Platelet factor 4/heparin antibodies in blood bank donors

Platelet factor 4 (PF4)/heparin antibody, typically associated with heparin therapy, is reported in some heparin-naive people. Seroprevalence in the general population, however, remains unclear. We prospectively evaluated PF4/heparin antibody in approximately 4,000 blood bank donors using a commercial enzyme-linked immunosorbent assay for initial and then repeated (confirmatory) testing. Antibody was detected initially in 249 (6.6%; 95% confidence interval [CI], 5.8%-7.4%) of 3,795 donors and repeatedly in 163 (4.3%; 95% CI, 3.7%-5.0%) of 3,789 evaluable donors. "Unconfirmed" positives were mostly (93%) low positives (optical density [OD] = 0.40-0.59). Of 163 repeatedly positive samples, 116 (71.2%) were low positives, and 124 (76.1%) exhibited heparin-dependent binding. Predominant isotypes of intermediate to high seropositive samples (OD >0.6) were IgG (20/39 [51%]), IgM (9/39 [23%]), and indeterminate (10/39 [26%]). The marked background seroprevalence of PF4/heparin antibody (4.3%-6.6%) with the preponderance of low (and frequently nonreproducible) positives in blood donors suggests the need for further assay calibration, categorization of antibody level, and studies evaluating clinical relevance of "naturally occurring" PF4/heparin antibodies.     

Power output of legs during high intensity cycle ergometry: Influence of hand grip

Traditionally, leg cycle ergometry is used to assess the power output of the lower limbs. However, it is suspected that the upper body makes a significant, albeit as yet unknown, contribution to the measured power output, and as such, the lean mass of the whole body should be considered during ergometric assessment. To test this idea, indices of mechanical power output were obtained from 11 subjects during high intensity leg cycle ergometry tests (20 second duration; 75 grams per kilogram total body mass) using two protocols: one with a standard handle-bar grip (with grip) and one with supinated wrists (without-grip). Peak mechanical power, mean mechanical power, fatigue index and total mechanical work values were calculated for each subject during each test and the sample mean differences associated with the two protocols were compared using paired Student t-tests. The with-grip protocol yielded significantly greater peak mechanical power output than the without-grip protocol (886+/-124 W and 815+/-151 W, respectively), suggesting a significant upper body contribution to the maximum power output measured for the legs. As a first step towards quantifying the upper body involvement during leg cycle ergometry, surface electromyography of the forearm musculature was measured in a twelfth subject whilst performing each of the test protocols. During the with-grip ergometer tests, the intensity of electrical activity in the forearm musculature was similar, if not greater than, the intensity of electrical activity recorded for the forearm musculature during 100% maximum voluntary hand grip-dynamometer contractions, suggesting maximum isometric-type forearm muscle contraction during the with-grip leg ergometry tests. These findings suggest that the performance of traditional-style leg cycle ergometry requires a muscular contribution from the whole body. As such, researchers should be mindful of this, both in terms of the allocation of ergometer loads, and in the analysis of blood-borne metabolites.     

The Prevalence and Correlates of Involvement in the Criminal Justice System Among Youth on the Autism Spectrum

This study examined the prevalence and correlates of involvement in the criminal justice system among a nationally representative sample of youth with autism. We examined whether youth had been stopped and questioned by police or arrested at 14–15 years old and 21–22 years old. By age 21, approximately 20% of youth with autism had been stopped and questioned by police and nearly 5% had been arrested. Female youth were less likely to be involved in the criminal justice system, whereas youth displaying externalizing behaviors were more likely to be involved in the criminal justice system. Further research is needed to investigate factors associated with involvement in the criminal justice system among youth with autism and to implement prevention strategies.     

Reliability of the measurement of intrarenal haemodynamics in the dog,as determined by the radioactive microsphere technique

In the anaesthetized dog total renal blood flow (RBF) and its intrarenal distribution were investigated by the radioactive microsphere technique under control conditions and after various experimental interventions.

1. In five control series performed within the last four years, there was a small but significant scatter in total RBF, due entirely to changes in inner cortical (IC) perfusion, while outer cortical (OC) perfusion proved to be constant.
2. Repeated measurements in the same dog, performed after 1 h interval, revealed constancy of total RBF with some inward shifting in cortical perfusion.
3. Surgical intervention or manipulation of the kidney did not alter total RBF but led to an increase in IC, compensated by a decrease in OC perfusion.
4. The possible role of local intrarenal hormones (angiotensin and prostaglandin) in the above changes is discussed.

     

Anxiety sensitivity,distress tolerance,and discomfort intolerance in relation to coping and conformity motives for alcohol use and alcohol use problems among young adult drinkers

Anxiety sensitivity, distress tolerance, and discomfort intolerance have been identified as important factors related to alcohol use motives and alcohol-related problems. Yet, these variables are highly correlated and little work has delineated whether these psychological vulnerability factors are differentially related to alcohol use motives and problems. To fill this gap in the existing literature, the present study evaluated whether anxiety sensitivity, distress tolerance, and discomfort intolerance were differentially related to high-risk alcohol use motives (i.e., coping and conformity motives) and alcohol use problems among 224 young adult, current drinkers (52.3% women; M_age = 21.18, SD = 7.08). Results indicated that distress tolerance, but not anxiety sensitivity or discomfort intolerance, was significantly related to coping motives for alcohol use. Additionally, anxiety sensitivity, but not distress tolerance or discomfort intolerance, was significantly related to conformity motives for drinking. For both sets of analyses, the observed significant effects were evident above and beyond the variance accounted for by alcohol consumption level, smoking rate, negative affectivity, and non-criterion alcohol use motives. Additionally, discomfort intolerance and anxiety sensitivity each predicted alcohol use problems; effects were not attributable to negative affectivity, cigarettes smoked per day, or shared variance with distress tolerance. Findings are discussed in relation to the role of emotional sensitivity and intolerance in terms of the motivational bases for alcohol use and alcohol use problems among young adult drinkers.