Venous-plexus-associated lymphoid hubs support meningeal humoral immunity.

There is increasing interest in how immune cells in the meninges-the membranes that surround the brain and spinal cord-contribute to homeostasis and disease in the central nervous system1,2. The outer layer of the meninges, the dura mater, has recently been described to contain both innate and adaptive immune cells, and functions as a site for B cell development3-6. Here we identify organized lymphoid structures that protect fenestrated vasculature in the dura mater. The most elaborate of these dural-associated lymphoid tissues (DALT) surrounded the rostral-rhinal confluence of the sinuses and included lymphatic vessels. We termed this structure, which interfaces with the skull bone marrow and a comparable venous plexus at the skull base, the rostral-rhinal venolymphatic hub. Immune aggregates were present in DALT during homeostasis and expanded with age or after challenge with systemic or nasal antigens. DALT contain germinal centre B cells and support the generation of somatically mutated, antibody-producing cells in response to a nasal pathogen challenge. Inhibition of lymphocyte entry into the rostral-rhinal hub at the time of nasal viral challenge abrogated the generation of germinal centre B cells and class-switched plasma cells, as did perturbation of B-T cell interactions. These data demonstrate a lymphoid structure around vasculature in the dura mater that can sample antigens and rapidly support humoral immune responses after local pathogen challenge.

Bridging vascular physiology to vascular medicine: an integrative laboratory class.

Vascular diseases of the legs are highly prevalent and constitute an important part of medical curricula. The understanding of these diseases relies on strongly interwoven aspects of vascular physiology and vascular medicine. We aimed to connect these within a horizontally integrated laboratory class on vascular physiology of the leg that was designed in cooperation between the departments of physiology and vascular surgery. Conceptually, we applied examination techniques of vascular medicine to visualize physiological parameters that are altered by the most frequent diseases. This facilitates integrative discussions on malfunctions, trains diagnostic skills, and bridges to vascular medicine. In four experiments, we use oscillometry and impedance venous occlusion plethysmography to address key aspects of the arterial and venous system of the legs: 1) arterial pulse wave, 2) arterial systolic blood pressure, 3) venous capacitance and venous outflow, and 4) reactive hyperemia. After the experiments, physiological vascular function, the associated diseases, their impact on the recorded parameters, and diagnostic options are discussed. To allow reproduction, we describe the course structure and the experimental setup in detail. We present the experimental data of a cohort of medical students and document learning success and student satisfaction. All experiments were feasible and provided robust data on physiologically and clinically relevant vascular functions. The activity was perceived positively by the students and led to a substantial improvement of knowledge. With this work, we offer a template for reproduction or variation of a proven concept of horizontally integrated teaching of vascular physiology of the leg.NEW & NOTEWORTHY This article presents an integrative laboratory class on vascular physiology bridging to vascular medicine. The four experiments rely on oscillometry and venous occlusion plethysmography. We describe in detail this new class regarding structure, experimental setup, and experimental procedure, and we give insight into the applied materials. Moreover, we present the experimental data of 74 students and a quantitative evaluation of the students' learning success and acceptance.

A randomized controlled trial of the effect of postoperative hand exercise training on arteriovenous fistula maturation in patients with chronic kidney disease.

OBJECTIVE: Immature arteriovenous fistula (AVF) is a critical problem in patients with chronic kidney disease (CKD) after creation. Exercise with 30% maximum voluntary contraction (MVC) encourages vascular functions in other populations. It is unknown which exercise type is superior on maturation in the CKD population. We compare effects of isometric (ISM) and isotonic (IST) hand exercise training, both at 30% MVC, on AVF maturation and grip strength in patients with CKD. METHODS: Fifty patients with CKD were randomized into the ISM program or IST program (25 per group). Each group performed exercise program at intensity of 30% MVC every day for 10 weeks. Cephalic vein (CV) and brachial artery diameters, brachial blood flows, and grip strength were measured at weeks 0, 2, 6, and 10 of the program. The number of patients meeting clinical and ultrasound maturation were evaluated at weeks 2, 6, and 10. RESULTS: At weeks 6 and 10 of the programs, the ISM group had greater CV diameters (week 6, 7.1 ± 1.2 vs 6.2 ± 1.0 mm; week 10, 7.1 ± 1.0 vs 6.2 ± 1.1 mm) than the IST group. Compared with the IST group, the ISM group had a higher number of patients meeting ultrasound maturation at weeks 2 (IST/ISM, 8/2), 6 (IST/ISM, 16/8), and 10 (IST/ISM, 21/12), and clinical maturation at week 10 (IST/ISM, 25/18). No adverse events were observed throughout the study. CONCLUSIONS: At 30% MVC, ISM is more effective at promoting increases in CV diameter and maturation than IST. Both exercise types are feasible and safe for patients with CKD after AVF creation.

