Brucellosis emergence in the Canadian Arctic

Brucellosis is an important zoonotic disease affecting animals and subsistence harvesters in the circumarctic. We investigated recent trends (2015-2022) of brucellosis seropositivity in caribou (Rangifer tarandus) and muskoxen (Ovibos moschatus) in the Central Canadian Arctic by using data from community-based wildlife health surveillance programs. The overall sample prevalence of Brucella antibodies was 10.0% (n = 271) in muskoxen and 15.5% (n = 277) in caribou. Sample seroprevalence in muskoxen varied geographically with an increasing trend of exposure on NW Victoria Island (from 0% to 36.8% between 2016 and 2022; Kendall tau = 0.283, p = 0.001). The presence of Brucella suis biovar 4 was confirmed by culture from clinical cases in this area. Our results indicate that Brucella suis biovar 4 continues to circulate in the Central Canadian Arctic in caribou and muskoxen and may be now circulating in muskoxen independently from caribou. These findings highlight the need to better understand the ecology and drivers of brucellosis emergence in Arctic multi-host systems.

Detection and Phylogenetic Analysis of Orf Virus and Muskox Rhadinovirus 1 from Muskoxen (Ovibos moschatus) in the Canadian Arctic

Orf virus (genus Parapoxvirus) has been associated with gross skin lesions on muskoxen (Ovibos moschatus) from Victoria Island, Nunavut, Canada, where muskox populations are experiencing population declines. Orf virus causes painful proliferative and necrotizing dermatitis upon viral replication and shedding, which may lead to animal morbidity or mortality through secondary infections and starvation. Herpesvirus, known to cause gross lesions on skin and mucosa during active viral replication, has also been documented in muskoxen but to date has not been associated with clinical disease. Our objective was to characterize the variation of orf virus and herpesvirus in wild muskoxen of the Canadian Arctic. Tissue samples including gross skin lesions from the nose, lips, and/or legs were opportunistically collected from muskoxen on Victoria Island, Nunavut and Northwest Territories, and mainland Nunavut, Canada, from 2015 to 2017. Sampled muskoxen varied in age, sex, location, hunt type, and body condition. Tissues from 60 muskoxen were tested for genetic evidence of orf virus and herpesvirus infection using PCR targeting key viral genes. Tissues from 38 muskoxen, including 15 with gross lesions, were also examined for histological evidence of orf virus and herpesvirus infection. Eleven muskoxen (10 from Victoria Island and one from mainland Nunavut) with gross lesions had microscopic lesions consistent with orf virus infection. Muskox rhadinovirus 1, a gammaherpesvirus endemic to muskoxen, was detected in 33 (55%) muskoxen including 17 with gross lesions. In all tissues examined, there was no histological evidence of herpesvirus-specific disease. Sequencing and characterization of amplified PCR products using phylogenetic analysis indicated that a strain of orf virus, which appears to be unique, is likely to be endemic in muskoxen from Victoria Island and mainland Nunavut. Many of the muskoxen are also subclinically infected with a known muskox-endemic strain of herpesvirus.

An integrative and multi-indicator approach for wildlife health applied to an endangered caribou herd

Assessing wildlife health in remote regions requires a multi-faceted approach, which commonly involves convenient samplings and the need of identifying and targeting relevant and informative indicators. We applied a novel wildlife health framework and critically assessed the value of different indicators for understanding the health status and trends of an endangered tundra caribou population. Samples and data from the Dolphin and Union caribou herd were obtained between 2015 and 2021, from community-based surveillance programs and from captured animals. We documented and categorized indicators into health determinants (infectious diseases and trace elements), processes (cortisol, pathology), and health outcomes (pregnancy and body condition). During a recent period of steep population decline, our results indicated a relatively good body condition and pregnancy rates, and decreasing levels of stress, along with a low adult cow survival. We detected multiple factors as potential contributors to the reduced survival, including Brucella suis biovar 4, Erysipelothrix rhusiopathiae and lower hair trace minerals. These results remark the need of targeted studies to improve detection and investigations on caribou mortalities. We also identified differences in health indicators between captured and hunter sampled caribou, highlighting the importance of accounting for sampling biases. This integrative approach that drew on multiple data sources has provided unprecedented knowledge on the health in this herd and highlights the value of documenting individual animal health to understand causes of wildlife declines.

Tularemia above the Treeline: Climate and Rodent Abundance Influences Exposure of a Sentinel Species, the Arctic Fox (Vulpes lagopus), to Francisella tularensis

Tularemia is a zoonotic disease found throughout most of the northern hemisphere that may experience range expansion with warming temperatures. Rodents and lagomorphs are reservoirs for the disease, and outbreaks of tularemia often follow peaks in their abundance. As small mammals dominate the diet of arctic foxes (Vulpes lagopus), we determined whether they may serve as sentinels by identifying antibodies in live-captured and harvested foxes from northern Canada. Overall seroprevalence was 2% (CI95 1-2%) in 176 foxes harvested in 2018-2019 compared to 17% (CI95 12-22%) of 230 foxes captured live in 2011-2021. Prevalence was at an all-time high in 2018, following a peak in vole abundance in 2017. Antibodies were identified in fox pups born in 2018 and 2019, suggesting that F. tularensis was actively transmitted during the summers. High precipitation during the summer, increased snow cover and colder temperatures in May, and a higher abundance of voles were all associated with increased seroprevalence in live-captured foxes. Thus, exposure to F. tularensis is largely mediated through climate and rodent populations in the Canadian Arctic, and arctic foxes are useful sentinels for F. tularensis in northern ecosystems. Further studies should investigate whether infection impacts arctic fox survival and reproductive success in the circumpolar North.

