Psychometric Evaluation of the Brunei-Malay SF-36 version 2 Health Survey

Objectives: To culturally adapt the Short Form Health-36 version 2 (SF-36v2) into the Brunei-Malay context anddetermine its reliability and validity for measuring health-related quality of life (HRQOL) in healthy individuals andpatients with chronic kidney disease in Brunei Darussalam. Methods: An iterative multistep strategy involving setting upa bilingual expert panel, pretesting, text revision and back translation was used to prepare the Brunei-Malay SF-36v2 asan adaptation from the Malaysian-Malay SF-36v2. The Brunei-Malay SF-36v2 was then self-administered to a sample ofhealthy individuals (n=95) and predialysis chronic kidney disease outpatients (n=95) resident in Brunei. The mean(SD) age of the participants was 46.6 (17.8) years. Results: Data completion rate was 100% with minimal floor effects(≤0.21) in all the 8 domains and >15% ceiling effects in 3 of the 8 domain scales. Cronbach’s alpha was >0.70 for allthe 8 domain scales. Scaling success was 100% for convergent validity, with 100% item discriminant validity for alldomain scales except Social Functioning (94%), Mental Health (85%) and General Health (85%). Principal componentanalysis of the two-factor dimension explained 68% overall variance and accounted for 81% reliable variance, but theexact SF-36 two-factor summary constructs in the standard algorithm were not replicated in the Bruneian population.Conclusions: The Brunei-Malay SF-36v2 is a valid and reliable instrument for measuring HRQOL in healthy individualsand patients with chronic kidney disease in Brunei. The summary scales should, however, be interpreted with caution.Further studies should be carried out to assess additional psychometric properties of the Brunei-Malay SF-36v2.     

Eating practices and behavior in the urban environment: a study in downtown São Paulo

This study focuses on the implications of urban life style on eating habits and the related symbolic representations. Theoretical references used to approach the food experience are the concepts of social representation and habitus. The methodology consisted of a qualitative analysis of interviews with 21 administrative employees and field observations made at commercial establishments in downtown S?o Paulo, such as snack bars and restaurants. Study of eating behavior and practices was developed along two planes: food actually eaten and food desired. Results were classified into three segments: "ingesting and digesting affection", "determinants of social representations of eating practices", and "rituals in eating practices". Due to their origin in a domestic universe, symbolic aspects associated with food have a strong affective matrix. Concrete conditions of the urban environment associated with the subject's financial limits establish a structure of values and feelings compatible with the subject's possibilities. The study addresses both the abbreviation of food rituals and its implications on food behavior as well as features of the present urban food pattern.     

Does a single control mechanism exist for both forward and backward walking?

It has been proposed that the highly reproducible forward walking (FW) locomotor pattern is generated by a central neuronal program or central pattern generator (CPG) which provides the underlying mechanism which produces the coordinated walking movement. The purpose of this study was to quantify the differences in the muscular activation patterns during FW and backward walking (BW) at a constant step frequency and to determine if common features exist across both locomotor conditions. The hypothesis was that FW and BW are both mediated by the same CPG; therefore, only small modifications in the CPG are required in order to produce the different characteristics of each walking mode. The results noted kinematically reversed patterns at the hip and ankle joints between FW and BW. The knee joint movement pattern was similar between conditions, however, a phase shift of 14.3% of the gait cycle occurred. An approximately 25% phase shift in the muscle activation patterns existed between FW and BW in four of the six muscles studied. Additionally, a pattern recognition technique was applied to the combined EMG signals to determine the minimum number of features required to generate the measured muscular output. Only two main features were necessary to produce the EMG patterns for both the FW and BW condition. The main features in FW were more consistent than noted in BW. The results support the notion that a single spinal mechanism such as a CPG with two main features appears to be in control during both FW and BW.     

