A Unusual Case of Classic Hodgkin Lymphoma (cHL) with Aberrant T-Antigens Expression

Introduction/Objective

T-cell-associated antigens (TCA) are rarely expressed by Hodgkin/Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL) and is associated with uncertain clinical significance.

Methods/Case Report

We present a very recent case of a 68 year-old female with no significant past medical history presented with a large right groin mass for 1 month. She denied any fever, night sweats, fatigue or weight loss. CT abdomen/pelvis showed inguinal/pelvic lymphadenopathy. Resection showed effaced nodal architecture with a vague nodular appearance and with large, atypical nucleolated cells in a background of small, mature lymphocytes and histiocytes. Eosinophils are conspicuously absent in the background. The large cells were polylobated lymphocyte and histiocyte rich (L & H) like, classic HRS cells as well as multinucleated in appearance. The morphologic features overlapped between Classic Hodgkin Lymphoma, and Nodular Lymphocyte Predominant Hodgkin Lymphoma. Given the immunohistochemical (IHC) features of the neoplastic cells [CD45 negative, PAX5+ (weak), CD30+ (strong), CD15+ (majority) and MUM1 +] the diagnosis was most compatible with CHL. Interestingly, a subset of the Hodgkin cells (10-20%) aberrantly expressed a number of T-cell markers (CD2, CD3, CD4, and CD8). However, the background smaller T-cells did not show cytologic atypia or aberrancies of T-cell antigen markers. The large cells were negative for CD43 and ALK1. TCR gamma gene rearrangement was also negative for clonal T-lymphocytes, thus excluding the possibility of peripheral T-cell lymphoma with Hodgkin-like cells. Based on the morphology and IHC profile, this case proves to be CHL with multiple TCA expression including CD2, CD3, CD4 and CD8. She was planned for chemotherapy. Four months after the initial diagnosis and after completion of 2 cycles of chemotherapy, her PET CT scan showed improvement with right inguinal adenopathy being smaller in size and decreased avidity, indicating a response to treatment. She is due for 2 more cycles. Till todate she is doing well with no further symptoms.

Results (if a Case Study enter NA)

NA.

Conclusion

So far reported cases of classic Hodgkin lymphoma (CHL) with aberrant T-cell antigen (TCA) expression were associated with decreased event-free survival and overall survival when compared with TCA-negative CHLs. Our finding contributes to the literature and improves our knowledge of the disease.

1438 The Past, Present and Future Management of Complex Chyle Fistulae

Background

Chyle leak/fistula is a rare complication of oesophageal surgery, usually consequent on an unintended breach of the thoracic duct, its tributaries, or the cisterna chyli. For high volume persistent leaks further surgery has been the traditional approach, however two cases have resulted in a new management approach at this Centre.

Case Series

The first patient, a 49-year-old, developed high volume drain output post three stage oesophagectomy. His jejunostomy feeding was discontinued, total parenteral nutrition and a somatostatin analogue, were commenced. Despite these measures, the drain output remained >1.5litres per day and an exploratory thoracotomy was performed. The second patient, an 81-year-old underwent a transhiatal-oesophagectomy. On postoperative day 10 he developed acute onset shortness of breath, CXR demonstrated a large left sided pleural effusion. CT thorax demonstrated multiloculated complex pleural effusions. US guided pig tail drain was placed in the largest targetable effusion. The fluid was chylous in appearance. In both cases, an interventional radiological approach, not previously performed at this centre, provided definitive management. Lymphangiography was performed via injection of 1mL of Lipoidol® every 5 minutes into the inguinal lymph nodes to identify the cisterna chyli. A guidewire was advanced via the cisterna chyli with coils and glue used to embolize the leaking tracts.

Discussion

The lessons from this experience provide an algorithm for the management of chyle leaks, that will change practice at this centre. Embolization or disruption of thoracic duct and cisterna chyli leaks will be first line therapy for complex chyle leaks, with surgery reserved for where this fails.

POS1162 PREDICTORS OF HOSPITALISATION IN PATIENTS WITH RHEUMATIC DISEASE AND COVID-19 IN IRELAND: DATA FROM THE COVID-19 GLOBAL RHEUMATOLOGY ALLIANCE PHYSICIAN-REPORTED REGISTRY

Background:

There is limited data regarding the risk of hospitalisation in patients with rheumatic disease and COVID-19 in Ireland.

Objectives:

We used the COVID-19 Global Rheumatology Alliance (GRA) registry data to study outcomes and their predictors.

Methods:

We examined data on patients and their disease-related characteristics entered into the COVID-19 GRA provider registry from Ireland (24th March 2020 to 31st August 2020). Multivariable logistic regression was used to assess the association of demographic and clinical characteristics with hospitalisation.

