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31.
David A. Smith John L. Glover Laurace E. Townsend Diane E. Maupin 《In vitro cellular & developmental biology. Animal》1991,27(12):914-920
Summary Myocardial cell culture methods are now well established for animal and fetal human tissue. We present here a method for harvesting
and culturing adult human atrial myocardiocytes. Cells are obtained from fresh atrial tissue normally discarded after being
removed to cannulate the right atrium during open heart surgery. The atrial tissue is minced and then digested using collagenase.
The single cell suspension is initially cultured in serum-containing growth medium, then transferred to defined medium, selective
for myocardial cell growth. The cells are characterized by immunoperoxidase stains and transmission electron microscopy. The
cultured cells stain positive for myoglobin, whereas control cultured fibroblasts and endothelial cells do not. Electron microscopy
shows the presence of numerous myofibrils, Z-bodies, pleomorphic mitochondria, and secretory granules. The chronological age
of the donor was an important factor in culturing the adult tissue, the younger tissue correlated with a higher success rate.
This method provides a means for in vitro study of human adult myocardial cells and provides guidelines for appropriate atrial
tissue to use. 相似文献
32.
33.
Synthesis and in vitro bioactivity of C-terminal deleted analogs of human growth hormone-releasing factor 总被引:4,自引:0,他引:4
N Ling A Baird W B Wehrenberg N Ueno T Munegumi P Brazeau 《Biochemical and biophysical research communications》1984,123(2):854-861
A series of C-terminal deleted analogs of human growth hormone-releasing factor (hGRF) with either an amidated or a free carboxylic acid C-terminus were synthesized by solid phase methodology. Their capacity to release growth hormone was tested on rat anterior pituitary cells in monolayer culture. A gradual decrease of bioactivity down to 23% relative to hGRF was noted when the C-terminal amino acids were deleted to hGRF (1-34)OH. Further deletions, however, did not decrease the bioactivity because the potencies of the fragments, hGRF(1-31)NH2, (1-30)NH2 and (1-29)NH2 remained at about 50% of that of hGRF. Continual deletion of residues to hGRF(1-23)NH2, (1-22)NH2 and (1-21)NH2 still yielded bioactive fragments with full intrinsic activity despite very low potency. Only with the deletion down to hGRF(1-19)NH2 did the bioactivity completely disappear. Thus, together with the data published in a previous paper (1), the minimal biologically active core of hGRF with full intrinsic activity comprises the fragment (3-21). 相似文献
34.
35.
A particle-induced X-ray emission (PIXE) analysis method is presented, which allows measurement of eight elements (i.e., K,
Ca, Mn, Fe, Cu, Zn, Se, and Rb) in human brain samples of only a few mg dry weight. The precision and accuracy of the method
were investigated by analyzing animal brain matter with both PIXE and instrumental neutron activation analysis (INAA). The
method was applied to measure the 8 elements in 46 different regions of 3 human brains. The sections analyzed originated from
either the left or the right cerebral hemisphere, brain stem, and cerebellum. For one of the brains, sections were also analyzed
from 26 corresponding regions of both hemispheres. For all elements, similar concentrations were found in the corresponding
areas of the left and right sides of the brain. The concentrations (in μg/g dry weight) of the elements K, Fe, Cu, Zn, Se,
and Rb were consistently higher in cortical structures than in white matter. Deep nuclei and brain stem, which have a mixed
composition, showed intermediate values for K, Zn, Se, and Rb. A hierarchical cluster analysis indicated that the various
brain regions clustered into two large groups, one comprising gray and mixed matter regions and the other, white and mixed
matter brain areas. 相似文献
36.
Apoferritin from horse spleen can be reversibly dissociated at pH 2 or in 7.2 M G-HCl (pH 3.5). Reconstitution of the native icositetramer in 0.1 M TEA buffer (pH 7.9) in the presence of 1 mM EDTA and 3 mM dithioerythritol leads to yields higher than 80%. To monitor the kinetic mechanism, intrinsic fluorescence, far-UV circular dichroism, and covalent cross-linking with glutaraldehyde were applied.The overall mechanism of assembly is characterized by a sequence of concentration-dependent association reactions involving structured monomers and a dimeric intermediate as the most prominent species, apart from trimers and dodecamers. The parallel decrease in monomers, dimers and trimers indicates that association equilibria precede the formation of the final assembly product.The assembly reaction is accompanied by characteristic changes in fluorescence emission and dichroic absorption. To a first approximation, renaturation and reassociation may be quantitatively described by one single rate-determining second-order process, subsequent to fast folding steps at the monomer level.Abbreviations CD
circular dichroism
- DTE
dithioerythritol
- G-HCl
guanidinium chloride
- SDS
sodium dodecylsulfate
- TEA
triethanolamine
- Tris
tris hydroxymethylamino methane
Dedicated to Professor Harold A. Scheraga on the occasion of his 65th birthday 相似文献
37.
The morphology of multivesicular bodies in soybean protoplasts and their role in endocytosis 总被引:1,自引:0,他引:1
Summary Multivesicular bodies (MVBs) in soybean protoplasts are distinct organelles (generally 250–500 nm in diameter) consisting of a limiting membrane and a number of smaller internal vesicles (generally 40–100 nm in diameter). MVBs of soybean protoplasts are morphologically similar to MVBs of animal cell systems. They can have tubular protuberances which extend from the main body of the organelle and a lamellar plaque on the cytoplasmic surface of their limiting membrane. In addition, the internal vesicles can be labeled by a zinc iodide-osmium tetroxide postfixation and may form via invagination of the limiting membrane.The MVBs of soybean protoplasts are a major compartment in the endocytotic pathway. They accumulate, over time, exogenously applied cationized ferritin and may deliver it to the major lysosomal or lytic compartment of the plant cell, namely, the vacuoles. 相似文献
38.
H. Schutkowski 《International Journal of Anthropology》1987,2(4):347-352
Facing the requirements of refined paleodemographical analyses, the access to the early ontogenetic sex ratio of skeletal
populations is an important feature. Using raw data provided byFazekas & Kosa (1978) for a sample of known sex, discriminant functions are derived from hip and thigh bone dimensions that allow an almost
unbiased classification of more than 70% of fetal and neonate individuals. 相似文献
39.
40.