Are postoperative antibiotics required after orthognathic surgery?

The aim of this study was to investigate and compare the frequency of surgical site infection (SSI) between orthognathic patients who received only intraoperative antibiotics and patients who received intraoperative antibiotics plus postoperative antibiotics. A retrospective study was performed of patients treated by a single surgeon over the years 2006-2012 and 2016-2019. The primary predictor variable was antibiotic exposure. The control group received no postoperative prophylactic antibiotics. The study group received postoperative antibiotics. Both groups received prophylactic intraoperative antibiotics and performed postoperative chlorhexidine rinses. The primary outcome was SSI frequency. Univariate, bivariate, and multiple logistic regression analyses were performed; statistical significance was set at P ≤ 0.05. The sample comprised 333 patients. Their mean age was 30.7 ± 11.8 years. The study group included 129 patients (38.7%); the control group included 204 patients (61.3%). The frequency of SSI was 17.1% in the study group and 26.5% in the control group (P = 0.048). In the multivariable logistic regression, only alcohol consumption was significantly associated with an increased risk of SSI (odds ratio 2.46, 95% confidence interval 1.36-4.44; P = 0.003). In patients undergoing orthognathic surgery, postoperative antibiotic exposure in addition to intraoperative prophylaxis approached but was not statistically significant for a decreased risk of SSI (P = 0.067).

309 A FRAILTY CENSUS OF INPATIENTS AGED 65 AND OVER ADMITTED TO A MODEL 4 HOSPITAL

Background

Frailty is a risk factor for in-hospital mortality, long hospital stay and functional decline at discharge. Profiling the prevalence and level of frailty within the acute hospital setting is vital to ensure evidence-based practice and service development within the construct of frailty.

Methods

All patients aged ≥65 years and admitted to a medical or surgical inpatient setting, were screened over a 12-hour period (08:00-20:00) using validated frailty and co-morbidity scales. Age and Gender Demographics, Clinical Frailty Scale (CFS), Charlson Co-morbidity Index (CHI) and admitting specialty (Medical/Surgical) were collected. The data was fully anonymised and ethical approval was granted. Descriptive statistics were used to profile the cohort and Chi-squared tests applied for comparisons.

Results

Within a sample of 413 patients, 291(70%) were ≥65yrs. Of this cohort, 202(70%) were ≥75yrs. 207(71%) utilised in-patient medical services and 121(41%) surgical services while 37(12%) used both. The mean CFS was 6 indicating moderate frailty levels and the mean CCI score was 4 denoting moderate co-morbidity. Overall: 195(67%) had moderate-severe frailty (CSF ≥6) while 218 (75%) had moderate-severe co-morbidity (CCI Mod 3-4, Severe ≥5). Associations with age >75 and frailty (p=0.001) and medical service usage and frailty (p=0.004) were established. No significant differences were observed across genders for CFS (p=0.110) and CCI (p=0.465).

Conclusion

There is a high prevalence of frailty and co-morbidity within the admitted patient cohort ≥65yrs. Overcrowding across the hospital system and higher levels of frailty and comorbidity will contribute to increased lengths of stay and the need for specialist intervention, particularly for those ≥75yrs who represented 70% of patients screened. With an increased focus on the integration of care for older adults across care transitions, there is a clear need for expansion of frailty-based services and staff training in frailty care across the hospital and community setting.

Confounds of using the unc-58 selection marker highlights the importance of genotyping co-CRISPR genes

Multiple advances have been made to increase the efficiency of CRISPR/Cas9 editing using the model genetic organism Caenorhabditis elegans (C. elegans). Here we report on the use of co-CRISPR ‘marker’ genes: worms in which co-CRISPR events have occurred have overt, visible phenotypes which facilitates the selection of worms that harbour CRISPR events in the target gene. Mutation in the co-CRISPR gene is then removed by outcrossing to wild type but this can be challenging if the CRISPR and co-CRISPR gene are hard to segregate. However, segregating away the co-CRISPR modified gene can be less challenging if the worms selected appear wild type and are selected from a jackpot brood. These are broods in which a high proportion of the progeny of a single injected worm display the co-CRISPR phenotype suggesting high CRISPR efficiency. This can deliver worms that harbour the desired mutation in the target gene locus without the co-CRISPR mutation. We have successfully generated a discrete mutation in the C. elegans nlg-1 gene using this method. However, in the process of sequencing to authenticate editing in the nlg-1 gene we discovered genomic rearrangements that arise at the co-CRISPR gene unc-58 that by visual observation were phenotypically silent but nonetheless resulted in a significant reduction in motility scored by thrashing behaviour. This highlights that careful consideration of the hidden consequences of co-CRISPR mediated genetic changes should be taken before downstream analysis of gene function. Given this, we suggest sequencing of co-CRISPR genes following CRISPR procedures that utilise phenotypic selection as part of the pipeline.

Investigating autism associated genes in C. elegans reveals candidates with a role in social behaviour

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterised by a triad of behavioural impairments and includes disruption in social behaviour. ASD has a clear genetic underpinning and hundreds of genes are implicated in its aetiology. However, how single penetrant genes disrupt activity of neural circuits which lead to affected behaviours is only beginning to be understood and less is known about how low penetrant genes interact to disrupt emergent behaviours. Investigations are well served by experimental approaches that allow tractable investigation of the underpinning genetic basis of circuits that control behaviours that operate in the biological domains that are neuro-atypical in autism. The model organism C. elegans provides an experimental platform to investigate the effect of genetic mutations on behavioural outputs including those that impact social biology. Here we use progeny-derived social cues that modulate C. elegans food leaving to assay genetic determinants of social behaviour. We used the SAFRI Gene database to identify C. elegans orthologues of human ASD associated genes. We identified a number of mutants that displayed selective deficits in response to progeny. The genetic determinants of this complex social behaviour highlight the important contribution of synaptopathy and implicates genes within cell signalling, epigenetics and phospholipid metabolism functional domains. The approach overlaps with a growing number of studies that investigate potential molecular determinants of autism in C. elegans. However, our use of a complex, sensory integrative, emergent behaviour provides routes to enrich new or underexplored biology with the identification of novel candidate genes with a definable role in social behaviour.

