The relationship between serum astroglial and neuronal markers and AQP4 and MOG autoantibodies

BACKGROUND

Certain demyelinating disorders, such as neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) exhibit serum autoantibodies against aquaporin-4 (αAQP4) and myelin oligodendrocyte glycoprotein (αMOG). The variability of the autoantibody presentation warrants further research into subtyping each case.

METHODS

To elucidate the relationship between astroglial and neuronal protein concentrations in the peripheral circulation with occurrence of these autoantibodies, 86 serum samples were analyzed using immunoassays. The protein concentration of glial fibrillary acidic protein (GFAP), neurofilament light chain (NFL) and tau protein was measured in 3 groups of subcategories of suspected NMOSD: αAQP4 positive (n = 20), αMOG positive (n = 32) and αMOG/αAQP4 seronegative (n = 34). Kruskal-Wallis analysis, univariate predictor analysis, and multivariate logistic regression with ROC curves were performed.

RESULTS

GFAP and NFL concentrations were significantly elevated in the αAQP4 positive group (p = 0.003; p = 0.042, respectively), and tau was elevated in the αMOG/αAQP4 seronegative group (p < 0.001). A logistic regression model to classify serostatus was able to separate αAQP4 seropositivity using GFAP + tau, and αMOG seropositivity using tau. The areas under the ROC curves (AUCs) were 0.77 and 0.72, respectively. Finally, a combined seropositivity versus negative status logistic regression model was generated, with AUC = 0.80.

CONCLUSION

The 3 markers can univariately and multivariately classify with moderate accuracy the samples with seropositivity and seronegativity for αAQP4 and αMOG.

The relationship between serum astroglial and neuronal markers and AQP4 and MOG autoantibodies

Background

Certain demyelinating disorders, such as neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) exhibit serum autoantibodies against aquaporin-4 (αAQP4) and myelin oligodendrocyte glycoprotein (αMOG). The variability of the autoantibody presentation warrants further research into subtyping each case.

Methods

To elucidate the relationship between astroglial and neuronal protein concentrations in the peripheral circulation with occurrence of these autoantibodies, 86 serum samples were analyzed using immunoassays. The protein concentration of glial fibrillary acidic protein (GFAP), neurofilament light chain (NFL) and tau protein was measured in 3 groups of subcategories of suspected NMOSD: αAQP4 positive (n = 20), αMOG positive (n = 32) and αMOG/αAQP4 seronegative (n = 34). Kruskal-Wallis analysis, univariate predictor analysis, and multivariate logistic regression with ROC curves were performed.

Results

GFAP and NFL concentrations were significantly elevated in the αAQP4 positive group (p = 0.003; p = 0.042, respectively), and tau was elevated in the αMOG/αAQP4 seronegative group (p < 0.001). A logistic regression model to classify serostatus was able to separate αAQP4 seropositivity using GFAP + tau, and αMOG seropositivity using tau. The areas under the ROC curves (AUCs) were 0.77 and 0.72, respectively. Finally, a combined seropositivity versus negative status logistic regression model was generated, with AUC = 0.80.

Conclusion

The 3 markers can univariately and multivariately classify with moderate accuracy the samples with seropositivity and seronegativity for αAQP4 and αMOG.

Cerebrospinal fluid camk2a levels at baseline predict long-term progression in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) remains a highly unpredictable disease. Many hope that fluid biomarkers may contribute to better stratification of disease, aiding the personalisation of treatment decisions, ultimately improving patient outcomes.

OBJECTIVE

The objective of this study was to evaluate the predictive value of CSF brain-specific proteins from early in the disease course of MS on long term clinical outcomes.

METHODS

In this study, 34 MS patients had their CSF collected and stored within 5 years of disease onset and were then followed clinically for at least 15 years. CSF concentrations of 64 brain-specific proteins were analyzed in the 34 patient CSF, as well as 19 age and sex-matched controls, using a targeted liquid-chromatography tandem mass spectrometry approach.

RESULTS

We identified six CSF brain-specific proteins that significantly differentiated MS from controls (p < 0.05) and nine proteins that could predict disease course over the next decade. CAMK2A emerged as a biomarker candidate that could discriminate between MS and controls and could predict long-term disease progression.

CONCLUSION

Targeted approaches to identify and quantify biomarkers associated with MS in the CSF may inform on long term MS outcomes. CAMK2A may be one of several candidates, warranting further exploration.

Modelling the deactivation of Escherichia coli in Nigerian soils amended with differently treated manures

AIM

This study aimed to simulate deactivation of E. coli in soils amended with cattle manure after burning, anaerobic digestion, composting or without treatment.

METHOD AND RESULTS

The Weibull survival function was used to describe deactivation of E. coli. Parameters for each treatment were determined using E. coli measurements from manure-amended soils and evaluated against measurements at different application rates. A statistically significant correlation and high coincidence between the simulated and measured values was obtained. The simulations revealed that although anaerobic digestion or burning of cattle manure effectively reduced the E. coli loads to background levels, burning retained very little nitrogen, so the ash residue was ineffective as an organic fertiliser. Anaerobic digestion was most effective at reducing E. coli levels while retaining a high proportion of N in the bioslurry residue, but the persistence of E. coli was higher than in compost.

CONCLUSION

The results from this study suggest that the safest method for production of organic fertiliser would involve anaerobic digestion to reduce E. coli followed by composting to reduce its persistence.

The Contribution of Environmental Science to Mental Health Research: A Scoping Review

Mental health is influenced by multiple complex and interacting genetic, psychological, social, and environmental factors. As such, developing state-of-the-art mental health knowledge requires collaboration across academic disciplines, including environmental science. To assess the current contribution of environmental science to this field, a scoping review of the literature on environmental influences on mental health (including conditions of cognitive development and decline) was conducted. The review protocol was developed in consultation with experts working across mental health and environmental science. The scoping review included 202 English-language papers, published between 2010 and 2020 (prior to the COVID-19 pandemic), on environmental themes that had not already been the subject of recent systematic reviews; 26 reviews on climate change, flooding, air pollution, and urban green space were additionally considered. Studies largely focused on populations in the USA, China, or Europe and involved limited environmental science input. Environmental science research methods are primarily focused on quantitative approaches utilising secondary datasets or field data. Mental health measurement was dominated by the use of self-report psychometric scales. Measures of environmental states or exposures were often lacking in specificity (e.g., limited to the presence or absence of an environmental state). Based on the scoping review findings and our synthesis of the recent reviews, a research agenda for environmental science's future contribution to mental health scholarship is set out. This includes recommendations to expand the geographical scope and broaden the representation of different environmental science areas, improve measurement of environmental exposure, prioritise experimental and longitudinal research designs, and giving greater consideration to variation between and within communities and the mediating pathways by which environment influences mental health. There is also considerable opportunity to increase interdisciplinarity within the field via the integration of conceptual models, the inclusion of mixed methods and qualitative approaches, as well as further consideration of the socio-political context and the environmental states that can help support good mental health. The findings were used to propose a conceptual model to parse contributions and connections between environmental science and mental health to inform future studies.

Discovery of novel glioma serum biomarkers by proximity extension assay

BACKGROUND

Gliomas are among the most malignant tumors, with a very poor prognosis. Early diagnosis is highly desirable since it can help implement more effective treatments for smaller tumors, which have not yet extensively metastasized. Improving early diagnosis may facilitate access of patients to clinical trials and prepare them for the future availability of new disease-modifying treatments.

METHODS

We analyzed retrospective samples collected at diagnosis (before therapy initiation), with PEA (Olink Proteomics), quantifying about 3000 proteins. We utilized 30 plasmas from gliomas (20 glioblastomas, 5 anaplastic astrocytomas, 5 anaplastic oligodendrogliomas) and 20 meningiomas (as controls). We then analyzed the data to identify proteins which either alone, or in combination, could discriminate gliomas from meningiomas, or correlate with clinical and molecular alterations.

