Tissue Pressure Research Articles

Anatomical Studies on the Morphology and Topography of Cavity Lymphnodes in Pigs

The lymphatic system, supported by the lymphatic vessels, is a vascular network in higher vertebrates, having essential roles, such as regulating tissue pressure, monitoring the immune system and absorbing fats from the diet. The lymphatic vessels constitute an unidirectional system that transports fluids and proteins, taking them from the interstitial space and returning them to the bloodstream. Objectives: The objectives pursued in this study are the following: to identify the topography of the main cavity lymph nodes and the morphological and topographic variants that may occur; to identify the main interspecific histological characteristics of vessels and lymph nodes in pigs. Materials and methods: The study was carried out on 20 animals weighing 25-30 kg, aged about 3.5 months, of both sexes. They came from private breeders. Ultrasonographic investigations were also performed on half of them. The macro- and microscopic anatomical studies as well as the ultrasonographic investigations were performed at the Faculty of Veterinary Medicine in Bucharest. For macroscopic and topographic analysis, lymph nodes in both the thoracic and abdominal cavities were examined "in situ". Results. Caudal mediastinal lymph nodes were always fewer in number (between one and three). They were associated with the esophagus, immediately behind the tracheobronchial and ventral lymph nodes of the aorta. The afferents originated from the pericardium, the caudal part of the mediastinum and the corresponding part of the esophagus. The efferents connected to the tracheobronchial lymph nodes or could also approach some thoraco-aortic lymph nodes. The lumbo-aortic lymph nodes were located on the lateral surfaces of the aorta, starting from the diaphragmatic orifice to the origin of the deep iliac circumflex artery. The iliac lymphocenters were represented by large lymph nodes that formed a bundle at the origin of the celiac artery. Colic lymph nodes were located along the path of the right colonic artery. Splenic lymph nodes were placed on the path of the homonymous vessels. Their topography was between the aorta and the hilum of the spleen. In this sector there could be 2-4 lymph nodes, but there were others (2-5) located along the upper quarter of the spleen. The jejunal lymph nodes formed a double chain in the middle of the jejuno-ileum meso, about 30 cm long. The caudal mesenteric lymph nodes were reduced, located dorsally by the descending colon on the path of the caudal mesenteric artery. Conclusions. In the case of mediastinal lymph nodes, the anterior ones are present, but their topography differs significantly from individual to individual. The most important groups of visceral lymph nodes are jejunal and colic. The most important parietal lymphocenter is the ileosacral one. In it, we were able to describe for the first time some individual variants, namely: lateral iliac lymph nodes dominant in volume compared to the medial ones, the absence in some cases (10%) of anorectal lymph nodes in some specimens, in which, however, a compensation was observed by the development of a chain of small units on the path of the median sacral artery.

Lead-induced actin polymerization aggravates neutrophil extracellular trap formation and contributes to vascular inflammation.

Lead (Pb) exposure is widely acknowledged as a risk factor for cardiovascular diseases. Previous studies have established neutrophil involvement in Pb-induced cardiovascular injuries; however, the underlying mechanisms remain unclear. To address this knowledge gap, the binding targets of Pb in neutrophils and their roles in regulating neutrophil extracellular trap (NET) formation were investigated. Furthermore, their impact on Pb-induced vascular inflammation and other cardiovascular injuries was studied in mice. Our findings indicate, for the first time, that Pb binds to β-actin in neutrophils, influencing NET formation. Inhibition of actin polymerization reduces the release of extracellular myeloperoxidase, neutrophil elastase, and citrullinated histone H3, indicating an impediment in NET formation. Furthermore, Pb exposure exacerbates blood pressure and vascular inflammation in vascular tissues, leading to abnormal aortic blood flow in mice. These injuries are potentially associated with NET formation, which is supported by the positive correlation between NETs and vascular inflammation. Importantly, the inhibition of actin polymerization mitigates Pb-induced vascular inflammation and regulates systolic blood pressure by reducing NET formation. Collectively, our findings provide novel insights into the mechanism underlying Pb-induced cardiovascular injury, contributing to the management of the escalating risk associated with Pb-induced cardiovascular damage.

