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)

Calcium and folic acid absorption were studied in 28 adult male epileptics on chronic anticonvulsant therapy. In 16 patients on diphenylhydantoin alone, calcium absorption was abnormal in 9. In 12 patients on both diphenylhydantoin and phenobarbital, calcium absorption was abnormal in 3 patients. Folic acid (3H-PGA) absorption was normal in all but one patient, while serum folate (less than 6.4 ng/ml) was reduced in all patients. Hypocalcemia (less than 8.5 mg/100 ml) occurred in only 2 patients, while serum alkaline phosphatase was elevated in 7 patients. These findings support the proposal that rickets and osteomalacia reported in patients on chronic anticonvulsant therapy results from reduced calcium absorption. The effect of these drugs appears to be the acceleration of the metabolism of vitamin D and an increase in the excretion of polar metabolites. This may result in reduced levels of 25-hydroxycholecalciferol and 1,25-dihydroxycholecalciferol which are necessary for normal absorption of calcium. Since calcium absorption may be impaired secondary to a relative vitamin D deficiency, a supplemental increase in vitamin D intake by patients on anticonvulsant drugs is recommended.
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PMID:Calcium and folic acid absorption in patients taking anticonvulsant drugs. 17 36

Sera containing the rare alkaline phosphatase-immunoglobulin G complex were studied to try to determine the type of interaction involved. Pepsin and papain digestion of immunoglobulin G showed that alkaline phosphatase was attached to the F(ab')2 region of the immunoglobulin molecule and not to the Fc region. Sialic acid did not play a role in this attachment. Attempts to generate the complex in vitro using polyclonal immunoglobulin, and attempts to dissociate the complex is an immune complex in vitro, were both unsuccessful. It is concluded that the complex is an immune complex formed by antibody-antigen reaction in the circulation, and consists of two molecules of monovalent alkaline phosphatase associated with one molecule of divalent immunoglobulin G.
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PMID:Site of alkaline phosphatase attachment in alkaline phosphatase-immunoglobulin G complexes. 678 2

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 syntheses and cytotoxic activities of substituted N-phenylacetamido derivatives of doxorubicin and melphalan are described. The derivatives were designed as prodrugs which could be activated in a site-specific manner by monoclonal antibody-penicillin-G amidase (mAb-PGA) conjugates. N-(Phenylacetamido)doxorubicin (2) and N-(phenylacetyl)melphalan (6) were found to be 10- and 20-fold less cytotoxic against H2981 lung adenocarcinoma cells than doxorubicin and melphalan, respectively. When incubated with PGA, the cytotoxicity of 2 and 6 increased and became equivalent to that of the corresponding drugs from which they were made. The poor solubility characteristics of 2 in aqueous solutions provided the basis for the development of the more soluble doxorubicin derivatives, N-(4-aminophenylacetyl)doxorubicin (3) and N-(4-phosphonooxy)phenylacetyl)-doxorubicin (4). In vitro cytotoxicity assays indicated that 3 and 4 were at least 1000-fold less toxic than doxorubicin against H2981 cells. PGA and the mAb conjugate L6-PGA were able to effect the activation of 3 and 6 on H2981 cells (L6-antigen positive). Hydrolysis of the phosphate group of 4 was required prior to activation with PGA or L6-PGA. This was achieved using alkaline phosphatase, or by exposing 4 to phosphatases present in cell culture medium. The activation of 3, 4, and 6 on H2981 cells by L6-PGA occurred in an immunologically specific manner, since activation could be blocked by saturating cell surface antigens with L6 prior to treatment with L6-PGA. These results demonstrate that 3, 4, and 6 are prodrugs that can be specifically activated to release clinically approved anticancer agents by a mAb-PGA conjugate.
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PMID:Prodrugs of doxorubicin and melphalan and their activation by a monoclonal antibody-penicillin-G amidase conjugate. 846 46

