Evaluation of chlorhexidine sensitization amongst healthcare workers.

BACKGROUND: Chlorhexidine is an antiseptic widely used in healthcare settings. There are increasing reports of significant hypersensitivity reactions associated with its use. Development of chlorhexidine allergy has been identified as an important occupational risk to healthcare workers (HCWs). AIMS: To evaluate the prevalence of sensitization to chlorhexidine amongst HCWs at a large tertiary hospital to assess the potential allergic safety risks associated with chlorhexidine exposure to staff. METHODS: Sensitization to chlorhexidine was evaluated by measurement of serum-specific immunoglobulin E (IgE) in samples collected from staff assessed after a sharps-injury incident and laboratory staff collected for quality assurance procedures. This test method has been shown to have high sensitivity and specificity in the diagnosis of chlorhexidine allergy. Prevalence of sensitization was additionally evaluated with reference to changes in exposure to chlorhexidine-based hand hygiene products because of infection control procedures and the coronavirus disease 2019 pandemic. RESULTS: A total of 320 samples were examined. The prevalence of positive chlorhexidine-specific IgE was 2%. Prevalence of sensitization in samples collected before and after increased chlorhexidine exposure was 1% and 3%. This did not represent a statistically significant difference. CONCLUSIONS: The prevalence figures for chlorhexidine sensitization in this study are higher than have been estimated previously for similar HCW cohorts. Increased exposure to chlorhexidine-based hand hygiene products was not demonstrated to increase sensitization in this group. Given the risk of severe reactions in sensitized individuals, this study indicates that evaluation of chlorhexidine allergy is important when investigating occupational allergy in HCWs.

Diagnostic performance of whole-body SPECT/CT in bone metastasis detection using 99mTc-labelled diphosphate: a systematic review and meta-analysis.

AIM: To evaluate the diagnostic performance of whole-body (WB) integrated single photon emission tomography (SPECT)/computed tomography (CT) in detecting bone metastasis (BM) and to investigate whether WB-SPECT/CT offered any additional benefit value compared to planar bone scintigraphy (PBS) with 99mTc-hydroxy-methylene diphosphonate or 99mTc methylene diphosphonate. MATERIALS AND METHODS: Medline, EMBASE, SCOPUS, Web of Science, and CINAHL were searched systematically up to 28 August 2019. All studies using histopathological analysis and/or follow-up imaging and clinical data as the reference standard were eligible for inclusion. RESULTS: Eleven studies (1,611 patients) were analysed. Based on patient analysis, the sensitivity, specificity, and area under the curve (AUC) of WB-SPECT/CT were 92% (92% confidence interval [CI], 89-95%), 95% (95% CI, 94-96%), and 0.9835, respectively, in the case of negative equivocal findings for BM, and 94% (95% CI, 91-96%), 94% (95% CI, 92-95%), and 0.9790, respectively, when regarded positive. On a lesion basis, these parameters were 91% (95% CI, 89-94%), 96% (95% CI, 94-97%), and 0.9906, respectively, in the case negative equivocal findings, and 92% (95% CI, 89-94%), 95% (95% CI, 94-97%), and 0.9898, respectively, when regarded positive. Comparing 1,265 patients from eight studies, higher sensitivity (92% versus 74%, p=0.04) and specificity for WB-SPECT/CT against PBS (93% versus 80%, p=0.01) in the case of positive equivocal findings; however, when regarded negative, WB-SPECT/CT demonstrated higher sensitivity (91% versus 70%, p=0.01), but no significant difference was apparent in specificity (94% versus 89%, p=0.07). CONCLUSION: Compared to PBS, WB-SPECT/CT had superior diagnostic accuracy in BM detection and exhibited a more reliable performance with less equivocal results.

IRF6 mutation screening in non-syndromic orofacial clefting: analysis of 1521 families.

