Urinary excretion and efflux from the leg of 3-methylhistidine before and after major surgical operation

Changes in the effluxes from the leg of 3-methylhistidine and tyrosine were studied in relation to alterations in the 24-hour excretion of 3-methylhistidine and total nitrogen in 11 patients before and after undergoing major surgical operation. On the first day after operation, efflux of 3-methylhistidine from the leg was significantly decreased by 40% compared to preoperative values. In contrast, tyrosine efflux was doubled at the same time as a transient 20% increase in oxygen uptake of the leg and a marked increase in catecholamine excretion were observed. These changes coincided with a 40% elevation in the excretion of both 3-methylhistidine and nitrogen. Leg metabolism returned to the preoperative pattern within a week. These results suggest that the loss of amino acids from the lean tissues of the leg is the result of a fall in protein synthesis accompanied by an adaptive fall in protein breakdown. Although the increase in nitrogen excretion in response to major surgical trauma reflects the negative amino acid balance of skeletal muscle, the changes in urinary 3-methylhistidine do not correlate with changes in efflux of 3-methylhistidine from the leg. These results suggest that the use of 3-methylhistidine excretion as a specific index of skeletal muscle protein breakdown in postoperative patients may be invalid. Tissues other than skeletal muscle appear to make a substantial contribution to the 3-methylhistidine excretion postoperatively.     

Internet Gaming Disorder: Compensating as a Draenei in World of Warcraft

The diagnosis of Gaming Disorder (GD) has been recently proposed in the beta draft of the 11th revision of the International Classification of Diseases (ICD-11) by the World Health Organization (WHO). This follows the inclusion of Internet Gaming Disorder (IGD), as a condition requiring additional research in the Diagnostic Statistical Manual for Mental Disorders (DSM-5), issued by the American Psychiatric Association (APA). Further research has been recommended to enhance understanding of excessive gaming, especially in the context of user-avatar (in-game figure representing the gamer) relationships. The association between selecting the Draenei race, compensation of real-life deficits through gaming, and the gamer’s gender were investigated as IGD risk factors among players of the online game, World of Warcraft (WoW). A normative online sample of WoW gamers (N = 404 M_age = 25.56; 13–75; males = 299; 74%) completed the Internet Gaming Disorder Scale–Short-Form (IGDS9-SF) and the compensation subscale of the User-Avatar Questionnaire. Regression, mediation, and moderated mediation analyses were conducted. Overall, players with higher levels of compensation exhibited greater levels of IGD symptoms. Interestingly, choosing the Draenei race was associated with increased compensatory behavior, which in turn linked to higher IGD risk. These associations were mildly stronger among females. Findings suggest that virtual demographics, such as the Draenei race, and their interplay with compensatory behaviors should be carefully considered when creating prevention and intervention policies targeting excessive gaming, especially when it involves the use of avatars.

     

The Necessity-Concerns Framework: a Multidimensional Theory Benefits from Multidimensional Analysis

Background

Patients’ medication-related concerns and necessity-beliefs predict adherence. Evaluation of the potentially complex interplay of these two dimensions has been limited because of methods that reduce them to a single dimension (difference scores).

Purpose

We use polynomial regression to assess the multidimensional effect of stroke-event survivors’ medication-related concerns and necessity beliefs on their adherence to stroke-prevention medication.

Methods

Survivors (n?=?600) rated their concerns, necessity beliefs, and adherence to medication. Confirmatory and exploratory polynomial regression determined the best-fitting multidimensional model.

Results

As posited by the necessity-concerns framework (NCF), the greatest and lowest adherence was reported by those necessity weak concerns and strong concerns/weak Necessity-Beliefs, respectively. However, as could not be assessed using a difference-score model, patients with ambivalent beliefs were less adherent than those exhibiting indifference.

Conclusions

Polynomial regression allows for assessment of the multidimensional nature of the NCF. Clinicians/Researchers should be aware that concerns and necessity dimensions are not polar opposites.     

Use of naloxone during cardiac arrest and CPR: potential adjunct for postcountershock electrical-mechanical dissociation

Naloxone has been shown to increase arterial pressure in hemorrhagic and septic shock. To determine if naloxone has salutary effects during cardiac arrest with conventional closed-chest cardiopulmonary resuscitation (CPR), ten dogs were studied during 20 minutes of ventricular fibrillation (VF) and CPR and during a 30-minute postcountershock period. Central aortic (Ao) and right atrial (RA) systolic and end-diastolic (EDP) pressures, instantaneous Ao-RA pressure difference (coronary perfusion pressure), and electromagnetic Ao flow were measured. Ao and RA samples were analyzed during a control period and at five-minute intervals during CPR for PO2, PCO2, and pH. During VF, a piston-cylinder device was used to perform anteroposterior sternal depressions and positive pressure ventilations (100% O2) at standard rates and ratios. After 15 minutes of CPR, animals were randomized and given either naloxone (5 mg/kg) or epinephrine (1 mg). Defibrillation was attempted five minutes later using 1 J/kg and then, if necessary, 2, 4, 8, 12, and 16 J/kg until VF was terminated or the maximum energy dose was reached. If VF persisted or if countershock resulted in asystole or a nonperfusing rhythm (electrical-mechanical dissociation [EMD]), the alternate drug (naloxone or epinephrine) was then given. Measured systolic pressures, coronary perfusion pressures, aortic flow, and blood gases were not significantly different during the control period or at five, ten, and 15 minutes of VF and CPR between animal groups prior to drug administration. When compared to hemodynamic values measured at 15 minutes, naloxone had no significant effect on pressures or aortic flow measured five minutes after administration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Energy expenditure and body composition in growth hormone deficient adults on exogenous growth hormone

