Retractor Muscle Research Articles

Macro- and microscopic morphology of the reproductive system of the terrestrial snail Macrochlamys indica (Godwin-Austen, 1883) (Eupulmonata, Stylommatophora, Ariophantidae)

ABSTRACT The morpho-anatomical and morphometrical characteristics of the reproductive system, together with the spermatophore and dart apparatus, of Macrochlamys indica are described and the results compared with available data of other Macrochlamys species. Histology of some reproductive structures such as the ovotestis, hermaphrodite duct, albumen gland, penis and dart shaft of M. indica are also studied. A muscular, brownish capsule is developed between the free oviduct and the vagina, here named as vaginoviducal capsule and its location is species-specific. The distal end of the vaginoviducal capsule bifurcates into a free oviduct and the duct of the gametolytic organ. The gametolytic sac of the gametolytic organ is a whitish, tubular structure that becomes pinkish and club-shaped in inseminated snails. Two to seven spermatophores are found in the pinkish gametolytic sac. The spermatophore is a whip-like, translucent structure. The epiphallus possesses a coiled epiphallic caecum to which a penial retractor muscle is attached. The penis is a short, muscular structure with a distinct penial caecum. The dart apparatus is well-developed, having four distinct parts. The proximal part of the dart apparatus possesses a non-disposable muscular dart. The dart shaft includes a central core which is encircled by many layers of circular muscle cells.

The neuromuscular system of the sheep tapeworm Moniezia expansa.

Cestodes are common gastrointestinal parasites of humans and livestock. They attach to the host gut and, without a mouth or intestinal system, absorb nutrients through their epidermis. Here we show that despite this simplified anatomy and sessile lifestyle, they maintain a complex neuromuscular system. We used fluorescently labelled phalloidin as a specific probe for filamentous actin to define the overall organisation of several distinct muscle systems in the cyclophyllidean Moniezia expansa. Like all flatworms, the body wall musculature below the neodermis of this intestinal parasite of sheep is characterised by outer circular and inner longitudinal muscle fibres. Diagonal fibres, typically found in free-living and trematode platyhelminths, on the other hand, are notably absent. Prominent longitudinal sheaths dominate the parenchyma and provide retractor muscles to the four acetabula in the scolex; they attach at the bottom of each cup-shaped holdfast. Within sexually mature proglottids, circular fibres dominate the duct walls of the male and female reproductive systems. Nerve cells and fibres that express serotonin or neuropeptide F supply well-developed innervation to several of the described muscle systems: emanating from the central nervous system, fibres in the periphery develop pervasive nerve nets that anastomose within body wall musculature as well as the parenchymal longitudinal and oblique muscle fibres, and innervate the sexual organs and gonopore in mature proglottids. Using homology searches, we provide evidence for 20 neuropeptide precursors together with four prepropeptide processing enzymes as well as several 5-HT signalling components to be represented in the Moniezia transcriptome.

Ecomorphology of the pectoral girdle in anurans (Amphibia, Anura): Shape diversity and biomechanical considerations.

Frogs and toads (Lissamphibia: Anura) show a diversity of locomotor modes that allow them to inhabit a wide range of habitats. The different locomotor modes are likely to be linked to anatomical specializations of the skeleton within the typical frog Bauplan. While such anatomical adaptations of the hind limbs and the pelvic girdle are comparably well understood, the pectoral girdle received much less attention in the past. We tested for locomotor‐mode‐related shape differences in the pectoral girdle bones of 64 anuran species by means of micro‐computed‐tomography‐based geometric morphometrics. The pectoral girdles of selected species were analyzed with regard to the effects of shape differences on muscle moment arms across the shoulder joint and stress dissipation within the coracoid. Phylogenetic relationships, size, and locomotor behavior have an effect on the shape of the pectoral girdle in anurans, but there are differences in the relative impact of these factors between the bones of this skeletal unit. Remarkable shape diversity has been observed within locomotor groups indicating many‐to‐one mapping of form onto function. Significant shape differences have mainly been related to the overall pectoral girdle geometry and the shape of the coracoid. Most prominent shape differences have been found between burrowing and nonburrowing species with headfirst and backward burrowing species significantly differing from one another and from the other locomotor groups. The pectoral girdle shapes of burrowing species have generally larger moment arms for (simulated) humerus retractor muscles across the shoulder joint, which might be an adaptation to the burrowing behavior. The mechanisms of how the moment arms were enlarged differed between species and were associated with differences in the reaction of the coracoid to simulated loading by physiologically relevant forces.