Van der Woude syndrome (VWS) is an autosomal dominant malformation syndrome characterized by orofacial clefting (OFC) and lower lip pits. The clinical presentation of VWS is variable and can present as an isolated OFC, making it difficult to distinguish VWS cases from individuals with non-syndromic OFCs. About 70% of causal VWS mutations occur in IRF6, a gene that is also associated with non-syndromic OFCs. Screening for IRF6 mutations in apparently non-syndromic cases has been performed in several modestly sized cohorts with mixed results. In this study, we screened 1521 trios with presumed non-syndromic OFCs to determine the frequency of causal IRF6 mutations. We identified seven likely causal IRF6 mutations, although a posteriori review identified two misdiagnosed VWS families based on the presence of lip pits. We found no evidence for association between rare IRF6 polymorphisms and non-syndromic OFCs. We combined our results with other similar studies (totaling 2472 families) and conclude that causal IRF6 mutations are found in 0.24-0.44% of apparently non-syndromic OFC families. We suggest that clinical mutation screening for IRF6 be considered for certain family patterns such as families with mixed types of OFCs and/or autosomal dominant transmission.

The utilization of the Welfare Quality® assessment for determining laying hen condition across three housing systems.

The Welfare Quality(®) Assessment protocol for poultry ( WQA: ) provides animal-based measures allowing welfare comparisons across farms and housing systems. It was used to compare Lohmann LSL Classic White hens housed in an enriched colony ( EC: ), aviary ( AV: ), and conventional cage system ( CC: ) on a commercial farm over 2 flock cycles. Hens (n = 100/system) were scored on a variety of measures. A baseline measurement was made at placement at 19 wk of age for 1 flock, since AV hens had been reared in an aviary pullet facility ( AVP: while EC and CC hens were reared in a conventional pullet facility ( CCP: ). Hens in all systems were then assessed at 52 and 72 wk of age. Necropsies were performed on all mortalities 1 wk before and after the WQA sampling. WQAs were analyzed using Mann-Whitney U and Kruskal-Wallis tests for prevalence and Fisher's exact tests for severity. There was an effect of rearing, with AVP having shorter claws (P = 0.01), dirtier feathers (P = 0.03), and more keel abnormalities (P < 0.0001) than CCP at placement. For the hens, there were several significant housing system effects across flocks and age periods (all P ≤ 0.05). AV and EC hens had more keel abnormalities than CC hens. They also had fewer foot abnormalities than CC hens, although those in AV hens were more severe. AV hens had consistently dirtier feathers than EC and CC hens. While AV hens had the best overall feather cover, feather loss patterns suggested that loss was due to head pecking for AV, whereas in EC and CC it was due to cage abrasion. The necropsy findings and the WQA results were similar, except that the WQA failed to find enteritis at 19 wk, although it was detected in the necropsies during this sampling period. These results show that the WQA is a useful tool for detecting hen condition differences across housing systems.

Associations of chronic heart failure with outcome in acute ischaemic stroke patients who received systemic thrombolysis: analysis from VISTA.

BACKGROUND AND PURPOSE: There are concerns that systemic thrombolysis might not achieve clinically important outcome amongst chronic heart failure (CHF) patients with acute ischaemic stroke. Our aim was to investigate the relevance of CHF on the outcome of acute stroke patients who received thrombolysis. METHODS: A non-randomized cohort analysis was conducted using data obtained from the Virtual International Stroke Trials Archive. The association of outcome amongst CHF patients with thrombolysis treatment was described using the modified Rankin scale (mRS) distribution at day 90, stratified by the presence of atrial fibrillation. Dichotomized outcomes were considered as a secondary end-point. RESULTS: 5677 patients were identified, of whom 2366 (41.7%) received thombolysis. Five hundred and three (8.9%) patients had CHF, of whom 209 (41.6%) received thrombolysis. The presence of CHF was associated with a negative impact on overall stroke outcome [odds ratio (OR) 0.73 (95% confidence interval (CI) 0.62-0.87), P < 0.001]. However, thrombolysis treatment was associated with favourable functional outcome using ordinal mRS, irrespective of CHF status, after adjustment for age and baseline National Institutes of Health Stroke Scale [OR 1.44 (95% CI 1.04-2.01, P = 0.029) for CHF patients versus OR 1.50 (95% CI 1.36-1.66, P < 0.001) for non-CHF patients]. CHF patients had higher mortality at day 90 than non-CHF patients. There was no significant difference for recurrent stroke or symptomatic intracerebral haemorrhage within 7 days of the initial stroke between CHF and thrombolysis groups. CONCLUSIONS: Chronic heart failure was associated with a worse outcome with or without thrombolysis. However, acute stroke patients who received thrombolysis had more favourable outcome regardless of CHF status, compared with their untreated peers. Our findings should reassure clinicians considering systemic thrombolysis treatment in hyperacute ischaemic stroke patients with CHF.

