Home About us Contact
|
Home About us Contact | ||
|
|
||
Heterogeneous Sample (heterogeneous + sample)
Selected AbstractsDiagnostic performance of clinical motor and non-motor tests of Parkinson disease: a matched case,control studyEUROPEAN JOURNAL OF NEUROLOGY, Issue 7 2008N. I. Bohnen Background and purpose:, The diagnosis of Parkinson disease (PD) is made typically on the basis of motor abnormalities. PD is now recognized to have both motor and non-motor manifestations, indicating a need for the development of reliable non-motor diagnostic tests for PD. The aim of the present study was to compare the accuracy of various clinical motor and non-motor tests for the diagnosis of PD. Methods:, Forty-five PD patients (Hoehn and Yahr stages 1,3; mean age 59.5 ± 10.0 years) and 45 healthy controls matched for gender and age completed a clinimetric motor test battery to assess limb bradykinesia, tremor and balance. Non-motor tests consisted of depression, anxiety and smell identification ratings. Area under the receiver operator characteristic curve (AUC) analysis was used. Results:, We found that smell identification was the most accurate predictor of the presence of PD within the overall group of patients and matched control subjects (AUC = 0.886) and also in the subgroups of mild severity (Hoehn and Yahr stages 1,1.5; AUC = 0.923), young-onset (AUC = 0.888) and female PD patients (AUC = 0.797). The second best diagnostic test was the grooved pegboard test for the clinically most affected body side. Conclusions:, We conclude that olfactory function is the most accurate diagnostic predictor within a heterogeneous sample of patients with PD. [source] The relationship of GMA to counterproductive work behavior revisitedEUROPEAN JOURNAL OF PERSONALITY, Issue 6 2009Bernd Marcus Abstract Recent research reported that general mental ability (GMA) predicted counterproductive work behavior (CWB), whereas some previous studies failed to find such a relationship. We tested occupational homogeneity of the sample and criterion measurement as two potential explanations for these inconsistencies. Study 1 replicated major design features of one previous study, which found no GMA,CWB relation in a heterogeneous sample, with occupationally homogeneous groups. Results confirmed previous null findings, indicating no effect of sample homogeneity. In Study 2, using a controlled laboratory setting, GMA was again unrelated to self-reported CWB, but partially predicted observed CWB negatively. Combined findings suggest that GMA is consistently unrelated to CWB self-reports but may predict objectively measured CWB independently of the likelihood of being caught. Copyright © 2009 John Wiley & Sons, Ltd. [source] Acute Hypervolaemia Improves Arterial Oxygen Pressure in Athletes with Exercise-Induced HypoxaemiaEXPERIMENTAL PHYSIOLOGY, Issue 4 2003Gerald S. Zavorsky The aim of this study was to determine the effect of acute plasma volume expansion on arterial blood-gas status during 6.5 min strenuous cycling exercise comparing six athletes with and six athletes without exercise-induced arterial hypoxaemia (EIAH). We hypothesized that plasma volume expansion could improve arterial oxygen pressure in a homogeneous sample of athletes - those with EIAH. In this paper we have extended the analysis and results of our recently published surprising findings that lengthening cardiopulmonary transit time did not improve arterial blood-gas status in a heterogeneous sample of endurance cyclists. One 500 ml bag of 10% Pentastarch (infusion condition) or 60 ml 0.9% saline (placebo) was infused prior to exercise in a randomized, double-blind fashion on two different days. Power output, cardiac output, oxygen consumption and arterial blood gases were measured during strenuous exercise. Cardiac output and oxygen consumption were not affected by acute hypervolaemia. There were group × condition interaction effects for arterial oxygen pressure and alveolar-arterial oxygen pressure difference, suggesting that those with hypoxaemia experienced improved arterial oxygen pressure (+4 mmHg) and lower alveolar-arterial oxygen pressure difference (-2 mmHg) with infusion. In conclusion, acute hypervolaemia improves blood-gas status in athletes with EIAH. The impairment of gas exchange occurs within the first minute of exercise, and is not impaired further throughout the remaining duration of exercise. This suggests that arterial oxygen pressure is only minimally mediated by cardiac output. [source] Predicting Individual Differences in Recall by Infants Born Preterm and Full TermINFANCY, Issue 1 2006Carol L. Cheatham A heterogeneous sample of infants with preterm histories and infants born full term participated in a study of declarative memory and rate of encoding, as measured in an imitation task and an examining task, respectively. Here we report the comparisons of the performances of infants born very preterm (27,34 weeks gestation) and moderately preterm (35,37 weeks gestation) to infants born full term (38,41 weeks gestation) and tested at 12 months corrected age (from due date). Lower levels of recall were seen among the infants born very preterm. Rate of encoding, weeks gestation, and score on the Mental Development Index (MDI) of the Bayley Scales of Infant Development were tested as possible sources of individual differences in recall. Rate of encoding and MDI predicted delayed ordered recall. Implications for early