When stress enhances memory encoding: The beneficial effects of changing context

The effects of acute stress on memory encoding are complex, and we do not yet know all of the conditions that can determine whether stress at encoding improves or impairs memory. Recent work has found that changing contexts between encoding and stress can abolish the effects of post-encoding stress on memory, suggesting that context may play an important role in the effects of stress on memory. However, the role of context in the effects of stress on memory encoding is not yet known. We addressed this gap by examining the effects of context on the influence of acute stress on memory encoding. In a 2 × 2 experimental design, participants (N = 103) completed either a stressor (i.e., Socially Evaluated Cold Presser Test) or control task (i.e., warm water control) before completing a memory encoding task, which occurred in either in the same room as or a different room from the stressor or control task. Memory retrieval was tested for each participant within the context that they completed the encoding task. We found that, relative to nonstressed (i.e., control) participants, stressed participants who switched contexts prior to encoding showed better memory for both negative and neutral images. In contrast, when the stressor or control task occurred in the same room as memory encoding, stress had no beneficial effect on memory. These results highlight the importance of the ongoing context as a determinant of the effects of stress on memory encoding and present a challenge to current theoretical accounts of stress and memory.

OP0265-HPR IMPACT OF COVID-19 PANDEMIC ON RHEUMATOLOGY PATIENTS IN NORTHERN IRELAND – A WEB BASED CROSS-SECTIONAL SURVEY

Background:

Concern for the susceptibility of rheumatology patients to severe COVID-19 illness has been raised since the start of the pandemic. Rheumatic disease and their immunosuppressant therapies placed many patients into the ‘clinically extremely vulnerable’ group when the UK’s shielding guidance commenced on 23 March 2020. The impact of DMARDs/glucocorticoids/biologics on COVID-19 remains under investigation 1. A recent study suggested caution may be required with rituximab and sulfasalazine in COVID-19 patients 2.

Objectives:

The objective of this study is to evaluate the impact of the COVID-19 pandemic on rheumatology patients in Northern Ireland by assessing demographics, rheumatic disease, medications, disease progress, shielding advice, access to primary & tertiary care and incidence of COVID-19 infection.

Methods:

A web-based cross-sectional survey was completed in Northern Ireland. The study duration was between 23rd November 2020 and 22nd January 2021. The questionnaire included consent, demographic details, medication history, comorbidities, disease course, patient experience, shielding advice, COVID-19 illness and hospitalisation. The survey was publicised by sending 6,032 Belfast Trust NHS patients a link via SMS, posters were displayed in rheumatology departments, and links made available via NHS/Versus Arthritis social media platforms.

Results:

There were 2,615 responses and of these 2,539 had been completed and were analysed. Most respondents were aged 45+ (78.27%) and female (N=1819). Rheumatoid arthritis (41%) and psoriatic arthritis (29%) were the most common diagnoses. Just over one third (35.27%, N=896) of patients were on biological drugs. Most patients were taking methotrexate (28.04%) followed by hydroxychloroquine (15.20%) and adalimumab (12.52%). The majority (79.6%) continued treatment during the pandemic. There was evidence of disease ‘flaring’ in 30.75% of patients who had stopped treatment. Of the respondents surveyed 7.8% (N=198), tested positive for Covid-19 and of these 77.55% reported that they had received adequate shielding advice, primarily from GP or UK government sources. Only 11.11% (N=22) of those who tested positive for Covid-19 required hospital admission and 2 patients required intensive care support. Both patients requiring ICU were not on immunosuppression. Less than one third of patients testing positive for COVID-19 were on biological drugs (30.3%, N=60). Cardiovascular disease was the most prevalent comorbidity. Of the 22 patients hospitalised with COVID-19, 13.64% (N=3) were on solitary sulphasalazine therapy.

Conclusion:

The survey showed low levels of COVID-19 hospitalisation despite most patients continuing DMARD/biologic/glucocorticoid therapy. This has been replicated in other studies 1, however data continues to be gathered on the safety of some biologic drugs particularly rituximab 2. Most of our patients received clear understandable shielding guidance from a variety of sources. Many patients expressed fear of mortality, isolation and mental health issues. The survey findings indicated that stopping medication can have a negative impact on disease control.

References:

[1]Robinson PC, Yazdany J. The COVID-19 Global Rheumatology Alliance: collecting data in a pandemic. Nat Rev Rheumatol. 2020 Jun;16(6):293-294.

[2]Strangfeld A, Schäfer M, Gianfrancesco MA, et al. Factors associated with COVID-19-related death in people with rheumatic diseases: results from the COVID-19 Global Rheumatology Alliance physician-reported registry. Annals of the Rheumatic Diseases Published Online First: 27 January 2021. doi: 10.1136/annrheumdis-2020-219498

Disclosure of Interests:

None declared

AB0767 SEVERE BREAST ULCERATION IN BEHÇET’S DISEASE TREATED WITH CYCLOPHOSPHAMIDE: A CASE REPORT

Background:

Behcet’s disease is a systemic autoimmune vasculitis that typically involves mucocutaneous surfaces, the eyes and the skin with varying manifestations. Skin ulceration often secondary to pathergy is a common feature.

Objectives:

To raise awareness of breast ulceration as a clinical manifestation in Behcet’s disease.