Prognostic power of a new index of right ventricle-pulmonary artery coupling based on right ventricular volumes in patients with secondary tricuspid regurgitation

Background

Although echocardiographic surrogates of right ventricular -arterial coupling (RVAC) have been reported to be associated with outcome in patients with moderate or severe secondary tricuspid regurgitation (STR), pulmonary artery systolic pressure (SPAP) is difficult to be estimated using echocardiography in patients with severe STR.

Purpose

Accordingly, we evaluated the predictive power of indexes of RVAC obtained using RV volumes measured using three-dimensional echocardiography (3DE).

Methods

We prospectively enrolled 180 patients with moderate or severe STR and complete two-dimensional, Doppler and 3DE data. The composite endpoint of death for any cause and heart failure hospitalization was used as primary outcome.

Results

After a median follow up of 24 months (IQR: 2–48), 72 patients (40%) reached the primary endpoint. Most of the echocardiographic parameters of RV function were associated with outcomes. Among the different parameters of RVAC, the receiver operating curve (ROC) analysis selected the ratio between (RV stroke volume [SV]-RegVol)/ RV End-systolic volume (ESV) (i.e. the RV forward SV/ESV) as the best predictor of the combined endpoint (AUC 0.80 [IC 95% 0.73–087]), with a threshold value of 0.49.

Event-free survival of patients with RV forward SV/ESV higher and lower 0.49 has been performed (Figure 1).

Multivariable Cox proportional hazards models were constructed (Figure 2). Adding sequentially the 3D-RVEF, TAPSE/SPAP and the forward RV SV/RV ESV on top of a basal model made of TR severity, New York Heart Association (NYHA) functional class and tricuspid anulus plane systolic excursion (TAPSE), the χ2 of the model increased from 40 to 43 (p=0.13) by adding 3D RVEF, from 43 to 46 (p=0.04) by adding TAPSE/SPAP, and from 46 to 51 (p=0.02) by adding RV forward SV/ESV. Severe TR (HR 3.53 [CI 95%: 1.84–6.78], p<0.001) and RV forward SV/ESV <0.49 (HR 2.45 [CI 95% 1.16–5.18], p=0.02) were the only parameters independently associated with outcome.

Conclusions

The RV forward SV/ESV is an index of RVAC obtained by 3DE which is independent from SPAP and it is strongly associated with the occurrence of death or heart failure hospitalization in patients with STR.

Funding Acknowledgement

Type of funding sources: None.

Routine use of automated strain analysis and 3D echocardiography provides a more comprehensive assessment of cardiac chambers than conventional 2D echocardiography and is time-saving

Funding Acknowledgements

Type of funding sources: None.

Background. In most laboratories three-dimensional echocardiography (3DE) and longitudinal strain (Lstrain) analysis are not part of the routine studies. Although these modalities have been shown to provide additional clinical information and prognostic value compared to conventional two-dimensional echocardiography (2DE), their acquisition and analysis are perceived as being time-consuming.  Recently, new automated tools have been developed to perform accurate, fast and reproducible analyses of heart chambers’ geometry and function. However, their cost-effectiveness when compared to conventional 2DE remains to be demonstrated.

Aim. We designed a prospective, multicenter, observational study aimed to compare the time required for the acquisition and analysis of conventional transthoracic 2DE vs advanced echocardiography (AEcho, i.e. 3DE+ Lstrain) for the assessment of cardiac chambers and myocardial mechanics.

Methods. According to current guidelines, 196 consecutive patients referred for clinically indicated echocardiography underwent complete 2DE and Doppler echocardiography. In addition, 3DE datasets of the left atrium (LA), left and right ventricle (LV, RV) were acquired using automated 3DE software package (Heart Model). Acquisition time for both 2DE and 3DE images were recorded. Conventional 2DE analyses of LA (biplane volume), LV (biplane volumes and mass) and RV (both linear dimensions, areas, and longitudinal function) were performed following current guidelines, and the time required for acquisition and analysis was recorded. The time spent for AEcho analysis (both 3DE volumetric analysis and Lstrain of LA, LV and RV) was also recorded.

Results. Feasibility of AEcho was 86% (169 patients). The additional time for 3D dataset acquisition over conventional 2DE was 38 ± 0.16 sec. Quantitative analysis of the cardiac chambers by 2DE required an average of 5.55 ± 1.51 min vs 4.25 ± 1.23 min using AEcho (p < 0.001). Total time for both 3D dataset acquisition and AEcho assessment was 5.03 ± 1.28 min vs 5.55 ± 1.51 min of 2DE analysis alone (p < 0.001). Globally, AEcho provided a more comprehensive assessment of heart chambers than 2DE (Table). Moreover, the time spent for 3DE dataset acquisition and AEcho analysis on top of standard 2DE acquisition was significantly shorter compared to the 2DE acquisition and analysis (18:50 ± 4.23 vs 19:42 ± 4.24 min, p < 0.001) (Table).

Conclusions. Our data showed that the use of new AEcho automated tools are highly feasible resulting in significant time-savings compared to standard 2DE evaluation, while providing significant additional information. Abstract Table

Impact of leaflet-tethering angle correction on the assessment of tricuspid regurgitation severity using the PISA method

Funding Acknowledgements

Type of funding sources: None.

Background

Severe tricuspid regurgitation (TR) is associated with excess mortality and morbidity. Therefore, assessment of TR severity is pivotal. Calculation of the effective regurgitant orifice area (EROA) and the regurgitant volume (RVol) using flow convergence method (PISA) by echocardiography are still the recommended parameters to define TR severity. However, the distortion of the proximal convergence zone related to the extent of valve leaflet tethering may result in smaller PISA radius and in underestimation of TR severity. Correcting for the angle of the leaflet tethering could reduce errors due to geometric assumption of a flat valvular plane and improve the accuracy of the calculations.