detection of cognitive difficulties in children with preterm histories are discussed. [source] Prognosis in pediatric hematologic malignancies is associated with serum concentration of mannose-binding lectin-associated serine protease-2 (MASP-2)PEDIATRIC BLOOD & CANCER, Issue 1 2009Aina Zehnder MD Abstract Background Mannose-binding lectin (MBL) and MBL-associated serine protease-2 (MASP-2) are key components of the lectin pathway of complement activation. Their serum concentrations show a wide interindividual variability. This study investigated whether the concentration of MBL and MASP-2 is associated with prognosis in pediatric patients with cancer. Methods In this retrospective multicenter study, MBL and MASP-2 were measured by commercially available ELISA in frozen remnants of serum taken at diagnosis. Associations of overall survival (OS) and event-free survival (EFS) with MBL and MASP-2 were assessed by multivariate Cox regression accounting for prognostically relevant clinical variables. Results In the 372 patients studied, median serum concentration of MBL was 2,808 µg/L (range, 2,10,060) and 391 µg/L (46,2,771) for MASP-2. The estimated 4-year EFS was 0.60 (OS, 0.78). In the entire, heterogeneous sample, MBL and MASP-2 were not significantly associated with OS or EFS. In patients with hematologic malignancies, however, higher MASP-2 was associated with better EFS in a significant and clinically relevant way (hazard ratio per tenfold increase (HR), 0.22; 95% CI, 0.09,0.54; P,=,0.001). This was due to patients with lymphoma (HR, 0.11; 95% CI, 0.03,0.47; P,=,0.003), but less for those with acute leukemia (HR, 0.35; 95% CI, 0.11,1.15; P,=,0.083). Conclusion In this study, higher MASP-2 was associated with better EFS in pediatric patients with hematologic malignancies, especially lymphoma. Whether MASP-2 is an independent prognostic factor affecting risk stratification and anticancer therapy needs to be assessed in prospective, disease-specific studies. Pediatr Blood Cancer 2009;53:53,57. © 2009 Wiley-Liss, Inc. [source] Posttraumatic growth in cancer patients and partners,effects of role, gender and the dyad on couples' posttraumatic growth experiencePSYCHO-ONCOLOGY, Issue 1 2010Diana Zwahlen Abstract Background/Aim: Little is known about factors influencing positive effects in couples facing a cancer diagnosis. Methods: A heterogeneous sample of 224 couples from a multi-site study (four oncology units) completed questionnaire surveys including the Posttraumatic Growth Inventory (PTGI) as a measure of positive psychological effects. Results: The data demonstrated that all three investigated factors,gender, role (patient vs partner) and the dyad (belonging to any of the 224 couples),significantly contributed to variation in PTGI total scores and subscales. Variability between couples (factor dyad) appeared stronger than variability between patient and partner participants (factor role) and between male and female participants (factor gender). Role and gender analysis showed that patients demonstrated higher levels of posttraumatic growth than partners; and female participants scored higher on PTGI than males. Male patient,female partner pairs show greater association in their experience of posttraumatic growth than female patient,male partner pairs. Correlations also suggested that, regardless of the gender and role composition, patients and partners may experience parallel growth. Conclusions: Our findings indicate that positive psychological experiences may be shared by partners affected by cancer in similar ways as have been shown for negative psychological effects. Intra-couple similarities or processes may have a more important function in experiencing benefits than factors like gender or being the patient or the partner. These results underline the importance of a family approach to understanding negative and positive psychological effects of cancer. Copyright © 2009 John Wiley & Sons, Ltd. [source] Comparison of ADHD symptom subtypes as source-specific syndromesTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 6 2004Kenneth D. Gadow Background:, This study examines differences between the three subtypes of attention-deficit/hyperactivity disorder (ADHD), inattentive (I), hyperactive-impulsive (H), and combined (C), in a heterogeneous sample of 248 boys (ages 6 to 10 years) with emotional and behavioral problems who were recruited for participation in a diagnostic study. Method:, The boys and their mothers participated in an extensive evaluation that involved multiple assessments of cognitive, behavioral, academic, and family functioning. ADHD subtypes were defined on the basis of teacher alone, mother alone, and mother/teacher ratings of DSM-IV symptoms. Results:, Results indicated ADHD symptom groups showed a differential pattern of impairment socially (H,C>I) and cognitively (I,C>H). The C and H groups were the most and least impaired overall, respectively, and all subtypes were differentiated from the nonADHD clinical control or NONE (N) group in a manner consistent with the primary findings. External validation of group differences was limited, and there were marked inconsistencies in the pattern of findings depending on how groups were defined. For the most part, although the mother/teacher grouping strategy (compared with either alone) captured a greater diversity of differences between subtypes, it also obscured some. Conclusions:, Observed findings