RESULTS

We identified 8 plasma proteins which were increased in gliomas vs. meningiomas (GFAP, NEFL, EDDM3B, PROK1, MMP3, CTRL, GP2, SPINT3) and 4 proteins which were decreased in gliomas vs. meningiomas (FABP4, ALDH3A1, IL-12B and OXT). Partition algorithms and logistic regression algorithms with two biomarkers (GFAP and FABP4) achieved sensitivity of 83% and 93% at 100% and 90% specificity, respectively. The strongest single marker was GFAP with an area under the ROC curve (AUC) of 0.86. The AUC for the GFAP-FABP4 combination was 0.98.

CONCLUSION

PEA is a powerful new proteomic technology for biomarker discovery. GFAP and a handful of other plasma biomarkers may be useful for early glioma detection and probably, prognosis.

STATEMENT

Detecting gliomas as early as possible is highly desirable since it can significantly improve the chances of effective treatments. Reliable glioma biomarkers can timely inform glioma patients about the efficacy of their prescribed treatment. Our results reveal some novel putative glioma markers that may prove valuable, when used alone or in combination, towards improved clinical care of gliomas. In order to better appreciate the potential usefulness of these markers, their performance needs to be further validated in a larger cohort of samples.

Pharmacy students' knowledge and confidence of COVID‐19 following an interactive didactic class

Background

COVID‐19 education for the pharmacy workforce is important to ensure pharmacists are optimizing patient care for the prevention and management of COVID‐19. However, there are currently no reports to our knowledge of education and training experiences for COVID‐19 prevention and management in the Doctor of Pharmacy (PharmD) curricula.

Objective

To evaluate pharmacy students' knowledge and confidence regarding COVID‐19 prevention and management before and after an interactive didactic class (IDC).

Methods

A multicenter, quasi‐experimental, cross‐sectional survey study was performed among pharmacy students before and after IDC on COVID‐19 at two schools of pharmacy. The IDC on COVID‐19 consisted of student‐led presentations on a COVID‐19 drug, an infectious disease pharmacist faculty‐led interactive lecture on COVID‐19 prevention and management, and clinical case vignettes to assess COVID‐19 management strategies. An anonymous, voluntary, electronic survey was distributed to students (n = 85) before and after. The pre‐ and postintervention survey contained 10 COVID‐19 knowledge‐based questions and multi‐step, 5‐point Likert scale statements related to COVID‐19 prevention and management confidence. The postintervention survey also evaluated students' perceptions of the COVID‐19 IDC. Descriptive statistics were performed, and Student t test was used to compare pre‐ and postintervention responses.

Results

About 61 surveys were completed resulting in a response rate of 72%. COVID‐19 knowledge scores (mean ± SD) increased overall following the IDC (5.9 ± 1.31 vs 8.6 ± 1.29). Pharmacy students' COVID‐19 confidence scores (mean ± SD) also improved following the IDC (2.66 ± 0.75 vs 4.03 ± 0.53). Students performed well on the COVID‐19 clinical case vignettes with a mean ± SD score of 22.41 ± 0.46 out of 25. Pharmacy students' perceptions of the IDC on COVID‐19 were also positive overall.

Conclusion

Pharmacy students' knowledge and confidence of COVID‐19 prevention and management improved following an IDC. This may be an effective strategy to provide COVID‐19 education during the PharmD curricula.

Instruction and Simulation to Improve Pharmacy Students' Knowledge and Confidence Regarding Assessment of Penicillin Allergies

Objective. To evaluate pharmacy students' knowledge of and confidence regarding penicillin allergy assessment and skin testing (PAAST) before and after a focused didactic instruction and simulation (FDIS).Methods. A multicenter, quasi-experimental, cross-sectional survey study was performed among pharmacy students before and after FDIS on PAAST at two schools of pharmacy. The FDIS on PAAST consisted of an infectious disease faculty-led seminar, student-led penicillin allergy counseling interviews, penicillin skin testing simulation, and case studies to assess penicillin allergy scenarios and management. An anonymous, voluntary, electronic survey was distributed to students (n=159) before and after the FDIS. The pre- and post-intervention survey contained 10 PAAST knowledge-based questions and multi-step, five-point Likert scale statements related to students' confidence in PAAST. The post-intervention survey also evaluated students' perceptions of the FDIS on PAAST. Descriptive statistics were performed, and the Student t test was used to compare pre- and post-intervention responses.Results. One hundred forty-three surveys were completed, resulting in a survey response rate of 90%. Students' PAAST knowledge scores (mean±SD) increased overall following the FDIS on PAAST (6.67±1.51 vs 7.81±1.39). Knowledge scores increased considerably for questions related to penicillin allergy consequences, cross-reactivity, and correct steps of PAAST. Pharmacy students' PAAST confidence scores (mean±SD) also improved following the interactive instruction and simulation (2.30±0.7 vs 3.22±0.67) with considerable confidence increases in penicillin skin testing. Pharmacy students' perceptions of the FDIS on PAAST were also positive overall.Conclusion. Pharmacy students' knowledge and confidence of PAAST improved following FDIS. This may be an effective strategy to implement PAAST education during pharmacy school.

Impacts of different treatment methods for cattle manure on the spread of faecal indicator organisms from soil to lettuce in Nigeria

AIM

This study investigated impacts of different organic waste treatment methods on reduction and spread of faecal indicator organisms to food crops in a developing country.

METHODS AND RESULTS

Fresh cattle manure was subjected to three different treatments; anaerobic digestion, burning and composting. Escherichia coli, coliforms and nitrogen content of cattle manure were measured before and after treatment in the amended soil and harvested lettuce. All treatments significantly reduced E. coli and coliform counts but differed in the ratio of E. coli or coliforms to nitrogen. Application of the recommended nitrogen dose of 120 kg ha-1 as bioslurry resulted in significantly lower E. coli and coliform contamination of soil than the same nitrogen rate applied as compost or ash. The E. coli content of lettuces grown on soil amended with treated wastes at recommended rates did not differ between treatments but was significantly lower than in lettuces grown on soil amended with untreated manure.

CONCLUSIONS

Treatment of manure before use as an organic fertilizer significantly reduces potential contamination of both soil and food crops with E. coli and coliforms. To best reduce the spread of E. coli from organic fertilizers, manures should be treated by anaerobic digestion.

SIGNIFICANCE AND IMPACT OF THE STUDY

Information from this study quantifies potential risks associated with use of manures in growing food crops by determining the ratio between pathogen content and required nitrogen application rate.

An agent-based model that simulates the spatio-temporal dynamics of sources and transfer mechanisms contributing faecal indicator organisms to streams. Part 1: Background and model description

A new Model for the Agent-based simulation of Faecal Indicator Organisms (MAFIO) is developed that attempts to overcome limitations in existing faecal indicator organism (FIO) models arising from coarse spatial discretisations and poorly-constrained hydrological processes. MAFIO is a spatially-distributed, process-based model presently designed to simulate the fate and transport of agents representing FIOs shed by livestock at the sub-field scale in small (<10 km²) agricultural catchments. Specifically, FIO loading, die-off, detachment, surface routing, seepage and channel routing are modelled on a regular spatial grid. Central to MAFIO is that hydrological transfer mechanisms are simulated based on a hydrological environment generated by an external model for which it is possible to robustly determine the accuracy of simulated catchment hydrological functioning. The spatially-distributed, tracer-aided ecohydrological model EcH₂O-iso is highlighted as a possible hydrological environment generator. The present paper provides a rationale for and description of MAFIO, whilst a companion paper applies the model in a small agricultural catchment in Scotland to provide a proof-of-concept.

