Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic pyelonephritis was induced in young adult cats by the intravenous injection of a human or a feline strain of Escherichia coli after ligation of one ureter for 24 or 48 h. In the 3 cats infected with the feline strain, scarred kidneys from the obstructed side were removed at necropsy 3, 4 and 5 months later. Collagen was extracted from pyelonephritic and normal kidney tissue with dilute acetic acid and limited proteolysis with pepsin. Scarred kidneys gave higher yields of both acid-soluble collagen (normal = 0.57 +/- 0.12 mg per g tissue; scarred = 0.88 +/- 0.10 mg per g tissue) and pepsin-solubilized collagen (normal = 9.69 +/- 1.79 mg per g tissue; scarred = 20.02 +/- 2.84 mg per g tissue). There was no significant increase in the collagen yield from the kidneys of the 2 cats in which mild focal lesions were found 14 and 16 months after infection with the human strain of E. coli. Pepsin released collagens were separated by fractional salt precipitation and identified by agarose gel chromatography and polyacrylamide gel electrophoresis. Normal kidney was shown to contain collagen of Types I, IV and V (AB). The Type IV collagen extracted consisted of a mixture of 4 major pepsin-resistant chains of apparent molecular weights of 150 000, 115 000, 85 000 and 60 000. The collagen extracted from scarred kidneys was predominantly Type I, only trace amounts of Type IV and V components being present. These findings suggest that basement membrane collagens of the kidney are selectively degraded during the atrophy and scarring of chronic feline pyelonephritis and are preferentially replaced by interstitial Type I collagen.
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PMID:Experimental pyelonephritis in the cat: 3. Collagen alterations in renal fibrosis. 684 96

Rat osteoblasts were cultured on films of biodegradable poly(L-lactic acid) (PLLA), 75:25 poly(DL-lactic-co-glycolic acid) (PLGA), 50:50 PLGA, and poly(glycolic acid) (PGA) for up to 14 days. Osteoblasts attached equally well to all the polymer substrates after 8 h in culture. By day 4 in culture, osteoblasts had exceeded confluency numbers, and their proliferation leveled off by day 7. An increase in alkaline phosphatase (ALP) activity from 1.92 (+/- 0.47) x 10(-7) for day 7 to 5.75 (+/- 0.12) x 10(-7) mumol/cell per min for day 14 was reported for osteoblasts cultured on 75:25 PLGA, which was comparable to that observed for tissue culture polystyrene (TCPS) controls. The ALP activities expressed by osteoblasts cultured on PLLA, 50:50 PLGA, and PGA films did not significantly increase over time. Collagen synthesis for osteoblasts cultured on all polymer substrates was similar to that of TCPS and did not vary with time. The morphology of cultured osteoblasts was not affected by the continuous degradation of the polymer substrates. These results demonstrate that poly(alpha-hydroxy esters) can provide a suitable substrate for osteoblast culture and hold promise in bone regeneration by osteoblast transplantation.
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PMID:Osteoblast function on synthetic biodegradable polymers. 787 84

The collagen isotypes present at early (6 week) and late (5 month) stages of growing deer antler were isolated and identified. Pepsin-digested collagens were separated by differential salt fractionation, SDS-PAGE and Western blotting and subsequently identified by immunostaining. Cyanogen bromide digestion of antler tissue was used to establish a collagen type-specific pattern of peptides, and these were also identified by immunoblotting. Collagen type I was found to be the major collagen in both early- and late-stage antler. Collagen type II was present in the young antler in small amounts but was not confined to the soft "cartilaginous" tip of the antler. Collagen type XI was found in the pepsin digest of the young antler, but collagen type IX was not present at either stage of antler growth. Collagen type X was found in the young antler in all fractions studied. Microscopic study showed that the deer antler did not possess a discrete growth plate as found in endochondral bone growth. Unequivocal immunolocalization of the different collagen types in the antler were unsuccessful. These results show that, despite the presence in the antler of many cartilage collagens, growth does not occur through a simple endochondral process.
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PMID:Deer antler does not represent a typical endochondral growth system: immunoidentification of collagen type X but little collagen type II in growing antler tissue. 944 Feb 22