Methods:

We report a case of complex Bechet’s disease associated with severe refractory breast ulceration successfully treated with cyclophosphamide.

Results:

A 27 year old female patient presented to the rheumatology department with a non-healing lesion on her face secondary to a cat scratch. She reported previous episodes of ulceration usually as a result of minor trauma such as IV cannulation, as well as a two year history of severe oral and genital ulceration. She had also been diagnosed with ‘colitis’ requiring iliocaecal resection two years prior to presentation. Previous treatments for her bowel included azathioprine, infliximab, adalimumab and vedolizumab. Over the next three years she developed recurrent eye involvement in the form of scleritis with ongoing oral and genital ulceration. Further treatment under our care included ustekinumab, entanercept, benepali, certolizumab and tacrolimus with background prednisolone. She then developed a small area of broken skin on her left breast which continued to extend and ulcerate despite treatment with IV steroids. Tissue biopsy showed deep focal vasculitis with intravascular thrombi. Anticoagulation was commenced and she was treated with tocilizumab IV for 3 months with no clinical improvement. Involvement extended to include 80 percent of the breast surface and the nipple self-amputated. Due to the severity and extent of the ulceration which was extremely painful and distressing, she was given 3 months of IV cyclophosphamide at a dose of 15mg/kg every 2-3 weeks. The ulceration showed rapid clinical improvement (see Figure 1).

Figure 1.

Breast ulceration before and after 3 months of cyclophosphamide treatment

Conclusion:

Involvement of the breast in systemic vasculitides (such as GPA or PAN) has been reported, although usually manifesting as a palpable mass with diagnosis on biopsy 1. Similar presentations in Behcet’s disease have been recognised 2, although much less commonly. Our case demonstrates that severe breast ulceration can be a clinical manifestation of this condition and can be refractory to usual therapies.

References:

[1]Ren J, Liu J, Su J, Zhang J, Zhao J. Systemic vasculitis involving the breast: a case report and literature review. Rheumatol Int. 2019 Aug;39(8):1447-1455

[2]Soleto MJ, Marcos L. Behçet’s disease involving the breast. Eur Radiol. 2002 Dec;12 Suppl 3:S98-S100. doi: 10.1007/s00330-002-1420-4.

Disclosure of Interests:

None declared

Newborns with C8-acylcarnitine level over the 90th centile have an increased frequency of the common MCAD 985A>G mutation

Medium chain acyl-coenzyme A dehydrogenase (MCAD) deficiency is the most commonly inherited defect of fatty acid oxidation. This autosomal recessive disorder is characterized by the tendency to become profoundly hypoglycaemic under fasting stress conditions, leading to lethargy, coma, brain injury and/or death. The most common mutation resulting in MCAD deficiency ascertained through individuals of northern European descent presenting with clinical symptoms is a single base-pair change (985A>G) that accounts for up to 90% of these abnormal alleles. In the general Nova Scotia population, which comprises largely individuals of northern European descent, this mutation is present at a frequency of 1 in 68. A recently implemented newborn screening programme for MCAD deficiency uses tandem mass spectrometry (MS/MS) to analyse blood spots from newborns for C8-acylcarnitine. After reviewing initial data from this newborn screening programme, we hypothesized that there was an unexpectedly high frequency of individuals with an MCAD 985A>G mutation and C8-acylcarnitine levels at the upper end of the normal range. A sample representing the upper 90th centile was screened for the presence of the 985A>Gmutation and 61 heterozygotes were identified, establishing a high frequency (1/10) of this 985A>G mutation in this selected population. We have demonstrated a relationship between heterozygosity for 985A>G and C8-acylcarnitine levels. These results contribute to the interpretation of C8-acylcarnitine levels and the establishment of a more clinically relevant screening cut-off point.

Predictive, pre-natal and diagnostic genetic testing for Huntington's disease: the experience in Canada from 1987 to 2000

Predictive and pre-natal testing for Huntington's Disease (HD) has been available since 1987. Initially this was offered by linkage analysis, which was surpassed by the advent of the direct mutation test for HD in 1993. Direct mutation analysis provided an accurate test that not only enhanced predictive and pre-natal testing, but also permitted the diagnostic testing of symptomatic individuals. The objective of this study was to investigate the uptake, utilization, and outcome of predictive, pre-natal and diagnostic testing in Canada from 1987 to April 1, 2000. A retrospective design was used; all Canadian medical genetics centres and their affiliated laboratories offering genetic testing for HD were invited to participate. A total of 15 of 22 centres (68.2%), currently offering or ever having offered genetic testing for HD, responded, providing data on test results, demographics, and clinical history. A total of 1061 predictive tests, 15 pre-natal tests, and 626 diagnostic tests were performed. The uptake for predictive testing was approximately 18% of the estimated at-risk Canadian population, ranging from 12.5% in the Maritimes to 20.7% in British Columbia. There appears to have been a decline in the rate of testing in recent years. Of the predictive tests, 45.0% of individuals were found to have an increased risk, and a preponderance of females (60.2%) sought testing. A greater proportion of those at < or = 25% risk sought predictive testing once direct CAG mutation analysis had become available (10.9% after mutation analysis vs 4.7% before mutation analysis, p = 0.0077). Very few pre-natal tests were requested. Of the 15 pre-natal tests, 12 had an increased risk, resulting in termination of pregnancy in all but one. Diagnostic testing identified 68.5% of individuals to be positive by mutation analysis, while 31.5% of those with HD-like symptoms were not found to have the HD mutation. The positive diagnostic tests included 24.5% of individuals with no known prior family history of HD.

