Urinary creatinine concentrations in the U.S. population: implications for urinary biologic monitoring measurements

Biologic monitoring (i.e., biomonitoring) is used to assess human exposures to environmental and workplace chemicals. Urinary biomonitoring data typically are adjusted to a constant creatinine concentration to correct for variable dilutions among spot samples. Traditionally, this approach has been used in population groups without much diversity. The inclusion of multiple demographic groups in studies using biomonitoring for exposure assessment has increased the variability in the urinary creatinine levels in these study populations. Our objectives were to document the normal range of urinary creatinine concentrations among various demographic groups, evaluate the impact that variations in creatinine concentrations can have on classifying exposure status of individuals in epidemiologic studies, and recommend an approach using multiple regression to adjust for variations in creatinine in multivariate analyses. We performed a weighted multivariate analysis of urinary creatinine concentrations in 22,245 participants of the Third National Health and Nutrition Examination Survey (1988-1994) and established reference ranges (10th-90th percentiles) for each demographic and age category. Significant predictors of urinary creatinine concentration included age group, sex, race/ethnicity, body mass index, and fat-free mass. Time of day that urine samples were collected made a small but statistically significant difference in creatinine concentrations. For an individual, the creatinine-adjusted concentration of an analyte should be compared with a "reference" range derived from persons in a similar demographic group (e.g., children with children, adults with adults). For multiple regression analysis of population groups, we recommend that the analyte concentration (unadjusted for creatinine) should be included in the analysis with urinary creatinine added as a separate independent variable. This approach allows the urinary analyte concentration to be appropriately adjusted for urinary creatinine and the statistical significance of other variables in the model to be independent of effects of creatinine concentration.     

Parathyroid adenomas evaluated by Tl-201/Tc-99m pertechnetate subtraction scintigraphy and high-resolution ultrasonography

Thallium-201/technetium-99m pertechnetate subtraction scintigraphy of the parathyroid glands was performed in a prospective study of 33 patients who had undergone bilateral neck exploration for elevated serum calcium and serum parathyroid hormone levels. In 31 cases, the Tl-201/Tc-99m subtraction technique yielded an overall sensitivity of 81%, specificity of 99%, and accuracy of 94% for identifying solitary parathyroid adenomas. Tl-201/Tc-99m subtraction scintigraphy correctly identified 73% of parathyroid adenomas weighing less than 499 mg, 79% of those weighing 500-1,499 mg, and 100% of adenomas weighing more than 1,500 mg. In a subgroup of 24 patients with solitary parathyroid adenomas who underwent both scintigraphy and high-resolution sonography, the sensitivity, specificity, and accuracy of both procedures were similar.     

Immunoblotting characterization of neutrophil antigenic targets in autoimmune neutropenia

We characterized neutrophil autoantigens using an immunoblotting technique with antibodies obtained from patients with autoimmune neutropenia. These results were correlated with serologic characterization of the antibodies, using indirect immunofluorescence and leukoagglutination. Of the 17 sera immunoblotted, 16 showed discrete bands in the molecular weight range of 30 to 112. Three patients with Felty's syndrome reacted with an antigenic target of 80 to 84 Kd molecular mass, a finding not seen in any of the other patients studied. By serologic testing, none of the autoimmune sera showed serologic specificity for any known neutrophil-specific alloantigen. Using an anti-NA-1 serum, we identified antigenic targets at 40, 50, and 101 Kd in both NA-1-positive and NA-1-negative neutrophils. Ten of 17 autoimmune sera showed reactivity in this corresponding range. These studies demonstrate that immunoblotting may be used to identify antigenic targets in autoimmune neutropenia and may suggest a specificity of these antibodies not definable by serologic techniques. Correlation of immunoblot reactivity with disease states associated with immune neutropenia may be useful in the study of the pathogenesis of the different forms of autoimmune neutropenia.     

心肌坏死标记物在检测心肌坏死中的应用与地位

目的:评估各种心肌坏死标记物对判断心肌坏死的价值。资料来源:应用计算机检索LWW全文英文数据库1994-01/2006-08与心肌坏死标记物相关的文献,检索词“Myocardial damage,myocardiolysis,marker”,并限定文章语言种类为“English”。资料选择:对资料进行初审,选对于临床有意义的心肌坏死物进行较详细的总结。选择临床研究的文章,无论有无对照组、是否为随机对照文献均纳入;排除观察对象为动物的基础研究和综述类文献。资料提炼:对收集到的文献进一步查找全文,凡是对于心肌坏死检测快速且可靠的心肌坏死物优先选择,研究内容相似的,以近3年且发表在较权威杂志者优先,最后纳入30篇关于心肌坏死标记物的文章进行综述。资料综合:急性血栓形成及其随后的心肌损伤、坏死是急性心肌梗死的最主要特征,准确、快速、可靠地检测血栓形成和心肌坏死标志物对内科医生诊断急性心肌梗死极具价值。研究表明缺血修饰白蛋白、心肌型脂肪酸结合蛋白、髓过氧化物酶、CK-MB和心肌肌钙蛋白对急性心肌梗死的诊断各具特点,而联合检测更有助于早期、准确诊断急性心肌梗死,为尽早抢救急性心肌梗死创造时机。结论:缺血修饰白蛋白、心肌型脂肪酸结合蛋白、髓过氧化物酶、CK-MB和心肌肌钙蛋白是较敏感的心肌坏死标记物,联合应用诊断价值更大。     

A multicenter study to evaluate pain characteristics in osteogenesis imperfecta

The objective was to describe pain characteristics and treatments used in individuals with varying severity of osteogenesis imperfecta (OI) and investigate pain-associated variables. This work was derived from a multicenter, longitudinal, observational, natural history study of OI conducted at 12 clinical sites of the NIH Rare Diseases Clinical Research Network's Brittle Bone Disorders Consortium. Children and adults with a clinical, biochemical, or molecular diagnosis of OI were enrolled in the study. We did a cross-sectional analysis of chronic pain prevalence, characteristics, and treatments used for pain relief and longitudinal analysis to find the predictors of chronic pain. We included 861 individuals with OI, in 41.8% chronic pain was present, with similar frequency across OI types. Back pain was the most frequent location. Nonsteroidal anti-inflammatory drugs followed by bisphosphonates were the most common treatment used. Participants with chronic pain missed more days from school or work/year and performed worse in all mobility metrics than participants without chronic pain. The variables more significantly associated with chronic pain were age, sex, positive history of rodding surgery, scoliosis, other medical problems, assistive devices, lower standardized height, and higher body mass index. The predictors of chronic pain for all OI types were age, use of a wheelchair, and the number of fractures/year. Chronic pain is prevalent in OI across all OI types, affects mobility, and interferes with participation. Multiple covariates were associated with chronic pain.     

Prevalence of RET/PTC rearrangements in Hashimoto's thyroiditis and papillary thyroid carcinomas

The relationship between Hashimoto's thyroiditis (HT) and follicular cell-derived thyroid cancer remains unclear. Recently, 2 studies reported a 95% prevalence of RET/PTC rearrangements in histologically benign tissue affected by HT, suggesting that multiple occult tumors exist in HT patients with high frequency. We tested the prevalence of RET/PTC rearrangements in 26 HT, in 6 papillary carcinomas arising in the background of HT, and in 27 papillary carcinomas not associated with HT. We detected no RET/PTC rearrangements in HT or papillary carcinomas arising in the background of HT, in contrast to a 33% prevalence among papillary carcinomas not associated with HT. However, the expression of wild-type RET was found in more than half of papillary carcinomas. These results suggest that, if the association between HT and thyroid cancer exists, its molecular basis is different from RET/PTC rearrangement.