The role of sympathetic control in bone vasculature: insights from spinal cord injury.

Bone vasculature is richly innervated by an extensive network of sympathetic nerves. However, our understanding of bone blood flow regulation and its contribution to human bone health is limited. Here, we further our previous findings by characterizing bone vascular responses in the absence of sympathetic control - studying individuals with spinal cord injury (SCI), a population with known peripheral sympathetic disruption. We assessed tibial vascular responses to isometric handgrip exercise (IHE) in individuals with SCI (n = 12) and controls (n = 12). When sustained to fatigue, IHE increases perfusion pressure and sympathetic vasoconstriction in the non-active tissues of the legs. During IHE, we measured blood pressure, whole leg blood velocity via ultrasound, and tibial perfusion (as hemoglobin content) via near-infrared spectroscopy. Controls demonstrated active sympathetic vasoconstriction in the whole leg (i.e., increased vascular resistance, arterial pressure/leg blood velocity) and tibia (i.e., decreased hemoglobin). In contrast, SCI individuals demonstrated modest whole leg vasoconstriction with lesser increases in vascular resistance than controls (P<.04). Tibial vasculature evidenced absent or blunted vasoconstriction compared to controls (P<.01), indicated by increasing tibial hemoglobin until plateauing at higher pressure levels. This suggests that, in the absence of sympathetic control, tibial vascular response may involve other regulatory mechanisms like myogenic vasoconstriction. Lastly, we leveraged existent whole-body Dual Energy X-ray Absorptiometry scans in a subgroup of nine individuals with SCI and we found a strong relationship between leg bone mineral density (BMD) and tibial hemoglobin at end of IHE (r2 = 0.67, P<.01). Our findings indicate that in the absence of sympathetic mechanisms, myogenic control may play a compensatory role in regulating blood flow, though to a lesser extent in bone compared to muscle. The close relationship between lesser declines in bone blood content and higher BMD underscores the link between blood flow and bone health.

The Protective Capability of Helmet Against Blast Wave to Prevent Traumatic Brain Injury

Abstract Blast-induced traumatic brain injury (b-TBI) is a kind of prevalent military injury in combat casualty care, yet little is known about the protective capability of typical helmet structure against blast wave. In this study, a head model under blast was used for experimentally and numerically research. A finite element model with a typical human head structure was established. Tests on the distribution of air pressure field of the unprotected head, typical combat helmet protected head, combat helmet protected head with face shield, motorcycle helmet protected head were carried out after the explosion of 50gTNT action at 1m. Various test conditions were analyzed by numerical simulation method. The interaction law between the blast wave and the head under the protection of different helmet structures was obtained. Combined with the brain tissue pressure, the protective effect of different helmet structures on the blast wave was analyzed. The results show that increasing the helmet protection area is a good protection strategy for blast wave and the research suggests a possible protection strategy for blast wave often associated with military concussions.

Sitting pressure during wheelchair propulsion and handcycling: effects of backrest angle, movement intensity and cushion type

Purpose: The main aim of this study was to compare sitting pressure (peak pressure index (PPI) and peak pressure gradient (PPG)) between a daily wheelchair and fixed-frame handcycle, thereby assessing the effect of handcycle backrest angle, movement intensity and cushion type. Materials and methods: Twenty able-bodied participants performed static and dynamic (two intensities) tests in a wheelchair and handcycle. A honeycomb wheelchair cushion and standard foam handcycle cushion were used. Handcycle backrest angles were 45° and 60°. The PPI and PPG at the sacro-coccygeal (SC) and ischial tuberosity (IT) regions were determined with a pressure mat. Results: PPI at the IT-region was higher in the 60° handcycle condition than in the wheelchair (p = 0.04), while PPG at the IT-region did not differ significantly between the wheelchair and handcycle conditions (p > 0.05). PPI and PPG were higher at the 45° handcycle SC-region compared to the wheelchair IT-region (p < 0.03). PPI and PPG at the IT-region were higher with the 60° than with the 45° backrest angle (p < 0.01), while at the SC-region PPI was higher with the 45° backrest angle (p = 0.047). No clear influence of movement intensity was found. PPI and PPG at the IT-region and PPI of the SC-region in the handcycle were significantly lower with the wheelchair cushion than with the handcycle cushion (p < 0.01). Conclusion: Overall, sitting pressure was higher in the handcycle compared to the daily wheelchair. For handcyclists using an upright position, it is recommended to use a cushion designed to redistribute pressure, thereby reducing internal tissue pressure and shear.