Neuroligin dependence of social behaviour in Caenorhabditis elegans provides a model to investigate an autism-associated gene

Autism spectrum disorder (ASD) is characterized by a triad of behavioural impairments including social behaviour. Neuroligin, a trans-synaptic adhesion molecule, has emerged as a penetrant genetic determinant of behavioural traits that signature the neuroatypical behaviours of autism. However, the function of neuroligin in social circuitry and the impact of genetic variation to this gene is not fully understood. Indeed, in animal studies designed to model autism, there remains controversy regarding the role of neuroligin dysfunction in the expression of disrupted social behaviours. The model organism, Caenorhabditis elegans, offers an informative experimental platform to investigate the impact of genetic variants on social behaviour. In a number of paradigms, it has been shown that inter-organismal communication by chemical cues regulates C. elegans social behaviour. We utilize this social behaviour to investigate the effect of autism-associated genetic variants within the social domain of the research domain criteria. We have identified neuroligin as an important regulator of social behaviour and segregate the importance of this gene to the recognition and/or processing of social cues. We also use CRISPR/Cas9 to edit an R-C mutation that mimics a highly penetrant human mutation associated with autism. C. elegans carrying this mutation phenocopy the behavioural dysfunction of a C. elegans neuroligin null mutant, thus confirming its significance in the regulation of animal social biology. This highlights that quantitative behaviour and precision genetic intervention can be used to manipulate discrete social circuits of the worm to provide further insight into complex social behaviour.

Early outcome of cardiac surgery in dialysis-dependent end-stage renal failure patients

INTRODUCTION

Preoperative dialysis-dependent renal failure is a strong independent risk factor for in-hospital mortality and morbidity after open heart surgery. This retrospective study analyses the early outcome in dialysis-dependent renal failure patients who underwent elective open-heart surgery in the Institut Jantung Negara (IJN).

METHODS

We retrospectively analyse a series of 228 consecutive postoperative patients with dialysis-dependent (end stage renal failure (ESRF)) admitted to the adult cardiothoracic ICU in IJN between January 2012 and December 2016.

RESULTS

The overall early mortality rate included 34 patients (15.8%). Patients with ESRF underwent combined procedure recorded a very high mortality rate at 56.3%. Twenty-four patients (11.2%) needed resternotomy for postoperative bleeding or cardiac temponade. Postoperative mediastinitis rate was high, involving 13 patients (6%). The neurological and gastrointestinal complications rate were recorded at 2.3% (5 patients) and 6% (13 patients) respectively. In the group of patients (n=199) with sinus rhythm during the preoperative period, 100 patients (50.3%) developed postoperative AF. 77 patients (35.8%) stayed in hospital for more than 14 days.

CONCLUSIONS

dialysis-dependent patients undergoing cardiac surgery poses higher perioperative risk of mortality and morbidity of 3-4 times higher compared to those patients with normal renal function. IJN shows acceptable perioperative risk of mortality and morbidity which is comparable to other centres.

Method Extension Study to Validate Applicability of AOAC Official Method 996.14 Assurance® Polyclonal Enzyme Immunoassay for Detection of Listeria monocytogenes and Related Listeria spp. from Environmental Surfaces: Collaborative Study

Test portions from 3 environmental surface types, representative of typical surfaces found in a food production facility, were analyzed by the Assurance®Listeria Polyclonal Enzyme Immunoassay (EIA) and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) culture method for Listeria monocytogenes and related Listeria species. In all cases, naturally contaminated environmental test samples were collected from an actual food production facility by sponge or swab. Test samples from concrete surfaces were collected by both swab and sponge; sponge test samples were collected from rubber surfaces, and swabs were used to sample steel surfaces. Test portions from each surface type were simultaneously analyzed by both methods. A total of 23 collaborators, representing government agencies, as well as private industry in both the United States and Canada, participated in the study. During this study, a total of 550 test portions and controls was analyzed and confirmed, of which 207 were positive and 336 were negative by both methods. Six test portions were positive by culture, but negative by the EIA. Three test portions were negative by culture, but positive by the EIA. Two test portions were negative by EIA and by culture, but confirmed positive when EIA enrichment broths were subcultured to selective agars. The data reported here indicate that the Assurance®Listeria EIA method and the USDA/FSIS culture method are statistically equivalent for detection of L. monocytogenes and related Listeria species from environmental surfaces taken by sponges or swabs.

Visual Immunoprecipitate Assay Eight Hour Method for Detection of Enterohemorrhagic Escherichia coli O157:H7 in Raw and Cooked Beef (Modification of AOAC Official Method 996.09): Collaborative Study

AOAC Official Method 996.09, Visual Immunoprecipitate Assay (VIP®) for Escherichia coli O157:H7, was modified to incorporate a new enrichment protocol using BioControl EHEC8™ medium for testing raw and cooked beef. Foods were tested by VIP assay and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) enrichment procedure and the FDA Bacteriological Analytical Manual (BAM) isolation and confirmation techniques. A total of 15 collaborators participated. Raw and cooked ground beef were inoculated with E. coli O157:H7 at 2 different levels: a high level, where predominantly positive results were expect d, and a low level where fractional recovery was anticipated. Collaborators tested 396 test portions and controls by both methods, for a total of 792 test portions. Of the 396 paired test portions, 75 were positive and 230 were negative by both the VIP and culture methods. Eleven test portions were presumptively positive by VIP and could not be confirmed culturally; 32 were negative by VIP, but confirmed positive by culture; and 65 were negative by the culture method, but confirmed positive by the VIP method. There was no statistical difference between results obtained with the VIP for EHEC 8 h method and the culture method except for cooked beef, where the VIP had significantly higher recovery for one inoculation level.