OBJECTIVES We assessed whether the obesity observed in growth hormone deficient adults is maintained by a reduction in energy expenditure. We studied the effects of exogenous growth hormone on energy expenditure and body composition. DESIGN We performed an open study with growth hormone administered at 0 5 units per kilogram ideal body weight per week for 3 months. PATIENTS Seven growth hormone deficient adults were studied. Thirty-eight healthy volunteers had their resting metabolic rate measured, with seven of them proceeding to have their total energy expenditure assessed. MEASUREMENTS Total energy expenditure was measured by the doubly labelled water method (D₂0¹⁸), resting metabolic rate by ventilated hood indirect calorimetry, and fat free mass from the dilution volume of oxygen-18. Body composition and components of energy expenditure were assessed before, at 2 weeks and at the end of the 3-month treatment period on exogenous growth hormone. RESULTS Growth hormone deficient adults did not have a low total energy expenditure compared to healthy controls (13 12 vs 12 75 MJ/24 h) with only one patient expending less than 10 MJ/24 h. None had a resting metabolic rate lower than the 95% confidence limits of normality. The amount of energy expended on physical activity and thermogenesis was significant (6 54 MJ/24 h) and was similar to healthy controls (6 47 MJ/24 h). Resting metabolic rate increased by 15 9% after 14 days on exogenous growth hormone and was elevated 12-1% after 3 months treatment but the ratio to fat-free mass remained unaltered. Total energy expenditure increased by 13 4% after 14 days therapy. Fat-free mass increased significantly after 3 months treatment by (mean) 4 5 kg with no change in fat mass and no loss in body weight. CONCLUSIONS Obesity maintenance in growth hormone deficient adults is not a consequence of reduced total energy expenditure or a reduced exercise energy output. There was also no evidence for an energy sparing mechanism. Energy expenditure was increased by exogenous growth hormone but was not associated with a loss in fat mass or body weight suggesting the need for dietetic advice for those already obese at the outset of therapy.     

Isolation of aminoacyl-tRNA and its labeling with stable-isotope tracers: Use in studies of human tissue protein synthesis.

We isolated aminoacyl-tRNA (60-70% yield) from human and rat tissues and measured, by GC/MS, its labeling in vivo by [15N]- and [13C]leucine. Tracer dilution artifacts seemed unlikely since, after infusion of L-[1-13C,15N]leucine into rats, (i) muscle leucyl-tRNA labeling exceeded tissue free leucine labeling, (ii) values were largely unaffected by storing over 5 min at 22 degrees C, and (iii) L-[2,4,5-methyl-13C]leucine was not incorporated into leucyl-tRNA during homogenization. Leucyl-tRNA labeling in liver and muscle suggested charging from extra- and intracellular pools: e.g., after infusing L-[1-13C,15N]leucine, rat muscle tissue free leucine 13C labeling (8.97 +/- 0.30 atom % excess) exceeded that by 15N (3.37 +/- 0.33 atom % excess), and both were significantly lower (P less than 0.02) than venous plasma (13C, 12.1 +/- 1.8; 15N, 5.54 +/- 0.6 atom % excess) indicating tracer dilution by transamination and by proteolysis; however, leucyl-tRNA labeling by either isotope (13C, 10.26 +/- 0.50; 15N, 4.72 +/- 0.72 atom % excess) was significantly above mixed tissue free leucine (P less than 0.05). Labeling of leucyl-tRNA in human erector spinae muscle (obtained after preoperative L-[1-13C]leucine infusion) was, at 4.98 +/- 0.43 atom % excess, lower (27%) than venous plasma leucine (P less than 0.05) and intermediate between muscle free leucine (9% lower; P less than 0.01) and venous alpha-ketoisocaproate (11% higher; P less than 0.02). Human placental leucyl-tRNA labeling (after predelivery tracer infusion) was 37% lower (P less than 0.05) than maternal uterine vein labeling but not significantly different from placental free leucine or umbilical arterial leucine.     

Limited agreement between written and video asthma symptom questionnaires

The prevalence of asthma remains difficult to determine with precision with no absolute or "gold" standard for diagnosis. A recently developed video questionnaire for epidemiological studies with less reliance on understanding written questions provides another tool for determining prevalence and severity of asthma. This report from the International Study of Asthma and Allergies in Childhood (ISAAC) examines the agreement between the ISAAC video questionnaires on respiratory symptoms and reported asthma. Between December 1993 and April 1995, 4952 children aged 13-14 years in two Canadian communities completed sequentially the ISAAC written and video questionnaires at school. The agreement between responses to the two questionnaires for reported wheeze ever, current wheeze, wheeze on exercise, and nocturnal wheeze (the latter three questions relating to symptoms in the last 12 months), and to any combination of the latter three questions was examined in the full sample and in those reporting diagnosed asthma, using concordance and kappa coefficients as measures of agreement. The prevalences of wheeze ever, current wheeze, wheeze on exercise, and nocturnal wheeze were significantly lower based on responses to the video questionnaire compared with the written questionnaire in both regions in the full sample and in those labeled as having asthma. Although concordance between video and written questionnaires always exceeded 60% and often exceeded 70% for related questions, agreement measured by the kappa statistic for each question was only fair to moderate (kappa = 0.22-0.51). We conclude that the video questionnaire yields lower reported prevalence rates for asthma symptoms, and that there is limited agreement between responses to the two questionnaires that is not explained by issues of language, culture, or literacy.