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Frontiers in Plant Science 2023The cortex-to-stele ratio (CSR), as it increases from thin- to thick-root species in angiosperms, is theorised to effectively reflect a compensation for the 'lag' of...
The cortex-to-stele ratio (CSR), as it increases from thin- to thick-root species in angiosperms, is theorised to effectively reflect a compensation for the 'lag' of absorption behind transportation. But it is still not known if this compensatory effect exists in gymnosperm species or governs root structure and function within species. Here, anatomical, morphological, and tissue chemical traits of absorptive roots were measured in three temperate angiosperm and three gymnosperm species. Differences in the CSR and the above functional traits, as well as their intraspecific associations, were analyzed and then compared between angiosperms and gymnosperms. At the intraspecific level, the CSR decreased with increasing root order for all species. The expected functional indication of the CSR was consistent with decreases in specific root length (SRL) and N concentration and increases in the C to N ratio (C:N ratio) and the number of and total cross-sectional area of conduits with increasing root order, demonstrating that the CSR indicates the strength of absorption and transportation at the intraspecific level, but intraspecific changes are due to root development rather than the compensatory effect. These trends resulted in significant intraspecific associations between the CSR and SRL ( = 0.36 ~ 0.80), N concentration ( = 0.48 ~ 0.93), the C:N ratio ( = 0.47 ~ 0.91), and the number of ( = 0.21 ~ 0.78) and total cross-sectional area ( = 0.29 ~ 0.72) of conduits in each species (< 0.05). The overall mean CSR of absorptive roots in angiosperms was four times greater than in gymnosperms, and in angiosperms, the CSR was significantly higher in thick- than in thin-rooted species, whereas in gymnosperms, the interspecific differences were not significant ( > 0.05). This suggests that the compensation for the lag of absorption cortex thickness regulation was stronger in three angiosperm species than in three gymnosperm species. In addition, there was poor concordance between angiosperms and gymnosperms in the relationships between CSRs and anatomical, morphological, and tissue chemical traits. However, these gymnosperm species show a more stable intraspecific functional association compared to three angiosperm species. In general, absorptive root CSRs could manifest complex strategies in resource acquisition for trees at both intra- and interspecific levels.
PubMed: 36743504
DOI: 10.3389/fpls.2023.1061503 -
Integrative and Comparative Biology Aug 2023Mammals have presumably evolved to adapt to a diverse range of ambient environmental conditions through the optimized heat and mass exchange. One of the crucial...
Mammals have presumably evolved to adapt to a diverse range of ambient environmental conditions through the optimized heat and mass exchange. One of the crucial biological structures for survivability is the nose, which efficiently transports and thermally preconditions the external air before reaching the internal body. Nasal mucosa and cavity help warm and humidify the inhaled air quickly. Despite its crucial role, the morphological features of mammal noses and their effect in modulating the momentum of the inhaled air, heat transfer dynamics, and particulate trapping remain poorly understood. Tortuosity of the nasal cavity in high-olfactory mammalian species, such as pigs and opossum, facilitates the formation of complex airflow patterns inside the nasal cavity, which leads to the screening of particulates from the inhaled air. We explored basic nasal features in anatomically realistic nasal pathways, including tortuosity, radius of curvature, and gap thickness; they show strong power-law correlations with body weight. Complementary inspection of tortuosity with idealized conduits reveals that this quantity is central in particle capture efficiency. Mechanistic insights into such nuances can serve as a tipping point to transforming nature-based designs into practical applications. In-depth characterization of the fluid-particle interactions in nasal cavities is necessary to uncover nose mechanistic functionalities. It is instrumental in developing new devices and filters in a number of engineering processes.
Topics: Swine; Animals; Nose; Nasal Cavity; Smell; Hot Temperature; Adaptation, Physiological; Computer Simulation; Mammals
PubMed: 36731869
DOI: 10.1093/icb/icad005 -
Frontiers in Pediatrics 2022A limiting factor in using vascular conduits in the pediatric/newborn population is their inability to grow. Many complex congenital heart diseases require palliative...