Purpose: The aims of our study were

(1) to evaluate whether taking into account the extent of leaflet tethering by applying the angle correction (AC) in the PISA formula improves the accuracy of the quantitative assessment of TR severity; (2) to assess the potential clinical impact of AC.

Methods

Forty-one patients with functional TR (73.5 ± 11.8 years,51% men,36% sinus rhythm,17% severe), underwent 2D  and 3D echocardiography. We compared the RVol obtained by volumetric method (as reference) with the RVol by PISA with and without AC. TR RVol by volumetric method was calculated as: total RV stroke volume (RVSV) – left ventricular forward SV (LVSV), where RVSV was obtained by subtracting the end-systolic from end-diastolic RV volume measured by 3D echocardiography and LV SV was calculated by multiplying LV outflow area by velocity time integral (VTI)  (Fig. 1). TR RVol by PISA was calculated as EROA x VTITR. Uncorrected EROA was calculated using the formula: 6.28 r2 xVa/ PeakVTR (r - PISA radius, Va, aliasing velocity, PeakVTR – TR peak velocity). The corrected EROA accounting for the PISA geometric distortion by leaflet tethering angle (α) was calculated as: 6.28 r2 x Va (α/180)/ PeakV TR (PISAac), where α was measured using a protractor generated by dedicated software.

Results

Application of AC to PISA method resulted in larger EROA and RVol (0.34± 0.38 cm2 vs 0.24± 0.24cm2 and, 25.2± 19.3 mL vs 18.6 ± 13.1mL, respectively). The percentage change in EROAac was over 40%. When compared to the volumetric method, RVol by corrected PISA method was significantly closer and correlated (bias -3.95mL, LOA ± 6.41 mL,  r= .987; p< .001) than the conventional PISA without AC (bias -10.5 mL, LOA ± 15 mL, r= .975). Angle correction resulted in a change of TR severity in 32% of cases (Fig. 2) and in a greater concordance of TR severity grade with the volumetric method (75%, 31/41 with AC vs 52%, 22/41 without AC).

Conclusions

Angle-corrected PISA method that accounts for the extent of the leaflet tethering in TR provided significantly larger TR RVol that were closely correlated with the volumetric RVol by 3D echocardiography. A simple geometric angle correction of the proximal flow with PISA method reclassified up to 1/3 of patients with functional TR. Abstract Figure. Representation of study method  Abstract Figure. Reclassification of TR severity

Automated left atrial volume measurement by two-dimensional speckle-tracking echocardiography: feasibility, accuracy and reproducibility

Funding Acknowledgements

Type of funding sources: None.

Introduction - A by-product of left atrial (LA) strain analysis is the automated measurement of LA maximal volume (LAVmax), which may decrease the time of echocardiography reporting, and increase the reproducibility of the LAVmax measurement. However, the automated measurement of LAVmax by two-dimensional speckle-tracking analysis (2DSTE) has never been validated.

Purpose – Accordingly, we sought to: i. assess the feasibility of automated LAVmax measurement by 2DSTE; ii.  compare the automated LAVmax by 2DSTE with conventional two-dimensional (2DE) biplane and three-dimensional echocardiography (3DE) measurements; and iii. evaluate the accuracy and reproducibility of the three echocardiography techniques.

Methods – LAVmax (34­-197 mL) were prospectively obtained from 198/210 (feasibility 94%) consecutive patients with various cardiac diseases (median age 67 years, 126 men) by 2DSTE, 2DE and 3DE.

Results – 2DE and 2DSTE measurements resulted in similar LAVmax values (bias = 1.5 mL, limits of agreement, LOA ± 7.5 mL), and slightly underestimated 3DE LAVmax (biases=-5 mL, LOA ± 17 mL, and -6 mL, LOA ± 16 mL, respectively). LAVmax by 2DSTE and 2DE were strongly correlated to those obtained by cardiac magnetic resonance (CMR) (r=.946, and r=.935, respectively; p<.001). However, LAVmax obtained by 2DSTE (bias=-9.5 mL, LOA ± 16 mL), and 2DE (bias=-8 mL, LOA ± 17 mL) were significantly smaller than those measured by CMR. Conversely, 3DE LAVmax were similar to CMR (bias=-2 ml, LOA ± 10 mL). Excellent intra- and inter-observer intraclass correlation coefficients were found for 3DE (0.995 and 0.995), 2DE (0.990 and 0.988), and 2DSTE (0.990 and 0.989).

Conclusion – Automated LAVmax measurement by 2DSTE is highly feasible, highly reproducible, and provided similar values to conventional 2DE calculations in consecutive patients with a wide range of LAVmax. Abstract Figure. Echocardiography and CMR correlations  Abstract Figure. Echocardiography techniques correlations

Prognostic value of different echocardiographic indices reflecting right ventriculo-arterial coupling in a large cohort of patients with various cardiac diseases

Funding Acknowledgements

Type of funding sources: None.

Introduction – Non-invasive parameters used to assess right ventricular (RV) function, i.e. tricuspid annular plane systolic excursion (TAPSE), RV fractional area change (FAC), RV ejection fraction (RVEF), and RV free-wall longitudinal strain (RVFWLS) have shown their prognostic implications. However, since they are extremely load dependent, they do not provide an accurate representation of the RV intrinsic performance. On the other end, invasive indices of RV-arterial coupling (RVAC) derived from pressure-volume loops are not routinely performed, rising the urgency for more feasible, and reliable non-invasive estimates of RVAC.

