Monte Carlo Optimization Method Based QSAR Modeling of Placental Barrier Permeability.

PURPOSE: In order to ensure that drug administration is safe during pregnancy, it is crucial to have the possibility to predict the placental permeability of drugs in humans. The experimental method which is most widely used for the said purpose is in vitro human placental perfusion, though the approach is highly expensive and time consuming. Quantitative structure-activity relationship (QSAR) modeling represents a powerful tool for the assessment of the drug placental transfer, and can be successfully employed to be an alternative in in vitro experiments. METHODS: The conformation-independent QSAR models covered in the present study were developed through the use of the SMILES notation descriptors and local molecular graph invariants. What is more, the Monte Carlo optimization method, was used in the test sets and the training sets as the model developer with three independent molecular splits. RESULTS: A range of different statistical parameters was used to validate the developed QSAR model, including the standard error of estimation, mean absolute error, root-mean-square error (RMSE), correlation coefficient, cross-validated correlation coefficient, Fisher ratio, MAE-based metrics and the correlation ideality index. Once the mentioned statistical methods were employed, an excellent predictive potential and robustness of the developed QSAR model was demonstrated. In addition, the molecular fragments, which are derived from the SMILES notation descriptors accounting for the decrease or increase in the investigated activity, were revealed. CONCLUSION: The presented QSAR modeling can be an invaluable tool for the high-throughput screening of the placental permeability of drugs.

Supporting Pharmacovigilance Signal Validation and Prioritization with Analyses of Routinely Collected Health Data: Lessons Learned from an EHDEN Network Study.

INTRODUCTION: Individual case reports are the main asset in pharmacovigilance signal management. Signal validation is the first stage after signal detection and aims to determine if there is sufficient evidence to justify further assessment. Throughout signal management, a prioritization of signals is continually made. Routinely collected health data can provide relevant contextual information but are primarily used at a later stage in pharmacoepidemiological studies to assess communicated signals. OBJECTIVE: The aim of this study was to examine the feasibility and utility of analysing routine health data from a multinational distributed network to support signal validation and prioritization and to reflect on key user requirements for these analyses to become an integral part of this process. METHODS: Statistical signal detection was performed in VigiBase, the WHO global database of individual case safety reports, targeting generic manufacturer drugs and 16 prespecified adverse events. During a 5-day study-a-thon, signal validation and prioritization were performed using information from VigiBase, regulatory documents and the scientific literature alongside descriptive analyses of routine health data from 10 partners of the European Health Data and Evidence Network (EHDEN). Databases included in the study were from the UK, Spain, Norway, the Netherlands and Serbia, capturing records from primary care and/or hospitals. RESULTS: Ninety-five statistical signals were subjected to signal validation, of which eight were considered for descriptive analyses in the routine health data. Design, execution and interpretation of results from these analyses took up to a few hours for each signal (of which 15-60 minutes were for execution) and informed decisions for five out of eight signals. The impact of insights from the routine health data varied and included possible alternative explanations, potential public health and clinical impact and feasibility of follow-up pharmacoepidemiological studies. Three signals were selected for signal assessment, two of these decisions were supported by insights from the routine health data. Standardization of analytical code, availability of adverse event phenotypes including bridges between different source vocabularies, and governance around the access and use of routine health data were identified as important aspects for future development. CONCLUSIONS: Analyses of routine health data from a distributed network to support signal validation and prioritization are feasible in the given time limits and can inform decision making. The cost-benefit of integrating these analyses at this stage of signal management requires further research.

Monitoring the Coagulation Profile of COVID-19 Patients Using Standard and ClotPro® Hemostasis Tests.

