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Background: About 35% of the global burden of disease has roots in adolescence. Health in adolescence is an important determinant of health in adulthood., Objectives: This study aimed to generate risk scores for lifestyle behaviors among adolescents and to estimate the country-specific prevalence of these risk scores. The study also examined the relations of lifestyle risk scores with overweight or obesity among adolescents., Methods: We used the most recent data available from 20 nationally representative Global School-based Student Health Surveys. Our analytical sample size was 51,597. The outcome of interest was overweight or obesity. We developed 4 lifestyle risk scores (dietary habits, physical activity, sedentary behavior, and tobacco use), which were used as the exposure variables in this study. Multilevel logistic regression models were used to estimate adjusted ORs with 95% CIs., Results: In total, 18.2% of the participants were overweight or obese. Across countries, the percentage of adolescents with unhealthy dietary habits ranged from 76.7% (the Cook Islands) to 94.2% (Timor-Leste), physical inactivity ranged from 47.5% (Bangladesh) to 90.1% (the Philippines), and sedentary behavior ranged from 34.5% (Nepal) to 88.2% (Kuwait). Girls engaged in less physical activity than did boys. Increased odds of overweight or obesity were found among participants with high risk scores for physical inactivity (OR: 1.19; 95% CI: 1.11, 1.27) and for unhealthy sedentary behavior (OR: 1.25; 95% CI: 1.16, 1.35) compared with participants with low risk scores. Girls with high tobacco risk scores had higher odds (OR: 1.30; 95% CI: 1.02, 1.65) of overweight or obesity than did girls with low risk scores for tobacco use, whereas there were no significant differences in risk in boys., Conclusions: Unhealthy lifestyle behaviors were quite prevalent among adolescents, and higher lifestyle risk scores increased the risk of overweight or obesity., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society for Nutrition.)

Purpose: The intent of the study was to determine whether ultrasonic tissue characterization (UTC) could indicate acuteness and stability of deep venous thrombosis (DVT) of the lower extremities., Methods: Thrombi presenting as filling defects on color Doppler imaging in the common or superficial femoral or popliteal veins in 50 extremities in 45 patients with DVT were studied. Acute DVT was less than 4 days duration, and chronic DVT was greater than 21 days duration. UTC analysis of parameters from the normalized power spectrum of backscattered ultrasound signals from venous filling defects was performed. This spectrum approaches a straight line, and its basic parameters, slope, and Y-intercept are related to scatterer size, concentration, and the square of the scatterer-to-medium acoustic impedances. Ten of the DVT extremities were reexamined at 1 week to assess UTC changes that would indicate thrombus instability., Results: Acute DVT (19 of the 50 extremities) could be distinguished from chronic DVT, mainly on the basis of significantly higher intercept values for the acute group, which were 11.6 relative decibels (dBr) higher than those of the chronic DVT group. Discriminant linear analysis of the two parameters indicated a sensitivity of 94.7% and specificity of 90.3% in correctly diagnosing acute DVT. In a small sample of 10 extremities reexamined at 1 week, acute DVT extremities showed a mean 9.4 dBr decrease in intercept values with no significant change in slope., Conclusions: UTC distinguished clinically defined acute from chronic DVT. In a small series of extremities, UTC revealed significant instability of acute thrombi in a selected patient population.

Purpose: A venous thrombosis animal model demonstrated similarities between intimal hyperplasia and thrombus organization. This has prompted the evaluation of a hypothesis that intimal hyperplasia may be the mechanism for thrombus organization in veins with normal pressure., Methods: Thrombi were produced in surgically exposed jugular veins of anesthetized, 18 to 20 kg pigs. Thrombosis was induced by a combination of devascularization, electric injury produced by a low amperage, direct current, and permanent partial ligation (50% diameter reduction). Vein segments were harvested at 0, 1, 2, 7, 14, and 60 days and histologically examined for fibrin, red blood cells, platelets, smooth muscle cells, endothelial cells, elastic fibers, and collagen deposits., Results: Forty vein segments in 20 pigs were evaluated. Luminal thrombi with thickened walls developed in all specimens. All luminal thrombi demonstrated partial spontaneous thrombolysis over the period of observation. Intimal thickening consisting primarily of smooth muscle cells by day 2 was apparent and progressed until about 2 weeks, when collagen deposits became prominent within the neointima. The neointima frequently comprised half the cross-sectional area of the veins. Endothelial cells were present in the intima as single cells or as lining for clefts formed within the thickened intima., Conclusions: Smooth muscle cell proliferation with collagen deposition characteristic of intimal hyperplasia seemed to be the mechanism of thrombus organization in the experimental thrombosis model used in this study in which extensive stimulation was used to produce thrombosis.

