Search

Pasture tracks are a modern equine housing trend often implemented as a weight control strategy due to the belief that they promote movement, though this is not proven experimentally. To test movement of horses housed in pasture tracks as compared to conventional pasture housing, two experiments were performed using a track (0.2ha, 3.5m in width, 561 m total distance) created around the perimeter of a 2.0 ha pasture. In experiment 1, eight horses were paired and rotated between three treatment locations: track (T), small 2 ha pasture housed within the track (SP), and a larger 20 ha pasture on the same farm (LP). A GPS-equipped watch attached to the crown piece of a halter tracked movement of horses over a ten-week study as they rotated in pairs to each location, with testing in all locations occurring simultaneously. Environmental impacts of housing were evaluated by comparing vegetative biomass and soil relocation throughout the study. In experiment 2, the same horses (n = 8) were rotated in isolated pairs to T or SP, with only one pair of horses tested at a time to ensure that social influences did not confound movement data. Collective results indicate that horses traveled approximately the same distance in T as compared to SP or LP. However, detrimental environmental impacts resulted from the track, including a decrease in vegetative biomass and greater sediment deposition from runoff. Potential environmental impacts should be further investigated to develop best management practices to mitigate erosion caused by pasture tracks., Competing Interests: Declaration of competing interest None of the authors have any financial or personal relationships that could inappropriately influence or bias the content of the paper., (Published by Elsevier Inc.)

White-tailed deer ( Odocoileus virginianus ) are highly susceptible to infection by SARS-CoV-2, with multiple reports of widespread spillover of virus from humans to free-living deer. While the recently emerged SARS-CoV-2 B.1.1.529 Omicron variant of concern (VoC) has been shown to be notably more transmissible amongst humans, its ability to cause infection and spillover to non-human animals remains a challenge of concern. We found that 19 of the 131 (14.5%; 95% CI: 0.10-0.22) white-tailed deer opportunistically sampled on Staten Island, New York, between December 12, 2021, and January 31, 2022, were positive for SARS-CoV-2 specific serum antibodies using a surrogate virus neutralization assay, indicating prior exposure. The results also revealed strong evidence of age-dependence in antibody prevalence. A significantly (χ 2 , p < 0.001) greater proportion of yearling deer possessed neutralizing antibodies as compared with fawns (OR=12.7; 95% CI 4-37.5). Importantly, SARS-CoV-2 nucleic acid was detected in nasal swabs from seven of 68 (10.29%; 95% CI: 0.0-0.20) of the sampled deer, and whole-genome sequencing identified the SARS-CoV-2 Omicron VoC (B.1.1.529) is circulating amongst the white-tailed deer on Staten Island. Phylogenetic analyses revealed the deer Omicron sequences clustered closely with other, recently reported Omicron sequences recovered from infected humans in New York City and elsewhere, consistent with human to deer spillover. Interestingly, one individual deer was positive for viral RNA and had a high level of neutralizing antibodies, suggesting either rapid serological conversion during an ongoing infection or a "breakthrough" infection in a previously exposed animal. Together, our findings show that the SARS-CoV-2 B.1.1.529 Omicron VoC can infect white-tailed deer and highlights an urgent need for comprehensive surveillance of susceptible animal species to identify ecological transmission networks and better assess the potential risks of spillback to humans., Key Findings: These studies provide strong evidence of infection of free-living white-tailed deer with the SARS-CoV-2 B.1.1.529 Omicron variant of concern on Staten Island, New York, and highlight an urgent need for investigations on human-to-animal-to-human spillovers/spillbacks as well as on better defining the expanding host-range of SARS-CoV-2 in non-human animals and the environment.

A comparison of allograft and autograft (pulmonary) replacement of the aortic valve has, to our knowledge, not been done in America. Fifty-seven patients (age range, 2 to 70 years; mean age, 30 years) underwent 59 operations for replacement of the aortic valve (20) or entire left ventricular outflow tract (39) using autograft (35) or allograft (24) valves. Many had undergone a previous operation (25) or had concomitant procedures (13). Postoperative mortality was 8.5% (5/59). Two deaths occurred in the allograft group and three in the more complex pulmonary autograft group. One late death occurred. One autograft was replaced with an allograft 7 months postoperatively for severe aortic regurgitation. There have been no episodes of either endocarditis or thromboembolism. Forty-nine of 51 survivors are in New York Heart Association class I. Preliminary results suggest that congenital or acquired disease of the left ventricular outflow tract and aortic valve can be safely and effectively treated with either allograft or autograft valve transplantation.

