Infections can change social behaviour in multiple ways, with profound impacts on pathogen transmission. However, these impacts might depend on the type of behaviour, how sociality as a biological ...trait is defined (e.g. network degree vs. mean edge strength) and the type of social relationship between the interacting individuals.
We used the highly social common vampire bat Desmodus rotundus to test how an immune challenge by lipopolysaccharide (LPS) injections affects two different social behaviours and three alternate measures of sociality, and whether the LPS effect differs by kinship relationship.
Effects of sickness should be lower for social behaviours that bestow greater benefits to inclusive fitness, such as food sharing. As predicted, immune‐challenged bats experienced a greater reduction in allogrooming received than food sharing received.
Sickness effects might also depend on how a social interaction is defined (e.g. the number of grooming partners vs. the duration of grooming events). We predicted that sickness would impact both the number and duration of social encounters, but we only detected a decrease in the number of grooming partners.
Finally, sickness effects might vary with social relationship type. We predicted that sickness effects should be smaller for interactions among close kin. As expected, the immune challenge had smaller effects on mother–offspring interactions.
In conclusion, our results highlight the need to explicitly consider how the effects of sickness on social network structure can differ depending on the ‘who, what, and how’ of social interactions, because these factors are likely to influence how sickness behaviour alters pathogen transmission.
Sickness alters how animals behave and interact. These effects, however, can vary depending on who is observed, what social behaviour is observed and how social interactions are quantified.
The incidence of atrial fibrillation (AF) in patients older than 75 years of age is expected to increase, and its treatment remains challenging. This study evaluated the impact of age on the outcomes ...of surgical ablation of AF.
A retrospective review was performed of patients who underwent the Cox-maze IV procedure at a single institution between 2005 and 2017. The patients were divided into a younger (age <75 years, n = 548) and an elderly cohort (age ≥75 years, n = 148). Rhythm outcomes were assessed at 1 year and annually thereafter. Predictors of first atrial tachyarrhythmia (ATA) recurrence were determined using Fine–Gray regression, allowing for death as the competing risk.
The mean age of the elderly group was 78.5 ± 2.8 years. The majority of patients (423/696, 61%) had nonparoxysmal AF. The elderly patients had a lower body mass index (P < .001) and greater rates of hypertension (P = .011), previous myocardial infarction (P = .017), heart failure (P < .001), and preoperative pacemaker (P = .008). Postoperatively, the elderly group had a greater rate of overall major complications (23% vs 14%, P = .017) and 30-day mortality (6% vs 2%, P = .026). The percent freedom from ATAs and antiarrhythmic drugs was lower in the elderly patients at 3 (69% vs 82%, P = .030) and 4 years (65% vs 79%, P = .043). By competing risk analysis, the incidence of first ATA recurrence was greater in elderly patients (33% vs 20% at 5 years; Gray test, P = .005). On Fine–Gray regression adjusted for clinically relevant covariates, increasing age was identified as a predictor of ATAs recurrence (subdistribution hazard ratio, 1.03; 95% confidence interval, 1.02-1.05, P < .001).
The efficacy of the Cox-maze IV procedure was worse in elderly patients; however, the majority of patients remained free of ATAs at 5 years. The lower success rate in these greater-risk patients should be considered when deciding to perform surgical ablation.
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Bipolar radiofrequency (RF) clamps have been shown to be capable of reproducibly creating transmural lesions with a single ablation in animal models. Unfortunately in clinical experience the bipolar ...clamps have not been as effective and often require multiple ablations to create conduction block. This study created a new experimental model using fresh, cardioplegically arrested human hearts turned down for transplant to evaluate the performance of a nonirrigated bipolar RF clamp.
Nine human hearts turned down for transplant were harvested, and the Cox-Maze IV lesion set was performed with a nonirrigated bipolar RF clamp. In the first 7 hearts a single ablation was performed for each lesion. In the last 2 hearts a set of 2 successive ablations without unclamping were performed. The heart tissue was stained with 2,3,5-triphenyl-tetrazolium chloride. Each ablation lesion was cross-sectioned to assess lesion depth and transmurality.
