Upregulation of angiotensin AT1a receptors mRNA in the heart and renal medulla after myocardial infarction in rats.

The myocardial infarct causes prolonged activation of the renin-angiotensin system and profoundly influences cardiac performance and renal excretory capabilities. The aim of the present study was to determine whether the myocardial infarct is also associated with an altered expression of AT1a receptors (AT1aR) mRNA in the heart and the kidney. To this end male Sprague-Dawley rats were subjected either to the left coronary artery ligation or to the sham surgery. Four weeks after the surgery the animals were sacrificed. In 11 infarcted and 10 sham-operated rats expression of AT1aR mRNA in the walls of the left and right ventricle of the heart, and in the renal cortex and renal medulla was determined by semiquantitative PCR method. In another group of 10 infarcted and 14 sham-operated rats the diameter of cardiomyocytes in the left and right cardiac ventricle was determined. The size of the infarct in the rats used for mRNA determination and for morphometric measurements was equal to 29.4 +/- 1.8% and to 31.0 +/- 1.2 % of the left ventricular wall, respectively. Expression of AT1aR mRNA was significantly greater in the left (P< 0.01) and right ventricle (P<0.03) of the heart in the infarcted than in the sham operated rats. AT1aR mRNA expression was also significantly greater (P<0.02) in the renal medulla of the infarcted rats than in the renal medulla of the sham operated rats whereas no significant difference was found in the renal cortex. The myocardial infarct was associated with a significant increase of diameter of cardiomyocytes of the left ventricle of the heart (P< 0.0001), however there was no significant correlation between changes in AT1aR mRNA expression and diameter of cardiomyocytes. The results provide evidence that the myocardial infarct results in significant and prolonged upregulation of AT1a receptors mRNA expression in the heart and in the medullary region of the kidney.     

经颈静脉途径制备Beagle犬心脏记忆模型

目的经颈静脉途径应用心室起搏的方法制备心脏记忆犬模型。方法 8只普通级成年健康Beagle犬经腹腔麻醉后,Seldinger’s法穿刺颈外静脉成功后送入心内膜起搏电极,将电极头端固定于右室心尖部,近端连接于脉冲发生器。起搏频率设置较犬窦性心律时的基础心率快15%,保证起搏器连续起搏。结果连续起搏1周后所有动物均成功制备为心脏记忆模型。建模后犬的心率、呼吸、体重与建模前比较,无明显改变;所有模型组犬起搏前心电图均为窦性心律,起搏1周后出现心脏T波记忆,在下壁导联以及胸前导联均出现T波倒置,停止起搏后,心脏T波记忆逐渐消失;模型组犬与正常组犬心肌病理相比,无明显改变。结论经颈静脉途径应用心室起搏法建立心脏记忆犬模型的方法,具有手术简单,创伤小,诱发方式与临床相似等优点,为深入展开心脏记忆的机制研究奠定基础。     

Catheter-based antegrade intracoronary viral gene delivery with coronary venous blockade

The purpose of this study is to evaluate the feasibility of percutaneous antegrade myocardial gene transfer (PAMGT). A consistent and safe technique for in vivo gene transfer is required for clinical application of myocardial gene therapy. PAMGT with concomitant coronary venous blockade was performed in 12 swine. The myocardium was preconditioned with 1 min of occlusion of the left anterior descending and left circumflex arteries. The anterior interventricular vein was occluded during left anterior descending artery delivery, and the great cardiac vein at the entrance of the middle cardiac vein was occluded during left circumflex artery delivery. With arterial and venous balloons inflated (3 min) and after adenosine (25 mug) injection, PAMGT was performed by antegrade injection of an adenoviral solution (1 ml of 10(11) plaque-forming units in each coronary artery) carrying beta-galactosidase or saline through the center lumen of the angioplasty balloon. In one set of animals, PAMGT was performed with selective coronary vein blockade (n = 9); in another set of animals, PAMGT was performed without coronary vein blockade (n = 5). At 1 wk after gene delivery, the animals were killed. Quantitative beta-galactosidase analysis was performed in the left and right ventricular walls. PAMGT was successfully performed in all animals with and without concomitant occlusion of the coronary veins. Quantitative beta-galactosidase analysis showed that PAMGT with coronary blockade was superior to PAMGT without coronary blockade. beta-Galactosidase activity increased significantly in the beta-galactosidase group compared with the saline group: 1.34 +/- 0.18 vs. 0.81 +/- 0.1 ng (P 相似文献   

