Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The development of rat transitional epithelial cells grown on conventional non-permeable surfaces was compared with development on permeable collagen supports. On glass or plastic surfaces, cells grew as expanding nomolayer sheets. Once confluent, growth continued with a bilayer being formed in most areas and apical cells being continuously sloughed off. Although most cells were interconnected by desmosomes, and junctional complexes were formed, no other indications of differentiation were observed. After 2-3 wk of growth, division stopped and cel death ensued. In contrast, single-cell suspensions plated on collagen-coated nylon disks reassociated into multicellular islands and commenced growth. Mitoses were confined to the basal cells in contact with the permeable substrate. The islands developed into epithelial trilayers, tapering to monolayers along spreading edges. Once the islands were confluent, stratification was completed and appeared similar to that observed in vivo. Germinal cells formed a basal lamina, and the upper layer was composed of large, flattened cells with an unusually thick asymmetrical plasma membrane on the apical surface. Electron microscopic and radioactive tracers demonstrated "leaky" zonulae occludentes with a restricted permeability to small molecules. The movement of urea was retarded in comparison to water. Unlike the slow turnover of adult epithelium in vivo, maturation and sloughing of apical cells were measurable. Transfer of cells could be effected and growth maintained for up to 4 mo. These results may indicate the necessity of a nutrient-permeable growth surface for the polarized differentiation of adult transitional epithelium.
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PMID:The growth and differentiation of transitional epithelium in vitro. 57 72

The degree of fibrosis and the pattern of collagen distribution in the acinar zone 3, as well as the thickness of the terminal hepatic vein walls (THV) were analyzed in 48 consecutive liver needle biopsies from 48 alcoholics with preserved liver architecture. The fibrosis occurred to more or less the same degree in the whole circumference of each THV. A positive correlation was found between the degrees of perisinusoidal/pericellular fibrosis (PSF) and the occurrence of incomplete or complete septa. The thickness of THV walls (TTHV) varied from 1.0-12.5 microns with a median of 3.9 microns. No relationship was found between TTHV and PSF. The results were compared to similar data obtained in liver biopsies from 117 non-alcoholics with normal morphology or slight non-specific changes. No significant difference concerning TTHV and THV diameter was found between alcoholic and non-alcoholic patients. The results suggest that the initial liver fibrosis in alcoholics is slightly asymmetrical distributed in each acinar zone 3 area. With progression, the fibrosis tends to be more uniformly distributed and septa appear, eventually linking THV with portal tracts. Apparently, thickening of the THV walls does not occur in early alcoholic liver disease.
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PMID:The pattern of fibrosis in the acinar zone 3 areas in early alcoholic liver disease. 170 42

The main purpose of this work was to identify the macromolecules carrying the surface charge of endothelial cells. This was done by measuring changes in cell electrophoretic mobility caused by enzymatic removal of glycocalyx components. Endothelial cells were removed from the bovine pulmonary artery using nonenzymatic procedures, plated, and identified by immunocytochemical methods and electron microscopy. Cultured cells were suspended in saline and placed in the lumen of a capillary in a Rank Brothers electrophoresis instrument. Voltage was applied between the ends of the capillary, and the velocity acquired by the cells was measured with a microscope. Preincubating the cells in protein-free saline for 1 h reduced the mobility by 25%. This reflects the loss of proteoheparan sulfate from the cell surface. Cell mobility was totally suppressed by exposing the entire cell surface to chondroitin sulfate lyase, but it was only slightly diminished when the enzyme was applied only to the cell side facing the culture medium. A partial decrease in mobility was obtained after enzymatic removal of either heparin, heparan sulfate, or collagen. The results indicate that sulfated glycosaminoglycans are the main carriers of the surface change in vascular endothelial cells. The asymmetrical effect of chondroitinase on the two sides of the cell indicates a distribution polarization for glycosaminoglycans in endothelial cells.
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PMID:Enzymatic lysis of sulfated glycosaminoglycans reduces the electrophoretic mobility of vascular endothelial cells. 210 36