Assurance® Enzyme Immunoassay Eight Hour Method for Detection of Enterohemorrhagic Escherichia coli O157:H7 in Raw and Cooked Beef (Modification of AOAC Official Method 996.10): Collaborative Study

AOAC Official Method 996.10, Assurance® Enzyme Immunoassay (EIA) for Escherichia coli O157:H7 (EHEC), was modified to incorporate a new enrichment protocol using BioControl EHEC8™ medium for testing raw and cooked beef. Foods were tested by EIA and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) enrichment conditions and the FDA Bacteriological Analytical Manual (BAM) isolation and confirmation techniques. A total of 14 collaborators participated. Raw and cooked ground beef were inoculated with E. coli O157:H7 at 2 different levels: a high level where predominantly positive results were expected, and a low level where fractional recovery was anticipated. Collaborators tested 378 test portions and controls by both the 8 h EIA and the USDA/FSIS enrichment methods, for a total of 756 test portions. Of the 378 paired test portions, 75 were positive and 212 were negative by both methods. Thirteen test portions were presumptively positive by EIA and could not be confirmed culturally; 30 were negative by EIA, but confirmed positive by culture; and 65 were negative by the culture method, but confirmed positive by the EIA method. There was no statistical difference between results obtained with the Assurance EIA for EHEC 8 h method and the culture method for raw ground beef. The Assurance EIA had a significantly higher recovery for cooked beef.

Method Extension Study to Validate Applicability of AOAC Official Method 997.03 Visual Immunoprecipitate Assay (VIP®) for Listeria monocytogenes and Related Listeria spp. from Environmental Surfaces: Collaborative Study

Test portions from 3 environmental surface types, representative of typical surfaces found in a food production facility, were analyzed by the Visual Immunoprecipitate assay (VIP®) and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) culture method for Listeria monocytogenes and related Listeria species. In all cases, naturally contaminated environmental test samples were collected from an actual food production facility by sponge or swab. Test samples from concrete surfaces were collected by both swab and sponge; sponge test samples were collected from rubber surfaces, and swabs were used to sample steel surfaces. Test portions from each surface type were simultaneously analyzed by both methods. A total of 27 laboratories, representing government agencies as well as private industry in both the United States and Canada, participated in the study. During this study, a total of 615 test portions and controls was analyzed and confirmed, of which 227 were positive and 378 were negative by both methods. Nine test portions were positive by culture, but negative by the VIP. Five test portions were negative by culture, but positive by the VIP. Four test portions were negative by VIP and by culture, but confirmed positive when VIP enrichment broths were subcultured to selective agars. The data reported here indicate that the VIP method and the USDA/FSIS culture method are statistically equivalent for detection of L. monocytogenes and related Listeria species from environmental surfaces taken by sponges or swabs.

Modification of Enrichment Protocols for TECRA Listeria Visual Immunoassay Method 995.22: Collaborative Study

A collaborative study was conducted to validate new enrichment methods for the TECRA Listeria Visual Immunoassay (TLVIA). These new methods incorporate a newly formulated medium, TECRA Listeria Enrichment Broth, which does not contain the highly toxic antifungal agent, cycloheximide. The new procedures will provide an alternative to the enrichment procedures described in AOAC Method 995.22. Three food types (raw ground beef, lettuce, and ice cream) were analyzed in the United States, and 2 food types (cooked turkey and cooked fish fillets) were analyzed in Australasia. Thirty collaborators participated in the study, 16 in Australasia and 14 in the United States. With the exception of one batch of ground beef, comparison of the proportion of positive test portions (p ≥ 0.05) showed no significant difference between the TLVIA and the reference method for the 5 foods at 3 inoculation levels. For the one batch of naturally contaminated raw ground beef, the TLVIA gave significantly more confirmed positive results than the reference method.

Profiling emergency department presentations of 14-15-year-olds in modern Ireland

BACKGROUND

Mid-adolescence, that twilight era when the human child transitions to adulthood, is an often overlooked developmental age yet harbours a subpopulation of patients with their own myriad of medical problems somewhat unique to their age group.

AIMS

Our study is aimed at reviewing the typical presentations to a paediatric emergency department of modern Irish teenagers in mid-adolescence, the profile of which has changed significantly over the past 10 years.

METHODS

Hospital electronic databases were used to conduct a retrospective review of the paediatric emergency department presentations of patients aged 14-15 years during the year of 2017. We collated data on the presenting complaint, background history, admission rate and medical specialities involved in each patient's care while in our Emergency Department.

RESULTS

A total of 1485 presentations were made, with 1363 being eligible for inclusion in this study. The results highlight the varied and challenging presentations (Table 1) and the high number of specialities required within emergency medicine to care for this unique population (Table 2).

CONCLUSION

The results highlight the most common presentations of this subgroup of patients, with trauma, in keeping with recent international data, being the most common presentation. The noted high frequency in the number of mental health/intoxication/self-harm presentations among the Irish teenagers in our region is consistent with trends reported in world literature and serves to emphasise one of the main challenges facing those working in paediatrics in Ireland over the next 10 years.