The pros and cons of additional axillary arm for transoral robotic thyroidectomy.

BackgroundTransoral vestibular approach thyroidectomy using robotic system has advantages with articulating instrumentation. Transoral robotic thyroidectomy (TORT) can be done either using just two robot arms for instruments and an extra one for the endoscopic camera, or using three robot arms for instruments (third arm through axila) and an additional arm for the camera.Pros of additional axillary arm for TORTThe 4th arm through an additional axillary port is mainly responsible for a counter-traction of strap muscles and thyroid tissue. The additional axillary port tract is also an excellent passage for the specimen removal with lower risk of disruption or fragmentation. Ultimately, these merits from the additional axillary arm allows TORT to be performed safely in a wide range of patient groups.Cons of additional axillary arm for TORTOne of the issue with the additional axillary arm in TORT is that it leaves a cutaneous scar. Another issue to consider is the cost. In some places, robotic surgery operation fee varies with the number of arms used during the operation. Retraction of strap muscles through subcutaneous stitches applied after establishing the working space may make up for the lack of counter-traction.ConclusionTORT can be done safely with or without the transaxillary arm and surgeon may consider pros and cons based on multiple factors.

Obesity and ventral hernia in the context of drug addiction and mental instability: a complex scenario successfully treated with preoperative progressive pneumoperitoneum

Abstract Surgery in loss of domain hernia can result in high morbidity and mortality. Chronic muscle retraction along with the reduced volume of the peritoneal cavity can lead to potential problems such as abdominal compartment syndrome, ventilatory restriction and an elevated risk of hernia recurrence. This is affected even further by obesity; a high body mass index is strongly associated with poor outcomes after ventral hernia repair. In these individuals, preoperative preparation is vital as it can reduce surgical risks and improve patients’ outcomes. There are many strategies available. Nonetheless, an individualized case approach by a multidisciplinary team is crucial to accurately treat this troublesome pathology. We present the case of a 41-year-old obese patient with a loss of domain ventral hernia. As he had a drug addiction and several psychologic difficulties, a tailored approach was needed to successfully treat the hernia. After preoperative preparation and surgery, the patient underwent full recovery.

Intraoperative identification of mixed activation profiles during hypoglossal nerve stimulation.

The effectiveness of hypoglossal nerve stimulation (HGNS) in the treatment of obstructive sleep apnea (OSA) depends on the selective stimulation of nerve fibers that innervate the tongue muscles that produce tongue protrusion (genioglossus) and stiffening (transverse/vertical) while avoiding fibers that innervate muscles that produce tongue retraction (styloglossus/hyoglossus). Postoperative treatment failures can be related to mixed activation of retractor and protrusor muscles, despite intraoperative efforts to identify and avoid nerve fibers that innervate the retractor muscles. This study describes a novel intraoperative protocol that more optimally identifies mixed activation by utilizing an expanded set of stimulation/recording parameters. This study was a case series in a university hospital setting of patients undergoing unilateral hypoglossal nerve stimulation implantation for obstructive sleep apnea. Data included electromyographic responses in the genioglossus and styloglossus/hyoglossus to intraoperative stimulation with an implantable pulse generator using unipolar (- - -, o-o) and bipolar (+-+) settings. In a subset of patients (3/55), low-intensity unipolar implantable pulse generator stimulation revealed significant mixed activation of the styloglossus/hyoglossus and genioglossus muscles that was not evident under standard bipolar implantable pulse generator stimulation conditions. Additional surgical dissection and repositioning of the electrode stimulation cuff reduced mixed activation. A novel intraoperative neurophysiological monitoring protocol was able to detect significant mixed activation during hypoglossal nerve stimulation that was otherwise absent using standard parameters. This enabled successful electrode cuff repositioning and a dramatic reduction of mixed activation.

A Small Amount of Retraction Force Results in Inadvertent Piriformis Muscle Damage During a Piriformis-Sparing Approach to the Hip.

