Somatostatin sst5 inhibition of receptor mediated regeneration of rat aortic vascular smooth muscle cells

1. The aim of the present study was to determine the effect of somatostatin (SRIF) on mitogen-induced regeneration of rat aortic vascular smooth muscle cells (VSMC) and for comparison Chinese hamster ovary (CHO)-K1 cells expressing human recombinant sst₅ receptors (CHOsst₅), following partial denudation of a confluent cell monolayer. Regeneration was assessed by measuring areas of recovery into the denuded area and by counting total cell numbers.
2. In VSMC, SRIF (0.1 nM–1 μM) had no effect on the basal levels of regeneration but caused a concentration-dependent inhibition (pIC₅₀ 8.0–8.6) of the stimulated regeneration induced by sub-maximal concentrations of basic fibroblast growth factor (bFGF, 10 ng ml⁻¹), platelet-derived growth factor-BB (PDGF, 5 ng ml⁻¹) or endothelin-1 (ET-1, 100 nM). SRIF (pIC₅₀ 8.8) also inhibited bFGF-induced regeneration of CHOsst₅ cells.
3. In VSMC, the inhibitory action of SRIF on the regeneration induced by bFGF (10 ng ml⁻¹) was due to an anti-proliferative effect, rather than an effect on cell migration, as SRIF (0.1 nM–1 μM) abolished bFGF-induced increases in total cell numbers. The bFGF-induced increase in cell numbers was also abolished by actinomycin D (0.1 μg ml⁻¹).
4. The sst₅ receptor-selective agonist, L-362,855 (pIC₅₀ 10.5), was about 100 times more potent than SRIF at inhibiting bFGF-induced regeneration of both VSMC and CHOsst₅ cells whilst the sst₂ receptor-selective agonist, BIM-23027 (pIC₅₀ 6.8), was approximately 20 times weaker than SRIF.
5. The sst₅ receptor antagonist, BIM-23056 (100 nM), antagonized SRIF-induced inhibition of bFGF-induced regeneration in both VSMC and CHOsst₅ cells (estimated pK_B values 8.8 and 8.3, respectively).
6. SRIF-induced inhibition of bFGF-induced regeneration of VSMC and CHOsst₅ cells was abolished by pretreating cells with pertussis toxin (100 ng ml⁻¹) for 20 h.
7. These findings suggest that SRIF-induced inhibition of the proliferation of rat aortic VSMC is mediated via activation of receptors which are similar to human sst₅ receptors. Furthermore this inhibitory effect is transduced via pertussis toxin-sensitive G_i/G_o proteins.

     

Velocity distributions in the left ventricular outflow tract in patients with valvular aortic stenosis: Effect on the measurement of aortic valve area by using the continuity equation

The cross-sectional velocity distribution in the left ventricularoutflow tract was studied in 40 patients with valvular aorticstenosis. Doppler colour flow mapping and a time-interpolationmethod were used to construct the cross-sectional velocity andtime-velocity integral (TVI) profiles at different levels. Byusing pulsed Doppler, the subaorticflow velocity was sampledfrom the anterior, middle and posterior regions along the diameterof the left ventricular outflow tract (at 0.5 to 1.0 cm proximalto the aortic anulus) in the apical long axis view. Thus, foreach patient, three aortic valve areas were calculated by usingthe continuity equation. Each patient was assigned to one oft/treesubgroups according to the left ventricular ejection fraction(EF): subgroup I with EF25% (n=10), subgroup II with 25%<EF50%(n=17) and subgroup III with EF>50% (n = 13). Velocity distributionsin the three subgroups were compared to each other. Results:(1) The velocity distribution in the left ventricular outflowtract was skewed with the highest velocities and TVIs alongthe anterior wall and septum. The skewness of the velocity distributionwas more pronounced in the apical long axis view than in thefour chamber view (P<0.05). The extent of skewness of theTVI profile was positively correlated to the left ventricularEF both in the long axis view (r=0.63; P<0.001) and in thefour chamber view (r=0–57; P<0.001). (2) Pulsed Dopplersampling from different regions along the diameter produceddifferent TVIs, and therefore yielded significantly differentcalculated aortic valve areas, especially in subgroup III. Due to the skewness of the velocity distribution in the leftventricular outflow tract, location of the pulsed Doppler samplevolume significantly affects the accuracy of aortic valve areacalculation by using the continuity equation, especially inpatients with relatively high left ventricular EF. In patientswith low EF, selection of pulsed Doppler sampling site is lessimportant.     

