Home About us Contact
|
Home About us Contact | ||
|
|
||
Correlation R (correlation + r)
Selected AbstractsSwitching from HPLC/UV to MEIA for whole blood sirolimus quantitation: comparison of methodsJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 6 2006Luigi Alberto Pini Abstract Sirolimus is a immunosuppressive agent for renal transplant recipients. Monitoring of whole blood sirolimus concentration is necessary in order to improve clinical outcomes. An increasing number of clinical laboratories (4,14% during 2005) are using microparticle enzyme immunoassay (MEIA) for sirolimus quantitation but previous reports indicated a high variability, with a mean difference of 17% for MEIA method vs. high-performance liquid chromatography/ultraviolet (HPLC/UV). This study was aimed at comparing the reliability of MEIA with the HPLC/UV method. Blood samples from transplant patients were processed using both HPLC/UV and MEIA assays. Comparison and Bland-Altman plots, as well as regression analysis and paired t -test were used to compare results of the assays. Concentrations were stratified into three groups and used to investigate whether any observed difference between methods could be influenced by sirolimus concentration. Regression analysis yielded a coefficient of correlation R of 0.9756, the line of best fit being y=0.9832x+0.1976. The statistical analysis showed no difference between the two sets of experimental data. The average percentage difference between the two methods was found to be ,0.2±19.2%. On the basis of our present results, the tested MEIA assay is able to quantify sirolimus concentration with a clinically acceptable imprecision, similar to that of HPLC/UV method. J. Clin. Lab. Anal. 20:239,244, 2006. © 2006 Wiley-Liss, Inc. [source] Bone material quality in transiliac bone biopsies of postmenopausal osteoporotic women after 3 years of strontium ranelate treatmentJOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2010Paul Roschger Abstract Strontium ranelate (SrR) is a relatively new treatment for osteoporosis. In this study we investigated its potential impact on human bone material quality in transiliac bone biopsies from postmenopausal osteoporotic women treated 3 years with calcium and vitamin D plus either 2,g SrR per day or placebo. Bone mineralization density distribution (BMDD), strontium (Sr) concentration, collagen cross-link ratio, and indentation modulus were analyzed by quantitative backscattered electron imaging, electron-induced X-ray fluorescence analysis, synchrotron radiation induced micro X-ray fluorescence elemental mapping, Fourier transform infrared imaging, and nanoindentation, respectively. The BMDD of SrR-treated patients was shifted to higher atomic numbers (Zmean +1.5%, p,<,.05 versus placebo). We observed Sr being preferentially incorporated in bone packets formed during SrR treatment up to 6% atom fraction [Sr/(Sr,+,Ca)] depending on the SrR serum levels of the individuals (correlation r,=,0.84, p,=,.018). Collagen cross-link ratio was preserved in SR-treated bone. The indentation modulus was significantly decreased in younger versus older bone packets for both placebo- (,20.5%, p,<,.0001) and SrR-treated individuals (,24.3%, p,<,.001), whereas no differences were found between the treatment groups. In conclusion, our findings indicate that after SrR treatment, Sr is heterogeneously distributed in bone and preferentially present in bone packets formed during treatment. The effect of SrR on BMDD seems to be due mainly to the uptake of Sr and not to changes in bone calcium content. Taken together, these data provide evidence that the investigated bone quality determinants at tissue level were preserved in postmenopausal osteoporotic women after 3-year treatment with 2,g SrR per day plus calcium and vitamin D. © 2010 American Society for Bone and Mineral Research [source] Analysis of the Defibrillation Efficacy for 5-ms WaveformsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2004DONGXU GUAN Ph.D. Introduction: Empirical studies have shown that biphasic defibrillation waveforms are more efficacious than monophasic waveforms. However, a more systematic approach to waveform development might be more productive. This study tested 147 multiphasic waveforms uniformly sampled from all possible 5-ms waveforms. Methods and Results: One hundred ninety-eight guinea pigs (850,1,050 g) received 30 episodes of ventricular fibrillation followed by transthoracic defibrillation. The first 10 shocks were used to determine the ED50 for a biphasic control. Then, 20 waveforms including 2 controls were tested once at the ED50. Of the 147 waveforms tested here, 21 waveforms showed equivalent or greater efficacies than the biphasic control, with one being statistically more efficacious (P < 0.05). Two fundamental assumptions were addressed: (1) similarly efficacious waveforms are analytically similar, and (2) a single optimal waveform can be described. The mean percentage of similarly efficacious waveforms with similar shapes was greater than zero in the most