Epidemiology of Cytochrome P450-mediated Drug-Drug Interactions

Drug-drug interactions (DDIs) comprise an important cause of adverse drug reactions leading to excess hospitalizations. Drug metabolism is catalyzed by 75% by cytochrome P450 (CYP) enzymes and thus they are often involved in pharmacokinetic DDIs. In general, DDIs are studied in randomized controlled clinical trials in selected study populations. The overall aim of the present studies was to perform observational pharmacoepidemiological surveys on CYP-mediated DDIs in diseases important at the population level. The prevalence of co-administrations of four prodrugs (losartan, codeine, tramadol, and clopidogrel), three sulphonylureas (glibenclamide, glimepiride, and glipizide), or two statins (lovastatin and simvastatin) with well established agents altering CYP activity, as well as of statins with fibrates, was studied in Finland utilizing data from a university hospital medication database (inpatients) and the National Prescription Register of the Social Insurance Institution of Finland, Kela (outpatients). Clinical consequences of potential DDIs were estimated by reviewing laboratory data, and information from hospital care and cause-of-death registers. Concomitant use of study substrates with interacting medication was detected in up to one fifth of patients in both hospital and community settings. Potential CYP3A4 interactions in statin users did not manifest in clear adverse laboratory values but pharmacodynamic DDIs between statins and fibrates predisposed patients to muscular toxicity. Sulphonylurea DDIs with CYP2C9 inhibitors increased the risk of hypoglycaemia. CYP3A4 inhibitor use with clopidogrel was not associated with significant changes in mortality but non-fatal thrombosis and haemorrhage complications were seen less often in this group. Concomitant administration of atorvastatin with clopidogrel moderately attenuated the antithrombotic effect by clopidogrel. The overall mortality was increased in CYP3A4 inducer and clopidogrel co-users. Atorvastatin used concomitantly with prodrug clopidogrel seems to be beneficial in terms of total and LDL cholesterol concentrations, and overall mortality compared with clopidogrel use without interacting medication. In conclusion, CYP-mediated DDIs are a common and often unrecognized consequence of irrational drug prescribing.

Studies on 68Ga-Based Agents for PET Imaging of Cancer and Inflammation

Studies on ⁶⁸Ga-Based Agents for PET Imaging of Cancer and Inflammation Positron emission tomography (PET) is based on the use of radiolabeled agents and facilitates in vivo imaging of biological processes, such as cancer. Because the detection of cancer is demanding and is often obscured by inflammation, there is a demand for better PET imaging agents. The aim was to preliminarily evaluate new PET agents for imaging cancer and inflammation using experimental models. ⁶⁸Ga-chloride and peptides, ⁶⁸Ga-labeled through 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), targeting matrix metalloproteinase-9 (MMP-9) were tested for tumor imaging. In addition, a ⁶⁸Ga-DOTA-conjugated peptide targeting vascular adhesion protein-1 (VAP-1), was tested for inflammation imaging. The ⁶⁸Ga-based imaging agents described here showed potential features by passing the essential in vitro tests, proceeding further to preclinical in vivo evaluation and being able to visualize the target. The target uptake and target-to-background ratios of ⁶⁸Ga-based agents were, however, not optimal. ⁶⁸Ga-chloride showed slow clearance caused by its binding to blood transferrin. In the case of ⁶⁸Ga-DOTA-peptides low in vivo stability and/or low lipophilicity led to too rapid blood clearance and urinary excretion. The properties of ⁶⁸Ga-labeled peptides are modifiable, as shown with matrix metalloproteinase-9 targeting ligands. In the conclusion of this PhD thesis, ⁶⁸Ga-based agents for PET imaging of cancer and inflammation could be applied in the development of drugs, earlier diagnostics and following-up of the efficacy of therapies.

Studies on Neuromuscular Blocking Agents and Their Antagonists During Anaesthesia

