A mathematical model for wound healing in the reef-building coral Pocillopora damicornis.

Coral reefs, among the most diverse ecosystems on Earth, currently face major threats from pollution, unsustainable fishing practices , and perturbations in environmental parameters brought on by climate change. Corals also sustain regular wounding from other sea life and human activity. Recent reef restoration practices have even involved intentional wounding by systematically breaking coral fragments and relocating them to revitalize damaged reefs, a practice known as microfragmentation. Despite its importance, very little research has explored the inner mechanisms of wound healing in corals. Some reef-building corals have been observed to initiate an immunological response to wounding similar to that observed in mammalian species. Utilizing prior models of wound healing in mammalian species as the mathematical basis, we formulated a mechanistic model of wound healing, including observations of the immune response and tissue repair in scleractinian corals for the species Pocillopora damicornis. The model consists of four differential equations which track changes in remaining wound debris, number of cells involved in inflammation, number of cells involved in proliferation, and amount of wound closure through re-epithelialization. The model is fit to experimental wound size data from linear and circular shaped wounds on a live coral fragment. Mathematical methods, including numerical simulations and local sensitivity analysis, were used to analyze the resulting model. The parameter space was also explored to investigate drivers of other possible wound outcomes. This model serves as a first step in generating mathematical models for wound healing in corals that will not only aid in the understanding of wound healing as a whole, but also help optimize reef restoration practices and predict recovery behavior after major wounding events.

Use of a fluoroscopy-based robotic-assisted total hip arthroplasty system produced greater improvements in patient-reported outcomes at one year compared to manual, fluoroscopic-assisted technique.

INTRODUCTION: The adoption of new technology should be supported by improvements in patient-reported outcomes (PROMs). The purpose of this study was to assess the one-year PROMs of patients who underwent total hip arthroplasty (THA) using a novel, fluoroscopy-based, robotic-assisted (RA-THA) system when compared to a manual, fluoroscopic-assisted technique (mTHA). MATERIALS AND METHODS: A review of 91 consecutive mTHA and 85 consecutive RA-THA via a direct anterior approach was conducted. All cases were performed by the same surgeon at the same institution, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Outcomes included one-year Veterans RAND-12 (VR-12) Physical/Mental, Hip Disability and Osteoarthritis Outcome (HOOS) Pain/Physical Function/Joint Replacement, and University of California Los Angeles (UCLA) Activity scores, as well as the difference between pre-operative and one-year post-operative PROMs. RESULTS: Patients in the RA-THA cohort had lower pre-operative HOOS-JR scores compared to patients in the mTHA cohort (37.0 vs. 43.1; p = 0.031). Cohorts experienced similar one-year post-operative VR-12, HOOS, and UCLA Activity scores. Patients in the RA-THA cohort experienced greater improvements across all pre- and post-operative HOOS scores compared to patients in the mTHA cohort: Pain (+ 54.7 vs. +42.1; p = 0.009), Physical Function (-41.6 vs. -28.7; p = 0.007), and Joint Replacement (+ 46.6 vs. +33.0; p = 0.002). These differences exceeded minimum clinically important difference (MCID). CONCLUSIONS: Both manual and robotic cohorts experienced benefit from THA at one-year post-operative. Importantly, the use of a novel, fluoroscopy-based robotic assistance system for primary THA resulted in greater improvements in PROMs at one-year relative to manual technique.

What are the Outcomes After Primary Total Hip and Knee Arthroplasty in Patients With Prior Cerebrovascular Accidents?

BACKGROUND: For patients who have a history of cerebrovascular accident (CVA) with neurological sequelae undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA), we sought to determine mortality rate, implant survivorship, complications, and clinical outcomes. METHODS: Our total joint registry identified CVA sequelae patients undergoing primary THA (n = 42 with 25 on affected hip) and TKA (n = 56 with 34 on affected knee). Patients were 1:2 matched based upon age, sex, body mass index, and surgical year to a non-CVA cohort. Mortality and implant survivorship were evaluated via Kaplan-Meier methods. Clinical outcomes were assessed via Harris Hip scores or Knee Society scores . Mean follow-up was 5 years (range, 2-12). RESULTS: For CVA sequelae and non-CVA patients, respectively, the 5-year patient survivorship was 69 versus 89% after THA (HR = 2.5; P = .006) and 56 versus 90% after TKA (HR = 2.4, P = .003). No significant difference was noted between groups in implant survivorship free from any reoperation after THA (P > .2) and TKA (P > .6). Postoperative CVA occurred at an equal rate in CVA sequelae and non-CVA patients after TKA (1.8%); none after THA in either group. The magnitude of change in Harris Hip scores (P = .7) and Knee Society scores (P = .7) were similar for CVA sequelae and non-CVA patients. CONCLUSION: Complications, including the risk of postoperative CVA, implant survivorship, and outcome score improvement are similar for CVA sequelae and non-CVA patients. A 2.5-fold increased risk of death at a mean of 5 years after primary THA or TKA exist for CVA sequelae patients.