Results:

Of 105 patients, 47 (45.6%) were hospitalised and 10 (9.5%) died. Multivariable logistic regression analysis showed age (OR=1.06, 95%CI 1.01 to 1.10), number of comorbidities (OR=1.93, 95%CI 1.11 to 3.35), and glucocorticoid use (OR=15.01, 95%CI 1.77 to 127.16) were significantly associated with hospitalisation. A diagnosis of inflammatory arthritis was associated with a lower odds of hospitalisation (OR=0.09, 95%CI 0.02 to 0.32).

All significant variable modelMost parsimonious modelUnadjusted OR (95% CI)Adjusted OR (95%CI)*Adjusted p-value*Adjusted OR (95%CI)&Adjusted p-value&Female0.45 (0.20-1.02)0.33 (0.05-2.23)0.34 (0.09-1.36)0.128Age (years)1.08 (1.05-1.11)1.04 (0.97-1.10)0.2241.06 (1.01-1.10)0.010Inflammatory arthritis0.11 (0.05-0.28)0.14 (0.02-0.95)0.0440.09 (0.02-0.32)<0.001Connective Tissue Disease and Other1.56 (0.62 - 3.92)No comorbidities0.11 (0.04-0.30)0.76 (0.09-6.58)0.802Most common comorbiditiesCOPD / asthma4.77 (1.23-18.54)3.09 (0.16-60.07)0.456CVD3.40 (1.31-8.85)0.11 (0.01-1.88)0.129Hypertension3.71 (1.52-9.08)0.56 (0.04-7.94)0.668Obesity0.58 (0.10-3.30)Number of comorbidities (Median, IQR)3.01 (1.92-4.72)2.99 (0.59-15.02)0.1841.93 (1.11-3.35)0.020Never Smokerref.0.889Ever Smoker3.17 (1.18-8.89)1.19 (0.10-13.68)Medication prior to COVID-19 diagnosisGlucocorticoids9.26 (1.95-43.89)18.14 (1.13-290.81)0.04115.01 (1.77-127.16)0.013csDMARD monotherapy0.42 (0.17-1.00)b/tsDMARD (monotherapy or in combination with csDMARD)0.24 (0.10-0.58)1.36 (0.19-9.72)0.557

Conclusion:

Increasing age, comorbidity burden, and glucocorticoid use were associated with hospitalisation, while a diagnosis of inflammatory arthritis was associated with lower odds of hospitalization.

Disclosure of Interests:

Richard Conway Speakers bureau: Janssen, Roche, Sanofi, Abbvie, Elena Nikiphorou Speakers bureau: AbbVie, Eli-Lilly, Gilead, Celltrion, Pfizer, Sanofi, Christiana Demetriou: None declared, Candice Low: None declared, Kelly Leamy: None declared, John Ryan: None declared, Ronan Kavanagh: None declared, Alexander Fraser: None declared, John Carey: None declared, Paul O’Connell: None declared, Rachael Flood: None declared, Ronan Mullan: None declared, David Kane: None declared, Philip Robinson Speakers bureau: UCB, Roche, Pfizer, Gilead, Janssen, Novartis, Eli Lilly, Abbvie, Grant/research support from: Abbvie, UCB, Novartis, Janssen, Pfizer, Jean Liew Grant/research support from: Pfizer, Rebecca Grainger Speakers bureau: Pfizer, Cornerstones, Janssen, Novartis, Abbvie, Geraldine McCarthy: None declared.

Combined rTMS and virtual reality brain-computer interface training for motor recovery after stroke

OBJECTIVE

Combining repetitive transcranial magnetic stimulation (rTMS) with brain-computer interface (BCI) training can address motor impairment after stroke by down-regulating exaggerated inhibition from the contralesional hemisphere and encouraging ipsilesional activation. The objective was to evaluate the efficacy of combined rTMS  +  BCI, compared to sham rTMS  +  BCI, on motor recovery after stroke in subjects with lasting motor paresis.

APPROACH

Three stroke subjects approximately one year post-stroke participated in three weeks of combined rTMS (real or sham) and BCI, followed by three weeks of BCI alone. Behavioral and electrophysiological differences were evaluated at baseline, after three weeks, and after six weeks of treatment.

MAIN RESULTS

Motor improvements were observed in both real rTMS  +  BCI and sham groups, but only the former showed significant alterations in inter-hemispheric inhibition in the desired direction and increased relative ipsilesional cortical activation from fMRI. In addition, significant improvements in BCI performance over time and adequate control of the virtual reality BCI paradigm were observed only in the former group.