Osteoarthritis (OA) is a disorder which results in the destruction of the articular cartilage and the remodeling of the subchondral bone in synovial joints. We have analyzed the cartilage collagen from normal and osteoarthritic free-ranging rhesus monkeys from the Cayo Santiago colony. The cartilage samples were assigned a severity score based on histological staging system and were divided into four groups (normals, mild OA, moderate OA and severe OA). After a 4.0 M guanidinium chloride (GuCl) extraction, the remainder of the cartilage was digested with pepsin and the collagen was salt precipitated at 2.5 M and 4.3 M NaCl. The GuCl solubility of the osteoarthritic cartilage increased compared to normals. Collagen extractability by GuCl also increased with the severity of disease. Pepsin digestion followed by salt precipitation shows that collagen from rhesus osteoarthritis cartilage is more easily extracted than from normal cartilage. With an anti-type I collagen antibody we have detected the presence of type I collagen in the severe OA cartilage samples but not in the milder OA groups or in normal cartilage. Total collagen content decreases with severity of OA, which is not due to changes in propyl hydroxylation because examination of collagen hydroxylation, based on hydroxyproline analysis, shows no difference between OA and normal cartilage.
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PMID:Analysis of collagens solubilized from cartilage of normal and spontaneously osteoarthritic rhesus monkeys. 1155 Jul 7

We studied the effects of dexamethasone (Dex) and basic fibroblast growth factor (bFGF) on proliferation and differentiation of rat bone marrow stromal cells (RBMSCs), using three scaffolds: collagen sponge, poly(glycolic acid) (PGA)-collagen sponge, and PGA-collagen (UV) sponge. RBMSCs were seeded into the sponges, and cultured in primary medium, primary medium with Dex, and primary medium with bFGF and Dex. Three weeks after cultivation, we examined alkaline phosphatase (ALP) activity and cell number in the sponges, and also performed macroscopic, light microscopic, and scanning electron microscopic (SEM) observations. Collagen sponge shrank considerably, but PGA-collagen and PGA-collagen (UV) sponges maintained most of their original shape. PGA-collagen (UV) sponge supplemented with bFGF and Dex together had the highest ALP activity and cell number, followed by PGA-collagen sponge. Although collagen sponge showed cell proliferation only on the surface, the other two sponges showed cell proliferation in the interior. SEM showed the best cell attachment to PGA-collagen (UV) sponge in the presence of bFGF and Dex, followed by PGA-collagen sponge. In conclusion, PGA-collagen (UV) and PGA-collagen sponges proved to be much more useful as scaffolding for bone regeneration when combined with bFGF and Dex.
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PMID:Proliferation and differentiation of rat bone marrow stromal cells on poly(glycolic acid)-collagen sponge. 1625 90

Tooth loss accompanied by alveolar bone resorption presents a significant clinical problem. We have investigated the utility of a tissue-engineering approach to provide corrective therapies for tooth-bone loss. Hybrid tooth-bone tissues were bioengineered as follows. Tooth implants were generated from pig third molar tooth bud cells seeded onto polyglycolide (PGA) and polyglycolide-colactide (PLGA) scaffolds, and grown for 4 weeks in the omenta of adult rat hosts. Bone implants were generated from osteoblasts induced from bone marrow progenitor cells obtained from the same pig, seeded onto PLGA fused wafer scaffolds, and grown for 10 days in a rotational oxygen-permeable bioreactor system. The tooth and bone implants were harvested, sutured together, reimplanted, and grown in the omenta for an additional 8 weeks. Histological and immunohistochemical analyses of the excised hybrid tooth-bone constructs revealed the presence of tooth tissues, including primary and reparative dentin and enamel in the tooth portion of hybrid tooth-bone implants, and osteocalcin and bone sialoprotein-positive bone in the bone portion of hybrid tooth-bone constructs. Collagen type III-positive connective tissue resembling periodontal ligament and tooth root structures were present at the interface of bioengineered tooth and bone tissues. These results demonstrate the utility of a hybrid tooth-bone tissue-engineering approach for the eventual clinical treatment of tooth loss accompanied by alveolar bone resorption.
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PMID:Tissue-engineered hybrid tooth and bone. 1625 13

While the brain vasculature can be imaged with many methods, immunohistochemistry has distinct advantages due to its simplicity and applicability to archival tissue. However, immunohistochemical staining of the murine brain vasculature in aldehyde fixed tissue has proven elusive and inconsistent using current protocols. Here we investigated whether antigen retrieval methods could improve vascular staining in the adult mouse brain. We found that pepsin digestion prior to immunostaining unmasked widespread collagen IV staining of the cerebrovasculature in the adult mouse brain. Pepsin treatment also unmasked widespread vascular staining with laminin, but only marginally improved isolectin B4 staining and did not enhance vascular staining with fibronectin, perlecan or CD146. Collagen IV immunoperoxidase staining was easily combined with cresyl violet counterstaining making it suitable for stereological analyses of both vascular and neuronal parameters in the same tissue section. This method should be widely applicable for labeling the brain vasculature of the mouse in aldehyde fixed tissue from both normal and pathological states.
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PMID:Pepsin pretreatment allows collagen IV immunostaining of blood vessels in adult mouse brain. 1740 41

