Validity and Reliability of Tools to Measure Muscle Mass,Strength, and Physical Performance in Community-Dwelling Older People: A Systematic Review

BackgroundThis study critically appraises the measurement properties of tools to measure muscle mass, strength, and physical performance in community-dwelling older people. This can support the selection of a valid and reliable set of tools that is feasible for future screening and identification of sarcopenia.MethodsThe databases PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Cochrane were systematically searched (January 11, 2012). Studies were included if they investigated the measurement properties or feasibility, or both, of tools to measure muscle mass, strength, and physical performance in community-dwelling older people aged ≥60 years. The consensus-based standards for the selection of health status measurement instruments (COSMIN) checklist was used for quality appraisal of the studies.ResultsSixty-two publications were deemed eligible, including tools for muscle mass (n = 16), muscle strength (n = 15), and physical performance (n = 31). Magnetic resonance imaging, computed tomography, and a 4-compartment model were used as gold standards for muscle mass assessment. Other frequently used measures of muscle mass are dual-energy x-ray and the bioelectrical impedance (BIA); however, reliability data of the BIA are lacking. Handheld dynamometry and gait speed or a short physical performance battery provide a valid and reliable measurement of muscle strength and physical performance, respectively.ConclusionsIt can be concluded that several tools are available for valid and reliable measurements of muscle mass, strength, and performance in clinical settings. For a home-setting BIA, handheld dynamometry and gait speed or a short physical performance battery are the most valid, reliable, and feasible. The combination of selected instruments and its use for the screening and identification of sarcopenia in community-dwelling older people need further evaluation.     

Risk of cardiovascular thrombotic events after surgical castration versus gonadotropin-releasing hormone agonists in Chinese men with prostate cancer

We investigated the cardiovascular thrombotic risk after surgical castration (SC) versus gonadotropin-releasing hormone agonists (GnRHa) in Chinese men with prostate cancer. All Chinese prostate cancer patients who were treated with SC or GnRHa from year 2000 to 2009 were reviewed and compared. The primary outcome was any new-onset of cardiovascular thrombotic events after SC or GnRHa, which was defined as any event of acute myocardial infarction or ischemic stroke. The risk of new-onset cardiovascular thrombotic event was compared between the SC group and the GnRHa group using Kaplan–Meier method. Multivariate Cox regression analysis was performed to adjust for other potential confounding factors. A total of 684 Chinese patients was included in our study, including 387 patients in the SC group and 297 patients in the GnRHa group. The mean age in the SC group (75.3 ± 7.5 years) was significantly higher than the GnRHa group (71.8 ± 8.3 years) (P < 0.001). There was increased risk of new cardiovascular thrombotic events in the SC group when compared to the GnRHa group upon Kaplan–Meier analysis (P = 0.014). Upon multivariate Cox regression analysis, age (hazard ratio [HR] 1.072, 95% confidence interval [CI] 1.04–1.11, P< 0.001), hyperlipidemia (HR 2.455, 95% CI 1.53–3.93, P< 0.001), and SC (HR 1.648, 95% CI 1.05–2.59, P = 0.031) were significant risk factors of cardiovascular thrombotic events. In conclusion, SC was associated with increased risk of cardiovascular thrombotic events when compared to GnRHa. This is an important aspect to consider while deciding on the method of androgen deprivation therapy, especially in elderly men with known history of hyperlipidemia.     

Rp－HPLC法测定血清中的抗生育甾体药物利洛司酮

以ＲＵ４８６为内标，建立了血清样品中新型抗孕激素甾体药物利洛司酮（ｌｉｌｏｐｒｉｓｔｏｎｅ）的反相高效液相色谱法。色谱分析条件为μＢｏｎｄａｐａｋＣ１８柱１０μｍ，３００ｍｍ×３．９ｍｍＩＤ；流动相为甲醇－二氯甲烷－１０ｍｍｏｌ·Ｌ－１磷酸盐缓冲液（ｐＨ４．０）（６７：５：２８ｖ／ｖ）；紫外检测波长为３０２ｎｍ。利洛司酮的检测限为１ｎｇ（Ｓ／Ｎ≥４：１）。血清样品经二次液一液超声振荡萃取后，得到了较好的净化。血清样品中利洛司酮的方法回收率为１０３．３％，日内精密度及日间精密度平均ＲＳＤ为３．５１％及２．９２％。在浓度为１０～１０００ｎｇ·ｍｌ－１血清范围内呈线性关系。     

An analysis of fetal hemoglobin variation in sickle cell disease: the relative contributions of the X-linked factor, beta-globin haplotypes, alpha-globin gene number, gender, and age

Five factors have been shown to influence the 20-fold variation of fetal hemoglobin (Hb F) levels in sickle cell anemia (SS): age, sex, the alpha-globin gene number, beta-globin haplotypes, and an X-linked locus that regulates the production of Hb F-containing erythrocytes (F cells), ie, the F-cell production (FCP) locus. To determine the relative importance of these factors, we studied 257 Jamaican SS subjects from a Cohort group identified by newborn screening and from a Sib Pair study. Linear regression analyses showed that each variable, when analyzed alone, had a significant association with Hb F levels (P < .05). Multiple regression analysis, including all variables, showed that the FCP locus is the strongest predictor, accounting for 40% of Hb F variation. beta-Globin haplotypes, alpha-globin genes, and age accounted for less than 10% of the variation. The association between the beta-globin haplotypes and Hb F levels becomes apparent if the influence of the FCP locus is removed by analyzing only individuals with the same FCP phenotype. Thus, the FCP locus is the most important factor identified to date in determining Hb F levels. The variation within each FCP phenotype is modulated by factors associated with the three common beta-globin haplotypes and other as yet unidentified factor(s).     

Measuring whole-body actin/myosin protein breakdown in mice using a primed constant stable isotope-infusion protocol

To measure actin/myosin protein breakdown, the 24 h excretion of N (tau)-methylhistidine (3MH) is used. However, in mice, this method is invalid. Therefore we have developed a liquid chromatography-MS technique to measure the tracer/tracee ratio and concentration of 3MH in plasma, enabling an in vivo primed constant infusion protocol with a deuterated stable isotope of 3MH. We tested this model by giving a primed constant infusion of L-[3-methyl-(2)H(3)]histidine, L-[phenyl-(2)H(5)]phenylalanine and L-[phenyl-(2)H(2)]tyrosine to three anaesthetized experimental groups: mice receiving saline intraperitoneally (i.p.) (CON), mice receiving saline i.p. and starved for 9 h (STA), and mice receiving lipopolysaccharide i.p. and starved for 9 h (STA+LPS). The contribution of myofibrillar to total protein breakdown was significantly lower in the STA group than the CON group (30+/-4% and 54+/-14% respectively; P <0.05), and was significantly higher in the STA+LPS group than the STA group (52+/-7% and 30+/-4% respectively; P <0.05). Whole-body myofibrillar protein breakdown, total protein breakdown, protein synthesis and net protein breakdown were not different between the groups. We conclude that this in vivo primed constant stable isotope-infusion protocol can give valuable information about the role of actin/myosin protein breakdown in mice.