Krasimira Prodanova

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• Professor, PhD
• Professor at Technical University of Sofia

Bisphosphonates are a group of drugs that are widely used in the treatment of osteoclast-mediated diseases related to bone loss. Since 2003 the problem of bisphosphonate-associated osteonecrosis of the jaws (BAONJ) has been raised, and many authors have published the cases they have observed. BAONJ is a multifactorial disease, and the risk factors...

Background This retrospective clinical study aims to compare the functional and radiological outcomes after open reduction and internal fixation versus minimally invasive plate osteosynthesis of unstable proximal humerus fractures treated with both locking plate and intramedullary graft. Methods Forty-seven patients with proximal humerus fractures...

The most important clinical indicators of temporomandibular disorders (TMD) are pain in the temporomandibular joints, masticatory and cervical muscles, as well as a reduction in the opening capacity of the mouth. Psychosocial factors have a significant impact in the persistence of the disease and should be taken in consideration in the treatment pl...

Background The aim of this study was to compare the functional and radiological outcomes between open reduction and internal fixation (ORIF) and minimally invasive plate osteosynthesis (MIPO) with locking plate (LP) and intramedullary graft (IMG) for treatment of unstable proximal humerus fractures (PHFs). Methods Forty-seven patients with PHFs we...

Data on NT-proBNP serum levels and echocardiographic indices in patients with dual-chamber pacemaker are scarce. The purpose of this study is to explore the changes, if any in certain echocardiographic indices including LV volumes, LAV index, LVEF and levels NT-proBNP, and their relationships in patients with dual chamber pacing over the 24 weeks a...

International Journal of Applied Mathematics ————————————————————– Volume 35 No. 4 2022, 601-609 ISSN: 1311-1728 (printed version); ISSN: 1314-8060 (on-line version) doi: http://dx.doi.org/10.12732/ijam.v35i4.8 COMPARISON OF BINARY REGRESSION MODELS FOR THE OUTCOME OF PEDIATRIC LIVER TRANSPLANTATION Y. Uzunova1 §, K. Prodanova2 1University Hospital...

The project "Stochastics and Simulations Models in the Medicine, Social Sciences and Dynamical Systems" is focused on the stochastics models and their application in the field of medicine, insurance, astrophysics and some simulation models applicable in social sciences and thermohydraulic processes. There are six work packages included in the resea...

Fever of unknown origin (FUO) is a clinical condition extremely difficult to diagnose. For this purpose a number of methods are used – clinical and paraclinical, as well as medical imaging, of which only nuclear-medical diagnostic methods allow performance of full-body scanning, which avoids skipping areas, loss of time and resources. In this artic...

Liver transplantation is treatment of choice for patients with end stage liver disease (ESLD). However, due to high surgical risk and risk of complications from the immunosuppressive agents pose significant challenges in transplanting setting. The aim of our study was to evaluate survival after liver transplantation. In this paper survival analysis...

In recent years, survival rate after liver transplantation in children, especially in the early postoperative period, is very high. At the same time there are many complications that can lead to death in this period. Therefore, it is important to look for parameters that can predict a lethal outcome. The duration of mechanical ventilation after liv...

The purpose of this article is to introdused the inference techniques for the mean vector μ, the correlation matrix π and the covariance matrix Σ of the multivariate normal sample and to apply these techniques using the software package STATISTICA 13.0 (StatSoft Inc, USA). The sample contains 50 weekly return observations (in percent) on each of te...

Our previous studies showed activation of coagulation in the early hours of the clinical manifestation of paroxysmal atrial fibrillation (PAF). Plasma coagulation activity of factor II, factor V, factor VII, factor VIII, factor IX, factor X, factor XI, factor XII, vWF, tissue factor levels, FVIII, vWF, prothrombin fragment 1+2(F1 + 2) and fibrinope...

Introduction: Paroxysmal atrial fibrillation (PAF) is a well-documented prothrombotic state that carries significant embolic risk. However, precise hemostatic changes in the very early stage of the disease are not completely studied. The aim of the study was to study von Willebrand factor (vWF) and coagulation factor VIII (FVIII) plasma levels and...

Background: Paroxysmal atrial fibrillation (PAF) is associated with an increased incidence of embolic events, even in patients with no embologenic risk factors. This fact raises the question for the hypercoagulability in PAF as a state closely related to the arrhythmia itself, independent of other well established embologenic risk factors. The sca...

Diagnostic tests are a cornerstone in modern medicine. They are used not only to confirm the presence of a disease but also to rule out the disease in healthy subjects. Tests with two outcome categories (i.e. presence/absence) are known as dichotomous tests. Their inherent validity is determined by sensitivity and specificity and the receiver opera...

Background: Atrial fibrillation (AF) is a hypercoagulable state. However, the intimate mechanisms leading to impaired coagulation and the timing of their activation are unclear. The aim of the study was to investigate the factors that initiate the coagulation cascade in the early hours (up to 48 h) of clinical manifestation of paroxysmal atrial fi...

