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1.
Arthrosc Tech ; 13(5): 102953, 2024 May.
Article En | MEDLINE | ID: mdl-38835446

Subscapularis insufficiency continues to be a source of morbidity after anatomic total shoulder arthroplasty (TSA). Biologic augmentation following rotator cuff repair has shown promising results. Here we show the technique for performing subscapularis repair after anatomic TSA using a "peel-tenotomy" and bone marrow aspirate concentrate (BMAC). A standard deltopectoral approach is performed. The peel-tenotomy is performed by leaving 0 to 10 mm of subscapularis attached to the lesser tuberosity and peeling off the remainder of the tendon. A trocar is used to aspirate bone marrow from the humeral head, which is then processed. Prior to placing the humeral stem, drill holes are placed at the bicipital groove and lesser tuberosity. Sutures are placed through each drill hole. After impacting the humeral stem, suture is passed through the subscapularis to perform a secure double row repair. Prior to tying the sutures, BMAC is applied along the margins of the subscapularis repair. After securing the sutures, additional BMAC can be applied to the subscapularis repair. It is hypothesized that this technique could provide a more robust subscapularis repair and decrease the rate of subscapularis insufficiency after TSA without any known risk or morbidity to the patient, although further research is needed to show this.

2.
bioRxiv ; 2024 May 03.
Article En | MEDLINE | ID: mdl-38746263

Grover disease is an acquired dermatologic disorder characterized by pruritic vesicular and eroded skin lesions. While its pathologic features are well-defined, including impaired cohesion of epidermal keratinocytes, the etiology of Grover disease remains unclear and it lacks any FDA-approved therapy. Interestingly, drug-induced Grover disease occurs in patients treated with B-RAF inhibitors that can paradoxically activate C-RAF and the downstream kinase MEK. We recently identified hyperactivation of MEK and ERK as key drivers of Darier disease, which is histologically identical to Grover disease, supporting our hypothesis that they share a pathogenic mechanism. To model drug-induced Grover disease, we treated human keratinocytes with clinically utilized B-RAF inhibitors dabrafenib or vemurafenib and leveraged a fluorescent biosensor to confirm they activated ERK, which disrupted intercellular junctions and compromised keratinocyte sheet integrity. Consistent with clinical data showing concomitant MEK blockade prevents Grover disease in patients receiving B-RAF inhibitors, we found that MEK inhibition suppressed excess ERK activity to rescue cohesion of B-RAF-inhibited keratinocytes. Validating these results, we demonstrated ERK hyperactivation in skin biopsies of vemurafenib-induced Grover disease, but also in spontaneous Grover disease. In sum, our data define a pathogenic role for ERK hyperactivation in Grover disease and support MEK inhibition as a therapeutic strategy.

3.
Proc Biol Sci ; 291(2023): 20232849, 2024 May.
Article En | MEDLINE | ID: mdl-38775542

Recent experiments have demonstrated that carnivores and ungulates in Africa, Asia, Europe and North America fear the human 'super predator' far more than other predators. Australian mammals have been a focus of research on predator naiveté because it is suspected they show atypical antipredator responses. To experimentally test if mammals in Australia also most fear humans, we quantified the responses of four native marsupials (eastern grey kangaroo, Bennett's wallaby, Tasmanian pademelon, common brushtail possum) and introduced fallow deer to playbacks of predator (human, dog, Tasmanian devil, wolf) or non-predator control (sheep) vocalizations. Native marsupials most feared the human 'super predator', fleeing humans 2.4 times more often than the next most frightening predator (dogs), and being most, and significantly, vigilant to humans. These results demonstrate that native marsupials are not naïve to the peril humans pose, substantially expanding the taxonomic and geographic scope of the growing experimental evidence that wildlife worldwide generally perceive humans as the planet's most frightening predator. Introduced fallow deer fled humans, but not more than other predators, which we suggest may result from their being introduced. Our results point to both challenges concerning marsupial conservation and opportunities for exploiting fear of humans as a wildlife management tool.


