Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising

BACKGROUND: Post-sternotomy mediastinitis (PSM) is a devastating surgical complication affecting 1–3% of patients that undergo cardiac surgery. Staphylococcus aureus is one of the most commonly encountered bacterial pathogen cultured from mediastinal samples obtained from patients with PSM. A component of the membrane of the gram positive bacteria, lipoteichoic acid, stimulates the blood monocytes and macrophages to secrete cytokines, radicals and nitrogen species leading to oxido-inflammatory damage. This seems to be responsible for the high mortality rate in PSM. For the evaluation of the pathogenesis of infection or for the investigation of alternative treatment models in infection, no standard model of mediastinitis seems to be available. In this study, we evaluated four mediastinitis models in rats. METHODS: The rats were divided into four groups to form different infection models. Group A: A suspension of 1 × 10(7 )colony-forming units Staphylococcus aureus in 0,5 mL was inoculated from the right second intercostal space into the mediastinum. Group B: A hole was created in the right second intercostal space and a piece of stainless-steel implant with a length of 0.5 cm was inserted into the mediastinum and a suspension of 1 × 10(7 )cfu bacteria in 0,5 mL was administered via the tail vein. Group C: Precolonized stainless-steel implant was inserted into the mediastinum. Group D: Precolonized stainless-steel implant was inserted into the mediastinum and the bacteria suspension was also injected into the mediastinum. On the 10(th )day, rats were sacrificed and the extension of infection in the mediastenae was evaluated by quantitative cultures. Myeloperoxidase activity (MPO) and malondialdehyde (MDA) levels were determined in the sera to evaluate the neutrophil activation and assess the inflammatory oxidation. RESULTS: The degree of infection in group C and D were 83.3% and 100% respectively (P < 0.001). MDA levels were significantly higher in these two groups than the others (P < 0.001). CONCLUSION: Infected implants and high bacterial concentration administration were the two important components that played a significant role in the outcome of a successful infection in mediastinum in a rat model

Dynamic probability control limits for CUSUM charts for monitoring proportions with time-varying sample sizes

AYTACOGLU, BURCU/0000-0002-7164-9240WOS: 000499596700001We consider the problem of monitoring a proportion with time-varying sample sizes. Control charts are generally designed by assuming a fixed sample size or a priori knowledge of a sample size probability distribution. Sometimes, it is not possible to know, or accurately estimate, a sample size distribution or the distribution may change over time. An improper assumption for the sample size distribution could lead to undesirable performance of the control chart. To handle this problem, we propose the use of dynamic probability control limits (DPCLs) which are determined successively as the sample sizes become known. the method is based on keeping the conditional probability of a false alarm at a predetermined level given that there has not been any earlier false alarm. the control limits dynamically change, and the in-control performance of the chart can be controlled at the desired level for any sequence of sample sizes. the simulation results support this result showing that there is no need for any assumption of a sample size distribution with the use of this proposed approach

A Robust Control Chart for Monitoring the Mean of an Autocorrelated Process

WOS: 000352721400010Residual control charts are frequently used for monitoring autocorrelated processes. In the design of a residual control chart, values of the true process parameters are often estimated from a reference sample of in-control observations by using least squares (LS) estimators. We propose a robust control chart for autocorrelated data by using Modified Maximum Likelihood (MML) estimators in constructing a residual control chart. Average run length (ARL) is simulated for the proposed chart when the underlying process is AR(1). The results show the superiority of the new chart under several situations. Moreover, the chart is robust to plausible deviations from assumed distribution of errors

Controlling the conditional false alarm rate for the MEWMA control chart

An integral part of the design of control charts, including the multivariate exponentially weighted moving average (MEWMA) control chart, is the determination of the appropriate control limits for prospective monitoring. Methods using Markov chain analyses, integral equations, and simulation have been proposed to determine the MEWMA chart limits when the limits are based on a specified in-control average run length (ARL) value. A drawback of the usual approach is that the conditional false alarm rate (CFAR) for these charts varies over time in what might be in an unexpected and undesirable way. We define the CFAR as the probability of a false alarm given no previous false alarm. We do not condition on the results of a Phase I sample, as done by others, in studies of the effect of estimation error on control chart performance. We propose the use of dynamic probability control limits (DPCLs) to keep the CFAR constant over time at a specified value. The CFAR at any time, however, could be controlled to be any specified value using our approach. Using simulation, we determine the DPCLs for the MEWMA control chart being used to monitor the mean vector with an assumed known variance-covariance matrix. We consider cases where the sample size is both fixed and time-varying. For varying sample sizes, the DPCLs adapt automatically to any change in the sample size distribution. In all cases, the CFAR is held closely to a fixed value and the resulting in-control run length performance follows closely to that of the geometric distribution

Decreased serum total antioxidant status and erythrocyte-reduced glutathione levels are associated with increased serum malondialdehyde in atherosclerotic patients

