Discover and publish cutting edge, open research.

Browse 23,744 multi-disciplinary research preprints

Most recent

Background and Purpose: Dysregulation of adult hippocampal neurogenesis is linked to major depressive disorder (MDD), with more than 300 million people diagnosed and worsened by the COVID-19 pandemic. Accumulating evidence for Neuropeptide Y (NPY) and galanin (GAL) interaction was shown in various limbic system regions at molecular-,cellular- and behavioral-specific levels. The purpose of the current work was to evaluate the proliferating role of GALR2 and Y1R agonists interaction upon intranasal infusion in the ventral hippocampus. Experimental approach: We studied their hippocampal proliferating actions using the proliferating cell nuclear antigen (PCNA) and the expression of of the brain-derived neurothrophic factor (BDNF). Moreover, we studied the formation of Y1R-GALR2 heteroreceptor complexes and analyzed morphological changes on hippocampal neuronal cells. Finally, the functional outcome of the NPY and GAL interaction on the ventral hippocampus was evaluated in the forced swimming test. Key Results: We demonstrated that the intranasal infusion of GALR2 and the Y1R agonists promotes cell proliferation in the DG of the ventral hippocampus and the induction of the neurotrophic factor BDNF. These effects were mediated by the increased formation of Y1R-GALR2 heteroreceptor complexes, which may mediate the neurites outgrowth observed on neuronal hippocampal cells. Importantly, BDNF action was found necessary for the antidepressant-like effects after GALR2 and the Y1R agonists intranasal administration. Conclusions & Implications: Our data may suggest the translational development of new heterobivalent agonist pharmacophores acting on Y1R–GALR2 heterocomplexes in the ventral hippocampus for the novel therapy of mayor depression disorder or depressive-affecting diseases.

Xiaoqi Wang

and 6 more

Carex heterostachya (CH) and Carex breviculmis (CB) are easy to develop lawns in a short period and exhibit high ornamental value in northwest China. So, what type of plant functional traits has they formed for long-term survival and adaptation to this environment, which plant is more adaptable, as well as which leaf functional traits are critical to photosynthetic characteristics. The result of this study suggests that (1) CB is a slow investment-return plant with strong environmental adaptability and plasticity in long-term shaded environments. It is characterized by its weak photosynthetic capacity, smaller specific leaf area, low CO2 compensation point, high water utilization rate, high maximum carboxylation rate, as well as dark breathing rate. Moreover, it also has a thick cuticle, and epidermal cells make CB resistant to drought and barrenness. (2) CH is a quick investment-return plant, which is characterized by its higher photosynthetic rate, transpiration rate, stomatal conductance, as well as larger specific leaf area. With the increase of the temperature and photosynthetically active radiation, CH maintains high photosynthetic capacity by decreasing the transpiration rate and increasing the utilization rate of light energy. Its conducting tissue is well developed. CH have lower light saturation points and light compensation points, and CH was more shade-tolerant than CB. (3) Carex have strong environmental adaptability, large variation in leaf structure traits, as well as strong plasticity. Leaf anatomical characters are stable, whereas there are differences in the interspecific variability and plasticity. (4) Specific leaf area (SLA) can serve as the main factor affecting the photosynthetic availability of Carex, the thickness of the stratum corneum(CUT), the thickness of the upper(UET) are secondary factors. These finding can provide a theoretical basis for the cultivation and application of Carex and the expansion of turfgrass germplasm resources.
As global warming progresses, plants may be forced to adapt to drastically changing environmental conditions. Arctic-alpine plants have been among the first to experience the effects of climate change, as regions at high latitudes and elevations are over-proportionally affected by rising temperatures. As a result, cold acclimation and freezing tolerance may become increasingly crucial for the survival of many plants as winter warming events and earlier snowmelt will cause increased exposure to occasional frost. Studying the evolution of cold adaptation allows us to make assumptions about the future responses of different species to climate change. The tribe Cochlearieae from the mustard family (Brassicaceae) offers an instructive system for studying cold adaptation in evolutionary terms, as the two sister genera Ionopsidium and Cochlearia are distributed among different ecological habitats throughout the European continent and the far north into circumarctic regions. By applying an electrolyte leakage assay to leaves, the freezing tolerance of different Ionopsidium and Cochlearia species was assessed by experimentally estimating lethal freezing temperature values (LT50 and LT100), thereby allowing for a comparison of different accessions in their responses to cold. We hypothesized that, owing to varying selection pressures, geographically distant species would differ in freezing tolerance. Despite Ionopsidium being adapted to hot and dry Mediterranean conditions and Cochlearia species preferring cold habitats, all accessions exhibited similar cold responses. Whether this phenomenon has resulted from an evolutionary adaptation of a common ancestor of the two taxa or has evolved from parallel evolution is yet to be investigated. The results presented in this study may, however, indicate that adaptations to different stressors, such as salinity and drought, may confer an additional tolerance to cold; this is because all these stressors induce osmotic challenges, as demonstrated via metabolomic analysis.