Deer , Fear , Marsupialia , Predatory Behavior , Animals , Deer/physiology , Humans , Marsupialia/physiology , Australia , Introduced Species , Wolves/physiology , Dogs , Vocalization, Animal
4.
Cureus ; 16(4): e59400, 2024 Apr.
Article En | MEDLINE | ID: mdl-38817469

Colonic lipomas are benign masses typically found incidentally during routine screening exams. They rarely grow large enough to become symptomatic. While most colonic lipomas are small and do not lead to complications, giant lipomas can present with symptoms ranging from changes in bowel patterns and mild abdominal pain to bowel obstruction. Ulcerated giant colonic lipomas are even more rare findings on screening colonoscopies. Diagnosis in this context can be challenging, and resection is warranted in most cases. Here, we describe an asymptomatic patient who presented for a screening colonoscopy and was found to have a giant ulcerated colonic lipoma.

5.
J Phys Chem A ; 128(21): 4268-4278, 2024 May 30.
Article En | MEDLINE | ID: mdl-38752426

New particle formation (NPF) is the process by which trace atmospheric acids and bases cluster and grow into particles that ultimately impact climate. Sulfuric acid concentration drives NPF, but nitrogen-containing bases promote the formation of more stable clusters via salt bridge formation. Recent computational efforts have suggested that amino acids can enhance NPF, predicting that they can stabilize new particles via multiple protonation sites, but there has yet to be experimental validation of these predictions. We used mass spectrometry and infrared spectroscopy to study the structure and stability of cationic clusters composed of glycine, sulfuric acid, and ammonia. When collisionally activated, clusters were significantly more likely to eliminate ammonia or sulfuric acid than glycine, while quantum chemical calculations predicted lower binding free energies for ammonia but similar binding free energies for glycine and sulfuric acid. These calculations predicted several low-energy structures, so we compared experimental and computed vibrational spectra to attempt to validate the computationally predicted minimum energy structure. Unambiguous identification of the experimental structure by comparison to these calculations was made difficult by the complexity of the experimental spectra and the fact that the identity of the computed lowest-energy structure depended strongly on temperature. If their vapors are present, amino acids are likely to be enriched in new particles by displacing more weakly bound ammonia, similar to the behavior of other atmospheric amines. The carboxylic acid groups were found to preferentially interact with other carboxylic acids, suggesting incipient organic/inorganic phase separation even at these small sizes.

6.
J Clin Monit Comput ; 2024 May 11.
Article En | MEDLINE | ID: mdl-38733507

PURPOSE: The compensatory reserve metric (CRM) is a novel tool to predict cardiovascular decompensation during hemorrhage. The CRM is traditionally computed using waveforms obtained from photoplethysmographic volume-clamp (PPGVC), yet invasive arterial pressures may be uniquely available. We aimed to examine the level of agreement of CRM values computed from invasive arterial-derived waveforms and values computed from PPGVC-derived waveforms. METHODS: Sixty-nine participants underwent graded lower body negative pressure to simulate hemorrhage. Waveform measurements from a brachial arterial catheter and PPGVC finger-cuff were collected. A PPGVC brachial waveform was reconstructed from the PPGVC finger waveform. Thereafter, CRM values were computed using a deep one-dimensional convolutional neural network for each of the following source waveforms; (1) invasive arterial, (2) PPGVC brachial, and (3) PPGVC finger. Bland-Altman analyses were used to determine the level of agreement between invasive arterial CRM values and PPGVC CRM values, with results presented as the Mean Bias [95% Limits of Agreement]. RESULTS: The mean bias between invasive arterial- and PPGVC brachial CRM values at rest, an applied pressure of -45mmHg, and at tolerance was 6% [-17%, 29%], 1% [-28%, 30%], and 0% [-25%, 25%], respectively. Additionally, the mean bias between invasive arterial- and PPGVC finger CRM values at rest, applied pressure of -45mmHg, and tolerance was 2% [-22%, 26%], 8% [-19%, 35%], and 5% [-15%, 25%], respectively. CONCLUSION: There is generally good agreement between CRM values obtained from invasive arterial waveforms and values obtained from PPGVC waveforms. Invasive arterial waveforms may serve as an alternative for computation of the CRM.

