage became more extensive in active demyelinating MS lesions to chronic inactive lesions. An enlargement of the perivascular (Virchow-Robin) space containing infiltrated leukocytes was associated with both DAWM and focal abnormalities on postmortem MRI. This study shows for the first time that in MS brain changes in the vasculature take place not only in focal lesions but also in DAWM as detected by postmortem MRI.

Matrix metalloproteinase-12 is expressed in phagocytotic macrophages in active multiple sclerosis lesions.

Matrix metalloproteinases (MMPs) are proteases involved in extracellular matrix (ECM) remodeling, leukocyte infiltration into lesions and myelin degradation in the central nervous system (CNS) disease multiple sclerosis (MS). We have investigated whether MMP-12 (macrophage metalloelastase) is expressed in MS lesions at various stages. In control patient tissue and (p)reactive MS lesions, only occasional microglial and astrocyte staining was detected. In contrast, in active demyelinating lesions, phagocytic macrophages were MMP-12 positive. A lower proportion of phagocytes was positive for MMP-12 in chronic active demyelinating lesions and inactive lesions. This suggests a role for MMP-12 during demyelination in MS.