Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.25.1 (deoxyribonuclease)
 1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The three-dimensional ultrastructure of the rat mesangial matrix was studied in acellular rat renal cortex in comparison with intact cortex by scanning electron microscopy (SEM). The mesangial region was covered with fenestrated endothelial cells and was not identified in untreated specimens by SEM. Acellular renal cortex was obtained by perfusion with 4 mM EDTA, 3% Triton X-100, 0.0025% deoxyribonuclease in 1 M NaCl and 4% sodium deoxycholate. Transmission electron microscopy revealed that the glomerular basement membrane (GBM) and mesangial matrix maintained their respective shape and did not collapse even after removal of the cellular components. By SEM, the mesangial matrix appeared as fenestrated septa with oval or round stomata between the glomerular capillaries. The diameter of the stomata was 601 +/- 290 nm. The diameter of the fibrils forming the stomata was 177 +/- 80 nm. These fenestrated structures of the mesangial matrix appear to be useful in supporting glomerular tufts, in stretching and retracting mesangial cells and in passing macromolecules from the capillary lumen into the mesangium.
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PMID:Three-dimensional architecture of the mesangial matrix--comparison of the intact and acellular glomerulus. 261 15

Aldehyde-fixed rat tissues were variously dehydrated and impregnated in water-miscible 2-hydroxypropyl methacrylate (HPMA) containing 3 to 20 per cent water and 0.1 per cent alpha,alpha-azobisisobutyronitrile as catalyst for subsequent polymerization with ultraviolet light. Heat polymerization was also effective. Blocks of embedded tissue readily gave ultrathin sections, which required staining by uranyl acetate and/or lead stains to give adequate contrast for electron microscopy. The ultrastructure of pancreas, kidney, muscle, and intestine was well preserved by aldehyde fixation alone. Use of postfixation in osmium tetroxide or direct osmium tetroxide fixation was unsatisfactory. The fine structure of aldehyde-fixed liver from fasted rats was well preserved, whereas that from normal rats showed considerable disorganization and collapse, apparently because of extraction of glycogen during the embedding procedure. Enzymatic extraction of proteins by pepsin and of ribonucleic acid by ribonuclease after either formaldehyde or glutaraldehyde fixation was rapidly effected by direct treatment of ultrathin sections with solutions of the enzymes. In contrast, no digestion of chromatin by deoxyribonuclease could be detected. In spite of this present limitation, HPMA appears to have several advantages over earlier water-miscible embedding media for electron microscopy and to be particularly suitable for ultrastructural cytochemistry.
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PMID:Hydroxypropyl methacrylate, a new water-miscible embedding medium for electron microscopy. 585 16