Postnatal Ontogenetic Development of Neurogenic and Myogenic Control in the Rat Portal Vein

The postnatal ontogenetic development of neuro-effector control in vascular smooth muscle of the singleunit type has been studied in the rat portal vein. Contractile activity was recorded isometrically in isolated preparations from rats 2–38 days of age and in adults rats. Spontaneous activity, characteristic of the adult portal vein, appeared abruptly during the third postnatal week. Whereas, induced responses to noradrenaline (NA) and acetylcholine (Ach) appeared early during the first week and responses to transmural nerve stimulation occurred at the end of the first week. The appearance of spontaneous activity was accompanied by significant increases in sensitivity to NA (log Ed₅₀) and to transmural nerve stimulation (frequency giving half maximum response), but not to Ach. Also, maximum responses for NA and nerve stimulation relative to Ach responses tended to increase during the first there weeks. It is concluded that the development of a mechanism supporting myogenic propagation as revealed by highly synchronized spontaneous contractions is an important factor for promoting the effectiveness of sympathico-adrenergic control in this type of vascular smooth muscle.     

The Effect of ATP and Related Compounds on Spontaneous Mechanical Activity in the Rat Portal Vein

The effects of ATP, ADP, AMP and adenosine were studied on the spontaneous mechanical activity of the rat portal vein. It was found that ATP and ADP, in concentrations higher than 300 μM, caused a transient tetanus, followed by inhibition, and at lower concentrations an increase in the frequency and amplitude of the spontaneous contractions. AMP and adenosine on the other hand, inhibited spontaneous activity, by reducing the amplitude of contractions and increasing their frequency. The effects were dose-dependent. ATP was found to be 2.2 times more potent than ADP, while AMP and adenosine were equipotent. Weak inhibitory effects were obtained with GMP, guanosine and adenine, while GTP, 3′5′-cyclic AMP and guanine had no effect. ATP and ADP increased the K-contracture, while AMP and adenosine relaxed it. The effects of ATP were augmented in Mg-free solutions and partially inhibited in Mg-high solutions in the normally polarized muscle, while Mg had no influence on the ATP-induced contraction in the depolarized muscle. Theophylline potentiated the inhibitory response to AMP and adenosine. Adrenergic and cholinergic blockers had no influence on the response to ATP, ADP, AMP or adenosine. It is suggested that the effects of ATP and ADP are linked with Ca⁺⁺ movements across the membrane, while AMP and adenosine might stimulate intracellular metabolism causing increased intracellular Ca⁺⁺ binding.     

Oxygen Consumption and Lactate Production of the Rat Portal Vein in Relation to its Contractile Activity

Energy turnover in the isolated rat portal vein was investigated by measurement of oxygen consumption (Jo₂) and lactate production (J_LA) under simultaneous recording of mechanical activity. In spontaneous activity under aerobic conditions and at optimal muscle length Jo₂ and J_LA were 0.55 and 0.62/μmol/min g. respectively, corresponding to an ATP-production of 4.3 μmol/min g. When muscle length was changed, an approximately linear relation was found between energy turnover and mean isometric tension. The tension-independent part of ATP-production was 3.0 μmol/min g. In Ca²+-free solution the metabolic rate was 20 % lower still. Jo₂ was nearly equal in isometric contractions and in afterloaded isotonic contractions from the same initial muscle length. During a maximal tonic contracture in K+-depolarized portal vein Jo₂ increased to about twice that in spontaneous activity. Changes in contracture force by variations in muscle length or in [Ca²+]₀ were associated with identical linear relations between Jo₂ and active tension. This relation was less steep than the corresponding relation for spontaneous activity. The anaerobic lactate production of the portal vein was 2.7 times the aerobic level. The accelerated glycolysis did not compensate for eliminated oxidative metabolism. Under substrate-free aerobic conditions no lactate was produced by the muscle and compared to the control situation Jo₂ declined more than could be accounted for by reduced mechanical aevtivity alone. The metabolic turnover rate in relation to isometric tension is high in the rat portal vein compared to that of tonic vascular smooth muscle from larger vessels. This correlates with differences in dynamic mechanical properties. At comparable tension levels in the portal vein, the rate of cross-bridge turnover may be higher in spontaneous phasic activity than in sustained contracture.     

