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PubMed2005

Calculation of spin-densities within the context of density functional theory. The crucial role of the correlation functional.

It is demonstrated that the LYP correlation functional is not suited to be used for the calculation of electron spin resonance hyperfine structure (HFS) constants, nuclear magnetic resonance spin-spin coupling constants, magnetic, shieldings and other properties that require a balanced account of opposite- and equal-spin correlation, especially in the core region. In the case of the HFS constants of alkali atoms, LYP exaggerates opposite-spin correlation effects thus invoking too strong in-out correlation effects, an exaggerated spin-polarization pattern in the core shells of the atoms, and, consequently, too large HFS constants. Any correlation functional that provides a balanced account of opposite- and equal-spin correlation leads to improved HFS constants, which is proven by comparing results obtained with the LYP and the PW91 correlation functional. It is suggested that specific response properties are calculated with the PW91 rather than the LYP correlation functional.

Journal Article↗

PubMed1996

Hemodynamic alterations in focal cerebral ischemia: temporal correlation analysis for functional imaging.

We describe a novel approach for analysing the hemodynamic alterations that result after focal cerebral ischemia. This approach utilizes a temporal correlation analysis of first pass transit data obtained with functional imaging. First pass transits of injected contrast agents are measured with dynamic CT scanning. Normal transit profiles are obtained from contralateral cortical regions to serve as reference profiles. Normalized correlations are then calculated to compare transit profiles from each individual pixel within the brain to the normal reference profile. The normalized correlation coefficient is used as a measure of temporal similarity to quantitatively assess deviations from normal hemodynamics. The method is based on the premise that perturbed hemodynamics are manifested as changes in the shape of the cerebral transit profiles. Correlation maps are produced that display regional alterations in cerebral hemodynamics. Results from rabbit (n=4) and rat (n=4) models of focal ischemia are presented. In the normal contralateral hemisphere, correlation values range from 0.83-0.93 with coefficients of variation of less than 3-4% . The ischemic core is comprised of regions without significant bolus transit. The peripheral zones that lie between normal brain and the ischemic core are composed of intermediate correlation values. By setting statistical thresholds (mean minus 2SD, p < 0.05), we quantitatively define these intermediate zones as the hemodynamic penumbra, i.e. regions where the shape of the first pass transit profile has been altered. The resulting correlation maps clearly image gradients of altered cerebral hemodynamics. Perfusion indices calculated based on transit profile peaks revealed that the penumbral zones possess reduced perfusion on the order of about 40 percent of contralateral values. In summary, we believe that temporal correlation analysis of first pass transit profiles can be used to image the hemodynamic penumbra in focal cerebral ischemia.

Animals↗

PubMed1999

Correlation between serial changes in left-sided heart chambers and atrial natriuretic peptide and N-terminal pro atrial natriuretic peptide after a first myocardial infarction. An echocardiographic study.

Dilatation of the left ventricle predicts morbidity and mortality after acute myocardial infarction. We compared serial echocardiographic examinations of the left atrium and ventricle with measurements of plasma atrial natriuretic peptide (ANP) and plasma N-terminal pro atrial natriuretic peptide (NT-proANP) in 22 patients during the first 6 months following a first myocardial infarction. ANP, but not NT-proANP, was found to be significantly correlated to the diastolic/systolic size of the left atrium (r = 0.58/0.60) and the systolic size of the left ventricle (r = 0.43) in the acute phase 2-4 days after infarction. At 10-12 days after the infarction, we found a significant correlation between all sizes of the left-sided chambers and ANP, whereas NT-proANP only correlated with the left atrial sizes. Three months after the infarction, all sizes of the left-sided chambers correlated with both ANP and NT-proANP, with the exception of a non-significant correlation between NT-proANP and the left atrial diastolic size. After 6 months only the area of the diastolic and systolic left atrium correlated with plasma ANP and only the systolic size of the left atrium correlated with NT-proANP. The percentage change in the size of the left atrium, but not the left ventricle, correlated significantly with the percentage change in both ANP (r = 0.57) and NT-proANP (r = 0.70). We conclude that the distension of the left atrium rather than the dilatation of the left ventricle is related to the concentration of ANP and NT-proANP after an acute myocardial infarction.

Adult↗

PubMed2005

Correlation between visual examination of the cervix and digital examination.