Purpose – To: i. evaluate the prognostic value of echocardiography-derived RVAC surrogates: RVEF/systolic pulmonary artery pressure (sPAP), RVFWLS/sPAP, TAPSE/sPAP, FAC/sPAP, and RV stroke volume/end-systolic volume (SV/ESV), ii. identify the cut-off values associated to all-cause mortality; and iii. compare their prognostic value with that of classical parameters of RV function.

Methods – We prospectively enrolled 366 patients with various cardiac diseases, undergoing clinically-indicated comprehensive two- and three-dimensional echocardiography.

Results – During a mean follow-up of 7.6 ± 1 years, 80 (21.9%) patients died. At univariable Cox regression, most of the echocardiographic parameters were related to all-cause mortality. The echocardiographic parameters with significance at univariable analysis (p < 0.01) were included in a multivariable regression model. Left ventricular ejection fraction (LVEF), RVEF, TAPSE, RVEF/sPAP and RVFWLS/sPAP remained independently associated to all-cause mortality (p < 0.05 for all). Subsequently, they were tested in receiving operator characteristics (ROC) curves. At ROC analysis, RVEF/sPAP (area under the curve, AUC = 0.807, p < 0.001) and RVFWLS/sPAP (AUC = 0.743, p < 0.001) showed the greatest predictive value (p < 0.001 between them). However, all RV parameters significantly improved their prognostic values after indexing for sPAP (p < 0.01 for all). The best cut-offs to predict the outcome were 1.5 for RVEF/sPAP (specificity 71%, sensitivity 83%) and 0.67 for RVFWLS/sPAP (specificity 72%, sensitivity 68%). At Kaplan-Meier analysis, patients with reduced RVAC (less than the predefined cut-offs) had significantly lower probability of survival (p < 0.001 for all).

Conclusion – RVAC surrogates provide incremental prognostic value compared to standard RV functional measurements. RVEF/sPAP, with a cut-off value of 1.5, was the best parameter for risk stratification, and was independently related to all-cause mortality. Abstract Figure. Prognostic value of RVAC surrogates  Abstract Figure. Kaplan-Meier curves survival probability

Right heart chambers geometry and function in patients with the atrial and the ventricular phenotypes of functional tricuspid regurgitation

Funding Acknowledgements

Type of funding sources: None.

Introduction — Atrial functional tricuspid regurgitation (A-FTR) is a recently defined phenotype of FTR associated with persistent/permanent atrial fibrillation. Differently from the classical ventricular form of FTR (V-FTR), patients with A-FTR might present with severely dilated right atrium (RA) and tricuspid annulus (TA), and with preserved right ventricular (RV) size and systolic function. However, the geometry and function of the RV, RA and TA in patients with A-FTR and V-FTR remain to be systematically evaluated.

Purpose — Accordingly, we sought to: i. study the geometry and function of the RV, RA and TA in A-FTR by two- and three-dimensional transthoracic echocardiography; and ii. compare them with those found in V-FTR.

Methods — We prospectively analysed 113 (44 men, age 68 ± 18 years) FTR patients (A-FTR = 55 and V-FTR = 58) that were compared to two groups of age- and sex-matched controls to develop the respective Z-scores.

Results — The severity of FTR, and the degree of TA dilation were similar in A-FTR and V-FTR patients. The Z-scores of RV size were significantly larger, and those of RV function were significantly lower in V-FTR than in A-FTR (p < 0.001 for all). The RA was significantly enlarged in both A-FTR and V-FTR compared to controls (p < 0.001, Z-scores > 2), with similar RA maximal volumes (RAVmax) between A-FTR and V-FTR (p = 0.2). Whereas, the RA minimal volumes (RAVmin) were significantly larger in A-FTR than in V-FTR (p = 0.001).

Conclusion — Despite similar degrees of FTR, RAVmax and TA size, A-FTR patients show larger RAVmin than V-FTR patients. Conversely, V-FTR patients show dilated, more elliptic and dysfunctional RV than A-FTR patients. Abstract Figure. A-FTR versus V-FTR  Abstract Figure. Remodelling patterns in A-FTR and V-FTR

Telemedicine during the SARS-Cov-2 pandemic lockdown: Monitoring stress and quality of sleep in patients with epilepsy

SARS-CoV-2 pandemic heavily hit the western healthcare system saturating the hospital beds in wards and clogging the emergency departments. To avoid the collapse of Italian hospitals, office visits to outpatients were limited to emergencies and the general population went in a lockdown state. Physicians had to approach new problems in the management of chronic patients who could not leave their homes. In our experience as epilepsy clinic, the use of telemedicine was of crucial importance for monitoring our patients: phone call during lockdown let us monitor the stability of our 38 patients and psychometric parameters and habits that could influence seizures frequency. In particular, we found that in our patients, sleep quality was low resulting in high daily sleepiness and associated high stress levels. Secondly, we found an increase in daily screen hours and an association with daily sleepiness. In conclusion, we report our experience in managing people with epilepsy during the lockdown, underlining the utility of telemedicine as a valid monitoring tool and the necessity of a psychometric and behavioral screening.

Trichinella nativa and Trichinella T6 in arctic foxes (Vulpes lagopus) from northern Canada

Parasitic zoonotic nematodes of the genus Trichinella circulate in wildlife and domestic hosts worldwide through the ingestion of infected meat. Due to their role as scavengers and predators in terrestrial and marine arctic ecosystems, Arctic foxes (Vulpes lagopus) are ideal sentinels for the detection of Trichinella spp. In this study, we determined the prevalence, larval intensity, and species of Trichinella from 91 trapped Arctic foxes collected around the northern Canadian communities of Sachs Harbour (Ikaahuk) on Banks Island (n = 23), and Ulukhaktok and Cambridge Bay (Ikaluktutiak) on Victoria Island (n = 68). Using pepsin-HCl digestion, larvae of Trichinella spp. were recovered from the left forelimb muscle (flexor carpi ulnaris) in 19 of the 91 foxes (21% prevalence, 95% CI: 14–30%). For the first time in Arctic foxes in Canada, Trichinella species were identified using multiplex PCR that was followed up with PCR-RFLP to distinguish between T. nativa and T. chanchalensis. All infected foxes harbored T. nativa, and one fox was co-infected with Trichinella T6; the latter is a new host record. Age of the fox was significantly associated with Trichinella spp. infection and the odds of being infected were three times higher in foxes ≥2 years of age (p = 0.026), indicating cumulative exposure with age. While Arctic foxes are seldom harvested for human consumption, they serve as sentinel hosts of Trichinella spp., confirming the presence of the parasite in wildlife in the region.