1. The effects of whole grains of wheat on the digestive tract of broiler chickens was studied. A complete pelleted feed was compared with free choice feeding of whole wheat and a pelleted protein concentrate, given from 7 to 29 d of age. 2. Pepsin activity in proventriculus tissue was lower in whole wheat-fed birds than in complete diet-fed birds. The weight (g/kg body weight) of the gizzard was higher in whole wheat-fed birds and its contents had a lower pH. 3. In the intestine, there were no differences in deoxyribonucleic acid (DNA) concentration, protein/DNA, ribonucleic acid (RNA)/DNA, RNA/protein ratios or alkaline phosphatase activity expressed per tissue weight. The weight (g/kg body weight) of the duodenum was lower in whole wheat-fed birds and its contents had a higher pH. Also the activities of alkaline phosphatase and leucine aminopeptidase in the duodenum, and maltase in the ileum, expressed per unit of bird weight, were lower in whole wheat-fed birds. 4. These results suggest that whole grain feeding increases the chemical (pepsin in proventriculus) and physical (gizzard muscle) functionality of the upper part of the digestive tract but decreases the digestive capacity of the intestine. Higher gizzard functionality may play a positive role in the control of bacterial populations. The lower digestive enzyme activities in the intestine may be detrimental in situations of mucosal deterioration caused by intestinal disease.
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PMID:Differences in the digestive tract characteristics of broiler chickens fed on complete pelleted diet or on whole wheat added to pelleted protein concentrate. 1282 14

The objective of this study is to enhance in vivo ectopic bone formation by combination of plasmid DNA impregnation into three-dimensional (3-D) cell scaffolds and a developed in vitro culture method. Gelatin was cationized by introducing spermine (Sm) to the carboxyl groups for complexation with the plasmid DNA. As the MSC scaffold, collagen sponge reinforced by incorporation of poly(glycolic acid) (PGA) fibers was used. A complex of the cationized gelatin and plasmid DNA of BMP-2 was impregnated into the scaffold. MCS were seeded into each scaffold and cultured by a static and perfusion methods. When MSC were cultured in the PGA-reinforced collagen sponge, the level of BMP-2 expression was significantly enhanced by the perfusion culture compared with static method. When the osteoinduction activity of the PGA-reinforced collagen sponges seeded with PBS, MSC, naked plasmid DNA-BMP-2, cationized gelatin-plasmid DNA-BMP-2 complex, and transfected MSC by static and perfusion method, were studied following the implantation into the back subcutis of rats in terms of histological and biochemical examinations, homogeneous bone formation was histologically observed throughout the sponges seeded with cationized gelatin-plasmid DNA of BMP-2 complex and transfected MSC by perfusion method, although the extent of bone formation was higher for the later one. The level of alkaline phosphatase activity and osteocalcin content at the implanted sites of sponges seeded with transfected MSC by perfusion method were significantly high compared with those seeded with other agents. We conclude that combination of plasmid DNA-impregnated PGA-reinforced collagen sponge and the perfusion method was promising to promote the in vitro gene expression for MSC and in vivo ectopic bone formation.
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PMID:Enhanced ectopic bone formation using a combination of plasmid DNA impregnation into 3-D scaffold and bioreactor perfusion culture. 1613 84

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

This article describes the development of an in vitro culture system to enhance the expression of a plasmid DNA for mesenchymal stem cells (MSCs) by a combination of plasmid DNA impregnation into three-dimensional cell scaffolds and culture methods. Gelatin was cationized by introducing spermine to the carboxyl groups for complexation with the plasmid DNA. As the MSC scaffold, poly(glycolic acid) (PGA) fiber fabrics, collagen sponges, and collagen sponges reinforced by incorporation of PGA fibers were used. A complex of cationized gelatin and plasmid DNA encoding bone morphogenetic protein 2 (BMP-2) was impregnated into the scaffolds. Plasmid DNA was released from PGA-reinforced collagen sponge for longer than from the other scaffolds. MCS were seeded into each type of scaffold and cultured by static, stirring, and perfusion methods. When MSCs were cultured in PGA-reinforced sponge, the level of BMP-2 expression was significantly enhanced by perfusion culture compared with the other culture methods, and the time of expression was prolonged. Irrespective of the culture method, the expression level was significantly higher from plasmid DNA impregnated in scaffold than by plasmid DNA in medium. The alkaline phosphatase activity and osteocalcin content of MSCs cultured in PGA-reinforced sponge by the perfusion method were significantly higher compared with those of other methods, and a significantly higher amount of plasmid DNA internalized into MSCs was observed. We conclude that a combination of plasmid DNA-impregnated PGA-reinforced sponge and the perfusion method was promising to promote in vitro gene expression for MSCs.
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PMID:Impregnation of plasmid DNA into three-dimensional scaffolds and medium perfusion enhance in vitro DNA expression of mesenchymal stem cells. 1625 1

