Sereina M. Graber

Life history, cognition and the evolution of complex foraging niches.

Animal species that live in complex foraging niches have, in general, improved access to energy-rich and seasonally stable food sources. Because human food procurement is uniquely complex, we ask here which conditions may have allowed species to evolve into such complex foraging niches, and also how niche complexity is related to relative brain size. To do so, we divided niche complexity into a knowledge-learning and a motor-learning dimension. Using a sample of 78 primate and 65 carnivoran species, we found that two life-history features are consistently correlated with complex niches: slow, conservative development or provisioning of offspring over extended periods of time. Both act to buffer low energy yields during periods of learning, and may thus act as limiting factors for the evolution of complex niches. Our results further showed that the knowledge and motor dimensions of niche complexity were correlated with pace of development in primates only, and with the length of provisioning in only carnivorans. Accordingly, in primates, but not carnivorans, living in a complex foraging niche requires enhanced cognitive abilities, i.e., a large brain. The patterns in these two groups of mammals show that selection favors evolution into complex niches (in either the knowledge or motor dimension) in species that either develop more slowly or provision their young for an extended period of time. These findings help to explain how humans constructed by far the most complex niche: our ancestors managed to combine slow development (as in other primates) with systematic provisioning of immatures and even adults (as in carnivorans). This study also provides strong support for the importance of ecological factors in brain size evolution.

Shared microbiome in gums and the lung in an outpatient population

OBJECTIVES Whether periopathogenic bacteria occur in the lung and gums simultaneously and what impact periodontitis has is unknown. METHODS In consecutive outpatients scheduled for bronchoscopies we performed a periodontal screening index. PCR to determine four periopathogens and seven less pathogenic species in both the periodontal pocket and bronchial protected specimen brush was used. Activated MMP8 in saliva and bronchial fluid was measured. RESULTS Periopathogens were detectable in gums and in the bronchial protected specimen brush in 75 (80%) and 27 (30%) of the cases, respectively. The concentration of activated MMP 8 was above 40 ng/ml in the saliva and in the bronchial fluid sample in six and 31 subjects, respectively. Significant agreement between the periodontal and bronchial compartment was found in three out of the four periopathogens. Patients with periopathogens in the lung suffered from periodontitis more frequently (p = 0.01). In patients with periopathogens detectable in the lung the concentration of aMMP8 tends to be more frequently above 40 ng/ml in the bronchial fluid (p = 0.09). CONCLUSIONS Agreement between periodontal and bronchial microbiome is more distinct for periopathogens than for less pathogenic species. Periodontitis itself represents a risk factor for pulmonary colonization with certain periopathogens. Pulmonary colonization with periopathogens seems to be associated with increased local inflammation.

Uptake of ferromagnetic carbon-encapsulated metal nanoparticles in endothelial cells: influence of shear stress and endothelial activation.

AIM Magnetic field guided drug targeting holds promise for more effective cancer treatment. Intravascular application of magnetic nanoparticles, however, bears the risk of potentially important, yet poorly understood side effects, such as off-target accumulation in endothelial cells. MATERIALS & METHODS Here, we investigated the influence of shear stress (0-3.22 dyn/cm(2)), exposure time (5-30 min) and endothelial activation on the uptake of ferromagnetic carbon-encapsulated iron carbide nanomagnets into endothelial cells in an in vitro flow cell model. RESULTS We found that even moderate shear stresses typically encountered in the venous system strongly reduce particle uptake compared with static conditions. Interestingly, a pronounced particle uptake was observed in inflamed endothelial cells. CONCLUSION This study highlights the importance of relevant exposure scenarios accounting for physiological conditions when studying particle-cell interactions as, for example, shear stress and endothelial activation are major determinants of particle uptake. Such considerations are of particular importance with regard to successful translation of in vitro findings into (pre-)clinical end points.

Late Post-Conditioning with Sevoflurane after Cardiac Surgery - Are Surrogate Markers Associated with Clinical Outcome?

Introduction In a recent randomized controlled trial our group has demonstrated in 102 patients that late post-conditioning with sevoflurane performed in the intensive care unit after surgery involving extracorporeal circulation reduced damage to cardiomyocytes exposed to ischemia reperfusion injury. On the first post-operative day the sevoflurane patients presented with lower troponin T values when compared with those undergoing propofol sedation. In order to assess possible clinical relevant long-term implications in patients enrolled in this study, we performed the current retrospective analysis focusing on cardiac and non-cardiac events during the first 6 months after surgery. Methods All patients who had successfully completed the late post-conditioning trial were included into this follow-up. Our primary and secondary endpoints were the proportion of patients experiencing cardiac and non-cardiac events, respectively. Additionally, we were interested in assessing therapeutic interventions such as initiation or change of drug therapy, interventional treatment or surgery. Results Of 102 patients analyzed in the primary study 94 could be included in this follow-up. In the sevoflurane group (with 41 patients) 16 (39%) experienced one or several cardiac events within 6 months after cardiac surgery, in the propofol group (with 53 patients) 19 (36%, p=0.75). Four patients (9%) with sevoflurane vs. 7 (13%) with propofol sedation had non-cardiac events (p=0.61). While a similar percentage of patients suffered from cardiac and/or non-cardiac events, only 12 patients in the sevoflurane group compared to 20 propofol patients needed a therapeutic intervention (OR: 0.24, 95% CI: 0.04-1.43, p=0.12). A similar result was found for hospital admissions: 2 patients in the sevoflurane group had to be re-admitted to the hospital compared to 8 in the propofol group (OR 0.23, 95% CI: 0.04-1.29, p=0.10). Conclusions Sevoflurane does not seem to provide protection with regard to the occurrence of cardiac and non-cardiac events in the 6-month period following cardiac surgery with the use of extracorporeal circulation. However, there was a clear trend towards fewer interventions (less need for treatment, fewer hospital admissions) associated with sevoflurane post-conditioning in patients experiencing any event. Such results might encourage launching large multicenter post-conditioning trials with clinical outcome defined as primary endpoint.

