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Linear Regression Analysis (linear + regression_analysis)

Distribution by Scientific Domains
Medical Sciences70%
Life Sciences14%
Chemistry5%
Earth and Environmental Science4%
4 Other Domains7%
Distribution within Medical Sciences
Cardiovascular Disease5%
Neurology4%
Gastroenterology & Hepatology2%
49 Other Subdomains68%

Kinds of Linear Regression Analysis

  • multiple linear regression analysis
  • multivariable linear regression analysis
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  • multivariate linear regression analysis
  • simple linear regression analysis
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    Selected Abstracts

    Performance of the Panleucogating protocol for CD4+ T cell enumeration in an HIV dedicated laboratory facility in Barbados,,

    CYTOMETRY, Issue S1 2008
    Namrata Sippy-Chatrani
    Abstract Objective: To compare the Panleucogating (PLG) protocol with the routinely used four-color protocol for CD4+ T cell count enumeration. Design and Methods: One hundred fifty-three blood samples were randomly selected from samples received at the National HIV Laboratory for routine immunological monitoring. Samples were prepared using Coulter CYTO-STAT® tetraCHROME monoclonal antibodies and FlowCAREÔ PLG CD4 reagent for four-color and PLG, respectively, and analyzed on the Beckman Coulter EPICS XL flow cytometer. The PLG protocol used a sequential gating strategy where CD4+ T cells were identified using side scatter properties of cells and CD45 staining. The four-color protocol used CD45 and CD3 to identify CD4+ T cells. Results: Absolute CD4+ T cell counts and percentages ranged from 4 to 1,285 cells/,L and 0.9 to 46.7%, respectively. Linear regression analyses revealed good correlation of PLG with the four-color protocol (absolute counts, R2 = 0.95; percentages, R2 = 0.98) over the entire range including the clinically relevant range. Bland Altman statistics revealed no bias for CD4 counts <500 cells/,L and a slight underestimation by PLG for counts >500 cells/,L (Bias = ,32.7 cells/,L; 95% agreement limits = ,151.3, +86.0). CD4+ T cell percentages were the similar over the entire range (Bias = 0.6%; 95% agreement limits = ,1.97 ± 3.18). Conclusions: PLG is an accurate method for enumerating CD4+ T cells and has resulted in major cost savings to the Government of Barbados. This has implications for the sustainability of the National HIV containment program in Barbados and the other resource limited Caribbean countries. The PLG technique is now being routinely used in Barbados. © 2008 Clinical Cytometry Society [source]

    ,Numbness of the feet' is a poor indicator for polyneuropathy in Type 2 diabetic patients

    DIABETIC MEDICINE, Issue 2 2000
    L. V. Franse
    Summary Aims To identify neuropathic sensory symptoms associated with a clinical neurological examination (CNE) and to investigate whether these symptoms could be used as a diagnostic or screening tool for diabetic polyneuropathy in general practice. Methods Five hundred and eighty-eight patients with Type 2 diabetes, recruited from 26 general practices in the Netherlands, underwent a CNE and completed a diabetes symptom checklist that included 10 items on neuropathic sensory symptoms. Linear regression analyses were performed to assess the association between neuropathic symptoms and CNE. Receiver operating characteristic (ROC) curves were created to assess the diagnostic properties of neuropathic symptoms. Results In this population, with a mean age of 66.8 years, 32% were identified with diabetic polyneuropathy according to the CNE. Variables that showed the strongest association with CNE score were age (, = 0.41), symptoms of sensory alteration (, = 0.27), and the item ,numbness of the feet' (, = 0.35) in particular. ROC curves showed that prediction of diabetic polyneuropathy from these symptoms was unsatisfying. The sensitivity and specificity of daily symptoms of ,numbness of the feet' were 28% and 93%, respectively, in patients <,68 years, and 22% and 92%, respectively, in patients ,,68 years. Conclusions Identification of neuropathic sensory symptoms is not useful as a diagnostic or even a screening tool in the assessment of diabetic neuropathy in daily practice. Therefore, the results reported in this paper mandate an annual foot examination by the general practitioner. [source]

    Catheterization,Doppler Discrepancies in Nonsimultaneous Evaluations of Aortic Stenosis

    ECHOCARDIOGRAPHY, Issue 5 2005
    Payam Aghassi M.D.
    Prior validation studies have established that simultaneously measured catheter (cath) and Doppler mean pressure gradients (MPG) correlate closely in evaluation of aortic stenosis (AS). In clinical practice, however, cath and Doppler are rarely performed simultaneously; which may lead to discrepant results. Accordingly, our aim was to ascertain agreement between these methods and investigate factors associated with discrepant results. We reviewed findings in 100 consecutive evaluations for AS performed in 97 patients (mean age 72 ± 10 yr) in which cath and Doppler were performed within 6 weeks. We recorded MPG, aortic valve area (AVA), cardiac output, and ejection fraction (EF) by both methods. Aortic root diameter, left ventricular end-diastolic dimension (LVIDd) and posterior wall thickness (PWT) were measured by echocardiography and gender, heart rate, and heart rhythm were also recorded. An MPG discrepancy was defined as an intrapatient difference > 10 mmHg. Mean pressure gradients by cath and Doppler were 36 ± 22 mmHg and 37 ± 20 mmHg, respectively (P = 0.73). Linear regression showed good correlation (r = 0.82) between the techniques. An MPG discrepancy was found in 36 (36%) of 100 evaluations; in 19 (53%) of 36 evaluations MPG by Doppler was higher than cath, and in 17 (47%) of 36, it was lower. In 33 evaluations, EF differed by >10% between techniques. Linear regression analyses revealed that EF difference between studies was a significant predictor of MPG discrepancy (P = 0.004). Women had significantly higher MPG than men by both cath and Doppler (43 ± 25 mmHg versus 29 ± 15 mmHg [P = 0.001]; 42 ± 23 mmHg versus 32 ± 15 mmHg [P = 0.014], respectively). Women exhibited discrepant results in 23 (47%) of 49 evaluations versus 13 (25%) of 51 evaluations in men (P = 0.037). After adjustment for women's higher MPG, there was no statistically significant difference in MPG discrepancy between genders (P = 0.22). No significant interactions between MPG and aortic root diameter, relative wall thickness (RWT), heart rate, heart rhythm, cardiac output, and time interval between studies were found. In clinical practice, significant discrepancies in MPG were common when cath and Doppler are performed nonsimultaneously. No systematic bias was observed and Doppler results were as likely yield lower as higher MPGs than cath. EF difference was a significant predictor of discrepant MPG. Aortic root diameter, relative wall thickness, heart rate, heart rhythm, cardiac output, presence or severity of coronary artery disease, and time interval between studies were not predictors of discrepant results. [source]

