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Significant Linear Correlation (significant + linear_correlation)
Selected AbstractsImmediate drug release from solid oral dosage formsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2005Thomas Schreiner Abstract Fast drug release from solid dosage forms requires a very fast contact of the vast majority of the drug particles with the solvent; this, however, is particularly delayed in tablets and granulations. Starch and cellulose substances favor the matrix disintegration during the starting phase and the generation of the effective dissolution surface of the drug substance, thereby. To investigate the very complex interrelation between the functionality of commonly used excipients and the structural effects of the production processes, wettability, porosity, water uptake, and drug release rates of several ketoprofen-excipient preparations (powder blends, granulations, tablets) were measured. Significant linear correlation between these parameters, however, was not achieved; only qualitative tendencies of the effects could be detected. In consequence, a general mathematical model describing the mechanistic steps of drug dissolution from solid dosage forms in a fully correct way was not realized. However, the time-dependent change of the effective dissolution surface follows stochastic models: a new dissolution equation is based on the differential Noyes-Whitney equation combined with a distribution function, e.g. the lognormal distribution, and numerically solved with the software system EASY-FIT by fitting to the observations. This new model coincides with the data to a considerably higher degree of accuracy than the Weibull function alone, particularly during the starting, matrix disintegration, and end phases. In combination with a procedure continuously quantifying the dissolved drug, this mathematical model is suitable for the characterization and optimization of immediate drug release by the choice and modification of excipients and unit operations. The interdependence of some characteristic effects of excipients and production methods is discussed. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:120,133, 2005 [source] Instrumental and Expert Assessment of Mahon Cheese TextureJOURNAL OF FOOD SCIENCE, Issue 7 2000J. Benedito ABSTRACT: To improve Mahon cheese texture assessment, the relationship between instrumental and sensory measurements was sought. For that purpose 30 pieces of Mahon cheese from different batches and 2 different manufacturers were examined. Textural characteristics at different curing times were evaluated by uniaxial compression, puncture, and sensory analysis. Significant linear correlations were found between instrumental and sensory measurements. A logarithmic model (Weber-Fechner) fitted data better than a linear one. Only 1 factor was extracted when considering all the instrumental and sensory variables, thus indicating that both sets of measurements are related to the same phenomenon. The best predictors for Mahon cheese sensory attributes were found to be cheese moisture, deformability modulus, and slope in puncture. [source] Baseline Echocardiographic Predictors of Dynamic Intraventricular Obstruction of the Left Ventricle during Dobutamine Stress EchocardiogramECHOCARDIOGRAPHY, Issue 10 2009Edmundo Jose Nassri Cāmara M.D., Ph.D. Background: Intraventricular obstruction (IVO) during dobutamine stress echocardiogram (DSE) may be associated with or reproduce symptoms. Predictors of IVO are not well established. Methods: 149 patients were studied at rest and during DSE. The normal range of the left ventricular outflow tract (LVOT) velocities was investigated in 68 healthy patients. Results: 19 patients (13%) developed IVO (peak LVOT velocity > 271 cm/sec). A significant linear correlation was observed between peak LVOT velocity during DSE and the following rest parameters: LV end-diastolic dimension (r =,0.20, P = 0.018), LV end-systolic dimension (r =, 0.27, P = 0.001), relative wall thickness (r = 0.23, P = 0.006), shortening fraction (r = 0.24, P = 0.004), LVOT diameter (r =, 0.20, P = 0.023) and LVOT velocity (r = 0.29, P < 0.0001). Only relative wall thickness (P = 0.012) and LVOT diameter (P = 0.027) were independent predictors of IVO. As a dichotomous variable, a relative wall thickness ,0.44 was the only independent predictor of IVO (OR 5.7, 95% CI 1.6,20, P = 0.006), with sensitivity, specificity, negative predictive value, and positive predictive value of 77%, 62%, 95%, and 21%, respectively, and global accuracy