Prioritising the prevention of medication handling errors

Objective Medication errors are frequent in a hospital setting and often caused by inappropriate drug handling. Systematic strategies for their prevention however are still lacking. We developed and applied a classification model to categorise medication handling errors and defined the urgency of correction on the basis of these findings. Setting Nurses on medical wards (including intensive and intermediate care units) of a 1,680-bed teaching hospital. Method In a prospective observational study we evaluated the prevalence of 20 predefined medication handling errors on the ward. In a concurrent questionnaire survey, we assessed the knowledge of the nurses on medication handling. The severity of errors observed in individual areas was scored considering prevalence, potential risk of an error, and the involved drug. These scores and the prevalence of corresponding knowledge deficits were used to define the urgency of preventive strategies according to a four-field decision matrix. Main outcome measure Prevalence and potential risk of medication handling errors, corresponding knowledge deficits in nurses committing the errors, and priority of quality improvement. Results In 1,376 observed processes 833 medication handling errors were detected. Errors concerning preparation (mean 0.88 errors per observed process [95% CI: 0.81–0.96], N = 645) were more frequent than administration errors (0.36 [0.32–0.41], N = 701, P < 0.001). Parenteral drugs (1.10 [1.00–1.19], N = 492) were more often involved in errors than enteral drugs (0.32 [0.28–0.36], N = 794, P < 0.001). Of the 833 observed medication errors 30.9% concerned processes of high risk, 19.0% of moderate risk, and 50.1% of low risk. Of these errors 11.4% were caused by critical dose drugs, 81.6% by uncomplicated drugs, and 6.9% by nutritional supplements or diluents without active ingredient. According to the decision matrix that also considered knowledge deficits two error types concerning enteral drugs (flaws in light protection and prescribing information) were given maximum priority for quality improvement. For parenteral drugs five errors (incompatibilities, flaws in hygiene, duration of administration, check for visible abnormalities, and again prescribing information) appeared most important. Conclusion We successfully applied a newly developed classification model to prioritise medication handling errors for prevention strategies.     

Organ-specific response to inhibition of mitochondrial metabolism by cyclosporine in the rat

To evaluate organ-specific metabolic changes after in vivo cyclosporine (CyA) treatment, male Wistar rats were treated with 10 mg/kg per day CyA orally for 6 days. Blood, kidney, liver, and heart tissues were extracted and analyzed by magnetic resonance spectroscopy (MRS). CyA decreased the energy balance [adenosine triphosphate (ATP)/adenosine diphosphate (ADP)] in all organs (kidney [control]: 50%, liver: 64%, and heart: 62%, all P<0.01) due to decreased activity of the mitochondrial Krebs cycle and oxidative phosphorylation. As a compensatory effect, anaerobic glycolysis (lactate) was increased. This was reflected in the low glucose level in the kidney and heart, but not in the liver where a significant decrease in glycogen was seen. Only in the kidney was mitochondrial inhibition accompanied by decreased polyunsaturated fatty acid (PUFA) concentrations and elevated lipid peroxidation. The metabolic marker for nephrotoxicity, trimethylamine-N-oxide (TMAO), was elevated. While CyA decreased mitochondrial homeostasis in all organ systems, cellular adaptation was different and most efficient in the liver.The results of this study were presented in part at the 2002 Winter Symposium of the American Society of Transplant Surgeons, Miami, 25–27 January 2002     

Targeting CLA/E-selectin interactions prevents CCR4-mediated recruitment of human Th2 memory cells to human skin in vivo

Naive Th cells, bearing receptors for cutaneous antigens, become activated in skin-draining lymph nodes and express cutaneous lymphocyte antigen (CLA), which confers to these cells the capacity to migrate into the skin to exert their normal effector functions. In the case of atopic dermatitis (AD), allergen-specific Th2 cells generate exacerbated responses and induce skin inflammation. In such a situation, interfering with the specific mechanism of skin homing would provide a therapeutic benefit. Here we report that CLA+ Th2 memory cells, derived from skin lesions of AD patients, selectively migrate to human skin grafts transplanted onto SCID mice in response to CCR4 but not CCR3, CCR8 or CXCR3 ligands. Skin homing of human CCR4+ Th2 memory cells was Pertussis toxin sensitive and restricted to the CLA+ subset. Furthermore, treatment of these mice with anti-E-selectin monoclonal antibody was sufficient to prevent CCL22-mediated Th2 cell migration to human skin, which both, validates the model and highlights the importance of CLA/E-selectin interactions in the homing process of Th2 cells to the skin. Using this mechanistic model we demonstrate that skin homing of human Th2 memory cells can be efficiently suppressed using a low molecular weight E-selectin antagonist, which is of clinical relevance for the treatment of inflammatory skin diseases, including AD.     

Gene expression profiling of embryo-derived stem cells reveals candidate genes associated with pluripotency and lineage specificity

Large-scale gene expression profiling was performed on embryo-derived stem cell lines to identify molecular signatures of pluripotency and lineage specificity. Analysis of pluripotent embryonic stem (ES) cells, extraembryonic-restricted trophoblast stem (TS) cells, and terminally-differentiated mouse embryo fibroblast (MEF) cells identified expression profiles unique to each cell type, as well as genes common only to ES and TS cells. Whereas most of the MEF-specific genes had been characterized previously, the majority (67%) of the ES-specific genes were novel and did not include known differentiated cell markers. Comparison with microarray data from embryonic material demonstrated that ES-specific genes were underrepresented in all stages sampled, whereas TS-specific genes included known placental markers. Investigation of four novel TS-specific genes showed trophoblast-restricted expression in cell lines and in vivo, whereas one uncharacterized ES-specific gene, Esg-1, was found to be exclusively associated with pluripotency. We suggest that pluripotency requires a set of genes not expressed in other cell types, whereas lineage-restricted stem cells, like TS cells, express genes predictive of their differentiated lineage.     

