Dirofilariasis mouse models for heartworm preclinical research

Introduction

Dirofilariasis, including heartworm disease, is a major emergent veterinary parasitic infection and a human zoonosis. Currently, experimental infections of cats and dogs are used in veterinary heartworm preclinical drug research.

Methods

As a refined alternative in vivo heartworm preventative drug screen, we assessed lymphopenic mouse strains with ablation of the interleukin-2/7 common gamma chain (γc) as susceptible to the larval development phase of Dirofilaria immitis.

Results

Non-obese diabetic (NOD) severe combined immunodeficiency (SCID)γc^-/- (NSG and NXG) and recombination-activating gene (RAG)2^-/-γc^-/- mouse strains yielded viable D. immitis larvae at 2-4 weeks post-infection, including the use of different batches of D. immitis infectious larvae, different D. immitis isolates, and at different laboratories. Mice did not display any clinical signs associated with infection for up to 4 weeks. Developing larvae were found in subcutaneous and muscle fascia tissues, which is the natural site of this stage of heartworm in dogs. Compared with in vitro-propagated larvae at day 14, in vivo-derived larvae had completed the L4 molt, were significantly larger, and contained expanded Wolbachia endobacteria titres. We established an ex vivo L4 paralytic screening system whereby assays with moxidectin or levamisole highlighted discrepancies in relative drug sensitivities in comparison with in vitro-reared L4 D. immitis. We demonstrated effective depletion of Wolbachia by 70%-90% in D. immitis L4 following 2- to 7-day oral in vivo exposures of NSG- or NXG-infected mice with doxycycline or the rapid-acting investigational drug, AWZ1066S. We validated NSG and NXG D. immitis mouse models as a filaricide screen by in vivo treatments with single injections of moxidectin, which mediated a 60%-88% reduction in L4 larvae at 14-28 days.

Discussion

Future adoption of these mouse models will benefit end-user laboratories conducting research and development of novel heartworm preventatives via increased access, rapid turnaround, and reduced costs and may simultaneously decrease the need for experimental cat or dog use.

1670 The 50 Most Cited Manuscripts in Paediatric Robotic Surgery: A Bibliometric Analysis

Introduction

Robotic assisted surgery is increasingly utilised in paediatric surgery. The purpose of this study was to establish a ranking of the 50 most frequently cited articles addressing this subject and analyse their bibliometric characteristics.

Method

Articles related to paediatric robotic surgery were searched in The Web of Science citation indexing database utilising defined search terms. Results were filtered to include only English language and full manuscripts. The dataset was then ranked by the absolute number of citations and analysed by the journal of publication, impact factor of the journal, title of publication, article type, year of publication, first and senior author, geographic origin, and level of evidence.

Results

The search yielded a total of 352 papers which were ranked in order of citations. The 50 highest cited articles had 2669 citations cumulatively. The most cited article by Lee, RS et al had a citation count of 207. The publication years spanned from 2002 to 2018. 2013 saw the greatest number of publications on this topic. Most articles were of the ‘’Clinical science’’ type. Geographically the USA accounted for most of these publications. All published articles demonstrated a high level of evidence.

Conclusions

The 50 articles identified in this study are clearly influential in this new and evolving field of surgery. Identification of these seminal papers is intended to assist clinicians and scientists in formulating an overview of current and developing trends in this cutting-edge discipline as well as providing a foundational basis for further discussion and future research.

960 Is the Increase in Laparoscopy Leaving Medical Students Behind?

Introduction

Laparoscopy use is exponentially increasing, rapidly becoming the gold standard for many procedures. It is technically demanding, requiring specialised training which is not accessible in early medical education. Studies have shown that interest can be stimulated by experiential learning. Our study evaluates current medical students’ interest and exposure to laparoscopy.

Method

Multiple-choice questionnaires were sent to London medical students assessing their interest and exposure to laparoscopic training in medical school.

Results

231 medical students (86 pre-clinical, 145 clinical students) participated. 174 (75.3%) students reported receiving no laparoscopic training during their medical education. 32 (13.9%) students reported less than one hour of training, 21 (9.1%) students reported two to three hours of training, and 4 (1.7%) students reported receiving three to ten hours of training. 100% of students were interested in receiving further laparoscopic simulation training.