7.
Laryngoscope ; 2024 May 13.
Article En | MEDLINE | ID: mdl-38738808

A variety of surgical treatment options exist for adductor spasmodic dysphonia (ADSD) with selective adductor recurrent laryngeal nerve denervation and reinnervation (SLAD-R) being one of the more popular. We present a case of bilateral vocal fold paralysis (BVFP) for SLAD-R resulting in the need for total laryngectomy. We suggest BVFP is more common than reported and that we all must insure optimal long term follow up of our surgical patients. Laryngoscope, 2024.

8.
Sci Rep ; 14(1): 8719, 2024 04 15.
Article En | MEDLINE | ID: mdl-38622207

Occult hemorrhages after trauma can be present insidiously, and if not detected early enough can result in patient death. This study evaluated a hemorrhage model on 18 human subjects, comparing the performance of traditional vital signs to multiple off-the-shelf non-invasive biomarkers. A validated lower body negative pressure (LBNP) model was used to induce progression towards hypovolemic cardiovascular instability. Traditional vital signs included mean arterial pressure (MAP), electrocardiography (ECG), plethysmography (Pleth), and the test systems utilized electrical impedance via commercial electrical impedance tomography (EIT) and multifrequency electrical impedance spectroscopy (EIS) devices. Absolute and relative metrics were used to evaluate the performance in addition to machine learning-based modeling. Relative EIT-based metrics measured on the thorax outperformed vital sign metrics (MAP, ECG, and Pleth) achieving an area-under-the-curve (AUC) of 0.99 (CI 0.95-1.00, 100% sensitivity, 87.5% specificity) at the smallest LBNP change (0-15 mmHg). The best vital sign metric (MAP) at this LBNP change yielded an AUC of 0.6 (CI 0.38-0.79, 100% sensitivity, 25% specificity). Out-of-sample predictive performance from machine learning models were strong, especially when combining signals from multiple technologies simultaneously. EIT, alone or in machine learning-based combination, appears promising as a technology for early detection of progression toward hemodynamic instability.


Cardiovascular System , Hypovolemia , Humans , Hypovolemia/diagnosis , Lower Body Negative Pressure , Vital Signs , Biomarkers
9.
Clin Spine Surg ; 2024 Apr 09.
Article En | MEDLINE | ID: mdl-38637934

STUDY DESIGN: Retrospective case series. OBJECTIVE: Describe the injury characteristics of ballistic fractures involving the atlantoaxial spine. SUMMARY OF BACKGROUND DATA: Civilian gunshot wounds to the spine are an increasingly common injury in the United States. Civilian studies have focused on ballistic injuries to the entire spine as opposed to a region-specific fashion. Only a single 10-patient case series investigating ballistic fractures to the upper cervical spine (C1 and C2) exists, leaving a large gap in the understanding of this injury complex. METHODS: A retrospective chart review was performed. Extracted data included patient demographics, neurological status on presentation, fracture morphology, assessment of stability, other associated injuries, and surgical procedures performed. Proportional analysis was performed to characterize the fractures and their associated neurological injuries. RESULTS: Thirty-six patients were identified, with 86% being male with an average patient age of 30.0 ± 10.36 years (mean ± SD). Fracture morphology was characterized using proportional analysis. Initial neurological exams were either ASIA A or ASIA E, without any incomplete injuries noted. Patients who sustained a transcanal injury did not show any neurological improvement. The initial in-hospital mortality rate was 5.6%, with a 1-year mortality rate of 8.3%. There is a high incidence of associated vascular injury (66%) and mandible fracture (33%). CONCLUSIONS: Ballistic penetrating trauma to the atlantoaxial spine often results in complex injury patterns necessitating multidisciplinary care with high rates of morbidity and mortality. If neurological deficits are present initially, they are often complete. Two thirds of patients sustained an associated vascular injury, which should be screened for with CT angiography.

