Vascularization inside the epidermis of Neotropical anurans (Nobleobatrachia).

Anuran skin is a dynamic organ involved in essential functions that strongly correlate with specific morphological traits. Particularly, gas exchange has been associated with epidermal modifications, such as reduced cell layers and increased vascularization. Here, we describe the epidermal morphology and its association with capillary networks in the dorsal skin of 103 Neotropical anurans (Nobleobatrachia) from different ecomorphs and habitats. Additionally, we examined the lateral and ventral skin for a subset of these species. We report intraepidermal capillaries in (i) dorsal skin of Lepidobatrachus laevis and Lepidobatrachus llanensis (burrowing and semi-aquatic Chacoan species), Hyloscirtus colymba and Hyloscirtus palmeri (arboreal species from humid forests), and Alsodes neuquensis and 15 Telmatobius spp. (aquatic and semi-aquatic species from cold environments); (ii) lateral skin of Boana benitezi and H. colymba (arboreal species from humid forests), and (iii) ventral skin of B. benitezi, H. colymba, Atelognathus patagonicus (aquatic species from cold environments), and four Chacoan species, Chacophrys pierottii, Ceratophrys cranwelli (burrowing/terrestrial species), and Lepidobatrachus asper and L. llanensis (burrowing/semi-aquatic species). Also, verrucae hydrophilicae were observed exclusively in the ventral skin of Leptodactylus fuscus, Leptodactylus laticeps (terrestrial and Chacoan species), and B. benitezi. Regardless of the skin region, the capillaries always penetrate the epidermis from the dermis, while epidermal cell layers are flattened. Our findings support previous hypotheses stating that the environment where species occur influences skin changes related to cutaneous respiration (intraepidermal capillaries in different body regions) and water absorption (intraepidermal capillaries associated with verrucae hydrophilicae within ventral skin). Also, phylogeny might influence the development of these structures, as revealed by the presence of intraepidermal capillaries in almost all analyzed species of Telmatobius. Finally, the co-occurrence of verrucae hydrophilicae in the ventral skin of hylids from humid forests, and leptodactylids from the subhumid Chacoan region suggest an independent origin.

Hind limb muscles influence the architectural properties of long bones in frogs.

The Mechanostat Theory states that osteocytes sense both the intensity and directionality of the strains induced by mechanical usage and modulate the bone design accordingly. In long bones, this process may adapt anterior-posterior and lateral-medial strength to their mechanical environment showing regional specificity. Anuran species are ideal for analyzing the muscle-bone relationships related to the different mechanical stresses induced by their many locomotor modes and habitat uses. This work aimed to explore the relationships between indicators of the force of the most relevant muscles to locomotion and the mechanical properties of femur and tibia fibula in preserved samples of three anuran species with different habitat use (aquatic, arboreal) and locomotion modes (swimmer, jumper, walker/climber). For that purpose, we measured the anatomical cross-sectional area of each dissected muscle and correlated it with the moments of inertia and bone strength indices. Significant, species-specific covariations between muscle and bone parameters were observed. Pseudis platensis, the aquatic swimmer, showed the largest muscles, followed by Boana faber, the jumper and Phyllomedusa sauvagii, the walker/climber. As we expected, bigger muscles correlate with bone parameters in all the species. Nevertheless, smaller muscles also play an important role in bone design. In aquatic species, muscle interaction enhances mostly lateral bending strength throughout the femur and lateral and antero-posterior bending strength in the tibia fibula. In the jumper species, muscles affected the femur and tibia fibula mostly in anterior-posterior bending. In the walker/climber species, responses involving both antero-posterior and lateral bending strengths were observed in the femur and tibia fibula. These results show that bones will be more or less resistant to lateral and antero-posterior bending according to the different mechanical challenges of locomotion in aquatic vs. arboreal habitats. This study provides new evidence of the muscle-bone relationships in three frog species associated with their different locomotion and habitat uses, highlighting the crucial role of muscle in determining the architectural properties of bones.

[Chronotherapy of affective disorders: principles and clinical aspects]. / Chronotherapie affektiver Störungen: Grundlagen und klinische Aspekte.

