Biomedical subjects

M G Vangel

Publications and source records attributed to M G Vangel.

5 recordsLinked to original sources

PubMed2006

Neuroanatomic correlates of stroke-related myocardial injury.

BACKGROUND: Myocardial injury can occur after ischemic stroke in the absence of primary cardiac causes. The neuroanatomic basis of stroke-related myocardial injury is not well understood. OBJECTIVE: To identify regions of brain infarction associated with myocardial injury using a method free of the bias of an a priori hypothesis as to any specific location. METHODS: Of 738 consecutive patients with acute ischemic stroke, the authors identified 50 patients in whom serum cardiac troponin T (cTnT) elevation occurred in the absence of any apparent cause within 3 days of symptom onset. Fifty randomly selected, age- and sex-matched patients with ischemic stroke without cTnT elevation served as controls. Diffusion-weighted images with outlines of infarction were co-registered to a template, averaged, and then subtracted to find voxels that differed between the two groups. Voxel-wise p values were determined using a nonparametric permutation test to identify specific regions of infarction that were associated with cTnT elevation. RESULTS: The study groups were well balanced with respect to stroke risk factors, history of coronary artery disease, infarction volume, and frequency of right and left middle cerebral artery territory involvement. Brain regions that were a priori associated with cTnT elevation included the right posterior, superior, and medial insula and the right inferior parietal lobule. Among patients with right middle cerebral artery infarction, the insular cluster was involved in 88% of patients with and 33% without cTnT elevation (odds ratio: 15.00; 95% CI: 2.65 to 84.79). CONCLUSIONS: Infarctions in specific brain regions including the right insula are associated with elevated serum cardiac troponin T level indicative of myocardial injury.

Aged↗

PubMed2005

fMRI of sensitization to angry faces.

This study examined what is communicated by facial expressions of anger and mapped the neural substrates, evaluating the motivational salience of these stimuli. During functional magnetic resonance imaging, angry and neutral faces were presented to human subjects. Across experimental runs, signal adaptation was observed. Whereas fearful faces have reproducibly evoked response habituation in amygdala and prefrontal cortex, angry faces evoked sensitization in the insula, cingulate, thalamus, basal ganglia, and hippocampus. Complementary offline rating and keypress experiments determined an aversive rank ordering of angry, fearful, neutral, and happy faces and revealed behavioral sensitization to the angry faces. Subjects rated angry faces, in contrast to other face categories such as fear, as significantly more likely to directly inflict harm. Furthermore, they rated angry faces as significantly less likely to produce positive emotional outcomes than the other face categories. Together these data argue that angry faces, a directly aversive stimulus, produce a sensitization response.

Adaptation, Psychological↗

PubMed2005

Case clustering in infective endocarditis: the role of availability bias.

Limited data exist regarding the impact of variations in clinical practice and physicians' cognitive bias on the diagnosis of infective endocarditis (IE). As an illustration of these effects, unexpected clustering of IE diagnosis was encountered in a prospectively studied cohort. Transoesophageal echocardiography examinations for suspected IE were performed more frequently following a diagnosis of IE, and were associated with a subsequent cluster of IE cases. The cognitive bias of physicians resulting from a recent case of IE can lead to a transient increase in diagnosing additional cases of IE.

Bias↗

PubMed2002

The influence of gender on survival and tumor recurrence following adjuvant therapy of completely resected stages II and IIIa non-small cell lung cancer.

This study evaluates the influence of gender on survival and tumor recurrence following adjuvant therapy of completely resected stages II and IIIa non-small cell lung cancer (NSCLC). The Eastern Cooperative Oncology Group conducted a randomized prospective trial of adjuvant therapy in patients with completely resected stages II and IIIa NSCLC. A laboratory correlative study assessed the prevalence and prognostic significance of p53 and K-ras mutations. Patients were randomized to receive either radiotherapy (RT) alone or four cycles of cisplatin and VP-16 administered concurrently with radiotherapy (CRT). Median survival was 35 months for the 285 men and 41 months for the 203 women enrolled in the study (P = 0.12). The relative risk (RR) of death for men vs women was 1.19 (95% confidence interval [CI], 0.95-1.49). Median survival of the 147 men and 95 women randomized to the RT arm was 39 months each (P = 0.35). Median survival of the 138 men and 108 women randomized to the CRT arm was 30 and 42 months, respectively (P = 0.18). Disease recurrence patterns were similar between the genders. Univariate and multivariate analyses demonstrated improved survival for women with tumors of non-squamous histology (P < 0.01). The distribution of p53 and K-ras mutations was similar between the genders and had no influence on survival. Gender does not influence survival following adjuvant RT or CRT administered to patients with completely resected stages II and IIIa NSCLC. However, women with non-squamous histology have increased survival when compared to men.

Adult↗

PubMed1999

Maximum likelihood analysis for heteroscedastic one-way random effects ANOVA in interlaboratory studies.

This article presents results for the maximum likelihood analysis of several groups of measurements made on the same quantity. Following Cochran (1937, Journal of the Royal Statistical Society 4(Supple), 102-118; 1954, Biometrics 10, 101-129; 1980, in Proceedings of the 25th Conference on the Design of Experiments in Army Research, Development and Testing, 21-33) and others, this problem is formulated as a one-way unbalanced random-effects ANOVA with unequal within-group variances. A reparametrization of the likelihood leads to simplified computations, easier identification and interpretation of multimodality of the likelihood, and (through a non-informative-prior Bayesian approach) approximate confidence regions for the mean and between-group variance.

Analysis of Variance↗