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Background: Pulmonary hypertension (PHT) is common in patients undergoing mitral valve surgery and is an independent risk factor for the development of acute right ventricular (RV) failure. Inhaled iloprost was shown to improve RV function and decrease RV afterload in patients with primary PHT. However, no randomized-controlled trials on the intraoperative use of iloprost in cardiac surgical patients are available. We therefore compared the effects of inhaled iloprost vs. intravenous standard therapy in cardiac surgical patients with chronic PHT. Methods: Twenty patients with chronic PHT undergoing mitral valve repair were randomized to receive inhaled iloprost (25 microg) or intravenous nitroglycerine. Iloprost was administered during weaning from cardiopulmonary bypass (CPB). Systemic and pulmonary haemodynamics were assessed with pulmonary artery catheterization and transoesophageal echocardiography. Milrinone and/or inhaled nitric oxide were available as rescue medication in case of failure to wean from CPB. Results: Inhaled iloprost selectively decreased the pulmonary vascular resistance index after weaning from CPB (208 +/- 108 vs. 422 +/- 62 dyn.s/cm(5)/m(2), P<0.05), increased the RV-ejection fraction (29 +/- 3% vs. 22 +/- 5%, P<0.05), improved the stroke volume index (27 +/- 7 vs. 18 +/- 6 ml/m(2), P<0.05) and reduced the transpulmonary gradient (10 +/- 4 vs. 16 +/- 3 mmHg, P<0.05). In all patients receiving inhaled iloprost, weaning from CPB was successful during the first attempt. In contrast, three patients in the control group required re-institution of CPB and had to be weaned from CPB using rescue medication. Conclusions: In patients with pre-existing PHT undergoing mitral valve surgery, inhaled iloprost is superior to intravenous nitrogylycerine by acting as a selective pulmonary vasodilator, reducing RV afterload and moderately improving RV-pump performance. [ABSTRACT FROM AUTHOR]

Background: In addition to their well-known ability to predict fluid responsiveness, functional pre-load parameters, such as the left ventricular stroke volume variation (SVV) and pulse pressure variation (PPV), have been proposed to allow real-time monitoring of cardiac pre-load. SVV and PPV result from complex heart–lung interactions during mechanical ventilation. It was hypothesized that, under open-chest conditions, when cyclic changes in pleural pressures during positive-pressure ventilation are less pronounced, functional pre-load indicators may be deceptive in the estimation of ventricular pre-load. Methods: Forty-five patients undergoing coronary artery bypass grafting participated in this prospective, observational study. PPV and SVV were assessed by pulse contour analysis. The thermodilution technique was used to measure the stroke volume index and global and right ventricular end-diastolic volume index. Trans-oesophageal echocardiography was used to determine the left ventricular end-diastolic area index. All parameters were assessed before and after sternotomy, and, in addition, after weaning from cardiopulmonary bypass before and after chest closure (pericardium left open). Patients were ventilated with constant tidal volumes (8 ± 2 ml/kg) throughout the study period using pressure control. Results: SVV and PPV decreased after sternotomy and increased after chest closure. However, these changes could not be related to concomitant changes in the ventricular pre-load. The stroke volume index was correlated with SVV and PPV in closed-chest conditions only, whereas volumetric indices reflected cardiac pre-load in both closed- and open-chest conditions. SVV and PPV were correlated with left and right ventricular pre-load in closed-chest–closed-pericardium conditions only (with the best correlation found for the right ventricular end-diastolic volume index). Conclusions: SVV and PPV may be misleading when estimating cardiac pre-load during open heart surgery. [ABSTRACT FROM AUTHOR]

Previous primate social network studies largely limited their focus to grooming and/or aggression networks, particularly among adult females. In addition, the consistency of individuals' network centrality across time and/or different networks has received little attention, despite this being critical for a global understanding of dynamic social structure. Here, we analyzed the grooming, aggression, and play social networks of a group of 26-28 wild vervet monkeys (Chlorocebus pygerythrus), including adults and juveniles, over two periods of 6 months. We collected data on grooming, play, and aggression using focal animal sampling with instantaneous recording and ad libitum sampling. We examined whether individuals' network centralities were consistent over the two periods and across networks, as well as the effect of age, sex, and dominance rank on three individual centrality metrics in each network and within each study period. We found that individuals were quite consistent in their network position from 1 year to the next despite changes in group composition. However, their network centralities were not correlated across networks, except for Strength and weighted Eigenvector centrality between grooming and aggression networks. We also found that in the aggression network, high-rankers showed the highest centrality in most network metrics (e.g., Degree, Strength, and Eigenvector centrality) and compared to males, females were most central in 2017 but not in 2018. In the grooming network, high-ranking females had the highest Eigenvector centrality, whereas in the play network, juvenile males had the highest Eigenvector centrality. Our findings corroborate previous findings on vervet monkeys. In addition, they show that individuals' network centralities may vary among networks and over time; thus highlighting the effect of sociodemographics and behaviors' functions on the group level dynamics of social behavior., (© 2021 Wiley Periodicals LLC.)

In social species, network centralities of group members shape social transmission and other social phenomena. Different factors have been found to influence the measurement of social networks, such as data collection and observation methods. In this study, we collected data on adults and juveniles and examined the effect of data collection method (ad libitum sampling vs. focal animal sampling) and observation method (interaction-grooming; play-vs. association-arm-length; 2 m; 5 m proximities-) on social networks in wild vervet monkeys. First, we showed using a bootstrapping method, that uncertainty of ad libitum grooming and play matrices were lesser than uncertainty of focal matrices. Nevertheless, grooming and play networks constructed from ad libitum and focal animal sampling were very similar and highly correlated. We improved the certainty of both grooming and play networks by pooling focal and ad libitum matrices. Second, we reported a high correlation between the proximity arm-length network and the focal grooming one making an arm-length proximity network a reasonable proxy for a grooming one in vervet monkeys. However, we did not find such a correlation between proximity networks and the play one. Studying the effects of methodological issues as data collection and observation methods can help improve understanding of what shapes social networks and which data collection method to choose to study sociality., (© 2020 Wiley Periodicals, Inc.)

Controlled laboratory experiments have delivered extensive and compelling evidence for the diffusion and maintenance of socially learned behavior in primates and other animals. Such evidence is rarer in the wild, but we show that a behavior seeded in a majority of individuals within vervet monkey (Chlorocebus pygerythus) groups may be sustained across several years. Here, we report results of two natural fission events in such groups that offer novel evidence of the resilience of socially transmitted group norms of behavior. Before fission, high ranked females exhibited an almost exclusive adherence to a group preference among two food options, originally introduced through a distasteful additive in one option, but no longer present in repeated later tests. Because of rank-dependent competition, low-ranked females ate more of the formerly distasteful food and so discovered it was now as palatable as the alternative. Despite this experience, low ranked females who formed the splinter groups then expressed a 100% bias for the preferred option of their original parent group, revealing these preferences to be resilient. We interpret this effect as conformity to either the preferences of high rankers or of a majority in the parent group, or both. However, given fissioned individuals' familiarity with their habitat and experimental options, we question the adequacy of the informational function usually ascribed to conformity and discuss alternatives under a concept of "social conformity"., (© 2017 Wiley Periodicals, Inc.)