Two-row, three-row or powered circular stapler, which to choose when performing colorectal anastomosis? A systematic review and meta-analysis.

PURPOSE: Three types of circular staplers can be used to perform a colorectal anastomosis: two-row (MCS), three-row (TRCS) and powered (PCS) devices. The objective of this meta-analysis has been to provide the existing evidence on which of these circular staplers would have a lower risk of presenting a leak (AL) and/or anastomotic bleeding (AB). METHODS: An in-depth search was carried out in the electronic bibliographic databases Embase, PubMed and SCOPUS. Observational studies were included, since randomized clinical trials comparing circular staplers were not found. RESULTS: In the case of AL, seven studies met the inclusion criteria in the PCS group and four in the TRCS group. In the case of AB, only four studies could be included in the analysis in the PCS group. The AL OR reported for PCS was 0.402 (95%-confidence interval (95%-CI): 0.266-0.608) and for AB: 0.2 (95% CI: 0.08-0.52). The OR obtained for AL in TRCS was 0.446 (95%-CI: 0.217 to 0.916). Risk difference for AL in PCS was - 0.06 (95% CI: - 0.07 to - 0.04) and in TRCS was - 0.04 (95%-CI: - 0.08 to - 0.01). Subgroup analysis did not report significant differences between groups. On the other hand, the AB OR obtained for PCS was 0.2 (95% CI: 0.08-0.52). In this case, no significant differences were observed in subgroup analysis. CONCLUSION: PCS presented a significantly lower risk of leakage and anastomotic bleeding while TRCS only demonstrated a risk reduction in AL. Risk difference of AL was superior in the PCS than in TRCS.

Histology of Convergent Probing Appendages in Mormyridae.

Mormyridae is an early diverging family of Teleostean fishes that produce an electric field for navigation and communication using an electric organ. This clade has a diverse array of soft-tissue rostral appendages, such as the chin-swelling, the Schnauzenorgan, and the tubesnout combined with a Schnauzenorgan, that have evolved multiple times. Here we assess if macroscopically convergent, soft-tissue rostral appendages are also histologically convergent. Further, we investigate how the histology of these appendages can inform their function. We sampled independent gains of the chin-swelling and Schnauzenorgan to understand similarities and differences in their anatomies. We show that macroscopically convergent rostral appendages are also convergent at a histological level, and different types of rostral appendages share a similar anatomy; that said, minor differences likely relate to their specific functions. Based on a comparison of the skeletal muscle distribution and the differing attachment shapes of each appendage to the dentary, we conclude that the Schnauzenorgan is capable of a wider range of movements than the chin swelling. Furthermore, the anatomy suggests that these soft-tissue rostral appendages likely function as electrosensory foveas (i.e., an appendage that focuses a sensory system). Lastly, these histological data support the hypothesis that the chin swelling may be a precursor to the Schnauzenorgan.

ResumenMormyridae es una de las primeras familias divergentes de peces teleósteos que producen un campo eléctrico para la navegación y la comunicación mediante un órgano eléctrico. Este clado tiene una variedad diversa de apéndices rostrales de tejidos blandos, como el mentón hinchado, el Schnauzenorgan y el hocico tubular combinado con un Schnauzenorgan, que han evolucionado varias veces. Aquí evaluamos si los apéndices rostrales de tejido blando macroscópicamente convergentes también son histológicamente convergentes. Además, investigamos cómo la histología de estos apéndices puede informar sus funciones. Tomamos muestras de ganancias independientes del mentón hinchado y del Schnauzenorgan para comprender las similitudes y diferencias en sus anatomías. Mostramos que los apéndices rostrales macroscópicamente convergentes también lo son a nivel histológico, y diferentes tipos de apéndices rostrales comparten una anatomía similar; dicho esto, es probable que las diferencias menores se relacionen con sus funciones específicas. Con base en una comparación de la distribución del músculo esquelético y las diferentes formas de unión de cada apéndice al dentario, concluimos que el Schnauzenorgan es capaz de realizar una gama más amplia de movimientos que el mentón hinchado. Además, la anatomía sugiere que estos apéndices rostrales de tejido blando probablemente funcionen como fóveas electrosensoriales (es decir, un apéndice que enfoca un sistema sensorial). Por último, estos datos histológicos apoyan la hipótesis de que el mentón hinchado puede ser un precursor del Schnauzenorgan.

Phylogenomics of Piranhas and Pacus (Serrasalmidae) Uncovers How Dietary Convergence and Parallelism Obfuscate Traditional Morphological Taxonomy.

The Amazon and neighboring South American river basins harbor the world's most diverse assemblages of freshwater fishes. One of the most prominent South American fish families is the Serrasalmidae (pacus and piranhas), found in nearly every continental basin. Serrasalmids are keystone ecological taxa, being some of the top riverine predators as well as the primary seed dispersers in the flooded forest. Despite their widespread occurrence and notable ecologies, serrasalmid evolutionary history and systematics are controversial. For example, the sister taxon to serrasalmids is contentious, the relationships of major clades within the family are inconsistent across different methodologies, and half of the extant serrasalmid genera are suggested to be non-monophyletic. We analyzed exon capture to reexamine the evolutionary relationships among 63 (of 99) species across all 16 serrasalmid genera and their nearest outgroups, including multiple individuals per species to account for cryptic lineages. To reconstruct the timeline of serrasalmid diversification, we time-calibrated this phylogeny using two different fossil-calibration schemes to account for uncertainty in taxonomy with respect to fossil teeth. Finally, we analyzed diet evolution across the family and comment on associated changes in dentition, highlighting the ecomorphological diversity within serrasalmids. We document widespread non-monophyly of genera within Myleinae, as well as between Serrasalmus and Pristobrycon, and propose that reliance on traits like teeth to distinguish among genera is confounded by ecological homoplasy, especially among herbivorous and omnivorous taxa. We clarify the relationships among all serrasalmid genera, propose new subfamily affiliations, and support hemiodontids as the sister taxon to Serrasalmidae. [Characiformes; exon capture; ichthyochory; molecular time-calibration; piscivory.].

An XROMM Study of Food Transport and Swallowing in Channel Catfish.

Most predatory ray-finned fishes swallow their food whole, which can pose a significant challenge, given that prey items can be half as large as the predators themselves. How do fish transport captured food from the mouth to the stomach? Prior work indicates that, in general, fish use the pharyngeal jaws to manipulate food into the esophagus, where peristalsis is thought to take over. We used X-Ray Reconstruction of Moving Morphology to track prey transport in channel catfish (Ictalurus punctatus). By reconstructing the 3D motions of both the food and the catfish, we were able to track how the catfish move food through the head and into the stomach. Food enters the oral cavity at high velocities as a continuation of suction and stops in the approximate location of the branchial basket before moving in a much slower, more complex path toward the esophagus. This slow phase coincides with little motion in the head and no substantial mouth opening or hyoid depression. Once the prey is in the esophagus, however, its transport is surprisingly tightly correlated with gulping motions (hyoid depression, girdle retraction, hypaxial shortening, and mouth opening) of the head. Although the transport mechanism itself remains unknown, to our knowledge, this is the first description of synchrony between cranial expansion and esophageal transport in a fish. Our results provide direct evidence of prey transport within the esophagus and suggest that peristalsis may not be the sole mechanism of esophageal transport in catfish.

Multiple Degrees of Freedom in the Fish Skull and Their Relation to Hydraulic Transport of Prey in Channel Catfish.

Fish perform many complex manipulation behaviors without hands or flexible muscular tongues, instead relying on more than 20 movable skeletal elements in their highly kinetic skulls. How fish use their skulls to accomplish these behaviors, however, remains unclear. Most previous mechanical models have represented the fish skull using one or more planar four-bar linkages, which have just a single degree of freedom (DoF). In contrast, truncated-cone hydrodynamic models have assumed up to five DoFs. In this study, we introduce and validate a 3D mechanical linkage model of a fish skull that incorporates the pectoral girdle and mandibular and hyoid arches. We validate this model using an in vivo motion dataset of suction feeding in channel catfish and then use this model to quantify the DoFs in the fish skull, to categorize the motion patterns of the cranial linkage during feeding, and to evaluate the association between these patterns and food motion. We find that the channel catfish skull functions as a 17-link, five-loop parallel mechanism. Despite having 19 potential DoFs, we find that seven DoFs are sufficient to describe most of the motion of the cranial linkage, consistent with the fish skull functioning as a multi-DoF, manipulation system. Channel catfish use this linkage to generate three different motion patterns (rostrocaudal wave, caudorostral wave, and compressive wave), each with its own associated food velocity profile. These results suggest that biomechanical manipulation systems must have a minimum number of DoFs to effectively control objects, whether in water or air.

Multifunctional Structures and Multistructural Functions: Integration in the Evolution of Biomechanical Systems.

Integration is an essential feature of complex biomechanical systems, with coordination and covariation occurring among and within structural components at time scales that vary from microseconds to deep evolutionary time. Integration has been suggested to both promote and constrain morphological evolution, and the effects of integration on the evolution of structure likely vary by system, clade, historical contingency, and time scale. In this introduction to the 2019 symposium "Multifunctional Structures and Multistructural Functions," we discuss the role of integration among structures in the context of functional integration and multifunctionality. We highlight articles from this issue of Integrative and Comparative Biology that explore integration within and among kinematics, sensory and motor systems, physiological systems, developmental processes, morphometric dimensions, and biomechanical functions. From these myriad examples it is clear that integration can exist at multiple levels of organization that can interact with adjacent levels to result in complex patterns of structural and functional phenotypes. We conclude with a synthesis of major themes and potential future directions, particularly with respect to using multifunctionality, itself, as a trait in evolutionary analyses.

The Role of Developmental Integration and Historical Contingency in the Origin and Evolution of Cypriniform Trophic Novelties.

While functional morphologists have long studied the evolution of anatomical structures, the origin of morphological novelties has received less attention. When such novelties first originate they must become incorporated into an integrated system to be rendered fully functional. Thus, developmental integration is key at the origin of morphological novelties. However, given enough evolutionary time such integration may be broken, allowing for a division of labor that is facilitated by subsequent decoupling of structures. Cypriniformes represent a diverse group of freshwater fishes characterized by several trophic novelties that include: kinethmoid-mediated premaxillary protrusion, a muscular palatal and post-lingual organ, hypertrophied lower pharyngeal jaws that masticate against the base of the neurocranium, novel pharyngeal musculature controlling movement of the hypertrophied lower pharyngeal jaws, and in a few species an incredibly complex epibranchial organ used to aggregate filtered phytoplankton. Here, we use the wealth of such trophic novelties in different cypriniform fishes to present case studies in which developmental integration allowed for the origin of morphological innovations. As proposed in case studies 1 and 2 trophic innovations may be associated with both morphological and lineage diversification. Alternatively, case studies 3 and 4 represent a situation where ecological niche was expanded but with no concomitant increase in species diversity.

Morphological and functional maturity of the oral jaws covary with offspring size in Trinidadian guppies.