Neuroligin tuning of pharyngeal pumping reveals extrapharyngeal modulation of feeding in Caenorhabditis elegans

The integration of distinct sensory modalities is essential for behavioural decision making. In C aenorhabditis elegans, this process is coordinated by neural circuits that integrate sensory cues from the environment to generate an appropriate behaviour at the appropriate output muscles. Food is a multimodal cue that impacts the microcircuits to modulate feeding and foraging drivers at the level of the pharyngeal and body wall muscle, respectively. When food triggers an upregulation in pharyngeal pumping, it allows the effective ingestion of food. Here, we show that a C elegans mutant in the single gene orthologous to human neuroligins, nlg-1, is defective in food-induced pumping. This was not due to an inability to sense food, as nlg-1 mutants were not defective in chemotaxis towards bacteria. In addition, we found that neuroligin is widely expressed in the nervous system, including AIY, ADE, ALA, URX and HSN neurons. Interestingly, despite the deficit in pharyngeal pumping, neuroligin was not expressed within the pharyngeal neuromuscular network, which suggests an extrapharyngeal regulation of this circuit. We resolved electrophysiologically the neuroligin contribution to the pharyngeal circuit by mimicking food-dependent pumping and found that the nlg-1 phenotype is similar to mutants impaired in GABAergic and/or glutamatergic signalling. We suggest that neuroligin organizes extrapharyngeal circuits that regulate the pharynx. These observations based on the molecular and cellular determinants of feeding are consistent with the emerging role of neuroligin in discretely impacting functional circuits underpinning complex behaviours.

Yeast two-hybrid screening identifies MPZ-1 and PTP-1 as candidate scaffolding proteins of metabotropic glutamate receptors in Caenorhabditis elegans

The metabotropic glutamate receptors (mGluRs) are a class of G-protein-coupled receptor that undergo extensive interactions with scaffolding proteins, and this is intrinsic to their function as an important group of neuromodulators at glutamatergic synapses. The Caenorhabditis elegans nervous system expresses three metabotropic glutamate receptors, MGL-1, MGL-2 and MGL-3. Relatively little is known about how the function and signalling of these receptors is organised in C. elegans. To identify proteins that scaffold the MGL-1 receptor, we have conducted a yeast two-hybrid screen. Three of the interacting proteins, MPZ-1, NRFL-1 and PTP-1, displayed motifs characteristic of mammalian mGluR scaffolding proteins. Using cellular co-expression criterion, we show mpz-1 and ptp-1 exhibited overlapping expression patterns with subsets of mgl-1 neurons. This included neurones in the pharyngeal nervous system that control the feeding organ of the worm. The mGluR agonist L-CCG-I inhibits the activity of this network in wild-type worms, in an MGL-1 and dose-dependent manner. We utilised L-CCG-I to identify if MGL-1 function was disrupted in mutants with deletions in the mpz-1 gene. The mpz-1 mutants displayed a largely wild-type response to L-CCG-I, suggesting MGL-1 signalling is not overtly disrupted consistent with a non-obligatory modulatory function in receptor scaffolding. The selectivity of the protein interactions and overlapping expression identified here warrant further investigation of the functional significance of scaffolding of metabotropic glutamate receptor function.

Comparison of hyperspectral classification methods for the analysis of cerium oxide nanoparticles in histological and aqueous samples

Hyperspectral imaging (HSI) and classification are established methods that are being applied in new ways to the analysis of nanoscale materials in a variety of matrices. Typically, enhanced darkfield microscopy (EDFM)-based HSI data (also known as image datacubes) are collected in the wavelength range of 400-1000 nm for each pixel in a datacube. Utilising different spectral library (SL) creation methods, spectra from pixels in the datacube corresponding to known materials can be collected into reference spectral libraries (RSLs), which can be used to classify materials in datacubes of experimental samples using existing classification algorithms. In this study, EDFM-HSI was used to visualise and analyse industrial cerium oxide (CeO₂ ; ceria) nanoparticles (NPs) in rat lung tissues and in aqueous suspension. Rats were exposed to ceria NPs via inhalation, mimicking potential real-world occupational exposures. The lung tissues were histologically prepared: some tissues were stained with hematoxylin and eosin (H&E) and some were left unstained. The goal of this study was to determine how HSI and classification results for ceria NPs were influenced by (1) the use of different RSL creation and classification methods and (2) the application of those methods to samples in different matrices (stained tissue, unstained tissue, or aqueous solution). Three different RSL creation methods - particle filtering (PF), manual selection, and spectral hourglass wizard (SHW) - were utilised to create the RSLs of known materials in unstained and stained tissue, and aqueous suspensions, which were then used to classify the NPs in the different matrices. Two classification algorithms - spectral angle mapper (SAM) and spectral feature fitting (SFF) - were utilised to determine the presence or absence of ceria NPs in each sample. The results from the classification algorithms were compared to determine how each influenced the classification results for samples in different matrices. The results showed that sample matrix and sample preparation significantly influenced the NP classification thresholds in the complex matrices. Moreover, considerable differences were observed in the classification results when utilising each RSL creation and classification method for each type of sample. Results from this study illustrate the importance of appropriately selecting HSI algorithms based on specific material and matrix characteristics in order to obtain optimal classification results. As HSI is increasingly utilised for NP characterisation for clinical, environmental and health and safety applications, this investigation is important for further refining HSI protocols while ensuring appropriate data collection and analysis.

Bespoke video vignettes - an approach to enhancing reflective learning developed by dental undergraduates and their clinical teachers

This study explores the selective use of video as a medium to support reflective processes as related to dental undergraduate learning. With the objective of developing and enhancing high-quality adult dental care, the use of compiled video materials created in an undergraduate clinical setting was investigated. Video cameras were used to capture elements of reflection-in-action and reflection-on-action typically found during everyday clinical practice. 'Gold standard' or 'textbook outcomes' are rarely, if ever, fully achieved in dental practice. Real-life clinical experiences offer challenges and opportunities for both teachers and students to engage with reflective learning processes. The materials generated allowed for an experience of individual reflective learning and the creation of a data bank or archive with potential use for the benefit of a wider student cohort. Various aspects of the students' views and comments on the process of reflection were reported and explored by means of a semi-structured focus group moderated by a linked educational advisor.

