The chinchilla microdialysis model for the study of antibiotic distribution to middle ear fluid

In cases of slow or limited penetration of an antibiotic to the site of infection such as in acute otitis media (the middle ear), plasma levels of the agent may not reflect the concentrations that are relevant in determining clinical outcome. There is a need for a model that allows prediction of the time-course of unbound, pharmacologically active drug levels in middle ear fluid (MEF). This article introduces microdialysis as a sampling tool to measure unbound antibiotic concentrations in the MEF of the chinchilla, and briefly summarizes the results of studies of MEF penetration of a cephalosporin, a macrolide, and a ketolide antibiotic using this technique. The general concurrence of preliminary results of the chinchilla studies with clinical findings suggests that the chinchilla microdialysis model may be useful in predicting efficacy in patients

AAPS-FDA workshop white paper: Microdialysis principles, application and regulatory perspectives

Many decisions in drug development and medical practice are based on measuring blood concentrations of endogenous and exogenous molecules. Yet most biochemical and pharmacological events take place in the tissues. Also, most drugs with few notable exceptions exert their effects not within the bloodstream, but in defined target tissues into which drugs have to distribute from the central compartment. Assessing tissue drug chemistry has, thus, for long been viewed as a more rational way to provide clinically meaningful data rather than gaining information from blood samples. More specifically, it is often the extracellular (interstitial) tissue space that is most closely related to the site of action (biophase) of the drug. Currently microdialysis (mu D) is the only tool available that explicitly provides data on the extracellular space. Although mu D as a preclinical and clinical tool has been available for two decades, there is still uncertainty about the use of mu D in drug research and development, both from a methodological and a regulatory point of view. In an attempt to reduce this uncertainty and to provide an overview of the principles and applications of mu D in preclinical and clinical settings, an AAPS-FDA workshop took place in November 2005 in Nashville, TN, USA. Stakeholders from academia, industry and regulatory agencies presented their views on mu D as a tool in drug research and development

A Comparison of Functional Outcome in Patients Sustaining Major Trauma: A Multicentre, Prospective, International Study

Objectives To compare 6 month and 12 month health status and functional outcomes between regional major trauma registries in Hong Kong and Victoria, Australia. Summary Background Data Multicentres from trauma registries in Hong Kong and the Victorian State Trauma Registry (VSTR). Methods Multicentre, prospective cohort study. Major trauma patients and aged ≥18 years were included. The main outcome measures were Extended Glasgow Outcome Scale (GOSE) functional outcome and risk-adjusted Short-Form 12 (SF-12) health status at 6 and 12 months after injury. Results 261 cases from Hong Kong and 1955 cases from VSTR were included. Adjusting for age, sex, ISS, comorbid status, injury mechanism and GCS group, the odds of a better functional outcome for Hong Kong patients relative to Victorian patients at six months was 0.88 (95% CI: 0.66, 1.17), and at 12 months was 0.83 (95% CI: 0.60, 1.12). Adjusting for age, gender, ISS, GCS, injury mechanism and comorbid status, Hong Kong patients demonstrated comparable mean PCS-12 scores at 6-months (adjusted mean difference: 1.2, 95% CI: −1.2, 3.6) and 12-months (adjusted mean difference: −0.4, 95% CI: −3.2, 2.4) compared to Victorian patients. Keeping age, gender, ISS, GCS, injury mechanism and comorbid status, there was no difference in the MCS-12 scores of Hong Kong patients compared to Victorian patients at 6-months (adjusted mean difference: 0.4, 95% CI: −2.1, 2.8) or 12-months (adjusted mean difference: 1.8, 95% CI: −0.8, 4.5). Conclusion The unadjusted analyses showed better outcomes for Victorian cases compared to Hong Kong but after adjusting for key confounders, there was no difference in 6-month or 12-month functional outcomes between the jurisdictions

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field