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Sample records for growth factor release

  1. Sulodexide induces hepatocyte growth factor release in humans.

    PubMed

    Borawski, Jacek; Dubowski, Miroslaw; Pawlak, Krystyna; Mysliwiec, Michal

    2007-03-08

    Heparin influences numerous pleiotropic growth factors, including hepatocyte growth factor (HGF), partially by their release from endothelial and extracellular matrix stores. The effects of sulodexide, a heparin-like glycosaminoglycan medication of growing importance in medicine, on HGF liberation are not known. We performed a 2-week open-label sulodexide trial in healthy male volunteers. The drug was initially administered intravenously (i.v.) in a single dose of 1200 Lipoprotein Lipase Releasing Units (LRU), then -- orally for 12 days (500 LRU twice a day), and -- again by i.v. route (1200 LRU) on day 14. Intravenous sulodexide injections were repeatedly found to induce marked and reproducible increases in immunoreactive plasma HGF levels (more than 3500% vs baseline after 10 min, and more than 1200% after 120 min), and remained unchanged when measured 120 min following oral sulodexide administration. The percentage increments in plasma HGF evoked by i.v. sulodexide at both time points and on both days inversely correlated with baseline levels of the growth factor. On day 14, the HGF levels after 120 min and their percentage increase vs baseline were strongly and directly dependent on i.v. sulodexide dose per kg of body weight. This study shows that sulodexide has a novel, remarkable and plausibly biologically important stimulating effect on the release of pleiotropic hepatocyte growth factor in humans.

  2. Release characteristics of encapsulated formulations incorporating plant growth factors.

    PubMed

    Wybraniec, Slawomir; Schwartz, Liliana; Wiesman, Zeev; Markus, Arie; Wolf, David

    2002-05-01

    The release characteristics of encapsulated formulations containing a combination of plant growth factors (PGF)--plant hormones (IBA, paclobutrazol), nutrients (fertilizers, microelements), and fungicide (prochloraz)--were studied. The formulations were prepared by encapsulating the active ingredients in a polyethylene matrix and, in some cases, subsequently coating the product with polyurethane. Dissolution experiments were carried out with both coated and non-coated formulations to determine the sustained release patterns of the active ingredients. The PGF controlled-release systems obtained have been shown to promote development of root systems, vegetative growth, and reproductive development in cuttings, potted plants, or garden plants of various plant species. These beneficial effects are attributable to the lasting and balanced PGF availability provided by these systems.

  3. Gelatin methacrylate microspheres for controlled growth factor release.

    PubMed

    Nguyen, Anh H; McKinney, Jay; Miller, Tobias; Bongiorno, Tom; McDevitt, Todd C

    2015-02-01

    Gelatin has been commonly used as a delivery vehicle for various biomolecules for tissue engineering and regenerative medicine applications due to its simple fabrication methods, inherent electrostatic binding properties, and proteolytic degradability. Compared to traditional chemical cross-linking methods, such as the use of glutaraldehyde (GA), methacrylate modification of gelatin offers an alternative method to better control the extent of hydrogel cross-linking. Here we examined the physical properties and growth factor delivery of gelatin methacrylate (GMA) microparticles (MPs) formulated with a wide range of different cross-linking densities (15-90%). Less methacrylated MPs had decreased elastic moduli and larger mesh sizes compared to GA MPs, with increasing methacrylation correlating to greater moduli and smaller mesh sizes. As expected, an inverse correlation between microparticle cross-linking density and degradation was observed, with the lowest cross-linked GMA MPs degrading at the fastest rate, comparable to GA MPs. Interestingly, GMA MPs at lower cross-linking densities could be loaded with up to a 10-fold higher relative amount of growth factor than conventional GA cross-linked MPs, despite the GA MPs having an order of magnitude greater gelatin content. Moreover, a reduced GMA cross-linking density resulted in more complete release of bone morphogenic protein 4 and basic fibroblast growth factor and accelerated release rate with collagenase treatment. These studies demonstrate that GMA MPs provide a more flexible platform for growth factor delivery by enhancing the relative binding capacity and permitting proteolytic degradation tunability, thereby offering a more potent controlled release system for growth factor delivery.

  4. Gelatin Methacrylate Microspheres for Growth Factor Controlled Release

    PubMed Central

    Nguyen, Anh H.; McKinney, Jay; Miller, Tobias; Bongiorno, Tom; McDevitt, Todd C.

    2014-01-01

    Gelatin has been commonly used as a delivery vehicle for various biomolecules for tissue engineering and regenerative medicine applications due to its simple fabrication methods, inherent electrostatic binding properties, and proteolytic degradability. Compared to traditional chemical cross-linking methods, such as the use of glutaraldehyde (GA), methacrylate modification of gelatin offers an alternative method to better control the extent of hydrogel cross-linking. Here we examined the physical properties and growth factor delivery of gelatin methacrylate (GMA) microparticles formulated with a wide range of different cross-linking densities (15–90%). Less methacrylated MPs had decreased elastic moduli and larger mesh sizes compared to GA MPs, with increasing methacrylation correlating to greater moduli and smaller mesh sizes. As expected, an inverse correlation between microparticle cross-linking density and degradation was observed, with the lowest cross-linked GMA MPs degrading at the fastest rate, comparable to GA MPs. Interestingly, GMA MPs at lower cross-linking densities could be loaded with up to a 10-fold higher relative amount of growth factor over conventional GA cross-linked MPs, despite an order of magnitude greater gelatin content of GA MPs. Moreover, a reduced GMA cross-linking density resulted in more complete release of bone morphogenic protein 4 (BMP4) and basic fibroblast growth factor (bFGF) and accelerated release rate with collagenase treatment. These studies demonstrate that GMA MPs provide a more flexible platform for growth factor delivery by enhancing the relative binding capacity and permitting proteolytic degradation tunability, thereby offering a more potent controlled release system for growth factor delivery. PMID:25463489

  5. Controlled growth factor release from synthetic extracellular matrices

    NASA Astrophysics Data System (ADS)

    Lee, Kuen Yong; Peters, Martin C.; Anderson, Kenneth W.; Mooney, David J.

    2000-12-01

    Polymeric matrices can be used to grow new tissues and organs, and the delivery of growth factors from these matrices is one method to regenerate tissues. A problem with engineering tissues that exist in a mechanically dynamic environment, such as bone, muscle and blood vessels, is that most drug delivery systems have been designed to operate under static conditions. We thought that polymeric matrices, which release growth factors in response to mechanical signals, might provide a new approach to guide tissue formation in mechanically stressed environments. Critical design features for this type of system include the ability to undergo repeated deformation, and a reversible binding of the protein growth factors to polymeric matrices to allow for responses to repeated stimuli. Here we report a model delivery system that can respond to mechanical signalling and upregulate the release of a growth factor to promote blood vessel formation. This approach may find a number of applications, including regeneration and engineering of new tissues and more general drug-delivery applications.

  6. Distribution and release of epidermal growth factor in man.

    PubMed Central

    Konturek, J W; Bielanski, W; Konturek, S J; Bogdal, J; Oleksy, J

    1989-01-01

    Epidermal growth factor (EGF) is localised in man to salivary and Brunner's glands. It is present in large concentrations in saliva and duodenal contents but the mechanisms of its release have been little studied. This study carried out on four groups of healthy subjects was designed to determine the distribution and the release of immunoreactive EGF (IR-EGF) in salivary, gastric, duodenal, and pancreatic secretions. Under basal conditions, the concentrations of IR-EGF in salivary, gastric, duodenal and pancreatic secretions were; 2.7 (0.4), 0.42 (0.12), 21 (5) and 8.5 (1.2) ng/ml, respectively. Chewing of Parafilm* significantly increased salivary but not gastric or duodenal EGF output while atropinisation led to the reduction in basal salivary and duodenal EGF output without affecting the increment in EGF release induced by chewing. Cigarette smoking caused a marked reduction in basal salivary and duodenal EGF output. Infusion of pentagastrin increased salivary and duodenal EGF output and this was blocked by the addition of somatostatin. Injection of secretin lead to an increase in pancreatic output of EGF. We conclude that in man the major sources of EGF are salivary glands, duodenum, and pancreas and that the release of EGF remains under neurohormonal control. PMID:2806986

  7. Polyelectrolyte complexes stabilize and controllably release vascular endothelial growth factor.

    PubMed

    Huang, Min; Vitharana, Samadhi N; Peek, Laura J; Coop, Tina; Berkland, Cory

    2007-05-01

    Angiogenesis has long been a desired therapeutic approach to improve clinical outcomes of conditions typified by ischemia. Vascular endothelial growth factor (VEGF) has demonstrated the ability to generate new blood vessels in vivo, but trials using intravenous delivery have not yet produced clinical success. Localized, sustained delivery of VEGF has been proven necessary to generate blood vessels as demonstrated by implantable, controlled release devices. Ultimately, nanoparticles delivered by intravenous injection may be designed to accumulate in target tissues and sustain the local VEGF concentration; however, injectable nanosuspensions that control the release of stabilized VEGF must first be developed. In this study, we utilize the heparin binding domain of VEGF to bind the polyanion dextran sulfate, resulting in an enhanced thermal stability of VEGF. Coacervation of the VEGF-bound dextran sulfate with selected polycations (chitosan, polyethylenimine, or poly-L-lysine) produced nanoparticles approximately 250 nm in diameter with high VEGF encapsulation efficiency (50-85%). Release of VEGF from these formulations persisted for >10 days and maintained high VEGF activity as determined by ELISA and a mitogenic bioassay. Chitosan-dextran sulfate complexes were preferred because of their biodegradability, desirable particle size ( approximately 250 nm), entrapment efficiency ( approximately 85%), controlled release (near linear for 10 days), and mitogenic activity.

  8. Effect of growth hormone-releasing factor on growth hormone release in children with radiation-induced growth hormone deficiency

    SciTech Connect

    Lustig, R.H.; Schriock, E.A.; Kaplan, S.L.; Grumbach, M.M.

    1985-08-01

    Five male children who received cranial irradiation for extrahypothalamic intracranial neoplasms or leukemia and subsequently developed severe growth hormone (GH) deficiency were challenged with synthetic growth hormone-releasing factor (GRF-44), in an attempt to distinguish hypothalamic from pituitary dysfunction as a cause of their GH deficiency, and to assess the readily releasable GH reserve in the pituitary. In response to a pulse of GRF-44 (5 micrograms/kg intravenously), mean peak GH levels rose to values higher than those evoked by the pharmacologic agents L-dopa or arginine (6.4 +/- 1.3 ng/mL v 1.5 +/- 0.4 ng/mL, P less than .05). The peak GH value occurred at a mean of 26.0 minutes after administration of GRF-44. These responses were similar to those obtained in children with severe GH deficiency due to other etiologies (peak GH 6.3 +/- 1.7 ng/mL, mean 28.0 minutes). In addition, there was a trend toward an inverse relationship between peak GH response to GRF-44 and the postirradiation interval. Prolactin and somatomedin-C levels did not change significantly after the administration of a single dose of GRF-44. The results of this study support the hypothesis that cranial irradiation in children can lead to hypothalamic GRF deficiency secondary to radiation injury of hypothalamic GRF-secreting neurons. This study also lends support to the potential therapeutic usefulness of GRF-44 or an analog for GH deficiency secondary to cranial irradiation.

  9. Nerve growth factor released from a novel PLGA nerve conduit can improve axon growth

    NASA Astrophysics Data System (ADS)

    Lin, Keng-Min; Shea, Jill; Gale, Bruce K.; Sant, Himanshu; Larrabee, Patti; Agarwal, Jay

    2016-04-01

    Nerve injury can occur due to penetrating wounds, compression, traumatic stretch, and cold exposure. Despite prompt repair, outcomes are dismal. In an attempt to help resolve this challenge, in this work, a poly-lactic-co-glycolic acid (PLGA) nerve conduit with associated biodegradable drug reservoir was designed, fabricated, and tested. Unlike current nerve conduits, this device is capable of fitting various clinical scenarios by delivering different drugs without reengineering the whole system. To demonstrate the potential of this device for nerve repair, a series of experiments were performed using nerve growth factor (NGF). First, an NGF dosage curve was developed to determine the minimum NGF concentration for optimal axonal outgrowth on chick dorsal root ganglia (DRG) cells. Next, PLGA devices loaded with NGF were evaluated for sustained drug release and axon growth enhancement with the released drug. A 20 d in vitro release test was conducted and the nerve conduit showed the ability to meet and maintain the minimum NGF requirement determined previously. Bioactivity assays of the released NGF showed that drug released from the device between the 15th and 20th day could still promote axon growth (76.6-95.7 μm) in chick DRG cells, which is in the range of maximum growth. These novel drug delivery conduits show the ability to deliver NGF at a dosage that efficiently promotes ex vivo axon growth and have the potential for in vivo application to help bridge peripheral nerve gaps.

  10. Research Advances in Tissue Engineering Materials for Sustained Release of Growth Factors

    PubMed Central

    Zhao, Hai-yang; Wu, Jiang; Zhu, Jing-jing; Xiao, Ze-cong; He, Chao-chao; Shi, Hong-xue; Li, Xiao-kun; Yang, Shu-lin; Xiao, Jian

    2015-01-01

    Growth factors are a class of cytokines that stimulate cell growth and are widely used in clinical practice, such as wound healing, revascularization, bone repair, and nervous system disease. However, free growth factors have a short half-life and are instable in vivo. Therefore, the search of excellent carriers to enhance sustained release of growth factors in vivo has become an area of intense research interest. The development of controlled-release systems that protect the recombinant growth factors from enzymatic degradation and provide sustained delivery at the injury site during healing should enhance the growth factor's application in tissue regeneration. Thus, this study reviews current research on commonly used carriers for sustained release of growth factors and their sustained release effects for preservation of their bioactivity and their accomplishment in tissue engineering approaches. PMID:26347885

  11. Research Advances in Tissue Engineering Materials for Sustained Release of Growth Factors.

    PubMed

    Zhao, Hai-yang; Wu, Jiang; Zhu, Jing-jing; Xiao, Ze-cong; He, Chao-chao; Shi, Hong-xue; Li, Xiao-kun; Yang, Shu-lin; Xiao, Jian

    2015-01-01

    Growth factors are a class of cytokines that stimulate cell growth and are widely used in clinical practice, such as wound healing, revascularization, bone repair, and nervous system disease. However, free growth factors have a short half-life and are instable in vivo. Therefore, the search of excellent carriers to enhance sustained release of growth factors in vivo has become an area of intense research interest. The development of controlled-release systems that protect the recombinant growth factors from enzymatic degradation and provide sustained delivery at the injury site during healing should enhance the growth factor's application in tissue regeneration. Thus, this study reviews current research on commonly used carriers for sustained release of growth factors and their sustained release effects for preservation of their bioactivity and their accomplishment in tissue engineering approaches.

  12. Growth factor delivery: How surface interactions modulate release in vitro and in vivo

    PubMed Central

    King, William J.; Krebsbach, Paul H.

    2013-01-01

    Biomaterial scaffolds have been extensively used to deliver growth factors to induce new bone formation. The pharmacokinetics of growth factor delivery has been a critical regulator of their clinical success. This review will focus on the surface interactions that control the non-covalent incorporation of growth factors into scaffolds and the mechanisms that control growth factor release from clinically relevant biomaterials. We will focus on the delivery of recombinant human bone morphogenetic protein-2 from materials currently used in the clinical practice, but also suggest how general mechanisms that control growth factor incorporation and release delineated with this growth factor could extend to other systems. A better understanding of the changing mechanisms that control growth factor release during the different stages of preclinical development could instruct the development of future scaffolds for currently untreatable injuries and diseases. PMID:22433783

  13. Release kinetics of platelet-derived and plasma-derived growth factors from autologous plasma rich in growth factors.

    PubMed

    Anitua, Eduardo; Zalduendo, Mari Mar; Alkhraisat, Mohammad Hamdan; Orive, Gorka

    2013-10-01

    Many studies have evaluated the biological effects of platelet rich plasma reporting the final outcomes on cell and tissues. However, few studies have dealt with the kinetics of growth factor delivery by plasma rich in growth factors. Venous blood was obtained from three healthy volunteers and processed with PRGF-Endoret technology to prepare autologous plasma rich in growth factors. The gel-like fibrin scaffolds were then incubated in triplicate, in a cell culture medium to monitor the release of PDGF-AB, VEGF, HGF and IGF-I during 8 days of incubation. A leukocyte-platelet rich plasma was prepared employing the same technology and the concentrations of growth factors and interleukin-1β were determined after 24h of incubation. After each period, the medium was collected, fibrin clot was destroyed and the supernatants were stored at -80°C until analysis. The growth factor delivery is diffusion controlled with a rapid initial release by 30% of the bioactive content after 1h of incubation and a steady state release when almost 70% of the growth factor content has been delivered. Autologous fibrin matrix retained almost 30% of the amount of the growth factors after 8 days of incubation. The addition of leukocytes to the formula of platelet rich plasma did not increase the concentration of the growth factors, while it drastically increased the presence of pro-inflammatory IL-1β. Further studies employing an in vitro inflammatory model would be interesting to study the difference in growth factors and pro-inflammatory cytokines between leukocyte-free and leukocyte-rich platelet rich plasma.

  14. Promoted growth of murine hair follicles through controlled release of vascular endothelial growth factor.

    PubMed

    Ozeki, Makoto; Tabata, Yasuhiko

    2002-06-01

    The objective of this study is to investigate whether or not the controlled release of vascular endothelial growth factor (VEGF) is effective in promoting the hair follicle growth of mice in second anagen of hair cycle. VEGF was incorporated into a biodegradable collagen hydrogel for its controlled release. Following implantation of the collagen hydrogel incorporating 0 or 2 microg of VEGF and injection of 0 or 2 microg of VEGF in the solution form into the back subcutis of mice, the hair follicle growth was evaluated photometrically and histologically in terms of the skin color of reverse side of the implanted or injected site, the skin thickness, and the area occupied by hair follicle tissue. Ten days later, the skin color of mice implanted with the collagen hydrogel incorporating 2 microg of VEGF was significantly darker than that injected with 2 pg of VEGF. The collagen hydrogel incorporating VEGF increased the hair follicle area at the implanted site to a significantly greater extent than other agents while significant angiogenetic effect in the skin tissue was observed. VEGF-free, empty collagen hydrogels did not affect the skin darkness, hair follicle growth, and the angiogenesis. Moreover, the hair shaft length was significantly elongated by the collagen hydrogel incorporating VEGF, in marked contrast to other agents. Immunohistolchemicalstaining with proliferating cell nuclear antigen revealed that the collagen hydrogel incorporating VEGF promoted the proliferation of cells around the hair follicle more frequently than free VEGF. We concluded that the controlled release of VEGF more positively acted on the hair growth cycle of mice for hair growth than the injection of free VEGF.

  15. In situ formation of poly(vinyl alcohol)–heparin hydrogels for mild encapsulation and prolonged release of basic fibroblast growth factor and vascular endothelial growth factor

    PubMed Central

    Roberts, Justine J; Farrugia, Brooke L; Green, Rylie A; Rnjak-Kovacina, Jelena; Martens, Penny J

    2016-01-01

    Heparin-based hydrogels are attractive for controlled growth factor delivery, due to the native ability of heparin to bind and stabilize growth factors. Basic fibroblast growth factor and vascular endothelial growth factor are heparin-binding growth factors that synergistically enhance angiogenesis. Mild, in situ encapsulation of both basic fibroblast growth factor and vascular endothelial growth factor and subsequent bioactive dual release has not been demonstrated from heparin-crosslinked hydrogels, and the combined long-term delivery of both growth factors from biomaterials is still a major challenge. Both basic fibroblast growth factor and vascular endothelial growth factor were encapsulated in poly(vinyl alcohol)-heparin hydrogels and demonstrated controlled release. A model cell line, BaF32, was used to show bioactivity of heparin and basic fibroblast growth factor released from the gels over multiple days. Released basic fibroblast growth factor promoted higher human umbilical vein endothelial cell outgrowth over 24 h and proliferation for 3 days than the poly(vinyl alcohol)-heparin hydrogels alone. The release of vascular endothelial growth factor from poly(vinyl alcohol)-heparin hydrogels promoted human umbilical vein endothelial cell outgrowth but not significant proliferation. Dual-growth factor release of basic fibroblast growth factor and vascular endothelial growth factor from poly(vinyl alcohol)-heparin hydrogels resulted in a synergistic effect with significantly higher human umbilical vein endothelial cell outgrowth compared to basic fibroblast growth factor or vascular endothelial growth factor alone. Poly(vinyl alcohol)-heparin hydrogels allowed bioactive growth factor encapsulation and provided controlled release of multiple growth factors which is beneficial toward tissue regeneration applications. PMID:27895888

  16. Temporally controlled release of multiple growth factors from a self-assembling peptide hydrogel

    NASA Astrophysics Data System (ADS)

    Bruggeman, Kiara F.; Rodriguez, Alexandra L.; Parish, Clare L.; Williams, Richard J.; Nisbet, David R.

    2016-09-01

    Protein growth factors have demonstrated great potential for tissue repair, but their inherent instability and large size prevents meaningful presentation to biologically protected nervous tissue. Here, we create a nanofibrous network from a self-assembling peptide (SAP) hydrogel to carry and stabilize the growth factors. We significantly reduced growth factor degradation to increase their lifespan by over 40 times. To control the temporal release profile we covalently attached polysaccharide chitosan molecules to the growth factor to increase its interactions with the hydrogel nanofibers and achieved a 4 h delay, demonstrating the potential of this method to provide temporally controlled growth factor delivery. We also describe release rate based analysis to examine the growth factor delivery in more detail than standard cumulative release profiles allow and show that the chitosan attachment method provided a more consistent release profile with a 60% reduction in fluctuations. To prove the potential of this system as a complex growth factor delivery platform we demonstrate for the first time temporally distinct release of multiple growth factors from a single tissue specific SAP hydrogel: a significant goal in regenerative medicine.

  17. Controllable mineral coatings on scaffolds as carriers for growth factor release for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Saurez-Gonzalez, Darilis

    The work presented in this document, focused on the development and characterization of mineral coatings on scaffold materials to serve as templates for growth factor binding and release. Mineral coatings were formed using a biomimetic approach that consisted in the incubation of scaffolds in modified simulated body fluids (mSBF). To modulate the properties of the mineral coating, which we hypothesized would dictate growth factor release, we used carbonate (HCO3) concentration in mSBF of 4.2 mM, 25mM, and 100mM. Analysis of the mineral coatings formed using scanning electron microscopy indicated growth of a continuous layer of mineral with different morphologies. X-ray diffraction analysis showed peaks associated with hydroxyapatite. FTIR data confirmed the substitution of HCO3 in the mineral. As the extent of HCO3 substitution increased, the coating exhibited more rapid dissolution kinetics in an environment deficient in calcium and phosphate. The mineral coatings provided an effective mechanism for bioactive growth factor binding and release. Peptide versions of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP2) were bound with efficiencies up to 90% to mineral-coated PCL scaffolds. Recombinant human vascular endothelial growth factor (rhVEGF) also bound to mineral coated scaffolds with lower efficiency (20%) and released with faster release kinetics compared to peptides growth factor. Released rhVEGF induced human umbilical vein endothelial cell (HUVEC) proliferation in vitro and enhanced blood vessel formation in vivo in an intramuscular sheep model. In addition to the use the mineral coatings for single growth factor release, we expanded the concept and bound both an angiogenic (rhVEGF) and osteogenic (mBMP2) growth factor by a simple double dipping process. Sustained release of both growth factors was demonstrated for over 60 days. Released rhVEGF enhanced blood vessel formation in vivo in sheep and its biological activity was

  18. Fluorescence-based retention assays reveals sustained release of vascular endothelial growth factor from bone grafts.

    PubMed

    Kang, Wonmo; Yun, Ye-Rang; Lee, Dong-Sung; Kim, Tae-Hyun; Kim, Joong-Hyun; Kim, Hae-Won; Jang, Jun-Hyeog

    2016-01-01

    The sustained release of growth factors following their implantation in vivo is essential for successful outcomes in bone tissue engineering. In this study, we evaluated the release kinetics and delivery efficacies of vascular endothelial growth factor (VEGF), a potent angiogenic growth factor, incorporated into calcium phosphate bone grafts (BGs). We evaluated the release profile of VEGF from BGs using a novel fluorescence-based retention assay, which revealed that VEGF loaded on BGs can be released in a sustained manner without an initial burst (near zero-order cumulative release) with a controlled release rate of 13.6% per week for up to 7 weeks. In contrast, an ELISA-based release assay showed VEGF to have an early burst-release profile for the first week. However, the biological activity of VEGF released from the BGs was preserved over the 7-week release period, which is consistent with the sustained-release profile observed in the fluorescence-based retention assay. Furthermore, the in vivo bone-forming action of the VEGF-loaded BGs was well demonstrated in a rat subcutaneous model. Taken together, the sustained release of VEGF loaded onto BGs was effective in stimulating proliferation, angiogenesis and osteogenesis, suggesting the ultimate value of VEGF-engineered BGs for bone tissue engineering.

  19. Epidermal growth factor acts as a corticotropin-releasing factor in chronically catheterized fetal lambs.

    PubMed Central

    Polk, D H; Ervin, M G; Padbury, J F; Lam, R W; Reviczky, A L; Fisher, D A

    1987-01-01

    Epidermal growth factor (EGF) has been reported to stimulate adrenocorticotropin hormone (ACTH), growth hormone and prolactin secretion from pituitary tissue in vitro, and in large doses evokes ACTH secretion in adult sheep in vivo. In order to assess a possible role for EGF in the pituitary hyperfunction characteristic of the in utero fetus, we measured changes in plasma immunoreactive ACTH concentrations after acute administration of saline, purified mouse EGF or synthetic ovine corticotropin releasing factor (CRF) to chronically catheterized fetal sheep. Both CRF and EGF were associated with increases in plasma immunoreactive ACTH concentrations. Peak values 60 min after 10-micrograms injections of either EGF or CRF increased from baseline ACTH values of 61 +/- 11 pg/ml to 191 +/- 37 and 178 +/- 25 pg/ml, respectively. Dose-response studies indicate that at low doses (less than 20 micrograms) EGF is as potent a stimulus for ACTH release as CRF. EGF infusion was not associated with detectable changes in circulating CRF, catecholamines, arginine vasopressin levels, or plasma growth hormone concentrations. We speculate that EGF may be important in the regulation of pituitary function in the developing mammalian fetus. PMID:3029180

  20. Tumor necrosis factor-mediated release of platelet-derived growth factor from cultured endothelial cells

    PubMed Central

    1987-01-01

    Platelet-derived growth factor (PDGF) is a 30,000-Mr glycoprotein that is chemotactic and mitogenic for vascular smooth muscle cells (SMC). It is also a potent vasoconstrictor. In the present study, we found that the macrophage-derived polypeptide, tumor necrosis factor (TNF), releases a factor from human umbilical vein endothelial cells (EC) that is mitogenic for SMC. Postculture medium from TNF-stimulated EC induced a 90% increase in mitogenesis is compared with controls. This effect was half-maximal at a TNF dose of 114 pM, reflected a 2.5-fold increase in PDGF-specific mRNA synthesis, and peaked at 15 h of TNF stimulation. Mitogenic activity was completely abrogated by preincubation of postculture medium with antibody to platelet PDGF. Stimulation of EC with IL-1 (60-240 pM) led to the release of similar mitogenic activity. Thus, in addition to its effects on the hemostatic and adhesive properties of EC, TNF also promotes release of PDGF, which may serve to modulate proliferation of vascular SMC during wound healing, inflammation, and atherogenesis. PMID:3598461

  1. Effect of Cellulose Acetate Beads on the Release of Transforming Growth Factor-β.

    PubMed

    Nishise, Shoichi; Abe, Yasuhiko; Nomura, Eiki; Sato, Takeshi; Sasaki, Yu; Iwano, Daisuke; Yagi, Makoto; Sakuta, Kazuhiro; Shibuya, Rika; Mizumoto, Naoko; Kanno, Nana; Ueno, Yoshiyuki

    2015-08-01

    Transforming growth factor-β (TGF-β) is released by activated platelets and induces the differentiation of T-helper 17 from naïve T cells. Contact between blood and cellulose acetate (CA) beads induces cytokine release, although their inflammatory effects on TGF-β release are unclear. We aimed to clarify the effect of CA beads on the release of TGF-β in vitro. We incubated peripheral blood with and without CA beads and measured platelets and TGF-β. Compared with blood samples incubated without beads, the platelet count and amount of TGF-β significantly decreased in blood samples incubated with CA beads. In conclusion, CA beads inhibited the release of TGF-β from adsorbed platelets. The biological effects of this reduction of TGF-β release during platelet adsorption to CA beads need further clarification.

  2. Growth hormone secretion from chicken adenohypophyseal cells in primary culture: effects of human pancreatic growth hormone-releasing factor, thyrotropin-releasing hormone, and somatostatin on growth hormone release.

    PubMed

    Perez, F M; Malamed, S; Scanes, C G

    1987-03-01

    A primary culture of chicken adenohypophyseal cells has been developed to study the regulation of growth hormone (GH) secretion. Following collagenase dispersion, cells were exposed for 2 hr to vehicle (control) or test agents. Human pancreatic (tumor) growth hormone-releasing factor (hpGRF) and rat hypothalamic growth hormone-releasing factor stimulated GH release to similar levels. GH release was increased by the presence of dibutyryl cyclic AMP. Thyrotropin-releasing hormone (TRH) alone did not influence GH release; however, TRH plus hpGRF together exerted a synergistic (greater than additive) effect, increasing GH release by 100 to 300% over the sum of the values for each secretagogue acting alone. These relationships between TRH and hpGRF were further examined in cultured cells exposed to secretagogues for two consecutive 2-hr incubations. TRH pretreatment enhanced subsequent hpGRF-stimulated GH release by about 80% over that obtained if no secretagogue was present during the first incubation. In other experiments, somatostatin (SRIF) alone did not alter GH secretion. However, SRIF reduced hpGRF-stimulated GH release to levels found in controls. Furthermore, GH release stimulated by the presence of both TRH and hpGRF was lowered to control values by SRIF. The results of these studies demonstrate that a primary culture of chicken adenohypophyseal cells is a useful model for the study of GH secretion. Indeed, these results suggest that TRH and hpGRF regulate GH secretion by mechanisms which are not identical.

  3. Mineral coatings modulate β-TCP stability and enable growth factor binding and release.

    PubMed

    Suárez-González, Darilis; Lee, Jae Sung; Lan Levengood, Sheeny K; Vanderby, Ray; Murphy, William L

    2012-03-01

    β-Tricalcium phosphate (β-TCP) is an attractive ceramic for bone tissue repair because of its similar composition to bone mineral and its osteoconductivity. However, compared with other ceramics β-TCP has a rapid and uncontrolled rate of degradation. In the current study β-TCP granules were mineral coated with the aim of influencing the dissolution rate of β-TCP, and also to use the coating as a carrier for controlled release of the growth factors recombinant human vascular endothelial growth factor (rhVEGF), modular VEGF peptide (mVEGF), and modular bone morphogenetic protein 2 peptide (mBMP2). The biomineral coatings were formed by heterogeneous nucleation in aqueous solution using simulated body fluid solutions with varying concentrations of bicarbonate (HCO(3)). Our results demonstrate that we could coat β-TCP granules with mineral layers possessing different dissolution properties. The presence of a biomineral coating delays the dissolution rate of the β-TCP granules. As the carbonate (CO(3)(2-)) content in the coating was increased the dissolution rate of the coated β-TCP also increased, but remained slower than the dissolution of uncoated β-TCP. In addition, we showed sustained release of multiple growth factors, with release kinetics that were controllable by varying the identity of the growth factor or the CO(3)(2-) content in the mineral coating. Released rhVEGF induced human umbilical vein endothelial cell (HUVEC) proliferation, and mVEGF enhanced migration of mouse embryonic endothelial cells in a scratch wound healing assay, indicating that each released growth factor was biologically active.

  4. Gelatin-based hydrogel for vascular endothelial growth factor release in peripheral nerve tissue engineering.

    PubMed

    Gnavi, S; di Blasio, L; Tonda-Turo, C; Mancardi, A; Primo, L; Ciardelli, G; Gambarotta, G; Geuna, S; Perroteau, I

    2017-02-01

    Hydrogels are promising materials in regenerative medicine applications, due to their hydrophilicity, biocompatibility and capacity to release drugs and growth factors in a controlled manner. In this study, biocompatible and biodegradable hydrogels based on blends of natural polymers were used in in vitro and ex vivo experiments as a tool for VEGF-controlled release to accelerate the nerve regeneration process. Among different candidates, the angiogenic factor VEGF was selected, since angiogenesis has been long recognized as an important and necessary step during tissue repair. Recent studies have pointed out that VEGF has a beneficial effect on motor neuron survival and Schwann cell vitality and proliferation. Moreover, VEGF administration can sustain and enhance the growth of regenerating peripheral nerve fibres. The hydrogel preparation process was optimized to allow functional incorporation of VEGF, while preventing its degradation and denaturation. VEGF release was quantified through ELISA assay, whereas released VEGF bioactivity was validated in human umbilical vein endothelial cells (HUVECs) and in a Schwann cell line (RT4-D6P2T) by assessing VEGFR-2 and downstream effectors Akt and Erk1/2 phosphorylation. Moreover, dorsal root ganglia explants cultured on VEGF-releasing hydrogels displayed increased neurite outgrowth, providing confirmation that released VEGF maintained its effect, as also confirmed in a tubulogenesis assay. In conclusion, a gelatin-based hydrogel system for bioactive VEGF delivery was developed and characterized for its applicability in neural tissue engineering. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Silk fibroin matrices for the controlled release of nerve growth factor (NGF).

    PubMed

    Uebersax, Lorenz; Mattotti, Marta; Papaloïzos, Michaël; Merkle, Hans P; Gander, Bruno; Meinel, Lorenz

    2007-10-01

    Nerve conduits (NC) for peripheral nerve repair should guide the sprouting axons and physically protect the axonal cone from any damage. The NC should also degrade after completion of its function to obviate the need of subsequent explanation and should optionally be suitable for controlled drug release of embedded growth factors to enhance nerve regeneration. Silk fibroin (SF) is a biocompatible and slowly biodegradable biomaterial with excellent mechanical properties that could meet the above stated requirements. SF material (films) supported the adherence and metabolic activity of PC12 cells, and, in combination with nerve growth factor (NGF), supported neurite outgrowth during PC12 cell differentiation. NGF-loaded SF-NC were prepared from aqueous solutions of NGF and SF (20%, w/w), which were air-dried or freeze-dried (freezing at -20 or -196 degrees C) in suitable molds. NGF release from the three differently prepared SF-NC was prolonged over at least 3 weeks, but the total amount released depended on the drying procedure of the NC. The potency of released NGF was retained within all formulations. Control experiments with differently dried NGF-lactose solutions did not evidence marked protein aggregation (SEC, HPLC), loss of ELISA-reactivity or PC12 cell bioactivity. This study encourages the further exploitation of SF-NC for growth factor delivery and evaluation in peripheral nerve repair.