Piriformis-sparing approaches to the hip allow surgeons to avoid releasing the piriformis tendon during total hip arthroplasty; however, the consequences of retracting an intact piriformis tendon during such an approach remain ill-defined. The present study aimed to determine the upper limit of force that can be applied during retraction of the piriformis tendon to expose the hip, and to quantify the resultant damage to the piriformis musculotendinous complex. A patent-pending instrumented retractor was designed to record the applied force, duration, and angle of retraction during a piriformis-sparing posterior approach to the hip. In addition to the data collected with use of the instrumented retractor, damage to the piriformis muscle and tendon was quantified by a blinded observer. There was no damage to the piriformis tendon in 22 (96%) of 23 hips during piriformis retraction for visualization of the hip capsule; however, there was complete or partial damage to the piriformis muscle at the sacral origin, belly, or musculotendinous junction (i.e., outside the surgical field) noted in 21 (91%) of 23 hips. The mean peak force to failure of the piriformis muscle was exceedingly small (29.0 ± 9.4 N; range, 10.1 to 44.9 N). The mean peak force applied to the piriformis retractor is much less than the force required for several common daily activities, such as opening a door or crushing an empty aluminum can. Soft-tissue damage that occurs outside the surgical field during the retraction of unreleased muscles, like the piriformis muscle, is common and remains an uncontrolled surgical variable. This inadvertent soft-tissue damage is not routinely accounted for when accessing the invasiveness of a procedure. Hence, it is no longer adequate to define a minimally invasive surgical procedure simply as an approach that involves the limited release of anatomical structures. The use of instrumented retractors may redefine surgical invasiveness by providing data that could alter our understanding of the soft-tissue damage caused by retraction and open the possibility of robot-assisted or damage-limiting retractor systems.

Endoscopic submucosal dissection of large pedunculated polyps with wide stalks: a retrospective multicenter study.

Endoscopic resection of large pedunculated colorectal polyps is technically difficult, especially when the polyp is large and has such a thick stalk that it is either too difficult or impossible to resect prophylactically by a conventional snare. Here, we evaluated the feasibility of ESD for large pedunculated polyps with wide stalks. 29 patients with large pedunculated polyps that were not resectable by polypectomy or endoscopic mucosal resection were enrolled in the study. En bloc resection was achieved in 28/29 polyps. One suspended case was due to severe fibrosis with muscle retraction signs. The mean diameter of the 29 polyp heads was 39.7 (standard deviation 6.9) mm. Submucosal fibrosis was present in 16 polyps (9 mild; 7 severe). The stalks of severely fibrotic polyps were significantly thicker than those of polyps with no or mild fibrosis. The curative resection rate was 85.7 % without severe complications. ESD is feasible for the removal of large pedunculated polyps with wide stalks when conventional snare resection is difficult or impossible.

New freshwater mussels (Bivalvia, Unionida) with potential trigonioidid and hyriid affinities from the Early Cretaceous of Brazil

Two new taxa of freshwater mussels (Bivalvia: Unionida) from the Aptian Crato Formation of the Araripe Basin, NE Brazil, are described. The fossil bivalves are confined to 30- to 130-cm-thick bioturbated mudstones overlying the fossil-rich laminated limestones of the Crato Formation Konservat-Lagerstätte. Individuals are often preserved with closed or splayed articulated valves, some of them potentially in life position, forming an autochthonous to parautochthonous assemblage. Monginellopsis bellaradiata nov. gen., nov. sp. shares key characters with the Trigonioidoidea: (i) the anterior pedal retractor muscle scar is clearly separated from the anterior adductor muscle scar; (ii) the shell has fold-like radial ribs on the posterior half; (iii) a right valve anterior tooth has a striated facet. Araripenaia elliptica nov. gen., nov. sp. is the most abundant and widely distributed unionid of the Crato Formation. Its ornament of anterior inverted V-shaped riblets, and central and posterior radial and sub-radial riblets resembles modern and fossil Hyriidae from the Americas, but also Trigonioidoidea from Eurasia. Its dentition of two smooth anterior pseudocardinals and two smooth posterior laterals in each valve provides no further clues for systematic assignment; muscle scars are not preserved. Assignment to the Hyriidae would make Araripenaia the oldest member of this family known from South America. Moreover, this bivalve assemblage of trigonioidoidids, hyriids, and previously reported silesunionoids suggests palaeobiogeographic links to other areas in both Gondwana and Laurasia.