OBJECTIVE: To determine the correlation between visual assessment of the cervix and digital examination. METHODS: Prospective study of patients presenting to Labor and Delivery. Exclusion criteria were preterm premature ruptured membranes (PPROM) and placenta previa. Visual and digital assessments of cervical dilation, effacement, position, and station of fetal presenting part were made. Correlation between visual and digital examinations was measured using Spearman rank correlation coefficient (COR). A p-value<0.05 was considered significant. RESULTS: The study involved a total of 107 patients at a mean gestational age of 32.3 weeks (range 17-41). Seven patients had ruptured membranes, and 46 were nulliparous. Visual assessment correlated with digital examination for all parameters measured with Spearman rank correlation coefficients between 0.618 and 0.686 (all significant at p<0.001). Correlations between visual and digital assessment of cervical dilation, effacement, station, and position were not as strong (0.291-0.699), but remained significant (p<0.02) in a subgroup of 50 preterm patients<34 weeks gestation. CONCLUSION: Visual assessment correlates with digital examination of the cervix. This correlation remained significant in a subset of preterm patients with intact membranes.

Cervix Uteri↗

PubMed2004

Correlation between serum leptin levels and insulin sensitivity in diffuse toxic goiter.

OBJECTIVE: The aim of this survey was to assess the correlation between leptin and insulin sensitivity (IS) in cases of diffuse toxic goiter. DESIGN, PATIENTS, MEASUREMENTS: This is a descriptive study on patients with diffuse toxic goiter (DTG) assessing their body mass index (BMI), serum leptin concentrations, circulating insulin (area under the curve (AuC) of insulin), average insulin level, thyroid hormones, thyroid stimulating hormone (TSH), glycemia and IS (using a hyperinsulinemic-euglycemic clamp and the homeostasis model for assessment of insulin resistance (HOMA-IR) before and after euthyroidism induced with metimazol. RESULTS: The average patient age was 35 years old (range 31-40 years), height was 157 cm (range 151-160 cm), glycemia was 4.3 +/- 0.3 mmol/L and TSH 0.1 +/- 0.1 microU/mL. Average leptin level was 11.3 +/- 2.8 ng/dL, the average insulin level was 10.13 +/- 3.7 mIU/mL and the AuC for insulin was 50.6 +/- 18 microIU x min/mL. No correlation was found between leptin and BMI, thyroid hormones and glycemia. While controlling for the BMI effect, a correlation was found between leptin and TSH (r = -0.77, p = 0.042), as well as between leptin and insulinemia (r = 0.93, r2 = 0.86, p = 0.001) independently from the state of thyroid function. There was a tendency for a high correlation between leptin and the insulin AuC (hyperthyroidism: r = 0.89, p = 0.056; euthyroidism: r = 0.99, p = 0.056). A negative correlation was found between IS and the insulin AuC (rho = -0.58, p = 0.18). There was a high tendency for correlation between leptin and IS when the BMI effect (HOMA-IR: r = 0.70, p = 0.12; PHE: r = -0.55, p = 0.26) was taken into consideration. CONCLUSIONS: There is a high tendency for a negative correlation between leptin and IS when the BMI effect is controlled. There is a high tendency for a positive correlation between leptin and insulin and TSH.

Adult↗

PubMed2003

Correlation of platelet count changes with liver cell destruction in HELLP syndrome.

OBJECTIVE: HELLP syndrome is defined as a subset of preeclampsia involving a combination of hemolysis, low platelets affecting the circulatory system, and elevated liver enzymes, reflecting liver cell destruction. Our objective was to assess the correlation between the platelet count changes and liver cell destruction as indicated by aspartate aminotransferase (AST) levels. METHOD: We reviewed the records of 15 preeclamptic patients who developed HELLP syndrome as defined by 1) hemolysis, 2) elevated liver enzymes with an AST greater than 70 U/L (>2 SD above mean), and 3) low platelets (<100x10(9)/L). In these patients, both platelet counts and AST were assessed every 4-6 hr before and after delivery until recovery. At least eight laboratory assessments were done on each patient and were available for review. In each patient, the correlation between platelet count and AST levels was done using the Spearman rank order correlation coefficient. RESULTS: A negative correlation was found between platelet count and AST levels. A correlation coefficient of greater than 0.8 occurred in 53% of cases. The correlation coefficient ranged from 0.1 to 0.93. In all cases, improvement of liver cell dysfunction occurred within 4 hr of recovery of platelet count. At 72 hr postpartum, 73% of the platelet counts had not recovered to >150x10(9)/L, and 66% of patients with abnormally elevated AST levels had not returned to <35 U/L. CONCLUSIONS: Liver dysfunction and platelet count are poorly correlated in individual cases. This lack of correlation is evident both during decline and recovery of the platelet counts. Changes in platelet count cannot be used as a proxy for liver dysfunction in severe preeclampsia with HELLP syndrome.