A single ablation with the bipolar RF clamp resulted in 89% (469/529) of the histologic sections and 65% (42/65) of the lesions being transmural. Of the nontransmural sections, 92% occurred in areas with epicardial fat. Performing 2 successive ablations without unclamping resulted in 100% of the cross-sections (201/201) and lesions (25/25) being transmural.
A single ablation failed to create a transmural lesion 35% of the time, and this was associated with the presence of epicardial fat. Two successive ablations without unclamping resulted in 100% lesion transmurality using the bipolar RF clamp.
Valve selection in dialysis-dependent patients can be difficult because long-term survival is diminished and bleeding risks during anticoagulation treatment are greater in patients with renal ...failure. In this study we analyzed long-term outcomes of dialysis-dependent patients who underwent valve replacement to help guide optimal prosthetic valve type selection.
Dialysis-dependent patients who underwent aortic and/or mitral valve replacement at 3 institutions over 20 years were examined. The primary outcome was long-term survival. A Cox regression model was used to estimate survival according to 5 ages, presence of diabetes, and/or heart failure symptoms.
Four hundred twenty-three available patients were analyzed; 341 patients had biological and 82 had mechanical valves. Overall complication and 30-day mortality rates were similar between the groups. Thirty-day readmission rates for biological and mechanical groups were 15% (50/341) and 28% (23/82; P = .005). Five-year survival was 23% and 33% for the biological and mechanical groups, respectively. After adjusting for age, New York Heart Association (NYHA) class, and diabetes using a multivariable Cox regression model, survival was similar between groups (hazard ratio, 0.93; 95% confidence interval, 0.66-1.29; P = .8). A Cox regression model on the basis of age, diabetes, and heart failure, estimated that patients only 30 or 40 years old, with NYHA class I-II failure without diabetes had a >50% estimated 5-year survival (P < .001).
Dialysis-dependent patients who underwent valve replacement surgery had poor long-term survival. Young patients without diabetes or NYHA III or IV symptoms might survive long enough to justify placement of a mechanical valve; however, a biological valve is suitable for most patients.
Vocalizations are an important means to facilitate social interactions, but vocal communication may be affected by infections. While such effects have been shown for mate-attraction calls, other ...vocalizations that facilitate social contact have received less attention. When isolated, vampire bats produce contact calls that attract highly associated groupmates. Here, we test the effect of an immune challenge on contact calling rates of individually isolated vampire bats. Sickness behaviour did not appear to change call structure, but it decreased the number of contact calls produced. This effect could decrease contact with groupmates and augment other established mechanisms by which sickness reduces social encounters (e.g. mortality, lethargy and social withdrawal or disinterest).
Postoperative atrial fibrillation (POAF) is the most common complication after cardiac surgery, and is associated with increased morbidity and mortality. Inflammation has been implicated as an ...etiology of POAF. Mitochondrial DNA (mtDNA) has been shown to initiate inflammation. This study analyzed inflammatory mechanisms of POAF by evaluating mtDNA, neutrophils, and cytokines/chemokines in the pericardial fluid and blood after cardiac surgery.
Blood and pericardial fluid from patients who underwent coronary artery bypass or heart valve surgery, or both, were collected intraoperatively and at 4, 12, 24, and 48 hours postoperatively. Real-time polymerase chain reaction was used to quantify mtDNA in the pericardial fluid and blood. A Luminex (Luminex Corp, Austin, TX) assay was used to study cytokine and chemokine levels. Flow cytometry was used to analyze neutrophil infiltration and activation in the pericardial fluid.