A limiting factor in using vascular conduits in the pediatric/newborn population is their inability to grow. Many complex congenital heart diseases require palliative surgery, but using rigid and nonexpandable conduits does not allow the structures to grow and anticipates the need for redo surgery. In newborns, a way to increase the palliation time according to the patient's growth is desirable. In recent years, expandable shunts () have been developed. According to recent material studies, a shunt could increase diameter after endovascular balloon dilatation. In this case report, we describe the first case of endovascular Blalock-Thomas-Taussig shunt (mBT) shunt expansion in a Tetralogy of Fallot / atrial-ventricular Septal Defect complete (TOFAVSDc) patient with trisomy 21 who went to palliative treatment for tracheomalacia (noncardiac lesion association), severe pulmonary arteries hypoplasia, and low weight. This case introduces the "" in the clinical scenario of selected growing patients where the lifetime of the Blalock-Thomas-Taussig (BT) shunt, anatomic substrates, and complexity of clinical status may require an additional palliation time. The limitation of endovascular conduit expansion is the fragility of the anastomosis site. The anastomosis site is a lesser strength structure of the conduit, and dilatation could develop procedure complications. For this reason, in this paper, we introduced our project design: a new technique () that consists, before surgical implantation, of pre-expansion of the proximal and distal anastomotic parts of the shunt to obtain an increase of 30% in size of both anastomotic sides, preventing stress- and stretch-related lesion of future balloon dilatation.
PubMed: 36683796
DOI: 10.3389/fped.2022.1073412 -
Biomedicines Jan 2023Saphenous vein graft (SVG) is a cardiac surgical practice used to create a cardiac bypass in cases of coronary artery obstruction. It consists of a surgical procedure... (Review)
Review
BACKGROUND AND OBJECTIVES
Saphenous vein graft (SVG) is a cardiac surgical practice used to create a cardiac bypass in cases of coronary artery obstruction. It consists of a surgical procedure that involves the creation of an aorto-coronary communication by a venous conduit (saphenous vein) to bypass coronary stenosis and allow cardiac revascularization. This practice can be affected by early and late complications. The most feared complication is graft aneurysm or pseudoaneurysm degeneration and rupture which are considered late complications. This paper presents a rare case of SVG aneurysmal rupture that occurred 24 h after surgery and a review of the literature to provide a general look at the state of knowledge.
MATERIALS AND METHODS
The systematic review was carried out using the guidelines according to the PRISMA method.
RESULTS
Cases of aneurysmal rupture have never been described prior to one month after surgery. The male sex and subjects under 45 are the most affected by this complication. Death occurs in less than half of the cases, being more frequent in young people. Performing a CT or angio-CT examination led to the diagnosis.
CONCLUSIONS
It is impossible to estimate the implanted vessel's quality, so postoperative follow-up is fundamental. Transesophageal ultrasound can be useful, and hematochemical tests are valuable early diagnostic tools, whrease CT and angio-CT can be useful even months after surgery. Forensic analysis should always perform an autopsy and graft histological examination.
PubMed: 36672728
DOI: 10.3390/biomedicines11010220 -
Operative Neurosurgery (Hagerstown, Md.) Feb 2023Extracranial to intracranial bypass is used to augment and/or replace the intracranial circulation for various pathologies. The superficial temporal artery is the...
BACKGROUND
Extracranial to intracranial bypass is used to augment and/or replace the intracranial circulation for various pathologies. The superficial temporal artery is the mainstay donor for pedicled bypasses to the anterior circulation but can be limited by its variable size, low native flow rates, and potential scalp complications. Interposition grafts such as the radial artery or greater saphenous vein are alternatives but are sometimes limited by size mismatch, length needed to reach the extracranial circulation, and loss of inherent vascular elasticity. Interposition grafts between the maxillary artery (IMA) and middle cerebral artery (MCA) address these limitations.
