Development of a Population Pharmacokinetic Model To Describe Azithromycin Whole-Blood and Plasma Concentrations over Time in Healthy Subjects

ABSTRACT Azithromycin (AZI), a broad-spectrum antibiotic, accumulates in polymorphonuclear cells and peripheral blood mononuclear cells. The distribution of AZI in proinflammatory cells may be important to the anti-inflammatory properties. Previous studies have described plasma AZI pharmacokinetics. The objective of this study was to describe the pharmacokinetics of AZI in whole blood (concentration in whole blood [ C b ]) and plasma (concentration in plasma [ C p ]) of healthy subjects. In this study, 12 subjects received AZI (500 mg once a day for 3 days). AZI C b and C p were quantified in serial samples collected up to 3 weeks after the last dose and analyzed using noncompartmental and compartmental methods. After the last dose, C b was greater than C p . Importantly, C b , but not C p , was quantifiable in all but one subject at 3 weeks. The blood area under the curve during a 24-h dosing interval (AUC 24 ) was ∼2-fold greater than the plasma AUC 24 , but simulations suggested that C b was not at steady state by day 3. Upon exploration of numerous models, an empirical 3-compartment model adequately described C p and C b , but C p was somewhat underestimated. Intercompartmental clearance (CL; likely representing cells) was lower than apparent oral CL (18 versus 118 liters/h). Plasma, peripheral, and cell compartmental volumes were 439 liters, 2,980 liters, and 3,084 liters, respectively. Interindividual variability in CL was low (26.2%), while the volume of distribution variability was high (107%). This is the first report to describe AZI C b in healthy subjects, the distribution parameters between C p and C b , and AZI retention in blood for up to 3 weeks following 3 daily doses. The model can be used to predict C b from C p for AZI under various dosing regimens. (This study has been registered at ClinicalTrials.gov under registration no. NCT01026064.

Induction of MDR1 gene expression by anthracycline analogues in a human drug resistant leukaemia cell line

The effects of 4-demethoxydaunorubicin (idarubicin, IDA) and MX2, a new morpholino-anthracycline, on up-regulation of the MDR1 gene in the low-level multidrug resistant (MDR) cell line CEM/A7R were compared at similar concentrations (IC10, IC50and IC90) over a short time exposure (4 and 24 h). The chemosensitivity of each drug was determined by a 3-day cell growth inhibition assay. Compared with epirubicin (EPI), IDA and MX2 were 17- and eightfold more effective in the CEM/A7R line respectively. No cross-resistance to 5-FU was seen in the CEM/A7R line. Verapamil (5 μM) and PSC 833 (1 μM), which dramatically reversed resistance to EPI in the CEM/A7R line, had no sensitizing effect on the resistance of this line to MX2, but slightly decreased resistance to IDA. The sensitivity to 5-FU was unchanged by these modulators. The induction of MDR1 mRNA expression by IDA, MX2 and 5-FU was analysed by Northern blotting and semiquantitatively assessed by scanning Northern blots on a phosphorimager. The relative level of MDR1 expression was expressed as a ratio of MDR1 mRNA to the internal RNA control glyceraldehyde-3-phosphate dehydrogenase (GAPDH). IDA, MX2 and 5-FU differentially up-regulated MDR1 mRNA in the CEM/A7R line in a dose-dependent manner. Both IDA and MX2 induced MDR1 expression within 4 h. 5-FU up-regulated MDR1 expression only when drug exposure was prolonged to 24 h. Based on MRK 16 binding, flow cytometric analysis of P-glycoprotein (Pgp) expression paralleled the increase in MDR1 mRNA levels. For the three anthracyclines, the increase in MDR1 expression was stable in cells grown in the absence of drug for more than 3 weeks after drug treatment. The induction of MDR1 expression by 5-FU was transient, associated with a rapid decrease in the increased Pgp levels which returned to baseline 72 h after the removal of 5-FU. This study demonstrates that MDR1 expression can be induced by analogues of anthracyclies not pumped by Pgp, and that this induction appears to be stable despite a 3-week drug-free period. © 1999 Cancer Research Campaig

Single-step doxorubicin-selected cancer cells overexpress the ABCG2 drug transporter through epigenetic changes