Samples from 100 patients were available for analysis. Postoperatively, mtDNA and multiple cytokine levels were higher in the pericardial fluid versus blood. Patients who had POAF had significantly higher levels of mtDNA in the pericardial fluid compared with patients who did not (P < .001, area under the curve 0.74). There was no difference in the mtDNA concentration in the blood between the POAF group and non-POAF group (P = .897). Neutrophil concentration increased in the pericardial fluid over time from a baseline of 0.8% to 56% at 48 hours (P < .01).
The pericardial space has a high concentration of inflammatory mediators postoperatively. Mitochondrial DNA in the pericardial fluid was strongly associated with the development of POAF. This finding provides insight into a possible mechanism of inflammation that may contribute to POAF, and may offer novel therapeutic targets.
Current myocarditis guidelines do not advocate treatment to prevent myocardial injury and scar deposition in patients with myocarditis and normal left ventricular ejection fraction. We aimed to ...ascertain the utility of beta blockers, calcium channel blockers and antagonists of the renin–angiotensin system in ameliorating myocardial injury, scar formation and calcification in animal in vivo models of myocarditis. The project was prospectively registered with the PROSPERO database of systematic reviews (CRD42018089336). Primary outcomes (necrosis, fibrosis and calcification) were meta-analysed with random-effects modelling. 52 studies were systematically reviewed. Meta-analysis was performed compared with untreated controls. In each study, we identified all independent comparisons of treatment versus control groups. The pooled weighted mean difference (WMD) indicated treatment reduced necrosis by 16.9% (71 controlled analyses, 95% CI 13.2–20.7%;
P
< 0.001), however there was less evidence of an effect after accounting for publication bias. Treatment led to a 12.8% reduction in fibrosis (73 controlled analyses, 95% CI 7.6–18.0%;
P
< 0.001). After accounting for publication bias this was attenuated to 7.8% but remained significant. Treatment reduced calcification by 4.1% (28 controlled analyses, 95% CI 0.2–8.0%;
P
< 0.0395). We observed significant heterogeneity in effect size in all primary endpoints, which was predominantly driven by differences between drug categories. Beta blockers and angiotensin-converting enzyme (ACE) inhibitors were the only agents that were effective for both necrosis and fibrosis, while only ACE inhibitors had a significant effect on calcification. This study provides evidence for a role for ACE inhibitors and beta blockers to prevent myocardial injury and scar deposition in in vivo models of myocarditis. There is a need for further well-designed studies to assess the translational application of these treatments.
The purpose of this study was to determine the effects of chronic left atrial volume overload on atrial anatomy, hemodynamics, and electrophysiology using a titratable left ventriculoatrial shunt in ...a canine model.
Canines (n = 16) underwent implantation of a shunt between the left ventricle and the left atrium. Sham animals (n = 8) underwent a median sternotomy without a shunt. Atrial activation times and effective refractory periods were determined using 250-bipolar epicardial electrodes. Biatrial pressures, systemic pressures, left atrial and left ventricle diameters and volumes, atrial fibrillation inducibility, and durations were recorded at the initial and at 6-month terminal study.
Baseline shunt fraction was 46% ± 8%. The left atrial pressure increased from 9.7 ± 3.5 mm Hg to 13.8 ± 4 mm Hg (P < .001). At the terminal study, the left atrial diameter increased from a baseline of 2.9 ± 0.05 cm to 4.1 ± 0.6 cm (P < .001) and left ventricular ejection fraction decreased from 64% ± 1.5% to 54% ± 2.7% (P < .001). Induced atrial fibrillation duration (median, range) was 95 seconds (0-7200) compared with 0 seconds (0-40) in the sham group (P = .02). The total activation time was longer in the shunt group compared with the sham group (72 ± 11 ms vs 62 ± 3 ms, P = .003). The right atrial and not left atrial effective refractory periods were shorter in the shunt compared with the sham group (right atrial effective refractory period: 156 ± 11 ms vs 141 ± 11 ms, P = .005; left atrial effective refractory period: 142 ± 23 ms vs 133 ± 11 ms, P = .35).
