Beeinflussung der Vorphase der Gerinnung durch Dextran 150

Zusammenfassung Infusionen von Dextran 150 beim Kaninchen führen zunächst zu einer Verkürzung derr-Zeit im Thrombelastogramm, einem Abfall der Thrombocyten und zu einer Verkürzung der Gerinnungszeiten im Thromboplastinbildungstest. Später lassen sich eine Verlängerung derr-Zeit im TEG sowie eine Verlängerung der Gerinnungszeiten im Thromboplastinbildungstest bei unveränderten Thrombocytenzahlen beobachten. Nach der wahrscheinlichkeitsstatistischen Prüfung läßt sich erwarten, daß diese Versuchsergebnisse reproduzierbar sind. Die Versuchsanordnung berechtigt zu der Annahme, daß Dextran 150 über das Kontaktprodukt die Gerinnung beeinflußt. Im weiteren Versuchsablauf wird ein Inhibitor nachweisbar, der die gesteigerten intravasalen Gerinnungsvorgänge hemmt. Die Beziehung zwischen diesem und anderen in der Literatur beschriebenen Gerinnungs-inhibitoren wird diskutiert.

---

Summary Infusion of Dextran 150 in rabbits induced in the beginning a shortening of ther-time in the thrombelastogram, a decline of the platelets and a shortening of the coagulation time in the thromboplastin formation test. Later a prolongation of ther-time in the TEG and a prolongation of the coagulation time in the thromboplastin formation test without further altering of the platelet count are seen. It might be assumed according to the statistical calculation of probabilities, that these datas can be reproduced. The tests used support the view that Dextran 150 influences the clotting system via a contactproduct. In the second part of the experiment there is evidence of an inhibitor which delays the increased intravascular process of coagulation. The connections between that and other inhibitors of clotting mechanism known in the literature are discussed.

     

Detailed per-oral small bowel examination vs. enteroclysis. Part II: Radiographic accuracy

Accuracy of the detailed per-oral small bowel series and enteroclysis was compared in 134 patients known to have (or not have) disease of the small bowel. Overall sensitivity of the per-oral examination was 92% and specificity 94%, compared to 94% and 89%, respectively, for enteroclysis. There was no difference between the two in Crohn disease, adhesions, and metastatic disease; however, enteroclysis was thought to be more effective in delineating peritoneal adhesions in patients with obstruction. The authors conclude that while the per-oral study and enteroclysis are equally valid methods of examining the small bowel, the per-oral study is preferable as a screening examination because it requires less time, has fewer side effects, and involves a lower radiation exposure.     

CVID-associated TACI mutations affect autoreactive B cell selection and activation

Common variable immune deficiency (CVID) is an assorted group of primary diseases that clinically manifest with antibody deficiency, infection susceptibility, and autoimmunity. Heterozygous mutations in the gene encoding the tumor necrosis factor receptor superfamily member TACI are associated with CVID and autoimmune manifestations, whereas two mutated alleles prevent autoimmunity. To assess how the number of TACI mutations affects B cell activation and tolerance checkpoints, we analyzed healthy individuals and CVID patients carrying one or two TACI mutations. We found that TACI interacts with the cleaved, mature forms of TLR7 and TLR9 and plays an important role during B cell activation and the central removal of autoreactive B cells in healthy donors and CVID patients. However, only subjects with a single TACI mutation displayed a breached immune tolerance and secreted antinuclear antibodies (ANAs). These antibodies were associated with the presence of circulating B cell lymphoma 6–expressing T follicular helper (Tfh) cells, likely stimulating autoreactive B cells. Thus, TACI mutations may favor CVID by altering B cell activation with coincident impairment of central B cell tolerance, whereas residual B cell responsiveness in patients with one, but not two, TACI mutations enables autoimmune complications.     

Multivariable analysis of heart rate recovery after cycle ergometry in heart failure: exercise in heart failure

Purpose

The purpose of this study was to investigate the association between impairment in heart rate recovery (HR_rec) after cycle ergometry and prognostic markers in patients with heart failure (HF) compared with healthy controls.

Methods

Fifty patients with chronic HF (systolic HF, N = 30; diastolic HF, N = 20; mean age = 62 ± 12 years) and 50 healthy controls (N = 50; mean age = 66 ± 13 years) underwent 2-dimensional and M-mode echocardiography followed by cardiopulmonary exercise testing. Independent predictors of HR_rec at 1 and 2 minutes after exercise were analyzed by univariable and multivariable regression analyses, and receiver operating characteristics were performed to obtain area under the curve.

Results

In HF, left ventricular end-diastolic diameter (millimeters), left ventricular ejection fraction (%), N-terminal pro-brain natriuretic peptide (picograms/milliliter), peak oxygen uptake (VO₂peak [milliliters/kilogram/min]), and peak heart rate (HR_peak) showed a significant association with HR_rec (beats/min) in univariate regression analyses (P < .001), but only VO₂peak remained independently predictive of both HR_rec1 (P = .034) and HR_rec2 (P = .008) in the multivariable regression analyses. In controls, VO₂peak (P = .035) and HR_peak (P = .032) were significantly associated with HR_rec2 in univariate analyses only. Optimal cutoff values for discriminating HF versus non-HF based on HR_rec were 17.5 beats/min (sensitivity 92%; specificity 74%) for HR_rec1 and 31.5 beats/min (sensitivity 94%; specificity 86%) for HR_rec2. Optimal cutoff values for discriminating systolic HF versus diastolic HF were 12.5 beats/min (sensitivity 78%; specificity 80%) for HR_rec1 and 24.5 beats/min (sensitivity 82%; specificity 90%) for HR_rec2.

Conclusion

Impairment in after exercise HR_rec is significantly and independently associated with VO2peak in HF and thus might constitute a useful tool for assessing the degree of functional status during exercise rehabilitation.     

Evaluation of the role of location and distance in recruitment in respondent-driven sampling

Background

The purpose of the project was to delineate a series of contiguous neighbourhood-based "Data Zones" within the Region of Peel (Ontario) for the purpose of health data analysis and dissemination. Zones were to be built on Census Tracts (N = 205) and obey a series of requirements defined by the Region of Peel. This paper explores a method that combines statistical analysis with ground-truthing, consultation, and the use of a decision tree.

Data

Census Tract data for Peel were derived from the 2006 Canadian Census Master file.

Methods

Following correlation analysis to reduce the data set, Principal Component Analysis was applied to the data set to reduce the complexity and derive an index. The Getis-Ord Gi*statistic was then applied to look for statistically significant clusters of like Census Tracts. A detailed decision tree for the amalgamation of remaining zones and ground-truthing with Peel staff verified the resulting zones.

Results

A total of 15 Data Zones that are similar with respect to socioeconomic and sociodemographic attributes and that met criteria defined by Peel were derived for the region.

Conclusion

The approach used in this analysis, which was bolstered by a series of checks and balances throughout the process, gives statistical validity to the defined zones and resulted in a robust series of Data Zones for use by Peel Public Health. We conclude by offering insight into alternative uses of the methodology, and limitations.