Influence of whole barley and grit on live performance and health of turkey toms

Live performance to 96 d was compared for 1,584 turkey toms reared on diets containing four levels of whole barley and two levels of insoluble grit (0 or 9 g/bird per wk). Nutrient specifications for all diets were similar. The six dietary treatments were 1) 0% whole barley plus grit, 2) Treatment 1 minus grit, 3) grit plus 5% whole barley at 0 d increasing to 35% by 19 d, 4) grit plus 5% whole barley at 0 d increasing to 50% by 19 d, 5) Treatment 4 minus grit, and 6) grit plus 5% whole barley at 19 d increasing to 50% by 40 d. The concentrate blended with the whole barley was fed as crumbles or pellets. Nutrients were not diluted. Compared to the control treatments, feeding 35% or more whole barley temporarily reduced weight gain and increased feed:gain prior to 68 d. Cumulative weight gain was reduced in Treatments 3 and 5 compared to treatments in which no barley was fed. Cumulative feed:gain was increased in Treatment 5 compared to Treatments 2 and 3. Total mortality and leg and skeletal problems were reduced in treatments where whole grain slowed early growth rate. Feeding grit had no effect on the live performance of birds fed similar levels of whole barley. In treatments in which whole barley was introduced at 0 d, gizzard pH was decreased at 18 d, and gizzard weight was increased at 32 d. Jejunal viscosity was unaffected by dietary treatment.

Feeding broiler chickens wheat and barley diets containing whole, ground and pelleted grain

The effect of grain form (whole, mash, or pelleted) on the live performance of broiler chickens was determined. In the first trial, six regimens compared the feeding of whole wheat: 1) 0% of diet for the whole trial (0 to 48 d); 2) 5% at 6 d, 20% at 13 d, 35% at 27 d; 3) 5% at 6 d, 35% at 13 d, 50% at 27 d; 4) 5% at 0 d, 20% at 6 d, 35% at 13 d, 50% at 27 d; 5) 5% at 6 d, 50% at 13 d, 65% at 27 d; and 6) 5% at 0 d, 20% at 6 d, 50% at 13 d, 65% at 27d. Each feeding regimen was replicated with steam-pelleted and mash supplements. None of the feed was diluted. The second trial was similar, except that whole barley was fed instead of whole wheat. Feeding mash supplements slowed growth at all ages and lowered mortality caused by sudden death syndrome and ascites plus right heart failure. Cumulative feed:gain was increased by feeding mash supplements in Trial 1. Total weight gain was unaffected by feeding whole wheat but was decreased by most levels of whole barley. Whole-grain diets increased cumulative feed:gain. Feeding whole wheat decreased skeletal problems. Whole-grain diets increased gizzard size but did not alter carcass yield. Feeding whole-grain and mash supplements caused at least a temporary loss in growth rate and feed efficiency but in some cases improved bird health.

Histopathologic and bacteriologic evaluations of cellulitis detected in legs and caudal abdominal regions of turkeys

The objective of this study was to identify the causative agent of cellulitis in turkeys. Eighteen flocks from nine producers were sampled at the local processing plant, and 37 birds with cellulitis on legs or caudal thoracic area were obtained. None of the 37 birds with cellulitis had lesions in other organs. On gross examination, lesions were categorized into two groups: cellulitis with unopened skin lesions (type a) and cellulitis with opened skin lesions (type b). Histopathologically, cellulitis with unopened skin lesions had dermal necrosis with underlying fibrin and inflammatory exudate but cellulitis with open skin lesions had chronic granulomatous/granulation tissue-type reaction associated with foreign material. A complete bacteriologic study was conducted on 25 of 37 birds. Bacteria were isolated from 12 of the 25 birds with cellulitis lesions. No aerobic, microaerophilic, or anaerobic bacteria were isolated from the remaining 13 birds with cellulitis lesions. Escherichia coli was isolated in low numbers in mixed cultures with Proteus mirabilis, Lactobacillus spp., Klebsiella spp., and Staphylococcus spp. in 9 of 12 lesions. The remaining few cases yielded P. mirabilis in pure culture or in mixed culture with Pseudomonas aeruginosa. Types a and b cellulitis lesions in turkeys could be associated with primary contact dermatitis and skin abrasions, respectively. Their occurrence is likely associated with different management practices.

Noise reduction in oncology FDG PET images by iterative reconstruction: a quantitative assessment

Tumor detection depends on the contrast between tumor activity and background activity and on the image noise in these 2 regions. The lower the image noise, the easier the tumor detection. Tumor activity contrast is determined by physiology. Noise, however, is affected by many factors, including the choice of reconstruction algorithm. Previous simulation and phantom measurements indicated that the ordered-subset expectation maximization (OSEM) algorithm may produce less noisy images than does the usual filtered backprojection (FBP) method, at equivalent resolution. To see if this prediction would hold in actual clinical situations, we quantified noise in clinical images reconstructed with both OSEM and FBP.