Marion Cordonnier

and 4 more

The domestic cat, Felis catus, is one of the most popular and widespread domestic animals. Because domestic cats can reach high population densities and retain at least some tendency to hunt, their overall impact on wildlife can be severe. Domestic cats have highly variable predation rates depending on the availability of prey in their environment, their owners' practices, and individual cat characteristics. Among these characteristics, cat personality has recently been hypothesized to be an important factor contributing to variations in the hunting activity of cats. In this study, we used surveys of 2,508 cat owners living in France to collect information about cat personalities using the Feline Five personality model and about the frequency with which the cats bring home prey. For both birds and rodents, cats with high levels of extraversion or low levels of neuroticism had significantly higher frequencies of prey return. Owners whose cats had low levels of agreeableness or high levels dominance reported a significantly lower frequency of bird return. Personality differences therefore seem to contribute to the high variability in predation rates between domestic cats. We also found that the owner-reported prey return frequencies were significantly higher for cats spending more time outdoors, for non-pedigree cats, and for owners living in rural or suburban areas as opposed to urban areas. By contrast, we did not detect an effect of cat sex or age on their reported prey return rates.

Cai Xiaotong

and 8 more

Background: Hypertensive disorder of pregnancy (HDP), a common obstetric complication that seriously threatens maternal and infant health. The current clinical treatment drugs include methyldopa, calcium channel blockers, etc. In order to provide evidence-based medicine for the treatment and medication of gestational hypertension, this study compared the efficacy and safety of different drugs in the treatment of gestational hypertension through network meta-analysis. Methods: Search and select relevant articles in the published and unpublished available data from Controlled Trials, PsycINFO, CINAHL,, etc. To assess the efficacy and safety of HDP treatment, 4 primary outcomes [SBP, DBP, perinatal fetal deaths, and NICU cases] and 9 secondary outcomes were selected. Results: 50 articles with 8212 participants were included. Low molecular weight heparin (LMH), Labetalol + LMH and Labetalol + Methyldopa can reduce DBP, and Ambrisentan + Methyldopa can prevent the occurrence of severe hypertension. Methyldopa and Atenolol were associated with lower rates of preterm birth, and Nifedipine, Methyldopa as well as Labetalol reduced the incidence of placental abruption. Ambrisentan + Nifedipine, Methyldopa, Labetalol + Nimodipine, Labetalol + LMH, Labetalol and LMH significantly reduced the incidence of postpartum complications. Magnesium sulfate (SM) and SM+ LMH can prolong the mean gestational age, LMH and Kethyldopa can reduce perinatal fetal death. Conclusions: LMH, labetalol, Methyldopa, labetalol in combination with LMH, and labetalol in combination with Methyldopa have better efficacy and safety.