Context-dependent regulation of feeding behaviour by the insulin receptor, DAF-2, in Caenorhabditis elegans

Insulin signalling plays a significant role in both developmental programmes and pathways modulating the neuronal signalling that controls adult behaviour. Here, we have investigated insulin signalling in food-associated behaviour in adult C. elegans by scoring locomotion and feeding on and off bacteria, the worm’s food. This analysis used mutants (daf-2, daf-18) of the insulin signalling pathway, and we provide evidence for an acute role for insulin signalling in the adult nervous system distinct from its impact on developmental programmes. Insulin receptor daf-2 mutants move slower than wild type both on and off food and showed impaired locomotory responses to food deprivation. This latter behaviour is manifest as a failure to instigate dispersal following prolonged food deprivation and suggests a role for insulin signalling in this adaptive response. Insulin receptor daf-2 mutants are also deficient in pharyngeal pumping on food and off food. Pharmacological analysis showed the pharynx of daf-2 is selectively compromised in its response to 5-HT compared to the excitatory neuropeptide FLP-17. By comparing the adaptive pharyngeal behaviour in intact worms and isolated pharyngeal preparations, we determined that an insulin-dependent signal extrinsic to the pharyngeal system is involved in feeding adaptation. Hence, we suggest that reactive insulin signalling modulates both locomotory foraging and pharyngeal pumping as the animal adapts to the absence of food. We discuss this in the context of insulin signalling directing a shift in the sensitivity of neurotransmitter systems to regulate the worm’s response to changes in food availability in the environment.

Cradle-to-farm gate environmental footprints of beef cattle production in Kansas, Oklahoma, and Texas

A comprehensive national assessment of the sustainability of beef is being conducted by the U.S. beef industry. The first of 7 regions to be analyzed is Kansas, Oklahoma, and Texas. A survey and visits conducted throughout the region provided data on common production practices. From these data, representative ranch and feedyard operations were defined and simulated for the varying climate and soil conditions throughout the region using the Integrated Farm System Model. These simulations predicted environmental impacts of each operation including cradle-to-farm gate footprints for greenhouse gas emissions, fossil-based energy use, nonprecipitation water use, and reactive N loss. Individual ranch and feedyard operations were linked to form 28 representative production systems. A weighted average of the production systems was used to determine the environmental footprints for the region where weighting factors were developed based on animal numbers reported in the survey and agricultural statistics data. Along with the traditional beef production systems, Holstein steer and cull cow production from the dairy industry in the region were also modeled and included. The carbon footprint of all beef produced was 18.3 ± 1.7 kg CO2 equivalents (CO2e)/kg carcass weight (CW) with the range in individual production systems being 13 to 25 kg CO2e/kg CW. Energy use, water use, and reactive N loss were 51 ± 4.8 MJ/kg CW, 2,470 ± 455 L/kg CW, and 138 ± 12 g N/kg CW, respectively. The major portion of each footprint except water use was associated with the cow-calf phase; most of the nonprecipitation water use was attributed to producing feed for the finishing phase. These data provide a baseline for comparison as new technologies and strategies are developed and implemented to improve the sustainability of cattle production. Production information also will be combined with processing, marketing, and consumer data to complete a comprehensive life cycle assessment of beef.

Metabotropic Glutamate Receptors: MODULATORS OF CONTEXT-DEPENDENT FEEDING BEHAVIOUR IN C. ELEGANS

Glutamatergic neurotransmission is evolutionarily conserved across animal phyla. A major class of glutamate receptors consists of the metabotropic glutamate receptors (mGluRs). In C. elegans, three mGluR genes, mgl-1, mgl-2, and mgl-3, are organized into three subgroups, similar to their mammalian counterparts. Cellular reporters identified expression of the mgls in the nervous system of C. elegans and overlapping expression in the pharyngeal microcircuit that controls pharyngeal muscle activity and feeding behavior. The overlapping expression of mgls within this circuit allowed the investigation of receptor signaling per se and in the context of receptor interactions within a neural network that regulates feeding. We utilized the pharmacological manipulation of neuronally regulated pumping of the pharyngeal muscle in the wild-type and mutants to investigate MGL function. This defined a net mgl-1-dependent inhibition of pharyngeal pumping that is modulated by mgl-3 excitation. Optogenetic activation of the pharyngeal glutamatergic inputs combined with electrophysiological recordings from the isolated pharyngeal preparations provided further evidence for a presynaptic mgl-1-dependent regulation of pharyngeal activity. Analysis of mgl-1, mgl-2, and mgl-3 mutant feeding behavior in the intact organism after acute food removal identified a significant role for mgl-1 in the regulation of an adaptive feeding response. Our data describe the molecular and cellular organization of mgl-1, mgl-2, and mgl-3. Pharmacological analysis identified that, in these paradigms, mgl-1 and mgl-3, but not mgl-2, can modulate the pharyngeal microcircuit. Behavioral analysis identified mgl-1 as a significant determinant of the glutamate-dependent modulation of feeding, further highlighting the significance of mGluRs in complex C. elegans behavior.

Fluensulfone is a nematicide with a mode of action distinct from anticholinesterases and macrocyclic lactones

Plant parasitic nematodes infest crops and present a threat to food security worldwide. Currently available chemical controls e.g. methyl bromide, organophosphates and carbamates have an unacceptable level of toxicity to non-target organisms and are being withdrawn from use. Fluensulfone is a new nematicide of the fluoroalkenyl thioether group that has significantly reduced environmental impact with low toxicity to non-target insects and mammals. Here, we show that the model genetic organism Caenorhabditis elegans is susceptible to the irreversible nematicidal effects of fluensulfone. Whilst the dose required is higher than that which has nematicidal activity against Meloidogyne spp. the profile of effects on motility, egg-hatching and survival is similar to that reported for plant parasitic nematodes. C. elegans thus provides a tractable experimental paradigm to analyse the effects of fluensulfone on nematode behaviour. We find that fluensulfone has pleiotropic actions and inhibits development, egg-laying, egg-hatching, feeding and locomotion. In the case of feeding and locomotion, an early excitation precedes the gross inhibition. The profile of these effects is notably distinct from other classes of anthelmintic and nematicide: the inhibition of motility caused by fluensulfone is not accompanied by the hypercontraction which is characteristic of organophosphates and carbamates and C. elegans mutants that are resistant to the carbamate aldicarb and the macrocyclic lactone ivermectin retain susceptibility to fluensulfone. These data indicate fluensulfone's mode of action is distinct from currently available nematicides and it therefore presents a promising new chemical entity for crop protection.