Neuromuscular blocking agents (NMBAs) are widely used in clinical anaesthesia and emergency medicine. Main objectives are to facilitate endotracheal intubation and to allow surgery by reducing muscle tone and eliminating sudden movements, which may otherwise lead to trauma and complications. The most commonly used NMBAs are non-depolarizing agents with a medium duration of action, such as rocuronium and cisatracurium. They bind to the acetylcholine receptors in the neuromuscular junction, thus inhibiting the depolarization of the postsynaptic (muscular) membrane, which is a prerequisite for muscle contraction to take place. Previously, it has been assumed that nitrous oxide (N2O), which is commonly used in combination with volatile or intravenous anaesthetics during general anaesthesia, has no effect on NMBAs. Several studies have since claimed that N2O in fact does increase the effect of NMBAs when using bolus administration of the relaxant. The effect of N2O on the infusion requirements of two NMBAs (rocuronium and cisatracurium) with completely different molecular structure and pharmacological properties was assessed. A closed-loop feedback controlled infusion of NMBA with duration of at least 90 minutes at a 90% level of neuromuscular block was used. All patients received total intravenous anaesthesia (TIVA) with propofol and remifentanil. In both studies the study group (n=35) received N2O/Oxygen and the control group (n=35) Air/Oxygen. There were no significant differences in the mean steady state infusion requirements of NMBA (rocuronium in Study I; cisatracurium in Study II) between the groups in either study. In Study III the duration of the unsafe period of recovery after reversal of rocuronium-induced neuromuscular block by using neostigmine or sugammadex as a reversal agent was analyzed. The unsafe period of recovery was defined as the time elapsed from the moment of no clinical (visual) fade in the train-of-four (TOF) sequence until an objectively measured TOF-ratio of 0.90 was achieved. The duration of these periods were 10.3 ± 5.5 and 0.3 ± 0.3 min after neostigmine and sugammadex, respectively (P < 0.001). Study IV investigated the possible effect of reversal of a rocuronium NMB by sugammadex on depth of anaesthesia as indicated by the bispectral index and entropy levels in thirty patients. Sugammadex did not affect the level of anaesthesia as determined by EEG-derived indices of anaesthetic depth such as the bispectral index and entropy.

Bonding of Composite Resin to Alumina and Zirconia Ceramics with Special Emphasis on Surface Conditioning and Use of Coupling Agents

Dental oxide ceramics have been inspired by their biocompability and mechanical properties which have made durable all-ceramic structures possible. Clinical longevity of the prosthetic structures is dependent on effective bonding with luting cements. As the initial shear bond strength values can be comparable with several materials and procedures, long-term durability is affected by ageing. Aims of the current study were: to measure the shear bond strength of resin composite-to-ceramics and to evaluate the longevity of the bond; to analyze factors affecting the bond, with special emphasis on: the form of silicatization of the ceramic surface; form of silanization; type of resin primer and the effect of the type of the resin composite luting cement; the effect of ageing in water was studied regarding its effect to the endurance of the bond. Ceramic substrates were alumina and yttrium stabilized zirconia. Ceramic conditioning methods included tribochemical silicatization and use of two silane couplings agents. A commercial silane primer was used as a control silane. Various combinations of conditioning methods, primers and resin cements were tested. Bond strengths were measured by shear bond strength method. The longevity of the bond was generally studied by thermocycling the materials in water. Additionally, in one of the studies thermal cycling was compared with long-term water storaging. Results were analysed statistically with ANOVA and Weibull analysis. Tribochemical treatment utilizing air pressure of 150 kPa resulted shear bond strengths of 11.2 MPa to 18.4 MPa and air pressure of 450 kPa 18.2 MPa to 30.5 MPa, respectively. Thermocycling of 8000 cycles or four years water storaging both decreased shear bond strength values to a range of 3.8 MPa to 7.2 MPa whereas initial situation varied from 16.8. Mpa to 23.0 MPa. The silane used in studies had no statistical significance. The use of primers without 10-MDP resulted spontaneous debonding during thermocycling or shear bond strengths below 5 MPa. As conclusion, the results showed superior long-term bonding with primers containing 10-MDP. Silicatization with silanizing showed improved initial shear bond strength values which considerably decreased with ageing in water. Thermal cycling and water storing for up to four years played the major role in reduction of bond strength, which could be due to thermal fatigue of the bonding interface and hydrolytic degradation of the silane coupled interface.

IT service catalog : a case study of the implementation need in a Pan-Nordic Insurance Company

IT service catalog is an increasingly important issue as many IT organizations have been realizing it as a central communication and visualization tool to bridge the gap between IT and the business. This study reviews relevant literature on IT service catalog and related issues on IT services delivery. Furthermore, the study shows how IT service catalog can enhance IT effectiveness as well as provide more benefits when integrating with Configuration Management Database. In order to analyze whether IT service catalog is needed to be implemented in a Pan-Nordic Insurance Company, this study also investigates the current IT services delivery of a case study. The findings of the study show the problems in the current situation of IT services delivery in the case. The characteristics of IT service catalog are recommended in order to help with the mentioned flaws.