  6. Study of the biological effectiveness of a nanosilver-epidermal growth factor sustained-release carrier.

    PubMed

    Zhou, Jian-DA; Wang, Shao-Hua; Liu, Rui; Zhou, Chun-Jiao; Cao, Ke; Liu, Jin-Yan; Chen, Yao; Chen, Feng-Hua

    2013-04-01

    The aim of the present study was to elucidate the biological effectiveness and character of a nanosilver-epidermal growth factor (EGF) sustained-release carrier. This was synthesized using the self-assembly method and then characterized by transmission electron microscopy and UV spectrophotometry. The biological activity of the sustained release carrier was determined through cytological, bacteriological and wound-healing experiments. The results showed that the nanosilver-EGF sustained-release carrier was well dispersed with uniform particle size and that it had good antibacterial properties similar to those of nanosilver. The nanosilver-EGF sustained-release carrier is superior to EGFs in effectively promoting cell division and proliferation. The results of the wound-healing experiments provide evidence of its curative effects.

  7. Growth factor and co-receptor release by structural regulation of substrate metalloprotease accessibility

    PubMed Central

    Parra, Liseth M.; Hartmann, Monika; Schubach, Salome; Ma, Junzhi; Herrlich, Peter; Herrlich, Andreas

    2016-01-01

    Release of cytokines, growth factors and other life-essential molecules from precursors by a-disintegrin-and-metalloproteases (ADAMs) is regulated with high substrate-specificity. We hypothesized that this is achieved by cleavage-regulatory intracellular-domain (ICD)-modifications of the precursors. We show here that cleavage-stimuli-induced specific ICD-modifications cause structural substrate changes that enhance ectodomain sensitivity of neuregulin-1 (NRG1; epidermal-growth-factor) or CD44 (receptor-tyrosine-kinase (RTK) co-receptor) to chymotrypsin/trypsin or soluble ADAM. This inside-out signal transfer required substrate homodimerization and was prevented by cleavage-inhibitory ICD-mutations. In chimeras, regulation could be conferred to a foreign ectodomain, suggesting a common higher-order structure. We predict that substrate-specific protease-accessibility-regulation controls release of numerous ADAM substrates. PMID:27876763

  8. Elongation factor 1-alpha is released into the culture medium during growth of Giardia intestinalis trophozoites.

    PubMed

    Skarin, Hanna; Ringqvist, Emma; Hellman, Ulf; Svärd, Staffan G

    2011-04-01

    The molecular pathogenesis of the intestinal parasite Giardia intestinalis is still not fully understood but excretory-secretory products have been suggested to be important during host-parasite interactions. Here we used SDS-PAGE gels and MALDI-TOF analysis to identify proteins released by Giardia trophozoites during in vitro growth. Serum proteins (mainly bovine serum albumin) in the growth medium, bind to the parasite surface and they are continuously released, which interfere with parasite secretome characterization. However, we identified two released Giardia proteins: elongation factor-1 alpha (EF-1α) and a 58 kDa protein, identified as arginine deiminase (ADI). This is the first description of EF-1α as a released/secreted Giardia protein, whereas ADI has been identified in an earlier secretome study. Two genes encoding EF-1α were detected in the Giardia WB genome 35 kbp apart with almost identical coding sequences but with different promoter and 3' regions. Promoter luciferase-fusions showed that both genes are transcribed in trophozoites. The EF-1α protein localizes to the nuclear region in trophozoites but it relocalizes to the cytoplasm during host-cell interaction. Recombinant EF-1α is recognized by serum from giardiasis patients. Our results suggest that released EF-1α protein can be important during Giardia infections.

  9. Epidermal growth factor released in human dental pulp following orthodontic force.

    PubMed

    Derringer, Kathryn; Linden, Roger

    2007-02-01

    This study investigated the role of human epidermal growth factor (EGF) in the angiogenic response of the dental pulp to orthodontic force. The release of angiogenic growth factor EGF in human dental pulp following orthodontic force application was examined using neutralizing antibody anti-human (anti-h) EGF to block its effects. The dental pulps from 10 premolar teeth from 10 patients (equal numbers of males and females aged 11-14 years), treated with a straightwire fixed appliance for 2 weeks and extracted for orthodontic reasons, were divided vertically, and sections from each half-pulp were individually co-cultured with a section of rat aorta in collagen surrounded by growth media. Anti-h EGF was added to the media of the co-cultures from one-half of each pulp from each tooth from each patient; the remaining co-cultures from the other half of each pulp without anti-h EGF were used as the controls. Cultures were examined daily by light microscopy for angiogenic growth and number of microvessels. The addition of anti-h EGF to the growth media in the co-cultures resulted in a significant reduction (P < 0.05, Wilcoxon signed rank test) in pulpal and rat aorta microvessel numbers, compared with the control co-cultures. The results indicate that EGF released following orthodontic force application plays a part in the angiogenic response of the pulp.

  10. Dual growth factor releasing multi-functional nanofibers for wound healing.

    PubMed

    Xie, Zhiwei; Paras, Christian B; Weng, Hong; Punnakitikashem, Primana; Su, Lee-Chun; Vu, Khanh; Tang, Liping; Yang, Jian; Nguyen, Kytai T

    2013-12-01

    The objective of this research is to develop a dual growth factor-releasing nanoparticle-in-nanofiber system for wound healing applications. In order to mimic and promote the natural healing procedure, chitosan and poly(ethylene oxide) were electrospun into nanofibrous meshes as mimics of extracellular matrix. Vascular endothelial growth factor (VEGF) was loaded within nanofibers to promote angiogenesis in the short term. In addition, platelet-derived growth factor-BB (PDGF-BB) encapsulated poly(lactic-co-glycolic acid) nanoparticles were embedded inside nanofibers to generate a sustained release of PDGF-BB for accelerated tissue regeneration and remodeling. In vitro studies revealed that our nanofibrous composites delivered VEGF quickly and PDGF-BB in a relayed manner, supported fibroblast growth and exhibited anti-bacterial activities. A preliminary in vivo study performed on normal full thickness rat skin wound models demonstrated that nanofiber/nanoparticle scaffolds significantly accelerated the wound healing process by promoting angiogenesis, increasing re-epithelialization and controlling granulation tissue formation. For later stages of healing, evidence also showed quicker collagen deposition and earlier remodeling of the injured site to achieve a faster full regeneration of skin compared to the commercial Hydrofera Blue® wound dressing. These results suggest that our nanoparticle-in-nanofiber system could provide a promising treatment for normal and chronic wound healing.

  11. Platelets modulate gastric ulcer healing: role of endostatin and vascular endothelial growth factor release.

    PubMed

    Ma, L; Elliott, S N; Cirino, G; Buret, A; Ignarro, L J; Wallace, J L

    2001-05-22

    Bleeding and delayed healing of ulcers are well recognized clinical problems associated with the use of aspirin and other nonsteroidal antiinflammatory drugs, which have been attributed to their antiaggregatory effects on platelets. We hypothesized that antiplatelet drugs might interfere with gastric ulcer healing by suppressing the release of growth factors, such as vascular endothelial growth factor (VEGF), from platelets. Gastric ulcers were induced in rats by serosal application of acetic acid. Daily oral treatment with vehicle, aspirin, or ticlopidine (an ADP receptor antagonist) was started 3 days later and continued for 1 week. Ulcer induction resulted in a significant increase in serum levels of VEGF and a significant decrease in serum levels of endostatin (an antiangiogenic factor). Although both aspirin and ticlopidine markedly suppressed platelet aggregation, only ticlopidine impaired gastric ulcer healing and angiogenesis as well as reversing the ulcer-associated changes in serum levels of VEGF and endostatin. The effects of ticlopidine on ulcer healing and angiogenesis were mimicked by immunodepletion of circulating platelets, and ticlopidine did not influence ulcer healing when given to thrombocytopenic rats. Incubation of human umbilical vein endothelial cells with serum from ticlopidine-treated rats significantly reduced proliferation and increased apoptosis, effects reversed by an antibody directed against endostatin. Ticlopidine treatment resulted in increased platelet endostatin content and release. These results demonstrate a previously unrecognized contribution of platelets to the regulation of gastric ulcer healing. Such effects likely are mediated through the release from platelets of endostatin and possibly VEGF. As shown with ticlopidine, drugs that influence gastric ulcer healing may do so in part through altering the ability of platelets to release growth factors.

  12. In vitro characterization of hepatocyte growth factor release from PHBV/PLGA microsphere scaffold.

    PubMed

    Zhu, Xin Hao; Wang, Chi-Hwa; Tong, Yen Wah

    2009-05-01

    Polymer scaffolds which can support cells to grow as well as deliver growth factors to the cells simultaneously have great potential for the successful regeneration of failed tissues. As popularly used vehicles to deliver anti-cancer drugs and growth factors, microspheres also show many advantages as substrates to guide the growth of cells. Therefore, we aimed to examine the feasibility of using microspheres as ideal scaffolds for liver tissue engineering. To determine the capabilities of previously used microsphere scaffold to deliver growth factors simultaneously, this work investigated a long-term (about three months) release of bovine serum albumin (BSA) from microsphere scaffolds fabricated by using two different polymers, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV, 8% PHV), poly(lactide-co-glycolide) acid (PLGA, 5050) and a blend of PLGA and PHBV. BSA served as a model for hepatocyte growth factor (HGF) since both proteins have similar molecular weights and hydrophilicity. Furthermore, HGF was encapsulated into the PLGA/PHBV composite microsphere with a core-shell structure, and sustained delivery of HGF with maintained bioactivity was achieved for at least 40 days. The moderate degradation rate (about 55% loss of the initial mass) and well-preserved structure after three months of incubation indicated that the PLGA/PHBV composite microspheres would therefore be more suitable than the pure PHBV or PLGA microspheres as a scaffold for engineering liver tissue.

  13. A novel collagen/platelet-rich plasma (COL/PRP) scaffold: preparation and growth factor release analysis.

    PubMed

    Zhang, Xiujie; Wang, Jingwei; Ren, Mingguang; Li, Lifeng; Wang, Qingwen; Hou, Xiaohua

    2016-06-01

    Platelet-rich plasma (PRP) has been widely used in clinical practice for more than 20 years because it causes the release of many growth factors. However, the burst release pattern and short release period of PRP have become obstacles to its application. An optimal controllable release system is an urgent need for researchers. This study investigated whether collagen/PRP (COL/PRP) scaffolds can serve as a vehicle for the controllable release of growth factors. We fabricated a novel scaffold that integrates PRP activated by thrombin or collagen into type I collagen. The mechanical properties, cytotoxicity, and transforming growth factor β1 (TGF-β1), platelet derived growth factor (PDGF), fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) content were evaluated. Our results demonstrate that the COL/PRP scaffolds were not cytotoxic to L-929 fibroblasts. The PDGF and FGF content in the thrombin group was at a higher level and lasted for a long period of time. Collagen and thrombin played the same role in the release of TGF-β1 and VEGF. These data suggest that the novel COL/PRP scaffolds provide a carrier for the controllable release of growth factors and may be used in tissue- regenerative therapies.

  14. Injectable gelatin derivative hydrogels with sustained vascular endothelial growth factor release for induced angiogenesis.

    PubMed

    Li, Zhe; Qu, Tiejun; Ding, Chen; Ma, Chi; Sun, Hongchen; Li, Shirong; Liu, Xiaohua

    2015-02-01

    Injectable biomaterials are attractive for soft tissue regeneration because they are handled in a minimally invasive manner and can easily adapt to complex defects. However, inadequate vascularization of the injectable constructs has long been a barrier, leading to necrosis or volume reduction after implantation. In this work, we developed a three-step process to synthesize injectable gelatin-derived hydrogels that are capable of controlling growth factor delivery to induce angiogenesis. In our approach, tyramine was first introduced into gelatin chains to provide enzymatic crosslinking points for gel formation after injection. Next, heparin, a polysaccharide with binding domains to many growth factors, was covalently linked to the tyramine-modified gelatin. Finally, vascular endothelial growth factor (VEGF) was incorporated into the gelatin derivative by binding with the heparin in the gelatin derivative, and an injectable gel with controlled VEGF release was formed by an enzymatic catalytic reaction with hydrogen peroxide (H2O2) and horseradish peroxidase (HRP). The gelation time, mechanical properties and degradation of the gel was readily tailored by the gelatin concentration and the ratio of H2O2/HRP. Binding VEGF to heparin stabilizes this growth factor, protects it from denaturation and proteolytic degradation and subsequently prolongs the sustained release. An in vitro release study and bioactivity assay indicated that the VEGF was released in a sustained manner with high bioactivity for over 3 weeks. Furthermore, a chicken chorioallantoic membrane (CAM) assay and animal experiments were performed to evaluate in vivo bioactivity of the VEGF released from the hydrogels. After 5 days of incubation on CAM, the number of blood vessels surrounding the heparin-modified hydrogels was increased by 2.4-fold compared with that of the control group. Deeper and denser cell infiltration and angiogenesis in the heparin-modified gelatin/VEGF gels were observed compared to

  15. Dual-stage growth factor release within 3D protein-engineered hydrogel niches promotes adipogenesis

    PubMed Central

    Greenwood-Goodwin, Midori; Teasley, Eric S.; Heilshorn, Sarah C.

    2014-01-01

    Engineered biomimetic microenvironments from hydrogels are an emerging strategy to achieve lineage-specific differentiation in vitro. In addition to recapitulating critical matrix cues found in the native three-dimensional (3D) niche, the hydrogel can also be designed to deliver soluble factors that are present within the native inductive microenvironment. We demonstrate a versatile materials approach for the dual-stage delivery of multiple soluble factors within a 3D hydrogel to induce adipogenesis. We use a Mixing-Induced Two-Component Hydrogel (MITCH) embedded with alginate microgels to deliver two pro-adipogenic soluble factors, fibroblast growth factor 1 (FGF-1) and bone morphogenetic protein 4 (BMP-4) with two distinct delivery profiles. We show that dual-stage delivery of FGF-1 and BMP-4 to human adipose-derived stromal cells (hADSCs) significantly increases lipid accumulation compared with the simultaneous delivery of both growth factors together. Furthermore, dual-stage growth factor delivery within a 3D hydrogel resulted in substantially more lipid accumulation compared to identical delivery profiles in 2D cultures. Gene expression analysis shows upregulation of key adipogenic markers indicative of brown-like adipocytes. These data suggest that dual-stage release of FGF-1 and BMP-4 within 3D microenvironments can promote the in vitro development of mature adipocytes. PMID:25309741

  16. The Effect of Vitamin D Treatment On Nerve Growth Factor (NGF) Release From Hippocampal Neurons

    PubMed Central

    GEZEN-AK, Duygu; DURSUN, Erdinç; YILMAZER, Selma

    2014-01-01

    Introduction Vitamin D, the main function of which is thought to be the maintenance of calcium and phosphate homeostasis and bone structure, has been shown in recent studies to have important roles in brain development as well. A certain vitamin D receptor (VDR) gene haplotype was reported, for the first time by our group, to increase the risk of developing Alzheimer’s disease. Our studies also showed that vitamin D prevents beta amyloid-induced calcium elevation and toxicity that target nerve growth factor (NGF) release in cortical neurons; beta amyloid suppresses VDR expression and the disruption of vitamin D-VDR pathway mimics beta amyloid-induced neurodegeneration. In this study, our aim was to investigate the effects of vitamin D on the NGF release from hippocampal neurons. Method Primary hippocampal neuron cultures that were prepared from 18-day-old Sprague-Dawley rat embryos were treated with vitamin D for 48 hours. The alteration in the NGF release was determined with ELISA. Cytotoxicity tests were also performed for all groups. Results The NGF release in vitamin D-treated group was significantly higher than in untreated control group. The protective effect of vitamin D against cytotoxicity was also observed. Conclusion Our results indicated that vitamin D regulates the release of NGF, a very important molecule for neuronal survival of hippocampal neurons as well as cortical neurons.

  17. Fluid flow releases fibroblast growth factor-2 from human aortic smooth muscle cells

    NASA Technical Reports Server (NTRS)

    Rhoads, D. N.; Eskin, S. G.; McIntire, L. V.

    2000-01-01

    This study tested the hypothesis that fluid shear stress regulates the release of fibroblast growth factor (FGF)-2 from human aortic smooth muscle cells. FGF-2 is a potent mitogen that is involved in the response to vascular injury and is expressed in a wide variety of cell types. FGF-2 is found in the cytoplasm of cells and outside cells, where it associates with extracellular proteoglycans. To test the hypothesis that shear stress regulates FGF-2 release, cells were exposed to flow, and FGF-2 amounts were measured from the conditioned medium, pericellular fraction (extracted by heparin treatment), and cell lysate. Results from the present study show that after 15 minutes of shear stress at 25 dyne/cm(2) in a parallel-plate flow system, a small but significant fraction (17%) of the total FGF-2 was released from human aortic smooth muscle cells. FGF-2 levels in the circulating medium increased 10-fold over medium from static controls (P<0.01). A 50% increase in FGF-2 content versus control (P<0.01) was found in the pericellular fraction (extracted by heparin treatment). Furthermore, a significant decrease in FGF-2 was detected in the cell lysate, indicating that FGF-2 was released from inside the cell. Cell permeability studies with fluorescent dextran were performed to examine whether transient membrane disruption caused FGF-2 release. Flow cytometry detected a 50% increase in mean fluorescence of cells exposed to 25 dyne/cm(2) versus control cells. This indicates that the observed FGF-2 release from human aortic smooth muscle cells is likely due to transient membrane disruption on initiation of flow.

  18. Calcium-Alginate Hydrogel-Encapsulated Fibroblasts Provide Sustained Release of Vascular Endothelial Growth Factor

    PubMed Central

    Hunt, Nicola C.; Shelton, Richard M.; Henderson, Deborah J.

    2013-01-01

    Vascularization of engineered or damaged tissues is essential to maintain cell viability and proper tissue function. Revascularization of the left ventricle (LV) of the heart after myocardial infarction is particularly important, since hypoxia can give rise to chronic heart failure due to inappropriate remodeling of the LV after death of cardiomyocytes (CMs). Fibroblasts can express vascular endothelial growth factor (VEGF), which plays a major role in angiogenesis and also acts as a chemoattractant and survival factor for CMs and cardiac progenitors. In this in vitro model study, mouse NIH 3T3 fibroblasts encapsulated in 2% w/v Ca-alginate were shown to remain viable for 150 days. Semiquantitative reverse transcription–polymerase chain reaction and immunohistochemistry demonstrated that over 21 days of encapsulation, fibroblasts continued to express VEGF, while enzyme-linked immunosorbent assay showed that there was sustained release of VEGF from the Ca-alginate during this period. The scaffold degraded gradually over the 21 days, without reduction in volume. Cells released from the Ca-alginate at 7 and 21 days as a result of scaffold degradation were shown to retain viability, to adhere to fibronectin in a normal manner, and continue to express VEGF, demonstrating their potential to further contribute to maintenance of cardiac function after scaffold degradation. This model in vitro study therefore demonstrates that fibroblasts encapsulated in Ca-alginate provide sustained release of VEGF. PMID:23082964

  19. Purification of a high-molecular-weight somatoliberin (growth-hormone-releasing factor) from pig hypothalami.

    PubMed Central

    Sykes, J E; Lowry, P J

    1983-01-01

    Preliminary observations [Sykes & Lowry (1980) J. Endocrinol. 85, 42P-43P] had suggested that the major hypothalamic somatoliberin (growth-hormone-releasing factor) was a larger peptide than the other characterized hypothalamic factors, with an elution position on Sephadex G-50 between those of neurophysin and corticotropin. The present paper reports the isolation and preliminary characterization of pig hypothalamic somatoliberin. Acid extracts of pig stalk median eminence were purified by gel filtration and preparative and analytical high-pressure liquid chromatography to yield a preparation that was specific in the release of somatotropin (growth hormone) in vitro, giving a steep dose--response curve at doses in the range 0.20-3.0 ng. Amino acid analysis revealed a non-cysteine-containing peptide with a high number of glutamate (or glutamine) and aspartate (or asparagine) residues. The peptide had about 56-57 amino acid residues and an apparent molecular weight of 6400, in keeping with its elution position on a column of Sephadex G-50. PMID:6409074

  20. In Situ Loading of Basic Fibroblast Growth Factor Within Porous Silica Nanoparticles for a Prolonged Release

    NASA Astrophysics Data System (ADS)

    Zhang, Jin; Postovit, Lynne-Marie; Wang, Dashan; Gardiner, Richard B.; Harris, Richard; Abdul, Mumin Md; Thomas, Anu Alice

    2009-11-01

    Basic fibroblast growth factor (bFGF), a protein, plays a key role in wound healing and blood vessel regeneration. However, bFGF is easily degraded in biologic systems. Mesoporous silica nanoparticles (MSNs) with well-tailored porous structure have been used for hosting guest molecules for drug delivery. Here, we report an in situ route to load bFGF in MSNs for a prolonged release. The average diameter ( d) of bFGF-loaded MSNs is 57 ± 8 nm produced by a water-in-oil microemulsion method. The in vitro releasing profile of bFGF from MSNs in phosphate buffer saline has been monitored for 20 days through a colorimetric enzyme linked immunosorbent assay. The loading efficiency of bFGF in MSNs is estimated at 72.5 ± 3%. In addition, the cytotoxicity test indicates that the MSNs are not toxic, even at a concentration of 50 μg/mL. It is expected that the in situ loading method makes the MSNs a new delivery system to deliver protein drugs, e.g. growth factors, to help blood vessel regeneration and potentiate greater angiogenesis.

  1. Sustaining neovascularization of a scaffold through staged release of vascular endothelial growth factor-A and platelet-derived growth factor-BB.

    PubMed

    Davies, Neil H; Schmidt, Christian; Bezuidenhout, Deon; Zilla, Peter

    2012-01-01

    Tissue regeneration into a three-dimensional scaffold requires the stimulation of blood vessel ingrowth. We have employed a freely interconnecting porous scaffold developed by us to determine the utility of a covalently bound heparin surface coating for the delivery of vascular endothelial growth factor (VEGF) and platelet-derived growth factor BB (PDGF-BB) in vivo. The heparin surface was shown to release VEGF far more rapidly than PDGF-BB in vitro (VEGF: 75 ng/h for 24 h; PDGF-BB: 86 pg/h for >7 days). In rat subcutaneous implants, at 10 days the heparin surface alone increased vessel ingrowth substantially (p<0.05 vs. unmodified scaffold), release of VEGF resulted in a further increase (p<0.05 vs. heparinized scaffold), whereas PDGF-BB had no additional effect. The increase induced by the combination of growth factors was similar to VEGF alone. After 2 months, PDGF-BB, but not VEGF delivery, resulted in a substantial increase in vascularization above that induced by heparin (p<0.05). At the longer time point the combination of growth factors was similar to PDGF-BB. However, only the combination of growth factors significantly elevated the number of ingrowing arterioles (p<0.05 vs. heparinized scaffold). Thus, the covalent modification of a porous scaffold with heparin allows for the differential release of VEGF and PDGF-BB that results in both a rapid and sustained increase in scaffold vascularization.

  2. Effect of trehalose coating on basic fibroblast growth factor release from tailor-made bone implants.

    PubMed

    Choi, Sungjin; Lee, Jongil; Igawa, Kazuyo; Suzuki, Shigeki; Mochizuki, Manabu; Nishimura, Ryohei; Chung, Ung-il; Sasaki, Nobuo

    2011-12-01

    Artificial bone implants are often incorporated with osteoinductive factors to facilitate early bone regeneration. Calcium phosphate, the main component in artificial bone implants, strongly binds these factors, and in a few cases, the incorporated proteins are not released from the implant under conditions of physiological pH, thereby leading to reduction in their osteoinductivity. In this study, we coated tailor-made bone implants with trehalose to facilitate the release of basic fibroblast growth factor (bFGF). In an in vitro study, mouse osteoblastic cells were separately cultured for 48 hr in a medium with a untreated implant (T-), trehalose-coated implant (T+), bFGF-incorporated implant (FT-), and bFGF-incorporated implant with trehalose coating (FT+). In the FT+ group, cell viability was significantly higher than that in the other groups (P<0.05). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that trehalose effectively covered the surface of the artificial bone implant without affecting the crystallinity or the mechanical strength of the artificial bone implant. These results suggest that coating artificial bone implants with trehalose could limit the binding of bFGF to calcium phosphate.

  3. Rapid release of growth factors regenerates force output in volumetric muscle loss injuries

    PubMed Central

    Grasman, Jonathan M.; Do, Duc M.; Page, Raymond L.; Pins, George D.

    2015-01-01

    A significant challenge in the design and development of biomaterial scaffolds is to incorporate mechanical and biochemical cues to direct organized tissue growth. In this study, we investigated the effect of hepatocyte growth factor (HGF) loaded, crosslinked fibrin (EDCn-HGF) microthread scaffolds on skeletal muscle regeneration in a mouse model of volumetric muscle loss (VML). The rapid, sustained release of HGF significantly enhanced the force production of muscle tissue 60 days after injury, recovering more than 200% of the force output relative to measurements recorded immediately after injury. HGF delivery increased the number of differentiating myoblasts 14 days after injury, and supported an enhanced angiogenic response. The architectural morphology of microthread scaffolds supported the ingrowth of nascent myofibers into the wound site, in contrast to fibrin gel implants which did not support functional regeneration. Together, these data suggest that EDCn-HGF microthreads recapitulate several of the regenerative cues lost in VML injuries, promote remodeling of functional muscle tissue, and enhance the functional regeneration of skeletal muscle. Further, by strategically incorporating specific biochemical factors and precisely tuning the structural and mechanical properties of fibrin microthreads, we have developed a powerful platform technology that may enhance regeneration in other axially aligned tissues. PMID:26344363

  4. Basic fibroblast growth factor priming increases the responsiveness of immortalized hypothalamic luteinizing hormone releasing hormone neurones to neurotrophic factors.

    PubMed

    Gallo, F; Morale, M C; Tirolo, C; Testa, N; Farinella, Z; Avola, R; Beaudet, A; Marchetti, B

    2000-10-01

    The participation of growth factors (GFs) in the regulation of luteinizing hormone releasing hormone (LHRH) neuronal function has recently been proposed, but little is known about the role played by GFs during early LHRH neurone differentiation. In the present study, we have used combined biochemical and morphological approaches to study the ability of a number of GFs normally expressed during brain development, including basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), insulin and insulin-like growth factor I (IGF-I) to induce survival, differentiation, proliferation, and phenotypic expression of immortalized (GT1-1) LHRH neurones in vitro, at early (3-days in vitro, 3-DIV) and late (8-DIV) stages of neuronal differentiation. Comparison of GF-treated vs untreated neurones grown in serum-deprived (SD) medium demonstrated bFGF to be the most potent, and insulin the least active in promoting neuronal differentiation. Thus, at both 3-DIV and 8-DIV, but especially at 8-DIV, bFGF induced the greatest increase in the total length and number of LHRH processes/cell and in growth cone surface area. bFGF was also the most active at 3-DIV, and IGF-I at 8-DIV, in counteracting SD-induced cell death, whereas EGF was the most potent in increasing [3H]thymidine incorporation. All GFs studied decreased the spontaneous release of LHRH from GT1-1 cells when applied at 3-DIV or 8-DIV, except for insulin which was inactive at both time-points and bFGF which was inactive at 8-DIV. Pre-treatment of GT1-1 cells with a suboptimal ('priming') dose of bFGF for 12 h followed by application of the different GFs induced a sharp potentiation of the neurotrophic and proliferative effects of the latter and particularly of those of IGF-I. Moreover, bFGF priming counteracted EGF-induced decrease in LHRH release and significantly stimulated LHRH secretion following IGF-I or insulin application, suggesting that bFGF may sensitize LHRH neurones to differentiating effects of

  5. In situ injury-induced release of basic-fibroblast growth factor from corneal epithelial cells.

    PubMed Central

    Adamis, A. P.; Meklir, B.; Joyce, N. C.

    1991-01-01

    Basic-fibroblast growth factor (b-FGF) binds to heparan sulfate proteoglycan in Bowman's layer of the cornea. The mechanism by which the molecule is deposited in Bowman's layer is the subject of controversy since b-FGF lacks a signal peptide sequence for extracellular secretion. Using immunofluorescence, the authors studied the presence and distribution of b-FGF in the bovine cornea and the conditions under which it could be released and bound to Bowman's layer. The results indicate that corneal epithelium contains b-FGF but that uninjured corneas do not contain detectable levels of b-FGF in Bowman's layer. Injury to the corneal epithelium results in the binding of b-FGF to Bowman's layer. Removal of the intact corneal epithelium without cell injury does not result in the binding of b-FGF to Bowman's layer. These findings suggest that one mechanism for the release of b-FGF from corneal epithelial cells is passive leakage after cell injury with secondary binding to Bowman's layer. Images Figure 1 Figure 2 Figure 3 PMID:1951634

  6. Tailored design of electrospun composite nanofibers with staged release of multiple angiogenic growth factors for chronic wound healing.

    PubMed

    Lai, Huan-Ju; Kuan, Chen-Hsiang; Wu, Hsi-Chin; Tsai, Jui-Che; Chen, Tim-Mo; Hsieh, Dar-Jen; Wang, Tzu-Wei

    2014-10-01

    The objective of this research study is to develop a collagen (Col) and hyaluronic acid (HA) inter-stacking nanofibrous skin equivalent substitute with the programmable release of multiple angiogenic growth factors (vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) and endothelial growth factor (EGF)) either directly embedded in the nanofibers or encapsulated in the gelatin nanoparticles (GNs) by electrospinning technology. The delivery of EGF and bFGF in the early stage is expected to accelerate epithelialization and vasculature sprouting, while the release of PDGF and VEGF in the late stage is with the aim of inducing blood vessels maturation. The physiochemical characterizations indicate that the Col-HA-GN nanofibrous membrane possesses mechanical properties similar to human native skin. The design of a particle-in-fiber structure allows growth factors for slow controlled release up to 1month. Cultured on biodegradable Col-HA membrane with four kinds of growth factors (Col-HA w/4GF), endothelial cells not only increase in growth rate but also form a better network with a thread-like tubular structure. The therapeutic effect of Col-HA w/4GF membrane on streptozotocin (STZ)-induced diabetic rats reveals an accelerated wound closure rate, together with elevated collagen deposition and enhanced maturation of vessels, as revealed by Masson's trichrome stain and immunohistochemical analysis, respectively. From the above, the electrospun Col-HA-GN composite nanofibrous skin substitute with a stage-wise release pattern of multiple angiogenic factors could be a promising bioengineered construct for chronic wound healing in skin tissue regeneration.

  7. Neuroprotection elicited by nerve growth factor and brain-derived neurotrophic factor released from astrocytes in response to methylmercury.

    PubMed

    Takemoto, Takuya; Ishihara, Yasuhiro; Ishida, Atsuhiko; Yamazaki, Takeshi

    2015-07-01

    The protective roles of astrocytes in neurotoxicity induced by environmental chemicals, such as methylmercury (MeHg), are largely unknown. We found that conditioned medium of MeHg-treated astrocytes (MCM) attenuated neuronal cell death induced by MeHg, suggesting that astrocytes-released factors can protect neuronal cells. The increased expression of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) was observed in MeHg-treated astrocytes. NGF and BDNF were detected in culture media as homodimers, which are able to bind specific tyrosine kinase receptors, tropomyosin related kinase (Trk) A and TrkB, respectively. The TrkA antagonist and TrkB antagonist abolished the protective effects of MCM in neuronal cell death induced by MeHg. Taken together, astrocytes synthesize and release NGF and BDNF in response to MeHg to protect neurons from MeHg toxicity. This study is considered to show a novel defense mechanism against MeHg-induced neurotoxicity.

  8. The portal-drained viscera release fibroblast growth factor 19 in humans.

    PubMed

    Koelfat, Kiran V K; Bloemen, Johanne G; Jansen, Peter L M; Dejong, Cornelis H C; Schaap, Frank G; Olde Damink, Steven W M

    2016-12-01

    Fibroblast growth factor 19 (FGF19) is an ileum-derived endrocrine factor that is produced in response to transepithelial bile salt flux. FGF19 represses bile salt synthesis in the liver. Despite the general assumption that FGF19 signals to the liver via portal blood, no human data are available to support this notion. The aim was to study portal FGF19 levels, and determined bile salt and FGF19 fluxes across visceral organs in humans. Bile salt and FGF19 levels were assessed in arterial, portal, and hepatic venous blood collected from fasted patients who underwent partial liver resection for colorectal liver metastases (n = 30). Fluxes across the portal-drained viscera (PDV), liver, and splanchnic area were calculated. Portal bile salt levels (7.8 [5.0-12.4] μmol/L) were higher than levels in arterial (2.7 [1.7-5.5] μmol/L, P < 0.0001) and hepatic venous blood (3.4 [2.5-6.5] μmol/L, P < 0.0001). Bile salts released by the PDV (+1.2 [+0.7-+2.0] mmol kg(-1) h(-1), P < 0.0001) were largely taken up by the liver (-1.0 [-1.8 to -0.4] mmol kg(-1) h(-1), P < 0.0001). Portal levels of FGF19 (161 ± 78 pg/mL) were higher than arterial levels (135 ± 65 pg/mL, P = 0.046). A net release of FGF19 by the PDV (+4.0 [+2.1 to +9.9] ng kg(-1) h(-1), P < 0.0001) was calculated. There was no significant flux of FGF19 across the liver (-0.2 [-3.7 to +7.4] ng kg(-1) h(-1), P = 0.93). In conclusion, FGF19 levels in human portal blood are higher than in arterial blood. FGF19 is released by the portal-drained viscera under fasted steady state conditions.

  9. Detecting transforming growth factorrelease from liver cells using an aptasensor integrated with microfluidics.

    PubMed

    Matharu, Zimple; Patel, Dipali; Gao, Yandong; Haque, Amranul; Zhou, Qing; Revzin, Alexander

    2014-09-02

    We developed a cell-culture/biosensor platform consisting of aptamer-modified Au electrodes integrated with reconfigurable microfluidics for monitoring of transforming growth factor-beta 1 (TGF-β1), an important inflammatory and pro-fibrotic cytokine. Aptamers were thiolated, labeled with redox reporters, and self-assembled on gold surfaces. The biosensor was determined to be specific for TGF-β1 with an experimental detection limit of 1 ng/mL and linear range extending to 250 ng/mL. Upon determining figures of merit, aptasensor was miniaturized and integrated with human hepatic stellate cells inside microfluidic devices. Reconfigurable microfluidics were developed to ensure that seeding of "sticky" stromal cells did not foul the electrode and compromise sensor performance. This microsystem with integrated aptasensors was used to monitor TGF-β1 release from activated stellate cells over the course of 20 h. The electrochemical response went down upon infusing anti-TGF-β1 antibodies into the microfluidic devices containing activated stellate cells. To further validate aptasensor responses, stellate cells were stained for markers of activation (e.g., alpha smooth muscle actin) and were also tested for presence of TGF-β1 using enzyme linked immunosorbent assay (ELISA). Given the importance of TGF-β1 as a fibrogenic signal, a microsystem with integrated biosensors for local and continuous detection of TGF-β1 may prove to be an important tool to study fibrosis of the liver and other organs.

