Calcium imaging in freely-moving mice during electrical stimulation of deep brain structures.

After decades of study in humans and animal models, there remains a lack of consensus regarding how the action of electrical stimulation on neuronal and non-neuronal elements - e.g. neuropil, cell bodies, glial cells, etc. - leads to the therapeutic effects of neuromodulation therapies. To further our understanding of neuromodulation therapies, there is a critical need for novel methodological approaches using state-of-the-art neuroscience tools to study neuromodulation therapy in preclinical models of disease. In this manuscript we outline one such approach combining chronic behaving single-photon microendoscope recordings in a pathological mouse model with electrical stimulation of a common deep brain stimulation (DBS) target. We describe in detail the steps necessary to realize this approach, as well as discuss key considerations for extending this experimental paradigm to other DBS targets for different therapeutic indications. Additionally, we make recommendations from our experience on implementing and validating the required combination of procedures that includes: the induction of a pathological model (6-OHDA model of Parkinson's disease) through an injection procedure, the injection of the viral vector to induce GCaMP expression, the implantation of the GRIN lens and stimulation electrode, and the installation of a baseplate for mounting the microendoscope. We proactively identify unique data analysis confounds occurring due to the combination of electrical stimulation and optical recordings and outline an approach to address these confounds. In order to validate the technical feasibility of this unique combination of experimental methods, we present data to demonstrate that 1) despite the complex multifaceted surgical procedures, chronic optical recordings of hundreds of cells combined with stimulation is achievable over week long periods 2) this approach enables measurement of differences in DBS evoked neural activity between anesthetized and awake conditions and 3) this combination of techniques can be used to measure electrical stimulation induced changes in neural activity during behavior in a pathological mouse model. These findings are presented to underscore the feasibility and potential utility of minimally constrained optical recordings to elucidate the mechanisms of DBS therapies in animal models of disease.

Rebleeding and Mortality After Lower Gastrointestinal Bleeding in Patients Taking Antiplatelets or Anticoagulants.

BACKGROUND & AIMS: Patients who develop lower gastrointestinal bleeding (LGIB) while receiving anticoagulants or anti-platelets have increased severity of bleeding and risk of rebleeding. We compared outcomes of patients receiving antiplatelets, anticoagulants, or direct oral anticoagulants (DOACs) who develop LGIB, as well as the effects of withholding these drugs on their course of bleeding. METHODS: We performed a retrospective study of 2528 consecutive adult patients with LGIB at 143 hospitals in the United Kingdom, from September through December 2015; 917 were taking anticoagulant or antiplatelet drugs and 1218 were taking neither (unexposed). We collected data on demographic features of patients, interventions or medications, outcomes, laboratory test results, and patient readmission until patient death, discharge, or 28 days after admission (whichever came first). Rebleeding was defined as additional transfusion requirements and/or a decrease in hematocrit ≥20% after 24 hrs of clinical stability. Multivariate regression was used to examine the relationship between drug class on presentation with LGIB and rebleeding, mortality, and cardiovascular events. Rates of rebleeding and cardiovascular complications in patients who had these drugs withheld were also analyzed. RESULTS: Patients receiving antiplatelets, but not those receiving warfarin (n = 232) or DOACs (n = 102), had a higher risk of in-hospital rebleeding (monotherapy hazard ratio [HR], 3.57; 95% CI, 1.13-11.28; n = 504 and dual antiplatelet therapy hazard ratio, 5.3; 95% CI, 1.56-18.54; n = 79) compared with the unexposed group. This risk was not lower in patients who received antiplatelets and had the drug withheld for fewer than 5 days, compared to those who continued the drug throughout admission (HR, 0.98; 95% CI, 0.45-2.17) No differences were observed in risk-adjusted mortality or readmission with further bleeding for patients receiving antiplatelets, DOACs, or warfarin. Cardiovascular events were too few to allow meaningful comparison. CONCLUSIONS: In patients with LGIB, antiplatelet drugs, but not warfarin or DOACs, are associated with an increased risk of rebleeding. Withholding antiplatelets during admission does not lead to reduction in rebleeding.

Simultaneous Optogenetics and Cellular Resolution Calcium Imaging During Active Behavior Using a Miniaturized Microscope.