Adenovirus-mediated stromal cell-derived factor-1 alpha gene transfer improves cardiac structure and function after experimental myocardial infarction through angiogenic and antifibrotic actions

Stromal cell-derived factor 1α (SDF-1) is not only a major chemotactic factor, but also an inducer of angiogenesis. The effects of SDF-1α on the left ventricular remodeling in a rat myocardial infarction (MI) model were analyzed. Myocardial infarction was induced by ligation of the left coronary artery in rats. 0.5 × 10¹⁰ pfu/ml AdV-SDF-1 or 0.5 × 10¹⁰ pfu/ml Adv-LacZ were immediately injected into the infarcted myocardium, 120 μl cell-free PBS were injected into the infarcted region or the myocardial wall in control, and sham group, respectively. We found that AdV-SDF-1 group had higher LVSP and ±dP/dt_max, lower LVEDP compared to control or Adv-LacZ group. The number of c-Kit⁺ stem cells, and gene expression of SDF-1, VEGF and bFGF were obviously increased, which was associated with reduced infarct size, thicker left ventricle wall, greater vascular density and cardiocytes density in infarcted hearts of AdV-SDF-1 group. Furthermore, the expression of collagen type I and type III mRNA, and collagen accumulation in the infarcted area was lower, which was associated with decreased TGF-β1, TIMP-1 and TIMP-2 expression in AdV-SDF-1 group. Conclusion: SDF-1α could improve cardiac structure and function after Myocardial infarction through angiogenic and anti-fibrotic actions.     

Beneficial effect of perindopril, an angiotensin-converting enzyme inhibitor, on left ventricular performance and noradrenaline myocardial content during cardiac failure development in the rat

The left coronary artery in rats was ligated for a period of 15 days to induce hypertrophy of the non-infarcted myocardium. Left ventricular performances were evaluated in the working heart model. In addition, cardiac hypertrophic indices and noradrenaline content were measured. Variables were determined in the absence or presence of the angiotensin-converting enzyme inhibitor, perindopril. A 35 and 60% decrease in the coronary and cardiac output, respectively, and a 57% decrease in the noradrenaline content of the non-infarcted left ventricular free wall were seen. Furthermore, a 15% increase in the heart/body weight ratio was observed in the infarcted group. After chronic treatment of the animals with perindopril (2 mg.kg-1 body weight, per os), coronary and cardiac output were impaired to a lesser extent: 8 and 35% respectively, with only a 15% decrease in the noradrenaline content of the non-infarcted left ventricular free wall. Furthermore, the increase in heart/body weight ratio was significantly less than in the nontreated infarct group (7%). We conclude that the beneficial effects of converting enzyme inhibition, during the development of myocardial infarction, on left ventricular performances are associated with a decrease in the hypertrophic indices and a normalization of sympathetic activity.     

改良颈静脉置管术在自身给药成瘾模型优化中的作用研究

目的:探讨技术和方法的改进,提高动物颈静脉置管以及药物成瘾自身给药模型构建的成功率,为成瘾研究提供更稳定和高效的建模方法。方法:对建立自身给药模型的传统颈静脉置管术进行改良,选取成年雄性SD大鼠60只,按照随机数字表法分为传统手术组(n=30)和改良手术组(n=30),分别完成颈静脉置管术后,按照随机数字表法,再将每组分为对照训练组(n=15)和成瘾训练组(n=15),构建大鼠自身给药模型,观察两组大鼠自身给药模型成功率。结果:大鼠的颈静脉置管手术可能出现的手术并发症主要包括堵管、漏管、感染甚至死亡等,最主要的并发症是漏管,占比最大。颈静脉置管传统手术组手术成功率为43.33%±3.333,颈静脉置管改良手术组手术成功率为90.00%±3.333,显著高于颈静脉置管传统手术组(P0.05)。两组成瘾训练组有效鼻触次数均分别明显高于其对照训练组(P0.05)。结论:大鼠改良后的颈静脉置管手术效果明显优于传统手术,颈静脉置管手术成功率明显提高。     

Catecholamine effects on cardiac remodelling,oxidative stress and fibrosis in experimental heart failure