Piecing together the data of the U.S. marine aquaculture puzzle.

Aquaculture recently became the main source of global seafood production and many countries, including the United States, see potential in marine aquaculture to sustainably fill growing demand. The U.S. supports the majority of its seafood consumption through imports, and therefore identifying bottlenecks to domestic aquaculture growth is a priority at the federal and state level. Yet, one critical aspect that appears not yet addressed is the quality and accessibility of marine aquaculture data. In this study we conducted the first multi-state synthesis and comparison of the most comprehensive suite of species, volume, and value information on U.S. marine aquaculture over time, across the 23 marine coastal states. Using publicly available data sources from the U.S. Department of Agriculture (USDA), state-level solicited data that we aggregated, and data from the National Oceanic and Atmospheric Administration (NOAA), we found strong evidence that marine aquaculture has played an increasingly important role in marine coastal states, but also uncovered numerous data gaps and discrepancies between and within these sources. In particular, we found a dearth of volumetric data and millions in missing value (USD$). We found U.S. marine aquaculture is likely much more diverse, abundant and valuable than is currently reported, but the main sources of error in any given state remain unclear. We recommend U.S. state governments adopt a standardized, digital and annual data collection program, such as the NOAA Fisheries Information Networks. Better strategic aquaculture planning, management, and research depend on accurate data, and existing digital data infrastructures provide strong opportunities for improvement.

Skeletal muscle and cardiac transcriptomics of a regionally endothermic fish, the Pacific bluefin tuna, Thunnus orientalis.

BACKGROUND: The Pacific bluefin tuna (Thunnus orientalis) is a regionally endothermic fish that maintains temperatures in their swimming musculature, eyes, brain and viscera above that of the ambient water. Within their skeletal muscle, a thermal gradient exists, with deep muscles, close to the backbone, operating at elevated temperatures compared to superficial muscles near the skin. Their heart, by contrast, operates at ambient temperature, which in bluefin tunas can range widely. Cardiac function in tunas reduces in cold waters, yet the heart must continue to supply blood for metabolically demanding endothermic tissues. Physiological studies indicate Pacific bluefin tuna have an elevated cardiac capacity and increased cold-tolerance compared to warm-water tuna species, primarily enabled by increased capacity for sarcoplasmic reticulum calcium cycling within the cardiac muscles. RESULTS: Here, we compare tissue-specific gene-expression profiles of different cardiac and skeletal muscle tissues in Pacific bluefin tuna. There was little difference in the overall expression of calcium-cycling and cardiac contraction pathways between atrium and ventricle. However, expression of a key sarcoplasmic reticulum calcium-cycling gene, SERCA2b, which plays a key role maintaining intracellular calcium stores, was higher in atrium than ventricle. Expression of genes involved in aerobic metabolism and cardiac contraction were higher in the ventricle than atrium. The two morphologically distinct tissues that derive the ventricle, spongy and compact myocardium, had near-identical levels of gene expression. More genes had higher expression in the cool, superficial muscle than in the warm, deep muscle in both the aerobic red muscle (slow-twitch) and anaerobic white muscle (fast-twitch), suggesting thermal compensation. CONCLUSIONS: We find evidence of widespread transcriptomic differences between the Pacific tuna ventricle and atrium, with potentially higher rates of calcium cycling in the atrium associated with the higher expression of SERCA2b compared to the ventricle. We find no evidence that genes associated with thermogenesis are upregulated in the deep, warm muscle compared to superficial, cool muscle. Heat generation may be enabled by by the high aerobic capacity of bluefin tuna red muscle.

