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Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
MeSH Review

Porosity

 
 
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Disease relevance of Porosity

  • Excessive production of cathepsin K induced osteopenia of metaphyseal trabecular bone and increased the porosity of diaphyseal cortical bone [1].
  • Radiopaque contrasting changes the morphology and reduces the porosity of the material but supports quick thrombus formation [2].
  • Nevertheless, increasing levels of fluoride were associated with bulkier bone, less porosity, and less mineral per unit of bone, which in direction though not degree suggested changes similar to those of osteomalacia and opposite from those of osteoporosis without apparent threshold [3].
  • We observed that both resting and stimulated (zymosan or phorbol-myristate acetate) production by C57BL/6 mouse phagocytes are significantly higher in granulomas induced with high porosity polyacrylamide beads (P300) than in those induced with beads of low polyacrylamide porosity (P4) [4].
  • The results suggest that the cariogenicity of dental plaque formed in the presence of sucrose cannot be attributed only to its higher porosity, but the lower inorganic concentration may also be important [5].
 

High impact information on Porosity

  • Geochemical models of melting at mid-ocean ridges-particularly those based on trace elements and uranium-decay-series isotopes-predict that melt segregates from the matrix at very low porosities, of order 0.1% [6].
  • Chronic exposure to ethanol reduces the porosity of the endothelium; this mechanism may underlie the hyperlipoproteinaemia observed in some people who drink heavily [7].
  • Increased fluid shear forces also resulted in the generation of a better spatially distributed extracellular matrix inside the porosity of the 3D titanium fiber mesh scaffolds [8].
  • We have analyzed the multimeric structure of factor VIII/von Willebrand factor in plasma by sodium dodecyl sulfate electrophoresis using gels of varying porosity and a discontinuous buffer system [9].
  • We conclude that histamine causes pulmonary vascular permeability to protein to increase but that the effects on exchanging vessel porosity are more modest than those suggested for systemic microvessels [10].
 

Chemical compound and disease context of Porosity

  • Porous hydroxyapatite (HA-P) discs (5 mm in diameter; 1.5 mm thick; porosity, 80%; mean pore size, 200 micron) were impregnated with purified bovine skin collagen (1 mg/disc) and a small amount of semipurified bone morphogenetic protein (BMP) of sarcoma origin (100 micrograms/disc) and implanted into dorsal muscles of ddY mice [11].
  • The diameter and porosity of sinusoidal endothelial fenestrations were increased in chronic ethanol-fed rats without liver fibrosis, however, they decreased within 4 weeks of the cessation of thioacetamide treatment [12].
  • CLINICAL RELEVANCE: The prevalence of fine concentric laminations having low porosity, and the common occurrence of apatite among struvite-containing urinary calculi from dogs may be 2 reasons why the efficacy of dietary and medicinal manipulations in dissolving urinary calculi is greater among cats than it is among dogs [13].
  • Neither differences in molybdenum concentration, nor in porosity of the samples, due to different production routes, had any influence on the toxicity of the materials [14].
 

Biological context of Porosity

  • In a separate group of patients (four pairs + one post biopsy) on concurrent treatment with tibolone, there was no significant increase in the osteon density, cortical porosity, median canal diameter, or the markers of bone formation and resorption [15].
  • Intracortical bone remodeling in the tibia was activated and cortical porosity increased by PTH [16].
  • It was proven that the proportion of residual silanol groups (which correlates with hydrophilicity), and the fraction of siloxane 6-rings (which correlates with porosity) may be tailored by adequate catalytic conditions, mostly by the hydrolysis pH [17].
  • DESIGN: Relationships among the number of teeth remaining (total, anterior, and posterior teeth), oral bone height, oral bone porosity, bone mineral density of the lumbar spine and the femoral neck, estrogen use status, and the duration of estrogen use were evaluated in 330 Japanese postmenopausal women (mean age +/- SD, 56.8 +/- 7.6 y) [18].
  • Consequently, it can be concluded that the release kinetics of gentamicin from bone cements is controlled by a combination of surface roughness and porosity [19].
 

Anatomical context of Porosity

  • Analysis of the properties of calcium-mediated gels formed from pectins containing HG domains with differing degrees and patterns of methyl-esterification indicated that HG with a non-blockwise pattern of methyl ester group distribution is likely to contribute distinct mechanical and porosity properties to the cell wall matrix [20].
  • This change was followed 2 weeks later by increased osteoclast number and cortical porosity, reduced trabecular and cortical width, and decreased spinal BMD and vertebral strength [21].
  • In osteopetrotic rats, the stapes consisted of 48.3% bone, 35.9% mineralized cartilage, and 15.9% porosity, while after CSF-1 treatment, the bone content increased to 55.2%, cartilage was decreased to 21.7%, and porosity increased to 23.0%, respectively [22].
  • With monolithic capillaries of higher porosity and fused-silica GC capillaries, the transmembrane flux effects are noticeable but still significantly smaller than with conventional PVC membranes [23].
  • Residual sodium hypochlorite within the porosities of mineralized dentin may result in incomplete resin polymerization, and hence compromised bond strength [24].
 