The aim of the study was to assess the relationships between oxidative stress, cardiac remodelling and fibrosis on an experimental model of heart failure with adrenergic stimulation. Large myocardial infarction (approximately 50% of the left ventricle myocardium) was obtained by ligation of the left coronary artery of normotensive male Wistar rats. Sham animals were submitted to left thoracotomy without coronary ligation. In order to perform cardiac stimulation by catecholamines, mini-osmotic pumps were implanted in animals 10 weeks after surgery to deliver noradrenalin for a 2-week period. At the end of this period, the following investigations were performed: haemodynamics, morphometry, fibrosis quantification, plasma and tissue catecholamine assay and oxidative stress status. Coronary ligation induced dilatation of left ventricle with compensatory hypertrophy of the right ventricle and of the remaining left ventricle myocardium. This remodelling process was associated in non-infarcted myocardium with increased collagen infiltration and increased oxidative stress. Ten weeks after surgery, the chronic administration of noradrenalin for 2 weeks did not increase oxidative stress. Noradrenalin, however, induced inotropic stimulation and myocardial hypertrophy, but to a lesser extent in infarcted rats compared to sham rats. Our results suggest that noradrenalin infusion to levels in excess of those seen post-infarction is associated with fibrosis and oxidative stress. Moreover, noradrenalin in infarcted animals caused additional fibrosis without further increasing oxidative stress. The mechanism of catecholamine-induced fibrosis may thus involve different processes such as ischaemia, increased mechanical stress, cytokines and neurohormones.     

Marshall to the rescue in cardiac resynchronization therapy: Left ventricular lead placement in coronary sinus ostial atresia

This case highlights the importance of proper identification of congenital anomalies of the coronary sinus for the successful placement of left ventricular lead during cardiac resynchronization therapy device implantation. We discuss an alternate route for left ventricular lead placement via the vein of Marshall when the coronary sinus ostium in the right atrium was atretic and was facing difficulty initially in detecting the anomaly.     

Neutrophil-mediated accumulation of 2-ClHDA during myocardial infarction: 2-ClHDA-mediated myocardial injury

The pathophysiological sequelae of myocardial infarction include neutrophil infiltration into the infarct zone that contributes to additional damage to viable tissue and removal of cellular debris from necrosed tissue. Reactive chlorinating species produced by myeloperoxidase amplify the oxidant capacity of activated neutrophils. Plasmalogens are a major phospholipid subclass of both endothelial cells and cardiac myocytes. Recent studies have shown that plasmalogens are targeted by neutrophil-derived reactive chlorinating species that lead to the production of alpha-chloro fatty aldehydes. Results herein demonstrate that the alpha-chloro fatty aldehyde 2-chlorohexadecanal (2-ClHDA) accumulates in rat hearts subjected to left anterior descending coronary artery occlusion. Myocardia from rats subjected to surgical infarction had increased 2-ClHDA and neutrophil infiltration levels compared with myocardia from rats subjected to sham surgery. Additionally, infarcted myocardia from rats rendered neutropenic by treatments with an anti-neutrophil antibody had diminished 2-ClHDA and neutrophil infiltration levels compared with infarcted myocardia from normopenic rats; 2-ClHDA was shown to elicit myocardial damage as determined by lactate dehydrogenase release in isolated perfused rat hearts. Additionally, 2-ClHDA treatment of hearts resulted in decreased heart rate and ventricular performance. Taken together, the present results demonstrate a novel neutrophil-dependent myeloperoxidase-based mechanism that results in 2-ClHDA production in response to regional myocardial infarction that may also contribute to cardiac dysfunction.     

In situ delivery of bone marrow cells and mesenchymal stem cells improves cardiovascular function in hypertensive rats submitted to myocardial infarction

This work aimed to evaluate cardiac morphology/function and histological changes induced by bone marrow cells (BMCs) and cultured mesenchymal stem cells (MSCs) injected at the myocardium of spontaneously hypertensive rats (SHR) submitted to surgical coronary occlusion. Female syngeneic adult SHR, submitted (MI) or not (C) to coronary occlusion, were treated 24 h later with in situ injections of normal medium (NM), or with MSCs (MSC) or BMCs (BM) from male rats. The animals were evaluated after 1 and 30 days by echocardiography, histology of heart sections and PCR for the Y chromosome. Improved ejection fraction and reduced left ventricle infarcted area were observed in MSC rats as compared to the other experimental groups. Treated groups had significantly reduced lesion tissue score, increased capillary density and normal (not-atrophied) myocytes, as compared to NM and C groups. The survival rate was higher in C, NM and MSC groups as compared to MI and BM groups. In situ injection of both MSCs and BMCs resulted in improved cardiac morphology, in a more physiological model of myocardial infarction represented by surgical coronary occlusion of spontaneously hypertensive rats. Only treatment with MSCs, however, ameliorated left ventricle dysfunction, suggesting a positive role of these cells in heart remodeling in infarcted hypertensive subjects.     

