吸入短寿命氡子体动物肺组织剂量与体重关系的探讨

本文介绍吸入短寿命氡子体的不同种动物肺组织吸收剂量与体重的关系。实验结果表明,吸收剂量随体重的增加而减小。     

~(141)CeO_2经气管内注入后在肺及淋巴结内的动态分布

本文报告了应用γ放射性测量和放射自显影方法,观察~(141)CeO_2经气管内注入后在大鼠肺及局部淋巴结中动态分布的特点。实验结果表明,~(141)Ce 在肺内与在不同部位、不同个体和单个淋巴结中的分布都是很不均匀的;其滞留量随时间而变化。     

NMR investigation of experimental chemical induced brain tumors in rats, potential of a superparamagnetic contrast agent (MD3) to improve diagnosis

The different steps of development of chemically induced brain tumors were investigated in rats by MRI using a superparamagnetic contrast agent, magnetite-dextran nanoparticles (MD3). Sprague-Dawley strain pregnant female rats were injected intravenously with ethynitrosourea solution at the end of pregnancy. Offspring whelped by the inoculated mother were followed. MRI examinations were performed at 0.5 T. MD3 nanoparticles were injected intravenously at a dose of 5 mg Fe kg^-1 body weight 30 min before rat sacrifice. After sacrifice, histological slices were stained with hematoxylin-eosin. Relaxation times were measured at 40 MHz and 37°. MD3 nanoparticles act differently according to the step of the tumor development. Before tumor appearance, at a step characterized by the presence of abnormal cell clusters, relaxation time T2 increased significantly. The T2-weighted image showed a small increase in signal intensity in the lesion. Image contrast was improved by MD3 nanoparticles injection because of the decrease in healthy tissue signal intensity. The Tl-weighted image did not provide any additional information. In presence of a minute tumor, relaxation times decreased in tumor but increased in surrounding tissue. The Tl-weighted image showed a hypersignal on the border of an hyposignal. T2-weighted image showed a hypersignal in the same area. Signal intensity was not modified after MD3 nanoparticles injection. When new vascular capillaries developed in the tumor, MD3 nanoparticles cross into the cerebral parenchyma. Transmission electron microscopy showed magnetite crystals in this specific area on cytoplasm vesicles of glial cells and in tumor-specific membrane arrangements. On T2-weighted image, the hypersignal consisted of a well defined part and a second more fuzzy part, its signal being extinguished after MD3 nanoparticles injection. Necrotic areas and edema can be discriminated. The use of such a superparamagnetic contrast agent would be helpful in early detection of tumor development and in improving distinction of tumor mass from its vascular environment in patients. © 1998 Elsevier Science B.V. All rights reserved.     

In Vitro Characterizations of PLLA/β-TCP Porous Matrix Materials and RMSC-PLLA-β-TCP Composite Scaffolds

To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissue engineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared by three steps, I.e. Solvent casting, compression molding and leaching stage. Factors influencing the compressive strength and the degradation behavior of the porous scaffold, e.g. Weight fraction of pore forming agent-sodium chloride (NaCl), weight ratio of PLLA: β-TCP, the particle size ofβ-TCP and the porosity, were discussed in details. Rat marrow stromal cells (RMSC) were incorporated into the composite by tissue engineering approach. Biological and osteogenesis potential of the composite scaffold were determined with MTT assay, alkaline phosphatase (ALP) activity and bone osteocalcin (OCN) content evaluation. Results show that PLLA/β-TCP bioactive porous scaffold has good mechanical and pore structure with adjustable compressive strength needed for surgery. RMSCs seeding on porous PLLA/β-TCP composite behaves good seeding efficacy, biocompatibility and osteoinductive potential. Osteoprogenitor cells could well penetrate into the material matrix and begin cell proliferation and osteogenic differentiation. Osseous matrix could be formed on the surface of the composite after culturing in vitro. It is expected that the PLLA/β-TCP porous composites are promising scaffolds for bone tissue engineering in prosthesis surgery.     