  10. Structural study of human growth hormone-releasing factor fragment (1?29) by vibrational spectroscopy

    NASA Astrophysics Data System (ADS)

    Carmona, P.; Molina, M.; Lasagabaster, A.

    1995-05-01

    The conformational structure of fragment 1-29 of human growth hormone releasing factor, hGHRF (1-29), in aqueous solution and in the solid state is investigated by infrared and Raman spectroscopy. The polypeptide backbone is found to be unordered in the solid state. However, the spectra of the peptide prepared as 5% (w/w) aqueous solutions show that approximately 28% of the peptide is involved in intermolecular β-sheet aggregation. The remainder of the peptide exists largely as disordered and β-sheet conformations with a small portion of α-helices. Tyrosine residues are found to be exposed to the solvent. The secondary structures are quantitatively examined through infrared spectroscopy, the conformational percentages being near those obtained by HONDAet al. [ Biopolymers31, 869 (1991)] using circular dichroism. The fast hydrogen/deuterium exchange in peptide groups and the absence of any NMR sign indicative of ordered structure [ G. M. CLOREet al., J. Molec. Biol.191, 553 (1986)] support that the solution conformations of the non-aggregated peptide interconvert in dynamic equilibrium. Some physiological advantages that may derive from this conformational flexibility are also discussed

  11. Spectroscopic studies on the conformational transitions of a bovine growth hormone releasing factor analog

    NASA Astrophysics Data System (ADS)

    Sarver, Ronald W.; Friedman, Alan R.; Thamann, Thomas J.

    1997-10-01

    The secondary structure of the bovine growth hormone releasing factor analog, [Ile 2, Ser 8,28, Ala 15, Leu 27, Hse 30] bGRF(1-30)-NH-Ethyl, acetate salt (U-90699F) was studied in solution by Fourier transform infrared and Raman spectroscopies. Spectroscopic studies revealed that concentrated aqueous solutions of U-90699F (100 mg ml -1) undergo a secondary structure transition from disordered coil/α-helix to intermolecular β-sheet. Disordered coil and α-helical structure were grouped together in the infrared and Raman studies since the amide I vibrations are close in frequency and overlap in assignments was possible. Before the conformational transition, the facile exchange of the peptide's amide hydrogens for deuterium indicated that the majority of amide hydrogens were readily accessible to solvent. The kinetics of the conformational transition coincided with an increase in solution viscosity and turbidity. An initiation phase preceded the conformational transition during which only minor spectral changes were observed by infrared spectroscopy. The initiation phase and reaction kinetics were consistent with a highly cooperative nucleation ultimately leading to a network of intermolecular β-sheet structure and gel formation. Increased temperature accelerated the conformational transition. The conformational transition was thermally irreversible but the β-sheet structure of aggregated or gelled peptide could be disrupted by dilution and agitation.

  12. Platelet-rich plasma stimulated by pulse electric fields: Platelet activation, procoagulant markers, growth factor release and cell proliferation.

    PubMed

    Frelinger, A L; Torres, A S; Caiafa, A; Morton, C A; Berny-Lang, M A; Gerrits, A J; Carmichael, S L; Neculaes, V B; Michelson, A D

    2016-01-01

    Therapeutic use of activated platelet-rich plasma (PRP) has been explored for wound healing, hemostasis and antimicrobial wound applications. Pulse electric field (PEF) stimulation may provide more consistent platelet activation and avoid complications associated with the addition of bovine thrombin, the current state of the art ex vivo activator of therapeutic PRP. The aim of this study was to compare the ability of PEF, bovine thrombin and thrombin receptor activating peptide (TRAP) to activate human PRP, release growth factors and induce cell proliferation in vitro. Human PRP was prepared in the Harvest SmartPreP2 System and treated with vehicle, PEF, bovine thrombin, TRAP or Triton X-100. Platelet activation and procoagulant markers and microparticle generation were measured by flow cytometry. Released growth factors were measured by ELISA. The releasates were tested for their ability to stimulate proliferation of human epithelial cells in culture. PEF produced more platelet-derived microparticles, P-selectin-positive particles and procoagulant annexin V-positive particles than bovine thrombin or TRAP. These differences were associated with higher levels of released epidermal growth factor after PEF than after bovine thrombin or TRAP but similar levels of platelet-derived, vascular-endothelial, and basic fibroblast growth factors, and platelet factor 4. Supernatant from PEF-treated platelets significantly increased cell proliferation compared to plasma. In conclusion, PEF treatment of fresh PRP results in generation of microparticles, exposure of prothrombotic platelet surfaces, differential release of growth factors compared to bovine thrombin and TRAP and significant cell proliferation. These results, together with PEF's inherent advantages, suggest that PEF may be a superior alternative to bovine thrombin activation of PRP for therapeutic applications.

  13. Conformational origin of a difficult coupling in a human growth hormone releasing factor analog.

    PubMed

    Deber, C M; Lutek, M K; Heimer, E P; Felix, A M

    1989-01-01

    During the solid-phase synthesis of the human growth hormone releasing factor (GRF) analog [Ala15, Leu27, Asn28] -GRF(1-32)-OH, incorporation of Boc-Gln16 was determined to be incomplete. While aggregation of growing resin-bound peptide chains with concomitant beta-sheet formation and "precipitation" has been proposed to account in general for such "difficult coupling," no feature of sequence in the Gln16 region of this GRF analog provided an immediate rationale for this result. We now report 500 MHz 1H NMR spectra of a series of resin-bound GRF segments surrounding the Gln16 position (19-32 through 14-32), swelled in dimethylsulfoxide-d6 solutions [GRF(14-32) = Leu14-Ala-Gln-Leu-Ser(Bzl)-Ala-Arg(Tos)-Lys(CIZ)-Leu- Leu-Gln-Asp(OcHex)-Ile-Leu-Asn-Arg(Tos)-Gln-Gln-Gly32-PAM resin]. While relatively sharp spectra are observed for GRF(19-32), components with resonances broadened by an order-of-magnitude appear in spectra of the 18-32 and 17-32 peptide-resin, and the entire spectrum of 16-32 is ill-resolved and highly broadened. Subsequent spectra sharpen again (15-32, 14-32). These combined synthesis/spectroscopic experimental results, in conjunction with predictive analyses using standard Chou-Fasman 2 degrees structure parameters, suggest that the completeness of the Gln16 coupling is hindered by formation of a specific, folded beta-sheet/beta-turn structure in GRF(16-32) (with the turn located at 18-21, "upstream" of the difficult coupling site), and accompanying aggregation of peptide chains. This analysis suggests that awareness of such potential beta-sheet/beta-turn sequences can guide analog choices, and/or facilitate pre-programming of synthesis steps in anticipation of problem couplings.

  14. The characterization of protein release from sericin film in the presence of an enzyme: towards fibroblast growth factor-2 delivery.

    PubMed

    Nishida, Ayumu; Naganuma, Tsuyoshi; Kanazawa, Takanori; Takashima, Yuuki; Yamada, Masaki; Okada, Hiroaki

    2011-07-29

    Aqueous preparations of silk protein (sericin) films were prepared to evaluate their biodegradation properties. In the absence of trypsin, sericin film swelled rapidly, kept its shape, and remained unaltered for 28 days or longer due to form β-sheet structures. In the presence of trypsin, sericin film gradually degraded; since the rate depended on the concentration of trypsin, the films likely underwent enzymatic hydrolysis. Sericin film incorporating the model protein drug fluorescein isothiocyanate-albumin (FA) also gradually degraded in the presence of trypsin and resulted in the sustained release of FA for 2 weeks or longer; in contrast, FA release was quite slow in the absence of trypsin. It is expected that sericin film has potential as a biodegradable and drug-releasing carrier. To evaluate the practical applicability of sericin film for the repair of defective tissues, fibroblast growth factor-2 (FGF-2) was incorporated into sericin films and the films were implanted on skull defects in rats. Whereas FGF-2 release was suppressed in the absence of trypsin in vitro, it appears that FGF-2, immobilized by ionic interactions between sericin and FGF-2, can be sustained-released in vivo from films incorporating 2500 or 250 ng of FGF-2 to support the growth of tissue around wounds.

  15. Biodegradable-co-bioresponsive Hydrogels for Controlled Release of Growth Factor

    DTIC Science & Technology

    2003-06-01

    Nerve Growth Factor (NGF) for the treatment of Alzheimer’s disease (AD). The systems are three-dimensional crosslinked copolymers composed of a thermo...multi-functional hydrogels systems with thermo-responsive and biodegradable properties. The novel hydrogels are crosslinked copolymers composed of...N,N’-methylene-bis- acrylamide as a crosslinker, and N,N,N,N’-tetramethylethylenediamine as an accele- rator. Their compositions are summarized in

  16. Synergistic effect of sustained release of growth factors and dynamic culture on osteoblastic differentiation of mesenchymal stem cells.

    PubMed

    Della Porta, Giovanna; Nguyen, Bao-Ngoc B; Campardelli, R; Reverchon, Ernesto; Fisher, John P

    2015-06-01

    Microparticles have been utilized as delivery vehicles of soluble factors to modify cellular behavior and therefore enhance tissue engineering regeneration. When incorporated into three-dimensional systems, microparticles can provide geometrical and temporal controlled release of bioactive agents, such as growth factors (GFs) to surrounding cells. This study investigates the effect of GFs release from biopolymer microparticles on osteoblastic differentiation of human mesenchymal stem cells (hMSCs) encapsulated in calcium (Ca)-alginate scaffolds while cultured in a tubular perfusion system bioreactor system. Empirical and deterministic models were used to demonstrate that poly(D,L-lactic-co-glycolic acid)-encapsulated GFs would result in a delayed release profile compared to GFs encapsulated into scaffolds directly. We hypothesized that the dual delivery of human bone-morphogenetic protein 2 (hBMP2) and human vascular endothelial growth factor to cells in dynamic culture would provide molecular and physical cues to promote differentiation. Results indicated that the exposures of hBMP2 and dynamic flow are sufficient in enhancing the osteoblastic differentiation pathway compared to no GF addition and static culture. The GF delivery system in a dynamic flow environment resulted in a synergistic effect on osteoblastic differentiation of hMSCs.

  17. Release of growth factors after mechanical and chemical pleurodesis for treatment of malignant pleural effusion: a randomized control study

    PubMed Central

    Hojski, Aljaz; Leitgeb, Maja; Crnjac, Anton

    2015-01-01

    Background Growth factors are key inducers of fibrosis but can also mediate inflammatory responses resulting in increasing pleural effusion and acute respiratory distress syndrome. The primary aim of the study was to analyse growth factors release after performing chemical and mechanical pleurodesis in the first 48 hours at the patients with malignant pleural effusion. The secondary endpoints were to evaluate the effectiveness of the both pleurodeses, symptoms release and the quality of life of patients after the treatment. Patients and methods. A prospective randomized study included 36 consecutive female patients with breast carcinoma and malignant pleural effusion in an intention-to-treat analysis. We treated 18 patients by means of thoracoscopic mechanical pleurodesis and 18 patients by chemical pleurodesis with talcum applied over a chest tube. We gathered the pleural fluid and serum samples in the following 48 hours under a dedicated protocol and tested them for growth factors levels. A quality of life and visual analogue pain score surveys were also performed. Results Median measured serum vascular endothelial growth factor (VEGF) level after chemical pleurodesis was 930.68 pg/ml (95% CI: 388.22–4656.65) and after mechanical pleurodesis 808.54 pg/ml. (95% CI: 463.20-1235.13) (p = 0.103). Median pleural levels of transforming growth factor (TGF) β1 were higher after performing mechanical pleurodesis (4814.00 pg/ml [95% CI: 2726.51–7292.94]) when compared to those after performing chemical pleurodesis (1976.50 pg/ml [95% CI: 1659.82–5136.26]) (p = 0.078). We observed similar results for fibroblast growth factor (FGF) β; the serum level was higher after mechanical pleurodesis (30.45 pg/ml [95% CI: 20.40–59.42]), compared to those after chemical pleurodesis (13.39 pg/ml [95% CI: 5.04 – 74.60]) (p = 0.076). Mechanical pleurodesis was equally effective as chemical pleurodesis in terms of hospital stay, pleural effusion re-accumulation, requiring of

  18. Efficacy of engineered FVIII-producing skeletal muscle enhanced by growth factor-releasing co-axial electrospun fibers.

    PubMed

    Liao, I-Chien; Leong, Kam W

    2011-02-01

    Co-axial electrospun fibers can offer both topographical and biochemical cues for tissue engineering applications. In this study, we demonstrate the sustained treatment of hemophilia through a non-viral, tissue engineering approach facilitated by growth factor-releasing co-axial electrospun fibers. FVIII-producing skeletal myotubes were first engineered on aligned electrospun fibers in vitro, followed by implantation in hemophilic mice with or without a layer of core-shell electrospun fibers designed to provide sustained delivery of angiogenic or lymphangiogenic growth factors, which serves to stimulate the lymphatic or vascular systems to enhance the FVIII transport from the implant site into systemic circulation. Upon subcutaneous implantation into hemophilic mice, the construct seamlessly integrated with the host tissue within one month, and specifically induced either vascular or lymphatic network infiltration in accordance with the growth factors released from the electrospun fibers. Engineered constructs that induced angiogenesis resulted in sustained elevation of plasma FVIII and significantly reduced blood coagulation time for at least 2-months. Biomaterials-assisted functional tissue engineering was shown in this study to offer protein replacement therapy for a genetic disorder such as hemophilia.

  19. A tubular gelatin scaffold capable of the time-dependent controlled release of epidermal growth factor and mitomycin C.

    PubMed

    Zhu, Jixiang; Yang, Fanwen; He, Fupo; Tian, Xiumei; Tang, Shuo; Chen, Xiaoming

    2015-11-01

    A tubular gelatin scaffold for the time-dependent controlled release of epidermal growth factor (EGF) and mitomycin C (MMC) was fabricated. EGF was incorporated using silk fibroin carriers, and MMC was planted using polylactide (PLA) microspheres. The relationship between scaffold properties and crosslinking degrees was evaluated. As the crosslinking degree was increased from 23.7% to 65.3%, the mechanical properties of the scaffold obviously improved, and the compressive modulus increased to approximately 65kPa. The mass degradation of the scaffold was also controlled from 9 days to approximately 1 month. In vitro release tests indicated that the scaffold mainly released EGF in the early period and MMC in the later period. Urethral epithelial cells (UECs) and urethral scar derived fibroblast cells (UFCs) were coseeded in the scaffold at a ratio of 1:1. After 9 days of coculture, immunostaining results displayed that the proportion of UECs continuously increased to approximately 71%. These changes in cell proportion were confirmed by the results of Western blot analysis. Therefore, the scaffold promoted the growth but inhibited the regeneration of UFCs. This scaffold for time-dependent controlled release of multiple biofactors may be potentially useful in urethral reconstruction and other tissue engineering studies.

  20. HB-EGF release mediates glucose-induced activation of the epidermal growth factor receptor in mesangial cells.

    PubMed

    Uttarwar, L; Peng, F; Wu, D; Kumar, S; Gao, B; Ingram, A J; Krepinsky, J C

    2011-04-01

    Glomerular matrix accumulation is a hallmark of diabetic nephropathy. We showed that transactivation of the epidermal growth factor receptor (EGFR) is an important mediator of matrix upregulation in mesangial cells (MC) in response to high glucose (HG). Here, we study the mechanism of EGFR transactivation. In primary MC, EGFR transactivation by 1 h of HG (30 mM) was unaffected by inhibitors of protein kinase C, reactive oxygen species, or the angiotensin II AT1 receptor. However, general metalloprotease inhibition, as well as specific inhibitors of heparin-binding EGF-like growth factor (HB-EGF), prevented both EGFR and downstream Akt activation. HB-EGF was released into the medium by 30 min of HG, and this depended on metalloprotease activity. One of the metalloproteases shown to cleave proHB-EGF is ADAM17 (TACE). HG, but not an osmotic control, activated ADAM17, and its inhibition prevented EGFR and Akt activation and HB-EGF release into the medium. siRNA to either ADAM17 or HB-EGF prevented HG-induced EGFR transactivation. We previously showed that EGFR/Akt signaling increases transforming growth factor (TGF)-β1 transcription through the transcription factor activator protein (AP)-1. HG-induced AP-1 activation, as assessed by EMSA, was abrogated by inhibitors of metalloproteases, HB-EGF and ADAM17. HB-EGF and ADAM17 siRNA also prevented AP-1 activation. Finally, these inhibitors and siRNA prevented TGF-β1 upregulation by HG. Thus, HG-induced EGFR transactivation in MC is mediated by the release of HB-EGF, which requires activity of the metalloprotease ADAM17. The mechanism of ADAM17 activation awaits identification. Targeting upstream mediators of EGFR transactivation including HB-EGF or ADAM17 provides novel therapeutic targets for the treatment of diabetic nephropathy.

  1. Basic fibroblast growth factor binds to subendothelial extracellular matrix and is released by heparitinase and heparin-like molecules

    SciTech Connect

    Bashkin, P.; Doctrow, S.; Klagsbrun, M.; Svahn, C.M.; Folkman, J.; Vlodavsky, I. )

    1989-02-21

    Basic fibroblast growth factor (bFGF) exhibits specific binding to the extracellular matrix (ECM) produced by cultured endothelial cells. Binding was saturable as a function both of time and of concentration of {sup 125}I-bFGF. Scatchard analysis of FGF binding revealed the presence of about 1.5 x 10{sup 12} binding sites/mm{sup 2} ECM with an apparent k{sub D} of 610 nM. FGF binds to heparan sulfate (HS) in ECM as evidenced by (i) inhibition of binding in the presence of heparin or HS at 0.1-1 {mu}g/mL, but not by chondroitin sulfate, keratan sulfate, or hyaluronic acid at 10 {mu}g/mL, (ii) lack of binding to ECM pretreated with heparitinase, but not with chondroitinase ABC, and (iii) rapid release of up to 90% of ECM-bound FGF by exposure to heparin, HS, or heparitinase, but not to chondroitin sulfate, keratan sulfate, hyaluronic acid, or chondroitinase ABC. Oligosaccharides derived from depolymerized heparin, and as small as the tetrasaccharide, released the ECM-bound FGF, but there was little or no release of FGF by modified nonanticoagulant heparins such as totally desulfated heparin, N-desulfated heparin, and N-acetylated heparin. FGF released from ECM was biologically active, as indicated by its stimulation of cell proliferation and DNA synthesis in vascular endothelial cells and 3T3 fibroblasts. Similar results were obtained in studies on release of endogenous FGF-like mitogenic activity from Descement's membranes of bovine corneas. It is suggested that ECM storage and release of bFGF provide a novel mechanism for regulation of capillary blood vessel growth. Whereas ECM-bound FGF may be prevented from acting on endothelial cells, its displacement by heparin-like molecules and/or HS-degrading enzymes may elicit a neovascular response.

  2. Sequential antibiotic and growth factor releasing chitosan-PAAm semi-IPN hydrogel as a novel wound dressing.

    PubMed

    Pulat, Mehlika; Kahraman, Anıl Sera; Tan, Nur; Gümüşderelioğlu, Menemşe

    2013-01-01

    The aim of this study is to prepare a novel wound dressing material which provides burst release of an antibiotic in combination with sustained release of growth factor delivery. This might be beneficial for the prevention of infections and to stimulate wound healing. As a wound dressing material, the semi-interpenetrating network (semi-IPN) hydrogel based on polyacrylamide (PAAm) and chitosan (CS) was synthesized via free radical polymerization. Ethylene glycol dimethacrylate was used for cross-linking of PAAm to form semi-IPN hydrogel. The hydrogel shows high water content (∼1800%, in dry basis) and stable swelling characteristics in the pH range of the wound media (∼4.0-7.4). The antibiotic, piperacillin-tazobactam, which belongs to the penicillin group was loaded into the hydrogel. The therapeutic serum dose of piperacillin-tazobactam for topic introduction was reached at 1st hour of the release. Additionally, in order to increase the mitogenic activity of hydrogel, epidermal growth factor (EGF) was embedded into the CS-PAAm in different amounts. Cell culture studies were performed with L929 mouse fibroblasts and the simulated cell growth was investigated by 3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide assay. The successful sustained release behavior of CS-PAAm hydrogel for EGF maintained the presence of EGF in the culture up to 5 days and the highest mitochondrial activities were recorded for the 0.4 μg EGF-loaded/mg of hydrogel group. In conclusion, CS-PAAm semi-IPN hydrogel loaded with piperacillin-tazobactam and EGF could be proposed for an effective system in wound-healing management.

  3. Specific Adsorption via Peptide Tags: Oriented Grafting and Release of Growth Factors for Tissue Engineering.

    PubMed

    Murschel, Frederic; Zaimi, Aldo; Noel, Samantha; Jolicoeur, Mario; De Crescenzo, Gregory

    2015-11-09

    Numerous strategies have been proposed to decorate biomaterials with growth factors (GFs) for tissue engineering applications; their practicability as clinical tools, however, remains uncertain. We previously presented two complementary amphipathic peptides, namely, E5 and K5, which could be utilized as tags to direct GF capture onto organic materials via E5/K5 coiled-coil interactions. We here investigated their potential as mediators of GF physical adsorption. Enzyme-linked immunosorbent assays highlighted that both electrostatic and hydrophobic interactions could contribute to the adsorption process, without interfering with the peptides propensity for coiled-coil interactions. E5-tagged vascular endothelial growth factor, in particular, was efficiently adsorbed to poly(allylamine)-functionalized polystyrene, was maintained in a bioactive state and was steadily liberated over several days with little initial burst. This simple immobilization procedure was successfully applied to poly(ethylene terephthalate) films. Altogether, our data demonstrated that coil-tag-directed adsorption is a tunable, versatile and straightforward strategy to decorate biomaterials with GFs.

  4. Effects of growth hormone-releasing factor on growth hormone response, growth and feed conversion efficiency in buffalo heifers (Bubalus bubalis).

    PubMed

    Haldar, A; Prakash, B S

    2007-09-01

    The aim of this study was to determine the benefits of growth hormone-releasing factor (GRF) on growth and feed conversion efficiency (FCE) in buffaloes. Twelve Murrah buffalo heifers (Bubalus bubalis) of mean age 24.8 months and mean body weight 302.4kg were divided into two groups (treatment and control) with six animals in each group. The buffaloes were given intravenous injections of bovine GRF (bGRF) at a dose rate of 10microg/100kg body weight or an equal volume of saline at 15-day intervals for a period of 9 months. Plasma growth hormone (GH) responses to bGRF challenge were measured in blood samples collected at 90-day intervals on days 1, 90, 180 and 270 and samples were taken at -60, -30, 0, +10, +20, +30, +60, +120 and +180min relative to bGRF injection. Blood samples were also collected weekly by jugular venepuncture for the quantification of plasma GH. The average growth rate (AGR) and FCE of all animals were recorded at 15-day intervals. Plasma GH concentrations increased (P=0.001) steadily following bGRF challenge, peaking 10-20min after challenge and declining to baseline by 180min. In the treatment group, there were no significant differences (P>0.05) in either the peak heights of the GH response or the area under the curve (AUC) of the GH response after bGRF challenge on any of the four occasions of intensive bleeding. There were overall increases in plasma GH concentrations (P<0.01), AGR (P<0.01) and FCE (P=0.05) in the treatment group compared with the control animals. The study showed that GH responsiveness to administration of bGRF at 15-day intervals over 9 months of treatment remained unchanged in buffalo heifers. Exogenous bGRF treatment for a long period can therefore enhance GH release leading to higher growth rates and better feed conversion efficiency in buffalo heifers.

  5. Direct effects of growth hormone (GH)-releasing hexapeptide (GHRP-6) and GH-releasing factor (GRF) on GH secretion from cultured porcine somatotropes.

    PubMed

    Sánchez-Hormigo, A; Castaño, J P; Torronteras, R; Malagón, M M; Ramírez, J L; Gracia-Navarro, F

    1998-01-01

    Growth hormone (GH)-releasing hexapeptide (GHRP-6) belongs to the expanding family of synthetic GH secretagogues (GHSs). Previous studies have shown that non-peptidyl GHRP-6 analogues stimulate GH release in vivo in pigs, and interact synergistically with GH-releasing factor (GRF), but its direct effects on porcine somatotropes have not been addressed hitherto. In the present study, we have evaluated the response of cultured porcine pituitary cells to GHRP-6, and its interaction with GRF and somatostatin (SRIF). Secretory response of somatotropes was assessed by using two distinct techniques. GH released by monolayer cell cultures was evaluated by enzyme immunoassay, whereas that secreted by individual somatotropes was measured by immunodensitometry using a cell blotting assay. Our results demonstrate that both GHRP-6 and GRF stimulated GH release from monolayer cultures at doses equal to or above 10(-9) M. Use of cell immunoblot assay demonstrated that, like GRF, the hexapeptide acts directly upon porcine somatotropes to exert its action. Moreover, regardless of the technique applied, combined administration of GHRP-6 (10(-6) or 10(-9) M) and GRF (10(-8) M) resulted in an additive, but not synergistic, stimulatory GH response. Finally, SRIF (10(-7) M) inhibited the stimulatory effect of GHRP-6 alone or in combination with GRF. These results indicate that GHRP-6 directly and effectively stimulates GH secretion from porcine somatotropes in vitro, and acts additively when coadministered with GRF. Therefore, the synergistic stimulatory effect of GHSs and GRF reported in vivo in this species might require additional factors that are lacking in the in vitro situation.

  6. Transforming growth factor Beta-releasing scaffolds for cartilage tissue engineering.

    PubMed

    Madry, Henning; Rey-Rico, Ana; Venkatesan, Jagadeesh K; Johnstone, Brian; Cucchiarini, Magali

    2014-04-01

    The maintenance of a critical threshold concentration of transforming growth factor beta (TGF-β) for a given period of time is crucial for the onset and maintenance of chondrogenesis. Thus, the development of scaffolds that provide temporal and/or spatial control of TGF-β bioavailability has appeal as a mechanism to induce the chondrogenesis of stem cells in vitro and in vivo for articular cartilage repair. In the past decade, many types of scaffolds have been designed to advance this goal: hydrogels based on polysaccharides, hyaluronic acid, and alginate; protein-based hydrogels such as fibrin, gelatin, and collagens; biopolymeric gels and synthetic polymers; and solid and hybrid composite (hydrogel/solid) scaffolds. In this study, we review the progress in developing strategies to deliver TGF-β from scaffolds with the aim of enhancing chondrogenesis. In the future, such scaffolds could prove critical for tissue engineering cartilage, both in vitro and in vivo.

  7. Chitosan scaffold enhances growth factor release in wound healing in von Willebrand disease

    PubMed Central

    Periayah, Mercy Halleluyah; Halim, Ahmad Sukari; Saad, Arman Zaharil Mat; Yaacob, Nik Soriani; Hussein, Abdul Rahim; Karim, Faraizah Abdul; Rashid, Ahmad Hazri Abdul; Ujang, Zanariah

    2015-01-01

    Chitosan-derived biomaterials have been reported to adhere when in contact with blood by encouraging platelets to adhere, activate and aggregate at the sites of vascular injury, thus enhanced wound healing capacity. This study investigated platelet morphology changes and the expression level of transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor-AB (PDGF-AB) in the adherence of two different types of chitosans in von Willebrand disease (vWD): N,O-carboxymethylchitosan (NO-CMC) and oligo-chitosan (O-C). Fourteen vWD voluntary subjects were recruited, and they provided written informed consent. Scanning electron microscopy and enzyme-linked immunosorbent assay test procedures were employed to achieve the objective of the study. The results suggest that the O-C group showed dramatic changes in the platelet’s behaviors. Platelets extended filopodia and generated lamellipodia, leading to the formation of grape-like shaped aggregation. The platelet aggregation occurred depending on the severity of vWD. O-C was bound to platelets on approximately 90% of the surface membrane in vWD type 1; there was 70% and 50% coverage in vWD type II and III, respectively. The O-C chitosan group showed an elevated expression level of TGF-β1 and PDGF-AB. This finding suggests that O-C stimulates these mediators from the activated platelets to the early stage of restoring the damaged cells and tissues. This study demonstrated that the greater expression level of O-C assists in mediating the cytokine complex networks of TGF-β1 and PDGF-AB and induces platelet activities towards wound healing in vWD. With a better understanding of chitosan’s mechanisms of action, researchers are able to accurately develop novel therapies to prevent hemorrhage. PMID:26629055

  8. Cell Injury-Induced Release of Fibroblast Growth Factor 2: Relevance to Intracerebral Mesenchymal Stromal Cell Transplantations

    PubMed Central

    Vinodkumar, Deepti; McGrogan, Michael; Bates, Damien

    2015-01-01

    Beneficial effects of intracerebral transplantation of mesenchymal stromal cells (MSC) and their derivatives are believed to be mediated mostly by factors produced by engrafted cells. However, the mesenchymal cell engraftment rate is low, and the majority of grafted cells disappear within a short post-transplantation period. Here, we hypothesize that dying transplanted cells can affect surrounding tissues by releasing their active intracellular components. To elucidate the type, amounts, and potency of these putative intracellular factors, freeze/thaw extracts of MSC or their derivatives were tested in enzyme-linked immunosorbent assays and bioassays. We found that fibroblast growth factor (FGF)2 and FGF1, but not vascular endothelial growth factor and monocyte chemoattractant protein 1 levels were high in extracts despite being low in conditioned media. Extracts induced concentration-dependent proliferation of rat cortical neural progenitor cells and human umbilical vein endothelial cells; these proliferative responses were specifically blocked by FGF2-neutralizing antibody. In the neuropoiesis assay with rat cortical cells, both MSC extracts and killed cells induced expression of nestin, but not astrocyte differentiation. However, suspensions of killed cells strongly potentiated the astrogenic effects of live MSC. In transplantation-relevant MSC injury models (peripheral blood cell-mediated cytotoxicity and high cell density plating), MSC death coincided with the release of intracellular FGF2. The data showed that MSC contain a major depot of active FGF2 that is released upon cell injury and is capable of acutely stimulating neuropoiesis and angiogenesis. We therefore propose that both dying and surviving grafted MSC contribute to tissue regeneration. PMID:25873141

  9. Live Staphylococcus aureus Induces Expression and Release of Vascular Endothelial Growth Factor in Terminally Differentiated Mouse Mast Cells.

    PubMed

    Johnzon, Carl-Fredrik; Rönnberg, Elin; Guss, Bengt; Pejler, Gunnar

    2016-01-01

    Mast cells have been shown to express vascular endothelial growth factor (VEGF), thereby implicating mast cells in pro-angiogenic processes. However, the mechanism of VEGF induction in mast cells and the possible expression of VEGF in fully mature mast cells have not been extensively studied. Here, we report that terminally differentiated peritoneal cell-derived mast cells can be induced to express VEGF in response to challenge with Staphylococcus aureus, thus identifying a mast cell-bacteria axis as a novel mechanism leading to VEGF release. Whereas live bacteria produced a robust upregulation of VEGF in mast cells, heat-inactivated bacteria failed to do so, and bacteria-conditioned media did not induce VEGF expression. The induction of VEGF was not critically dependent on direct cell-cell contact between bacteria and mast cells. Hence, these findings suggest that VEGF can be induced by soluble factors released during the co-culture conditions. Neither of a panel of bacterial cell-wall products known to activate toll-like receptor (TLR) signaling promoted VEGF expression in mast cells. In agreement with the latter, VEGF induction occurred independently of Myd88, an adaptor molecule that mediates the downstream events following TLR engagement. The VEGF induction was insensitive to nuclear factor of activated T-cells inhibition but was partly dependent on the nuclear factor kappa light-chain enhancer of activated B cells signaling pathway. Together, these findings identify bacterial challenge as a novel mechanism by which VEGF is induced in mast cells.

  10. Paracrine effects of bombesin/gastrin-releasing peptide and other growth factors on pulmonary neuroendocrine cells in vitro.

    PubMed

    Speirs, V; Bienkowski, E; Wong, V; Cutz, E

    1993-05-01

    Pulmonary neuroendocrine cells (PNEC) are numerous in the fetus where they have been implicated to have a role in fetal lung development. We assessed the effects of putative growth factors, gastrin releasing peptide (GRP), cholecystokinin (CCK), gastrin (GN), serotonin (5-HT), and epidermal growth factor (EGF), some of which are produced by PNEC, either alone or in combination, on cultured fetal rabbit PNEC from 20, 24, and 28 day fetuses. GRP increased the total protein of the cultures over a 7 day period in an age-dependent manner, with greatest effect in cultures from the 24 day fetus, no effect with the 28 day fetus, and an inhibitory effect on 20 day cultures. This was accompanied by an increase in PNEC, which could be blocked by treatment of the cultures with a monoclonal antibody to GRP (2A11). There was no increase in 3H-thymidine labeling of PNEC in GRP treated cultures but an increase in numbers of cells partially stained for 5-HT, suggesting the induction of a precursor cell. Other growth factors had neither an inhibitory nor a stimulatory effect either alone or in combination with GRP. Preliminary studies with 125I-GRP receptor localization suggests that the GRP receptor is mostly expressed on pulmonary fibroblasts, and less on epithelial cells, so that the role for GRP in fetal lung development, at least in the rabbit, is probably indirect, acting via a paracrine mechanism.

  11. Brain changes in Alzheimer's disease patients with implanted encapsulated cells releasing nerve growth factor.

    PubMed

    Ferreira, Daniel; Westman, Eric; Eyjolfsdottir, Helga; Almqvist, Per; Lind, Göran; Linderoth, Bengt; Seiger, Ake; Blennow, Kaj; Karami, Azadeh; Darreh-Shori, Taher; Wiberg, Maria; Simmons, Andrew; Wahlund, Lars-Olof; Wahlberg, Lars; Eriksdotter, Maria

    2015-01-01

    New therapies with disease-modifying effects are urgently needed for treating Alzheimer's disease (AD). Nerve growth factor (NGF) protein has demonstrated regenerative and neuroprotective effects on basal forebrain cholinergic neurons in animal studies. In addition, AD patients treated with NGF have previously shown improved cognition, EEG activity, nicotinic binding, and glucose metabolism. However, no study to date has analyzed brain atrophy in patients treated with NGF producing cells. In this study we present MRI results of the first clinical trial in patients with AD using encapsulated NGF biodelivery to the basal forebrain. Six AD patients received the treatment during twelve months. Patients were grouped as responders and non-responders according to their twelve-months change in MMSE. Normative values were created from 131 AD patients from ADNI, selecting 36 age- and MMSE-matched patients for interpreting the longitudinal changes in MMSE and brain atrophy. Results at baseline indicated that responders showed better clinical status and less pathological levels of cerebrospinal fluid (CSF) Aβ1-42. However, they showed more brain atrophy, and neuronal degeneration as evidenced by higher CSF levels of T-tau and neurofilaments. At follow-up, responders showed less brain shrinkage and better progression in the clinical variables and CSF biomarkers. Noteworthy, two responders showed less brain shrinkage than the normative ADNI group. These results together with previous evidence supports the idea that encapsulated biodelivery of NGF might have the potential to become a new treatment strategy for AD with both symptomatic and disease-modifying effects.