Prediction of response to antiretroviral therapy by human experts and by the EuResist data‐driven expert system (the EVE study)

Objectives

The EuResist expert system is a novel data‐driven online system for computing the probability of 8‐week success for any given pair of HIV‐1 genotype and combination antiretroviral therapy regimen plus optional patient information. The objective of this study was to compare the EuResist system vs. human experts (EVE) for the ability to predict response to treatment.

Methods

The EuResist system was compared with 10 HIV‐1 drug resistance experts for the ability to predict 8‐week response to 25 treatment cases derived from the EuResist database validation data set. All current and past patient data were made available to simulate clinical practice. The experts were asked to provide a qualitative and quantitative estimate of the probability of treatment success.

Results

There were 15 treatment successes and 10 treatment failures. In the classification task, the number of mislabelled cases was six for EuResist and 6–13 for the human experts [mean±standard deviation (SD) 9.1±1.9]. The accuracy of EuResist was higher than the average for the experts (0.76 vs. 0.64, respectively). The quantitative estimates computed by EuResist were significantly correlated (Pearson r=0.695, P<0.0001) with the mean quantitative estimates provided by the experts. However, the agreement among experts was only moderate (for the classification task, inter‐rater κ=0.355; for the quantitative estimation, mean±SD coefficient of variation=55.9±22.4%).

Conclusions

With this limited data set, the EuResist engine performed comparably to or better than human experts. The system warrants further investigation as a treatment‐decision support tool in clinical practice.     

The apoptotic response in HCT116<Superscript><Emphasis Type="Italic">BAX-/-</Emphasis></Superscript>cancer cells becomes rapidly saturated with increasing expression of a GFP-BAX fusion protein

Background  

Many chemotherapeutic agents promote tumor cell death by activating the intrinsic pathway of apoptosis. Intrinsic apoptosis involves permeabilization of the mitochondrial outer membrane and the release of cytochrome c, a process that is controlled by proteins of the BCL2 gene family. Chemoresistance is often associated with abnormalities in concentrations of BCL2 family proteins. Although stoichiometirc interactions between anti-apoptotic and BH3-only BCL2 family proteins have been well documented as affecting cell death, the association between changes in BAX concentration and intrinsic apoptosis are poorly understood.     

Factors influencing the acceleration of human factor XIa inactivation by antithrombin III

Controversy exists in the literature concerning the potentiating effect of heparin on the inactivation rate of factor XIa by antithrombin III (AT III) in both purified systems and in plasma. We have analyzed the factors that could influence this reaction and found that ionic strength of the medium, as well as the type and concentration of the heparin preparations accounted for the major discrepancies in the literature. At I = 0.43 N, a preparation of bovine lung heparin at 1 U/mL did not augment the inactivation rate of factor XIa by inhibitors in plasma or by purified AT III. However, when ionic strength was decreased, a progressive increase in the potentiating effect was observed, reaching 6.5-fold at I = 0.15 N. At saturating concentrations of heparin, which results in the formation of 100% AT III-heparin complex, (greater than ten-fold molar excess over AT III) in purified systems, all heparin preparations (porcine, bovine, low molecular weight [LMW], and high affinity) yielded an approximately 30-fold augmentation of the factor XIa inactivation rate. However, when heparin was less than saturating, we observed that various heparin preparations affected the AT III-induced inactivation of factor XIa to different degrees even though they exhibited the same inhibitory activity (1 U/mL) against thrombin. This variation resulted from differences in the number of AT III binding sites in each heparin preparation, despite a similar Kd for each. Addition of high molecular weight kininogen (HK) to AT III-heparin complexes did not enhance their ability to inhibit factor XIa, and high concentrations of HK decreased the inactivation rate. A high therapeutic dose of heparin only permits the formation of 2.5% to 16.5% of the AT III-heparin complexes that can be achieved at saturation. We observed that 1 U/mL heparin (bovine lung heparin) (high therapeutic concentration) in virtually undiluted plasma only accelerated the inactivation rate of factor XIa (in the absence of other active enzymes) less than two-fold. These new observations further support our previous conclusion that therapeutic levels of heparin have little to no influence on the inactivation rate of factor XIa in plasma.