Background and Objectives: Coagulation disorders during COVID-19 infection are associated with a poorer prognosis and higher disease severity because thrombosis and inflammation are two processes that interfere with each other. A very important issue for clinicians is timely and adequate hemostasis and inflammation monitoring to prevent and treat potentially lethal consequences. The aim of this study was to identify specific hemostatic parameters that are associated with a higher risk of intrahospital mortality. Materials and Methods: This study was approved by the Ethics Committee of the Clinical Center Nis in Serbia. One hundred and forty-two patients presented with COVID-19 ARDS and were admitted to the ICU in the Clinic for Anesthesiology at the Clinical Center Nis from 14 April 2020 to 25 May 2020. Upon admission, blood was collected for biochemical and coagulation testing. The data obtained were analyzed using the Statistical Package for Social Sciences (SPSS v. 25, Chicago, IL, USA). Results: Among all the parameters assessed, older age; increased levels of fibrinogen, INR, D-dimer, and presepsin; and higher results in the platelet aggregation tests (aggregation induced by adenosine diphosphate based on the ADP test (AU/min), aggregation induced by arachidonic acid based on the ASPI test (AU/min), and aggregation induced by thrombin based on the TRAP test (AU/min)) and some assays of the viscoelastic test (clot amplitude after 5 min in the extrinsic coagulation pathway based on the A5 EX-test (mm), clot amplitude after 10 min in the extrinsic coagulation pathway based on the A10 EX-test (mm), clot amplitude after 5 min regarding functional fibrinogen based on the A5 FIB-test (mm), clot amplitude after 10 min regarding functional fibrinogen based on the A10 FIB-test (mm), and maximum clot firmness based on the MCF FIB-test (mm)); and lower values of viscoelastic clotting time in the extrinsic coagulation pathway based on the CT EX-test (s) were significantly correlated with mortality. In the multivariate analysis, D-dimer levels above 860 ng/mL, higher TRAP test value bins, and values above the normal reference range of the A10 FIB test were found to be independent predictors of mortality. Conclusions: Sophisticated hemostasis parameters can contribute to early risk assessment, which has initially been performed only on the basis of patients' clinical status. Hypercoagulability is the main coagulation disorder in COVID-19 infection.

The influence of different sub-bandage pressure values in the prevention of recurrence of venous ulceration-A ten year follow-up.

OBJECTIVE: The aim of this study was to establish the efficacy of three different strengths of compression systems in the prevention of venous leg ulcer (VLU) recurrences during a 10-year follow up period. METHODS: An open, prospective, randomized, single-center study included 477 patients (240 men, 237 women; mean age 59 years). Patients were randomized into three groups: Group A) 149 patients (allocated to wear elastic stocking 18-25 mmHg). Group B) 167 patients (wearing compression device exerting 25-35 mmHg), and Group C) 161 patients (treated with multilayer compression system exerting 35-50 mmHg). RESULTS: Overall, 65% (234/360) of patients had recurrent VLU within 10 years. Recurrence occurred in 120 (96%) of 125 in group A, in 89 (66.9%) of 133 patients in group B and in 25 (24.5%) of 102 patients in group C (p < 0.05). CONCLUSION: Compression systems with the higher compression class provide lower recurrence rate.

Melatonin as a Promising Anti-Inflammatory Agent in an In Vivo Animal Model of Sepsis-Induced Rat Liver Damage.

Melatonin (MLT), earlier described as an effective anti-inflammatory agent, could be a beneficial adjunctive drug for sepsis treatment. This study aimed to determine the effects of MLT application in lipopolysaccharide (LPS)-induced sepsis in Wistar rats by determining the levels of liver tissue pro-inflammatory cytokines (TNF-α, IL-6) and NF-κB as well as hematological parameters indicating the state of sepsis. Additionally, an immunohistological analysis of CD14 molecule expression was conducted. Our research demonstrated that treatment with MLT prevented an LPS-induced increase in pro-inflammatory cytokines TNF-α and IL-6 and NF-κB levels, and in the neutrophil to lymphocyte ratio (NLR). On the other hand, MLT prevented a decrease in the blood lymphocyte number induced by LPS administration. Also, treatment with MLT decreased the liver tissue expression of the CD14 molecule observed after sepsis induction. In summary, in rats with LPS-induced sepsis, MLT was shown to be a significant anti-inflammatory agent with the potential to change the liver's immunological marker expression, thus ameliorating liver function.

