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Herb-drug interactions are an important safety concern and this study was conducted regarding the interaction between the natural top-selling antidepressant remedy Hypericum perforatum (Hypericaceae) and conventional drugs. This study examined the influence of acute pretreatment with different extracts of Hypericum perforatum from Serbia on pentobarbital-induced sleeping time, impairment of motor coordination caused by diazepam and paracetamol pharmacokinetics in mice. Ethanolic extract, aqueous extract, infusion, tablet and capsule of Hypericum perforatum were used in this experiment. The profile of Hypericum perforatum extracts as well as paracetamol plasma concentration was determined using RP-HPLC analysis. By quantitative HPLC analysis of active principles, it has been proven that Hypericum perforatum ethanolic extract has the largest content of naphtodianthrones: hypericin (57.77 µg/mL) and pseudohypericin (155.38 µg/mL). Pretreatment with ethanolic extract of Hypericum perforatum potentiated the hypnotic effect of pentobarbital and impairment of motor coordination caused by diazepam to the greatest extent and also increased paracetamol plasma concentration in comparison to the control group. These results were in correlation with naphtodianthrone concentrations. The obtained results have shown a considerable influence of Hypericum perforatum on pentobarbital and diazepam pharmacodynamics and paracetamol pharmacokinetics.

SUMMARY Together with genetic alterations, aberrant epigenetic regulation of gene expression also plays a major role in the development of many diseases, including cancer. Overall, when compared to normal cells, the genome of malignant cells is characterized by global DNA hypomethylation and histone hypoacetylation. Considering the significance of DNA methylation and histone acetylation in the initiation and progression of human cancer, epigenetic modifications are identified as novel therapeutic targets. In contrast to genetic alterations, epigenetic changes in cancer are potentially reversible. This fact resulted in the development of pharmacologic inhibitors of DNA methyltransferases (DNMTs) and histone deacetylases (HDACs). These compounds can reverse epigenetic silencing of tumor suppressor genes by inducing the demethylation of DNA and histone acetylation, resulting in reactivation of these genes in tumor cells and restoration of crucial cellular pathways. However, it is still unclear whether the majority of HDAC inhibitors’ effects are the result of alterations of histone acetylation patterns or changes in growth regulatory pathways deregulated by the increased acetylation of non-histone proteins. Although DNMT and HDAC inhibitors can be active as monotherapy, it is widely accepted that the most effective clinical application of epigenetic modulators may be in combination with other agents. Much remains to be elucidated about the epigenome, regarding its role and its dysregulation in cancer, and therefore future research is needed to provide sufficient information for optimization of epigenetic therapy in clinical practice.

Background/Aim. It is known that bile acids improve the absorption, bioavailability and pharmacodynamic characteristics of some drugs. Morphine analgesia is produced by activation of opioid receptors within the central nervous system (CNS) at both spinal and supraspinal levels. Since a morphine molecule contains 3 polar groups and therefore hard to transfer through the blood-brain barrier, the aim of the study was to examine the potential influence of bile acids derivates, namely sodium salt of monoketocholic acid (MKH-Na) and methyl ester of monoketocholic acid (MKH-Me), on analgesic effect of morphine. Methods. White male mice of NMRI-Haan strain, with body weight of 20-24 g, were used in this study. The analgesic effect of morphine (administered by subcutaneous and intramuscular route in a dose of 2 mg/kg), with and without pretreatment with MKH-Na (4 mg/kg) and MKH-Me (4 mg/kg) was estimated by the hot plate method. Results. Administration of MKH-Me prior to subcutaneous administration of morphine increased the morphine analgesic effect but the increase was not statistically significant. At the same time administration of MKH-Na did not affect morphine analgesic effect. The analgesic effect of morphine increased when administered intramuscularly 20 min after MKH-Me administration. When compared with the group of animals treated only with morphine, a statistically significant increase in analgesic effect was detected 10, 30, 40 and 50 min after morphine administration (p < 0.05). Pretreatment with MKH-Na did not affect morphine analgesic effect. Conclusion. According to the results of this study it can be presumed that after intramuscular morphine administration methyl ester of monoketocholic acid increases morphine transport into the central nervous system and consequently the analgesic effect, as well. Further research on bile acids-morphine interaction both in vitro and in vivo is necessary to completely elucidate the mechanism of this interaction and increase in the morphine analgesic effect. [Projekat Ministarstva nauke Republike Srbije, br. 41012: Interactions of xenobiotics and the impact on biomedical system i br. 172050: Development and application of advanced chromatographic and spectroscopic techniques in analysing xenobiotics and the mechanisms of their decomposition in biotic and abiotic samples]

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Bile acids are endogenous emulsifiers synthesized from cholesterol having a peculiar amphiphilic structure. Appreciation of their beneficial effects on human health, recognized since ancient times, has expanded enormously since the discovery of their role as signaling molecules. Activation of farnesoid X receptor (FXR) and Takeda G-protein receptor-5 (TGR5) signaling pathways by bile acids, regulating glucose, lipid and energy metabolism, have become attractive avenue for metabolic syndrome treatment. Therefore, extensive effort has been directed into the research and synthesis of bile acid derivatives with improved pharmacokinetic properties and high potency and selectivity for these receptors. Minor modifications in the structure of bile acids and their derivatives may result in fine-tuning modulation of their biological functions, and most importantly, in an evasion of undesired effect. A great number of semisynthetic bile acid analogues have been designed and put in preclinical and clinical settings. Obeticholic acid (INT-747) has achieved the biggest clinical success so far being in use for the treatment of primary biliary cholangitis. This review summarizes and critically evaluates the key chemical modifications of bile acids resulting in development of novel semisynthetic derivatives as well as the current status of their preclinical and clinical evaluation in the treatment of metabolic syndrome, an aspect that is so far lacking in the scientific literature. Taking into account the balance between therapeutic benefits and potential adverse effects associated with specific structure and mechanism of action, recommendations for future studies are proposed.

Type 2 diabetes (T2D) is characterised by β-cell damage and hyperglycaemia. The lipophilic drug, probucol, has shown significant β-cell protective and potential antidiabetic effects, which were enhanced by hydrophilic bile acid incorporation using taurocholic acid and chenodeoxycholic acid. However, probucol has severe cardiotoxicity and a variable absorption profile, which limit its potential applications in T2D. Accordingly, this study aimed to design multiple formulations to optimise probucol oral delivery in T2D and test their effects on probucol absorption and accumulation in the heart. Adult male mice were given a high fat diet (HFD), and a week later, injected with a single dose of alloxan to accelerate T2D development, and once diabetes confirmed, divided into three groups (six to seven mice each). The groups were gavaged a daily dose of probucol powder, probucol microcapsules, or probucol-bile acid microcapsules for three months, and euthanized; and blood, tissues, and feces collected for blood glucose and probucol concentration analyses. Probucol concentrations in plasma were similar among all the groups. Groups given probucol microcapsules and probucol-bile acid microcapsules showed significant reduction in probucol accumulation in the heart compared with the group given probucol powder (p