体外循环不阻断升主动脉下小儿、婴幼儿心内直视术136例分析

目的：评价体外循环下不阻断升主动脉行心内直视术对心肌的保护作用。方法：对１９９５年９月至１９９８年８月在先心心内直视术中应用此法的１３６例婴幼儿进行回顾性分析。全组男７７例,女５９例。年龄３个月～５岁（平均３６５±１２０岁）,体重５～１８（平均１４０１±３５２）。病种包括室间隔缺损１０３例,房间隔缺损１２例,法乐氏四联症１４例,法三２例,肺动脉瓣狭窄２例,部分性房室管通道２例,三尖瓣下移１例。结果：全组死亡３例（２２％）。术后并发症：低心排２例,支气管痉挛３例,二次止血１例。结论：体外循环下不阻断升主动脉行心内直视术是临床效果满意,安全有效的心肌保护方法。     

Right axillary arterial perfusion for a ruptured type B aortic dissection: Report of a case

The results of surgical treatment for a ruptured type B aortic dissection remain far from satisfactory. It is believed that additional perfusion from the right axillary artery might be more beneficial than perfusion from only the femoral artery during surgery for a ruptured thoracic aneurysm. The right axillary perfusion is more likely to perfuse the vital organs proximal to the ruptured area, and thus avoid retrograde emboli. In addition, if the open proximal method is performed, then the right axillary perfusion is able to facilitate the evacuation of air from the aortic lumen. We present herein the case of a patient in whom a ruptured type B acute aortic dissection was successfully treated by applying right axillary perfusion through a left thoracotomy.     

Thoracic Aortic Aneurysms: Role of Echocardiography

This article describes the evolving role of echocardiography for the detection and evaluation of thoracic aortic aneurysms. A brief summary of the clinical, anatomical, and pathological features of the etiologic categories of thoracic aneurysms is presented. The advantages and limitations of echocardiography and its comparison with other techniques (computed tomographic scanning, magnetic resonance imaging, and aortography) are discussed.     

Repair of a ruptured aortic arch aneurysm complicated by postoperative paraplegia: Report of a case

We report herein the rare case of a 79-year-old man who suffered permanent paraplegia after undergoing an otherwise successful total arch replacement for a ruptured aortic arch aneurysm. During cardiopulmonary bypass, perfusion to the distal aorta was maintained from the femoral artery, and postoperative aortography showed intact tributaries from the aorta including the intercostal arteries. Postoperative paraplegia is an extremely rare complication of operations on the aortic arch; however, we speculate that the paraplegia in this patient could be attributed either to a steal phenomenon involving the radicular artery, or to the anatomical particularity of the spinal cord artery described by Cole and Gutelius as the segmental system.     

红花水煎剂对家兔离体主动脉血管的舒张作用

目的　观察红花Carthamustinctorius (DFCT)水煎剂对血管肌条的舒张作用及机制。方法　将家兔离体主动脉肌条放置于灌流肌槽中 ,记录其等长收缩。结果　DFCT对血管肌条静息张力无明显影响 ,但 2 0mg/mLDFCT水煎剂与 10 -5mol/L乙酰胆碱相似 ,可使 10 -6mol/L去甲肾上腺素预收缩血管肌条产生明显的舒张作用。去除内皮细胞、10 -4mol/LL NNA或 10 -5mol/L甲烯蓝可减弱DFCT的舒张血管作用 ,但前列腺素合成抑制剂和 β肾上腺素能受体阻断无明显影响。另外 ,4 0mg/mLDFCT水煎剂可明显抑制去内皮血管肌条去甲肾上腺和KCl的量效收缩反应 ,使其PD2 值分别由对照组 6 0 6± 0 0 9和 1 71± 0 33变为 5 0 7± 0 0 8和 1 35± 0 2 0。结论DFCT水煎剂可通过受体操纵Ca2 + 通道和电压依赖性Ca2 + 通道抑制外Ca2 + 内流 ,使血管肌条舒张 ,其作用与内皮释放的NO有关。     