OBJECTIVE
To explore the feasibility of harvesting the IMA through an endoscopic transnasal, transmaxillary approach to perform a direct IMA to MCA bypass.
METHODS
Combined transcranial and endoscopic endonasal dissections were performed in embalmed human cadavers to harvest the IMAs for intracranial transposition and direct anastomosis to the MCA. Donor and recipient vessel calibers were measured and recorded.
RESULTS
A total of 8 procedures were performed using the largest and distal-most branches of the IMA (the sphenopalatine branch and the descending palatine branch) as pedicled conduits to second division of middle cerebral artery (M2) recipients. The mean diameter of the IMA donors was 1.89 mm (SD ± 0.42 mm), and the mean diameter of the recipient M2 vessels was 1.90 mm (SD ± 0.46 mm).
CONCLUSION
Endoscopic harvest of the IMA using a transnasal, transmaxillary approach is a technically feasible option offering an excellent size match to the M2 divisions of the MCA and the advantages of a relatively short, pedicled donor vessel.
Topics: Humans; Middle Cerebral Artery; Maxillary Artery; Feasibility Studies; Cerebral Revascularization; Endoscopes
PubMed: 36637306
DOI: 10.1227/ons.0000000000000492 -
Radiology and Oncology Dec 2022Hyperspectral imaging (HSI) is a promising imaging modality that uses visible light to obtain information about blood flow. It has the distinct advantage of being... (Review)
Review
BACKGROUND
Hyperspectral imaging (HSI) is a promising imaging modality that uses visible light to obtain information about blood flow. It has the distinct advantage of being noncontact, nonionizing, and noninvasive without the need for a contrast agent. Among the many applications of HSI in the medical field are the detection of various types of tumors and the evaluation of their blood flow, as well as the healing processes of grafts and wounds. Since tumor perfusion is one of the critical factors in oncology, we assessed the value of HSI in quantifying perfusion changes during interventions in clinical oncology through a systematic review of the literature.
MATERIALS AND METHODS
The PubMed and Web of Science electronic databases were searched using the terms "hyperspectral imaging perfusion cancer" and "hyperspectral imaging resection cancer". The inclusion criterion was the use of HSI in clinical oncology, meaning that all animal, phantom, , experimental, research and development, and purely methodological studies were excluded.
RESULTS
Twenty articles met the inclusion criteria. The anatomic locations of the neoplasms in the selected articles were as follows: kidneys (1 article), breasts (2 articles), eye (1 article), brain (4 articles), entire gastrointestinal (GI) tract (1 article), upper GI tract (5 articles), and lower GI tract (6 articles).
CONCLUSIONS
HSI is a potentially attractive imaging modality for clinical application in oncology, with assessment of mastectomy skin flap perfusion after reconstructive breast surgery and anastomotic perfusion during reconstruction of gastrointenstinal conduit as the most promising at present.
Topics: Animals; Mastectomy; Medical Oncology; Diagnostic Imaging; Phantoms, Imaging; Contrast Media
PubMed: 36503709
DOI: 10.2478/raon-2022-0051 -
Advanced Science (Weinheim,... Feb 2023Peripheral nerve injury is a serious medical problem with limited surgical and clinical treatment options. It is of great significance to integrate multiple guidance...
Combining a Density Gradient of Biomacromolecular Nanoparticles with Biological Effectors in an Electrospun Fiber-Based Nerve Guidance Conduit to Promote Peripheral Nerve Repair.
Peripheral nerve injury is a serious medical problem with limited surgical and clinical treatment options. It is of great significance to integrate multiple guidance cues in one platform of nerve guidance conduits (NGCs) to promote axonal elongation and functional recovery. Here, a multi-functional NGC is constructed to promote nerve regeneration by combining ordered topological structure, density gradient of biomacromolecular nanoparticles, and controlled delivery of biological effectors to provide the topographical, haptotactic, and biological cues, respectively. On the surface of aligned polycaprolactone nanofibers, a density gradient of bioactive nanoparticles capable of delivering recombinant human acidic fibroblast growth factor is deposited. On the graded scaffold, the proliferation of Schwann cells is promoted, and the directional extension of neurites from both PC12 cells and dorsal root ganglions is improved in the direction of increasing particle density. After being implanted in vivo for 6 and 12 weeks to repair a 10-mm rat sciatic nerve defect, the NGC promotes axonal elongation and remyelination, achieving the regeneration of the nerve not only in anatomical structure but also in functional recovery. Taken together, the NGC provides a favorable microenvironment for peripheral nerve regeneration and holds great promise for realizing nerve repair with an efficacy close to autograft.
