组织器官去细胞的研究进展

经去细胞处理的组织和器官已广泛应用于组织工程和再生医学.组织去细胞的功效与组织来源和去细胞方法密切相关.每种处理方法都会不同程度地影响去细胞后遗留支架的生化组分、超微结构以及机械性能.进而影响宿主对支架材料的反应.拟对最常用的去细胞方法及不同方法对生物支架的作用特点作一综述.     

A study of the antigenic properties of kidney and heart tissues of human embryo in embryogenesis

Summary A study was made of the antigenic species specificity of human embryonic kidney and heart tissues as various developmental periods. The method of anaphylaxis with desensitization on guinea pigs was used.The development of human embryos is paralleled by the rise of the antigenic species specificity of heart and kidney tissues. The nature of species specificity changes occurring, in the heart tissues during embryogenesis some-what differs from that particular to alterations operating in the kidney tissue.(Presented by N. N. Zhukov-Verezhnikov Active Member of AMN SSSR) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 57, No. 4, pp. 108–111, April, 1964     

心脏瓣膜双轴力学特性测试系统的设计

目的为了获得心脏瓣膜力学特性,设计一套高精度双轴拉伸机系统。方法采用上、下位机结构。上位机采用Labview软件编程,设计人机界面,提高系统灵活性和数据处理能力;下位机采用数控语言编程,提高用户编程的简易性和灵活性;采用灵敏度1μm的机械运动硬件模块、16位数据采集卡、光学位移测量方法,提高系统测量精度。对猪的二尖瓣前瓣进行双轴拉伸实验,并将实验结果与国外研究者测试数据进行对比。结果猪二尖瓣前瓣的应力-应变数据与国外研究者测试数据差别为0.4%~3.7%。结论本系统可灵活地对心脏瓣膜和其他生物软组织进行力学特性测试。     

Sex-dependence of the relative number of elastic fibres in human heart valves.

The aim of the current study was to find out whether there are sex-dependent differences in the relative number of elastic fibres in human heart valves. Twenty-six aortic valves, 26 mitral valves, 33 pulmonary valves and 28 tricuspid valves of both sexes were obtained at autopsy from newborn to 89-year-old patients who died of noncardiac diseases. The quantitatively morphometric investigations were carried out on conventionally stained (Resorcinfuchsin) histological sections. The results were qualitatively examined with immuno-histochemically marked (anti-elastin antibodies) histological sections. Earlier examinations by Leutert [1976. Z. Gesamte Inn. Med. 31, 97-104] showed that the atrioventricular valves have the following layers: endothelium, atrial fibroelastic tissue (S1), fibrous tissue, ventricular fibroelastic tissue (S2) and endothelium. In our study, the ventricular side of the semilunar valves corresponds to side S1, whereas the vessel side corresponds to side S2. Three regions of interest were examined on each side of the valves: base, mid and tip. The number of elastic fibres per measuring area for all four human heart valves was significantly higher (p < 0,001) in fibroelastic tissue of side S1 than in fibroelastic tissue of side S2. Neither on side S1 nor on side S2 were there significant gender-related differences in the relative number of elastic fibres per measuring area. The results suggest a characteristic distribution of the elastic fibre system which is not sex-dependent but closely related to the function of the heart valves.     

Immunological specificity of human heart tissues in atherosclerosis

Summary A method of quantitative complement fixation reaction in a 50% titer was used to study sera against the heart tissues of patients with atherosclerosis and healthy individuals. Cross experiments demonstrated that heart tissues differed immunologically in patients with atherosclerosis and healthy individuals.Presented by Active Member AMN SSSR, N. N. Zhukov-Verezhnikov Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 57, No. 1, pp. 75–77, January, 1964     

Stage-specific antigens in human embryonic kidney and heart tissues

Summary With the aid of anaphylaxis reaction and desensitization in guinea pigs it was shown that, apart from the species and organ antigens, kidney and heart tissues of developing human embryo (6–9, 15–19, 35–40 weeks embryo) contained stage-specific antigens; in the corresponding organs of adults the latter were absent.(Presented by Acting Member of the Academy of Medical Sciences of USSR N. N. Zhukov-Verezhnikov) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 57, No. 5, pp. 83–85, May, 1964.     