Bioinspired intratumoral infusion port catheter improves local drug delivery in the liver

Tumor immune modulation can be achieved using intratumoral injection of different immunomodulators during different phases of the cancer-immunity cycle. Intratumoral infusion catheters have been used in brain tumors, but these are not suitable outside the brain, where breathing motion results in catheter migration. Here, we use microstereolithography to manufacture a barbed sidehole catheter, modeled after the barbs in a bee stinger, where the barbs maintain the catheter position in the tumor, and sideholes within the barbs infuse drug into tumor tissue. In pig liver, we demonstrated 183-fold higher local drug concentration using the barbed sidehole catheter, compared to intravenous injection of water-soluble drug. High resistance sideholes and pulsatile injection both generate higher pressure in the catheter, which overcomes the tissue pressure, resulting in more drug delivery into tumor. A physical model of intratumoral infusion catheters accurately predicts the observed drug delivery results. Our catheter design is retained in the liver (and does not migrate out with breathing motion), and it preferentially infuses the drug into tumor tissue (not intratumoral vessels).

Abstract 220: Cerebral Angioedema in a Patient with Refractory Hypertension and Intracerebral Hemorrhage

Introduction/Purpose There is emerging evidence to implicate bradykinin in the development of cerebral edema. In the periphery, its association to the development of angioedema is well known. However, the relationship of peripheral angioedema to the development of cerebral angioedema is not well established. Angioedema may occur in patients receiving antihypertensive medication, and alteplase for acute ischemic stroke (1), however, the concurrent involvement of cerebral vasculature is not well studied. Moreover, the connection with cerebral edema ‐ cytotoxic or vasogenic ‐ remains poorly understood. Here we present a patient with an intracerebral hemorrhage (ICH) in the setting of refractory hypertension, who developed angioedema, and ultimately fulminant cerebral edema. We aim to investigate whether angioedema may extend beyond a systemic response and into the cerebral vasculature, contributing to further neurological compromise. Materials/Methods A retrospective review was conducted for one patient. Data, including history, exam, imaging, and clinical interventions were analyzed. All identifiers were removed. Results A 51‐year‐old African American woman with a medically refractory hypertension on multiple home medications presented with aphasia, and a blood pressure of 220/110 mm Hg. An initial non contrast head CT revealed a 60‐cc left basal ganglia intracerebral hemorrhage. CTA of the head and neck were negative for an underlying structural abnormality. She required intubation soon after presentation due to obtundation. No interval re‐hemorrhage was noted on repeat head CT. A contrast enhanced MRI was also unrevealing. 48 hours later she was noted to have orolingual edema and an angiotensin converting enzyme inhibitor (ACEi) and diltiazem were discontinued. In the ensuing days, due to difficult to control hypertension despite being on multiple antihypertensives, an angiotensin II receptor blocker (ARB) was introduced. However, this was discontinued and reintroduced several days later only to be discontinued again due to orolingual edema. She also had a failed extubation attempt due to hypoxemia and stridor, and received FFP, decadron, and racemic epinephrine. 2 days later she developed bradycardia and had neurologic deterioration progressing from initial right hemiparesis to complete unresponsiveness on examination. A noncontrast head CT showed no interval re‐hemorrhage but did show new areas of hypodensity involving the bilateral occipital lobes, the brainstem, the left temporal lobe, and uncal herniation. Hypertonic saline was started, however the patient progressed to brain death. Conclusion This case highlights the potential link between systemic angioedema, and fulminant cerebral edema and rapid neurologic decline. Previous literature has described potentially parallel mechanisms behind peripheral angioedema and cerebral edema (2). Angioedema may also influence progression from vasogenic to cytotoxic cerebral edema. As vasogenic edema develops, the increased tissue pressure can lead to ischemia and exacerbate cytotoxic edema (3). The significance of posterior circulation involvement is noteworthy, as ischemic infarctions here can lead to neurological deficits and are associated with vasogenic edema due to blood‐brain barrier disruption, such as in posterior reversible encephalopathy syndrome (PRES). Further investigation is required to explore acute intracerebral effects of angioedema. Physicians should consider cerebral angioedema in patients with both peripheral angioedema and neurological deterioration.