Immunomodulatory effect of mushrooms on cytotoxic activity and cytokine production of intestinal lamina propria leukocytes does not necessarily depend on β-glucan contents

We evaluated the effects of seven mushroom extracts (Grifola frondosa, Pholiota nameko, Panellus serotinus, Hypsizygus marmoreus, Pleurotus cornucopiae, Armillaria mellea, and Flammulina velutipes) on cytotoxic activity and cytokine production of lamina propria leukocytes (LPLs) isolated from rat small (S) and large (L) intestinal mucosa. Boiling water extracts from seven species of mushrooms showed no direct cytotoxicity against the YAC-1 target cells. However, prominent increases of cytotoxicity were observed in S- and L-LPLs co-cultured with P. serotinus extract. Cytokine production (TNFα, IFNγ, IL-12 p70, and IL-4) of S- and L-LPLs was stimulated in response to P. cornucopiae extract. Mushroom extracts contributed to target cell adhesion and/or cytokine production in the effector cells. The promotion of cytotoxic activity in S- and L-LPLs was not necessarily related to β-glucan content of the mushroom.     

复方芍根口服液防治放射性食管炎的实验研究

将Wistar大鼠随机分为7组:正常对照组,单纯照射组,复方芍根口服液正常剂量预防组(照后当天给药),复方芍根口服液大剂量预防组(照后当天给药),复方芍根口服液正常剂量治疗组(照后7天给药),复方芍根口服液大剂量治疗组(照后7天给药),西药治疗组(照后7天给药).用60Co γ射线一次性局部照射43 Gy诱导大鼠食管炎的发生,然后采用不同方式治疗.观察各组大鼠的饮食和饮水情况,体重变化情况;于照后14天处死大鼠,进行白细胞计数及分类,制作食管的组织病理切片,观察各组大鼠食管粘膜的组织病理改变及细胞器超微结构的改变情况.结果表明,复方芍根口服液及西药对食管的放射性病理损伤均有一定治疗作用.复方芍根口服液正常剂量预防组的细胞器恢复正常.复方芍根口服液预防、治疗组与单纯照射组相比饮食量和饮水量均增加,尤以中药大剂量预防组饮食、饮水量增加明显.西药治疗组与单纯照射组相比饮食量略下降,白细胞总数、淋巴细胞分类下降.复方芍根口服液各给药组与单纯照射组相比可提高淋巴细胞百分数.复方芍根中药口服液具有治疗放射性食管炎的作用,具有在临床推广的价值.     

大鼠放射性皮肤溃疡组织中c-Fos、Rb蛋白表达研究

为研究大鼠放射性溃疡组织中ｃ－Ｆｏｓ、Ｒｂ表达。采用１４０只Ｗｉｓｔａｒ大鼠进行局部照射（γ射线）制备放射性皮肤溃疡动物模型,观察病变１年,然后采用ｃ－Ｆｏｓ、Ｒｂ多克隆抗体及免疫组化方法检测溃疡组织中ｃ－Ｆｏｓ、Ｒｂ的表达情况。结果表明：ｃ－Ｆｏｓ、Ｒｂ的表达阳性率分别为４５．８％（３３／７２）、６３．９％（４６／７２）,两者阳性部位主要见于增生肥大的鳞状上皮细胞胞核、增生的间质成纤维细胞胞质及     

Long-Term Measures of Dyslipidemia,Inflammation, and Oxidative Stress in Rats Fed a High-Fat/High-Fructose Diet

Inflammation and oxidative stress are thought to be involved in, or associated with, the development of obesity, dyslipidemia, hepatic steatosis, and insulin resistance. This work was designed to determine the evolution of inflammation and oxidative stress during onset and progression of hepatic steatosis and glucose intolerance. Seventy-five male Wistar rats were divided to control and high-fat high-fructose (HFHFr) groups. A subgroup of each group was sacrificed at 4, 8, 12, 16, and 20 weeks. HFHFr-fed rats exhibited overweight, glucose intolerance, and hepatic steatosis with increased contents of hepatic diacylglycerols and ceramides. The HFHFr diet increased hepatic interleukin 6 (IL-6) protein and adipose tissue CCL5 gene expression and hepatic nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity but not mitochondrial reactive oxygen species (ROS) production. The HFHFr diet decreased plasma and liver levels of isoprostanoid metabolites as well as plasma thiobarbituric acid-reactive substance (TBARS) levels. Hepatic glutathione content was decreased with a moderate decrease in superoxide dismutase (SOD) and glutathione peroxidase (GPx) with the HFHFr diet. Overall, HFHFr diet led to hepatic lipid accumulation and glucose intolerance, which were accompanied by only moderate inflammation and oxidative stress. Most of these changes occurred at the same time and as early as 8 or 12 weeks of diet treatment. This implies that oxidative stress may be the result, not the cause, of these metabolic alterations, and suggests that marked hepatic oxidative stress should probably occur at the end of the steatotic stage to result in frank insulin resistance and steatohepatitis. These findings need to be further evaluated in other animal species as well as in human studies.