METHODS

Three patients (2 with colon cancer, 1 with breast cancer) were imaged with FDG PET using a "gated replicate" technique that permitted accurate measurement of noise at each pixel. Each static image was acquired as a gated image sequence, using a pulse generator with a 1-s period, yielding 40 replicate images over the 10- to 15-min imaging time. The images were or were not precorrected for attenuation and were reconstructed with both FBP and OSEM at comparable resolution. From these data, images of pixel mean, SD, and signal-to-noise ratio (S/N) could be produced, reflecting only noise caused by the statistical fluctuations in the emission process.

RESULTS

Noise did not vary greatly over each FBP image, even when image intensity varied greatly from one region to the next, causing S/N to be worse in low-activity regions than in high-activity regions. In contrast, OSEM had high noise in hot regions and low noise in cold regions. OSEM had a much better S/N than did FBP in cold regions of the image, such as the lungs (in the attenuation-corrected images), where improvements in S/N averaged 160%. Improvements with OSEM were less dramatic in hotter areas such as the liver (averaging 25% improvement in the attenuation-corrected images). In very hot tumors, FBP actually produced higher S/Ns than did OSEM.

CONCLUSION

We conclude that OSEM reconstruction can significantly reduce image noise, especially in relatively low-count regions. OSEM reconstruction failed to improve S/N in very hot tumors, in which S/N may already be adequate for tumor detection.

Noninvasive estimation of the aorta input function for measurement of tumor blood flow with

Quantitative measurement of tumor blood flow with [15O]water can be used to evaluate the effects of tumor treatment over time. Since quantitative flow measurements require an input function, we developed the profile fitting method (PFM) to measure the input function from positron emission tomography images of the aorta. First, a [11C]CO scan was acquired and the aorta region was analyzed. The aorta diameter was determined by fitting the image data with a model that includes scanner resolution, the measured venous blood radioactivity concentration, and the spillover of counts from the background. The diameter was used in subsequent fitting of [15O]water dynamic images to estimate the aorta and background radioactivity concentrations. Phantom experiments were performed to test the model. Image quantification biases (up to 15%) were found for small objects, particularly for those in a large elliptical phantom. However, the bias in the PFM concentration estimates was much smaller (2%-6%). A simulation study showed that PFM had less bias and/or variability in flow parameter estimates than an ROI method. PFM was applied to human [11C]CO and [15O]water dynamic studies with left ventricle input functions used as the gold standard. PFM parameter estimates had higher variability than found in the simulation but with minimal bias. These studies suggest that PFM is a promising technique for the noninvasive measurement of the aorta [15O]water input function.

Phenotypic and genotypic characterization of virulence factors of Escherichia coli isolated from broiler chickens with simultaneous occurrence of cellulitis and other colibacillosis lesions

The objective of this study was to characterize virulence factors of Escherichia coli isolates from broilers with simultaneous occurrence of cellulitis and other colibacillosis lesions. Thirty flocks were sampled and 237 birds with cellulitis were examined. Eighty-two (34.6%) of 237 birds condemned for cellulitis had gross lesions in the heart, air sacs, joints, or liver. In 58 chickens, E. coli was isolated from both the cellulitis and other lesions of colibacillosis, and 18.9% of the E. coli isolates from the 2 types of lesions belonged to the same O group. Escherichia coli of serogroups O78, O1, and O2 predominated. Isolates of the same serogroup that were derived from different lesions in the same birds had similar patterns of biotype, aerobactin production, serum sensitivity profile, antibiotic sensitivity, and K1 capsule production. Escherichia coli derived from cellulitis lesions produced virulence factors similar to those found in E. coli isolated from other colibacillosis lesions in poultry.

Self-sealing sclerotomies for sutureless pars plana vitrectomy

OBJECTIVE

To determine the efficacy of self-sealing pars plana sclerotomies for vitrectomy and to identify complications associated with this new technique.

METHOD

There were 150 self-sealing sclerotomies performed in 50 patients undergoing pars plana vitrectomy between October 1996 and March 1998.

RESULTS

Of the 150 sclerotomies, 115 (76.6%) did not require suturing while 35 (23.3%) were closed with one radial 7.0 vicryl suture. The scleral tunnel incisions ensured minimal loss of intraocular fluids during instrument exchange and scleral plugs were not required to avoid ocular hypotony during scleral indentation. Distortion of scleral flap incisions requiring a suture were commonly seen in procedures using multiple instrumentations and extensive explants.

CONCLUSIONS

Sutureless sclerotomies are simple to perform, save operative time, and reduce the risk of peroperative hypotony following removal of instruments or the infusion cannula. The technique reduces postoperative inflammation, suture-related problems including astigmatism, and allows more rapid rehabilitation.

Can I drive after those drops, doctor?

PURPOSE

To document the experience of patients driving after drops to dilate the pupils. There are no documented guidelines on driving after pupillary dilatation. This is a study of patients who drove a car after attending the eye casualty for an ocular examination during which their pupils were dilated.

