4～6月龄婴儿能量需要量研究

用双标记水法对广东２３名４月龄和２１名６月龄健康婴儿的总能量消耗进行为期８天的测量，用称重法测定婴儿２４小时母乳和食物摄入量，计算婴儿的能量摄入量，通过测定婴儿的体重变化估计生长的能量贮留，以了解婴儿的能量摄入是否满足其基础代谢、活动和生长等的需要。结果：母乳组和人工喂养组４月龄婴儿的能量摄入分别为３３０±６０和４０２±４６ｋＪ／（ｋｇ·ｄ），能量贮留分别为４９±１９和４９±１９ｋＪ／（ｋｇ·ｄ），能量消耗分别为２６８±７９和３２６±７９ｋＪ／（ｋｇ·ｄ）。母乳组和人工喂养组６月龄婴儿的能量摄入分别为３４７±７１和３８９±８８ｋＪ／（ｋｇ·ｄ），能量贮留分别为１８±１１和２９±１１ｋＪ／（ｋｇ·ｄ），能量消耗分别为３２２±９６和３４３±１２１ｋＪ／（ｋｇ·ｄ）。４～６月龄婴儿的能量需要量估计为３７３ｋＪ／（ｋｇ·ｄ）。     

肝硬变大鼠Hassab手术前后肝脏能量代谢改变的意义

测定正常及肝硬变大鼠Ｈａｓｓａｂ手术前后不同时相肝脏组织腺苷酸和腺苷环－磷酸容量，结果发现术前硬变肝组织三磷酸腺苷含量和能荷水平明显降低，术后ＡＴＰ、总腺苷酸含量和ＥＣ进一步减少，ｃＡＭＰ含量亦甚低下。实验表明：硬变肝细胞内物质代谢及其调节机制严重紊乱，应激状态下较易发生肝功能衰竭。     

New experimental setup for studying strictly noninvasively skeletal muscle function in rat using 1H-magnetic resonance (MR) imaging and 31P-MR spectroscopy.

Traditional setups for in situ MR investigation of skeletal muscle function in animals use invasive systems for muscle stimulation and force measurement. These systems require surgical preparation and therefore exclude repetitive investigations on the same animal. This article describes a new experimental setup allowing strictly noninvasive MR investigations of muscle function in contracting rat gastrocnemius muscle using 1H-MR imaging and 31P-MR spectroscopy. The novelty of this setup is the integration of two noninvasive systems allowing muscle contraction by transcutaneous stimulation and force measurement with a dedicated ergometer. Muscle function was investigated in 20 rats (275-300 g) through a fatiguing stimulation protocol, either with this noninvasive setup (n = 10) or with a traditional MR setup (n = 10). T2-weighted images demonstrated that transcutaneous stimulation activated mainly the gastrocnemius muscle. Moreover, the changes in force development and in energy metabolism obtained with the noninvasive setup were qualitatively and quantitatively similar to those obtained with the traditional setup. This noninvasive setup is thus suitable for investigating skeletal muscle function in situ. It offers the possibility to repeat investigations in the same animal, avoiding individual variability and enabling longitudinal follow-up studies. This opens up new perspectives in various research areas including pharmaceutical research.     

Cardiac monitoring of human subjects exposed to the taser

The Taser (TASER International, Scottsdale, AZ) is a high-voltage, low-amperage device used by many law enforcement agencies. Our objective in this study was to evaluate for rhythm changes utilizing cardiac monitoring during deployment of the Taser on volunteers. A prospective, observational study evaluated law enforcement personnel who had continuous electrocardiographic monitoring immediately before, during, and after having a voluntary exposure to the Taser X-26. Changes in cardiac rate, rhythm, ectopy, morphology, and conduction intervals were measured. A total of 105 subjects were evaluated. The mean shock duration was 3.0 s (range 0.9-5 s). Mean heart rate increased 15 beats/min (95% CI 12.6-18.3), from 122 beats/min before shock to 137 beats/min immediately after shock. One subject had a single premature ventricular contraction both before and after the shock, but no other subject developed ectopy or dysrhythmia. Poor inter-rater agreement prevented determination of the overall effect of shock on conduction intervals. However, several interpretable tracings demonstrated change in QT duration-either shortening or prolongation after shock. Human subjects exposed to a brief shock from the Taser developed significant increases in heart rate, but there were no cardiac dysrhythmias or morphologic changes. Alterations in the QT interval were observed in some subjects but their true incidence and clinical significance are unknown.     

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.     

Public health expenditure and spatial interactions in a decentralized national health system

One of the limitations of cross-country health expenditure analysis refers to the fact that the financing, the internal organization and political restraints of health care decision-making are country-specific and heterogeneous. Yet, a way through is to examine the influence of such effects in those countries that have undertaken decentralization processes. In such a setting, it is possible to examine potential expenditure spillovers across the geography of a country as well as the influence of the political ideology of regional incumbents and institutional factors on public health expenditure. This paper examines the determinants of public health expenditure within Spanish region-states (Autonomous Communities, ACs), most of them subject to similar financing structures although exhibiting significant heterogeneity as a result of the increasing decentralization, region-specific political factors along with different use of health care inputs, economic dimension and spatial interactions.