SIGNIFICANCE

When combined, the results highlight the feasibility and efficacy of combined rTMS  +  BCI for motor recovery, demonstrated by increased ipsilesional motor activity and improvements in behavioral function for the real rTMS  +  BCI condition in particular. Our findings also demonstrate the utility of BCI training alone, as shown by behavioral improvements for the sham rTMS  +  BCI condition. This study is the first to evaluate combined rTMS and BCI training for motor rehabilitation and provides a foundation for continued work to evaluate the potential of both rTMS and virtual reality BCI training for motor recovery after stroke.

Traumatic pulmonary pseudocyst: An underreported entity

BACKGROUND

Traumatic pulmonary pseudocysts (TPP) are underreported cavitary lesions of the pulmonary parenchyma that can develop following blunt chest trauma. Although the occurrence of traumatic pulmonary pseudocyst is rare, this condition should be considered in the differential diagnosis of any cavitary lesion. Awareness of this injury and its clinical significance is important for successful management in order to avoid medical errors in the course of treatment.

METHODS

A literature search was conducted through Medline using the key phrases "traumatic pulmonary pseudocyst" and "traumatic pneumatocele." Relevant articles, especially those with focus on diagnosis and management of traumatic pneumatocele in adults, were selected. Due to the scarcity of literature and lack of Level I evidence on this subject, studies published in any year were considered.

RESULTS

A search of "traumatic pulmonary pseudocyst" and "traumatic pneumatocele" yielded 114 studies. Most of these were excluded based on inclusion and exclusion criteria. Thirty-five articles were reviewed. The majority of these were individual case studies; only eight articles were considered large case studies (greater than eight patients).

CONCLUSION

Traumatic pulmonary pseudocysts are lesions that occur secondary to blunt chest trauma. Diagnosis is based on a history of trauma and appearance of a cystic lesion on CT. Accurate diagnosis of traumatic pulmonary pseudocyst is imperative to achieve successful outcomes. Failure to do so may lead to unnecessary procedures and complications.

Post-combustion carbon dioxide capture cost reduction to 2030 and beyond

Post-combustion CO₂ capture (PCC) can be achieved using a variety of technologies. Importantly it is applicable to a wide range of processes and may also be retrofitted in certain cases. This paper covers the use of PCC for low carbon power generation from new natural gas combined cycle (NGCC) plants that are expected to be built in the UK in the 2020s and 2030s and that will run into the 2050s. Costs appear potentially comparable with other low carbon and controllable generation sources such as nuclear or renewables plus storage, especially with the lower gas prices that can be expected in a carbon-constrained world. Non-fuel cost reduction is still, however, desirable and, since CO₂ capture is a new application, significant potential is likely to exist. For the NGCC+PCC examples shown in this paper, moving from ‘first of a kind’ (FOAK) to ‘nth of a kind’ (NOAK) gives significant improvements through both reduced financing costs and capital cost reductions. To achieve this the main emphasis needs to be on ‘commercial readiness’, rather than on system-level ‘technical readiness’, and on improvements through innovation activities, supported by underpinning research, that develop novel sub-processes; this will also maintain NOAK status for cost-effective financing. Feasible reductions in the energy penalty for PCC capture have much less impact, reflecting the inherently high levels of efficiency for modern NGCC+PCC plants.

Multiobjective optimization framework for landmark measurement error correction in three-dimensional cephalometric tomography

The purpose of this study is to minimize errors that occur when using a four vs six landmark superimpositioning method in the cranial base to define the co-ordinate system. Cone beam CT volumetric data from ten patients were used for this study. Co-ordinate system transformations were performed. A co-ordinate system was constructed using two planes defined by four anatomical landmarks located by an orthodontist. A second co-ordinate system was constructed using four anatomical landmarks that are corrected using a numerical optimization algorithm for any landmark location operator error using information from six landmarks. The optimization algorithm minimizes the relative distance and angle between the known fixed points in the two images to find the correction. Measurement errors and co-ordinates in all axes were obtained for each co-ordinate system. Significant improvement is observed after using the landmark correction algorithm to position the final co-ordinate system. The errors found in a previous study are significantly reduced. Errors found were between 1 mm and 2 mm. When analysing real patient data, it was found that the 6-point correction algorithm reduced errors between images and increased intrapoint reliability. A novel method of optimizing the overlay of three-dimensional images using a 6-point correction algorithm was introduced and examined. This method demonstrated greater reliability and reproducibility than the previous 4-point correction algorithm.

