Evaluation of Initial and Steady-State Gatifloxacin Pharmacokinetics and Dose in Pulmonary Tuberculosis Patients by Using Monte Carlo Simulations

A 4-month regimen of gatifloxacin with rifampin, isoniazid, and pyrazinamide is being evaluated for the treatment of tuberculosis in a phase 3 randomized controlled trial (OFLOTUB). A prior single-dose study found that gatifloxacin exposure increased by 14% in the combination. The aims of the study are to evaluate the initial and steady-state pharmacokinetics of gatifloxacin when daily doses are given to patients with newly diagnosed drug-sensitive pulmonary tuberculosis as part of a combination regimen and to evaluate the gatifloxacin dose with respect to the probability of attaining a pharmacokinetic/pharmacodynamic target. We describe the population pharmacokinetics of gatifloxacin from the first dose to a median of 28 days in 169 adults enrolled in the OFLOTUB trial in Benin, Guinea, Senegal, and South Africa. The probability of achieving a ratio of ≥125 for the area under the concentration time curve to infinity (AUC_0–∞) for the free fraction of gatifloxacin over the MIC (fAUC/MIC) was investigated using Monte Carlo simulations. The median AUC_0–∞ of 41.2 μg · h/ml decreased on average by 14.3% (90% confidence interval [CI], −90.5% to +61.5%) following multiple 400-mg daily doses. At steady state, 90% of patients achieved an fAUC/MIC of ≥125 only when the MIC was <0.125 μg/ml. We conclude that systemic exposure to gatifloxacin declines with repeated daily 400-mg doses when used together with rifampin, isoniazid, and pyrazinamide, thus compensating for any initial increase in gatifloxacin levels due to a drug interaction. (The OFLOTUB study has been registered at ClinicalTrials.gov under registration no. {"type":"clinical-trial","attrs":{"text":"NCT00216385","term_id":"NCT00216385"}}NCT00216385.)     

Increased expression of protease-activated receptor-2 in mucosal mast cells in Crohn's ileitis

Background and aimsActivation of protease-activated receptor-2 (PAR-2) may stimulate various events of importance in inflammatory processes, including release of inflammatory mast cell mediators. PAR-2 is frequently up-regulated during inflammatory conditions, but it is not known if the expression is altered in Crohn's disease. The aim of the present study was to investigate the ileal mucosal PAR-2 expression in Crohn's ileitis, with particular emphasis on the expression in ileal mucosal mast cells.MethodsSurgical specimens from the distal ileum were collected from patients with Crohn's ileitis and patients with colonic cancer as controls. The overall expression of PAR-2 was investigated by Western blot, and the presence of PAR-2 expressing mucosal mast cells by immunohistochemistry and cell counting. The effect of tumor necrosis factor-α (TNF-α) on the PAR-2 expression in a human mast cell line (HMC-1) was investigated by RT-PCR and immunocytochemistry.ResultsIn Crohn's specimens, the fraction of PAR-2-expressing mucosal mast cells was increased about 2.5 times (P < 0.001; n = 14) compared with specimens from control patients (n = 6). No difference was found between inflamed (n = 6) and uninflamed Crohn's specimens (P > 0.05; n = 8). Exposure to TNF-α for 48 h up-regulated PAR-2 mRNA and protein expression in the HMC-1 cell line.ConclusionPAR-2 is up-regulated on ileal mucosal mast cells in Crohn's ileitis, possibly due to the action of inflammatory cytokines, such as TNF-α. This may contribute to perpetuating the inflammatory process in the intestinal mucosa in Crohn's ileitis.     

Evidence for increased dorsal hippocampal adenosine release and metabolism during pharmacologically induced seizures in rats

There is growing pharmacological evidence from several animal models of seizure disorder that adenosine possesses endogenous anticonvulsant activity. In order to further evaluate the role of adenosine in seizure activity, we monitored adenosine and its major biochemical metabolites inosine, xanthine, and hypoxanthine in the dorsal hippocampus by in vivo microdialysis before and during the induction of generalized seizures. Seizures were induced pharmacologically in groups of urethane-anesthetized rats by the administration of bicuculline (0.5 mg/kg, i.v.), kainic acid (12.0 mg/kg, i.v.) or pentylenetetrazol (100–250 mg/kg, i.p). Seizure activity was monitored electrophysiologically from the dorsal hippocampus. Dialysate hippocampal purine levels increased during all three seizure types. The largest increases were for the adenosine metabolites hypoxanthine and inosine, with smaller increases observed for adenosine and xanthine. Intra-hippocampal perfusion with the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl-adenine, (EHNA, 300 μM), only slightly increased basal hippocampal adenosine. Guanosine levels in the hippocampus, a purine not directly related to adenosine metabolism, were unaffected by all treatments. These findings demonstrate that an increase in hippocampal adenosine release and metabolism is associated with seizure activity and support the hypothesis that the increased adenosine levels may attenuate hippocampal seizure activity, possibly by terminating ongoing seizures and altering the pattern of subsequent seizures.     

When to wash walls in ward rooms?

Surface contamination with Staphylococcus aureus on walls and floors of occupied rooms in an orthopaedic ward, an infectious disease unit, and a burns unit were studied. It was found that walls and floors in the burns unit carried large numbers of bacteria, 10–100 times higher than those in the other units. This may indicate a requirement for routine disinfection of walls and floors in the burns unit but not usually in other wards.     