Associations of Porosity with chemical compounds

  • The extent of membrane porosity was assessed by both propidium iodide staining and lactate dehydrogenase leakage to assure that porosity was comparable between the cell groups [25].
  • These variations were in accordance with all previous clinical studies, suggesting that fractal evaluation of trabecular bone projection has real meaning in terms of porosity and connectivity of the 3D architecture [26].
  • We conclude that continuous administration of PTH and estrogen increases cortical porosity but has substantial beneficial effects on vertebral cancellous bone volume and cortical width in OVX rats [27].
  • In contrast, urea clearance decreased only slightly (approximately 1 to 2% per 10 reuses), albeit statistically significantly with reuse, regardless of the porosity of the membrane and reprocessing method [28].
  • In contrast, all the new bone was maintained in the PGE2 + 5 micrograms of Ris on/off group; (4) PGE2 + Ris cotreatment failed to block the increase in cortical bone porosity induced by PGE2; and (5) in the PGE2 alone and PGE2 + 1 microgram of Ris on/off groups bone turnover was higher than that in the PGE2 + 5 micrograms of Ris on/off group [29].
 

Gene context of Porosity

  • Krox-20-/- mice develop skeletal abnormalities including a reduced length and thickness of newly formed bones, a drastic reduction of calcified trabeculae and severe porosity [30].
  • The FGA 2224G > A SNP modulated the relation between plasma fibrinogen concentration and fibrin clot porosity [31].
  • Over 2 years of cyclical PTH therapy, cortical thickness remained significantly higher than controls (680 +/- 202 vs 552 +/- 218 microm, p < 0.05), without significant changes in cortical porosity [32].
  • By 18 weeks, mdx tibial cross-sectional area, cortical thickness, and porosity remained significantly less (p < 0.001) than normal [33].
  • The VEGF released from the mineralized and non-mineralized scaffolds was over 70% active for up to 12 days following mineralization treatment, and the growth of mineral had little effect on total scaffold porosity [34].
 

Analytical, diagnostic and therapeutic context of Porosity

  • The 175 kDa HA-binding subunit may be nonglobular (asymmetric), since its apparent size by SDS-PAGE is dependent on the polyacrylamide gel pore size; M(r) increases as porosity decreases [35].
  • In an effort to get better encapsulation efficiency and release rate, we have worked on the possibility of compressing the microspheres into discs and modifying the porosity of the discs by using biocompatible materials like polyethylene glycol (PEG) and calcium phosphates and also on the fabrication of double-walled and composite microspheres [36].
  • X-ray and scanning electron microscopy analyses were carried out to evaluate the nature of the new ceramic support in comparison with the most common commercial product; pore size distribution and porosity were controlled to known hydroxyapatite ceramic architecture for the different possible uses [37].
  • The polyurethane materials tested were: Vascugraft (fibrous, open pore structure); commercial Hydrophilic Mitrathane prosthesis (high porosity, smooth surface, non-permeable, closed pore structure); experimental hydrophobic Mitrathane (less porosity but a fibrous, open pore structure, similar to Vascugraft) [38].
  • In the second method, the immobilization reagents (at densities up to 50 mumol/ml) were directly copolymerized with acrylamide and bisacrylamide to form activated gels of the desired shape and porosity [39].

References

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  6. Melt retention and segregation beneath mid-ocean ridges. Faul, U.H. Nature (2001) [Pubmed]
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  21. Osteocyte apoptosis is induced by weightlessness in mice and precedes osteoclast recruitment and bone loss. Aguirre, J.I., Plotkin, L.I., Stewart, S.A., Weinstein, R.S., Parfitt, A.M., Manolagas, S.C., Bellido, T. J. Bone Miner. Res. (2006) [Pubmed]
  22. Auditory ossicle abnormalities and hearing loss in the toothless (osteopetrotic) mutation in the rat and their improvement after treatment with colony-stimulating factor-1. Aharinejad, S., Grossschmidt, K., Franz, P., Streicher, J., Nourani, F., MacKay, C.A., Firbas, W., Plenk, H., Marks, S.C. J. Bone Miner. Res. (1999) [Pubmed]
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