Pharmacokinetics of levosimendan and its active metabolite OR-1896 in rapid and slow acetylators.

OBJECTIVE: The purpose of this study was to investigate the pharmacokinetics of levosimendan and to determine the primary pharmacokinetic parameters of the pharmacologically active metabolite OR-1896 in rapid and slow acetylators. METHODS: Levosimendan was administered as a constant rate (0.1 microg/(kg min)) i.v. infusion for 24h in six rapid and six slow acetylators based on N-acetyltransferase 2 genotyping. At the end of the infusion, a small amount (2.5 microg/kg) of (13)C-labeled OR-1896 was administered by i.v. infusion for 10 min. Blood samples were taken at predefined sampling points 14 days post-infusion and levosimendan and its metabolite concentrations were determined by LC-MS/MS. RESULTS: Steady-state concentrations of levosimendan were achieved within 4-8h and no differences were found in the pharmacokinetics of the parent compound between the rapid and slow acetylators. The maximum concentrations of amino phenylpyridazinone metabolite OR-1855 and N-acetylated conjugate OR-1896 were observed approximately 24h after terminating the infusion. AUC of OR-1896 was approximately 3.5 times higher in the rapid acetylators compared to the slow acetylators (P = 0.002, 95% confidence interval for group ratio from 2.0 to 8.2). The mean +/- S.D. fraction of levosimendan metabolized to OR-1896 was 6.8 +/- 2.8% in the rapid and 4.3 +/- 2.4% in the slow acetylators (P = 0.12). (13)C-OR-1855 concentrations were detected in plasma after administration of (13)C-OR-1896 indicating deacetylation from OR-1896 to OR-1855. CONCLUSIONS: Plasma OR-1896 levels during and after levosimendan treatment are dependent on the acetylation status of the subject-rapid acetylators having 3.5 times higher concentrations than slow acetylators.     

Improving safety of gene therapy

Gene therapy has progressed from early clinical trials to first commercial gene therapy drugs. While there is a long history with the side-effects and adverse effects of pharmaceutical drugs, drugs based on gene delivery have presented new challenges for researchers, clinicians and regulatory authorities. On the path from early pre-clinical research to final commercial products, gene therapy tools and production methods have undergone tremendous changes to improve safety and efficacy. Deletion of adenovirus replication genes E1 and E3 has progressed to gutless adenoviruses with all viral genes removed; similarly evolution of lentiviral vectors has progressed from first generation viruses to safer third generation self-inactivating vectors. Improved chromatographic methods have eased the purification of viruses and delivery reservoirs, such as collagen or silicon collars for cardiovascular gene transfer have decreased systemic leakage of viruses; together with tissue-specific promoters and imaging of the biodistribution of viral particles, gene therapy specificity and safety can be improved even further. This review will introduce gene delivery vectors used in gene therapy and highlight key approaches used to improve their safety.     

Head and neck squamous carcinomas with exophytic and endophytic type of growth have the same prognosis after surgery and adjuvant radiotherapy

Head and neck squamous cell carcinomas (HNSCC) are characterized by exophytic or endophytic growth. We hypothesized that the growth pattern predicts outcome and associates with distinct clinical and immunological profiles. Tumors obtained from 60 HNSCC patients treated with surgery and adjuvant radiotherapy were identified as exophytic or endophytic. Recurrence-free survival (RFS) at 42 months was determined. In a subsets of 30 patients (22 exophytic and 8 endophytic) tumor stroma and parenchyma were evaluated for infiltrating CD4⁺ and CD8⁺ T, dendritic, myeloid and FOXP3⁺ regulatory T cells (Treg) and expression of immunosuppressive cytokines by immunohistochemistry. The localization and frequency of positive cells were determined microscopically and analyzed by hierarchical clustering to distinguish exophytic versus endophytic tumors. 34/60 patients had exophytic and 26/60 endophytic tumors. No differences in clinicopathologic data, disease progression or RFS were seen between the two cohorts. Infiltrates of CD3⁺CD8⁺ T cells were larger in endophytic than exophytic tumors, while FOXP3⁺ Treg, TGF-β⁺, IL-10⁺, Arg-1⁺, CD11b⁺ cells were equally prominent in both. FOXP3⁺ Treg accumulated in endophytic tumor nests, while the exophytic tumor stroma was enriched in IL-10⁺ cells (both at p < 0.05). Hierarchical clustering based on immunophenotyping failed to identify different clusters in these two tumor types. However, CD68⁺ macrophages and FOXP3⁺ Treg showed a distinct distribution. The HNSCC growth pattern did not predict RFS. Although higher numbers and differences in localization of immunosuppressive cells in endophytic versus exophytic tumors were observed, no significant relationship was established between the growth pattern and the immune profile of infiltrating lymphocytes.     

