Age‐related plasma reference ranges for two heparin‐binding proteins – vitronectin and platelet factor 4

This study was conducted to establish age‐related reference ranges for two heparin‐binding proteins – vitronectin and platelet factor 4 (PF4) – and to determine if the quantitative values of these proteins may contribute to the reported age‐dependent effect of unfractionated heparin (UFH). Plasma samples were obtained from healthy children aged between 1 month and 16 years and from healthy adult volunteers. Two commercial kits were used to measure plasma vitronectin and PF4 levels. Results were reported as mean and boundaries including 95% of the population. Plasma vitronectin levels for children aged 1–5 years were significantly higher compared with adults. Plasma PF4 levels for infants <1 year of age were significantly lower compared with adults. The differences between reference values for both proteins in all other age‐groups were not statistically significant. This study for the first time has established age‐related reference ranges for vitronectin and PF4. In establishing these ranges, the quantitative values of these proteins do not appear to be the major contributory cause for the age‐dependent variation in UFH effect. Future studies are required to evaluate the possible impact of age‐dependent differences in binding between heparin‐binding proteins and UFH.     

Standardization of thromboelastography: a report from the TEG‐ROTEM working group

Summary. Laboratory evaluation of bleeding disorders has been performed with the standard clotting assays such as the PT and PTT for several decades. Our improved understanding of the process of blood coagulation has now revealed the important role played by the cellular elements such as platelets, monocytes and red blood cells. The need for a test that can assess clotting in a more ‘global’ manner, beyond the initiation of clot formation, has led to greater interest in assays such as thrombin generation and thromboelastography. Even though there are several publications using thromboelastography it remains a research tool as the methodology is not standardized. In an attempt to show reproducibility and consistency using thromboelastography, a group of investigators from different countries joined hands to form the TEG‐ROTEM Working Group. Two studies were performed using PRP and FVIII deficient plasma and an intrinsic pathway activator. This article summarizes the results of the first international effort at standardization of thromboelastography. Both of the instruments using this technology (TEG^® and ROTEM^®) were used. Nine laboratories from countries around the globe participated in this effort. The results showed a significant inter‐laboratory variance with CV’s greater than 10%. Although these results were not satisfactory, this has been the first effort to standardize this methodology and significant work remains to be done to improve reliability and reproducibility. These studies were performed on PRP and the results may be more reliable when preformed on whole blood samples. We believe that it is important to continue this work so that we may investigate the usefulness and potential applications of thromboelastography in the evaluation of bleeding and thrombosis.     

健康傣族人CD3+ CD4+和CD8+ T淋巴细胞绝对数正常值调查

目的了解德宏州健康傣族人群外周静脉血CD3 、CD4 、CD8 T淋巴细胞绝对数和CD4 /CD8 比值的正常值范围。方法应用流式细胞仪(FACSCount)检测253例健康傣族人的CD3 、CD4 、CD8 T淋巴细胞绝对数和CD4 /CD8 比值,并观察以上数值在性别和年龄上的差异。结果CD3 、CD4 、CD8 和CD4 /CD8 的正常值参考范围分别为(1 543±443)个/μl(、849±261)个/μl(、567±225)个/μl和1.63±0.55。CD3 、CD4 在性别和年龄组别间的差异均无统计学意义,而CD8 和CD4 /CD8 在年龄组别间的差异有统计学意义。结论初步建立了健康傣族人群CD3 、CD4 、CD8 和CD4 /CD8 的正常值参考范围,对于指导德宏州艾滋病的诊断及治疗工作有重要意义。     

Reference ranges for natriuretic peptides for diagnostic use are dependent on age, gender and heart rate

BACKGROUND: Plasma natriuretic peptide levels may be useful in the diagnosis of heart failure. The available natriuretic peptide assays differ markedly in their performance characteristics. In addition, plasma levels are influenced by a number of factors including age and gender. AIMS: The aim of this study was to describe, in a healthy population, the influence of clinical and echocardiographic parameters on three natriuretic peptide moieties. METHODS: 1360 individuals were screened for the presence of left ventricular systolic dysfunction. We identified a cohort (n=720) of men aged 45-80 years (n=417) and women aged 55-80 years (n=303). None had history of cardiovascular disease or were taking any cardiovascular medication. All had normal echocardiographic and ECG findings. B-type (BNP), N-terminal pro-B-type (N-BNP) and N-terminal pro-Atrial (N-ANP) natriuretic peptides were assayed using in-house immunoluminometric assays. RESULTS: Of the considered clinical variables, only gender and heart rate (each P<0.005) were independently associated with levels of all three natriuretic peptides. Plasma levels of N-ANP (15%), BNP (25%) and N-BNP (75%) were higher in women compared to men. An increase in heart rate of 10 bpm corresponded to a reduction of 9% in N-ANP or BNP and a 15% reduction in N-BNP. Each 10 years of age was associated with 16% and 74% increase in ANP and N-BNP levels, respectively, but no increase in plasma BNP. Left ventricular ejection fraction could be assessed in 582 (81%) subjects and correlated positively with N-ANP (r(s)=6.48x10(-3), P<0.001) and BNP (r(s)=2.4x10(-2), P<0.001) but not N-BNP (P=0.405). No parameter of diastolic function was associated with any peptide level. CONCLUSIONS: In this healthy population, plasma levels of N-ANP, BNP and N-BNP were variably influenced by clinical covariates. While all three peptides were higher in women, only N-ANP and N-BNP were influenced by age. Levels of all peptides were inversely correlated with heart rate. Using this immunoluminometric assay, plasma BNP is not influenced by age, in contrast to N-ANP and N-BNP. In constructing normal ranges for diagnostic use, covariates such as age and gender must be considered, in addition to the format of assay being used.     