of 63% (area under the ROC curve = 0.7). IVO was significantly associated with general cardiovascular symptoms (P = 0.0006) and with chest pain (P = 0.008). Conclusions: Relative wall thickness and LVOT diameter were independent predictors of obstruction. As a dichotomous variable, a relative wall thickness , 0.44 was the only independent predictor of dynamic IVO. [source] Helicobacter pylori and Hepatitis a Virus Infection in School-Aged Children on Two Isolated Neighborhood Islands in TaiwanHELICOBACTER, Issue 3 2003Liang-Kung Chen ABSTRACT Background. The transmission routes of Helicobacter pylori and hepatitis A virus (HAV) infections have been extensively discussed in previous literature. However, whether H. pylori and HAV shared the same transmission pattern or not remains unclear. Lower socioeconomic status was recognized as a consistent risk factor to both infections. However, whether fecal-oral transmission was a risk factor to both infections is still under debate. Materials and Methods. In 1996, we conducted a cross-sectional study to evaluate the seroprevalence of antibody to H. pylori and HAV among the randomly selected school-aged children (age between 13 and 15) on Green Island (n = 91) and Lanyu Island (n = 138) (two isolated neighborhood islands near Taiwan Main Island). Results. The seroprevalence of H. pylori and HAV on the Green Island were 82.4% and 5.5%, respectively. The seroprevalence of H. pylori and HAV on Lanyu Island were 71.0% and 90.6%, respectively. H. pylori seroprevalence of all children and the subgroup of 13-year-olds was significantly lower on Lanyu Island than Green Island. However, it was not significantly different in subgroups of 14- and 15-year-olds. HAV seroprevalence was significantly higher on Lanyu Island than Green Island among all children and in each age subgroup. The correlation of H. pylori infection and HAV infection did not demonstrate significant linear correlation on both islands. Conclusions. In conclusion, H. pylori and HAV infections in school-aged children of 13,15 years of age on Green Island and Lanyu Island did not demonstrate significant correlation. The results of this study imply that H. pylori and HAV may share different transmission routes of infection. [source] Correlation between Moisture and Water Activity of Honeys Harvested in Different YearsJOURNAL OF FOOD SCIENCE, Issue 5 2004M.M. Cavia ABSTRACT: For the 1st time, a relationship has been investigated between moisture percentage (M) and water activity (aW) in honeys from 2 different harvesting years and 2 different climatic areas. Moisture was determined by measuring refractive index at 20°C, according to official methods. At the same time, aW of the same samples was assessed at exactly 20°C. Influence on the relationship of the crop's year, aging, and induced fine granulation was evaluated. The results show that, independent of all factors studied, an excellent and statistically significant linear correlation between both parameters [aW = 0.3114 + (0.0170 × M)] was found in all samples with a regression coefficient of 0.8809. The measurement of aW of honey is interesting but time-consuming. This study concludes that this parameter can be easily calculated from the moisture percentage, thus avoiding the use of expensive and slow equipment for aW measurement. [source] Systolic 3D first-pass myocardial perfusion MRI: Comparison with diastolic imaging in healthy subjectsMAGNETIC RESONANCE IN MEDICINE, Issue 4 2010Taehoon Shin Abstract Three-dimensional (3D) first-pass myocardial perfusion imaging (MPI) is a promising alternative to conventional two-dimensional multislice MPI due to its contiguous spatial coverage that is beneficial for estimating the size of perfusion defects. Data acquisition at mid-diastole is a typical choice for 3D MPI yet is sensitive to arrhythmia and variations in R-R interval that are common in cardiac patients. End systole is the second longest quiescent cardiac phase and is known to be less sensitive to the R-R variability. Therefore, 3D MPI with systolic acquisition may be advantageous in patients with severe arrhythmia once it is proven to be comparable to diastolic MPI in subjects with negligible R-R variation. In this work, we demonstrate the feasibility of 3D MPI with systolic data acquisition in five healthy subjects. We performed 3D MPI experiments in which 3D perfusion data were acquired at both end-systole and mid-diastole of every R-R interval and analyzed the similarity between resulting time intensity curves (TIC) from the two data sets. The correlation