Conclusions

There is insufficient training and exposure of laparoscopy during medical school. The majority of current medical students receive minimal exposure to laparoscopy, despite wanting further training. Teaching basic laparoscopic skills to medical students may provide a feasible option of engaging students in laparoscopy.

An Adaptive Search Algorithm for Detecting Respiratory Artifacts Using a Wireless Passive Wearable Device

With the use of a wireless, wearable, passive knitted smart fabric device as a strain gauge sensor, the proposed algorithm can estimate biomedical feedback such as respiratory activity. Variations in physical properties of Radio Frequency Identification (RFID) signals can be used to wirelessly detect physiological processes and states. However, it is typical for ambient noise artifacts to appear in the RFID signal making it difficult to identify physiological processes. This paper introduces a new technique for finding these repetitive physiological signals and identifying them into two states, active and inactive, using k-means clustering. The algorithm detects these biomedical events without the need to completely remove the noise components using a semi-unsupervised approach, and with these results, predict the next biomedical event using these classification results. This approach enables real-time noninvasive monitoring for use with actuating medical devices for therapy. Using this approach, the algorithm predicts the onset of respiratory activity in a simulated environment within approximately one second.

Genome mining and characterisation of a novel transaminase with remote stereoselectivity

Microbial enzymes from pristine niches can potentially deliver disruptive opportunities in synthetic routes to Active Pharmaceutical Ingredients and intermediates in the Pharmaceutical Industry. Advances in green chemistry technologies and the importance of stereochemical control, further underscores the application of enzyme-based solutions in chemical synthesis. The rich tapestry of microbial diversity in the oceanic ecosystem encodes a capacity for novel biotransformations arising from the chemical complexity of this largely unexplored bioactive reservoir. Here we report a novel ω-transaminase discovered in a marine sponge Pseudovibrio sp. isolate. Remote stereoselection using a transaminase has been demonstrated for the first time using this novel protein. Application to the resolution of an intermediate in the synthesis of sertraline highlights the synthetic potential of this novel biocatalyst discovered through genomic mining. Integrated chemico-genomics revealed a unique substrate profile, while molecular modelling provided structural insights into this ‘first in class’ selectivity at a remote chiral centre.

Medical student attitudes and concepts of frailty and delirium

BACKGROUND

Frailty and delirium are important conditions in an ageing population, but there is little evidence exploring medical students' conceptualisation of, or attitudes towards these subjects. We investigated how students' concepts of frailty and delirium changed following a new geriatric medicine module at Manchester medical school.

MATERIALS AND METHODS

Semi-structured interviews were used with students before and after the new teaching week to explore changes in attitude towards frailty and delirium and their conceptualisation. Final year students who had not completed the module were interviewed as a comparison group. Grounded theory and content clouds were employed for data analysis.

RESULTS

Ten 4th year and 11 final year students were interviewed. After the teaching week, 4th year students had a richer conceptualisation of frailty and delirium. Students described structured assessments such as comprehensive geriatric assessment and expressed confidence in their use. Their frameworks were more developed than the final year students who had not had such teaching. Attitudes towards older people, frailty, delirium, and the specialty of geriatric medicine improved following the teaching week.

CONCLUSION

This study shows that geriatric medicine teaching improves students' conceptualisation of frailty and delirium and their understanding of the importance of structured assessments and management plans.

Comments on potential health effects of MRI-induced DNA lesions: quality is more important to consider than quantity