Melatonin arrests excessive inflammatory response and apoptosis in lipopolysaccharide-damaged rat liver: A deeper insight into its mechanism of action.

Sepsis is a life-threatening organ dysfunction. An animal model mimicking sepsis utilizes lipopolysaccharide (LPS), an endotoxin recognized as the most potent bacterial mediator of sepsis. Melatonin (MLT), an effective anti-inflammatory and antioxidant agent, is a promising adjunctive drug for sepsis. This study aimed to estimate the potential of MLT in preventing LPS-induced liver damage in Wistar rats by determining the levels of serum and tissue biochemical markers that reflect liver state and function, i.e., serum levels of transaminases and albumin, as well as a panel of oxidative stress-related biomarkers. Additionally, a pathohistological analysis of liver tissue was conducted. Pre-treatment with MLT prevented an LPS-induced increase in serum and tissue liver damage markers and a decrease in the tissue antioxidant capacity, in both enzymatic and non-enzymatic systems. Micromorphological liver tissue changes mirrored the alterations observed in the biochemical status. In rats with LPS-induced sepsis, melatonin was shown to be a crucial antioxidant and anti-inflammatory agent, with vital roles in the alleviation of oxidative stress, causing an increase of the antioxidant capacities and the improvement of the liver's microscopic appearance.

Platelet thrombus formation in patients with end-stage renal disease before and after hemodialysis as measured by the total thrombus-formation analysis system.

BACKGROUND: Patients with end-stage renal disease (ESRD) receiving hemodialysis (HD) often experience bleeding. However, mechanisms behind this bleeding tendency are incompletely understood but may involve platelet dysfunction. We, therefore, studied platelet-dependent thrombus formation in flowing whole blood inside a microchip coated with collagen, and its association with circulating von Willebrand factor (VWF). METHODS: Blood samples were obtained in 22 patients before and after HD. The area under the 10 min flow pressure curve in a microchip (AUC10) reflecting total platelet thrombogenicity was measured, using the Total Thrombus-formation Analysis System (T-TAS01). AUC10 < 260 indicates platelet dysfunction. VWF activity and antigen in plasma were also assayed. RESULTS: VWF levels were moderately elevated and increased further after HD (P < 0.01 or lower). In contrast, AUC10 before and after HD was < 260 in 17/22 patients and < 130 in 15/22 patients, with no statistically significant difference in pre- vs post-HD measurements, indicating reduced platelet thrombogenicity, but with some variability as 5/22 patients showed normal platelet responsiveness. AUC10 and VWF activity or antigen levels in plasma were not correlated, either before or after HD. CONCLUSIONS: Most ESRD patients display moderate-to-severe platelet dysfunction as assessed by shear-induced platelet-dependent thrombus formation with T-TAS01. HD does not influence platelet function despite HD-induced elevations in VWF. T-TAS01 should be further evaluated as a tool in the assessment of bleeding risk in patients on HD.

Health crisis: What opportunities for clinical drug research?

The COVID-19 pandemic led to the deployment of an unprecedented academic and industrial research effort, the sometimes redundant nature of which is regrettable, as is the lack of both national and international management. However, it must be noted that during this crisis, regulatory procedures were adapted and certain obstacles in the organisation of clinical research were partly removed to contribute to the deployment of trials as close as possible to patients and to facilitate monitoring and control procedures. The digitisation of certain processes and the decentralisation of certain activities were implemented under the cover of a mobilisation of the authorities and all institutional, academic and industrial players. While in the UK, the optimisation of resources through a single platform trial has made it possible to demonstrate or invalidate the efficacy of many treatments, in France the health crisis has highlighted the fragility of the organisation of clinical research, in particular a lack of coordination and funding, difficulties in implementing studies and a certain reluctance to share data. However, the crisis has also revealed the adaptability of the various stakeholders and has led to the improvement of several processes useful for the deployment of therapeutic innovation. Let us hope that the lessons learned during this crisis will allow for greater efficiency in the event of a new pandemic and, above all, that the progress made will continue to apply to all future clinical research activities.

