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Potential Correlation (potential + correlation)
Selected AbstractsVariable-field relaxometry of iron-containing human tissues: a preliminary studyCONTRAST MEDIA & MOLECULAR IMAGING, Issue 4 2009Aline Hocq Abstract Excess iron is found in brain nuclei from neurodegenerative patients (with Parkinson's, Alzheimer's and Huntington's diseases) and also in the liver and spleen of cirrhosis, hemochromatosis and thalassaemia patients. Ferritin, the iron-storing protein of mammals, is known to darken T2 -weighted MR images. Understanding NMR tissue behavior may make it possible to detect those diseases, to follow their evolution and finally to establish a protocol for non-invasive measurement of an organ's iron content using MRI methods. In this preliminary work, the MR relaxation properties of embalmed iron-containing tissues were studied as well as their potential correlation with the iron content of these tissues. Relaxometric measurements (T1 and T2) of embalmed samples of brain nuclei (caudate nucleus, dentate nucleus, globus pallidus, putamen, red nucleus and substantia nigra), liver and spleen from six donors were made at different magnetic fields (0.00023,14 T). The influence of the inter-echo time on transverse relaxation was also studied. Moreover, iron content of tissues was determined by inductively coupled plasma atomic emission spectroscopy. In brain nuclei, 1/T2 increases quadratically with the field and depends on the inter-echo time in CPMG sequences at high fields, both features compatible with an outer sphere relaxation theory. In liver and spleen, 1/T2 increases linearly with the field and depends on the inter-echo time at all fields. In our study, a correlation between 1/T2 and iron concentration is observed. Explaining the relaxation mechanism for these tissues is likely to require a combination of several models. The value of 1/T2 at high field could be used to evaluate iron accumulation in vivo. In the future, confirmation of those features is expected to be achieved from measurements of fresh (not embalmed) human tissues. Copyright © 2009 John Wiley & Sons, Ltd. [source] Role of transcription factors Ad4bp/SF-1 and DAX-1 in steroidogenesis and spermatogenesis in human testicular development and idiopathic azoospermiaINTERNATIONAL JOURNAL OF UROLOGY, Issue 6 2006YOSHIYUKI KOJIMA Background:, Ad4bp/SF-1 and DAX-1 are orphan members of the nuclear hormone receptor superfamily of transcription factors. In order to obtain better understandings of human testicular steroidogenesis and spermatogenesis, we examined the expression levels of both factors in human normal and idiopathic azoospermic testes and investigated their physical meaning. Methods:, First, we examined the expression level of Ad4bp/SF-1 and DAX-1 by quantitative reverse transcription,polymerase chain reaction (RT,PCR), immunohistochemistry and western blotting analysis using eight normal human testicular tissues from infants to adults. Second, we performed quantitative RT,PCR using testicular biopsy samples obtained from 22 idiopathic azoospermic patients to examine the expression of Ad4bp/SF-1 and DAX-1, and analysed the correlation between the expression levels of both factors and the serum hormone levels or histological evaluation to study their potential correlation with steroidogenesis and spermatogenesis on idiopathic azoospermia. Results:, The expression levels of both factors in the normal testes increased with testicular development. Ad4bp/SF-1 was abundantly expressed in Leydig cell, whereas DAX-1 was expressed in Sertoli cells. The expression level of Ad4bp/SF-1 in idiopathic azoospermic patients testes positively correlated with serum testosterone (P < 0.05). The average expression levels of DAX-1 mRNA for patients with maturation arrest (0.39 ± 0.19) and Sertoli cell-only syndrome (0.13 ± 0.08) were lower than that with hypospermatogenesis (1.60 ± 1.32) and normal spermatogenesis (1.30 ± 1.41). Conclusion:, Ad4bp/SF-1 is important for the maintenance of steroidogenesis in the human testis. DAX-1 plays a critical role in spermatogenesis in the human testis, and Sertoli cell-only syndrome and maturation arrest may result from abnormal Sertoli cell function that disrupts the normal progression of spermatogenesis. [source] Obtaining a thorough sleep history and routinely screening for obstructive sleep apneaJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 4 2008FNP-BC, Jamie Lamm RN Abstract Purpose: To present a clinical case study of obstructive sleep apnea (OSA) and discuss a potential correlation between OSA, unexplained distal pain symptoms, and pyschoemotional concerns. Data sources: A review of the scientific literature was performed on OSA using the Cumulative Index of Nursing and Allied Health Literature and MEDLINE. Conclusions: OSA is potentially life threatening and can have serious consequences to a patient's health. Many of the obvious signs of OSA occur at night, and the symptoms of OSA may correspond to a variety of other