Association between a polymorphism in the pseudoautosomal X-linked gene SYBL1 and bipolar affective disorder

In the past decade, several chromosomal regions have been analyzed for linkage with bipolar affective disorder (BPAD). There have been conflicting results regarding the involvement of X-chromosomal regions in harboring susceptibility genes for BPAD. Recently, a new candidate gene (SYBL1) for BPAD has been described on Xq28. SYBL1, which maps to the Xq pseudoautosomal region (PAR), encodes a member of the synaptobrevin family of proteins involved in synaptic vesicle docking, exocytosis, and membrane transport. A subsequent case-control association study, including 110 US-American patients with BPAD and 119 unrelated controls, investigated a potential etiological role of a novel polymorphism (G-->C transversion) in a regulatory region of the SYBL1 gene. In this analysis, the C allele showed a statistical trend to be more frequent in males with BPAD than in respective controls (P=0.06). This finding prompted us to verify whether a similar effect was also present in a larger German sample of 164 unrelated patients with BPAD (148 patients with BP I disorder, 16 patients with BP II disorder) and 267 controls. We observed a significantly increased frequency of genotypes homozygous for the C allele in females with BPAD in comparison with controls (P=0.017). Thus, our data strengthen the role of the SYBL1 gene as a candidate gene for BPAD.     

Cyclosporine can increase isoflurane MAC

Previous reports indicate that cyclosporine increases sleeping time from barbiturate administration, and analgesia from fentanyl administration, suggesting a possible contribution of cyclosporine to anesthesia. Accordingly, we determined whether cyclosporine pretreatment decreases isoflurane MAC (the minimum alveolar concentration of anesthetic required to eliminate movement in response to noxious stimulation in 50% of subjects) in rats, and whether cyclosporine changes the hindpaw withdrawal latency (HPWL) test to thermal nociceptive stimulation. We assigned rats to receive vehicle (control; n = 18), 7.5 mg. kg(-1). d(-1) cyclosporine (n = 10), or 15 mg. kg(-1). d(-1) cyclosporine (n = 20). MAC was determined before and immediately after 3 days of treatment. HPWL was determined after 3 days of treatment in controls (vehicle) and cyclosporine (15 mg. kg(-1). d(-1)) treated animals. Cyclosporine 7.5 and 15 mg. kg(-1). d(-1) increased MAC by 10.4% +/- 7.3% and 23.1% +/- 17.1% (mean +/- SD) (P < 0.05), respectively. The changes in isoflurane MAC correlated significantly with cyclosporine blood concentrations. Cyclosporine did not significantly increase HPWL. Contrary to our hypotheses, cyclosporine increases rather than decreases MAC, but does not confer appreciable analgesia. IMPLICATIONS: The immunosuppressive drug, cyclosporine, which is frequently used after organ transplantation, increases the amount of a commonly used anesthetic (isoflurane) necessary to avoid movement to painful stimuli in the rat.     

Mismatch responses to randomized gradient switching noise as reflected by fMRI and whole-head magnetoencephalography

The central auditory system of the human brain uses a variety of mechanisms to analyze auditory scenes, among others, preattentive detection of sudden changes in the sound environment. Electroencephalography (EEG) and magnetoencephalography (MEG) provide a measure to monitor neuronal cortical currents. The mismatch negativity (MMN) or field (MMNm) reflect preattentive activation in response to deviants within a sequence of homogenous auditory stimuli. Functional magnetic resonance imaging (fMRI) allows for a higher spatial resolution as compared to the extracranial electrophysiological techniques. The image encoding gradients of echo planar imaging (EPI) sequences, however, elicit an interfering background noise. To circumvent this shortcoming, the present study applied multi-echo EPI mimicking an auditory oddball design. The gradient trains (SOA = 800 msec, 94.5 dB SPL, stimulus duration = 152 msec) comprised amplitude (-9 dB) and duration (76 msec) deviants in a randomized sequence. Moreover, the scanner noise was recorded and applied in a whole-head MEG device to validate the properties of this specific material. Robust fMRI activation patterns emerged in response to the deviant gradient switching. Changes in amplitude activated the entire auditory cortex, whereas the duration deviants elicited right-lateralized signal increase in secondary areas. The recorded scanner noise evoked reliably right-lateralized mismatch MEG responses. Source localization was in accordance with activation of secondary auditory cortex. The presented paradigm provides a robust and feasible tool to study the functional anatomy of early cognitive auditory processing in clinical populations such as schizophrenia.     

Developmental expression of functional cyclooxygenases in zebrafish

Study of the cyclooxygenases (COXs) has been limited by the role of COX-2 in murine reproduction and renal organogenesis. We sought to characterize COX expression and function in zebrafish (z). Full-length cDNAs of zCOX-1 and zCOX-2 were cloned and assigned to conserved regions of chromosomes 5 and 2, respectively. The deduced proteins are 67% homologous with their human orthologs. Prostaglandin (PG) E(2) is the predominant zCOX product detected by mass spectrometry. Pharmacological inhibitors demonstrate selectivity when directed against heterologously expressed zCOX isoforms. Zebrafish thrombocyte aggregation ex vivo and hemostasis in vivo are sensitive to inhibition of zCOX-1, but not zCOX-2. Both zCOXs were widely expressed during development, and knockdown of zCOX-1 causes growth arrest during early embryogenesis. zCOX-1 is widely evident in the embryonic vasculature, whereas zCOX-2 exhibits a more restricted pattern of expression. Both zCOX isoforms are genetically and functionally homologous to their mammalian orthologs. The zebrafish affords a tractable model system for the study of COX biology and development.