Investigation of CFTR Function in Human Nasal Epithelial Cells Informs Personalized Medicine.

We broaden the clinical versatility of human nasal epithelial (HNE) cells. HNEs were isolated from 10 participants harboring CFTR variants: nine with rare variants (Q359R [n=2], G480S, R334W [n=5], and R560T) and one person harboring R117H;7T;TG10/5T;TG12. Cultures were differentiated at air-liquid interface. CFTR function was measured in Ussing chambers at three conditions - baseline, ivacaftor, and elexacaftor+tezacaftor+ivacaftor (ETI). Four participants initiated modulators. Q359R HNEs had 5.4% (%WT) baseline CFTR function and 25.5% with ivacaftor. With therapy, sweat [Cl-] decreased and symptoms resolved. G480S HNEs had 4.1% baseline and 32.1% CFTR function with ETI. Clinically, FEV1 increased and sweat [Cl-] decreased (119 to 46mmol/L) with ETI. In vitro cultures derived from five individuals harboring R334W showed a moderate increase in CFTR function with exposure to modulators. For one of these participants, ETI was begun in vivo; symptoms and FEV1 improved. c.1679G>C (R560T) HNEs had <4% baseline CFTR function and no modulator response. RNA analysis confirmed that c.1679G>C completely mis-splices. A symptomatic patient harboring R117H;7T;TG10/5T;TG12 exhibited reduced CFTR function (17.5%) in HNEs, facilitating mild CF diagnosis. HNEs responded to modulators (ivacaftor: 32.8%, ETI: 55.5%) and, since beginning therapy, lung function improved. While reaffirming HNE use for guiding therapeutic approaches, we inform predictions on modulator response (e.g. R334W) and closely assess variants affecting splicing (e.g. c.1679G>C). Notably, functional studies in HNEs harboring R117H;7T;TG10/5T;TG12 facilitated mild CF diagnosis, suggesting use for HNE functional studies as a clinical diagnostic test.

Primary amino acid sequences of decapod (Na+, K+)-ATPase provide evolutionary insights into osmoregulatory mechanisms.

Decapod Crustacea exhibit a marine origin, but many taxa have occupied environments ranging from brackish to fresh water and terrestrial habitats, overcoming their inherent osmotic challenges. Osmotic and ionic regulation is achieved by the gill epithelia, driven by two active ATP-hydrolyzing ion transporters, the basal (Na+, K+)-ATPase and the apical V(H+)-ATPase. The kinetic characteristic of gill (Na+, K+)-ATPase and the mRNA expression of its α subunit have been widely studied in various decapod species under different salinity challenges. However, the evolution of the primary structure has not been explored, especially considering the functional modifications associated with decapod phylogeny. Here, we proposed a model for the topology of the decapod α subunit, identifying the sites and motifs involved in its function and regulation, as well as the patterns of its evolution assuming a decapod phylogeny. We also examined both the amino acid substitutions and their functional implications within the context of biochemical and physiological adaptation. The α-subunit of decapod crustaceans shows greater conservation (∼94% identity) compared to the ß-subunit (∼40%). While the binding sites for ATP and modulators are conserved in the decapod enzyme, the residues involved in the α-ß interaction are only partially conserved. In the phylogenetic context of the complete sequence of (Na+, K+)-ATPase α-subunit, most substitutions appear to be characteristic of the entire group, with specific changes for different subgroups, especially among brachyuran crabs. Interestingly, there was no consistent separation of α-subunit partial sequences related to habitat, suggesting that the convergent evolution for freshwater or terrestrial modes of life is not correlated with similar changes in the enzyme's primary amino acid sequence.

Evolutionary trade-offs in osmotic and ionic regulation and expression of gill ion transporter genes in high latitude, cold clime Neotropical crabs from the 'end of the world'.