Adult↗

PubMed1993

Spatial and space-time correlations in systems of subpopulations with genetic drift and migration.

The geographic distribution of genetic variation is an important theoretical and experimental component of population genetics. Previous characterizations of genetic structure of populations have used measures of spatial variance and spatial correlations. Yet a full understanding of the causes and consequences of spatial structure requires complete characterization of the underlying space-time system. This paper examines important interactions between processes and spatial structure in systems of subpopulations with migration and drift, by analyzing correlations of gene frequencies over space and time. We develop methods for studying important features of the complete set of space-time correlations of gene frequencies for the first time in population genetics. These methods also provide a new alternative for studying the purely spatial correlations and the variance, for models with general spatial dimensionalities and migration patterns. These results are obtained by employing theorems, previously unused in population genetics, for space-time autoregressive (STAR) stochastic spatial time series. We include results on systems with subpopulation interactions that have time delay lags (temporal orders) greater than one. We use the space-time correlation structure to develop novel estimators for migration rates that are based on space-time data (samples collected over space and time) rather than on purely spatial data, for real systems. We examine the space-time and spatial correlations for some specific stepping stone migration models. One focus is on the effects of anisotropic migration rates. Partial space-time correlation coefficients can be used for identifying migration patterns. Using STAR models, the spatial, space-time, and partial space-time correlations together provide a framework with an unprecedented level of detail for characterizing, predicting and contrasting space-time theoretical distributions of gene frequencies, and for identifying features such as the pattern of migration and estimating migration rates in experimental studies of genetic variation over space and time.

Biometry↗

PubMed1994

Allozyme and RFLP heterozygosities as correlates of growth rate in the scallop Placopecten magellanicus: a test of the associative overdominance hypothesis.

Several studies have reported positive correlations between the degree of enzyme heterozygosity and fitness-related traits. Notable among these are the correlations between heterozygosity and growth rate in marine bivalves. Whether the correlation is the result of intrinsic functional differences between enzyme variants at the electrophoretic loci scored or arises from non-random genotypic associations between these loci and others segregating for deleterious recessive genes (the associative overdominance hypothesis) is a matter of continuing debate. A prediction of the associative overdominance hypothesis, not shared by explanations that treat the enzyme loci as causative agents of the correlation, is that the correlation is not specific to the type of genetic marker used. We have tested this prediction by scoring heterozygosity at single locus nuclear restriction fragment length polymorphisms (RFLPs) in a cohort of juvenile scallops (Placopecten magellanicus) in which growth rate was known to be positively correlated with an individual's degree of allozyme heterozygosity. A total of 222 individuals were scored for their genotypes at seven allozyme loci, two nonspecific protein loci of unknown function and eight nuclear RFLPs detected by anonymous cDNA probes. In contrast to the enzyme loci, no correlation was observed between growth rate and the degree of heterozygosity at the DNA markers. Furthermore, there was no relationship between the magnitude of heterozygote deficiency at a locus and its effect on the correlation. The differences observed between the effects of allozyme and RFLP heterozygosity on growth rate provide evidence against the associative overdominance hypothesis, but a strong case against this explanation must await corroboration from similar studies in different species.

Animals↗

PubMed2002

Genetic and phenotypic correlations between antibody responses to Escherichia coli, infectious bursa disease virus (IBDV), and Newcastle disease virus (NDV), in broiler lines selected on antibody response to Escherichia coli.

