Genetic and morphological divergence between Littorina fabalis ecotypes in Northern Europe

Low dispersal marine intertidal species facing strong divergent selective pressures associated with steep environmental gradients have a great potential to inform us about local adaptation and reproductive isolation. Among these, gastropods of the genus Littorina offer a unique system to study parallel phenotypic divergence resulting from adaptation to different habitats related with wave exposure. In this study, we focused on two Littorina fabalis ecotypes from Northern European shores and compared patterns of habitat‐related phenotypic and genetic divergence across three different geographic levels (local, regional and global). Geometric morphometric analyses revealed that individuals from habitats moderately exposed to waves usually present a larger shell size with a wider aperture than those from sheltered habitats. The phenotypic clustering of L. fabalis by habitat across most locations (mainly in terms of shell size) support an important role of ecology in morphological divergence. A genome scan based on amplified fragment length polymorphisms (AFLPs) revealed a heterogeneous pattern of differentiation across the genome between populations from the two different habitats, suggesting ecotype divergence in the presence of gene flow. The contrasting patterns of genetic structure between nonoutlier and outlier loci, and the decreased sharing of outlier loci with geographic distance among locations are compatible with parallel evolution of phenotypic divergence, with an important contribution of gene flow and/or ancestral variation. In the future, model‐based inference studies based on sequence data across the entire genome will help unravelling these evolutionary hypotheses, improving our knowledge about adaptation and its influence on diversification within the marine realm.     

Increases in serum concentration of human heart-type fatty acid-binding protein following elective coronary intervention

Background: Heart-type fatty acid-binding protein (H-FABP) is considered a marker of myocardial necrosis but whether or not it is modified by myocardial ischemia is not clear. We sought to investigate if H-FABP serum levels increase following non-urgent coronary angioplasty.

Methods: We studied 31 patients undergoing coronary angioplasty. Peripheral venous samples were drawn immediately before angioplasty, 1?h after the first balloon inflation and 24?h after the procedure and assayed for H-FABP.

Results: Serum levels of H-FABP increased significantly at 1?h vs baseline from 2554?±?1268 to 3322?±?245?pg?ml^?1 (p?=?0.024). However, no differences were observed between 1?h and 24?h after angioplasty (3268?±?1861 vs 3322?±?2459?pg ml^?1, p?=?0.87). Moreover, no significant difference was observed when we compared 24?h after angioplasty with the baseline (3268?±?1861vs 2554?±?1268?pg ml^?1, p?=?0.112).

Conclusions: We conclude that H-FABP significantly increases after elective coronary angioplasty at 1?h compared with baseline values; whether or not this has any prognostic significance for future events, as it occurs with troponins, needs to be studied further.     

Interspecific allometry for sexual shape dimorphism: Macroevolution of multivariate sexual phenotypes with application to Rensch's rule

Allometric trends in the degree of sexual dimorphism with body size have long fascinated evolutionary biologists. Many male-biased clades display more prominent sexual dimorphism in larger taxa (Rensch's rule), with most examples documenting this pattern for body size dimorphism. Although sexual dimorphism in traits other than body size is equally functionally relevant, characterizing allometric patterns of sexual dimorphism in such traits is hampered by lack of an analytical framework that can accommodate multivariate phenotypes. In this article, we derive a multivariate equivalency for investigating trends in sexual dimorphism—relative to overall body size—across taxa and provide a generalized test to determine whether such allometric patterns correspond with Rensch's rule. For univariate linear traits such as body size, our approach yields equivalent results to those from standard procedures, but our test is also capable of detecting trends in multivariate datasets such as shape. Computer simulations reveal that the method displays appropriate statistical properties, and an empirical example in Mediterranean lizards provides the first demonstration of Rensch's rule in a multivariate phenotype (head shape). Our generalized procedure substantially extends the analytical toolkit for investigating macroevolutionary patterns of sexual dimorphism and seeking a better understanding of the processes that underlie them.     

Death-related gastric necrosis after Laparoscopic Adjustable Gastric Banding in the early post-operative period

Background

Although mediastinal tumors compressing or invading the superior vena cava represent the major causes of the superior vena cava syndrome, benign processes may also be involved in the pathogenesis of this medical emergency. One of the rarest benign causes is a pseudoaneurysm developing in patients previously having heart surgery.

Case report

We present the case of a large pseudoaneurysm of the ascending aorta, five years after primary surgery, with a significant compression of the right mediastinal venous system causing superior vena cava syndrome, detected at chest CT angiography. Perioperative findings showed two rush out points both coming from the distal aortic suture line which was performed five years ago. The patient underwent reoperation under circulatory arrest facilitating safe exploration and repair of the distal anastomotic leaks

Conclusion

Enhanced chest CT should be always undertaken in all patients with superior vena cava syndrome, especially in those previously having cardiac or aortic surgery to correctly evaluate the presence of a pseudoaneurysm. Mass effect to the superior vena cava makes necessary an open surgical treatment of the pseudoaneurysm so as to concurrently resolve the right mediastinal venous system's compression. Surgery should be performed in terms of safe approach to avoid exsanguination and cerebral malperfusion.     