Osmoregulatory findings on crabs from high Neotropical latitudes are entirely lacking. Seeking to identify the consequences of evolution at low temperature, we examined hyperosmotic/hypo-osmotic and ionic regulation and gill ion transporter gene expression in two sub-Antarctic Eubrachyura from the Beagle Channel, Tierra del Fuego. Despite sharing the same osmotic niche, Acanthocyclus albatrossis tolerates a wider salinity range (2-65‰ S) than Halicarcinus planatus (5-60‰ S); their respective lower and upper critical salinities are 4‰ and 12‰ S, and 63‰ and 50‰ S. Acanthocyclus albatrossis is a weak hyperosmotic regulator, while H. planatus hyperosmoconforms; isosmotic points are 1380 and ∼1340 mOsm kg-1 H2O, respectively. Both crabs hyper/hypo-regulate [Cl-] well with iso-chloride points at 452 and 316 mmol l-1 Cl-, respectively. [Na+] is hyper-regulated at all salinities. mRNA expression of gill Na+/K+-ATPase is salinity sensitive in A. albatrossis, increasing ∼1.9-fold at 5‰ compared with 30‰ S, decreasing at 40-60‰ S. Expression in H. planatus is very low salinity sensitive, increasing ∼4.7-fold over 30‰ S, but decreasing at 50‰ S. V-ATPase expression decreases in A. albatrossis at low and high salinities as in H. planatus. Na+/K+/2Cl- symporter expression in A. albatrossis increases 2.6-fold at 5‰ S, but decreases at 60‰ S versus 30‰ S. Chloride uptake may be mediated by increased Na+/K+/2Cl- expression but Cl- secretion is independent of symporter expression. These unrelated eubrachyurans exhibit similar systemic osmoregulatory characteristics and are better adapted to dilute media; however, the expression of genes underlying ion uptake and secretion shows marked interspecific divergence. Cold clime crabs may limit osmoregulatory energy expenditure by hyper/hypo-regulating hemolymph [Cl-] alone, apportioning resources for other energy-demanding processes.

COVID-19 modifications to a first year medical human anatomy course: Effects on student performance on summative examinations.

The COVID-19 (COVID) pandemic forced changes in how medical curricula are organized and delivered. In addition to disease mitigation strategies, other curricular modifications were required to maintain educational effectiveness and student and faculty safety. While these changes appear to be successful in their primary goal, their effect on learning and other important educational outcomes is less well understood. We describe changes to our anatomy course and describe their effects on summative examination scores. We compared anatomy examination scores from 4 years prior to COVID with scores from the 2 years following COVID mandated changes in an effort to determine the effectiveness of our course modifications. Examination scores for the first of four successive Blocks of instruction following the implementation of curricular changes demonstrated a lower mean score and greater range of scores than for the four pre-COVID years. Pre-COVID and post-COVID scores for Blocks II, III, and IV were comparable. Our results indicate that our changes to the anatomy curriculum did not prevent a performance decline during the first Block of instruction only. However, students were able to successfully adapt to these changes during the remainder of the course. We discuss factors that may have accounted for the Block I performance decline and call attention to changes within the larger curriculum that may have affected student performance.

A method for rewarding collaborative efforts in preclinical assessments.

Student success in basic medical science courses is typically determined by their individual performance on examinations of various types. Previous research both within and outside medical education has shown that the use of educational assessment activities can increase learning as demonstrated by performance on subsequent examinations, a phenomenon known as the testing effect. Activities primarily designed and used for assessment and evaluation purposes can also be used as teaching opportunities. We developed a method for measuring and evaluating student accomplishment in a preclinical basic science course that incorporates both individual and collaborative efforts, encourages and rewards active participation, does not compromise the reliability of the assessment outcome and is perceived by the students as helpful and valuable. The approach involved a two-part assessment activity composed of an individual examination and a small group examination with each component differentially weighted in determining an overall examination score. We found that the method was successful in encouraging collaborative efforts during the group component and provided valid measures of student grasp of the subject matter. We describe the development and implementation of the method, provide data derived from its use in a preclinical basic science course and discuss factors to be addressed when utilizing this approach to ensure fairness and reliability of the outcome. We include brief summary comments from students regarding their impressions of the value of this method.

Horseshoe kidney: Morphologic features, embryologic and genetic etiologies, and surgical implications.