Magnetic resonance imaging (MRI) is increasingly being used in cardiology to detect heart disease and guide therapy. It is mooted to be a safer alternative to imaging techniques, such as computed tomography (CT) or coronary angiographic imaging. However, there has recently been an increased interest in the potential long-term health risks of MRI, especially in the light of the controversy resulting from a small number of research studies reporting an increase in DNA damage following exposure, with calls to limit its use and avoid unnecessary examination, according to the precautionary principle. Overall the published data are somewhat limited and inconsistent; the ability of MRI to produce DNA lesions has yet to be robustly demonstrated and future experiments should be carefully designed to optimize sensitivity and benchmarked to validate and assess reproducibility. The majority of the current studies have focussed on the initial induction of DNA damage, and this has led to comparisons between the reported induction of γH2AX and implied double-strand break (DSB) yields produced following MRI with induction by imaging techniques using ionizing radiation. However, γH2AX is not only a marker of classical double-ended DSB, but also a marker of stalled replication forks and in certain circumstances stalled DNA transcription. Additionally, ionizing radiation is efficient at producing complex DNA damage, unique to ionizing radiation, with an associated reduction in repairability. Even if the fields associated with MRI are capable of producing DNA damage, the lesions produced will in general be simple, similar to those produced by endogenous processes. It is therefore inappropriate to try and infer cancer risk by simply comparing the yields of γH2AX foci or DNA lesions potentially produced by MRI to those produced by a given exposure of ionizing radiation, which will generally be more biologically effective and have a greater probability of leading to long-term health effects. As a result, it is important to concentrate on more relevant downstream end points (e.g. chromosome aberration production), along with potential mechanisms by which MRI may lead to DNA lesions. This could potentially involve a perturbation in homeostasis of oxidative stress, modifying the background rate of endogenous DNA damage induction. In summary, what the field needs at the moment is more research and less fear mongering.

Stimulation of intercellular induction of apoptosis in transformed cells at very low doses of ionising radiation: spatial and temporal features

The ultimate response of a cell or tissue to radiation is dependent in part on intercellular signalling. This becomes increasingly important at low doses, or at low dose rates, associated with typical human exposures. In order to help characterise the underlying mechanism of intercellular signalling, and how they are perturbed following exposure to ionising radiation, a previously well-defined model system of intercellular induction of apoptosis (IIA) (Portess et al. 2007, Cancer Res. 67, 1246-1253) was adopted. The aim of the present work is to evaluate the signalling mechanisms underpinning this process through exploring the variables that can affect the IIA, i.e. dose, time and space.

Transforming healthcare: a safety imperative

Ten years ago, the Institute of Medicine reported alarming data on the scope and impact of medical errors in the US and called for national efforts to address this problem. While efforts to improve patient safety have proliferated during the past decade, progress toward improvement has been frustratingly slow. Some of this lack of progress may be attributable to the persistence of a medical ethos, institutionalized in the hierarchical structure of academic medicine and healthcare organizations, that discourages teamwork and transparency and undermines the establishment of clear systems of accountability for safe care. The Lucian Leape Institute, established by the US National Patient Safety Foundation to provide vision and strategic direction for the patient safety work, has identified five concepts as fundamental to the endeavor of achieving meaningful improvement in healthcare system safety. These five concepts are transparency, care integration, patient/consumer engagement, restoration of joy and meaning in work, and medical education reform. This paper introduces the five concepts and illustrates the meaning and implications of each as a component of a vision for healthcare safety improvement. In future roundtable sessions, the Institute will further elaborate on the meaning of each concept, identify the challenges to implementation, and issue recommendations for policy makers, organizations, and healthcare professionals.

Iatrogenic tracheal tear

Large post intubation tracheal tears are usually detected intra-operatively due to unstable signs namely impaired ventilation and mediastinal emphysema and often require surgical management. Smaller tracheal tears are often missed during anaesthesia and recognized during the postoperative period. Conservative management should be considered in these latter cases.

Vestibular Rehabilitation in Individuals with Inner-Ear Dysfunction: A Pilot Study

A randomised control prospective study was carried out examining patient outcomes after performing a 10-week vestibular home exercise programme. Thirty-two adults with vestibular dysfunction who reported vestibular symptoms negatively affecting daily life were enrolled. Test subjects were provided with an individualised vestibular rehabilitation programme designed by a physiotherapist. Control subjects received a set of strength and endurance exercises only. All subjects performed their exercises 3 times a day for 10 weeks. Subjective and objective patient measures were collected at 0, 6, 10 and 26 weeks. Results showed that both groups improved after beginning exercise, and that test subjects significantly benefited compared to the controls. These benefits were long term and measurable 6 months later. This study provides evidence that individualised vestibular exercises promote better outcomes for patients with vestibular dysfunction.