between systolic and diastolic TICs was extremely high (mean = 0.9841; standard deviation = 0.0166), and there was a significant linear correlation between the two time intensity curve upslopes and peak enhancements (P < 0.001). Magn Reson Med 63:858,864, 2010. © 2010 Wiley-Liss, Inc. [source] Effect of Maternal Protein Restriction During Pregnancy and Lactation on the Number of Cardiomyocytes in the Postproliferative Weanling Rat HeartTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 3 2010Kyungjoon Lim Abstract Maternal protein restriction leads to a reduction in the number of cardiomyocytes in the rat heart at birth. However, in rats, cardiomyocytes continue to proliferate until about 2 weeks after birth. Hence, this study aimed to examine the effect of maternal protein restriction, on the number of cardiomyocytes in the young rat heart at a time point when the cardiomyocytes have ceased proliferating and are terminally differentiated. Female Wistar Kyoto rats were fed either a normal protein diet (NPD; 20% casein) or a low protein diet (LPD; 8.7% casein) during pregnancy and lactation. Offspring (seven males and seven females per group) were perfusion fixed at 4 weeks of age. Heart volume and total cardiomyocyte number were determined using stereological techniques. At 4 weeks of age, body weights in both male and female LPD offspring were significantly reduced compared with NPD controls whereas relative heart volumes were significantly increased in LPD offspring. Total number of cardiomyocytes was not significantly different between groups. In both groups, there was a significant linear correlation between cardiomyocyte number and heart volume. In conclusion, total cardiomyocyte number in the postproliferative rat heart does not appear to be affected by maternal protein restriction per se but is directly related to heart size. Anat Rec, 2010. © 2010 Wiley-Liss, Inc. [source] Anatomy and ultrasonography of the normal kidney in brown lemurs: Eulemur fulvusAMERICAN JOURNAL OF PRIMATOLOGY, Issue 8 2009Fidiniaina Raharison Abstract The purpose of this study is to describe the anatomy and obtain echographic measurements of normal kidneys in brown lemurs (Eulemur fulvus). The anatomical findings show that brown lemur kidneys are comparable to those of rats except for an elongated papilla. The kidneys of 16 (7 females and 9 males) lemurs were examined with two-dimensional and power Doppler ultrasonography under general anesthesia. Morphometrically, the left and right kidney surface areas are comparable (3.29 and 3.51,cm2). Kidney area has a significant linear correlation with body weight. Echo-Doppler findings show that the mean renal arterial blood flow speeds for the left and right kidneys are comparable (0.70 and 0.73,m/s). However, flow speed is higher in the male (0.79,m/s) than in the female (0.60,m/s). The renal arterial diameters are between 1.0 and 1.8,mm. The fact that anesthesia can have hemodynamic effects on renal vasculature should be taken into consideration when assessing these echographic results. Am. J. Primatol. 71:647,653, 2009. © 2009 Wiley-Liss, Inc. [source] Cesarean Section Rates and Maternal and Neonatal Mortality in Low-, Medium-, and High-Income Countries: An Ecological StudyBIRTH, Issue 4 2006Fernando Althabe MD ABSTRACT: Background: Cesarean section rates show a wide variation among countries in the world, ranging from 0.4 to 40 percent, and a continuous rise in the trend has been observed in the past 30 years. Our aim was to explore the association of cesarean section rates of different countries with their maternal and neonatal mortality and to test the hypothesis that in low-income countries, increasing cesarean section rates were associated with reductions in both outcomes, whereas in high-income countries, such association did not exist. Methods: We performed a cross-sectional multigroup ecological study using data from 119 countries from 1991 to 2003. These countries were classified into 3 categories: low-income (59 countries), medium-income (31 countries), and high-income (29 countries) countries according to an international classification. We assessed the ecological association between national cesarean section rates and maternal and neonatal mortality by fitting multiple linear regression models. Results: Median cesarean section rates were lower in low-income than in medium- and high-income countries. Seventy-six percent of the low-income countries, 16 percent of the medium-income countries, and 3 percent of high-income countries showed cesarean section rates between 0 and 