Measuring the viscosity of whole bovine lens using a fiber optic oxygen sensing system

PURPOSE

To obtain a better understanding of oxygen and nutrient transport within the lens, the viscosity of whole lenses was investigated using a fiber optic oxygen sensor (optode). The diffusion coefficient of oxygen was calculated using the Stokes-Einstein equation at the slip boundary condition.

METHODS

The optode was used to measure the oxygen decay signal in samples consisting of different glycerol/water solutions with known viscosities. The oxygen decay signal was fitted to a double exponential decay rate equation, and the lifetimes (tau) were calculated. It was determined that the tau-viscosity relationship is linear, which served as the standard curve. The same procedure was applied to fresh bovine lenses, and the unknown viscosity of the bovine lens was calculated from the tau-viscosity relationship.

RESULTS

The average viscosity in a whole bovine lens was determined to be 5.74 ± 0.88 cP by our method. Using the Stokes-Einstein equation at the slip boundary condition, the diffusion coefficient for oxygen was calculated to be 8.2 × 10(-6) cm(2)/s.

CONCLUSIONS

These data indicate a higher resistance to flow for oxygen and nutrients in the lens than what is currently assumed in the literature. Overall, this study allows a better understanding of oxygen transport within the lens.

A2E-mediated photochemical modification to fibronectin and its implications to age-related changes in Bruch's membrane

Lipofuscin accumulates normally with age and is more pronounced in retinal dystrophies such as age-related macular degeneration. The major bis-retinoid component of lipofuscin is A2E. In addition to cell damage effects by A2E, we have previously demonstrated that blue-light-mediated A2E leads to modifications in the basement membrane protein laminin. Therefore, the purpose of this study was to advance the understanding of A2E photooxidation effects on fibronectin, the major glycoprotein of Bruch's membrane. In this study, A2E was irradiated with blue light in the presence of a fibronectin peptide consisting of amino acids from the integrin binding region. The modification sites were identified via LC/MS. Our research indicated that blue light irradiation caused cleavage throughout the A2E molecule closest to the pyridinium ring, and attached to the fibronectin peptide preferentially at lysine and arginine residues. All of these reactions are similar to the Maillard reaction. Altogether this study suggests that blue-light-irradiated A2E modifies peptides and forms advance glycation endproducts. Furthermore, these results can be used to identify modifications that occur in Bruch's membrane in vivo.

Distinct molecular targets including SLO-1 and gap junctions are engaged across a continuum of ethanol concentrations in Caenorhabditis elegans

Ethanol (alcohol) interacts with diverse molecular effectors across a range of concentrations in the brain, eliciting intoxication through to sedation. Invertebrate models including the nematode worm Caenorhabditis elegans have been deployed for molecular genetic studies to inform on key components of these alcohol signaling pathways. C. elegans studies have typically employed external dosing with high (>250 mM) ethanol concentrations: A careful analysis of responses to low concentrations is lacking. Using the C. elegans pharyngeal system as a paradigm, we report a previously uncharacterized continuum of cellular and behavioral responses to ethanol from low (10 mM) to high (300 mM) concentrations. The complexity of these responses indicates that the pleiotropic action of ethanol observed in mammalian brain is conserved in this invertebrate model. We investigated two candidate ethanol effectors, the calcium-activated K(+) channel SLO-1 and gap junctions, and show that they contribute to, but are not sole determinants of, the low- and high-concentration effects, respectively. Notably, this study shows cellular and whole organismal behavioral responses to ethanol in C. elegans that directly equate to intoxicating through to supralethal blood alcohol concentrations in humans and provides an important benchmark for interpretation of paradigms that seek to inform on human alcohol use disorders.

NeuroChip: a microfluidic electrophysiological device for genetic and chemical biology screening of Caenorhabditis elegans adult and larvae

Genetic and chemical biology screens of C. elegans have been of enormous benefit in providing fundamental insight into neural function and neuroactive drugs. Recently the exploitation of microfluidic devices has added greater power to this experimental approach providing more discrete and higher throughput phenotypic analysis of neural systems. Here we make a significant addition to this repertoire through the design of a semi-automated microfluidic device, NeuroChip, which has been optimised for selecting worms based on the electrophysiological features of the pharyngeal neural network. We demonstrate this device has the capability to sort mutant from wild-type worms based on high definition extracellular electrophysiological recordings. NeuroChip resolves discrete differences in excitatory, inhibitory and neuromodulatory components of the neural network from individual animals. Worms may be fed into the device consecutively from a reservoir and recovered unharmed. It combines microfluidics with integrated electrode recording for sequential trapping, restraining, recording, releasing and recovering of C. elegans. Thus mutant worms may be selected, recovered and propagated enabling mutagenesis screens based on an electrophysiological phenotype. Drugs may be rapidly applied during the recording thus permitting compound screening. For toxicology, this analysis can provide a precise description of sub-lethal effects on neural function. The chamber has been modified to accommodate L2 larval stages showing applicability for small size nematodes including parasitic species which otherwise are not tractable to this experimental approach. We also combine NeuroChip with optogenetics for targeted interrogation of the function of the neural circuit. NeuroChip thus adds a new tool for exploitation of C. elegans and has applications in neurogenetics, drug discovery and neurotoxicology.