Browse more recent preprints

Recently published in scholarly journals

Omar Sharaf

and 4 more

Background: Dysphagia following cardiac surgery is common and associated with adverse outcomes. Among patients receiving left ventricular assist device (LVAD), we evaluated the impact of fiberoptic endoscopic evaluation of swallowing (FEES) on outcomes. Methods: A single-center pilot study was conducted in adults (≥18 years of age) undergoing durable LVAD (February 2019-January 2020). Six patients were prospectively enrolled, evaluated, and underwent FEES within 72 hours of extubation—they were compared to 12 control patients. Demographic, surgical, and postoperative outcomes were collected. Unpaired two-sided t-tests and Fisher’s Exact tests were performed. Results: Baseline characteristics were similar between groups. Intraoperative criteria including duration of transesophageal echo (314 ± 86 min) and surgery (301 ± 74 min) did not differ. Mean time of intubation was comparable (57.3 vs. 68.7 hours, p=0.77). In the entire cohort, 30-day, 1-year, 2-year, and 3-year mortality were 0%, 5.6%, 5.6%, and 16.7%, respectively. Sixty-seven percent of the patients that underwent FEES had inefficient swallowing function. The FEES group trended to a shorter hospital length of stay (LOS) (29.1 vs. 46.6 days, p=0.098), post-implantation LOS (25.3 vs 30.7 days, p=0.46), and lower incidence of postoperative pneumonia (16.7% vs. 50%, p=0.32) and sepsis (0% vs. 33.3%, p=0.25). Conclusions: FEES did not impact 30-day, 1-year, 2-year, or 3-year mortality. Patients who underwent FEES trended toward shorter LOS, and lower postoperative pneumonia and sepsis rates, though not statistically significant. A higher incidence of dysphagia among patients undergoing FEES despite comparable baseline risk factors with controls suggests FEES may detect subclinical dysphagia.