Purpose: The ability of ultrasonic tissue characterization based on radiofrequency signal processing to detect compositional differences in thrombi of varying ages was evaluated in vivo., Methods: Thrombi were produced in 49 jugular veins of 26 anesthetized 18 to 20 kg pigs by partial ligation and application of direct electric current. Thrombi were imaged 30 minutes after formation and 1, 7, and 14 days later with a color Doppler ultrasound scanner that identified the thrombi, and acquired radio frequency data for ultrasonic tissue characterization analysis. Ultrasonic tissue characterization used two parameters from the normalized power spectrum, slope, and intercept, which are related to scatterer size, scatterer concentration, and acoustic-impedance differences between scatterers and surrounding medium. Previous in vitro studies demonstrated that lower slope and higher intercept values correlated with greater cellularity and more-dense fibrin mesh. Histologic examination was performed for each time period. The values of slope and intercept for each timed observation were compared by a multilinear discriminant analysis., Results: There were no statistical differences between day 0 and day 1. Statistically-significant differences in ultrasonic tissue characterization parameters were seen between all other time intervals with p values < 0.01. Older thrombi tended to demonstrate higher slope and lower intercept values. These ultrasonic tissue characterization changes correlated with a red cell and fibrin-mesh density reduction, which was confirmed by histologic findings and was indicative of partial spontaneous thrombolysis. The degree of spontaneous thrombolysis provides an estimate of the age of thrombi., Conclusion: Ultrasonic tissue characterization is capable of distinguishing age differences in thrombi in an animal model and has the potential for noninvasive application in clinical diagnosis.

This report describes the natural history of unrepaired minor technical defects detected by intraoperative B-mode ultrasonography during carotid endarterectomy. Intraoperative ultrasonography was used to assess the technical adequacy of 80 carotid endarterectomies. Sixty-two arteries were normal on intraoperative ultrasound examination, whereas the remaining 18 arteries had a total of 21 minor residual technical defects. The 21 minor defects consisted of four internal carotid artery lesions, nine common carotid artery lesions, and eight external carotid artery lesions, 19 had 1 to 3 mm intimal flaps, and two had small stenoses. Sixteen of the 19 intimal flaps resolved before the first postoperative ultrasound study. These arteries had normal examination results, which indicated that these intimal flaps had healed. The two stenoses detected intraoperatively could not be detected by postoperative carotid duplex scanning at 1 month follow-up. No statistically significant relationship was found between the presence of a minor residual defect on intraoperative ultrasonography and the subsequent development of recurrent stenosis or occlusion in any of the arteries assessed. These data suggest that certain minor technical defects in the carotid artery that were detected by intraoperative ultrasonography are benign and may not require repeat exploration of the carotid artery for repair.

The change in venous function during the course of the day was studied noninvasively in 50 normal lower extremities of 25 physically active normal subjects. Venous refilling time, measured by photoplethysmography, was significantly shorter (p less than 0.0001), and venous capacitance, measured by impedance plethysmography, was significantly reduced (p less than 0.04) after 5 hours or more of daily activities performed in the upright position. Abnormally short venous refilling time (less than 18 seconds) developed in 21% of the extremities, which had a normal venous refilling time earlier in the same day. Lower extremity symptoms of ache, pain, or swelling were reported more frequently in extremities that developed an abnormal venous refilling time. There was a trend toward a greater change in venous refilling time during the day in symptomatic lower extremities than in asymptomatic limbs (p = 0.07).

The 1-month prognosis of 91 limbs with a pulseless foot in 49 patients was determined and related to elements of the physical examination, including Doppler ultrasonography. The risk factors that could predict loss of limb and death in this group of patients were determined. Gangrene and atrophy coupled with absent ultrasound signals predicted a 75% risk of loss of limb; this occurred despite attempted surgical intervention. Absence of Doppler signals in both ankle arteries was the strongest risk factor for predicting death. This is probably because ultrasound signals are absent only when arterial disease is far advanced. We conclude that Doppler ultrasound examination of the pulseless foot yields useful prognostic information relative to the fate of the limb and the patient who possesses such a limb.