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961.
目的:以骨髓间充质干细胞作为种子细胞,探索组织工程化软骨的构建.方法:分离、获取、扩增骨髓间充质干细胞,通过将扩增的骨髓间充质干细胞接种于聚羟基乙酸(PGA)上,在成软骨诱导因子作用下在体外诱导培养3周后,将实验组和对照组的标本转植入自体兔腹腔内,进行体内培养6~12周后,再进行检测,评估工程化软骨的形成.结果:骨髓间充质干细胞接种于PGA支架上后,经过体外诱导培养和体内培养后,获得标本(7/10)出现软骨组织外观,进行组织学切片可见软骨陷窝,进行Ⅱ型胶原蛋白的免疫组化、Ⅱ型胶原mRNA原位杂交均为阳性.结论:兔骨髓间充质干细胞在成软骨诱导剂作用下,经体外和体内培养后,可生成组织工程化类软骨. 相似文献
962.
目的利用组织工程技术体外重建角膜上皮组织,为重建角膜表面提供良好的移植材料和方法。方法以等量凝血酶和纤维蛋白原作用生成的纤维蛋白胶为载体(实验组),种植兔角膜缘组织块,体外培养重建角膜上皮层,每天记录细胞生长覆盖面积,从生长特性、光镜特征、超微结构特点以及免疫细胞化学方面进行观察检测。结果角膜缘上皮细胞在纤维蛋白胶上黏附生长增殖,体外培养7d左右即形成单层上皮细胞,2周左右形成的复层上皮细胞与纤维蛋白胶构成角膜上皮组织经检测与生理状态下的角膜上皮组织相近。实验组与对照组(置盖玻片为载体)比较细胞生长覆盖面积第4天至第7天差异有显著性(P<0.05)。结论以纤维蛋白胶为载体,体外培养的角膜上皮组织片可作为眼表重建角膜上皮移植良好的来源。 相似文献
963.
A longitudinal model based on the simplex model is presented to analyze simultaneously means and covariance structure using univariate longitudinal twin data. The objective of the model is to decompose the mean trend into components which can be attributed to those genetic and environmental factors which give rise to phenotypic individual differences and a component of unknown constitution which does not involve individual differences. Illustrations are given using simulated data and repeatedly measured weight obtained in a sample of 82 female twin pairs on six occasions. 相似文献
964.
Akira Horiuchi Robin A Felder† 《Clinical and experimental pharmacology & physiology》1996,23(S3):150-154
1. In orefer to develop a simple, efficient system for the highlvel expression of dopamine recetors in eukaryotic cells, we have studied the effects of n-butyrate on the expression of rat D1A dopamine receptor cDNA in mouse fibroblast LTK- cells as compared with those of n-butyrate on endogenous D1 receptor levles in opossum kidney cells.
2. In the transfected LTK- cell mebranes with pRc/CMVD1A receptor cDNA, a selective D1 dopamine antagonist, [3 H]-SCH 23390, exhibited a Kd of 0.9 ± 0.1 nmol/L and a Bmax of 0.35 ± 0.05 pmol/mg protien (n = 5).
3. Addtion of n-butrate (2–10 mmol/L) to the culture medium for 48h dose-dependently increased the D1A receptor level up to 1.5 ± 0.3 pmol/mg protien (n = 7), although the Kd values were not affected. The increase in receptor level was accompanined by an elevation of selective D1 agoinist-induced adenyly cyclase activity.
4. In contrast, n-butyrate treatment (2–10 mmol/L) did not affect either endogenous D1 receptor levels or fendoldopmainduced adenylyl cyclase activity in possum kidney cells.
5. These results sugges n-butyrate is a sueful tool for obtaining high-level expression of D1A dopamine receptor cDNA in mouse fibroblast LTK- cells. 相似文献
2. In the transfected LTK- cell mebranes with pRc/CMVD
3. Addtion of n-butrate (2–10 mmol/L) to the culture medium for 48h dose-dependently increased the D
4. In contrast, n-butyrate treatment (2–10 mmol/L) did not affect either endogenous D
5. These results sugges n-butyrate is a sueful tool for obtaining high-level expression of D
965.
Transformation of human cells, both induced and spontaneous, is an extremely rare event, whereas rodent cells are relatively easily transformed when treated with a single carcinogenic agent. The present review addresses the question of why human cells are resistant to malignant transformation in vitro. To facilitate understanding of the problem, the process of transformation is divided operationally into two phases, i.e. phase I, immortalization; and phase II, malignant transformation. In human cells, one-phase transformation, i.e., the consecutive occurrence of phases I and II due to the action of a single carcinogenic agent, is observed only rarely. Once human cells are immortalized, however, malignant transformation by chemical carcinogens or oncogenes proceeds, suggesting that for human cells, phase I immortalization is a prerequisite for such transformation to take place. To date, about 20 papers have been published describing protocols for the two-phase transformation of a variety of human epithelial cells and fibroblasts. In most experiments, SV40, human papilloma viruses and their transforming genes are utilized for induction of phase I (immortalization) followed by the use of chemical carcinogens or activated oncogenes for induction of phase II (malignant transformation). Possible mechanisms that would render human cells refractory to transformation are discussed below. 相似文献
966.