10.
bioRxiv ; 2024 Mar 11.
Article En | MEDLINE | ID: mdl-38559144

Vertebrates and tunicates are sister groups that share a common fusogenic factor, Myomaker (Mymk), that drives myoblast fusion and muscle multinucleation. Yet they are divergent in when and where they express Mymk. In vertebrates, all developing skeletal muscles express Mymk and are obligately multinucleated. In tunicates, Mymk is only expressed in post-metamorphic multinucleated muscles, but is absent from mononucleated larval muscles. In this study, we demonstrate that cis-regulatory sequence differences in the promoter region of Mymk underlie the different spatiotemporal patterns of its transcriptional activation in tunicates and vertebrates. While in vertebrates Myogenic Regulatory Factors (MRFs) like MyoD1 alone are required and sufficient for Mymk transcription in all skeletal muscles, we show that transcription of Mymk in post-metamorphic muscles of the tunicate Ciona requires the combinatorial activity of MRF/MyoD and Early B-Cell Factor (Ebf). This macroevolutionary difference appears to be encoded in cis, likely due to the presence of a putative Ebf binding site adjacent to predicted MRF binding sites in the Ciona Mymk promoter. We further discuss how Mymk and myoblast fusion might have been regulated in the last common ancestor of tunicates and vertebrates, for which we propose two models.

11.
J Med Chem ; 67(6): 4655-4675, 2024 Mar 28.
Article En | MEDLINE | ID: mdl-38462716

The ubiquitously expressed protein tyrosine phosphatase SHP2 is required for signaling downstream of receptor tyrosine kinases (RTKs) and plays a role in regulating many cellular processes. Genetic knockdown and pharmacological inhibition of SHP2 suppresses RAS/MAPK signaling and inhibit the proliferation of RTK-driven cancer cell lines. Here, we describe the first reported fragment-to-lead campaign against SHP2, where X-ray crystallography and biophysical techniques were used to identify fragments binding to multiple sites on SHP2. Structure-guided optimization, including several computational methods, led to the discovery of two structurally distinct series of SHP2 inhibitors binding to the previously reported allosteric tunnel binding site (Tunnel Site). One of these series was advanced to a low-nanomolar lead that inhibited tumor growth when dosed orally to mice bearing HCC827 xenografts. Furthermore, a third series of SHP2 inhibitors was discovered binding to a previously unreported site, lying at the interface of the C-terminal SH2 and catalytic domains.


Neoplasms , Protein Tyrosine Phosphatase, Non-Receptor Type 11 , Humans , Mice , Animals , Signal Transduction , Receptor Protein-Tyrosine Kinases/metabolism , Allosteric Site
12.
Environ Manage ; 73(5): 1049-1071, 2024 May.
Article En | MEDLINE | ID: mdl-38520553

As human activity accelerates the global crisis facing wildlife populations, private land conservation provides an example of wildlife management challenges in social-ecological systems. This study reports on the research phase of 'WildTracker' - a co-created citizen science project, involving 160 landholders across three Tasmanian regions. This was a transdisciplinary collaboration between an environmental organisation, university researchers, and local landholders. Focusing on mammal and bird species, the project integrated diverse data types and technologies: social surveys, quantitative ecology, motion sensor cameras, acoustic recorders, and advanced machine-learning analytics. An iterative analytical methodology encompassed Pearson and point-biserial correlation for interrelationships, Non-Metric Multidimensional Scaling (NMDS) for clustering, and Random Forest machine learning for variable importance and prediction. Taken together, these analyses revealed complex relationships between wildlife populations and a suite of ecological, socio-economic, and land management variables. Both site-scale habitat characteristics and landscape-scale vegetation patterns were useful predictors of mammal and bird activity, but these relationships were different for mammals and birds. Four focal mammal species showed variation in their response to ecological and land management drivers. Unexpectedly, threatened species, such as the eastern quoll (Dasyurus viverrinus), favoured locations where habitat was substantially modified by human activities. The research provides actionable insights for landowners, and highlights the importance of 'messy,' ecologically heterogeneous, mixed agricultural landscapes for wildlife conservation. The identification of thresholds in habitat fragmentation reinforced the importance of collaboration across private landscapes. Participatory research models such as WildTracker can complement efforts to address the wicked problem of wildlife conservation in the Anthropocene.