    Representation of accuracy in the dorsal premotor cortex

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2000
    Jose E. Gomez
    Abstract The endpoint accuracy of a reaching movement strongly affects kinematics, particularly during the final phases of movement. However, where and how accuracy is represented in the central nervous system remains unknown. In this study, the discharge of 150 neurons located primarily in the dorsal premotor cortex (PMd), were recorded from monkeys performing an instructed delay, centre-out reaching task in which movement direction and target size were systematically varied. Linear regression analyses were used to assess the dependence of movement kinematics and cell discharge on target direction, size and tangential velocity (i.e. speed). The speed and timing of the movement were dependent on both direction and target size. Initially direction was the dominant predictor whilst target size became more important as the hand reached the target. A temporal multiple linear regression analysis found significant correlations with target size in 99 of 150 cells. The discharge of 134 cells was directionally tuned and 83 cells modulated with mean speed. Significant correlations of discharge with target size occurred throughout the task as did correlations with direction. However, correlations with direction preferentially occurred early in the task, prior to movement onset, whilst correlations with target size tended to occur late, well after movement onset. This temporal dependency of the firing in relationship to target direction and size mirrored that observed for the kinematics. We conclude that the discharge of PMd cells is highly correlated with the accuracy requirement of the movement. The timing of the correlations suggest that accuracy information is available for the planning and for the on-line control of endpoint accuracy. [source]

    A Method for Predicting Chloride Concentrations in Leachate at Natural Attenuation Landfills in the Precambrian Shield Regions of Ontario, Canada

    GROUND WATER MONITORING & REMEDIATION, Issue 3 2000
    Jim Gehrels
    Natural attenuation landfill sites continue to be the preferred method of domestic waste disposal in the Precambrian Shield regions of Ontario due to economic factors. The main challenge in siting these landfills is ensuring that there will be no adverse impact on off-site water resources. Impact risk assessments are generally based on estimated volumes and strengths of chloride in the leachate. While volumes can be estimated using simple water balances, peak chloride concentration predictions are based on judgment and are quite variable. Since design chloride strengths dictate the size of the required attenuation zone, overestimating concentrations will typically make it impossible to find a suitable site, while underestimating concentrations increases the potential for adverse off-site impacts occurring. Hydrogeological data from active and closed landfills in the Precambrian Shield region were collected to help develop a reliable method of predicting peak chloride concentrations in leachate. This study focused on 21 sites located on relatively permeable sandy soils since landfills underlain by low permeability clayey soils retain leachate similar to lined facilities. Linear regression analyses were conducted to determine if source chloride concentrations at the "sand" sites are significantly influenced by waste thickness, fill area, waste volume, waste deposition rate, hydraulic conductivity, upgradient flow length, depth to the water table, and moisture surplus. A strong relationship (R = 0.957) was found to exist between source chloride concentrations and waste volume. This empirical volume versus chloride regression equation can be used as the basis for establishing design chloride concentrations at new natural attenuation landfills developed over sandy soils in the Precambrian Shield regions of Ontario. An alternative risk assessment approach is required for sites developed over clay soils. [source]

    Cellular senescence in pretransplant renal biopsies predicts postoperative organ function

    AGING CELL, Issue 1 2009
    Liane M. McGlynn
    Summary Older and marginal donors have been used to meet the shortfall in available organs for renal transplantation. Post-transplant renal function and outcome from these donors are often poorer than chronologically younger donors. Some organs, however, function adequately for many years. We have hypothesized that such organs are biologically younger than poorer performing counterparts. We have tested this hypothesis in a cohort of pre-implantation human renal allograft biopsies (n = 75) that have been assayed by real-time polymerase chain reaction for the expression of known markers of cellular damage and biological aging, including CDKN2A, CDKN1A, SIRT2 and POT1. These have been investigated for any associations with traditional factors affecting transplant outcome (donor age, cold ischaemic time) and organ function post-transplant (serum creatinine levels). Linear regression analyses indicated a strong association for serum creatinine with pre-transplant CDKN2A levels (p = 0.001) and donor age (p = 0.004) at 6 months post-transplant. Both these markers correlated significantly with urinary protein to creatinine ratios (p = 0.002 and p = 0.005 respectively), an informative marker for subsequent graft dysfunction. POT1 expression also showed a significant association with this parameter (p = 0.05). Multiple linear regression analyses for CDKN2A and donor age accounted for 24.6% (p = 0.001) of observed variability in serum creatinine levels at 6 months and 23.7% (p = 0.001) at 1 year post-transplant. Thus, these data indicate that allograft biological age is an important novel prognostic determinant for renal transplant outcome. [source]

    Self-Esteem and Socioeconomic Disparities in Self-Perceived Oral Health

    JOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 1 2009
    David Locker
    Abstract Objective: To determine if psychosocial factors explain the socioeconomic disparities in self-perceived oral health that persist after controlling for oral status variables. Methods: Data came from the participants in the Canadian Community Health Survey 2003 who were residents in the city of Toronto. Oral health variables included self-rated oral health, a 13-item oral health scale, denture wearing, and having a tooth extracted in the previous year. The last two measures were regarded as proxy indicators of tooth loss. Psychosocial variables included a self-esteem scale, a depression scale, and single items measuring life satisfaction, life stress, and sense of cohesion. Socioeconomic status was assessed using total annual household income. Results: Interviews were completed with 2,754 dentate persons aged 20 years and over. Bivariate analyses confirmed that there were income gradients in self-rated oral health and scores on the oral health scale. Linear regression analyses confirmed that these persisted after controlling for age, gender, denture wearing, and having a tooth extracted in the previous year. In the model predicting self-rated oral health self-esteem, life satisfaction, stress, a sense of cohesion, and depression also contributed to the model, increased its explanatory power, and reduced the strength of but did not eliminate the association between income and self-rated oral health. Broadly, similar results were obtained when the oral health scale score was used as the dependent variable. In both analyses and all models, denture wearing had the strongest and most enduring effect. Conclusion: Psychosocial factors partly but do not wholly explain the socioeconomic disparities in self-perceived oral health in this population after controlling for tooth loss and denture wearing. Other variables need to be added to the models to increase their explanatory power. [source]