The development of chemical reactions in nanospaces is of paramount importance for the development of active nanodevices, particularly in nanofluidics. It has been shown in a previous paper that phospholipid vesicles can be incorporated without spontaneous bilayer rupture into poly-L-glutamic acid/poly(allylamine) (PGA/PAH) multilayered polyelectrolyte films. The aim of the present study was to use such a system as an "embedded submicronic reactor" able to trigger precipitation of calcium phosphates within closed spaces through an enzymatic reaction, the enzyme also being encapsulated in the vesicle interior. To this aim, large unilamellar vesicles (LUVs) were produced containing calcium ions as active ions in the mineralization process, spermine as an activator of crystal growth, and alkaline phosphatase as a catalyst to convert phosphate esters into phosphates. After stabilization by adding a layer of poly-(D-lysine), these vesicles were embedded in a (PGA-PAH)n film. A paranitrophenyl phosphate containing solution was then put in contact with this film. It is shown by means of infrared spectroscopy in the attenuated total reflection mode that, consecutively to this contact, calcium phosphates are growing inside the embedded vesicles. By using scanning near-field fluorescence microscopy, it is demonstrated that the alkaline phosphatase enzymes are most probably located inside the vesicles after their embedding. In addition, atomic force microscopy was used to show, after chemical removal of the organic top layer of the film, that the inorganic platelets produced after the precipitation reaction are localized in volumes of similar size and shape as that of the vesicles into which the phosphate ester hydrolysis and subsequent precipitation reaction did occur.
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PMID:Layer-by-layer self-assembled polyelectrolyte multilayers with embedded liposomes: immobilized submicronic reactors for mineralization. 1648 29

Despite the widespread role of transforming growth factor-beta3 (TGFbeta3) in wound healing and tissue regeneration, its long-term controlled release has not been demonstrated. Here, we report microencapsulation of TGFbeta3 in poly-d-l-lactic-co-glycolic acid (PLGA) microspheres and determine its bioactivity. The release profiles of PLGA-encapsulated TGFbeta3 with 50:50 and 75:25 PLA:PGA ratios differed throughout the experimental period. To compare sterilization modalities of microspheres, bFGF was encapsulated in 50:50 PLGA microspheres and subjected to ethylene oxide (EO) gas, radio-frequency glow discharge (RFGD), or ultraviolet (UV) light. The release of bFGF was significantly attenuated by UV light, but not significantly altered by either EO or RFGD. To verify its bioactivity, TGFbeta3 (1.35 ng/mL) was control-released to the culture of human mesenchymal stem cells (hMSC) under induced osteogenic differentiation. Alkaline phosphatase staining intensity was markedly reduced 1 week after exposing hMSC-derived osteogenic cells to TGFbeta3. This was confirmed by lower alkaline phosphatase activity (2.25 +/- 0.57 mU/mL/ng DNA) than controls (TGFbeta3- free) at 5.8 +/- 0.9 mU/mL/ng DNA (p < 0.05). Control-released TGFbeta3 bioactivity was further confirmed by lack of significant differences in alkaline phosphatase upon direct addition of 1.35 ng/mL TGFbeta3 to cell culture (p > 0.05). These findings provide baseline data for potential uses of microencapsulated TGFbeta3 in wound healing and tissue-engineering applications.
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PMID:Sustained release of TGFbeta3 from PLGA microspheres and its effect on early osteogenic differentiation of human mesenchymal stem cells. 1657 87


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