The horseshoe kidney (HSK) is the most common congenital abnormality of the upper urinary tract with an incidence of approximately 1 in 500 in the general population. Although individuals with HSK are often asymptomatic, they are at increased risk for neoplasms, infections, ureteropelvic obstruction secondary to lithiasis or vascular compression. Direct injury from trauma is increased in these individuals as is the risk of intraoperative complications secondary to damage involving the typically complex renal or adrenal vascular supply. We briefly review etiological factors including renal and urinary system embryology, genetic mutations, abnormalities related to faulty cell signaling, aberrant cell migration, and other possible causes including environmental exposures and trauma. In addition, we call attention to factors that might influence the success of surgical procedures in patients with HSK. We argue that an understanding of possible etiologies of the HSK and its different subtypes may be useful when planning surgical procedures or considering risk-benefit ratios associated with different surgical options. We briefly present the organization of a HSK in a 100-year-old male demonstrating an unusual vascular supply discovered during a dissection laboratory session in a medical school anatomy course. We describe the structure of the HSK, the position and relationships of the HSK to other structures within the abdomen, and the associated vascular relationships.

Supporting farmer wellbeing: exploring a potential role for farm advisory staff.

INTRODUCTION: Farmers in Ireland experience poor health outcomes and are considered 'hard to reach'. Agricultural advisors ('advisors') are uniquely positioned to support and signpost farmers on health issues. This paper explores the acceptability and terms of reference of a potential health role for advisors, and offers key recommendations for developing a bespoke farmers' health training programme. METHODS: Following ethical approval, eleven focus groups (n=26 female, n=35 male, age-range 20s-70s) were conducted with farmers (n=4), advisors (n=4), farming organisations (n=2) and farmers' 'significant others' (n=1). Utilizing Thematic Content Analysis, transcripts were coded iteratively and emerging themes were grouped into primary and subthemes. RESULTS: Our analysis identified three themes. 'Scope and acceptability of a potential health role for advisors' examines how participants envision and are receptive to such a role. 'Roles, responsibilities and boundaries' considers both a health promotion and 'health connector' advisory role - normalising health conversations and signposting farmers to services/supports. Finally, 'trouble-shooting potential obstacles to advisors assuming a health role' reflects on the barriers that may impede advisors capacity or potential to have a broader health role. DISCUSSION: Within the context of the stress process theory, findings provide unique insights into how advisory can mediate stress and contribute to farmers' health and wellbeing. Finally, findings have important implications for potentially extending the reach of training to other aspects of farming support services (eg agri-banking, agri-business, veterinary services etc.), as well as serving as a springboard for the development of similar initiatives in other jurisdictions.

Does farming experience matter? A comparison of farm health and safety attitudes, perceptions, and intentions of agricultural science students with and without farming experience.

INTRODUCTION: This study addresses two main questions: 'How does having the experience of farming influence college students' intrinsic motivations towards farm health and safety (FHS)?' and 'Are there any differences between the motivations reported by students with and without having such experience?'. This study seeks to investigate the role of farming experience in students' cognitive factors and intentions to evaluate whether sharing experiences and stories positively shape students' cognitive factors to perform FHS behaviours. METHODS: A cross-sectional online survey using a semi-structured questionnaire was assigned to a nationally representative sample of agricultural science students in Ireland (n= 430). Applying independent sample t-test and ANOVA test, multiple comparisons were made to examine if having the experience of farming affects FHS intrinsic motivations. RESULTS: This study illustrated students without farming experience are less likely to perceive farming as a dangerous occupation while they reported a slightly positive attitude and intention compared with their counterparts with experience of farming. Our study illustrated students with experience of farming gave a lower priority to FHS and control over safety behaviour (pessimistic approach) and they reported a slightly higher level of risk perception (optimistic perception). DISCUSSION: Having experience of farming (destructive experience - the experience of farming without having a near miss or injury or having heard of accidents, ie negative factors affecting students' motivations) may not be necessarily a positive factor as risk-taking is admitted as a norm and a part of the nature of the work. Conversely, having experience of FHS issues (constructive experience - any kind of farming experience that positively shapes students' motivations towards FHS) can positively shape attitude, perceptions, and intention. Therefore, we recommend that constructive experiences (positive affecting intrinsic motivations) should be incorporated into the FHS training of students through peer-to-peer sharing as this enhances attitudes, perceptions, and willingness of the majority of students.

