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Journal of Clinical Medicine Jun 2020Endometriosis is a common, oestrogen driven chronic condition, where endometrium-like epithelial and stromal cells exist in ectopic sites. At present, no curative... (Review)
Review
Endometriosis is a common, oestrogen driven chronic condition, where endometrium-like epithelial and stromal cells exist in ectopic sites. At present, no curative treatments are available and the existing evidence for disease progression is conflicting. The pathogenesis is still unknown and evidently complex, as mechanisms of initiation may depend on the anatomical distribution of endometriotic lesions. However, amongst the numerous theories and plethora of mechanisms, contributions of the fallopian tubes (FT) to endometriosis are rarely discussed. The FT are implicated in all endometriosis associated symptomatology and clinical consequences; they may contribute to the origin of endometriotic tissue, determine the sites for ectopic lesion establishment and act as conduits for the spread of proinflammatory media. Here, we examine the available evidence for the contribution of the human FT to the origin, pathogenesis and symptoms/clinical consequences of endometriosis. We also examine the broader topic linking endometriosis and the FT epithelium to the genesis of ovarian epithelial cancers. Further studies elucidating the distinct functional and phenotypical characteristics of FT mucosa may allow the development of novel treatment strategies for endometriosis that are potentially curative.
PubMed: 32570847
DOI: 10.3390/jcm9061905 -
Experimental Neurology Sep 2019Local application of exogenous agents with neurotrophic properties enhances the regenerative capacity of injured neurons, especially following reconstructions of long... (Review)
Review
Local application of exogenous agents with neurotrophic properties enhances the regenerative capacity of injured neurons, especially following reconstructions of long nerve gaps and delayed nerve repairs. Recent advances in biomaterials and biomedical engineering have provided options for the sustained and controlled release of macromolecules to the peripheral nerve. Here, we review five methods for delivering macromolecules to the peripheral nerve including mini-osmotic pumps, hydrogel-based delivery systems, nerve guidance conduits, electrospun fibers, and nerve wraps. In addition to controlling the release of bioactive macromolecules, the ease of clinical use and versatility in implantation at a variety of "real-world" anatomical locations are key factors in designing an ideal delivery system. The incorporation of both mechanical and biological cues into such devices also helps optimize these systems.
Topics: Animals; Biocompatible Materials; Drug Carriers; Drug Delivery Systems; Humans; Nerve Regeneration; Peripheral Nerves; Tissue Scaffolds
PubMed: 30176220
DOI: 10.1016/j.expneurol.2018.08.014 -
The Journal of Thoracic and... Nov 2021The most durable valved right ventricle to pulmonary artery conduit for the repair of congenital heart defects in patients of different ages, sizes, and anatomic... (Comparative Study)
Comparative Study
OBJECTIVE
The most durable valved right ventricle to pulmonary artery conduit for the repair of congenital heart defects in patients of different ages, sizes, and anatomic substrate remains uncertain.
METHODS
We performed a retrospective analysis of 4 common right ventricle to pulmonary artery conduits used in a single institution over 30 years, using univariable and multivariable models of time-to-failure to analyze freedom from conduit dysfunction, reintervention, and replacement.
RESULTS
Between 1988 and 2018, 959 right ventricle to pulmonary artery conduits were implanted: 333 aortic homografts, 227 pulmonary homografts, 227 composite porcine valve conduits, and 172 bovine jugular vein conduits. Patients weighed 1.6 to 98.3 kg (median 15.3 kg), and median duration of follow-up was 11.4 years, with 505 (52.2%) conduits developing dysfunction, 165 (17.2%) requiring catheter intervention, and 415 (43.2%) being replaced. Greater patient weight, conduit z-score, type and position, as well as catheter intervention were predictors of freedom from replacement. Multivariable analysis demonstrated inferior durability for smaller composite porcine valve conduits, with excellent durability for larger diameter conduits of the same type. Bovine jugular vein conduit longevity was inferior to that of homografts in all but the smallest patients. Freedom from dysfunction at 8 years was 60.7% for aortic homografts, 72% for pulmonary homografts, 51.2% for composite porcine valve conduits, and 41.3% for bovine jugular vein conduits. Judicious oversizing of the conduit improved conduit durability in all patients, but to the greatest extent in patients weighing 5 to 20 kg.