Neuroblastoma is the most common solid tumor in children under 5 years of age. In this paper analysis of variance (ANOVA) is used to determine the prognostic significance of Imaging Defined Risk Factors (IDRF) for the time of relapse or death. IDRFs include a list of 20 conditions, separated across bodily compartments of tumor origin, with a slight...

Liver transplantation (LT) is a curative treatment for end-stage liver disease in the childhood. Pediatric LT is one of the most up-to-date and fast-growing areas in contemporary medicine. The main goal in this area is to create predictive models for an onset of complications that would increase survival rate. Infectious complications are the leadi...

Molecular docking algorithms predict the binding of a macromolecule (receptor) and a small molecule (ligand). Virtual screening by molecular docking has become established as a method for drug lead discovery and optimization. All docking algorithms make use of a scoring function in combination with a method of search. Presuming adequate search stra...

Colorectal carcinoma (CRC) is the third most common malignant tumor among all organ localizations and second most common cause of mortality in developed countries. CRC is divided into three main histological types according to the WHO classification: carcinomas, neuroendocrine neoplasms and mesenchymal tumors. The most common type is the adenocarci...

Neuroblastoma is the most commonsolid tumor in children under 5 years of age. In this paper survival analysis is used to determine the prognostic significance of Imaging Defined Risk Factors (IDRF) and to model the time it takes for relapse or death. The data is obtained from 42 patients – 16 boys and 26 girls, who have been admitted to the Univers...

The predictive value of serum sodium concentration on the early outcome after pediatric liver transplantation Yordanka Uzunova Sofia University St. Kliment Ohridski, Bulgaria The aim of the present study is to evaluate the relationship between the serum sodium concentration and the probability of the outcome in early postoperative period after pe...

Modeling survival in Childhood Acute Lymphoblast Leukemia Nadejda Yurukova - Ph.D., Specialized Children’s Oncohematology Hospital, Sofia, Bulgaria Krasimira Prodanova - Ph.D., Technical University of Sofia, Faculty of Applied Mathematics&Informatics, Sofia, Bulgaria Presentes: Krasimira Prodanova - Ph.D., Technical University of Sofia, Faculty of...

The aim of this study is to compare the pain intensity reduction between the mean radiation doses per session of gallium-aluminum-arsenide (GaAIAs) laser with superluminous diodes (SLD) in four of the most common pain-related chronic temporomandibular disorders (TMD) - local myalgia, myofascial pain, myofascial pain with a referral, and arthralgia....

Using a two-factor logistic regression analysis an estimate is derived for the probability of absence of infections in the early postoperative period after pediatric liver transplantation. The influence of both the bilirubin level and the international normalized ratio of prothrombin time of blood coagulation at the 5th postoperative day is studied...

Orthotopic liver transplantation (OLT) is the only curative treatment for end-stage liver disease. Early diagnosis and treatment of infections after OLT are usually associated with improved outcomes. This study’s objective is to identify reliable factors that can predict postoperative infectious morbidity. 27 children were included in the analysis....

Abstract: Introduction: The World Health Organization (WHO) 2003 report stated nearly 60%-90% of school children and most adults in industrialized nations had dental caries. Purpose: To conduct an study of dental caries intensity of temporary teeth of children from the town Varna aged 4 to 6 years. Materials and Methods: The study included 300 chil...

Introduction Pneumatization of the maxillary sinus can be triggered throughout a patient's life. Prior to any sinus floor augmentation procedure it is imperative to conduct a linear and volumetric assessment of the maxillary sinus. Materials and methods The CBCT scans in this randomized retrospective study were selected from 120 patients (50 men an...

Background Data on coagulation changes in paroxysmal atrial fibrillation (PAF) are scarce. The aim of this study was to examine plasma antithrombin (AT) levels and activity as well as thrombin-antithrombin (TAT) complex levels in the early hours of the clinical manifestation of PAF. Methods Fifty-one patients (26 men and 25 women; mean age 59.84 ±...

Introduction: The surgeon`s detailed anatomical knowledge of the operated region proves crucial for the surgery outcome. Maxillary sinus floor augmentation using lateral window demands awareness of the thickness of the sinus vestibular wall as well as the presence of bony canal containing the blood supplying alveolar antral artery. Material and me...

The objective of the present study was to evaluate the anatomical features and location of maxillary bony septa using CBCT and to provide preoperative recommendations for the oral/maxillofacial surgeons to prevent complications during surgical interventions. Materials and methods The study reviewed 153 sinuses in 139 patients undergoing sinus lift...

Background A number of data have been accumulated on inflammation in persistent and permanent atrial fibrillation (AF). Our aim was to study the process in paroxysmal AF (PAF) by measuring plasma concentrations of high-sensitivity C-reactive protein (hs-CRP), serum amyloid A (SAA) and fibrinogen in dynamics. Methods The markers were investigated i...

