Sex-Specific associations of brain-derived neurotrophic factor and cardiorespiratory fitness in the general population

The brain-derived neurotrophic factor (BDNF) was initially considered to be neuron-specific. Meanwhile, this neurotrophin is peripherally also secreted by skeletal muscle cells and increases due to exercise. Whether BDNF is related to cardiorespiratory fitness (CRF) is currently unclear. We analyzed the association of serum BDNF levels with CRF in the general population (Study of Health in Pomerania (SHIP-TREND) from Northeast Germany; n = 1607, 51% female; median age 48 years). Sex-stratified linear regression models adjusted for age, height, smoking, body fat, lean mass, physical activity, and depression analyzed the association between BDNF and maximal oxygen consumption (VO2peak), maximal oxygen consumption normalized for body weight (VO2peak/kg), and oxygen consumption at the anaerobic threshold (VO2@AT). In women, 1mL/min higher VO2peak, VO2peak/kg, and VO2@AT were associated with a 2.43 pg/mL (95% confidence interval [CI]: 1.16 to 3.69 pg/mL; p = 0.0002), 150.66 pg/mL (95% CI: 63.42 to 237.90 pg/mL; p = 0.0007), and 2.68 pg/mL (95% CI: 0.5 to 4.8 pg/mL; p = 0.01) higher BDNF serum concentration, respectively. No significant associations were found in men. Further research is needed to understand the sex-specific association between CRF and BDNF. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Sex-Specific Associations of Brain-Derived Neurotrophic Factor and Cardiorespiratory Fitness in the General Population

The brain-derived neurotrophic factor (BDNF) was initially considered to be neuron-specific. Meanwhile, this neurotrophin is peripherally also secreted by skeletal muscle cells and increases due to exercise. Whether BDNF is related to cardiorespiratory fitness (CRF) is currently unclear. We analyzed the association of serum BDNF levels with CRF in the general population (Study of Health in Pomerania (SHIP-TREND) from Northeast Germany; n = 1607, 51% female; median age 48 years). Sex-stratified linear regression models adjusted for age, height, smoking, body fat, lean mass, physical activity, and depression analyzed the association between BDNF and maximal oxygen consumption (VO2peak), maximal oxygen consumption normalized for body weight (VO2peak/kg), and oxygen consumption at the anaerobic threshold (VO2@AT). In women, 1mL/min higher VO2peak, VO2peak/kg, and VO2@AT were associated with a 2.43 pg/mL (95% confidence interval [CI]: 1.16 to 3.69 pg/mL; p = 0.0002), 150.66 pg/mL (95% CI: 63.42 to 237.90 pg/mL; p = 0.0007), and 2.68 pg/mL (95% CI: 0.5 to 4.8 pg/mL; p = 0.01) higher BDNF serum concentration, respectively. No significant associations were found in men. Further research is needed to understand the sex-specific association between CRF and BDNF. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

The p.Arg435His Variation of IgG3 With High Affinity to FcRn Is Associated With Susceptibility for Pemphigus Vulgaris—Analysis of Four Different Ethnic Cohorts

IgG3 is the IgG subclass with the strongest effector functions among all four IgG subclasses and the highest degree of allelic variability among all constant immunoglobulin genes. Due to its genetic position, IgG3 is often the first isotype an antibody switches to before IgG1 or IgG4. Compared with the other IgG subclasses, it has a reduced half-life which is probably connected to a decreased affinity to the neonatal Fc receptor (FcRn). However, a few allelic variants harbor an amino acid replacement of His435 to Arg that reverts the half-life of the resulting IgG3 to the same level as the other IgG subclasses. Because of its functional impact, we hypothesized that the p.Arg435His variation could be associated with susceptibility to autoantibody-mediated diseases like pemphigus vulgaris (PV) and bullous pemphigoid (BP). Using a set of samples from German, Turkish, Egyptian, and Iranian patients and controls, we were able to demonstrate a genetic association of the p.Arg435His variation with PV risk, but not with BP risk. Our results suggest a hitherto unknown role for the function of IgG3 in the pathogenesis of PV