The genetic control of antibody (Ab) response to Escherichia coli (EC), infectious bursa disease virus, and Newcastle disease virus and the genetic and phenotypic correlation between these Ab responses, were evaluated under farm conditions in which chicks were simultaneously exposed to these antigens. The experimental population comprised five groups: two lines divergently selected for high (HH) or low (LL) Ab response to EC vaccination; a commercial broiler dam-line (CC), from which HH and LL had been derived; and the HH x CC and LL x CC hybrid groups (HC and LC, respectively). Lines LL and HH expressed similar symmetric divergence to all three antigens. The ranking of the LL, LC, CC, HC, and HH genetic groups according to their mean Ab responses and their very high linear correlation with the LL vs. HH genomic scale clearly indicate the additive nature of the genetic divergence between these lines. Several estimates of correlation were calculated between Ab responses of each pair of antigens and between BW and Ab to each antigen. The high correlation between group means, the near-zero within-group correlation, and the low phenotypic correlation indicate the strongly positive genetic correlation between Ab responses and no correlation with BW. The results of this study suggest that overall immunocompetence of commercial broilers can be improved by selection for high Ab response of young chicks to controlled immunization with a single antigen, without counteracting further selection for high BW.

Animals↗

PubMed2001

Variation in mortality rates in Australia: correlation with Indigenous status, remoteness and socio-economic deprivation.

BACKGROUND: The aim of this study was to study ecological correlations between age-adjusted all-cause mortality rates in Australian statistical divisions and (1) the proportion of residents that self-identify as Indigenous, (2) remoteness, and (3) socio-economic deprivation. METHODS: All-cause mortality rates for 57 statistical divisions were calculated and directly standardized to the 1997 Australian population in 5-year age groups using Australian Bureau of Statistics (ABS) data. The proportion of residents who self-identified as Indigenous was obtained from the 1996 Census. Remoteness was measured using ARIA (Accessibility and Remoteness Index for Australia) values. Socioeconomic deprivation was measured using SEIFA (Socio-Economic Index for Australia) values from the ABS. RESULTS: Age-standardized all-cause mortality varies two-fold from 5.7 to 11.3 per 1,000 across Australian statistical divisions. Strongest correlation was between Indigenous status and mortality (r = 0.69, p < 0.001). Correlation between remoteness and mortality was modest (r = 0.39, p = 0.002) as was correlation between socio-economic deprivation and mortality (r = -0.42, p = 0.001). Excluding the three divisions with the highest mortality, a multiple regression model using the logarithm of the adjusted mortality rate as the dependent variable showed that the partial correlation (and hence proportion of the variance explained) for Indigenous status was 0.03 (9 per cent; p = 0.03), for SEIFA score was -0.17 (3 per cent; p = 0.22); and for remoteness was -0.22 (5 per cent; p = 0.13). Collectively, the three variables studied explain 13 per cent of the variability in mortality. CONCLUSIONS: Ecological correlation exists between all-cause mortality, Indigenous status, remoteness and disadvantage across Australia. The strongest correlation is with Indigenous status, and correlation with all three characteristics is weak when the three statistical divisions with the highest mortality rates are excluded. Intervention targeted at these three statistical divisions could reduce much of the variability in mortality in Australia.

Australia↗

PubMed2004

Contrast-enhanced dynamic and static MRI correlates with quantitative 99Tcm-labelled nanocolloid scintigraphy. Study of early rheumatoid arthritis patients.

OBJECTIVE: The aim of this study was to evaluate the roles of contrast-enhanced dynamic and static magnetic resonance imaging (MRI) and quantitative 99Tcm-labelled nanocolloid (NC) scintigraphy in detecting wrist joint inflammation in early rheumatoid arthritis (RA) patients. METHODS: Twenty-eight early RA patients (median symptom duration 5 months, range 1-12 months) underwent MRI, NC scintigraphy, laboratory and clinical examinations. Static wrist MRI scans were retrospectively scored for synovitis, bone oedema and erosions by two independent readers using the recently published rheumatoid arthritis MRI scoring system (RAMRIS). Twenty NC scans were analysed quantitatively by measuring maximum 99Tcm-NC uptake in three small areas of each wrist. From the same locations on the wrists, dynamic MRI gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) enhancement rates (E-rate) were measured. The average 99Tcm-NC uptake of the whole wrist region was also measured and average E-rates were calculated. Correlations between MRI and NC scintigraphy measurements were calculated. Correlations between imaging methods of the wrist and the global measures of inflammation (laboratory and clinical examinations) were also assessed. RESULTS: Strong correlations emerged between maximal 99Tcm-NC uptake and MRI E-rates, reflecting similar performance of the methods in detecting local synovial inflammation. 99Tcm-NC uptake and MRI E-rate correlated with semiquantitative scoring of synovitis and bone oedema from static MRI scans. The erythrocyte sedimentation rate (ESR) correlated with MRI scores, E-rate and 99Tcm-NC uptake. No correlation between the clinical parameters and the imaging methods was detected. Inter-observer reliability for scoring synovial hypertrophy, bone oedema and bone erosions from static MR images were high (single-measure fixed-effects intra-class correlations 0.87, 0.93 and 0.91 respectively). Intra-observer reliability for E-rate and 99Tcm-NC measurements of 10 randomly picked scans was found to be high, with an intra-class correlation of 0.92; 95% confidence interval (CI) 0.84-0.96 and 0.99; 95% CI 0.98-1.00, respectively. CONCLUSIONS: Objective information about wrist joint inflammation can be obtained with contrast-enhanced dynamic MRI and quantitative 99Tcm-labelled NC scintigraphy. MRI also allows visualization and semiquantitative scoring of bone oedema and erosions of the wrist. Dynamic MRI and NC scintigraphy are safe and easy to perform, and they can be used in a long-term follow-up of rheumatoid patients.