Susceptibility to systolic dysfunction in the myocardium from chronically infarcted spontaneously hypertensive rats

We explored whether the hypertensive heart is susceptible to myocardial dysfunction in viable noninfarcted tissue post-myocardial infarction (MI), the potential mechanisms thereof, and the impact of these changes on pump function. Six to seven months after the ligation of the left anterior descending coronary artery, left ventricular (LV) myocardial systolic function, as assessed from the percent shortening of the noninfarcted lateral wall segmental length determined over a range of filling pressures (ultrasonic transducers placed in the lateral wall in anaesthetized, open-chest, ventilated rats) and the percent thickening of the posterior wall (echocardiography), was reduced in infarcted spontaneous hypertensive rats (SHR-MI) (P < 0.05) but not in normotensive Wistar-Kyoto (WKY-MI) animals compared with corresponding controls [SHR-sham operations (Sham) and WKY-Sham]. This change in the regional myocardial function in SHR-MI, but not in WKY-MI, occurred despite a similar degree of LV dilatation (increased LV end-diastolic dimensions and volume intercept of the LV end-diastolic pressure-volume relation) in SHR-MI and WKY-MI rats and a lack of difference in LV relative wall thinning, LV wall stress, apoptosis [terminal deoxynucleotidyl transferase biotin-dUTP nick-end labeling (TUNEL)], or necrosis (pathological score) between SHR-MI and WKY-MI rats. Although the change in regional myocardial function in the SHR-MI group was not associated with a greater reduction in baseline global LV chamber systolic function [end-systolic elastance (LV E(es)) and endocardial fractional shortening determined in the absence of an adrenergic stimulus], in the presence of an isoproterenol challenge, noninfarct-zone LV systolic myocardial dysfunction manifested in a significant reduction in LV E(es) in SHR-MI compared with WKY-MI and SHR and WKY-Sham rats (P < 0.04). In conclusion, these data suggest that with chronic MI, the hypertensive heart is susceptible to the development of myocardial dysfunction, a change that cannot be attributed to excessive chamber dilatation, apoptosis, or necrosis, but which in turn contributes toward a reduced cardiac adrenergic inotropic reserve.     

麻醉大鼠左心室插管新方法

目的：探索在0．014’’经皮冠状动脉（PTCA）指引导丝引导下行大鼠左心室插管的方法。方法：30只Wistar大鼠,先后在PTCA导丝引导经右侧颈外动脉,左侧颈外动脉插管至左心室并行血流动力学测定：结果：30只大鼠成功完成一次左心室重复插管,27只大鼠完成重复插管：结论：PTCA指引导丝引导下左心室插管安全并可重复操作。     

Atresia of the right atrial ostium of the coronary sinus

A case of asymptomatic congenital occlusion of the ostium of the coronary sinus is described. The myocardial venous drainage was maintained via a persistent left superior vena cava as well via ectatic, widened atrial veins of the dorsal wall of the left atrium. The study shows that complete ostial occlusion of the coronary sinus does not reduce cardiac venous drainage. The view of the literature allows a comparison with the comprehensive classification of coronary sinus anomalies.     

Insulin-like growth factor 1 improves the efficacy of mesenchymal stem cells transplantation in a rat model of myocardial infarction

Background Previous study demonstrated the improvement of cardiac function was proportional to the number of cells implanted. Therefore, increasing cell survival in the infarcted myocardium might contribute to the improvement of the functional benefit of cell transplantation. Methods and results MSCs were treated with IGF-1 in vitro and infused into the acute myocardial infarction rats via the tail vein. After treatment of MSCs with IGF-1 for 48 h, flow cytometric analysis showed marked enhancement of expression of CXCR4 in the cell surface. After 4 weeks of transplantation, we found 1) a greater number of engrafted MSCs arrived and survived in the peri-infarct region; 2) TnT protein expression and capillary density were enhanced; 3) LV cavitary dilation, transmural infarct thinning, deposition of total collagen in the peri-infarct region and cardiac dysfunction were attenuated. Conclusion 1) IGF-1 treatment has time-dependent and dose-dependent effects on CXCR4 expression in MSCs in vitro. 2) IGF-1 improves the efficacy of MSCs transplantation in a rat model of myocardial infarction mainly via enhancement of the number of cells attracted into the infarcted heart. These findings provide a novel stem cell therapeutic avenue against ischemic heart disease.     