Phylotranscriptomic Insights into the Diversification of Endothermic Thunnus Tunas.

Birds, mammals, and certain fishes, including tunas, opahs and lamnid sharks, are endothermic, conserving internally generated, metabolic heat to maintain body or tissue temperatures above that of the environment. Bluefin tunas are commercially important fishes worldwide, and some populations are threatened. They are renowned for their endothermy, maintaining elevated temperatures of the oxidative locomotor muscle, viscera, brain and eyes, and occupying cold, productive high-latitude waters. Less cold-tolerant tunas, such as yellowfin tuna, by contrast, remain in warm-temperate to tropical waters year-round, reproducing more rapidly than most temperate bluefin tuna populations, providing resiliency in the face of large-scale industrial fisheries. Despite the importance of these traits to not only fisheries but also habitat utilization and responses to climate change, little is known of the genetic processes underlying the diversification of tunas. In collecting and analyzing sequence data across 29,556 genes, we found that parallel selection on standing genetic variation is associated with the evolution of endothermy in bluefin tunas. This includes two shared substitutions in genes encoding glycerol-3 phosphate dehydrogenase, an enzyme that contributes to thermogenesis in bumblebees and mammals, as well as four genes involved in the Krebs cycle, oxidative phosphorylation, ß-oxidation, and superoxide removal. Using phylogenetic techniques, we further illustrate that the eight Thunnus species are genetically distinct, but found evidence of mitochondrial genome introgression across two species. Phylogeny-based metrics highlight conservation needs for some of these species.

Cardiac remodeling in response to embryonic crude oil exposure involves unconventional NKX family members and innate immunity genes.

Cardiac remodeling results from both physiological and pathological stimuli. Compared with mammalian hearts, fish hearts show a broader array of remodeling changes in response to environmental influences, providing exceptional models for dissecting the molecular and cellular bases of cardiac remodeling. We recently characterized a form of pathological remodeling in juvenile pink salmon (Oncorhynchus gorbuscha) in response to crude oil exposure during embryonic cardiogenesis. In the absence of overt pathology (cardiomyocyte death or inflammatory infiltrate), cardiac ventricles in exposed fish showed altered shape, reduced thickness of compact myocardium and hypertrophic changes in spongy, trabeculated myocardium. Here, we used RNA sequencing to characterize molecular pathways underlying these defects. In juvenile ventricular cardiomyocytes, antecedent embryonic oil exposure led to dose-dependent upregulation of genes involved in innate immunity and two NKX homeobox transcription factors not previously associated with cardiomyocytes, nkx2.3 and nkx3.3 Absent from mammalian genomes, the latter is largely uncharacterized. In zebrafish embryos, nkx3.3 demonstrated a potent effect on cardiac morphogenesis, equivalent to that of nkx2.5, the primary transcription factor associated with ventricular cardiomyocyte identity. The role of nkx3.3 in heart growth is potentially linked to the unique regenerative capacity of fish and amphibians. Moreover, these findings support a cardiomyocyte-intrinsic role for innate immune response genes in pathological hypertrophy. This study demonstrates how an expanding mechanistic understanding of environmental pollution impacts - i.e. the chemical perturbation of biological systems - can ultimately yield new insights into fundamental biological processes.

Temperature dependent pre- and postprandial activity in Pacific bluefin tuna (Thunnus orientalis).