Activity profiling of deubiquitinating enzymes in cervical carcinoma biopsies and cell lines

Ubiquitin specific proteases (USPs) regulate the production and recycling of ubiquitin and are thereby critically involved in the control of cell growth, differentiation, and apoptosis. Increasing evidence implicates deregulation of USPs in malignant transformation but there is very little information on the overall and specific activity of USPs in normal and tumor tissues. We have used a chemistry-based functional proteomics approach to profile the activities of individual USPs in biopsies of human papillomavirus (HPV) carrying cervical carcinoma and adjacent normal tissue. To assess the contribution of HPV proteins, USP activity was also compared in HPV positive and negative cervical carcinoma cell lines and HPV E6/E7 immortalized human keratinocytes. The activity of the C-terminal hydrolases UCH-L3 and UCH37 was upregulated in the majority of tumor tissues compared to the adjacent normal tissues. UCH-L1 activity was lower in a significant proportion of the tumors but to a less extent in advanced tumors. In accordance with the relatively low UCH-L1 activity in tumor biopsies, UCH-L1 was detected only in one out of eight cervical carcinoma lines. UCH-L1, UCH-L3, USP7, and USP9X activity was upregulated following HPV E6/E7 immortalization of keratinocytes, suggesting a role of these enzymes in growth transformation.     

Retinal Function in Rabbits Does Not Improve 4–5 Months after Terminating Treatment with Vigabatrin

Purpose: We have previously reported changes in retinal function and histopathology in rabbits treated with vigabatrin. The purpose of the present study was to evaluate retinal function and histopathology of retina in rabbits 4–5 months after terminating vigabatrin medication. Methods: Five rabbits were treated with a daily per oral dose of vigabatrin during 12–13 months. After terminating treatment an observation period of 4–5 months followed. Six rabbits receiving water served as controls. Standardized full-field electroretinograms were performed every 6–8 weeks, using a Burian–Allen bipolar contact lens. After 18 months the rabbits were sacrificed and the morphology of the sectioned retina was studied. The antibodies used for staining were GABA, GFAP, GAD, and vimentin. Results: After 12–13 months of treatment the full-field ERG was reduced in all rabbits treated with vigabatrin. There was a statistically significant difference in the dark adapted cone b-wave amplitude between treated animals and controls (Wilcoxon signed-rank test, p = 0.043). This difference was consistent also 4–5 months after terminating treatment. Immunohistology of the sectioned retina demonstrated no significant difference in immunoreactivity between treated animals and controls. All treated rabbits demonstrated elevated serum concentration of the drug during medication. Conclusion: Four to five months after terminating treatment with vigabatrin the rabbit full-field ERG remains reduced in isolated cone b-wave amplitude indicating that vigabatrin induced retinal dysfunction may be irreversible. However, immunohistology is normal after a period without treatment, implying that the previously described changes in retinal morphology and glial cell activity are reversible, and probably exist only during treatment.     

Instrumental strategy: A stage in students' consultation skills training? Observations and reflections on students' communication in general practice consultations

OBJECTIVES: To explore and examine students' abilities to communicate with patients during a general practice course in the final year of the curriculum and to analyse and consider this experience in relation to earlier consultation training. SETTING: General practice courses in the undergraduate curriculum. DESIGN: Qualitative data analysis was used. A special focus-group interview of experienced supervisors was performed and analysed (editing analysis). Credibility of data was tested at local seminars and conferences. Authors' experiences of observing student consultations over many years were also used. RESULTS: A main theme, 'open invitation', emerged based on categories 'initially attentive' and 'listening attitude'. In contrast, the second main theme was 'instrumental strategy', based on the following categories: 'one-sided collection of medical facts' and 'relationship-building lost'. The students also had difficulties in devoting attention to patients' life experiences. An hourglass metaphor of students' and young physicians' progression of communication strategies is presented. The narrow part of the hourglass corresponds to an instrumental strategy at the end of undergraduate clinical education. CONCLUSIONS: An instrumental strategy may be a stage in student's consultation learning progression that interferes with communication training. A question is raised: is training of a patient-centred approach throughout the clinical curriculum needed for optimal development of consultation skills? Further research is needed to test this hypothesis.     

Tetrahydrobiopterin in the treatment of children with autistic disorder: a double-blind placebo-controlled crossover study

Twelve children, all boys, aged 4 to 7 years, with a diagnosis of autistic disorder and low concentrations of spinal 6R-l-erythro-5,6,7,8-tetrahydrobiopterin (tetrahydrobiopterin) were selected to participate in a double-blind, randomized, placebo-controlled, crossover study. The children received a daily dose of 3 mg tetrahydrobiopterin per kilogram during 6 months alternating with placebo. Treatment-induced effects were assessed with the Childhood Autism Rating Scale every third month. The results showed small nonsignificant changes in the total scores of Childhood Autism Rating Scale after 3- and 6-month treatment. Post hoc analysis looking at the 3 core symptoms of autism, that is, social interaction, communication, and stereotyped behaviors, revealed a significant improvement of the social interaction score after 6 months of active treatment. In addition, a high positive correlation was found between response of the social interaction score and IQ. The results indicate a possible effect of tetrahydrobiopterin treatment.