Polonca Ferk

CAG repeat polymorphism in androgen receptor gene is not directly associated with polycystic ovary syndrome but influences serum testosterone levels.

Hyperandrogenemia has been the most consistent feature of polycystic ovary syndrome (PCOS). Androgens exert their effects through androgen receptors (ARs). The expansion of the codon CAG trinucleotide repeat polymorphism in exon 1 of the AR gene represents a type of genetic alteration associated with changes in the AR gene function. The purpose of this study was to establish a possible association of the AR gene CAG repeat length polymorphism with PCOS, and its influence on clinical and biochemical androgen traits. Two hundred and fourteen Croatian women with PCOS and 209 healthy control women of reproductive age were enrolled. Phenotypic hyperandrogenism, BMI and waist to hip ratio were recorded. Hormonal profiles, fasting insulin and glucose levels were measured on cycle days 3-5. Genotyping of the CAG repeat polymorphism in the AR gene was performed. We found no significant difference in the mean CAG repeat number between the PCOS patients and controls (22.1±3.4 vs. 21.9±3.2, P=0.286). There was a positive correlation between the CAG repeat length and total testosterone (TT) in the PCOS group (R=0.225, P=0.015). A multiple linear regression model using mean CAG repeat length, BMI, age and HOMA-IR as predictors explained 8.5% (adjusted R²) of the variability in serum TT levels. In this model the CAG repeat polymorphism was found to be a significant predictor of serum TT levels in PCOS patients (P=0.015). The logistic regression analysis revealed that the CAG repeat length is not a significant predictor of hirsutism and acne status (P=0.921 and P=0.437, respectively). The model was adjusted for serum TT, free testosterone, androstendione and DHEAS levels as independent variables, which were also not found to be significant predictors of hirsutism (P=0.687, P=0.194, P=0.675 and P=0.938, respectively) or acne status (P=0.594, P=0.095, P=0.290 and P=0.151, respectively). In conclusion, the AR CAG repeat polymorphism is not a major determinant of PCOS in the Croatian population, but it is a predictor of serum TT level variability in women with PCOS.

Hormone replacement therapy and some risk factors for breast cancer among Slovenian postmenopausal women

Objective The aim of the study was to examine the influence of the use of hormone replacement therapy (HRT) and of some generally recognized risk factors on breast cancer risk among Slovenian postmenopausal women. Methods Eligible women diagnosed with breast cancer and a control group of women of the same age and ethnicity were invited to participate in the case–control study via a personal letter and asked to complete a written questionnaire. Adjusted odds ratios and 95% confidence intervals were estimated using multivariate logistic regression analysis. Results A total of 784 cases and 709 controls aged 50–69 years were enrolled. HRT use was inversely associated with breast cancer risk. The effect was most pronounced with the use of estrogen-only replacement therapy (odds ratio (OR) 0.51, 95% confidence interval (CI) 0.30–0.87). Longer duration of HRT use did not result in a significant change in risk (1 to <5 years of HRT use: OR 0.44, 95% CI 0.26–0.73; ≥5 years of HRT use: OR 0.51, 95% CI 0.30–0.87). Obesity (25 ≤body mass index <30 kg/m2: OR 1.34, 95% CI 1.04–1.73; body mass index ≥30 kg/m2: OR 1.89, 95% CI 1.36–2.63), smoking ≥10 cigarettes per day (OR 1.70, 95% CI 1.20–2.43), and any first-degree relative with breast or ovarian cancer (OR 1.52, 95% CI 1.11–2.08) were positively associated with breast cancer risk. Conclusions Our analysis revealed some differences from the previously published literature, which might reflect underlying demographic changes. Comprehensive medical care in HRT users without pre-existing breast abnormalities probably reduces the incidence of new breast cancer cases in Slovenia.

A research information system (RIS) for breast cancer genetics

In healthcare great quantities of patient’s data are collected for healthcare and administrative/financial purposes. Some of these data would be very useful for potential research, however, for any serious research, uniform and standardised data are needed which are normally scattered among many different electronic and also paper based information data sources. We had a similar problem in our breast cancer genetics study, so a decision was made to develop a simple and lightweight web based research information system (RIS) which would allow user friendly data input, search, edit and export with low maintenance costs. For development our in-house system for automatic application generation (AAGIP) was used. Developed research information system is secure (all data between server and clients are encrypted by using 256-bit SSL protocol and database on server is periodically backuped), highly compatible (it was tested with number of popular browsers like Mozilla/Firefox, IE, Opera, Chrome, Safari...), fast (doesn’t use any high demanding graphical gadgets), userfriendly and allows (international) users simple data input (in local languages by using Unicode UTF-8 standard) and data usage/export for different simple or advanced analyses.

Risk factors for HR- and HER2-defined breast cancer in Slovenian postmenopausal women.

Objective The study aimed to investigate the influence of some generally recognized risk factors for hormone receptor (HR)- and human epidermal growth factor receptor 2 (HER2)-defined breast cancer among Slovenian postmenopausal women. Method Eligible women diagnosed with breast cancer were compared with 709 controls of the same age and ethnicity. Immunohistochemistry and FISH analyses were used to classify cases into molecular subtypes: 454 HR+, 106 HR−, 81 HER2+ and 603 HER2−. Adjusted odds ratios and 95% confidence intervals were estimated using multivariate logistic regression analysis. Results Overweight and obese women were at increased risk of HR+, HER2− and of HR+, HR−, HER2− tumors, respectively. Women who started menstruating at the age of 11 years or earlier were at decreased risk of ER−PR− tumors. Users of hormone replacement therapy (HRT) were negatively associated with HR+ and HER2− tumors. The inverse effect was most pronounced with the use of estrogen-only HRT, and longer duration of HRT use did not result in a significant change in risk. In contrast, combined HRT decreased the risk of HER2+ tumors. Having a first-degree relative with breast and/or ovarian cancer increased the risk of HR+ and HER2− tumors. Conclusion We conclude that certain breast cancer risk factors may vary by molecular subtypes. According to our results, HRT use may have a greater influence on HR + and HER2− breast cancers and the risk of HER2-defined breast cancer may differ with respect to the regimen of HRT.