Tacrolimus is an immunosuppressant used for the prevention of kidney allograft rejection. The effects of comedication on tacrolimus trough concentrations (TTC) in kidney transplant recipients, subjected to basic immunosuppressant regime consisting of tacrolimus, corticosteroids and mycophenolate mofetil were investigated. This retrospective case series study involved 208 of these patients, with the outpatient examination recorded in the database of patients, at the unit of monitoring, with a total of 5,011 such examinations. Binary logistic regression analysis has shown that calcium channel blockers, diuretics and proton pump inhibitors (PPIs) significantly affected TTC (p < 0.001). PPIs significantly increased the number of examinations in which the TTC were in the recommended therapeutic range (from 5 to 15 ng/ml), as well as over the therapeutic range (p < 0.0001). When calcium channel blockers were added to PPIs, even more pronounced effect was obtained in comparison to triple-drug therapy only (p < 0.0001). In case a diuretic was given with a PPI, a significantly increased number of examinations with subtherapeutic TTC was observed when compared with PPI only (p = 0.0203). The combination of calcium channel blockers, diuretics and PPIs resulted in the number of examinations with TTC in the recommended therapeutic range not being different from the number of examinations with TTC in the triple-drug therapy only (p = 0.3829). β-adrenergic antagonists can be administered without fear of affecting the tacrolimus optimal therapeutic concentrations. This was confirmed with all combinations of the examined drugs used in patients subjected to kidney transplantation concomitantly with β blockers.

Bile acids are naturally produced in humans and are known to provide human health benefits through their endocrinological, microfloral, metabolic and other affects that are still to be elucidated. In recent years, there has been a growing interest in using bile acids as absorption enhancers for drug delivery. Bile acids are amphiphilic molecules with a unique ability to facilitate and promote drug permeation through biological membranes. The role of bile acids in promoting drug permeation has been experimentally illustrated in various pharmaceutical formulations including oral, nasal, ocular, buccal, pulmonary and rectal delivery as well as through the blood–brain barrier. Recently, bile acids have drawn attention in the field of drug delivery due to their ability to act as a drug carrier system in the form of mixed micelles, bilosomes and chemical conjugates with drug molecules. Bile acids have demonstrated a unique ability to enhance the epithelial transport of hydrophilic drugs through the paracellular...

TGR5 is the G-protein-coupled bile acid-activated receptor, found in many human and animal tissues. Considering different endocrine and paracrine functions of bile acids, the current review focuses on the role of TGR5 as a novel pharmacological target in the metabolic syndrome and related disorders, such as diabetes, obesity, atherosclerosis, liver diseases and cancer. TGR5 ligands improve insulin sensitivity and glucose homeostasis through the secretion of incretins. The bile acid/TGR5/cAMP signaling pathway increases energy expenditure in brown adipose tissue and skeletal muscle. Activation of TGR5 in macrophages inhibits production of proinflammatory cytokines and attenuates the development of atherosclerosis. This receptor has been detected in many cell types of the liver where it has anti-inflammatory effects, thus reducing liver steatosis and damage. TGR5 also modulates hepatic microcirculation and fluid secretion in the biliary tree. In cell culture models TGR5 has been linked to signaling pathways involved in metabolism, cell survival, proliferation and apoptosis, which suggest a possible role of TGR5 in cancer development. Despite the fact that TGR5 ligands may represent novel drugs for prevention and treatment of different aspects of the metabolic syndrome, clinical studies are awaited with the perspective that they will complete TGR5 biology and identify efficient and safe TGR5 agonists.

Various pesticides are applied in agriculture for crop protection. They could have toxic effects on nervous system, liver, kidneys and the other organs. The aim of the study was to investigate effects of occupational exposure to pesticides and consumption of alcoholic beverages on liver functions in agricultural workers. The study included sample of 117 male agricultural workers involved as tractor drivers in pesticide application at the workplace and the control group of 60 tractor drivers who do not applied pesticides. We collected data concerning age, use of alcohol and duration of exposure to pesticides. Parameters of liver functions in serum were determined in both groups of workers. In agricultural workers exposed to pesticides, activities of enzymes gamma-glutamyl transpeptidase, alanine and aspartate aminotransferases were higher comparing to the control group, but these differences were not statistically significant. Consumption of alcohol statistically significantly increased activity of gamma-glutamyl transpeptidase in both groups of workers. The most important measures concerning health protection of agricultural workers exposed to pesticides are continuous implementation of the safety measures at work, health promotion at workplace and regular health surveillance in occupational health services for the purpose of early detection of worker's health disorders.

Purpose: Animal tests have been often used in toxicology to determine parameters describing toxicity of a particular substance. However, in vivo tests must fulfill ethical requirements, and are both time and money consuming. Therefore, computational methods are considered to be very useful in toxicity prediction. Methods: Retention parameters were acquired by normal-phase TLC. Lipophilicity was used as a key parameter for predicting toxic potential. The correlation coefficients between calculated log P values obtained by five different software and experimentally determined hydrophobicity parameters ((tol/et), (tol/but), b(tol/et) and b(tol/but)) were calculated. Results: Correlation analysis provided reliable information (r2 > 0,8) for aquatic species – minnow, medaka, daphnia, and algae. In addition valuable data regarding rodents and AMES test were obtained. Conclusions: Tested bile acids show relatively good toxicological properties. Less toxic effects are noticed in compounds with higher pola...

Cefotaxime is a class III drug according to the Biopharmaceutical Classification System due to low intestinal permeability based on poor oral bioavailability. Bile salt compounds have been shown to be effective additive for drug permeation through several biological membranes. The main purpose of this study was to investigate the ability of a mixed micelles made of phosphatidylcholine, sodium deoxycholate, and loaded with a cefotaxime-3α,7α-dihydroxy-12-keto-5β-cholanate complex to enhance the oral bioavailability of cefotaxime in rats. Thin-film hydration method was used to prepare cefotaxime-loaded mixed micelles using different bile salt concentrations (0.87–25 mM of sodium deoxycholate). Overall, micelle sizes ranging from 86.9 to 155.6 nm were produced with negative zeta potential values from −15.9 to −19.5 mV and drug loading from 10.5 to 18.9 %. The oral bioavailability of cefotaxime in mixed micellar formulation was assessed and the pharmacokinetic parameters were compared with cefotaxime-3α,7α-dihydroxy-12-keto-5β-cholanate complex and cefotaxime aqueous solution. 24 Male Wistar rats were randomly allocated into four groups (n = 6, per group) to receive the following: (1) a single intravenous dose of cefotaxime (25 mg/kg) in sterilized normal saline solution for injection; (2) a single oral dose of mixed micelles (100 mg/kg of cefotaxime) in phosphate buffered saline administered by oral gavage; (3) a single oral dose of cefotaxime-3α,7α-dihydroxy-12-keto-5β-cholanate complex (100 mg/kg of cefotaxime) in phosphate buffered saline administered by oral gavage; (4) a single oral dose of free cefotaxime (100 mg/kg) in aqueous solution administered by oral gavage. Blood samples were collected for up to 24 h and cefotaxime analyzed using a validated HPLC assay. Pharmacokinetic data showed that the oral bioavailability of cefotaxime in mixed micelles was found to be 4.91 % higher compared to the cefotaxime in aqueous solution (1.30 %). Maximum concentration (C max) of cefotaxime in mixed micellar formulation was higher (1.08 ± 0.1 µg/ml) compared to the cefotaxime-3α,7α-dihydroxy-12-keto-5β-cholanate complex (0.69 ± 0.1 µg/ml) and cefotaxime in aqueous solution (0.52 ± 0.1 µg/ml). Similarly, the mean values for area under the plasma concentration–time curve extrapolated to infinity (AUC0–∞) of cefotaxime in the mixed micellar formulation was higher (3.89 ± 0.9 μg·h/mL) compared to the cefotaxime-3α,7α-dihydroxy-12-keto-5β-cholanate complex (1.52 ± 0.2 μg·h/mL) and cefotaxime in aqueous solution (1.03 ± 0.4 μg·h/mL), respectively. The mixed micellar formulation was able to increase the oral bioavailability of the BCS Class III drug cefotaxime up to fourfold by enhancing drug permeation through the mucosal membrane of the small intestine.