METHODS

Thirty patients were identified who felt confident to drive after their pupils were dilated. Distant visual acuities, colour vision and confrontation visual fields were assessed before and after pupillary dilatation with 2.5% phenylephrine and 1% tropicamide. These patients met the legal requirements for driving after pupillary dilatation. The patients completed a questionnaire that recorded their subjective experiences of driving while their pupils were dilated.

RESULTS

The mean age of the patients was 51.9 +/- 19.7 years (range 20-73 years). Twenty-seven of the 30 patients undertook the journey on familiar roads, and 14 of 30 wore spectacles. The mean spherical equivalent was +2.00 dioptre sphere for distance and a mean additional spherical equivalent of 1.75 dioptre sphere for near. Twenty patients experienced glare, which was severe enough to cause difficulty driving in three cases. Two of these patients drove in sunny weather conditions and one in light (not sunny) weather. Six patients had difficulty with road signs, two had difficulty judging distances and one reported difficulty with traffic lights.

CONCLUSIONS

Dilating the pupils did not reduce distance visual acuity. However, it would seem appropriate to warn patients of the problems associated with glare and, if driving is their only option for transport home, recommend that they allow sufficient time to adapt to a dilated pupillary state, drive only on familiar roads and avoid driving in sunny weather.

An automatic classification technique for attenuation correction in positron emission tomography

In this paper a clustering technique is proposed for attenuation correction (AC) in positron emission tomography (PET). The method is unsupervised and adaptive with respect to counting statistics in the transmission (TR) images. The technique allows the classification of pre- or post-injection TR images into main tissue components in terms of attenuation coefficients. The classified TR images are then forward projected to generate new TR sinograms to be used for AC in the reconstruction of the corresponding emission (EM) data. The technique has been tested on phantoms and clinical data of brain, heart and whole-body PET studies. The method allows: (a) reduction of noise propagation from TR into EM images, (b) reduction of TR scanning to a few minutes (3 min) with maintenance of the quantitative accuracy (within 6%) of longer acquisition scans (15-20 min), (c) reduction of the radiation dose to the patient, (d) performance of quantitative whole-body studies.

Inflammation of the bronchi in broiler chickens, associated with barn dust and the influence of barn temperature

Broiler chickens were raised in separate rooms kept at temperatures of either 27 C or 16 C from 28 through 39 days of age. At the high temperature mouth breathing was recorded, but it was absent at the lower temperature. The number of dust particles in the air was greater in the warm rooms. More than 50% of the chickens in warm rooms had microscopic lesions in the bronchi of their lungs, whereas fewer than 5% of chickens in cold rooms had such lesions. Large dust particles were visible in some of the lesions. It was postulated that the increased incidence of lung lesions in chickens from warm rooms was due to mouth breathing rather than the higher dust levels in the air of these rooms.

Evaluation of pre- and post-reconstruction count-dependent Metz filters for brain PET studies

In this study we evaluated pre- (PR-R) and post-reconstruction (PO-R) count-dependent Metz filters for PET brain studies in order to increase signal-to-noise ratio. A set of studies using a 3D Hoffman brain phantom was performed at various count levels, and a reference image set was created from extremely high count images. Several combinations of PR-R and PO-R filtering were considered to find the optimal means of processing, including: Hann filter alone; PR-R Metz filter without or with a PO-R low pass filter; and PO-R Metz filter without or with a PR-R low pass filter. A formula was established to correlate the optimal PO-R Metz filter order with the net counts. Resolution [full width at half-maximum (FWHM) and fill width at tenth maximum (FWTM)], normalized residual mean square differences (NRMSD) between the ideal and the processed images, noise reduction and contrast were used as parameters for the evaluation of the different filter combinations. Resolution is decreased by all filter combinations that can effectively control noise; however, FWTM increases less than FWHM. NRMSD indicates that the use of Hann and (optimal) PO-R Metz filter is the most powerful combination from among those tested. A close correlation (r = 0.969) was found between the net counts and the optimal order of the PO-R Metz filter. At the count levels of clinical studies the PO-R Metz filter was found to control noise much more effectively and enhance the contrast when compared to the routinely used Hann filter alone, and produced images of better quality.

Isolation of Escherichia coli from cellulitis and other lesions of the same bird in broilers at slaughter

Cellulitis results in substantial losses to the broiler industry due to condemnations at slaughter. This study was conducted to clarify the association between Escherichia coli isolated from cellulitis and other lesions caused by E. coli in individual birds. Fourteen flocks were sampled and 118 birds with cellulitis were examined. Escherichia coli was isolated from all but 2 of the cellulitis lesions, and serogroups O78, O1, and O2 predominated. Thirty-six birds had at least 1 other lesion in addition to the cellulitis lesion. Isolation of E. coli from cellulitis and other lesions occurred in 7 of the 14 flocks. Escherichia coli of the same serogroup were isolated from cellulitis and other lesions in some birds, suggesting that a single E. coli may sometimes be responsible for both types of lesions.