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Arctic foxes can serve as sentinel species for food-borne parasites like Trichinella.

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This study is the first to identify Trichinella T6 in Canadian Arctic foxes.

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The prevalence of Trichinella spp. in Arctic foxes was higher than previously reported.

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Adult foxes were three times more likely to be infected with Trichinella spp. than young foxes.

Novel insights into serodiagnosis and epidemiology of Erysipelothrix rhusiopathiae, a newly recognized pathogen in muskoxen (Ovibos moschatus)

BACKGROUND

Muskoxen are a key species of Arctic ecosystems and are important for food security and socio-economic well-being of many Indigenous communities in the Arctic and Subarctic. Between 2009 and 2014, the bacterium Erysipelothrix rhusiopathiae was isolated for the first time in this species in association with multiple mortality events in Canada and Alaska, raising questions regarding the spatiotemporal occurrence of the pathogen and its potential impact on muskox populations.

MATERIALS AND METHODS

We adapted a commercial porcine E. rhusiopathiae enzyme-linked immunosorbent assay to test 958 blood samples that were collected from muskoxen from seven regions in Alaska and the Canadian Arctic between 1976 and 2017. The cut-off between negative and positive results was established using mixture-distribution analysis, a data-driven approach. Based on 818 samples for which a serological status could be determined and with complete information, we calculated trends in sample seroprevalences in population time-series and compared them with population trends in the investigated regions.

RESULTS

Overall, 219/818 (27.8%, 95% Confidence Interval: 24.7-31.0) samples were classified as positive for exposure to E. rhusiopathiae. There were large variations between years and regions. Seropositive animals were found among the earliest serum samples tested; 1976 in Alaska and 1991 in Canada. In Alaskan muskoxen, sample seroprevalence increased after 2000 and, in two regions, peak seroprevalences occurred simultaneously with population declines. In one of these regions, concurrent unusual mortalities were observed and E. rhusiopathiae was isolated from muskox carcasses. In Canada, there was an increase in sample seroprevalence in two muskox populations following known mortality events that had been attributed to E. rhusiopathiae.

CONCLUSION

Our results indicate widespread exposure of muskoxen to E. rhusiopathiae in western Canada and Alaska. Although not new to the Arctic, we documented an increased exposure to the pathogen in several regions concurrent with population declines. Understanding causes for the apparent increased occurrence of this pathogen and its association with large scale mortality events for muskoxen is critical to evaluate the implications for wildlife and wildlife-dependent human populations in the Arctic.

Global plant trait relationships extend to the climatic extremes of the tundra biome

The majority of variation in six traits critical to the growth, survival and reproduction of plant species is thought to be organised along just two dimensions, corresponding to strategies of plant size and resource acquisition. However, it is unknown whether global plant trait relationships extend to climatic extremes, and if these interspecific relationships are confounded by trait variation within species. We test whether trait relationships extend to the cold extremes of life on Earth using the largest database of tundra plant traits yet compiled. We show that tundra plants demonstrate remarkably similar resource economic traits, but not size traits, compared to global distributions, and exhibit the same two dimensions of trait variation. Three quarters of trait variation occurs among species, mirroring global estimates of interspecific trait variation. Plant trait relationships are thus generalizable to the edge of global trait-space, informing prediction of plant community change in a warming world.

Muskox status, recent variation, and uncertain future

Muskoxen (Ovibos moschatus) are an integral component of Arctic biodiversity. Given low genetic diversity, their ability to respond to future and rapid Arctic change is unknown, although paleontological history demonstrates adaptability within limits. We discuss status and limitations of current monitoring, and summarize circumpolar status and recent variations, delineating all 55 endemic or translocated populations. Acknowledging uncertainties, global abundance is ca 170 000 muskoxen. Not all populations are thriving. Six populations are in decline, and as recently as the turn of the century, one of these was the largest population in the world, equaling ca 41% of today's total abundance. Climate, diseases, and anthropogenic changes are likely the principal drivers of muskox population change and result in multiple stressors that vary temporally and spatially. Impacts to muskoxen are precipitated by habitat loss/degradation, altered vegetation and species associations, pollution, and harvest. Which elements are relevant for a specific population will vary, as will their cumulative interactions. Our summaries highlight the importance of harmonizing existing data, intensifying long-term monitoring efforts including demographics and health assessments, standardizing and implementing monitoring protocols, and increasing stakeholder engagement/contributions.

Reproductive and genetic consequences of extreme isolation in Salix herbacea L. at the rear edge of its distribution

BACKGROUND AND AIMS

At the rear edge of the distribution of species, extreme isolation and small population size influence the genetic diversity and differentiation of plant populations. This may be particularly true for Arctic-alpine species in mid-latitude mountains, but exactly how peripherality has shaped their genetic and reproductive characteristics is poorly investigated. The present study, focused on Salix herbacea, aims at providing new insights into the causes behind ongoing demographic dynamics and their consequences for peripheral populations of Arctic-alpine species.