Complications of central venous catheterization from an anatomical point of view

For access to the central venous system numerous percutaneous methods and approaches exist. Questions are often raised concerning which approach is the safest. In 18 human cadavers, we punctured the internal jugular vein via an anterior and posterior approach and the subclavian vein via an infraclavicular route to determine which of these approaches is better with respect to success rate and frequency of puncture complications. The position of the needles was assessed by dissection. Successful venipunctures were achieved in 81% by the posterior approach, as opposed to 58% by the anterior approach and the infraclavicular route. The lowest frequency of complications was attained by the posterior approach (17%) too, whereas the anterior approach (33%) and the subclavian route (25%) had higher complication rates. The main complication of posterior and anterior approaches was inadvertent arterial puncture (9 vs. 19%). At the subclavian approach puncture of a 'wrong' vein was frequent (14%), and the complications included a case of pleura lesion. In conclusion the posterior approach to the internal jugular vein is superior to the other investigated approaches, and therefore, it can reasonably be proposed as a usual route for the insertion of a central venous catheter.     

Delayed Contrast Enhancement Imaging of a Murine Model for Ischemia Reperfusion with Carbon Nanotube Micro-CT

We aim to demonstrate the application of free-breathing prospectively gated carbon nanotube (CNT) micro-CT by evaluating a myocardial infarction model with a delayed contrast enhancement technique. Evaluation of murine cardiac models using micro-CT imaging has historically been limited by extreme imaging requirements. Newly-developed CNT-based x-ray sources offer precise temporal resolution, allowing elimination of physiological motion through prospective gating. Using free-breathing, cardiac-gated CNT micro-CT, a myocardial infarction model can be studied non-invasively and with high resolution. Myocardial infarction was induced in eight male C57BL/6 mice aged 8–12 weeks. The ischemia reperfusion model was achieved by surgically occluding the LAD artery for 30 minutes followed by 24 hours of reperfusion. Tail vein catheters were placed for contrast administration. Iohexol 300mgI/mL was administered followed by images obtained in diastole. Iodinated lipid blood pool contrast agent was then administered, followed with images at systole and diastole. Respiratory and cardiac signals were monitored externally and used to gate the scans of free-breathing subjects. Seven control animals were scanned using the same imaging protocol. After imaging, the heart was harvested, cut into 1mm slices and stained with TTC. Post-processing analysis was performed using ITK-Snap and MATLAB. All animals demonstrated obvious delayed contrast enhancement in the left ventricular wall following the Iohexol injection. The blood pool contrast agent revealed significant changes in cardiac function quantified by 3-D volume ejection fractions. All subjects demonstrated areas of myocardial infarct in the LAD distribution on both TTC staining and micro-CT imaging. The CNT micro-CT system aids straightforward, free-breathing, prospectively-gated 3-D murine cardiac imaging. Delayed contrast enhancement allows identification of infarcted myocardium after a myocardial ischemic event. We demonstrate the ability to consistently identify areas of myocardial infarct in mice and provide functional cardiac information using a delayed contrast enhancement technique.     

Monolayered mesenchymal stem cells repair scarred myocardium after myocardial infarction

Mesenchymal stem cells are multipotent cells that can differentiate into cardiomyocytes and vascular endothelial cells. Here we show, using cell sheet technology, that monolayered mesenchymal stem cells have multipotent and self-propagating properties after transplantation into infarcted rat hearts. We cultured adipose tissue-derived mesenchymal stem cells characterized by flow cytometry using temperature-responsive culture dishes. Four weeks after coronary ligation, we transplanted the monolayered mesenchymal stem cells onto the scarred myocardium. After transplantation, the engrafted sheet gradually grew to form a thick stratum that included newly formed vessels, undifferentiated cells and few cardiomyocytes. The mesenchymal stem cell sheet also acted through paracrine pathways to trigger angiogenesis. Unlike a fibroblast cell sheet, the monolayered mesenchymal stem cells reversed wall thinning in the scar area and improved cardiac function in rats with myocardial infarction. Thus, transplantation of monolayered mesenchymal stem cells may be a new therapeutic strategy for cardiac tissue regeneration.     