金粉蕨素抑制大鼠主动脉平滑肌增殖作用及机制

目的 :观察金粉蕨素对牛血清刺激的大鼠主动脉平滑肌细胞增殖的抑制作用 ,并对其作用机制进行初步探讨。方法 :体外培养大鼠主动脉平滑肌细胞 ,以终浓度为 10 %的新生牛血清 (NCS)作为刺激因素 ,用噻唑蓝 (MTT)比色法和细胞计数法观察细胞增殖状况 ,用流式细胞仪分析细胞周期 ,用Westernblot实验测定蛋白表达。结果 :与 10 %牛血清组相比 ,不同浓度金粉蕨素组的MTT测定值与细胞数目均明显下降 (P <0 .0 5 ) ,其下降幅度呈浓度依赖性 ;10 μmol·L-1时达峰值 (P <0 .0 1) ;细胞周期分析显示 ,金粉蕨素组G1期百分比 (85 .1% )高于10 %牛血清组 (70 .0 % ) ,而S期比例 (4 .3% )低于10 %牛血清组 (16.4 % ) ;Westernblot结果显示给药组P ERK1 2蛋白表达明显低于同时间点牛血清组。结论 :金粉蕨素能阻止细胞周期由G0 G1期向S期推进 ,抑制血管平滑肌细胞增殖 ,此作用与其抑制ERK1 2磷酸化、影响MAPK ERK通路激活有关。     

Flow characteristics past jellyfish and St. Vincent valves in the aortic position under physiological pulsatile flow conditions

Thrombus formation and hemolysis have been linked to the dynamic flow characteristics of heart valve prostheses. To enhance our understanding of the flow characteristics past the aortic position of a Jellyfish (JF) valve in the left ventricle, in vitro laser Doppler anemometry (LDA) measurements were carried out under physiological pulsatile flow conditions. The hemodynamic performance of the JF valve was then compared with that of the St. Vincent (SV) valve. The comparison was given in terms of mean systolic pressure drop, back flow energy losses, flow velocity, and shear stresses at various locations downstream of both valves and at cardiac outputs of 3.5 L/min, 4.5 L/min, and 6.5 L/min respectively. The results indicated that both valves created disturbed flow fields with elevated levels of turbulent shear stress as well as higher levels of turbulence in the immediate vicinity of the valve and up to 1 diameter of the pipe (D) downstream of the valve. At a location further downstream, the JF valve showed better flow characteristics than the SV in terms of velocity profiles and turbulent shear stresses. The closure volume of the SV valve was found to be 2.5 times higher than that of the JF valve. Moreover, the total back flow losses and mean systolic pressure drop also were found to be higher in the SV than the JF valve.     

Aortic aneurysm and dissection are not associated with an increased risk for giant cell arteritis/ polymyalgia rheumatica

It has recently been claimed that giant cell arteritis (GCA) is associated with a markedly increased risk of aortic aneurysm formation or rupture. In the present study, the opposite approach was taken, by looking for the incidence of GCA and polymyalgia rheumatica (PMR) in patients with aortic aneurysm, aortic dissection, or both (AA/D). The records of 315 consecutive patients admitted with the diagnosis of AA/D were reviewed. In addition, follow up information was obtained in 82 patients by examination in the outpatient clinic. After careful examination and assessment of clinical and laboratory data, it was found that none of the 82 patients who survived hospitalisation and were available for examination had GCA or PMR. Moreover, review of the retrospective data available from hospital records of the total consecutive 315 patients with AA/D failed to find any patient with a diagnosis of GCA/PMR. In conclusion, the present study did not find an increased prevalence of GCA/PMR among a cohort of Israeli patients with AA/D. Therefore, it is suggested that a thorough investigation aiming to diagnose GCA/PMR is not cost effective in most of the elderly patients presenting with AA/D.