    Effect of Extended-Release Naltrexone (XR-NTX) on Quality of Life in Alcohol-Dependent Patients

    ALCOHOLISM, Issue 2 2009
    Helen M. Pettinati
    Background:, Extended-release naltrexone (XR-NTX) is a once-a-month injectable formulation for the treatment of alcohol dependence previously shown to reduce drinking and heavy drinking relative to placebo (Garbutt et al., 2005). A 24-week, randomized, double-blind, placebo-controlled study established the efficacy and safety of XR-NTX in this patient population. In this report, the effect of XR-NTX on quality of life (QOL) was examined. Methods:, Alcohol-dependent patients were randomly assigned to receive XR-NTX 380 mg (N = 205), XR-NTX 190 mg (N = 210), or placebo (N = 209), combined with a standardized psychosocial intervention. QOL was assessed using the Medical Outcomes Study 36-item short-form health survey, administered at baseline and at 4-week intervals during 24 weeks of treatment. Results:, Compared with U.S. population norms, patients showed initial impairment in the health-related QOL domains of mental health, social functioning, and problems with work or other daily activities due to emotional problems. Adherence to all 6 injections was 65% for XR-NTX 190 mg, 63% for XR-NTX 380 mg, and 64% for placebo. Generalized estimating equations analyses using an intention-to-treat sample revealed that XR-NTX 380 mg was associated with significantly greater improvements from baseline in mental health (p = 0.0496), social functioning (p = 0.010), general health (p = 0.048), and physical functioning (p = 0.028), compared with placebo. Linear regression analyses revealed that reductions from baseline in drinking (percentage of drinking days and percentage of heavy drinking days in the last 30 days) were significantly (p < 0.05) correlated with improvements in quality of life. Conclusion:, Extended-release naltrexone 380 mg in combination with psychosocial intervention was associated with improvements in QOL, specifically in the domains of mental health, social functioning, general health, and physical functioning. [source]

    Comparison of Principal Analysis and the Tucker3 Model

    MOLECULAR INFORMATICS, Issue 4 2003
    A Case Study
    Abstract A three-ways array data matrix consisting of the activity data of laccase enzyme has been evaluated by both principal component analyses (PCA) and Tucker3 model. Activity data have been determined in 28 culture media, at 6 sampling times and by four strains of Lentinus edodes. PCA has been carried out three times one of the factors being always the variables and the other two factors being the observations. The dimensionality of the matrices of loadings calculated by PCAs and those of component matrices of Tucker3 model has been reduced to two by the nonlinear mapping technique. It has been found that the dimensionality of component matrices for Tucker3 model can be predicted from the results of PCAs. Linear regression analyses indicated that the distribution of the original data points on the two-dimensional nonlinear maps considerably depends on the fact that the data have been calculated by PCA or by Tucker3 model. [source]

    Statistical Analysis of Surgical Dog-Ear Regression

    DERMATOLOGIC SURGERY, Issue 8 2008
    KYUNG SUK LEE MD
    BACKGROUND Several methods have been developed to prevent or correct dog-ears. Most of these methods, however, result in prolonged scars and operative times. OBJECTIVE We observed dog-ears without correction to examine the regression of dog-ears with time. METHODS The study was performed on 43 cases of dog-ears in 26 patients. Linear regression analysis was performed to examine the correlation between various factors and the height of the dog-ears (%). We produced a regression equation to allow prediction of the height of the dog-ears (%). In addition, we estimated the initial height of the dog-ears that should be removed during surgery. RESULTS The height of dog-ears regressed with time, and this response was better in younger and female patients. It was predicted that the time taken for a dog-ear to reduce to 50% of its original height was 20.697 days; the median time at which dog-ears completely regressed was 132 days. The odds of regression of dog-ears with an initial height of ,8 mm was 4.667 times greater than that of larger dog-ears. CONCLUSIONS If the height of a dog-ear is ,8 mm, we recommend observation rather than immediate surgical removal. [source]

    Comparison of Coronary Flow Velocities Between Patients with Obstructive and Nonobstructive Type Hypertrophic Cardiomyopathy: Noninvasive Assessment by Transthoracic Doppler Echocardiography

    ECHOCARDIOGRAPHY, Issue 1 2005
    Seden Celik M.D.
    Background: We aimed to compare coronary flow velocity (CFV) measurements of patients with nonobstructive (NHCM) and obstructive hypertrophic cardiomyopathy (HOCM) by using transthoracic Doppler echocardiography (TTDE). Methods and Results: In 11 patients with NHCM and 26 with HOCM, CFV in the distal left anterior descending (LAD) coronary was measured by TTDE (3.5 MHz) under the guidance of color Doppler flow mapping in addition to standard 2D and Doppler echocardiography. The results were compared with 24 normal participants who had no evidence of cardiac disease. Peak diastolic velocity of LAD was also higher in NHCM and HOCM than controls (52 ± 14 cm/sec and 54 ± 20 cm/sec vs 41 ± 11 cm/sec, respectively, P < 0.01). The analysis of systolic velocities revealed abnormal flow patterns in 16 (61%) patients with HOCM (12 systolic-reversal flow and 4 no systolic flow) and 6 (54%) (5 reversal flow and 1 zero flow) patients with NHCM (,11 ± 30 cm/sec and ,13 ± 38 cm/sec, vs 24 ± 9 cm/sec, respectively, P < 0.001). Linear regression analysis demonstrated no correlation between intraventricular pressure gradient and coronary flow velocities in HOCM patients. However, there were significant positive and negative correlations between septal thickness and diastolic and systolic velocities, respectively (r = 0.50, P < 0.002, and r =,0.43, P < 0.005). Conclusion: We conclude that the coronary flow velocity abnormalities are independent from the type of hypertrophic cardiomyopathy. [source]