Revision ACL reconstruction outcomes: MOON cohort

Many clinicians believe that the results of revision anterior cruciate ligament (ACL) reconstruction compare unfavorably with primary ACL reconstruction. However, few prospective studies have evaluated revision ACL reconstruction using validated patient-based metrics. This study was performed to evaluate and compare the results of revision ACL reconstruction and primary ACL reconstruction. The Multicenter Orthopaedic Outcomes Network consortium is an NIH-funded, hypothesis-driven, multicenter prospective cohort study of patients undergoing ACL reconstruction. All patients preoperatively complete a series of validated patient-oriented questionnaires. At scheduled 2-year follow-up all patients are given the same series of questionnaires to complete. The study evaluated the results of 2-year follow-up of revision ACL reconstruction performed in 2001. Parameters evaluated included Marx activity level, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) scores. For this study 446 subjects met inclusion criteria; 2-year follow-up was obtained on 393 (88%). The study group consisted of 55% males with median age of 22 years. There were 33 revision ACL reconstruction cases, for which follow-up was available for 29 (88%). Median baseline Marx (interquartile range) was 12 (8 to 16) and 12 (6 to 16) for the primary ACL reconstruction and revision ACL reconstruction groups, respectively (p= 0.81). At 2 years, median Marx was 9 (4 to 13) and 5 (0 to 10) for the primary ACL reconstruction and revision ACL reconstruction groups, respectively (p= 0.03). Median 2-year IKDC was 75.9 (revision) versus 83.9 (primary) (p=0.003). Median KOOS subscale Knee Related Quality of Life (KRQOL) at 2 years was 62.5 (revision) versus 75 (primary) (p < 0.001), subscale Sports and Recreation was 75 (revision) and 85 (primary) (p = 0.005), subscale Pain was 83.3 (revision) and 91.7 (primary) (p= 0.002). Marx activity score declined at 2-year follow-up in revision ACL reconstruction compared with primary ACL reconstruction. IKDC and KRQOL were significantly decreased in revision ACL reconstruction compared with primary ACL reconstruction at 2-year followup. Revision ACL reconstruction resulted in a significantly worse outcome as measured by these patient-based measures at 2 years.

Vitamin D supplementation versus combined calcium and vitamin D in older female patients - an observational study

BACKGROUND

In most developed countries overt vitamin D deficiency, characterized by rickets or osteomalacia, is now uncommon. However, subclinical vitamin D insufficiency is extremely common and may contribute to the development of skeletal and non-skeletal problems. Standard practice involves supplementation with a combination of vitamin D and calcium although the benefit of adding calcium to vitamin D supplements has not been fully established and may reduce adherence due to its bulky and chalky consistency.

PURPOSE OF STUDY

To compare the effects of vitamin D alone versus vitamin D/calcium supplements on vitamin D levels, bone profile and parathyroid hormone level.

POPULATION

Older (> 65 years) female patients living in the community and long term care institutions.

INTERVENTIONS

Either 800 iu of vitamin D3 or a composite supplement of 800 iu vitamin D3 and 1000 mg calcium were given to patients in an open-labelled observational study. Serum 25-hydroxy-vitamin D, parathyroid hormone, calcium, phosphate and alkaline phosphatase levels were assessed at baseline and after 3 months of treatment.

RESULTS

Serum 25-hydroxy-vitamin D levels rose from baseline levels of 25 ± 16 to 79 ± 16 in those treated with vitamin D alone and from 35 ± 24 nmol/L to 70 ± 24 nmol/L in those treated with vitamin D and calcium. Serum PTH levels fell by similar amounts in both groups. In both community dwellers and institutionalised patients, those treated with vitamin D alone were at least as likely to achieve normalisation of serum vitamin D levels as those on combined calcium/vitamin D treatment.

CONCLUSION

Vitamin D alone appears as effective as combined calcium/vitamin D treatment in restoring serum vitamin D levels in older community dwelling and institutionalised patients. A prospective randomised trial would help confirm these findings.

Failures, re-operations, and complications after autologous chondrocyte implantation--a systematic review

OBJECTIVE

To determine and compare failure, re-operation, and complication rates of all generations and techniques of autologous chondrocyte implantation (ACI).

METHODS

A systematic review of multiple medical databases was performed according to PRISMA guidelines. Levels I-IV evidence were included. Generations of ACI and complications after ACI were explicitly defined. All subject and defect demographic data were analyzed. Modified Coleman Methodology Scores (MCMSs) were calculated for all studies.