Variation in rhinarium temperature indicates sensory specializations in placental mammals

The rhinarium, a specialized nose-tip characterized by an area of naked and wet skin around the nostrils, is a typical mammalian structure. The type and amount of innervation suggests a sensory role and morphological diversity implies so far unidentified species-specific functional specializations. Rhinaria also vary in temperature and this may be related to the functions of these sensory organs. We performed a comparative study on rhinarium temperature in order to learn more about possible correlations with phylogeny and ecology. We have concentrated on terrestrial carnivorans and large herbivores, but also investigated a number of other species, some of them lacking typical rhinaria. We used infrared (IR) thermography to determine nose skin temperatures from safe distances and without interfering with the animals’ behavior. In all groups studied, the temperature of the rhinarium/nose-tip decreased with decreasing ambient temperature. At all ambient temperatures, rhinarium temperature was lower, by 9–17 °C, in carnivorans compared to herbivores. Glires (rodents and lagomorphs), haplorrhine primates, and omnivorous Perisso- and Artiodactyla were intermediate. In strepsirrhine primates, rhinarium temperature was similar to ambient temperature. Our findings in Strepsirrhini are consistent with the hypothesis that their rhinaria have an indirect role in chemical communication. Warm rhinaria in herbivores suggest a tactile function, while the low skin temperatures on carnivoran rhinaria may make the skin particularly sensitive to warming

Harbor seals (Phoca vitulina) can perceive optic flow under water.

Optic flow, the pattern of apparent motion elicited on the retina during movement, has been demonstrated to be widely used by animals living in the aerial habitat, whereas underwater optic flow has not been intensively studied so far. However optic flow would also provide aquatic animals with valuable information about their own movement relative to the environment; even under conditions in which vision is generally thought to be drastically impaired, e. g. in turbid waters. Here, we tested underwater optic flow perception for the first time in a semi-aquatic mammal, the harbor seal, by simulating a forward movement on a straight path through a cloud of dots on an underwater projection. The translatory motion pattern expanded radially out of a singular point along the direction of heading, the focus of expansion. We assessed the seal's accuracy in determining the simulated heading in a task, in which the seal had to judge whether a cross superimposed on the flow field was deviating from or congruent with the actual focus of expansion. The seal perceived optic flow and determined deviations from the simulated heading with a threshold of 0.6 deg of visual angle. Optic flow is thus a source of information seals, fish and most likely aquatic species in general may rely on for e. g. controlling locomotion and orientation under water. This leads to the notion that optic flow seems to be a tool universally used by any moving organism possessing eyes

Sex-specific associations of cardiorespiratory fitness and galectin-3 in the general population

Aims Low cardiorespiratory fitness (CRF) is associated with greater mortality and morbidity. Galectin-3 (Gal-3) is a prognostic biomarker for fibrosis and heart failure. Gal-3 is also associated with a greater risk for cardiovascular mortality. Whether CRF is related with Gal-3 is unclear. The objective of this study was to assess the sex-specific associations of CRF and Gal-3 levels in the general population. Methods Gal-3 concentrations were determined using a sandwich enzyme immunoassay in the population-based Study of Health in Pomerania (SHIP-TREND-0). Sex-stratified linear regression models adjusted for age, current smoking status, and renal function were used. Individuals with left ventricular ejection fraction (LVEF) 99th percentile) were excluded. Results A total of n = 1515 participants with a median age of 49 (IQR: 39–60 years, 48% males) were included. In men, a 1 L/min greater VO2peak was significantly related to 0.50 ng/mL (95% CI −0.8068 to −0.1938, P < 0.01) less Gal-3. In males, a 1 mL/min/kg higher VO2peak adjusted for body weight was associated with −0.0286 ng/mL (95% CI −0.0052 to −0.0005, P = 0.02) less Gal-3. When VO2peak was adjusted for lean mass 1 mL/kg/min more was correlated with a −0.0022 ng/mL (95% CI −0.0043 to -0.0007, P = 0.04) less Gal-3. In women, VO2peak (β −0.2046 95% CI −0.6541 to 0.2449, P = 0.37) and VO2peak adjusted for lean mass (β −0.0019 95% CI −0.0421 to –0.0050, P = 0.12) were not related with Gal-3, whereas a 1 mL/min/kg higher VO2peak adjusted for body weight was significantly associated with a −0.0064 ng/mL lower Gal-3 (95% CI −0.0092 to -0.0035, P < 0.01). There were no differences between pre-menopausal and post-menopausal women. Conclusions VO2peak was associated with Gal-3 only in men, but VO2peak adjusted for body weight in women and men. Our results suggest that the adverse consequences of low CRF may be mediated by Gal-3. Further research is needed to understand the sex-specific association between CRF and Gal-3 and whether they are clinically relevant