An agent-based model that simulates the spatio-temporal dynamics of sources and transfer mechanisms contributing faecal indicator organisms to streams. Part 2: Application to a small agricultural catchment

The new Model for the Agent-based simulation of Faecal Indicator Organisms (MAFIO) is applied to a small (0.42 km²) Scottish agricultural catchment to simulate the dynamics of E. coli arising from sheep and cattle farming, in order to provide a proof-of-concept. The hydrological environment for MAFIO was simulated by the "best" ensemble run of the tracer-aided ecohydrological model EcH₂O-iso, obtained through multi-criteria calibration to stream discharge (MAE: 1.37 L s^-1) and spatially-distributed stable isotope data (MAE: 1.14-3.02‰) for the period April-December 2017. MAFIO was then applied for the period June-August for which twice-weekly E. coli loads were quantified at up to three sites along the stream. Performance in simulating these data suggested the model has skill in capturing the transfer of faecal indicator organisms (FIOs) from livestock to streams via the processes of direct deposition, transport in overland flow and seepage from areas of degraded soil. Furthermore, its agent-based structure allowed source areas, transfer mechanisms and host animals contributing FIOs to the stream to be quantified. Such information is likely to have substantial value in the context of designing and spatially-targeting mitigation measures against impaired microbial water quality. This study also revealed, however, that avenues exist for improving process conceptualisation in MAFIO (e.g. to include FIO contributions from wildlife) and highlighted the need to quantitatively assess how uncertainty in the spatial extent of surface flow paths in the simulated hydrological environment may affect FIO simulations. Despite the consequent status of MAFIO as a research-level model, its encouraging performance in this proof-of-concept study suggests the model has significant potential for eventual incorporation into decision support frameworks.

The Impact of the Duration of Antibiotic Therapy in Patients With Community-Onset Pneumonia on Readmission Rates: A Retrospective Cohort Study

BACKGROUND

Recent publications have confirmed that 70% of hospitalized adults with uncomplicated community-acquired pneumonia and health-care-associated pneumonia are prescribed a duration therapy that exceeds current guideline recommendations.

OBJECTIVE

The primary objective is to evaluate the relationship between antibiotic duration and all-cause 30-day readmission rates. Secondary outcomes include pneumonia-specific 30-day readmission rate and identification of risk factors for readmission.

METHODS

Patients aged ≥18 years with a primary diagnosis of pneumonia from January 1, 2016, to December 31, 2016, were included in this single-center, retrospective cohort study. Patients were categorized by antibiotic therapy duration of ≤7 days (n = 139) or >7 days (n = 286), and outcomes were analyzed in both bivariate and multivariate models. A multivariate logistic regression was used to assess the relationship between all-cause 30-day readmission and antibiotic days.

RESULTS

Baseline characteristics were not significantly different between the 2 groups. All-cause 30-day readmission rates were 15.8% and 15.5% for patients who received ≤7 days versus >7 days of antibiotics, respectively (P = .95). Pneumonia-specific 30-day readmission occurred in 3.6% of patients who received antibiotics for ≤7 days compared to 3.5% of patients who received antibiotics for >7 days (P = .95). Multivariate logistic regression showed no statistically significant association between readmission rate and antibiotic duration of >7 days. Statistically significant risk factors for readmission identified by logistic regression include ≥3 hospital admissions within the previous year, a hematocrit <30% at discharge, a history of chronic obstructive pulmonary disorder (COPD), and weight.

CONCLUSION

The use of prolonged antibiotic therapy for the treatment of community-onset pneumonia was not associated with a decrease in all-cause or pneumonia-specific 30-day readmission rates.

Penicillin Allergy Assessment and Skin Testing in the Outpatient Setting

Penicillin allergies are among of the most commonly reported allergies, yet only 10% of these patients are truly allergic. This leads to potential inadvertent negative consequences for patients and makes treatment decisions challenging for clinicians. Thus, allergy assessment and penicillin skin testing (PST) are important management strategies to reconcile and clarify labeled penicillin allergies. While PST is more common in the inpatient setting where the results will immediately impact antibiotic management, this process is becoming of increasing importance in the outpatient setting. PST in the outpatient setting allows clinicians to proactively de-label and educate patients accordingly so beta-lactam antibiotics may be appropriately prescribed when necessary for future infections. While allergists have primarily been responsible for PST in the outpatient setting, there is an increasing role for pharmacist involvement in the process. This review highlights the importance of penicillin allergy assessments, considerations for PST in the outpatient setting, education and advocacy for patients and clinicians, and the pharmacist’s role in outpatient PST.

Assessing Risk of E. coli Resuspension from Intertidal Estuarine Sediments: Implications for Water Quality

Estuarine sediments are a reservoir for faecal bacteria, such as E. coli, where they reside at greater concentrations and for longer periods than in the overlying water. Faecal bacteria in sediments do not usually pose significant risk to human health until resuspended into the water column, where transmission routes to humans are facilitated. The erosion resistance and corresponding E. coli loading of intertidal estuarine sediments was monitored in two Scottish estuaries to identify sediments that posed a risk of resuspending large amounts of E. coli. In addition, models were constructed in an attempt to identify sediment characteristics leading to higher erosion resistance. Sediments that exhibited low erosion resistance and a high E. coli loading occurred in the upper- and mid-reaches of the estuaries where sediments had higher organic content and smaller particle sizes, and arose predominantly during winter and autumn, with some incidences during summer. Models using sediment characteristics explained 57.2% and 35.7% of sediment shear strength and surface stability variance respectively, with organic matter content and season being important factors for both. However large proportions of the variance remained unexplained. Sediments that posed a risk of resuspending high amounts of faecal bacteria could be characterised by season and sediment type, and this should be considered in the future modelling of bathing water quality.

Factors affecting the spatial and temporal distribution of E. coli in intertidal estuarine sediments

Microbiological water quality monitoring of bathing waters does not account for faecal indicator organisms in sediments. Intertidal deposits are a significant reservoir of FIOs and this indicates there is a substantial risk to bathers through direct contact with the sediment, or through the resuspension of bacteria to the water column. Recent modelling efforts include sediment as a secondary source of contamination, however, little is known about the driving factors behind spatial and temporal variation in FIO abundance. E. coli abundance, in conjunction with a wide range of measured variables, was used to construct models to explain E. coli abundance in intertidal sediments in two Scottish estuaries. E. coli concentrations up to 6 log₁₀ CFU 100 g dry wt^-1 were observed, with optimal models accounting for E. coli variation up to an adjusted R² of 0.66. Introducing more complex models resulted in overfitting of models, detrimentally affected the transferability of models between datasets. Salinity was the most important single variable, with season, pH, colloidal carbohydrates, organic content, bulk density and maximum air temperature also featuring in optimal models. Transfer of models, using only lower cost variables, between systems explained an average deviance of 42%. This study demonstrates the potential for cost-effective sediment characteristic monitoring to contribute to FIO fate and transport modelling and consequently the risk assessment of bathing water safety.