Adult↗

PubMed1990

Correlations between cardiorespiratory measures in normal infants and victims of sudden infant death syndrome.

Coordination between physiological measures (i.e., the tendency for measures to co-vary with each other) develops with maturation in the infant. We hypothesized that correlations between cardiorespiratory measures would increase with maturation in normal infants and that infants destined to die of sudden infant death syndrome (SIDS) would show lower correlations than those of age-matched controls. Twenty-two recordings of electrocardiogram and respiratory movements were obtained from infants who subsequently succumbed to SIDS and compared with 66 recordings from control infants. Each 1-min epoch of data was sleep-state classified. Median heart and respiratory rate, respiratory variability, and median extent of three types of heart rate variation were determined for each epoch, and the minute-by-minute correlations between seven pairs of parameters were determined for quiet sleep, rapid eye movement sleep, and waking in each recording. Most cardiorespiratory measures showed correlations that increased with age; the correlation coefficients for these measures tended to be lower in SIDS victims than in controls prior to 2 weeks of age. The correlations between heart rate and heart rate variability became lower with maturation; correlations between these measures tended to be higher in the SIDS victims. In all analyses showing significant maturational trends, the SIDS victims showed "less mature" correlations than those of the controls.

Arrhythmias, Cardiac↗

PubMed1993

Immunohistochemical and biochemical measurement of estrogen and progesterone receptors in primary breast cancer. Correlation of histopathology and prognostic factors.

OBJECTIVE: The authors investigated correlations of estrogen-receptor and progesterone-receptor with conventional risk factors as well as histopathology in patients with primary breast cancer. SUMMARY BACKGROUND DATA: Immunohistochemically determined hormone receptors have gained importance as prognosticators in primary breast cancer, but their definitive role has not yet been evaluated. METHODS: Tumor samples from 299 patients were examined for estrogen and progesterone receptors by biochemical and immunohistochemical assay. Correlations with established risk factors (tumor size, lymph node status, menopausal status, grading including subfactors) and histopathology were analyzed. RESULTS: The estrogen receptor, determined by immunohistochemical method revealed positivity in 80.6% of patients; biochemical measurement yielded 76.2% positive results. The progesterone receptor measured by immunohistochemistry yielded 61.3% positivity versus 55.8% detected by biochemical analysis. Invasive lobular, tubular, and ductal invasive carcinoma with prominent stroma content ("scirrhous carcinoma") rather than ductal invasive carcinoma was more frequently estrogen-receptor positive with immunohistochemistry than with biochemical assay. For progesterone receptor, the same pattern of positivity was seen with immunohistochemical assay. With progesterone receptor determined biochemically, "scirrhous" and lobular carcinoma showed positive results in a lower proportion than invasive ductal and tubular carcinoma. Significant correlations were observed between the estrogen-receptor status, the histologic grade of malignancy, nuclear polymorphism, and the rate of mitosis with both methods (p < 0.001 respectively). Different correlations were found between tumor size, menopausal status and estrogen receptor status with both assays respectively. For the progesterone receptor status, immunohistochemistry yielded significant correlations with the histologic grade of malignancy, nuclear polymorphism, rate of mitosis (p < 0.001 respectively) as well as growth pattern (p < 0.01), while biochemical analysis revealed a correlation with nuclear polymorphism (p < 0.05). The correlation analysis of both components of the immunoreactive score revealed a more significant impact of percentage of positive cells than of staining intensity. CONCLUSIONS: Immunohistochemistry detected a closer correlation between prognostic factors and receptor data than biochemical analysis.