CONCLUSIONS
Pulmonary and aortic homografts had greater durability than xenograft conduits, particularly in patients weighing 5 to 20 kg. Judicious oversizing was the most significant surgeon-modifiable factor affecting conduit longevity.
Topics: Adolescent; Aorta; Bioprosthesis; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Child; Child, Preschool; Female; Follow-Up Studies; Heart Defects, Congenital; Heart Ventricles; Humans; Infant; Male; Multivariate Analysis; Pulmonary Artery; Retrospective Studies; Transplantation, Autologous; Treatment Outcome
PubMed: 33640135
DOI: 10.1016/j.jtcvs.2020.12.144 -
Plant Physiology Aug 2022Understanding mass transport of photosynthates in the phloem of plants is necessary for predicting plant carbon allocation, productivity, and responses to water and...
Understanding mass transport of photosynthates in the phloem of plants is necessary for predicting plant carbon allocation, productivity, and responses to water and thermal stress. Several hypotheses about optimization of phloem structure and function and limitations of phloem transport under drought have been proposed and tested with models and anatomical data. However, the true impact of radial water exchange of phloem conduits with their surroundings on mass transport of photosynthates has not been addressed. Here, the physics of the Munch mechanism of sugar transport is re-evaluated to include local variations in viscosity resulting from the radial water exchange in two dimensions (axial and radial) using transient flow simulations. Model results show an increase in radial water exchange due to a decrease in sap viscosity leading to increased sugar front speed and axial mass transport across a wide range of phloem conduit lengths. This increase is around 40% for active loaders (e.g. crops) and around 20% for passive loaders (e.g. trees). Thus, sugar transport operates more efficiently than predicted by previous models that ignore these two effects. A faster front speed leads to higher phloem resiliency under drought because more sugar can be transported with a smaller pressure gradient.
Topics: Biological Transport; Carbohydrates; Phloem; Plants; Sugars; Water
PubMed: 35588257
DOI: 10.1093/plphys/kiac231 -
The Journal of Surgical Research Mar 2024Study aims were to evaluate the elastic properties of vascular substitutes frequently used for pulmonary artery (PA) replacement, and then to compare their compliance... (Review)
Review
INTRODUCTION
Study aims were to evaluate the elastic properties of vascular substitutes frequently used for pulmonary artery (PA) replacement, and then to compare their compliance and stiffness indexes to those of human PA.
METHODS
A bench-test pulsatile flow experiment was developed to perfuse human cadaveric vascular substitutes (PA, thoracic aorta, human pericardial conduit), bovine pericardial conduit, and prosthetic vascular substitutes (polytetrafluorethylene and Dacron grafts) at a flow and low pulsed pressure mimicking pulmonary circulation. Intraluminal pressure was measured. An ultrasound system with an echo-tracking function was used to monitor vessel wall movements. The diameter, compliance, and stiffness index were calculated for each vascular substitute and compared to the human PA at mean pressures ranging from 10 to 50 mmHg.
RESULTS
The compliance of the PA and the thoracic aorta were similar at mean physiological pressures of 10 mmHg and 20 mmHg. The PA was significantly less compliant than the aorta at mean pressures above 30 mmHg (P = 0.017). However, there was no difference in stiffness index between the two substitutes over the entire pressure range. Compared to the PA, human pericardial conduit was less compliant at 10 mmHg (P = 0.033) and stiffer at 10 mmHg (P = 0.00038) and 20 mmHg (P = 0.026). Bovine pericardial conduit and synthetic prostheses were significantly less compliant and stiffer than the PA for mean pressures of 10, 20, and 30 mmHg. There were no differences at 40 and 50 mmHg.