Animals, Wild , Conservation of Natural Resources , Animals , Humans , Ecosystem , Agriculture , Mammals , Biodiversity
13.
Infect Dis Ther ; 13(4): 633-645, 2024 Apr.
Article En | MEDLINE | ID: mdl-38461480

INTRODUCTION: This prospective, longitudinal, community-based study, EpidemiologiCal POpulatioN STudy of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Lake CounTy, Illinois (CONTACT), investigated coronavirus disease 2019 (COVID-19) immunity, occupational risks related to SARS-CoV-2 exposure, and long-term immunoglobulin G (IgG) seroconversion kinetics. METHODS: At baseline and follow up (3, 6, and 9 months), non-hospitalized adult participants provided nasal and blood serum specimens for molecular [reverse transcription polymerase chain reaction (RT-PCR)] and serological (IgG) testing (4 November 2020-30 October 2021). RESULTS: At baseline, 6.4% (65/1008) had evidence of current/prior SARS-CoV-2 infection. At 3, 6, and 9 months, positive PCR tests were obtained from 0.4% (3/781), 0.4% (3/733), and 0% (0/673) of participants, respectively. Positive IgG occurred at baseline and 3, 6, and 9 months in 4.5% (45/1008), 6.0% (48/799), 5.4% (39/733), and 2.8% (19/673) of participants, respectively. Of participants positive for IgG at baseline, 28 had a negative IgG test at a follow-up visit; of those 28, 21 had their first negative IgG test within 6 months. Participants were more likely to retain positive IgG if they were 18-29 years of age, were male, or had medium-high/high-risk occupations. A high vaccination rate (70% received ≥ 1 dose by 9 months) was observed. Influence of occupational status or characteristics on transmission and IgG, and COVID-19 vaccination trends, are shown. CONCLUSIONS: This study expands on prior studies assessing COVID-19 immunity and IgG seroconversion by including both RT-PCR and serologic testing and longitudinal follow-up of study participants. We observed decreased infection rates over the 9 month follow-up period as well as a decline in IgG persistency after 6 months. The findings from this community-based study regarding vaccinate rates, infection rates by PCR, and IgG persistency over time can help improve our understanding of COVID-19 immunity, occupational risks related to SARS-CoV-2 exposure, and the kinetics of long-term IgG seroconversion, which is important to help guide local and national mitigation strategies. CLINICAL TRIAL REGISTRATION: NCT04611230.

14.
PLoS Biol ; 22(3): e3002555, 2024 Mar.
Article En | MEDLINE | ID: mdl-38478577

The papillae of tunicate larvae contribute sensory, adhesive, and metamorphosis-regulating functions that are crucial for the biphasic lifestyle of these marine, non-vertebrate chordates. We have identified additional molecular markers for at least 5 distinct cell types in the papillae of the model tunicate Ciona, allowing us to further study the development of these organs. Using tissue-specific CRISPR/Cas9-mediated mutagenesis and other molecular perturbations, we reveal the roles of key transcription factors and signaling pathways that are important for patterning the papilla territory into a highly organized array of different cell types and shapes. We further test the contributions of different transcription factors and cell types to the production of the adhesive glue that allows for larval attachment during settlement, and to the processes of tail retraction and body rotation during metamorphosis. With this study, we continue working towards connecting gene regulation to cellular functions that control the developmental transition between the motile larva and sessile adult of Ciona.