Topics: Rats; Animals; Humans; Sciatic Nerve; Axons; Tissue Scaffolds; Nerve Regeneration; Nanoparticles
PubMed: 36494181
DOI: 10.1002/advs.202203296 -
Journal of Vascular Surgery Apr 2023Patients with peripheral artery disease (PAD) requiring lower extremity revascularization (LER) have a high risk of adverse limb and cardiovascular events. The results... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Patients with peripheral artery disease (PAD) requiring lower extremity revascularization (LER) have a high risk of adverse limb and cardiovascular events. The results from the VOYAGER PAD (efficacy and safety of rivaroxaban in reducing the risk of major thrombotic vascular events in subjects with symptomatic peripheral artery disease undergoing peripheral revascularization procedures of the lower extremities) trial have demonstrated that rivaroxaban significantly reduced this risk with an overall favorable net benefit for patients undergoing surgical revascularization. However, the efficacy and safety for those treated by surgical bypass, including stratification by bypass conduit (venous or prosthetic), has not yet been described.
METHODS
In the VOYAGER PAD trial, patients who had undergone surgical and endovascular infrainguinal LER to treat PAD were randomized to rivaroxaban 2.5 mg twice daily or placebo on top of background antiplatelet therapy (aspirin 100 mg to be used in all and clopidogrel in some at the treating physician's discretion) and followed up for a median of 28 months. The primary end point was a composite of acute limb ischemia, major amputation of vascular etiology, myocardial infarction, ischemic stroke, and cardiovascular death. The principal safety outcome was major bleeding using the TIMI (thrombolysis in myocardial infarction) scale. The index procedure details, including conduit type (venous vs prosthetic), were collected at baseline.
RESULTS
Among 6564 randomized patients, 2185 (33%) had undergone surgical LER. Of these 2185 patients, surgical bypass had been performed for 1448 (66%), using a prosthetic conduit for 773 patients (53%) and venous conduit for 646 patients (45%). Adjusting for the baseline differences and anatomic factors, the risk of unplanned limb revascularization in the placebo arm was 2.5-fold higher for those receiving a prosthetic conduit vs a venous conduit (adjusted hazard ratio [HR], 2.53; 95% confidence interval [CI], 1.65-3.90; P < .001), and the risk of acute limb ischemia was three times greater (adjusted HR, 3.07; 95% CI, 1.84-5.11; P < .001). The use of rivaroxaban reduced the primary outcome for the patients treated with bypass surgery (HR, 0.78; 95% CI, 0.62-0.98), with consistent benefits for those receiving venous (HR, 0.66; 95% CI, 0.49-0.96) and prosthetic (HR, 0.87; 95% CI, 0.66-1.15) conduits (P = .254). In the overall trial, major bleeding using the TIMI scale was increased with rivaroxaban. However, the numbers for those treated with bypass surgery were low (five with rivaroxaban vs nine with placebo; HR, 0.55; 95% CI, 0.18-1.65) and not powered to show statistical significance.
CONCLUSIONS
Surgical bypass with a prosthetic conduit was associated with significantly higher rates of major adverse limb events relative to venous conduits even after adjustment for patient and anatomic characteristics. Adding rivaroxaban 2.5 mg twice daily to aspirin or dual antiplatelet therapy significantly reduced this risk, with an increase in the bleeding risk, but had a favorable benefit risk for patients treated with bypass surgery, regardless of conduit type. Rivaroxaban should be considered after lower extremity bypass for symptomatic PAD to reduce ischemic complications of the heart, limb, and brain.