Physiological Challenges and Adaptations in Competitive Freediving

Competitive freediving is associated with extreme physiologic challenges due to the effects of apnea, submersion in water, and increased ambient pressure. There has nevertheless been a continued progression of world records across freediving disciplines in recent years, with breath-hold times exceeding 10 minutes, and reaching diving depths beyond 200 meters of seawater. The main physiological determinants of breath-hold endurance are the available oxygen stores, i.e., intrapulmonary gas volume, inspired gas concentration, and rate of oxygen consumption. Other factors such as psychological and inherent factors contribute to the individual tolerance to an increasing respiratory stimulus with prolonged breath-hold duration. A freediving athlete must be able to tolerate apnea to stay underwater long enough to reach great distance or depth and resurface safely. Elite freedivers exhibit somewhat remarkable physiological adaptations such as a more pronounced diving-response and hypercapnia tolerance compared to non-divers, as well as metabolic and cerebrovascular adaptations. To reach great depths, elite freedivers employ a breathing technique called glossophyryngeal insufflation (GI) that is enlarging the ratio of total lung capacity to residual volume, thus, mitigating risk of lung squeeze and increasing intrapulmonary gas volume, and thereby enhancing available oxygen stores. Pulmonary anatomy and physiology could not be accounted to restrict the breath-hold diving depths achieved by competitive athletes. However, the acutely increased intrapulmonary pressure during GI is transmitted to the pulmonary vasculature, thereby eliciting a right ventricular pressure overload, and left ventricular dysfunction that may augment hypotension and syncope during glossopharyngeal insufflation. Due to extreme diffusion gradients between alveolar pN2 and N2 pressures in the body tissues at great depth, N2 will be forced into blood and body tissues during descent, elevating risk of N2 narcosis and decompression illness during deep dives. Breath-hold training and preparation have been shown to enhance breath-hold performance. This review highlights recent data on the profound cardiovascular, respiratory, and gas exchange effects that are observed in competitive freedivers, and discusses possible adaptations and risks for humans.

Fluid-filled lattices for responsive orthotic insoles

Abstract Orthotic insoles are essential for alleviating discomfort and preventing injuries in the foot caused by high peak pressures in the plantar tissue. Traditional orthotic insoles, often prescribed to address these issues, are designed based on the static foot shape and pressure measurements, lacking responsiveness to dynamic movements. This study explores the behaviour of fluid-filled lattices for improving the functionality of orthotic insoles, focusing on energy dissipation and pressure redistribution capabilities. Using numerical homogenisation, the research integrates hyperelastic and permeability models to simulate the behaviour of Solid–Liquid Composites. Experimental tests validated these models, examining the influence of fluid viscosity and structural variations on energy dissipation and pressure distribution. Results show that fluid-filled lattices provide enhanced energy dissipation and reduce peak pressures by evening out the pressure distribution compared to non-fluid-filled samples. These findings highlight the potential of fluid-filled lattices to improve the performance and comfort of orthotic insoles.