ON IMPROVING TREATMENT OF SUPRACONDYLAR AND CONDYLAR HUMERAL FRACTURES IN CHILDREN

The article presents the analyses of the treatment outcomes of 155 children with supracondylar (45 cases, 29%) and condylar (110 cases, 71%) humeral fractures. The age of patients ranged from 1 to 15 years; boys 107 (69%) got traumas twice as much as girls 48 (31%); the traumas of left upper extremities were more commonly registered and made up 100 cases (64,5%). All patients were examined clinically and radiologically. Domestic injuries resulted in supracondylar and condylar femoral fractures were the most commonly registered in 8-10 year old children. Most patients (63.2%) demonstrated good treatment outcomes, 42 (27.1%) patients demonstrated satisfactory outcomes, and in 15 cases (9.7%) the outcomes were unsatisfactory. Analysis of the treatment outcomes showed that stable fixation ensured good functional results and did not cause secondary joint deformation. Long-term results were studied in 136 operated patients, 94 cases (60.6 ± 3.92%) were defined as excellent, 31 cases (20.0 ± 3.21%) were found as satisfactory, 11 (7.1 ± 2, 06%) cases were unsatisfactory due to the damage to the growth zone. Following the conservative treatment of 19 patients, the articulation in the joint was restored in 7.1%; in 4 (2.6 ± 1.27%) patients the results were defined as good, in 11 (7.1 ± 2.06%) as satisfactory, and in 4 (2.6 ± 2.7%) as unsatisfactory. The decreased oedema and muscle retraction during the development of secondary displacement of fragments, closed one-step reposition and osteosynthesis with Kirchner needles was performed in 2.6% of patients. Thus, the proposed working scheme for the treatment of supracondylar and condylar femoral fractures enables to determine differentiated treatment tactics in the children depending on their age and the type of the fracture. Stable fixation ensures achieving of good functional treatment outcomes and prevents the development of the secondary joint deformation.

Image-guided botulinum toxin injection in the lateral abdominal wall prior to abdominal wall reconstruction surgery: review of techniques and results.

Ventral hernias represent the most common complication after abdominal surgery. Loss of domain and/or large ventral hernias in patients are especially challenging for surgeons to manage, but preoperative image-guided botulinum toxin injection has emerged as an effective adjunct to abdominal wall surgery. Loss of domain is caused by chronic muscle retraction of the lateral abdominal wall and leads to an irreducible protrusion of abdominal viscera into the hernia sac. Botulinum toxin can be used in the oblique muscles as a chemical component relaxation technique to aid abdominal wall reconstruction. Intramuscular botulinum toxin injection causes functional denervation by blocking neurotransmitter acetylcholine release resulting in flaccid paralysis and elongation of lateral abdominal wall muscles, increasing the rate of fascial closure during abdominal wall reconstruction, and decreasing recurrence rates. In total, 200-300units of onabotulinumtoxinA (Botox®) or 500units of abobotulinumtoxinA (Dypsort®) in a 2:1 dilution with normal saline is most commonly used. Botulinum toxin can be injected with ultrasonographic, EMG, or CT guidance. Injection should be performed at least 2weeks prior to abdominal wall reconstruction, for maximal effect during surgery. At minimum, botulinum toxin should be injected into the external and internal oblique muscles at three separate sites bilaterally for a total of six injections. Although botulinum toxin use for abdominal wall reconstruction is currently not indicated by the Food and Drug Administration, it is safe with only minor complications reported in literature.

PREOPERATIVE PROGRESSIVE PNEUMOPERITONEUM FOR INCISIONAL HERNIA REPAIR WITH LOSS OF DOMAIN: CASE REPORT.