Aims The current treatment of Alzheimer's disease is purely symptomatic. Scientists are looking for new treatment options which could alter the course of the disease and improve the quality of life in patients with Alzheimer's disease. In this paper 14 novel s-triazine molecules have been evaluated for their lipophilicity. In addition docking study was carried out to evaluate acetylcholinesterase activity of these compounds. Main methods Lipophilicity was evaluated by RP HPTLC using 5 different mobile phases and obtained results were used in calculations of pharmacokinetic parameters - logBB, Ka and Pej. Multiple linear regression analysis was refined, taking account of molecular polarity (total polar surface area, TPSA) and molecular weight (Mw) descriptors. Appropriate QSAR models were developed. Docking studies were carried out using the Vina docking. Key findings Five out of fourteen compounds evaluated [5-10] are selected as the most promising compounds with satisfactory pharmacokinetic properties and good docking scores. Significance Compound 10 possesses the best combination of favourable pharmacokinetic characteristics (brain penetration, intestinal absorption) and capacity for acetylcholinesterase inhibition. Consequently this molecule should be further evaluated for potential therapeutic use in Alzheimer's disease.

The aim of this study was to estimate the binding-affinities of different bile acids towards drug transporters in Lactobacillus acidophilus and Bifidobacterium longum in order to predict the influence of bile acids and probiotics interactions on drug pharmacokinetics.In order to study interactions of bile acids with transporters of intestinal bacteria, molecular-docking step was performed, using SwissDock web-service. For the purpose of comparison, two natural bile acids, cholic acid (CA) and deoxycholic acid (DCA), and one semi-synthetic bile acid, 12-monoketocholic acid (MKC), were studied in parallel. The free-binding energy was used as the main criterion for ranking ligands.Studied bile acids exhibited different binding affinities towards bacterial transporters with MKC showing the most prominent effect. For the majority of studied transporters, the estimated affinities of bile acids decreased in the following order: MKC-CA-DCA. Namely, 38.7% of examined transport proteins gave the lowest free-binding energy with MKC. The weak inverse relationship between number of hydrogen bonds and estimated free-binding energies was revealed.The predominant effect of MKC for the majority of studied transport proteins suggests that keto group at carbon 12 of the steroid core has a significant influence on the properties of MKC and consequently, on interactions with membrane transporters. Present findings might have a role in the prediction of potential influence of bile acids and probiotics on drug pharmacokinetics.

Purpose Information on ADME properties of examined bile acids and their oxo derivatives are scarce, although the interest for bile acids and their use in nanochemistry and macromolecular chemistry is increasing. The purpose of this research was to evaluate the lipophilicity, a crucial physicochemical parameter for describing ADME properties of selected bile acids and their oxo derivatives, and to compare two approaches: experimentally determined hydrophobicity parameters and calculated log P values. Methods Commercially available bile acids - deoxycholic, chenodeoxycholic, hyodeoxycholic and ursodeoxycholic acid were used to synthesize oxo derivatives. Lipophilicity was evaluated in two solvent systems: toluene/ethanol and toluene/butanol. Retention parameters were acquired by normal-phase TLC. The correlations between calculated log P values obtained using five different software and experimentally determined hydrophobicity parameters ( R M 0 (tol/eth) , R M 0 (tol/but) , b (tol/eth) and b (tol/but) ) were examined. Results Correlation analysis confirmed significant dependence between experimental R M 0 values and software calculated parameters. Results suggest satisfactory intestinal absorption after oral administration for all of the examined compounds as well as low volumes of distribution, and high affinity for binding with plasma proteins. Penetration through blood-brain barrier and skin is not satisfactory. All of the examined compounds show high affinity for binding with G-protein coupled receptors and consequently inhibition of ionic channels. Results also suggest possible binding with nuclear receptors. Conclusions Established lipophilicity testing model of studied compounds showed excellent predictive ability and might represent significant tool in development of relations between chromatographic behavior and ADME properties. Compounds 3α-hydroxy-7,12-dioxo-5β-cholanoic and 12α-hydroxy-3,7-dioxo-5β-cholanoic acid might be the most suitable candidates for further development studies (satisfactory pharmacokinetic properties and lowest haemolytic potential) followed by 3α-hydroxy-12-oxo-5β-cholanoic acid and 3α-hydroxy-7-oxo-5β-cholanoic acid (slightly higher haemolytic potential, but better ligand properties).

Matricaria recutita L. (Asteraceae) is one of the most ancient medical herbs, although the therapeutic uses and health benefits of chamomile are based largely on tradition. The present study aimed to investigate the effects of chamomile extract on the intestinal motility. Due to the fact that preparation techniques could significantly alter the glucoside content in the chamomile, we also explored the possible differences in the effects on gastrointestinal motility between native and fermented chamomile extract. Thirty minutes after the administration of saline or chamomile ligulate flower extracts, all animals were orally administered charcoal meal by gavage (0.6 ml emulsion–0.4 g Carbo medicinalis and 0.2 g Gummi arabicum in 10 ml of olive oil). Animals were sacrificed by cervical dislocation 30 min after charcoal meal administration. Intestinal motility was estimated according to the distance between Carbo medicinalis and pylorus in centimeters. Both native and fermented extract decreased intestinal motility compared to control. Native chamomile extract (5 mg/kg) and fermented chamomile extract (2.5 mg/kg) significantly decreased intestinal motility compared to control group (NE5=27.41±2.79, P

Preclinical Research The development of new genomic technologies has led to an exponential increase in the number of biomarkers for drug safety and efficacy. Pharmacogenomics has the potential to impact clinically relevant outcomes in drug dosing, efficacy, toxicity, and prediction of adverse drug reactions (ADRs). Genotype-based prescribing is anticipated to improve the overall efficacy rates and minimize ADRs, making personalized medicine a reality. Genome-wide association studies have been increasingly applied to pharmacogenetics. Severe ADRs are a major issue for drug therapy because they can cause serious disorders and can be life threatening. For severe ADRs, significant associations have been reported for drug-induced liver injury, statin-induced myopathy, increased risk of hemorrhagic complications of anticoagulant use, drug-induced torsade de pointes, drug-induced long QT, and severe cutaneous ADRs. This review summarizes the current position concerning the clinical and pharmacoepidemiological relevance of pharmacogenetic biomarkers in ADR prediction and prevention, with an emphasis on genetic risk factors and biomarkers for three specific severe ADRs.