diseases. Clinicians should recognize a possible correlation between OSA and unexplained distal pain symptoms as well as psychoemotional concerns. These clinically associated conditions may be less apparent but may dramatically affect quality of life. By improving recognition and treatment of OSA, morbidity and mortality can be reduced and quality of life can be improved for patients and their families. Implications for practice: It is imperative that clinicians are attentive and take detailed histories to recognize the clinical signs and symptoms of OSA, paying more attention to the less obvious symptomatology that may be significantly impacting quality of life. [source] Application of GIS for processing and establishing the correlation between weather radar reflectivity and precipitation dataMETEOROLOGICAL APPLICATIONS, Issue 1 2005Y. Gorokhovich Correlation between weather radar reflectivity and precipitation data collected by rain gauges allows empirical formulae to be obtained that can be used to create continuous rainfall surfaces from discrete data. Such surfaces are useful in distributed hydrologic modelling and early warning systems in flood management. Because of the spatial relationship between rain gauge locations and radar coverage area, GIS provides the basis for data analysis and manipulation. A database of 82 radar stations and more than 1500 rain gauges in continental USA was compiled and used for the continuous downloading of radar images and rain data. Image sequences corresponding to rain events were extracted for two randomly selected radar stations in South and North Carolina. Rainfall data from multiple gauges within the radar zone of 124 nautical miles (nm) (,230 km) were extracted and combined with corresponding reflectivity values for each time interval of the selected rain event. Data were normalised to one-hour intervals and then statistical analysis was applied to study the potential correlation. Results of regression analysis showed a significant correlation between rain gauge data and radar reflectivity values and allowed derivation of empirical formulae. Copyright © 2005 Royal Meteorological Society. [source] Proliferation and neurogenesis of neural stem cells enhanced by cerebral microvascular endothelial cellsMICROSURGERY, Issue 1 2008Ying Guo M.D. In adult mammalian brain, vascular cells reside throughout life, close to central nervous system germinal zones, and neural stem cells (NSCs) mainly localize in the dentate gyrus of the hippocampus, subventricular zone, and olfactory bulb. Microvessels appear to produce a special microenvironment that may influence the characteristics of NSCs. To explore this potential correlation, an in vitro model with cocultured cerebral microvascular endothelial cells (CMECs) and NSCs was established in our study by using a transwell coculture system. The expression of nestin and NF in the early stage of coculture, and NF in the late stage, was detected by immunostaining. The results demonstrated that CMECs can stimulate self-renewal of NSCs and inhibit their differentiation, implying the potential of CMECs in promoting the neural differentiation of NSCs. © 2007 Wiley-Liss, Inc. Microsurgery, 2008. [source] Bayesian Inference for Smoking Cessation with a Latent Cure StateBIOMETRICS, Issue 3 2009Sheng Luo Summary We present a Bayesian approach to modeling dynamic smoking addiction behavior processes when cure is not directly observed due to censoring. Subject-specific probabilities model the stochastic transitions among three behavioral states: smoking, transient quitting, and permanent quitting (absorbent state). A multivariate normal distribution for random effects is used to account for the potential correlation among the subject-specific transition probabilities. Inference is conducted using a Bayesian framework via Markov chain Monte Carlo simulation. This framework provides various measures of subject-specific predictions, which are useful for policy-making, intervention development, and evaluation. Simulations are used to validate our Bayesian methodology and assess its frequentist properties. Our methods are motivated by, and applied to, the Alpha-Tocopherol, Beta-Carotene Lung Cancer Prevention study, a large (29,133 individuals) longitudinal cohort study of smokers from Finland. [source] Analysis of the possibility of the relationship between various implant-related measures: an 18-month follow-up studyJOURNAL OF ORAL REHABILITATION, Issue 2 2008T. F. TÖZÜM Summary, Better clarification of the long-term relationship among the various implant-related measures could improve the evaluation process for dental implants. Thus, the aim of the present study was to determine the potential correlations among the volumetric features and nitric oxide content of peri-implant sulcus fluid (PISF) and measures of implant stability, and the marginal bone loss. Completely edentulous patients (n = 15) treated with dental implants and ball attachment mandibular over dentures were included. Resonance frequency analysis (RFA), marginal bone