Association of improved outcome in acute ischaemic stroke patients with atrial fibrillation who receive early antithrombotic therapy: analysis from VISTA.

BACKGROUND AND PURPOSE: Ischaemic stroke patients with atrial fibrillation (AF) are at risk of early recurrent stroke (RS). However, antithrombotics commenced at the acute stage may exacerbate haemorrhagic transformation, provoking symptomatic intracerebral haemorrhage (SICH). The relevance of antithrombotics on the patterns and outcome of the cohort was investigated. METHODS: A non-randomized cohort analysis was conducted using data obtained from VISTA (Virtual International Stroke Trials Archive). The associations of antithrombotics with the modified Rankin Scale (mRS) outcome and the occurrence of RS and SICH (each as a combined end-point of fatal and non-fatal events) at 90 days for post-stroke patients with AF were described. Dichotomized outcomes were also considered as a secondary end-point (i.e. mortality and good outcome measure at 90 days). RESULTS: In all, 1644 patients were identified; 1462 (89%) received antithrombotics, 157 (10%) had RS and 50 (3%) sustained SICH by day 90. Combined antithrombotic therapy (i.e. anticoagulants and antiplatelets), 782 (48%), was associated with favourable outcome on ordinal mRS and a significantly lower risk of RS, SICH and mortality by day 90, compared with the no antithrombotics group. The relative risk of RS and SICH appeared highest in the first 2 days post-stroke before attenuating to become constant over time. CONCLUSIONS: The risks and benefits of antithrombotics in recent stroke patients with AF appear to track together. Early introduction of anticoagulants (2-3 days post-stroke), and to a lesser extent antiplatelet agents, was associated with substantially fewer RS events over the following weeks but with no excess risk of SICH. More evidence is required to guide clinicians on this issue.

Egg Drop Syndrome 76 in a U.S. Broiler Breeder Flock.

A four-house broiler breeder farm of approximately 35-wk-old hens was diagnosed with egg drop syndrome (EDS'76) utilizing PCR and hemagglutination inhibition (HI) testing. Based on communication with local practitioners, the geographic area near where this flock was located had numerous EDS'76 cases in table egg layers at the time of diagnosis. An egg production drop was seen in the broiler breeder flock over a 7-day period, which prompted an investigation. During this investigation, a significant number of shell-less, wrinkled, and pale eggs were noted, but no increases in mortality or respiratory signs were observed. The disease and subsequent production drops spread horizontally across the farm over a 5-wk period. Production returned to approximately the breed standard egg production 4 wk after initial egg production drop. However, hatching egg utilization continued to be reduced for another 2 wk because of the number of thin-shelled eggs. A similar pattern of drop in egg production and subsequent return was observed in the other houses. No significant lesions were noted in the tissues submitted for histopathology. Differential diagnoses that could cause shell abnormalities and egg production drops were ruled out by submitting appropriate samples for diagnostic investigation. Egg drop syndrome 76 PCR was performed on shell-less eggs and EDS'76 was detected by PCR at two separate laboratories. Subsequently, serum was submitted for HI and positive results were found in each house as they showed egg production drop concurrent with shell abnormalities. At the time the flocks returned to breed standard production, EDS'76 titers were consistent with a uniformly exposed and seroconverted flock. The authors suspect that immunosuppression as pullets played a role in this flock being impacted by EDS. No other farms in the company's system were observed with production drops or shell abnormalities similar to this case.