BACKGROUND: Chronobiological processes play a critical role in the initial manifestation and course of affective disorders. Chronotherapeutic agents aim to improve sleep-wake cycle disturbances and affective symptoms by modulating the chronobiological neuronal circuitry. OBJECTIVE: To review the different chronotherapeutic procedures, the current evidence situation and recommendations for clinical applications. METHOD: Narrative review. RESULTS: Chronotherapeutic interventions for patients with affective disorders can be nonpharmacological, e.g., light therapy, sleep deprivation, sleep phase advance and dark therapy, pharmacological in the form of melatonin and psychological consisting of interpersonal and social rhythm therapy or cognitive behavioral therapy for insomnia modified for patients with bipolar disorder. Nearly all these interventions show promising data regarding their efficacy in acute depressive or manic episodes or as maintenance therapy. For melatonin, there is less evidence for improvement of affective symptoms than for stabilizing the sleep-wake cycle. Some interventions are well-suited for an outpatient setting, e.g., light therapy, dark therapy and psychotherapy, while others, such as triple chronotherapy consisting of sleep deprivation, sleep phase advance and light therapy, are more suited for in-patient treatment. CONCLUSION: Chronotherapeutic interventions are versatile in their application and can be combined with each other and used concomitantly with classical psychopharmacotherapy. With a benign side effect profile and good evidence for efficacy, they could play an important role in the treatment of affective disorders; however, this potential is used too rarely in the clinical context.

Delimiting the boundaries of sesamoid identities under the network theory framework.

Sesamoid identity has long been the focus of debate, and how they are linked to other elements of the skeleton has often been considered relevant to their definition. A driving hypothesis of our work was that sesamoids' nature relies deeply on their connections, and thus we propose an explicit network framework to investigate this subject in Leptodactylus latinasus (Anura: Leptodactylidae). Through the dissection of L. latinasus' skeleton, we modeled its anatomical network where skeletal elements were considered nodes while joints, muscles, tendons, and aponeurosis were considered links. The skeletal elements were categorized into canonical skeletal pieces, embedded sesamoids, and glide sesamoids. We inquired about the general network characterization and we have explored further into sesamoid connectivity behavior. We found that the network is structured in a modular hierarchical organization, with five modules on the first level and two modules on the second one. The modules reflect a functional, rather than a topological proximity clustering of the skeleton. The 25 sesamoid pieces are members of four of the first-level modules. Node parameters (centrality indicators) showed that: (i) sesamoids are, in general terms, peripheral elements of the skeleton, loosely connected to the canonical bone structures; (ii) embedded sesamoids are not significantly distinguishable from canonical skeletal elements; and (iii) glide sesamoids exhibit the lowest centrality values and strongly differ from both canonical skeletal elements and embedded sesamoids. The loose connectivity pattern of sesamoids, especially glides, could be related to their evolvability, which in turn seems to be reflected in their morphological variation and facultative expression. Based on the connectivity differences among skeletal categories found in our study, an open question remains: can embedded and glide sesamoids be defined under the same criteria? This study presents a new approach to the study of sesamoid identity and to the knowledge of their morphological evolution.

Biomechanical properties of anuran long bones: correlations with locomotor modes and habitat use.

Long bones are subjected to mechanical loads during locomotion that will influence their biomechanical properties through a feedback mechanism (the bone mechanostat). This mechanism adapts the spatial distribution of the mineralized tissue to resist compression, bending and torsion. Among vertebrates, anurans represent an excellent group to study long bone properties because they vary widely in locomotor modes and habitat use, which enforce different skeletal loadings. In this study, we hypothesized that (a) the cortical bone mass, density and design of anuran femur and tibiofibula would reflect the mechanical influences of the different locomotor modes and habitat use, and (b) the relationships between the architectural efficiency of cortical design (cross-sectional moments of inertia) and the intrinsic stiffness of cortical tissue [cortical mineral density; the 'distribution/quality' (d/q) relationship] would describe some inter-specific differences in the efficiency of the bone mechanostat to improve bone design under different mechanical loads. To test this hypothesis, we determined tomographic (peripheral quantitative computed tomography) indicators of bone mass, mineralization, and design along the femur and tibiofibula of four anuran species with different modes of locomotion and use of habitat. We found inter-specific differences in all measures between the distal and proximal ends and mid-diaphysis of the bones. In general, terrestrial-hopper species had the highest values. Arboreal-walker species had the lowest values for all variables except for cortical bone mineral density, which was lowest in aquatic-swimmer species. The d/q relationships showed similar responses of bone modeling as a function of cortical stiffness for aquatic and arboreal species, whereas terrestrial-hoppers had higher values for moments of inertia regardless of the tissue compliance to be deformed. These results provide new evidence regarding the significant role of movement and habitat use in addition to the biomechanical properties of long bones within a morpho-functional and comparative context in anuran species.