level measurements, PISF volume and spectrophotometrically determined nitrite levels were recorded for all dental implant sites. Measures for early (n = 16) and delayed (n = 14) loaded dental implants were comparatively analysed for a period of 18 months. Some random correlations between PISF volume and marginal bone level, PISF nitrite level and marginal bone level and PISF volume and PISF nitrite content, and RFA and PISF volume were observed. However, the only constant correlation was noticed between implant stability (RFA scores) and marginal bone level. This correlation was negative and significant for all dental implants and for delayed loaded implants (P < 0·05). The pattern of loading seemed to affect the extent, but not the pattern of this relationship. While some of the implant-related measures may be strongly associated (e.g. dental implant stability and marginal bone level), not all measures from a single implant site are likely to be related. Such associations may be under the influence of a variety of factors including the loading protocol of dental implants. [source] Effect of varying feedstock,pretreatment chemistry combinations on the formation and accumulation of potentially inhibitory degradation products in biomass hydrolysatesBIOTECHNOLOGY & BIOENGINEERING, Issue 3 2010Bowen Du Abstract A variety of potentially inhibitory degradation products are produced during pretreatment of lignocellulosic biomass. Qualitative and quantitative interrogation of pretreatment hydrolysates is paramount to identifying potential correlations between pretreatment chemistries and microbial inhibition in downstream bioconversion processes. In the present study, corn stover, poplar, and pine feedstocks were pretreated under eight different chemical conditions, which are representative of leading pretreatment processes. Pretreatment processes included: 0.7% H2SO4, 0.07% H2SO4, liquid hot water, neutral buffer solution, aqueous ammonia, lime, lime with oxygen pressurization, and wet oxidation. Forty lignocellulosic degradation products resulting from pretreatment were analyzed using high performance liquid chromatography in combination with UV spectroscopy or tandem mass spectrometry detection (HPLC-PDA-MS/MS) and ion chromatography (IC). Of these compounds, several have been reported to be inhibitory, including furfural, hydroxymethyl furfural, ferulic acid, 3,4-dihydroxybenzaldehyde, syringic acid among others. Formation and accumulation of monitored compounds in hydrolysates is demonstrated to be a function of both the feedstock and pretreatment conditions utilized. Biotechnol. Bioeng. 2010;107: 430,440. © 2010 Wiley Periodicals, Inc. [source] Association between serum levels of soluble tumor necrosis factor receptors/CA 125 and disease progression in patients with epithelial ovarian malignancy,,CANCER, Issue 1 2004A Gynecologic Oncology Group study Abstract BACKGROUND A prospective study was undertaken within the Gynecologic Oncology Group to determine whether serum levels of soluble tumor necrosis factor receptors I (sTNFR-I) and II (sTNFR-II), alone or in combination with CA 125, were associated with clinicopathologic characteristics or outcome in patients with epithelial ovarian malignancies. METHODS Quantitative immunoassays were performed on valid pretreatment serum specimens obtained from patients with epithelial ovarian malignancies to assess levels of sTNFR-I, sTNFR-II, and CA 125. The authors then analyzed the results of these immunoassays for potential correlations with clinicopathologic characteristics and outcome. RESULTS The median age of the 139 women evaluated was 59 years. Seventy-eight percent had Stage III or IV disease, and 58% had serous carcinomas. sTNFR-II was associated with age (P = 0.013), and CA 125 was associated with histologic subtype (P = 0.0009). In addition, sTNFR-I (P = 0.037) and CA 125 (P < 0.0001) were associated with extent of disease. After adjusting for patient age, histologic subtype, and extent of disease, all three biomarkers were predictive of progression-free survival, but not overall survival, when the combination was included in the model. The authors observed a 51% reduction (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.24,0.99), a 2.9-fold increase (HR, 2.87; 95% CI, 1.15,7.20), and a 22% increase (HR, 1.22; 95% CI, 0.99,1.51) in the risk of progression for each unit increase in the log-transformed levels of sTNFR-I, sTNFR-II, and CA 125, respectively. CONCLUSIONS The observations made in the current study,that among patients with low or high CA 125 levels, those with high sTNFR-I levels and low sTNFR-II levels had the lowest risk, that patients with low-low or high-high sTNFR-I and sTNFR-II levels, respectively, had an intermediate risk, and that patients with low sTNFR-I levels and high sTNFR-II levels had the highest risk of progression,suggested the potential value of simultaneous assessment of all three biomarkers in patients with epithelial ovarian malignancies. Cancer 2004. © 2004 American Cancer Society. [source] | ||||||||||