Bluefin tunas are highly specialized fish with unique hydrodynamic designs and physiological traits. In this study, we present results in a captive population that demonstrate strong effects of ambient temperature on the tail beat frequency and swimming speed of a pelagic fish in both pre- and post-prandial states. We measured the responses of a ram ventilator, the Pacific bluefin tuna (Thunnus orientalis), after digestion of a meal to explore the impacts of the metabolic costs of digestion on behavior and respiration. A combination of respirometry, physiological biologging of visceral temperatures, and activity monitoring with accelerometry were used to explore the metabolic costs of digestion and the impacts on ventilation and swimming speed. Experiments were conducted at temperatures that are within the metabolic optimum for Pacific bluefin tuna (17 °C), and at a second temperature corresponding to the upper distributional limit of the species in the California Current (24 °C). Warmer temperatures resulted in higher tail-beat frequency and greater elevation of body temperature in pre-prandial Pacific bluefin tuna. Specific dynamic action (SDA) events resulted in a significant postprandial increase in tail-beat frequency of ~0.2 Hz, compared to pre-prandial levels of 1.5 Hz (17 °C) and 1.75 Hz (24 °C), possibly resulting from ventilatory requirements. Data of fish exercised in a swim-tunnel respirometer suggest that the observed increase in tail-beat frequency comprise 5.5 and 6.8% of the oxygen demand during peak SDA at 24 °C and 17 °C respectively. The facultative increase in swimming speed might increase oxygen uptake at the gills to meet the increasing demand by visceral organs involved in the digestive process, potentially decreasing the available energy of each meal for other metabolic processes, such as growth, maturation, and reproduction. We hypothesize that these post-prandial behaviors allow tuna to evacuate their guts more quickly, ultimately permitting fish to feed more frequently when prey is available.

Assessing niche width of endothermic fish from genes to ecosystem.

Endothermy in vertebrates has been postulated to confer physiological and ecological advantages. In endothermic fish, niche expansion into cooler waters is correlated with specific physiological traits and is hypothesized to lead to greater foraging success and increased fitness. Using the seasonal co-occurrence of three tuna species in the eastern Pacific Ocean as a model system, we used cardiac gene expression data (as a proxy for thermal tolerance to low temperatures), archival tag data, and diet analyses to examine the vertical niche expansion hypothesis for endothermy in situ. Yellowfin, albacore, and Pacific bluefin tuna (PBFT) in the California Current system used more surface, mesopelagic, and deep waters, respectively. Expression of cardiac genes for calcium cycling increased in PBFT and coincided with broader vertical and thermal niche utilization. However, the PBFT diet was less diverse and focused on energy-rich forage fishes but did not show the greatest energy gains. Ecosystem-based management strategies for tunas should thus consider species-specific differences in physiology and foraging specialization.

Deepwater Horizon crude oil impacts the developing hearts of large predatory pelagic fish.

The Deepwater Horizon disaster released more than 636 million L of crude oil into the northern Gulf of Mexico. The spill oiled upper surface water spawning habitats for many commercially and ecologically important pelagic fish species. Consequently, the developing spawn (embryos and larvae) of tunas, swordfish, and other large predators were potentially exposed to crude oil-derived polycyclic aromatic hydrocarbons (PAHs). Fish embryos are generally very sensitive to PAH-induced cardiotoxicity, and adverse changes in heart physiology and morphology can cause both acute and delayed mortality. Cardiac function is particularly important for fast-swimming pelagic predators with high aerobic demand. Offspring for these species develop rapidly at relatively high temperatures, and their vulnerability to crude oil toxicity is unknown. We assessed the impacts of field-collected Deepwater Horizon (MC252) oil samples on embryos of three pelagic fish: bluefin tuna, yellowfin tuna, and an amberjack. We show that environmentally realistic exposures (1-15 µg/L total PAH) cause specific dose-dependent defects in cardiac function in all three species, with circulatory disruption culminating in pericardial edema and other secondary malformations. Each species displayed an irregular atrial arrhythmia following oil exposure, indicating a highly conserved response to oil toxicity. A considerable portion of Gulf water samples collected during the spill had PAH concentrations exceeding toxicity thresholds observed here, indicating the potential for losses of pelagic fish larvae. Vulnerability assessments in other ocean habitats, including the Arctic, should focus on the developing heart of resident fish species as an exceptionally sensitive and consistent indicator of crude oil impacts.

Ischiofemoral impingement and hamstring dysfunction as a potential pain generator after ischial tuberosity apophyseal fracture non-union/malunion.