Ethical issues in field research: balancing competing values

An ethical issue becomes a dilemma when the psychologist is pulled in different directions by competing values. This paper will focus on the conflict between experimental and ethical values inherent in field research. The problem has special significance in community psychology, which gives priority to studying, in natural settings, those affected by social problems. An example is given of research that required observation of family interaction in the homes of convicted child abusers. The case demonstrates that the value of ecological validity often conflicts with the need to protect privacy and obtain uncoerced consent. Other ethical constraints, including the duty to report lawbreaking and to protect the public from harm, may threaten research validity.

Changes in response to spinal cord injury with development: Vascularization, hemorrhage and apoptosis

Chick embryos are capable of functional spinal cord regeneration following crush injury until embryonic day 13. Developmental changes occurring thereafter result in failure to regenerate. Secondary injury mechanisms can result in apoptotic cell death and make a major contribution to cell loss after trauma. We report here that around embryonic day 13 there is a dramatic increase in blood vessel numbers in the spinal cord, and that the extent of hemorrhage in response to injury increases with developmental age. This is paralleled by increased apoptosis and subsequent cavitation in spinal cords injured at embryonic day 15 as compared with embryonic day 11. Following spinal cord injury at embryonic day 15, apoptotic cell death is extensive and spreads to the same extent as the hemorrhage. When hemorrhage is reduced by treatment with the hemostatic drug desmopressin the extent of apoptosis and cavity formation in spinal cords injured at embryonic day 15 decreases. Furthermore, manipulations of embryonic day 11 spinal cords that increase hemorrhage also increase apoptosis and result in cavitation in contrast to the effective repair typical of this stage. Altogether these results suggest that cavity formation occurring at developmental stages non-permissive for regeneration is largely due to changes in the extent of apoptosis that are related to vascularization and hemorrhage.

Immunofluorescence detection of clustered gamma-H2AX foci induced by HZE-particle radiation

We studied the spatial and temporal distributions of foci of the phosphorylated form of the histone protein H2AX (gamma-H2AX), which is known to be activated by double-strand breaks after irradiation of human fibroblast cells with high-energy silicon (54 keV/microm) and iron (176 keV/microm) ions. Here we present data obtained with the ion path parallel to a monolayer of human fibroblast cells that leads to gamma-H2AX aggregates in the shape of streaks stretching over several micrometers in an x/y plane, thus enabling the analysis of the fluorescence distributions along the ion trajectories. Qualitative analyses of these distributions provide insights into DNA damage processing kinetics for high charge and energy (HZE) ions, including evidence of increased clustering of DNA damage and slower processing with increasing LET.

From Alcohols to SugarsHow Does the Reactivity of α-Hydroxyalkyl Radicals Change with Structure? A Quantitative Examination by Pulse Radiolysis

Rate constants are reported for the 1-electron reduction of the azo dye Orange II in water (pH 7.0) by 10 different alpha-hydroxy radicals. The radicals were created by pulse radiolysis of aqueous solutions of the corresponding alcohol/sugar. The rate constants varied from 1 x 10(8) to 2.7 x 10(9) mol(-1) dm(3) s(-1) and radicals with beta-hydroxy groups had the lowest rate constant. The reaction was found to be controlled by the reduction potentials of the radicals, with steric influences having little effects. Good fits of the data were obtained using the Marcus equation with lambda =140 kJ/mol.

Copasetic analysis: a framework for the blind analysis of microarray imagery

From its conception, bioinformatics has been a multidisciplinary field which blends domain expert knowledge with new and existing processing techniques, all of which are focused on a common goal. Typically, these techniques have focused on the direct analysis of raw microarray image data. Unfortunately, this fails to utilise the image's full potential and in practice, this results in the lab technician having to guide the analysis algorithms. This paper presents a dynamic framework that aims to automate the process of microarray image analysis using a variety of techniques. An overview of the entire framework process is presented, the robustness of which is challenged throughout with a selection of real examples containing varying degrees of noise. The results show the potential of the proposed framework in its ability to determine slide layout accurately and perform analysis without prior structural knowledge. The algorithm achieves approximately, a 1 to 3 dB improved peak signal-to-noise ratio compared to conventional processing techniques like those implemented in GenePix when used by a trained operator. As far as the authors are aware, this is the first time such a comprehensive framework concept has been directly applied to the area of microarray image analysis.