In the European Union (EU), rare diseases are defined as life-threatening or chronically debilitating diseases with prevalence lower than five in 10,000 inhabitants. Although individually rare, together, rare diseases affect a significant part of the population (27-36 million people in the EU). Therefore, patient access to orphan medicines is receiving increasing political attention in the EU. In order to assess the differences in availability of reimbursed orphan medicines among Serbia, Bulgaria and Sweden, National Reimbursement Lists were reviewed and identified orphan medicines were crossed with the List of orphan drugs in Europe, published in July 2011, available from Orphanet. The analysis of regulatory traits was based mainly on a review of the official documents setting out legislation regarding rare diseases and orphan medicines in the studied countries. Only 6.5 % (4 out of 61) of the authorised orphan medicines in Europe with prior orphan designation and 25.0 % (17 out of 68) without prior orphan designation were available and reimbursed in Serbia. In the Bulgarian Positive Drug List 44.3 % (27 out of 61) of the drugs with prior orphan designation and 50.0 % (34 out of 68) without prior orphan designation were identified. The share of reimbursed orphan medicines was the highest in Sweden among the observed countries - 52.5 % (32 out of 61) of the medicines with orphan designation and 60.3 % (41 out of 61) without prior orphan designation. According to the first level of the ATC Classification System, most of the reimbursed orphan medicines in the three studied countries belonged to the group L: "Antineoplastic and immunomodulating agents", while the most common indications for authorised and reimbursed orphan medicines were "Neoplasms" (C00-D48), with 19 available orphan drugs in Serbia, 26 in Sweden and 31 in Bulgaria. Inequities in the access to orphan medicines among Serbia, Bulgaria and Sweden may be explained by the differences in the approaches for registration, pricing and reimbursement of orphan medicines. The low share of reimbursed orphan drugs in Serbia may be due to incomplete compliance with EU legislation and existence of domestic procedure for authorisation as well. The EU legislation and policy on treatment of rare diseases obviously facilitate the penetration of orphan drugs on the EU market, but apparently there is also considerable budget impact on the availability of reimbursed orphan medicines.

The toxicity of benzene is not an issue of the past, especially in developing countries. Bone marrow toxicity is demonstrated among workers. In this study, the effect of simultaneous exposure to benzene and ethanol on benzene metabolism in mice was investigated by measuring the excretion of thioethers in urine. Urinary thioether excretion significantly decreased in the mice receiving both benzene and ethanol compared with the animals receiving benzene only. The assay of determining thioethers in urine samples in this study is a simple and low-cost method, thus suitable for routine use, especially in developing countries, not only for benzene, but also for other alkilating agents, which can be found during occupational exposure. Our results suggest that further research is needed to elucidate the mechanisms of decreased urinary excretion of thioether after simultaneous exposure to benzene and ethanol.

Background Herbal supplements are widely used in the treatment of various liver disases, but some of them may also induce liver injuries. Regarding the infuence of thyme and its constituents on the liver, conflicting results have been reported in the literature. The objective of this study was to examine the influence of two commonly used pharmaceutical formulations containing thyme (Thymus vulgaris L.), tincture and syrup, on carbon tetrachloride-induced acute liver injury in rats. Methods Chemical composition of investigated formulations of thyme was determined by gas chromatography and mass spectrometry. Activities of enzyme markers of hepatocellular damage in serum and antioxidant enzymes in the liver homogenates were measured using the kinetic spectrophotometric methods. Liver morphology was characterized by light microscopy using routine hematoxylin and eosin staining. Results Thymol was found to be predominant active constituent in both tincture and syrup. Investigated thyme preparations exerted antioxidant effects in liver by preventing carbon tetrachloride-induced increase of lipid peroxidation. Furthermore, co-treatment with thyme preparations reversed the activities of oxidative stress-related enzymes xanthine oxidase, catalase, peroxidase, glutathione peroxidase and glutathione reductase, towards normal values in the liver. Hepatotoxicity induced by carbon tetrachloride was reflected by a marked elevation of AST and ALT activities, and histopathologic alterations. Co-administration of thyme tincture resulted in unexpected exacerbation of AST and ALT values in serum, while thyme syrup managed to reduce activites of aminotransferases, in comparison to carbon tetrachloride-treated animals. Conclusions Despite demonstrated antioxidant activity, mediated through both direct free radical scavenging and activation of antioxidant defense mechanisms, thyme preparations could not ameliorate liver injury in rats. Molecular mechanisms of diverse effects of thyme preparations on chemical-induced hepatotoxicity should be more in-depth investigated.

Silymarin is a complex of five major compounds, and silibinin is the most biologically active component of the complex. The aim of this study was to investigate, evaluate and confirm the potential cardioprotective and hepatoprotective effects of administration of silymarin, rich in silibinin, at a dose of 60 mg/kg orally for a time-span of 12 days on doxorubicin induced toxicity in male Wistar rats. The in vivo model was used to explore whether silymarin could prevent damage of liver and heart tissue induced by doxorubicin administered every other day at dose of 1.66 mg/kg intraperitoneally for twelve days. In the study the change of body weight, ECG changes, biochemical parameters of oxidative stress, serum activity of alanine and aspartate transaminase, lactate dehydrogenase, creatine kinase and histological preparations of heart and liver samples of treated animals were examined. According to physiological, pharmacological, microscopic and biochemical results, we confirmed that at the examined dose, silymarin exhibits a protective influence on the heart and liver tissue against toxicity induced by doxorubicin.

Since 2005, the antiepileptic drug lamotrigine has been present in the market in various generic products, in addition to the original brand of Lamictal®. The linear pharmacokinetics and wide therapeutic window of lamotrigine enable seizure-free patients to easily switch from brand to generic antiepileptic drugs.The aim of this study was to investigate the extent of variations in lamotrigine serum concentrations between two immediate-release tablet formulations. Data were compared with in vitro difference and similarity tests on dissolution profiles of the two formulations.Dissolution characteristics of formulations A (reference) and B (test) were evaluated at three points spanning the physiologic pH range (pH 1.2, pH 4.5, pH 6.8). A model-independent approach of difference (f1) and similarity (f2) tests were applied to dissolution data. A clinical study was performed with 16 patients who were divided into two groups - one group received formulation A (n = 9) and the other received formulation B (n = 7). Lamotrigine steady-state concentrations were determined by high-performance liquid chromatography on a reverse-phase column.There were no statistically significant differences in lamotrigine serum concentrations between the two groups, although formulation B had slightly higher mean concentration values (formulation A: 3.97 ± 4.1 μg/mL; formulation B: 5.78 ± 2.7 μg/mL). Dissolution profiles of the two formulations were similar in the pH 1.2 dissolution medium; however, the dissolution profiles of formulation B were outside the dissolution limit (≥85% at 15 minutes) in the pH 4.5 and 6.8 dissolution media.No significant changes in the serum concentrations of lamotrigine were seen between the two investigated formulations. There is no evidence to suggest that the differences in dissolution profiles at pH 4.5 and pH 6.8 affect the therapeutic efficacy of the formulations. It is evident that the doses of test formulation given to the patients were higher as a consequence of common assumption that generic products have a lower absorption rate, which is proven unnecessary in this study. This investigation was a pilot study and thus further investigations with a larger sample size are necessary to determine if there is a connection between dissolution profiles and the therapeutic effect of investigated formulations.