    An analysis of cocaine powder in the Netherlands: content and health hazards due to adulterants

    ADDICTION, Issue 5 2009
    Tibor M. Brunt
    ABSTRACT Aims To report on trends in the content and adulterants present in street cocaine (powder) in the Netherlands and to describe the associated health hazards. Design and participants Drug consumers handed in samples of cocaine powder from 1999 to 2007 for analysis. Reports were compiled of users' experiences with the samples received. Measurements and analysis Linear regression analysis was used to assess the trend in adulterated cocaine powder across the study period, and comparison of reported adverse effects of adulterated with those of unadulterated cocaine by Fisher's exact test. Findings There has been a statistically significant upward trend in the occurrence of adulterated cocaine powder over the years. Adulterated cocaine was associated more frequently with reported adverse effects than unadulterated cocaine. Phenacetin, hydroxyzine and diltiazem appeared to be three adulterants contributing to these adverse effects. Conclusions An increase in adulterants was detected in the analysed cocaine powder between 1999 and 2007. This increase is associated with relatively more adverse effects with cocaine use. The cardiac and hallucinatory effects that were reported more frequently are not understood clearly. Adverse effects are likely to be due to several factors, including interactions of adulterants with cocaine and the route of administration. [source]

    Life table and heat tolerance of Acyrthosiphon pisum (Hemiptera: Aphididae) in subtropical Taiwan

    ENTOMOLOGICAL SCIENCE, Issue 3 2008
    Wei-Nung LU
    Abstract The effect of temperature on the life table of Acyrthosiphon pisum reared on Pisum sativum was evaluated under laboratory conditions using temperatures of 10, 15, 20, 25, 30, and 35°C. The development time of juvenile A. pisum decreased with increasing temperature (from 21.3 days at 10°C to 4.7 days at 35°C). Adult longevity also decreased with increasing temperature (from 53.2 days at 10°C to 2.3 days at 35°C). Interestingly, 70% and 25% of A. pisum nymphs reared at 30°C and 35°C, respectively, successfully developed into adults. These temperatures have previously been considered unsuitable for A. pisum development. However, adult aphids reared at 30°C and 35°C failed to reproduce. Linear regression analysis revealed that the lower development threshold of A. pisum was 153.1 degree-days above 1.9°C. Maximal average reproductive capability was observed at 10°C for A. pisum adults, with each adult producing more than 120 nymphs. The intrinsic rate of increase (rm) of A. pisum increased from 0.124/day at 10°C to 0.337/day at 25°C, whereas opposite trends were observed for the net reproductive rate (R0) and the mean generation time (GT). At 20°C and 25°C, the intrinsic rate of increase of A. pisum was significantly higher than at 10°C and 15°C (P < 0.0001), indicating that 20°C and 25°C are within the optimal range for the growth of A. pisum, and that 30°C is beyond the upper threshold limit for reproduction, which involves a temperature range that is narrower than that of the survival range (upper limit is unknown, but above 35°C). [source]

    Modelflow estimates of cardiac output compared with Doppler ultrasound during acute changes in vascular resistance in women

    EXPERIMENTAL PHYSIOLOGY, Issue 4 2010
    Kenneth S. Dyson
    We compared Modelflow (MF) estimates of cardiac stroke volume (SV) from the finger pressure-pulse waveform (Finometer®) with pulsed Doppler ultrasound (DU) of the ascending aorta during acute changes in total peripheral resistance (TPR) in the supine and head-up-tilt (HUT) postures. Twenty-four women were tested during intravenous infusion of 0.005 or 0.01 ,g kg,1 min,1 isoprenaline, 10 or 50 ng kg,1 min,1 noradrenaline and 0.3 mg sublingual nitroglycerine. Responses to static hand-grip exercise (SHG), graded lower body negative pressure (LBNP, from ,20 to ,45 mmHg) and 45 deg HUT were evaluated on separate days. Bland,Altman analysis indicated that SVMF yielded lower estimates than SVDU during infusion of 0.01 ,g kg,1 min,1 isoprenaline (SVMF 92.7 ± 15.5 versus SVDU 104.3 ± 22.9 ml, P= 0.03) and SHG (SVMF 78.8 ± 12.0 versus SVDU 106.1 ± 28.5 ml, P < 0.01), while larger estimates were recorded with SVMF during ,45 mmHg LBNP (SVMF 52.6 ± 10.7 versus SVDU 46.2 ± 14.5 ml, P= 0.04) and HUT (SVMF 59.3 ± 13.6 versus SVDU 45.2 ± 11.3 ml, P < 0.01). Linear regression analysis revealed a relationship (r2= 0.41, P < 0.01) between the change in TPR from baseline and the between-methods discrepancy in SV measurements. This relationship held up under all of the experimental protocols (regression for fixed effects, P= 0.46). These results revealed a discrepancy in MF estimates of SV, in comparison with those measured by DU, during acute changes in TPR. [source]

    Replication study of candidate genes for cognitive abilities: the Lothian Birth Cohort 1936