Sesamoids in tetrapods: the origin of new skeletal morphologies.

Along with supernumerary bones, sesamoids, defined as any organized intratendinous/intraligamentous structure, including those composed of fibrocartilage, adjacent to an articulation or joint, have been frequently considered as enigmatic structures associated with the joints of the skeletal system of vertebrates. This review allows us to propose a dynamic model to account for part of skeletal phenotypic diversity: during evolution, sesamoids can become displaced, attaching to and detaching from the long bone epiphyses and diaphysis. Epiphyses, apophyses and detached sesamoids are able to transform into each other, contributing to the phenotypic variability of the tetrapod skeleton. This dynamic model is a new paradigm to delineate the contribution of sesamoids to skeletal diversity. Herein, we first present a historical approach to the study of sesamoids, discussing the genetic versus epigenetic theories of their genesis and growth. Second, we construct a dynamic model. Third, we present a summary of literature on sesamoids of the main groups of tetrapods, including veterinary and human clinical contributions, which are the best-studied aspects of sesamoids in recent decades. Finally, we discuss the identity of certain structures that have been labelled as sesamoids despite insufficient formal testing of homology. We also propose a new definition to help the identification of sesamoids in general. This review is particularly timely, given the recent increasing interest and research activity into the developmental biology and mechanics of sesamoids. With this updated and integrative discussion, we hope to pave the way to improve the understanding of sesamoid biology and evolution.

Movement and joints: effects of overuse on anuran knee tissues.

Movement plays a main role in the correct development of joint tissues. In tetrapods, changes in normal movements produce alterations of such tissues during the ontogeny and in adult stages. The knee-joint is ideal for observing the influence of movement disorders, due to biomechanical properties of its components, which are involved in load transmission. We analyze the reaction of knee tissues under extreme exercise in juveniles and adults of five species of anurans with different locomotor modes. We use anurans as the case study because they undergo great mechanical stress during locomotion. We predicted that (a) knee tissues subjected to overuse will suffer a structural disorganization process; (b) adults will experience deeper morphological changes than juveniles; and (c) morphological changes will be higher in jumpers compared to walkers. To address these questions, we stimulated specimens on a treadmill belt during 2 months. We performed histological analyses of the knee of both treated and control specimens. As we expected, overuse caused structural changes in knee tissues. These alterations were gradual and higher in adults, and similar between jumpers and walkers species. This study represents a first approach to the understanding of the dynamics of anuran knee tissues during the ontogeny, and in relation to locomotion. Interestingly, the alterations found were similar to those observed in anurans subjected to reduced mobility and also to those described in joint diseases (i.e., osteoarthritis and tendinosis) in mammals, suggesting that among tetrapods, changes in movement generate similar responses in the tissues involved.

On the Presence of the Patella in Frogs.

The patella is one of the most studied sesamoids. Historically, the patella is described as a big sesamoid embedded in the tendon of the quadriceps femoris muscle. This sesamoid is studied from developmental, functional, clinical, and anatomical perspectives. The presence of a patella is reported in squamatans, birds, and mammals. Lissamphibians are identified as the major lineage that fail to develop a patella. However, this sesamoid is reported at least once in anurans, but without detailed anatomical discussions. Through anatomical and histological studies we examined the topography and tissue composition of two structures that we identify as the proximal and distal patellae in several anuran species. We explored the evolution of these sesamoids through ancestral state reconstruction, finding that they are ancestral for amphibians and possibly tetrapods as a whole. The presence of these patellae in anurans would roll back their origin to the last common ancestor of tetrapods. From a functional perspective, the overwhelming evidence of fibrocartilage as a clear response to compression suggests that the fibrocartilaginous patellae could also withstand the mechanical stress generated on the knee undergoing compression during limb extension. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1747-1755, 2017. © 2017 Wiley Periodicals, Inc.