Game Theory in Biology: Moving beyond Functional Accounts.

AbstractThe idea of applying game theory to problems in biology was given a formal basis nearly 50 years ago. Since then, the theory has advanced, and there have been numerous applications of it to a diversity of empirical systems. Most of this work takes a straightforward functional approach, finding a behavioral strategy that is evolutionarily stable in a well-specified specific situation. Relatively little attention has been devoted to the role of phylogeny, the role of learning during development, and the limitations imposed by the psychological and physiological mechanisms that bring about behavior in a complex world. Here I argue that a focus on these elements can improve the link between the theory and empirical systems and hence help us to understand how natural selection has shaped observed behavior.

Social interaction can select for reduced ability.

Animals, including humans, differ in a wide range of physical and cognitive abilities ranging from measures of running speed and physical strength to learning ability and intelligence. We consider the evolution of ability when individuals interact pairwise over their contribution to a common good. In this interaction, the contribution of each is assumed to be the best given their own ability and the contribution of their partner. Since there is a tendency for individuals to partially compensate for a low contribution by their partner, low-ability individuals can do well. As a consequence, for benefit and cost structures for which individuals have a strong response to partner's contribution, there can be selection for reduced ability. Furthermore, there can be disruptive selection on ability, leading to a bimodal distribution of ability under some modes of inheritance.

Behavioural specialization and learning in social networks.

Interactions in social groups can promote behavioural specialization. One way this can happen is when individuals engage in activities with two behavioural options and learn which option to choose. We analyse interactions in groups where individuals learn from playing games with two actions and negatively frequency-dependent payoffs, such as producer-scrounger, caller-satellite, or hawk-dove games. Group members are placed in social networks, characterized by the group size and the number of neighbours to interact with, ranging from just a few neighbours to interactions between all group members. The networks we analyse include ring lattices and the much-studied small-world networks. By implementing two basic reinforcement-learning approaches, action-value learning and actor-critic learning, in different games, we find that individuals often show behavioural specialization. Specialization develops more rapidly when there are few neighbours in a network and when learning rates are high. There can be learned specialization also with many neighbours, but we show that, for action-value learning, behavioural consistency over time is higher with a smaller number of neighbours. We conclude that frequency-dependent competition for resources is a main driver of specialization. We discuss our theoretical results in relation to experimental and field observations of behavioural specialization in social situations.

An evolutionary perspective on stress responses, damage and repair.

Variation in stress responses has been investigated in relation to environmental factors, species ecology, life history and fitness. Moreover, mechanistic studies have unravelled molecular mechanisms of how acute and chronic stress responses cause physiological impacts ('damage'), and how this damage can be repaired. However, it is not yet understood how the fitness effects of damage and repair influence stress response evolution. Here we study the evolution of hormone levels as a function of stressor occurrence, damage and the efficiency of repair. We hypothesise that the evolution of stress responses depends on the fitness consequences of damage and the ability to repair that damage. To obtain some general insights, we model a simplified scenario in which an organism repeatedly encounters a stressor with a certain frequency and predictability (temporal autocorrelation). The organism can defend itself by mounting a stress response (elevated hormone level), but this causes damage that takes time to repair. We identify optimal strategies in this scenario and then investigate how those strategies respond to acute and chronic exposures to the stressor. We find that for higher repair rates, baseline and peak hormone levels are higher. This typically means that the organism experiences higher levels of damage, which it can afford because that damage is repaired more quickly, but for very high repair rates the damage does not build up. With increasing predictability of the stressor, stress responses are sustained for longer, because the animal expects the stressor to persist, and thus damage builds up. This can result in very high (and potentially fatal) levels of damage when organisms are exposed to chronic stressors to which they are not evolutionarily adapted. Overall, our results highlight that at least three factors need to be considered jointly to advance our understanding of how stress physiology has evolved: (i) temporal dynamics of stressor occurrence; (ii) relative mortality risk imposed by the stressor itself versus damage caused by the stress response; and (iii) the efficiency of repair mechanisms.