  12. In vivo evidence for epidermal growth factor receptor (EGFR)-mediated release of prolactin from the pituitary gland.

    PubMed

    Dahlhoff, Maik; Blutke, Andreas; Wanke, Rüdiger; Wolf, Eckhard; Schneider, Marlon R

    2011-11-11

    Members of the epidermal growth factor receptor (EGFR/ERBB) system are essential local regulators of mammary gland development and function. Emerging evidence suggests that EGFR signaling may also influence mammary gland activity indirectly by promoting the release of prolactin from the pituitary gland in a MAPK and estrogen receptor-α (ERα)-dependent manner. Here, we report that overexpression of the EGFR ligand betacellulin (BTC) causes a lactating-like phenotype in the mammary gland of virgin female mice including the major hallmarks of lactogenesis. BTC transgenic (BTC-tg) females showed reduced levels of prolactin in the pituitary gland and increased levels of the hormone in the circulation. Furthermore, treatment of BTC-tg females with bromocriptine, an inhibitor of prolactin secretion, blocked the development of the lactation-like phenotype, suggesting that it is caused by central release of prolactin rather than by local actions of BTC in the mammary gland. Introduction of the antimorphic Egfr allele Wa5 also blocked the appearance of the mammary gland alterations, revealing that the phenotype is EGFR-dependent. We detected an increase in MAPK activity, but unchanged phosphorylation of ERα in the pituitary gland of BTC-tg females as compared with control mice. These results provide the first functional evidence in vivo for a role of the EGFR system in regulating mammary gland activity by modulating prolactin release from the pituitary gland.

  13. Release of the angiogenic cytokine vascular endothelial growth factor (VEGF) from platelets: significance for VEGF measurements and cancer biology.

    PubMed

    Banks, R E; Forbes, M A; Kinsey, S E; Stanley, A; Ingham, E; Walters, C; Selby, P J

    1998-03-01

    Vascular endothelial growth factor (VEGF) is a potent angiogenic factor with a key role in several pathological processes, including tumour vascularization. Our preliminary observations indicated higher VEGF concentrations in serum samples than in matched plasma samples. We have now demonstrated that this difference is due to the presence of VEGF within platelets and its release upon their activation during coagulation. In eight healthy volunteers, serum VEGF concentrations ranged from 76 to 854 pg ml(-1) and were significantly higher (P < 0.01) than the matched citrated plasma VEGF concentrations, which ranged from < 9 to 42 pg ml(-1). Using platelet-rich plasma, mean (s.d.) platelet VEGF contents of 0.56 (0.36) pg of VEGF 10(-6) platelets were found. Immunocytochemistry demonstrated the cytoplasmic presence of VEGF within megakaryocytes and other cell types within the bone marrow. From examination of the effects of blood sample processing on circulating VEGF concentrations, it is apparent that for accurate measurements, citrated plasma processed within 1 h of venepuncture should be used. Serum is completely unsuitable. The presence of VEGF within platelets has implications for processes involving platelet and endothelial cell interactions. e.g. wound healing, and in tumour metastasis, when platelets adhering to circulating tumour cells may release VEGF at points of adhesion to endothelium, leading to hyperpermeability and extravasation of cells.

  14. Endothelial stress induces the release of vitamin D-binding protein, a novel growth factor

    SciTech Connect

    Raymond, Marc-Andre; Desormeaux, Anik; Labelle, Andree; Soulez, Mathilde; Soulez, Gilles; Langelier, Yves; Pshezhetsky, Alexey V.; Hebert, Marie-Josee . E-mail: marie-josee.hebert.chum@ssss.gouv.qc.ca

    2005-12-23

    Endothelial cells (EC) under stress release paracrine mediators that facilitate accumulation of vascular smooth muscle cells (VSCM) at sites of vascular injury. We found that medium conditioned by serum-starved EC increase proliferation and migration of VSCM in vitro. Fractionation of the conditioned medium followed by mass spectral analysis identified one bioactive component as vitamin D-binding protein (DBP). DBP induced both proliferation and migration of VSMC in vitro in association with increased phosphorylation of ERK 1/2. PD 98059, a biochemical inhibitor of ERK 1/2, abrogated these proliferative and migratory responses in VSMC. DBP is an important carrier for the vitamin-D sterols, 25-hydroxyvitamin-D, and 1{alpha},25-dihydroxyvitamin-D. Both sterols inhibited the activity of DBP on VSMC, suggesting that vitamin D binding sites are important for initiating the activities of DBP on VSMC. Release of DBP at sites of endothelial injury represents a novel pathway favoring accumulation of VSMC at sites of vascular injury.

  15. Generating favorable growth factor and protease release profiles to enable extracellular matrix accumulation within an in vitro tissue engineering environment.

    PubMed

    Zhang, Xiaoqing; Battiston, Kyle G; Labow, Rosalind S; Simmons, Craig A; Santerre, J Paul

    2017-02-24

    Tissue engineering (particularly for the case of load-bearing cardiovascular and connective tissues) requires the ability to promote the production and accumulation of extracellular matrix (ECM) components (e.g., collagen, glycosaminoglycan and elastin). Although different approaches have been attempted in order to enhance ECM accumulation in tissue engineered constructs, studies of underlying signalling mechanisms that influence ECM deposition and degradation during tissue remodelling and regeneration in multi-cellular culture systems have been limited. The current study investigated vascular smooth muscle cell (VSMC)-monocyte co-culture systems using different VSMC:monocyte ratios, within a degradable polyurethane scaffold, to assess their influence on ECM generation and degradation processes, and to elucidate relevant signalling molecules involved in this in vitro vascular tissue engineering system. It was found that a desired release profile of growth factors (e.g. insulin growth factor-1 (IGF-1)) and hydrolytic proteases (e.g. matrix-metalloproteinases 2, 9, 13 and 14 (MMP2, MMP9, MMP13 and MMP14)), could be achieved in co-culture systems, yielding an accumulation of ECM (specifically for 2:1 and 4:1 VSMC:monocyte culture systems). This study has significant implications for the tissue engineering field (including vascular tissue engineering), not only because it identified important cytokines and proteases that control ECM accumulation/degradation within synthetic tissue engineering scaffolds, but also because the established culture systems could be applied to improve the development of different types of tissue constructs.

  16. Thyroid hormone modulation of the hypothalamic growth hormone (GH)-releasing factor-pituitary GH axis in the rat.

    PubMed Central

    Miki, N; Ono, M; Hizuka, N; Aoki, T; Demura, H

    1992-01-01

    Both thyroid hormone and hypothalamic growth hormone (GH)-releasing factor (GRF) facilitate pituitary somatotroph function. However, the pathophysiological role of thyroid hormone in GRF secretion is less well understood. Thyrotoxicosis, induced by administration of thyroxine (T4) in rats, inhibited both pituitary GH levels and immunoreactive GRF secretion from incubated hypothalamus. At the highest dose of T4 given for 12 d, GRF secretion and pituitary GH decreased by 50 and 39%, respectively. Hypothyroidism induced by thyroidectomy (Tx) enhanced GRF secretion approximately twofold while depleting pituitary GH by greater than 99%. Both of these hypothalamic and pituitary effects were reversed by replacement of T4 but not human GH for 7 or 14 d. Human GH was as potent as T4 in restoring decreased body weight gains or serum insulin-like growth factor-1 levels in Tx rats. These results indicate that at both physiological and pathological concentrations in serum, thyroid hormone acts as an inhibitory modulator of GRF secretion, probably not involving a feedback mechanism through GH. A biphasic effect of thyroid hormone on pituitary GH levels appears to derive from the difference in primary target tissues of hyper- and hypothyroidism, the hypothalamus and the pituitary, respectively. PMID:1634603

  17. Incorporation of Chitosan Microspheres into Collagen-Chitosan Scaffolds for the Controlled Release of Nerve Growth Factor

    PubMed Central

    Xiao, Wei; Qi, Fengyu; Huang, Jinghui; Luo, Zhuojing

    2014-01-01

    Background Artifical nerve scaffold can be used as a promising alternative to autologous nerve grafts to enhance the repair of peripheral nerve defects. However, current nerve scaffolds lack efficient microstructure and neurotrophic support. Methods Microsphere–Scaffold composite was developed by incorporating chitosan microspheres loaded with nerve growth factor (NGF–CMSs) into collagen-chitosan scaffolds (CCH) with longitudinally oriented microchannels (NGF–CMSs/CCH). The morphological characterizations, in vitro release kinetics study, neurite outgrowth assay, and bioactivity assay were evaluated. After that, a 15-mm-long sciatic nerve gap in rats was bridged by the NGF–CMSs/CCH, CCH physically absorbed NGF (NGF/CCH), CCH or nerve autograft. 16 weeks after implantation, electrophysiology, fluoro-gold retrograde tracing, and nerve morphometry were performed. Results The NGF–CMSs were evenly distributed throughout the longitudinally oriented microchannels of the scaffold. The NGF–CMSs/CCH was capable of sustained release of bioactive NGF within 28 days as compared with others in vitro. In vivo animal study demonstrated that the outcomes of NGF–CMSs/CCH were better than those of NGF/CCH or CCH. Conclusion Our findings suggest that incorporation of NGF–CMSs into the CCH may be a promising tool in the repair of peripheral nerve defects. PMID:24983464

  18. Nitrogen balance and mineral excretion in growing male pigs injected with a human growth hormone-releasing factor analog.

    PubMed Central

    Dubreuil, P; Abribat, T; Brazeau, P; Lapierre, H

    1998-01-01

    A human growth hormone-releasing factor analog ([Desamino-Tyr1,D-Ala2,Ala15] hGRF(1-29) NH2) has been reported to reduce feed intake and increase growth and feed efficiency in a dose-dependent manner in growing pigs. The aim of this study was to determine the effect of this analog on nitrogen (N) balance and mineral excretion. Fifteen castrated male Yorkshire x Landrace pigs (45.9 +/- 1.4 kg) were randomly allotted to 2 groups: control (saline, n = 7) and GRF (6.66 micrograms/kg sc, TID, n = 8). The animals were injected for 20 consecutive days: feces and urine were collected during the last 10 d of injection. The animals had free access to water and food until satiety (approximately 15 min) at 07:00, 11:00, 15:00, 19:00, 23:00 and 07:00 h. The diet consisted of a hog fattening ration (18.0% crude protein). Blood samples were collected on the last day of the study by venipuncture. This analog increased (P < 0.05) insulin-like growth factor-1 and glucose serum concentrations and decreased (P < 0.05) serum urea nitrogen concentration and feed intake. The GRF-treated animals ingested less N, excreted less N in urine and feces to retain a similar amount of N than controls. The apparent coefficient of digestibility of the N has been slightly increased (P < 0.05) by GRF. Urinary excretion of P, K, and Cl decreased (P < 0.01) with GRF treatment. In conclusion, this GRF analog increased N digestibility and retention relative to N ingestion and reduced urinary N, P, K, and Cl excretion. PMID:9442933

  19. Three-dimensional Printed Scaffolds with Gelatin and Platelets Enhance In vitro Preosteoblast Growth Behavior and the Sustained-release Effect of Growth Factors

    PubMed Central

    Zhu, Wei; Xu, Chi; Ma, Bu-Peng; Zheng, Zhi-Bo; Li, Yu-Long; Ma, Qi; Wu, Guo-Liang; Weng, Xi-Sheng

    2016-01-01

    Background: Three-dimensional (3D) printing technology holds great promise for treating diseases or injuries that affect human bones with enhanced performance over traditional techniques. Different patterns of design can lead to various mechanical properties and biocompatibility to various degrees. However, there is still a long way to go before we can fully take advantage of 3D printing technologies. Methods: This study tailored 3D printed scaffolds with gelatin and platelets to maximize bone regeneration. The scaffolds were designed with special internal porous structures that can allow bone tissue and large molecules to infiltrate better into the scaffolds. They were then treated with gelatin and platelets via thermo-crosslinking and freeze-drying, respectively. Vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-β1 were measured at different time points after the scaffolds had been made. Cell proliferation and cytotoxicity were determined via cell counting kit-8 (CCK-8) assay. Results: There was a massive boost in the level of VEGF and TGF-β1 released by the scaffolds with gelatin and platelets compared to that of scaffolds with only gelatin. After 21 days of culture, the CCK-8 cell counts of the control group and treated group were significantly higher than that of the blank group (P < 0.05). The cytotoxicity test also indicated the safety of the scaffolds. Conclusions: Our experiments confirmed that the 3D printed scaffolds we had designed could provide a sustained-release effect for growth factors and improve the proliferation of preosteoblasts with little cytotoxicity in vitro. They may hold promise as bone graft substitute materials in the future. PMID:27779164

  20. Leptin alters the response of the growth hormone releasing factor- growth hormone--insulin-like growth factor-I axis to fasting.

    PubMed

    LaPaglia, N; Steiner, J; Kirsteins, L; Emanuele, M; Emanuele, N

    1998-10-01

    Proper nutritional status is critical for maintaining growth and metabolic function, playing an intimate role in neuroendocrine regulation. Leptin, the recently identified product of the obese gene, may very well be an integral signal which regulates neuroendocrine responses in times of food deprivation. The present study examines leptin's ability to regulate hormonal synthesis and secretion within the GRF-GH-IGF axis in the adult male rat during almost 3 days of fasting. Serum levels of GH and IGF-I were drastically suppressed by fasting. Daily leptin administration was able to fully prevent the fasting-induced fall in serum GH. Leptin failed to restore IGF-I to control levels, however, suggesting possible GH resistance. Fasting caused an insignificant increase in GH mRNA, while leptin injections significantly increased steady-state levels of this message. The GRF receptor (GRFr) message was not altered with fasting or leptin treatment. Leptin also exhibited effects at the hypothalamic level. Fasting induced a sharp fall in GRF mRNA expression and leptin injections partially prevented this fall. However, there were no observed changes in the hypothalamic GRF content. These results provide evidence that leptin may function as a neuromodulator of the GRF-GH-IGF axis communicating to this hormonal system the nutritional status of the animal.

  1. Use of osmotic pumps for subcutaneous infusion of growth hormone-releasing factors in steers and wethers.

    PubMed

    Wheaton, J E; al-Raheem, S N; Godfredson, J A; Dorn, J M; Wong, E A; Vale, W; Rivier, J; Mowles, T F; Heimer, E P; Felix, A M

    1988-11-01

    Osmotic pumps were evaluated for 7-d delivery of growth hormone-releasing factor (GRF). In Exp. 1, 12 steers weighing 253 kg received hGRF(1-29)NH2 in H2O at rates of 0, 3, 30 and 300 pmol.h-1.kg-1. Pumps were implanted s.c. on d 0 and removed at 1200 on d 7. Blood samples were drawn at 20-min intervals from 0800 to 1200 on d -1, 1, 3, 5, 7 and 9. Growth hormone levels were not altered by GRF treatment (P greater than .05). Solubility and volume limitations render hGRF(1-29)NH2 delivery via osmotic pumps problematical. Flow rate and duration of release of dimethyl sulfoxide (DMSO):H2) (1:1) from osmotic pumps incubated in vivo and in vitro were found to be consistent with manufacturer's specifications. Two hGRF(1-29) analogues, Ro23-7863 and 4SG-29, were dissolved in DMSO:H2O. In Exp. 2, six 222-kg steers had pumps implanted and blood samples were taken as in Exp. 1. Three steers received each analogue at a rate of 300 pmol.h-1.kg-1. Analogues had similar GH-releasing ability and GH levels differed (P less than 0.001) among days, being approximately fourfold higher on d 3, 5 and 7 than on d -1, 1 and 9. Residual analogue solutions retained full bioactivity after 7-d implantation, and in vitro biopotencies of Ro23-7863 and 4SG-29 were similar (Exp. 3). In Exp. 4, 15 wethers (means = 31.3 kg) received osmotic pumps delivering 0, 3, 15, 75 and 300 pmol.h-1.kg-1 Ro23-7863 in DMSO:H2O for 7 d. Lambs were bled at 0800 and 1400 from d -1 to 8. The latter two doses increased (P less than .01) mean GH levels 2.7- and 4.3-fold over those in control animals during the treatment period. Results demonstrate that increased GH secretion can be elicited in steers and wethers for 1 wk by continuous s.c. infusion of GRF analogues utilizing osmotic pumps.

  2. The Regulation and Function of Fibroblast Growth Factor 8 and Its Function during Gonadotropin-Releasing Hormone Neuron Development

    PubMed Central

    Chung, Wilson C. J.; Linscott, Megan L.; Rodriguez, Karla M.; Stewart, Courtney E.

    2016-01-01

    Over the last few years, numerous studies solidified the hypothesis that fibroblast growth factor (FGF) signaling regulates neuroendocrine progenitor cell proliferation, fate specification, and cell survival and, therefore, is critical for the regulation and maintenance of homeostasis of the body. One important example that underscores the involvement of FGF signaling during neuroendocrine cell development is gonadotropin-releasing hormone (GnRH) neuron ontogenesis. Indeed, transgenic mice with reduced olfactory placode (OP) Fgf8 expression do not have GnRH neurons. This observation indicates the requirement of FGF8 signaling for the emergence of the GnRH neuronal system in the embryonic OP, the putative birth place of GnRH neurons. Mammalian reproductive success depends on the presence of GnRH neurons to stimulate gonadotropin secretion from the anterior pituitary, which activates gonadal steroidogenesis and gametogenesis. Together, these observations are critical for understanding the function of GnRH neurons and their control of the hypothalamus–pituitary–gonadal (HPG) axis to maintain fertility. Taken together, these studies illustrate that GnRH neuron emergence and hence HPG function is vulnerable to genomic and molecular signals that abnormally modify Fgf8 expression in the developing mouse OP. In this short review, we focus on research that is aimed at unraveling how androgen, all-trans retinoic acid, and how epigenetic factors modify control mouse OP Fgf8 transcription in the context of GnRH neuronal development and mammalian reproductive success. PMID:27656162

  3. Neither bovine somatotropin nor growth hormone-releasing factor alters expression of thyroid hormone receptors in liver and mammary tissues.

    PubMed

    Capuco, A V; Binelli, M; Tucker, H A

    2011-10-01

    Physiological effects of thyroid hormones are mediated primarily by binding of triiodothyronine to specific nuclear receptors. Organ-specific changes in production of triiodothyronine from its prohormone, thyroxine, have been hypothesized to target the action of thyroid hormones on the mammary gland and play a role in mediating or augmenting a galactopoietic response to bovine somatotropin (bST). Additionally, tissue responsiveness to thyroid hormones may be altered by changes in the number or affinity of nuclear receptors for thyroid hormones. In the present study, effects of bST and bovine growth hormone-releasing factor (bGRF) on thyroid hormone receptors in liver and mammary gland were studied. Lactating Holstein cows received continuous infusions of bST or bGRF for 63 d or served as uninfused controls. Nuclei were isolated from harvested mammary and liver tissues and incubated with [(125)I]-triiodothyronine. Treatments did not alter the capacity or affinity of specific binding sites for triiodothyronine in liver or mammary nuclei. Evaluation of transcript abundance for thyroid hormone receptors showed that isoforms of thyroid hormone receptor or retinoid receptor (which may influence thyroid receptor action) expressed in the mammary gland were not altered by bST or bGRF treatment. Data do not support the hypothesis that administration of bST or bGRF alters sensitivity of mammary tissue by changing expression of thyroid hormone receptors.

  4. Superoxide dismutase abolishes the platelet-derived growth factor-induced release of prostaglandin E2 by blocking induction of nitric oxide synthase: role of superoxide.

    PubMed

    Kelner, M J; Uglik, S F

    1995-09-10

    The ability of platelet-derived growth factor (PDGF) to induce prostaglandin E2 (PGE2) release in fibroblasts is abolished when copper-zinc superoxide dismutase activity is increased by transfection of an expression vector. The effect is specific to copper-zinc superoxide dismutase as glutathione peroxidase-overexpressing NIH3T3 cells, again produced by transfection of an expression vector, retain the ability to release PGE2 in response to growth factor stimulation. The defect in PDGF-induced PGE2 release occurs prior to action of prostaglandin H synthase/cyclooxygenase as release of arachadonic acid (in response to PDGF) does not occur in the superoxide dismutase-overexpressing clones. The defect in PDGF-induced release of PGE2 in superoxide dismutase-overexpressing clones differs from the defect found in pEJ-ras-transformed clones. The parent cells, the glutathione peroxidase-expressing cells, and the superoxide dismutase-overexpressing cells all release PGE2 in response to exogenous nitric oxide, whereas the pEJ-ras-transformed cells do not. The glutathione peroxidase-expressing cells also retained the ability to release nitrite in response to PDGF, whereas the superoxide dismutase-expressing clones do not. PDGF stimulates nitric oxide synthase activity in NIH3T3 cells, but not in the superoxide dismutase-expressing clones. These results indicate that superoxide dismutase overexpression blocks the PDGF-induced release of PGE2 by blocking induction of nitric oxide synthase. This indicates that the increase of nitric oxide synthase induced by PDGF is mediated in part by production of superoxide. These findings link cellular oxygen radical homeostasis to three different classes of messenger molecules (growth factors, nitric oxide, and prostaglandins).

  5. Expression and release of the latent transforming growth factor beta binding protein by hepatocytes from rat liver.

    PubMed

    Roth, S; Schurek, J; Gressner, A M

    1997-06-01

    In very recent studies it was established that transforming growth factor beta (TGF-beta), likely to be the most relevant fibrogenic cytokine and regulator of cell proliferation, differentiation, and matrix metabolism, is expressed by hepatocytes (parenchymal cell [PC]) and secreted from cultured PC in a latent form incapable of receptor binding. The structural composition of the latent TGF-beta complex secreted by cultured PC is unknown. In some TGF-beta expressing cell types this cytokine is released as a large molecular weight complex containing in addition to the TGF-beta latency associated peptide (LAP) a disulfide bonded latent TGF-beta binding protein (LTBP), of which the existence and function in liver is hitherto unknown. This study is directed to the identification of LTBP expression in rat PC. Cells were isolated from rat liver with the collagenase method and analyzed for LTBP before and during culture under standard conditions using alkaline phosphatase anti-alkaline phosphatase (APAAP) immunostainings, metabolic labeling, messenger RNA (mRNA) detection (reverse-transcription polymerase chain reaction [RT-PCR]) and sequencing, and immunoblotting of gel chromatographically separated cell extracts and conditioned media, respectively. APAAP immunostainings applying a specific polyclonal LTBP-antiserum (ab 39) indicated expression of LTBP in PC of liver in situ and freshly isolated PC but a strong expression in cultured PC. Transcripts of LTBP-1 were detected by RT-PCR and confirmed by sequence analyses. Metabolic labeling of PC with [35S]-Met/Cys followed by immunoprecipitation of cell lysates with LTBP antiserum confirmed the synthesis of the high molecular mass complex of 250 kd containing LTBP with a molecular mass of 160 kd. Latent TGF-beta complexes, associated with LTBP related proteins, could be separated from both extracts and conditioned media of PC by gel filtration chromatography. They confirmed the release of the large latent TGF-beta complex

  6. Growth hormone-releasing peptide-biotin conjugate stimulates myocytes differentiation through insulin-like growth factor-1 and collagen type I

    PubMed Central

    Lim, Chae Jin; Jeon, Jung Eun; Jeong, Se Kyoo; Yoon, Seok Jeong; Kwon, Seon Deok; Lim, Jina; Park, Keedon; Kim, Dae Yong; Ahn, Jeong Keun; Kim, Bong-Woo

    2015-01-01

    Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition. [BMB Reports 2015; 48(9): 501-506] PMID:25644636

  7. Growth hormone-releasing peptide-biotin conjugate stimulates myocytes differentiation through insulin-like growth factor-1 and collagen type I.

    PubMed

    Lim, Chae Jin; Jeon, Jung Eun; Jeong, Se Kyoo; Yoon, Seok Jeong; Kwon, Seon Deok; Lim, Jina; Park, Keedon; Kim, Dae Yong; Ahn, Jeong Keun; Kim, Bong-Woo

    2015-09-01

    Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition.

  8. Genistein prevents calcium mobilization evoked by platelet-derived growth factor without affecting calcium release by cadmium or bradykinin

    SciTech Connect

    Rong-Ming Lyu; Barnes, S.; Smith, J.B. )

    1991-03-11

    Cadmium (Cd) strikingly increases ({sup 3}H)inositol trisphosphate and evokes a spike in cytosolic free Ca (Ca{sub i}) in human dermal fibroblasts as described previously. Cd apparently activates a membrane receptor by binding to a zinc site in its external domain. Two classes of receptors are known to induce inositol phosphate formation and release stored Ca: those that are coupled to phospholipase C via GTP-binding proteins, e.g., the bradykinin (BK) receptor; and those that are tyrosine kinases, e.g. the receptor for platelet-derived growth factor (PDGF). Cd, 100 nM BK, and 10 ng/ml PDGF increased Ca{sub i} from 142 {plus minus} 24 nM to 809 {plus minus} 36, 964 {plus minus} 74, and 401 {plus minus} 52 nM (n = 5), respectively. Cd and BK immediately increased Ca{sub i}, however, there was a lag between the addition of PDGF compared to 15 {plus minus} 1 sec for Cd and 9 {plus minus} 1 sec for BK (all n = 10). Genistein (40 {mu}M, 40 min), which selectively inhibits tyrosine kinases, had no significant effect on the Ca{sub i} spike evoked by Cd or BK. In the presence of genistein Cd and BK increased Ca{sub i} from 165 {plus minus} 14 nM to 726 {plus minus} 23 and 876 {plus minus} 31 nM (n = 4), respectively. In contrast to Cd and BK, PDGF only slightly increased Ca{sub i} in the presence of 40 {mu}M genistein. The concentration of genistein that inhibited the Ca{sub i} response to PDGF by 50% was 8 {mu}M. These findings suggest that the Cd triggers a G protein-coupled receptor rather than a tyrosine kinase.

  9. Fibroblast growth factor 8 signaling through fibroblast growth factor receptor 1 is required for the emergence of gonadotropin-releasing hormone neurons.

    PubMed

    Chung, Wilson C J; Moyle, Sarah S; Tsai, Pei-San

    2008-10-01

    GnRH neurons are essential for the onset and maintenance of reproduction. Mutations in both fibroblast growth factor receptor (Fgfr1) and Fgf8 have been shown to cause Kallmann syndrome, a disease characterized by hypogonadotropic hypogonadism and anosmia, indicating that FGF signaling is indispensable for the formation of a functional GnRH system. Presently it is unclear which stage of GnRH neuronal development is most impacted by FGF signaling deficiency. GnRH neurons express both FGFR1 and -3; thus, it is also unclear whether FGFR1 or FGFR3 contributes directly to GnRH system development. In this study, we examined the developing GnRH system in mice deficient in FGF8, FGFR1, or FGFR3 to elucidate the individual contribution of these FGF signaling components. Our results show that the early emergence of GnRH neurons from the embryonic olfactory placode requires FGF8 signaling, which is mediated through FGFR1, not FGFR3. These data provide compelling evidence that the developing GnRH system is exquisitely sensitive to reduced levels of FGF signaling. Furthermore, Kallmann syndrome stemming from FGF signaling deficiency may be due primarily to defects in early GnRH neuronal development prior to their migration into the forebrain.

  10. Transforming growth factor-beta 1 release from oligo(poly(ethylene glycol) fumarate) hydrogels in conditions that model the cartilage wound healing environment.

    PubMed

    Holland, Theresa A; Tessmar, Joerg K V; Tabata, Yasuhiko; Mikos, Antonios G

    2004-01-08

    This research demonstrates that controlled material degradation and transforming growth factor-beta1 (TGF-beta1) release can be achieved by encapsulation of TGF-beta1-loaded gelatin microparticles within the biodegradable polymer oligo(poly(ethylene glycol) fumarate) (OPF), so that these microparticles function as both a digestible porogen and a delivery vehicle. Release studies performed with non-encapsulated microparticles confirmed that at normal physiological pH, TGF-beta1 complexes with acidic gelatin, resulting in slow release rates. At pH 4.0, this complexation no longer persists, and TGF-beta1 release is enhanced. However, by encapsulating TGF-beta1-loaded microparticles in a network of OPF, release at either pH can be diffusionally controlled. For instance, after 28 days of incubation at pH 4.0, final cumulative release from non-encapsulated microparticles crosslinked in 10 and 40 mM glutaraldehyde (GA) was 75.4+/-1.6% and 76.6+/-1.1%, respectively. However, when either microparticle formulation was encapsulated in an OPF hydrogel (noted as OPF-10 mM and OPF-40 mM, respectively), these values were reduced to 44.7+/-14.6% and 47.4+/-4.7%. More interestingly, release studies, in conditions that model the expected collagenase concentration of injured cartilage, demonstrated that by altering the microparticle crosslinking extent and loading within OPF hydrogels, TGF-beta1 release, composite swelling, and polymer loss could be systematically altered. Composites encapsulating less crosslinked microparticles (OPF-10 mM) exhibited 100% release after only 18 days and were completely degraded by day 24 in collagenase-containing phosphate-buffered saline (PBS). Hydrogels encapsulating 40 mM GA microparticles did not exhibit 100% release or polymer loss until day 28. Hydrogels with no microparticle component demonstrated only 79.3+/-9.2% release and 89.2+/-3.4% polymer loss after 28 days in enzyme-containing PBS. Accordingly, these studies confirm that the rate of TGF

  11. Evaluation of the effect of calcium gluconate and bovine thrombin on the temporal release of transforming growth factor beta 1 and platelet-derived growth factor isoform BB from feline platelet concentrates

    PubMed Central

    2012-01-01

    Background There are not reported regarding the protocols for obtaining platelet concentrates (PC) in cats for medical purposes. The objectives of this study were: 1) to describe a manual method for producing two kinds of PC in cats (PC-A and PC-B), 2) to describe the cellular population of the PC, 3) to measure and compare the effect of calcium gluconate (CG) and bovine thrombin (BT) on the temporal release of transforming growth factor beta 1 (TGF-β1) and platelet-derived growth factor type BB (PDGF-BB) at 3 and 12 hours post-activation and 4) to establish correlations between the cellular population of both PCs and the concentration of growth factors (GF). Blood samples were taken from 16 cats for complete blood count, plasma collection and PC preparation. The PC were arbitrarily divided into two fractions, specifically, PC-A (lower fraction) and PC-B (upper fraction). Results The platelet counts were significantly different (P<0.05) between the PC and whole blood but not between the PC fractions. The TGF-β1 concentration efficiencies for PC-A and PC-B activated with CG were 42.86% and 46.54%, and activated with BT were 42.88% and 54.64%, respectively. The PDGF-BB concentration efficiencies for PC-A and PC-B activated with CG were 61.36% and 60.61%, and activated with BT were 65.64% and 72.12%, respectively. The temporal release of GFs showed no statistically significant difference (P>0.05) between the activating substances at the time or for any PC fraction. Conclusions Whatever the activation means, these preparations of cat PC provide significant concentrations of platelets and GFs for possible clinical or experimental use. PMID:23131192

  12. Cells transformed by murine herpesvirus 68 (MHV-68) release compounds with transforming and transformed phenotype suppressing activity resembling growth factors.

    PubMed

    Šupolíková, M; Staňová, A Vojs; Kúdelová, M; Marák, J; Zelník, V; Golais, F

    2015-12-01

    In this study, we investigated the medium of three cell lines transformed with murine herpesvirus 68 (MHV-68) in vitro and in vivo, 68/HDF, 68/NIH3T3, and S11E, for the presence of compounds resembling growth factors of some herpesviruses which have displayed transforming and transformed phenotype suppressing activity in normal and tumor cells. When any of spent medium was added to cell culture we observed the onset of transformed phenotype in baby hamster kidney cells (BHK-21) cells and transformed phenotype suppressing activity in tumor human epithelial cells (HeLa). In media tested, we have identified the presence of putative growth factor related to MHV-68 (MHGF-68). Its bivalent properties have been blocked entirely by antisera against MHV-68 and two monoclonal antibodies against glycoprotein B (gB) of MHV-68 suggesting viral origin of MHGF-68. The results of initial efforts to separate MHGF-68 on FPLC Sephadex G15 column in the absence of salts revealed the loss of its transforming activity but transformed phenotype suppressing activity retained. On the other hand, the use of methanol-water mobile phase on RP-HPLC C18 column allowed separation of MHGF-68 to two compounds. Both separated fractions, had only the transforming activity to normal cells. Further experiments exploring the nature and the structure of hitherto unknown MHGF-68 are now in the progress to characterize its molecular and biological properties.

  13. Extracellular Matrix (ECM) Multilayer Membrane as a Sustained Releasing Growth Factor Delivery System for rhTGF-β3 in Articular Cartilage Repair

    PubMed Central

    Park, Sang-Hyug; Kim, Moon Suk; Kim, Young Jick; Choi, Byung Hyune; Lee, Chun Tek; Park, So Ra; Min, Byoung-Hyun

    2016-01-01

    Recombinant human transforming growth factor beta-3 (rhTGF-β3) is a key regulator of chondrogenesis in stem cells and cartilage formation. We have developed a novel drug delivery system that continuously releases rhTGF-β3 using a multilayered extracellular matrix (ECM) membrane. We hypothesize that the sustained release of rhTGF-β3 could activate stem cells and result in enhanced repair of cartilage defects. The properties and efficacy of the ECM multilayer-based delivery system (EMLDS) are investigated using rhTGF-β3 as a candidate drug. The bioactivity of the released rhTGF-ß3 was evaluated through chondrogenic differentiation of mesenchymal stem cells (MSCs) using western blot and circular dichroism (CD) analyses in vitro. The cartilage reparability was evaluated through implanting EMLDS with endogenous and exogenous MSC in both in vivo and ex vivo models, respectively. In the results, the sustained release of rhTGF-ß3 was clearly observed over a prolonged period of time in vitro and the released rhTGF-β3 maintained its structural stability and biological activity. Successful cartilage repair was also demonstrated when rabbit MSCs were treated with rhTGF-β3-loaded EMLDS ((+) rhTGF-β3 EMLDS) in an in vivo model and when rabbit chondrocytes and MSCs were treated in ex vivo models. Therefore, the multilayer ECM membrane could be a useful drug delivery system for cartilage repair. PMID:27258120

  14. Growth hormone releasing factor (GRF) increases free arachidonate levels in the pituitary: a role for lipoxygenase products

    SciTech Connect

    Canonico, P.L.; Speciale, C.; Sortino, M.A.; Cronin, M.J.; MacLeod, R.M.; Scapagnini, U.