Experimental setup for the determination of the threshold of heading perception from virtual optic flow and response behavior of the harbor seal.

<p>A The computer generated optic flow field was back-projected by a projector and via a mirror system onto an underwater projection screen installed inside a projection chamber. For a high-quality underwater projection, the water surface was calmed by an acrylic frame, and the experimental area in front of the projection chamber was shaded by a black curtain. Inside this area, the animal was stationing underwater in a hoop station with the eyes at 1.5 m distance to the projection. During trials, the experimenter (not displayed) stayed outside the experimental area in order to avoid giving secondary cues. Scale 0.5 m. B In a “no go”-trial, in which the superimposed cross matched the FOE, the animal had to touch the cross with its snout in order to be rewarded. C In a “go”-trial (compare with <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0103555#pone-0103555-g002" target="_blank">Figure 2</a>), in which the cross deviated by a pre-programmed angular distance from the FOE, the seal had to turn away from the projection screen and touch the hoop station with its snout.</p

Accuracy of heading perception of a harbor seal.

<p>The harbor seal's ability to detect deviations of the cross from the FOE (in %) is plotted as a function of the angular distance between FOE and cross (in deg). The threshold of heading perception, defined as the angular distance between FOE and cross (delta phi) that could be detected with a performance of 50%, was interpolated by fitting an exponential function to the data (black curve; r² = 0.99). The resulting threshold of 0.6 deg is indicated by a black arrow pointing to the x-axis. Numbers at the data points indicate the number of trials per angular distance. The seal's false alarm rate of 21.7% (N = 351) is indicated at an angular distance of 0 deg (closed circle).</p

Optic flow projection.

<p>A three dimensional cloud of dots was presented to the harbor seal on an underwater projection screen. The FOE of the optic flow field (white dot, dot not shown during experiments) could occur on 28 positions all covered by a ring-shaped mask (grey circle). A cross was superimposed on the optic flow field at a pre-programmed angular distance (delta phi) to the FOE and could either match (“no go”-trial) or deviate from the FOE (“go”-trial, illustrated in this figure).</p

Lung function reference values in different German populations

SummaryBackgroundSpirometry is a frequently performed lung function test and an important tool in medical surveillance examinations of pulmonary diseases. The interpretation of lung function relies on the comparison to reference values derived from a healthy population.The study aim was to compare the lung function data of three representative population-based German studies (Study of Health in Pomerania [SHIP-1], Cooperative Health Research in the Region of Augsburg [KORA-S3] and European Community Respiratory Health Survey Erfurt [ECRHS-I Erfurt]) with existing European spirometry reference values and to establish a new set of comprehensive German prediction equations.MethodsSpirometry was performed in 4133 participants of three population-based surveys using almost identical standardised methods. Current and former smokers, subjects with cardiopulmonary disorders or on medication with potential influence on lung function were excluded. Sex specific prediction equations were established by quantile regression analyses. Comparison was performed to existing European reference values.ResultsThe healthy reference sample consisted of 1302 (516 male) individuals, aged 20–80 years. Sex specific comprehensive prediction equations adjusted for age and height are provided. Significant differences were found in comparison to previous studies with pronounced lower values of the current population if applying historic prediction equations.ConclusionThe results contribute to the interpretation of lung function examination in providing a comprehensive set of spirometry reference values obtained in a large number of healthy volunteers. Whereas the differences in between the investigated studies are negligible, striking divergence was detected in comparison to historic and recent European spirometry prediction values