A study of electrocardiographic patterns in a population of commercial broiler chickens

A study was completed to characterize the electrocardiographic (ECG) patterns of male broiler chickens. Data were collected from 300 commercial broilers. ECG readings were collected from all birds between 12 and 15 days of age and then twice more at 10-day intervals. The measurements. included heart rate and rhythm, QRS complex duration, amplitude and mean electrical axis (MEA), incidence of ascites and incidence of sudden death syndrome (SDS). Eight birds died from SDS and 4 birds died from ascites. Twelve birds were condemned for ascites at the processing plant. The overall population heart rate declined with age. Birds that died of SDS had a higher heart rate, whereas those that developed ascites had a lower heart rate than the remainder of the population. The normal MEA was found to be between 0 degree and 180 degrees. On average 30% of birds showed left or right QRS axis deviation, and this pattern was observed in 14 of the 16 birds that developed ascites. Several types of cardiac arrhythmias were observed, the most common being premature ventricular contractions (PVC). The incidence of PVC increased with age, ranging from 1% at 12-15 days of age to 8.9% at 32-35 days of age. QRS axis deviation was present in 5 SDS birds. It is concluded that some 30% of the broiler flock tested was at risk of developing heart failure or heart-related disease.

Experimental reproduction of Escherichia coli cellulitis and septicemia in broiler chickens

Experimental reproduction of avian cellulitis was conducted by subcutaneous inoculation of 25-day-old broiler chickens with a field isolate of serogroup O78 Escherichia coli. Development of the cellulitis lesion occurred as early as 24 h post-infection. Reproduction of cellulitis occurred in 98% of inoculated birds, and E. coli was isolated from > 75% of cellulitis lesions. In addition to cellulitis, other lesions, including pericarditis, airsacculitis, osteomyelitis, arthritis, and perihepatitis, occurred in > 80% of birds inoculated with E. coli. Bacteremia occurred as early as 6 h post-infection and dramatically declined by 5 days post-infection. Seventeen of 59 (29%) birds inoculated with E. coli developed a fatal infection between 1 and 6 days post-infection, and bacteria were isolated from lesions in 98% birds. In contrast, E. coli was not isolated from lesions in birds that survived until days 7-14 post-infection. Birds that survived with cellulitis and other lesions until day 14 post-infection had a significantly lower body weight compared with the control group. This avian model of cellulitis and other lesions will be useful for studying the development of vaccination strategies for E. coli in broilers.

Escherichia coli cellulitis in broiler chickens: clonal relationships among strains and analysis of virulence-associated factors of isolates from diseased birds

Thirty-nine Escherichia coli isolates from broiler chickens with cellulitis were serotyped and analyzed for clonal relationships by multilocus enzyme electrophoresis. The isolates were further characterized with respect to hemagglutination (HA); serum resistance; antibiotic susceptibility; production of aerobactin, colicin V, and hemolysin; expression of K1 or K5 capsule; sensitivity to cloacin DF13 after treatment with diphenylamine; expression of iron-regulated outer membrane proteins; and virulence in 1-day-old chickens. In addition, the isolates were examined for the presence of DNA sequences related to F1A (fim) and P (pap) fimbriae, aerobactin synthesis (iuc) and transport (iut), hemolysin operon hly, and TraT lipoprotein-induced serum resistance (traT). Only 38.4% of the isolates were typeable with standard O antisera, and of these, serogroups O25 and O78 were the most frequently observed. Multilocus enzyme electrophoresis, based on 20 enzymes, resolved 17 electrophoretic types, forming seven clusters. Isolates from four of these clusters fell into E. coli clone complexes that have been previously reported to be commonly associated with avian colibacillosis. All isolates expressed two to five iron-regulated outer membrane proteins, were resistant to serum and cloacin DF13, and possessed DNA sequences homologous to fim and iuc/iut. Most isolates (72%) were positive for traT, and a majority produced colicin V and aerobactin (92 and 82%, respectively). Assays for the presence of fim and pap DNA sequences, for HA, and for virulence gave variable results but suggest that cellulitis isolates may express F1A and/or other mannose-resistant HA fimbriae different from P and may be virulent in 1-day-old chickens. Our results support the hypothesis that cellulitis in broilers in many cases is caused by E. coli clones identical to other pathogenic avian E. coli strains. Certain clones may be specific to cellulitis, because 25% of the isolates tested belong to clusters not related to known clone complexes.

Live performance and health of broiler chickens fed diets diluted with whole or crumbled wheat

Broiler chicken diets were diluted with three levels of whole wheat and two levels of crumbled wheat to determine how feeding whole grain and diluting feed with wheat would alter the performance of male and female broilers. Grit was not used. The amount of extra wheat added increased from 5% at 11 d of age to a maximum level of 30% at 31 d of age. Body weight at 41 d of age averaged 2.130 kg for pullets and 2.422 kg for cockerels and was unaffected by diluting with wheat, in whole or crumbled form. Total mortality and cause of mortality were similarly unaffected by dilution and form of wheat. The feed:gain ratio from 11 to 41 d of age was increased significantly for cockerels from 1.75 at zero dilution to 1.84 at maximum dilution. Dilution did not affect the feed conversion of pullets and form did not influence the feed conversion of either sex. Dilution of broiler rations may be profitable because of the limited effect on bird performance. Pelleting all the wheat in poultry rations is unnecessary because bird performance is unaffected by feeding up to 30% whole grain in the finisher diets. Key words: Broiler chickens, whole wheat, pelleting

Esophagitis due to a herpesvirus associated with mortality in a psittacine aviary

In a disease outbreak at a psittacine aviary, eight Pionus sp. and Amazon parrots became sick. Three of four Amazon parrots died with severe esophagitis, and epithelial intranuclear inclusion bodies containing herpesvirus were prominent. Focal liver necrosis with rare hepatocyte intranuclear inclusion bodies were found in two of the dead Amazon parrots.