10 percent. Three percent of low-income countries, 36 percent of medium-income countries, and 31 percent of high-income countries showed cesarean section rates above 20 percent. In low-income countries, a negative and statistically significant linear correlation was observed between cesarean section rates and neonatal mortality and between cesarean section rates and maternal mortality. No association was observed in medium- and high-income countries for either neonatal mortality or maternal mortality. Conclusions: No association between cesarean section rates and maternal or neonatal mortality was shown in medium- and high-income countries. Thus, it becomes relevant for future good-quality research to assess the effect of the high figures of cesarean section rates on maternal and neonatal morbidity. For low-income countries, and on confirmation by further research, making cesarean section available for high-risk pregnancies could contribute to improve maternal and neonatal outcomes, whereas a system of care with cesarean section rates below 10 percent would be unlikely to cover their needs. (BIRTH 33:4 December 2006) [source] Pharmacokinetics of intravenous and oral midazolam in plasma and saliva in humans: usefulness of saliva as matrix for CYP3A phenotypingBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 4 2008Bettina Link WHAT IS ALREADY KNOWN ABOUT THE SUBJECT , Midazolam is a frequently used probe drug for CYP3A phenotyping in plasma. Midazolam and its hydroxy-metabolites can be detected in saliva. WHAT THIS STUDY ADDS , The concentrations of midazolam and its hydroxy-metabolites are much lower in saliva than in plasma, but the midazolam concentrations in both matrices show a significant linear correlation. , Saliva appears to be a suitable matrix for CYP3A phenotyping with midazolam, but very sensitive methods are required due to the low concentrations of midazolam and its hydroxy-metabolites. AIMS To compare midazolam kinetics between plasma and saliva and to find out whether saliva is suitable for CYP3A phenotyping. METHODS This was a two way cross-over study in eight subjects treated with 2 mg midazolam IV or 7.5 mg orally under basal conditions and after CYP3A induction with rifampicin. RESULTS Under basal conditions and IV administration, midazolam and 1,-hydroxymidazolam (plasma, saliva), 4-hydroxymidazolam and 1,-hydroxymidazolam-glucuronide (plasma) were detectable. After rifampicin, the AUC of midazolam [mean differences plasma 53.7 (95% CI 4.6, 102.9) and saliva 0.83 (95% CI 0.52, 1.14) ng ml,1 h] and 1,-hydroxymidazolam [mean difference plasma 11.8 (95% CI 7.9 , 15.7) ng ml,1 h] had decreased significantly. There was a significant correlation between the midazolam concentrations in plasma and saliva (basal conditions: r = 0.864, P < 0.0001; after rifampicin: r = 0.842, P < 0.0001). After oral administration and basal conditions, midazolam, 1,-hydroxymidazolam and 4-hydroxymidazolam were detectable in plasma and saliva. After treatment with rifampicin, the AUC of midazolam [mean difference plasma 104.5 (95% CI 74.1, 134.9) ng ml,1 h] and 1,-hydroxymidazolam [mean differences plasma 51.9 (95% CI 34.8, 69.1) and saliva 2.3 (95% CI 1.9, 2.7) ng ml,1 h] had decreased significantly. The parameters separating best between basal conditions and post-rifampicin were: (1,-hydroxymidazolam + 1,-hydroxymidazolam-glucuronide)/midazolam at 20,30 min (plasma) and the AUC of midazolam (saliva) after IV, and the AUC of midazolam (plasma) and of 1,-hydroxymidazolam (plasma and saliva) after oral administration. CONCLUSIONS Saliva appears to be a suitable matrix for non-invasive CYP3A phenotyping using midazolam as a probe drug, but sensitive analytical methods are required. [source] Investigation of the molecular surface area and volume: Defined and calculated by the molecular face theoryJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 11 2010Li-Dong Gong Abstract Based on the molecular face (MF) theory, the molecular face surface area (MFSA) and molecular face volume (MFV) are defined. For a variety of organic molecules and several inorganic molecules, the MFSA and MFV have been studied and calculated in terms of an algorithm of our own via the Matlab package. The MFV shows a very good linear relationship with the experimentally measured critical molar volume. It is also found that the MFSA and MFV have significant linear correlations with those of the commonly used hard-sphere model and the electron density isosurface. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010 [source] | ||||||||||||||||