Understanding the mechanisms of multidrug resistance (MDR) could improve clinical drug efficacy. Multidrug resistance is associated with ATP binding cassette (ABC) transporters, but the factors that regulate their expression at clinically relevant drug concentrations are poorly understood. We report that a single-step selection with low doses of anti-cancer agents, similar to concentrations reported in vivo, induces MDR that is mediated exclusively by ABCG2. We selected breast, ovarian and colon cancer cells (MCF-7, IGROV-1 and S-1) after exposure to 14 or 21 nM doxorubicin for only 10 days. We found that these cells overexpress ABCG2 at the mRNA and protein levels. RNA interference analysis confirmed that ABCG2 confers drug resistance. Furthermore, ABCG2 upregulation was facilitated by histone hyperacetylation due to weaker histone deacetylase 1-promoter association, indicating that these epigenetic changes elicit changes in ABCG2 gene expression. These studies indicate that the MDR phenotype arises following low-dose, single-step exposure to doxorubicin, and further suggest that ABCG2 may mediate early stages of MDR development. This is the first report to our knowledge of single-step, low-dose selection leading to overexpression of ABCG2 by epigenetic changes in multiple cancer cell lines

LIFE CYCLE ASSESSMENT IN HEALTHCARE SYSTEM OPTIMIZATION. INTRODUCTION

Article describes the life cycle assessment method and introduces opportunities for method performance in healthcare system settings. LSA draws attention to careful use of resources, environmental, human and social responsibility. Modelling of environmental and technological inputs allows optimizing performance of the system. Various factors and parameters that may influence effectiveness of different sectors in healthcare system are detected. Performance optimization of detected parameters could lead to better system functioning, higher patient safety, economic sustainability and reduce resources consumption

Comparison of efficacy of extracorporeal magnetic innervation and Kegel exercises for stress urinary incontinence in adult women: Study protocol for a randomized controlled trial

Stress urinary incontinence (SUI) is defined as a complaint of inadvertent loss of urine occurring as a result of an increase in intraabdominal pressure. Strong evidence supports the use of pelvic floor muscle training (PFMT) as the first-line conservative treatment for SUI. Extracorporeal magnetic stimulation (EMS) is a noninvasive, effective, acceptable, and safe therapeutic modality for SUI. Although PFMT and EMS share most of their influences on the pathophysiology of SUI, it is unclear whether one of these routinely used treatment modalities is superior to another in terms of improvement of clinical outcomes or cost-effectiveness. To the best of our knowledge, no randomized controlled trials have so far directly compared PFMT with EMS. Our aim here is to describe a protocol for such a study. This will be a parallel-group, single-blind, randomised controlled trial compliant with the SPIRIT, CONSORT, and TIDieR reporting guidelines. Participants will be women aged 18 to 65 years who have previously given at least one vaginal delivery (at least 12 months before joining the study) who present with symptoms of SUI lasting at least 6 months yet have not previously received treatment for it. In the first study arm, patients will receive an eight-week, high-intensity, home-based Kegel exercises regimen. In the second study arm, the treatment scheme will consist of 2 sessions of EMS per week for a total of eight weeks. The primary outcome will be effectiveness of treatment as measured by the International Consultation on Incontinence Questionnaire Urinary Incontinence- Short Form overall score, eight weeks, three months, and six months after commencement of treatment

Cardiometabolic profiles in children and adults with overweight and obesity and down syndrome

Individuals with Down syndrome (DS) are at increased risk for being overweight/obese, but the associated cardiometabolic risk (CR) is not clear. Cross-sectional anthropometric and clinical laboratory data from a multi-site, international cohort of individuals with DS were analyzed to determine cardiometabolic risk by reporting observed distributions of cardiometabolic biomarkers in overweight/obese individuals with DS throughout the lifespan. Descriptive statistics and regression analyses by age categories determined the distributive percentiles for cardiometabolic biomarkers and tested for adiposity as a predictor of CR. Across seven DS clinics, data were collected on 240 patients between the ages of 3 and 63 years, with one quarter overweight and three quarters obese among children and nearly all adults being obese. In children and adults, most cardiometabolic biomarker profiles showed distributive values within normal ranges. Blood lipids were positively associated with body mass index (BMI) in children (high density lipid-cholesterol, p = 0.01; low density lipid-cholesterol, p = 0.02). Levels of hs-CRP were elevated in both children and adults, with BMI positively associated with hs-CRP in adults with DS (p = 0.04). Liver enzyme values were positively associated with BMI in children and adults. The data suggest that in contrast to the general population, in individuals with Down syndrome, being overweight and obese does not appear to confer a significantly increased risk for cardiometabolic disease by biomarker profile. Individuals with DS who are overweight/obese appear to have unique cardiometabolic profiles unrelated to adiposity, notable for increased hs-CRP and normal HA1c levels