The approximate inverse and conjugate gradient: non-symmetrical algorithms for fast attenuation correction in SPECT

Hybrid methods have been known for a long time as very efficient algorithms for attenuation correction in single-photon emission computed tomography, but only recently have efforts been made to formulate them with more rigorous mathematics. This has allowed us to explain their efficiency in terms of approximate inversion, and to establish a convergence condition. The present study focuses on the convergence problem and emphasizes the question of symmetry. Hybrid method operators are not symmetrical; therefore the convergence condition is not easily verified. New schemes based on a modified conjugate gradient method are presented. Convergence is proved and performances are shown to be at least as good as the standard hybrid schemes on perfect and noisy simulated data.

Effect of infection with hemorrhagic enteritis virus on susceptibility of turkeys to Escherichia coli

The present study was designed to investigate hemorrhagic enteritis virus (HEV) as a predisposing factor influencing the susceptibility of young turkeys to Escherichia coli infections. In addition, the pathologic changes caused by administration of E. coli by various routes were compared. Following oral infection with HEV, groups of turkeys were inoculated with various doses of pathogenic E. coli by intravenous (IV), intra-air sac (IA), or intratracheal (IT) routes. A synergistic effect was observed in birds that were exposed to a combined HEV-E. coli challenge, resulting in higher mortality than that caused by either pathogen alone. This synergy was more evident when the bacteria were administered by the IT route than when it was administered by the two other routes. Turkeys infected with HEV and then inoculated IT with E. coli O78 had higher mortality (61%) and higher occurrence of gross body lesions (74%) than birds given E. coli alone (0% mortality and 16% gross lesions). After E. coli inoculation by the IA and IT routes, lesions observed were mainly pericarditis, perihepatitis, lung and air-sac lesions, splenic enlargement, and occasional arthritis. The incidence of lesions was affected by HEV exposure. In contrast, IV inoculation with E. coli O78 usually resulted in arthritis, and its incidence was independent of previous HEV exposure. The synergistic effect between HEV and E. coli administered IT can be used as a challenge model for testing E. coli vaccines.

Effect of lighting treatment on the productivity, health, behavior and sexual maturity of heavy male turkeys

1. Turkey poults (1620) were used to compare the effects of three lighting programmes on heavy strain males reared to 188 d: constant light (24L:0D, CON); increasing light (6L:18D at 7 d gradually increasing to 20L:4D by 63 d, INC); a pattern identical to INC followed by a decrease in daylength from 84 d to 10L:14D at 112 d (DID). 2. Lighting affected growth pattern but had no effect on body weight at 118 d or overall food to gain ratio. 3. Both INC and DID lighting reduced overall mortality in comparison to CON light primarily because of a reduction in the incidence of skeletal disease and spontaneous cardiomyopathy. INC and DID lighting increased the incidence of cannibalism. 4. Turkeys given INC or DID lighting had a superior ability to walk in comparison to those birds given CON light. 5. INC and DID males stood, ate and drank more frequently, and sat less often than CON turkeys during behavioural observation. 6. There were no lighting effects on carcase composition except that INC and DID birds had heavier keel bones. The ultimate force per cm2 (stress) required to break femora was greater for turkeys given INC and DID lighting (P = 0.065). 7. Plasma testosterone concentrations at 117 d were 272.5, 115.2 and 29.5 pg/ml for turkeys given CON, INC and DID lighting, respectively (P = 0.072). Testosterone concentration was not related to growth rate.

A retrospective study of circovirus infection in pigeons: nine cases (1986-1993)

Circovirus infections were diagnosed in 12 pigeons from the United States 4 pigeons from Australia, and 1 pigeon from Canada (1986-1993). Circovirus was identified by electron microscopic examination of basophilic botryoid cytoplasmic inclusions that had a histologic appearance similar to that of psittacine beak and feather disease virus inclusions. Inclusions were seen in splenic, bursal, gut-associated, and bronchus-associated lymphoid tissue macrophages and in bursal epithelial cells. Inclusions were composed of paracrystalline arrays of tightly packed, nonenveloped icosahedral virions 14-17 nm in diameter. Histologic changes in the spleens ranged from lymphofollicular hyperplasia with mild discrete lymphocellular necrosis to lymphoid depletion and diffuse histiocytosis. Lesions in the bursa of Fabricius ranged from mild lymphocellular necrosis to severe cystic bursal atrophy. Remaining histologic findings coincided with concurrent bacterial, viral, fungal, and parasitic infections. Immunoperoxidase staining and DNA in situ hybridization demonstrated that pigeon circovirus is distinct from psittacine beak and feather disease virus; however both viruses apparently share some homologous DNA sequences. Clinical and diagnostic findings indicate that pigeon circovirus may be similar to psittacine beak and feather disease virus with respect to acquired immunodeficiency and subsequent multiple secondary infections.