are consistent with the notion that mothers and teachers interpret symptom statements in terms of behaviors that are most relevant for their daily concerns. [source] On the inversion of multicomponent NMR relaxation and diffusion decays in heterogeneous systemsCONCEPTS IN MAGNETIC RESONANCE, Issue 2 2005Raffaele Lamanna Abstract The analysis of the decay of NMR signals in heterogeneous samples requires the solution of an ill-posed inverse problem to evaluate the distributions of relaxation and diffusion parameters. Laplace transform is the most widely accepted algorithm used to describe the NMR decay in heterogeneous systems. In this article we suggest that a superposition of Fredholm integrals, with different kernels, is a more suitable model for samples in which liquid and solid-like phases are both present. In addition, some algorithms for the inversion of Laplace and Fredholm inverse problems are illustrated. The quadrature methods and regularization function in connection with the use of nonlinear discretization grids are also discussed. The described inversion algorithms are tested on simulated and experimental data, and the role of noise is discussed. © 2005 Wiley Periodicals, Inc. Concepts Magn Reson Part A 26A: 78,90, 2005 [source] Magnetic susceptibility: Further insights into macroscopic and microscopic fields and the sphere of LorentzCONCEPTS IN MAGNETIC RESONANCE, Issue 1 2003C.J. Durrant Abstract To make certain quantitative interpretations of spectra from NMR experiments carried out on heterogeneous samples, such as cells and tissues, we must be able to estimate the magnetic and electric fields experienced by the resonant nuclei of atoms in the sample. Here, we analyze the relationships between these fields and the fields obtained by solving the Maxwell equations that describe the bulk properties of the materials present. This analysis separates the contribution to these fields of the molecule in which the atom in question is bonded, the "host" fields, from the contribution of all the other molecules in the system, the "external" fields. We discuss the circumstances under which the latter can be found by determining the macroscopic fields in the sample and then removing the averaged contribution of the host molecule. We demonstrate that the results produced by the, so-called, "sphere of Lorentz" construction are of general validity in both static and time-varying cases. This analytic construct, however, is not "mystical" and its justification rests not on any sphericity in the system but on the local uniformity and isotropy, i.e., spherical symmetry, of the medium when averaged over random microscopic configurations. This local averaging is precisely that which defines the equations that describe the macroscopic fields. Hence, the external microscopic fields, in a suitably averaged sense, can be estimated from the macroscopic fields. We then discuss the calculation of the external fields and that of the resonant nucleus in NMR experiments. © 2003 Wiley Periodicals, Inc. Concepts Magn Reson Part A 18A: 72,95, 2003 [source] High phenotypic diversity in infecting but not in colonizing Staphylococcus aureus populationsENVIRONMENTAL MICROBIOLOGY, Issue 12 2007Christiane Goerke Summary In hostile environments diversity within a bacterial population may be beneficial for the fitness of the microbial community as a whole. Here we analysed the population diversity of Staphylococcus aureus in infecting and colonizing situations. In the study, performed independently in two German centres, the heterogeneity of the S. aureus population was determined by quantifying the occurrence of phenotypic variants (differences in haemolysis, pigmentation, colony morphology) in primary cultures from nose, oropharyngeal and sputum specimens from cystic fibrosis (CF) patients and in nose swabs from healthy S. aureus carriers. The proportion of heterogeneous samples, the number of clearly distinguishable isolates per sample and the qualitative differences between phenotypes was significantly higher in CF sputum specimens than in the other samples. The heterogeneity of the S. aureus population could be correlated with high bacterial densities in the sputum samples. In patients co-infected with Pseudomonas aeruginosa lower S. aureus bacterial loads and less heterogeneity in the S. aureus population were observed. Typing of all S. aureus isolates from heterogeneous samples by pulsed-field gel electrophoresis or spa typing revealed that the bacteria were polyclonal in 30%, monoclonal with minor genetic alterations in 25% or not distinguishable in 69% of the specimens. Some specimens harboured monoclonal and polyclonal variants simultaneously. Importantly, differences in antibiotic susceptibility were detected in phenotypic S. aureus variants within a single specimen. Diversification of a S. aureus population is highly favoured during chronic CF lung infection, supporting the general hypothesis that maintenance of intrahost diversity can be of adaptive value, increasing the fitness of the bacterial community. [source] Men and health help-seeking behaviour: literature reviewJOURNAL OF ADVANCED NURSING, Issue 6 2005Paul M. Galdas BSc RN CertEd Aim., This paper reviews the key research literature regarding men's health-related help seeking behaviour. Background., There is a growing body of research in the United States to suggest that men are less likely than women to seek help from health