    1986-01-20

    GRF, a specific stimulator of GH release, increased in a concentration- and time-dependent manner pituitary (/sup 3/H)-arachidonate levels in vitro. This effect was antagonized by 100 nM somatostatin. Exogenous arachidonate also stimulated GH release in vitro. Quinacrine, a phospholipase A2 inhibitor, reduced both basal and GRF-stimulated free arachidonate levels as well as GH release. The cyclooxygenase inhibitor indomethacin was ineffective, while BW755c, which also inhibits the lipoxygenase pathway, produced a further increase in the levels of the fatty acid stimulated by GRF and potently reduced GH release. These results provide additional evidence for the involvement of arachidonate metabolism in the hormone-releasing effect of GRF at the somatotroph. 14 references, 1 figure, 2 tables.

  15. Botulinum toxin type A targets RhoB to inhibit lysophosphatidic acid-stimulated actin reorganization and acetylcholine release in nerve growth factor-treated PC12 cells.

    PubMed

    Ishida, Hiroshi; Zhang, Xieping; Erickson, Kelly; Ray, Prabhati

    2004-09-01

    Botulinum toxin type A (BoNT/A) produced by Clostridium botulinum inhibits Ca2+-dependent acetylcholine (ACh) release (neuroexocytosis) at peripheral neuromuscular junctions, sometimes causing neuromuscular paralysis. This inhibitory effect is attributed to its metalloprotease activity to cleave the 25-kDa synaptosomal-associated protein, which is essential for the exocytotic machinery. However, deletion of this protein does not result in a complete block of neuroexocytosis, suggesting that botulinum-mediated inhibition may occur via another mechanism. Rho GTPases, a class of small GTP-binding proteins (G proteins), control actin cytoskeletal organization, thereby regulating a variety of cellular functions in various cells, including neuronal cells. We have shown that the G protein activator lysophosphatidic acid (LPA) triggered actin reorganization followed by Ca2+-dependent ACh release in nerve growth factor-treated PC12 cells and that BoNT/A blocked both events through degradation of RhoB by the proteasome. Overexpression of wild-type RhoB caused actin reorganization and enhanced the release of ACh by LPA to overcome toxin's inhibitory effect on actin reorganization/exocytosis stimulated by LPA, whereas overexpression of a dominant negative RhoB inhibited ACh release, regardless of LPA and/or toxin treatment. Finally, a knockdown of the RhoB gene via sequence-specific, post-transcriptional gene silencing reduced RhoB expression in PC12 cells, resulting in total inhibition of both actin reorganization and ACh release induced by LPA. We conclude that the RhoB signaling pathway regulates ACh release via actin cytoskeletal reorganization and that botulinum toxin inhibits neuroexocytosis by targeting RhoB pathway.

  16. Sustained release of hepatocyte growth factor by cationic self-assembling peptide/heparin hybrid hydrogel improves β-cell survival and function through modulating inflammatory response

    PubMed Central

    Liu, Shuyun; Zhang, Lanlan; Cheng, Jingqiu; Lu, Yanrong; Liu, Jingping

    2016-01-01

    Inflammatory response is a major cause of grafts dysfunction in islet transplantation. Hepatocyte growth factor (HGF) had shown anti-inflammatory activity in multiple diseases. In this study, we aim to deliver HGF by self-assembling peptide/heparin (SAP/Hep) hybrid gel to protect β-cell from inflammatory injury. The morphological and slow release properties of SAPs were analyzed. Rat INS-1 β-cell line was treated with tumor necrosis factor α in vitro and transplanted into rat kidney capsule in vivo, and the viability, apoptosis, function, and inflammation of β-cells were evaluated. Cationic KLD1R and KLD2R self-assembled to nanofiber hydrogel, which showed higher binding affinity for Hep and HGF because of electrostatic interaction. Slow release of HGF from cationic SAP/Hep gel is a two-step mechanism involving binding affinity with Hep and molecular diffusion. In vitro and in vivo results showed that HGF-loaded KLD2R/Hep gel promoted β-cell survival and insulin secretion, and inhibited cell apoptosis, cytokine release, T-cell infiltration, and activation of NFκB/p38 MAPK pathways in β-cells. This study suggested that SAP/Hep gel is a promising carrier for local delivery of bioactive proteins in islet transplantation. PMID:27729786

  17. In vitro and in vivo evaluation of a novel collagen/cellulose nanocrystals scaffold for achieving the sustained release of basic fibroblast growth factor.

    PubMed

    Li, Weichang; Lan, Yong; Guo, Rui; Zhang, Yi; Xue, Wei; Zhang, Yuanming

    2015-01-01

    Tissue-engineered dermis is thought to be the best treatment for skin defects; however, slow vascularization of these biomaterial scaffolds limits their clinical application. Exogenous administration of angiogenic growth factors is highly desirable for tissue regeneration. In this study, biodegradable gelatin microspheres (GMs) containing basic fibroblast growth factor (bFGF) were fabricated and incorporated into a porous collagen/cellulose nanocrystals (CNCs) scaffold, as a platform for long-term release and consequent angiogenic boosting. The physicochemical properties of these scaffolds were examined and the in vitro release pattern of bFGF from scaffolds was measured by ELISA. Collagen/CNCs scaffolds with and without bFGF-GMs were incubated with human umbilical vein endothelial cells for 1 week, results showed that the scaffolds with bFGF-GMs significantly augmented cell proliferation. Then, four different groups of scaffolds were implanted subcutaneously into Sprague-Dawley rats to study angiogenesis in vivo via macroscopic observation, and hematoxylin and eosin and immunohistochemical staining. The results suggested that the collagen/CNCs/bFGF-GMs scaffolds had a significantly higher number of newly formed and mature blood vessels, and the fastest degradation rate. This study demonstrated that collagen/CNCs/bFGF-GMs scaffolds have great potential in skin tissue engineering.

  18. Novel epidermal growth factor receptor pathway mediates release of human β-defensin 3 from Helicobacter pylori-infected gastric epithelial cells.

    PubMed

    Muhammad, Jibran S; Zaidi, Syed F; Zhou, Yue; Sakurai, Hiroaki; Sugiyama, Toshiro

    2016-04-01

    Persistent Helicobacter pylori (H. pylori) infection in hostile gastric mucosa can result in gastric diseases. Helicobacter pylori induces to express antimicrobial peptides from gastric epithelial cells, especially human β-defensin 3 (hBD3), as an innate immune response, and this expression of hBD3 is mediated by epidermal growth factor receptor (EGFR) activation. In this study, we found that phosphorylation of a serine residue of EGFR via transforming growth factor β-activated kinase-1 (TAK1), and subsequent p38α activation is essential for H. pylori-induced hBD3 release from gastric epithelial cells. We showed that this pathway was dependent on H. pylori type IV secretion system and was independent of H. pylori-derived CagA or peptidoglycan. H. pylori infection induced phosphorylation of serine residue of EGFR, and this phosphorylation was followed by internalization of EGFR; consequently, hBD3 was released at an early phase of the infection. In the presence of TAK1 or p38α inhibitors, synthesis of hBD3 was completely inhibited. Similar results were observed in EGFR-, TAK1- or p38α-knockdown cells. However, NOD1 knockdown in gastric epithelial cells did not inhibit hBD3 induction. Our study has firstly demonstrated that this novel EGFR activating pathway functioned to induce hBD3 at an early phase of H. pylori infection.

  19. Effects of transforming growth factor beta1 released from biodegradable polymer microparticles on marrow stromal osteoblasts cultured on poly(propylene fumarate) substrates.

    PubMed

    Peter, S J; Lu, L; Kim, D J; Stamatas, G N; Miller, M J; Yaszemski, M J; Mikos, A G

    2000-06-05

    Recombinant human transforming growth factor beta1 (TGF-beta1) was incorporated into microparticles of blends of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) to create a delivery vehicle for the growth factor. The entrapment efficiency of TGF-beta1 in the microparticles containing 5% PEG was 40.3 +/- 1.2% for a TGF-beta1 loading density of 6.0 ng/1 mg of microparticles. For the same loading, 17.9 +/- 0.6 and 32.1 +/- 2.5% of the loaded TGF-beta1 was released after 1 and 8 days, respectively, followed by a plateau for the remaining 3 weeks. Rat marrow stromal cells showed a dose response to TGF-beta1 released from the microparticles similar to that of added TGF-beta1, indicating the activity of TGF-beta1 was retained during microparticle fabrication and after TGF-beta1 release. An optimal TGF-beta1 dosage of 1.0 ng/mL was determined through a 3-day dose response study for maximal alkaline phosphatase (ALP) activity. The TGF-beta1 released from the microparticles loaded with 6.0 ng TGF-beta1/1 mg of microparticles for the optimal dosage of TGF-beta1 enhanced the proliferation and osteoblastic differentiation of marrow stromal cells cultured on poly(propylene fumarate) substrates. The cells showed significantly increased total cell number, ALP activity, and osteocalcin production with values reaching 138,700 +/- 3300 cells/cm(2), 22.8 +/- 1.5 x 10(-7) micromol/min/cell, and 15.9 +/- 1.5 x 10(-6) ng/cell, respectively, after 21 days as compared to cells cultured under control conditions without TGF-beta1. These results suggest that controlled release of TGF-beta1 from the PLGA/PEG blend microparticles may find applications in modulating cellular response during bone healing at a skeletal defect site.

  20. Role of transiently altered sarcolemmal membrane permeability and basic fibroblast growth factor release in the hypertrophic response of adult rat ventricular myocytes to increased mechanical activity in vitro.

    PubMed Central

    Kaye, D; Pimental, D; Prasad, S; Mäki, T; Berger, H J; McNeil, P L; Smith, T W; Kelly, R A

    1996-01-01

    One of the trophic factors that has been implicated in initiating or facilitating growth in response to increased mechanical stress in several tissues and cell types is basic fibroblast growth factor (bFGF; FGF-2). Although mammalian cardiac muscle cells express bFGF, it is not known whether it plays a role in mediating cardiac adaptation to increased load, nor how release of the cytosolic 18-kD isoform of bFGF would be regulated in response to increased mechanical stress. To test the hypothesis that increased mechanical activity induces transient alterations in sarcolemmal permeability that allow cytosolic bFGF to be released and subsequently to act as an autocrine and paracrine growth stimulus, we examined primary isolates of adult rat ventricular myocytes maintained in serum-free, defined medium that were continually paced at 3 Hz for up to 5 d. Paced myocytes, but not nonpaced control cells, exhibited a "hypertrophic" response, which was characterized by increases in the rate of phenylalanine incorporation, total cellular protein content, and cell size. These changes could be mimicked in control cells by exogenous recombinant bFGF and could be blocked in continually paced cells by a specific neutralizing anti-bFGF antibody. In addition, medium conditioned by continually paced myocytes contained significantly more bFGF measured by ELISA and more mitogenic activity for 3T3 cells, activity that could be reduced by a neutralizing anti-bFGF antibody. The hypothesis that transient membrane disruptions sufficient to allow release of cytosolic bFGF occur in paced myocytes was examined by monitoring the rate of uptake into myocytes from the medium of 10-kD dextran linked to fluorescein. Paced myocytes exhibited a significantly higher rate of fluoresceinlabeled dextran uptake. These data are consistent with the hypothesis that nonlethal, transient alterations in sarcolemmal membrane permeability with release of cytosolic bFGF is one mechanism by which increased

  1. Erythropoietin inhibits osmotic swelling of retinal glial cells by Janus kinase- and extracellular signal-regulated kinases1/2-mediated release of vascular endothelial growth factor.

    PubMed

    Krügel, K; Wurm, A; Linnertz, R; Pannicke, T; Wiedemann, P; Reichenbach, A; Bringmann, A

    2010-02-17

    The volume homeostasis of retinal glial cells is mediated by an autocrine purinergic mechanism of ion channel opening which is activated in response to a decrease in the extracellular osmolarity. Here, we show that erythropoietin (EPO) prevents the osmotic swelling of glial somata in retinal slices and of isolated glial cells from control and diabetic rats, with a half-maximal effect at approximately 0.01 nM. The downstream signaling evoked by EPO includes a release of vascular endothelial growth factor from the cells which was blocked by Janus kinase and extracellular signal-regulated kinases (ERK)1/2 inhibitors. Transactivation of kinase insert domain-containing receptor/fms-like tyrosine kinase 1 (KDR/flk-1) evokes a calcium-dependent, exocytotic release of glutamate, followed by activation of group I/II metabotropic glutamate receptors which results in calcium-independent release of ATP and adenosine from the cells. The final step in this cascade is the activation of adenosine A(1) receptors which results in protein kinase A- and phosphoinositide 3-kinase-mediated opening of potassium and chloride channels. EPO receptor protein was immunohistochemically localized to the inner retina and photoreceptor inner segments. In isolated glial cells, EPO receptor protein is selectively localized to fibers which traverse the inner nuclear layer in situ. Inhibition of glial swelling might contribute to the neuroprotective action of EPO in the retina under pathological conditions.

  2. Experiment K-7-22: Growth Hormone Regulation Synthesis and Secretion in Microgravity. Part 2; Hypothalamic Growth Hormone-Releasing Factor, Somatostatin Immunoreactivity, and Messenger RNA Levels in Microgravity

    NASA Technical Reports Server (NTRS)

    Sawchenko, P. E.; Arias, C.; Krasnov, I.; Grindeland, R. E.; Vale, W.

    1994-01-01

    Immunohistochemical analyses of hypothalamic hormones carried out on tissue from rats flown on an earlier flight (Cosmos 1887) suggested preferential effects on hypophysiotropic principles involved in the regulation of growth hormone secretion and synthesis. We found that staining in the median eminence for peptides that provide both stimulatory (growth hormone-releasing factor, or GRF) and inhibitory (somatostatin, SS) influences on growth hormone secretion were depressed in flight animals relative to synchronous controls, while staining for other neuroendocrine peptides, cortocotropin-releasing factor and arginine vasopressin, were similar in these two groups. While this suggests some selective impact of weightlessness on the two principal central nervous system regulators of growth hormone dynamics, the fact that both GRF- and SS-immunoreactivity (IR) appeared affected in the same direction is somewhat problematic, and makes tentative any intimation that effects on CNS control mechanisms may be etiologically significant contributors to the sequelae of reduced growth hormone secretion seen in prolonged space flight. To provide an additional, and more penetrating, analysis we attempted in hypothalamic material harvested from animals flown on Cosmos 2044 to complement immunohistochemical analyses of GRF and SS staining with quantitative, in situ assessments of messenger RNAs encoding the precursors for both these hormones.

  3. Factors affecting bone growth.

    PubMed

    Gkiatas, Ioannis; Lykissas, Marios; Kostas-Agnantis, Ioannis; Korompilias, Anastasios; Batistatou, Anna; Beris, Alexandros

    2015-02-01

    Bone growth and development are products of the complex interactions of genetic and environmental factors. Longitudinal bone growth depends on the growth plate. The growth plate has 5 different zones-each with a different functional role-and is the final target organ for longitudinal growth. Bone length is affected by several systemic, local, and mechanical factors. All these regulation systems control the final length of bones in a complicated way. Despite its significance to bone stability, bone growth in width has not been studied as extensively as longitudinal bone growth. Bone growth in width is also controlled by genetic factors, but mechanical loading regulates periosteal apposition. In this article, we review the most recent data regarding bone growth from the embryonic age and analyze the factors that control bone growth. An understanding of this complex system is important in identifying metabolic and developmental bone diseases and fracture risk.

  4. Regeneration of anterior cruciate ligament by biodegradable scaffold combined with local controlled release of basic fibroblast growth factor and collagen wrapping.

    PubMed

    Kimura, Yuta; Hokugo, Akishige; Takamoto, Tomoaki; Tabata, Yasuhiko; Kurosawa, Hisashi

    2008-03-01

    The objective of this study was to increase the therapeutic efficacy of anterior cruciate ligament (ACL) surgery using an artificial ligament material developed through a combination of tissue engineering technologies. A poly-L-lactic acid (PLLA) scaffold of plain-woven braid was incorporated with a gelatin hydrogel for controlled release of basic fibroblast growth factor (bFGF) and wrapped with a collagen membrane to allow space for ligament regeneration. For the ACL reconstruction surgery, the PLLA braid scaffold combined with the gelatin hydrogel incorporating bFGF and the collagen wrapping was applied to a tunnel prepared in the femur and tibia of rabbits. The hydrogel was placed in the bone, whereas the portion of the braid inside the joint cavity was wrapped with the membrane. As controls, the PLLA scaffold was applied with the hydrogel or the membrane, or without either material. Bone regeneration in the tunnel and ACL tissue regeneration in the joint cavity were histologically evaluated, and the mechanical strength and collagen content of the regenerated ACL were assessed. When the PLLA scaffold was integrated with both the hydrogel and the membrane, bone and ACL tissues were regenerated in the corresponding sites, in marked contrast to the control groups. Combination of bFGF-controlled release resulted in enhanced mechanical strength of the regenerated ACL tissue. In the joint cavity, it is possible that the local bFGF release inside the membrane enhanced the cell migration and collagen production, and that the surrounding PLLA scaffold results in the biological regeneration of ligament-like tissue. Additionally, significant bone regeneration around the scaffold was observed in the bone tunnel. It is therefore possible that the local controlled release of bFGF near the PLLA braid induced both osseointegration and intrascaffold cell migration in the bone tunnel and joint cavity, respectively, resulting in an overall increase in the mechanical strength of

  5. BET Bromodomains Regulate Transforming Growth Factor-β-induced Proliferation and Cytokine Release in Asthmatic Airway Smooth Muscle*

    PubMed Central

    Perry, Mark M.; Durham, Andrew L.; Austin, Philip J.; Adcock, Ian M.; Chung, Kian Fan

    2015-01-01

    Airway smooth muscle (ASM) mass is increased in asthma, and ASM cells from patients with asthma are hyperproliferative and release more IL-6 and CXCL8. The BET (bromo- and extra-terminal) family of proteins (Brd2, Brd3, and Brd4) govern the assembly of histone acetylation-dependent chromatin complexes. We have examined whether they modulate proliferation and cytokine expression in asthmatic ASM cells by studying the effect of BET bromodomain mimics JQ1/SGCBD01 and I-BET762. ASM cells from healthy individuals and nonsevere and severe asthmatics were pretreated with JQ1/SGCBD01 and I-BET762 prior to stimulation with FCS and TGF-β. Proliferation was measured by BrdU incorporation. IL-6 and CXCL8 release was measured by ELISA, and mRNA expression was measured by quantitative RT-PCR. ChIP using a specific anti-Brd4 antibody and PCR primers directed against the transcriptional start site of IL-6 and CXCL8 gene promoters was performed. Neither JQ1/SGCBD01 nor I-BET762 had any effect on ASM cell viability. JQ1/SGCBD01 and I-BET762 inhibited FCS+TGF-β-induced ASM cell proliferation and IL-6 and CXCL8 release in healthy individuals (≥ 30 nm) and in nonsevere and severe asthma patients (≥100 nm), with the latter requiring higher concentrations of these mimics. JQ1/SGCBD01 reduced Brd4 binding to IL8 and IL6 promoters induced by FCS+TGF-β. Mimics of BET bromodomains inhibit aberrant ASM cell proliferation and inflammation with lesser efficiency in those from asthmatic patients. They may be effective in reducing airway remodeling in asthma. PMID:25697361

  6. Temporal growth factor release from platelet-rich plasma, trehalose lyophilized platelets, and bone marrow aspirate and their effect on tendon and ligament gene expression.

    PubMed

    McCarrel, Taralyn; Fortier, Lisa

    2009-08-01

    Platelet-rich plasma (PRP) has generated substantial interest for tendon and ligament regeneration because of the high concentrations of growth factors in platelet alpha-granules. This study compared the temporal release of growth factors from bone marrow aspirate (BMA), PRP, and lyophilized platelet product (PP), and measured their effects on tendon and ligament gene expression. Blood and BMA were collected and processed to yield PRP and plasma. Flexor digitorum superficialis tendon (FDS) and suspensory ligament (SL) explants were cultured in 10% plasma in DMEM (control), BMA, PRP, or PP. TGF-beta1 and PDGF-BB concentrations were determined at 0, 24, and 96 h of culture using ELISA. Quantitative RT-PCR for collagen types I and III (COL1A1, COL3A1), cartilage oligomeric matrix protein (COMP), decorin, and matrix metalloproteinases-3 and 13 (MMP-3, MMP-13) was performed. TGF-beta1 and PDGF-BB concentrations were highest in PRP and PP. Growth factor quantity was unchanged in BMA, increased in PRP, and decreased in PP over 4 days. TGF-beta1 and platelet concentrations were positively correlated. Lyophilized PP and PRP resulted in increased COL1A1:COL3A1 ratio, increased COMP, and decreased MMP-13 expression. BMA resulted in decreased COMP and increased MMP-3 and MMP-13 gene expression. Platelet concentration was positively correlated with COL1A1, ratio of COL1A1:COL3A1, and COMP, and negatively correlated with COL3A1, MMP-13, and MMP-3. White blood cell concentration was positively correlated with COL3A1, MMP3, and MMP13, and negatively correlated with a ratio of COL1A1:COL3A1, COMP, and decorin. These findings support further in vivo investigation of PRP and PP for treatment of tendonitis and desmitis.

  7. Engineered Cartilage via Self-Assembled hMSC Sheets with Incorporated Biodegradable Gelatin Microspheres Releasing Transforming Growth Factor-β1

    PubMed Central

    Solorio, Loran D.; Vieregge, Eran L.; Dhami, Chirag D.; Dang, Phuong N.; Alsberg, Eben

    2011-01-01

    Self-assembling cell sheets have shown great potential for use in cartilage tissue engineering applications, as they provide an advantageous environment for the chondrogenic induction of human mesenchymal stem cells (hMSCs). We have engineered a system of self-assembled, microsphere-incorporated hMSC sheets capable of forming cartilage in the presence of exogenous transforming growth factor β1 (TGF-β1) or with TGF-β1 released from incorporated microspheres. Gelatin microspheres with two different degrees of crosslinking were used to enable different cell-mediated microsphere degradation rates. Biochemical assays, histological and immunohistochemical analyses, and biomechanical testing were performed to determine biochemical composition, structure, and equilibrium modulus in unconfined compression after 3 weeks of culture. The inclusion of microspheres with or without loaded TGF-β1 significantly increased sheet thickness and compressive equilibrium modulus, and enabled more uniform matrix deposition by comparison to control sheets without microspheres. Sheets incorporated with fast-degrading microspheres containing TGF-β1 produced significantly more GAG and GAG per DNA than all other groups tested and stained more intensely for type II collagen. These findings demonstrate improved cartilage formation in microsphere-incorporated cell sheets, and describe a tailorable system for the chondrogenic induction of hMSCs without necessitating culture in growth factor-containing medium. PMID:22100386

  8. Transforming growth factor-beta1 incorporation in an alpha-tricalcium phosphate/dicalcium phosphate dihydrate/tetracalcium phosphate monoxide cement: release characteristics and physicochemical properties.

    PubMed

    Blom, E J; Klein-Nulend, J; Wolke, J G C; Kurashina, K; van Waas, M A J; Burger, E H

    2002-02-01

    The osteoconductive properties of calcium phosphate cements (CPCs) may be improved by the addition of growth factors, such as recombinant human transforming growth factor-beta1 (rhTGF-beta1). Previously we have shown that rhTGF-beta1 was released from cement enriched with rhTGF-beta1 and subsequently stimulated the differentiation of pre-osteoblastic cells from adult rat long bones. It is unknown whether the addition of rhTGF-beta1 changes the material properties of this alpha-tricalcium-phosphate (alpha-TCP)/tetracalcium-phosphate-monoxide (TeCP)/dicalcium-phosphate-dihydrate (DCPD) cement, and what the characteristics of the release of rhTGF-beta1 from this CPC are. Therefore, in the present study we determined the release of rhTGF-beta1 from cement pellets in vitro. The possible intervening effects of the CPC modification for intermixing rhTGF-beta1 on physicochemical properties were studied by assessing the compressive strength and setting time, as well as crystallinity, calcium to phosphorus ratio, porosity and microscopic structure. Most of the previously incorporated rhTGF-beta1 in the cement pellets was released within the first 48 h. For all concentrations of rhTGF-beta1 intermixed (100 ng-2.5 mg/g CPC), approximately 0.5% of the amount of rhTGF-beta1 incorporated initially was released in the first 2 h, increasing to 1.0% after 48 h. The release of rhTGF-beta1 continued hereafter at a rate of about 0.1% up to 1 week, after which no additional release was found. The initial setting time, nor the final setting time was changed in control cement without rhTGF-beta1 (standard CPC) or in cement modified for rhTGF-beta1 (modified CPC) at 20 degrees C and 37 degrees C. Setting times were more than six times decreased at 37 degrees C compared to 20 degrees C. The compressive strength was initially low for both standard CPC and modified CPC, after which it increased between 24 h and 8 weeks. The compressive strength for the modified CPC was significantly higher

  9. Infection of murine macrophages with Toxoplasma gondii is associated with release of transforming growth factor beta and downregulation of expression of tumor necrosis factor receptors.

    PubMed Central

    Bermudez, L E; Covaro, G; Remington, J

    1993-01-01

    Toxoplasma gondii is capable of invading and multiplying within murine peritoneal macrophages. Previous studies have shown that treatment of macrophage monolayers with recombinant gamma interferon but not tumor necrosis factor (TNF) is associated with intracellular killing of T. gondii by macrophages. Furthermore, infection of macrophages with T. gondii prevents their stimulation for mycobactericidal activity by TNF. Since transforming growth factor beta (TGF-beta) is known to suppress a number of functions in macrophages, we investigated the influence of infection with T. gondii on macrophage TNF receptors and on production of TGF-beta. Infection with T. gondii was associated with increased production of TGF-beta and downregulation of TNF receptors. This effect was observed early after infection and was partially inhibited by anti-TGF-beta 1 antibody. PMID:8406801

  10. The effect of continuous release of recombinant human epidermal growth factor (rh-EGF) in chitosan film on full thickness excisional porcine wounds.

    PubMed

    Hong, Joon Pio; Kim, Yeun Wha; Lee, Sang Kil; Kim, Sun Hee; Min, Kyung Hyun

    2008-10-01

    The purpose of this article is to evaluate the effect of continuously released recombinant human epidermal growth factor (rh-EGF) in chitosan film in full thickness porcine wounds. A total of 10 domestic pigs (Yorkshire species) weighing 18 to 22 kg between the ages of 50 to 60 days were used. The wounds were divided into 3 groups and treated selectively with rh-EGF in chitosan film (EGF 20 ug/wound/d), chitosan film without rh-EGF, or remained as the control group. One hundred percent healing time was observed, and hematoxylin and eosin and Anti Ki-67 antibody immunohistochemical staining were performed. The 100% healing time and Anti Ki-67 antibody immunohistochemical staining showed statistical significance of the rh-EGF chitosan film-treated group against the control group (P < 0.05). But it did not reveal any statistical significance over the chitosan film-treated group. In this preliminary study, although continuous release of rh-EGF in chitosan film accelerates epithelialization, the benefit of the combination of rh-EGF in chitosan cannot be determined over the use of chitosan alone. Further analysis using complex wound models such as diabetes or infection, which may have different pathology in healing, will be needed to evaluate the potential benefit/synergistic effectiveness.

  11. 1alpha,25(OH)2D3 is an autocrine regulator of extracellular matrix turnover and growth factor release via ERp60 activated matrix vesicle metalloproteinases.

    PubMed

    Boyan, Barbara D; Wong, Kevin L; Fang, Mimi; Schwartz, Zvi

    2007-03-01

    Growth plate chondrocytes produce proteoglycan-rich type II collagen extracellular matrix (ECM). During cell maturation and hypertrophy, ECM is reorganized via a process regulated by 1alpha,25(OH)(2)D(3) and involving matrix metalloproteinases (MMPs), including MMP-3 and MMP-2. 1alpha,25(OH)(2)D(3) regulates MMP incorporation into matrix vesicles (MVs), where they are stored until released. Like plasma membranes (PM), MVs contain the 1alpha,25(OH)(2)D(3)-binding protein ERp60, phospholipase A(2) (PLA(2)), and caveolin-1, but appear to lack nuclear Vitamin D receptors (VDRs). Chondrocytes produce 1alpha,25(OH)(2)D(3) (10(-8)M), which binds ERp60, activating PLA(2), and resulting lysophospholipids lead to MV membrane disorganization, releasing active MMPs. MV MMP-3 activates TGF-beta1 stored in the ECM as large latent TGF-beta1 complexes, consisting of latent TGF-beta1 binding protein, latency associated peptide, and latent TGF-beta1. Others have shown that MMP-2 specifically activates TGF-beta2. TGF-beta1 regulates 1alpha,25(OH)(2)D(3)-production, providing a mechanism for local control of growth factor activation. 1alpha,25(OH)(2)D(3) activates PKCalpha in the PM via ERp60-signaling through PLA(2), lysophospholipid production, and PLCbeta. It also regulates distribution of phospholipids and PKC isoforms between MVs and PMs, enriching the MVs in PKCzeta. Direct activation of MMP-3 in MVs requires ERp60. However, when MVs are treated with 1alpha,25(OH)(2)D(3), PKCzeta activity is decreased and PKCalpha is unaffected, suggesting a more complex feedback mechanism, potentially involving MV lipid signaling.

  12. Recommended for release on recognizance: factors affecting pretrial release recommendations.

    PubMed

    Petee, T A

    1994-06-01

    Researchers have acknowledged the influence of pretrial release agencies in judicial decision making regarding bail; however, few researchers have focused on the process used by the pretrial release agencies to make bail-bond recommendations. In this study I sought to establish which factors were most salient in making the decision to recommend a defendant for release on recognizance. I found that both officially sanctioned release criteria and "extralegal" variables were predictive of this decision.

  13. The Effect of Lupinus albus on Growth Performance, Body Composition and Satiety Hormones of Male Pigs Immunized against Gonadotrophin Releasing Factor

    PubMed Central

    Moore, Karen; Mullan, Bruce; Kim, Jae Cheol; Dunshea, Frank

    2017-01-01

    Simple Summary Pigs immunized against gonadotrophin releasing factor (immunocastrates; IC males) have an increased feed intake, growth rate, back fat and fat deposition compared to entire males. A previous experiment found that Lupinus albus L. (albus lupins) has the potential to reduce feed intake and fat deposition in IC males. The current experiment aimed to develop a dietary management strategy using albus lupins for either 14 or 28 days pre-slaughter to reduce the increase in feed intake and subsequent increase in carcass fatness in IC males. Abstract Two hundred and ninety four pigs were used with the aim to develop a dietary management strategy using Lupinus albus L. (albus lupins) to reduce the increase in feed intake and subsequent increase in carcass fatness in pigs immunized against gonadotrophin releasing factor (immunocastrates; IC males) and entire male pigs in the late finishing stage. From day (d) 0 to 28, IC males fed the control diet grew faster (p = 0.009) than entire males fed the control diet but there was no difference in growth rate between sexes for pigs fed albus lupins for 14 days pre-slaughter (Albus 14) or pigs fed albus lupins for 28 days pre-slaughter (Albus 28). From d 15 to 28, IC males receiving the Albus 14 diet grew more slowly (p < 0.001) than entire males receiving the Albus 14 diet. From d 15 to 28 (p < 0.001), IC males fed the control diet ate more feed than entire males fed the control diet, although there was no difference between sexes in feed intake of the Albus 14 and Albus 28 diet. Immunocastrates had a lower backfat when fed either Albus 14 or Albus 28 compared to the control diet, although there was no difference between diets for entire males. There was also a trend for pigs on the Albus 14 and Albus 28 diets to have a higher lean deposition (p = 0.055) and a lower fat deposition (p = 0.056) compared to the pigs on the control diet. Pigs fed the Albus 28 diet had a lower plasma ghrelin concentration compared to pigs

  14. Time- and dose-dependent responses of brain histamine to intracerebroventricular and intraperitoneal administrations of growth hormone-releasing factor (GRF1-44).

    PubMed

    Cacabelos, R; Yamatodani, A; Fukui, H; Niigawa, H; Miyake, A; Watanabe, T; Nishimura, T; Wada, H

    1987-04-01

    Changes in the level of histamine (HA) in rat brain induced by intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administrations of growth hormone-releasing factor (GRF1-44) were studied. HA was determined by high-performance liquid chromatography (HPLC) in the anterior hypothalamic region, posterior hypothalamic region, median eminence, adenohypophysis, neurohypophysis, hippocampus and prefrontal cortex. GRF1-44 (1-10 micrograms, i.c.v.) induced significant time- and dose-dependent increases in the concentration of HA in the hypothalamo-hypophyseal system and time-dependent decrease of HA in the hippocampus. In contrast, after i.p. administration of GRF1-44 (10 micrograms) the level of HA in the hypothalamus tended to decrease but the total amount of H-1 receptors in the hypothalamo-hypophyseal system did not change. Circadian variations in the GRF-induced HA and growth hormone responses were also observed, responses being lower in the evening than in the morning. It is concluded that GRF interacts with HA at the central level to optimize the function of the somatotropinergic system.

  15. Ghrelin and obestatin modulate growth hormone-releasing hormone release and synaptic inputs onto growth hormone-releasing hormone neurons.

    PubMed

    Feng, Dan D; Yang, Seung-Kwon; Loudes, Catherine; Simon, Axelle; Al-Sarraf, Tamara; Culler, Michael; Alvear-Perez, Rodrigo; Llorens-Cortes, Catherine; Chen, Chen; Epelbaum, Jacques; Gardette, Robert

    2011-09-01

    Ghrelin, a natural ligand of the growth hormone secretagogue receptor (GHS-R), is synthesized in the stomach but may also be expressed in lesser quantity in the hypothalamus where the GHS-R is located on growth hormone-releasing hormone (GHRH) neurons. Obestatin, a peptide derived from the same precursor as ghrelin, is able to antagonize the ghrelin-induced increase of growth hormone (GH) secretion in vivo but not from pituitary explants in vitro. Thus, the blockade of ghrelin-induced GH release by obestatin could be mediated at the hypothalamic level by the neuronal network that controls pituitary GH secretion. Ghrelin increased GHRH and decreased somatostatin (somatotropin-releasing inhibitory factor) release from hypothalamic explants, whereas obestatin only reduced the ghrelin-induced increase of GHRH release, thus indicating that the effect of ghrelin and obestatin is targeted to GHRH neurons. Patch-clamp recordings on mouse GHRH-enhanced green fluorescent protein neurons indicated that ghrelin and obestatin had no significant effects on glutamatergic synaptic transmission. Ghrelin decreased GABAergic synaptic transmission in 44% of the recorded neurons, an effect blocked in the presence of the GHS-R antagonist BIM28163, and stimulated the firing rate of 78% of GHRH neurons. Obestatin blocked the effects of ghrelin by acting on a receptor different from the GHS-R. These data suggest that: (i) ghrelin increases GHRH neuron excitability by increasing their action potential firing rate and decreasing the strength of GABA inhibitory inputs, thereby leading to an enhanced GHRH release; and (ii) obestatin counteracts ghrelin actions. Such interactions on GHRH neurons probably participate in the control of GH secretion.