Collagen genes col-6, col-7 (partial), col-8, col-14 and col-19 from the nematode Caenorhabditis elegans were sequenced, and compared to the previously sequenced genes col-1 and col-2. The genes are between 1.0 and 1.2 kb in length, and each includes one or two short introns. The presumptive promoter regions contain sequences similar to the eukaryotic TATA promoter element. Two distinct, conserved sequences were found in the presumptive promoter regions of, respectively, the dauer larva-specific genes col-2 and col-6, and the primarily adult-specific genes col-7 and col-19. The domain structures of the collagen polypeptides are similar: each polypeptide contains two triple-helix forming (Gly-X-Y)n domains, one of 30-33 amino acids (aa), and the other of 127-132 aa. The latter domain is interrupted by one to three short (2-8 aa) non-(Gly-X-Y)n segments that occur at relatively conserved locations in each polypeptide. Sets of cysteine residues flank the (Gly-X-Y)n domains in all of the polypeptides. The genes can be placed into three families based upon amino acid sequence similarities. Genes within a family do not always exhibit similar developmental expression programs, suggesting that structural and regulatory regions of the genes have evolved separately. The codon usage in the genes is highly asymmetrical, with adenine appearing in the third position of 85% of the glycine codons, and 93% of the proline codons.
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PMID:Sequence comparisons of developmentally regulated collagen genes of Caenorhabditis elegans. 275 56

The three-dimensional morphology of the surface of myelinated nerve fibres in the mouse sciatic nerve was studied by scanning electron microscopy after combined potassium hydroxide treatment and collagenase digestion (to remove the surrounding collagen fibrils and basal laminae from nerve fibres) as well as by transmission electron microscopy. The myelinated nerve fibre appeared as a long cylinder with sporadic annular constrictions corresponding to the nodes of Ranvier. Slight swellings of the surface due to Schwann cell nuclei were usually found at the middle of each internode. The surface of the nerve fibre clearly exhibited a network of bulges, which consisted of longitudinal bands extending from the nuclear swelling to the nodes of Ranvier through the internode, and transverse trabeculae bridging between these longitudinal bands. These bulges on the surface of nerve fibres were the site of the retained Schwann cell cytoplasm external to the myelin lamellae. These cytoplasmic networks on myelinated fibres presumably corresponded to the networks described by Cajal following silver impregnation. In addition, other thin elevations and focal round swellings were also found associated with these longitudinal bands and transverse trabeculae. These networks of Schwann cell cytoplasm are considered to be cytoplasmic channels for nutrition. The two apposing paranodal bulbs of nodes of Ranvier were often asymmetrical in their structure. The networks of the paranodal region were more complicated than those in the internode. The networks of Schwann cell cytoplasm converged into a continuous circumferential collar toward the node, which in turn gave rise to finger-like projections into the nodal gap.
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PMID:Scanning electron microscopic studies of the myelinated nerve fibres of the mouse sciatic nerve with special reference to the Schwann cell cytoplasmic network external to the myelin sheath. 345 Jul 86

The purpose of this study was to compare four different methods of microsurgical arterial anastomosis. One hundred and sixty rabbit popliteal artery anastomoses were performed. The following techniques were employed in each of four equal groups. Group 1: end-to-end technique with asymmetrical sleeving of the adventitia; Group 2: end-to-end technique with symmetrical sleeving of the adventitia and wrapping of the suture site with a collagen cuff; Group 3: end-to-end technique with symmetrical trimming of the adventitia; Group 4: end-in-end (sleeve) technique. A fifth group served as the control and omitted the division and anastomosis of the vessel. At one hour, 24 hr, three days, seven days, two weeks, six weeks, three months, and six months, the anastomosis was re-examined, and arterial segments were excised and prepared for evaluation. Long-term patency rates for the above techniques were found within the range of 87.5 to 92.5 percent. The healing process of anastomosed arteries occurred within three to seven days. A different pattern of arterial wall healing was found in the end-in-end, compared to the end-to-end, techniques. The study showed that the end-in-end technique is comparable in long-term patency rates to the conventional end-to-end technique, with significant reduction of the time needed to perform the anastomosis.
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PMID:Evaluation of different microsurgical techniques for arterial anastomosis of vessels of diameter less than one millimeter. 365 57

The theoretical analysis of the distribution on both sides of a flat porous membrane of the product generated by an enzyme covalently bound only on to one side of the membrane separating two compartments of widely different volumes is presented. Contrary to what occurs with heterogeneous symmetric systems, the diffusional limitations at the enzyme level play a prominent role, not only on the apparent enzyme activity, but also on product flux-splitting. The mathematical model developed shows that it is possible to concentrate the reaction product in the compartment opposite to that where the reaction occurs. The influence of the parameters and of the physical characteristics of an asymmetrical system on product distribution is analysed. This theoretical analysis is in excellent agreement with experimental data obtained with glucose oxidase immobilized on a porous collagen membrane.
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PMID:Vectorial product concentration obtained with a permeable immobilized enzyme membrane. A new approach to the analysis of biological transport systems. 375 38