Perioperative Management of the Fontan Patient for Cardiac and Noncardiac Surgery.

The Fontan circulation is the single-ventricle approach to surgical palliation of complex congenital heart disease wherein biventricular separation and function cannot be safely achieved. Incremental improvements in this surgical technique, along with improvements in the long-term medical management of these patients, have led to greater survival of these patients and a remarkably steady increase in the number of adults living with this unusual circulation and physiology. This has implications for healthcare providers who now have a greater chance of encountering Fontan patients during the course of their practice. This has particularly important implications for anesthesiologists because the effects of their interventions on the finely balanced Fontan circulation may be profound. The American Heart Association and American College of Cardiology recommend that, when possible, elective surgery should be performed in an adult congenital heart disease center, although this may not be feasible in the provision of true emergency care. This review article summarizes the pathophysiology pertinent to the provision of anesthesia in this complex patient group and describes important modifications to anesthetic technique and perioperative management.

An approach to determining, delivering, and assessing essential course content in a medical human anatomy course.

Learning objectives typically indicate subject matter judged to be important or that represents essential material to be learned during a course. We report here on our efforts to identify essential course content and determine our effectiveness teaching and assessing this content in our preclinical human anatomy course. Using a consensus driven approach, we identified anatomical structures, relationships, and functional concepts judged to represent essential material in our unit on the thorax that students were expected to be familiar with. We then determined performance on specific examination questions that focused directly on the essential material. Thirty-seven of 48 students (77%) correctly answered all 34 of 51 questions that directly focused on content we defined as essential. The remaining 11 students answered the majority of these questions correctly. The overall mean score was 86% (range 61%-98%). Our review of student performance on the End of Block thorax examination confirmed our belief that we were successful in helping students learn material we defined as essential. We found the process described here to be helpful in defining essential content and for helping focus and improve medical education and learning assessment based on that material. We believe the idea of defining essential content that can be efficiently taught and effectively learned within a proscribed period of time is an important and necessary objective. We believe the approach used here might be successfully utilized in other programs in efforts aimed at quality improvement.

Anatomy of the physical examination: A small group learning approach for increasing engagement and learning in a medical gross anatomy course.

The ability to perform and interpret the physical examination requires an understanding of human anatomy and how to apply that content in the clinical setting. Previous work has shown that students understand and retain information more effectively when they are actively engaged in the learning process and it is clearly linked to other coursework and their future needs. We developed a series of learning activities, based on the general physical examination, designed to enhance engagement and encourage durable learning of anatomical principles that are important in performing and interpreting the physical examination. Activities were designed for use in small group settings with faculty supervision and input as needed. We describe these activities and provide comments from students regarding the perceived value of these learning activities. Students reported that the applied anatomy learning activities were engaging and aided in their learning of human anatomy. Additionally, students appreciated the connection between the applied anatomy activities and the skills being learned in concurrent coursework focusing on the physical examination. We observed that applied human anatomy exercises modeled after components of the general physical examination and embedded in an anatomy course enhanced student engagement and helped students appreciate the importance of anatomical principles. We note that sensitivity to and acceptance of personal preferences and religious matters must be shown when using learning activities that involve close physical interactions to teach anatomical topics.

Small group learning/assessment sessions: A method using test enhanced learning to increase engagement in a basic medical science neuroanatomy course.