professionals for problems as diverse as depression, substance abuse, physical disabilities and stressful life events. Previous research has revealed that the principle health related issue facing men in the UK is their reluctance to seek access to health services. Method., The investigation of men's health-related help seeking behaviour has great potential for improving both men and women's lives and reducing national health costs through the development of responsive and effective interventions. A search of the literature was conducted using CINAHL, MEDLINE, EMBASE, PsychINFO and the Cochrane Library databases. Results., Studies comparing men and women are inadequate in explaining the processes involved in men's help seeking behaviour. However, the growing body of gender-specific studies highlights a trend of delayed help seeking when they become ill. A prominent theme among white middle class men implicates ,traditional masculine behaviour' as an explanation for delays in seeking help among men who experience illness. The reasons and processes behind this issue, however, have received limited attention. Conclusions., Principally, the role of masculine beliefs and the similarities and differences between men of differing background requires further attention, particularly given the health inequalities that exist between men of differing socio-economic status and ethnicity. Further research using heterogeneous samples is required in order to gain a greater understanding of the triggers and barriers associated with the decision making process of help seeking behaviour in men who experience illness. [source] Spatially-localized correlation of dGEMRIC-measured GAG distribution and mechanical stiffness in the human tibial plateauJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2005Joseph T. Samosky Abstract The concentration of glycosaminoglycan (GAG) in articular cartilage is known to be an important determinant of tissue mechanical properties based on numerous studies relating bulk GAG and mechanical properties. To date limited information exists regarding the relationship between GAG and mechanical properties on a spatially-localized basis in intact samples of native tissue. This relation can now be explored by using delayed gadolinium-enhanced MRI of cartilage (dGEMRIC,a recently available non-destructive magnetic resonance imaging method for measuring glycosaminoglycan concentration) combined with non-destructive mechanical indentation testing. In this study, three tibial plateaus from patients undergoing total knee arthroplasty were imaged by dGEMRIC. At 33,44 test locations for each tibial plateau, the load response to focal indentation was measured as an index of cartilage stiffness. Overall, a high correlation was found between the dGEMRIC index (T) and local stiffness (Pearson correlation coefficients r = 0.90, 0.64, 0.81; p < 0.0001) when the GAG at each test location was averaged over a depth of tissue comparable to that affected by the indentation. When GAG was averaged over larger depths, the correlations were generally lower. In addition, the correlations improved when the central and peripheral (submeniscal) areas of the tibial plateau were analyzed separately, suggesting that a factor other than GAG concentration is also contributing to indentation stiffness. The results demonstrate the importance of MRI in yielding spatial localization of GAG concentration in the evaluation of cartilage mechanical properties when heterogeneous samples are involved and suggest the possibility that the evaluation of mechanical properties may be improved further by adding other MRI parameters sensitive to the collagen component of cartilage. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] ,Green earths': vibrational and elemental characterization of glauconites, celadonites and historical pigmentsJOURNAL OF RAMAN SPECTROSCOPY, Issue 8 2008Francesca Ospitali Abstract ,Green earths' are employed since antiquity as pigments in the creation of artworks. The minerals responsible for the colour belong to four groups: (1) the clayey micas celadonite and glauconite, undoubtedly the most common; (2) smectites; (3) chlorites; (4) serpentines. Whereas there have been several studies on clayey materials, mineralogical analyses in the field of cultural heritage are mainly limited to the identification of the green earth without specific characterization of the mineralogical species. This work shows a preliminary characterization by the multi-techniques approach of some raw minerals (glauconite, celadonite and ferroceladonite). Vibrational analyses have been correlated with elemental analyses, thanks to the hyphenated instrumentation of scanning electron microscopy with EDS and Raman structural and chemical analyser (SEM-EDS-SCA) probes, which permitted collection of EDS and Raman spectra on the same microscopic area. Micro-Raman and Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopies were able to distinguish between celadonite and glauconite. The use of different lasers revealed resonance effects in the Raman spectra. In addition to pure minerals, archaeological samples and commercial green earths were also analysed, thereby enabling a more precise classification of the green pigments in heterogeneous samples such as wall paintings. Some commercially available green earths were found to contain organic dyes. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||||||||