RESULTS

82 studies were identified for inclusion (5276 subjects were analyzed; 6080 defects). Ninety percent of the studies in this review were rated poor according to the MCMS. There were 305 failures overall (5.8% subjects; mean time to failure 22 months). Failure rate was highest with periosteal ACI (PACI). Failure rates after PACI, collagen-membrane cover ACI (CACI), second generation, and all-arthroscopic, second-generation ACI were 7.7%, 1.5%, 3.3%, and 0.83%, respectively. The failure rate of arthrotomy-based ACI was 6.1% vs 0.83% for all-arthroscopic ACI. Overall rate of re-operation was 33%. Re-operation rate after PACI, CACI, and second-generation ACI was 36%, 40%, and 18%, respectively. However, upon exclusion of planned second-look arthroscopy, re-operation rate was highest after PACI. Unplanned re-operation rates after PACI, CACI, second-generation, and all-arthroscopic second-generation ACI were 27%, 5%, 5%, and 1.4%, respectively. Low numbers of patients undergoing third-generation ACI precluded comparative analysis of this group.

CONCLUSIONS

Failure rate after all ACI generations is low (1.5-7.7%). Failure rate is highest with PACI, and lower with CACI and second-generation techniques. One out of three ACI patients underwent a re-operation. Unplanned re-operations are seen most often following PACI. Hypertrophy and delamination is most commonly seen after PACI. Arthrofibrosis is most commonly seen after arthrotomy-based ACI. Use of a collagen-membrane cover, second-generation techniques, and all-arthroscopic, second-generation approaches have reduced the failure, complication, and re-operation rate after ACI.

Pasteurization of chicken litter with steam and quicklime to reduce Salmonella Typhimurium

The nursery industry pasteurizes soil with steam and quicklime to reduce plant pathogens. The mechanism of action for quicklime is the resulting exothermic reaction that occurs when the chemical interacts with water and its ability to increase pH levels. These treatments may also reduce pathogens in a commercial poultry house. In this study, a steam sterilization cart simulated conditions used by the nursery industry to treat litter inoculated with Salmonella enterica serovar Typhimurium. A homogenized sample of litter was exposed to steam for 0, 5, 30, or 120 min. Quicklime was used at concentrations of 0 (control), 2.5, 5.0, or 10.0%. All steam treatments, with or without quicklime, significantly reduced Salmonella Typhimurium colonization by at least 3 orders of magnitude. Significant reductions were also observed in the treatments with quicklime alone. Both the steam and the quicklime treatments often reduced colonization to undetectable levels, even when samples were enriched. Therefore, we demonstrated 2 novel techniques for reducing Salmonella Typhimurium in poultry litter. Soil pasteurization potentially offers an environmentally sound means of reducing the pathogens present in used poultry litter.

Sensitivity analysis for plane orientation in three-dimensional cephalometric analysis based on superimposition of serial cone beam computed tomography images

OBJECTIVES

The purpose of this study was to evaluate the potential errors associated with superimposition of serial cone beam CT (CBCT) images utilizing reference planes based on cranial base landmarks using a sensitivity analysis.

METHODS

CBCT images from 62 patients participating in a maxillary expansion clinical trial were analysed. The left and right auditory external meatus (AEM), dorsum foramen magnum (DFM) and the midpoint between the left and right foramen spinosum (ELSA) were used to define a three-dimensional (3D) anatomical reference co-ordinate system. Intraclass correlation coefficients for all four landmarks were obtained. Transformation of the reference system was carried out using the four landmarks and mathematical comparison of values.

RESULTS

Excellent intrareliability values for each dimension were obtained for each landmark. Evaluation of the method to transform the co-ordinate system was first done by comparing interlandmark distances before and after transformations, giving errors in lengths in the order of 10-14% (software rounding error). A sensitivity evaluation was performed by adding 0.25 mm, 0.5 mm and 1 mm error in one axis of the ELSA. A positioning error of 0.25 mm in the ELSA can produce up to 1.0 mm error in other cranial base landmark co-ordinates. These errors could be magnified to distant landmarks where in some cases menton and infraorbital landmarks were displaced 4-6 mm.

CONCLUSIONS

Minor variations in location of the ELSA, both the AEM and the DFM landmarks produce large and potentially clinically significant uncertainty in co-ordinate system alignment.

Effect of object location on the density measurement and Hounsfield conversion in a NewTom 3G cone beam computed tomography unit

OBJECTIVES

The purpose of this study was to determine the effect of an object's location in a cone beam CT imaging chamber (CBCT-NewTom 3G) on its apparent density and to develop a linear conversion coefficient for Hounsfield units (HU) to material density (g cm(-3)) for the NewTom 3G Scanner.

METHODS

Three cylindrical models of materials with different densities were constructed and scanned at five different locations in a NewTom 3G Volume Scanner. The average HU value for each model at each location was obtained using two different types of software. Next, five cylinders of different known densities were scanned at the exact centre of a NewTom 3G Scanner. The collected data were analysed using the same two types of software to determine a standard linear relationship between density and HU for each type of software.