  16. Sustained dual release of placental growth factor-2 and bone morphogenic protein-2 from heparin-based nanocomplexes for direct osteogenesis

    PubMed Central

    Liu, Yun; Deng, Li-Zhi; Sun, Hai-Peng; Xu, Jia-Yun; Li, Yi-Ming; Xie, Xin; Zhang, Li-Ming; Deng, Fei-Long

    2016-01-01

    Objective To compare the direct osteogenic effect between placental growth factor-2 (PlGF-2) and bone morphogenic protein-2 (BMP-2). Methods Three groups of PlGF-2/BMP-2-loaded heparin–N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) nanocomplexes were prepared: those with 0.5 μg PlGF-2; with 1.0 μg BMP-2; and with 0.5 μg PlGF-2 combined with 1.0 μg BMP-2. The loading efficiencies and release profiles of these growth factors (GFs) in this nanocomplex system were quantified using enzyme-linked immunosorbent assay, their biological activities were evaluated using cell counting kit-8, cell morphology, and cell number counting assays, and their osteogenic activities were quantified using alkaline phosphatase and Alizarin Red S staining assays. Results The loading efficiencies were more than 99% for the nanocomplexes loaded with just PlGF-2 and for those loaded with both PlGF-2 and BMP-2. For the nanocomplex loaded with just BMP-2, the loading efficiency was more than 97%. About 83%–84% of PlGF-2 and 89%–91% of BMP-2 were stably retained on the nanocomplexes for at least 21 days. In in vitro biological assays, PlGF-2 exhibited osteogenic effects comparable to those of BMP-2 despite its dose in the experiments being lower than that of BMP-2. Moreover, the results implied that heparin-based nanocomplexes encapsulating two GFs have enhanced potential in the enhancement of osteoblast function. Conclusion PlGF-2-loaded heparin–HTCC nanocomplexes may constitute a promising system for bone regeneration. Moreover, the dual delivery of PlGF-2 and BMP-2 appears to have greater potential in bone tissue regeneration than the delivery of either GFs alone. PMID:27042064

  17. Regulation of physicochemical properties, osteogenesis activity, and fibroblast growth factor-2 release ability of β-tricalcium phosphate for bone cement by calcium silicate.

    PubMed

    Su, Ching-Chuan; Kao, Chia-Tze; Hung, Chi-Jr; Chen, Yi-Jyun; Huang, Tsui-Hsien; Shie, Ming-You

    2014-04-01

    β-Tricalcium phosphate (β-TCP) is an osteoconductive material. For this research we have combined it with a low degradation calcium silicate (CS) to enhance its bioactive and osteostimulative properties. To check its effectiveness, a series of β-TCP/CS composites with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Formation of bone-like apatite, the diametral tensile strength, and weight loss of composites were considered before and after immersion in simulated body fluid (SBF). In addition, we also examined the effects of fibroblast growth factor-2 (FGF-2) released from β-TCP/CS composites and in vitro human dental pulp cell (hDPC) and studied its behavior. The results showed that the apatite deposition ability of the β-TCP/CS composites was enhanced as the CS content was increased. For composites with more than 50% CS contents, the samples were completely covered by a dense bone-like apatite layer. At the end of the immersion point, weight losses of 19%, 24%, 33%, 42%, and 51% were observed for the composites containing 0%, 30%, 50%, 70% and 100% β-TCP cements, respectively. In vitro cell experiments show that the CS-rich composites promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the CS quantity in the composite is less than 70%, the amount of cells and osteogenesis protein of hDPCs was stimulated by FGF-2 released from β-TCP/CS composites. The combination of FGF-2 in degradation of β-TCP and osteogenesis of CS gives a strong reason to believe that these calcium-based composite cements may prove to be promising bone repair materials.

  18. The Effect of Lupinus albus and Calcium Chloride on Growth Performance, Body Composition, Plasma Biochemistry and Meat Quality of Male Pigs Immunized Against Gonadotrophin Releasing Factor

    PubMed Central

    Moore, Karen; Mullan, Bruce; Kim, Jae Cheol; Dunshea, Frank

    2016-01-01

    Simple Summary Pigs immunized against gonadotrophin releasing factor (immunocastrated (IC) males) have an increased feed intake, growth rate, back fat and fat deposition compared to entire males. It is desirable to develop management strategies to limit the increase in feed intake and fat deposition in IC males. This experiment used in-feed ingredients (Lupinus albus (albus lupins) or a combination of calcium chloride and sodium tri-polyphosphate (mineral salts)) to try to suppress the voluntary feed intake of IC male pigs and subsequently fat deposition. Mineral salts decreased feed intake with no effect on fat deposition while albus lupins reduced both feed intake and fat deposition in pigs. Abstract Two hundred and ninety-four pigs were used to assess the effect of two ingredients (Lupinus albus (albus lupins) or a combination of calcium chloride and sodium tri-polyphosphate (mineral salts)) on growth performance, body composition and objective meat quality of pigs immunized against gonadotrophin releasing factor (immunocastrates) and entire male pigs in the late finishing phase. Pigs fed mineral salts ate less feed than those fed the control diet with no effect on growth rate (p > 0.05), backfat (p > 0.05) or fat deposition (p > 0.05). Pigs fed albus lupins had a reduced feed intake (p < 0.001 for all time periods), lower growth rate (p < 0.001 for all time periods), lower backfat (p < 0.005) and decreased fat deposition (p < 0.001 for all time periods) compared to those fed the control diet or mineral salts. From day (d) 0–28 pigs fed mineral salts had a better feed conversion ratio (p = 0.001) than those fed albus lupins who in turn had an improved feed conversion compared to the control diet. Immunocastrates had thicker backfat than entire males at the end of the experiment (p < 0.001), however, feeding albus lupins to immunocastrated males reduced backfat thickness to similar to entire males fed the control diet (p = 0.01). With the exception of the

  19. Transplant of polymer-encapsulated cells genetically engineered to release nerve growth factor allows a normal functional development of the visual cortex in dark-reared rats.

    PubMed

    Pizzorusso, T; Porciatti, V; Tseng, J L; Aebischer, P; Maffei, L

    1997-09-01

    Visual experience is necessary for the normal development of the visual system. Dark-reared mammals show abnormal vision when reintroduced into a normal environment. The absence of visual experience during the critical period results in reduced and/or inappropriate neural responses in visual cortical neurons. The change in electrical activity induced by dark rearing is probably reflected by the modulation of specific unknown molecules. Neurotrophins are present in the developing visual cortex and their production depends on visually driven electrical activity. Recent findings support the possibility that an important link between electrical activity in the visual pathway and correct development of visual properties is represented by neurotrophins. We advance the hypothesis that the visual abnormalities present in dark-reared animals could be due to a decreased production of a neurotrophin secondary to the lack of visual stimulation. We report that some properties of visual cortical response such as receptive field size, orientation selectivity, adaptation to repeated stimulation, response latency and visual acuity are virtually normal in dark-reared rats transplanted with polymer-encapsulated baby hamster kidney cells genetically engineered to release nerve growth factor.

  20. Set-up of large laboratory-scale chromatographic separations of poly(ethylene glycol) derivatives of the growth hormone-releasing factor 1-29 analogue.

    PubMed

    Piquet, G; Gatti, M; Barbero, L; Traversa, S; Caccia, P; Esposito, P

    2002-01-25

    In this paper we report the scale-up of the purification of poly(ethylene glycol) (PEG) derivatives of the growth hormone-releasing factor 1-29, from laboratory scale (100 mg of bulk starting material) to larger scale (3 g of bulk), through the use of a cation-exchange TSK-SP-5PW chromatographic column. A one-step purification process capable of purifying large amounts of mono-PEGylated GRF species from the crude reaction mixture was developed. A simple, straightforward stepwise gradient elution separation was developed at laboratory scale and then scaled up with a larger column packed with a chromatographic resin with the same chemistry which maintained the laboratory-scale separation profile. Active material recovery and material purity remained constant through the scale-up from the 13-microm stationary phase to the 25-microm larger column. Overall, the gram GRF equivalent/batch process scale showed to be quite reproducible, and could be considered as a good platform for scale up to production scale.

  1. OZONE EXPOSURE INITIATES A SEQUENTIAL SIGNALING CASCADE IN AIRWAYS INVOLVING INTERLEUKIN-1BETA RELEASE, NERVE GROWTH FACTOR SECRETION, AND SUBSTANCE P UPREGULATION

    PubMed Central

    Barker, Joshua S.; Wu, Zhongxin; Hunter, Dawn D.; Dey, Richard D.

    2015-01-01

    Previous studies demonstrated that interleukin-1β (IL-1β) and nerve growth factor (NGF) increase synthesis of substance P (SP) in airway neurons both after ozone (O3) exposure and by direct application. It was postulated that NGF mediates O3-induced IL-1β effects on SP. The current study specifically focused on the influence of O3 on IL-1β, NGF, and SP levels in mice bronchoalveolar lavage fluid (BALF) and whether these mediators may be linked in an inflammatory-neuronal cascade in vivo. The findings showed that in vivo O3 exposure induced an increase of all three proteins in mouse BALF and that O3-induced elevations in both NGF and SP are mediated by the inflammatory cytokine IL-1β. Further, inhibition of NGF reduced O3 induced increases of SP in both the lung BALF and lung tissue, demonstrating NGF serves as a mediator of IL-1β effects on SP. These data indicate that IL-1β is an early mediator of O3-induced rise in NGF and subsequent SP release in mice in vivo. PMID:25734767

  2. Effects of the breed, sex and age on cellular content and growth factor release from equine pure-platelet rich plasma and pure-platelet rich gel

    PubMed Central

    2013-01-01

    Background There is no information on the effects of the breed, gender and age on the cellular content and growth factor (GF) release from equine pure-platelet rich plasma (P-PRP) and pure-platelet rich gel (P-PRG). The objectives of this study were: 1) to compare the cellular composition of P-PRP with whole blood and platelet poor plasma (PPP); 2) to compare the concentration of transforming GF beta 1 (TGF-β1) and platelet derived GF isoform BB (PDGF-BB) between P-PRP treated with non-ionic detergent (P-PRP+NID), P-PRG (activated with calcium gluconate -CG-), PPP+NID, PPP gel (PPG), and plasma and; 3) to evaluate and to correlate the effect of the breed, gender and age on the cellular and GF concentration for each blood component. Forty adult horses, 20 Argentinean Creole Horses (ACH) and, 20 Colombian Creole Horses (CCH) were included. Data were analyzed by parametric (i.e.: t-test, one way ANOVA) and non parametric (Kruskal-Wallis test, Wilcoxon test) tests. Correlation analysis was also performed by using the Spearman and Pearson tests. A p ≤ 0.05 was set as significant for all tests. All the blood components were compared for platelet (PLT), leukocyte (WBC), TGF-β1 and PDGF-BB concentrations. The effect of the breed, gender and age on these variables was analyzed. A P ≤ 0.05 was accepted as significant for all the tests. Results PLT counts were 1.8 and 0.6 times higher in P-PRP than in whole blood and PPP, respectively; WBC counts were 0.5 and 0.1 times lower in P-PRP, in comparison with whole blood and PPP, respectively. TGF-β1 and PDGF-BB concentrations were 2.3 and 262 times higher, respectively, in P-PRG than in plasma, and 0.59 and 0.48 times higher, respectively, in P-PRG than in PPG. P-PRG derived from CCH females or young horses presented significantly (P < 0.001) higher PDGF-BB concentrations than P-PRG derived from ACH males or older horses. Conclusions Our results indicated that P-PRP obtained by a manual method was affected by

  3. FGF growth factor analogs

    DOEpatents

    Zamora, Paul O [Gaithersburg, MD; Pena, Louis A [Poquott, NY; Lin, Xinhua [Plainview, NY; Takahashi, Kazuyuki [Germantown, MD

    2012-07-24

    The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

  4. The Effect of Lupinus albus and Calcium Chloride on Growth Performance, Body Composition, Plasma Biochemistry and Meat Quality of Male Pigs Immunized Against Gonadotrophin Releasing Factor.

    PubMed

    Moore, Karen; Mullan, Bruce; Kim, Jae Cheol; Dunshea, Frank

    2016-12-01

    Two hundred and ninety-four pigs were used to assess the effect of two ingredients (Lupinus albus (albus lupins) or a combination of calcium chloride and sodium tri-polyphosphate (mineral salts)) on growth performance, body composition and objective meat quality of pigs immunized against gonadotrophin releasing factor (immunocastrates) and entire male pigs in the late finishing phase. Pigs fed mineral salts ate less feed than those fed the control diet with no effect on growth rate (p > 0.05), backfat (p > 0.05) or fat deposition (p > 0.05). Pigs fed albus lupins had a reduced feed intake (p < 0.001 for all time periods), lower growth rate (p < 0.001 for all time periods), lower backfat (p < 0.005) and decreased fat deposition (p < 0.001 for all time periods) compared to those fed the control diet or mineral salts. From day (d) 0-28 pigs fed mineral salts had a better feed conversion ratio (p = 0.001) than those fed albus lupins who in turn had an improved feed conversion compared to the control diet. Immunocastrates had thicker backfat than entire males at the end of the experiment (p < 0.001), however, feeding albus lupins to immunocastrated males reduced backfat thickness to similar to entire males fed the control diet (p = 0.01). With the exception of the increased muscle pH at 45 minutes post-exsanguination in mineral salts and albus lupins compared with the control diet (p = 0.03) there was no effect of diet on objective pork quality. Pork from IC males had a higher ultimate pH (p < 0.001), was lighter (L*; p = 0.003), more yellow (p = 0.008) and had a higher drip loss (p < 0.001) compared to entire males. Albus lupins show potential in reducing the increase in feed intake and backfat associated with immunocastration. Mineral salts may be useful in situations where a reduction in feed intake and an improvement in feed conversion is desired and reducing fat deposition is not the objective.

  5. Peptide growth factors, part A

    SciTech Connect

    Barnes, D.; Sirbasku, D.A.

    1987-01-01

    This book contains information on the following topics: Epidermal Growth Factor;Transforming Growth Factors;Bone and Cartilage Growth Factors;Somatomedin/Insulin-Like Growth Factors;Techniques for the Study of Growth Factor Activity;Assays, Phosphorylation, and Surface Membrane Effects.

  6. Autocrine growth factors and solid tumor malignancy.

    PubMed Central

    Walsh, J. H.; Karnes, W. E.; Cuttitta, F.; Walker, A.

    1991-01-01

    The ability of malignant cells to escape the constraint that normally regulate cell growth and differentiation has been a primary focus of attention for investigators of cancer cell biology. An outcome of this attention has been the discovery that the protein products of oncogenes play a role in the activation of growth signal pathways. A second outcome, possibly related to abnormal oncogene expression, has been the discovery that malignant cells frequently show an ability to regulate their own growth by the release of autocrine growth modulatory substances. Most important, the growth of certain malignant cell types has been shown to depend on autocrine growth circuits. A malignant tumor whose continued growth depends on the release of an autocrine growth factor may be vulnerable to treatment with specific receptor antagonists or immunoneutralizing antibodies designed to break the autocrine circuit. Information is rapidly emerging concerning autocrine growth factors in selected human solid tissue malignancy. Images PMID:1926844

  7. New microbial growth factor

    NASA Technical Reports Server (NTRS)

    Bok, S. H.; Casida, L. E., Jr.

    1977-01-01

    A screening procedure was used to isolate from soil a Penicillium sp., two bacterial isolates, and a Streptomyces sp. that produced a previously unknown microbial growth factor. This factor was an absolute growth requirement for three soil bacteria. The Penicillium sp. and one of the bacteria requiring the factor, an Arthrobacter sp., were selected for more extensive study concerning the production and characteristics of the growth factor. It did not seem to be related to the siderochromes. It was not present in soil extract, rumen fluid, or any other medium component tested. It appears to be a glycoprotein of high molecular weight and has high specific activity. When added to the diets for a meadow-vole mammalian test system, it caused an increased consumption of diet without a concurrent increase in rate of weight gain.

  8. Gonadotropin-releasing hormone overcomes follicle-stimulating hormone's inhibition of insulin-like growth factor-5 synthesis and promotion of its degradation in rat granulosa cells.

    PubMed

    Onoda, N; Li, D; Mickey, G; Erickson, G; Shimasaki, S

    1995-04-28

    The effect of a gonadotropin-releasing hormone-agonist (GnRH-a) on the synthesis of insulin-like growth factor-binding protein-5 (IGFBP-5), a physiological marker for atresia, was investigated. Granulosa cells obtained from diethylstilbestrol (DES)-treated immature female rats were cultured in serum-free medium for 72 h with GnRH-a and the conditioned media were subjected to immunoblot analysis using rat IGFBP-5 specific antibody. GnRH-a caused a dose-dependent (ED50 = 8.6 x 10(-11) M) accumulation of IGFBP-5, which migrated as 35 (non-glycosylated) and 36 kDa (glycosylated) bands under reducing conditions. A maximally effective dose of GnRH-a (10(-9) M) caused a 4-fold increase in IGFBP-5 accumulation. In contrast, increasing doses of porcine follicle-stimulating hormone (pFSH) caused a biphasic effect on IGFBP-5 accumulation. A low dose of pFSH (0.25 ng/ml) increased and higher doses of pFSH (22.5 ng/ml) decreased the 35 and 36 kDa IGFBP-5 bands. In the presence of high doses of pFSH (20.75 ng/ml), a 22 kDa band corresponding to a cleaved IGFBP-5 fragment appeared in the media. When the granulosa cells were cultured with a saturating dose of pFSH, co-addition of GnRH-a dose dependently inhibited the FSH effects (ED50 = (2.3-3.7) x 10(-10) M). The GnRH-a effects were completely blocked by co-incubation with GnRH-antagonist. IGFBP-5 mRNA accumulation levels were increased by GnRH-a in a dose dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. The vascular endothelial growth factor-induced disruption of gap junctions is relayed by an autocrine communication via ATP release in coronary capillary endothelium.

    PubMed

    Thuringer, Dominique

    2004-12-01

    Little is known concerning how the coordination of Ca(2+) signaling aids in capillary endothelial cell (CEC) functions, such as microvascular permeability and angiogenesis. Previous reports support the major involvement of gap junction (GJ) channels. However, the cell-to-cell communication may not be straightforward, especially if we consider the participation of active molecules released by CEC. In this study, short-term effects of vascular endothelial growth factor (VEGF-165) were compared with those of bradykinin (BK) on gap junction coupling (GJC) and remodeling of connexin-43 (Cx43) and then analyzed for intercellular Ca(2+) signal in primary cultures of coronary CEC. Dye-coupling experiments revealed that BK or VEGF completely blocked GJC. These effects correlated with the rapid internalization of Cx43 and its tyrosine phosphorylation in part via the phosphatidylinositol 3-kinase/Akt pathway. GJC slowly recovered with BK but not with VEGF in the following hour. In control conditions, mechanical stimulation of a single cell within a confluent monolayer triggered an intercellular Ca(2+) wave that was partially inhibited by GJC blockers or purinergic inhibitors. No wave propagation was observed after blockage of both GJC and purinergic receptors. Cell treatment with VEGF also reduced propagation of the Ca(2+) wave, which was totally prevented by applying a purinergic receptor antagonist but not with a GJC blocker. That excludes purine efflux through Cx hemichannels. We conclude that VEGF-induced disruption of GJC via Cx43 remodeling is relayed by an autocrine communication via secretion of ATP to preserve intercellular Ca(2+) signaling in capillary endothelium.

  10. Reversal of diabetes in mice with a bioengineered islet implant incorporating a type I collagen hydrogel and sustained release of vascular endothelial growth factor.

    PubMed

    Vernon, Robert B; Preisinger, Anton; Gooden, Michel D; D'Amico, Leonard A; Yue, Betty B; Bollyky, Paul L; Kuhr, Christian S; Hefty, Thomas R; Nepom, Gerald T; Gebe, John A

    2012-01-01

    We have developed a bioengineered implant (BI) to evaluate strategies to promote graft survival and function in models of islet transplantation in mice. The BI, sized for implantation within a fold of intestinal mesentery, consists of a disk-shaped, polyvinyl alcohol sponge infused with a type I collagen hydrogel that contains dispersed donor islets. To promote islet vascularization, the BI incorporates a spherical alginate hydrogel for sustained release of vascular endothelial growth factor (VEGF). BIs that contained 450-500 islets from syngeneic (C57Bl/6) donors and 20 ng of VEGF reversed streptozotocin (STZ)-induced diabetes in 100% of mice (8/8), whereas BIs that contained an equivalent number of islets, but which lacked VEGF, reversed STZ-induced diabetes in only 62.5% of mice (5/8). Between these "+VEGF" and "-VEGF" groups, the time to achieve normoglycemia (8-18 days after implantation) did not differ statistically; however, transitory, postoperative hypoglycemia was markedly reduced in the +VEGF group relative to the -VEGF group. Notably, none of the mice that achieved normoglycemia in these two groups required exogenous insulin therapy once the BIs began to fully regulate levels of blood glucose. Moreover, the transplanted mice responded to glucose challenge in a near-normal manner, as compared to the responses of healthy, nondiabetic (control) mice that had not received STZ. In future studies, the BIs described here will serve as platforms to evaluate the capability of immunomodulatory compounds, delivered locally within the BI, to prevent or reverse diabetes in the setting of autoimmune (type 1) diabetes.

  11. Reversal of Diabetes in Mice With a Bioengineered Islet Implant Incorporating a Type I Collagen Hydrogel and Sustained Release of Vascular Endothelial Growth Factor

    PubMed Central

    Vernon, Robert B.; Preisinger, Anton; Gooden, Michel D.; D’Amico, Leonard A.; Yue, Betty B.; Bollyky, Paul L.; Kuhr, Christian S.; Hefty, Thomas R.; Nepom, Gerald T.; Gebe, John A.

    2013-01-01

    We have developed a bioengineered implant (BI) to evaluate strategies to promote graft survival and function in models of islet transplantation in mice. The BI, sized for implantation within a fold of intestinal mesentery, consists of a disk-shaped, polyvinyl alcohol sponge infused with a type I collagen hydrogel that contains dispersed donor islets. To promote islet vascularization, the BI incorporates a spherical alginate hydrogel for sustained release of vascular endothelial growth factor (VEGF). BIs that contained 450–500 islets from syngeneic (C57Bl/6) donors and 20 ng of VEGF reversed streptozotocin (STZ)-induced diabetes in 100% of mice (8/8), whereas BIs that contained an equivalent number of islets, but which lacked VEGF, reversed STZ-induced diabetes in only 62.5% of mice (5/8). Between these “+VEGF” and “−VEGF” groups, the time to achieve normoglycemia (8–18 days after implantation) did not differ statistically; however, transitory, postoperative hypoglycemia was markedly reduced in the +VEGF group relative to the −VEGF group. Notably, none of the mice that achieved normoglycemia in these two groups required exogenous insulin therapy once the BIs began to fully regulate levels of blood glucose. Moreover, the transplanted mice responded to glucose challenge in a near-normal manner, as compared to the responses of healthy, nondiabetic (control) mice that had not received STZ. In future studies, the BIs described here will serve as platforms to evaluate the capability of immunomodulatory compounds, delivered locally within the BI, to prevent or reverse diabetes in the setting of autoimmune (type 1) diabetes. PMID:23231959

  12. Control-released basic fibroblast growth factor-loaded poly-lactic-co-glycolic acid microspheres promote sciatic nerve regeneration in rats

    PubMed Central

    Si, Hai-Bo; Zeng, Yi; Lu, Yan-Rong; Cheng, Jing-Qiu; Shen, Bin

    2017-01-01

    Although peripheral nerve injury may result in a loss of function in innervated areas, the most effective method for nerve regeneration remains to be determined. The aim of the present study was to investigate the effect of control-released basic fibroblast growth factor (bFGF)-loaded poly-lactic-co-glycolic acid (PLGA) microspheres on sciatic nerve regeneration following injury in rats. bFGF-PLGA microspheres were prepared and their characteristics were evaluated. The sciatic nerve was segmentally resected to create a 10 mm defect in 36 Sprague Dawley (SD) rats and, following the anastomosis of the nerve ends with a silicone tube, bFGF-PLGA microspheres, free bFGF or PBS were injected into the tube (n=12 in each group). The outcome of nerve regeneration was evaluated using the sciatic function index (SFI), electrophysiological test and histological staining at 6 weeks and 12 weeks post-surgery. The bFGF-PLGA microspheres were successfully synthesized with an encapsulation efficiency of 66.43%. The recovery of SFI and electrophysiological values were significantly greater (P<0.05), and morphological and histological observations were significantly greater (P<0.05) in bFGF-PLGA microspheres and bFGF groups compared with those in the PBS group, and the quickest recovery was observed in the bFGF-PLGA microspheres group. In conclusion, the bFGF-PLGA microspheres may promote nerve regeneration and functional recovery in the sciatic nerve, and may have potential therapeutic applications in peripheral nerve regeneration. PMID:28352311

  13. Comparative growth performance of pigs immunised with a gonadotrophin releasing factor vaccine with surgically castrated pigs and entire boars raised under conventionally managed conditions.

    PubMed

    Fuchs, Thilo; Nathues, Heiko; Koehrmann, Annika; Andrews, Stuart; Brock, Fiona; Klein, Günter; grosse Beilage, Elisabeth

    2011-01-01

    The objective of this study was to determine the effect of using a gonadotrophin releasing factor (GnRF) vaccine on growth performance of male pigs. Vaccinated pigs were compared with surgically castrated pigs and entire males under conventionally managed farm conditions. Male pigs were randomly assigned to three treatment groups: pigs surgically castrated during the first week of life (group "C", n=274), pigs immunised twice during the fattening period with a GnRF vaccine, the first when 13-14 weeks of age and the second when 20-21 weeks of age (group "V" n=280) and entire males (group "E", n=56). Average daily weight gain (ADG) was measured during the study. Additionally, feed conversion ratio (FCR) as defined by feed intake/weight gain and feed consumption was assessed during the fattening period. No difference in the ADG during the fattening period could be determined between "C" and "V". From the start of the study until slaughter at study day 160/173 the ADG in group "E" was lower (625 g/day; P) than in group "C" (681 g/day; P < 0.001) and group "V" (675 g/day; P < 0.01). The FCR during the fattening period until study day 160, three days before the first batch of pigs were slaughtered at 24-25 weeks of age, was higher in group"C" (2.72 kg feed intake/kg weight gain) compared with group "V" (2.44 kg feed intake/kg weight gain; P < 0.001) and group "E" (2.44 kg feed intake/kg weight gain; P <0.01). Pigs in group "V" performed similarly to those in group "E" until the second vaccination (day 135) after which time they showed a substantial increase in feed intake and ADG, while retaining an FCR advantage over group C.

  14. Effect of feed restriction and initial body weight on growth performance, body composition, and hormones in male pigs immunized against gonadotropin-releasing factor.

    PubMed

    Moore, K L; Mullan, B P; Kim, J C; Payne, H G; Dunshea, F R

    2016-09-01

    Pigs immunized against gonadotropin-releasing factor (GnRF) have increased carcass fatness compared to entire males; however, the timing of this increase in fatness after the second immunization against GnRF has not been determined. An experiment was conducted to identify and compare the growth performance, body composition, and physiological changes in immunocastrated males (IC males) at different BW and feeding levels. A total of 64 pigs were used in a 2 × 2 × 2 factorial experiment with the treatments being 1) sex (entire males or IC males), 2) initial BW (45.9 kg [light] or 78.3 kg [heavy]), and 3) feeding regime (2.5 times maintenance [restricted] or ad libitum). The pigs were individually housed, and the diets were fed for 4 wk after the second immunization against GnRF until slaughter at either 68.4 kg BW (light) or 105.8 kg BW (heavy). Immunocastrated males on a restricted feed intake had a lower ADG compared to entire males from d 15 to 28 and d 0 to 28 ( 0.011 and 0.011, respectively). Fat deposition was not affected by sex from d 0 to 14, but from d 15 to 28 IC males deposited 45 g/d more fat than entire males ( = 0.025). Immunocastrated male pigs fed ad libitum deposited 87 g/d more fat from d 15 to 28 than entire males fed ad libitum ( = 0.036). However, there was no difference in fat deposition between IC males and entire males when feed intake was restricted from d 15 to 28. Plasma urea nitrogen levels were greater in IC males compared to entire males from d 7 after the second immunization against GnRF ( 0.05 for d 7, 10, 14, 21, and 28). Plasma concentrations of IGF-1 were lower for IC males compared to entire males on d 3, 7, 10, and 28 ( 0.05 for all days). The following conclusions were made: 1) when pigs are immunized at a light BW (50 kg) and/or are on a restricted feed intake, they have a reduced propensity to deposit fat; however, the restriction in feed intake adversely affects growth rate. 2) The majority of fat deposition for males

  15. Predictors of Treatment Response to Tesamorelin, a Growth Hormone-Releasing Factor Analog, in HIV-Infected Patients with Excess Abdominal Fat

    PubMed Central

    Mangili, Alexandra; Falutz, Julian; Mamputu, Jean-Claude; Stepanians, Miganush; Hayward, Brooke

    2015-01-01

    Background Tesamorelin, a synthetic analog of human growth hormone-releasing factor, decreases visceral adipose tissue (VAT) in human immunodeficiency virus (HIV)-infected patients with lipodystrophy. Objectives 1) To evaluate the utility of patient characteristics and validated disease-risk scores, namely indicator variables for the metabolic syndrome defined by the International Diabetes Federation (MetS-IDF) or the National Cholesterol Education Program (MetS-NCEP) and the Framingham Risk Score (FRS), as predictors of VAT reduction during tesamorelin therapy at 3 and 6 months, and 2) To explore the characteristics of patients who reached a threshold of VAT <140 cm2, a level associated with lower risk of adverse health outcomes, after 6 months of treatment with tesamorelin. Methods Data were analyzed from two Phase 3 studies in which HIV-infected patients with excess abdominal fat were randomized in a 2:1 ratio to receive tesamorelin 2 mg (n = 543) or placebo (n = 263) subcutaneously daily for 6 months, using ANOVA and ANCOVA models. Results Metabolic syndrome (MetS-IDF or MetS-NCEP) and FRS were significantly associated with VAT at baseline. Presence of metabolic syndrome ([MetS-NCEP), triglyceride levels >1.7 mmol/L, and white race had a significant impact on likelihood of response to tesamorelin after 6 months of therapy (interaction p-values 0.054, 0.063, and 0.025, respectively). No predictive factors were identified at 3 months. The odds of a VAT reduction to <140 cm2 for subjects treated with tesamorelin was 3.9 times greater than that of subjects randomized to placebo after controlling for study, gender, baseline body mass index (BMI) and baseline VAT (95% confidence interval [CI] 2.03; 7.44). Conclusions Individuals with baseline MetS-NCEP, elevated triglyceride levels, or white race were most likely to experience reductions in VAT after 6 months of tesamorelin treatment. The odds of response of VAT <140 cm2 was 3.9 times greater for tesamorelin

  16. Central effects of growth hormone-releasing hexapeptide (GHRP-6) on growth hormone release are inhibited by central somatostatin action.

    PubMed

    Fairhall, K M; Mynett, A; Robinson, I C

    1995-03-01

    Growth hormone (GH) release is stimulated by a variety of synthetic secretagogues, of which growth hormone-releasing hexapeptide (GHRP-6) has been most thoroughly studied; it is thought to have actions at both pituitary and hypothalamic sites. To evaluate the central actions of this peptide, we have studied GH release in response to direct i.c.v. injections in anaesthetized guinea pigs. GHRP-6 (0.04-1 microgram) stimulated GH release > 10-fold 30-40 min after i.c.v. injection. The same GH response required > 20-fold more GHRP-6 when given by i.v. injection. GH release could also be elicited by a non-peptide GHRP analogue (L-692,585, 1 microgram i.c.v.), whereas a growth hormone-releasing factor (GRF) analogue (human GRF27Nle(1-29)NH2, 2 micrograms, i.c.v.) was ineffective. A long acting somatostatin analogue (Sandostatin, SMS 201-995, 10 micrograms i.c.v.) (SMS) given 20 min before 200 ng GHRP-6 blocked GH release. This was unlikely to be due to a direct effect of SMS leaking out to the pituitary, since central SMS injections did not affect basal GH release, nor did they block GH release in response to i.v. GRF injections. We conclude that the hypothalamus is a major target for GHRP-6 in vivo. Since the GH release induced by central GHRP-6 injections can be inhibited by a central action of somatostatin, and other data indicate that GHRP-6 activates GRF neurones, we suggest that somatostatin may block this activation via receptors known to be located on or near the GRF cells themselves. Somatostatin may therefore be a functional antagonist of GHRP-6 acting centrally, as well as at the pituitary gland.

  17. Nutrient Sensing Overrides Somatostatin and Growth Hormone-Releasing Hormone to Control Pulsatile Growth Hormone Release.

    PubMed

    Steyn, F J

    2015-07-01

    Pharmacological studies reveal that interactions between hypothalamic inhibitory somatostatin and stimulatory growth hormone-releasing hormone (GHRH) govern pulsatile GH release. However, in vivo analysis of somatostatin and GHRH release into the pituitary portal vasculature and peripheral GH output demonstrates that the withdrawal of somatostatin or the appearance of GHRH into pituitary portal blood does not reliably dictate GH release. Consequently, additional intermediates acting at the level of the hypothalamus and within the anterior pituitary gland are likely to contribute to the release of GH, entraining GH secretory patterns to meet physiological demand. The identification and validation of the actions of such intermediates is particularly important, given that the pattern of GH release defines several of the physiological actions of GH. This review highlights the actions of neuropeptide Y in regulating GH release. It is acknowledged that pulsatile GH release may not occur selectively in response to hypothalamic control of pituitary function. As such, interactions between somatotroph networks, the median eminence and pituitary microvasculature and blood flow, and the emerging role of tanycytes and pericytes as critical regulators of pulsatility are considered. It is argued that collective interactions between the hypothalamus, the median eminence and pituitary vasculature, and structural components within the pituitary gland dictate somatotroph function and thereby pulsatile GH release. These interactions may override hypothalamic somatostatin and GHRH-mediated GH release, and modify pulsatile GH release relative to the peripheral glucose supply, and thereby physiological demand.