The objective of this study was to create a novel approach to promote bone induction through sustained release of growth factor from a 3-dimensional (3D) hybrid scaffold. Peptide-amphiphile (PA) was synthesized by standard solid-phase chemistry that ends with the alkylation of the NH2 terminus of the peptide. Collagen sponge was reinforced by incorporation of poly(glycolic acid) (PGA) fiber. A 3D network of nanofibers was formed by mixing basic fibroblast growth factor (bFGF) suspensions with dilute aqueous solutions of PA. A hybrid scaffold was fabricated by combination of self-assembled PA nanofibers and collagen sponge reinforced with incorporation of PGA fibers. The in vitro release profile of bFGF from hybrid scaffold was investigated, and ectopic bone formation induced by the released bFGF was assessed after subcutaneous implantation of hybrid scaffold into the backs of rats. Homogeneous bone formation was histologically observed throughout the hybrid scaffolds, in marked contrast to collagen sponge-incorporated bFGF. The level of alkaline phosphatase activity and osteocalcin content at the implanted sites of hybrid scaffolds were significantly high compared with collagen sponge incorporated with bFGF. The combination of bFGF incorporated in a collagen sponge self-assembled PA nanofiber hybrid scaffold is a promising procedure to improve bone regeneration.
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PMID:Bone regeneration on a collagen sponge self-assembled peptide-amphiphile nanofiber hybrid scaffold. 2655 49

In this study, we enhanced the expression of a plasmid DNA in mesenchymal stem cells (MSC) by the combination of three-dimensional (3D) tissue-engineered scaffold and nonviral gene carrier. To function as an enhanced delivery of plasmid DNA, acetic anhydride was reacted with polyethylenimine (PEI) to acetylate 80% of the primary and 20% of the secondary amines (PEI-Ac(80)). This acetylated PEI has been demonstrated to show enhanced gene-delivery efficiency over unmodified PEI. Collagen sponges reinforced by incorporating of poly(glycolic acid) (PGA) fibers were used as the scaffold material. DNA nanoparticles formed through simple mixing of plasmid DNA encoding bone morphogenetic protein-2 (BMP-2) and PEI-Ac(80) solutions were encapsulated within these scaffolds. MSC were seeded into each scaffold and cultured for several weeks. Within these scaffolds, the level of BMP-2 expression by transfected MSC was significantly enhanced compared to MSC transfected by DNA nanoparticles in solution (in 2D tissue culture plates). Homogeneous bone formation was histologically observed throughout the sponges seeded with transfected MSC by using DNA nanoparticles after subcutaneous implantation into the back of rats. The level of alkaline phosphatase activity and osteocalcin content at the implanted sites of sponges seeded with transfected MSC by using DNA nanoparticles were significantly higher when compared with those seeded with other agents.
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PMID:DNA nanoparticles encapsulated in 3D tissue-engineered scaffolds enhance osteogenic differentiation of mesenchymal stem cells. 1768 52

Collagen-fibronectin gels containing Bcl-2-transduced human umbilical vein endothelial cells (Bcl-2-HUVEC) implanted in the abdominal walls of immunodeficient mice form mature microvessels invested by host-derived smooth muscle cells (SMC) by 8 weeks. We tested the hypothesis that coengraftment of human aortic SMC (HASMC) could accelerate vessel maturation. To prevent SMC-mediated gel contraction, we polymerized the gel within a nonwoven poly(glycolic acid) (PGA) scaffold. Implanted grafts were evaluated at 15, 30, and 60 days. Acellular PGA-supported protein gels elicited a macrophage-rich foreign body reaction and transient host angiogenic response. When transplanted alone, HASMC tightly associated with the fibers of the scaffold and incorporated into the walls of angiogenic mouse microvessels, preventing their regression. When transplanted alone in PGA-supported gels, Bcl-2-HUVEC retained the ability to form microvessels invested by mouse SMC. Interestingly, grafts containing both Bcl-2-HUVEC and HASMC displayed greater numbers of smooth muscle alpha-actin-expressing cells associated with human EC-lined arteriole-like microvessels at all times examined and showed a significant increase in the number of larger caliber microvessels at 60 days. We conclude that SMC coengraftment can accelerate vessel development by EC and promote arteriolization. This strategy of EC-SMC coengraftment in PGA-supported protein gels may have broader application for perfusing bioengineered tissues.
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PMID:Human aortic smooth muscle cells promote arteriole formation by coengrafted endothelial cells. 1862 Apr 81


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