Adult↗

PubMed2000

'Modeling' relationships among HIV-1 replication, immune activation and CD4+ T-cell losses using adjusted correlative analyses.

OBJECTIVE: To model the relationships among HIV-1 replication, immune activation and CD4+ T-cell losses in HIV-1 infection. METHODS: Cross-sectional analysis of baseline data from the Viral Activation by Transfusion Study. Comparisons of unadjusted and adjusted correlative analyses to establish models for mechanisms of cell loss in AIDS. RESULTS: Using these analyses, significant correlations were found among plasma levels of tumor necrosis factor alpha (TNFalpha) and its type two receptor (TNFrII), interleukin-6 (IL-6), beta2-microglobulin, expression of CD38 and HLA-DR on CD8+ T lymphocytes and plasma levels of HIV-1 RNA. When correlations among these indices were adjusted for possible intermediary correlations, the relationship between HIV-1 RNA levels and all plasma markers of immune activation could be accounted for by the correlation between plasma HIV-1 RNA and plasma TNFrII levels. In addition, the negative correlations that both HIV-1 RNA levels and TNFrII levels had with CD4+ T-cell counts were partially accounted for by the correlations of HIV-1 RNA and TNFrII with CD38 expression on CD8+ T cells. In persons with advanced disease (CD4+ T cells < 50 x 10(6)/l) IL-6 levels were inversely correlated with CD4+ T-cell counts. CONCLUSIONS: This analysis is consistent with a model wherein HIV-1 replication induces TNFalpha expression that induces multiple other indices of immune activation. In this model, HIV-1 replication and TNFalpha expression induce CD4+ T-cell losses at least in part through mechanisms reflected in heightened CD38 expression.

ADP-ribosyl Cyclase↗

PubMed1994

Multimodality correlative study of canine brain tumors. Proton magnetic resonance spectroscopy, positron emission tomography, and histology.

RATIONALE AND OBJECTIVES: Structural/functional relationships in an induced canine brain tumor were studied using proton-magnetic resonance spectroscopy (1H-MRS), positron emission tomography (PET), and histology. METHODS: Proton-MRS and PET data of implanted canine brain tumors were correlated with quantitative analysis of the tissue composition within the MRS and PET regions of interest (ROIs). Linear regression analysis was employed to correlate the 1H-MRS and PET data with the percent tumor and the percent total lesion (comprising tumor plus associated pathology ie, edema, cysts, hemorrhage, inflammation) within the ROI. RESULTS: Using 1H-MRS, N-acetyl aspartate concentrations were indirectly correlated with the amount of tumor (P = .058), as well as the amount of tumor plus associated pathology (P = .032) within the ROI. Total creatine concentrations were indirectly correlated with the amount of tumor and the amount of tumor plus associated pathology within the ROI (P < .05). Lactate concentrations were directly correlated with the amount of tumor (P = .053) and the amount of tumor plus associated pathology (P = .058) within the ROI. Using PET, Oxygen metabolic rates were indirectly correlated with the amount of tumor and with the amount of tumor plus associated pathology within the ROI (P < .05). Glucose metabolic rates were directly correlated with both the amount of tumor and with the amount of tumor plus associated pathology at P < .05. Proton-MRS measured concentrations of choline and PET measured values for blood flow, and oxygen extraction showed correlations with the amount of tumor and with the amount of tumor plus associated pathology at P > or = .08. CONCLUSIONS: The PET and MRS data were complementary with respect to suggesting anaerobic glucose metabolism for the tumor. Unlike other tumors, no increase in choline was noted in the canine tumor.

Animals↗

PubMed1995

Correlation between mobility restrictions and radiologic changes in ankylosing spondylitis.