Intravenous administration of mesenchymal stem cells improves cardiac function in rats with acute myocardial infarction through angiogenesis and myogenesis

Mesenchymal stem cells (MSCs) are pluripotent cells that differentiate into a variety of cells, including cardiomyocytes and endothelial cells. However, little information is available regarding the therapeutic potency of systemically delivered MSCs for myocardial infarction. Accordingly, we investigated whether intravenously transplanted MSCs induce angiogenesis and myogenesis and improve cardiac function in rats with acute myocardial infarction. MSCs were isolated from bone marrow aspirates of isogenic adult rats and expanded ex vivo. At 3 h after coronary ligation, 5 x 10(6) MSCs (MSC group, n=12) or vehicle (control group, n=12) was intravenously administered to Lewis rats. Transplanted MSCs were preferentially attracted to the infarcted, but not the noninfarcted, myocardium. The engrafted MSCs were positive for cardiac markers: desmin, cardiac troponin T, and connexin43. On the other hand, some of the transplanted MSCs were positive for von Willebrand factor and formed vascular structures. Capillary density was markedly increased after MSC transplantation. Cardiac infarct size was significantly smaller in the MSC than in the control group (24 +/- 2 vs. 33 +/- 2%, P <0.05). MSC transplantation decreased left ventricular end-diastolic pressure and increased left ventricular maximum dP/dt (both P <0.05 vs. control). These results suggest that intravenous administration of MSCs improves cardiac function after acute myocardial infarction through enhancement of angiogenesis and myogenesis in the ischemic myocardium.     

Cardiac telocytes were decreased during myocardial infarction and their therapeutic effects for ischaemic heart in rat

Recently, cardiac telocytes were found in the myocardium. However, the functional role of cardiac telocytes and possible changes in the cardiac telocyte population during myocardial infarction in the myocardium are not known. In this study, the role of the recently identified cardiac telocytes in myocardial infarction (MI) was investigated. Cardiac telocytes were distributed longitudinally and within the cross network of the myocardium, which was impaired during MI. Cardiac telocytes in the infarction zone were undetectable from approximately 4 days to 4 weeks after an experimental coronary occlusion was used to induce MI. Although cardiac telocytes in the non‐ischaemic area of the ischaemic heart experienced cell death, the cell density increased approximately 2 weeks after experimental coronary occlusion. The cell density was then maintained at a level similar to that observed 1–4 days after left anterior descending coronary artery (LAD)‐ligation, but was still lower than normal after 2 weeks. We also found that simultaneous transplantation of cardiac telocytes in the infarcted and border zones of the heart decreased the infarction size and improved myocardial function. These data indicate that cardiac telocytes, their secreted factors and microvesicles, and the microenvironment may be structurally and functionally important for maintenance of the physiological integrity of the myocardium. Rebuilding the cardiac telocyte network in the infarcted zone following MI may be beneficial for functional regeneration of the infarcted myocardium.     

A rapid and non-surgical procedure for jugular catheterization of pigs

A rapid and non-surgical method for jugular catheterization in pigs was set up in 30 piglets of 6.2 kg, 23 pigs of 46 kg and 84 kg and two lactating multiparous sows. The animal was restrained on a V-shaped table (piglets) or with a rope around the mandible (slaughter pigs and sows). The vein was located with the Vacutainer system and a wire guide was inserted into the Vacutainer needle up to the vein lumen. When the needle was removed, the catheter was inserted over the wire guide and advanced until it penetrated the skin and thereafter, the vein wall. The catheter was fixed outside by a large tape and coiled inside a patch just behind the ears. The technique utilizes readily available material and is no more risky for the animal than a single blood sampling. Moreover, it can be performed within 15 to 20 min (including animal restraint) within pens. This new approach might have important implications not only for research purposes by facilitating repeated blood samplings but also for projects which require a rapid and easy method for testing of any kind of pharmaceutical or other type of products under husbandry conditions.