    GENES, BRAIN AND BEHAVIOR, Issue 2 2009
    L. M. Houlihan
    As the proportion of older people in societies has increased, research into the determinants of cognitive ageing has risen in importance. Genetic influences account for over 50% of the variance in adult cognitive abilities. Previous studies on cognition and illnesses with cognitive impairments have identified single nucleotide polymorphisms (SNPs) within candidate genes that might influence cognition or age-related cognitive change. This study investigated 10 candidate genes in over 1000 Scots: the Lothian Birth Cohort 1936 (LBC1936). These participants were tested on general cognitive ability (Scottish Mental Survey 1947) at age 11. At mean age 70, they completed the same general cognitive ability test and a battery of diverse cognitive tests. Nineteen SNPs in 10 genes previously associated with cognition, Alzheimer's disease or autism were genotyped in 1063 individuals. The genes include BDNF, COMT, DISC1, KL, NCSTN, PPP1R1B, PRNP, SHANK3, SORL1 and WRN. Linear regression analysis investigated the additive effect of each SNP on the cognitive variables, covarying for gender and age. Childhood cognitive ability was also included as a covariate to identify associations specifically with cognitive ageing. Certain SNPs reached the conventional significance threshold for association with cognitive traits or cognitive ageing in LBC1936 (P < 0.05). No SNPs reached the Bonferroni-level of significance (all P > 0.0015). Of the 10 genes, we discuss that COMT, KL, PRNP, PPP1R1B, SORL1 and WRN especially merit further attention for association with cognitive ability and/or age-related cognitive change. All results are also presented so that they are valuable for future meta-analyses of candidate genes for cognition. [source]

    Comparison of the MMSE and RUDAS cognitive screening tools in an elderly inpatient population in everyday clinical use

    INTERNAL MEDICINE JOURNAL, Issue 6 2009
    J. Pang
    Abstract We compared test score and performance times of Folstein's Mini Mental State Examination (MMSE) and the Rowland Universal Dementia Assessment Scale (RUDAS). Forty-six patients were recruited. The mean score was 20.6 for the MMSE and 20.5 for the RUDAS. Linear regression analysis revealed an r value of 0.83 (P < 0.05). The mean performance time was 9.4 min for both the MMSE and the RUDAS. Patient satisfaction was similar for both tests. Surveyed clinicians preferred the MMSE because of greater familiarity. We concluded that the RUDAS correlates well with the MMSE and is no more time-consuming to perform. It has good clinical utility as a cognitive screening tool. [source]

    Radiographic lung density assessed by computed tomography is associated with extravascular lung water content

    ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2010
    V. V. KUZKOV
    Background: We hypothesized that in acute lung injury (ALI), the volume of pulmonary tissue with aqueous density, as determined by spiral computed tomography (CT), is associated with extravascular lung water content. Our aim was to compare tissue volume index, as assessed by CT, before and after oleic acid-induced ALI, with extravascular lung water indexes (EVLWI), determined with single transpulmonary thermodilution (EVLWISTD), thermal-dye dilution (EVLWITDD), and postmortem gravimetry (EVLWIG). Methods: Seven instrumented sheep received an intravenous infusion of oleic acid 0.08 ml/kg (OA group) and four animals had vehicle only (Control group). The day before, and immediately after the experiment, sheep were anesthetized to undergo quantitative CT examinations during a short breath hold. Hemodynamics, oxygenation, EVLWISTD, and EVLWTDD were registered. Linear regression analysis was used to assess the relationships between EVLWISTD, EVLWTDD, EVLWIG, and lung tissue volume index (TVICT) determined with CT. Results: In the OA group, total lung volume increased compared with Controls. Poorly and non-aerated lung volumes increased a 3.6- and 4.9-fold, respectively, and TVICT almost doubled. EVLWISTD, EVLWITDD, and TVICT were associated significantly with EVLWIG (r=0.85, 0.90, and 0.88, respectively; P<0.001). TVICT deviated from the reference EVLWIG values to the greatest extent with a mean bias ± 2SD of 4.0 ± 6.0 ml/kg. Conclusions: In ovine oleic acid-induced ALI, lung tissue volume, as assessed by quantitative CT, is in close agreement with EVLWI, as determined by indicator dilution methods and postmortem gravimetry, but overestimates lung fluid content. [source]

    Pleth variability index predicts hypotension during anesthesia induction

    ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2010
    M. TSUCHIYA
    Background: The pleth variability index (PVI) is a new algorithm used for automatic estimation of respiratory variations in pulse oximeter waveform amplitude, which might predict fluid responsiveness. Because anesthesia-induced hypotension may be partly related to patient volume status, we speculated that pre-anesthesia PVI would be able to identify high-risk patients for significant blood pressure decrease during anesthesia induction. Methods: We measured the PVI, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) in 76 adult healthy patients under light sedation with fentanyl to obtain pre-anesthesia control values. Anesthesia was induced with bolus administrations of 1.8 mg/kg propofol and 0.6 mg/kg rocuronium. During the 3-min period from the start of propofol administration, HR, SBP, DBP, and MAP were measured at 30-s intervals. Results: HR, SBP, DBP, and MAP were significantly decreased after propofol administration by 8.5%, 33%, 23%, and 26%, respectively, as compared with the pre-anesthesia control values. Linear regression analysis that compared pre-anesthesia PVI with the decrease in MAP yielded an r value of ,0.73. Decreases in SBP and DBP were moderately correlated with pre-anesthesia PVI, while HR was not. By classifying PVI >15 as positive, a MAP decrease >25 mmHg could be predicted, with sensitivity, specificity, positive predictive, and negative predictive values of 0.79, 0.71, 0.73, and 0.77, respectively. Conclusion: Pre-anesthesia PVI can predict a decrease in MAP during anesthesia induction with propofol. Its measurement may be useful to identify high-risk patients for developing severe hypotension during anesthesia induction. [source]

    Are Elderly Hospitalized Patients Getting Enough Protein?

    JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 6 2008
    Cathy Gaillard MSc
    OBJECTIVES: To determine the protein requirements of elderly hospitalized patients. DESIGN: Cross-sectional evaluation of nitrogen balance. SETTING: Short-stay geriatric ward or rehabilitation care unit. PARTICIPANTS: Thirty-six elderly hospitalized patients (aged 65,99) admitted to short-stay and rehabilitation care units. MEASUREMENTS: Resting energy expenditure and nitrogen balance were determined under usual and spontaneous energy and protein intake after subjects were clinically stable (3,5 days after admission). All items consumed over a 3-day period were weighed to determine energy and protein intake. RESULTS: Energy (23.5±6.3 kcal/kg per day) and protein (0.99±0.24 g/kg per day) intake were similar in men and women, and nitrogen balance was neutral (0.37±2.6 g/day; P=.41 vs a neutral nitrogen balance, i.e., 0 g/d). Half of the patients had a positive nitrogen balance. Plasma C-reactive protein, renal function, nutritional status, and initial diagnosis had no influence on nitrogen balance. In contrast, energy and protein intakes correlated positively with nitrogen balance. Linear regression analysis suggested that an elderly hospitalized patient with an energy intake of 1.31 times resting energy expenditure or greater appears to require a minimum protein intake of 1.06±0.28 g/kg per day. CONCLUSION: Mean protein intake to reach a neutral nitrogen balance in elderly hospitalized patients is 1.06±0.28 g/kg per day, which is higher than current recommendations for healthy elderly people. Safe protein intake (that would be adequate to ensure that 95% of patients remain in positive nitrogen balance) is difficult to establish. [source]