The biomechanics of turgor pressure

If you ever forget to water your houseplant, you may find its leaves getting soft and droopy - if you water it again in time, the leaves may stiffen, spring back up, and resist gravity. During this recovery, plant cells absorb water and build up an intracellular pressure, called turgor pressure, similar to inflating a balloon. Turgor pressure is an intrinsic component of plant physiology, and its biomechanical role as the 'hydroskeleton' is generally appreciated either statically in structural stability, like leaves resisting gravity, or dynamically in rapid motions, like Venus flytrap snapping, Mimosa closing, or stomatal opening. Slow but non-static processes like plant cell expansion also rely on turgor pressure, and it has been increasingly realized that turgor pressure and water fluxes in plant tissues play active roles in plant growth and morphogenesis. But where does turgor pressure come from, and how does it interact with other biomechanical properties of a plant cell? This primer aims to answer these questions by taking a brief tour from osmosis, to pressure vessel theory, then plant cell rheology. Although this primer is centered around intracellular pressure in plant cells, the biomechanical concepts are generally applicable to other organisms like bacteria and fungi, and even animal cells, which do not have cell walls, but are either embedded in stiff extracellular matrix (ECM) or are contracting (see the following section). To explain some of these concepts, we included a few equations, most of which are not hard to derive at all. We encourage readers to check the included examples, try for themselves, and look up derivations in suggested further reading materials.

The role of tissue oxygenation in obesity-related cardiometabolic complications

AbstractObesity is a complex, multifactorial, chronic disease that acts as a gateway to a range of other diseases. Evidence from recent studies suggests that changes in oxygen availability in the microenvironment of metabolic organs may exert an important role in the development of obesity-related cardiometabolic complications. In this review, we will first discuss results from observational and controlled laboratory studies that examined the relationship between reduced oxygen availability and obesity-related metabolic derangements. Next, the effects of alterations in oxygen partial pressure (pO2) in the adipose tissue, skeletal muscle and the liver microenvironment on physiological processes in these key metabolic organs will be addressed, and how this might relate to cardiometabolic complications. Since many obesity-related chronic diseases, including type 2 diabetes mellitus, cardiovascular diseases, chronic kidney disease, chronic obstructive pulmonary disease and obstructive sleep apnea, are characterized by changes in pO2 in the tissue microenvironment, a better understanding of the metabolic impact of altered tissue oxygenation can provide valuable insights into the complex interplay between environmental and biological factors involved in the pathophysiology of metabolic impairments. This may ultimately contribute to the development of novel strategies to prevent and treat obesity-related cardiometabolic diseases.

Abstract P452: Cell Populations and Transcriptomes Differ Across Blood Pressure and Sex in Perivascular Adipose Tissue: A Single-Nuclei RNA Sequencing Study

The perivascular adipose tissue (PVAT), fat that surrounds many blood vessels, is capable of modulating vascular tone through multiple modalities. Despite increasing research interest, PVAT remains less understood compared to other vascular layers. We hypothesized that the transcriptome and cell population of thoracic aorta PVAT (taPVAT) differ between hypertensive and normotensive rats. To test this hypothesis, we performed single-nucleus RNA-sequencing (snRNA-seq) on twenty-five taPVAT samples from male and female Dahl SS rats, fed either control (Con) chow or a high-fat diet (HFD) for 8 or 24 weeks. Mean arterial pressure (MAP) measurements showed elevated values in female rats fed a HFD for 24 weeks with a trend towards increasing blood pressure in male rats (Fig. 1a). Our analysis included at least three taPVAT samples per treatment group, resulting in 71,813 high-quality sequenced nuclei, representing eight major cell types (Fig. 1b) and twenty-eight cell sub-types. Within each cell type, the differences in population and gene expression across diet, diet duration, and sex were examined. The most substantial population proportion differences were observed across diet duration, with fewer differences noted across diet and sex (Fig. 1c). The total number of differentially expressed genes (DEGs) (adjusted p-value ≤ 0.05, |log 2 (fold change)| ≥ 1) across diet, diet duration, and sex were 191, 424, and 119, respectively. Interestingly, in the taPVAT from HFD fed rats, the gene Csmd1 (CUB and Sushi multiple domains 1) was consistently upregulated across nearly all cell types. Whereas Scd (stearoyl-CoA desaturase), which is involved in fatty acid biosynthesis, was frequently the most downregulated gene. Pathway enrichment analysis revealed that the DEGs related to the HFD were associated with a decrease in lipid and fatty acid biosynthetic processes. DEGs related to rats fed a HFD for twenty-four weeks versus eight weeks were linked to an enrichment in inflammatory response and extracellular matrix organization pathways, and in HFD fed male rats compared to females, there was enrichment for leukocyte aggregation and peptidyl-cysteine modification pathways. In conclusion, our findings help paint a more detailed picture of the molecular and cellular changes in taPVAT associated with hypertension.