The role of zeta potential in the adhesion of E. coli to suspended intertidal sediments

The extent of pathogen transport to and within aquatic systems depends heavily on whether the bacterial cells are freely suspended or in association with suspended particles. The surface charge of both bacterial cells and suspended particles affects cell-particle adhesion and subsequent transport and exposure pathways through settling and resuspension cycles. This study investigated the adhesion of Faecal Indicator Organisms (FIOs) to natural suspended intertidal sediments over the salinity gradient encountered at the transition zone from freshwater to marine environments. Phenotypic characteristics of three E. coli strains, and the zeta potential (surface charge) of the E. coli strains and 3 physically different types of intertidal sediments was measured over a salinity gradient from 0 to 5 Practical Salinity Units (PSU). A batch adhesion microcosm experiment was constructed with each combination of E. coli strain, intertidal sediment and 0, 2, 3.5 and 5 PSU. The zeta potential profile of one E. coli strain had a low negative charge and did not change in response to an increase in salinity, and the remaining E. coli strains and the sediments exhibited a more negative charge that decreased with an increase in salinity. Strain type was the most important factor in explaining cell-particle adhesion, however adhesion was also dependant on sediment type and salinity (2, 3.5 PSU > 0, 5 PSU). Contrary to traditional colloidal (Derjaguin, Landau, Vervey, and Overbeek (DLVO)) theory, zeta potential of strain or sediment did not correlate with cell-particle adhesion. E. coli strain characteristics were the defining factor in cell-particle adhesion, implying that diverse strain-specific transport and exposure pathways may exist. Further research applying these findings on a catchment scale is necessary to elucidate these pathways in order to improve accuracy of FIO fate and transport models.

Ciprofloxacin for the treatment of Cardiobacterium hominis prosthetic valve endocarditis

Prosthetic valve endocarditis due to Cardiobacterium hominis is rare and recommended therapy includes a third generation cephalosporin. We report a case of Cardiobacterium hominis endocarditis post transcatheter aortic valve replacement in a patient with significant beta-lactam antimicrobial sensitivities who was successfully treated with ciprofloxacin monotherapy in conjunction with surgery.

Case of antibiotic-associated diarrhea caused by Staphylococcus aureus enterocolitis

PURPOSE

A case of Staphylococcus aureus enterocolitis (SEC) misdiagnosed as toxin-negative Clostridium difficile is reported.

SUMMARY

An 82-year-old white man weighing 50 kg (body mass index, 16.8 kg/m(2)) was transported from an assisted living facility to the emergency department with the chief complaints of weakness, nausea, and diarrhea for one week and one bright-red stool on the morning of admission. Before hospital admission, he was treated for a urinary tract infection with ciprofloxacin 500 mg twice daily for 10 days. Stool cultures were negative for C. difficile but positive for S. aureus. The antimicrobial stewardship pharmacist recommended treatment with vancomycin 125 mg orally every 6 hours for staphylococcal colitis. Oral vancomycin was discontinued after three doses on the morning of hospital day 8 after a gastroenterology consultation. Within 48 hours of the discontinuation of oral vancomycin, the patient had eight stools per day. Vancomycin was reinitiated and the patient's symptoms began to again improve. On hospital day 19, the patient was discharged with a prescription for 7 more days of therapy with vancomycin (to complete a 15-day course) and a diagnosis of toxin-negative C. difficile, despite having symptoms consistent with SEC and an enteric culture positive for S. aureus.

CONCLUSION

An 82-year-old man was transferred from an assisted living facility to the hospital with profuse diarrhea and dehydration. Enteric cultures were positive for methicillin-resistant S. aureus with multiple negative C. difficile toxin B assays. Appropriate therapy was delayed and the patient potentially misdiagnosed with toxin-negative C. difficile when the clinical symptoms and diagnostic testing were consistent with SEC.

Molecular tools for bathing water assessment in Europe: Balancing social science research with a rapidly developing environmental science evidence-base

The use of molecular tools, principally qPCR, versus traditional culture-based methods for quantifying microbial parameters (e.g., Fecal Indicator Organisms) in bathing waters generates considerable ongoing debate at the science-policy interface. Advances in science have allowed the development and application of molecular biological methods for rapid (~2 h) quantification of microbial pollution in bathing and recreational waters. In contrast, culture-based methods can take between 18 and 96 h for sample processing. Thus, molecular tools offer an opportunity to provide a more meaningful statement of microbial risk to water-users by providing near-real-time information enabling potentially more informed decision-making with regard to water-based activities. However, complementary studies concerning the potential costs and benefits of adopting rapid methods as a regulatory tool are in short supply. We report on findings from an international Working Group that examined the breadth of social impacts, challenges, and research opportunities associated with the application of molecular tools to bathing water regulations.

Clay mineral type effect on bacterial enteropathogen survival in soil

Enteropathogens released into the environment can represent a serious risk to public health. Soil clay content has long been known to have an important effect on enteropathogen survival in soil, generally enhancing survival. However, clay mineral composition in soils varies, and different clay minerals have specific physiochemical properties that would be expected to impact differentially on survival. This work investigated the effect of clay materials, with a predominance of a particular mineral type (montmorillonite, kaolinite, or illite), on the survival in soil microcosms over 96 days of Listeria monocytogenes, Salmonella Dublin, and Escherichia coli O157. Clay mineral addition was found to alter a number of physicochemical parameters in soil, including cation exchange capacity and surface area, and this was specific to the mineral type. Clay mineral addition enhanced enteropathogen survival in soil. The type of clay mineral was found to differentially affect enteropathogen survival and the effect was enteropathogen-specific.

Criterion validity of the GMFM-66 item set and the GMFM-66 basal and ceiling approaches for estimating GMFM-66 scores

AIM

The aim of this study was to compare the accuracy of two abbreviated approaches for estimating Gross Motor Function Measure 66 (GMFM-66) scores against the full GMFM-66 and to explore their strengths and limitations.

METHOD

An existing dataset (n=224) comprising children aged 1 to 13 years (mean age 6y 11mo, SD 4y 6mo; 132 males, 92 females) with cerebral palsy (CP) of all Gross Motor Function Classification System (GMFCS) levels was used to compare the validity of the item set version (GMFM-66-IS) and the basal and ceiling version (GMFM-66-B&C) with the full GMFM-66 scores. Follow-up assessment at 1 year (n=109) allowed evaluation of change scores and accuracy at a single point in time.

RESULTS

The cross-sectional agreement was excellent for both abbreviated measures (all intraclass correlation coefficients [ICCs] >0.98). When measuring change over time, both the GMFM-66-IS and the GMFM-66-B&C showed good agreement for children with bilateral CP (ICCs >0.9). However, the GMFM-66-IS assessed change over 1 year more accurately than the GMFM-66-B&C in children with unilateral CP (ICC=0.89 vs ICC=0.58; 95% confidence intervals do not overlap).

INTERPRETATION

Both approaches for estimating GMFM-66 scores are accurate at a single point in time. If the primary goal of assessment is to measure change, the full GMFM-66 should still be regarded as the criterion standard. The GMFM-66-IS should be the preferred shortened measure for children with unilateral CP.

Prevalence and survival of potential pathogens in source-segregated green waste compost

Composting of source-separated green waste (SSGW) is essential to meet the EU Landfill Directive target and agricultural land is considered a significant market for the resulting composts. A critical review of the literature was performed to evaluate the potential for pathogens to enter the composting process via SSGW feedstocks and the likelihood of their survival of the composting process and subsequent application to land. This is discussed in the context of application of other organic wastes to land. It was concluded that zoonoses such as verotoxigenic Escherichia coli and Salmonella spp. are unlikely to survive and effective composting process, whereas spore forming organisms are more resistant to composting but are also ubiquitous in the environment. Adherence to existing guidelines, such as those for farm yard manures, is likely to provide a rational degree of health protection for humans and livestock.