Individualized tissue-engineered veins as vascular grafts: A proof of concept study in pig.

Personalized tissue engineered vascular grafts are a promising advanced therapy medicinal product alternative to autologous or synthetic vascular grafts utilized in blood vessel bypass or replacement surgery. We hypothesized that an individualized tissue engineered vein (P-TEV) would make the body recognize the transplanted blood vessel as autologous, decrease the risk of rejection and thereby avoid lifelong treatment with immune suppressant medication as is standard with allogenic organ transplantation. To individualize blood vessels, we decellularized vena cava from six deceased donor pigs and tested them for cellular removal and histological integrity. A solution with peripheral blood from the recipient pigs was used for individualized reconditioning in a perfusion bioreactor for seven days prior to transplantation. To evaluate safety and functionality of the individualized vascular graft in vivo, we transplanted reconditioned porcine vena cava into six pigs and analyzed histology and patency of the graft at different time points, with three pigs at the final endpoint 4-5 weeks after surgery. Our results showed that the P-TEV was fully patent in all animals, did not induce any occlusion or stenosis formation and we did not find any signs of rejection. The P-TEV showed rapid recellularization in vivo with the luminal surface covered with endothelial cells. In summary, the results indicate that P-TEV is functional and have potential for use as clinical transplant grafts.

Reverse blood flow in cervicofacial veins after venous ligations: Potential implications in microsurgery.

INTRODUCTION: The consequences on the cervicofacial venous circulation of major cervicofacial vein ligations are poorly known. We aimed to highlight by using Doppler Ultrasound flow differences in the cervicofacial venous network in the case of unilateral or bilateral ligation of main venous collector trunks (external jugular vein [EJV] and internal jugular vein [IJV]) METHODS: A Doppler ultrasound was performed on 10 healthy volunteers, 8 patients with previous bilateral ligation of the EJV, 8 with a unilateral ligation of the EJV, and 8 with a unilateral ligation of the EJV and IJV, after modified radical neck dissection. The diameter, the flow direction and the peak systolic velocity (PSV) of the superficial temporal vein, the facial vein (FV) and the IJV were measured. RESULTS: Healthy patients had a similar right and left PSV for all the veins studied, with always antegrade flows. Patients with previous ligations had some significant right/left differences and retrograde flows. CONCLUSION: A redistribution of venous blood flow on the contralateral side of the face and neck seems to take place in the case of unilateral ligation of the EJV and/or IJV. Retrograde flows are sometimes observed in the case of previous ligation of the EJV and/or IJV and might compromise the success of venous microanastomoses.

Activation of EphrinB2 Signaling Promotes Adaptive Venous Remodeling in Murine Arteriovenous Fistulae.

BACKGROUND: Arteriovenous fistulae (AVF) are the preferred mode of vascular access for hemodialysis. Before use, AVF remodel by thickening and dilating to achieve a functional conduit via an adaptive process characterized by expression of molecular markers characteristic of both venous and arterial identity. Although signaling via EphB4, a determinant of venous identity, mediates AVF maturation, the role of its counterpart EphrinB2, a determinant of arterial identity, remains unclear. We hypothesize that EphrinB2 signaling is active during AVF maturation and may be a mechanism of venous remodeling. METHODS: Aortocaval fistulae were created or sham laparotomy was performed in C57Bl/6 mice, and specimens were examined on Days 7 or 21. EphrinB2 reverse signaling was activated with EphB4-Fc applied periadventitially in vivo and in endothelial cell culture medium in vitro. Downstream signaling was assessed using immunoblotting and immunofluorescence. RESULTS: Venous remodeling during AVF maturation was characterized by increased expression of EphrinB2 as well as Akt1, extracellular signal-regulated kinases 1/2 (ERK1/2), and p38. Activation of EphrinB2 with EphB4-Fc increased phosphorylation of EphrinB2, endothelial nitric oxide synthase, Akt1, ERK1/2, and p38 and was associated with increased diameter and wall thickness in the AVF. Both mouse and human endothelial cells treated with EphB4-Fc increased phosphorylation of EphrinB2, endothelial nitric oxide synthase, Akt1, ERK1/2, and p38 and increased endothelial cell tube formation and migration. CONCLUSIONS: Activation of EphrinB2 signaling by EphB4-Fc was associated with adaptive venous remodeling in vivo while activating endothelial cell function in vitro. Regulation of EphrinB2 signaling may be a new strategy to improve AVF maturation and patency.

Surgical anatomy of the pelvis for total pelvic exenteration with distal sacrectomy: a cadaveric study.

PURPOSE: Intraoperative bleeding from the pelvic venous structures is one of the most serious complications of total pelvic exenteration with distal sacrectomy. The purpose of this study was to investigate the topographic anatomy of these veins and the potential source of the bleeding in cadaver dissections. METHODS: We dissected seven cadavers, focusing on the veins in the surgical resection line for total pelvic exenteration with distal sacrectomy. RESULTS: The presacral venous plexus and the dorsal vein complex are thin-walled, plexiform, and situated on the line of resection. The internal iliac vein receives blood from the pelvic viscera and the perineal and the gluteal regions and then crosses the line of resection as a high-flow venous system. It has abundant communications with the presacral venous plexus and the dorsal vein complex. CONCLUSION: The anatomical features of the presacral venous plexus, the dorsal vein complex, and the internal iliac vein make them highly potential sources of bleeding. Surgical management strategies must consider the anatomy and hemodynamics of these veins carefully to perform this procedure safely.

Diagnostic yield of capillary compared to venous glucose in the diagnosis of hypoglycorrhachia in children: A prospective, observational study.

INTRODUCTION: The ratio of cerebrospinal fluid (CSF) glucose and blood glucose is of major relevance, conducting to the diagnosis of hypoglycorrhachia, which is a sign of neuroinfection, as well as a number of neurological diseases of genetic or neoplastic etiology. Glucose in capillary sample (glucometry) is a low cost, readily available technique, as compared to venous glucose. This study aims to compare glucometry to venous glucose in the diagnosis of hypoglycorrhachia in pediatric population. METHODS: Prospective cross-sectional study based on data obtained from lumbar punctures in the period from February 2017 to January 2019 in a specialized pediatric institution in Colombia. RESULTS: 97 patients were analyzed, aged 1 month to 17 years old, mean 7.67 years, 52 (53.61%) were female. 26 (26.8%) were diagnosed with hypoglycorrhachia. Pearson correlation coefficient for absolute venous and capillary glucose was 0.54, and 0.55 for the ratios of CSF glucose/venous glucose and CSF glucose/glucometry, which support a linear correlation between the variables in both, absolute values and ratios. Intraclass correlation coefficient was calculated for both, the venous glucose and glucometry ratios, which was 0.52, revealing a moderate agreement among the tests. Sensitivity and specificity of CSF glucose/glucometry, as compared to gold standard are 73.1% and 60.6% respectively; whereas predictive positive value (PPV) and negative predictive value (NPV), were 40.4% and 86.0%. CONCLUSION: Glucometry cannot replace the glucose in venous sample in the diagnosis of hypoglycorrhachia in children.

Novel noninvasive estimation of mixed venous oxygen saturation by echocardiography and expired gas analysis.

Mixed venous oxygen (O2) saturation ([Formula: see text]) is an important measure for evaluating the sufficiency of cardiac output (CO) relative to whole body O2 consumption (V̇o2), while clinical use is limited to the required invasive catheterization. According to Fick's equation, V̇o2 (mL/min) = CO (L/min) × Hb (g/dL) × 1.36 (mL/g) × ([Formula: see text] - [Formula: see text])/10 (Hb = hemoglobin concentration, [Formula: see text] = arterial blood O2 saturation). Because V̇o2, CO, Hb, and [Formula: see text] can be measured noninvasively with expired gas analysis, echocardiography, a simple blood test, and percutaneous O2 saturation, respectively, [Formula: see text] can be calculated noninvasively. We hypothesized that noninvasively calculated [Formula: see text] shows a significant correlation and agrees well with invasively measured [Formula: see text]. In 47 patients (29 men; mean age, 70 ± 12 yr) who underwent right heart catheterization, [Formula: see text] was directly measured by sampling pulmonary artery blood. Noninvasively calculated [Formula: see text] was also obtained by the method described above. The calculated [Formula: see text] was significantly correlated with the measured [Formula: see text] (r = 0.79, P < 0.001) and was significantly smaller than the measured [Formula: see text] (70 ± 5.1 vs. 72.1 ± 4.9%, P < 0.001). Bias at [Formula: see text] was -2.2% (95% confidence interval, -3.2 to -1.1%) with limits of agreement from -9.5 to 5.2%, demonstrating acceptable agreement. The optimal cutoff value of calculated [Formula: see text] was 69% for reduced measured [Formula: see text] < 70% with an area under the curve of 0.94. Reduced calculated [Formula: see text] < 69% indicated a sensitivity of 92.9% and a specificity of 90.9% for reduced measured [Formula: see text] < 70%. Noninvasive [Formula: see text] calculated from echocardiography, expired gas analysis, percutaneous arterial blood O2 saturation, and hemoglobin level significantly correlated and agreed well with direct [Formula: see text] measured by catheterization. This novel method allows for practical evaluation of [Formula: see text] to assess the sufficiency of CO according to whole body metabolism.NEW & NOTEWORTHY Clinical use of mixed venous oxygen saturation ([Formula: see text]) is limited to the required invasive procedure. With Fick's equation, expired gas analysis, echocardiography, simple blood tests, and percutaneous oxygen saturation, [Formula: see text] can be calculated noninvasively. We hypothesized that noninvasively calculated [Formula: see text] shows a significant correlation and agrees well with invasively measured [Formula: see text]. The present study examined the relationship between measured [Formula: see text] and calculated [Formula: see text] in patients who underwent right heart catheterization and demonstrated acceptable agreement. This novel method can expand the indication of evaluating [Formula: see text].

Non-Invasive Venous waveform Analysis (NIVA) for volume assessment during complex cranial vault reconstruction: A proof-of-concept study in children.

BACKGROUND: Non-Invasive Venous waveform Analysis (NIVA) is novel technology that captures and analyzes changes in venous waveforms from a piezoelectric sensor on the wrist for hemodynamic volume assessment. Complex cranial vault reconstruction is performed in children with craniosynostosis and is associated with extensive blood loss, potential life-threatening risks, and significant morbidity. In this preliminary study, we hypothesized that NIVA will provide a reliable, non-invasive, quantitative assessment of intravascular volume changes in children undergoing complex cranial vault reconstruction. OBJECTIVE: To present proof-of-concept results of a novel technology in the pediatric population. METHODS: The NIVA prototype was placed on each subject's wrist, and venous waveforms were collected intraoperatively. Estimated blood loss and fluid/blood product administration were recorded in real time. Venous waveforms were analyzed into a NIVA value and then correlated, along with mean arterial pressure (MAP), to volume changes. Concordance was quantified to determine if the direction of change in volume was similar to the direction of change in MAP or change in NIVA. RESULTS: Of 18 patients enrolled, 14 had usable venous waveforms, and there was a significant correlation between change in NIVA value and change in volume. Change in MAP did not correlate with change in volume. The concordance between change in MAP and change in volume was less than the concordance between change in NIVA and change in volume. CONCLUSION: NIVA values correlate more closely to intravascular volume changes in pediatric craniofacial patients than MAP. This initial study suggests that NIVA is a potential safe, reliable, non-invasive quantitative method of measuring intravascular volume changes for children undergoing surgery.

Collector Channels: Role and Evaluation in Schlemm's Canal Surgery.

OBJECTIVES: 1) To elucidate the role of collector channels in the aqueous humor outflow pathway 2) To suggest anatomic and functional methods of imaging collector channels in-vitro and in-vivo and 3) To discuss the role of such imaging modalities in the surgical management of glaucoma. METHODS: A thorough literature search was conducted on databases for studies published in English regarding the available methods to determine the role of collecting channels in normal and glaucomatous patients and to assess their patency. RESULTS: Intraocular pressure (IOP) exists as a balance between aqueous humor production and aqueous humor outflow. Collector channels are an essential anatomical constituent of the distal portion of the conventional aqueous humor outflow pathway. There are different surgical options for glaucoma management and with the recent advances in Schlemm's canal-based surgeries, collector channel's patency became a key factor in determining the optimum management for the glaucomatous eye. The advent of anatomic imaging methods has improved the ability to visualize collector channel morphology in-vitro, including swept-source optical coherence tomography (SS-OCT), spectral domain optical coherence tomography (SD-OCT), micro-computed tomography (micro CT), new immunohistochemistry techniques and scanning electron microscopy. The recent advent of real-time assessment of collector channel patency (including evaluation of episcleral venous outflow, observation of episcleral venous fluid wave, and tracer studies utilizing fluorescein, indocyanine green, and trypan blue) has been validated by the aforementioned anatomic imaging modalities. CONCLUSIONS: New modalities of in-vitro and in-vivo studies of collector channels provide promise to aid in the assessment of collector channel patency and individualization of surgical management for glaucoma patients.

Conservation of both hematocrit and liver regeneration in hepatectomies: a vascular occlusion approach in rats.

BACKGROUND: Hepatectomies promote considerable amount of blood loss and the need to administrate blood products, which are directly linked to higher morbimortality rates. The blood-conserving hepatectomy (BCH) is a modification of the selective vascular occlusion technique. It could be a surgical maneuver in order to avoid or to reduce the blood products utilization in the perioperative period. AIM: To evaluate in rats the BCH effects on the hematocrit (HT) variation, hemoglobin serum concentration (HB), and on liver regeneration. METHODS: Twelve Wistar rats were divided into two groups: control (n=6) and intervention (n=6). The ones in the control group had their livers partially removed according to the Higgins and Anderson technique, while the rats in the treatment group were submitted to BCH technique. HT and HB levels were measured at day D0, D1 and D7. The rate between the liver and rat weights was calculated in D0 and D7. Liver regeneration was quantitatively and qualitatively evaluated. RESULTS: The HT and HB levels were lower in the control group as of D1 onwards, reaching an 18% gap at D7 (p=0.01 and p=0.008, respectively); BCH resulted in the preservation of HT and HB levels to the intervention group rats. BCH did not alter liver regeneration in rats. CONCLUSION: The BCH led to beneficial effects over the postoperative HT and serum HB levels with no setbacks to liver regeneration. These data are the necessary proof of evidence for translational research into the surgical practice. A) Unresected liver; B) liver appearance after the partial hepatectomy (1=vena cava; 2=portal vein; 3=hepatic vein; 4=biliary drainage; 5=hepatic artery).

Urinary I-FABP, L-FABP, TFF-3, and SAA Can Diagnose and Predict the Disease Course in Necrotizing Enterocolitis at the Early Stage of Disease.

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease affecting mainly preterm newborns. It is characterized by unexpected onset and rapid progression with specific diagnostic signs as pneumatosis intestinalis or gas in the portal vein appearing later in the course of the disease. Therefore, we analyzed diagnostic and prognostic potential of the markers of early NEC pathogenesis, such as excessive inflammatory response (serum amyloid A (SAA)) and gut epithelium damage (intestinal and liver fatty acid-binding protein (I-FABP and L-FABP, respectively) and trefoil factor-3 (TFF-3)). We used ELISA to analyze these biomarkers in the urine of patients with suspected NEC, either spontaneous or surgery-related, or in infants without gut surgery (controls). Next, we compared their levels with the type of the disease (NEC or sepsis) and its severity. Already at the time of NEC suspicion, infants who developed NEC had significantly higher levels of all tested biomarkers than controls and higher levels of I-FABP and L-FABP than those who will later develop sepsis. Infants who will develop surgery-related NEC had higher levels of I-FABP and L-FABP than those who will develop sepsis already during the first 6 hours after the abdominal surgery. I-FABP was able to discriminate between infants who will develop NEC or sepsis and the SAA was able to discriminate between medical and surgical NEC. Moreover, the combination of TFF-3 with I-FABP and SAA could predict pneumatosis intestinalis, and the combination of I-FABP, L-FABP, and SAA could predict gas in the portal vein or long-term hospitalization and low SAA predicts early full enteral feeding. Thus, these biomarkers may be useful not only in the early, noninvasive diagnostics but also in the subsequent NEC management.

Annexin A3 is necessary for parallel artery-vein alignment in the mouse retina.

BACKGROUND: Annexin A3 (Anxa3) is a member of the calcium-regulated, cell membrane-binding family of annexin proteins. We previously confirmed that Anxa3 is expressed in the endothelial lineage in vertebrates and that loss of anxa3 in Xenopus laevis leads to embryonic blood vessel defects. However, the biological function of Anxa3 in mammals is completely unknown. In order to investigate Anxa3 vascular function in mammals, we generated an endothelial cell-specific Anxa3 conditional knockout mouse model (Anxa3f/f ;Tie2-Cre). RESULTS: Anxa3f/f ;Tie2-Cre mice are born at Mendelian ratios and display morphologically normal blood vessels during development. However, loss of Anxa3 leads to artery-vein (AV) misalignment characterized by atypical AV crossovers in the postnatal and adult retina. CONCLUSIONS: Anxa3 is not essential for embryonic blood vessel formation but is required for proper parallel AV alignment in the murine retina. AV crossovers associated with Anxa3f/f ;Tie2-Cre mice are similar to AV intersections observed in patients with branch retinal vein occlusion (BRVO), although we did not observe occluded vessels. This new Anxa3 mouse model may provide a basis for understanding AV crossover formation associated with BRVO.

Can smiling influence the blood flow in the facial vein?-An experimental study.

BACKGROUND: The understanding of functional facial anatomy and the interplay between facial structures is crucial for safe and effective minimally invasive and cosmetic surgical procedures. AIM: In this experimental study, we investigate the hypothesis that smiling can alter the blood flow in the angular/facial vein. MATERIALS AND METHODS: Twenty-six observations from 15 healthy volunteers (6 men, 9 women) with a mean age of 50.53 ± 13.27 (range: 24-66) were obtained. Doppler ultrasound imaging of the infraorbital segment of the angular vein (cranial to the zygomaticus major muscle) was performed and the venous flow was measured in a smiling and a resting, nonsmiling facial position. RESULTS: A statistically significant change in venous blood flow was detected upon smiling: a reduction in flow from 6.12 ± 3.0 cm/s to 0.52 ± 1.3 cm/s (P = .001). After three seconds, 80.8% of the observations had a blood flow of 0.0 cm/s. Increasing age was significantly correlated with a persistent blood flow during smiling (rp  = .469; P = .016). No differences between gender and sides of the face were observed. CONCLUSION: The results of this experimental study reveal that smiling can significantly reduce the venous flow in the angular/facial vein. Contraction of the zygomaticus major muscle compresses the vein against the underlying maxilla. Both minimally invasive and surgical procedures that alter the SMAS, the periocular musculature or the deep midfacial fat compartments might affect angular/facial venous flow.

Conservation of both hematocrit and liver regeneration in hepatectomies: a vascular occlusion approach in rats / Hepatectomia hemoconservadora no rato: preservação do hematócrito e da regeneração hepática

ABSTRACT Background: Hepatectomies promote considerable amount of blood loss and the need to administrate blood products, which are directly linked to higher morbimortality rates. The blood-conserving hepatectomy (BCH) is a modification of the selective vascular occlusion technique. It could be a surgical maneuver in order to avoid or to reduce the blood products utilization in the perioperative period. Aim: To evaluate in rats the BCH effects on the hematocrit (HT) variation, hemoglobin serum concentration (HB), and on liver regeneration. Methods: Twelve Wistar rats were divided into two groups: control (n=6) and intervention (n=6). The ones in the control group had their livers partially removed according to the Higgins and Anderson technique, while the rats in the treatment group were submitted to BCH technique. HT and HB levels were measured at day D0, D1 and D7. The rate between the liver and rat weights was calculated in D0 and D7. Liver regeneration was quantitatively and qualitatively evaluated. Results: The HT and HB levels were lower in the control group as of D1 onwards, reaching an 18% gap at D7 (p=0.01 and p=0.008, respectively); BCH resulted in the preservation of HT and HB levels to the intervention group rats. BCH did not alter liver regeneration in rats. Conclusion: The BCH led to beneficial effects over the postoperative HT and serum HB levels with no setbacks to liver regeneration. These data are the necessary proof of evidence for translational research into the surgical practice.

