Performance in population models for count data,part II: A new SAEM algorithm

Analysis of count data from clinical trials using mixed effect analysis has recently become widely used. However, algorithms available for the parameter estimation, including LAPLACE and Gaussian quadrature (GQ), are associated with certain limitations, including bias in parameter estimates and the long analysis runtime. The stochastic approximation expectation maximization (SAEM) algorithm has proven to be a very efficient and powerful tool in the analysis of continuous data. The aim of this study was to implement and investigate the performance of a new SAEM algorithm for application to count data. A new SAEM algorithm was implemented in MATLAB for estimation of both, parameters and the Fisher information matrix. Stochastic Monte Carlo simulations followed by re-estimation were performed according to scenarios used in previous studies (part I) to investigate properties of alternative algorithms (Plan et al., 2008, Abstr 1372 []). A single scenario was used to explore six probability distribution models. For parameter estimation, the relative bias was less than 0.92% and 4.13% for fixed and random effects, for all models studied including ones accounting for over- or under-dispersion. Empirical and estimated relative standard errors were similar, with distance between them being <1.7% for all explored scenarios. The longest CPU time was 95 s for parameter estimation and 56 s for SE estimation. The SAEM algorithm was extended for analysis of count data. It provides accurate estimates of both, parameters and standard errors. The estimation is significantly faster compared to LAPLACE and GQ. The algorithm is implemented in Monolix 3.1, (beta-version available in July 2009).     

C反应蛋白检测在临床急性感染诊断和治疗中的应用

目的 研究急性时相C反应蛋白（CRP）与WBC计数的关系以及二者在急性期和恢复期的变化，尤其是对于肿瘤并发急性感染诊疗的应用价值。方法 我们检测了非肿瘤组和肿瘤组共136例住院患者血清CRP水平和外周血WBC计数，并在感染恢复期作了复查。结果 非种瘤组血清CRP水平和外周血WBC计数密切相关，肿瘤组二者无相关性。结论 对于肿瘤患者并发急性感染的诊断和疗效判断，急性时相CRP比WBC计数有更大的价值，急性时相CRP检测是诊断急性感染的敏感性指标。     

针挑治疗精索静脉曲张不育术后的临床观察

目的:观察针挑疗法对精索静脉曲张不育手术后的临床疗效.方法:将122例患者随机分为两组,治疗组(62例)针挑骶丛神经点、腰2神经点,对照组(60例)肌肉注射人绒毛膜促性腺激素.结果:配偶受孕率治疗组为79.0%,对照组为41.7%,两组比较差异有非常显著性意义(P<0.01);两组生殖内分泌激素治疗后均有改善(P<0.01);治疗组治疗后精浆超氧化物歧化酶、微量元素锌显著增加,与治疗前比较差异有显著性意义(P<0.05).结论:针挑治疗精索静脉曲张不育术后有显著改善和调节内分泌功能、提高精浆与精子质量、增加妊娠率的作用.     

Prognostic impact of preoperative NLR and CA19-9 in pancreatic cancer

BackgroundRecently, several preoperative proinflammatory markers and nutritional factors such as neutrophil-to-lymphocyte ratio (NLR) and prognostic nutrition index (PNI) have been reported as significant predictor for poor prognosis of various malignant tumors. In this study, we evaluated the prognostic values of these preoperative parameters in patients with resectable pancreatic head cancer.MethodsWe retrospectively reviewed consecutive patients who underwent PD for pancreatic head cancer between 2007 and 2012. A total of 46 patients were enrolled in this analysis. Preoperative parameters such as CRP, CA19-9, NLR and PNI at the time of presentation were recorded as well as overall survival. Cancer specific survival was assessed using Kaplan–Meier method. Univariate and multivariate Cox regression models were applied to evaluate the prognostic relevance of preoperative parameters. The correlations between CA19-9 values, NLR and pathological findings, first recurrence site were respectively reviewed.ResultsIn multivariable analysis preoperative high NLR (≧2.7) and high CA19-9 (≧230) were independent prognostic factors for poor survival (P value: 0.03 and 0.025, respectively). Kaplan–Meier survival analysis demonstrated the overall 2-year survival rate in patients with high NLR or high CA19-9 were 37.5% compared with 89.9% in patients with low NLR and low CA19-9.ConclusionPreoperative NLR and serum CA19-9 offer significant prognostic information associated with overall survival following PD in the patients with pancreatic head cancer.     

Use of Platelet Indices for Determining Illness Severity and Predicting Prognosis in Critically Ⅲ Patients

Background:Decreased platelet (PLT) count is one of the independent risk factors for mortality in intensive care unit (ICU) patients.This study was to investigate the relationship between PLT indices a...     