The Ecology of Social Learning in Animals and its Link with Intelligence

Classical ethology and behavioral ecology did not pay much attention to learning. However, studies of social learning in nature reviewed here reveal the near-ubiquity of reliance on social information for skill acquisition by developing birds and mammals. This conclusion strengthens the plausibility of the cultural intelligence hypothesis for the evolution of intelligence, which assumes that selection on social learning abilities automatically improves individual learning ability. Thus, intelligent species will generally be cultural species. Direct tests of the cultural intelligence hypothesis require good estimates of the amount and kind of social learning taking place in nature in a broad variety of species. These estimates are lacking so far. Here, we start the process of developing a functional classification of social learning, in the form of the social learning spectrum, which should help to predict the mechanisms of social learning involved. Once validated, the categories can be used to estimate the cognitive demands of social learning in the wild.

Significant improvement of olfactory performance in sleep apnea patients after three months of nasal CPAP therapy – Observational study and randomized trial

Objectives The olfactory function highly impacts quality of life (QoL). Continuous positive airway pressure is an effective treatment for obstructive sleep apnea (OSA) and is often applied by nasal masks (nCPAP). The influence of nCPAP on the olfactory performance of OSA patients is unknown. The aim of this study was to assess the sense of smell before initiation of nCPAP and after three months treatment, in moderate and severe OSA patients. Methods The sense of smell was assessed in 35 patients suffering from daytime sleepiness and moderate to severe OSA (apnea/hypopnea index ≥ 15/h), with the aid of a validated test battery (Sniffin’ Sticks) before initiation of nCPAP therapy and after three months of treatment. Additionally, adherent subjects were included in a double-blind randomized three weeks CPAP-withdrawal trial (sub-therapeutic CPAP pressure). Results Twenty five of the 35 patients used the nCPAP therapy for more than four hours per night, and for more than 70% of nights (adherent group). The olfactory performance of these patients improved significantly (p = 0.007) after three months of nCPAP therapy. When considering the entire group of patients, olfaction also improved significantly (p = 0.001). In the randomized phase the sense of smell of six patients deteriorated under sub-therapeutic CPAP pressure (p = 0.046) whereas five patients in the maintenance CPAP group showed no significant difference (p = 0.501). Conclusions Olfactory performance improved significantly after three months of nCPAP therapy in patients suffering from moderate and severe OSA. It seems that this effect of nCPAP is reversible under sub-therapeutic CPAP pressure. Trial registration ISRCTN11128866

Impact of intraoperative fluid administration on outcome in patients undergoing robotic-assisted laparoscopic prostatectomy – a retrospective analysis

BackgroundRobotic-assisted laparoscopic prostatectomy (RALP) gained much popularity during the last decade. Although the influence of intraoperative fluid management on patients’ outcome has been largely discussed in general, its impact on perioperative complications and length of hospitalization in patients undergoing RALP has not been examined so far. We hypothesized that a more restrictive fluid management might lead to a shortened length of hospitalization and a decreased rate of complications in our patients.MethodsRetrospective analysis of data of 182 patients undergoing RALP at an University Hospital (first series of RALP performed at the center).ResultsThe amount of fluid administered was initially normalized for body mass index of the patient and the duration of the operation and additionally corrected for age and the interaction of these variables. The application of crystalloids (multiple linear regression model, estimate = -0.044, p = 0.734) had no effect on the length of hospitalization, whereas a negative effect was found for colloids (estimate = -8.317, p = 0.021). Additionally, a significant interaction term between age and the amount of colloid applied (estimate = 0.129, p = 0.028) was calculated. Evaluation of the influence of intraoperative fluid administration using multiple logistic regression models corrected for body mass index, duration of the surgery and additionally for age revealed a negative effect of crystalloids on the incidence of an anastomotic leak between bladder and urethra (estimate = -23.860, p = 0.017), with a significant interaction term between age and the amount of crystalloids (estimate = 0.396, p = 0.0134). Colloids had no significant effect on this particular complication (estimate = 1.887, p = 0.524). Intraoperative blood loss did not alter the incidence of an anastomotic leak (estimate = 0.001, p = 0.086), nor did it affect the length of hospitalization (estimate = 0.0001, p = 0.351).ConclusionsIn accordance to the findings of our study, we suggest that a standardized, more restrictive fluid management might be beneficial in patients undergoing RALP. In older patients this measure would be able to shorten the length of hospitalization and to decrease the incidence of anastomosis leakage as a major complication.

