Several mechanisms have been proposed to explain the process of vein pattern formation in plant tissues. The most widely accepted amongst biologists is the canalization hypothesis, derived from pea root and stem experiments. According to this hypothesis, a signal, thought to be the phytohormone auxin, is transported polarly from cell to cell from the shoot to the root and is canalized progressively into narrow channels of high auxin fluxes that later differentiate to become vascular tissue. In this project, we set out to test whether auxin canalization drives vein pattern formation, using Arabidopsis thaliana mutants with increased auxin transport (max4-1, max3-9, max2-1 and max1-1). We predicted that the mutants would have distinct vein patterns and especially different angles between the primary and secondary veins, compared to the wild type. First rosette leaves of 15 plants per genotype were harvested for analysis each day from 7 to 17 days after sowing, giving a total of eight hundred twenty-five leaf samples to analyze. Venation patterns were extracted and analyzed using custom-made software written with Matlab. Overall, compared with the wild type, mutants with the highest auxin transport (max4-1 and max3-9) had different vein patterns at early developmental stages, confirming a role for auxin transport in vein patterning. However, veins of mutants and wild type connected at similar angles, which is not consistent with the auxin canalization hypothesis, as originally formulated.

Several mechanisms have been proposed to explain the process of vein pattern formation in plant tissues. The most widely accepted amongst biologists is the canalization hypothesis, derived from pea root and stem experiments. According to this hypothesis, a signal, thought to be the phytohormone auxin, is transported polarly from cell to cell from the shoot to the root and is canalized progressively into narrow channels of high auxin fluxes that later differentiate to become vascular tissue. In this project, we set out to test whether auxin canalization drives vein pattern formation, using Arabidopsis thaliana mutants with increased auxin transport (max4-1, max3-9, max2-1 and max1-1). We predicted that the mutants would have distinct vein patterns and especially different angles between the primary and secondary veins, compared to the wild type. First rosette leaves of 15 plants per genotype were harvested for analysis each day from 7 to 17 days after sowing, giving a total of eight hundred twenty-five leaf samples to analyze. Venation patterns were extracted and analyzed using custom-made software written with Matlab. Overall, compared with the wild type, mutants with the highest auxin transport (max4-1 and max3-9) had different vein patterns at early developmental stages, confirming a role for auxin transport in vein patterning. However, veins of mutants and wild type connected at similar angles, which is not consistent with the auxin canalization hypothesis, as originally formulated.

Small-scale morphology of gas hydrate is important for understanding the formation of gas hydrate deposits, for estimating the concentrations of gas hydrate from geophysical data, and for predicting their response to climate change or commercial production. The recent use of borehole pressure coring tools has allowed marine gas-hydrate-bearing sediments to be recovered with centimeter to sub-millimeter gas hydrate structures preserved in their in situ condition. Once these sediment samples are recovered at in situ temperature and pressure, nondestructive analyses, including gamma density, P-wave velocity, and X-ray imaging, are used to examine the character of the gas hydrate relative to the structure of the surrounding sediment. Gas hydrate morphology from pressure core data is summarized from the recent national gas hydrate expeditions of India, China, and Korea, as well as from Ocean Drilling Program Leg 204, Integrated Ocean Drilling Program Expedition 311, and the Gulf of Mexico Chevron-Texaco Joint Industry Project. The most striking result is the variability of gas hydrate morphology in clay, ranging from complex vein structures to an invisible pore-filling matrix. Both of these morphologies have been observed in clay sediments at gas hydrate saturations equivalent to 30-40% of pore volume. A clear knowledge of detailed gas hydrate morphology will provide important data to help determine the mechanisms of gas hydrate deposit formation and also provide crucial data for modeling the kinetics of deposit dissociation, from both natural and artificial causes. The morphology also has large effects on sedimentary physical properties, from seismic velocities on a large scale to borehole electrical resistivities on a smaller scale, and gas hydrate morphology will therefore impact estimation of gas hydrate saturation from geophysical data. The detailed morphology of gas hydrate is an essential component for a full understanding of the past, present, and future of any gas hydrate environment.