  18. Regulation of growth hormone secretion by the growth hormone releasing hexapeptide (GHRP-6).

    PubMed

    Micic, D; Mallo, F; Peino, R; Cordido, F; Leal-Cerro, A; Garcia-Mayor, R V; Casanueva, F F

    1993-01-01

    Growth hormone (GH) secretion is regulated by a complex system of central and peripheral signals. Recently, a new GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) called GHRP-6 which specifically releases GH has been studied. In the present work the mechanism of action of GHRP-6 has been addressed in experimental animal models as well as in obese subjects. GHRP-6 releases GH independently of the hypothalamic factors GHRH and somatostatin and is a powerful GH releaser in obesity.

  19. Effects of short- and long-term dexamethasone treatment on growth and growth hormone (GH)-releasing hormone (GRH)-GH-insulin-like growth factor-I axis in conscious rats.

    PubMed

    Ohyama, T; Sato, M; Niimi, M; Hizuka, N; Takahara, J

    1997-12-01

    Although the inhibitory effects of a chronic excess of glucocorticoids (GC) on body growth and GH secretion are well established, the mechanisms involved remain unclear. In this study, we examined the chronic effects of a high dose of dexamethasone (DEX) on spontaneous GH secretion and insulin-like growth factor (IGF)-I in conscious rats. The animals were given daily i.p. injections of DEX (200 microg/day) for either one or four weeks. Body growth assessed by tibia length and serum IGF-I levels was significantly inhibited 1 week after treatment. By contrast, spontaneous GH secretion was not altered 1 week after the treatment. Neither hypothalamic GRH and somtatostain mRNA levels nor GH responses to GRH from single somatotropes were affected 1 week after the treatment. Four weeks after DEX treatment, body growth of the rats was noticeably suppressed. Interestingly, spontaneous GH secretion, hypothalamic GRH mRNA levels and GH responses to GRH were all inhibited 4 weeks after treatment. Pituitary GRH receptor mRNA levels were not altered 1 week after treatment, but increased after 4 weeks. These results indicate that a high dose of DEX initially impairs IGF-I production and subsequently inhibits spontaneous GH secretion in rats. Inhibition of spontaneous GH secretion resulting from chronic GC excess is due, at least in part, to the impairment of hypothalamic GRH synthesis and pituitary GH responsiveness. An increase in the pituitary GRH receptor may be caused by decreased GRH secretion.

  20. Customized Ca–P/PHBV nanocomposite scaffolds for bone tissue engineering: design, fabrication, surface modification and sustained release of growth factor

    PubMed Central

    Duan, Bin; Wang, Min

    2010-01-01

    Integrating an advanced manufacturing technique, nanocomposite material and controlled delivery of growth factor to form multifunctional tissue engineering scaffolds was investigated in this study. Based on calcium phosphate (Ca–P)/poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanocomposite microspheres, three-dimensional Ca–P/PHBV nanocomposite scaffolds with customized architecture, controlled porosity and totally interconnected porous structure were successfully fabricated using selective laser sintering (SLS), one of the rapid prototyping technologies. The cytocompatibility of sintered Ca–P/PHBV nanocomposite scaffolds, as well as PHBV polymer scaffolds, was studied. For surface modification of nanocomposite scaffolds, gelatin was firstly physically entrapped onto the scaffold surface and heparin was subsequently immobilized on entrapped gelatin. The surface-modification improved the wettability of scaffolds and provided specific binding site between conjugated heparin and the growth factor recombinant human bone morphogenetic protein-2 (rhBMP-2). The surface-modified Ca–P/PHBV nanocomposite scaffolds loaded with rhBMP-2 significantly enhanced the alkaline phosphatase activity and osteogenic differentiation markers in gene expression of C3H10T1/2 mesenchymal stem cells. Together with osteoconductive nanocomposite material and controlled growth factor delivery strategies, the use of SLS technique to form complex scaffolds will provide a promising route towards individualized bone tissue regeneration. PMID:20504805

  1. Customized Ca-P/PHBV nanocomposite scaffolds for bone tissue engineering: design, fabrication, surface modification and sustained release of growth factor.

    PubMed

    Duan, Bin; Wang, Min

    2010-10-06

    Integrating an advanced manufacturing technique, nanocomposite material and controlled delivery of growth factor to form multifunctional tissue engineering scaffolds was investigated in this study. Based on calcium phosphate (Ca-P)/poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanocomposite microspheres, three-dimensional Ca-P/PHBV nanocomposite scaffolds with customized architecture, controlled porosity and totally interconnected porous structure were successfully fabricated using selective laser sintering (SLS), one of the rapid prototyping technologies. The cytocompatibility of sintered Ca-P/PHBV nanocomposite scaffolds, as well as PHBV polymer scaffolds, was studied. For surface modification of nanocomposite scaffolds, gelatin was firstly physically entrapped onto the scaffold surface and heparin was subsequently immobilized on entrapped gelatin. The surface-modification improved the wettability of scaffolds and provided specific binding site between conjugated heparin and the growth factor recombinant human bone morphogenetic protein-2 (rhBMP-2). The surface-modified Ca-P/PHBV nanocomposite scaffolds loaded with rhBMP-2 significantly enhanced the alkaline phosphatase activity and osteogenic differentiation markers in gene expression of C3H10T1/2 mesenchymal stem cells. Together with osteoconductive nanocomposite material and controlled growth factor delivery strategies, the use of SLS technique to form complex scaffolds will provide a promising route towards individualized bone tissue regeneration.

  2. An ex vivo model using human osteoarthritic cartilage demonstrates the release of bioactive insulin-like growth factor-1 from a collagen-glycosaminoglycan scaffold.

    PubMed

    Wardale, J; Mullen, L; Howard, D; Ghose, S; Rushton, N

    2015-07-01

    Biomimetic scaffolds hold great promise for therapeutic repair of cartilage, but although most scaffolds are tested with cells in vitro, there are very few ex vivo models (EVMs) where adult cartilage and scaffolds are co-cultured to optimize their interaction prior to in vivo studies. This study describes a simple, non-compressive method that is applicable to mammalian or human cartilage and provides a reasonable throughput of samples. Rings of full-depth articular cartilage slices were derived from human donors undergoing knee replacement for osteoarthritis and a 3 mm core of a collagen/glycosaminoglycan biomimetic scaffold (Tigenix, UK) inserted to create the EVM. Adult osteoarthritis chondrocytes were seeded into the scaffold and cultures maintained for up to 30 days. Ex vivo models were stable throughout experiments, and cells remained viable. Chondrocytes seeded into the EVM attached throughout the scaffold and in contact with the cartilage explants. Cell migration and deposition of extracellular matrix proteins in the scaffold was enhanced by growth factors particularly if the scaffold was preloaded with growth factors. This study demonstrates that the EVM represents a suitable model that has potential for testing a range of therapeutic parameters such as numbers/types of cell, growth factors or therapeutic drugs before progressing to costly pre-clinical trials.

  3. Effect of Photobiomodulation on Transforming Growth Factor-β1, Platelet-Derived Growth Factor-BB, and Interleukin-8 Release in Palatal Wounds After Free Gingival Graft Harvesting: A Randomized Clinical Study

    PubMed Central

    Lutfioğlu, Muge; Aydogdu, Ahmet; Saygun, N. Isil; Serdar, Muhittin A.

    2016-01-01

    Abstract Objective: This study evaluated the impact of photobiomodulation (PBM) on the healing of the donor palatal area following free gingival graft (FGG) harvesting by examining changes in transforming growth factor (TGF)-β1, platelet-derived growth factor (PDGF)-BB, and interleukin (IL)-8 levels in palatal wound fluid (PWF). Material and methods: Thirty patients were selected and randomly assigned to receive PBM (laser group) or PBM sham (sham group) in the palatine area after FGG harvesting. A neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm) was applied to the test sites immediately after surgery and every 24 h thereafter for 4 days. PWF was collected on Days 7 and 12, and PWF TGF-β1, PDGF-BB, and IL-8 levels were analyzed by enzyme-linked immunosorbent assays (ELISA). Results: PWF TGF-β1, PDGF-BB, and IL-8 levels were significantly lower on Day 12 than on Day 7 for both groups. PWF TGF-β1, PDGF-BB, and IL-8 levels of the laser group were significantly higher than those of sham group on Day 7 (p < 0.05). PWF TGF-β1 levels were also significantly higher in laser group than in the sham group on Day 12; however, differences in PDGF-BB and IL-8 levels between groups on Day 12 were statistically nonsignificant. Conclusions: Observed increases in PWF TGF-β1, PDGF-BB, and IL-8 levels suggest that PBM may accelerate wound healing by stimulating production of selected mediators. PMID:27088277

  4. [Fibroblast growth factor-2].

    PubMed

    Faitová, J

    2004-01-01

    Fibroblast growth factor-2 is a member of a large family of proteins that bind heparin and heparan sulfate and modulate the function of a wide range of cell types. FGF-2 occurs in several isoforms resulting from alternative initiations of traslation: an 18 kDa cytoplasmic isoform and four larger molecular weight nuclear isoforms (22, 22.5, 24 and 34 kDa). It acts mainly through a paracrine/autocrine mechanism involving high affinity transmembrane receptors and heparan sulfate proteoglycan low affinity receptors. It is expressed mostly in tissues of mesoderm and neuroectoderm origin, and plays an important role in mesoderm induction, stimulates the growth and development of the new blood vessels (angiogenesis), normal wound healing and tissue development. FGF-2 positively regulates hematopoiesis by acting on various cellular targets: stromal cells, early and committed hematopoietic progenitors and possibly some mature blood cells. FGF-2 is a potent hematopoietic growth factor that is likely to play an important role in physiological and pathological hematopoiesis.

  5. Locally released retinoic acid leads to facial clefts in the chick embryo but does not alter the expression of receptors for fibroblast growth factor.

    PubMed

    Richman, J M; Delgado, J L

    1995-01-01

    Systemic administration of retinoic acid (RA) affects the growth of the upper beak of chick embryos; however, the mechanism for generating a cleft upper beak is not known. In the present study, we wished to elucidate the molecular basis of the retinoid-induced lip clefting. In order to ensure that facial prominences were locally exposed to levels of retinoid known to affect gene expression, we implanted beads soaked in different concentrations of RA in the right nasal pit or in the centre of the frontonasal mass. Beads soaked in 5 mg/ml RA placed in the right nasal pit caused full clefting of the upper beak with a deviation of the midline toward the right side of the face. The asymmetry was principally due to a decrease in size or total elimination of the right lateral nasal prominence. RA-soaked beads placed in the centre of the frontonasal mass created full bilateral clefts that were more symmetrical than those produced by beads in the nasal pit. Lower concentrations of retinoic acid produced less severe facial abnormalities. Control experiments show that the implanted bead itself has no effect on growth or fusion of the facial prominences. The specific effects of retinoids on facial growth may be due to a localized decrease in responsiveness to growth factors. Gene expression patterns for two fibroblast growth factor receptors (Cek-2, Cek-3, [chicken embryo kinase]) in normal and RA-treated embryos were examined by in situ hybridization. In normal embryos, Cek-2 and Cek-3 transcripts are expressed at very high levels in the mesenchyme directly adjacent to the eye. Cek-3 is additionally expressed in the centre of the frontonasal mass. The application of beads to the right nasal pit did not change the level of expression or distribution of transcripts for Cek-2 or Cek-3. This data suggests that retinoic acid may be affecting other aspects of the FGF receptor-ligand interaction.

  6. Growth Hormone-Releasing Hormone in Diabetes

    PubMed Central

    Fridlyand, Leonid E.; Tamarina, Natalia A.; Schally, Andrew V.; Philipson, Louis H.

    2016-01-01

    Growth hormone-releasing hormone (GHRH) is produced by the hypothalamus and stimulates growth hormone synthesis and release in the anterior pituitary gland. In addition, GHRH is an important regulator of cellular functions in many cells and organs. Expression of GHRH G-Protein Coupled Receptor (GHRHR) has been demonstrated in different peripheral tissues and cell types, including pancreatic islets. Among the peripheral activities, recent studies demonstrate a novel ability of GHRH analogs to increase and preserve insulin secretion by beta-cells in isolated pancreatic islets, which makes them potentially useful for diabetes treatment. This review considers the role of GHRHR in the beta-cell and addresses the unique engineered GHRH agonists and antagonists for treatment of type 2 diabetes mellitus. We discuss the similarity of signaling pathways activated by GHRHR in pituitary somatotrophs and in pancreatic beta-cells and possible ways as to how the GHRHR pathway can interact with glucose and other secretagogues to stimulate insulin secretion. We also consider the hypothesis that novel GHRHR agonists can improve glucose metabolism in Type 2 diabetes by preserving the function and survival of pancreatic beta-cells. Wound healing and cardioprotective action with new GHRH agonists suggest that they may prove useful in ameliorating certain diabetic complications. These findings highlight the future potential therapeutic effectiveness of modulators of GHRHR activity for the development of new therapeutic approaches in diabetes and its complications. PMID:27777568

  7. An ex vivo model using human osteoarthritic cartilage demonstrates the release of bioactive insulin-like growth factor-1 from a collagen–glycosaminoglycan scaffold†

    PubMed Central

    Wardale, J; Mullen, L; Howard, D; Ghose, S; Rushton, N

    2015-01-01

    Biomimetic scaffolds hold great promise for therapeutic repair of cartilage, but although most scaffolds are tested with cells in vitro, there are very few ex vivo models (EVMs) where adult cartilage and scaffolds are co-cultured to optimize their interaction prior to in vivo studies. This study describes a simple, non-compressive method that is applicable to mammalian or human cartilage and provides a reasonable throughput of samples. Rings of full-depth articular cartilage slices were derived from human donors undergoing knee replacement for osteoarthritis and a 3 mm core of a collagen/glycosaminoglycan biomimetic scaffold (Tigenix, UK) inserted to create the EVM. Adult osteoarthritis chondrocytes were seeded into the scaffold and cultures maintained for up to 30 days. Ex vivo models were stable throughout experiments, and cells remained viable. Chondrocytes seeded into the EVM attached throughout the scaffold and in contact with the cartilage explants. Cell migration and deposition of extracellular matrix proteins in the scaffold was enhanced by growth factors particularly if the scaffold was preloaded with growth factors. This study demonstrates that the EVM represents a suitable model that has potential for testing a range of therapeutic parameters such as numbers/types of cell, growth factors or therapeutic drugs before progressing to costly pre-clinical trials. © 2015 The Authors. Cell Biochemistry and Function Published by John Wiley & Sons Ltd. Significance Pre-clinical trials of biomaterials for cartilage repair are very costly, and all too often, studies progress directly from in vitro studies using isolated cells to in vivo studies without investigating the interaction between the target tissue and the scaffold. Our study uses viable cartilage from adult human donors with osteoarthritis and therefore represents the exact scenario that the scaffold is designed for. The system is cheap and simple to set up and is suitable for a 48-well plate format

  8. Growth hormone, growth factors, and acromegaly

    SciTech Connect

    Ludecke, D.K.; Tolis, G.T.

    1987-01-01

    This book contains five sections, each consisting of several papers. The section headings are: Biochemistry and Physiology of GH and Growth Factors, Pathology of Acromegaly, Clinical Endocrinology of Acromegaly, Nonsurgical Therapy of Acromegaly, and Surgical Therapy of Acromegaly.

  9. Growth factor involvement in tension-induced skeletal muscle growth

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman H.

    1993-01-01

    Long-term manned space travel will require a better understanding of skeletal muscle atrophy which results from microgravity. Astronaut strength and dexterity must be maintained for normal mission operations and for emergency situations. Although exercise in space slows the rate of muscle loss, it does not prevent it. A biochemical understanding of how gravity/tension/exercise help to maintain muscle size by altering protein synthesis and/or degradation rate should ultimately allow pharmacological intervention to prevent muscle atrophy in microgravity. The overall objective is to examine some of the basic biochemical processes involved in tension-induced muscle growth. With an experimental in vitro system, the role of exogenous and endogenous muscle growth factors in mechanically stimulated muscle growth are examined. Differentiated avian skeletal myofibers can be 'exercised' in tissue culture using a newly developed dynamic mechanical cell stimulator device which simulates different muscle activity patterns. Patterns of mechanical activity which significantly affect muscle growth and metabolic characteristics were found. Both exogenous and endogenous growth factors are essential for tension-induced muscle growth. Exogenous growth factors found in serum, such as insulin, insulin-like growth factors, and steroids, are important regulators of muscle protein turnover rates and mechanically-induced muscle growth. Endogenous growth factors are synthesized and released into the culture medium when muscle cells are mechanically stimulated. At least one family of mechanically induced endogenous factors, the prostaglandins, help to regulate the rates of protein turnover in muscle cells. Endogenously synthesized IGF-1 is another. The interaction of muscle mechanical activity and these growth factors in the regulation of muscle protein turnover rates with our in vitro model system is studied.

  10. Cigarette smoke extract induces placental growth factor release from human bronchial epithelial cells via ROS/MAPK (ERK-1/2)/Egr-1 axis

    PubMed Central

    Wu, Dong; Yuan, Yalian; Lin, Zhixiu; Lai, Tianwen; Chen, Min; Li, Wen; Lv, Quanchao; Yuan, Binfan; Li, Dongmin; Wu, Bin

    2016-01-01

    Etiological evidence demonstrates that there is a significant association between cigarette smoking and chronic airway inflammatory disease. Abnormal expression of placental growth factor (PlGF) has been reported in COPD, and its downstream signaling molecules have been reported to contribute to the pathogenesis of airway epithelial cell apoptosis and emphysema. However, the signaling mechanisms underlying cigarette smoke extract (CSE)-induced PlGF expression in airway microenvironment remain unclear. Herein, we investigated the effects of reactive oxygen species (ROS)-dependent activation of the mitogen-activated protein kinase (MAPK) (extracellular signal-regulated kinase1/2 [ERK-1/2])/early growth response-1 (Egr-1) pathway on CSE-induced PlGF upregulation in human bronchial epithelium (HBE). The data obtained with quantitative reverse transcription polymerase chain reaction, Western blot, enzyme-linked immunosorbent assay (ELISA) and immunofluorescence staining analyses showed that CSE-induced Egr-1 activation was mainly mediated through production of ROS and activation of the MAPK (ERK-1/2) cascade. The binding of Egr-1 to the PlGF promoter was corroborated by an ELISA-based DNA binding activity assay. These results demonstrate that ROS activation of the MAPK (ERK-1/2)/Egr-1 pathway is a main player in the regulatory mechanism for CSE-induced PlGF production and that the use of an antioxidant could partly abolish these effects. Understanding the mechanisms of PlGF upregulation by CSE in the airway microenvironment may provide rational therapeutic interventions for cigarette smoking-related airway inflammatory diseases. PMID:27980400

  11. Differential effects of central and peripheral administration of growth hormone (GH) and insulin-like growth factor on hypothalamic GH-releasing hormone and somatostatin gene expression in GH-deficient dwarf rats.

    PubMed

    Sato, M; Frohman, L A

    1993-08-01

    The roles of GH and insulin-like growth factor-I (IGF-I) in the regulation of hypothalamic GH-releasing hormone (GRH) and somatostatin (SRIH) gene expression were investigated in the GH-deficient dwarf (dw) rat, in which endogenous feedback signals are lacking. Adult male and female dw rats were treated with GH or IGF-I by systemic (sc) administration or intracerebroventricular (icv) infusion, and hypothalamic GRH and SRIH mRNA were determined by Northern blotting and densitometric analysis. Systemic sc injection of rGH (75 micrograms every 12 h for 3 days) decreased GRH mRNA levels in both sexes. However, systemic sc injection of human IGF-I (150 micrograms every 12 h for 3 days) did not affect GRH mRNA levels in either sex despite significant stimulation of body weight gain. The use of a continuous sc infusion, which normalized serum IGF-I levels, and prolongation of the treatment period to 7 days also failed to change GRH mRNA levels. SRIH mRNA was unaffected by systemic administration of either GH or IGF-I. Continuous icv infusion of GH (1 microgram/h for 7 days) decreased GRH mRNA levels in both sexes, but did not alter SRIH mRNA levels. Continuous icv infusion of IGF-I (100 ng/h for 7 days) decreased GRH mRNA in both sexes. In contrast, SRIH mRNA levels were increased in both sexes. IGF-I decreased GRH mRNA levels at icv infusion rates of 100 and 300 ng/h and stimulated SRIH mRNA levels at infusion rates of 30 and 100 ng/h. Food intake was unaffected at these infusion rates. Changes in GRH and SRIH mRNA levels in response to systemic or central GH and IGF-I administration were similar in both sexes, except that the decrease in GRH mRNA levels produced by the icv infusion of IGF-I was greater in female than in male rats. The results provide evidence for a direct inhibitory feedback effect of GH in the central nervous system on the regulation of hypothalamic GRH gene expression that is independent of peripheral IGF-I. IGF-I feedback, in contrast, appears to

  12. Effects of artemisinin sustained-release granules on mixed alga growth and microcystins production and release.

    PubMed

    Ni, Lixiao; Li, Danye; Hu, Shuzhen; Wang, Peifang; Li, Shiyin; Li, Yiping; Li, Yong; Acharya, Kumud

    2015-12-01

    To safely and effectively apply artemisinin sustained-release granules to control and prevent algal water-blooms, the effects of artemisinin and its sustained-release granules on freshwater alga (Scenedesmus obliquus (S. obliquus) and Microcystis aeruginosa (M. aeruginosa)), as well as the production and release of microcystins (MCs) were studied. The results showed that artemisinin sustained-release granules inhibited the growth of M. aeruginosa (above 95% IR) and S. obliquus (about 90% IR), with M. aeruginosa more sensitive. The artemisinin sustained-release granules had a longer inhibition effect on growth of pure algae and algal coexistence than direct artemisinin dosing. The artemisinin sustained-release granules could decrease the production and release of algal toxins due to the continued stress of artemisinin released from artemisinin sustained-release granules. There was no increase in the total amount of MC-LR in the algal cell culture medium.

  13. LH release and ovulatory response after intramuscular, intravenous, and intrauterine administration of β-nerve growth factor of seminal plasma origin in female llamas.

    PubMed

    Silva, M; Fernández, A; Ulloa-Leal, C; Adams, G P; Berland, M A; Ratto, M H

    2015-10-15

    The objective of the study was to compare the pituitary and ovarian responses after intramuscular, intravenous, or intrauterine administration of β-nerve growth factor (β-NGF) of seminal plasma origin (SP-NGF) in llamas. In experiment 1, mature female llamas with a growing follicle of 7 mm or greater were assigned randomly to four groups (n = 7/group) and given 2 mg of purified SP-NGF in a volume of 2 mL by (1) intramuscular administration, (2) intravenous administration, and (3) intrauterine infusion, or (4) intrauterine infusion of 2 mL of PBS (negative control). Because ovulations were not detected after intrauterine infusion in experiment 1, a second experiment was done to determine if a higher dose of SP-NGF given by intrauterine infusion, similar to a natural dose during copulation, will elicit an ovulatory response. In experiment 2, llamas with a growing follicle of 7 mm or greater were assigned randomly to three groups (n = 6/per group) given an intrauterine infusion of (1) 4 mL of raw seminal plasma, (2) 4 mL of PBS containing 20 mg of purified llama SP-NGF, or 3) 4 mL of PBS (negative control). In both experiments, the ovaries were examined daily by transrectal ultrasonography using a B-mode scanner and power Doppler mode to detect ovulation and to monitor CL growth, regression, and vascularization. Blood samples were collected to determine plasma LH and progesterone concentrations. In experiment 1, only llamas treated by intramuscular or intravenous administration of SP-NGF ovulated (7 of 7 and 6 of 7, respectively). Plasma LH concentration did not differ between the intramuscular and intravenous SP-NGF-treated groups, nor did CL diameter, CL vascularization, or plasma progesterone concentration profiles. In experiment 2, the ovulation rate was 100% for llamas treated by intrauterine infusion of raw seminal plasma or llama SP-NFG, whereas no ovulations were detected in females treated with PBS. Plasma LH concentrations did not differ between groups

  14. Reducing the length of time between slaughter and the secondary gonadotropin-releasing factor immunization improves growth performance and clears boar taint compounds in male finishing pigs.

    PubMed

    Lealiifano, A K; Pluske, J R; Nicholls, R R; Dunshea, F R; Campbell, R G; Hennessy, D P; Miller, D W; Hansen, C F; Mullan, B P

    2011-09-01

    The objective of this study was to evaluate whether altering the timing of the secondary anti-gonadotropin-releasing factor (GnRF) immunization closer to slaughter in male finishing pigs would reduce the increase in P2 fat depth (6.5 cm from the midline over the last rib), while still limiting the incidence of boar taint. Entire male pigs are immunized against GnRF to reduce the concentration of testicular steroids that in turn limits the incidence of boar taint. Additionally, testicle measurements and color measurements were taken to examine whether they could be used to differentiate nonimmunized entire males from immunized male pigs. A total of 175 Large White × Landrace entire male pigs aged 16 wk (59 kg of BW) were used in a completely randomized design with 5 treatment groups based on the time that pigs received the secondary immunization before slaughter. Pigs were housed in groups of 7 and randomly allocated to 1 of 5 treatments with 5 replicates per treatment. The treatment groups were as follows: no secondary immunization before slaughter, and the secondary immunization given at 2, 3, 4, or 6 wk before slaughter. The P2 fat depth levels were reduced (P = 0.054) with the secondary immunization closer to slaughter (11.7, 11.3, 12.8, 12.6, and 13.7 mm for no secondary immunization, secondary immunization at 2, 3, 4, and 6 wk before slaughter, respectively). Androstenone concentration did not exceed the generally accepted industry sensory threshold of 1.0 µg/g of fat, and both androstenone concentration in the adipose tissue and testosterone concentrations in the blood were suppressed (P < 0.001) in all immunized pigs regardless of timing of the secondary immunization compared with pigs that did not receive the secondary immunization. Skatole concentration of all pigs in the experiment did not exceed the generally accepted industry sensory threshold of 0.2 µg/g. Testes weight was reduced (P < 0.001) with increased time between slaughter and the secondary

  15. Comparison of the effect of calcium gluconate and batroxobin on the release of transforming growth factor beta 1 in canine platelet concentrates

    PubMed Central

    2012-01-01

    Background The clinical use of autologous platelet concentrates (also known as platelet-rich plasma) on the field of regenerative therapy, in the last decade has been the subject of several studies especially in equine medicine and surgery. The objectives of this study was: 1) to describe and compare the cellular population in whole blood, lower fraction (A) and upper fraction (B) of platelet concentrates, 2) to measure and compare the transforming growth factor beta 1 (TGF-β1) concentration in plasma and both platelet concentrates after be activated with calcium gluconate or batroxobin plus calcium gluconate and, 3) to determine correlations between cell counts in platelet concentrates and concentrations of TGF-β1. Blood samples were taken from 16 dogs for complete blood count, plasma collection and platelet concentrates preparation. The platelet concentrates (PC) were arbitrarily divided into two fractions, specifically, PC-A (lower fraction) and PC-B (upper fraction). The Platelet concentrates were analyzed by hemogram. After activated with calcium gluconate or batroxobin plus calcium gluconate, TGF-β1 concentration was determined in supernatants of platelet concentrates and plasma. Results There were differences statistically significant (P < 0.05) for the platelet count and leukocyte count and TGF-β1 concentration between whole blood, plasma and both platelet concentrates. A significant correlation was found between the number of platelets in both platelet concentrates and TGF-β1 concentration. Platelet collection efficiency was 46.34% and 28.16% for PC-A and PC-B, respectively. TGF-β1 concentration efficiency for PC activated with calcium gluconate was 47.75% and 31.77%, for PC-A and PC-B, respectively. PC activated with batroxobin plus CG showed 46.87% and 32.24% for PC-A and PC-B, respectively. Conclusions The methodology used in this study allows the concentration of a number of platelets and TGF-β1 that might be acceptable for a biological

  16. Epidermal growth factor (EGF) ligand release by substrate-specific a disintegrin and metalloproteases (ADAMs) involves different protein kinase C (PKC) isoenzymes depending on the stimulus.

    PubMed

    Dang, Michelle; Dubbin, Karen; D'Aiello, Antonio; Hartmann, Monika; Lodish, Harvey; Herrlich, Andreas

    2011-05-20

    The dysregulation of EGF family ligand cleavage has severe consequences for the developing as well as the adult organism. Therefore, their production is highly regulated. The limiting step is the ectodomain cleavage of membrane-bound precursors by one of several a disintegrin and metalloprotease (ADAM) metalloproteases, and understanding the regulation of cleavage is an important goal of current research. We have previously reported that in mouse lung epithelial cells, the pro-EGF ligands TGFα, neuregulin 1β (NRG), and heparin-binding EGF are differentially cleaved depending on the cleavage stimulus (Herrlich, A., Klinman, E., Fu, J., Sadegh, C., and Lodish, H. (2008) FASEB J.). In this study in mouse embryonic fibroblasts that lack different ADAMs, we show that induced cleavage of EGF ligands can involve the same substrate-specific metalloprotease but does require different stimulus-dependent signaling pathways. Cleavage was stimulated by phorbol ester (12-O-tetradecanoylphorbol-13-acetate (TPA), a mimic of diacylglycerol and PKC activator), hypertonic stress, lysophosphatidic acid (LPA)-induced G protein-coupled receptor activation, or by ionomycin-induced intracellular calcium release. Although ADAMs showed substrate preference (ADAM17, TGFα and heparin-binding EGF; and ADAM9, NRG), substrate cleavage differed substantially with the stimulus, and cleavage of the same substrate depended on the presence of different, sometimes multiple, PKC isoforms. For instance, classical PKC was required for TPA-induced but not hypertonic stress-induced cleavage of all EGF family ligands. Inhibition of PKCζ enhanced NRG release upon TPA stimulation, but it blocked NRG release in response to hypertonic stress. Our results suggest a model in which substantial regulation of ectodomain cleavage occurs not only on the metalloprotease level but also on the level of the substrate or of a third protein.

  17. Superoxide radicals increase transforming growth factor-{beta}1 and collagen release from human lung fibroblasts via cellular influx through chloride channels

    SciTech Connect

    Qi Shufan Hartog, Gertjan J.M. den; Bast, Aalt

    2009-05-15

    Reactive oxygen species (ROS) have been implicated in the pathogenesis of fibrosis. However, it remains unclear which ROS is the major cause. We hypothesize that superoxide elicits specific toxicity to human lung fibroblasts and plays an important role in the development of pulmonary fibrosis. In this study, superoxide generated from xanthine and xanthine oxidase activated lung fibroblasts by increasing the release of TGF-{beta}1 and collagen. This was associated with increased levels of intracellular superoxide. SOD and tempol, by scavenging respectively extracellular and intracellular superoxide, prevented the activation of fibroblasts induced by exposure to exogenous superoxide, whereas catalase did not. Moreover, hydrogen peroxide did not activate fibroblasts. Apparently, superoxide rather than hydrogen peroxide is involved in the regulation of TGF-{beta}1 and collagen release in lung fibroblasts. The chloride channel blocker, DIDS, inhibited the increase of intracellular superoxide levels induced by exogenous superoxide and consequently prevented the activation of fibroblasts. This suggests that the cellular influx of superoxide through chloride channels is essential for superoxide-induced activation of fibroblasts. ERK1/2 and p38 MAPKs are involved in the intracellular pathway leading to superoxide-induced fibroblasts activation. Superoxide possesses until now undiscovered specific pro-fibrotic properties in human lung fibroblasts. This takes place via the cellular influx of superoxide through chloride channels rather than via the formation of hydrogen peroxide.

  18. Impairments in brain-derived neurotrophic factor-induced glutamate release in cultured cortical neurons derived from rats with intrauterine growth retardation: possible involvement of suppression of TrkB/phospholipase C-γ activation.

    PubMed

    Numakawa, Tadahiro; Matsumoto, Tomoya; Ooshima, Yoshiko; Chiba, Shuichi; Furuta, Miyako; Izumi, Aiko; Ninomiya-Baba, Midori; Odaka, Haruki; Hashido, Kazuo; Adachi, Naoki; Kunugi, Hiroshi

    2014-04-01

    Low birth weight due to intrauterine growth retardation (IUGR) is suggested to be a risk factor for various psychiatric disorders such as schizophrenia. It has been reported that developmental cortical dysfunction and neurocognitive deficits are observed in individuals with IUGR, however, the underlying molecular mechanisms have yet to be elucidated. Brain-derived neurotrophic factor (BDNF) and its receptor TrkB are associated with schizophrenia and play a role in cortical development. We previously demonstrated that BDNF induced glutamate release through activation of the TrkB/phospholipase C-γ (PLC-γ) pathway in developing cultured cortical neurons, and that, using a rat model for IUGR caused by maternal administration of thromboxane A2, cortical levels of TrkB were significantly reduced in IUGR rats at birth. These studies prompted us to hypothesize that TrkB reduction in IUGR cortex led to impairment of BDNF-dependent glutamatergic neurotransmission. In the present study, we found that BDNF-induced glutamate release was strongly impaired in cultured IUGR cortical neurons where TrkB reduction was maintained. Impairment of BDNF-induced glutamate release in IUGR neurons was ameliorated by transfection of human TrkB (hTrkB). Although BDNF-stimulated phosphorylation of TrkB and of PLC-γ was decreased in IUGR neurons, the hTrkB transfection recovered the deficits in their phosphorylation. These results suggest that TrkB reduction causes impairment of BDNF-stimulated glutamatergic function via suppression of TrkB/PLC-γ activation in IUGR cortical neurons. Our findings provide molecular insights into how IUGR links to downregulation of BDNF function in the cortex, which might be involved in the development of IUGR-related diseases such as schizophrenia.

  19. Regulated release of serotonin from axonal growth cones isolated from the fetal rat brain.

    PubMed

    Mercado, R; Floran, B; Hernandez, J

    1998-01-01

    In the present work we propose an hypothetical model related to a molecular recognizing system for serotonin in isolated growth cone particles. This model is supported by previous results from our laboratory plus new ones which show that growth cones release serotonin tonically and such release can be stimulated by potassium in a calcium-dependent manner. The present results, together with other author's data, suggest a physiological basis for the putative role of serotonin as a trophic factor during nervous system development.