STUDY DESIGN: In 151 adult patients with ankylosing spondylitis who participated in an inpatient rehabilitation program of 3-4 weeks, 10 different range of motion (ROM) values were measured, and their lumbar spine and sacroiliac joints were radiographed. OBJECTIVES: To determine whether a correlation obtained between restriction of ROM and progression of radiologic findings in ankylosing spondylitis, together with a high enough reliability level in measurements. SUMMARY OF BACKGROUND DATA: A significant correlation was observed between the restriction of eight ROMs: the Schober test, thoracolumbar rotation, thoracolumbar flexion, cervical rotation, occiput-wall distance, chin-chest distance, chest expansion, finger-floor distance, and overall radiologic changes in both lumbar spine and sacroiliac joints; straight leg raise did not correlate, and vital capacity only with sacroiliac joint changes. Spearman's correlation coefficients for ROMs were slightly higher to lumbar spine changes than to sacroiliac joint changes. A corresponding correlation was also observed between spinal mobility restrictions and six detailed changes in lumbar roentgenogram: syndesmophytes, apophyseal arthritis, sclerotic anterior borders of vertebrae, straightened anterior surface of vertebrae, and ossification of interspinous and anterior longitudinal ligaments. Other detailed lumbar spine findings did not correlate. As assessed by erythrocyte sedimentation rate values the disease activity increased in the course of radiologic progression, decreasing again, however, to the end stage. METHODS: Conventional methods with a tape and (Myrin) inclinometer were used to measure thoracolumbar flexion, cervical rotation, occiput-wall distance, chin-chest distance, finger-floor distance, chest expansion, vital capacity, and straight leg raise. In addition, a new method of thoracolumbar rotation and a new modification of the Schober test were introduced. Thirty-nine patients were randomized for a reliability assessment using repeated measurements of ROMs. Radiologic changes were evaluated (in a masked fashion) using the method of Dale and Vinje. RESULTS: The reliability of all ROMs was good (except for interrater intraclass correlation coefficients of chest expansion: 0.53). CONCLUSIONS: The clear correlation between radiologic sacroiliac joint and lumbar spine progression and eight ROMs showed that these are useful noninvasive measurements of disease progression and severity in ankylosing spondylitis that can be used in daily practice.

Adult↗

PubMed1994

The application of different correlation coefficients to assess the reproducibility of a food frequency questionnaire.

We computed four different correlation coefficients to investigate the degree of reproducibility of the weekly consumption of 77 food items or groups of foods and of seven summary questions from a food frequency questionnaire developed in Italy for a case-control study on cancers of the breast and digestive tract. The questionnaire had been administered twice to 452 Italian men and women. These included Pearson correlation coefficients (a) using the weekly frequencies of consumption without any transformation (P1); (b) after applying the transformation log (x + 1) (P2); (c) after applying the transformation log (x + 0.01) (P3); and (d) the Spearman correlation coefficient (SP). The mean values were 0.55 for P1, 0.59 for P2, 0.56 for P3 and 0.59 for SP. All coefficients were positively correlated, although to variable extents: the Spearman correlation coefficient between P2 and SP was 0.92, and that between P1 and P3 was 0.53. Differences between the four coefficients were more marked for food items with a lower kappa statistic and lower intraclass correlation, ie for those items with more severe reproducibility problems. Thus, a single correlation coefficient may not be enough to detect zones of the distribution of a food item where misclassification problems are more severe. The correlation coefficients used to investigate reproducibility should therefore be chosen on the basis of subsequent data analyses.

Feeding Behavior↗

PubMed2003

Correlation of low back pain with functional status, general health perception, social participation, subjective happiness, and patient satisfaction.

STUDY DESIGN: A cross-sectional and epidemiologic study investigated low back pain. OBJECTIVE: To assess the correlation among outcome measures for low back pain, including sciatica, according to a proposed low back pain-related model. SUMMARY OF BACKGROUND DATA: Various outcome measures are used in low back pain research: pain, functional status, generic health status, and patient satisfaction. Correlation among these measures has been unclear. METHODS: For this study, 816 subjects (369 men and 447 women; average age, 62 years) who underwent an adult medical examination. The patients were interviewed concerning their personal background, severity of low back pain and sciatica, functional status, general health perception, social participation, subjective happiness, and patient satisfaction. The correlation among these measures was analyzed systematically using path analysis based on a low back pain-related model hypothesizing that low back pain and sciatica worsen functional status and general health perception and then affect social participation, subjective happiness, and patient satisfaction. RESULTS: Restriction of functional status was found to be the most closely correlated with severity of low back pain. A decrease in physical health was most closely correlated with restriction of function. Social participation, subjective happiness, and patient satisfaction were closely correlated with physical health status. There was a significant correlation among outcome measures concerning physical health, which was consistent with a low back pain-related model. CONCLUSIONS: The outcome measures concerning physical health in this study were found to be correlated significantly, consistent with the proposed low back pain-related model.

Adult↗