Risk assessment of the use of PAS100 green composts in sheep and cattle production in Scotland

A generalized quantitative risk assessment for the use of source-segregated green waste (SSGW) compost use in livestock production is presented. This assessment focussed on potential risks associated with a specific product, PAS100 compost that meets the UK publicly available specification 100 and represents the majority of compost available for use in extensive Scottish livestock systems. A hazard screening approach was used to identify all potentially hazardous agents present in compost. A total of 497 potentially hazardous agents were screened, with 147 finally put forward for quantitative risk assessment. Scenarios modelled in the assessment included surface application of compost to grazing land and also incorporation into soil and subsequent uptake by fodder crops. Risk estimates were compared to those associated with six comparator materials, including various sludges, slurries and farm yard manures. Overall, five potentially hazardous agents (PCB28, PCB138, PCB153, 1,2,3,4,6,7,8-HpCDD, Clopyralid) returned a hazard quotient >1 but within margins of uncertainty, indicating that further investigation may be required. Within the limitations of available information, SSGW compost was found to pose less risk to grazing livestock, or the environment, than other commonly-used soil amendments. While this assessment relates to a specific product/standard used in the UK, the methodology could easily be applied to other composts/products/situations. Therefore these results have wider applicability.

Using knowledge brokers to facilitate the uptake of pediatric measurement tools into clinical practice: a before-after intervention study

Background

The use of measurement tools is an essential part of good evidence-based practice; however, physiotherapists (PTs) are not always confident when selecting, administering, and interpreting these tools. The purpose of this study was to evaluate the impact of a multifaceted knowledge translation intervention, using PTs as knowledge brokers (KBs) to facilitate the use in clinical practice of four evidence-based measurement tools designed to evaluate and understand motor function in children with cerebral palsy (CP). The KB model evaluated in this study was designed to overcome many of the barriers to research transfer identified in the literature.

Methods

A mixed methods before-after study design was used to evaluate the impact of a six-month KB intervention by 25 KBs on 122 practicing PTs' self-reported knowledge and use of the measurement tools in 28 children's rehabilitation organizations in two regions of Canada. The model was that of PT KBs situated in clinical sites supported by a network of KBs and the research team through a broker to the KBs. Modest financial remuneration to the organizations for the KB time (two hours/week for six months), ongoing resource materials, and personal and intranet support was provided to the KBs. Survey data were collected by questionnaire prior to, immediately following the intervention (six months), and at 12 and 18 months. A mixed effects multinomial logistic regression was used to examine the impact of the intervention over time and by region. The impact of organizational factors was also explored.

Results

PTs' self-reported knowledge of all four measurement tools increased significantly over the six-month intervention, and reported use of three of the four measurement tools also increased. Changes were sustained 12 months later. Organizational culture for research and supervisor expectations were significantly associated with uptake of only one of the four measurement tools.

Conclusions

KBs positively influenced PTs' self-reported knowledge and self-reported use of the targeted measurement tools. Further research is warranted to investigate whether this is a feasible, cost-effective model that could be used more broadly in a rehabilitation setting to facilitate the uptake of other measurement tools or evidence-based intervention approaches.

Leaching of bioluminescent Escherichia coli O157:H7 from sheep and cattle faeces during simulated rainstorm events

AIMS

Development of a novel inoculation technique to improve the current methods of determining the leaching of Escherichia coli O157:H7 from faeces.

METHODS AND RESULTS

Ruminant faeces were inoculated with a high [c. 10(7) colony forming units (CFU) g(-1)] or low (c. 10(4) CFU g(-1)) load of a lux-marked strain of E. coli O157:H7 via injection, and subjected to four simulated heavy rainfall events. The population density and metabolic activity of E. coli O157:H7 recovered within the leachate was determined following each simulated rain event and compared with the indigenous E. coli population. The concentration of E. coli O157:H7 in the leachates followed a similar trend to that of nonpathogenic E. coli. Significantly greater densities of generic and pathogenic E. coli were recovered in the leachates generated from sheep faeces compared with cattle faeces. Pathogen metabolic activity was also significantly greater in sheep faeces.

CONCLUSIONS

Our findings show that E. coli O157:H7 may readily leach from ruminant faeces during rain events. The bacterium leaches more freely from sheep faeces than from cattle faeces and displays greater metabolic activity within sheep leachate.

SIGNIFICANCE AND IMPACT OF THE STUDY

A novel inoculation technique was developed that allowed the determination of both population density and cellular activity of E. coli O157:H7 in leachate derived from faeces.

Development and validation of item sets to improve efficiency of administration of the 66-item Gross Motor Function Measure in children with cerebral palsy

AIM

To develop an algorithmic approach to identify item sets of the 66-item version of the Gross Motor Function Measure (GMFM-66) to be administered to individual children, and to examine the validity of the algorithm for obtaining a GMFM-66 score.

METHOD

An algorithmic approach was used to identify item sets of the GMFM-66 (GMFM-66-IS) using data from 95 males and 79 females with cerebral palsy (CP; mean age 14y 7mo, SD 1y 8mo, range 12y 7mo to 17y 8mo). The GMFM-66-IS scores were then validated using combined data from three Dutch studies involving 134 males and 92 females with CP (mean age 7y, SD 4y 6mo, range 1y 4mo to 13y 8mo), representing all levels of the Gross Motor Function Classification System.

RESULTS

The final algorithm contains three decision items from the GMFM-66 that determine which one of four item sets to administer. The GMFM-66-IS has excellent agreement with the full GMFM-66 both at a single assessment (intraclass correlation coefficient [ICC]=0.994, 95% confidence intervals [CI] 0.993-0.996) and across repeat assessments (ICC=0.92, 95% CI 0.89-0.95).

INTERPRETATION

The GMFM-66-IS is a promising alternative to the full GMFM-66. Users should be consistent in their choice of measure (GMFM-66 or GMFM-66-IS) on repeat testing and clearly identify which method was used.

Heat and lime-treatment as effective control methods for E. coli O157:H7 in organic wastes

Land-application of abattoir wastes is economically appealing and may provide an effective means of closing the nutrient cycling loop. This practise is constrained, however, by legislation which necessitates pre-treatment to remove pathogenic micro-organisms prior to land-spreading. Here we investigated whether heat-treatment or lime addition could eliminate Escherichia coli O157:H7 from three contrasting abattoir wastes. We found that treatment at 60 degrees C for 10 min effectively eradicated the organism while treatment for the same length of time at 50 degrees C led to 2-4 log reductions, but not a complete kill. Temperatures of 72 degrees C induced waste solidification rendering its use impractical. The potential for re-growth in heat-treated and untreated wastes was also investigated. Survival was significantly greater in heat-treated wastes, although the difference was less than half a log unit in magnitude. This effect of heat-treatment on pathogen survival appeared to be ameliorated when wastes were mixed with soil. No viable E. coli O157:H7 cells were recovered from any waste after application of lime (CaO) at a rate of 10 gl(-1), even after enrichment. Our results indicate that pasteurisation-style or liming treatments may provide a suitable alternative method for reducing pathogen loads in abattoir wastes, so that they can be applied to land with minimal biological risk.

Essential oils for the disinfection of grey water

Although the antimicrobial properties of many plant essential oils (EOs) are well known, their application for the disinfection of water has received little attention. In this study, their use as alternative 'natural' disinfectants for grey water reuse was assessed. Toxicity screening of eight EOs and their components highlighted origanum oil (Thymus capitatus) and carvacrol as exerting the most antimicrobial activity. Over a 30-min contact time, origanum EO concentrations of up to 94 mg L(-1) had minimal effect on total coliform concentrations in the grey water while a concentration of 468 mg L(-1) rendered total coliforms non-detectable in 100mL grey water. Coliform inactivation was found to increase with EO contact time. Organic concentration and particulate size in grey water were shown to reduce the efficacy of disinfection with origanum EO. Origanum EO prevented regrowth of coliform bacteria in reed bed-treated grey water for up to 14 days at a concentration of 468 mg L(-1), with or without prior disinfection by ultraviolet (UV) light. Based on the disinfection data reported here, the production of sufficient origanum EO for the disinfection of grey water for reuse with toilet flushing, would require approximately 35 times the average land area of a UK household.