Calpain inhibition but not reticulum endoplasmic stress preconditioning protects rat kidneys from p-aminophenol toxicity.

p-Aminophenol (pAP, 225 mg/kg) administration to rats induced renal failure and has been associated with markers of endoplasmic reticulum (ER) stress, as well as calpain and caspase-12 activation in kidneys. To determine the importance of ER stress and calpain during pAP-induced nephrotoxicity, rats were pretreated with low, nontoxic, doses of ER stress inducers or with the selective calpain inhibitor PD150606 (3 mg/kg). Prior ER stress induced by tunicamycin and oxidized dithiothreitol did not result in protection against renal failure, but PD150606 administration was protective and decreased significantly the rise in creatinine and blood urea nitrogen observed after 24-h post-pAP administration. pAP-induced XBP1 upregulation was not modified by calpain inhibition, but a trend to lower GRP94 induction was determined, suggesting that pAP-induced ER stress was mostly calpain independent. In contrast, pAP-induced caspase-12 cleavage products were significantly decreased with PD150606 pretreatment, demonstrating that caspase-12 activation was calpain dependent. This study reveals the importance of calpain in pAP-induced renal failure. Further research with other nephrotoxicants needs to be performed to determine if calpain activation is a common feature of drug-induced renal failure.     

The impact of geographic unit of analysis on socioeconomic inequalities in cancer survival and distant summary stage – a population‐based study

Objective: When using area‐level disadvantage measures, size of geographic unit can have major effects on recorded socioeconomic cancer disparities. This study examined the extent of changes in recorded socioeconomic inequalities in cancer survival and distant stage when the measure of socioeconomic disadvantage was based on smaller Census Collection Districts (CDs) instead of Statistical Local Areas (SLAs). Methods: Population‐based New South Wales Cancer Registry data were used to identify cases diagnosed with primary invasive cancer in 2000–2008 (n=264,236). Logistic regression and competing risk regression modelling were performed to examine socioeconomic differences in odds of distant stage and hazard of cancer death for all sites combined and separately for breast, prostate, colorectal and lung cancers. Results: For all sites collectively, associations between socioeconomic disadvantage and cancer survival and distant stage were stronger when the CD‐based socioeconomic disadvantage measure was used compared with the SLA‐based measure. The CD‐based measure showed a more consistent socioeconomic gradient with a linear upward trend of risk of cancer death/distant stage with increasing socioeconomic disadvantage. Site‐specific analyses provided similar findings for the risk of death but less consistent results for the likelihood of distant stage. Conclusions: The use of socioeconomic disadvantage measure based on the smallest available spatial unit should be encouraged in the future. Implications for public health: Disadvantage measures based on small spatial units can more accurately identify socioeconomic cancer disparities to inform priority settings in service planning.     

Percutaneous drainage of tuberculous iliopsoas abscesses under image guidance

Most intra-abdominal and other types of fluid collections are now successfully drained percutaneously under image guidance. The utility of percutaneous drainage of tuberculous abscesses, especially those associated with osseous changes, is, however, less well established. Six patients with tuberculous iliopsoas abscesses were successfully managed by percutaneous drainage combined with antituberculous therapy. The abscesses were bilateral in one patient and unilateral in the other five. Drainage was by needle aspiration under ultrasound (US) guidance in one patient, and by catheter under CT guidance in the other patients. Three patients had associated osseous changes. There were no procedural complications. Tuberculous iliopsoas abscess can be successfully treated by percutaneous drainage and appropriate antituberculous therapy.