RESULTS

There is no statistical significance of location of an object within the CBCT scanner on determination of its density. A linear relationship between the density of an object and the HU of a scan was rho = 0.001(HU)+1.19 with an R2 value of 0.893 (where density, rho, is measured in g cm(-3)). This equation is to be used on a range between 1.42 g cm(-3) and 0.4456 g cm(-3).

CONCLUSIONS

A linear relationship can be used to determine the density of materials (in the density range of bone) from the HU values of a CBCT scan. This relationship is not affected by the object's location within the scanner itself.

Probe-guided localization of cancer deposits using [18F]fluorodeoxyglucose

In recent years, several probes have been developed to allow for the intraoperative detection of tumour tissue using [18F]fluorodeoxyglucose (FDG). Detector designs include high-energy gamma and beta probes, as well as combination devices with background rejection capabilities. Some laboratory prototypes and commercialized systems have demonstrated reasonable sensitivities for 511 keV photons and /or b particles emitted from 18F for in vivo use. This review focuses on the ability of these devices to detect tumour deposits in the low-contrast environment of the operating room . Important technical and biological factors that influence tumour-to-background contrast are discussed and potential future applications and developments are highlighted. In addition, we evaluate the limited data on absorbed doses resulting from [18F] FDG administration immediately prior to surgery that indicate acceptable levels of radiation exposure to operating room personnel.

MC1R variants correlate with thinhorn sheep colour cline but not individual colour

The melanocortin 1 receptor (MC1R) gene has provided a window on the evolution of colour polymorphisms. Recent studies have demonstrated associations between MC1R and melanism in a number of wildlife species. Thinhorn sheep ( Ovis dalli Nelson, 1884) are a possible species to test for association between MC1R polymorphisms and melanism. Across their range the pelage colour of thinhorn sheep intergrades between all white phenotypes to very dark phenotypes. Most thinhorn sheep are white; however, there is a 1200 km cline from light to dark sheep that occurs over three genetically distinct polymorphic populations. We sequenced the entire MC1R gene from 40 individuals across the range of thinhorn sheep. We found a single nucleotide polymorphism in MC1R at base pair position 921 that coincided with the geographic cline. However, at the individual level we found no relationship between individual melanism and genotype.

Horn growth rate and longevity: implications for natural and artificial selection in thinhorn sheep (Ovis dalli)

We used horn measurements from natural and hunted mortalities of male thinhorn sheep Ovis dalli from Yukon Territory, Canada, to examine the relationship between rapid growth early in life and longevity. We found that rapid growth was associated with reduced longevity for sheep aged 5 years and older for both the hunted and natural mortality data sets. The negative relationship between growth rate and longevity in hunted sheep can at least partially be explained by morphologically biased hunting regulations. The same trend was evident from natural mortalities from populations that were not hunted or underwent very limited hunting, suggesting a naturally imposed mortality cost directly or indirectly associated with rapid growth. Age and growth rate were both positively associated with horn size at death for both data sets, however of the two growth rate appeared to be a better predictor. Large horn size can be achieved both by individuals that grow horns rapidly and by those that have greater longevity, and the trade-off between growth rate and longevity could limit horn size evolution in this species. The similarity in the relationship between growth rate and longevity for hunted and natural mortalities suggests that horn growth rate should not respond to artificial selection. Our study highlights the need for the existence and study of protected populations to properly assess the impacts of selective harvesting.

Density conversion factor determined using a cone-beam computed tomography unit NewTom QR-DVT 9000

OBJECTIVE

The purpose of this study was to determine a conversion coefficient for Hounsfield Units (HU) to material density (g cm(-3)) obtained from cone-beam computed tomography (CBCT-NewTom QR-DVT 9000) data.

METHODS

Six cylindrical models of materials with different densities were made and scanned using the NewTom QR-DVT 9000 Volume Scanner. The raw data were converted into DICOM format and analysed using Merge eFilm and AMIRA to determine the HU of different areas of the models.

RESULTS

There was no significant difference (P = 0.846) between the HU given by each piece of software. A linear regression was performed using the density, rho (g cm(-3)), as the dependent variable in terms of the HU (H). The regression equation obtained was rho = 0.002H-0.381 with an R2 value of 0.986. The standard error of the estimation is 27.104 HU in the case of the Hounsfield Units and 0.064 g cm(-3) in the case of density.

CONCLUSION

CBCT provides an effective option for determination of material density expressed as Hounsfield Units.