Nonlinear Tissue Permeability Drives Tissue Pressure and Injection Distribution: A Computational Investigation of Subcutaneous Injections.

There is a significant opportunity to expand the understanding of subcutaneous injection mechanics with an aim to increase injectable volume while controlling tissue strain and associated subject pain. Computational modeling can evaluate the mechanics of subcutaneous injections as a supplement to experimental, animal and clinical studies. The objectives of this study are to (1) develop a computational model for subcutaneous injection in tissue, (2) investigate the influence anisotropic tissue permeability has on bolus formation, and (3) explore the effects that injection flow rate and viscosity have on injection flow and tissue strain. Poroelastic models with subsurface flow were implemented in finite element software (COMSOL, ABAQUS). Pore pressure and injectate distribution showed excellent agreement with experimental results when evaluated at multiple injection rates (20 ml/hr, 120 ml/hr and 360 ml/hr). Including the anisotropy of tissue permeability causes the injectate to preferentially spread horizontally, similar to experimentally observed bolus distributions. Cases are presented to provide additional insight into injection mechanics, including variations on the delivery rate, the injection volume, viscosity and the thickness of the subcutaneous layer. The results support the use of computational modeling as a valid tool for understanding tissue strains and injectate distributions for large volume injections.

Virtual Surgical Planning and Customized Subperiosteal Implant for Reconstruction of Maxillary Defect After Oncological Resection.

Reconstructing defects after jaw tumor removal is difficult because of the complex facial skeleton, which affects patient nutrition and self-confidence. Traditional methods like iliac bone or fibula grafts take a long time and may raise aesthetic issues. Advancements in computer-aided three-dimensional (3D) modeling allow precise surgical planning, leading to more symmetrical reconstructions. Moreover, the application of custom-designed prostheses, similar to joint prostheses used in joint surgery, offers promising outcomes, particularly in cases involving the removal of the ramus and temporomandibular joint. A 28-year-old female had a maxillectomy for maxillary myxoma, using 3D-printed implants for reconstruction and dental rehabilitation. "Computer-Aided Design" software optimized implant coordination, reducing soft tissue pressure. Postoperative permanent dentures were successful with few complications. Compared with traditional methods, 3D-printed titanium plates improve patient satisfaction and reduce treatment time, particularly with sufficient soft tissue thickness, offering aesthetic benefits and eliminating extra surgeries for effective defect treatment.

Diagnosis of Pressure Ulcer Stage Using On-Device AI

Pressure ulcers are serious healthcare concerns, especially for the elderly with reduced mobility. Severe pressure ulcers are accompanied by pain, degrading patients’ quality of life. Thus, speedy and accurate detection and classification of pressure ulcers are vital for timely treatment. The conventional visual examination method requires professional expertise for diagnosing pressure ulcer severity but it is difficult for the lay carer in domiciliary settings. In this study, we present a mobile healthcare platform incorporated with a light-weight deep learning model to exactly detect pressure ulcer regions and classify pressure ulcers into six severities such as stage 1–4, deep tissue pressure injury, and unstageable. YOLOv8 models were trained and tested using 2800 annotated pressure ulcer images. Among the five tested YOLOv8 models, the YOLOv8m model exhibited promising detection performance with overall classification accuracy of 84.6% and a mAP@50 value of 90.8%. The mobile application (app) was also developed applying the trained YOLOv8m model. The mobile app returned the diagnostic result within a short time (≒3 s). Accordingly, the proposed on-device AI app can contribute to early diagnosis and systematic management of pressure ulcers.