It is known that certain bile acids have a promotive effect on the action of some drugs. Special attention is paid to bile acids having oxo groups instead of OH groups in the steroid skeleton of their molecule, since these derivatives have a lower hemolytic potential (membrane toxicity). This study examined the effects of sodium salts of 3α,12α-dihydroxy-7-oxo-5β-cholanoic acid (7-oC) and 3,7,12-trioxo-5β- cholanoic acid (3,7,12-toC) on the adsorption of verapamil hydrochloride on activated carbon (model of the cell membrane). The interaction was followed by measuring the effect of verapamil on the functional dependence between the spin-lattice relaxation time T1 (protons of the C18 angular group of the bile acid molecule) and the bile acid concentration in deuterated chloroform (model of the cell membrane lipid phase). Whether a depot effect of verapamil exists when 7-oC and 3,7,12-toC (in the form of methyl esters) are present in chloroform was also investigated. It was found that 7-oC exhibited a significant effect in the experiments with verapamil, whereas 3,7,12-toC showed no difference of the measured parameters with respect to the control. This indicates that bile acid molecules should have OH groups bound to the steroid nucleus, in order to exhibit an effect on the monitored physico-chemical parameters of verapamil.

Monitoring of tacrolimus blood concentration is of utmost importance in the management of renal transplant recipients because of Narrow Therapeutic Index and highly variable pharmacokinetics. The aim of this study was to detect inter-patient pharmacokinetic variability of tacrolimus and to assess the predictability of individual tacrolimus concentrations at various times of the area under the curve (AUC) seeking to find the best sampling time to predict the exposure of tacrolimus in renal transplant recipients with triple therapy. This oral dose tacrolimus pharmacokinetics study was conducted in 18 Serbian renal transplant recipients on triple immunosuppressive therapy, including basiliximab. The first oral dose of tacrolimus (0.05 mg/kg) was given on day 5 post-transplant; blood concentration was measured by microparticle enzyme immunoassay method. Associations between each sampling time-point of concentrations and AUC12 were evaluated by Pearson correlation coefficients. Abbreviated sampling equations were derived by multiple, stepwise regression analyses. The variance in the strength of association between predicted AUC (AUCp) and AUC12 was reflected by linear regression coefficients. AUC12 showed remarkable inter-individual variations after the first oral dose of tacrolimus. The area of the maximum AUC was four times higher than that of the minimum AUC. C4 seems to be an indicator of total body exposure to tacrolimus. Alternatively, the concentrations at 1.5, 4 and 8 hr as an abbreviated AUC were as good a predictor as a full pharmacokinetic study. Our results show a significant difference between men and women. A three-point sampling method seemed to be the best abbreviated AUC for a cost-effective tacrolimus monitoring strategy.

Herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), a synthetic auxin which promotes uncontrolled plant growth is widely used. The aim of our study was to investigate, using an experimental model, the effect of herbicide 2,4-D on liver function tests, enzyme a amylase and glucose blood level. BALB/C mice were treated i.p. with the herbicide (30 mg/ kg 2,4-D) for four consecutive days. Twenty-four hours after the last injection, the treated and the control animals were weighed and sacrificed for biochemical analysis: haematocrit, glucose blood level, serum activities of enzymes alanine aminotransferase, aspartate aminotransferase, gamma glutamyl transferase, and a amylase, as well as liver reduced glutathione. Herbicide 2,4-D significantly decreased glucose blood level in mice. There were no changes in liver function tests or activity of enzyme a amylase. In this study on mice we confirmed the results obtained in the previous study, which showed a hypoglycemic effect of herbicide 2,4-D on agricultural workers. To elucidate the mechanism of this effect, a further research is needed.

Objectives Bile salts have been shown to decrease the absorption of methotrexate in the rat intestine by an unknown mechanism. We aimed to examine this effect. Methods We assessed apical-to-basolateral (AP-BL) permeation of methotrexate (5 μM) across Caco-2 cell monolayers pretreated with various concentrations (0, 0.25, 0.5, 1, 3 and 5 mm) of sodium cholate or its semisynthetic analogue, sodium 12-monoketocholate. We also determined the effect of orally administered 12-monoketocholate on the intestinal absorption of methotrexate in rats to evaluate a possible in-vitro–in-vivo correlation. Key findings It was found that sodium cholate and sodium 12-monoketocholate decreased the AP-BL permeation of methotrexate at low concentrations (maximal inhibition at 0.25 and 1 mm, respectively) and increased it at higher concentrations. Determination of [14C] mannitol permeation and electrical resistance of monolayers during experiments showed that membrane integrity was not compromised at low concentrations of bile salts but was disrupted at higher concentrations. Subsequently, we examined the effect of the simultaneous oral administration of sodium 12-monoketocholate (4, 20, 40 and 80 mg/kg) on the intestinal absorption of methotrexate in rats after an oral dose (5 mg/kg). The pharmacokinetic study showed that 12-monoketocholate at 4 and 20 mg/kg did not change the methotrexate area under the serum concentration–time curve whereas sodium 12-monoketocholate at 40 and 80 mg/kg significantly reduced it. Conclusions Sodium 12-monoketocholate appears to decrease the intestinal absorption of methotrexate in rats by inhibition of transcellular active transport.

This work is concerned with the potential promotive action of 12-monoketocholic acid (12-MKC) on the analgesic effect of morphine and tramadol. The investigation was carried out on laboratory Wistar rats divided into five test groups, each treated with either morphine (2 mg/kg), tramadol (9.6 mg/kg), 12-MKC (2 mg/kg), morphine + 12-MKC, or tramadol + 12-MKC, the control group receiving physiological solution (2 mg/kg). The effect of 12-MKC on the analgesic action of morphine and tramadol was determined by radiation heat method. Morphine and tramadol, given in equimolar doses, did not show significant difference in the degree of analgesia. In combination with morphine, 12-MKC increased significantly the analgesic effect compared with the group treated with morphine alone. However, 12-MKC caused no change in the action of tramadol. The 5-day intravenous application of 12-MKC in combination with the two analgesics caused no changes in the biochemical parameters nor pathohistological changes in the liver parenchyma of tested animals.