Previous research has shown that test-enhanced learning with structured feedback facilitates durable learning. We describe a small group learning/assessment activity using these approaches intended to increase engagement and engagement with the course material. We divided our class into six groups of seven students each that worked together in the activity. During each weekly session, course related multiple choice questions were projected and each group instructed to work independently to arrive at a consensus answer for each question. After each question is considered, a faculty facilitator then randomly selects one group to share their choice with the other groups and provide and rationale for their choice. A different group or groups are then called upon to share their choice. When differences emerge, the instructor then facilitates discussion among the groups in an effort to resolve confusion or incomplete or incorrect understanding that becomes evident. We found that attendance for these sessions was greater than for the more traditional lecture based session also included in the course and that students were actively engaged in this learning activity. The success of the small group learning/assessment session is dependent on several factors including the difficulty of the questions and their relatedness to the course objectives, the timing and placement of the session or sessions within the course and the skill of the faculty facilitator in encouraging active participation while ensuring a safe environment in which students can openly share their sometimes incomplete or incorrect understanding of the material.

Acute Myocardial Infarction and Community-acquired Staphylococcus aureus Bloodstream Infection: An Observational Cohort Study.

BACKGROUND: The relationship between acute myocardial infarction and infection was recognized in the early 20th century during influenza epidemics. Most recently, a case control study and a self-control design study have identified an association between Staphylococcus aureus infection and acute myocardial infarction. We assessed the association of community-acquired Staphylococcus aureus bloodstream infection (CA-SABSI) and myocardial infarction in the 365 days following blood culture. METHODS: This was a cohort study assessing the incidence of myocardial infarction 365 days after blood culture for Staphylococcus aureus. Culture-negative patients had blood cultures collected at hospital attendance and were matched to the CA-SABSI participants by sex, 5-year age strata, and year of culture collection. Pathology information was linked to hospital administrative data and index of relative socioeconomic advantage and disadvantage (ISRAD). RESULTS: The study included 5157 CA-SABSI cases matched to 10 146 blood culture-negative cases. The mortality rate was significantly higher in the CA-SABSI group (10.9%; 562/5157) than in culture-negative cases (5.1%; 521/10 146) at 365 days (P < .0001). In the 7 days following the index blood culture, excluding recurrent events, there were 89 (1.7%) and 37 (.4%) myocardial infarction diagnoses in the CA-SABSI and culture-negative cases, respectively. Multivariable logistic regression for myocardial infarction demonstrated a significant association with CA-SABSI after adjusting for known risk factors (odds ratio [OR], 5; 95% confidence interval [CI], 3.3-7.5; P < .0001). Myocardial infarctions occurring in this short-term risk period were associated with all-cause mortality in a Cox proportional hazard model (OR, 1.7; 95% CI, 1.2-2.4; P < .005). CONCLUSIONS: CA-SABSI is associated with an increased short-term risk of myocardial infarction, which is associated with subsequent mortality.

Contrasting strategies of osmotic and ionic regulation in freshwater crabs and shrimps: gene expression of gill ion transporters.

Owing to their extraordinary niche diversity, the Crustacea are ideal for comprehending the evolution of osmoregulation. The processes that effect systemic hydro-electrolytic homeostasis maintain hemolymph ionic composition via membrane transporters located in highly specialized gill ionocytes. We evaluated physiological and molecular hyper- and hypo-osmoregulatory mechanisms in two phylogenetically distant, freshwater crustaceans, the crab Dilocarcinus pagei and the shrimp Macrobrachium jelskii, when osmotically challenged for up to 10 days. When in distilled water, D. pagei survived without mortality, hemolymph osmolality and [Cl-] increased briefly, stabilizing at initial values, while [Na+] decreased continually. Expression of gill V-type H+-ATPase (V-ATPase), Na+/K+-ATPase and Na+/K+/2Cl- symporter genes was unchanged. In M. jelskii, hemolymph osmolality, [Cl-] and [Na+] decreased continually for 12 h, the shrimps surviving only around 15-24 h exposure. Gill transporter gene expression increased 2- to 5-fold. After 10 days exposure to brackish water (25‰S), D. pagei was isosmotic, iso-chloremic and iso-natriuremic. Gill V-ATPase expression decreased while Na+/K+-ATPase and Na+/K+/2Cl- symporter expression was unchanged. In M. jelskii (20‰S), hemolymph was hypo-regulated, particularly [Cl-]. Transporter expression initially increased 3- to 12-fold, declining to control values. Gill V-ATPase expression underlies the ability of D. pagei to survive in fresh water while V-ATPase, Na+/K+-ATPase and Na+/K+/2Cl- symporter expression enables M. jelskii to confront hyper/hypo-osmotic challenges. These findings reveal divergent responses in two unrelated crustaceans inhabiting a similar osmotic niche. While D. pagei does not secrete salt, tolerating elevated cellular isosmoticity, M. jelskii exhibits clear hypo-osmoregulatory ability. Each species has evolved distinct strategies at the transcriptional and systemic levels during its adaptation to fresh water.

