93 research outputs found
About temperature dependency of surface tensions in mixtures of lecithin in 3-hydroxypropionitrile
No full textThe surface tension temperature dependency of lecithin in 3-hydroxypropionitrile (3-HPN) was studied by means of the BP-2 bubble pressure tensiometer developed by KRUESS. The dynamic surface tension curves of dilute. lecithin solutions show a surprising temperature dependency within the range of 5-40 degreesC at 5 degreesC intervals and an "inversion point" was noticed. At higher concentrations of lecithin the observed inversion point disappears. The surface tensions recorded for long time periods are in agreement with selected data determined by means of the Wilhelmy plate method. The. dynamic surface tensions at 50 s were fitted by the general exponential function y =A exp (-x/ b) + c with x as the concentration. The obtained parameter b hereby equals the concentration intersection. point of the asymptotes ( x and x --> 0) and yields the value of the; critical aggregation concentration:. (cac). The strong linear temperature dependency of the determined cac values within the range of 0.22 mmol/kg (5 degreesC) to 0.716 mmol/ kg (40 degreesC) is remarkable. Diffusion coefficients of the dilute solutions were calculated by the Ward and Tordai equation. assuming a diffusion controlled adsorption mechanism. Similar to the determined surface tensions at 50 s, the diffusion coefficients of the dilute solutions show itself an unusual temperature dependency. This may support the assumption of a change in orientation of the lecithin lipid at the surface. Above the cac the temperature dependency of the diffusion coefficient follows the general Arrhenius law. The calculated molar fractions and absolute amounts of lecithin on the surface show an expected temperature dependency [1] in distinction of the surface excess amounts
Periodontal therapy and treatment of hypertension-alternative to the pharmacological approach. A systematic review and meta-analysis
No full textAim: Quantitative comparison of the effects of intensive (IPT) or conventional (CPT) periodontal treatment on arterial blood pressure, endothelial function and inflammatory/metabolic biomarkers. Materials and methods: A systematic search was conducted to identify randomized controlled trials (RCT) of IPT (supra and subgingival instrumentation). Eight RCTs were included in the meta-analysis. Difference in change of systolic blood pressure (SBP) and diastolic blood pressure (DBP) before and after IPT or CPT were the primary outcomes. The secondary outcomes included: endothelial function and selected inflammatory/anti-inflammatory (CRP, IL-6, IL-10, IFN-γ) and metabolic biomarkers (HDL, LDL, TGs). Results: The overall effect estimates (pooled Weighted Mean Difference (WMD)) of the primary outcome for SBP and DBP was −4.3 mmHg [95%CI: −9.10–0.48], p = 0.08 and −3.16 mmHg [95%CI: −6.51–0.19], p = 0.06 respectively. These studies were characterized by high heterogeneity. Therefore, random effects model for meta-analysis was performed. Sub-group analyses confirmed statistically significant reduction in SBP [WMD = −11.41 mmHg (95%CI: −13.66, −9.15) P < 0.00001] and DBP [WMD = −8.43 mmHg (95%CI: −10.96,−5.91)P < 0.00001] after IPT vs CPT among prehypertensive/hypertensive patients, while this was not observed in normotensive individuals. The meta-analyses showed significant reductions in CRP and improvement of endothelial function following IPT at all analysed timepoints. Conclusions: IPT leads to improvement of the cardiovascular health in hypertensive and prehypertensive individuals
The relationship between anti-mullerian hormone in women receiving fertility assessments and age at menopause in subfertile women: evidence from large population studies
No full text<p>Context: Anti-Müllerian hormone (AMH) concentration reflects ovarian aging and is argued to be a useful predictor of age at menopause (AMP). It is hypothesized that AMH falling below a critical threshold corresponds to follicle depletion, which results in menopause. With this threshold, theoretical predictions of AMP can be made. Comparisons of such predictions with observed AMP from population studies support the role for AMH as a forecaster of menopause.</p>
<p>Objective: The objective of the study was to investigate whether previous relationships between AMH and AMP are valid using a much larger data set.</p>
<p>Setting: AMH was measured in 27 563 women attending fertility clinics.</p>
<p>Study Design: From these data a model of age-related AMH change was constructed using a robust regression analysis. Data on AMP from subfertile women were obtained from the population-based Prospect-European Prospective Investigation into Cancer and Nutrition (Prospect-EPIC) cohort (n = 2249). By constructing a probability distribution of age at which AMH falls below a critical threshold and fitting this to Prospect-EPIC menopausal age data using maximum likelihood, such a threshold was estimated.</p>
<p>Main Outcome: The main outcome was conformity between observed and predicted AMP.</p>
<p>Results: To get a distribution of AMH-predicted AMP that fit the Prospect-EPIC data, we found the critical AMH threshold should vary among women in such a way that women with low age-specific AMH would have lower thresholds, whereas women with high age-specific AMH would have higher thresholds (mean 0.075 ng/mL; interquartile range 0.038–0.15 ng/mL). Such a varying AMH threshold for menopause is a novel and biologically plausible finding. AMH became undetectable (<0.2 ng/mL) approximately 5 years before the occurrence of menopause, in line with a previous report.</p>
