Modeling a Predictive Energy Equation Specific for Maintenance Hemodialysis

Background: Hypermetabolism is theorized in patients diagnosed with chronic kidney disease who are receiving maintenance hemodialysis (MHD). We aimed to distinguish key disease‐specific determinants of resting energy expenditure to create a predictive energy equation that more precisely establishes energy needs with the intent of preventing protein‐energy wasting. Materials and Methods: For this 3‐year multisite cross‐sectional study (N = 116), eligible participants were diagnosed with chronic kidney disease and were receiving MHD for at least 3 months. Predictors for the model included weight, sex, age, C‐reactive protein (CRP), glycosylated hemoglobin, and serum creatinine. The outcome variable was measured resting energy expenditure (mREE). Regression modeling was used to generate predictive formulas and Bland‐Altman analyses to evaluate accuracy. Results: The majority were male (60.3%), black (81.0%), and non‐Hispanic (76.7%), and 23% were ≥65 years old. After screening for multicollinearity, the best predictive model of mREE (R² = 0.67) included weight, age, sex, and CRP. Two alternative models with acceptable predictability (R² = 0.66) were derived with glycosylated hemoglobin or serum creatinine. Based on Bland‐Altman analyses, the maintenance hemodialysis equation that included CRP had the best precision, with the highest proportion of participants’ predicted energy expenditure classified as accurate (61.2%) and with the lowest number of individuals with underestimation or overestimation. Conclusions: This study confirms disease‐specific factors as key determinants of mREE in patients on MHD and provides a preliminary predictive energy equation. Further prospective research is necessary to test the reliability and validity of this equation across diverse populations of patients who are receiving MHD.     

In vivo magnetic resonance spectroscopy of transgenic mouse models with altered high-energy phosphoryl transfer metabolism

Studies of transgenic mice provide powerful means to investigate the in vivo biological significance of gene products. Mice with an under- or overexpression of enzymes involved in high-energy phosphoryl transfer (approximately P) are particulary attractive for in vivo MR spectroscopy studies as the substrates of these enzymes are metabolites that are visible in MR spectra. This review provides a brief overview of the strategies used for generation and study of genetically altered mice and introduces the reader to some practical aspects of in vivo MRS studies on mice. The major part of the paper reviews results of in vivo MRS studies on transgenic mice with alterations in the expression of enzymes involved in approximately P metabolism, such as creatine kinase, adenylate kinase and guanidinoacetate methyl transferase. The particular metabolic consequences of these enzyme deficiencies in skeletal muscle, brain, heart and liver are addressed. Additionally, the use of approximately P systems as markers of gene expression by MRS, such as after viral transduction of genes, is described. Finally, a compilation of tissue levels of metabolites in skeletal muscle, heart and brain of wild-type and transgenic mice, as determined by in vivo MRS, is given. During the last decade, transgenic MRS studies have contributed significantly to our understanding of the physiological role of phosphotransfer enzymes, and to the view that these enzymes together build a much larger metabolic energy network that is highly versatile and can dynamically adapt to intrinsic genotoxic and extrinsic physiological challenges.     

Physical activity patterns of kindergarten children in comparison to teenagers and young adults

BACKGROUND: Due to the increasing occurrence of obesity and low physical activity (PA) reported in school children there is a need to investigate PA patterns of preschool children. Our aim was to identify the PA of preschool children in comparison to the PA of teenagers and young adults. METHODS: PA of 104 Czech preschool children (aged 5-7 years), 1174 teenagers (aged 12-17 years) and 787 young adults (aged 18-24 years) was determined using Caltrac accelerometery. PA was evaluated on the basis of activity energy expenditure (AEE--kcal kg(-1) day(-1)). Subjects were monitored over 7 days to include a weekend. RESULTS: The AEE in preschool children was significantly higher in comparison to all age groups of teenagers and young adults during both weekdays and at the weekend (P<0.0001). On weekdays during leisure time, preschoolers were considerably more physically active than all categories of teenagers and young adults (P<0.001). Preschoolers show similarities in PA level between weekdays and weekends, unlike the older age groups. CONCLUSION: It seems to appear that organized daily PA (2x20 min of exercising on carpet, 50-70 min of walking outdoors) in preschool children along with enough space for spontaneous PA establishes prerequisites for their further healthy development.     