Evidence for cryptic glacial refugia from North American mountain sheep mitochondrial DNA

The separation of populations by ice sheets into large refugia can account for much of the genetic diversity found in present day populations. The evolutionary implications of small glacial refugia have not been as thoroughly explored. To examine refugial origins of North American mountain sheep Ovis spp., we analyzed a 604 bp portion of the mitochondrial DNA (mtDNA) control region from 223 O. dalli and O. canadensis. Major refugia were identified in eastern Beringia and southern North America, and we found evidence for two smaller refugia situated between the Laurentide and Cordilleran glaciers. Our results are the first to demonstrate support for survival of any organism in the latter two refugia. These refugia also appear to have conserved a genetic signal that confirms past hybridization of O. dalli and O. canadensis.

Detecting the signature of selection on immune genes in highly structured populations of wild sheep (Ovis dalli)

The confounding effects of population structure complicate efforts to identify regions of the genome under the influence of selection in natural populations. Here we test for evidence of selection in three genes involved in vertebrate immune function - the major histocompatibility complex (MHC), interferon gamma (IFNG) and natural resistance associated macrophage polymorphism (NRAMP) - in highly structured populations of wild thinhorn sheep (Ovis dalli). We examined patterns of variation at microsatellite loci linked to these gene regions and at the DNA sequence level. Simple Watterson's tests indicated balancing selection at all three gene regions. However, evidence for selection was confounded by population structure, as the Watterson's test statistics from linked markers were not outside of the range of values from unlinked and presumably neutral microsatellites. The translated coding sequences of thinhorn IFNG and NRAMP are fixed and identical to those of domestic sheep (Ovis aries). In contrast, the thinhorn MHC DRB locus shows significant evidence of overdominance through both an excess of nonsynonymous substitution and trans-species polymorphism. The failure to detect balancing selection at microsatellite loci linked to the MHC is likely the result of recombination between the markers and expressed gene regions.

Gender- and age-class-specific reactions to human disturbance in a sexually dimorphic ungulate

According to optimality theory, an individual's characteristics should play a major part in determining antipredator strategies. We studied behavioural reactions to human presence of gender and age classes of 35 thinhorn sheep (Ovis dalli Nelson, 1884) in late winter 2001 in Faro, Yukon Territory, Canada. The behaviour of undisturbed sheep was observed from distances of 400–1200 m and compared with the behaviour recorded when one or two people were in close proximity to the sheep. Ewes decreased bedding and increased foraging when humans were present, but there were no changes in these behaviours in rams. Disturbance caused an increase in vigilance and a trend was found for adults to react more strongly to disturbance than juveniles. We demonstrate the importance for disturbance research of gaining detailed information about all different kinds of population members and using applicable statistical tests in the data analyses.

Mullerian inhibiting substance suppresses tumor growth in the C3(1)T antigen transgenic mouse mammary carcinoma model

Mullerian inhibiting substance (MIS) inhibits breast cancer cell growth in vitro. To extend the use of MIS to treat breast cancer, it is essential to test the responsiveness of mammary tumor growth to MIS in vivo. Mammary tumors arising in the C3(1) T antigen mouse model expressed the MIS type II receptor, and MIS in vitro inhibited the growth of cells derived from tumors. Administration of MIS to mice was associated with a lower number of palpable mammary tumors compared with vehicle-treated mice (P=0.048), and the mean mammary tumor weight in the MIS-treated group was significantly lower compared with the control group (P=0.029). Analysis of proliferating cell nuclear antigen (PCNA) expression and caspase-3 cleavage in tumors revealed that exposure to MIS was associated with decreased proliferation and increased apoptosis, respectively, and was not caused by a decline in T antigen expression. The effect of MIS on tumor growth was also evaluated on xenografted human breast cancer cell line MDA-MB-468, which is estrogen receptor- and retinoblastoma-negative and expresses mutant p53, and thus complements the C3(1)Tag mouse mammary tumors that do not express estrogen receptor and have functional inactivation of retinoblastoma and p53. In agreement with results observed in the transgenic mice, MIS decreased the rate of MDA-MB-468 tumor growth and the gain in mean tumor volume in severe combined immunodeficient mice compared with vehicle-treated controls (P=0.004). These results suggest that MIS can suppress the growth of mammary tumors in vivo.