<p>Conclusions: The conformity of the observed and predicted distributions of AMP supports the hypothesis that declining population averages of AMH are associated with menopause, making AMH an excellent candidate biomarker for AMP prediction. Further research will help establish the accuracy of AMH levels to predict AMP within individuals.</p>
Sparse kernel methods for high-dimensional survival data
No full textSparse kernel methods like support vector machines (SVM) have been applied with great success to classification and (standard) regression settings. Existing support vector classification and regression techniques however are not suitable for partly censored survival data, which are typically analysed using Cox's proportional hazards model. As the partial likelihood of the proportional hazards model only depends on the covariates through inner products, it can be ‘kernelized’. The kernelized proportional hazards model however yields a solution that is dense, i.e. the solution depends on all observations. One of the key features of an SVM is that it yields a sparse solution, depending only on a small fraction of the training data. We propose two methods. One is based on a geometric idea, where—akin to support vector classification—the margin between the failed observation and the observations currently at risk is maximised. The other approach is based on obtaining a sparse model by adding observations one after another akin to the Import Vector Machine (IVM). Data examples studied suggest that both methods can outperform competing approaches
Cyclosporin variably and inconsistently reduces infarct size in experimental models of reperfused myocardial infarction: a systematic review and meta-analysis
No full textCyclosporin is an immunosuppressant that has recently been proposed as a treatment to prevent reperfusion injury in acute myocardial infarction (MI). We aimed to determine the overall efficacy of cyclosporin in experimental studies of acute reperfused MI. We conducted a systematic review and stratified meta-analysis of published studies describing the efficacy of cyclosporin in experimental models of acute reperfused MI. We included all in vivo publications of cyclosporin where infarct size was measured. A literature search identified 29 potential studies of which 20 fulfilled the eligibility criteria. In these studies (involving four species of animals), cyclosporin reduced myocardial infarct size by a standardized mean (95% confidence interval) difference of −1.60 (−2.17, −1.03) compared with controls. Cyclosporin failed to demonstrate a convincing benefit in studies involving pigs. Despite this observation, the overall efficacy of cyclosporin did not differ across species (P= 0.358). The dose of cyclosporin given did not affect final infarct size (P= 0.203). Funnel plots of these data suggested heterogeneity among the studies. Cyclosporin had variable effects on infarct size compared with placebo. Cyclosporin had no effect on myocardial infarct size in swine, raising a question over the potential cardioprotective effects of cyclosporin in man
The feasibility of screening for and treating vitamin D deficiency in forensic psychiatric inpatients
No full textNeuroleptic and antiepileptic medication, inadequate vitamin D intake and limited solar
exposure increase the risk of vitamin D deficiency in high security psychiatric environments. Of the 33
inpatients (40% selected; 21% of hospital population) completing this cross-sectional study, 36% had
insufficient and 58% deficient vitamin D. Five patients with vitamin D deficiency had secondary
hyperparathyroidism, two of whom had osteopenia on dual-emission x-ray absorptiometry. At 1 year
follow up, of the 31 patients eligible, 15 had accepted and continued supplements. Systematic
screening is therefore necessary due to mental health and consent issues. Implications of
supplementation and grounds access are discussed
How to define a Minimal Clinically Individual state (MCIS) with pain VAS in daily practice for patients suffering from musculoskeletal disorders
No full text<p><b>OBJECTIVES:</b> Pain is frequently the primary variable in symptomatic clinical trials for the evaluation of rheumatological disorders. The protocol of such trials mention a minimum level of pain as an entry criterion [e.g. a level above the Patient Acceptable Symptoms State (PASS)] and the changes in pain as the primary variable. Usually, the results are expressed at a group level as the mean changes in pain. However, the presentation at an individual level and, in particular, the percentage of patients with a Low Disease Activity State at the end of the study seems more clinically relevant. Pain is usually evaluated using a continuous variable such as a 0-100 visual analogue scale. The cut-offs permitting one to define both the entry criterion and the LDAS are not well established. The objective of this study was to evaluate such cut-offs using a patient-derived perspective.</p>