CONCLUSIONS
Allogenic arterial grafts appear to be the most suitable vascular substitutes in terms of compliance and stiffness for PA replacement.
Topics: Humans; Animals; Cattle; Pulmonary Artery; Ultrasonography; Pulsatile Flow
PubMed: 38039727
DOI: 10.1016/j.jss.2023.10.022 -
Frontiers in Plant Science 2023Vessel traits are key in understanding trees' hydraulic efficiency, and related characteristics like growth performance and drought tolerance. While most plant hydraulic...
Vessel traits are key in understanding trees' hydraulic efficiency, and related characteristics like growth performance and drought tolerance. While most plant hydraulic studies have focused on aboveground organs, our understanding of root hydraulic functioning and trait coordination across organs remains limited. Furthermore, studies from seasonally dry (sub-)tropical ecosystems and mountain forests are virtually lacking and uncertainties remain regarding potentially different hydraulic strategies of plants differing in leaf habit. Here, we compared wood anatomical traits and specific hydraulic conductivities between coarse roots and small branches of five drought-deciduous and eight evergreen angiosperm tree species in a seasonally dry subtropical Afromontane forest in Ethiopia. We hypothesized that largest vessels and highest hydraulic conductivities are found in roots, with greater vessel tapering between roots and equally-sized branches in evergreen angiosperms due to their drought-tolerating strategy. We further hypothesized that the hydraulic efficiencies of root and branches cannot be predicted from wood density, but that wood densities across organs are generally related. Root-to-branch ratios of conduit diameters varied between 0.8 and 2.8, indicating considerable differences in tapering from coarse roots to small branches. While deciduous trees showed larger branch xylem vessels compared to evergreen angiosperms, root-to-branch ratios were highly variable within both leaf habit types, and evergreen species did not show a more pronounced degree of tapering. Empirically determined hydraulic conductivity and corresponding root-to-branch ratios were similar between both leaf habit types. Wood density of angiosperm roots was negatively related to hydraulic efficiency and vessel dimensions; weaker relationships were found in branches. Wood density of small branches was neither related to stem nor coarse root wood densities. We conclude that in seasonally dry subtropical forests, similar-sized coarse roots hold larger xylem vessels than small branches, but the degree of tapering from roots to branches is highly variable. Our results indicate that leaf habit does not necessarily influence the relationship between coarse root and branch hydraulic traits. However, larger conduits in branches and a low carbon investment in less dense wood may be a prerequisite for high growth rates of drought-deciduous trees during their shortened growing season. The correlation of stem and root wood densities with root hydraulic traits but not branch wood points toward large trade-offs in branch xylem towards mechanical properties.
PubMed: 37377798
DOI: 10.3389/fpls.2023.1127292 -
Annals of Vascular Surgery Nov 2023The Society for Vascular Surgery (SVS) developed objective performance goals (OPGs) for lower extremity bypass (LEB) in chronic limb-threatening ischemia (CLTI) based on...
BACKGROUND
The Society for Vascular Surgery (SVS) developed objective performance goals (OPGs) for lower extremity bypass (LEB) in chronic limb-threatening ischemia (CLTI) based on studies that included patients who were at good risk for open revascularization. In the endovascular era, many LEB patients have had prior interventions, and most would be considered high-risk by the original SVS OPG standards. The goal of this study is to characterize a contemporary patient population undergoing LEB for CLTI and determine if outcomes remain commensurate with the parameters established by the SVS OPG.
MATERIALS AND METHODS
All patients who underwent LEB for CLTI over a 10-year period (2012-2021) were identified. Patients were stratified into low- and high-risk categories based upon the clinical, conduit, and anatomic parameters used in the SVS OPG. Limb salvage at 1 year and amputation-free survival, a composite outcome of major amputation and mortality, at 1 year were compared with the SVS OPG cohort. Primary, assisted, and secondary patency at 1 and 3 years were also evaluated using Kaplan-Meier survival analysis.