PURPOSE: The purpose of this study was to describe the occurrence of ischiofemoral impingement (IFI) and hamstring dysfunction following malunion or non-union of ischial tuberosity apophyseal avulsion fractures and report the short-term outcomes of surgical treatment with regard to alleviating symptomatic extra-articular impingement. METHODS: All patients who underwent surgery for recalcitrant hip and buttock pain in the setting of prior ischial tuberosity avulsion fracture at three tertiary-level hip preservation centres were included for this review. A total of ten patients met our inclusion criteria and underwent sciatic neurolysis, resection of the ischial tuberosity fragment and hamstring reattachment. Clinical outcomes scores were collected post-operatively including the Modified Harris Hip Score (mHHS) and the Hip Outcomes Score (HOS). RESULTS: Ten patients with a mean age of 18 years (range 14-28) underwent surgery for symptomatic ischiofemoral impingement after ischial tuberosity avulsion fracture. At a mean of 2.2-year follow-up (range 1.7-3.5), the median post-operative mHHS was 89.7 (65.7-96.8) and HOS ADL and Sport subscales were 90 % or greater in all cases. Five patients (50 %) rated their hip as normal, and five patients (50 %) rated their hip as near normal. CONCLUSION: Malunion or non-union following ischial tuberosity apophyseal fracture can lead to IFI and hamstring dysfunction. Clinically, the resultant pain and dysfunction is often chronic, and can be debilitating. In select cases, a reliable surgical technique is presented to improve hamstring function and correct ischiofemoral impingement in this setting with good-to-excellent outcomes in the majority of cases at short-term follow-up. LEVEL OF EVIDENCE: IV.

Quantification of Environmental DNA (eDNA) Shedding and Decay Rates for Three Marine Fish.

Analysis of environmental DNA (eDNA) to identify macroorganisms and biodiversity has the potential to significantly augment spatial and temporal biological monitoring in aquatic ecosystems. Current monitoring methods relying on the physical identification of organisms can be time consuming, expensive, and invasive. Measuring eDNA shed from organisms provides detailed information on the presence and abundance of communities of organisms. However, little is known about eDNA shedding and decay in aquatic environments. In the present study, we designed novel Taqman qPCR assays for three ecologically and economically important marine fish-Engraulis mordax (Northern Anchovy), Sardinops sagax (Pacific Sardine), and Scomber japonicas (Pacific Chub Mackerel). We subsequently measured fish eDNA shedding and decay rates in seawater mesocosms. eDNA shedding rates ranged from 165 to 3368 pg of DNA per hour per gram of biomass. First-order decay rate constants ranged from 0.055 to 0.101 per hour. We also examined the size fractionation of eDNA and concluded eDNA is both intra- and extracellular. Finally, we derived a simple mass-balance model to estimate fish abundance from eDNA concentration. The mesocosm-derived shedding and decay rates inform the interpretation of eDNA concentrations measured in environmental samples and future use of eDNA as a monitoring tool.

The effect of temperature on postprandial metabolism of yellowfin tuna (Thunnus albacares).

Specific dynamic action (SDA), the increase in metabolic expenditure associated with consumption of a meal, represents a substantial portion of fish energy budgets and is highly influenced by ambient temperature. The effect of temperature on SDA has not been studied in yellowfin tuna (Thunnus albacares, Bonnaterre 1788), an active pelagic predator that occupies temperate and subtropical waters. The energetic cost and duration of SDA were calculated by comparing routine and post-prandial oxygen consumption rates. Mean routine metabolic rates in yellowfin tuna increased with temperature, from 136 mg O2 kg(-1)h(-1) at 20 °C to 211 mg O2 kg(-1)h at 24 °C. The mean duration of SDA decreased from 40.2h at 20 °C to 33.1h at 24 °C, while mean SDA coefficient, the percentage of energy in a meal that is consumed during digestion, increased from 5.9% at 20 °C to 12.7% at 24 °C. Digestion in yellowfin tuna is faster at a higher temperature but requires additional oxidative energy. Enhanced characterization of the role of temperature in SDA of yellowfin tuna deepens our understanding of tuna physiology and can help improve management of aquaculture and fisheries.

Does Prior Surgery for Femoroacetabular Impingement Compromise Hip Arthroplasty Outcomes?