Expression of organic cation transporter 3 (SLC22A3) and plasma membrane monoamine transporter (SLC29A4) in human umbilical vein endothelial cells and their relevance for histamine uptake

Background Increased plasma histamine levels lead to pathological events. Endothelial cells actively participate in histamine clearance by promoting its uptake via yet unidentified carriers, thus limiting histamine effects. The organic cation transporter 3 (OCT3) and plasma membrane monoamine transporter (PMAT) are the two most prominent transporters for endogenous monoamines. OCT3 and PMAT show Na/K-ATPase independency. Both are highly sensitive to inhibition by the isocyanine compound, decynium-22. However, OCT3 is highly sensitive to corticosteron, whereas PMAT is not. We showed in the past that decynium-22 inhibits histamine uptake in cultured human umbilical vascular endothelial cells (HUVEC). In the present study we identified the expression of OCT3 and PMAT in freshly isolated and cultured HUVEC as well as some characteristics of histamine uptake in cultured HUVEC such as ouabain and corticosteron sensitivity.

Consumption of antihypertensives in Slovenia and comparison with Norway

Background: Prescribing antihypertensives is increasing in Slovenia and worldwide. This article is aimed to analyze changes in prescribing antihypertensives in Slovenia in the years 2002–2008, as well as to find out to what extent the prescribing followed the Slovenian guidelines. Furthermore, the consumption of antihypertensives in Slovenia was compared with the consumption in the same period in Norway. Methods: We acquired statistical data on the number of primary care prescriptions of antihypertensives and defined daily doses (DDD) per 1000 inhabitants per day from the publications Primary Care Prescribing of Drugs in Slovenia, based on Anatomical-Therapeutic-Chemical Classification (ATC), published by the National Institute of Public Health for each year from 2002 to 2008. We calculated the number of prescriptions of each active ingredient, registered in Slovenia, of antihypertensive subgroups C02, C03, C07, C08 and C09 as well as for whole subgroups. Data on the consumption of antihypertensives in Norway were acquired from the website of the Norwegian Institute of Public Health. Results: In Slovenia, the number of prescriptions for antihypertensives per 1000 inhabitants increased by 57 % during the period 2002–2008. The increase in prescribing antihypertensives was highest between 2002 and 2003. Each year, the most widely prescribed drugs in Slovenia were agents acting on the renin-angiotensin system and the most widely prescribed active ingredient from this subgroup was enalapril. During the studied period, the relative consumption of beta blocking agents increased the most. In Slovenia, relatively more antihypertensives from the C02 subgroup and agents acting on the renin-angiotensin system (C09), but less diuretics (C03), beta blocking agents (C07) and calcium channel blockers (C08) were used, compared to Norway. Conclusions: Consumption of antihypertensives in Slovenia increased by more than a half in the period 2002–2008. The association between the increasing number of prescriptions for antihypertensives and the quality of arterial hypertension control in Slovenia has not been evaluated yet. Compared to Norway, Slovenia is more oriented to prescribing agents acting on the renin-angiotensin system.

Predicting potential drug-drug interactions on topological and semantic similarity features using statistical learning

Drug-drug interaction (DDI) is a change in the effect of a drug when patient takes another drug. Characterizing DDIs is extremely important to avoid potential adverse drug reactions. We represent DDIs as a complex network in which nodes refer to drugs and links refer to their potential interactions. Recently, the problem of link prediction has attracted much consideration in scientific community. We represent the process of link prediction as a binary classification task on networks of potential DDIs. We use link prediction techniques for predicting unknown interactions between drugs in five arbitrary chosen large-scale DDI databases, namely DrugBank, KEGG, NDF-RT, SemMedDB, and Twosides. We estimated the performance of link prediction using a series of experiments on DDI networks. We performed link prediction using unsupervised and supervised approach including classification tree, k-nearest neighbors, support vector machine, random forest, and gradient boosting machine classifiers based on topological and semantic similarity features. Supervised approach clearly outperforms unsupervised approach. The Twosides network gained the best prediction performance regarding the area under the precision-recall curve (0.93 for both random forests and gradient boosting machine). The applied methodology can be used as a tool to help researchers to identify potential DDIs. The supervised link prediction approach proved to be promising for potential DDIs prediction and may facilitate the identification of potential DDIs in clinical research.

Safety issues of compounds acting on adenosinergic signalling

Much research has been performed on the field of identifying the roles of adenosine and adenosinergic signalling, but a relatively low number of marketing authorizations have been granted for adenosine receptor (AdR) ligands. In part, this could be related to their safety issues; therefore, our aim was to examine the toxicological and adverse effects data of different compounds acting on adenosinergic signalling, including different AdR ligands and compounds resembling the structure of adenosine. We also wanted to present recent pharmaceutical developments of experimental compounds that showed promising results in clinical trial setting.