RESUMO Racional: As hepatectomias compreendem considerável perda sanguínea e utilização de hemoderivados, o que diretamente estão relacionados com maior morbimortalidade. A hepatectomia hemoconservadora (HH) é modificação da técnica de oclusão vascular seletiva em hepatectomia. Ela pode ser alternativa cirúrgica para evitar ou diminuir o uso de hemoderivados no perioperatório. Objetivo: Avaliar os efeitos da HH sobre o volume globular (VG), concentração de hemoglobina (HB) e sobre a regeneração hepática em ratos. Métodos: Dois grupos de ratos Wistar foram constituídos: controle (n=6) e intervenção (n=6). Os do grupo controle foram submetidos à hepatectomia parcial de Higgins e Anderson e os do grupo Intervenção à HH. VG e HB foram medidos nos dias D0, D1 e D7. A relação peso do fígado/peso do rato foi calculada em D0 e D7. A regeneração hepática foi analisada qualitativamente e quantitativamente. Resultados: Houve diminuição dos níveis de VG e HB nos ratos do grupo controle a partir de D1, atingindo decréscimo de 18% em D7 (p=0,01 e p=0,008 respectivamente); a HH permitiu a manutenção dos níveis de VG e HB nos ratos do grupo intervenção. A HH não alterou a regeneração hepática. Conclusão: HH resultou em níveis maiores de VG e HB pós-operatórios sem alterar a regeneração hepática. Pode-se considerar estes dados como a prova necessária para a translação à pesquisa clinicocirúrgica.

Dynamic vessel adaptation in synthetic arteriovenous networks.

Blood vessel networks of living organisms continuously adapt their structure under the influence of hemodynamic and metabolic stimuli. For a fixed vessel arrangement, blood flow characteristics still depend crucially on the morphology of each vessel. Vessel diameters adapt dynamically according to internal and external stimuli: Endothelial wall shear stress, intravascular pressure, flow-dependent metabolic stimuli, and electrical stimuli conducted from distal to proximal segments along vascular walls. Pries et al. formulated a theoretical model involving these four local stimuli to simulate long-term changes of vessel diameters during structural adaption of microvascular networks. Here we apply this vessel adaptation algorithm to synthetic arteriovenous blood vessel networks generated by our simulation framework "Tumorcode". We fixed the free model parameters by an optimization method combined with the requirement of homogeneous flow in the capillary bed. We find that the local blood volume, surface to volume ratio and branching ratio differs from networks with radii fulfilling Murray's law exactly to networks with radii obtained by the adaptation algorithm although their relation is close to Murray's law.

A Case of a Large Cephalic Vein Aneurysm.

Vein aneurysms represent a rare clinical entity with a wide range of clinical symptoms. We present a case of a 67-year-old male who presented with a large, bluish, easily compressible, soft tissue mass in the lateral side of his forearm, which was mildly tender and it had been worsening during the last year. A color duplex ultrasound revealed local venous dilatation of the cephalic vein, measuring 6.3 × 3.2 cm. The patient was operated under local anesthesia and the lesion was removed. Histology showed thinning of the inner and middle layers of the cephalic vein and incipient replacement of the outer layer by acellular fibrous tissue with progressive decrease of elastic, smooth muscle and collagen fibers of the inner and middle layers, compatible with an aneurysm of the cephalic vein. Large cephalic vein aneurysms might cause nerve compression and require surgical removal before permanent neurological defect occurs.

Plexos venosos plantares: Implicancia clínico-quirúrgica / Venous plantar plexus pump: Clinical and surgical implication

En 1888, Lejars describió la suela venosa que lleva su nombre. Se trata de un entramado venoso dispuesto en la planta del pie, que involucra los bordes medial y lateral. Dicho autor la describió en forma indirecta, por transparencia, a través de una inyección de resina y negro humo. En esta actualización, se ofrece una descripción directa y detallada de la suela venosa de Lejars mediante inyección con látex (Butaclor), que permitió identificar claramente dos planos. Las disecciones se efectuaron en pies de adultos y en fetos a término. Este trabajo de investigación anatómica pretende demostrar en forma objetiva la existencia de una malla venosa única que resulta imprescindible para la función hidráulica, sobre todo, del talón posterior del pie como centro de apoyo y marcha. Asimismo, se describen las incisiones quirúrgicas más idóneas para el abordaje de afecciones que comprometen dicho entramado. Nivel de Evidencia: IV

In 1888, Lejars described the vein sole that bears his name. It is a venous network arranged on the sole of the foot, which involves the medial and lateral borders. Said author described it indirectly, by transparency, through an injection of resin and black smoke. In this update, a direct and detailed description of the Lejars venous sole is offered by injection with latex (Butachlor), which clearly identified two planes. The dissections were performed on adult feet and full-term fetuses. This paper, based on anatomical research aims to objectively demonstrate the existence of a single venous mesh that is essential for hydraulic function, especially the posterior heel of the foot as a support and walking center. Likewise, the most appropriate surgical incisions are described for the treatment of conditions that compromise this network. Level of Evidence: IV