Predictive potential of biomarkers and risk scores for major adverse cardiac events in elderly patients undergoing major elective vascular surgery.

Elderly patients scheduled for major elective vascular surgery are at high risk for a major adverse cardiac events (MACE). The objectives of the study were: (1) To determine the individual discriminatory ability of four risk prediction models and four biomarkers in predicting MACEs in elderly patients undergoing major elective vascular surgery; (2) to find a prognostic model with the best characteristics; (3) to examine the significance of all preoperative parameters; and (4) to determine optimal cut-off values for biomarkers with best predictor capabilities. We enrolled 144 geriatric patients, aged 69.97 ± 3.73 years, with a 2:1 male to female ratio. Essential inclusion criteria were open major vascular surgery and age >65 years. The primary outcome was the appearance of MACEs within 6 months. These were noted in 33 (22.9%) patients. The most frequent cardiac event was decompensated heart failure, which occurred in 22 patients (15.3%). New onset atrial fibrillation was registered in 13 patients (9%), and both myocardial infarction and ventricular arrhythmias occurred in eight patients each (5.5%). Excellent discriminatory ability (AUC >0.8) was observed for all biomarker combinations that included the N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP). The most predictive two-variable combination was the Geriatric-Sensitive Cardiac Risk Index (GSCRI) + NT-proBNP (AUC of 0.830 with a 95% confidence interval). Female gender, previous coronary artery disease, and NT-proBNP were three independent predictors in a multivariate model of binary logistic regression. The Cox regression multivariate model identified high-sensitivity C-reactive protein and NT-proBNP as the only two independent predictors.

In silico development of potential therapeutic for the pain treatment by inhibiting voltage-gated sodium channel 1.7.

The voltage-gated sodium channel Nav1.7 can be considered as a promising target for the treatment of pain. This research presents conformational-independent and 3D field-based QSAR modeling for a series of aryl sulfonamide acting as Nav1.7 inhibitors. As descriptors used for building conformation-independent QSAR models, SMILES notation and local invariants of the molecular graph were used with the Monte Carlo optimization method as a model developer. Different statistical methods, including the index of ideality of correlation, were used to test the quality of the developed models, robustness and predictability and obtained results were good. Obtained results indicate that there is a very good correlation between 3D QSAR and conformation-independent models. Molecular fragments that account for the increase/decrease of a studied activity were defined and used for the computer-aided design of new compounds as potential analgesics. The final evaluation of the developed QSAR models and designed inhibitors were carried out using molecular docking studies, bringing to light an excellent correlation with the QSAR modeling results.

Preoperative Levels of the Soluble Urokinase-Type Plasminogen Activator Receptor as Predictor for New Episodes of Atrial Fibrillation After Vascular Surgery.

INTRODUCTION: The soluble urokinase-type plasminogen activator receptor (suPAR) in uPAR soluble form is produced when the uPAR is cleaved from the cell membrane during the inflammatory process. Postoperative atrial fibrillation (AF) is the most common perioperative cardiac arrhythmia. It is speculated that elevated suPAR has a role in the development of AF. The aim of our study was to investigate the predictive role of preoperative suPAR in the occurrence of AF during the first 6 months after major vascular surgery. METHODS: We included 119 male and 63 female patients with an average age of 67.19 ± 6.02 years, without permanent/persistent AF. Basic predictive model (BASIC) included traditional risk factors for AF: age, gender, body mass index-BMI, smoking status, presence of arterial hypertension, diabetes mellitus and dyslipidemia. RESULTS: Over the 6-month period, 19 (10.4%) patients had one new episode of atrial fibrillation and 2 patients (1.1%) had 2 episodes of paroxysmal atrial fibrillation. Paroxysms of AF were significantly more frequent in patients who had a resection of an abdominal aneurysm than in patients with other types of major vascular surgery. BASIC had good discriminatory ability in the prediction of AF paroxysms during the first 6 months after surgery (AUC = 0.715, 95%CI 0.590-0.840). Adding suPAR to the basic model significantly improved the discriminative ability of the predictive model for AF episodes (ΔAUC = 0.238, p < 0.001). The predictive performance of the model BASIC+CRP+suPAR, measured using AUC, NRI and IDI statistics, was very similar to the model BASIC+suPAR. CONCLUSION: AF is a common complication in surgical patients with high mortality and morbidity. suPAR could improve the ability of traditional risk factors to predict its occurrence up to 6 months after major vascular surgery.