Stringent and reproducible tetracycline-regulated transgene expression by site-specific insertion at chromosomal loci with pre-characterised induction characteristics

Background  

The ability to regulate transgene expression has many applications, mostly concerning the analysis of gene function. Desirable induction characteristics, such as low un-induced expression, high induced expression and limited cellular heterogeneity, can be seriously impaired by chromosomal position effects at the site of transgene integration. Many clones may therefore need to be screened before one with optimal induction characteristics is identified. Furthermore, such screens must be repeated for each new transgene investigated, and comparisons between clones with different transgenes is complicated by their different integration sites.     

Observing the confinement potential of bacterial pore-forming toxin receptors inside rafts with nonblinking Eu(3+)-doped oxide nanoparticles

We track single toxin receptors on the apical cell membrane of MDCK cells with Eu-doped oxide nanoparticles coupled to two toxins of the pore-forming toxin family: α-toxin of Clostridium septicum and ε-toxin of Clostridium perfringens. These nonblinking and photostable labels do not perturb the motion of the toxin receptors and yield long uninterrupted trajectories with mean localization precision of 30 nm for acquisition times of 51.3 ms. We were thus able to study the toxin-cell interaction at the single-molecule level. Toxins bind to receptors that are confined within zones of mean area 0.40 ± 0.05 μm(2). Assuming that the receptors move according to the Langevin equation of motion and using Bayesian inference, we determined mean diffusion coefficients of 0.16 ± 0.01 μm(2)/s for both toxin receptors. Moreover, application of this approach revealed a force field within the domain generated by a springlike confining potential. Both toxin receptors were found to experience forces characterized by a mean spring constant of 0.30 ± 0.03 pN/μm at 37°C. Furthermore, both toxin receptors showed similar distributions of diffusion coefficient, domain area, and spring constant. Control experiments before and after incubation with cholesterol oxidase and sphingomyelinase show that these two enzymes disrupt the confinement domains and lead to quasi-free motion of the toxin receptors. Our control data showing cholesterol and sphingomyelin dependence as well as independence of actin depolymerization and microtubule disruption lead us to attribute the confinement of both receptors to lipid rafts. These toxins require oligomerization to develop their toxic activity. The confined nature of the toxin receptors leads to a local enhancement of the toxin monomer concentration and may thus explain the virulence of this toxin family.     

Relationships between head morphology, bite performance and ecology in two species of Podarcis wall lizards

Understanding the relationship between form and function is central to our comprehension of how phenotypic diversity evolves. Traits involved in multiple activities, such as social interactions and ecological resource use, are under the influence of different evolutionary forces potentially acting in opposite directions. Such systems provide the opportunity of understanding how potential constraints on morphological variation may influence whole-organism performance. In this study we examined morphology and bite performance in two closely related species of Podarcis wall lizards with divergent microhabitat preferences, to investigate how natural and sexual selection interact to shape the evolution of head traits. Our results show that although head morphology is markedly different between species and sexes, only sexes differ in bite force, indicating that the ecological differentiation between species is reflected in their morphology but does not constrain performance. Rather, the modification of the relative size of head components between species and a shift in the form-function relationship provide a potential explanation of how equal performance is attained by different morphological configurations. Geometric morphometrics provide a clear, biomechanically meaningful image of how this is achieved and show a bisexual pattern of head shape-bite force association in both species. This, together with a strong allometry of head size on body size and head shape on head size, provides indirect morphological evidence for the importance of sexual selection in shaping morphological and functional patterns. Finally, our findings suggest that the differences observed between species and sexes in head traits and bite performance are not reflected in their dietary ecology, implying that if trophic niche segregation between groups occurs, the reasons behind it are not primarily related to head morphology and functional variation.     

Unusual death due to a bleeding from a varicose vein: a case report

ABSTRACT: BACKGROUND: Varicose veins are a common entity presenting a worldwide distribution. Although they are usually benign, sometimes are proved to be a threatening condition. Massive hemorrhage is an unusual complication of this common venous pathology that demands immediate medical intervention. CASE PRESENTATION: We present a case of a 66-year-old woman found dead in her house surrounded by a large quantity of blood. Autopsy revealed a 7 mm ulcer on the internal surface of the left lower leg communicating with a varicose vein, signs of exsanguinations and liver cirrhosis. Toxicological analysis was negative. CONCLUSION: Massive hemorrhage from a ruptured varicosity is a severe medical emergency. Awareness of the risk of massive hemorrhage may provoke preventive treatment to be undertaken so as terminal loss of consciousness and a subsequent unattended death to be averted.     

Cilia‐localized LKB1 regulates chemokine signaling,macrophage recruitment,and tissue homeostasis in the kidney

Polycystic kidney disease (PKD) and other renal ciliopathies are characterized by cysts, inflammation, and fibrosis. Cilia function as signaling centers, but a molecular link to inflammation in the kidney has not been established. Here, we show that cilia in renal epithelia activate chemokine signaling to recruit inflammatory cells. We identify a complex of the ciliary kinase LKB1 and several ciliopathy‐related proteins including NPHP1 and PKD1. At homeostasis, this ciliary module suppresses expression of the chemokine CCL2 in tubular epithelial cells. Deletion of LKB1 or PKD1 in mouse renal tubules elevates CCL2 expression in a cell‐autonomous manner and results in peritubular accumulation of CCR2⁺ mononuclear phagocytes, promoting a ciliopathy phenotype. Our findings establish an epithelial organelle, the cilium, as a gatekeeper of tissue immune cell numbers. This represents an unexpected disease mechanism for renal ciliopathies and establishes a new model for how epithelial cells regulate immune cells to affect tissue homeostasis.