浆细胞病患者IL-4产生细胞数减少的意义及机制探讨 总被引:2,自引:0,他引:2
本文运用APAAP法检测了16名浆细胞患者外周血细胞在PHA刺激下产生IL-4的能力。发现浆细胞病组阳性细胞比率明显低于正常对照组(P<0.001),且阳性细胞比率与患者血清中多克隆IgM、IgA水平呈正相关(r=0.806和r=0.703)。在正常人外周血中加入CRP50mg/L,经PHA刺激后IL-4产生细胞也明显减少。作者假设,由于IL-6增高引起CRP等急性期相蛋白大量分泌,使IL-4产生受到明显抑制,从而使B细胞激活发生障碍是浆细胞病中多克隆免疫球蛋白合成抑制的主要原因。 相似文献
967.
研究了苏乐康、绿茶提取物对~(60)钴γ射线和雌性激素联合诱发叙利亚金黄地鼠胚胎细胞恶性转化的抑制能力,并用脉冲辐解技术,对其抑制机制进行初步探讨。实验结果表明,苏乐康、绿茶提取物对γ射线和雌性激素联合诱发的金黄地鼠胚胎细胞恶性转化的抑制率分别为70.15%(P<0.05)和81.59%(P<0.05),它们的这种抑制能力与其清除超氧阴离子的能力有关, 相似文献
968.
健康成年金黄仓鼠腹腔内接种PVH-1(5×106pfu),FCM动态检测肝细胞DNA周期动力学变化,结果显示:PVH-1接种后处于G0+G1期的肝细胞与对照组动物相比无显著差异。S期肝细胞在第3天显著高于对照组动物(P<0.05),且在第7天时仍呈上升趋势,第14天到30天趋于正常水平。G2+M期肝细胞在PVH-1接种后第30天升高(P<0.05)。结果提示,动物在PVH-1接种后第3到第7天是病毒在肝细胞中的复制高峰,并阻滞仓鼠处于S期肝细胞分裂进入G2+M期,但是这种阻滞作用较短暂、并可逆,在PVH-1接种后14~30天自然消失。 相似文献
969.
An assessment of immunoreactive epidermal growth factor in urine of patients with urological diseases 总被引:1,自引:0,他引:1
N. H. Chow T. -S. Tzai P. -E. Cheng C. -J. Chang J. S. -N. Lin M. -J. Tang 《Urological research》1994,22(4):221-225
To examine the excretion of urinary epidermal growth factor (EGF) in urological diseases and the relationship of EGF urine levels with transitional cell carcinoma (TCC), we measured the concentration of EGF by radioimmunoassay. The series comprised patients with active TCC (n=50), others in tumor-free status (n=29) and with non-neoplastic inflammatory diseases (n=43), and normal controls (n=50). Urinary EGF values were lower in patients with urological diseases of different etiologies than in normal controls (P<0.005). Mean EGF levels of patients who had previous bladder tumor resection (n=21) were not statistically different from normal controls (P=0.2). For patients with active TCC, EGF urine levels showed a significant inverse relationship to increasing tumor grade (P=0.02). In addition, subjects who had received nephrectomy for pelvic carcinoma (n=8) showed significantly lower mean EGF values than those with intact kidneys (n=21), irrespective of sex (P<0.05). Immunostaining of EGF on non-neoplastic kidney (n=9) revealed reactivity in the distal convoluted tubules and thick ascending limbs of Henle. Our results suggest that the kidney is the major source of urinary EGF. Its excretion in urine is decreased in both inflammatory and neoplastic diseases of the urinary tract. EGF may play an important part in the biological activity of TCC. Further study is indicated to investigate the monitoring of EGF urine levels as a marker of recurrence for EGF receptor-positive TCC. 相似文献
970.
Renin-producing renal cell carcinomas—clinical and experimental investigations on a special form of renal hypertension 总被引:2,自引:0,他引:2
J. Steffens R. Bock H. U. Braedel E. Isenberg C. P. Bührle M. Ziegler 《Urological research》1992,20(2):111-115
Summary The pathogenetic relationship between tumour and hypertension was investigated in 129 patients with renal cell carcinoma, of whom 41 (31.8%) were hypertensive. Of these 41 patients with renal tumours and hypertension, 6 (14.6%) were found to have primary reninism. In these patients the plasma renin activity in blood from the renal veins showed a tumour kidney to contralateral kidney ratio of between 4 and 7, and 2 patients also had secondary hyperaldosteronism. In the same 6 cases the renin content in the renal tumour tissue was significantly higher than that in tissue from the adjacent tumour-free renal cortex of the ipsilateral kidney. Immunohistochemical demonstration of renin in the tumour was only possible in these 6 cases. In 5 of these patients blood pressure returned to normal following nephrectomy; in the 6th case there was a drop in blood pressure after nephrectomy. In 3 renin-positive tumours examined, autonomous renin production was demonstrated in cell culture. Renin-producing renal cell carcinomas are an uncommon cause of renal hypertension. The differential diagnosis of hypertension should therefore also include renal tumour. 相似文献