Correlation between climatic and biochemical parameters in etiopathogenesis of unprovoked deep vein thrombosis of the lower limbs.

AIM: Beside the intention of early detection and optimal treatment of deep venous thrombosis (DVT), the aim of this study was to investigate the influence of chronobiological rhythms on the etiopathogenesis of unprovoked deep vein thrombosis of the lower limbs with monitoring of seasonal variations in biochemical parameters. PATIENTS AND METHODOLOGY: The prospective clinical trial included all consecutive hospitalized patients and outpatients diagnosed with DVT at the Vascular Surgery Clinic of the Clinical Center in Nis, starting from January 2013 to December 2014. RESULTS: There was no statistically significant difference in correlation between the distribution of the incidence of DVT of the lower limbs (p = 0.582), sex (p = 0.350), age (p = 0.385) and localization (p = 0.886) and the seasons. Creatinine levels were significantly higher in patients who developed DVT in spring than in those who developed DVT in winter (p < 0.05), while LDL cholesterol levels were significantly higher in patients diagnosed with DVT in winter than in those diagnosed with DVT in autumn (p < 0.05). CONCLUSION: According to the results of the study, it can be concluded that in the territory of South Serbia, the seasons are not significantly related to the incidence, sex, age and localization of unprovoked DVT of the lower limbs. Creatinine levels were significantly higher in patients who developed DVT in spring than in those who developed DVT in winter, while LDL cholesterol levels were significantly higher in patients during winter than during autumn.

Underestimation tendencies of vehicle speed by pedestrians when crossing unmarked roadway.

To make safe road crossing decisions, the pedestrians need to estimate the distance and speed of oncoming vehicles, in order to make conclusions about the available time gap they need for their road crossing. Since the speed represents combination of distance and time, we focused on pedestrians' ability to estimate the speed of the oncoming vehicles accurately. The aim of this study was to find some characteristics important for the speed mis-estimation tendencies and its values. Seventy participants estimated speed 3920 times in total. Research included three experiments. One vehicle participated in the first experiment, while second and third experiments involved two vehicles, with various combinations of vehicle positions and speeds. Initially it was determined that the pedestrians had tendencies to speed underestimation rather than its overestimation and accurate estimation. When the participants estimated the speed of one vehicle, they were more inclined to underestimation of higher speeds (over 50 km/h). On the other hand, in the situations where the participants estimated the speed of two vehicles, they showed a serious tendency towards underestimation of lower speeds (under 50 km/h) which was completely opposite. The factors such as driving experience, age and gender were identified as statistically important in terms of speed underestimation value. We determined that an increase in task complexity, with introduction of a larger number of vehicles, resulted in more severe speed underestimation. Finally, we identified some of the most risky traffic situations in terms of speed underestimation tendencies showed by our participants.

Design and development of novel therapeutics for coronary heart disease treatment based on cholesteryl ester transfer protein inhibition - in silico approach.