METHODS

We performed a whole-population, highly detailed sampling of the only two S. herbacea populations in the northern Apennines, comparing their clonal and genetic diversity, sex ratio and spatial genetic structure with a reference population from the Alps. After inspecting ~1800 grid intersections in the three populations, 563 ramets were genotyped at 11 nuclear microsatellite markers (nSSRs). Past demography and mating patterns of Apennine populations were investigated to elucidate the possible causes of altered reproductive dynamics.

KEY RESULTS

Apennine populations, which experienced a Holocene bottleneck and are highly differentiated (FST = 0.15), had lower clonal and genetic diversity compared with the alpine population (RMLG = 1 and HE = 0.71), with the smaller population exhibiting the lowest diversity (RMLG = 0.03 and HE = 0.24). An unbalanced sex ratio was found in the larger (63 F:37 M) and the smaller (99 F:1 M) Apennine population. Both were characterized by the presence of extremely large clones (up to 2500 m2), which, however, did not play a dominant role in local reproductive dynamics.

CONCLUSIONS

Under conditions of extreme isolation and progressive size reduction, S. herbacea has experienced an alteration of genetic characteristics produced by the prevalence of clonal growth over sexual reproduction. However, our results showed that the larger Apennine population has maintained levels of sexual reproduction enough to counteract a dramatic loss of genetic and clonal diversity.

A Transdisciplinary Approach to Brucella in Muskoxen of the Western Canadian Arctic 1989-2016

Brucella serostatus was evaluated in 3189 muskoxen sampled between 1989 and 2016 from various locations of the Canadian Arctic archipelago and mainland, near the communities of Sachs Harbour and Ulukhaktok, Northwest Territories, and Cambridge Bay and Kugluktuk, Nunavut. Brucella antibodies were found only in muskoxen sampled around Cambridge Bay, both on southern Victoria Island and on the adjacent mainland (Kent Peninsula). Consistent with participatory epidemiology data documented from local harvesters describing increased Brucella-like syndromes (swollen joints and lameness) and a decreased proportion of juveniles, the apparent Brucella seroprevalence in the sampled muskoxen of the Cambridge Bay area increased from 0.9% (95% CI 0.3-2.1) in the period of 1989-2001 to 5.6% (95% CI 3.3-8.9) in 2010-2016. The zoonotic bacteria Brucella suis biovar 4 was also cultured from tissues of muskoxen sampled on Victoria Island near Ulukhaktok in 1996 (n = 1) and Cambridge Bay in 1998, 2014, and 2016 (n = 3). Overall, our data demonstrate that B. suis biovar 4 is found in muskoxen that are harvested for food and by guided hunts on Victoria Island and Kent Peninsula, adding an important public health dimension to this study. Robust participatory epidemiology data on muskox health and diseases greatly enhanced the interpretation of our Cambridge Bay data and, combined with the serological and microbiological data, provide compelling evidence that the prevalence of B. suis biovar 4 has increased in this area since the late 1990s. This study enhances the available knowledge on Brucella exposure and infection in muskoxen and provides an example of how scientific knowledge and local knowledge can work together to better understand disease status in wildlife.

Traditional plant functional groups explain variation in economic but not size-related traits across the tundra biome

AIM

Plant functional groups are widely used in community ecology and earth system modelling to describe trait variation within and across plant communities. However, this approach rests on the assumption that functional groups explain a large proportion of trait variation among species. We test whether four commonly used plant functional groups represent variation in six ecologically important plant traits.

LOCATION

Tundra biome.

TIME PERIOD

Data collected between 1964 and 2016.

MAJOR TAXA STUDIED

295 tundra vascular plant species.

METHODS

We compiled a database of six plant traits (plant height, leaf area, specific leaf area, leaf dry matter content, leaf nitrogen, seed mass) for tundra species. We examined the variation in species-level trait expression explained by four traditional functional groups (evergreen shrubs, deciduous shrubs, graminoids, forbs), and whether variation explained was dependent upon the traits included in analysis. We further compared the explanatory power and species composition of functional groups to alternative classifications generated using post hoc clustering of species-level traits.

RESULTS

Traditional functional groups explained significant differences in trait expression, particularly amongst traits associated with resource economics, which were consistent across sites and at the biome scale. However, functional groups explained 19% of overall trait variation and poorly represented differences in traits associated with plant size. Post hoc classification of species did not correspond well with traditional functional groups, and explained twice as much variation in species-level trait expression.

MAIN CONCLUSIONS

Traditional functional groups only coarsely represent variation in well-measured traits within tundra plant communities, and better explain resource economic traits than size-related traits. We recommend caution when using functional group approaches to predict tundra vegetation change, or ecosystem functions relating to plant size, such as albedo or carbon storage. We argue that alternative classifications or direct use of specific plant traits could provide new insights for ecological prediction and modelling.

Assessment of climate change effects on mountain ecosystems through a cross-site analysis in the Alps and Apennines

Mountain ecosystems are sensitive and reliable indicators of climate change. Long-term studies may be extremely useful in assessing the responses of high-elevation ecosystems to climate change and other anthropogenic drivers from a broad ecological perspective. Mountain research sites within the LTER (Long-Term Ecological Research) network are representative of various types of ecosystems and span a wide bioclimatic and elevational range. Here, we present a synthesis and a review of the main results from ecological studies in mountain ecosystems at 20 LTER sites in Italy, Switzerland and Austria covering in most cases more than two decades of observations. We analyzed a set of key climate parameters, such as temperature and snow cover duration, in relation to vascular plant species composition, plant traits, abundance patterns, pedoclimate, nutrient dynamics in soils and water, phenology and composition of freshwater biota. The overall results highlight the rapid response of mountain ecosystems to climate change, with site-specific characteristics and rates. As temperatures increased, vegetation cover in alpine and subalpine summits increased as well. Years with limited snow cover duration caused an increase in soil temperature and microbial biomass during the growing season. Effects on freshwater ecosystems were also observed, in terms of increases in solutes, decreases in nitrates and changes in plankton phenology and benthos communities. This work highlights the importance of comparing and integrating long-term ecological data collected in different ecosystems for a more comprehensive overview of the ecological effects of climate change. Nevertheless, there is a need for (i) adopting co-located monitoring site networks to improve our ability to obtain sound results from cross-site analysis, (ii) carrying out further studies, in particular short-term analyses with fine spatial and temporal resolutions to improve our understanding of responses to extreme events, and (iii) increasing comparability and standardizing protocols across networks to distinguish local patterns from global patterns.