A Review of Heart Transplantation for Adults With Congenital Heart Disease.

As techniques for corrective and palliative surgery in congenital heart disease improve, the number of patients surviving to become adults with congenital heart disease (ACHD) has increased. A significant proportion of these patients will progress to develop advanced heart failure, the symptoms of which vary, complicating prediction of life expectancy. Unlike acquired heart failure, there is a lack of evidence-based treatments with which to relieve symptoms and prolong survival. As a result, a number of ACHD patients will proceed to heart transplantation. Referral for transplantation should be considered early, given the difficulties with prognostication, and should take place in a center with surgical and medical expertise in the management of ACHD patients and transplantation. In addition to assessing contraindications to heart transplantation for the general population, factors specific to ACHD should be considered. These include pulmonary hypertension, cyanosis, liver disease, previous surgeries, and the degree of allosensitization. Once listed for transplantation, ACHD patients spend longer on the waitlist, and are more likely to die or be delisted than their non-ACHD counterparts. Mechanical circulatory support is used less commonly as a bridge to transplantation given the difficulties with implantation and unfamiliarity of use. Recent evidence suggests that with increased experience and early consideration, mechanical circulatory support can be used successfully as a bridging therapy. Despite a higher early mortality, long-term survival is greater for ACHD patients after transplant due to younger age and relative lack of comorbidities. With early referral, careful assessment of each individual's unique anatomy and physiology, and care in a center experienced with ACHD patients and transplantation, outcomes will continue to improve.

Salt transport by the gill Na+-K+-2Cl- symporter in palaemonid shrimps: exploring physiological, molecular and evolutionary landscapes.

Palaemonid shrimps inhabit osmotic niches from marine to continental waters. They hyper-regulate hemolymph osmolality and ionic concentrations in dilute media, hypo-regulating in concentrated media. Their gill epithelia express ion transporters like the Na+-K+-2Cl- symporter (NKCC) thought to play a role in salt secretion. To examine Cl- hypo-regulatory capability and phylogenetic correlations between gill NKCC mRNA levels and protein expression, we used palaemonids ranging from marine tide pools through estuaries (Palaemon) to coastal and continental fresh waters (Macrobrachium). We established the species' upper critical salinity limits (UL50) and short- (24 h) and long-term (120h) hypo-regulatory abilities at salinities of 80% of their UL50's (80%UL50). The Palaemon species exhibited the highest UL50's and greatest hypo-regulatory capabilities; among the Macrobrachium species, UL50's were higher in the diadromous than in the hololimnetic species. While basal transcript levels of gill NKCC mRNA were highest in P. pandaliformis, levels were unaffected by salinity or exposure time in all species. However, gill NKCC protein abundance increased after 120-h exposure at the 80%UL50 in all Macrobrachium species, except M. potiuna. Unexpectedly, hemolymph hyper-osmoregulatory capability in acclimatization media correlated with gill NKCC protein synthesis, while gill NKCC mRNA expression correlated with hemolymph hyper-Cl- regulation in Macrobrachium. These findings, together with the evolutionary history of osmoregulation in this shrimp clade, suggest a role for the gill NKCC symporter in both salt uptake and secretion. The evolution of NKCC protein expression responsiveness, unlike hemolymph hypo-regulation and NKCC mRNA expression, may have been driven by environmental salinity during niche radiation. SUMMARY STATEMENT: While mRNA expression of the gill Na+-K+-2Cl- symporter is unchanged during acclimation of palaemonid shrimps to saline media, protein expression is up regulated, revealing a role in chloride secretion.