Bile salts are endogenous surfactants which have been widely used in drug formulation and drug delivery systems to increase drug permeation. When given by subcutaneous injection to rats, the novel bile salt, monoketocholate (MKC) has been shown to increase brain uptake of several drugs. This study aimed to characterize the physicochemical and some biological properties of MKC as a basis for understanding the mechanism by which it enhances membrane permeability. Comparison was made with three natural bile salts, cholate, deoxycholate and taurocholate. Critical micelle concentrations (CMC) were measured by the surface tension method and partition coefficients in n-octanol/buffer were measured by liquid-liquid extraction. The effects of bile salts on three different biological membrane models were investigated. Penetration studies in Langmuir monolayers indicated that MKC has only a weak ability to insert into phospholipid monolayers, but it can increase their elasticity once incorporated. In the erythrocyte model, MKC did not cause hemolysis at concentrations up to 10 mM, but changed the deformability of erythrocytes. Studies of the permeability of mannitol and transepithelial electrical resistance (TEER) across Caco-2 cell monolayers showed MKC did not cause significant increases in mannitol permeability or decreases in TEER values. In conclusion, MKC does not display strong membrane-solubilizing properties, but does change the mechanical properties of biological membranes. This effect might influence both passive and active transcellular permeation.

The knowledge of the process of formation of molecular aggregates of bile acids in aqueous media and of the corresponding critical micellar concentrations (CMCs) is of great significance because of the biological importance of these compounds and their pharmacological applications. In view of this, the present study is concerned with the determination of CMCs of cholic and chenodeoxycholic acids and their keto derivatives at different temperatures with the aim to calculate the standard thermodynamic functions of micelle formation. Based on the molecular descriptors for tested compounds and entropy of micelle formation, the method of principal component analysis (PCA) allowed grouping of the behavior of tested molecules at 30, 50 and 70 degrees C. To one group belong cholic acid and its keto derivatives, the other group consisting of chenodeoxycholic and deoxycholic acids and their keto derivatives. For each group, the derived multiple linear regression equations of the entropy dependence on temperature contains different independent variables. A main difference between the two groups of tested bile acids is in the energy of dipole-dipole interaction, which appears to be temperature dependent, and in the case of the latter group comes into play as an independent variable already in the regression equation derived for 30 degrees C. The most remarkable changes of the descriptors with temperature were observed in the group of cholic acid and its derivatives.

Aim. To investigate the influence of probiotic pre-treatment on the permeation of the antidiabetic drug gliclazide in healthy and diabetic rats. Methods. Wistar rats (age 2–3 months, weight 350 ± 50 g) were randomly allocated into one of 4 groups (N = 16 each group): healthy control, healthy probiotic, diabetic control, and diabetic probiotic. Probiotics (75 mg/kg, equal quantities of Lactobacillus acidophilus, Bifidobacterium lactis, and Lactobacillus rhamnosus) were administered twice a day for three days to the appropriate groups after diabetes had been induced with alloxan i.v. 30 mg/kg. Rats were sacrificed, ileal tissues mounted in Ussing chambers and gliclazide (200 µg/mL) was administered for the measurement of the mucosal to serosal absorption Jss(MtoS) and serosal to mucosal secretion Jss(StoM) of gliclazide. Results. Treatment of healthy rats with probiotics reduced Jss(MtoS) of gliclazide from 1.2 ± 0.3 to 0.3 ± 0.1 µg/min/cm2 (P

This study investigated the effect of a commercial preparation of stevioside and a synthetic compound, sodium salt of monketocholic acid (MKC), administered per os (p.o.) and also adminstered via an osmotic pump, on glycemia in normoglycemic and diabetic Wistar rats. Diabetes was induced with alloxan, 100 mg/kg, i.p. Normoglycemic and diabetic rats were treated p.o. for five days either with physiological solution (1 ml/kg, controls), stevioside (20 mg/kg), MKC (4 mg/kg) and a combination of stevioside (20 mg/kg) and MKC (4 mg/kg). Apart from p.o. adminstration, stevioside and MKC were also administered via a subcutaneously (s.c.) implanted osmotic pump. During treatment and upon termination of the latter, glycemia was measured and the rats that were treated p.o. were subjected to the oral glucose tolerance test (OGTTT) at a dose of 1 g/kg. Following this animals were anesthetized with urethane (0.75 g/kg, i.p.) and killed by cardiopunction to determine C-peptide levels in the serum. In all three groups of normoglycemic rats highest decrease in glucose levels was observed on the fourth day of the experiment. The stevioside + MKC combination showed a stronger hypoglycemic effect compared to individual treatments with stevioside and MKC (3.73:4.80:4.73 mmol/L). In the group of diabetic rats that received both substances via the osmotic pump, the hypoglycemic action was also stronger compared to the individual treatments with stevioside and MKC (16.15:18.89:18.75 mmol/L). The treatment of healthy rats with both substances p.o. caused no statistically significant difference in glycemia, whereas in diabetic rats the combination of stevioside + MKC showed a statistically significant decrease in glycemia compared to control values. In both groups of rats, treatment with stevioside and MKC and their combination prevented an increase in glucose concentrations in the OGTT. Only the administration of stevioside by osmotic pump yielded a statistically significant increase in the concentrations of C-peptide in the serum of healthy rats. Compared to controls, the concentrations of C-peptide in diabetic rats were significantly higher after treatment with either stevioside or its combination with MKC, irrespective of the mode of administration.

Microbiology is a rapidly changing field. As new researches and experiences broaden our knowledge, changes in the approach to diagnosis and therapy have become necessary and appropriate. Recommended dosage of drugs, method and duration of administration, as well as contraindications to use, evolve over time all drugs. Over the last 2 decades, Candida species have emerged as causes of substantial morbidity and mortality in hospitalized individuals. Isolation of Candida from blood or other sterile sites, excluding the urinary tract, defines invasive candidiasis. Candida species are currently the fourth most common cause of bloodstream infections (that is, candidemia) in U.S. hospitals and occur primarily in the intensive care unit (ICU), where candidemia is recognized in up to 1% of patients and where deep-seated Candida infections are recognized in an additional 1 to 2% of patients. Despite the introduction of newer anti-Candida agents, invasive candidiasis continues to have an attributable mortality rate of 40 to 49%; excess ICU and hospital stays of 12.7 days and 15.5 days, respectively, and increased care costs. Postmortem studies suggest that death rates related to invasive candidiasis might, in fact, be higher than those described because of undiagnosed and therefore untreated infection. The diagnosis of invasive candidiasis remains challenging for both clinicians and microbiologists. Reasons for missed diagnoses include nonspecific risk factors and clinical manifestations, low sensitivity of microbiological culture techniques, and unavailability of deep tissue cultures because of risks associated with the invasive procedures used to obtain them. Thus, a substantial proportion of invasive candidiasis in patients in the ICU is assumed to be undiagnosed and untreated. Yet even when invasive candidiasis is diagnosed, culture diagnosis delays treatment for 2 to 3 days, which contributes to mortality. Interventions that do not rely on a specific diagnosis and are implemented early in the course of Candida infection (that is, empirical therapy) or before Candida infection occurs (that is, prophylaxis) might improve patient survival and may be warranted. Selective and nonselective administration of anti-Candida prophylaxis is practiced in some ICUs. Several trials have tested this, but results were limited by low statistical power and choice of outcomes. Thus, the role of anti-Candida prophylaxis for patients in the ICU remains controversial. Initiating anti-Candida therapy for patients in the ICU who have suspected infection but have not responded to antibacterial therapy (empirical therapy) is practiced in some hospitals. This practice, however, remains a subject of considerable debate. These patients are perceived to be at higher risk from invasive candidiasis and therefore are likely to benefit from empirical therapy. Nonetheless, empirical anti-Candida therapies have not been evaluated in a randomized trial and would share shortcomings that are similar to those described for prophylactic strategies. Current treatment guidelines by the Infectious Diseases Society of America (IDSA) do not specify whether empirical anti-Candida therapy should be provided to immunocompetent patients. If such therapy is given, IDSA recommends that its use should be limited to patients with Candida colonization in multiple sites, patients with several other risk factors, and patients with no uncorrected causes of fever. Without data from clinical trials, determining an optimal anti-Candida strategy for patients in the ICU is challenging. Identifying such a strategy can help guide clinicians in choosing adequate therapy and may improve patient outcomes. In our study, we developed a decision analytic model to evaluate the cost-effectiveness of empirical anti-Candida therapy given to high-risk patients in the ICU, defined as those with altered temperature (fever or hypothermia) or unexplained hypotension despite 3 days of antibacterial therapy in the ICU.