Reporte de caso- Síndrome de baja de postura 76 en una parvada de reproductoras de pollos de engorde en los Estados Unidos. Una granja de reproductoras pesadas con cuatro casetas con aves de aproximadamente 35 semanas de edad fue diagnosticada con el síndrome de baja de postura 76 (EDS'76) mediante PCR y pruebas de inhibición de hemaglutinación. Según las comunicaciones con los profesionales locales, el área geográfica cercana a donde se encontraba esta parvada tenía numerosos casos de síndrome de baja de postura 76 en aves de postura de huevo comercial en el momento del diagnóstico. Se observó una caída en la producción de huevo en la parvada de reproductoras pesadas durante un período de siete días, lo que motivó una investigación. Durante esta investigación, se observó una cantidad significativa de huevos sin cascarón, con cascarón rugoso, y pálidos, pero no se observaron aumentos en la mortalidad ni en signos respiratorios. La enfermedad y las consiguientes caídas de producción se extendieron horizontalmente por toda la granja durante un período de cinco semanas. La producción retornó aproximadamente a la producción de huevos estándar de la estirpe de cuatro semanas después de la estirpe cuatro semanas después de la caída inicial en la producción de huevo. Sin embargo, la utilización de huevos para incubar continuó reduciéndose durante otras dos semanas debido a la cantidad de huevos de cascarón delgado. En las otras casetas se observó un patrón similar de caída en la producción de huevos y posterior retorno. No se observaron lesiones significativas en los tejidos enviados para histopatología. Se descartaron diagnósticos diferenciales que pudieran provocar anomalías en el cascarón y caídas en la producción de huevo, mediante el envío de muestras adecuadas para investigación diagnóstica. Métodos de PCR para el síndrome de baja de postura 76 se llevaron a cabo en huevos sin cascarón y el síndrome de baja de postura 76 se detectó mediante PCR en dos laboratorios diferentes. Posteriormente, se envió suero para inhibición de la hemaglutinación y se encontraron resultados positivos en cada caseta ya que mostraron una caída en la producción de huevo junto con anomalías en el cascarón. En el momento en que las parvadas volvieron a reproducir la producción estándar, los títulos de anticuerpos contra el síndrome de baja de postura 76 eran consistentes con una parvada uniformemente expuesta y con seroconversión. Los autores sospechan que la inmunosupresión en las pollitas jugó un papel en el impacto del síndrome de baja de postura en esta parvada. No se observaron otras granjas en el sistema de la compañía con caídas de producción o anomalías en el cascarón similares a este caso.

Use of paracetamol in ischaemic stroke patients: evidence from VISTA.

OBJECTIVES: Paracetamol is frequently prescribed for pain and fever control in acute stroke patients, but its effect on stroke outcome is unclear. The aim was to investigate the safety and benefit of paracetamol administration in the acute phase of ischaemic stroke. METHODS: We analysed the impact of paracetamol exposure on functional outcome at 90 days among ischaemic stroke patients registered in a clinical trials archive. We used an adjusted Cochran-Mantel-Haenszel test to test for significance (P) followed by proportional odds logistic regression analysis to estimate the odds ratios (OR) for more favourable modified Rankin Scale score. RESULTS: Data were available for 6015 patients, of whom 2435 had received paracetamol. No association of paracetamol-use with overall stroke outcome could be detected among those patients who experienced pain and/or fever (OR 1.03, 95% CI 0.86-1.20, P = 0.931). In patients without recorded pain and/or fever events and a baseline temperature below 37°C, in whom paracetamol was started within 3 days of stroke, paracetamol was associated with worse outcome (OR 0.58, 95% CI 0.47-0.72, P = <0.001). CONCLUSION: This retrospective analysis is discouraging for prophylactic use of paracetamol in acute stroke patients, but underlines the need for a sufficiently powered randomized controlled trial.

Selective depletion of myelin-reactive T cells with the anti-OX-40 antibody ameliorates autoimmune encephalomyelitis.

The OX-40 protein was selectively upregulated on encephalitogenic myelin basic protein (MBP)-specific T cells at the site of inflammation during the onset of experimental autoimmune encephalomyelitis (EAE). An OX-40 immunotoxin was used to target and eliminate MBP-specific T cells within the central nervous system without affecting peripheral T cells. When injected in vivo, the OX-40 immunotoxin bound exclusively to myelin-reactive T cells isolated from the CNS, which resulted in amelioration of EAE. Expression of the human OX-40 antigen was also found in peripheral blood of patients with acute graft-versus-host disease and the synovia of patients with rheumatoid arthritis during active disease. The unique expression of the OX-40 molecule may provide a novel therapeutic strategy for eliminating autoreactive CD4+T cells that does not require prior knowledge of the pathogenic autoantigen.

Hen welfare in different housing systems.