Joshua Sink

and 1 more

Employing New Criteria for Confirmation of Conduction Pacing – Achieving True Left Bundle Branch Pacing May Be Harder Than Meets the EyeJoshua Sink, MD1, Nishant Verma, MD, MPH2Northwestern University, Feinberg School of Medicine, Department of Internal MedicineNorthwestern University, Feinberg School of Medicine, Division of CardiologyCorresponding Author:Nishant Verma, MD, MPH251 East Huron Street, Feinberg 8-503Chicago, IL 60611312-926-2148Nishant.Verma@nm.orgFunding: NoneDisclosures: Dr. Sink has nothing to disclose. Dr. Verma receives speaker honoraria from Medtronic, Biotronik and Baylis Medical and consulting fees from Boston Scientific, Biosense Webster, AltaThera Pharmaceuticals and Knowledge 2 Practice.Word Count: 1200In recent years, conduction system pacing (CSP) has garnered significant attention from the electrophysiology (EP) community. This movement has been driven by the hypothesis that using the natural conduction system activation is desirable and clinically beneficial in patients with advanced conduction disease and ventricular desynchrony. Permanent His-bundle pacing (PHBP) is generally seen as the purest form of conduction system activation. (Figure 1) PHBP was first described over 20 years ago but the idea has attracted substantial investigative effort in recent years. When successfully achieved, His bundle pacing has been associated with reduction in mortality, reduction in heart failure (HF) admissions, and improvement in left ventricular (LV) function compared to right ventricular (RV) pacing.1 Despite this, consistent achievability in real-world practice remains limited due to a variety of factors including narrow anatomic targetability, lead stability, high pacing thresholds, low ventricular sensing, and inability to correct the QRS in bundle branch block.2Thus, while waiting for the next iteration of improved delivery techniques, pacing leads and programming algorithms,, alternative methods of conductive system pacing have emerged, with the potential to surmount the challenges described.Left bundle branch pacing (LBBP) has recently emerged as an alternative method of CSP. The technique was first described by Huang et al. in 2017 and has seen a momentous rise in interest since.3 In 2019, Huang et al. produced a user manual for a successful LBBP procedure, and in it they attempted to develop the first iteration of criteria for the confirmation of LBBP.4 Utilizing these criteria, or close variations of them, a number of studies were published afterwards that demonstrated preliminary safety, feasibility, and efficacy of LBBP.5,6,7 LBBP became an attractive alternative to His bundle pacing because of the lower thresholds, improved lead stability, and higher procedural success rates. When compared against RV pacing in patients requiring a high burden of pacing, LBBP has demonstrated reduced mortality, HF admissions, and need for upgrade to a BiV device.8 In a small, non-randomized patient sample, LBBP showed greater improvement in LV ejection fraction (EF) compared to BiV pacing.9 Most notably, perhaps, is the astonishing rate of lead placement success, with achievement rates reported as high as 98% in sizable studies.6Differences between the two forms of CSP were apparent from the beginning, including in the appropriate QRS morphology after a successful case. Unlike PHBP, LBBP did not reproduce the native QRS and the QRS duration was often greater than at baseline (Figure 2). The arena of LBBP underwent a notable shift in the Fall of 2021 when Wu et al. proposed new criteria to prove LBBP.10 In this study, they presented an exquisite display of fundamental electrophysiologic principles by using mapping catheters positioned on the His and LV septum during LBB lead placement. Through this painstaking work, they clarified the difference between true LBBP and left bundle branch area pacing (LBBAP), which can incorporate both LBBP and left ventricular septal pacing (LVSP). In their proposed framework, without the presence of a His or LV septum mapping catheter, output dependent QRS transition from non-selective (NS-LBBP) to selective-LBBP (S-LBBP) or LVSP is necessary to prove LBBP and had a sensitivity and specificity of 100%.The present study by Shimeno et al, published in the current issue of the Journal of Cardiovascular Electrophysiology , is the first known effort to document achievement rates of LBBP by utilizing the modified criteria proposed by Wu et al.11 The primary finding of the study is that achieving true LBBP with an acceptable pacing threshold is likely harder than previously realized. As expected, there was improvement after a learning curve, but even in the last third of patients enrolled, the achievement rate of LBBP was only 50%. This is dramatically lower than previously reported achievement rates using the original Huang et al. criteria, and it suggests that not all patients in the previously described studies were actually achieving true LBBP. An unknown subset of patients in these studies was likely only achieving LVSP. This is probably due to a prior reliance on indicators such as a paced right bundle branch block (RBBB) pattern, identification of an intrinsic LBB potential, and/or use of V6 R-wave peak time cutoffs (RWPT) without clear output-dependent QRS transition. It is also worth noting that a variety of RWPT cutoffs have been used seemingly arbitrarily as ‘evidence of LBBP’. This presents a major dilemma and highlights the need for a clear set of LBBP criteria to be defined by the collective EP community. Despite these caveats, many of these previous studies did not fully confirm LBBP in their patients, yet the outcomes from these studies were still clinically promising. This raises the obvious question, does obtaining true LBBP matter? Future studies will need to explore the differences in clinical outcomes between true LBBP and LVSP.Secondarily, Shimeno et al. have provided a useful tool in identifying that LBB potential to QRS-onset ≥ 22ms had a specificity of 98% in predicting LBBP.11 This target measure can help future operators ensure proximal enough engagement of the LBB conduction system. Additionally, the group took a close look at validating a RWPT cutoff time for the prediction of LBBP. Unfortunately, a RWPT cutoff of 68 ms (in non-LBBB patients), determined by the ROC curve, was not highly predictive. This runs contrary to previous reports by Wu et al. and Jastrzebski et al., which reported higher predictive value of RWPT cutoffs10,12 Looking at the data surrounding RWPT cutoffs as a collective, it likely should not be used as a primary metric for confirming LBBP due to imperfect sensitivity and specificity, but it may be an alternative if output dependent QRS transition or change