    Correlation between the Individual and the Combined Width of the Six Maxillary Anterior Teeth

    JOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 3 2009
    LUIZ CARLOS GONÇALVES DMD
    ABSTRACT Purpose:, There is a consensus in the community of dental research that the selection of undersized artificial maxillary anterior teeth offers an unnatural appearance to the denture. Several methods to select the adequate width of these teeth are of questionable validity, and many dentures have an obviously artificial appearance. This article assessed the relationship between the individual and the combined width of maxillary anterior teeth. Materials and Methods:, Impressions were made of the anterior dentition of 69 dentate undergraduate students with rubber impression silicon, and casts were formed. The individual widths of the maxillary anterior teeth were measured by using a digital caliper (SC-6 digital caliper, Mitutoyo Corporation, Tokyo, Japan), and the combined width was registered by both adding the individual width and using a flexible millimeter ruler. Results:, Student's t -test showed significant differences between the analogous teeth and different sides of the maxillary dental arch (p = 0.001), with the exception of the central incisor (p = 0.984). Pearson's product moment correlation coefficient showed significant positive correlation between all the measurements compared (p = 0.000). Linear regression analysis concluded three mathematical equations to obtain the individual tooth width after measuring the combined width of the six maxillary anterior teeth by using a flexible millimeter ruler. Conclusions:, The individual tooth width can be determined if the combined width of the maxillary anterior teeth is obtained by using a flexible millimeter ruler. CLINICAL SIGNIFICANCE The adequate selection of each maxillary anterior tooth width can offer variance and individuality to the denture, particularly for partially dentate patients. By offering an adequate tooth-to-tooth relationship, the esthetic result of the oral rehabilitation treatment can be improved. [source]

    Effect of Heat Treatment on Antioxidant Capacity and Flavor Volatiles of Mead

    JOURNAL OF FOOD SCIENCE, Issue 2 2005
    Carol L. Wintersteen
    ABSTRACT: The objective of this study was to evaluate the effects of heat processing on the antioxidant capacity of mead (honey wine). Soy and buckwheat honey musts were subjected to 2 heat treatments and fermented into wine. Total phenolic concentration was determined. High-performance liquid chromatography (HPLC) phenolic profiling was performed on the methanol fraction of Amberlite extraction. Antioxidant capacity was evaluated using the oxygen radical absorbance capacity (ORAC) assay. Changes in volatile components were evaluated by headspace-solid phase microextraction/gas chromatography-mass spectrometry (H-SPME/GC-MS). ORAC values of experimental meads (3.62 mMTrolox equivalent) were comparable to those of commercial white wine (3.66 mMTrolox equivalent). No significant difference in antioxidant capacity due to heat treatment or honey type was observed. There was no difference in total phenolics between heat treatments in buckwheat mead; however, soy mead made from high-heated must had significantly greater phenolic concentration than the gently heated mead (,= 0.05). Linear regression analysis indicated a strong positive correlation between total phenolic concentration and antioxidant capacity by ORAC (r= 0.9077; P < 0.0001). HPLC analysis of phenolic profiles in the methanol fractions of Amberlite extraction of the meads indicated significantly higher levels of certain phenolics as a result of the high-heat process in buckwheat mead, but not in soy mead. Differences in volatile components that potentially impact flavor were noted between high and low heat treatments. Results of this study suggest dramatic heat treatments that are often avoided because their flavor impact in mead production have the potential to alter the antioxidant capacity of mead by changing phenolic profiles. [source]

    In healthy subjects without knee osteoarthritis, the peak knee adduction moment influences the acute effect of shoe interventions designed to reduce medial compartment knee load

    JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2007
    David S. Fisher
    Abstract The purpose of this study was to evaluate shoe sole material stiffness changes and angle changes that are intended to reduce the peak knee adduction moment during walking. Fourteen physically active adults were tested wearing their personal shoes (control) and five intervention pairs, two with stiffness variations, two with angle variations, and a placebo shoe. The intervention shoes were evaluated based on how much they reduced the peak knee adduction moment compared to the control shoe. An ANOVA test was used to detect differences between interventions. Linear regression analysis was used to determine a relationship between the magnitude of the knee adduction moment prior to intervention and the effectiveness of the intervention in reducing the peak knee adduction moment. Peak knee adduction moments were reduced for the altered stiffness and altered angle shoes (p,<,0.010), but not for the placebo shoe (p,=,0.363). Additionally, linear regression analysis showed that subjects with higher knee adduction moments prior to intervention had larger reductions in the peak knee adduction moment (p,<,0.010). These results demonstrate that shoe sole stiffness and angle interventions can be used to reduce the peak knee adduction moment and that subjects with initially higher peak knee adduction moments have higher reductions in their peak knee adduction moments. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:540,546, 2007 [source]

    Effect of bone chip orientation on quantitative estimates of changes in bone mass using digital subtraction radiography