Incisional hernias with loss domain (HIPD), has a prevalence between 5 - 20%, due to its technical complexity are a challenge for abdominal wall surgeon, because decrease in abdominal compliance, for muscle atrophy and retraction, as well as complications associated with the procedure. We present the preoperative use of progressive pneumoperitoneum (NPP), as a technique for preparing the abdominal wall, by placing a multipurpose permanent catheter (pig tail type) guided by computed tomography, for a 69-year-old male patient, farmer, and colostomy carrier. by sigma volvulus, which presented abdominal sepsis secondary to anastomosis dehiscence, which led to a colostomy, and HIPD formation of 25 x 15 cm. The benefits of NPP are: it reduces the size of the second cavity formed, facilitates the placement of the mesh, reduces the tension in the closure of the abdominal wall and the development of intra-abdominal hypertension syndrome, therefore a lower probability of post-surgical recurrence. The repair technique used was release of the transverse muscle of the abdomen (TAR), which is indicated in HIPD. CONCLUSIONS. HIPD repair is technically difficult because compliance of the abdominal wall is affected, even more so in our case due to the presence of a colostomy. Optimization of the preoperative abdominal wall with the progressive pneumoperitoneum technique plus the TAR technique is one of the valid options available to achieve this goal.

Avaliação de rufiões bubalinos submetidos à técnica cirúrgica de fixação da curvatura caudal da flexura sigmóide com miectomia do músculo retrator do pênis

The objective of this work was to evaluate the efficiency technique of fixation of the caudal curvature of the sigmoid flexure with myectomy of the penis retractor muscle and the performance of teaser bulls after surgery, through the detection of females in estrus, without performing the copulation. 12 teaser buffaloes were used without defined breed, with an average age of 20 months, weighing on average 200 kg. The animals were subjected to food and water fasting for 12 hours to provide tranquilization in advance. The surgical procedure consisted of the exteriorization of the sigmoid flexure, myectomy of penis retractor muscle and fixation of the caudal curvature of the penis sigmoid flexure. Of the 12 evaluated teaser buffaloes in the libido test, 100% performed the flehmen reflex, mount attempt, incomplete and complete jump with total inability of the penis exposure. It was concluded that this technique can be used safely, having simplicity in its execution, effective results and mainly low cost, not interfering in the animals’ libido. The animals when tested as teaser buffaloes kept the libido during the experimental period with total inability of exposure of the penis.

Molecular approaches underlying the oogenic cycle of the scleractinian coral, Acropora tenuis

This study aimed to elucidate the physiological processes of oogenesis in Acropora tenuis. Genes/proteins related to oogenesis were investigated: Vasa, a germ cell marker, vitellogenin (VG), a major yolk protein precursor, and its receptor (LDLR). Coral branches were collected monthly from coral reefs around Sesoko Island (Okinawa, Japan) for histological observation by in situ hybridisation (ISH) of the Vasa (AtVasa) and Low Density Lipoprotein Receptor (AtLDLR) genes and immunohistochemistry (IHC) of AtVasa and AtVG. AtVasa immunoreactivity was detected in germline cells and ooplasm, whereas AtVG immunoreactivity was detected in ooplasm and putative ovarian tissues. AtVasa was localised in germline cells located in the retractor muscles of the mesentery, whereas AtLDLR was localised in the putative ovarian and mesentery tissues. AtLDLR was detected in coral tissues during the vitellogenic phase, whereas AtVG immunoreactivity was found in primary oocytes. Germline cells expressing AtVasa are present throughout the year. In conclusion, Vasa has physiological and molecular roles throughout the oogenic cycle, as it determines gonadal germline cells and ensures normal oocyte development, whereas the roles of VG and LDLR are limited to the vitellogenic stages because they act in coordination with lipoprotein transport, vitellogenin synthesis, and yolk incorporation into oocytes.

The Tail of the Late Jurassic Sauropod Giraffatitan brancai: Digital Reconstruction of Its Epaxial and Hypaxial Musculature, and Implications for Tail Biomechanics

Dinosaur locomotion and biomechanics, especially of their pelvic girdles and hind limbs, have been analysed in numerous studies. However, detailed volumetric musculoskeletal models of their tails are rarely developed. Here, we present the first detailed three-dimensional volumetric reconstruction of the caudal epaxial and hypaxial musculature of the Late Jurassic sauropod Giraffatitan brancai, and highlight the importance and necessity of 3D modelling in musculoskeletal reconstructions. The tail of this basal macronarian is relatively short compared to diplodocids and other coexisting macronarians. The centre of mass lies well in front of the hind limbs, which support only ca. half the body weight. Still, our reconstruction suggests a total weight for the entire tail of ca. 2500 kg. We conclude that the hypaxial and hind limb muscles (more specifically the M. caudofemoralis longus and its counterpart the M. ilioischiocaudalis) in Giraffatitan were well developed and robustly built, compensating for the shorter length of the M. caufodemoralis longus, the main hind limb retractor muscle, in comparison with other sauropods. Our methodology allows a better-constrained reconstruction of muscle volumes and masses, in extinct taxa, and thus force and weight distributions, throughout the tail, than non-volumetric approaches.

Rapid Adaptation to Changing Mechanical Load by Ordered Recruitment of Identified Motor Neurons.

As they interact with their environment and encounter challenges, animals adjust their behavior on a moment-to-moment basis to maintain task fitness. This dynamic process of adaptive motor control occurs in the nervous system, but an understanding of the biomechanics of the body is essential to properly interpret the behavioral outcomes. To study how animals respond to changing task conditions, we used a model system in which the functional roles of identified neurons and the relevant biomechanics are well understood and can be studied in intact behaving animals: feeding in the marine mollusc Aplysia. We monitored the motor neuronal output of the feeding circuitry as intact animals fed on uniform food stimuli under unloaded and loaded conditions, and we measured the force of retraction during loaded swallows. We observed a previously undescribed pattern of force generation, which can be explained within the appropriate biomechanical context by the activity of just a few key, identified motor neurons. We show that, when encountering load, animals recruit identified retractor muscle motor neurons for longer and at higher frequency to increase retraction force duration. Our results identify a mode by which animals robustly adjust behavior to their environment, which is experimentally tractable to further mechanistic investigation.

Biportal endoscopic spinal surgery for lumbar spinal stenosis

Lumbar spinal stenosis is a common disease in the elderly (over 60 years old). Common surgical options for treating lumbar stenosis include open decompression laminectomy, foraminotomy, and spinal fusion. Currently, the gold standard for treating lumbar stenosis that is resistant to conservative treatment is laminectomy with facet preservation.The purpose is to conduct a comparative assessment of the results of studies of the effectiveness and advantages of unilateral biportal endoscopy (UBE) in comparison with other methods of decompression of lumbar spinal stenosis based on the literature data.Results. A meta-analysis of the studies showed that the advantage of UBE is the possibility of preventing atrophy of the paraspinal muscles due to a decrease in muscle dissection and retraction compared to open decompression. This technique allows reducing the trauma of the nerve structures since it is possible to carry out manipulations finely and accurately due to significantly enlarged images. Also, due to the wide viewing angle through the endoscope, decompression of the contralateral side is relatively simple.Conclusions. The UBE technique has several advantages compared to other minimally invasive methods, namely, reduction of damage to the posterior ligamentous apparatus and soft tissues, complete decompression of damaged structures and lower risk of infection.

Key novelties in the evolution of the aquatic colonial phylum Bryozoa: evidence from soft body morphology.

ABSTRACTMolecular techniques are currently the leading tools for reconstructing phylogenetic relationships, but our understanding of ancestral, plesiomorphic and apomorphic characters requires the study of the morphology of extant forms for testing these phylogenies and for reconstructing character evolution. This review highlights the potential of soft body morphology for inferring the evolution and phylogeny of the lophotrochozoan phylum Bryozoa. This colonial taxon comprises aquatic coelomate filter‐feeders that dominate many benthic communities, both marine and freshwater. Despite having a similar bauplan, bryozoans are morphologically highly diverse and are represented by three major taxa: Phylactolaemata, Stenolaemata and Gymnolaemata. Recent molecular studies resulted in a comprehensive phylogenetic tree with the Phylactolaemata sister to the remaining two taxa, and Stenolaemata (Cyclostomata) sister to Gymnolaemata. We plotted data of soft tissue morphology onto this phylogeny in order to gain further insights into the origin of morphological novelties and character evolution in the phylum. All three larger clades have morphological apomorphies assignable to the latest molecular phylogeny. Stenolaemata (Cyclostomata) and Gymnolaemata were united as monophyletic Myolaemata because of the apomorphic myoepithelial and triradiate pharynx. One of the main evolutionary changes in bryozoans is a change from a body wall with two well‐developed muscular layers and numerous retractor muscles in Phylactolaemata to a body wall with few specialized muscles and few retractors in the remaining bryozoans. Such a shift probably pre‐dated a body wall calcification that evolved independently at least twice in Bryozoa and resulted in the evolution of various hydrostatic mechanisms for polypide protrusion. In Cyclostomata, body wall calcification was accompanied by a unique detachment of the peritoneum from the epidermis to form the hydrostatic membraneous sac. The digestive tract of the Myolaemata differs from the phylactolaemate condition by a distinct ciliated pylorus not present in phylactolaemates. All bryozoans have a mesodermal funiculus, which is duplicated in Gymnolaemata. A colonial system of integration (CSI) of additional, sometimes branching, funicular cords connecting neighbouring zooids via pores with pore‐cell complexes evolved at least twice in Gymnolaemata. The nervous system in all bryozoans is subepithelial and concentrated at the lophophoral base and the tentacles. Tentacular nerves emerge intertentacularly in Phylactolaemata whereas they partially emanate directly from the cerebral ganglion or the circum‐oral nerve ring in myolaemates. Overall, morphological evidence shows that ancestral forms were small, colonial coelomates with a muscular body wall and a U‐shaped gut with ciliary tentacle crown, and were capable of asexual budding. Coloniality resulted in many novelties including the origin of zooidal polymorphism, an apomorphic landmark trait of the Myolaemata.

Developmental Dynamics of the Larval Muscle System of Bay Scallop (Argopecten irradians)

Though the larval development of bivalves has been extensively studied for commercial purposes, the dynamic development of larval muscle system remains largely unknown. In this study, we characterized the larval muscle system at different developmental stages (D-shaped veligers, umbo veligers and spats) in the bay scallop ( Argopecten irradians ) by phalloidin staining and under a confocal microscopy. The functional muscles are initially established at the early stage of veligers, which have four pairs of velar retractors and one anterior adductor. At the veliger stage, the velum and posterior retractor muscles are functionally important for velar contractility but undergo an irreversible shrink until they disappear at the end of the larval stage. During metamorphosis, three crucial modifications take place in the larval muscle system. The metamorphosis process involves the gradual degeneration of velum retractors, mantle margin development from an unfolded to a three-fold state, and remodeling of the adductor muscle system from dimyarian (two adductors) to monomyarian condition (one adductor) as in juveniles/adults. All retractor muscles are composed of striated muscle, but both anterior and posterior adductors have smooth and striated components. These findings highlight that the morphological changes at different stages are typical features of myogenesis in scallops. The present knowledge on the developmental dynamics of myogenesis in the bay scallop will not only improve our understanding of phenotypic diversity of larval myoanatomy in bivalves, but also provide useful information on the larval culture in hatcheries.

Clinical study of Dysfunctional Ventilatory Weaning Response in critically ill patients.

Objective:to clinically validate the nursing diagnosis of Dysfunctional Ventilatory Weaning Response in adult patients admitted to Intensive Care Units.Method:a concurrent cohort performed with 93 patients admitted to Intensive Care Units. The incidence and incidence density of the diagnosis were estimated, its related factors were identified based on bivariate analysis and clinical indicators for determining its occurrence, according to the global and temporal presentation.Results:the overall incidence of the diagnosis was 44.09% and the incidence density was 14.49 occurrences for every 100 extubations/day. The factors related to the diagnosis were the following: age, clinical severity, fluid balance, oliguria, hemodialysis, edema in upper/lower limbs, anasarca, number of antibiotics, hypothermia, hyperthermia, amount of secretion, muscle retraction, anxiety score, heart rate, use of vasopressors and non-invasive ventilation after extubation. The clinical indicators most frequently identified for determining the diagnosis were the following: tachypnea, drop of saturation and tachycardia. Temporal progression in the severity of these manifestations was found.Conclusion:the Dysfunctional Ventilatory Weaning Response is a common finding in critically ill patients. Some components of the diagnosis of the NANDA-International (2018) version could be clinically validated. It is noteworthy that there are variables not yet described in the taxonomy, demonstrating the need to review this nursing diagnosis.