in RWPT of ≥10 ms is not observed. Additionally, in the event that capture thresholds are similar between the LBB and the adjacent myocardium, programmed stimulation is an option to try to reveal a QRS transition by exploiting differences in refractory periods.This study also highlighted one of the unique complications of LBBP by demonstrating a high rate of septal perforation. Paradoxically, more perforations were seen with increased experience, likely highlighting that deeper penetration into the septum is often sought as operators become more familiar with the procedure. The long-term clinical implications of this complication are, thus far, unknown.Looking forward, clear guidelines for confirmation of LBBP need to be defined. This is necessary to ensure quality before undertaking multi-center randomized controlled trials to assess LBBP in comparison to current pacing methods. To date, Wu et al. seem to have provided the best framework to achieve this.10 That said, there are concerns given that this has only been validated in 30 patients (and only 9 with LBBB). In an ideal world, these criteria would be validated in a larger population, though the work to accomplish this would be meticulous given the current gold standard of using an LV septal mapping catheter to prove conduction system capture. Shimeno et al. should be congratulated for their effort in putting this framework to practice. In their work, they have demonstrated that achieving true LBBP as defined by Wu et al. may be harder than meets the eye, and this is very important in assessing the practicality of using LBBP as a widespread alternative to other pacing methods.References:Abdelrahman M, Subzposh FA, Beer D, et al. Clinical Outcomes of His Bundle Pacing Compared to Right Ventricular Pacing. J Am Coll Cardiol . 2018;71(20):2319-2330. doi:10.1016/j.jacc.2018.02.048Zanon F, Abdelrahman M, Marcantoni L, et al. Long term performance and safety of His bundle pacing: A multicenter experience. J Cardiovasc Electrophysiol . 2019;30(9):1594-1601. doi:10.1111/jce.14063Huang W, Su L, Wu S, et al. A Novel Pacing Strategy With Low and Stable Output: Pacing the Left Bundle Branch Immediately Beyond the Conduction Block. Can J Cardiol . 2017;33(12):1736.e1-1736.e3. doi:10.1016/j.cjca.2017.09.013Huang W, Chen X, Su L, Wu S, Xia X, Vijayaraman P. A beginner’s guide to permanent left bundle branch pacing. Heart Rhythm . 2019;16(12):1791-1796. doi:10.1016/j.hrthm.2019.06.016Padala SK, Master VM, Terricabras M, et al. Initial Experience, Safety, and Feasibility of Left Bundle Branch Area Pacing: A Multicenter Prospective Study. JACC Clin Electrophysiol . 2020;6(14):1773-1782. doi:10.1016/j.jacep.2020.07.004Su L, Wang S, Wu S, et al. Long-Term Safety and Feasibility of Left Bundle Branch Pacing in a Large Single-Center Study. Circ Arrhythm Electrophysiol . 2021;14(2):e009261. doi:10.1161/CIRCEP.120.009261Huang W, Wu S, Vijayaraman P, et al. Cardiac Resynchronization Therapy in Patients With Nonischemic Cardiomyopathy Using Left Bundle Branch Pacing. JACC Clin Electrophysiol . 2020;6(7):849-858. doi:10.1016/j.jacep.2020.04.011Sharma PS, Patel NR, Ravi V, et al. Clinical outcomes of left bundle branch area pacing compared to right ventricular pacing: Results from the Geisinger-Rush Conduction System Pacing Registry. Heart Rhythm . 2022;19(1):3-11. doi:10.1016/j.hrthm.2021.08.033Wu S, Su L, Vijayaraman P, et al. Left Bundle Branch Pacing for Cardiac Resynchronization Therapy: Nonrandomized On-Treatment Comparison With His Bundle Pacing and Biventricular Pacing. Can J Cardiol . 2021;37(2):319-328. doi:10.1016/j.cjca.2020.04.037Wu S, Chen X, Wang S, et al. Evaluation of the Criteria to Distinguish Left Bundle Branch Pacing From Left Ventricular Septal Pacing. JACC Clin Electrophysiol . 2021;7(9):1166-1177. doi:10.1016/j.jacep.2021.02.018Shimeno K, Tamura S, Hayashi Y, et al. Achievement Rate and Learning Curve of Left Bundle Branch Capture in Left Bundle Branch Area Pacing Procedure Performed to Demonstrate Output-Dependent QRS Transition.J Cardiovasc Electrophysiol . 2022Jastrzębski M, Kiełbasa G, Curila K, et al. Physiology-based electrocardiographic criteria for left bundle branch capture. Heart Rhythm . 2021;18(6):935-943. doi:10.1016/j.hrthm.2021.02.021Figure LegendsFigure 1: Permanent His Bundle PacingPanel A: A 12-lead electrocardiogram (EKG) shows baseline conduction in a patient with exertional intolerance. The PR interval is markedly prolonged and, with exercise, this patient developed AV block. A permanent His-bundle pacemaker was implantedPanel B: An EKG demonstrating permanent His-bundle pacing in the same patient as panel A. Selective His-bundle capture results in reproduction of the intrinsic QRS complex.Figure 2: Non-Selective Left Bundle Branch PacingA 12-Lead electrocardiogram showing non-selective left bundle branch pacing. The paced QRS morphology is not a direct match for native conduction and the QRS duration is longer than at baseline. However, conduction system capture was confirmed with an output dependent QRS morphology change.FiguresFigure 1: Permanent His-Bundle Pacing
Title: Percutaneous Lead Extraction in Patients with Large Vegetations: Limiting our Aspirations.Robert D. Schaller, DO11The Section of Cardiac Electrophysiology, Cardiovascular Division, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PennsylvaniaFunding: This work was supported in part by the Mark Marchlinski EP Research & Education FundKey words: Lead extraction, vegetation, pulmonary embolism, thrombus, aspirationDisclosures: NoneWord count: 1547Transvenous lead extraction (TLE) in the 1960’s involved orthopedic-style pulley systems that joined the exposed portion of the lead to progressively heavier weights hanging from the bed. Sustained tension on the lead was maintained until the patient experienced discomfort, ventricular arrhythmias, or noticeable resistance developed, and was maintained for minutes to days. The location of the lead within the chest was monitored with daily chest radiographs and the ensuingbang of the weight hitting the floor of the intensive care unit signified case conclusion; at which point the patient was assessed. Complications were erratic and included lead laceration and possible migration, injury to the tricuspid valve (TV), myocardial avulsion, tamponade, and death.1 Due to the immature nature of the procedure at that time, it was relegated to infectious indications including lead-related endocarditis, at that time referred to as “catheter fever”.Contemporary TLE has evolved into a highly refined practice with a multitude of tools and predictable results, and procedural indications that now span infection, venous occlusion, management of redundant leads, and access to magnetic resonance