Effects of decellularization on the mechanical and structural properties of the porcine aortic valve leaflet

The potential for decellularized aortic heart valves (AVs) as heart valve replacements is based on the assumption that the major cellular immunogenic components have been removed, and that the remaining extracellular matrix (ECM) should retain the necessary mechanical properties and functional design. However, decellularization processes likely alter the ECM mechanical and structural properties, potentially affecting long-term durability. In the present study, we explored the effects of an anionic detergent (sodium dodecyl sulfate (SDS)), enzymatic agent (Trypsin), and a non-ionic detergent (Triton X-100) on the mechanical and structural properties of AV leaflets (AVLs) to provide greater insight into the initial functional state of the decellularized AVL. The overall extensibility represented by the areal strain under 60 N/m increased from 68.85% for the native AV to 139.95%, 137.51%, and 177.69% for SDS, Trypsin, and Triton X-100, respectively, after decellularization. In flexure, decellularized AVLs demonstrated a profound loss of stiffness overall, and also produced a nonlinear moment-curvature relation compared to the linear response of the native AVL. Effective flexural moduli decreased from 156.0+/-24.6 kPa for the native AV to 23.5+/-5.8, 15.6+/-4.8, and 19.4+/-8.9 kPa for SDS, Trypsin, and Triton X-100 treated leaflets, respectively. While the overall leaflet fiber architecture remained relatively unchanged, decellularization resulted in substantial microscopic disruption. In conclusion, changes in mechanical and structural properties of decellularized leaflets were likely associated with disruption of the ECM, which may impact the durability of the leaflets.     

Histophysiological effects of fluid resuscitation on heart, lung and brain tissues in rats with hypovolemia

The efficacy of using colloids and crystalloids in the treatment of hypovolemia still remains controversial. An important aspect in treating hypovolemia is to re-establish normal tissue hemodynamics after fluid resuscitation. Production of nitric oxide (NO) or growth factors such as transforming growth factor beta (TGF-beta) has been identified as a key mechanism in physiological and pathological processes in the different systems. This study was designed to investigate the histophysiological effects of resuscitation with different plasma substitutes on the heart, lung and brain tissues following acute blood loss in male Sprague-Dawley rats weighing 250-280g (n=30). After anesthesia with sodium pentobarbital, the left femoral vein and artery were cannulated for the administration of volume expanders and for direct measurement of arterial pressure and heart rate. Twenty rats were bled (5ml/10min) and infused (5ml/10min) with one of four randomly selected solutions, (a) human albumin, (b) gelatin (Gelofusine), (c) dextran-70 (Macrodex); or (d) physiological saline (0.9% isotonic saline). Five control rats were bled without infusion. Tissue samples were taken and fixed in 10% formalin solution, then processed for embedding in paraffin wax. Sections were cut and stained with hematoxylin and eosin. Indirect immunohistochemical labelling was performed to reveal binding of primary antibodies against endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS) and TGF-beta. Mild immunoreactivity of eNOS was observed in endothelial cells of vessels in brain, heart and lung tissues. Increased immunoreactivities of eNOS, iNOS and TGF-beta were observed in the non-fluid resuscitated group in these organs; mild, moderate, moderate and strong immunoreactivities were seen in the albumin, gelatin, physiological saline and dextran-70 treated groups, respectively. Immunoreactivities of iNOS and TGF-beta in the non-fluid resuscitated group were increased significantly, in comparison to the other groups, apart from the dextran-70 treated group. The results of this study show that gelatin solution and physiological saline may be of use after acute blood loss, and dextran-70 is not the preferred resuscitation fluid in the early stages of acute blood loss. It was concluded that albumin solution is the preferred fluid for resuscitation.     

Lack of adherence of IgG-, IgM-, and C3b-sensitized erythrocytes to human heart valves

In a search for receptors for immunoglobulin Fc fragment and activated complement component C3 (C3b) in normal or rheumatic heart valve tissues, sheep erythrocytes sensitized with IgM (IgM EA), IgG (IgG EA) and IgM plus activated complement (IgM EA C3b) were used in a closed-chamber immune adherence technique. Neither this method nor a separate immunofluorescence technique revealed the presence of such immunologic receptors in frozen sections of heart valves.     

人体乳腺组织电阻抗特性的研究

以人体乳腺组织电阻抗特性为依据的乳腺电阻抗扫描成像技术的出现,为乳腺癌的早期检查与辅助诊断开辟了一个新的方向。人体乳腺组织的电阻抗特性反映了乳腺组织的病理生理状态,而对它的测量成为乳腺电阻抗扫描成像技术的前提和基础。主要讨论了人体乳腺组织电阻抗特性的测量方法、测量结果以及存在的问题,对乳腺电阻抗成像技术的应用前景进行了展望。     