First successful ovarian cortex allotransplant to a Turner syndrome patient requiring immunosuppression: wide implications

ObjectiveTo determine whether we can safely and successfully transplant an ovary tissue allograft from a non-identical donor to her Turner syndrome sister. DesignTransplantation of cryopreserved ovary tissue, as well as fresh transplantation of ovarian tissue between identical twins, is now well established with numerous reported successful cases. However there have not yet been any ovary transplants between non-identical women requiring immunosuppression (ovary allotransplant). This could be a much more common indication for ovary tissue transplantation if safe and reliable immunosuppression were available. SubjectsA 20 year old amenorrheic woman with non-mosaic 45-XO Turner syndrome requested ovary tissue transplantation from her fertile 22 year old 46-XX sister. They were an HLA match but were ABO incompatible, a well known contra-indication to solid tissue or organ transplantation. The Turner syndrome sister strongly preferred to be able to become pregnant naturally without donor egg IVF, and to avoid HRT (hormone replacement therapy). In her religious group, that would also be important for finding a marital match. Despite the poor prognosis associated with ABO incompatibility, an ovary from her 22 year old non-identical fertile sister was transplanted to her employing the immunosuppression protocol now used for kidney transplant patients in our centers at Washington University and Johns Hopkins. Main Outcome MeasuresPost-operatively at 5 months she developed normal monthly menstrual ovarian function, and she became spontaneously pregnant with a normal baby girl. The relation between her post-op FSH and AMH levels continues to support the theory that tissue pressure controls primordial follicle recruitment. The fact that ABO incompatibility did not prevent success suggests that diffusion and not revascularization may be all that is required for successful long term ovarian cortex transplant survival with spontaneous pregnancy. ResultsOvary allotransplantation with safe immunosuppression allows natural conception, and also normal hormone function obviates the need for HRT. Orthotopic placement of the graft and surgical technique is critical for natural conception and a higher pregnancy rate. ConclusionAllotransplantation requiring safe immunosuppression, if successful, may be a much more commonly used indication for ovary transplantation in the future than frozen ovary grafts or grafts between identical twins.

Numerical simulation and mathematical modeling of biomechanical stress distribution in poroelastic tumor tissue via magnetic field and bio-ferro-fluid

Based on scientific evidence, it seems that bio-magnetic systems can change the process of cancer cell death by affecting the distribution of pressure and mechanical stress in the tumor tissue. Already most of the research has been done experimentally and few mathematical modeling and numerical simulations have been done to investigate the relationship between the magnetic parameters and the mechanical stress of the tumor tissue. This is despite the fact that in order to be able to make new equipment with the help of medical engineering methods, it is definitely necessary that the mathematics governing the problem and changes in the effective magnetic parameters (such as the shape of the magnetic source, magnetic flux density, magnetic source distance and ferro-fluid volume fraction) should be studied as much as possible. In this research, using numerical simulation and mathematical modeling, four common geometrical shapes (rectangular and circular) of the static magnetic field source were used to investigate the relationship between the change of the effective magnetic parameters and the mechanical stress created in the tumor tissue. The results of this research showed that when the magnetic flux density and ferro-fluid volume fraction and also the distance between the magnet and the tissue are kept constant, as well as without spending any extra energy, for a rectangular magnet, just by changing the way the source is placed on the tissue, the average biomechanical stress inside the tumor tissue causes a 25 % change. Also, for a circular magnet, just by doubling the radius of the magnet, the average biomechanical stress inside the tumor tissue causes a 73 % change.

Scoping Review of Wounds in Hospitalized Adults with COVID-19 Over the First Three Years of the Pandemic.