imaging.2Procedural imaging with computed tomography (CT) and real-time ultrasound-based tools have similarly changed the TLE experience with identification of adhesions, thrombi, vegetations, and complications.3 Large lead-related masses have historically caused angst due to the possibility of being sheared off by the extraction sheath and embolizing to the lung, and still represent a relative contraindication to percutaneous TLE.2In this issue of the Journal of Cardiovascular Electrophysiology , Giacopelli, et al.4 present the outcomes of 25 consecutive patients (mean age 64 years, 68% male) including 5 with pacemakers, 10 with implantable cardioverter-defibrillators, and 10 with cardiac resynchronization therapy devices, who underwent TLE with vegetations ≥10 mm on transesophageal echocardiography (TEE). Contrast-enhanced CT was performed before and after TLE with 18 (72%) patients showing subclinical pulmonary embolism (PE). Vegetation size (median of 17.5 mm and maximum of 30 mm) did not differ in those with and without PE (20.0 mm vs. 14.0 mm, p=0.116). Complete TLE success was achieved in all patients with 76% requiring advanced tools and 2 needing femoral snaring, and there were no significant procedural complications. In the group with pre-TLE PE, a post-TLE scan confirmed the presence of PE in only 14/18 (78%) and there were no patients with new PE formation. During a median follow-up period of 19.4 months, no re-infection of the new implanted systems was reported and there were 5 deaths (20%); with no differences between the groups. The authors concluded that subclinical PE was common in this clinical scenario but did not influence the complexity or safety of the procedure.Several aspects of this paper warrant comment. No data are reported on the size or location of the PEs nor the time between the first and second CT. It is possible that small PEs would not be identified on subsequent studies days after antibiotics had already been started. Patients also received acute and chronic anticoagulation if PE was identified, which in the setting of vegetations, is generally not indicated and could potentially lead to bleeding. The authors did not provide information regarding infectious pathogens or the timing of culture clearance, which could influence treatment. Additionally, it is unclear which patients received new CIED systems including the type and timing of reimplantation, which might influence subsequent infectious risk. A vascular occlusion balloon was not used in any patients in this report. While this tool is associated with a reduced risk of death in the setting of a superior vena cava laceration when used properly, it has also been shown to be thrombogenic during long dwell times,5 and use could impact post-operative CTs in future studies. Despite utilizing transthoracic echocardiography during TLE, neither TEE nor intracardiac echocardiography were used intraoperatively and thus no information regarding the precise location of the vegetations within the heart is known. Importantly, no information regarding the characteristics of the vegetations other than size was reported.Not all lead-related masses are created equal with two distinct sub-types previously described.6 The first is composed of thickened endocardium and fibrous tissue covering the leads and ultimately forming into connective tissue. These masses, commonly found on leads behind the TV, are caused by a vortical flow pattern leading to low shear stress on the lead surface and provoking neointimal hyperplasia,7 and range from small fibrous strands to large, smooth organized thrombus (Figure, left column). Despite their sterile nature, TLE in the setting of a large, mature thrombus could result in embolization and obstruction of the pulmonary artery resulting in symptomatic PE. The second type, frequently seen in the setting of infective endocarditis, is composed of inflammatory cells, platelets, adhesion molecules, fresh fibrin, and bacteria binding to coagulum and forming vegetations. They are typically longer, more likely to be multi-lobular, and commonly span several chambers of the heart (Figure, right column). These vegetations that are typically acute, with friable finger-like projections, characteristically break apart upon being sheared off during TLE, with reports showing low risk of symptomatic PE.8 Vegetations that are lobular, however, have been associated with worse outcomes.9Despite acute procedural success in the setting of lead-related vegetations, mortality rates at 1 year approach 25%.10 Indeed, despite successful TLE in this report, 20% of patients were dead at 1.5 years. Although complete understanding of the mechanism of these poor outcomes remains unknown, septic emboli, lung abscesses, and infected lead “ghosts” have been implicated.11 Vegetation removal prior to TLE has thus represented an appealing therapeutic option with reports of successful percutaneous aspiration prior to TLE showing promising results, albeit with unknown long-term benefit.12,13 Although the lack of new PEs after TLE in this report does not directly support the effort, cost, and added risk of such a strategy, “debulking” of infectious burden remains a tempting complementary treatment. Importantly, the acute safety of TLE with large vegetations in this study should not be extrapolated to chronic, large lead-related masses, which are more like to cause acute PE if embolized. While aspiration of these sterile masses prior to TLE is appealing from a procedural outcome perspective, their morphologic characteristics, and the imperfect, but evolving, aspiration sheaths currently available are limiting, and requires consideration of surgical extraction. Further advancements in aspiration catheter technology and the development of right ventricular outflow track filters might influence future management.TLE continues to represent the gold standard for the management of lead-related infection.2 Due to the extensive work of the pathfinders in the vanguard of procedural development, the sound of crashing weights has been supplanted by those that power advancing sheaths. Yet despite the safe and predictable nature of modern-day TLE, the sobering long-term mortality of patients with infectious indications remains out of proportion to acute procedural success. While infectious “debulking” continues to represent the most attractive and practical complementary option to address this incongruity, future studies should concentrate both on identification of mass characteristics that suggest success, as well as determining if long-term benefits exist above and beyond lead removal. However, if improvement in clinical outcomes that warrant this added cost and effort are not identified, we should likely limit our aspirations.