    JOURNAL OF PERIODONTAL RESEARCH, Issue 3 2003
    André Mol
    Objectives:, To assess the effect of the orientation of arbitrarily shaped bone chips on the correlation between radiographic estimates of bone loss and true mineral loss using digital subtraction radiography. Methods:, Twenty arbitrarily shaped bone chips (dry weight 1,10 mg) were placed individually on the superior lingual aspect of the interdental alveolar bone of a dry dentate hemi-mandible. After acquiring the first baseline image, each chip was rotated 90 degrees and a second radiograph was captured. Follow-up images were created without the bone chips and after rotating the mandible 0, 1, 2, 4, and 6 degrees around a vertical axis. Aluminum step tablet intensities were used to normalize image intensities for each image pair. Follow-up images were registered and geometrically standardized using projective standardization. Bone chips were dry ashed and analyzed for calcium content using atomic absorption. Results:, No significant difference was found between the radiographic estimates of bone loss from the different bone chip orientations (Wilcoxon: P > 0.05). The correlation between the two series of estimates for all rotations was 0.93 (Spearman: P < 0.05). Linear regression analysis indicated that both correlates did not differ appreciably ( and ). Conclusion:, It is concluded that the spatial orientation of arbitrarily shaped bone chips does not have a significant impact on quantitative estimates of changes in bone mass in digital subtraction radiography. These results were obtained in the presence of irreversible projection errors of up to six degrees and after application of projective standardization for image reconstruction and image registration. [source]

    In-vitro permeation of drugs into porcine hair follicles: is it quantitatively equivalent to permeation into human hair follicles?

    JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2008
    Yakov Frum
    It is already well-established that the general permeability properties of porcine skin are close to those of human skin. However, very little is known with respect to drug absorption into hair follicles and the similarities if any between the two types of tissue. The aim of this study was to use the skin sandwich system to quantify follicular drug absorption into porcine hair follicles. To our knowledge, this is the first time that the skin sandwich has been extended to porcine tissue. For this purpose, seven different drugs , estradiol, corticosterone, hydrocortisone, aldosterone, cimetidine, deoxyadenosine and adenosine , exhibiting a wide range of log octanol-water partition coefficients (log Ko/w), but comparable molecular weights, were chosen as candidate solutes. The results showed a parabolic profile with maximal follicular contribution occurring at intermediate log Ko/w values. Linear regression analysis indicated that the follicular contributions in porcine skin correlated well with previously published follicular contributions in human skin (r2 = 0.87). The novelty of this research is that we show that porcine tissue is a good surrogate for modelling human skin permeability within the specific context of quantifying drug absorption into hair follicles. [source]

    USE OF LITHIUM DILUTION AND PULSE CONTOUR ANALYSIS CARDIAC OUTPUT DETERMINATION IN ANAESTHETISED HORSES , A CLINICAL EVALUATION

    JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue S1 2004
    Gayle D Hallowell
    Pulse contour analysis is a relatively new method of continuously monitoring cardiac output. The objective of this study was to evaluate the suitability of the human algorithm for calculation of continuous cardiac output from the pulse waveform, for use in anaesthetised horses. Cardiac output was measured in 27 anaesthetised clinical cases comparing lithium dilution (LiDCO) with a preceding, calibrated cardiac output measured from the pulse waveform (PulseCO) using a commercial system (LiDCOplus, LiDCO Ltd., Cambridge, UK). These comparisons were repeated every 20,30 min. Positive inotropes or vasopressors were administered when clinically indicated. Cardiac output values obtained ranged from 15.2,52.2 L/min, with cardiac indices from 30.7,114.9 ml/kg/min. Eighty-nine comparisons were obtained. The mean bias was 0.24 ml/kg/min +/,6.48 ml/kg/min. The limits of agreement were ,12.72,13.2 ml/kg/min. The 95% confidence interval for the upper limit of agreement was 12.07,14.33 ml/kg/min and for the lower limit of agreement was ,11.59,13.85 ml/kg/min. Linear regression analysis demonstrated a correlation coefficient (r2) of 0.89 and produced an equation of PulseCO (mls kg,1 minute,1)=0.9226LiDCO (mls kg,1minute,1) +5.354. This method of pulse contour analysis is a relatively non-invasive and reliable way of monitoring continuous cardiac output in the horse under anaesthesia. The ability to easily continuously monitor cardiac output may improve morbidity and mortality in the anaesthetised horse. [source]

    Validation of limited sampling strategy for the estimation of mycophenolic acid exposure in Chinese adult liver transplant recipients

    LIVER TRANSPLANTATION, Issue 12 2007
    Chen Hao
    Mycophenolate mofetil (MMF) is indicated as immunosuppressive therapy in liver transplantation. The abbreviated models for the estimation of mycophenolic acid (MPA) area under the concentration-time curve (AUC) have been established by limited sampling strategies (LSSs) in adult liver transplant recipients. In the current study, the performance of the abbreviated models to predict MPA exposure was validated in an independent group of patients. A total of 30 MPA pharmacokinetic profiles from 30 liver transplant recipients receiving MMF in combination with tacrolimus were used to compare 8 models' performance with a full 10 time-point MPA-AUC. Linear regression analysis and Bland-Altman analysis were used to compare the estimated MPA-AUC0-12h from each model against the measured MPA-AUC0-12h. A wide range of agreement was shown when estimated MPA-AUC0-12h was compared with measured MPA-AUC0-12h, and the range of coefficient of determination (r2) was from 0.479 to 0.936. The model based on MPA pharmacokinetic parameters C1h, C2h, C6h, and C8h had the best ability to predict measured MPA-AUC0-12h, with the best coefficient of determination (r2 = 0.936), the excellent prediction bias (2.18%), the best prediction precision (5.11%), and the best prediction variation (2SD = ±7.88 mg · h/L). However, the model based on MPA pharmacokinetic sampling time points C1h, C2h, and C4h was more suitable when concerned with clinical convenience, which had shorter sampling interval, an excellent coefficient of determination (r2 = 0.795), an excellent prediction bias (3.48%), an acceptable prediction precision (14.37%), and a good prediction variation (2SD = ±13.23 mg · h/L). Measured MPA-AUC0-12h could be best predicted by using MPA pharmacokinetic parameters C1h, C2h, C6h, and C8h. The model based on MPA pharmacokinetic parameters C1h, C2h, and C4h was more feasible in clinical application. Liver Transpl 13:1684,1693, 2007. © 2007 AASLD. [source]

    Computation and analysis of 19F substituent chemical shifts of some bridgehead-substituted polycyclic alkyl fluorides