Egg production systems have become subject to heightened levels of scrutiny. Multiple factors such as disease, skeletal and foot health, pest and parasite load, behavior, stress, affective states, nutrition, and genetics influence the level of welfare hens experience. Although the need to evaluate the influence of these factors on welfare is recognized, research is still in the early stages. We compared conventional cages, furnished cages, noncage systems, and outdoor systems. Specific attributes of each system are shown to affect welfare, and systems that have similar attributes are affected similarly. For instance, environments in which hens are exposed to litter and soil, such as noncage and outdoor systems, provide a greater opportunity for disease and parasites. The more complex the environment, the more difficult it is to clean, and the larger the group size, the more easily disease and parasites are able to spread. Environments such as conventional cages, which limit movement, can lead to osteoporosis, but environments that have increased complexity, such as noncage systems, expose hens to an increased incidence of bone fractures. More space allows for hens to perform a greater repertoire of behaviors, although some deleterious behaviors such as cannibalism and piling, which results in smothering, can occur in large groups. Less is understood about the stress that each system imposes on the hen, but it appears that each system has its unique challenges. Selective breeding for desired traits such as improved bone strength and decreased feather pecking and cannibalism may help to improve welfare. It appears that no single housing system is ideal from a hen welfare perspective. Although environmental complexity increases behavioral opportunities, it also introduces difficulties in terms of disease and pest control. In addition, environmental complexity can create opportunities for the hens to express behaviors that may be detrimental to their welfare. As a result, any attempt to evaluate the sustainability of a switch to an alternative housing system requires careful consideration of the merits and shortcomings of each housing system.

Common Diseases of Michigan Gamebirds: A Retrospective Study.

Michigan has abundant resources for outdoor activity including upland gamebird hunting in the wild and on licensed hunting preserves. Due to the popularity of hunting, Michigan had a thriving gamebird industry before the economic downturn of 2008/2009. After the economic downturn, the number of gamebird preserves decreased. To understand the health issues faced by captive gamebird raisers while the industry was thriving, a 25-year retrospective study of gamebird submissions to the Michigan State University Veterinary Diagnostic Laboratory from 1983 through 2008 was undertaken. Although pheasants, quail, partridges, grouse, and mallard ducks were raised, pheasants greatly outnumbered all other gamebird species, both in numbers and submissions, and quail were the next most predominant species. Causes for submission included parasitic, bacterial, viral, and miscellaneous causes. Parasitic diseases were predominant, with coccidiosis being the leading diagnosis in pheasants and partridges and Capillaria spp. infestation of the crop prevailing in quail. Bacterial diseases were the next most predominant affliction, with clostridial enteritis, both necrotic and ulcerative, in quail, and a variety of bacterial diseases were found in pheasants and partridges. Rotaviral enteritis and adenovirus were the most prevalent viral diseases in pheasants, with adenovirus being the predominant viral disease in quail and paramyxovirus the most prevalent in partridges. From these findings, we conclude that gamebird submissions should be closely screened for parasitic diseases and the diagnosis confirmed at necropsy through scraping and examination of affected tissues.

Reporte de caso­Enfermedades comunes de aves de caza en Michigan: Un estudio retrospectivo. Michigan tiene abundantes recursos para la actividad al aire libre, incluida la caza de aves silvestres en tierras altas silvestres y en cotos de caza autorizados. Debido a la popularidad de la caza, Michigan tenía una próspera industria de aves de caza antes de la recesión económica de los años 2008/2009. Después de la recesión económica, el número de reservas de aves de caza disminuyó. Para comprender los problemas de salud que enfrentan los criadores de aves de caza en cautiverio mientras la industria prosperaba, se realizó un estudio retrospectivo de 25 años de los casos de diagnóstico de aves de cacería remitidos al Laboratorio de Diagnóstico Veterinario de la Universidad Estatal de Michigan desde el año 1983 hasta el 2008. Aunque se criaron faisanes, codornices, perdices, urogallos y ánades reales, los faisanes superaron en gran medida a todas las demás especies de aves de caza, tanto en número como en casos clínicos y la codorniz fue la segunda especie más predominante. Las causas de envío de casos clínicos incluyeron infecciones parasitarias, bacterianas, virales y diversas. Predominaron las enfermedades parasitarias, siendo la coccidiosis el principal diagnóstico en faisanes y perdices y la infestación en el buche por Capillaria spp. fue predominante en codornices. Las enfermedades bacterianas fueron el segundo problema más predominante, con enteritis por clostridios, tanto necrótica como ulcerativa, en codornices, y una variedad de enfermedades bacterianas se encontraron en faisanes y perdices. La enteritis por rotavirus y los adenovirus fueron las enfermedades virales más prevalentes en los faisanes, siendo el adenovirus la enfermedad viral predominante en la codorniz y el paramixovirus la más prevalente en las perdices. A partir de estos hallazgos, concluimos que las presentaciones de aves de caza deben ser examinadas de cerca para detectar enfermedades parasitarias y el diagnóstico debe confirmarse en la necropsia mediante de raspados y examen de los tejidos afectados.

Cytotoxicity of a cell-reactive immunotoxin containing ricin A chain is potentiated by an anti-immunotoxin containing ricin B chain.

In vitro killing of the human Daudi cell line by either univalent [F(ab')] or divalent (IgG) forms of rabbit anti-human Ig (RAHIg) coupled to ricin A chain can be specifically potentiated by a "piggyback" treatment with ricin B chain coupled to goat anti-rabbit Ig (GARIg). When cells are treated with univalent immunotoxin (IT) [F(ab') RAHIg-A] and then cultured, IT can be detected on the cell surface for at least 5 h, since GARIg-B can still enhance killing at this time. These results provide a strategy for in vivo use of A chain- and B chain-containing IT.

Molecular dissection of the murine antibody response to streptococcal group A carbohydrate.

Monoclonal antibodies (mAb) to streptococcal group A carbohydrate (GAC) are encoded by a minimum of two VH, four JH, four V kappa, three J kappa, one V lambda, and one J lambda gene segments. The IdX, IdI-1, and Id5 idiotypic determinants are expressed by anti-GAC mAb and are found on free kappa chains. Each pattern of these determinants is encoded by a distinct V kappa gene segment, apparently without the requirement for a particular J kappa, VH, or JH gene segment, or somatic mutation. In contrast, the binding site-associated idiotypic determinant IdI-3a does not correlate with any single V or J gene segment.

Epidemiologic investigation of Riemerella anatipestifer in a commercial duck company by serotyping and DNA fingerprinting.

A commercial duck company that raises approximately two million Pekin ducks per year experienced an outbreak of Riemerella anatipestifer (RA) on nine farms over a 1-yr period. Owing to concerns that the bacteria was being spread from farm to farm, an investigation using serotyping and DNA fingerprinting was performed. The results revealed that there were three different strains of RA involved in the outbreak. One strain was spread from one farm to six other farms, while another strain from the same farm was spread to two other farms. These findings add additional proof of the value of DNA fingerprinting in disease outbreak investigations and further support the importance of implementing biosecurity protocols to stop the spread of disease-causing organisms.

Suppression of gamma interferon production by inactivated feline leukemia virus.

Supernatants from cultures of normal feline lymphocytes stimulated with Staphylococcus enterotoxin A showed antiviral activity, characterized as a gamma-like interferon. With the addition of inactivated feline leukemia virus, markedly less interferon was produced. The reduction in interferon production was not attributable to lowered lymphocyte viability or reduced mitogenic properties of Staphylococcus enterotoxin A and appears to be a direct retroviral effect. This finding may reflect clinically relevant events that may contribute to the development of the feline or human states of acquired immunodeficiency.

Redesigning nature's poisons to create anti-tumor reagents.

Immunotoxins are conjugates of cell-reactive antibodies and toxins or their subunits. In this report, the chemistry, biology, pharmacokinetics, and anti-tumor effects of first generation immunotoxins; the preparation of improved second generation immunotoxins that display greater anti-tumor efficacy; and the role of genetic engineering in creating third-generation immunotoxins are discussed.

A suspension array immunoassay for the toxin simulant ovalbumin.

A microsphere-based suspension array (SA) system was used for the development and characterization of an immunoassay for the toxin simulant ovalbumin. Results obtained by SA immunoassay were compared with those obtained by enzyme-linked immunosorbent assay (ELISA) using the same immunoreagents. The limit of detection (LOD) for the SA ovalbumin assay was 4.9 ng/mL, compared to a LOD of 0.01 ng/mL for the ovalbumin ELISA. Although the ELISA LOD exceeded that of the SA assay, the SA assay was simple and rapid to perform, with assays being completed in half the time of the traditional ELISA. The well-to-well reproducibility (coefficient of variation (CV)) of the ELISA and the SA assay was 4.9% and 5.1%, respectively. The ELISA and SA assay plate-to-plate reproducibility was 14.8% and 6.1%, respectively. The protocols used to develop the SA assay for ovalbumin may be used as a template for development of other SA assays for toxins, bacteria, and viruses.