Plasma D -Lactate Levels in Diagnosis of Appendicitis

We investigated the possible use of D -lactate as a predictor in the diagnosis of appendicitis. C-reactive protein level (CRP) and leukocyte counts were also evaluated. Venous blood D -lactate, CRP, and leukocyte counts were measured preoperatively in 53 patients undergoing surgery for appendicitis, as well as in 20 healthy subjects. Levels of all three parameters in the surgical patients were significantly higher than in the control group ( p < .05). Previous studies have shown that venous D -lactate is more specific to the intestine than CPR or leukocyte count. Based on our data, venous D -lactate, which had the lowest false-negative rate among these laboratory parameters, may be a useful diagnostic marker for appendicitis. None of these parameters were helpful in identifying the type of the appendicitis.     

Combining NSAM and CPC concentrations to determine airborne nanoparticle count median diameter: Application to various laboratory and workplace aerosols

Because nanomaterials have been increasingly developed and used in many technology and industry sectors over the last 20 years, an increasing number of workers is likely to be exposed to airborne nanoparticles. In addition, the question of the nanomaterial characteristics that should be assessed in epidemiological studies remains open. Thus, assessing occupational exposure to airborne nanoparticles will not only rely on mass concentration and chemical composition. Rather, key parameters, such as particle size, have to be included in measurement strategies.

We previously proposed a methodology to estimate the Count Median Diameter (CMD) of an aerosol based on the simultaneous size-integrated measurement of two particle concentrations, lung-deposited surface area, and number, thanks to field-portable, commercially available aerosol instruments (Nanoparticle Surface Area Monitor/Condensation Particle Counter combination).

In addition to previous work, this study investigates the case of various polydisperse metal oxides, organic oil, and salt particles with CMDs ranging from 16–410 nm. Once corrected, the CMDs derived from the NSAM/CPC agree within ±20% with regard to the reference electrical mobility equivalent diameter, regardless of aerosol composition, morphology, or geometric standard deviation (GSD).

Furthermore, the field-applicability of the method was tested through 6 sets of experimental data stemming from workplace measurement campaigns where different materials were produced and handled (TiO₂, SiO₂, Ag, Multi-Walled Carbon Nanotubes—MWCNT), covering a range of CMDs between 40 and 190 nm. All situations considered, the approach based on the combination of a NSAM and a CPC leads to a satisfying estimation of particle CMD, within ±20% compared to reference CMD.     

Measuring the effects of reducing subsidies for private insurance on public expenditure for health care

This paper investigates the effects of reducing subsidies for private health insurance on public sector expenditure for hospital care. An econometric framework using simultaneous equation models is developed to analyse the interrelated decisions on the intensity and type of health care use and private insurance. The framework is applied to the context of the mixed public–private system in Australia. The simulation projections show that reducing premium subsidies is expected to generate net cost savings. This arises because the cost savings achieved from reducing subsidies are larger than the potential increase in public expenditure on hospital care.     

Timing of clamping and factors associated with iron stores in full-term newborns

OBJECTIVE

To analyze the impact of timing of clamping and obstetric, biological and socioeconomic factors on the iron stores of full-term newborns.

METHODS

Cross-sectional study between October 2011 and July 2012 in which hematological parameters were evaluated for newborns in Viçosa, MG, Southeastern Brazil. It involved collecting 7 mL of umbilical cord blood from 144 full-term not underweight newborns. The parameters investigated were complete blood count, serum iron, ferritin and C-reactive protein. The time of umbilical cord clamping was measured using a digital timer without interfering in the procedures of childbirth. The birth data were collected from Live Birth Certificates and other information was obtained from the mother through a questionnaire applied in the first month postpartum. Analysis of multiple linear regression was then used to estimate the influence of biological, obstetrics and socioeconomic factors on the ferritin levels at birth.

RESULTS

The median ferritin was 130.3 µg/L (n = 129, minimum = 16.4; maximum = 420.5 µg/L), the mean serum iron was 137.9 μg/dL (n = 144, SD = 39.29) and mean hemoglobin was 14.7 g/dL (n = 144, SD = 1.47). The median time of cord clamping was 36 seconds, ranging between 7 and 100. The bivariate analysis detected an association between ferritin levels and color of the child, timing clamping of 60 seconds, type of delivery, the presence of gestational diabetes and per capita family income. In multivariate analysis, the variables per capita income, number of antenatal visits and length at birth accounted for 22.0% of variation in ferritin levels.

CONCLUSIONS

Iron stores at birth were influenced by biological, obstetric and social characteristics. Tackling anemia should involve creating policies aimed at reducing social inequalities, improving the quality of antenatal care, as well as implementing a criterion of delayed clamping of the umbilical cord within the guidelines of labor.     

离心法尿沉渣计数尿液最佳体积研究

目的:研究用不同尿量离心沉淀,观察其离心有效性和对细胞计数结果准确性的影响。方法:以红细胞尿液为标本,分别用5.0ml、2.5ml、1.0ml三个不同尿量进行离心和不离心方法的细胞计数,检测结果用t检验统计分析。结果:1.0m尿量进行离心和不离心方法的细胞计数结果无显著差异(P>0.05),5.0ml和2.5ml、细胞计数结果具有显著差异P<0.05。结论:采用1.0ml尿量进行离心法细胞计数可以确保细胞成分离心沉淀完全,细胞计数结果准确。