BACKGROUND: Open and arthroscopic approaches have been described to address femoroacetabular impingement (FAI). Despite good outcomes, there is a subset of patients who subsequently require total hip arthroplasty (THA). However, there is a paucity of data on the outcomes of THA after surgery for FAI. The purpose of this study was to determine whether clinical outcomes of THA are affected by prior open or arthroscopic treatment of FAI. METHODS: This case-matched retrospective review included 23 patients (24 hips) that underwent THA after previous surgery for FAI (14 arthroscopic and 10 open) and compared them to 24 matched controls with no history of prior surgery on the operative hip. The controls were matched for age, sex, surgical approach, implants used, and preoperative modified Harris hip score (mHHS) did not differ between groups. The primary outcome measure was the mHHS. Operative time, blood loss, and the presence of heterotopic ossification after THA were also compared between groups. RESULTS: There was no significant difference in mean mHHS between the FAI treatment group 92.9 ± 12.7 and controls 95.2 ± 6.6 (P = .43) at a mean follow-up after THA of 33 (24-70) months. Increased operative times were noted for THA after surgical hip dislocation (SHD; mean 109.3 ± 29.8) compared to controls (mean 88.0 ± 24.2; P < .05). There was no significant difference in blood loss between groups. The occurrence of heterotopic ossification was significantly higher after SHD compared to controls (P < .05). CONCLUSIONS: Clinical outcomes after THA are not affected by prior open or arthroscopic procedures for FAI. However, increased operative times and an increased risk of heterotopic ossification were noted after SHD.

Resection Technique Does Affect Resection Symmetry and Thickness of the Patella During Total Knee Arthroplasty: A Prospective Randomized Trial.

The purpose of this study was to evaluate the accuracy and efficiency of three patellar resection techniques: cutting guide, free hand with haptic feedback, and a novel technique utilizing four quadrant measurements. Ninety patients undergoing TKA were randomized to receive patellar resurfacing by one of the three study techniques. The novel four quadrant technique resulted in least post-resection asymmetry (0.85 mm, P = 0.001). The most accurate methods for obtaining desired thickness were haptic feedback (0.66 mm mean discrepancy [MD]) and novel four quadrant technique (0.66 mm MD) followed by the patellar cutting guide (1.40 mm MD) (P < 0.001). Use of a patellar cutting guide resulted in increased patellar asymmetry and decreased accuracy in obtaining desired patellar thickness in this prospective trial.

A comprehensive five-phase rehabilitation programme after hip arthroscopy for femoroacetabular impingement.

PURPOSE: Recent advancements in the understanding of hip biomechanics have led to the development of techniques to remove bony impingement and repair and/or preserve the labrum during hip arthroscopy. Although much attention in the literature is devoted to diagnosis and treatment, there is little information about post-operative rehabilitation. Therefore, the purpose of this review is to (1) provide a five-phase rehabilitation protocol following arthroscopic treatment for FAI and (2) report clinical and functional outcomes of patients following this protocol at minimum 1-year follow-up, in order to provide the surgeon and therapist with a protocol that is supported by clinical data. METHODS: All consecutive patients undergoing hip arthroscopy and subsequent five-phase rehabilitation protocol at a single institution from 1 April 2011 to 1 April 2012 were analysed. Inclusion criteria were as follows: no prior ipsilateral hip surgery, completion of the five-phase rehabilitation protocol, minimum 1-year follow-up, and documented outcome scores. Prospective outcomes were assessed with modified Harris hip score (MHHS) and hip outcome score (HOS). RESULTS: Fifty-two patients (19 male and 33 female) met the inclusion criteria with a median age of 42 (range 16-59) years. Mean MHHS, HOS-ADL, and HOS-sport scores at a mean 12.5 (range 12-15) months were 80.1 ± 19.9 (0-100), 83.6 ± 19.2 (13.2-100), and 70.3 ± 27.0 (0-100), respectively. CONCLUSION: This five-phase rehabilitation programme provides a framework where progression from surgery to increasing post-operative activity level can take place in a predictable manner. Patients following this rehabilitation protocol after hip arthroscopy demonstrated satisfactory clinical and functional outcomes, validating its implementation.

Sagittal Pelvic Tilt Directly Influences the Ischiofemoral Space: A Cadaveric Study.