肝内型门脉高压症形成中大鼠门静脉零应力状态的变化

用CCl4注射法制备大鼠肝内型门脉高压模型，通过观察门静脉张开角的大小，研究肝内型门脉高压大鼠在模型建立过程中不同时间点门静脉零应力状态的变化。结果发现，在门脉高压症形成中．大鼠门静脉张开角逐渐增大，从CCl4注射第10周起与对照组相比有显著性差异（P〈0．05）。表明在门脉高压形成过程中，门静脉存在非均匀性生长，门脉高压大鼠门静脉的残余应力和应变大于正常大鼠。     

Branching Morphology of the Rat Hepatic Portal Vein Tree: A Micro-CT Study

In contrast to the lung and the myocardium, the liver is a relatively homogeneous organ with fewer anatomic constraints on vascular branching. Hence, we hypothesize that the hepatic vasculature could more closely follow optimization of branching geometry than is the case in other organs. The geometrical and fractal properties of the rat hepatic portal vein tree were investigated, with the aid of three-dimensional micro-computed tomography data. Frequency distributions of vessel radii were obtained at three different voxel resolutions and fitted to a theoretical model of dichotomous branching. The model predicted an average junction exponent of 3.09. Hemodynamic model calculations showed that with generation, relative shear stress decreases. Branching angles were found to oscillate between those predicted by two optimality principles of minimum power loss and volume, and of minimum shear stress and surface. The liver shows a variation in branching morphology similar to that of other organs. Therefore, we conclude that anatomic constraints do not have a major perturbing impact.     

亚硒酸钠对犬门静脉环和兔主动脉条收缩的影响

亚硒酸钠(sodium selenite)0.1～0.5mmol/L使犬门静脉环NE和CaCl_2量效曲线非平行性右移,最大反应压低,显示非竞争性拮抗这两种曲线。亚硒酸钠0.1mmol/L显著抑制犬门静脉环自发性收缩活动。此外,它对由CaCl_2moml/L和NE0.6μmol/L诱发的家兔主动脉条收缩有抑制作用。但亚硒酸钠不能拮抗KCl引起的收缩反应。     

Noninvasive Study of Vasodilatory Activity of Albino Rat Cerebral Arteries

Vasodilating activity of rat cerebral vessels was studied. Methodological peculiarities and chronotropic limits of vasomotor testing were determined. Qualitative and quantitative parameters of dilatation of vessels were determined and similarity of rat dilatation responses and human vasodilatory activity was described. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 11, pp. 587–590, November, 2005     

门静脉内皮细胞损伤与门静脉高压症相互关系的研究

采用Masson三色染色法,辅以形态学观察,研究肝硬变病人(n=30)肝内外门静脉的内皮细胞变化。发现血管内皮细胞有明显损伤,伴血栓形成及管壁结构改建。提示血管内皮细胞损伤与门静脉高压症有密切关系。     

Relative Contribution of Superficially Bound and Extracellular Calcium to Activation of Contraction in Isolated Rat Portal Vein

The spontaneous electrical and mechanical activity of the isolated rat portal vein is abolished after only 2–3 min in nominally Ca-free medium, and after 5–6 min there is no contractile response to depolarizing (122 mM K⁺), Ca-free solution. In the present study we have examined the electrical and mechanical responses of the portal vein to depolarization with simultaneous readministration of Ca²⁺ (2.5 mM) after periods of variable length in Ca-free standard solution. After 30 to 60 min of Ca depletion a slow contracture occurred in response to the high-K⁺ solution with 2.5 mM Ca²⁺. When the period in Ca-free medium was reduced below 30 min an early, faster phase appeared in the contracture response, and this phase was more rapid the shorter the time of Ca depletion. It is suggested that the slow contracture obtained after 30 min or more uses mainly extracellular Ca for activation and that the faster phase seen after shorter periods of Ca depletion is due to release of superficially bound Ca. This latter pool of tissue bound Ca does not alone produce contraction in response to depolarization, suggesting that extracellular Ca is required to trigger the release perhaps through a regenerative process.     

基于W-Net的肝静脉和肝门静脉全自动分割

基于术前CT影像的肝静脉和肝门静脉分割对于进行肝脏分段具有重要的临床价值。但在肝脏的静脉期CT影像中,肝静脉和肝门静脉的灰度差异很小,血管结构也错综复杂,因此自动提取三维的肝静脉和肝门静脉一直是个难题。为解决此难题,提出一种基于卷积神经网络(convolutional neural network,CNN)的网络结构W-Net。该结构利用肝静脉和肝门静脉在三维结构上的差异,为全部肝血管和门静脉的提取分别设置损失函数,通过优化两个损失函数的加权和,自动学习全部肝血管和门静脉的三维结构特征,使全部肝血管和肝门静脉均达到优化的提取效果,两者相减即可得到肝静脉。采用公开数据集3Dircadb01中的10组延迟期腹部CT影像用于网络模型构建,另外10组用于测试。结果显示,肝区全部血管Dice系数达到0.715,准确率达到0.970;肝静脉Dice系数达到0.597,准确率达到0.984;肝门静脉Dice系数达到0.608,准确率达到0.970。通过10组临床数据进行测试,所构建的网络均能将肝静脉和肝门静脉有效地分割开。实验结果表明,所提出的方法具有较好的特征提取能力及泛化能力,在公开数据和临床数据中都有较好的表现。     

不同轴向伸长率下兔股动、静脉的顺应性变化

研究轴向应变对血管顺应性的影响 ,明确能否通过调节吻合张力建立顺应性一致的静脉移植修复动脉缺损模型。取一段做完轴向拉伸实验的血管 (兔股动、静脉分别为 13、12条 ) ,测量不同伸长率下的压力—容积曲线 ,换算为压力—标准容积曲线 ,用幂函数 P=M1 × [еM2 ( v- v0 ) - 1]进行拟合 ,用多项式 M=a1 λ5+a2 λ4 +a3λ3+aλ2 +a5λ+a6 拟合 M- λ数据。由 P=M1 × [еM2 ( v- v0 ) - 1]得出在动脉平均压 (11.78KPa)下血管顺应性 dv/ dp=1/ (M1 ×M2 +11.78M2 )。由张力 T与伸长率 λ的单值对应关系建立起 T与顺应性 dv/ dp的单值对应关系 ,发现在张力 1.19g时 ,在动脉平均压下 ,动静脉的顺应性一致 ,为 0 .0 31,其所对应的动静脉伸长率为 :1.6 7及 1.32     

Intrahepatic Branching Pattern of Portal Vein

The variations in the branching pattern of Portal vein within liver are mandatory factor while dealing with Subsegmental Hepatectomy. The variations in the Intra hepatic portal vein branching need to be recognized when contemplating an initial ligation of the vessels at the porta hepatis during partial hepatectomy. This study, was done in 47 adult human liver specimens and 3 fetal liver specimens. In this study different methods like manual dissection, corrosion cast and Radiological study methods used. During this study the “BIFURCATION” or “TRIFURCATION” pattern of portal vein, accessory branches from its branches and relation between, portal vein and hepatic vein were observed. The knowledge of the portal vein and its intra hepatic branching, including their variations are crucial to ensure surgical success pertaining to different and modern surgical procedures.     

Histaminergic Regulation of Smooth Muscles in Rabbit Pulmonary Arteries

Histaminergic contractile reactions of smooth muscles in rabbit lobar pulmonary arteries were studied using in vitro mechanographic technique. Histamine via activation of H-receptors induced a dose-dependent constriction of smooth muscle segments, while endothelium inhibited histamine-induced contractile reactions. Histamine increased sensitivity of smooth muscle cells in pulmonary artery to sodium nitroprusside.     

Ramification Pattern of the Arteries Supplying the Rabbit Female Genital Organs

Uterine adenocarcinoma occurs in more than 60% of female rabbits aged 4 years and over. To cure or prevent this uterine disorder, ovariohysterectomy should be performed. Although knowledge of the arterial supply to the ovary, uterus, and vagina is required, few studies have described the arterial anatomy. Therefore, we dissected ovarian, uterine, and vaginal arteries in 15 New Zealand White and 15 Japanese White rabbits to clarify the anatomy. The ovarian artery arose from the abdominal aorta, and in 50% of cases, the left artery emerged more cranially than the right artery. The ovarian artery provided the ovarian, uterine, and tubal branches with three branching types. The most frequent type (67% of the halves on the right and 63% of the halves on the left) exhibited three branches that independently arose from the ovarian artery. The uterine artery usually originated from the umbilical artery, with its ramification pattern divided into two types, having one or two uterine arteries, respectively. The most frequent type (all halves on the right and 83% of the halves on the left) had one uterine artery that originated from the umbilical artery. We observed three types of vaginal artery origins, with the branching type where the vaginal artery arose from the internal iliac artery being the most frequent (97% of the halves on the right and 90% of the halves on the left). The detailed arterial supply pattern of the rabbit female genital organs determined in the present study will be helpful when performing rabbit gynecological surgeries. Anat Rec, 303:1478–1488, 2020. © 2019 American Association for Anatomy