Abnormal motor behavior and vestibular dysfunction in the stargazer mouse mutant

In stargazer mutant mice, a mutation in the gene encoding stargazin results in absence epilepsy, cerebellar ataxia, and a characteristic abnormal motor syndrome. The main goal of the current studies was to characterize the nature and source of the abnormal motor behavior. Because the stargazer motor syndrome resembles that of other rodents with vestibular dysfunction, the motor abnormalities were compared with those of normal mice treated with toxins known to damage the vestibular system. Quantitative open field assessments revealed that the stargazer mice display a motor syndrome very similar to that exhibited by mice with toxin-induced vestibulopathy. However, stargazer mice also displayed several additional behaviors, such as ataxic gait and sustained extensor movements of the neck. In addition, stargazer mice performed worse than mice with toxin-induced vestibulopathy in most standard tests of motor function. Motor function was also impaired on each of four behavioral tests sensitive to vestibular function. Because of the close associations between the vestibular and auditory systems, tests of auditory function were also employed. The stargazer mutants exhibited relatively normal auditory brainstem evoked responses but no apparent acoustic startle reflex. Histological examination of vestibular sensory epithelium at the light and electron microscopic levels confirmed the existence of abnormalities in the stargazer mutants. These results imply a previously unrecognized role for stargazin in the normal functions of the vestibular system and indicate that some, but not all, of the abnormal motor syndrome of stargazer mice can be attributed to vestibular dysfunction.

Population genetic structure of North American thinhorn sheep (Ovis dalli)

The thinhorn sheep (Ovis dalli ssp.) provides a rare example of a North American large mammal that occupies most of its native range and maintains close to ancestral population size. There are currently two recognized subspecies, Dall's sheep (O. d. dalli) and Stone's sheep (O. d. stonei), the validity of which remains uncertain. We investigated the spatial genetic structure of thinhorn sheep populations representing both subspecies by genotyping individuals (n = 919) from across the species range at 12 variable microsatellite loci. We found high levels of genetic diversity within (HE = 0.722) and significant genetic structure among the 24 sampled areas (FST = 0.160). Genetic distance measures and Bayesian clustering analyses revealed the presence of at least eight subpopulations that are delineated by mountain range topology. A strong overall pattern of isolation-by-distance is evident across the sampling range (r = 0.75, P < 0.001) suggesting limited dispersal and extensive philopatry. Partial Mantel tests of this relationship showed mountain range distinctions represent significant barriers to gene flow (P = 0.0001), supporting the Bayesian analyses. Genetic structure was more strongly pronounced in southern Yukon and Alaska than elsewhere. We also show evidence for genetic differences between the two currently recognized thinhorn subspecies.

5-HT(2B) receptors play a key role in mediating the excitatory effects of 5-HT in human colon in vitro

1. 5-Hydroxytryptamine (5-HT) is known to produce a number of different effects in the gastrointestinal tract of various species, and has been proposed to play a key role in a number of intestinal disorders in man, including irritable bowel syndrome (IBS), although the receptors involved have yet to be established. The aim of the present study was to investigate the distribution and function of 5-HT(2B) receptors in human colon, and to establish their possible role in the aetiology of IBS. 2. The distribution of 5-HT(2B) receptor mRNA and protein were investigated by quantitative RT - PCR, Western analysis and immunocytochemistry. High levels of both mRNA and protein for 5-HT(2B) receptors were found throughout the human gastrointestinal tract, and in particular in colon, where 5-HT(2B) receptors were found predominantly in the longitudinal and circular smooth muscle layers within the muscularis externa, and in the myenteric nerve plexus lying between these two layers. 3. Electrical field stimulation of longitudinal muscle preparations of human colon mounted in organ baths resulted in neuronally-mediated contractile responses, that were significantly potentiated by application of 5-HT (up to 10(-7) M), with a pEC(50) of 8.2 +/- 0.1 (n=49 donors). The response to 5-HT was inhibited by a number of selective 5-HT(2B) receptor antagonists. 4. This study has shown for the first time that, in contrast to animal studies, the excitatory effects of 5-HT in human colon are mediated by 5-HT(2B) receptors. It is proposed that these receptors contribute to the putative 5-HT-induced colonic smooth muscle hypersensitivity associated with IBS.

Quantitative analysis of DNA binding by the Escherichia coli arginine repressor

Allosteric activation of the hexameric arginine repressor (ArgR) for specific operator DNA binding appears to involve alteration in its quaternary structure. Current models for activation include subunit assembly and/or domain rearrangements in response to binding of the coeffector l-arginine. To investigate the molecular basis for ArgR operator interactions, we have carried out a series of quantitative analyses of ArgR subunit assembly and of the affinity, stoichiometry, cooperativity, and l-arginine- and DNA sequence-dependence of ArgR-DNA binding. The results indicate that subunit assembly plays no role in activation, although communication among subunits of the ArgR hexamer is required for specific DNA binding. The data suggest that DNA is also an allosteric effector of ArgR.