Topics: Humans; Rivaroxaban; Platelet Aggregation Inhibitors; Aspirin; Peripheral Arterial Disease; Hemorrhage; Myocardial Infarction; Ischemia; Lower Extremity; Treatment Outcome
PubMed: 36470531
DOI: 10.1016/j.jvs.2022.11.062 -
Cardiovascular Engineering and... Apr 2023Tetralogy of Fallot and other conditions affecting the right ventricular outflow tract (RVOT) are common in pediatric patients, but there is a lack of quantitative...
PURPOSE
Tetralogy of Fallot and other conditions affecting the right ventricular outflow tract (RVOT) are common in pediatric patients, but there is a lack of quantitative comparison among techniques for repairing or replacing the pulmonary valve. The aim of this study was to develop a robust in vitro system for quantifying flow conditions after various RVOT interventions.
METHODS
An infant-sized mock circulatory loop that includes a 3D-printed RVOT anatomical model was developed to evaluate flow conditions after different simulated surgical repairs. Physiologically correct flow and pressure were achieved with custom compliant tubing and a tunable flow restrictor. Pressure gradient, flow regurgitation, and coaptation height were measured for two monocusp leaflet designs after tuning the system with a 12 mm Hancock valved conduit.
RESULTS
Measurements were repeatable across multiple samples of two different monocusp designs, with the wider leaflet in the 50% backwall model consistently exhibiting lower pressure gradient but higher regurgitation compared to the leaflet in the 40% backwall model. Coaptation height was measured via direct visualization with endoscopic cameras, revealing a shorter area of contact for the wider leaflet (3.3-4.0 mm) compared to the narrower one (4.3 mm).
CONCLUSION
The 3D-printed RVOT anatomical model and in vitro pulmonary circulatory loop developed in this work provide a platform for planning and evaluating surgical interventions in the pediatric population. Measurements of regurgitation, pressure gradient, and coaptation provide a quantitative basis for comparison among different valve designs and positions.
Topics: Infant; Child; Humans; Tetralogy of Fallot; Ventricular Outflow Obstruction; Pulmonary Valve; Heart Ventricles; Pulmonary Circulation; Treatment Outcome; Heart Valve Prosthesis
PubMed: 36456745
DOI: 10.1007/s13239-022-00648-w -
Medicine Nov 2022Double-outlet left ventricle (DOLV) is a rare congenital cardiac malformation in which both great arteries arise entirely or predominantly from the left ventricle. An...
RATIONALE
Double-outlet left ventricle (DOLV) is a rare congenital cardiac malformation in which both great arteries arise entirely or predominantly from the left ventricle. An extracardiac conduit is the first surgical option for repairing DOLV, specifically because its placement of the extracardiac conduit can be customized to accommodate all possible anatomical variations. The bovine jugular veins and homograft valves are often used as conduits. There have been no reports on the use of handmade trileaflet-valved conduits for correcting DORV.
PATIENT CONCERNS
A 1-year old male was admitted for significant heart murmur and cyanosis, according to the results of transthoracic echocardiography, computed tomography angiography, and cardioangiography, and was diagnosed with DOLV and pulmonary stenosis.
DIAGNOSIS AND INTERVENTIONS
The patient underwent biventricular repair with a handmade trileaflet-valved extracardiac conduit. The postoperative course was uneventful.
OUTCOME
Three months after the surgery, TTF indicated mild right ventricular outflow obstruction and pulmonary valve regurgitation.
LESSONS
Correction of the left ventricular double outlet with a handmade trileaflet-valved conduit has been shown to have excellent performance, and long-term outcomes should be followed over time.
Topics: Male; Animals; Cattle; Humans; Infant; Heart Ventricles; Pulmonary Valve Stenosis; Prostheses and Implants; Echocardiography; Cyanosis
PubMed: 36451474
DOI: 10.1097/MD.0000000000032070