Age‐related changes in blood pressure and heart rates of patients with Parkinson's disease

This study evaluated yearly changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rates (HR) for patients with Parkinson's disease (PD). Data were collected for the last 10 years from medical records of 28 PD patients and 30 non‐PD patients with other neurological disorders. Age‐related changes in each group were analyzed by year using mean values of SBP, DBP, and HR obtained at their bi‐monthly visits. In results, PD patients had a gradual decrease in SBP with longer disease duration, and mean SBP significantly decreased from Year 7–11 compared to the mean values for Year 1 (p < .001 or p < .01). In non‐PD patients, mean SBP significantly increased from Year 4–11 compared to the mean values for Year 1 (p < .001 or p < .01). This is the first study to report age‐related changes of BP in individual patients with PD over 10 years.     

Laboratory reference values for healthy adults from southern Tanzania

Objectives To define and discuss reference ranges for commonly determined laboratory parameters in healthy adults from southern Tanzania. Methods A population‐based sample of adult volunteers from Mbeya, Tanzania, who were not HIV positive or showing signs and symptoms of other diseases, participated in this study. We enrolled 145 women and 156 men between 19 and 48 years of age to determine clinical chemistry (CC), haematology and lymphocyte immunophenotyping (LIP) parameters using standard laboratory methods. Medians and nonparametric 95% reference ranges for each parameter were determined and compared with reference ranges from the USA, Europe and from other African countries. Results Agreement with ranges from developed countries was poor: for CC values the average concordance was 80.9% and 86.7% with values from two developed countries. Haematology ranges from the USA classified 86.3% of values correctly, whereas ranges from three different sub‐Saharan Africa (SSA) sites classified between 82.5% and 94.5% of values correctly. The agreement of LIP reference ranges was 87.5% with values determined in Germany but between 91.7% and 95.8% compared with values determined at other sites in SSA. Conclusion Clinical reference ranges determined in developed countries are inadequate for use in SSA. Laboratories in this region should either define their own or use values determined under similar conditions. The ranges reported here are more appropriate for use in SSA than ranges determined in developed countries.     

Gender‐specific patterns in age‐related decline in general health among Danish and Chinese: A cross‐national comparative study

Aim: Studies carried out in Western populations have shown age‐related changes in multiple health domains together with gender‐specific patterns. By focusing on five health domains, self‐rated health, hand grip strength, sit‐to‐stand test, cognitive performance and depression, we examined the age trajectories in general health in a cross‐sectional Chinese sample representing the world's largest ethnic population and compare with Danish data that represent Western populations in developed countries. Methods: Multiple regression models were fitted to compare patterns across genders and populations together with gender‐ and population‐specific patterns in age‐related decline. Results: Better self‐rated health for males than for females was observed in both countries, and Danes reported better health than the Chinese for both genders. For hand grip strength, significant gender differences were shown across countries and significant population differences observed in Danish and Chinese males. There was no population difference in sit‐to‐stand time across genders. Female Danes outperformed males in cognitive performance. No significant gender differences in depression were observed in both populations. Conclusion: Our cross population analysis identified significant gender and population differences suggesting endogenous biological, physical and social environmental determinants in age‐related decline in general health. Geriatr Gerontol Int 2012; 12: 431–439.     

Reference intervals and percentiles for carotid‐femoral pulse wave velocity in a healthy population aged between 9 and 87 years

There is little information regarding age‐related reference intervals (RIs) of carotid‐femoral pulse wave velocity (cfPWV) for large healthy populations in South America. The aims of this study were to determine cfPWV RIs and percentiles in a cohort of healthy children, adolescents, and adults and to generate year‐to‐year percentile curves and body‐height percentile curves for children and adolescents. cfPWV was measured in 1722 healthy participants with no cardiovascular risk factors (9–87 years, 60% men). First, RIs were evaluated for males and females through correlation and covariate analysis. Then, mean and standard deviation age‐related equations were obtained for cfPWV using parametric regression methods based on fractional polynomials and age‐specific (year‐to‐year) percentile curves that were defined using the standard normal distribution. Age‐specific first, 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentile curves were calculated. Finally, height‐related cfPWV percentile curves for children and adolescents (<21 years) were established. After adjusting for age and blood pressure differences with respect to females, males showed higher cfPWV levels (6.60 vs 6.45 m/s; P < .01). Thus, specific RIs for males and females were reported. The study provides the largest database to date concerning cfPWV in healthy people from Argentina. Specific RIs and percentiles of cfPWV are now available according to age and sex. Specific percentiles of cfPWV according to body height were reported for people younger than 21 years.