Subgroup Analysis via Recursive Partitioning

Subgroup analysis is an integral part of comparative analysis where assessing the treatment effect on a response is of central interest. Its goal is to determine the heterogeneity of the treatment effect across subpopulations. In this paper, we adapt the idea of recursive partitioning and introduce an interaction tree (IT) procedure to conduct subgroup analysis. The IT procedure automatically facilitates a number of objectively defined subgroups, in some of which the treatment effect is found prominent while in others the treatment has a negligible or even negative effect. The standard CART (Breiman et al., 1984) methodology is inherited to construct the tree structure. Also, in order to extract factors that contribute to the heterogeneity of the treatment effect, variable importance measure is made available via random forests of the interaction trees. Both simulated experiments and analysis of census wage data are presented for illustration

COMPARISON OF STATIC BALANCE MEASURES WITH HEIGHT AND WEIGHT ADJUSTMENTS BETWEEN TAEKWONDO AND HANDBALL PLAYERS

This study aimed to compare the static balance of taekwondo athletes and handball players. Considering the body size might affect the sway during static balance testing as the inverted pendulum model demonstrated. The static balance of the subjects was evaluated by the Bidex Balance System. The results showed that the APSI, MLSI and OSI of taekwondo athletes were significantly lower than those of the handball players. Moreover, the three stability indices of the two groups of athletes were significantly correlated with height and weight, but not age. The data showed that body size were positively related to the sway in the static balance testing. The taekwondo athletes were lighter than the handball players in average, nevertheless, lower height-and-weight adjusted stability indices of the taekwondo athletes were found

A Liposomal Formulation Able to Incorporate a High Content of Paclitaxel and Exert Promising Anticancer Effect

A liposome formulation for paclitaxel was developed in this study. The liposomes, composed of naturally unsaturated and hydrogenated phosphatidylcholines, with significant phase transition temperature difference, were prepared and characterized. The liposomes exhibited a high content of paclitaxel, which was incorporated within the segregated microdomains coexisting on phospholipid bilayer of liposomes. As much as 15% paclitaxel to phospholipid molar ratio were attained without precipitates observed during preparation. In addition, the liposomes remained stable in liquid form at 4°C for at least 6 months. The special composition of liposomal membrane which could reduce paclitaxel aggregation could account for such a capacity and stability. The cytotoxicity of prepared paclitaxel liposomes on the colon cancer C-26 cell culture was comparable to Taxol. Acute toxicity test revealed that LD50 for intravenous bolus injection in mice exceeded by 40 mg/kg. In antitumor efficacy study, the prepared liposomal paclitaxel demonstrated the increase in the efficacy against human cancer in animal model. Taken together, the novel formulated liposomes can incorporate high content of paclitaxel, remaining stable for long-term storage. These animal data also demonstrate that the liposomal paclitaxel is promising for further clinical use

Age as a predisposing factor of respiratory alkalosis in accidental carbon monoxide poisoning

AbstractAimsThe purpose of this study was to determine the frequency of and identify the predisposing factors for respiratory alkalosis in patients with accidental carbon monoxide (CO) poisoning.MethodsPatients presenting to the emergency department with accidental CO poisoning were retrospectively identified and divided into Group A (no respiratory alkalosis) and Group B (respiratory alkalosis). Charts were reviewed for neurologic status, various demographic factors, and laboratory data.ResultsA total 96 patients, 37 (38.5%) men and 59 (61.5%) women, were identified. Of these, the 58 (60.4%) patients without respiratory alkalosis were placed in Group A and the 38 (39.6%) patients with respiratory alkalosis were placed in Group B. Independent multivariate predictors of CO poisoning presenting with respiratory alkalosis were age [odds ratio (OR), 1.04; 95% confidence interval (CI), 1.01–1.08] and respiratory rate (OR, 1.16; 95% CI, 1.01–1.33). The rates of respiratory alkalosis in patients younger than 15 years, 15–29 years, 30–44 years, 45–59 years, and older than 59 years were 17.4%, 32.4%, 51.9%, 75%, and 75%, respectively (p<0.01).ConclusionsRespiratory alkalosis in the patients with CO poisoning is not an uncommon finding, and as age increases, the percentage becomes higher. When emergency physicians are faced with patients presenting with respiratory alkalosis of undetermined cause, CO poisoning should be taken into consideration, especially in the elderly

A Bayesian measurement error model for two-channel cell-based RNAi data with replicates

RNA interference (RNAi) is an endogenous cellular process in which small double-stranded RNAs lead to the destruction of mRNAs with complementary nucleoside sequence. With the production of RNAi libraries, large-scale RNAi screening in human cells can be conducted to identify unknown genes involved in a biological pathway. One challenge researchers face is how to deal with the multiple testing issue and the related false positive rate (FDR) and false negative rate (FNR). This paper proposes a Bayesian hierarchical measurement error model for the analysis of data from a two-channel RNAi high-throughput experiment with replicates, in which both the activity of a particular biological pathway and cell viability are monitored and the goal is to identify short hair-pin RNAs (shRNAs) that affect the pathway activity without affecting cell activity. Simulation studies demonstrate the flexibility and robustness of the Bayesian method and the benefits of having replicates in the experiment. This method is illustrated through analyzing the data from a RNAi high-throughput screening that searches for cellular factors affecting HCV replication without affecting cell viability; comparisons of the results from this HCV study and some of those reported in the literature are included.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS496 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Rapid detection of K650E mutation in FGFR3 using uncultured amniocytes in a pregnancy affected with fetal cloverleaf skull, occipital pseudoencephalocele, ventriculomegaly, straight short femurs, and thanatophoric dysplasia type II

AbstractObjectiveTo present the ultrasound and molecular genetic diagnosis of thanatophoric dysplasia type II (TD2).Case ReportA 35-year-old, primigravid woman was referred to our institution for genetic counseling and amniocentesis at 19 weeks of gestation because of advanced maternal age and sonographic abnormalities in the fetus. The prenatal ultrasound showed short straight femurs, prominent forehead, narrow chest, skin edema, short limbs, and cloverleaf skull consistent with the diagnosis of TD2. Amniocentesis revealed a karyotype of 46,XX. DNA testing for the FGFR3 gene using uncultured amniocytes revealed a heterozygous c.1948A>G, AAG>GAG transversion leading to a p.Lys650Glu(K650E) mutation in the FGFR3 gene. A prenatal ultrasound at 21 weeks of gestation showed ventriculomegaly, cloverleaf skull, straight femurs, micromelia, narrow chest, and pseudoencephalocele with a bulging occipital bone mimicking encephalocele. The pregnancy was subsequently terminated, and a 480-g malformed fetus was delivered with macrocephaly, depressed nasal bridge, short upturned nasal tip, hypoplastic midface, frontal bossing, short digits, trident-shaped hands, short limbs, cloverleaf skull, narrow chest, brachydactyly, nuchal edema, and bulging occipital bone.ConclusionA prenatal diagnosis of cloverleaf skull, short limbs, straight femurs, and occipital pseudoencephalocele should include a differential diagnosis of TD2. A molecular analysis of FGFR3 using uncultured amniocytes is useful for the rapid confirmation of TD2 at prenatal diagnosis