    MAGNETIC RESONANCE IN CHEMISTRY, Issue 7 2003
    William Adcock
    Abstract The 19F NMR shieldings for several remotely substituted rigid polycyclic alkyl fluorides with common sets of substituents covering a wide range of electronic effects were calculated using the DFT-GIAO theoretical model. The level of theory, B3LYP/6,311+G(2d,p), was chosen based on trial calculations which gave good agreement with experimental values where known. The optimized geometries were used to obtain various molecular parameters (fluorine natural charges, electron occupancies on fluorine of lone pairs and of the CF bond, and hybridization states) by means of natural bond orbital (NBO) analysis which could help in understanding electronic transmission mechanisms underlying 19F substituent chemical shifts (SCS) in these systems. Linear regression analysis was employed to explore the relationship between the calculated 19F SCS and polar substituent constants and also the NBO derived molecular parameters. The 19F SCS are best described by an electronegativity parameter. The most pertinent molecular parameters appear to be the occupation number of the NBO p-type fluorine lone pair and the occupation number of the CF antibonding orbital. This trend suggests that in these types of rigid saturated systems hyperconjugative interactions play a key role in determining the 19F SCS. Electrostatic field effects appear to be relatively unimportant. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    The feasibility and reliability of using circular electrode for sphincter of Oddi electromyography in anaesthetised rabbits

    NEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2009
    F. Chen
    Abstract, Sphincter of Oddi manometry (SOM) is the gold standard for assessing sphincter of Oddi dysfunction (SOD), but is considered a diagnostic sensitivity of 30,80% and associated with significant complications of pancreatitis. Electromyography (EMG) of sphincter of Oddi (SO) using a circular electrode (CE) may be useful in improving diagnostic accuracy and reducing complications. To evaluate the feasibility and reliability of the CE, we record myoelectric activity of SO in rabbits using the CE to compare with the traditional needle electrode (NE). The CE was prepared using a double-channel biogel catheter with two silver rings at the head of the catheter. The CE was then inserted into the lumen of the SO through the duodenal papilla, and myoelectric activity was recorded in the SO in 30 rabbits. An EMG recorded using an NE was performed at the same time, when the SO was in basal state, after injection of cholecystokinin and N-butylscopolamine bromide. Electromyographs recorded by the two methods were then evaluated. Satisfactory SO EMGs were acquired using the CE without any injury. Simultaneous recording revealed a very similar traces and one-to-one correspondence of SO spike bursts (SOSB). Linear regression analysis showed a significant direct correlation between the two methods for SOSB duration and amplitude. The results suggested that CE was comparable with NE in terms of recording efficacy. The CE also has advantages of easy fixation, accurate localisation, broad applicability and ease of achieving satisfactory outcomes without trauma, compared with the NE. [source]

    Refractive error and ocular biometry in Jordanian adults

    OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 4 2005
    Edward A. H. Mallen
    Abstract The aim of this study was to establish the prevalence of refractive errors in Jordanian adults of working age, and to study the ocular biometric correlates of refractive error in this population. Refractive error and ocular biometry were measured in 1093 Jordanian adult subjects aged 17,40 years to determine the prevalence of refractive error, and explore structural correlations of ametropia. Refractive error was measured using a Grand-Seiko GR-3100K closed-view infrared autorefractor. Ocular component measurements were made using A-scan ultrasonography and autokeratometry. The prevalence of myopia [spherical equivalent refraction (SER) less than ,0.50 DS] and hyperopia (SER greater than +0.50 DS) was 53.71 and 5.67% respectively; 40.62% of the sample was emmetropic (refraction between +0.50 D and ,0.50 D inclusive in both principal meridians). The distribution of SER was found to show marked leptokurtosis, exhibiting a peak between plano and 1 D of myopia. Corneal radius, anterior chamber depth, crystalline lens thickness, vitreous chamber depth and axial length (AL) parameters were normally distributed in the population studied. AL to corneal curvature ratio was not normally distributed, and showed marked leptokurtosis. Linear regression analysis showed that AL correlated most closely with spherical equivalent refractive error. This study has established a database of refractive error prevalence and ocular biometric correlates of ametropia in a Middle Eastern population of working age. [source]

    Comparison of different near-infrared spectroscopic cerebral oxygenation indices with central venous and jugular venous oxygenation saturation in children

    PEDIATRIC ANESTHESIA, Issue 2 2008
    NICOLE NAGDYMAN
    Summary Background:, We compared two different near-infrared spectrophotometers: cerebral tissue oxygenation index (TOI) measured by NIRO 200 and regional cerebral oxygenation index (rSO2) measured by INVOS 5100 with venous oxygen saturation in the jugular bulb (SjO2) and central SvO2 from the superior caval vein (SVC) during elective cardiac catheterization in children. Methods:, A prospective observational clinical study in 31 children with congenital heart defects in a catheterization laboratory was undertaken. TOI was compared with SjO2 in the left jugular bulb and with SvO2. rSO2 was compared with SjO2 from the right jugular bulb and SvO2. Linear regression analysis and Pearson's correlation coefficient were calculated and Bland,Altman analyses were performed. Results:, Cerebral TOI and SjO2 were significantly correlated (r = 0.56, P < 0.0001), as well as TOI and SvO2 with r = 0.74 (P < 0.0001). Bland,Altman plots showed a mean bias of ,4.3% with limits of agreement of 15.7% and ,24.3% for TOI and SjO2 and a mean bias of ,4.9% with limits of agreement of 10.3% and ,20.1% for TOI and SvO2. Cerebral rSO2 and SjO2 showed a significant correlation (r = 0.83, P < 0.0001) and rSO2 and SvO2 showed excellent correlation with r = 0.93 (P < 0.0001). Bland,Altman plots showed a mean bias of ,5.2% with limits of agreement of between 8.4% and ,18.8% for rSO2 and SjO2 and a mean bias of 5.6% with limits of agreement of 13.4% and ,2.2% for rSO2 and SvO2. Conclusions:, Both near-infrared spectroscopy devices demonstrate a significant correlation with SjO2 and SvO2 values; nevertheless both devices demonstrate a substantial bias of the measurements to both SjO2 and SvO2. [source]