Real-time 3D motion tracking for small animal brain PET.

High-resolution positron emission tomography (PET) imaging of conscious, unrestrained laboratory animals presents many challenges. Some form of motion correction will normally be necessary to avoid motion artefacts in the reconstruction. The aim of the current work was to develop and evaluate a motion tracking system potentially suitable for use in small animal PET. This system is based on the commercially available stereo-optical MicronTracker S60 which we have integrated with a Siemens Focus-220 microPET scanner. We present measured performance limits of the tracker and the technical details of our implementation, including calibration and synchronization of the system. A phantom study demonstrating motion tracking and correction was also performed. The system can be calibrated with sub-millimetre accuracy, and small lightweight markers can be constructed to provide accurate 3D motion data. A marked reduction in motion artefacts was demonstrated in the phantom study. The techniques and results described here represent a step towards a practical method for rigid-body motion correction in small animal PET. There is scope to achieve further improvements in the accuracy of synchronization and pose measurements in future work.

Cloning, expression and purification of envelope proteins E1 and E2 of western equine encephalitis virus and potential use of them as antigens in immunoassays.

The genes encoding envelope proteins E1 and E2 of western equine encephalitis virus (WEEV) were respectively cloned into a prokaryotic T7 RNA polymerase-regulated expression vector. The recombinant C-terminal 6xHis-tagged WEEV E1 and E2 were expressed in bacteria as inclusion bodies that were subsequently solubilized with 8M urea, purified by immobilized metal ion affinity chromatography and finally refolded using an arginine system. The purified 6xHis-tagged proteins showed 50kDa bands as revealed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, consistent with the expected sizes of WEEV E1 and E2. The potential of the recombinant WEEV E1 and E2 as antigens for serologic tests to detect anti-WEEV antibodies for diagnosis of WEEV infection was assessed by an enzyme-linked immunosorbent assay with anti-WEEV polyclonal antibodies obtained from the mice infected with WEEV. The anti-WEEV antibodies bound the recombinant WEEV E1 and E2 in a dose dependent manner. On the contrary, antibodies against Venezuelan equine encephalitis virus with a genetic background and a disease spectrum very similar to WEEV, did not bind to the recombinant WEEV E1 and E2. Our results suggest that the recombinant WEEV E1 and E2 possess predominant antigenicity of WEEV and have the potential to be used as antigens in immunoassays to detect anti-WEEV antibodies for serological diagnosis of WEEV infection so as to eliminate the need for preparation of cell culture-derived viral antigens, which is time-consuming, expensive, laborious, tedious, and hazardous.

Kainate-induced seizures, oxidative stress and neuronal loss in aging rats.

Aging is a significant risk factor for developing epilepsy. The mechanisms underlying age-related increase in seizure susceptibility and resultant injury remain unknown. Oxidative stress is an important mechanism that contributes to diverse age-related disorders. Whether age-related increased seizure susceptibility is accompanied by increased oxidative stress remains unknown. The goal of this study was to determine if aging per se increases the susceptibility of rats to kainate-induced behavioral seizures and oxidative stress. Adult (3-4 month-old) and aging (18-19 month-old) Sprague-Dawley rats were administered a single low dose of kainate (5 mg/kg, s.c.) or saline. Behavioral seizures were monitored in all four groups for a period for a period of approximately 6 h. Oxidative stress (8-hydroxy-2'deoxyguanosine/2-deoxyguanosine; 8OHdG/2dG) was assessed 24 h following kainate injection. Stereological assessment of cell counts was performed in hippocampal tissue 7 days following kainate injection. In adult rats, administration of the low dose of kainate did not produce significant behavioral seizures, oxidative stress or cell loss. However, aging rats exhibited intense behavioral seizures consistent with status epilepticus following the low dose of kainate. In aging rats, kainate produced a significant increase in oxidative DNA damage (8OHdG/2dG) and neuronal loss in cornu ammonis regions 3 and 1 (CA3 and CA1), but not dentate gyrus compared with both age-matched controls and adult kainate-treated rats. These data suggest that the process of aging per se increases kainate-induced seizure susceptibility, oxidative stress and hippocampal pyramidal cell loss.