Configuration management process improvement : a case study of a Pan-Nordic insurance company

Configuration management is often seen as an enabler for the main IT Service Management (ITSM) processes such as Incident and Problem management. A decent level of quality of IT configuration data is required in order to carry out routines of these processes. This case study examines the state of configuration management in a multinational organization and aims at identification of methods for its improvement. The author has stayed five months with this company in order to collect different sources of evidence and to make observations. The main source of data for this study is interviews with some of the key employees of the assigned organization who are involved into the ITSM processes. This study concludes the maturity level of the existing configuration management process to be repeatable but intuitive, and outlines the principal requirements for its improvement. A match between the requirements identified in the organization and the requirements stated in the ISO/IEC 20000 standard indicates the possibility of adopting ITIL guidelines as a method for configuration management process improvement. The outcome of the study presents a set of recommendations for improvement that considers the process, the information model and the information system for configuration management in the case organization.

Fibrinonecrotic enteritis of piglets in a commercial farm: a postmortem study of the prevalence and the role of lesion associated agents Isospora suis and Clostridium perfringens

The objectives were to determine the prevalence of fibrinonecrotic enteritis (FNE) on a farrow-to-finish farm of 1,000 sows, to categorize the pathological changes, and to to investigate the lesion associated agents Isospora suis and Clostridium perfringens. Causes of preweaning mortality (PWM) were classified into 8 categories including FNE. Obtained data were evaluated for statistical significance by adjusted Chi-square analysis. Samples of FNE were taken for complementary studies including a PCR technique for genotyping toxin genes of Clostridium perfringens from gut samples fixed in 10% neutral formalin. From 3,153 piglets examined, less than 1% was classified as FNE. FNE prevalence increased progressively from the first to the third week, the last differing statistically from the others. Eighty percent of gut samples with FNE lesions were positive to Isospora suis, when examined by PCR from 9 severe FNE lesions detected 7 positive samples only for a toxin gene, characteristic of C. perfringens type-A.

Matched case-control study evaluating the frequency of the main agents associated with neonatal diarrhea in piglets

A case-control study was carried out in litters of 1 to 7-day-old piglets to identify the main infectious agents involved with neonatal diarrhea in pigs. Fecal samples (n=276) from piglets were collected on pig farms in the State of Rio Grande do Sul, Brazil, from May to September 2007. Litters with diarrhea were considered cases (n=129) and normal litters (n=147) controls. The samples were examined by latex agglutination test, PAGE, conventional isolating techniques, ELISA, PCR, and microscopic methods in order to detect rotavirus, bacterial pathogens (Escherichia coli, Clostridium perfringens type A and C, and Clostridium difficile), and parasites (Coccidian and Cryptosporidium spp.). Outbreaks of diarrhea were not observed during sampling. At least one agent was detected in fecal samples on 25 out of 28 farms (89.3%) and in 16 farms (57.1%) more than one agent was found. The main agents diagnosed were Coccidia (42.86%) and rotavirus (39.29%). The main agents identified in litters with diarrhea were Clostridium difficile (10.6%), Clostridium perfringens type A (8.8%) and rotavirus (7.5%); in control litters, Clostridium difficile (16.6%) and Coccidian (8.5%). Beta hemolytic Escherichia coli and Clostridium perfringens type C were not detected. When compared with controls, no agent was significantly associated with diarrhea in case litters. These findings stress the need for caution in the interpretation of laboratorial diagnosis of mild diarrhea in neonatal pigs, as the sole detection of an agent does not necessarily indicate that it is the cause of the problem.

Accountability and corruption : a study into political institutions as referees between principals and agents

Representativ demokrati innebär att medborgare istället för att själv göra beslut i frågor som angår dem, ofta delegerar dylikt beslutsfattande till representanter. Det här betyder att viktiga beslut görs av personer som medborgarna i allmänhet inte känner speciellt väl, och i vars ageranden medborgarna endast har lite insyn. Vanliga medborgare och deras representanter har därtill ofta mycket olika intressen, d.v.s. har olika syn på vad som är viktigt. Representanterna har följaktligen både möjligheter och incitament att missbruka den makt som anförtrotts dem, bl.a. genom korrupt verksamhet. Denna avhandling analyserar mekanismer genom vilka korruption bland representanter kan förebyggas, och (då korrupta handlingar redan ägt rum) upptäckas. Avhandlingen granskar mekanismer som a) ger medborgare och andra ansvarsutkrävare mer information om representanternas målsättningar och ageranden, b) som tvingar representanterna att rättfärdiga sina ageranden gentemot medborgare och andra ansvarsutkrävare, och c) som gör det möjligt för medborgare och andra ansvarsutkrävare att straffa representanter som agerat korrupt. Avhandlingen hävdar att tillämpandet av dylika mekanismer minskar lockelsen för och möjligheterna att engagera sig i korrupta handlingar. Avhandlingen studerar de mekanismer för ansvarsutkrävande som skapas genom politiskt institutionsbyggande. Bl.a. analyseras i vilken grad olika valsystem och typer av maktfördelning gör det möjligt att hålla representanter till svars, och därmed förhindra och upptäcka korruption. Sambandet mellan institutionsbyggande, möjligheter till ansvarsutkrävande och förekomst av korruption studeras på såväl makro- som mikronivå. Studien på makronivå inkluderar ett flertal länder och analyserar sambandet med hjälp av statistisk analys. Studien på mikronivå däremot består av två fallstudier (Österrike och Botswana) och utgör en djupdykning i dessa länders politiska institutioner, möjligheter till ansvarsutkrävande inom ramen för institutionerna, och följder i form av korruption.