Correction of attenuation in SPECT with an attenuation coefficient map: a new method

Attenuation coefficient (mu) maps, measured from transmission scan, are now becoming available. A simple method of attenuation correction is needed for routine implementation, however. Significant attenuation compensation can be mathematically obtained by dividing each actual pixel value of emission projections by the average of all the attenuation factors [exp (-sigma mu)] of all voxels along the same projection ray. This simple method, compatible with filtered back projection algorithms, was tested on simulations of cardiac and cerebral transaxial images on a Vax computer using the RECLBL library. In the models, the different structures received different activity and mu values. Three types of emission projections were generated: the ideal projections obtained by summation of the activity along each projection ray, the corresponding attenuated projections, and the projections corrected for attenuation. Comparison of projections on a pixel by pixel basis showed differences of less than 20% between the corrected and ideal projections. After reconstruction, both absolute and relative quantification were greatly improved by the correction of attenuation. Further validation of the method is in progress with actual patient data.

The influence of diet on necrotic enteritis in broiler chickens

Necrotic enteritis was reproduced in broiler chickens by mixing cultures of Clostridium perfringens in the feed. Mortality due to necrotic enteritis was higher among chickens fed rations based on wheat, rye, barley, and oat groats than among chickens fed corn-based rations. Addition of pentosanase to a wheat-based diet did not affect the level of mortality due to necrotic enteritis. Addition of pectin and guar gum to different rations severely reduced growth rate and eliminated necrotic enteritis from test birds. Addition of glucose to a corn-based diet caused a small increase in mortality due to necrotic enteritis.

Effects of increasing photoperiod length and anticoccidials on performance and health of roaster chickens

Male broiler chickens were raised to 63 days of age under different lighting and anticoccidial treatments. A constant-light program was compared with two interrupted and increasing-light programs in which the photoperiod length was 6 hours between 7 and 14 days of age and then increased gradually to continual light by 49 days of age in the first program and more gradually to 18 hours by 49 days of age in the second program. By 63 days of age, the increasing-light programs significantly increased body-weight gain and decreased feed/grain ratio, but not significantly. The increasing-light programs reduced the incidence of skeletal disease from 7.56% to 2.88% in the first program and to 3.53% in the second program, reduced the incidence of acute death syndrome from 5.94% to 3.37% in the first program and to 4.65% in the second program, and reduced total mortality from 18.81% to 11.71% in the first program and to 11.38% in the second program. The lighting programs had no effect on the incidence of ascites and right heart failure, the ratio of right ventricular weight to total ventricular weight, the incidence of clinical and subclinical tibial dyschondroplasia, and the number of cartilaginous and osseous nodules in the lungs. The anticoccidials compared were monensin and amprolium/ethopabate, from 0 to 35 days of age. These treatments had no significant direct effects on any of the parameters measured.

Viral tracheitis in goslings in Saskatchewan

Up to 12% mortality occurred in goslings between 4 and 11 days of age in two sequential hatches from a single breeder flock. Respiratory signs were noted before the birds died. The most consistent necropsy finding was a white opaque plug of fibrin and cellular debris in the trachea. The tracheal epithelium was hyperplastic and metaplastic with intranuclear inclusion bodies present in superficial cells. An adenovirus was isolated in both chicken and goose embryo liver cells.

Inflammation of the nasal gland in domestic turkeys

A prominent swelling above the eye of range-reared tom turkeys was found to be due to severe inflammation and hyperplasia of the nasal or salt gland. The incidence of affected turkeys was sporadic, and no mortality or other lesions were associated with the condition.

Effects of increasing photoperiod length on performance and health of broiler chickens

1. Broiler performance and health were compared from 0 to 42 d for lighting programmes consisting of near-continuous light 23L:1D (23L), a lighting programme where photoperiod gradually increased from 6 to 23 h between days 4 and 35 (INC) or an increasing-lighting programme with 1 h of light mid-way through the scotophase (INC + 1). 2. The increasing lighting programmes reduced growth rate and increased gain:food ratio from 0 to 21 d; INC + 1 growth rate was intermediate to the 23 L and INC treatments. From 0 to 42 d there were no differences in growth rate or gain:food ratio among lighting treatments. Males grew faster, ate more food and converted food more efficiently than females. 3. The increasing-lighting programmes (INC and INC + 1) resulted in less skeletal disease than the 23L control. The incidence of sudden death syndrome (SDS) and mortality other than SDS were numerically lower for the increasing lighting treatments. More males died as a result of SDS and were affected by skeletal defects than females. 4. In terms of health, increasing lighting programmes were superior to near-continuous light for broiler chickens.

A study of hepatic lesions in broiler chickens at processing plants in Saskatchewan

A detailed descriptive study was done on broiler chickens with abnormal livers found at processing. Two syndromes were evident: those birds with enlarged, pale, firm livers, designated hepatosis, with Clostridium perfringens type A often isolated; and ascitic birds with cobblestone-appearing livers. Livers with hepatosis had marked proliferation of bile ducts; ascitic livers had normal architecture. Hearts from birds with ascites had elevated right ventricular/total ventricular weight ratios, whereas hearts from normal birds and birds with hepatosis did not. Two isolates of C. perfringens produced necrotic enteritis in experimental birds; an attempt to reproduce hepatosis with these isolates was unsuccessful.