Cholesteryl ester transfer protein (CETP) belongs to the group of enzymes which inhibition have the application in the treatment of cardiovascular diseases. This study presents QSAR modeling for a set of compounds acting as CETP inhibitors based on the Monte Carlo optimization with SMILES notation and molecular graph-based descriptors, and field-based 3D modeling. A 3D QSAR model was developed for one random split into the training and test sets, whereas conformation independent QSAR models were developed for three random splits, with the results suggesting there is an excellent correlation between them. Various statistical approaches were used to assess the statistical quality of the developed models, including robustness and predictability, and the obtained results were very good. This study used a novel statistical metric known as the index of ideality of correlation for the final assessment of the model, and the results that were obtained suggested that the model was good. Also, molecular fragments which account for the increases and/or decreases of a studied activity were defined and then used for the computer-aided design of new compounds as potential CETP inhibitors. The final assessment of the developed QSAR model and designed inhibitors was done using molecular docking, which revealed an excellent correlation with the results from QSAR modeling.Communicated by Ramaswamy H. Sarma.

Potential New Approaches in Predicting Adverse Cardiac Events One Month after Major Vascular Surgery.

OBJECTIVE: The aim of our study was to find the best model with sufficient power to improve the risk stratification in major vascular surgery patients during the first 30 days after this procedure. The discriminatory power of 4 biomarkers (troponin I [TnI], N-terminal prohormone of brain natriuretic peptide [NT-proBNP], creatine kinase-MB isoenzyme [CK-MB], high-sensitivity C-reactive protein [hs-CRP]) was tested as well as 2 risk assessment models and 13 different combinations of them. SUBJECTS AND METHODS: The study included 122 patients (77% men, 23% women) with an average age of 67.03 ± 4.5 years. An aortobifemoral bypass was performed in 6.56% of the patients, a femoropopliteal bypass in 18.85%, and 49.18% received open surgical reconstruction of the carotid arteries. A total of 25.41% of the patients were given an aortobi-iliac bypass. RESULTS: During the first 30 days, 13 patients (10.7%) had 17 cardiac complications. The most common complication was the new onset of atrial fibrillation (35.3%). During the first 10 days, 10 patients had 1 complication and 2 patients had 2 cardiac events, while 1 patient had 3 complications. By comparing combinations of scores and markers, it was shown that revised cardiac risk index (RCRI) + Vascular Portsmouth Physiological and Operative Severity Score (V-POSSUM) + hsTnI and RCRI + V-POSSUM + hsTnI + NT-proBNP with 100% sensitivity, > 80% specificity had the best discriminatory ability (AUC 0.924 and 0.933, respectively; p < 0.001 for both models) for cardiac complications during the 30 days after surgery. CONCLUSION: Combinations of traditional preoperative risk factors and scores can enhance the assessment of major adverse cardiac events (MACE) in patients preparing for large vascular surgery. Using only one risk score in these patients seems to be underperforming in preoperative risk assessment.

A Risk Stratification Model for Cardiovascular Complications during the 3-Month Period after Major Elective Vascular Surgery.

INTRODUCTION: The Revised Cardiac Risk Index (RCRI) is an extensively used simple risk stratification tool advocated by the European Society of Cardiology and European Society of Anesthesiology (ESC/ESA). PURPOSE: The aim of this study was to find the best model for predicting 3-month cardiovascular complications in elective major vascular surgical patients using preoperative clinical assessment, calculation of the RCRI and Vascular Physiological and Operative Severity Score for the enumeration of mortality and morbidity (V-POSSUM) scores, and the preoperative levels of N-terminal brain natriuretic peptide (NT pro-BNP), high-sensitivity troponin I (hs TnI), and high-sensitivity C-reactive protein (hs CRP). MATERIALS AND METHODS: We included 122 participants in a prospective, single-center, observational study. The levels of NT pro-BNP, hs CRP, and hs TnI were measured 48 hours prior to surgery. During the perioperative period and 90 days after surgery the following adverse cardiac events were recorded: myocardial infarction, arrhythmias, pulmonary edema, acute decompensated heart failure, and cardiac arrest. RESULTS: During the first 3 months after surgery 29 participants (23.8%) had 50 cardiac complications. There was a statistically significant difference in the RCRI score between participants with and without cardiac complications. ROC analysis showed that a combination of RCRI with hs TnI has good discriminatory power (AUC 0.909, p<0,001). By adding NT pro-BNP concentrations to the RCRI+hs TnI+V-POSSSUM combination we obtained the model with the best predictive power for 3-month cardiac complications (AUC 0.963, p<0,001). CONCLUSION: We need to improve preoperative risk assessment in participants scheduled for major vascular surgery by combining their clinical scores with biomarkers. Therefore, it is possible to identify patients at risk of cardiovascular complications who need adequate preoperative diagnosis and treatment.