A novel group contribution method in the development of a QSAR for predicting the toxicity (Vibrio fischeri EC50) of ionic liquids

To achieve better management of processes and products, information on toxicity, safety, and risk assessment of chemicals is required. Ionic liquids are compounds of high interest for industry because of their attractive properties as solvents, but the water solubility of these compounds may lead to aquatic pollution and related risks. Experimental toxicity evaluation (Vibrio fischeri EC(50)) is a measurement of aquatic toxicity but there are theoretically over 1 million ionic liquids, which makes it necessary to estimate their properties by means of quantitative structure-activity relationships (QSARs). A database of Vibrio fischeri EC(50) was assembled to develop a novel group contribution method for estimating the EC(50) of ionic liquids. From the results the group contributions of anion, cation and alkyl substitutions has been calculated. The group contribution method allows an estimation of different combinations of groups in the toxicity (EC(50)) of ionic liquids.     

A pilot study to compare the use of prototypes of multipositional paediatric walking sticks and tripods with conventional sticks and tripods by children with cerebral palsy

BACKGROUND: The researchers (B.H. and B.T.) designed prototypes of a walking stick and a tripod termed Multipositional Paediatric Walking Aids for children with cerebral palsy (CP). The design won the 'Jenx Award for Innovation in Paediatric Physiotherapy'. The object of this study was to ascertain whether the prototypes had any benefit over conventional designs in children with CP. METHODS: A small case series within-subject comparison design was used. There were four periods, AABA, each 4 weeks in length. Prototypes were used during period B. Eight children with CP between 4 and 11 years were recruited, four used sticks and four used tripods. Following an orthopaedic assessment, each child had assessments at the commencement of the study and every 4 weeks thereafter: (1) Energy used while walking using Physiological Cost Index (PCI). (2) Motor abilities using (a) Gross Motor Function Measure (GMFM-88) and (b) Gross Motor Performance Measure (GMPM). (3) Hand/forearm position recorded on a visual analogue. (4) Parent/child questionnaire. RESULTS: Physiological Cost Index improved overall when the prototypes were used suggesting the amount of energy used when walking with the prototypes was less than with conventional sticks/tripods. GMFM-88 and GMPM results improved for some but not all children. Results for PCI, GMFM and GMPM were not statistically significant. The hand/forearm position of stick users consistently improved at assessment 4. Questionnaire results indicated that stick users preferred the prototypes. CONCLUSION: Multipositional sticks/tripods may have benefits over conventional sticks/tripods. Children using sticks rather than tripods preferred the prototypes. The study demonstrates the need to undertake scientifically controlled trials before marketing new equipment.     

Thermal Energy in Arthroscopy, What''s New in 2003?

Since Hippocrates, who stabilized an unstable shoulder with an heated iron rod in the axilla, up to now, physicians have still tried to use heat in different kinds of treatments.

Most important heat procedures consist in control bleeding and sterilizing of wounds.

Laser and Radiofrequencies devices are available in arthroscopic surgery since 1990. They allow haemostasis, but also they can ablate tissue and shrink joint capsule. This technology is considered very useful or, at the opposite denied by surgeons.

We are experienced in both devices. After a general review of the literature, we point out the main facts and updates among these papers.     

Density-dependent Energy Loss of Protons in Pb and Be Targets and Percent Mass-Stopping Power from Bethe-Bloch Formula and Bichsel-Sternheimer Data Within 1–12 MeV Energy Range: A Comparative Study Based on Bland-Altman Analysis

Background

This comparative study calculated Bethe-Bloch results with Bichsel-Sternheimer values, employing the Bland-Altman analysis within 95% limit of agreement for the first time. The Bethe-Bloch formula was employed for the physical realization of the density-dependent energy loss of protons in lead (²⁰⁸Pb) and beryllium (⁹Be) targets in the energy range 1–12 MeV.