Guinea pig gastric mucous epithelial cells were isolated, enriched, cultured in collagen cups, and put into Ussing chambers for electrophysiological studies. The cultured mucous cell monolayers, which retain the morphology of surface cells found in the intact tissue, had a maximal resistance (R) of 272 +/- 12 omega X cm2 and a potential difference (PD) of -3.8 +/- 0.4 mV (apical negative) between 4 and 10 days later (n = 33). The current-voltage and conductance-concentration relationships of the cultures were both nonlinear (n = 12). In addition, NaCl concentration gradients across the monolayer also gave asymmetrical and nonlinear dilution potentials, with the side of lower chemical potential always becoming electrically negative (n = 10). Calculation of the average Cl(-)-to-Na+ permeability ratio at pH 7.4 was 1.35, indicating a slightly greater conductance of anions over cations. Amiloride (0.1-1.0 microM) had no effect on PD or R when given from the apical or basal side (n = 18), but at higher concentrations (0.1-1.0 mM) there was a decrease in the PD. 4,4'-Diisothiocyanostilbene-2,2'-disulfonic acid at 10(-4) M increased R from the apical side only (n = 14), and acetazolamide at 5 X 10(-4) M reduced the PD to -0.5 mV (n = 8). Only ouabain at 10(-4) M from the serosal side was effective in reducing the monolayer PD to zero. This culture preparation will prove useful for future studies in determining specific functions for this gastric cell type and how those functions relate to barrier function in the stomach.
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PMID:Transepithelial transport of guinea pig gastric mucous cell monolayers. 390 78

Major components of basement membranes, including collagen IV, laminin, heparan sulphate proteoglycan and nidogen, were isolated from the matrix of the EHS sarcoma. The purified components were analysed for their domain structure and for the participation of distinct domains in molecular interactions and cell binding. Collagen IV consists of four domains which have triple helical or non-collagenous structures. Self-assembly of the protein into a network-like organization occurs by specific interactions between N-terminal triple helical segments and between the C-terminal globules. Cell binding requires a central triple helical segment. Laminin has the shape of an asymmetrical cross; different globular domains within this structure mediate binding to proteoglycan and to cells. The proteoglycan consists of four heparan sulphate chains attached to a small protein core. These chains have the potential to bind laminin, fibronectin and collagen IV. Nidogen was isolated in several molecular forms which showed either self-aggregation or binding to laminin.
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PMID:Laminin, proteoglycan, nidogen and collagen IV: structural models and molecular interactions. 644 Jul 57

Our study of experimental contracture in rats confirms the existence in laboratory animals of a phenomenon very much like human capsule contracture. The ultrastructural features of capsules in rats are essentially identical to those for humans and rabbits. Macrophages with silicon-containing material were present. Star-shaped myofibroblasts with extended processes appeared in contracted and noncontracted capsules. The myofibroblasts contained bundles of 60 to 80 A microfilaments with included dense bodies, convoluted nuclei, and extensive peripheral vesiculation. The myofibroblasts tended to be associated with more extensive ground substance and smaller diameter extracellular fibrils than were normal synthetic fibroblasts. The incidence of contracture was similar for implants beneath different amounts of overlying soft tissue dorsally and sternally, while compressibility and subjective softness were greater for implants beneath lesser amounts of overlying tissue. A greater mass of capsule formed beneath the heavier covering, however, suggesting that in clinical experience, cosmetically more acceptable results from submuscular prosthesis placement are probably due to a padding effect. Capsule glycosaminoglycans were primarily hyaluronic acid and dermatan sulfate. The occurrence of myofibroblasts in these capsules at a relatively late period (26 weeks) implicates myofibroblasts in the contracture mechanism, but details are still unknown. Contracture is a property of the capsule tissue; preliminary observations suggest that its occurrence is independent of species, anatomical site, surgical procedure, presence of extruded gel, presence of myofibroblasts, capsule thickness, or protein, collagen, or glycosaminoglycan composition. Cells within the capsule were geometrically asymmetrical, being extremely flattened in the plane parallel to the prosthesis surface.
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PMID:Effect of implant location on compressibility and capsule formation around miniprostheses in rats, and experimental capsule contracture. 719 80


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