Large size of individual offspring is routinely selected for in highly competitive environments, such as in low-predation populations of the Trinidadian guppy (Poecilia reticulata). Large guppy offspring outcompete their smaller conspecifics, but the functional mechanisms underlying this advantage are unknown. We measured jaw kinematics during benthic feeding and cranial musculoskeletal morphologies in neonates and juveniles from five populations of Trinidadian guppy and found that both kinematics and morphologies vary substantially with neonatal size. Rotation at the intramandibular joint (IMJ), but not the quadratomandibular joint (QMJ), increases with size among guppy offspring, from 11.7° in the smallest neonates to 22.9° in the largest neonates. Ossification of the cranial skeleton varies from 20% in the smallest neonates to 90% in the largest. Relative to standard length (SL; jaw tip to caudal fin base distance), the surface area of jaw-closing musculature scales with positive allometry (SL2.72) indicating that muscle growth outpaces body growth. Maximum gape also scales with positive allometry (SL1.20), indicating that larger neonates are capable of greater jaw excursions. These findings indicate that size is not the sole adaptive benefit to producing larger offspring; maturation provides a potential functional mechanism underlying the competitive advantage of large offspring size among Trinidadian guppies.

Distinct mechanisms regulate slow-muscle development.

Vertebrate muscle development begins with the patterning of the paraxial mesoderm by inductive signals from midline tissues [1, 2]. Subsequent myotome growth occurs by the addition of new muscle fibers. We show that in zebrafish new slow-muscle fibers are first added at the end of the segmentation period in growth zones near the dorsal and ventral extremes of the myotome, and this muscle growth continues into larval life. In marine teleosts, this mechanism of growth has been termed stratified hyperplasia [3]. We have tested whether these added fibers require an embryonic architecture of muscle fibers to support their development and whether their fate is regulated by the same mechanisms that regulate embryonic muscle fates. Although Hedgehog signaling is required for the specification of adaxial-derived slow-muscle fibers in the embryo [4, 5], we show that in the absence of Hh signaling, stratified hyperplastic growth of slow muscle occurs at the correct time and place, despite the complete absence of embryonic slow-muscle fibers to serve as a scaffold for addition of these new slow-muscle fibers. We conclude that slow-muscle-stratified hyperplasia begins after the segmentation period during embryonic development and continues during the larval period. Furthermore, the mechanisms specifying the identity of these new slow-muscle fibers are different from those specifying the identity of adaxial-derived embryonic slow-muscle fibers. We propose that the independence of early, embryonic patterning mechanisms from later patterning mechanisms may be necessary for growth.

Intraspecific scaling of feeding mechanics in an ontogenetic series of zebrafish, Danio rerio.

While a vast literature and long tradition of examining the scaling of locomotory function exists, scaling studies on feeding mechanics are relatively rare. A recent increase in research activity examining the scaling of feeding kinematics has led to conflicting results. These divergent findings may be due to the inherent differences in the biophysical systems being examined. The present study examines the role of growth in the scaling of feeding kinematics in an ontogenetic series of zebrafish, Danio rerio. Although many other studies have investigated aquatic feeding, this study represents the first to quantify detailed feeding kinematics in first-feeding larvae. This study examines both the effects of violating assumptions of geometric similarity when examining scaling relationships and the role water viscosity plays in molding scaling coefficients derived from feeding kinematics. The effects of Reynolds number, generally not relevant in vertebrate feeding studies, play a crucial role in determining scaling relationships in this species. Many scaling coefficients reflect the functional challenges of feeding at low Reynolds numbers. Moreover, scaling patterns in feeding mechanics often reflect allometric growth during early ontogeny. The advent of high-speed video recording (1000 frames s(-1)) now allows the kinematics of feeding at these small sizes to be rigorously examined.

Days La Familia community drug and alcohol prevention program: Family-centered model for working with inner-city Hispanic families.

Substance abuse among Hispanics is on the increase despite national efforts toward reducing it. Researchers and service providers have recognized the specific need for better prevention models that address the issues of poor Hispanics. La Familia is a community-based ATOD prevention program that targets Hispanic families with high-risk youth from 6 to 11 years old, and attempts to reduce identified risk factors while building on culturally relevant protective factors. During the 2 years, the program has enrolled 219 youth and their families utilizing existing community networks and aggressive outreach. The program resulted in a 92% retention rate and over 80% attendance per session. As a result of the program, families became more willing to discuss ATOD issues openly and made positive steps toward empowerment.