BACKGROUND: Ischiofemoral impingement (IFI) is understood to be a pain generator in the deep gluteal space. Femoral position is known to influence the ischiofemoral space (IFS), but there has been no study examining the effect of sagittal pelvic tilt on the IFS. The purpose of this study was to determine whether changes in pelvic tilt in the sagittal plane lead to changes in the dimensions of the IFS. MATERIALS AND METHODS: Five fresh frozen cadavers (10 hips) were used for this anatomic study. The specimens were skeletonized and placed in the prone position with the pelvis fixed to a custom-built hinged table. A digital inclinometer was used to tilt the pelvis -10°, 0°, and 10° simulating posterior, neutral, and anterior pelvic tilt, respectively. Digital calipers were used to measure the dimensions of the IFS in all three positions of sagittal pelvic tilt. RESULTS: Changes in pelvic tilt resulted in significant changes in the dimensions of the IFS. Mean IFS dimensions measured 29.3±9.7 mm, 37.2±9.0 mm, and 24.3±9.2 mm in the neutral, anterior, and posterior pelvic tilt positions, respectively (P<.0001). CONCLUSION: Changes in sagittal pelvic tilt influence the dimensions of the IFS, with posterior pelvic tilt noted to significantly decrease the IFS when compared with neutral and anterior pelvic tilt. These findings suggest that further evaluation of sagittal spinopelvic balance in the etiology of symptomatic IFI may be warranted. [Orthopedics. 2024;47(3):167-171.].

Do All Postoperative Vancouver B2 Fractures Require Revision Arthroplasty With Cementless Stems?

Background: Management of periprosthetic fractures has been guided by the Vancouver classification, which recommends revision for fractures around a loose femoral implant (B2). New studies have challenged this approach, demonstrating acceptable outcomes with internal fixation. This study evaluates our experience with Vancouver B2 fractures, comparing internal fixation to femoral revision. We hypothesized that in select cases with cementless stems, internal fixation would provide acceptable results with reduced morbidity. Methods: A retrospective review was performed of periprosthetic hip fractures treated at our institution between 1 January 2012 and 4 November 2022. We excluded patients who did not have prior radiographs and evidence of stem subsidence, suggestive of a Vancouver B2 fracture. Thirteen patients were included in the analysis. Results: Four patients (31%) underwent revision of the femoral component, 4 patients (31%) underwent plating, and 5 patients (38%) underwent internal fixation with cerclage cabling. The average operative duration was 158 minutes, 203 minutes, and 62 minutes for the revision, plating, and cabling cohorts, respectively (P = .009). Blood loss was 463 cc, 510 cc, and 90 cc for the revision, plating, and cabling cohorts, respectively (P = .036). Three patients in both the revision and plating cohorts each received a transfusion (75%), whereas no patients in the cabling cohort required a transfusion (P = .033). All patients demonstrated fracture healing on the postoperative radiographs. No patients required additional surgery during the follow-up period. Conclusions: We have demonstrated that Vancouver B2 periprosthetic fractures with intact lateral cortices may be treated with internal fixation with cerclage cabling with excellent results.

Effects of temperature acclimation on Pacific bluefin tuna (Thunnus orientalis) cardiac transcriptome.

Little is known about the mechanisms underpinning thermal plasticity of vertebrate hearts. Bluefin tuna hearts offer a unique model to investigate processes underlying thermal acclimation. Their hearts, while supporting an endothermic physiology, operate at ambient temperature, and are presented with a thermal challenge when migrating to different thermal regimes. Here, we examined the molecular responses in atrial and ventricular tissues of Pacific bluefin tuna acclimated to 14°C, 20°C, and 25°C. Quantitative PCR studies showed an increase in sarcoplasmic reticulum Ca(2+) ATPase gene expression with cold acclimation and an induction of Na(+)/Ca(2+)-exchanger gene at both cold and warm temperatures. These data provide evidence for thermal plasticity of excitation-contraction coupling gene expression in bluefin tunas and indicate an increased capacity for internal Ca(2+) storage in cardiac myocytes at 14°C. Transcriptomic analysis showed profound changes in cardiac tissues with acclimation. A principal component analysis revealed that temperature effect was greatest on gene expression in warm-acclimated atrium. Overall data showed an increase in cardiac energy metabolism at 14°C, potentially compensating for cold temperature to optimize bluefin tuna performance in colder oceans. In contrast, metabolic enzyme activity and gene expression data suggest a decrease in ATP production at 25°C. Expression of genes involved in protein turnover and molecular chaperones was also decreased at 25°C. Expression of genes involved in oxidative stress response and programmed cell death suggest an increase in oxidative damage and apoptosis at 25°C, particularly in the atrium. These findings provide insights into molecular processes that may characterize cardiac phenotypes at upper thermal limits of teleosts.