神经烯醇化酶、突触素和神经纤维丝蛋白在人胚胎心脏组织中的表达

目的探讨神经烯醇化酶(NSE)、突触素(SYN)和神经纤维丝蛋白(NF)在人胚胎心脏组织不同发育阶段的分布特征。方法应用免疫组织化学法,检测第2~4个月胎龄段共16份人胚胎心脏组织内NF、NSE和SYN蛋白的表达,分析其变化规律。结果第2~4个月龄段,NF、NSE和SYN蛋白在人胚胎心脏组织内均有阳性表达。随着胎龄的增大,NF、NSE和SYN在心脏组织内阳性表达强度值逐渐降低。第2个月龄时,NSE、NF和SYN蛋白呈少量阳性表达,阳性表达强度值分别是86.79±7.75、133.03±13.61和114.32±11.12。第3个月龄时,NSE、NF和SYN阳性表达强度值分别是81.89±9.62,119.91±11.70和93.13±13.63。第4个月胎龄时,NSE、NF和SYN阳性表达强度值分别是72.18±11.97,107.02±10.89和91.17±13.81。应用One-Way ANOVA和LSD-t统计学分析第2~4个月龄段人胚胎心脏组织内NSE、NF和SYN蛋白的各自阳性表达强度值,P0.05。结论第2~4个月龄段,NSE、NF和SYN均在人胚胎心肌组织内表达和呈现特定的分布规律,随胎龄增大,心肌组织内NF、NSE和SYN的表达强度逐渐增强。     

Measurements of steady flow velocity and turbulent stress downstream from jellyfish and St. Vincent aortic heart valves

An experimental investigation was conducted to determine the velocity fields, magnitudes of shear stresses, and regions of stagnation of a jellyfish valve and a St. Vincent tilting-disk valve using laser Doppler anemometry (LDA). All experiments were performed in vitro and at steady volumetric flow rates of 15 and 261/min (representing peak systole). The St. Vincent valve flow field was very unsymmetrical in the measurement plane that spanned the major and minor outflow regions of the valve and persisted at least to 1D downstream. For both flow rates tested, a stagnation region was always observed just behind the occluder. The maximum axial velocity was in the major outflow side and reached 2.54 m/s for peak systole flow of 261/min. Moreover, in the immediate vicinity of the valve and for both flow rates tested, turbulence intensities and velocity gradients were higher in the minor outflow region than in the major outflow region. However, as the flow progressed downstream, the opposite was observed, with large peak velocity in the major outflow. The maximum shear stress across the St. Vincent valve occurred in the minor outflow region and increased from 30 to 60N/m² as the flow rate increased from 15 to 261/min. In the core of the larger jet, the shear stresses were very small (0–3N/m²). The flow at the edges of the jellyfish valve membrane, 10 mm (0.5D) downstream from the ring valve, consisted of two nearly symmetric jets in the vicinity of the tube wall. The maximum axial velocity in these jet regions increased from 1.7 to 2.5 m/s as the flow rates increased from 15 to 261/min. Pressure effects due to the oscillation of the membrane of the jellyfish valve appear to generate high shear stress in the immediate vicinity of the jellyfish valve (0.5D downstream). The values of shear stress were 0–27 N/m² for a flow of 151/min and 3–109 N/m² for a flow of 261/min. However, as the flow progresses downstream, shear stresses decay rapidly and return to the upstream undisturbed level at about 4D downstream, but at a slower rate than the RMS axial velocities. In general, for all operating flow conditions tested here, the jellyfish valve performed better than the St. Vincent valve when velocity and shear stress distributions are compared at locations more than 0.5D downstream from the valve.     

Protein synthesis in the gastrointestinal tissues of the ovine fetus

An isotope dilution procedure employing an 8h continuous infusion of L-[2,3,5,6-3H] tyrosine was used to determine fractional protein synthetic rates in the gastrointestinal tissues of ovine fetuses. The infusions were made into the inferior vena cava of the fetuses at 120-130 days of gestation. Immediately following the termination of the infusion the ewes were sacrificed and fetal tissues were collected, frozen in liquid nitrogen and stored at -20 C. The specific activity of the intracellular free and protein bound amino acid pools was determined from which the fractional synthetic rates (%/day) were calculated. These rates were as follows: reticulo-rumen, 49%; omasum, 10%; abomasum, 14%; proximal duodenum, 93%; and distal colon, 15%. The contribution of duodenum to the whole body protein synthesis was 10.5% while the contribution of the entire GIT (13.9%) was very close to that of liver (14.4%). The specific activity of tyrosine in the amniotic fluid and fetal ruminal fluid averaged 22% and 36% respectively of the specific activity in the plasma. The high turnover of tissue proteins in the fetal gastrointestinal tract as well as the presence of labelled tyrosine in the ruminal fluid indicate the functional importance of gastrointestinal activity in utero preparing the gastrointestinal tract for post-natal life.     

Electron-microscopic investigation of allografts and xenografts of the aortic valves after prolonged functioning in the human heart

An electron-microscopic investigation was made of allografts and xenografts of the aortic valves after various methods of chemical sterilization and γ-ray irradiation. Changes in the ultrastructural components were demonstrated in the cells of the valve grafts after chemical methods of sterilization, but the cells were intact after γ-ray irradiation. The dynamics of development of specific degeneration of the connective tissue of the valves during prolonged functioning of the grafts in the human heart was revealed. Degeneration of the collagen was shown not to be connected with its enzymic destruction, but to be the result of passive mechanical injury.