Geographical Origin, Delayed Implantation, and Induced Ovulation Explain Reproductive Seasonality in the Carnivora:

Patterns of reproductive seasonality in the Carnivora are difficult to study comparatively, due to limited numbers of species for which information is available. Long-term databases of captive populations could overcome this difficulty. We apply a categorical description and a quantitative high-resolution measure (birth peak breadth, the number of days in which 80% of all births occur) based on daily observations in captivity to characterize the degree of reproductive seasonality in the Carnivora for 114 species with on average 1357 births per species. We find that the majority of species retained the birth seasonality displayed in the wild. Latitude of natural origin, delayed implantation, and induced ovulation were the main factors influencing reproductive seasonality. Most species were short-day breeders, but there was no evidence of an absolute photoperiodic signal for the timing of mating or conception. The length of the gestation period (corrected for body mass) generally decreased with birth seasonality but increased in species with delayed implantation. Birth seasons become shorter with increasing latitude of geographical origin, likely because the length of the favorable season declines with increasing latitude, exerting a strong selective pressure on fitting both the reproductive cycle and the interval offspring needs for growth following the termination of parental care into the short time window of optimal environmental conditions. Species with induced ovulation exhibit a less seasonal reproductive pattern, potentially because mates do not have to meet during a short time window of a fixed ovulation. Seasonal species of Carnivora shorten their gestation period so reproduction can occur during the short time window of optimal environmental conditions. Alternatively, other Carnivora species lengthen their gestation periods in order to bridge long winters. Interestingly, this occurs not by decelerating intrauterine growth but by delaying implantation.

Elevated matrix metalloproteinase levels in bronchi infected with periodontopathogenic bacteria

Objectives To determine whether bronchial colonisations/infections with periodontopathogenic bacteria are associated with elevated inflammatory markers such as MMPs, interleukins and Tumor necrosis factor alpha in the bronchial fluid. Methods Periodontal status was assessed in consecutive outpatients planned for elective bronchoscopies, and PCR for periodontopathogenic bacteria was performed from a protected specimen brush sample taken from the bronchial mucosa. Additionally, MMPs, interleukins and Tumor necrosis factor alpha were measured in the bronchial fluid. Results Out of the four species assessed, one species was found in 13 of 91 (14%) patients, and two in 12 (13%), three in 13 (14%) and all four in 1 (1%) patient, respectively. In multiple linear regression models the presence of Treponema denticola showed a consistent pattern of positive effects in bronchial fluid (Bonferroni adjusted p-values) on the levels of MMP9 (p adj.: 0.028) and MMP12 (p adj.: 0.029). Active smoking was independently associated with increased levels of aMMP8 (p adj.: 0.005) and MMP9 (p adj.: 0.009). Levels of IL-1 ß, IL-8 and Tumor necrosis factor alpha measured in the bronchial fluid were not affected by the presence of periodontopathogenic bacteria. Conclusions Bronchial colonisation/infection with Treponema denticola and smoking are independently associated with elevated MMPs (MMP9/MMP12 and MMP8/MMP9, respectively) in the bronchial fluid.

Comparing Two Imaging Methods for Follow-up of Lung Cancer Treatment: A Randomized Pilot Study

BACKGROUND Scientific data on the image modality to be used in postcurative treatment surveillance of non-small cell lung cancer patients are scarce. This prospective randomized pilot trial compared the performance of integrated 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) and contrast-enhanced computed tomography (CE-CT). METHODS After termination of curative-intent treatment, patients were randomly assigned to the PET-CT or the CE-CT group. Imaging was performed every 6 months for 2 years. If suspicious radiologic findings were detected or patients became symptomatic, a diagnostic workup was initiated. Sensitivity, specificity, and positive predictive value for detecting cancer recurrence were calculated for both imaging procedures. RESULTS The study enrolled 96 patients. In 14 of 50 patients (28%) in the PET-CT group and in 14 of 46 patients (30%) in the CE-CT group, a suspicious radiologic finding was confirmed as cancer recurrence after diagnostic workup. False-positive findings were detected in 11 patients (22%) of the PET-CT group and in 8 patients (17%) of the CE-CT group. The sensitivity, specificity, and positive predictive value for detecting cancer recurrence (95% confidence interval) were 0.88 (0.62 to 0.98), 0.62 (0.42 to 0.79), and 0.56 (0.35 to 0.76) for PET-CT and 0.93 (0.68 to 1.00), 0.72 (0.53 to 0.87), and 0.64 (0.41to 0.83) for CE-CT, respectively. CONCLUSIONS The results of our study suggest that PET-CT is not superior to CE-CT in detecting cancer recurrence during 2 years after curative-intent treatment of non-small cell lung cancer.