Impact of nursing home residence on hospital epidemiology of meticillin-resistant Staphylococcus aureus: a perspective from Asia

In a Singapore hospital practising meticillin-resistant Staphylococcus aureus (MRSA) admission screening, the relative risk for MRSA colonization for those admitted from nursing homes was 6.89 (95% confidence interval: 5.74-8.26; 41% of 190 vs 6.0% of 14,849). However, the MRSA burden on admission attributable to nursing home residence was low (6.9%). Risk factors independently associated with MRSA colonization in patients admitted from nursing homes were previous hospital admissions, broken skin, prior use of antibiotics and Chinese ethnicity. Low rates of nursing home use means that the overall impact of nursing home residence on MRSA in our hospital is low.

Meeting report: 2012 Caenorhabditis elegans Neurobiology meeting, EMBL Advanced Training Centre, Germany

Some of the finest minds in the field of Caenorhabditis elegans neurobiology were brought together from 14 June to 17 June 2012 in the small, quaint and picturesque German city of Heidelberg for the biannual C. elegans neurobiology conference. Held at the EMBL Advanced Training Centre and wonderfully organised by Diah Yulianti, Jean-Louis Bessereau, Gert Jansen and William Schafer, the meeting contained 62 verbal presentations and hundreds of posters that were displayed around the double-helical walkways that looped throughout the conference centre. Presentations on recent advances in microfluidics, cell ablation and targeted gene expression exemplified the strengths of C. elegans as a model organism, with these advances allowing detailed high-throughput analysis and study. Interesting behaviours that were previously poorly characterised were widely discussed, as were the advantages of C. elegans as a model for neurodevelopment and neurodegeneration and the investigation of neuropeptide function. The examples discussed in this meeting report seek to illustrate the breadth and depth of presentations given on these recurring topics.

An ongoing large outbreak of measles in Merseyside, England, January to June 2012

From 1 January to 30 June 2012, 359 confirmed and 157 probable cases of measles were reported in Merseyside, England. The most affected age groups were children under five years and young adults from 15 years of age. Most cases have been sporadic. There have been few outbreaks in nurseries; however, no outbreaks have been reported in schools. Of the cases eligible for vaccination, only 3% of the confirmed cases were fully immunised.

An ongoing large outbreak of measles in Merseyside, England, January to June 2012

From 1 January to 30 June 2012, 359 confirmed and 157 probable cases of measles were reported in Merseyside, England. The most affected age groups were children under five years and young adults from 15 years of age. Most cases have been sporadic. There have been few outbreaks in nurseries; however, no outbreaks have been reported in schools. Of the cases eligible for vaccination, only 3% of the confirmed cases were fully immunised.

Time-resolved autofluorescence imaging of human donor retina tissue from donors with significant extramacular drusen

PURPOSE

Time and spectrally resolved measurements of autofluorescence have the potential to monitor metabolism at the cellular level. Fluorophores that emit with the same fluorescence intensity can be discriminated from each other by decay time of fluorescence intensity after pulsed excitation. We performed time-resolved autofluorescence measurements on fundus samples from a donor with significant extramacular drusen.

METHODS

Tissue sections from two human donors were prepared and imaged with a laser scanning microscope. The sample was excited with a titanium-sapphire laser, which was tuned to 860 nm, and frequency doubled by a BBO crystal to 430 nm. The repetition rate was 76 MHz and the pulse width was 170 femtoseconds (fs). The time-resolved autofluorescence was recorded simultaneously in 16 spectral channels (445-605 nm) and bi-exponentially fitted.

RESULTS

RPE can be discriminated clearly from Bruch's membrane, drusen, and choroidal connective tissue by fluorescence lifetime. In RPE, bright fluorescence of lipofuscin could be detected with a maximum at 510 nm and extending beyond 600 nm. The lifetime was 385 ps. Different types of drusen were found. Most of them did not contain lipofuscin and exhibited a weak fluorescence, with a maximum at 470 nm. The lifetime was 1785 picoseconds (ps). Also, brightly emitting lesions, presumably representing basal laminar deposits, with fluorescence lifetimes longer than those recorded in RPE could be detected.

CONCLUSIONS

The demonstrated differentiation of fluorescent structures by their fluorescence decay time is important for interpretation of in vivo measurements by the new fluorescence lifetime imaging (FLIM) ophthalmoscopy on healthy subjects as well as on patients.

Site-specific phosphorylation of protein phosphatase 1 regulatory subunit 12A stimulated or suppressed by insulin

Protein phosphatase 1 (PP1) is one of the major phosphatases responsible for protein dephosphorylation in eukaryotes. So far, only few specific phosphorylation sites of PP1 regulatory subunit 12A (PPP1R12A) have been shown to regulate the PP1 activity. The effect of insulin on PPP1R12A phosphorylation is largely unknown. Utilizing a mass spectrometry based phosphorylation identification and quantification approach, we identified 21 PPP1R12A phosphorylation sites (7 novel sites, including Ser20, Thr22, Thr453, Ser478, Thr671, Ser678, and Ser680) and quantified 16 of them under basal and insulin stimulated conditions in hamster ovary cells overexpressing the insulin receptor (CHO/IR), an insulin sensitive cell model. Insulin stimulated the phosphorylation of PPP1R12A significantly at Ser477, Ser478, Ser507, Ser668, and Ser695, while simultaneously suppressing the phosphorylation of PPP1R12A at Ser509 (more than 2-fold increase or decrease compared to basal). Our data demonstrate that PPP1R12A undergoes insulin stimulated/suppressed phosphorylation, suggesting that PPP1R12A phosphorylation may play a role in insulin signal transduction. The novel PPP1R12A phosphorylation sites as well as the new insulin-responsive phosphorylation sites of PPP1R12A in CHO/IR cells provide targets for investigation of the regulation of PPP1R12A and the PPP1R12A-PP1cδ complex in insulin action and other signaling pathways in other cell models, animal models, and humans.

