Exploring the relationship between adolescent physical activity and anthropometric parameters

Purpose

To investigate the contribution of objectively measured light, moderate and vigorous physical activity to body mass index (BMI) and waist circumference-to-height ratio (WCHt) in adolescents.

Methods

A total of 694 adolescents (12–18 years) from six secondary schools in Auckland and two in Wellington, New Zealand, participated in the Built Environment and Physical Activity in New Zealand Adolescents study between February 2013 and September 2014. Light, moderate and vigorous intensity physical activity was objectively assessed using ActiGraph GT3X+ accelerometers, which were worn for an 8-day period. Participants’ weight, height and waist circumference were measured to calculate BMI and WCHt. Multiple linear regression was used to characterize independent continuous associations between the percentages of wear time spent in each physical activity intensity with BMI and WCHt.

Results

Vigorous activity was inversely independently associated with WCHt (R ² = 0.013, p < 0.01), whereas both light (R ² = 0.053, p < 0.01) and moderate (R ² = 0.036, p < 0.01) physical activity show significant, positive independent relationships with WCHt and BMI.

Conclusion

Only vigorous intensity physical activity was associated with key positive health outcomes in adolescents. Our data support the concept of emphasizing the importance of vigorous activity in youth physical activity guidelines.

     

Laboratory and field evaluation of the impact of exercise on the performance of regular and polymer-based deet repellents

Studies were done in Manitoba, Canada, to evaluate the impact of exercise on repellent performance against mosquitoes. Two products containing the active ingredient N,N-diethyl-3-methylbenzamide (deet) were tested; one product was a polymer-based cream (3M Ultrathon Insect Repellent) and the other product was an alcohol-based pump spray formulation (Muskol Insect Repellent). Assessments were done in the laboratory using Aedes aegypti (L.) and in the field with naturally occurring populations of mosquitoes. Repellent was applied to the forearms (laboratory) or a lower leg (field) of test subjects at 1.5 g of test product per 600 cm2 surface area (0.75 or 0.83 mg deet/cm2). For a given test day, subjects exercised or did not. Exposure to mosquito attack was for 1 min at 30-min intervals in laboratory procedures, and it was continuous in field tests. Performance was measured as complete protection time (CPT). Moderate levels of physical activity resulted in a >40% decline in mean CPT, from 468 to 267 min in the laboratory experiments and from 359 to 203 min in field tests. Repellent product did not affect the magnitude of the decline. Mean biting pressure during field trials was 21.3 bites per min, and mosquito collections were made up primarily of Ochlerotatus sticticus (Meigen) and Aedes vexans (Meigen).     

Microvascular studies in human radiation bowel disease.

The microvasculature was investigated in the normal bowel (n = 43 patients) and in radiation bowel disease (n = 18 patients). Tissue samples obtained from postoperative colectomy specimens in which the intramural vessels had been perfused with barium sulphate suspension were examined. Microradiography was used to study vascular pattern which was abnormal in radiation bowel disease. A recently described radiograph fluorescence system was used to estimate barium concentration, and hence microvascular volume. The radiation group showed a highly significant reduction in barium concentration (p less than 0.001), when compared with the normal group. This reduction was diffuse in samples from 15 patients who had received combined intracavity and external radiotherapy, but localised in two patients who had received intracavity treatment only. It is concluded that microvascular compromise is an important factor in the natural history of radiation bowel disease.     

Long term transvenous ventricular pacing in adults with congenital abnormalities of the heart and great arteries

Improved techniques of transvenous pacing have made it possible to use this approach in various congenital cardiac abnormalities. Transvenous active fixation pacing leads were implanted in seven patients aged 15 to 81 years with abnormal venous, atrioventricular, or ventriculoarterial connections with successful ventricular pacing.     

Rapid Detection and Simultaneous Antibiotic Susceptibility Analysis of Yersinia pestis Directly from Clinical Specimens by Use of Reporter Phage

Yersinia pestis is a tier 1 agent due to its contagious pneumopathogenicity, extremely rapid progression, and high mortality rate. As the disease is usually fatal without appropriate therapy, rapid detection from clinical matrices is critical to patient outcomes. We previously engineered the diagnostic phage ΦA1122 with luxAB to create a “light-tagged” reporter phage. ΦA1122::luxAB rapidly detects Y. pestis in pure culture and human serum by transducing a bioluminescent signal response. In this report, we assessed the analytical specificity of the reporter phage and investigated diagnostic utility (detection and antibiotic susceptibility analysis) directly from spiked whole blood. The bioreporter displayed 100% (n = 59) inclusivity for Y. pestis and consistent intraspecific signal transduction levels. False positives were not obtained from species typically associated with bacteremia or those relevant to plague diagnosis. However, some non-pestis Yersinia strains and Enterobacteriaceae did elicit signals, albeit at highly attenuated transduction levels. Diagnostic performance was assayed in simple broth-enriched blood samples and standard aerobic culture bottles. In blood, <10² CFU/ml was detected within 5 h. In addition, Y. pestis was identified directly from positive blood cultures within 20 to 45 min without further processing. Importantly, coincubation of blood samples with antibiotics facilitated simultaneous antimicrobial susceptibility profiling. Consequently, the reporter phage demonstrated rapid detection and antibiotic susceptibility profiling directly from clinical samples, features that may improve patient prognosis during plague outbreaks.     

Nonlinkage of D6S260, a putative schizophrenia locus,to bipolar affective disorder

To examine whether genes that predispose to schizophrenia also confer a predisposition to other psychiatric disorders such as bipolar affective disorder (BAD), we tested for linkage between the recently identified schizophrenia susceptibility locus D6S260 and the inheritance of BAD in 12 large Australian pedigrees. We found no evidence for linkage over a region of 12–27 cM from the D6S260 locus, depending on the model used. Our results therefore do not provide support for the continuum theory of psychosis. © 1996 Wiley-Liss, Inc.