efficacious 21 waveforms (P = 0.023), but less efficacious waveforms showed randomly distributed shapes. Cluster analysis revealed that the best waveforms share a major phase containing most of the defibrillation energy. The optimal waveform shape extrapolated from the sample waveforms was a 2.5/1-ms biphasic-type waveform (highest correlation r = 0.701, P < 0.001). Conclusion: This work supports the assumption that efficacious waveforms are similarly shaped and the notion that one single optimum exists. (J Cardiovasc Electrophysiol, Vol. 15, pp. 447-454, April 2004) [source] Search for occult secondary osteoporosis: impact of identified possible risk factors on bone mineral densityJOURNAL OF INTERNAL MEDICINE, Issue 5 2002H. A. Deutschmann Abstract. Deutschmann HA, Weger M, Weger W, Kotanko P, Deutschmann MJ, Skrabal F (Krankenhaus der Barmherzigen Brüder, Marschallgasse, Teaching Hospital of the Karl-Franzens University Graz, Austria). Search for occult secondary osteoporosis: impact of identified possible risk factors on bone mineral density. J Intern Med 2002; 252: 389,397. Objectives. To determine whether the use of more elaborate diagnostic tests can identify possible risk factors for secondary osteoporosis and to evaluate the impact of these possible risk factors on the severity of bone disease in the study population. Design. Cross-sectional study. Setting and participants. ,We have investigated 377 subjects (285 females, 92 males) with osteoporosis (T-score less than ,2.5 in dual energy X-ray absorption) or nontraumatic lumbar vertebral fractures; these patients were referred to our hospital, a secondary care centre, for evaluation and treatment of osteoporosis. Results. Osteoporosis without attributable risk factor was diagnosed in 106 women (37%) and 30 men (33%). In 241 patients (179 women, 62 men) one or more possible risk factors for osteoporosis (in this paper also called subclinical disease) were revealed. The most common were lactose malabsorption, disturbed exocrine pancreatic function and renal tubular disturbances, including renal hypercalciuria, incomplete renal tubular acidosis and mild phosphate diabetes. The number of possible risk factors in the individual patient was significantly related to the severity of osteoporosis as assessed by Z-scores (Spearman correlation r = ,0.43, P < 0.001, n = 172 for females; r = ,0.28, P < 0.05, n = 65 for males). Conclusions. All the identified subclinical diseases would have remained undetected if the currently accepted guidelines for the investigation of patients with osteoporosis were applied. The statistically significant correlation between the number of identified possible risk factors and the severity of bone disease in the individual patient strongly suggests the pathogenetic significance of the identified subclinical diseases. It is yet to be shown, whether specific treatment of these subclinical diseases yields additional improvement of bone mass as compared with standard treatment of osteoporosis. [source] Determination of the Minimal Erythema Dose and Colorimetric Measurements as Indicators of Skin Sensitivity to UV-B Radiation,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2004Sérgio Dornelles ABSTRACT There is a strong relation between chronic UV-B-induced sunburns and the development of skin cancer. Therefore, it is important to obtain a method that can be reproduced easily to detect individuals with similar skin color but different sensitiveness to sun exposure. The study evaluated 193 healthy volunteers (68% women; the average age was 38 years). They were divided into six groups of at least 30 subjects, according to skin type. The minimal erythema dose (MED) was assessed in two non-sun-exposed areas (thorax-infra-axillary area and on the buttocks), using a UV-B source (0.5 mW/cm2), with openings of 1 cm2, in increasing doses. The same areas were evaluated with a Minolta CR 300 Chromameter (L*a*b* system). The MED values ranged from 13 to 156 mJ/cm2; the coordinate L* (brightness) ranged from 75.96 to 30.15. The correlation between the MED and the brightness was negative in both areas (Pearson's correlation r =,0.91, P < 0.05). Color measurements, especially brightness, can be used to quickly assess skin sensibility. Considering the MED, there is a substantial overlapping of adjacent phototypes, but they could be separated into two groups: more sensitive individuals (Types I, II, III and IV) and less sensitive ones (Types V and VI). [source] Carbon and Oxygen Isotopic Composition of Surface-Sediment Carbonate in Bosten Lake (Xinjiang, China) and its Controlling FactorsACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2009Chengjun ZHANG Abstract: Bosten Lake is a mid-latitude lake with water mainly supplied by melting ice and snow in the Tianshan Mountains. The depositional environment of the lake is spatially not uniform due to the proximity of the major inlet and the single outlet in the western part of the lake. The analytical results show that the carbon and oxygen isotopic composition of recent lake sediments