RESULTS
There were 169 LEBs performed for CLTI. One hundred and two (60.36%) males, 101 (59.76%) current or former smokers, 115 (68.05%) with hypertension, 69 (40.83%) with diabetes mellitus, and 40 (23.67%) with coronary artery disease. Median age was 71.84 years, and mean follow-up was 2.17 years. 65 (38.46%) had a prior ipsilateral endovascular intervention, and 18 (10.65%) were redo bypasses. 21 (12.43%) were deemed clinically high-risk, 44 (26.04%) were high-risk conduits, and 118 (69.82%) had high-risk anatomic factors. Freedom from amputation at 1 year was 87.05% in this cohort which was similar to the overall SVS OPG cohort (88.9%). Amputation-free survival at 1 year was 77.78%, which was also similar to the overall SVS OPG cohort (76.5%). Primary patency at one and three years was 46.84% and 37.59%, assisted patency at one and three years was 61.87% and 44.81%, and secondary patency at one and three years was 72.13% and 61.16%.
CONCLUSIONS
The majority of patients undergoing LEB in the endovascular era meet the SVS OPG criteria for high risk. Despite this, the 1-year limb salvage and amputation-free survival in this cohort were equivalent to the SVS OPG LEB cohort. This supports the continued use of LEB for limb salvage in high-risk patients and those who have failed endovascular approaches.
Topics: Male; Humans; Aged; Female; Treatment Outcome; Ischemia; Peripheral Arterial Disease; Vascular Surgical Procedures; Limb Salvage; Risk Factors; Lower Extremity; Retrospective Studies; Endovascular Procedures
PubMed: 37169246
DOI: 10.1016/j.avsg.2023.04.027 -
Current Opinion in Cardiology Nov 2022The recent American College of Cardiology/American Heart Association/Society for Cardiovascular Angiography and Interventions Guidelines for Coronary Artery... (Review)
Review
PURPOSE OF REVIEW
The recent American College of Cardiology/American Heart Association/Society for Cardiovascular Angiography and Interventions Guidelines for Coronary Artery Revascularization have raised concerns on the survival benefits of coronary artery bypass grafting (CABG) over guideline-directed medical therapy (GDMT) in stable coronary artery disease (CAD) and appropriate conduit selection for CABG. This review summarizes the evidence supporting CABG for stable CAD and use of the radial artery as a conduit for CABG.
RECENT FINDINGS
CABG has consistently demonstrated a survival benefit over GDMT for patients with stable multivessel CAD. These benefits were more pronounced in patients with diabetes and/or anatomically complex coronary artery disease. The recently published International Study of Comparative Health Effectiveness with Medical and Invasive Approaches trial was not designed to and did not include an appropriate patient population to compare revascularization with CABG to GDMT. These results should thus be viewed in the context of previously published studies. Furthermore, increasing evidence suggests that use of a radial artery in CABG is associated with reduced myocardial infarction and repeat revascularization. This should be considered when selecting the appropriate conduits based on underlying patient factors.
SUMMARY
Readers should be cautious when applying these guidelines broadly. Appropriate consideration of patient and anatomic factors, and in consultation with a multidisciplinary heart team, is important to achieve the best outcomes for patients.
Topics: Coronary Artery Bypass; Coronary Artery Disease; Humans; Myocardial Infarction; Percutaneous Coronary Intervention; Treatment Outcome
PubMed: 36094460
DOI: 10.1097/HCO.0000000000000994 -
General Thoracic and Cardiovascular... Sep 2020Patients with functional single ventricle and right atrial isomerism (RAI) often have multiform cardiac pulmonary venous (PV) connection, which could be a risk factor...