Ultraviolet (UV) disinfection of grey water: particle size effects

The impact of water quality on the ultraviolet (UV) disinfection of grey water was investigated with reference to urban water reuse. Direct UV disinfection of grey water did not meet the stringent California State Title 22 criteria for unrestricted urban water reuse due to the presence of particulate material ranging from < 1 to > or = 2000 microm in size. Grey water was manipulated by settling to produce fractions of varying particle size distributions and blending was employed post-disinfection to extract particle-associated coliforms (PACs). The efficacy of UV disinfection was found to be linked to the particle size of the grey water fractions. The larger particle size fractions with a mean particle size of 262 microm and above were observed to shield more coliforms from UV light than did the smaller particles with a mean particle size below 119 microm. Up to 70% of total coliforms in the larger particle size fractions were particle-associated following a UV dose (fluence) of 260 mJ.cm(-2) and would remain undetected by standard coliform enumeration techniques. Implications for urban water reuse are discussed and recommendations made for grey water treatment to ensure removal of particle-associated indicator bacteria and pathogens prior to UV disinfection.

Survival of Escherichia coli O157:H7 in waters from lakes, rivers, puddles and animal-drinking troughs

Survival of Escherichia coli O157:H7 in surface waters may increase the potential for dissipation of the organism to facilitate cycles of livestock re-infection and lead to human infection. Although previous studies have monitored survival of the organism in a range of surface waters, there is limited information on the influence of physico-chemical characteristics on persistence. Microcosms of four different surface water types (n=31) from the UK were inoculated with E. coli O157:H7 and incubated at 10 degrees C. The water types studied were: lake, puddle, river, and animal-drinking trough waters. Numbers of E. coli O157:H7 declined over time in all waters, although cells were still detected in 45% of non-sterile samples after 2 months. Persistence of E. coli O157:H7 was enhanced by water aeration and by prior sterilisation; however there was no correlation between water chemistry and mean E. coli O157:H7 die-off times or rates in any water type. Survival of the pathogen was better in lake and puddle waters than in river or drinking trough waters. Further studies are needed to establish the key water quality factors that regulate pathogen survival.

Chlorine disinfection of grey water for reuse: effect of organics and particles

Adequate disinfection of grey water prior to reuse is important to prevent the potential transmission of disease-causing microorganisms. Chlorine is a widely utilised disinfectant and as such is a leading contender for disinfection of grey water intended for reuse. This study examined the impact of organics and particles on chlorine disinfection of grey water, measured by total coliform inactivation. The efficacy of disinfection was most closely linked with particle size. Larger particles shielded total coliforms from inactivation and disinfection efficacy decreased with increasing particle size. Blending to extract particle-associated coliforms (PACs) following chlorine disinfection revealed that up to 91% of total coliforms in chlorinated grey water were particle associated. The organic concentration of grey water affected chlorine demand but did not influence the disinfection resistance of total coliforms when a free chlorine residual was maintained. Implications for urban water reuse are discussed and it is recommended that grey water treatment systems target suspended solids removal to ensure removal of PACs prior to disinfection.

Survival of Escherichia coli O157:H7 in the rhizosphere of maize grown in waste-amended soil

AIMS

To assess whether the persistence of Escherichia coli O157:H7 in soil amended with cattle slurry and ovine stomach content waste is affected by the presence of a maize rhizosphere.

METHODS AND RESULTS

Cattle slurry and ovine stomach content waste were inoculated with E. coli O157:H7. Wastes were then applied to soil cores with and without established maize plants. The pathogen survived in soil for over 5 weeks, although at significantly greater numbers in soil receiving stomach content waste in comparison to cattle slurry. Persistence of the pathogen in soil was unaffected by the presence of a rhizosphere.

CONCLUSIONS

Other factors may be more influential in regulating E. coli O157:H7 persistence in waste-amended soil than the presence or absence of a rhizosphere; however, waste type did have significant affect on the survival of E. coli O157:H7 in such soil.

SIGNIFICANCE AND IMPACT OF THE STUDY

Escherichia coli O157:H7 can be present within animal-derived organic wastes that are routinely spread on land. Introduced measures with regards to such waste disposal may decrease exposure to the organism; however, the persistence of E. coli O157:H7 for considerable periods in waste-amended soil may still pose some risk for both human and animal infection. This study has shown that whilst survival of E. coli O157:H7 in waste-amended soil is not significantly affected by the presence or absence of a maize rhizosphere; it may vary significantly with waste type. This may have implications for land and waste management.

Persistence, dissipation, and activity of Escherichia coli O157:H7 within sand and seawater environments

Runoff from agricultural land into watercourses may transport and deposit animal-derived waste contaminated with Escherichia coli O157:H7 onto beaches, which may in turn lead to human infection. To simulate contamination, freshwater mixed with cattle slurry containing E. coli O157:H7 was added to sand from three recreational beaches. The sand was then maintained in a dry state (nontidal) or subjected to a repeated seawater tidal simulation. The pathogen could still be recovered from all sands by day 5. Although survival of the pathogen did not statistically vary between sands of different origin under nontidal conditions, significant differences in numbers occurred between sands when subject to tidal simulation. In the tidal simulations, a considerable proportion of the E. coli O157:H7 rapidly dissipated from sand into the seawater. In a separate experiment, the activity of bioluminescent (lux-marked) E. coli O157:H7 cells was monitored in various mixtures of contaminated runoff water and seawater over 5 days. Pathogen activity declined with increasing seawater concentration; however, cells remained viable in all treatments over the 5-day period. The addition of nutrients to water rapidly increased pathogen activity in all treatments. Our findings highlight the resilience of E. coli O157:H7 in aquatic and marine environments.

Earthworms as vectors of Escherichia coli O157:H7 in soil and vermicomposts

Survival and movement of Escherichia coli O157:H7 in both soil and vermicompost is of concern with regards to human health. Whilst it is accepted that E. coli O157:H7 can persist for considerable periods in soils, it is not expected to survive thermophilic composting processes. However, the natural behavior of earthworms is increasingly utilized for composting (vermicomposting), and the extent to which earthworms promote the survival and dispersal of the bacterium within such systems is unknown. The faecal material produced by earthworms provides a ready supply of labile organic substrates to surrounding microbes within soil and compost, thus promoting microbial activity. Earthworms can also cause significant movement of organisms through the channels they form. Survival and dispersal of E. coli O157:H7 were monitored in contaminated soil and farmyard manure subjected to earthworm digestion over 21 days. Our findings lead to the conclusion that anecic earthworms such as Lumbricus terrestris may significantly aid vertical movement of E. coli O157 in soil, whereas epigeic earthworms such as Dendrobaena veneta significantly aid lateral movement within compost. Although the presence of earthworms in soil and compost may aid proliferation of E. coli O157 in early stages of contamination, long-term persistence of the pathogen appears to be unaffected.

Potential pitfalls in the quantitative molecular detection of Escherichia coli O157:H7 in environmental matrices

The detection sensitivity and potential interference factors of a commonly used assay based on real-time polymerase chain reaction (PCR) for Escherichia coli O157:H7 using eae gene-specific primers were assessed. Animal wastes and soil samples were spiked with known replicate quantities of a nontoxigenic strain of E. coli O157:H7 in a viable or dead state and as unprotected DNA. The detection sensitivity and accuracy of real-time PCR for E. coli O157:H7 in animal wastes and soil is low compared to enrichment culturing. Nonviable cells and unprotected DNA were shown to produce positive results in several of the environmental samples tested, leading to potential overestimates of cell numbers due to prolonged detection of nonviable cells. This demonstrates the necessity for the specific calibration of real-time PCR assays in environmental samples. The accuracy of the eae gene-based detection method was further evaluated over time in a soil system against an activity measurement, using the bioluminescent properties of an E. coli O157:H7 Tn5luxCDABE construct. The detection of significant numbers of viable but nonculturable (VBNC) as well as nonviable and possibly physically protected cells as shown over a period of 90 days further complicates the use of real-time PCR assays for quick diagnostics in environmental samples and infers that enrichment culturing is still required for the final verification of samples found positive by real-time PCR methods.