Corallium rubrum is the most famous and precious coral due to the intense characteristic red colour of its skeleton. We have determined the presence of carotenoids in natural samples of C. rubrum from Marseille, Riou, and investigated their chemical composition. Analysis was performed both on soft tissues and hard tissues including spicules and skeleton. Since hard tissues are made of a mineral fraction and an organic fraction obtained after demineralization, extraction was performed both with and without demineralization by EDTA. The extracts were analyzed by complementary methods of TLC, HPLC/DAD and HPLC/MS. The components were separated by RP-18 chromatography column using acetonitrile/methanol for HPLC/DAD and acetonitrile/water gradient for HPLC/MS analysis. Our results give the first evidence of the presence of canthaxanthin, 4,4′-diketo-β-carotene, as the major carotenoid in all samples. Spicules exhibited higher content in carotenoids than skeleton. Demineralization treatment improved the efficiency of carotenoid extraction by an average factor of 5 and showed that organic matrix contains canthaxanthin.

Our research was aimed at establishing if and how selenium (Se) ion, N-acetylcysteine (NAC), sodium salt of monoketocholic acid (MKH) and superoxide-dismutase (SOD), administered in the experimental animal model, could affect the possible cytotoxicity as-sociated with anthracycline-based combined chemotherapy with doxorubicin, vincristine and prednisolone (DVP). The following biochemical parameters were investigated: the extent of lipid peroxidation (LPx), and the activity of peroxidase (Px), catalase (CAT), glutathione-peroxidase (GSHPx), and xanthine-oxidase (XOD). A statistical increase in LPx activity was obtained by SOD, MKH, DVPSe and DVPMKH. All chemotherapeutic agents reduced Px activity in a statistically significant manner. There was no statistical significance for the results regarding the effects of the administered substances on GSHPx activity. The results for DVP, SOD, MKH, DVPSOD, DVPSe and DVPMKH showed reduced XOD activity which was statistically significant, which was lowest in the case of MKH, while NAC and Se reduced the activity of this enzyme but statistically non significant. NAC, Se, DVP, MKH and DVPMKH caused a reduction in CAT activity, while DVPSOD and DVPSe caused an increase of the latter.

Previous studies in our laboratory have shown that the semisynthetic bile acid derivative, sodium 3α,7α-dihydroxy-12-oxo-5β-cholanate (MKC), has hypoglycemic activity. The aim of this study was to investigate the relationship between the pharmacokinetics and hypoglycemic activity of MKC in healthy and diabetic rats. Groups of healthy and alloxan-induced diabetic rats were dosed intravenously (i.v.) and orally with MKC (4 mg/kg). Blood samples were taken before administration of the dose and at 20, 40, 60, 80, 120, 150, 180, 210 and 240 minutes post-dose. MKC serum concentration was measured by HPLC, and pharmacokinetic parameters determined using the WinNonlin program. The absolute bioavailability of MKC was found to be low in healthy and diabetic rats (29 and 23% respectively) and was not significantly different between the two groups. Mean residence time (MRT), volume of distribution (Vd) and half-life (t1/2) of MKC after oral administration were significantly lower in diabetic than in healthy rats (21, 31 and 29% respectively). After the i.v. dose, the change in blood glucose concentration was not significant in either healthy or diabetic rats. After the oral dose, the decrease in blood glucose concentration was significant, reaching a maximum decrease from baseline of 24% in healthy rats and 15% in diabetic rats. The results suggest that a first-pass effect is crucial for the hypoglycemic activity of MKC, indicating that a metabolite of MKC and/or interference with metabolism and glucose transport is responsible.

Introduction: Distribution coefficient (D) is useful parameter for evaluating drugs permeability properties across biological membranes, which are of importance for drugs bioavailability. Given that bile acids are intensively studied as drug permeation-modifying and -solubilizing agents, the aim of this study was to estimate the influence of sodium salts of cholic (CA), deoxycholic (DCA) and 12-monoketocholic acids (MKC) on distribution coefficient of simvastatin (SV) (lactone [SVL] and acid form [SVA]) which is a highly lipophilic compound with extremely low water solubility and bioavailability.Methods: LogD values of SVA and SVL with or without bile salts were measured by liquid-liquid extraction in n-octanol/buffer systems at pH 5 and 7.4. SV concentrations in aqueous phase were determined by HPLC-DAD. Chem3D Ultra program was applied for computation of physico-chemical properties of analyzed compounds and their complexes.Results: Statistically significant decrease in both SVA and SVL logD was observed for all three studied bile salts at both selected pH. MKC exerted the most pronounced effect in the case of SVA while there were no statistically significant differences between observed bile salts for SVL. The calculated physico-chemical properties of analyzed compounds and their complexes supported experimental results.Conclusions: Our data indicate that the addition of bile salts into the n-octanol/buffer system decreases the values of SV distribution coefficient at both studied pH values. This may be the result of the formation of hydrophilic complexes increasing the solubility of SV that could consequently impact the pharmacokinetic parameters of SV and the final drug response in patients.

We previously designed, developed and characterized a novel microencapsulated formulation as a platform for the targeted delivery of Probucol (PB) in an animal model of Type 2 Diabetes.The objective of this study is to optimize this platform by incorporating Chenodeoxycholic acid (CDCA), a bile acid with good permeation-enhancing properties, and examine its effect in vitro. Using sodium alginate (SA), we prepared PB-SA (control) and PB-CDCA-SA (test) microcapsules.CDCA resulted in better structural and surface characteristics, uniform morphology, and stable chemical and thermal profiles, while size and rheological parameters remained unchanged. PB-CDCA-SA microcapsules showed good excipients' compatibilities, as evidenced by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy studies. CDCA reduced microcapsule swelling at pH 7.8 at both 37 °C and 25 °C and improved PB-release.CDCA improved the characteristics and release properties of PB-microcapsules and may have potential in the targeted oral delivery of PB.