Compositional studies of human RPE lipofuscin: mechanisms of molecular modifications

The accumulation of lipofuscin has previously been implicated in several retinal diseases including Best's macular dystrophy, Stargardt's disease and age-related macular degeneration (AMD). Previously one of the major fluorophores of lipofuscin was identified as a bis-retinoid pyridinium salt called A2E, which is known to photochemically cause damage. In addition to A2E, there are numerous components in RPE lipofuscin that are unidentified. These compounds were determined to be structurally related to A2E by their fragmentation pattern with losses of 106, 190, 174 and/or 150 amu from the parent ion and the formation of fragments of ca 592 amu. The vast majority consists of relatively hydrophobic components corresponding to derivatized A2E with molecular weights in discrete groups of 800-900, 970-1080 and > 1200 m/z regions. In order to determine the mechanism of these modifications, A2E was chemically modified by; (1) the formation of specific esters, (2) reaction with specific aldehydes and (3) spontaneous auto-oxidation. The contribution of ester formation to the naturally occurring components of lipofuscin was discounted since their fragmentation patterns were different to those found in vivo. Alternatively, reactions with specific aldehydes result in nearly identical products as those found in vivo. Artificial aging of RPE lipofuscin gives a complex mixture of structurally related components. This results from the auto- and/or photooxidation of A2E to form aldehydes, which then back react with A2E giving a series of higher molecular weight products. The majority of these modifications result in compounds that are much more hydrophobic than A2E. These higher molecular weight materials have increased values of log P compared to A2E. This increase in hydrophobicity most likely aids in the sequestering of A2E into granules with the concomitant diminution of its reactivity. Therefore, these processes may serve as protective mechanisms for the RPE.

Compositional studies of human RPE lipofuscin

Age-related macular degeneration (AMD) is an ocular disease that causes visual loss and legal blindness in the elderly population. The etiology of AMD is complex and may include genetic predispositions, accumulation of lipofuscin and drusen, local inflammation and neovascularization. The accumulation of lipofuscin has been shown to precede the death of photoreceptor cells and the deterioration of the RPE. As a result, the determination of the photosensitive components of lipofuscin has been of major interest. One of these components, previously identified as a bis-retinoid pyridinium compound, is referred to as A2E. A2E has been characterized by mass spectrometry and is known to have a mass of 592 Da. Most remaining chromophores in RPE lipofuscin are structurally related to A2E as determined by their fragmentation pattern with losses of M ± 190, 174 and/or 150 Da. Analysis of lipofuscin from various donors indicated that the extracts consist of as many as 15 of these hydrophobic components, which are also observed to form spontaneously in vitro over extended periods of time. These consist of ca 90% of the A2E-like components in RPE lipofuscin and correspond to derivatized A2E with discrete molecular weights of 800-900 m/z, 970-1080 m/z and above 1200 m/z regions. It was determined that these species are formed from self-reaction of A2E oxidation products or their reaction with A2E itself to form higher molecular weight products. The majority of modifications are much more hydrophobic than A2E and exhibit increasingly higher values of log P. This acts as a driving force for the sequestering of A2E into granules resulting in a concomitant diminution of its reactivity in vivo.

Compositional studies of human RPE lipofuscin

Age-related macular degeneration (AMD) is an ocular disease that causes visual loss and legal blindness in the elderly population. The etiology of AMD is complex and may include genetic predispositions, accumulation of lipofuscin and drusen, local inflammation and neovascularization. The accumulation of lipofuscin has been shown to precede the death of photoreceptor cells and the deterioration of the RPE. As a result, the determination of the photosensitive components of lipofuscin has been of major interest. One of these components, previously identified as a bis-retinoid pyridinium compound, is referred to as A2E. A2E has been characterized by mass spectrometry and is known to have a mass of 592 Da. Most remaining chromophores in RPE lipofuscin are structurally related to A2E as determined by their fragmentation pattern with losses of M ± 190, 174 and/or 150 Da. Analysis of lipofuscin from various donors indicated that the extracts consist of as many as 15 of these hydrophobic components, which are also observed to form spontaneously in vitro over extended periods of time. These consist of ca 90% of the A2E-like components in RPE lipofuscin and correspond to derivatized A2E with discrete molecular weights of 800-900 m/z, 970-1080 m/z and above 1200 m/z regions. It was determined that these species are formed from self-reaction of A2E oxidation products or their reaction with A2E itself to form higher molecular weight products. The majority of modifications are much more hydrophobic than A2E and exhibit increasingly higher values of log P. This acts as a driving force for the sequestering of A2E into granules resulting in a concomitant diminution of its reactivity in vivo.

Age-related accumulation of 3-nitrotyrosine and nitro-A2E in human Bruch's membrane

Age-related macular degeneration (AMD) is a disease leading to severe visual loss and legal blindness in the elderly population. The pathophysiology of AMD is complex and may include genetic predispositions, accumulation of lipofuscin and drusen, local inflammation and neovascularization. Recently four independent research groups have identified a commonly inherited variant (Y402H) of the complement factor H gene in the genome from different groups of AMD patients. The Y402H variant of CFH significantly increases the risk of AMD and links the genetics of the disease with inflammation. During inflammation there is activation of inducible nitric oxide synthase and release of nitric oxide, which in principal could lead to non-enzymatic nitration within extracellular deposits and/or intrinsic extracellular matrix protein components of human Bruch's membrane. We have identified two biomarkers for non-enzymatic nitration in aged human Bruch's membrane, indicative of inflammation, that include 3-nitrotyrosine identified in Bruch's membrane preparations and nitrated A2E from the lipid soluble extract of the Bruch's membrane preparation. Approximately 30-40 times more A2E is observed in samples of the organic soluble extract of lipofuscin compared to the extract of Bruch's membrane. It is of interest to note that although A2E is a major constituent of RPE lipofuscin, nitrated A2E could not be detected in RPE extracts. We show here that nitro-A2E is a specific biomarker of nitrosative stress in Bruch's membrane and its concentration correlates directly with tissue age.