Urochordata , Animals , Urochordata/genetics , Urochordata/metabolism , Adhesives/metabolism , Larva , Biomarkers/metabolism , Transcription Factors/metabolism , Metamorphosis, Biological
15.
Can J Cardiol ; 2024 Feb 07.
Article En | MEDLINE | ID: mdl-38331027

BACKGROUND: We sought to improve the immediate and subsequent care of emergency department (ED) patients with acute atrial fibrillation (AF) and flutter (AFL) by implementing the principles of the Canadian Association of Emergency Physicians AF/AFL Best Practices Checklist. METHODS: This cohort study included 3 periods: before (7 months), intervention introduction (1 month), and after (7 months), and was conducted at a major academic centre. We included patients who presented with an episode of acute AF or AFL and used multiple strategies to support ED adoption of the Canadian Association of Emergency Physicians checklist. We developed new cardiology rapid-access follow-up processes. The main outcomes were unsafe and suboptimal treatments in the ED. RESULTS: We included 1108 patient visits, with 559 in the before and 549 in the after period. In a comparison of the periods, there was an increase in use of chemical cardioversion (20.6% vs 25.0%; absolute difference [AD], 4.4%) and in electrical cardioversion (39.2% vs 51.2%; AD, 12.0%). More patients were discharged with sinus rhythm restored (66.9% vs 75.0%; AD, 8.1%). The proportion seen in a follow-up cardiology clinic increased from 24.2% to 39.9% (AD, 15.7%) and the mean time until seen decreased substantially (103.3 vs 49.0 days; AD, -54.3 days). There were very few unsafe cases (0.4% vs 0.7%) and, although there was an increase in suboptimal care (19.5% vs 23.1%), overall patient outcomes were excellent. CONCLUSIONS: We successfully improved the care for ED patients with acute AF/AFL and achieved more frequent and more rapid cardiology follow-up. Although cases of unsafe management were uncommon and patient outcomes were excellent, there are opportunities for physicians to improve their care of acute AF/AFL patients. GOV IDENTIFIER: NCT05468281.

16.
medRxiv ; 2024 Feb 05.
Article En | MEDLINE | ID: mdl-38370760

Background: Long QT syndrome (LQTS) is a lethal arrhythmia condition, frequently caused by rare loss-of-function variants in the cardiac potassium channel encoded by KCNH2. Variant-based risk stratification is complicated by heterogenous clinical data, incomplete penetrance, and low-throughput functional data. Objective: To test the utility of variant-specific features, including high-throughput functional data, to predict cardiac events among KCNH2 variant heterozygotes. Methods: We quantified cell-surface trafficking of 18,323 variants in KCNH2 and recorded potassium current densities for 506 KCNH2 variants. Next, we deeply phenotyped 1150 KCNH2 missense variant patients, including ECG features, cardiac event history (528 total cardiac events), and mortality. We then assessed variant functional, in silico, structural, and LQTS penetrance data to stratify event-free survival for cardiac events in the study cohort. Results: Variant-specific current density (HR 0.28 [0.13-0.60]) and estimates of LQTS penetrance incorporating MAVE data (HR 3.16 [1.59-6.27]) were independently predictive of severe cardiac events when controlling for patient-specific features. Risk prediction models incorporating these data significantly improved prediction of 20 year cardiac events (AUC 0.79 [0.75-0.82]) over patient-only covariates (QTc and sex) (AUC 0.73 [0.70-0.77]). Conclusion: We show that high-throughput functional data, and other variant-specific features, meaningfully contribute to both diagnosis and prognosis of a clinically actionable monogenic disease.