BACKGROUND: The well-known functions of bile acids (BAs) are the emulsification and absorption of lipophilic xenobiotics. However, the emerging evidences in the past decade showed that BAs act as signaling molecules that not only autoregulate their own metabolism and enterohepatic recirculation, but also as important regulators of integrative metabolism by activating nuclear and membrane-bound G protein-coupled receptors. The present review was to get insight into the role of maintenance of BA homeostasis and BA signaling pathways in development and management of hepatobiliary and intestinal diseases. DATA SOURCES: Detailed and comprehensive search of PubMed and Scopus databases was carried out for original and review articles. RESULTS: Disturbances in BA homeostasis contribute to the development of several hepatobiliary and intestinal disorders, such as non-alcoholic fatty liver disease, liver cirrhosis, cholesterol gallstone disease, intestinal diseases and both hepatocellular and colorectal carcinoma. CONCLUSION: Further efforts made in order to advance the understanding of sophisticated BA signaling network may be promising in developing novel therapeutic strategies related not only to hepatobiliary and gastrointestinal but also systemic diseases. (Hepatobiliary Pancreat Dis Int 2015;14:18-33)

The interaction of aqueous solutions of stevioside and bile acids with cardioactive drugs was studied in rats by registering changes in their electrocardiograms (ECG). Wistar rats of both sexes received daily doses of 20 mg/kg (i.p.) of an aqueous solution of stevioside or physiological solution (controls), then were narcotized with urethane and connected to the ECG apparatus for the first recording. The jugular vein was prepared and connected to an infusion pump to administer one of the drugs: adrenaline (0.1 mg/ml), verapamil (2.5 mg/ml) or metoprolol (1 mg/ml) to rats in both groups, while recording their ECGs. In the second part of the study, the animals were treated in the same way but instead of the stevioside solution received a single dose of 4 mg/kg of monoketocholic acid methyl ester (ME) or sodium salt of the same bile acid (MKHNa), 30 minutes before cardioactive drug infusion. The infusion rate of cardioactive drugs was 0.2 ml/min, except for verapamil (0.1 ml/min). The events observed on ECG recordings were the first myocardial reaction to drug infusion, the second longer-lasting reaction (observed as more extended extrasystoles, decrease in intensity of the QRS complex, or changes in heart rate frequency), and toxicity effect. In the control animals, adrenaline induced a decrease in heart rate frequency at a dose of 0.094 mg/kg, while with stevioside-pretreated rats this effect appeared significantly earlier (at a dose of 0.018 mg/kg). No toxic effect of adrenaline was observed, either in control or stevioside-pretreated group. Bile acids caused no changes in myocardial reaction to adrenaline. Only in the group of animals that received MKHNa, a significant decrease in the QRS complex was observed. Finally, the infusion of stevioside to intact animals at doses of 45 and 55 mg/kg caused no significant changes in the ECG patterns. The myocardial reaction to metoprolol remained unchanged in rats of all groups when compared with controls except for a mild decrease in heart rate frequency. Stevioside induced/produced a significant increase in myocardial sensitivity to verapamil, but no toxic effect was observed in any of the cases. A similar conclusion also holds for the interaction with MKHNa, whereas ME caused an increase in the toxicity of verapamil.

In this article, the methods of isolation and determination of bile acids are reviewed. Methods for separation of bile acids from cattle and pig bile are given in detail. Isolation of a mixture of cholic acid and deoxycholic acids from cattle bile and their subsequent purification are described. The isolation and purification of hyodeoxycholic acid and other components of pig bile are also included. Methods for the determination of bile acids in various biological samples are reviewed, including enzyme assays, radioimmunoassay, enzyme immunoassay and chromatographic methods. Among chromatographic methods, separation and determination of bile acids by thin-layer chromatography, gas chromatography and high performance liquid chromatography are reviewed. Particular attention is given to the use of high performance liquid chromatography since this has recently been the most commonly applied method for the separation and determination of bile acids.

The biosynthesis of bile acids in mammalian liver and its regulation, together with the physiological role of bile acids, are reviewed in this article. Bile acids are biosynthesized from cholesterol in hepatocytes. Several steps are involved including epimerisation of the 3beta-hydroxyl group, reduction of the delta4 double bond to the 5beta-H structural arrangement, introduction of alpha-hydroxyl groups at C7 or C7 and C12 and, finally, oxidative degradation of the side chain by three carbon atoms. This gives the primary bile acids, cholic and chenodeoxycholic acids. Cholesterol-7alpha-hydroxylation is the rate determining step in the biosynthesis of cholic and chenodeoxycholic acids. Feedback regulation of cholesterol biosynthesis occurs by various mechanisms including termination of the synthesis of specific cytochromes P-450, modulation of specific cytosol proteins, short-term changes in the process of phosphorylation-dephosphorylation and changes in the capacity of the cholesterol pool as a substrate. Prior to being exported from the liver, bile acids are conjugated with glycine and taurine to produce the bile salts. After excretion into the intestinal tract, primary bile acids are partly converted to secondary bile acids, deoxycholic and lithocholic acids, by intestinal microorganisms. The majority of bile acids is absorbed from the intestinal tract and returned to the liver via the portal blood, so that only a small fraction is excreted in the feces. Bile acids returned to the liver can be reconjugated and reexcreted into the bile in the process of enterohepatic recycling. In addition to the physiological function of emulsifying lipids in the intestinal tract, bile acids are particularly important in respect of their ability to dissolve and transport cholesterol in the bile.

This article surveys chemical transformations of selected bile acids. Chemical transformations were initially carried out with the aim of determining the structure of bile acids. More recently they have been concerned with bile acid interconversions as well as with the synthesis of steroid hormones, vitamins and therapeutc agents. Studies of similarities and differences in the biosynthesis of bile acids from cholesterol have occupied many researches. However, this article reviews only papers dealing with the synthesis of potential intermediates in the biosynthesis of bile acids. Steroid hormones such as pregnenolone, progesterone and testosterone are synthesized from methyl thiodeoxycholate whereas cortisone is synthesized from methyl deoxycholiate. Numerous papers and patents devoted to the synthesis of ursodeoxycholic acid from cholic or chenodeoxycholic acid testify to its effectiveness in the treatment of cholelithiasis. Chenodeoxycholic acid appears to be an excellent precursor in the synthesis of steroid plant growth regulators, as well as in the synthesis of metabolites and vitamin D analogues. Chirality of bile acids has been exploited in the synthesis of cyclic and acyclic receptors and solvents. Cholic and deoxycholic acids have been used to create new macrocyclic structures which show different capacities to bind and transport other compounds. Another important trend in the chemistry of bile acids is their application in combinatorial chemistry.

Introduction Urinary tract infections (UTI) are among the most common infectious diseases affecting all age groups, from infants to the elderly. The majority of these infections occur in otherwise healthy individuals who present with symptoms of acute uncomplicated bacterial cystitis or pyelonephritis. Certain patient populations with complicated conditions are at increased risk for acquiring infection or failing therapy. Forty to 50% of adult women have a history of at least one urinary tract infection. Diagnosis and classification of UTI Although there are general guidelines concerning diagnosis and classification of urinary tract infections, there are wide variations in clinical practice. There are both errors which are frequently committed and mysteries that are still unsolved. Active management is important because under some circumstances urinary tract infections may cause permanent renal scarring. Imaging procedures are a cornerstone for critical evaluation of urinary tract infections, but avoidance of investigative routines will allow a marked saving in terms of costs and in terms of unnecessary radiation and psychological stress to the patient.