Survival of E. coli O157:H7 in organic wastes destined for land application

AIM

To determine the persistence of Escherichia coli O157 in contrasting organic wastes spread to land and to assess the potential environmental risk associated with the disposal of these wastes to land.

METHODS AND RESULTS

Twenty-seven organic wastes originating from slaughterhouses, wastewater treatment plants (raw and treated sewage), creameries and farms (bovine slurry), were inoculated with E. coli O157:H7 and incubated at 10 degrees C. Although pathogen numbers gradually declined in all the wastes, albeit at different rates even in the same waste type, E. coli O157:H7 was still viable in 77% of organic wastes tested after 2 months.

CONCLUSIONS

Long-term storage of organic wastes led to a significant and gradual decline in E. coli O157:H7 numbers. Consequently, storage may be a useful means of reducing the pathogen load of wastes destined for land application. However, in most cases, long-term storage cannot be expected to completely eliminate E. coli O157:H7 from waste.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results indicate that current legislation may be insufficient to protect the environment from E. coli O157:H7 contamination from untreated wastes spread to land.

Persistence of Escherichia coli O157 on farm surfaces under different environmental conditions

AIMS

To compare the persistence of Escherichia coli O157 on a variety of common faecally contaminated farmyard material surfaces (wood and steel) under different moisture and temperature regimes.

METHODS AND RESULTS

Samples of field-conditioned farmyard materials (galvanized steel and wood) were cut into pieces and contaminated with fresh cattle faeces inoculated with nontoxigenic E. coli O157 (strain 3704). Thereafter, they were stored at four different environmental conditions; with temperature (5 and 20 degrees C) and moisture (moist or dry) as variables. Transfer of the pathogen to hands from the surfaces was also evaluated. Escherichia coli O157 numbers declined over time on all surfaces albeit at different rates according to the sample material and environmental conditions. Persistence was greatest on moist wood samples under cooler temperatures with large population numbers remaining after 28 days. Desiccation of surfaces resulted in a more rapid decline in E. coli O157 populations under both temperature regimes. Substantial numbers of colonies may also potentially be transferred to human hands from the surfaces during brief contact.

CONCLUSIONS

When environmental conditions are favourable, E. coli O157 may persist for considerable times on a range of surfaces. However, when exposed to higher temperatures and dehydration, survival is notably decreased. Overall, bacterial persistence was significantly greater on wood samples relative to steel.

SIGNIFICANCE AND IMPACT OF THE STUDY

Escherichia coli O157 is a prevalent pathogen, common in ruminant faeces. Contact with contaminated faeces may lead to human infection, resulting in possible severe illness. Although our study used only one strain of bacteria, our findings indicates that E. coli O157 has the potential to persist for long periods of time on gates, stiles and other farmyard surfaces under a range of environmental conditions. These farmyard surfaces therefore pose a potential infection pathway particularly where there is a high risk of direct human contact (e.g. child petting zoos, open farms).

Bacteriophages--potential for application in wastewater treatment processes

Bacteriophages are viruses that infect and lyse bacteria. Interest in the ability of phages to control bacterial populations has extended from medical applications into the fields of agriculture, aquaculture and the food industry. Here, the potential application of phage techniques in wastewater treatment systems to improve effluent and sludge emissions into the environment is discussed. Phage-mediated bacterial mortality has the potential to influence treatment performance by controlling the abundance of key functional groups. Phage treatments have the potential to control environmental wastewater process problems such as: foaming in activated sludge plants; sludge dewaterability and digestibility; pathogenic bacteria; and to reduce competition between nuisance bacteria and functionally important microbial populations. Successful application of phage therapy to wastewater treatment does though require a fuller understanding of wastewater microbial community dynamics and interactions. Strategies to counter host specificity and host cell resistance must also be developed, as should safety considerations regarding pathogen emergence through transduction.

Rasch analysis of the Gross Motor Function Measure: validating the assumptions of the Rasch model to create an interval-level measure

OBJECTIVES

To describe the Rasch analysis of the Gross Motor Function Measure (GMFM-88) and to demonstrate how the assumptions of unidimensionality, sample-free measurement, and test-free measurement were validated to create an interval level measure.

DESIGN

Cross-sectional and longitudinal (12-mo) data from a prospective study of motor development in children with cerebral palsy (CP) were used for the analysis.

SETTING

Motor assessments were completed at 18 children's ambulatory rehabilitation centers in Ontario, Canada, by pediatric physical therapists trained in the use of the GMFM-88.

PARTICIPANTS

The first 537 of 682 children enrolled into a longitudinal study of motor development in children with CP. Children had a mean age of 6.43+/-2.75 years (range, 11mo-12y) with varying types and severity of CP.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

The GMFM-88.

RESULTS

The Rasch analysis, in conjunction with clinical decisions, identified 66 items from the GMFM-88 that formed a unidimensional measure (GMFM-66). Assumptions of sample-free and test-free measurement were confirmed, and a user-friendly scoring program was developed.

CONCLUSIONS

The GMFM-66 is an interval-level measure of gross motor function for children with CP; it should improve the scoring, interpretation, and overall clinical and research utility over the original GMFM.

Visual mechanisms of spatial disorientation in Alzheimer's disease

Impaired optic flow perception may contribute to the visuospatial disorientation of Alzheimer's disease (AD). We find that 36% of AD patients have elevated perceptual thresholds for left/right outward radial optic flow discrimination. This impairment is related to independent visual motion processing deficits affecting the perception of left/right motion-defined boundaries and in/out radial motion. Elevated optic flow thresholds in AD are correlated with greater difficulty in the Road Map test of visuospatial function (r = -0.5) and in on-the-road driving tests (r = -0.83). When local motion cues are removed from optic flow, subjects must rely on the global pattern of motion. This reveals global pattern perceptual deficits that affect most AD patients (85%) and some normal elderly subjects (21%). This deficit might combine with impaired local motion processing to undermine the alternative perceptual strategies for visuospatial orientation. The greater prevalence of global pattern deficits suggests that it might precede local motion processing impairments, possibly relating to the sequence of early hippocampal and later posterior cortical damage that is typical of AD.