This canine model of mitral regurgitation reproduced the mechanical and electrical remodeling seen in clinical mitral regurgitation. Left atrial size increased, with a corresponding decrease in left ventricle systolic function, and an increased atrial activation times, lower effective refractory periods, and increased atrial fibrillation inducibility. This model provides a means to understand the remodeling by which mitral regurgitation causes atrial fibrillation.
Postamputation phantom pain is notoriously persistent with few validated treatments. Cryoneurolysis involves the application of low temperatures to reversibly ablate peripheral nerves. The authors ...tested the hypothesis that a single cryoneurolysis treatment would decrease phantom pain 4 months later.
The authors enrolled patients with a lower-limb amputation and established phantom pain. Each received a single-injection femoral and sciatic nerve block with lidocaine and was subsequently randomized to receive either ultrasound-guided percutaneous cryoneurolysis or sham treatment at these same locations. The primary outcome was the change in average phantom pain intensity between baseline and 4 months as measured with a numeric rating scale (0 to 10), after which an optional crossover treatment was offered. Investigators, participants, and clinical staff were masked to treatment group assignment with the exception of the treating physician performing the cryoneurolysis, who had no subsequent participant interaction.
Pretreatment phantom pain scores were similar in both groups, with a median quartiles of 5.0 4.0, 6.0 for active treatment and 5.0 4.0, 7.0 for sham. After 4 months, pain intensity decreased by 0.5 -0.5, 3.0 in patients given cryoneurolysis (n = 71) versus 0 0, 3 in patients given sham (n = 73), with an estimated difference (95% CI) of -0.1 (-1.0 to 0.7), P = 0.759. Following their statistical gatekeeping protocol, the authors did not make inferences or draw conclusions on secondary endpoints. One serious adverse event occurred after a protocol deviation in which a femoral nerve cryolesion was induced just below the inguinal ligament-instead of the sensory-only saphenous nerve-which resulted in quadriceps weakness, and possibly a fall and clavicle fracture.
Percutaneous cryoneurolysis did not decrease chronic lower extremity phantom limb pain 4 months after treatment. However, these results were based upon the authors' specific study protocol, and since the optimal cryoneurolysis treatment parameters such as freeze duration and anatomic treatment location remain unknown, further research is warranted.
Objective: To determine timing and risk factors associated with readmission within 30 days of discharge following noncardiac surgery. Background: Hospital readmission after noncardiac surgery is ...costly. Data on the drivers of readmission have largely been derived from single-center studies focused on a single surgical procedure with uncertainty regarding generalizability. Methods: We undertook an international (28 centers, 14 countries) prospective cohort study of a representative sample of adults ≥45 years of age who underwent noncardiac surgery. Risk factors for readmission were assessed using Cox regression (ClinicalTrials.gov, NCT00512109). Results: Of 36,657 eligible participants, 2744 (7.5%; 95% confidence interval CI, 7.2–7.8) were readmitted within 30 days of discharge. Rates of readmission were highest in the first 7 days after discharge and declined over the follow-up period. Multivariable analyses demonstrated that 9 baseline characteristics (eg, cancer treatment in past 6 months; adjusted hazard ratio HR, 1.44; 95% CI, 1.30–1.59), 5 baseline laboratory and physical measures (eg, estimated glomerular filtration rate or on dialysis; HR, 1.47; 95% CI, 1.24–1.75), 7 surgery types (eg, general surgery; HR, 1.86; 95% CI, 1.61–2.16), 5 index hospitalization events (eg, stroke; HR, 2.21; 95% CI, 1.24–3.94), and 3 other factors (eg, discharge to nursing home; HR, 1.61; 95% CI, 1.33–1.95) were associated with readmission. Conclusions: Readmission following noncardiac surgery is common (1 in 13 patients). We identified perioperative risk factors associated with 30-day readmission that can help frontline clinicians identify which patients are at the highest risk of readmission and target them for preventive measures.
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