Agents that affect cAMP levels or protein kinase A activity modulate memory consolidation when injected into rat hippocampus but not amygdala

Male Wistar rats were trained in one-trial step-down inhibitory avoidance using a 0.4-mA footshock. At various times after training (0, 1.5, 3, 6 and 9 h for the animals implanted into the CA1 region of the hippocampus; 0 and 3 h for those implanted into the amygdala), these animals received microinfusions of SKF38393 (7.5 µg/side), SCH23390 (0.5 µg/side), norepinephrine (0.3 µg/side), timolol (0.3 µg/side), 8-OH-DPAT (2.5 µg/side), NAN-190 (2.5 µg/side), forskolin (0.5 µg/side), KT5720 (0.5 µg/side) or 8-Br-cAMP (1.25 µg/side). Rats were tested for retention 24 h after training. When given into the hippocampus 0 h post-training, norepinephrine enhanced memory whereas KT5720 was amnestic. When given 1.5 h after training, all treatments were ineffective. When given 3 or 6 h post-training, 8-Br-cAMP, forskolin, SKF38393, norepinephrine and NAN-190 caused memory facilitation, while KT5720, SCH23390, timolol and 8-OH-DPAT caused retrograde amnesia. Again, at 9 h after training, all treatments were ineffective. When given into the amygdala, norepinephrine caused retrograde facilitation at 0 h after training. The other drugs infused into the amygdala did not cause any significant effect. These data suggest that in the hippocampus, but not in the amygdala, a cAMP/protein kinase A pathway is involved in memory consolidation at 3 and 6 h after training, which is regulated by D1, ß, and 5HT1A receptors. This correlates with data on increased post-training cAMP levels and a dual peak of protein kinase A activity and CREB-P levels (at 0 and 3-6 h) in rat hippocampus after training in this task. These results suggest that the hippocampus, but not the amygdala, is involved in long-term storage of step-down inhibitory avoidance in the rat.

Efficacy, safety, quality control, marketing and regulatory guidelines for herbal medicines (phytotherapeutic agents)

This review highlights the current advances in knowledge about the safety, efficacy, quality control, marketing and regulatory aspects of botanical medicines. Phytotherapeutic agents are standardized herbal preparations consisting of complex mixtures of one or more plants which contain as active ingredients plant parts or plant material in the crude or processed state. A marked growth in the worldwide phytotherapeutic market has occurred over the last 15 years. For the European and USA markets alone, this will reach about $7 billion and $5 billion per annum, respectively, in 1999, and has thus attracted the interest of most large pharmaceutical companies. Insufficient data exist for most plants to guarantee their quality, efficacy and safety. The idea that herbal drugs are safe and free from side effects is false. Plants contain hundreds of constituents and some of them are very toxic, such as the most cytotoxic anti-cancer plant-derived drugs, digitalis and the pyrrolizidine alkaloids, etc. However, the adverse effects of phytotherapeutic agents are less frequent compared with synthetic drugs, but well-controlled clinical trials have now confirmed that such effects really exist. Several regulatory models for herbal medicines are currently available including prescription drugs, over-the-counter substances, traditional medicines and dietary supplements. Harmonization and improvement in the processes of regulation is needed, and the general tendency is to perpetuate the German Commission E experience, which combines scientific studies and traditional knowledge (monographs). Finally, the trend in the domestication, production and biotechnological studies and genetic improvement of medicinal plants, instead of the use of plants harvested in the wild, will offer great advantages, since it will be possible to obtain uniform and high quality raw materials which are fundamental to the efficacy and safety of herbal drugs.