<p><b>METHODS:</b> Study design: cross-sectional study. Patients: consecutive out patients suffering from chronic rheumatic diseases familiar with the use of a VAS to evaluate their level of pain. Data collected: two questions were asked the patients at the end of the visit: "Based on the experience you have because of your chronic rheumatic disorder, could you please specify the level of pain below which you consider your disease as inactive ? Moreover, could you please also specify the level of pain above which you consider taking a pain killer?" Before answering the second question, it was explained to the patient that their answer to the second question could be similar to their response to the first one. For the two questions, the cumulative percentage of patients (disease inactive and pain killer intake) were calculated for each level of pain.</p>
<p><b>RESULTS:</b> The underlying disease of the 137 evaluated patients (mean age: 57+/-16 and female sex: 76%) was rheumatoid arthritis (n = 59), ankylosing spondylitis (n = 19), SLE (n = 2), back pain (n = 20), or peripheral osteoarthritis (n = 37). The mean disease duration was 12+/-10 years. At the time of the study, the current level of pain evaluated on a 0-100 VAS was 33+/-22. The LDAS was 49, 36 and 25 for our patient population at the 25th, 50th and 75th percentiles, respectively. The pain killer intake level was 32, 48, 64 at the 25th, 50th, 75th percentile respectively.</p>
<p><b>CONCLUSION:</b> This study suggests that LDAS and PASS may be distinct concepts. The methodological approach adopted here could be of interest for specifying the minimum level of symptoms at entry in a symptomatic trial (PASS) and also to present results in terms of the percentage of patients in good condition (LDAS) at the end of a trial.</p>
Cystatin C and cardiovascular mortality in patients with coronary artery disease and normal or mildly reduced kidney function: results from the AtheroGene study
No full textChronic kidney disease is associated with increased risk of cardiovascular disease. Cystatin C is a promising marker to reliably mirror renal function. The role of cystatin C in patients with coronary artery disease (CAD) and normal or mildly reduced kidney function is the subject of current investigation.
In 2162 patients, over the whole spectrum of CAD, baseline cystatin C concentrations were measured. Patients with an estimated glomerular filtration rate of ≤ 60 mL/min per 1.73 m(2) (n = 295) were excluded. In patients with complete follow-up information (n = 1827), 66 cardiovascular deaths were registered during a median follow-up of 3.65 years. Logarithmically transformed, standardized cystatin C was associated with cardiovascular death [hazard ratio: 1.94, 95% confidence interval (CI): 1.59-2.37, P < 0.001]. A potential threshold effect was observed; patients in the upper quartile had a 3.87-fold (95% CI: 2.33-6.42; P < 0.001) risk of mortality compared with the pooled lower quartiles. This risk association remained robust after adjustment for potential confounders including classical risk factors and N-terminal pro B-type natriuretic peptide. Serum creatinine was not associated with the outcome in this group of patients with normal renal function.
Results of this prospective study show that cystatin C is a potent predictor of cardiovascular mortality beyond classical risk factors in patients with CAD and normal or mildly reduced kidney function
Assessment of fatigue in the management of patients with ankylosing spondylitis
No full textBACKGROUND: Pain, stiffness, functional impairment, range of motion and quality of life are the main conventional domains used in studies evaluating ankylosing spondylitis (AS). However, fatigue has been reported as the major complaint of AS patients.
OBJECTIVES: To evaluate fatigue as a potential independent domain in comparison with the 'conventional' ones and to evaluate the sensitivity to change after non-steroidal anti-inflammatory drug (NSAID) therapy.
METHODS: Patients were classified as having painful AS (modified New York criteria). The following variables were recorded at baseline and after 6 weeks of therapy (either placebo or NSAIDs): pain (VAS), function (Bath Ankylosing Spondylitis Functional Index), patient's global assessment (VAS), inflammation (night pain), morning stiffness, metrology (Schober test, finger-to-floor) and fatigue using 0-100 VAS scale. Analysis consisted of (i) the prevalence of fatigue (VAS value of at least 50 mm), (ii) the independence of the information evaluated using a regression model, and (iii) the sensitivity to change, by calculating the standardized response mean (mean change/s.d. change) (SRM) between placebo and NSAID group.
RESULTS: Fatigue was considered important in 401 patients (out of 639: 63%). The information provided by the variables 'pain', 'function' and 'global assessment' explained only 44% of the variability of the variable 'fatigue' (similar analyses considering 'pain' on the one hand and 'function' on the other hand as the dependent variables showed an R2 value of 34 and 60%, respectively). The NSAID treatment effect (SRM) was higher for the variables 'pain' and 'function' (0.76 and 0.71, respectively) than for the variable 'fatigue' (0.34).
CONCLUSION: This study strongly suggests that fatigue should be considered as an independent domain to be systematically evaluated in AS patients and that conventional therapy such as NSAIDs have a lower effect on this domain than on pain or functional impairment
Bedeutung des präoperativen C-reaktiven Proteins für die Prognose beim Ösophaguskarzinom
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