The objective of this study was to test the clinical effectiveness of the combined gallium-aluminum-arsenide laser (GaAlAs; 785 nm) and superluminiscent diods (SLD; 633 nm) phototherapy (MedX 1100 device) for the treatment of 62 patients with 7 of the most common pain-related temporomandibular disorders with highest sensitivity and specificity acco...

Background: In our previous studies on the oxidative status of patients with paroxysmal atrial fibrillation (PAF) we found eight oxidative biomarkers-plasma malondialdehyde (Pl-MDA), erythrocyte malondialdehyde (Er-MDA), plasma glutathione (Pl-GSH), erythrocyte glutathione (Er-GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase...

The aim of this study is to define the prognostic factors for implant survival of immediately loaded tilted implants in the edentulous maxillae placed into Bio-Oss grafted sinuses. A total of 44 tilted Bredent implants in 24 grafted sinuses were inserted 9 to 10 months after the augmentation procedures. Loading was applied within 12 hours of implan...

Background: Recent research has demonstrated disturbances of copper balance in the development of cardiovascular diseases. Copper status in patients with atrial fibrillation is still unknown. Serum or plasma copper and ceruloplasmin activity are widely used laboratory indicators of copper status.

Acute lymphoblastic leukemia (ALL) is the most common malignancy diagnosed in children, representing nearly one third of all pediatric cancers. About 30 % of the children with ALL have a gene marker. The most frequent abnormality is t (12; 21) resulting in TEL-AML1 gene rearrangement. This molecular marker can be detected in 20 % to 30 % of the cas...

The presence of a periampullary duodenal diverticulum (PDD) is often observed during upper digestive tract barium meal studies and endoscopic retrograde cholangiopancreatography (ERCP). A few papers reported that the diverticulum had something to do with the incidence of pancreatitis. The aim of this study is to investigate if the presence of duode...

In the present paper the statistical properties of the estimated parameters for drug protein binding are discussed. An approximation of the covariance matrix and confidence intervals for these parameters are obtained.

In previous author's papers some problems of individualization and also some optimization problems related with the individual therapy of a patient were considered. A two compartment pharmacokinetic model was used to solve the following problem: First, a problem of identification was formulated and solved – this means to determine on the basis of e...

The paper discusses the optimization of the continuance of the Damp‐Heating Process of a steaming iron press machine, and the preserving of the lustre of the fabrics. In order to be obtained high qualitative damp‐heating processing, it is necessary to monitor parameters such as temperature, damp, and pressure during the process. The purpose of the...

The least square estimator (LSE) of the coefficients in the classical linear regression models is unbiased. In the case of multicollinearity of the vectors of design matrix, LSE has very big variance, i.e., the estimator is unstable. A more stable estimator (but biased) can be constructed using ridge‐estimator (RE). In this paper the basic methods...

Electricity demand is one of the most important variables required for estimating the amount of additional capacity required to ensure a sufficient supply of energy. Demand and technological losses forecasts can be used to control the generation and distribution of electricity more efficiently. The aim of this paper is to utilize time series model,...

The protein binding of piroxicam, a widely used non-steroidal anti-inflammatory drug has been investigated by high-performance liquid affinity chromatography, with phenylbutazone and diazepam used as markers for binding-site characterization, and by circular dichroism titration. It was found that piroxicam binds to high-affinity phenylbutazone-bind...

A new approach for analysis of circular dichroism titration data for the investigation of drug-protein binding is proposed. The molar ellipticity change and the total drug concentration are considered as a function of the concentration of unbound (free) drug. A new minimization algorithm for estimating the number of classes of binding sites and the...

Some pharmacokinetic and pharmacodynamic interactions between digoxin and gentamicin were studied in experiments on rabbits, guinea-pigs and cats. An increase of digoxin serum levels and changes in some basic pharmacokinetic parameters of digoxin (t1/2 alpha, t1/2 beta, AUC, AL) were established in gentamicin-pretreated rabbits, the changes being d...

Vephylline (7,2-bis-2-hydroxyethylamino-1, 3-dimethylxanthine tartarate) is a xanthine derivative with high bronchodilating activity, low toxicity, and weak effects on the central nervous system. The aim of this study is to determine the pharmacokinetic parameters of vephylline after intravenous and oral (in solution and in tablets) administration...

Tetraminol (trans-2-hydroxyethylamino-3-hydroxy-5,8-dimethoxy-1,2,3, 4-tetrahydronaphthalene hydrochloride) is a newly synthesized antihypotensive agent. Its pressor activity is accompanied by a compensatory slowing down of heart rate. Changes in plasma levels after intravenous administration of 1 and 2 mg/kg b.w. to rats and rabbits can be fitted...

In the paper one ill posed problem from pharmacokinetics is studied. The human body is assumed to be a control system. The transit times of drug molecules are considered as independent random variables with the same distribution function. The corresponding density function is considered as a transport function of the system. First the parameters of...