Angiopoietin-1 (Ang-1), the main ligand for the endothelial cell (EC)-selective Tie-2 receptors, promotes survival, proliferation, migration and differentiation of these cells. Despite its importance in various aspects of vascular biology, the mechanisms of action of the Ang-1/Tie-2 receptor pathway have not been fully explored. / To identify the downstream modulators of Ang-1, we evaluated changes in the transcriptome of human umbilical vein endothelial cells (HUVECs) treated with Ang-1 protein for four hours by employing the oligonucleotide rnicroarray technology. Eighty-six genes were significantly upregulated by this treatment and forty-nine genes were significantly downregulated. These genes are involved in the regulation of cell cycle, proliferation, apoptosis, transcription and differentiation. Furthermore, we found that the Erk1/2, PI3-Kinase and mTOR pathways are implicated in promoting gene expression in HUVECs in response to Ang-1. Analysis of the microarray data employing the Ingenuity Pathways analysis software to place the regulated genes in the context of biological networks revealed several highly connected nodes including the chemokine Interleukin-8 (IL-8) and the transcription factor Early growth response-1 (Egr-1). Due to the importance of these genes in promoting angiogenesis, we decided to evaluate their roles in Ang-1/Tie-2 receptor signaling and biological effects. / Ang-1 induced IL-8 expression in a time- and dose-dependent manner in ECs through both transcriptional and post-transcriptional mechanisms. To study the functional role of Ang-1-induced IL-8, we generated HUVECs that overexpress Ang-1. In these cells, neutralizing IL-8 significantly reduced EC proliferation and migration. IL-8 promoter activity experiments and gel shift assays revealed the involvement of the transcription factor AP-1 in Ang-1-induced IL-8. Ang-1 stimulated the phosphorylation of c-Jun through activation of Erk1/2, JNK and PI-3 kinase pathways. Similarly, Ang-1 provoked the expression and DNA binding of Egr-1 in HUVECs. Employing siRNA and DNAzyme to specifically knock-down Egr-1, we found that Ang-1-induced Egr-1 also promotes EC proliferation and migration. / We conclude that Ang-1 provokes a coordinated response intended to promote EC survival, proliferation, and angiogenesis and to inhibit EC apoptosis. Ang-1 induces EC proliferation and migration in part through the secretion of the soluble mediator Interleukin-8 and through induction of the transcription factor Egr-1.

Plautines venas, kaip ir širdies miokardą, kontroliuoja širdies nervinė sistema. Nors žmogaus epikardinis nervinis rezginys šiuo metu yra nemažai tyrinėtas, plautinių venų inervacija į tyrėjų akiratį pateko tik po darbų, įrodančių žmogaus plautinių venų ir kairiojo prieširdžio anatominių struktūrų, tarp jų ir intramuralinių nervinių mazgų ir nervinių kelių, svarbų vaidmenį širdies aritmijų genezėje. Šio tyrimo tikslas buvo vizualizuoti plautinių venų nervines struktūras totaliuose žmogaus kairiojo prieširdžio–plautinių venų preparatuose, parodant žmogaus plautinių venų nervų ir nervinių mazgų ryšį su širdies nervine sistema. Mokslinio tyrimo metu spręsti šie uždaviniai: 1) nustatyti inervacijos kelius, kuriais nervai plinta žmogaus plautinėse venose bei įvertinti sritis, išsiskiriančias nervinių struktūrų gausa, 2) ištirti žmogaus plautinių venų žiočių ir jų sienos sluoksnių nervinius komponentus bei jų pasiskirstymo ypatybes, 3) nustatyti parasimpatinei, simpatinei ir aferentinei nervų sistemai priskiriamų žymenų, atitinkamai cholinacetiltansferazės, tirozinhidroksilazės, su kalcitonino genu susijusio peptido ir substancijos P, lokalizaciją ir pasiskirstymo ypatumus žmogaus plautinėse venose. Šiame darbe atliktuose neuromorfologiniuose tyrimuose buvo panaudotos žmogaus vaisių ir suaugusių žmonių širdys, paimtos autopsijų metu. Plautinių venų nervinis rezginys išryškintas, taikant histocheminį acetilcholinesterazės metodą ir imunohistochemines reakcijas. Remiantis tyrimo... [toliau žr. visą tekstą] / Although the crucial role in a spontaneous atrial fibrillation falls on cardiomyocytes of the human pulmonary veins, the autonomic nervous system is not considered only as the strong regulator of atrial electrophysiology but it is also the major initiator of atrial fibrillation due to a disordered interaction between the atrial autonomic nerves and the cardiomyocytes of the pulmonary vein. The aim of the present study was to investigate the intrinsic neural plexus on whole (non–sectioned) human pulmonary veins. The objectives of the study was: 1) to determine the sources and morphology of nerve routes by which intrinsic nerves supply the human pulmonary veins, 2) to examine the neural structures located within distinct wall layers of the human pulmonary veins, 3) to identify the distribution and expression of tyrosine hydroxylase, choline acetyltransferase, calcitonin gene related peptide and substance P positive nerve structures on the human pulmonary veins as corresponding markers for sympathetic, parasympathetic and sensory nerve cells and fibers. Twenty–two hearts of the human fetuses and thirty five hearts of the adult humans containing the full set of pulmonary veins were investigated applying a histochemical methods for acetylcholinesterase to stain intrinsic neural structures with their subsequent stereomicroscopic examination. ChAT, TH, substantia P and CGRP immunoreactive nerves structures were also studied in the pulmonary veins sections, obtained from the six... [to full text]

Several mechanisms have been proposed to explain the process of vein pattern formation in plant tissues. The most widely accepted amongst biologists is the canalization hypothesis, derived from pea root and stem experiments. According to this hypothesis, a signal, thought to be the phytohormone auxin, is transported polarly from cell to cell from the shoot to the root and is canalized progressively into narrow channels of high auxin fluxes that later differentiate to become vascular tissue. In this project, we set out to test whether auxin canalization drives vein pattern formation, using Arabidopsis thaliana mutants with increased auxin transport (max4-1, max3-9, max2-1 and max1-1). We predicted that the mutants would have distinct vein patterns and especially different angles between the primary and secondary veins, compared to the wild type. First rosette leaves of 15 plants per genotype were harvested for analysis each day from 7 to 17 days after sowing, giving a total of eight hundred twenty-five leaf samples to analyze. Venation patterns were extracted and analyzed using custom-made software written with Matlab. Overall, compared with the wild type, mutants with the highest auxin transport (max4-1 and max3-9) had different vein patterns at early developmental stages, confirming a role for auxin transport in vein patterning. However, veins of mutants and wild type connected at similar angles, which is not consistent with the auxin canalization hypothesis, as originally formulated.

Chronic Venous Insufficiency (CVI) is a condition in present in almost 27% of adults in which an insufficient amount of blood is pumped back to the heart due to damaged or poorly apposed one-way valves in the leg veins. During forward flow, vein valves allow blood to return to the heart while posing very little resistance to the flow. During gravity-driven reverse flow, normal valves close and prevent blood from flowing backward through the valve. Incompetent, or damaged, vein valves cannot prevent this reverse flow and lead to a pooling of blood at the feet. CVI is a painful disease presents itself in various ways, including varicose veins, ulcerations of the lower extremities, and severe swelling. Current therapies and treatments include compressive stockings, destruction or removal of affected veins, valve repair, and valve transplants. The implantation of prosthetic vein valves is a future treatment option that does not require an invasive surgery, human donor, or lengthy hospital stay. While no prosthetic vein valves are currently commercially available, this thesis describes the design, verification, and validation of a novel prosthetic vein valve. Verification tests include CFD simulations, functional tests, mechanical tests, and in vitro thromogenicity tests. The validation of the device was done through an animal study in sheep external jugular veins. CFD analysis verified that shear rates within the valve support its lower thrombogenicity as compared to a previous vein valve. Benchtop tests demonstrate superiority in short-term patency over a previous polymer valve. In a sheep study, patency was shown at 6 weeks, surpassing many autograft valves and showing great potential to meet the goal of 3 month patency in sheep.

Introdução – O tratamento da hipertensão portal continua sendo um desafio e muitos desses pacientes necessitam até transplante de fígado, como tratamento definitivo. Nesse contexto a derivação porto-sistêmica intra-hepática transjugular (Transjugular Intrahepatic Portosystemic Shunt – TIPS) surgiu como uma alternativa atraente para esta complicação da doença hepática crônica, sobretudo por não requerer laparotomia e efetivamente reduzir a pressão portal. O conhecimento da distância entre as veias hepáticas e os ramos portais e outros dados anatômicos, no fígado cirrótico, são requisitos importantes no planejamento e execução desse procedimento. Objetivos - Determinar as distâncias e diâmetros das veias hepáticas direita e média para os ramos portais e para a bifurcação da veia porta, no fígado cirrótico humano, com vistas à construção do TIPS. Tipo de estudo – Estudo anatômico descritivo e macroscópico em moldes vasculares de resina obtidos por corrosão de fígados humanos isolados e cirróticos. Material e método – O estudo foi autorizado pelo Comitê de Ética em Pesquisa do HUOC/Procape-UPE e todos os pacientes, ou seus representantes legais, assinaram Termo de Consentimento Livre e Esclarecido. Foram obtidos 21 moldes de resina acrílica dos ramos portais e veias hepáticas de fígados cirróticos, de pacientes transplantados, dos hospitais Jayme da Fonte e Universitário Oswaldo Cruz, do Recife/PE. Após a completa corrosão do parênquima, foram medidas as distâncias e diâmetros das veias hepáticas e ramos da veia porta. Para testar a hipótese de diferença da média estimada em relação a um valor de referência, foi aplicado o teste t-Student para uma amostra. Resultados - A distância média da veia hepática direita para o ramo direito da veia porta e para a sua bifurcação foram, respectivamente, de 33 (±6,4) e 36 (±7,4) mm, ambos significativamente menores (p<0,0001 e p<0,0002) que os resultados encontrados na literatura, em fígados normais. A distância média da veia hepática média para o ramo direito e para o ramo esquerdo da veia porta foi, respectivamente, de 36 (±6,8) e 26 (±8,8) mm . Conclusão – As distâncias entre a veia hepática direita e o ramo direito da veia porta ou a bifurcação da mesma, em fígados cirróticos, foram significativamente menores que as anteriormente relatadas em fígados normais. A veia hepática média é confirmada como uma via alternativa adequada. / Introduction - The treatment of portal hypertension remains a challenge and many of these patients need liver transplantation as definitive treatment. In this context the Transjugular Intrahepatic Portosystemic Shunt (TIPS) has emerged as an attractive alternative to this complication of chronic liver disease, especially for not requiring laparotomy and effectively reducing the portal pressure. Knowing the distance between the hepatic veins and portal branches and other anatomical data in the cirrhotic liver, they are important requirements in the planning and execution of this procedure. Purpose: To determine spatial arrangements and diameters of right and middle hepatic veins relative to portal vein branches in cirrhotic human livers, gaining strategic insight to percutaneous procedures as transjugular intrahepatic portosystemic shunt. (TIPS). Materials and Methods: This study was authorized by an area Research Ethics Committee, and each study subject or legal representative granted signed informed consent. Acrylic corrosion casts of 21 resected cirrhotic livers were generated. Diameters of hepatic veins and portal branches and pertinent intervening distances were measured. To assess differences in estimated average (relative to reference values), Student's t-test for one sample was applied. Results: Mean distances from right hepatic vein to right portal branch and to portal vein bifurcation were 33±6.4 mm and 36±7.4 mm, respectively, both significantly shorter than published reference values in healthy human livers (p<0.0001 and p<0.0002, respectively). Mean distances from middle hepatic vein to right and left branches of portal vein were 36±6.8 mm and 26±8.8 mm, respectively. Conclusion: Distances separating right hepatic vein and portal vein (right branch and bifurcation) are diminished in cirrhotic livers compared to healthy ones. The middle hepatic vein is confirmed as a suitable alternative route.

A doença venosa crônica (DVC) é uma desordem complexa que compreende sinais e sintomas que variam das telangiectasias às úlceras ativas. A DVC é classificada de acordo com aspectos clínicos, etiológicos, anatômicos e fisiopatológicos (CEAP) em sete classes variando de C0 à C6. A principal causa da DVC é a hipertensão venosa que altera o fluxo venoso e, consequentemente, a força de cisalhamento que induz alterações fenotípicas nas células endoteliais que passam a expressar mediadores pró-inflamatórios e pró-trombóticos, que levam à adesão de leucócitos, ao aumento do estresse oxidativo, da permeabilidade vascular e do dano endotelial e ao remodelamento tecidual e vascular.Em virtude dos inúmeros mecanismos e da diversidade de moléculas envolvidas na patogênese e progressão da DVC, é essencial conhecer a interação entre elas e também saber quais são as moléculas (biomarcadores) que se correlacionam positivamente ou negativamente com a gravidade da doença. Foram avaliados os níveis de Interleucina-6 (IL-6), sL-selectina, sE-selectina, sP-selectina, molécula de adesão intercelular-1solúvel (sICAM-1), molécula de adesão das células vasculares-1 solúvel (sVCAM-1), ativador tecidual do plasminogênio (tPA), atividade do inibidor do ativador do plasminogênio-1 (PAI-1), trombomodulina solúvel (sTM), fator de von Willebrand (vWF), metaloproteinase de matriz (MMP)-2, MMP-3, MMP-9, inibidor tecidual das MMPs -1 (TIMP-1), angiopoietina-1 e -2, sTie-2 e s-Endoglina e fator de crescimento do endotélio vascular (VEGF) no sangue coletado da veia braquial de 173 mulheres com DVC primária divididas em grupos C2, C3, C4 e C4 menopausadas (C4m) e de 18 voluntárias saudáveis (grupo C0a). Foram também analisados os níveis urinários de ent-prostaglandina F2&#945; nesses grupos. Não foram encontradas diferenças estatisticamente significativas com relação às concentrações sanguíneas e urinárias de sE-selectina, sP-selectina, sICAM-1, atividade de PAI-1, MMP-3, razão TIMP-1/MMP-3, angiopoietin-2, razão angiopoietina-1/angiopoietina-2, s-Endoglina e ent-prostaglandina F2&#945; entre os grupos estudados, possivelmente devido à alta variabilidade na concentração desses biomarcadores entre as participantes do mesmo grupo. Entretanto, as concentrações sanguíneas de IL-6 sL-selectina, sVCAM-1, tPA, vWF, sTM, MMP2, MMP-9, TIMP-1, razão TIMP-1/MMP-2, razão TIMP-1/MMP-9, angiopoietina-1 e VEGF foram estatisticamente diferentes entre os grupos. Não foi identificado nenhum biomarcador que se correlacionasse diretamente ou inversamente com a progressão da DVC, provavelmente devido à diversidade de fatores envolvidos e à complexa interação entre eles durante o curso da doença. / Chronic Venous Disease (CVD) is a complex disorder, which encompasses signs and symptoms that vary from telangiectasias to active ulcers. The CVD is classified according Clinical, Etiologic, Anatomical and Pathophysiological (CEAP) aspects into seven classes varying from C0 to C6. The main cause of CVD is venous hypertension, which alters venous flow and consequently, shear stress. Abnormal shear stress induces phenotypic changes in endothelial cells that start to express pro-inflammatory and pro-thrombotic mediators that lead to leukocyte adhesion, oxidative stress, increased vascular permeability and endothelial cell damage and tissue and vascular remodeling. Due to several mechanisms and the diversity of molecules involved in the pathogenesis and progression of CVD, is essential to know the interplay between them and which are the molecules (biomarkers) that correlate positively and negatively with the severity of the disease. We investigated the levels of interleukin-6 (IL-6), sL-selectin, sE-selectin, sP-selectin, soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) activity, soluble thrombomodulin (sTM), von Willebrand factor (vWf), matrix metalloproteinase (MMP)-2, MMP-3, MMP-9, tissue inhibitor of metaloproteinases-1 (TIMP-1), angiopoietin-1 and -2, sTie-2, s-Endoglin, vascular endothelial growth factor (VEGF) in the blood taken from the brachial vein of 173 patients with primary CVD divided into C2, C3, C4 and menopaused C4 (C4m) groups and 18 healthy volunteers (C0a group).We also investigated the urinary levels of ent-prostaglandin F2&#945; in these groups. There was no statistically significant difference between groups with respect to blood or urinary levels of sE-selectin, sP-selectin, sICAM-1, PAI-1 activity, MMP-3, TIMP-1/MMP-3 ratio, angiopoietin-2, angiopoietin-1/angiopoietin-2 ratio, s-Endoglin and ent-prostaglandin F2&#945;, likely due to the high variability of these biomarkers concentration among participants within the same group. However, blood levels of IL-6, sL-selectin, sVCAM-1, tPA, vWF, sTM, MMP-2, MMP-9, TIMP-1, TIMP-1/MMP-2 ratio, TIMP-1/MMP-9 ratio, angiopoietin-1 and VEGF were statistically different between groups. It was not identified any biomarker that correlated directly or inversely with the progression of CVD, probably due to the diversity of factors involved and the complex interplay between them in the course of the disease.

Introdução – O tratamento da hipertensão portal continua sendo um desafio e muitos desses pacientes necessitam até transplante de fígado, como tratamento definitivo. Nesse contexto a derivação porto-sistêmica intra-hepática transjugular (Transjugular Intrahepatic Portosystemic Shunt – TIPS) surgiu como uma alternativa atraente para esta complicação da doença hepática crônica, sobretudo por não requerer laparotomia e efetivamente reduzir a pressão portal. O conhecimento da distância entre as veias hepáticas e os ramos portais e outros dados anatômicos, no fígado cirrótico, são requisitos importantes no planejamento e execução desse procedimento. Objetivos - Determinar as distâncias e diâmetros das veias hepáticas direita e média para os ramos portais e para a bifurcação da veia porta, no fígado cirrótico humano, com vistas à construção do TIPS. Tipo de estudo – Estudo anatômico descritivo e macroscópico em moldes vasculares de resina obtidos por corrosão de fígados humanos isolados e cirróticos. Material e método – O estudo foi autorizado pelo Comitê de Ética em Pesquisa do HUOC/Procape-UPE e todos os pacientes, ou seus representantes legais, assinaram Termo de Consentimento Livre e Esclarecido. Foram obtidos 21 moldes de resina acrílica dos ramos portais e veias hepáticas de fígados cirróticos, de pacientes transplantados, dos hospitais Jayme da Fonte e Universitário Oswaldo Cruz, do Recife/PE. Após a completa corrosão do parênquima, foram medidas as distâncias e diâmetros das veias hepáticas e ramos da veia porta. Para testar a hipótese de diferença da média estimada em relação a um valor de referência, foi aplicado o teste t-Student para uma amostra. Resultados - A distância média da veia hepática direita para o ramo direito da veia porta e para a sua bifurcação foram, respectivamente, de 33 (±6,4) e 36 (±7,4) mm, ambos significativamente menores (p<0,0001 e p<0,0002) que os resultados encontrados na literatura, em fígados normais. A distância média da veia hepática média para o ramo direito e para o ramo esquerdo da veia porta foi, respectivamente, de 36 (±6,8) e 26 (±8,8) mm . Conclusão – As distâncias entre a veia hepática direita e o ramo direito da veia porta ou a bifurcação da mesma, em fígados cirróticos, foram significativamente menores que as anteriormente relatadas em fígados normais. A veia hepática média é confirmada como uma via alternativa adequada. / Introduction - The treatment of portal hypertension remains a challenge and many of these patients need liver transplantation as definitive treatment. In this context the Transjugular Intrahepatic Portosystemic Shunt (TIPS) has emerged as an attractive alternative to this complication of chronic liver disease, especially for not requiring laparotomy and effectively reducing the portal pressure. Knowing the distance between the hepatic veins and portal branches and other anatomical data in the cirrhotic liver, they are important requirements in the planning and execution of this procedure. Purpose: To determine spatial arrangements and diameters of right and middle hepatic veins relative to portal vein branches in cirrhotic human livers, gaining strategic insight to percutaneous procedures as transjugular intrahepatic portosystemic shunt. (TIPS). Materials and Methods: This study was authorized by an area Research Ethics Committee, and each study subject or legal representative granted signed informed consent. Acrylic corrosion casts of 21 resected cirrhotic livers were generated. Diameters of hepatic veins and portal branches and pertinent intervening distances were measured. To assess differences in estimated average (relative to reference values), Student's t-test for one sample was applied. Results: Mean distances from right hepatic vein to right portal branch and to portal vein bifurcation were 33±6.4 mm and 36±7.4 mm, respectively, both significantly shorter than published reference values in healthy human livers (p<0.0001 and p<0.0002, respectively). Mean distances from middle hepatic vein to right and left branches of portal vein were 36±6.8 mm and 26±8.8 mm, respectively. Conclusion: Distances separating right hepatic vein and portal vein (right branch and bifurcation) are diminished in cirrhotic livers compared to healthy ones. The middle hepatic vein is confirmed as a suitable alternative route.