Association of infra-patellar fat pad size with age and body weight in children and adolescents.

BACKGROUND: The infra-patellar fat pad (IPFP) represents a potential mediator between obesity, low grade inflammation, and knee osteoarthritis via endocrine pathways. Yet, not only in adults, but also in childhood obesity negatively impacts knee structures. OBJECTIVE: The current study therefore investigated the sex-specific growth of the IPFP with age and body weight in healthy children and adolescents. MATERIALS AND METHODS: Thirty young healthy subjects (60% girls; age 4-17 years, body weight 14-90 kg in girls and 29-105 kg in boys; BMI 12.2-32.4 kg/m2) without magnetic resonance imaging (MRI) knee pathology were studied. The IPFP volume was determined from sagittal T-1 weighted and proton-density spectral attenuated inversion recovery MRIs. The primary analysis focused on the sex-specific IPFP volume/body weight ratio as dependent, and age as independent variable, using linear regression models. A secondary analytic focus was the slope of the age-dependence of IPFP volume, without normalization to body weight. RESULTS: There was no statistically significant association of the IPFP volume/body weight ratio with age in girls (p = 0.57) or boys (p = 0.31), the R2 of ranging from -0.32 to 0.14. The ratio was greater in boys (0.54 ±â€¯0.10 cm3/kg) than in girls (0.45 ±â€¯0.07 cm3/kg) (p < 0.01). The IPFP volume increased by approx. 2 cm3 per annum in both girls and boys, without any indication of a non-linear relationship. CONCLUSION: Our findings reveal that the ratio of the IPFP volume and body weight remains constant between age 4 and 17 in both normal weight girls and boys, and that the IPFP volume increases linearly with age throughout this period.

Appraisal of guidelines developed by the World Health Organization.

OBJECTIVE: To appraise the quality of guidelines developed by the World Health Organization (WHO) that were approved by its Guidelines Review Committee (GRC) and identify strengths and weaknesses in the guideline development process. STUDY DESIGN: Cross-sectional. METHODS: Three individuals independently assessed GRC-approved WHO guidelines using the Appraisal of Guidelines for Research and Evaluation II instrument (AGREE II). Scores were standardized across domains and overall quality was determined through consensus. RESULTS: 124 guidelines met inclusion criteria and were assessed. 58 guidelines were recommended for use, 58 were recommended with modifications and eight were not recommended. The highest scoring domains across guidelines were scope and purpose, and clarity of presentation. The recommended guidelines had higher rigor of development and applicability domain scores in comparison to other guidelines. 77% of the guidelines referenced an underlying evidence review and 49% used GRADE to assess the body of evidence or the strength of the recommendation. The domains in need of improvement included stakeholder engagement, editorial independence, and applicability. Guidelines not recommended for use were generally insufficient in their rigor of development. CONCLUSIONS: WHO guidelines need further improvement, most importantly in the rigor of their development (i.e., use of evidence reviews). Other areas for improvement include increased stakeholder engagement, a more explicit process for recommendation formulation and disclosure of interests, discussion of the facilitators, barriers, resource implications, and criteria for monitoring the outcomes of guideline implementation. WHO guidelines can improve through increased transparency, adherence to the WHO Handbook for Guideline Development, and better oversight by the GRC.

System of automated gas-exchange analysis for the investigation of metabolic processes.

Conventional gas-exchange instruments are confined to the measurement of O(2) consumption (VO(2)) and CO(2) production (VCO(2)) and are subject to a variety of errors. This handicaps the performance of these devices at inspired O(2) fraction (FI(O(2))) > 0.40 and limits their applicability to indirect calorimetry only. We describe a device based on the automation of the Douglas bag technique that is capable of making continuous gas-exchange measurements of multiple species over a broad range of experimental conditions. This system is validated by using a quantitative methanol-burning lung model modified to provide reproducible (13)CO(2) production. The average error for VO(2) and VCO(2) over the FI(O(2)) range of 0.21-0.8. is 2.4 and 0.8%, respectively. The instrument is capable of determining the differential atom% volume of known references of (13)CO(2) to within 3.4%. This device reduces the sources of error that thwart other instruments at FI(O(2)) > 0. 40 and demonstrates the capacity to explore other expressions of metabolic activity in exhaled gases related to the excretion of (13)CO(2).

Quantitative methanol-burning lung model for validating gas-exchange measurements over wide ranges of FIO2.

The methanol-burning lung model has been used as a technique for generating a predictable ratio of carbon dioxide production (VCO2) to oxygen consumption (VO2) or respiratory quotient (RQ). Although an accurate RQ can be generated, quantitatively predictable and adjustable VO2 and VCO2 cannot be generated. We describe a new burner device in which the combustion rate of methanol is always equal to the infusion rate of fuel over an extended range of O2 concentrations. This permits the assembly of a methanol-burning lung model that is usable with O2 concentrations up to 100% and provides continuously adjustable and quantitative VO2 (69-1,525 ml/min) and VCO2 (46-1,016 ml/min) at a RQ of 0.667.