Wenjing Li

and 2 more

The sulfur cycle is one of the geochemical element cycles in which microorganisms play a key driving role. The microbial function of soil S cycling in response to desert degradation, however, remains largely unknown. We used metagenomics to analyze the characteristics of microbial communities and their functional genes involved in the S cycles under natural water gradients with three typical halophytes shrubs in the Ebinur Lake Basin Desert, China. Our results showed that the rhizosphere effect, water gradient, and halophyte type played a major role in shaping the S cycle. On the whole, in the rhizosphere type and low water environment, the functional genes involved in the S cycle had high abundance, and the SOX system in Alhagi sparsifolia had a high expression level. In the S cycle network structure, as the soil water content decreased, the complexity in S gene networks increased, showing the characteristics of clustering and high connectivity. Indicates the strengthening mode in microbial interactions with the water content. Interestingly, the negative correlation of the network changed with the water content, and there was more competition among communities under the low water gradient and more cooperation under the high water gradient. Through the correlation between environmental factors and the network, nitrate (NO 3 −) and soil available S (AS) constrained most S gene ecology networks. The key species involved in the S cycle were halophilic microorganisms. These results can enhance the understanding of soil S biogeochemical processes and contribute to the mitigation of desertification by improving soil conservation.

Browse more published preprints

How it works

Upload or create your research work
You can upload Word, PDF, LaTeX as well as data, code, Jupyter Notebooks, videos, and figures. Or start a document from scratch.
Disseminate your research rapidly
Post your work as a preprint. A Digital Object Identifier (DOI) makes your research citeable and discoverable immediately.
Get published in a refereed journal
Track the status of your paper as it goes through peer review. When published, it automatically links to the publisher version.
Learn More
Featured communities
Explore More Communities

Other benefits of Authorea

Multidisciplinary

A repository for any field of research, from Anthropology to Zoology

Comments

Discuss your preprints with your collaborators and the scientific community

Interactive Figures

Not just PDFs. You can publish d3.js and Plot.ly graphs, data, code, Jupyter notebooks

Featured templates
Featured and interactive
Journals with direct submission
Explore All Templates