Qiviut cortisol in muskoxen as a potential tool for informing conservation strategies

Muskoxen (Ovibos moschatus) are increasingly subject to multiple new stressors associated with unprecedented climate change and increased anthropogenic activities across much of their range. Hair may provide a measurement of stress hormones (glucocorticoids) over periods of weeks to months. We developed a reliable method to quantify cortisol in the qiviut (wooly undercoat) of muskoxen using liquid chromatography coupled to tandem mass spectrometry. We then applied this technique to determine the natural variability in qiviut cortisol levels among 150 wild muskoxen, and to assess differences between sexes, seasons and years of collection. Qiviut samples were collected from the rump of adult muskoxen by subsistence and sport hunters in seven different locations in Nunavut and the Northwest Territories between 2013 and 2016. Results showed a high inter-individual variability in qiviut cortisol concentrations, with levels ranging from 3.5 to 48.9 pg/mg (median 11.7 pg/mg). Qiviut cortisol levels were significantly higher in males than females, and varied seasonally (summer levels were significantly lower than in fall and winter), and by year (levels significantly increased from 2013 to 2015). These differences may reflect distinct environmental conditions and the diverse stressors experienced, as well as physiological and/or behavioural characteristics. Quantification of qiviut cortisol may serve as a valuable tool for monitoring health and informing conservation and management efforts.

Microscale localized spectroscopy with a magnetic resonance force microscope

Magnetic resonance force microscopy is combined with spin-echo spectroscopy to obtain spatially and spectrally resolved NMR signals of micrometer-scale objects. The experimental spatial resolution for the demonstration experiment on a sample consisting of Ba(ClO3)2.H2O and (NH4)2SO4 single crystals is 3.4 microm. The spectral resolution of 3.4 kHz is sample limited. Improvements in resolution and extensions of the method to more than one spatial dimension and to multidimensional spectroscopy are possible.

Tunneling-induced spin alignment at low and zero field

The transfer of rotational to spin angular momentum of CH3 groups according to the Haupt effect is shown to be independent of magnetic field strength, including zero field. Haupt enhanced pulsed nuclear resonance signals of gamma-picoline have been observed at fields below 50 mT with a sensitivity enhancement of more than 3 orders of magnitude over thermally polarized experiments.

Manipulation of the director in bicellar mesophases by sample spinning: a new tool for NMR spectroscopy

It is shown that bicellar nematic liquid-crystalline phases can be oriented with the director (the normal to the bicellar plane) at an arbitrary angle to the applied magnetic field by sample rotation around one axis (variable-angle sample spinning) or around two axes successively (switched-angle spinning). This promises to open novel possibilities for NMR studies of bicelles and proteins incorporated into bicelles or dissolved in a solution containing bicelles, including the correlation of several orientations in a two-dimensional NMR experiment.

Electron spin density distribution in the polymer phase of CsC60: assignment of the NMR spectrum

We present high resolution 133Cs-13C double resonance NMR data and 13C-13C NMR correlation spectra of 13C enriched samples of the polymeric phase of CsC60. These data lead to a partial assignment of the lines in the 13C NMR spectrum of CsC60 to the carbon positions on the C60 molecule. A plausible completion of the assignment can be made on the basis of an ab initio calculation. The data support the view that the conduction electron density is concentrated at the C60 "equator," away from the interfullerene bonds.

Effect of modifications of the alkylpiperazine moiety of trazodone on 5HT2A and alpha1 receptor binding affinity

A series of triazolopyridine derivatives (compounds 2a-l) were synthesized in order to explore the effect of modifications of the alkylpiperazine moiety of trazodone (fragment A) on binding affinity for 5HT2A and alpha1 receptors. All of the synthesized compounds show a decrease of affinity for both 5HT2A and alpha1 receptors, as compared to trazodone, with the exception of compounds 2b,c which bear a methyl group in an alpha position to the aliphatic nitrogen atom N1. These compounds showed a decrease of affinity only for the alpha1 receptor. The stereochemical influence of the piperazine moiety of compound 2c was also evaluated. Enantiomer (S)-2c showed the most significant differences between 5HT2A and alpha1 receptor affinity (IC50 values) and among the corresponding functional properties (pA2 values). Since (S)-2c cannot generate the metabolite 4-(3-chlorophenyl)piperazine this product was selected for further pharmacological studies.

In situ NMR analysis of fluids contained in sedimentary rock

Limitations of resolution and absorption in standard chemical spectroscopic techniques have made it difficult to study fluids in sedimentary rocks. In this paper, we show that a chemical characterization of pore fluids may be obtained in situ by magic angle spinning (MAS) nuclear magnetic resonance (NMR), which is normally used for solid samples. 1H MAS-NMR spectra of water and crude oil in Berea sandstone show sufficient chemical shift resolution for a straightforward determination of the oil/water ratio. Copyright 1998 Academic Press.