Bioactive and immunoreactive variants of prolactin in milk and serum of lactating rats and their pups

Prolactin (PRL)-like bioactivity (in Nb2 lymphoma assay) and immunoreactivity (in radioimmunoassay (RIA)) in rat milk, maternal and neonatal sera and in neonatal rat pituitary cultures were investigated. The PRL-like bioactivity in the water-soluble fraction of rat milk was high and exceeded its immunoreactivity 5.8-, 4.0- and 2.1-fold, on days 2, 12 and 22 of lactation respectively. The elevated bioactivity to immunoreactivity (B/I) ratio of PRL in milk was not due to the presence of interleukin-2 (IL-2) in milk, since the proliferation of the CTLL-2 murine T cells, which are not sensitive to PRL, was promoted by IL-2 but not by milk. Serum levels of immunoreactive PRL were low in sera of non-weaned rat pups on days 2, 12 and 22 postpartum. Similar to milk, the B/I ratio of PRL in sera of rat pups was high and decreased with time postpartum. Pituitary glands of pups obtained on days 2, 12 and 22 secreted progressively increasing amounts of PRL in vitro; the B/I ratio ranged between 1.2 and 2.1 without a significant change. The relative concentrations of size variants in milk were not proportional to those in serum of lactating rats on day 2 postpartum as assessed by Sepharcryl S-100 HR gel permeation chromatography and Nb2 bioassay or RIA. Size variants of biologically active PRL were abundant in early milk and gradually diminished as lactation progressed: a partially resolved peak representing monomeric to dimeric PRL variants (relative molecular weights ranging between 18 k and 42 k) became progressively narrower between days 2 and 22. Biologically active and immunoreactive PRLs displayed disparate elution profiles. The elution profile of PRL in sera of neonatal rats on day 2 post-partum was different from that of maternal serum or milk. The major immunological (and possibly biological) PRL-like activity eluted as two adjacent peaks at 2.2 k and 1.5 k, raising the possibility that fragments of milk-borne PRL were absorbed from the gut after partial proteolytic degradation. In contrast with PRL, GH (which is present in rat milk only in minute concentrations) did not show heterogeneity in sera of 2-day-old rat pups in gel permeation chromatography. The present results demonstrate that the concentrations of PRL-like activity in rat milk and newborn rat serum have been grossly underestimated because levels have been measured by RIA. The high B/I ratio of PRL in milk and neonatal sera is due to the presence of PRL-related compounds.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro control of prolactin (PRL) and growth hormone secretion of neonatal rat pituitary glands: effects of ovine PRL, salmon calcitonin, endothelin-3, angiotensin II, bromocryptine and somatostatin

Bromocryptine potently decreased prolactin (PRL) secretion of pituitary glands of 2-day-old rats in vitro (up to 85% inhibition; ED50 between 0.1 and 1.0 nM) without altering the bioactivity to immunoreactivity (B/I) ratio. Bromocryptine tended to suppress growth hormone (GH) secretion although the effect did not reach statistical significance. Angiotensin-II (A-II; 1-1000 nM) stimulated PRL secretion in a dose-dependent manner without affecting secretion of GH. The B/I ratio of PRL secreted in response to A-II was increased. Somatostatin (SRIF) had no effect on PRL secretion but inhibited GH secretion in a dose-dependent manner; significant inhibition (50%) was observed at 100 nM. A 6-h exposure to ovine PRL (oPRL) in concentrations equipotent with 1.2-120 ng/ml rat PRL (rPRL) in the Nb2 bioassay had no effect on immunoreactive rPRL secretion. Salmon calcitonin (sCT) and endothelin-3 (ET-3; 0.1-100 nM) failed to inhibit secretion of PRL or GH. PRL secretion was slightly stimulated by sCT with no apparent dose-response relationship. The present findings suggest that neonatal pituitary glands do not display autoregulation of PRL secretion, and sCT and ET-3 (either endogenous or milk-derived) may not function as PRL inhibiting factors in 2-day-old pups. Thus, the receptors of PRL, sCT and ET-3 on lactotropes, or their functional coupling with inhibition of basal PRL secretion, occur at a later stage of development. The specificity of the PRL releasing factor (PRF) activity of A-II at this age is unique for established PRFs and might reflect a physiological function of PRL in osmoregulation. The increased B/I ratio of PRL secreted in response to A-II may be due to the release of specific PRL variants, and might be a sign of functional heterogeneity among lactotropes. The differential sensitivity of PRL and GH to the applied secretagogues suggests that the intracellular regulation of PRL and GH are compartmentalized in the mammosomatotrope cell.

Molecular heterogeneity of prolactin in lactating rats and their pups: biological and immunological activities in pituitary gland, serum and milk

Prolactin (PRL)-like bioactivities (in Nb2 lymphoma assay), immunoreactivities (in RIA) and B/I ratios in rat milk, maternal and neonatal pituitary glands and sera were investigated. The PRL-like bioactivity in the water-soluble fraction of rat milk (infranatant prepared by ultracentrifugation) exceeded its immunoreactivity 3-7-fold. The elevated B/I ratio was in part due to the presence of a glycosalated PRL (G-rPRL)-like material, since 5-70% of the PRL-like bioactivity was recovered from the glycosylated fraction of rat milk infranatant prepared by concanavalin-A affinity chromatography. We were unable to detect PRL-like immunoreactivity in the glycosylated fraction of rat milk, and calculated that the maximal cross-reactivity of G-rPRL in the RIA is less than 3.8%. In day 12 milk, over 80% of the G-rPRL-like bioactivity eluted from a Sephadex G-100 column as a high apparent molecular weight (Mr) substance (approximately 50 kD), while the rest eluted as a monomeric G-rPRL (24-25 kD). The PRL-like bioactivity in the nonglycosylated fraction eluted in three peaks (Mr: 50, 24 and 16 kD), while two immunoreactive peaks occurred (Mr: 24 and 8 kD). The concentration of rPRL-like immunoreactivity in rat milk increased during the first days of lactation, remained high in midlactation, and declined by the end of lactation. The PRL-like bioactivity in the nonglycosylated fraction of rat milk displayed a similar timecourse. G-rPRL-like bioactivity in rat milk, however, changes inversely, i.e. decreased between days 2 and 18 postpartum then increased by day 22. The concentration of high Mr PRL-like bioactivity in rat milk was greatly reduced by day 22 from day 2 postpartum. No PRL-like bioactivity or immunoreactivity was recovered from the IgG fraction (prepared by protein A affinity chromatography) of rat milk. The B/I ratio in day 2 maternal pituitary glands was close to 1. In neonatal pituitaries and in maternal sera, however, the B/I ratio was slightly elevated (2-3). The B/I ratio in day 2 neonatal serum was between 6 and 22, while the B/I ratio of PRL secreted by day 2 neonatal pituitary glands in vitro was 1. The present results demonstrate that the concentrations of PRL in rat milk and neonatal serum have been grossly underestimated because levels were detected by RIA. The high B/I ratio reflects the presence of PRL variants. Milk appears to be the most likely source of PRL variants in the circulation of the neonate.(ABSTRACT TRUNCATED AT 400 WORDS)

Rat milk inhibits the mitogenic response of Nb2 lymphoma cells to prolactin

Prolactin-like bioactivity in the rat milk was observed using the lactogen specific Nb2 lymphoma assay. The water soluble fraction (infranatant) of pooled milk samples obtained on days 2, 12 or 22 postpartum stimulated Nb2 cell growth in the range of 0.08-2.5 microliters/well. Higher concentrations of day-12 and day-22 (but not day-2) milk infranatant, however, decreased Nb2 proliferation in a dose-dependent fashion. [3H]-thymidine incorporation used as an indicator of cell growth was decreased by 21%, 49% and 83% at the doses of 5, 10, 20 microliters/well concentrations of day-22 milk infranatant, respectively. Milk infranatant did not reduce cell viability as assessed by Erythrosin B exclusion test. Addition of exogenous rat PRL (NIH B-6) at concentrations of ED50-ED90 did not restore the Nb2 proliferation rate decreased by milk infranatant. Saturating doses of PRL (ED100-ED400) resulted in maximal cell growth, but failed to counteract the inhibitory effect of milk infranatant. The relative molecular weight of the putative Nb2 cell inhibitor of rat milk is between 10 kDa and 30 kDa as determined by ultrafiltration and dialysis. The inhibitory activity of milk infranatant is stable at physiological pH, but is destroyed upon acidification. Thirty min of incubation at 37 degrees C enhanced but 30 min of incubation at 100 degrees C only slightly decreased the calculated total inhibitory effect of milk infranatant. These initial results indicate the presence of a water-soluble antimitogenic factor in rat milk (rMAF) which inhibits the Nb2 lymphoma cell response to prolactin in a non-competitive manner.(ABSTRACT TRUNCATED AT 250 WORDS)