A randomized trial of class 2 and class 3 elastic compression in the prevention of recurrence of venous ulceration.

BACKGROUND: Venous leg ulcers (VLUs) are a major health problem because of their high prevalence and associated high cost of care. Despite the widespread use of compression, treatment recurrence rates remain high. Numerous studies have suggested that regular use of compression stockings reduces VLU recurrences. However, there are limited data concerning how long compression hosiery should be worn after ulcer healing and which class of compression hosiery achieves better results in the prevention of VLU recurrences. METHODS: An open, prospective, randomized, single-center study with a 5-year follow-up was performed to establish the efficacy of two different strengths of knee-high compression hosiery (class 2 and class 3) in the prevention of VLU recurrences. The study included patients with recently healed venous ulcers and no significant arterial disease, rheumatoid disease, diabetes mellitus, and restriction in range of ankle movement. Overall, 361 patients were randomized, and 308 patients (170 men, 138 women; mean age, 59 years) completed the study. Patients were randomized into two groups: group A, 186 patients who wore a heel-less open-toed elastic class 3 compression device knitted in tubular form (Tubulcus; Laboratoires Innothera, Arcueil, France); and group B, 175 patients who wore a class 2 elastic stocking (Rudo, Nis, Serbia). All patients were instructed to wear compression stockings continuously for the first 2 years of follow-up (both during the day and at night). In the third, fourth, and fifth years of follow-up, patients were instructed to wear elastic stockings during the day only. The main outcome measures were recurrence of leg ulceration and compliance with the treatment. RESULTS: Rates of ulcer recurrence after the 5 years of follow-up were 28.98% for the compression class 3 group and 60% for the compression class 2 group (P < .001, log-rank test). Patients in the compression class 3 group experienced significantly longer absolute (46 vs 40 months; P < .001, Mann-Whitney U test) and proportional (77% vs 67%; P < .001, Mann-Whitney U test) ulcer-free time after 5 years than those in the compression class 2 group. Rates of noncompliance after 5 years were 10.23% for the compression class 3 group and 6.25% for the compression class 2 group (P = .188, χ2 test). CONCLUSIONS: The results obtained in this study suggest that class 3 compression stockings provide a statistically significant lower recurrence rate compared with the class 2 compression stockings.

The anesthetic action of some polyhalogenated ethers-Monte Carlo method based QSAR study.

Up to this date, there has been an ongoing debate about the mode of action of general anesthetics, which have postulated many biological sites as targets for their action. However, postoperative nausea and vomiting are common problems in which inhalational agents may have a role in their development. When a mode of action is unknown, QSAR modelling is essential in drug development. To investigate the aspects of their anesthetic, QSAR models based on the Monte Carlo method were developed for a set of polyhalogenated ethers. Until now, their anesthetic action has not been completely defined, although some hypotheses have been suggested. Therefore, a QSAR model should be developed on molecular fragments that contribute to anesthetic action. QSAR models were built on the basis of optimal molecular descriptors based on the SMILES notation and local graph invariants, whereas the Monte Carlo optimization method with three random splits into the training and test set was applied for model development. Different methods, including novel Index of ideality correlation, were applied for the determination of the robustness of the model and its predictive potential. The Monte Carlo optimization process was capable of being an efficient in silico tool for building up a robust model of good statistical quality. Molecular fragments which have both positive and negative influence on anesthetic action were determined. The presented study can be useful in the search for novel anesthetics.