To synthesize the literature on skin failure and pressure injuries among hospitalized patients with COVID-19. An electronic literature search using relevant keywords and controlled vocabulary was conducted in March 2023 on MEDLINE/PubMed, Embase, and CINAHL. Manual citation searches of included articles and grey literature, including the Wound, Ostomy, and Continence Nurses Society website were performed. Articles published in English between 2020 and April 2023 were considered. Articles were included if they reported on COVID-19 positive hospitalized adults with wounds that were not present upon admission. A total of 31 articles met these criteria. Covidence was used to extract the data and was reviewed by multiple team members. Of the 31 studies, 27 reported new onset skin lesions during hospitalization. Wounds were classified as pressure injuries, skin failure, livedo racemosea and/or, retiform purpura, and associated with microvascular thrombosisthrombotic vasculopathy. Most pressure injuries were associated with prone position and affected patients often had multiple comorbidities including hypertension, diabetes mellitus, end-stage renal disease, heart disease, and COPD. Four articles highlighted an increased risk of new onset wounds, and three emphasized the importance of distinguishing deep tissue pressure injuries from ischemic-related lesions in patients with COVID-19. The evidence suggests an increased risk of ischemic lesions and pressure injuries (PI) in patients with COVID-19 infection. This phenomenon may have inflated the numbers of PI during the pandemic and adversely affected nursing quality measures in acute care environments.

Blocking Sigmar1 exacerbates methamphetamine-induced hypertension

AimMethamphetamine (METH) chronic exposure is an important risk factor for hypertension development. However, the mechanisms behind METH-induced hypertension remain unclear. Therefore, we aimed to reveal the potential mechanisms underlying METH-induced hypertension. Methods and resultsWe structured the mouse hypertension model by METH, and observed that METH-treated mice have presented vascular remodeling (large-and small-size arteries) with collagen deposit around the vessel and increasing blood pressure (BP) and Sigma1 receptor (Sigmar1) in vascular tissue. We hypothesized that Sigmar1 is crucial in METH-induced hypertension and vascular remodeling. Sigmar1 knockout (KO) mice and antagonist (BD1047) pretreated mice exposed to METH for six-week showed higher BP and more collagen deposited around vessels than wild-type (WT) mice exposed to METH for six-week, in contrast, mice pretreated with Sigmar1 agonist (PRE-084) had unchanged BP and perivascular collagen despite the six-week METH exposure. Furthermore, we found that METH exposure induced vascular smooth muscle cells (VSMCs) and mesenchymal stem cells to differentiate into the myofibroblast-like cell and secrete collagen into surrounding vessels. Mechanically, Sigmar1 can suppress the COL1A1 expression by blocking the classical fibrotic TGF-β/Smad2/3 signaling pathway in METH-exposed VSMCs and mesenchymal stem cells. ConclusionOur results suggest that Sigmar1 is involved in METH-induced hypertension and vascular fibrosis by blocking the activation of the TGF-β/Smad2/3 signaling pathway. Accordingly, Sigmar1 may be a novel therapeutic target for METH-induced hypertension and vascular fibrosis.

Double Reinforcing Strategy with Perpendicular Plate of Ethmoid in Asian Secondary Unilateral Cleft Rhinoplasty: A Finite Element Analysis.

Deviation and asymmetry relapse after secondary unilateral cleft rhinoplasty with septal extension graft is a common yet serious problem especially among Asian patients. Therefore, finding an effective approach to reduce deformity relapse remains a great challenge to plastic surgeons. In this study, authors established finite element models to simulate different nasal cartilage-corrected options and different reinforcing strategies in secondary unilateral cleft rhinoplasty. A load of 0.01N was given to the nasal tip to simulate the soft tissue pressure, while two loads of 0.5N were separately given to the anterior and posterior part of the septal extension graft to simulate the rhinoplasty condition. Maximum deformations were evaluated to make stability judgments. The maximum deformation of different cartilage correction models in ascending order was: UCL deformity with septum correction, normal nasal cartilage, UCL nasal deformity, and UCL nasal deformity with lower lateral cartilage correction. When applied L-strut reinforcement graft was harvested from the perpendicular plate of the ethmoid bone, the maximum deformation of the models decreased significantly, and strong fixation of the septum could further enhance this decreasing effect. Correcting the septum and lower lateral cartilage together could improve the structural stability and symmetry in secondary unilateral cleft rhinoplasty. To keep the corrected septum stable and thus reduce deformity relapse, reinforcing the L-strut with perpendicular plate of ethmoid graft while strongly anchoring the septal cartilage to the anterior nasal spine was proved to be effective in both finite element analysis and clinical observation. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .