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1.
Summary Our purpose was to engineer three-dimensional skeletal muscle tissue constructs from primary cultures of adult rat myogenic precursor cells, and to measure their excitability and isometric contractile properties. The constructs, termed myooids, were muscle-like in appearance, excitability, and contractile function. The myooids were 12 mm long and ranged in diameter from 0.1 to 1 mm. The myooids were engineered with synthetic tendons at each end to permit the measurement of isometric contractile properties. Within each myooid the myotubes and fibroblasts were supported by an extracellular matrix generated by the cells themselves, and did not require a preexisting scaffold to define the size, shape, and general mechanical properties of the resulting structure. Once formed, the myooids contracted spontaneously at approximately 1 Hz, with peak-to-peak force amplitudes ranging from 3 to 30 μN. When stimulated electrically the myooids contracted to produce force. The myooids (n=14) had the following mean values: diameter of 0.49 mm, rheobase of 1.0 V/mm, chronaxie of 0.45 ms, twitch force of 215 μN, maximum isometric force of 440 μN, resting baseline force of 181 μN, and specific force of 2.9kN/m2. The mean specific force was approximately 1% of the specific force generated by control adult rat muscle. Based on the functional data, the myotubes in the myooids appear to remain arrested in an early developmental state due to the absence of signals to promote expression of adult myosin isoforms.  相似文献
2.
赤链蛇毒器的发现及离体毒腺的产毒量   总被引:3,自引:3,他引:0  
吴卯斌 《蛇志》1996,8(1):15-17
本文通过对安徽黄山产赤链蛇毒器的解剖,描述了其毒器的形态、大小和着生位置,并测定了离体毒腺的产毒量。  相似文献
3.
The oxygen distribution in various bio-hybrid systems composed of cellular tissue on an artificial scaffold was estimated by mathematically modeling the oxygen consumption and diffusion. Mathematical models were established for practical systems such as bio-hybrid artificial liver (BAL) and bio-hybrid blood vessels, and the calculated results were compared with corresponding experimental data. Analysis of a spherical organoid (“spheroid”) composed of hepatic cells suggested that the oxygen consumption rate in hepatocyte spheroids incubated in a BAL is one or two orders of magnitude larger than the total average value that had been calculated for various organs. A model was established for a BAL system on a scaffold of commercially available hollow fiber (typical inner and outer radii of 150 and 200 μm) to determine the optimal conditions under which the hepatocytes can be packed as closely as possible into the hollow fiber lumen while still maintaining viability without falling into oxygen deficiency. A model of bio-hybrid blood vessels formed by vascular endothelial cells incubated on the inner wall of a hollow fiber scaffold was used to estimate the maximum thickness of viable endothelial tissue under various conditions of outer partial oxygen pressure and different sizes and permeabilities of the hollow fiber scaffold. The model suggested that the oxygen supply becomes quite restricted when the hollow fiber membrane is thicker than 100 μm; the thickness of the endothelium in a 500 μm-thick hollow fiber membrane was estimated to be 7 μm at most, even when the membrane permeability was as large as that of the culture medium.  相似文献
4.
水赤链游蛇毒器的解剖及离体达氏腺的产毒量   总被引:1,自引:1,他引:0  
王亦民 《蛇志》1997,9(2):11-12
通过对安徽黄山水赤链游蛇毒器的解剖,描述了其毒器的形态、大小和着生位置,并测定了离体毒腺的产量.  相似文献
5.
Bioreactors for 3-dimensional high-density culture of human cells   总被引:1,自引:0,他引:1  
Matsuura T 《Human cell》2006,19(1):11-16
A bioreactor was developed as an instrument to culture human or animal cells that require attachment in a large quantity or at a high density. The purpose for developing such a bioreactor is two-fold: to produce a large quantity of animal or human cells that have been modified by gene recombination technology to accommodate manufacture of physiologically-active substances or human proteins on an industrial scale; and for research to culture animal cells to form a high-density 3-dimensional structure as a morphological or functional tissue or organ entity. In the current report, the circulatory flow bioreactor and radial flow bioreactor (RFB) are introduced, in which the former can be scaled up. As a small bioreactor produced for the latter purpose, a rotary cell culture system and novel multicoaxial hollow-fiber bioreactor are introduced. Finally, a small RFB culture system that was scaled down by the present author and his collaborators for the study of a 3-dimensional high density culture system is described. The RFB can be readily scaled up for manufacturing or scaled down for research purposes. This is a cell culturing system that can induce the functions of human tissues by preparing a high density 3-dimensional organization of cells of human origin.  相似文献
6.
Summary Twenty to twenty-two days postcoitum mouse fetal pancreas organ bits were cultured on the dermal surface of irradiated pigskin as a substrate. The medium used for long term culture consisted of Eagle’s Minimum Essential Medium with the addition of 10% bovine serum, 0.02 U/ml insulin, 0.025 μg/ml glucagon, 3.63 μg/ml hydrocortisone, 100 μg/ml soybean trypsin inhibitor or 10−8 M atropine. When the medium lacked trypsin inhibitor or atropine but contained the three hormones, the pigskin support began to be destroyed after 2 to 4 wk in culture. Thereafter, the cultured cells could not grow and survive on the digested pigskin. When 10−6 M atropine was added to the medium, amylase secretion from cultured cells and destruction of pigskin were inhibited completely but pancreas cells could not grow or survive. In contrast, 100 μg/ml soybean trypsin inhibitor or 10−8 M atropine permitted cell growth, permitted amylase secretion from the cultured acinar cells, and prevented the destruction of pigskin. Under these conditions pancreas cells migrated or grew or both from the organ bits onto the surface of the pigskin dermis and organoid aggregations formed. Hydrocortisone was needed to permit growth for more than 2 wk. Glucagon and insulin had additive effects. Light and electron microscopic observations indicated the culture of at least five kinds of cells, i.e., duct, acinar, centroacinar, endocrine, and mesenchymal. The majority of cultured cells were duct cells and acinar cells. There were few mesenchymal cells. Mouse pancreas cells were cultured for at least 12 wk by this method. This investigation was supported by PHS Grant CA 30220 awarded by the National Cancer Institute, DHHS, Grant 1203M awarded by the Council for Tobacco Research, Inc., and Grant RD-65 (for equipment) awarded by the American Cancer Society. Nude mice were provided by Dr. Wendall M. Farrow of Life Sciences, Inc., Resource Laboratory N01, CP6-1005 of the National Cancer Institute.  相似文献
7.
We have screened primary cultures of human prostate for the expression of markers reported to be characteristic of specific cell lineages in vivo, in order to ascertain whether human prostate cells in vitro maintain and reflect their in vivo differentiated phenotypes and to evaluate the homogeneity of the populations of cells that can be derived from this tissue. Using single and dual stain immunofluorescent microscopy to analyse very early organoid and subsequently derived monolayer stage cultures, we have observed that expression of markers characteristic of human prostate epithelial cells in vivo is deregulated within 48h, indicating that dissociation of human prostate tissue and cultivation of prostate epithelial cells in culture can result in promiscuous expression of cell type specific markers of prostate epithelial cells. These observations have important implications for studies of cell lineage and differentiation of prostate cells in vitro.  相似文献
8.
9.
Summary In the present study we describe a new method to cultivate human tumors, which allows organoid differentiation under in vitro conditions. Diverse tumors of different origin and various histopathology which had been heterotransplanted to athymic mice were dissociated into single cells and seeded at high cell density onto a membrane filter consisting of cellulose nitrate at the gas-medium interface. Within a few days, the tumor cells reorganized and differentiated into organoid structures which exhibited the typical histological characteristics of the original tissues. Due to the formation of organoid aggregates, which was also previously seen with normal fetal cells, this type of culture has been described as organoid culture. In the case of adenocarcinomas of the lung and the colon including the rectum, glandular structures with central lumina, adjacent microvilli, and junctional complexes were formed. Numerous specific intercellular contacts such as desmosomes and tight junctions occurred as well as interdigitations of adjacent cell membranes. In a tumor of the rectum, a typical brush border differentiated at the surface of the reorganized tumor-tissue aggregate. Epidermoid carcinomas of the head and neck developed structures resembling the spinous layer of the epidermis, exhibiting numerous desmosomes and intracytoplasmic bundles of tonofilaments radiating into the desmosomes. Most tumors produced a fragmentary monolayered or multilayered basal lamina of similar morphological appearance as under in vivo conditions. These results illustrate the organoid reorganization and differentiation of human tumor cells under the experimentally rather simple conditions of the organoid culture systems and clearly demonstrate that this in vitro system comes close to the in vivo situation as far as certain differentiation phenomena are concerned.  相似文献
10.
Summary Various patterns of mineralization are found in the organism during fetal and postnatal development. Different findings and theories have been published in the literature with regard to the mechanisms of mineralization, many of which are controversely discussed. In the present study the different patterns of mineralization observed in the organoid culture system of fetal rat calvarial cells were investigated by electron microscopy. In organoid culture, calvarial cells grow and differentiate at high density, and deposition of osteoid and mineralization of the matrix occur to a very high extent. Different types of mineralization could be observed more or less simultaneously. It was found that hydroxyapatite crystals were formed at collagen fibrils as well as in the interfibrillar space. Mineralization was frequently seen in necrotic cells and cellular remnants as well as in extra-and intracellular vesicles. Addition of bone or dentin matrices or the artificial hydroxyapatite Interpore 200 to the cells caused an increased mineralization in the vicinity and on the surface of the matrices with and without participation of collagen. On previously formed mineralized nodules, an apposition of mineralizing material appeared due to matrix secretion by osteoblasts. It is concluded that initiation of mineralization occurs-at least in vitro-at every nucleation point under appropriate conditions. These mineralization foci enlarge by further apposition as well as by cellular secretion of a mineralizing matrix. Furthermore, cell necroses may liberate mineralizable vesicles. All these patterns of mineralization are the result of different activities of one cell type.  相似文献
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