is related to this specific lacustrine depositional environment and to the resulting carbonate mineralogy. In the southwestern lake region between the Kaidu River inlet and the Kongqi River outlet, carbon isotope composition (,13C) values of the carbonate sediment (,1, to ,2,) have no relation to the oxygen isotope composition of the carbonate (,18O) values (,7, to ,8,), with both isotopes showing a low variability. The carbonate content is low (<20%). Carbonate minerals analyzed by X-ray diffraction are mainly composed of calcite, while aragonite was not recorded. The salinity of the lake water is low in the estuary region as a result of the Kaidu River inflow. In comparison, the carbon and oxygen isotope values are higher in the middle and eastern parts of the lake, with ,13C values between approximately +0.5, and +3,, and ,18O values between ,1, and ,5,. There is a moderate correlation between the stable oxygen and carbon isotopes, with a coefficient of correlation r of approximately 0.63. This implies that the lake water has a relatively short residence time. Carbonate minerals constitute calcite and aragonite in the middle and eastern region of the lake. Aragonite and Mg,calcite are formed at higher lake water salinity and temperatures, and larger evaporation effects. More saline lake water in the middle and eastern region of the lake and the enhanced isotopic equilibrium between water and atmospheric CO2 cause the correlating carbon and oxygen isotope values determined for aragonite and Mg,calcite. Evaporation and biological processes are the main reasons for the salinity and carbonate mineralogy influence of the surface-sediment carbonate in Bosten Lake. The lake water residence time and the CO2 exchange between the atmosphere and the water body control the carbon and oxygen isotope composition of the carbonate sediment. In addition, organic matter pollution and decomposition result in the abnormally low carbon isotope values of the lake surface-sediment carbonate. [source] Relation of microvessel density with microvascular invasion, metastasis and prognosis in renal cell carcinomaBJU INTERNATIONAL, Issue 6 2008Esin Yildiz OBJECTIVE To clarify the significance of microvessel density (MVD) in a retrospective investigation the relationship between the pattern of MVD (reflecting angiogenesis), and tumour stage, grade, size, and occurrence of microvessel invasion (MVI), metastasis, and cancer-specific survival (CSS) in patients who had surgery for renal cell carcinoma (RCC). PATIENTS AND METHODS Vessels were labelled in sections of formalin-fixed, paraffin-embedded tissues from 54 RCCs by CD34 immunohistochemistry. The mean MVD, expressed as the number of vessels per 10 high-power fields (HPF, ×400) were measured for each case. In addition, all pathological slides were reviewed for the presence and absence of MVI. The prognostic value of MVD and MVI was then evaluated, and correlated with the usual prognostic variables, tumour metastasis and CSS. RESULTS In a univariate analysis of CSS, the MDV tended to be lower as stage increased from pT1 to pT3, and as grade increased from G1 to G4, although it was statistically significant only for stage (P < 0.001 and 0.050, respectively). The mean MVD was higher in 42 nonmetastatic than in 12 metastatic tumours, and in 33 tumours associated with MVI than in 21 with no MVI (P < 0.001). The mean MVD was also lower and significantly different for 28 large than 26 small tumours (P = 0.005). The survival rate of patients with tumours that were small, low-stage, of higher MVD, with no MVI and metastasis was significantly higher than that of patients with large, high-stage, low MVD, with MVI and metastatic tumours (all P < 0.001). MVI was significantly more common with a decreasing trend in MVD and the presence of metastasis (Spearman rank correlation rs = ,0.68, P = 0.01, and rs = 0.39, P = 0.01, respectively). Independent prognostic factors in a multivariate analysis were: in all patients with RCC, tumour stage (P = 0.013) and metastasis (P = 0.028); in those with low MVD, MVI (P = 0.004) and metastases (P = 0.016); in those with no MVI, stage (P = 0.020); in those with MVI, MVD (P = 0.001); in those with no metastases, stage (P = 0.045); and in those with metastases, MVD (P < 0.001). No independent predictor was identified in patients with high MVD. In patients with no metastases there was a significantly shorter median CSS time in RCCs with low MVD and with MVI (P = 0.004 for both). Similarly, patients who had grade 3,4 tumours, vs those with lower MVD and with MVI, had a significantly shorter median CSS (P = 0.020 for MVD, and 0.01 for MVI). CONCLUSIONS This study suggested that MVD in RCC was inversely associated with MVI, tumour metastasis, patient survival and tumour diameter and stage, from the usual prognostic variables, but MVD was not an independent prognostic factor in multivariate analysis for all patients with RCC. Low MVD and the presence of MVI appears to be a marker for identifying patients with an adverse prognosis. [source] | ||||||||||