Antiretroviral agents and acid-base balance at delivery of the neonate

Limited evidence is available regarding antiretroviral (ARV) safety for uninfected infants exposed to these drugs in utero. Our objective was to determine if ARV administered to pregnant women is associated with decreasing umbilical arterial pH and base excess in uninfected infants. A prospective study was conducted on 57 neonates divided into three groups: ZDV group, born to mothers taking zidovudine (N = 20), triple therapy (TT) group, born to mothers taking zidovudine + lamivudine + nelfinavir (N = 25), and control group (N = 12), born to uninfected mothers. Umbilical cord blood was used to determine umbilical artery gases. A test was performed to calculate the sample by comparing means by the unpaired one-tailed t-test, with a = 0.05 and ß = 20%, indicating the need for a sample of 18 newborn infants for the study groups to detect differences higher than 20%. The control and ARV groups were similar in gestational age, birth weight, and Apgar scores. Values of pH, pCO2, bicarbonate, and base excess in cord arterial blood obtained at delivery from the newborns exposed to TT were 7.23, 43.2 mmHg, 19.5 mEq/L, and -8.5 nmol/L, respectively, with no significant difference compared to the control and ZDV groups. We conclude that intrauterine exposure to ARV is not associated with a pathological decrease in umbilical arterial pH or base excess. While our data are reassuring, follow-up is still limited and needs to be continued into adulthood because of the possible potential for adverse effects of triple antiretroviral agents.

Identification of fungemia agents using the polymerase chain reaction and restriction fragment length polymorphism analysis

Prompt and specific identification of fungemia agents is important in order to define clinical treatment. However, in most cases conventional culture identification can be considered to be time-consuming and not without errors. The aim of the present study was to identify the following fungemia agents: Candida albicans, Candida parapsilosis, Candida tropicalis, Candida glabrata, Cryptococcus neoformans, Cryptococcus gattii, and Histoplasma capsulatum using the polymerase chain reaction and restriction fragment length polymorphism analysis (PCR/RFLP). More specifically: a) to evaluate 3 different amplification regions, b) to investigate 3 different restriction enzymes, and c) to use the best PCR/RFLP procedure to indentify 60 fungemia agents from a culture collection. All 3 pairs of primers (ITS1/ITS4, NL4/ITS5 and Primer1/Primer2) were able to amplify DNA from the reference strains. However, the size of these PCR products did not permit the identification of all the species studied. Three restriction enzymes were used to digest the PCR products: HaeIII, Ddel and Bfal. Among the combinations of pairs of primers and restriction enzymes, only one (primer pair NL4/ITS5 and restriction enzyme Ddel) produced a specific RFLP pattern for each microorganism studied. Sixty cultures of fungemia agents (selected from the culture collection of Fundação de Medicina Tropical do Amazonas - FMTAM) were correctly identified by PCR/RFLP using the prime pair NL4/ITS5 and Ddel. We conclude that the method proved to be both simple and reproducible, and may offer potential advantages over phenotyping methods.

Evaluation of anti-Wnt/β-catenin signaling agents by pGL4-TOP transfected stable cells with a luciferase reporter system

Refractory and relapsed leukemia is a major problem during cancer therapy, which is due to the aberrant activation of Wnt/β-catenin signaling pathway. Activation of this pathway is promoted by wingless (Wnt) proteins and induces co-activator β-catenin binding to lymphoid enhancer factor (LEF)/T-cell factor protein (TCF). To provide a convenient system for the screening of anti-Wnt/β-catenin agents, we designed a bi-functional pGL4-TOP reporter plasmid that contained 3X β-catenin/LEF/TCF binding sites and a selectable marker. After transfection and hygromycin B selection, HEK 293-TOP and Jurkat-TOP stable clones were established. The luciferase activity in the stable clone was enhanced by the recombinant Wnt-3A (rWnt-3A; 100-400 ng/mL) and GSK3β inhibitor (2’Z,3’E)-6-bromoindirubin-3’-oxime (BIO; 5 µM) but was inhibited by aspirin (5 mM). Using this reporter model, we found that norcantharidin (NCTD; 100 µM) reduced 80% of rWnt-3A-induced luciferase activity. Furthermore, 50 µM NCTD inhibited 38% of BIO-induced luciferase activity in Jurkat-TOP stable cells. Employing ³H-thymidine uptake assay and Western blot analysis, we confirmed that NCTD (50 µM) significantly inhibited proliferation of Jurkat cells by 64%, which are the dominant β-catenin signaling cells and decreased β-catenin protein in a concentration-dependent manner. Thus, we established a stable HEK 293-TOP clone and successfully used it to identify the Wnt/β-catenin signaling inhibitor NCTD.