Evolution of hindlimb muscle anatomy across the tetrapod water-to-land transition, including comparisons with forelimb anatomy

Tetrapod limbs are a key innovation implicated in the evolutionary success of the clade. Although musculoskeletal evolution of the pectoral appendage across the fins‐to‐limbs transition is fairly well documented, that of the pelvic appendage is much less so. The skeletal elements of the pelvic appendage in some tetrapodomorph fish and the earliest tetrapods are relatively smaller and/or qualitatively less similar to those of crown tetrapods than those of the pectoral appendage. However, comparative and developmental works have suggested that the musculature of the tetrapod forelimb and hindlimb was initially very similar, constituting a “similarity bottleneck” at the fins‐to‐limbs transition. Here we used extant phylogenetic bracketing and phylogenetic character optimization to reconstruct pelvic appendicular muscle anatomy in several key taxa spanning the fins‐to‐limbs and water‐to‐land transitions. Our results support the hypothesis that transformation of the pelvic appendages from fin‐like to limb‐like lagged behind that of the pectoral appendages. Compared to similar reconstructions of the pectoral appendages, the pelvic appendages of the earliest tetrapods had fewer muscles, particularly in the distal limb (shank). In addition, our results suggest that the first tetrapods had a greater number of muscle‐muscle topological correspondences between the pectoral and pelvic appendages than tetrapodomorph fish had. However, ancestral crown‐group tetrapods appear to have had an even greater number of similar muscles (both in terms of number and as a percentage of the total number of muscles), indicating that the main topological similarity bottleneck between the paired appendages may have occurred at the origin of the tetrapod crown group

Macro-level Modeling of the Response of C. elegans Reproduction to Chronic Heat Stress

A major goal of systems biology is to understand how organism-level behavior arises from a myriad of molecular interactions. Often this involves complex sets of rules describing interactions among a large number of components. As an alternative, we have developed a simple, macro-level model to describe how chronic temperature stress affects reproduction in C. elegans. Our approach uses fundamental engineering principles, together with a limited set of experimentally derived facts, and provides quantitatively accurate predictions of performance under a range of physiologically relevant conditions. We generated detailed time-resolved experimental data to evaluate the ability of our model to describe the dynamics of C. elegans reproduction. We find considerable heterogeneity in responses of individual animals to heat stress, which can be understood as modulation of a few processes and may represent a strategy for coping with the ever-changing environment. Our experimental results and model provide quantitative insight into the breakdown of a robust biological system under stress and suggest, surprisingly, that the behavior of complex biological systems may be determined by a small number of key components

Calpains Mediate Integrin Attachment Complex Maintenance of Adult Muscle in Caenorhabditis elegans

Two components of integrin containing attachment complexes, UNC-97/PINCH and UNC-112/MIG-2/Kindlin-2, were recently identified as negative regulators of muscle protein degradation and as having decreased mRNA levels in response to spaceflight. Integrin complexes transmit force between the inside and outside of muscle cells and signal changes in muscle size in response to force and, perhaps, disuse. We therefore investigated the effects of acute decreases in expression of the genes encoding these multi-protein complexes. We find that in fully developed adult Caenorhabditis elegans muscle, RNAi against genes encoding core, and peripheral, members of these complexes induces protein degradation, myofibrillar and mitochondrial dystrophies, and a movement defect. Genetic disruption of Z-line– or M-line–specific complex members is sufficient to induce these defects. We confirmed that defects occur in temperature-sensitive mutants for two of the genes: unc-52, which encodes the extra-cellular ligand Perlecan, and unc-112, which encodes the intracellular component Kindlin-2. These results demonstrate that integrin containing attachment complexes, as a whole, are required for proper maintenance of adult muscle. These defects, and collapse of arrayed attachment complexes into ball like structures, are blocked when DIM-1 levels are reduced. Degradation is also blocked by RNAi or drugs targeting calpains, implying that disruption of integrin containing complexes results in calpain activation. In wild-type animals, either during development or in adults, RNAi against calpain genes results in integrin muscle attachment disruptions and consequent sub-cellular defects. These results demonstrate that calpains are required for proper assembly and maintenance of integrin attachment complexes. Taken together our data provide in vivo evidence that a calpain-based molecular repair mechanism exists for dealing with attachment complex disruption in adult muscle. Since C. elegans lacks satellite cells, this mechanism is intrinsic to the muscles and raises the question if such a mechanism also exists in higher metazoans

The expert consensus guideline series: Adherence problems in patients with serious and persistent mental illness

Objectives. Poor adherence to medication treatment can have devastating consequences for patients with mental illness. The goal of this project was to develop recommendations for addressing adherence problems to improve patient outcomes. Methods. The editors identified important topics and questions concerning medication adherence problems in serious mental illness that are not fully addressed in the literature. A survey was developed containing 39 questions (521 options) asking about defining nonadherence, extent of adherence problems in schizophrenia and bipolar disorder, risk factors for nonadherence, assessment methods, and interventions for specific types of adherence problems. The survey was completed by 41(85%) of the 48 experts to whom it was sent. Results of the literature review and survey were used to develop recommendations for assessing and improving adherence in patients with serious mental illness. Results. ASSESSING ADHERENCE: The experts endorsed percentage of medication not taken as the preferred method of defining adherence, with 80% or more of medication taken endorsed as an appropriate cut-off for adherence in bipolar disorder and schizophrenia. Although self- and physician report are the most common methods used to assess adherence in clinical settings, they are often inaccurate and may underestimate nonadherence. The experts recommend that, if possible, clinicians also use more objective measures (e.g., pill counts, pharmacy records, and, when appropriate, serum levels such as are used for lithium). Use of a validated self-report scale may help improve accuracy. SCOPE OF THE PROBLEM: The majority of the experts believed the average patient with schizophrenia or bipolar disorder in their practices takes only 51%-70% of prescribed medication. FACTORS ASSOCIATED WITH NONADHERENCE: The experts endorsed poor insight and lack of illness awareness, distress associated with specific side effects or a general fear of side effects, inadequate efficacy with persistent symptoms, and believing medications are no longer needed as the most important factors leading to adherence problems in schizophrenia and bipolar disorder. The experts considered weight gain a side effect that is very likely to lead to adherence problems in patients with schizophrenia and bipolar disorder; sedation was considered a more important contributor to adherence problems in bipolar disorder than schizophrenia. The experts rated persistent positive or negative symptoms in schizophrenia and persistent grandiosity and manic symptoms in bipolar disorder as the most important symptomatic contributors to adherence problems in these illnesses. INTERVENTIONS: It is important to identify the specific factors that may be contributing to a patient's adherence problems in order to customize interventions to target those problems. Multiple problems may be involved, requiring a combination of interventions. Conclusions. Adherence problems are complex and multi-determined. The experts recommended customized interventions focused on the underlying causes. Copyright © of content 2009 owned by Comprehensive Neuroscience, Inc