17.
Vaccine ; 42(7): 1682-1689, 2024 Mar 07.
Article En | MEDLINE | ID: mdl-38360478

In 2013, shingles vaccination was introduced in Wales as a routine immunisation programme for older adults. Invitation for this vaccination has historically been recommended but not mandated by vaccination policy. We surveyed general practices to investigate if invitations and reminders are associated with higher uptake of shingles vaccine. Using data from general practices, we calculated practice-level shingles vaccine uptake between 01/07/2021 and 31/06/2022 for registered patients aged 70-84 years. We distributed an online survey via email to all general practices in Wales on their use of vaccination invitations and reminders, method of invitations, and characteristics of their vaccination delivery. We used linear regression to calculate coefficients and 95 %CI to measure associations between invitations and vaccine uptake, adjusting for key demographics, with a multi-level component to account for similarities between general practices within the same health board. Survey response rate was 37 % (143/384). Median vaccine uptake for responding general practices was 57 % (IQR 50-68 %) compared to 58 % (IQR 48-68 %) nationally. General practices inviting all eligible patients (n = 95) had a 9 % (95 %CI 6-13 %) higher vaccination uptake compared to those inviting none or some (n = 48, p < 0.001). Of practices sending invitations, those who reminded all patients (n = 42) had a 6 % (95 %CI 1-11 %, p = 0.02) higher uptake compared to those that reminded none (n = 30). Practice size was associated with higher uptake, with small practices (n = 11, p = 0.02) having coverage 9 % (95 %CI 2-16 %) higher compared to the reference population (medium-sized practices, n = 78). General practices inviting and reminding all eligible patients for shingles vaccination have a higher uptake compared to those inviting and reminding only some or none. From September 2023, shingles vaccination policy in Wales has been updated to explicitly mandate effective universal call and recall mechanisms in general practices.


Herpes Zoster Vaccine , Herpes Zoster , Vaccines , Humans , Aged , Cross-Sectional Studies , Wales , Herpes Zoster/prevention & control , Herpes Zoster/epidemiology , Herpesvirus 3, Human , Vaccination
19.
Echo Res Pract ; 11(1): 4, 2024 Feb 14.
Article En | MEDLINE | ID: mdl-38351041

BACKGROUND: The athlete's heart (AH) defines the phenotypical changes that occur in response to chronic exercise training. Echocardiographic assessment of the AH is used to calculate LV mass (LVM) and determine chamber geometry. This is, however, interpreted using standard linear (ratiometric) scaling to body surface area (BSA) whereas allometric scaling is now widely recommended. This study (1) determined whether ratiometric scaling of LVM to BSA (LVMiratio) provides a size-independent index in young and veteran athletes of mixed and endurance sports (MES), and (2) calculated size-independent beta exponents for allometrically derived (LVMiallo) to BSA and (3) describes the physiological range of LVMiallo and the classifications of LV geometry. METHODS: 1373 MES athletes consisting of young (< 35 years old) (males n = 699 and females n = 127) and veteran (> 35 years old) (males n = 327 and females n = 220) were included in the study. LVMiratio was calculated as per standard scaling and sex-specific LVMiallo were derived from the population. Cut-offs were defined and geometry was classified according to the new exponents and relative wall thickness. RESULTS: LVMiratio did not produce a size independent index. When tested across the age range the following indexes LVMi/BSA0.7663 and LVMi/BSA0.52, for males and females respectively, were size independent (r = 0.012; P = 0.7 and r = 0.003; P = 0.920). Physiological cut-offs for LVMiallo were 135 g/(m2)0.7663 in male athletes and 121 g/(m2)0.52 in female athletes. Concentric remodelling / hypertrophy was present in 3% and 0% of young male and female athletes and 24% and 17% of veteran male and female athletes, respectively. Eccentric hypertrophy was observed in 8% and 6% of young male and female athletes and 9% and 11% of veteran male and female athletes, respectively. CONCLUSION: In a large cohort of young and veteran male and female MES athletes, LVMiratio to BSA is not size independent. Sex-specific LVMiallo to BSA with LVMi/BSA0.77 and LVMi/BSA0.52 for male and female athletes respectively can be applied across the age-range. Population-based cut-offs of LVMiallo provided a physiological range demonstrating a predominance for normal geometry in all athlete groups with a greater percentage of concentric remodelling/hypertrophy occurring in veteran male and female athletes.

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