The ability to precisely monitor and manipulate neural circuits is essential to understand the brain. Advancements over the last decade in optical techniques such as calcium imaging and optogenetics have empowered researchers to gain insight into brain function by systematically manipulating or monitoring defined neural circuits. Combining these cutting-edge techniques enables a more direct mechanism for ascribing neural dynamics to behavior. Here, we developed a miniaturized integrated microscope that allows for simultaneous optogenetic manipulation and cellular-resolution calcium imaging within the same field of view in freely behaving mice. The integrated microscope has two LEDs, one filtered with a 435-460 nm excitation filter for imaging green calcium indicators, and a second LED filtered with a 590-650 nm excitation filter for optogenetic modulation of red-shifted opsins. We developed and tested this technology to minimize biological and optical crosstalk. We observed insignificant amounts of biological and optical crosstalk with regards to the optogenetic LED affecting calcium imaging. We observed some amounts of residual crosstalk of the imaging light on optogenetic manipulation. Despite residual crosstalk, we have demonstrated the utility of this technology by probing the causal relationship between basolateral amygdala (BLA) -to- nucleus accumbens (NAc) circuit function, behavior, and network dynamics. Using this integrated microscope we were able to observe both a significant behavioral and cellular calcium response of the optogenetic modulation on the BLA-to-NAc circuit. This integrated strategy will allow for routine investigation of the causality of circuit manipulation on cellular-resolution network dynamics and behavior.

Testing a trigger tool as a method of detecting harm from medication errors in a UK hospital: a pilot study.

OBJECTIVES: The aim was to adapt a US adverse drug event (ADE) trigger tool for UK use, and to establish its positive predictive value (PPV) and sensitivity in comparison to retrospective health record review for the identification of preventable ADEs, in a pilot study on one hospital ward. METHODS: An established US trigger tool was adapted for UK use. We applied it retrospectively to 207 patients' health records, following up positive triggers to identify any ADEs (both preventable and non-preventable). We compared the preventable ADEs to those identified using full health record review. KEY FINDINGS: We identified 168 positive triggers in 127 (61%) of 207 patients. Seven ADEs were identified, representing an ADE in 3.4% of patients or 0.7 ADEs per 100 patient days. Five were non-preventable adverse drug reactions and two were due to preventable errors. The prevalence of preventable ADEs was 1.0% of patients, or 0.2 per 100 patient days. The overall PPV was 0.04 for all ADEs, and 0.01 for preventable ADEs. PPVs for individual triggers varied widely. Five preventable ADEs were identified using health record review. The sensitivity of the trigger tool for identifying preventable ADEs was 0.40, when compared to health record review. CONCLUSIONS: Although we identified some ADEs using the trigger tool, more work is needed to further refine the trigger tool to reduce the false positives and increase sensitivity. To comprehensively identify preventable ADEs, retrospective health record review remains the gold standard and we found no efficiency gain in using the trigger tool.

The incidence of prescribing errors in hospital inpatients: an overview of the research methods.

Many different methods have been used to study the incidence of prescribing errors in hospital inpatients. The objectives of this review were to outline the methods used, highlight their strengths and limitations, and summarise the incidence of prescribing errors reported. Methods used may be retrospective or prospective and based on process or on outcome. Reported prescribing error rates vary widely, ranging from 0.3% to 39.1% of medication orders written and from 1% to 100% of hospital admissions. Unfortunately, there is no standard denominator for use when expressing prescribing error rates. It could be argued that the most meaningful is the number of medication orders written; however, it is also helpful to consider the number of medication orders written per patient stay in order to understand the risk that a given prescribing error rate poses to an individual patient. Because of wide variation in the definitions and methods used, it is difficult to make comparisons between different studies. Each method for identifying prescribing errors has advantages and disadvantages. Process-based studies potentially allow all errors to be identified, giving more scope for the identification of trends and learning opportunities, and it may be easier to collect sufficient data to show statistically significant changes in prescribing error rates following interventions to reduce them. However, studies based on process may be criticised for focusing on many minor errors that are very unlikely to have resulted in patient harm. Focusing instead on harm, as in outcome-based studies, allows efforts to reduce errors to be targeted on those areas that are likely to result in the highest impact. Therefore, the most appropriate method depends on the study's aims. However, using a combination of methods is likely to be the most useful approach if comprehensive data are required.

Causes of prescribing errors in hospital inpatients: a prospective study.

BACKGROUND: To prevent errors made during the prescription of drugs, we need to know why they arise. Theories of human error used to understand the causes of mistakes made in high-risk industries are being used in health-care. They have not, however, been applied to prescribing errors, which are a great cause of patient harm. Our aim was to use this approach to investigate the causes of such errors. METHODS: Pharmacists at a UK teaching hospital prospectively identified 88 potentially serious prescribing errors. We interviewed the prescribers who made 44 of these, and analysed our findings with human error theory. FINDINGS: Our results suggest that most mistakes were made because of slips in attention, or because prescribers did not apply relevant rules. Doctors identified many risk factors-work environment, workload, whether or not they were prescribing for their own patient, communication within their team, physical and mental well-being, and lack of knowledge. Organisational factors were also identified, and included inadequate training, low perceived importance of prescribing, a hierarchical medical team, and an absence of self-awareness of errors. INTERPRETATION: To reduce prescribing errors, hospitals should train junior doctors in the principles of drug dosing before they start prescribing, and enforce good practice in documentation. They should also create a culture in which prescription writing is seen as important, and formally review interventions made by pharmacists, locum arrangements, and the workload of junior doctors, and make doctors aware of situations in which they are likely to commit errors.