The effect of preoperative aortocoronary bypass grafting on the operative mortality of patients undergoing elective abdominal aortic reconstruction was examined by reviewing a series of 224 consecutive patients (1980 to 1983) (Group I) in whom selective preoperative noninvasive and invasive cardiac screening was used to identify patients with significant coronary stenoses. One patient died during cardiac catheterization. Twenty-seven patients (12 percent) underwent aortocoronary bypass grafting with one operative death (3.7 percent) and one nonfatal myocardial infarction (3.7 percent). These 26 patients subsequently underwent abdominal aortic reconstruction with no mortality and no postoperative myocardial infarction. One hundred ninety-six patients (88 percent) underwent aortic reconstruction without prior aortocoronary bypass grafting with four operative deaths (2 percent), including two fatal myocardial infarctions. The combined operative mortality for Group I patients was 2.3 percent. Three hundred twenty-six patients (Group II) who underwent abdominal aortic reconstruction at this institution from 1970 to 1976 had an 8 percent operative mortality, of which 50 percent of the deaths were due to myocardial infarctions (Group I versus Group II, p less than 0.01). Selective preoperative screening for coronary artery disease in patients undergoing elective abdominal aortic reconstruction with aortocoronary bypass grafting in selected patients is safe and may help reduce the operative mortality.

We compared multidose crystalloid hyperkalemic cardioplegic solutions with and without added red cells in 24 canine hearts subjected to 5 hr of arrest at 10 degrees C. All cardioplegic solutions were fully oxygenated at 4 degrees C before delivery. Since blood cardioplegia contained Ca++ carried over with the red cells, Ca++ was added to the crystalloid solution in one group. The table below shows the hematocrit (HCT) and ionized Ca++ concentrations of the cardioplegic solutions, and coronary arteriovenous oxygen difference during infusion of cardioplegic solution (AVO2) (ml O2/100 ml). Recovery during reperfusion is shown as percent of prearrest left ventricular function (LVF) and prearrest myocardial ATP concentration.

Two consecutive groups of high risk patients with left main coronary disease (greater than 50% stenosis) undergoing aortocoronary bypass grafting using different cardioplegia delivery methods were compared retrospectively for perioperative myocardial infarction (MI) and mortality. Group I (July 1979 to June 30, 1982, n = 53) received an initial 1000 ml aortic root cardioplegia infusion from a pressure regulated (85-100 mmHg) delivery system. Regional mid-myocardial wall temperatures determined the distal anastomoses sequence (with the warmest region bypassed first) followed by additional 400 ml cardioplegia infusions. Group II patients (March 1976 to June 30, 1979, n = 47) had their cardioplegia administered by a hand-held syringe without regional temperature mapping. The volume injected varied and was based on cessation of electrical activity or a septal temperature less than 20 degrees C. Background data were similar except that Group I was significantly older than Group II (63.4 +/- 1.4 years vs 57.1 +/- 1.5 years, p less than 0.01). Despite this, there was only 1 (2%) perioperative MI in Group I vs 6 (13%) in Group II (p less than 0.05). There was also a marked reduction in cardiac mortality with 1 (2%) cardiac death in Group I vs 5 (11%) in Group II (p = 0.09). These data suggest that the delivery of adequate volumes of cardioplegia, in conjunction with myocardial temperature directed bypass grafting, can improve myocardial preservation in high risk patients.

To examine the relationship between intramyocardial pH during global ischemic arrest and subsequent functional and biochemical recovery, 40 canine hearts were subjected to 4 hours of arrest at 10 degrees C. Four groups, each containing 10 hearts, were differentiated by the oxygen concentration of a hyperkalemic crystalloid cardioplegic solution (CCS), which was infused every 20 minutes. In group 1 the CCS was equilibrated at 4 degrees C with nitrogen to remove oxygen. In group 2 the CCS was aerated at 4 degrees C. In group 3 the CCS was treated to achieve an oxygen tension (PO2) similar to group 2 but with a reduced nitrogen content to prevent bubble formation, which is theoretically possible during reperfusion ("myocardial bends"). In group 4 the CCS was fully oxygenated at 4 degrees C. The resulting PO2 of CCS measured at 10 degrees C was less than 20, 170, 170, and 750 mm Hg in groups 1, 2, 3, and 4, respectively. Left ventricular function (LVF) was assessed from function curves at constant mean aortic pressure and heart rate. Functional recovery, expressed as a percentage of prearrest LVF, was 38.1% +/- 10.7% in group 1 and 84.0% +/- 8.1% in group 4 (p less than 0.008). Functional recovery was 64.9% +/- 5.5% and 69.1% +/- 7.0% in groups 2 and 3, which had similar PO2. Differences in recovery between groups 2 and 3 and group 1 approached statistical significance (p less than 0.05, NS). The mean-integrated intramyocardial pH during arrest was higher (p less than 0.003) in group 4 (7.14 +/- 0.05) than in group 1 (6.84 +/- 0.06) or group 2 (6.86 +/- 0.07). The minimum intramyocardial pH during arrest was higher in group 4 than in any other group (p less than 0.002). Myocardial adenosine triphosphate concentration at the end of arrest, expressed as a percentage of its prearrest value, was highest in group 4 (75.9% +/- 8.1%) and lowest in group 1 (54.3% +/- 5.7%), a difference approaching statistical significance (p less than 0.05, NS). These data suggest that the measurement of intramyocardial pH is a useful on-line indicator of the adequacy of preservation during hypothermic arrest and that excess nitrogen in aerated CCS had little or no effect on recovery. The data confirm the hypothesis that oxygenation of CCS is associated with good myocardial preservation, which may be attributed to the provision of oxygen for the support of aerobic metabolism during arrest.