BACKGROUND
Patients with functional single ventricle and right atrial isomerism (RAI) often have multiform cardiac pulmonary venous (PV) connection, which could be a risk factor for pulmonary venous obstruction (PVO) after extracardiac total cavopulmonary connection (EC-TCPC) owing to compression of the conduit.
OBJECTIVE
To investigate the anatomical risk factors for PVO after EC-TCPC in RAI.
METHODS
Twenty-nine patients with RAI without extracardiac total anomalous pulmonary venous connection were enrolled. No patients had PVO before EC-TCPC. A total of 14 and 15 patients had PV orifices ipsilateral and contralateral to the extracardiac conduit, respectively. The former 14 patients were assigned to two groups based on development of PVO after EC-TCPC (groups O and N). The pre- and post-operative cardiac morphologies and their relationship with the conduit were compared.
RESULTS
After the EC-TCPC, the pressure gradients between the atrium and the PV were 5.0 ± 2.5 and 0.44 ± 0.2 mmHg in groups O and N, respectively (p < 0.01); however, the pressure gradients in the left and right PVs were not significantly different, suggesting stenosis of the common PV orifice. The ratio of the horizontal distance from the vertebrae to the PV orifice and to the lateral edge of the atrium was significantly higher (0.38 ± 0.2 vs. 0.17 ± 0.1; p = 0.04) and the orifice was smaller (8.9 ± 2.0 vs. 15 ± 4.7 mm; p < 0.01) in group O than in group N.
CONCLUSION
In cases with ipsilateral locations of the conduit and PV orifice, small size and more lateral location of the PV orifice may be preoperative risk factors for development of PVO.
Topics: Child, Preschool; Female; Fontan Procedure; Heart Atria; Heart Defects, Congenital; Humans; Male; Postoperative Period; Pulmonary Circulation; Pulmonary Veins; Pulmonary Veno-Occlusive Disease
PubMed: 32036565
DOI: 10.1007/s11748-020-01316-3 -
Radiographics : a Review Publication of... 2020Diagnostic imaging after orthotopic liver transplant focuses primarily on depicting complications related to surgical hepatic vascular and biliary anastomoses. Less... (Review)
Review
Diagnostic imaging after orthotopic liver transplant focuses primarily on depicting complications related to surgical hepatic vascular and biliary anastomoses. Less common preexisting vascular conditions include congenital anatomic variants, atherosclerosis, chronic portal venous thrombosis, splenic artery and variceal steal phenomena, and transarterial embolization (TAE) for hepatocellular carcinoma (HCC). If unappreciated or left untreated preoperatively, these conditions negatively impact the transplant by impairing hepatic arterial or portal vascular inflow. Many of the complications related to preexisting vascular conditions can be prevented or mitigated by proper performance and careful evaluation of preoperative imaging studies. The authors describe the diagnosis and treatment of complications arising from narrowing of the celiac axis by atherosclerosis and the median arcuate ligament, variant anatomy of the hepatic artery, insufficiency of the portal vein requiring surgical conduits, and large varices or an enlarged splenic artery and spleen that may steal blood and compromise hepatic arterial or venous inflow. While preoperative evaluation primarily involves CT and MRI, postoperative diagnosis involves screening with sonography and confirmation with other modalities. We propose the use of a preoperative checklist of vascular status and measurements in patients undergoing liver transplant. Reports of imaging studies in recipients after transplant should include details of surgical vascular anastomoses and conduits, any history of HCC and preoperative TAE, details of the preoperative α-fetoprotein levels, and any unusual procedures or pathologic findings in the explanted liver that may affect postoperative surveillance. The authors review the pretransplant imaging evaluation of vascular and HCC issues that may affect surgical outcomes and methods to help recognize complications after transplant that can arise from these conditions.RSNA, 2020.
Topics: Comorbidity; Humans; Liver Transplantation; Postoperative Complications
PubMed: 32281901
DOI: 10.1148/rg.2019190120