Financial implications of noninvasive positive pressure ventilation (NPPV)

Noninvasive positive pressure ventilation (NPPV) is effective in the treatment of acute and chronic respiratory failure. However, the costs and financial balance between costs and diagnosis-related group (DRG) reimbursement for patients with moderate to severe respiratory failure treated with NPPV are unknown. We examined the costs and DRG reimbursement for 27 patients receiving Medicare referred with moderately severe respiratory failure for NPPV to the ventilator rehabilitation unit (VRU) at Temple University Hospital. This unit is one of four Health Care Financing Administration chronic ventilator-dependent demonstration sites that evaluates patients for NPPV, instructs them in home NPPV use, emphasizes rehabilitation, and uses strict cost accounting methods. Nineteen patients were treated with NPPV in the ICU and then referred to the VRU, and 8 patients were directly admitted for NPPV to the VRU. Patients were (mean +/- SE) 69 +/- 9 years age, 14 had severe COPD, and 13 had various restrictive disorders. All were hypercapneic at the time of hospital admission (restrictive 60 +/- 15; obstructive 67 +/- 3 mm Hg, PaCO2) with impaired lung mechanics and limited functional status. Patients averaged 8 +/- 15 days in the ICU, or 8 +/- 4.7 days on the medical floor prior to VRU transfer. The VRU length of stay averaged 20 +/- 18 days, for a total length of stay of 29 +/- 21 days. After implementation of NPPV, all patients had an improvement in gas exchange while spontaneously breathing and functional status that was maintained in follow-up. At 1 and 2 years of follow-up, 74% and 63% of patients were alive, respectively. Eleven patients were admitted with DRG 475 (respiratory system diagnosis with ventilator support); however, 16 of 27 patients were admitted across five different non-475 DRG codes with reimbursement rates ranging from $2,673 to $4,215. After DRG and outlier reimbursement, a total deficit of $261,948 remained (average deficit $9,701 per patient). However, individual patient deficits ranged from $1,113 to $32,892. Eighty-two percent of patients treated with NPPV incurred substantial financial losses that were underreimbursed across all assigned DRGs, including DRG 475, the highest-weighted DRG. We conclude that patients with moderate to severe respiratory failure receiving NPPV demonstrate an improvement in functional status and gas exchange that is maintained in follow-up. In addition, patients treated with NPPV incur high costs that are currently underreimbursed by the present DRG system. Newer DRG payment scales that recognize NPPV as specific treatment should be implemented.

Absolute bioavailability and absorption characteristics of aerosolized tobramycin in adults with cystic fibrosis

Administration of antibiotics by the inhalational route has become part of standard protocols for treatment of and prophylaxis for Pseudomonal pneumonias in patients with cystic fibrosis. For tobramycin, however, limited data are available on the aerosol absorption patterns, and no absolute bioavailability data for tobramycin exist. The purpose of this study was to measure the absolute bioavailability and systemic absorption characteristics of tobramycin when administered in high doses by a nebulizer. Multiple serum concentrations of tobramycin were measured after administration of an intravenous dose (mean, 2.9 mg/kg every 6 hours) and after an inhalational dose (5.6 mg/kg over 1 hour). Inhalational doses were superimposed over the "tail" of a steady-state intravenous dose to improve the sensitivity of the assay procedure (Abbott-TDX). Absolute bioavailability (F) was determined from AUC ratios normalized for dose. Model-independent pharmacokinetic parameters (volume of distribution [Vss] and total clearance [CLt]) were determined for each subject. Absorption characteristics (absorption rate constant [Ka] and mean absorption time [MAT]) were assessed after calculation of the cumulative fraction of drug absorbed, amount of bioavailable drug, and percent remaining to be absorbed per unit time using the Loo-Riegelman method. Three men and three women completed the study, and all received concurrent doses of ceftazidime. Mean absolute bioavailability (+/- standard deviation) was 9.13% (+/- 3.82), and the rate of absorption into the systemic circulation was consistent with a zero-order model profile for all subjects. Mean absorption time values reflected a wide degree of subject variability and ranged from approximately 15 to 150 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Early complications in type 1 diabetes: central nervous system alterations preceded kidney abnormalities

Abnormalities of the central nervous system (CNS), as discerned by neuroelectrophysiological studies, and an impaired, charge-related, differential filtration of protein at kidney level as evaluated by selective protein clearance, have recently been shown in diabetes of short duration and without any apparent complication. In order to explore the time of appearance and possible correlations, CNS and kidney abnormalities have been evaluated in parallel both in short-term and long-standing type 1 diabetic subjects. Two groups of patients were studied: Group 1 (no. 15), with no previously known clinical sign of complications and less than 5 years from diagnosis; Group 2 (no. 15) with more than 10 years of disease and with or without clinical signs of diabetic complications. Twenty age and sex comparable normal subjects were included in the study (Group 3). Short-latency multimodal evoked potentials (visual-VEP, brainstem auditory-BAEP, median and tibial somatosensory m- and t-SEP) and charge and/or size selective protein clearances (albumin, anionic immunoglobulins, neutral/cationic immunoglobulins) were evaluated. In Group 1, 27% of patients showed neurophysiological abnormalities (P < 0.05 vs. Group 3) while one showed proteinuria. In Group 2, 60% of patients showed electrophysiological changes (P < 0.0001 vs. Group 3) while 67% showed abnormal charge or size selective proteinuria (P < 0.0001 vs. controls) with a significant association between the abnormalities of CNS and of charge selective proteinuria (P < 0.05). Thus, CNS abnormalities may be detected even in patients with diabetes of short duration and are later associated with subclinical kidney abnormalities. These findings stress the value of the multimodal evoked potential evaluation as a sensitive and early diagnostic approach to the study of diabetic complications.