PubMedID: 12031630Background. Coronary artery disease is the significant cause of morbidity and mortality today. The treatment of coronary artery disease is improving, but its prevalence is increasing. Both primary and secondary prevention measures are of vital importance. Methods. In this study, vitamin C, total antioxidant status, malondialdehyde in serum and erythrocyte-reduced glutathione levels were investigated in patients with atherosclerosis and compared with those of controls. Levels of serum MDA, vitamin C, total antioxidant status, and erythrocyte-reduced glutathione were determined according to the methods of Yagi, Bauer et al., Miller et al., and Beutler, respectively. Results. Erythrocyte-reduced glutathione, serum vitamin C, total antioxidant status, and malondialdehyde values of both patients with atherosclerosis and controls were as follows: 2.80±0.76, 5.82±0.67 µmol GSH/g Hb; 1.00±0.19, 1.62±0.30 mg/dL; 0.86±0.14, 1.43±0.16 mmol/L, and 4.26±0.9, 1.02±0.80 nmol/mL, respectively. There was a decrease in the levels of serum vitamin C, erythrocyte-reduced glutathione, and total antioxidant status (p<0.001), and increase in the levels of serum malondialdehyde (p<0.001) in patients with atherosclerosis when compared with those of controls. Conclusions. Because treatment of atherosclerosis is improving, our results suggest that antioxidant agents may have preventive roles in the formation of atherosclerosis. © 2002 IMSS. Published by Elsevier Science Inc

Effects of trimetazidine on tissue damage in kidney after hindlimb ischemia-reperfusion

WOS: 000178881300008PubMed ID: 12361697The objective of this study was to investigate the effects of trimetazidine (TMZ) on tissue damage in kidney after hindlimb ischemia-reperfusion (I/R), by assessing blood biochemical assay and histopathological analysis. Adult male Wistar rats were divided into two groups. TMZ 10 mg kg(-1) day(-1) was administrated twice a day for 10 days to the treatment group (group T, n = 10). Sham group was given only 5% gum arabic (group S, n = 10). On 11th day of treatment, 8 h I/R period was performed on right hindlimb of the rats. At the end of reperfusion period, a 5 ml blood withdrawn from ascending aorta for biochemical assays and their right kidneys were harvested for histopathological examination. Superoxide dismutase, Na+-K+ ATPase, and reduced glutathione levels were significantly increased in group T (P < 0.001). On the other hand, myeloperoxidase and malondialdehyde levels were significantly less in group T than group S (P < 0.001). Kidneys from the sham-operated group displayed intense leukocytic infiltration in histopathological examination. These overall results strongly suggested that TMZ contributes renal protection from hindlimb I/R injury by decreasing systemic oxidative stress. (C) 2002 Elsevier Science Ltd. All rights reserved

Evaluation of CNTNAP2 gene rs2107856 polymorphism in Turkish population with pseudoexfoliation syndrome

Meeting of the Turkish-Ophthalmology-Society -- 2016 -- Antalya, TURKEYWOS: 000460077900018PubMed ID: 29260496PurposeTo investigate rs2107856 single-nucleotide polymorphism (SNP) of CNTNAP2 gene in Turkish population with pseudoexfoliation and to correlate clinical characteristics with the genotypic profile.Materials and methodsForty-three patients with pseudoexfoliation syndrome (PXS), 46 patients with pseudoexfoliation glaucoma (PXG) and 99 healthy controls were enrolled. Comprehensive ophthalmological examination, central corneal thickness measurement and retinal nerve fiber layer thickness analysis of the peripapillary area were performed. Blood samples of 2mL with EDTA were obtained and sent for genetic analysis. The role of the detected polymorphism on disease tendency along with the genotype and allele frequencies in each group was evaluated.ResultsThe mean age of the groups was 70.08.0 (range 51-86) in PXS, 71.2 +/- 8.8 (range 51-93) in PXG and 64.6 +/- 8.3 (range 51-91) in controls. The percentages of homozygote individuals were 11.6, 10.9, 21.2%, and heterozygote individuals were 41.9, 45.7, 42.4% in patients with PXS, PXG and controls, respectively. There was no statistically significant difference between groups in terms of both genotype and allele frequencies of rs2107856 (p=0.429 and p=0.178, respectively). Retinal nerve fiber layer thickness did not differ between SNP-positive and SNP-negative individuals in PXG, and there was no significant difference between genotype and age, sex, best corrected visual acuity, intraocular pressure, central corneal thickness, cup/disk ratio and retinal nerve fiber layer thickness in any of the groups (p>0.05).Conclusion rs2107856 SNP of CNTNAP2 gene has no association with PXS and PXG in the evaluated Turkish population.Turkish Ophthalmol SocScientific Research Foundation of Ege University School of Medicine [2014-TIP-080]This research was supported by Scientific Research Foundation of Ege University School of Medicine (2014-TIP-080)