Sulfonylurea Therapy Benefits Neurological and Psychomotor Functions in Patients With Neonatal Diabetes Owing to Potassium Channel Mutations.

OBJECTIVE: Neonatal diabetes secondary to mutations in potassium-channel subunits is a rare disease but constitutes a paradigm for personalized genetics-based medicine, as replacing the historical treatment with insulin injections with oral sulfonylurea (SU) therapy has been proven beneficial. SU receptors are widely expressed in the brain, and we therefore evaluated potential effects of SU on neurodevelopmental parameters, which are known to be unresponsive to insulin. RESEARCH DESIGN AND METHODS: We conducted a prospective single-center study. Nineteen patients (15 boys aged 0.1-18.5 years) were switched from insulin to SU therapy. MRI was performed at baseline. Before and 6 or 12 months after the switch, patients underwent quantitative neurological and developmental assessments and electrophysiological nerve and muscle testing. RESULTS: At baseline, hypotonia, deficiencies in gesture conception or realization, and attention disorders were common. SU improved HbA1c levels (median change -1.55% [range -3.8 to 0.1]; P < 0.0001), intelligence scores, hypotonia (in 12 of 15 patients), visual attention deficits (in 10 of 13 patients), gross and fine motor skills (in all patients younger than 4 years old), and gesture conception and realization (in 5 of 8 older patients). Electrophysiological muscle and nerve tests were normal. Cerebral MRI at baseline showed lesions in 12 patients, suggesting that the impairments were central in origin. CONCLUSIONS: SU therapy in neonatal diabetes secondary to mutations in potassium-channel subunits produces measurable improvements in neuropsychomotor impairments, which are greater in younger patients. An early genetic diagnosis should always be made, allowing for a rapid switch to SU.

Further Data on Sesamoid Identity from Two Anuran Species.

Considering that the identification of equivalent entities is the basis for any comparative analysis, we compare the histology, histochemistry, shape and dimensions of epiphyses, carpal and sesamoids in two anuran frogs. Our goal was to explore the morphological correspondence among these three skeletal elements in order to clarify the sesamoid identity. We studied the skeletogenesis, contour geometric morphometry and dimensions of forelimb elements of juveniles of two anurans species Leptodactylus bufonius and Rhinella arenarum. Skeletogenesis in anurans present a common trait between carpals and sesamoids: both elements exhibit endochondral ossification. A difference between these elements is the presence of fibrocartilage in the development of sesamoids. The geometric morphometry does not allow us to establish a shape pattern that can be compared either between sesamoids and epiphyses or carpals. With regard to dimensions, our data indicate that bones categorization based on these aspects is ambiguous and therefore is useless to classify of skeletal bones. The data about tissue differentiation of sesamoids provide evidence that support the idea that these elements should be considered part of the typical endowment of the vertebrate skeleton.

Carrageenan plasma expander: effect on mesenteric ischemia-reperfusion injury in the rat.

The effect of carrageenan against ischemia-reperfusion injury was investigated. Rats were grouped into four, subjected to 10 min of ischemia and reperfusion in their mesenteric venules and 30% of their blood volume was replaced with either normal saline solution, dextran 70 in 5% dextrose, or iota-carrageenan solution, while the fourth group remained untreated. Parameters such as venule diameter, red blood cell velocity, leukocyte rolling and adhesion, were then observed by video. Findings reveal that carrageenan infusion has the tendency to attenuate leukocyte rolling and adhesion, increase venule diameter and regain erythrocyte velocity after ischemia. The data suggest that the effects of carrageenan were comparable to that of either of the more commercially used plasma expanders, dextran 70 or normal saline solution. Overall, however, these did not differ significantly from the untreated rats.