  20. Central corticotropin releasing factor and social stress

    PubMed Central

    Backström, Tobias; Winberg, Svante

    2013-01-01

    Social interactions are a main source of stress in vertebrates. Social stressors, as well as other stressors, activate the hypothalamic–pituitary–adrenal (HPA) axis resulting in glucocorticoid release. One of the main components of the HPA axis is corticotropin releasing factor (CRF). The neuropeptide CRF is part of a peptide family including CRF, urocortin 1–3, urotensin 1–3, and sauvagine. The actions of the CRF family are mediated by at least two different receptors with different anatomical distribution and affinities for the peptides. The CRF peptides affect several behavioral and physiological responses to stress including aggression, feeding, and locomotor activity. This review will summarize recent research in vertebrates concerning how social stress interacts with components of the CRF system. Consideration will be taken to the different models used for social stress ranging from social isolation, dyadic interactions, to group dominance hierarchies. Further, the temporal effect of social stressor from acute, intermittent, to chronic will be considered. Finally, strains selected for specific behavior or physiology linked to social stress will also be discussed. PMID:23847465

  1. Interstitial fibrosis and growth factors.

    PubMed Central

    Lasky, J A; Brody, A R

    2000-01-01

    Interstitial pulmonary fibrosis (IPF) is scarring of the lung caused by a variety of inhaled agents including mineral particles, organic dusts, and oxidant gases. The disease afflicts millions of individuals worldwide, and there are no effective therapeutic approaches. A major reason for this lack of useful treatments is that few of the molecular mechanisms of disease have been defined sufficiently to design appropriate targets for therapy. Our laboratory has focused on the molecular mechanisms through which three selected peptide growth factors could play a role in the development of IPF. Hundreds of growth factors and cytokines could be involved in the complex disease process. We are studying platelet-derived growth factor because it is the most potent mesenchymal cell mitogen yet described, transforming growth factor beta because it is a powerful inducer of extracellular matrix (scar tissue) components by mesenchymal cells, and tumor necrosis factor alpha because it is a pleiotropic cytokine that we and others have shown is essential for the development of IPF in animal models. This review describes some of the evidence from studies in humans, in animal models, and in vitro, that supports the growth factor hypothesis. The use of modern molecular and transgenic technologies could elucidate those targets that will allow effective therapeutic approaches. Images Figure 1 Figure 2 PMID:10931794

  2. Growth factors in synaptic function

    PubMed Central

    Poon, Vivian Y.; Choi, Sojoong; Park, Mikyoung

    2013-01-01

    Synapses are increasingly recognized as key structures that malfunction in disorders like schizophrenia, mental retardation, and neurodegenerative diseases. The importance and complexity of the synapse has fuelled research into the molecular mechanisms underlying synaptogenesis, synaptic transmission, and plasticity. In this regard, neurotrophic factors such as netrin, Wnt, transforming growth factor-β (TGF-β), tumor necrosis factor-α (TNF-α), and others have gained prominence for their ability to regulate synaptic function. Several of these factors were first implicated in neuroprotection, neuronal growth, and axon guidance. However, their roles in synaptic development and function have become increasingly clear, and the downstream signaling pathways employed by these factors have begun to be elucidated. In this review, we will address the role of these factors and their downstream effectors in synaptic function in vivo and in cultured neurons. PMID:24065916

  3. Heparin-binding epidermal growth factor-like growth factor promotes neuroblastoma differentiation.

    PubMed

    Gaviglio, Angela L; Knelson, Erik H; Blobe, Gerard C

    2017-02-07

    High-risk neuroblastoma is characterized by undifferentiated neuroblasts and low Schwannian stroma content. The tumor stroma contributes to the suppression of tumor growth by releasing soluble factors that promote neuroblast differentiation. Here we identify heparin-binding epidermal growth factor-like growth factor (HBEGF) as a potent prodifferentiating factor in neuroblastoma. HBEGF mRNA expression is decreased in human neuroblastoma tumors compared with benign tumors, with loss correlating with decreased survival. HBEGF protein is expressed only in stromal compartments of human neuroblastoma specimens, with tissue from high-stage disease containing very little stroma or HBEGF expression. In 3 human neuroblastoma cell lines (SK-N-AS, SK-N-BE2, and SH-SY5Y), soluble HBEGF is sufficient to promote neuroblast differentiation and decrease proliferation. Heparan sulfate proteoglycans and heparin derivatives further enhance HBEGF-induced differentiation by forming a complex with the epidermal growth factor receptor, leading to activation of the ERK1/2 and STAT3 pathways and up-regulation of the inhibitor of DNA binding transcription factor. These data support a role for loss of HBEGF in the neuroblastoma tumor microenvironment in neuroblastoma pathogenesis.-Gaviglio, A. L., Knelson, E. H., Blobe, G. C. Heparin-binding epidermal growth factor-like growth factor promotes neuroblastoma differentiation.

  4. Short- and long-term peripheral nerve regeneration using a poly-lactic-co-glycolic-acid scaffold containing nerve growth factor and glial cell line-derived neurotrophic factor releasing microspheres.

    PubMed

    de Boer, Ralph; Borntraeger, Andreas; Knight, Andrew M; Hébert-Blouin, Marie-Noëlle; Spinner, Robert J; Malessy, Martijn J A; Yaszemski, Michael J; Windebank, Anthony J

    2012-08-01

    Addition of neural growth factors to bioengineered scaffolds may improve peripheral nerve regeneration. The aim of this study is to evaluate the short- and long term effect of microsphere delivered nerve growth factor (NGF) and glial cell derived neurotrophic factor (GDNF) in the 10 mm rat sciatic nerve gap. Eighty-four rats were assigned to seven groups (n = 6) at two endpoints (6 and 16 weeks): saline, saline NGF, saline NGF-microspheres, saline GDNF, saline GDNF-microspheres, saline blank microspheres, and autologous nerve graft. Total fascicular area and total number of myelinated fibers at mid-tube increased in all conduit groups between 6 and 16 weeks. Autologous, saline NGF-microsphere and saline GDNF-microsphere groups reached maximal histomorphometric values by 6 weeks (p < 0.05). Compound muscle action potentials returned after 6 weeks for the autologous graft and continued to increase to a level of 3.6 ± 1.9 mV at endpoint. No significant differences were found between study groups as measured by ankle angle. These experiments show an initial beneficial effect of incorporation of NGF- or GDNF-microspheres in a PLGA 85/15 nerve conduit, since histomorphometric values reached their maximum by 6 weeks compared to control groups. These results do not yet extrapolate into improved electrophysiological or functional improvement.

  5. Effect of an extract based on the medicinal mushroom Agaricus blazei murill on release of cytokines, chemokines and leukocyte growth factors in human blood ex vivo and in vivo.

    PubMed

    Johnson, E; Førland, D T; Saetre, L; Bernardshaw, S V; Lyberg, T; Hetland, G

    2009-03-01

    An immunostimulatory extract based on the medicinal mushroom Agaricus blazei Murill (AbM) has been shown to stimulate mononuclear phagocytes in vitro to produce pro-inflammatory cytokines, and to protect against lethal peritonitis in mice. The present aim was to study the effect of AbM on release of several cytokines in human whole blood both after stimulation ex vivo and in vivo after oral intake over several days in healthy volunteers. The 17 signal substances examined were; T helper 1 (Th1) cytokines [interleukin (IL)-2, interferon (IFN)-gamma and IL-12], T helper 2 cytokines (IL-4, IL-5 and IL-13), pleiotropic (IL-7, IL-17), pro-inflammatory [IL-1beta, IL-6, tumour necrosis factor (TNF)-alpha (mainly produced by Th1 cells)]--and anti-inflammatory (IL-10) cytokines, chemokines [IL-8, macrophage inhibitory protein (MIP)-1beta and monocyte chemoattractant protein (MCP)-1] and leukocyte growth factors [granulocyte colony-stimulating factor (G-CSF), granulocyte/macrophage colony stimulating factor]. After stimulation of whole blood ex vivo with 0.5-5.0% of a mushroom extract, AndoSan mainly containing AbM, there was a dose-dependent increase in all the cytokines studied, ranging from two to 399-fold (TNF-alpha). However, in vivo in the eight volunteers who completed the daily intake (60 ml) of this AbM extract for 12 days, a significant reduction was observed in levels of IL-1beta (97%), TNF-alpha (84%), IL-17 (50%) and IL-2 (46%). Although not significant, there was a trend towards reduced levels for IL-8, IFN-gamma and G-CSF, whilst those of the remaining nine cytokines tested, were unaltered. The discrepant results on cytokine release ex vivo and in vivo may partly be explained by the antioxidant activity of AbM in vivo and limited absorption of its large, complex and bioactive beta-glucans across the intestinal mucosa to the reticuloendothelial system and blood.

  6. Factors controlling gastric-glucagon release.

    PubMed Central

    Lefèbvre, P J; Luyckx, A S

    1977-01-01

    A system consisting of an isolated dog stomach perfused with whole blood has been designed to study gastric glucagon secretion. Under basal conditions, gastric glucagon release was 0.0-3.1 ng glucagon/100g of stomach per min. Arginine, at an arterial plasma concentration averaging 10 mM, elicited a rapid glucagon release. This gastric glucagon release was almost completely abolished by somatostatin (100 ng/ml). The release of gastric glucagon was not affected by hyperglycemia alone but was reduced by about 40% when hyperglycemia was concomitant with an hyperinsulinemia within the physiological range. These observations support the concept that adequate concentrations of insulin are necessary in order for hyperglycemia to inhibit gastric glucagon secretion. Furthermore, it is suggested that the isolated perfused dog stomach might provide a unique tool permitting investigation of alpha-cell function in the absence of endogenously released insulin. PMID:845258

  7. Mental illness, criminal risk factors and parole release decisions.

    PubMed

    Matejkowski, Jason; Draine, Jeffrey; Solomon, Phyllis; Salzer, Mark S

    2011-01-01

    Research has not examined whether higher rates of parole denial among inmates with mental illness (MI) are the result of the increased presence of criminal risk factors among this population. Employing a representative sample of inmates with (n  =  219) and without (n  =  184) MI receiving parole release decisions in 2007, this study tested whether the central eight risk factors for recidivism considered in parole release decisions intervened in the relationship between MI and parole release. MI was associated with possession of a substance use disorder, antisocial personality disorder and violent charges while incarcerated; however, these factors were not related to release decisions. MI was found to have neither a direct nor an indirect effect on release decisions. While results indicate that release decisions appear, to some extent, to be evidence-based, they also suggest considerable discretion is being implemented by parole board members in release decisions above and beyond consideration of criminal risk factors.

  8. Site-specific PEGylation for high-yield preparation of Lys(21)-amine PEGylated growth hormone-releasing factor (GRF) (1-29) using a GRF(1-29) derivative FMOC-protected at Tyr(1) and Lys(12).

    PubMed

    Youn, Yu Seok; Lee, Kang Choon

    2007-01-01

    PEGylation has been viewed as an effective means of overcoming the therapeutic restriction of growth hormone-releasing factor (1-29) (GRF(1-29)) due to its short biological lifetime caused by severe proteolysis and rapid glomerular filtration. Of three isomers according to the PEGylation sites (Tyr1, Lys12, or Lys21), PEGylated GRF(1-29) at Lys21-amine (Lys21-PEG-GRF(1-29)) was shown to have the highest bioactivity. In this report, we propose a unique two-step site-specific PEGylation method capable of producing only Lys21-PEG-GRF(1-29) with a single composition in high yield using a GRF(1-29) derivative protected at Tyr1 and Lys12 and remained available at Lys21 (FMOC1,12-GRF(1-29)). The first step of this reaction involved the PEG attachment to FMOC1,12-GRF(1-29), and the second step involved the removal of FMOC moieties. This PEGylation process was optimized at the following conditions: 0.2-0.3% (v/v) triethylamine concentration, 5.0-6.0-fold molar amount of PEG, reaction temperature of 25-45 degrees C, and reaction time of 30 min. Under these conditions, the maximum yield of Lys21-PEG-GRF(1-29) produced was ca. approximately 95%, 6.3-fold higher than that by nonspecific PEGylation at pH 8.5. Significantly, this site-specific Lys21-PEG-GRF(1-29) was found to have greatly increased resistance to rat plasma, liver, and kidney homogenates, with 7.0-, 25.4-, and 16.4-fold longer half-lives vs GRF(1-29), respectively. Furthermore, 125I-Lys21-PEG-GRF(1-29) displayed significantly reduced liver and kidney distributions and extended blood presence vs 125I-GRF(1-29) in rats. Due to these benefits, Lys21-PEG-GRF(1-29) displayed an enhanced initial growth hormone release in vivo despite having 15% remaining activity in vitro. This devised PEGylation method using an FMOC-protection/deprotection strategy would provide great usefulness for PEGylating bioactive peptides in terms of improved biological potency, elevated production yield, and a uniform composition.

  9. Effects of ghrelin, growth hormone-releasing peptide-6, and growth hormone-releasing hormone on growth hormone, adrenocorticotropic hormone, and cortisol release in type 1 diabetes mellitus.

    PubMed

    de Sá, Larissa Bianca Paiva Cunha; Nascif, Sergio Oliva; Correa-Silva, Silvia Regina; Molica, Patricia; Vieira, José Gilberto Henriques; Dib, Sergio Atala; Lengyel, Ana-Maria Judith

    2010-10-01

    In type 1 diabetes mellitus (T1DM), growth hormone (GH) responses to provocative stimuli are normal or exaggerated, whereas the hypothalamic-pituitary-adrenal axis has been less studied. Ghrelin is a GH secretagogue that also increases adrenocorticotropic hormone (ACTH) and cortisol levels, similarly to GH-releasing peptide-6 (GHRP-6). Ghrelin's effects in patients with T1DM have not been evaluated. We therefore studied GH, ACTH, and cortisol responses to ghrelin and GHRP-6 in 9 patients with T1DM and 9 control subjects. The GH-releasing hormone (GHRH)-induced GH release was also evaluated. Mean fasting GH levels (micrograms per liter) were higher in T1DM (3.5 ± 1.2) than in controls (0.6 ± 0.3). In both groups, ghrelin-induced GH release was higher than that after GHRP-6 and GHRH. When analyzing Δ area under the curve (ΔAUC) GH values after ghrelin, GHRP-6, and GHRH, no significant differences were observed in T1DM compared with controls. There was a trend (P = .055) to higher mean basal cortisol values (micrograms per deciliter) in T1DM (11.7 ± 1.5) compared with controls (8.2 ± 0.8). No significant differences were seen in ΔAUC cortisol values in both groups after ghrelin and GHRP-6. Mean fasting ACTH values were similar in T1DM and controls. No differences were seen in ΔAUC ACTH levels in both groups after ghrelin and GHRP-6. In summary, patients with T1DM have normal GH responsiveness to ghrelin, GHRP-6, and GHRH. The ACTH and cortisol release after ghrelin and GHRP-6 is also similar to controls. Our results suggest that chronic hyperglycemia of T1DM does not interfere with GH-, ACTH-, and cortisol-releasing mechanisms stimulated by these peptides.

  10. [Neuronal growth factors--neurotrophins].

    PubMed

    Meyer, M; Rasmussen, J Z

    1999-04-05

    Neurotrophic factors are polypeptides primarily known to regulate the survival and differentiation of nerve cells during the development of the peripheral and central nervous systems. The neurotrophic factors act via specific receptors after retrograde axonal transport from the nerve fibre target areas back to the cell bodies, and locally through autocrine and paracrine mechanisms linked to nerve cell activity. In the mature nervous system, neurotrophic factors maintain morphological and neurochemical characteristics of nerve cells and promote activity-dependent dynamic/plastic changes in the synaptic contacts between nerve cells by strengthening functionally active synaptic connections. Induction and increased production of neurotrophic factors in relation to neural injuries are thought to serve protective and reparative purposes. Specific neurotrophic factors have thus been shown to protect nerve cells in a number of experimental models for neurodegenerative diseases, such as Parkinson disease, Alzheimer disease, and amyotrophic lateral sclerosis, just as specific neurotrophic factors have been shown to stimulate regenerative growth of both peripheral and central nerve fibres. Today, problems with continuous and localized delivery of specific neurotrophins or combinations thereof into the nervous system appear to be the most important obstacle for more widespread clinical application.

  11. Nerve growth factor promotes human hemopoietic colony growth and differentiation.

    PubMed Central

    Matsuda, H; Coughlin, M D; Bienenstock, J; Denburg, J A

    1988-01-01

    Nerve growth factor (NGF) is a neurotropic polypeptide necessary for the survival and growth of some central neurons, as well as sensory afferent and sympathetic neurons. Much is now known of the structural and functional characteristics of NGF, whose gene has recently been cloned. Since it is synthesized in largest amounts by the male mouse submandibular gland, its role exclusively in nerve growth is questionable. NGF also causes histamine release from rat peritoneal mast cells in vitro, and we have shown elsewhere that it causes significant, dose-dependent, generalized mast cell proliferation in the rat in vivo when administered neonatally. Our experiments now indicate that NGF causes a significant stimulation of granulocyte colonies grown from human peripheral blood in standard hemopoietic methylcellulose assays. Further, NGF appears to act in a relatively selective fashion to induce the differentiation of eosinophils and basophils/mast cells. Depletion experiments show that the NGF effect may be T-cell dependent and that NGF augments the colony-stimulating effect of supernatants from the leukemic T-cell (Mo) line. The hemopoietic activity of NGF is blocked by polyclonal and monoclonal antibodies to NGF. We conclude that NGF may indirectly act as a local growth factor in tissues other than those of the nervous system by causing T cells to synthesize or secrete molecules with colony-stimulating activity. In view of the synthesis of NGF in tissue injury, the involvement of basophils/mast cells and eosinophils in allergic and other inflammatory processes, and the association of mast cells with fibrosis and tissue repair, we postulate that NGF plays an important biological role in a variety of repair processes. PMID:3413109

  12. Growth hormone (GH)-releasing activity of chicken GH-releasing hormone (GHRH) in chickens.

    PubMed

    Harvey, S; Gineste, C; Gaylinn, B D

    2014-08-01

    Two peptides with sequence similarities to growth hormone releasing hormone (GHRH) have been identified by analysis of the chicken genome. One of these peptides, chicken (c) GHRH-LP (like peptide) was previously found to poorly bind to chicken pituitary membranes or to cloned and expressed chicken GHRH receptors and had little, if any, growth hormone (GH)-releasing activity in vivo or in vitro. In contrast, a second more recently discovered peptide, cGHRH, does bind to cloned and expressed cGHRH receptors and increases cAMP activity in transfected cells. The possibility that this peptide may have in vivo GH-releasing activity was therefore assessed. The intravenous (i.v.) administration of cGHRH to immature chickens, at doses of 3-100 μg/kg, significantly increased circulating GH concentrations within 10 min of injection and the plasma GH levels remained elevated for at least 30 min after the injection of maximally effective doses. The plasma GH responses to cGHRH were comparable with those induced by human (h) or porcine (p) GHRH preparations and to that induced by thyrotropin releasing hormone (TRH). In marked contrast, the i.v. injection of cGHRH-LP had no significant effect on circulating GH concentrations in immature chicks. GH release was also increased from slaughterhouse chicken pituitary glands perifused for 5 min with cGHRH at doses of 0.1 μg/ml or 1.0 μg/ml, comparable with GH responses to hGHRH1-44. In contrast, the perifusion of chicken pituitary glands with cGHRH-LP had no significant effect on GH release. In summary, these results demonstrate that cGHRH has GH-releasing activity in chickens and support the possibility that it is the endogenous ligand of the cGHRH receptor.

  13. Controlled-release systems for the insect growth regulator pyriproxyfen.

    PubMed

    Schwartz, Liliana; Wolf, David; Markus, Arie; Wybraniec, Sławomir; Wiesman, Zeev

    2003-09-24

    A simple technique was developed for the production of controlled-release systems (CRSs) for pyriproxyfen, an insect growth regulator active against the larvae of Culex pipiens, the most common species of mosquito found in developed countries. The CRSs consisted of a spongy core material encapsulated in a coating of a polyurethane or polyurea hydrogel, into which the active ingredient had been incorporated. The coating also included a surfactant to improve the low solubility in water of pyriproxyfen. The light core material enabled the CRS to float on the water surface, where the mosquitoe larvae are found. The type and amount of the polymeric coating and the amount of surfactant influenced the release profiles into water of the active ingredient. The release profiles of the CRSs were adjusted to the life cycle of the C. pipiens mosquito in order to obtain their optimal activity on the eighth day, which corresponds to the time of larval maturity.

  14. Growth and growth factors in diabetes mellitus.

    PubMed Central

    Salardi, S; Tonioli, S; Tassoni, P; Tellarini, M; Mazzanti, L; Cacciari, E

    1987-01-01

    Growth of 79 children with diabetes was analysed at diagnosis and again after one to 10.7 years of treatment with insulin. Both sexes were tall at onset, whereas at the last observation boys alone showed significant growth retardation. Height standard deviation score (SDS), however, showed no significant fall either in 32 subjects reassessed after five years of disease or in 18 subjects examined at full stature. Skeletal maturity was not significantly impaired after treatment. Pubertal growth spurt was reduced, especially in girls and in subjects with onset of disease at or around puberty. We found no significant correlation between height and height velocity SDS and glycosylated haemoglobin values or secretion of growth hormone during the arginine test. Somatomedin C values were correlated with height velocity SDS in prepubertal boys. The results of this study suggest that there are interferences in the growth of children with diabetes but that they do not seem to have a significant influence on adult height. PMID:3813637

  15. Polyethlyene glycol microgels to deliver bioactive nerve growth factor.

    PubMed

    Stukel, Jessica; Thompson, Susan; Simon, Laurent; Willits, Rebecca

    2015-02-01

    Delivery of bioactive molecules is a critical step in fabricating materials for regenerative medicine, yet, this step is particularly challenging in hydrated scaffolds such as hydrogels. Although bulk photocrosslinked poly(ethylene glycol) (PEG) hydrogels have been used for a variety of tissue engineering applications, their capability as drug delivery scaffolds has been limited due to undesirable release profiles and reduction in bioactivity of molecules. To solve these problems, this article presents the fabrication of degradable PEG microgels, which are micron-sized spherical hydrogels, to deliver bioactive nerve growth factor (NGF). NGF release and activity was measured after encapsulation in microgels formed from either 3 kDa or 6 kDa PEG to determine the role of hydrogel mesh size on release. Microgels formed from 6 kDa PEG were statistically larger and had a higher swelling ratio than 3 kDa PEG. The 6 kDa PEG microgels provided a Fickian release with a reduced burst effect and 3 kDa microgels provided anomalous release over ≥20 days. Regardless of molecular weight of PEG, NGF bioactivity was not significantly reduced compared to unprocessed NGF. These results demonstrate that microgels provide easy mechanisms to control the release while retaining the activity of growth factors. As this microgel-based delivery system can be injected at the site of nerve injury to promote nerve repair, the potential to deliver active growth factors in a controlled manner may reduce healing time for neural tissue engineering applications.

  16. Algorithmic complexity of growth hormone release in humans

    SciTech Connect

    Prank, K.; Wagner, M.; Brabant, G.

    1996-12-31

    Most hormones are secreted in an pulsatile rather than in a constant manner. This temporal pattern of pulsatile hormone release plays an important role in the regulation of cellular function and structure. In healthy humans growth hormone (GH) secretion is characterized by distinct pulses whereas patients bearing a GH producing tumor accompanied with excessive secretion (acromegaly) exhibit a highly irregular pattern of GH release. It has been hypothesized that this highly disorderly pattern of GH release in acromegaly arises from random events in the GH-producing tumor under decreased normal control of GH secretion. Using a context-free grammar complexity measure (algorithmic complexity) in conjunction with random surrogate data sets we demonstrate that the temporal pattern of GH release in acromegaly is not significantly different from a variety of stochastic processes. In contrast, normal subjects clearly exhibit deterministic structure in their temporal patterns of GH secretion. Our results support the hypothesis that GH release in acromegaly is due to random events in the GH-producing tumorous cells which might become independent from hypothalamic regulation. 17 refs., 1 fig., 2 tabs.

  17. Enhancement of RNA Polymerase Activity by a Factor Released by Auxin from Plasma Membrane*

    PubMed Central

    Hardin, James W.; Cherry, Joe H.; Morré, D. James; Lembi, Carole A.

    1972-01-01

    Using recently developed techniques for solubilization of RNA polymerase from soybean chromatin and isolation of plasma membrane fractions from plants we can show the presence of a transcriptional factor specifically released from the membranes by auxin, 2,4-dichlorophenoxyacetic acid. The nonauxin, 3,5-dichlorophenoxyacetic acid, does not release the factor, but subsequent exposure of the membranes to auxin results in its release. Factor activity could not be demonstrated in fractions devoid of plasma membranes. The presence of a regulatory factor for RNA polymerase associated with plant plasma membrane and specifically released by auxin provides a mechanism whereby both rapid growth responses and delayed nuclear changes could be derived from a common auxin receptor site associated with plasma membrane. Images PMID:4508307

  18. Growth Factors and Tension-Induced Skeletal Muscle Growth

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman H.

    1994-01-01

    The project investigated biochemical mechanisms to enhance skeletal muscle growth, and developed a computer based mechanical cell stimulator system. The biochemicals investigated in this study were insulin/(Insulin like Growth Factor) IGF-1 and Steroids. In order to analyze which growth factors are essential for stretch-induced muscle growth in vitro, we developed a defined, serum-free medium in which the differentiated, cultured avian muscle fibers could be maintained for extended periods of time. The defined medium (muscle maintenance medium, MM medium) maintains the nitrogen balance of the myofibers for 3 to 7 days, based on myofiber diameter measurements and myosin heavy chain content. Insulin and IGF-1, but not IGF-2, induced pronounced myofiber hypertrophy when added to this medium. In 5 to 7 days, muscle fiber diameters increase by 71 % to 98% compared to untreated controls. Mechanical stimulation of the avian muscle fibers in MM medium increased the sensitivity of the cells to insulin and IGF-1, based on a leftward shift of the insulin dose/response curve for protein synthesis rates. (54). We developed a ligand binding assay for IGF-1 binding proteins and found that the avian skeletal muscle cultures produced three major species of 31, 36 and 43 kD molecular weight (54) Stretch of the myofibers was found to have no significant effect on the efflux of IGF-1 binding proteins, but addition of exogenous collagen stimulated IGF-1 binding protein production 1.5 to 5 fold. Steroid hormones have a profound effect on muscle protein turnover rates in vivo, with the stress-related glucocorticoids inducing rapid skeletal muscle atrophy while androgenic steroids induce skeletal muscle growth. Exercise in humans and animals reduces the catabolic effects of glucocorticoids and may enhance the anabolic effects of androgenic steroids on skeletal muscle. In our continuing work on the involvement of exogenrus growth factors in stretch-induced avian skeletal muscle growth, we

  19. Primary medical therapy for acromegaly: an open, prospective, multicenter study of the effects of subcutaneous and intramuscular slow-release octreotide on growth hormone, insulin-like growth factor-I, and tumor size.

    PubMed

    Bevan, J S; Atkin, S L; Atkinson, A B; Bouloux, P-M; Hanna, F; Harris, P E; James, R A; McConnell, M; Roberts, G A; Scanlon, M F; Stewart, P M; Teasdale, E; Turner, H E; Wass, J A H; Wardlaw, J M

    2002-10-01

    Conventional surgery and radiotherapy for acromegaly have limitations. There are few data on the use of the somatostatin analog octreotide (Oct) as primary medical therapy. An open prospective study of 27 patients with newly diagnosed acromegaly was conducted in nine endocrine centers in the United Kingdom. Twenty patients had macroadenomas, and 7 had microadenomas. For the first 24 wk (phase 1), patients received sc Oct in an initial dose of 100 microg, 3 times daily, increased to 200 micro g three times daily after 4 wk in the 13 patients whose mean serum GH remained greater than 5 mU/liter (2 microg/liter). Five-point GH profiles were performed at 0, 4, 12, and 24 wk, and high resolution pituitary imaging using a standard protocol was performed at 0, 12, and 24 wk (magnetic resonance imaging in 25 patients and computed tomography in 2). Tumor dimensions and volumes were calculated by a central, reporting neuroradiologist, and the results were audited by a second, independent neuroradiologist. After 24 wk, 15 patients proceeded to phase 2 of the study with a direct switch to monthly injections of the depot formulation of Oct, Sandostatin long-acting release (Oct-LAR). Further GH profiles were performed at 36 and 48 wk, and pituitary imaging was performed at 48 wk. The median pretreatment serum GH concentration was 30.7 mU/liter (range, 6.7-141.4). During sc Oct, serum GH fell to less than 5 mU/liter in 9 patients (38%), and IGF-I fell to normal in 8 patients (33%). All 27 tumors shrank during sc Oct; for microadenomas the median tumor volume reduction was 49% (range, 12-73), and for macroadenomas it was 43% (range, 6-92). After 24 wk of Oct-LAR (end of phase 2), the GH level was less than 5 mU/liter in 11 of 14 patients (79%), and IGF-I was normal in 8 of 15 patients (53%). In the 15 patients given Oct-LAR (10 macroadenomas), wk 48 scans showed a further overall median tumor volume reduction of 24%. At the end of the study 79% of patients had mean serum GH levels

  20. Growth factors and cytokines in wound healing.

    PubMed

    Barrientos, Stephan; Stojadinovic, Olivera; Golinko, Michael S; Brem, Harold; Tomic-Canic, Marjana

    2008-01-01

    Wound healing is an evolutionarily conserved, complex, multicellular process that, in skin, aims at barrier restoration. This process involves the coordinated efforts of several cell types including keratinocytes, fibroblasts, endothelial cells, macrophages, and platelets. The migration, infiltration, proliferation, and differentiation of these cells will culminate in an inflammatory response, the formation of new tissue and ultimately wound closure. This complex process is executed and regulated by an equally complex signaling network involving numerous growth factors, cytokines and chemokines. Of particular importance is the epidermal growth factor (EGF) family, transforming growth factor beta (TGF-beta) family, fibroblast growth factor (FGF) family, vascular endothelial growth factor (VEGF), granulocyte macrophage colony stimulating factor (GM-CSF), platelet-derived growth factor (PDGF), connective tissue growth factor (CTGF), interleukin (IL) family, and tumor necrosis factor-alpha family. Currently, patients are treated by three growth factors: PDGF-BB, bFGF, and GM-CSF. Only PDGF-BB has successfully completed randomized clinical trials in the Unites States. With gene therapy now in clinical trial and the discovery of biodegradable polymers, fibrin mesh, and human collagen serving as potential delivery systems other growth factors may soon be available to patients. This review will focus on the specific roles of these growth factors and cytokines during the wound healing process.

  1. Growth Factors in Proliferative Diabetic Retinopathy

    PubMed Central

    Khan, Zia Ali

    2003-01-01

    Many growth factors are implicated in the pathogenesis of proliferative diabetic retinopathy. Alteration of growth factors and their receptors in diabetes has been shown in both experimental and clinical studies. Sustained hyperglycemia resulting from long-standing diabetes leads to several biochemical abnormalities that consequently result in retinal hypoxia. Retinal oxygenation state regulates various growth factors that promote angiogenesis in order to meet the oxygen demands of the tissue. However, unregulated expression of these growth factors and induction of complex cascades leading to augmentation of other proangiogenic factors, which may not be regulated by tissue oxygenation, leads to uncontrolled retinal neovascularization and blindness in diabetic patients. PMID:14668050

  2. Vascular endothelial growth factor and fibroblast growth factor 2 delivery from spinal cord bridges to enhance angiogenesis following injury.

    PubMed

    De Laporte, Laura; des Rieux, Anne; Tuinstra, Hannah M; Zelivyanskaya, Marina L; De Clerck, Nora M; Postnov, Andrei A; Préat, Véronique; Shea, Lonnie D

    2011-09-01

    The host response to spinal cord injury can lead to an ischemic environment that can induce cell death and limits cell transplantation approaches to promote spinal cord regeneration. Spinal cord bridges that provide a localized and sustained release of vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF-2) were investigated for their ability to promote angiogenesis and nerve growth within the injury. Bridges were fabricated by fusion of poly(lactide-co-glycolide) microspheres using a gas foaming/particulate leaching technique, and proteins were incorporated by encapsulation into the microspheres and/or mixing with the microspheres before foaming. Compared to the mixing method, encapsulation reduced the losses during leaching and had a slower protein release, while VEGF was released more rapidly than FGF-2. In vivo implantation of bridges loaded with VEGF enhanced the levels of VEGF within the injury at 1 week, and bridges releasing VEGF and FGF-2 increased the infiltration of endothelial cells and the formation of blood vessel at 6 weeks postimplantation. Additionally, substantial neurofilament staining was observed within the bridge; however, no significant difference was observed between bridges with or without protein. Bridges releasing angiogenic factors may provide an approach to overcome an ischemic environment that limits regeneration and cell transplantation-based approaches.

  3. Myogenic expression of an injectable protease-resistant growth hormone-releasing hormone augments long-term growth in pigs

    NASA Technical Reports Server (NTRS)

    Draghia-Akli, R.; Fiorotto, M. L.; Hill, L. A.; Malone, P. B.; Deaver, D. R.; Schwartz, R. J.

    1999-01-01

    Ectopic expression of a new serum protease-resistant porcine growth hormone-releasing hormone, directed by an injectable muscle-specific synthetic promoter plasmid vector (pSP-HV-GHRH), elicits growth in pigs. A single 10 mg intramuscular injection of pSP-HV-GHRH DNA followed by electroporation in three-week-old piglets elevated serum GHRH levels by twofold to fourfold, enhanced growth hormone secretion, and increased serum insulin-like growth factor-I by threefold to sixfold over control pigs. After 65 days the average body weight of the pigs injected with pSP-HV-GHRH was approximately 37% greater than the placebo-injected controls and resulted in a significant reduction in serum urea concentration, indicating a decrease in amino acid catabolism. Evaluation of body composition indicated a uniform increase in mass, with no organomegaly or associated pathology.

  4. Synthetic heparin-binding growth factor analogs

    DOEpatents

    Pena, Louis A.; Zamora, Paul; Lin, Xinhua; Glass, John D.

    2007-01-23

    The invention provides synthetic heparin-binding growth factor analogs having at least one peptide chain that binds a heparin-binding growth factor receptor, covalently bound to a hydrophobic linker, which is in turn covalently bound to a non-signaling peptide that includes a heparin-binding domain. The synthetic heparin-binding growth factor analogs are useful as soluble biologics or as surface coatings for medical devices.

  5. Research on growth factors in periodontology.

    PubMed

    Smith, Patricio C; Martínez, Constanza; Cáceres, Mónica; Martínez, Jorge

    2015-02-01

    Growth factors play critical roles in periodontal repair through the regulation of cell behavior. Many of the cell responses regulated by these proteins include cell adhesion, migration, proliferation and differentiation. Periodontal regeneration involves an organized response of different cells, tissues and growth factors implicated in the coordination of these events. However, periodontal tissue reconstruction is an extremely difficult task. Multiple studies have been performed to understand the specific role of growth factors in periodontal wound healing. In the present review we analyze the evidence that supports the roles of growth factors in periodontal wound healing and regeneration.

  6. How does the pathophysiological context influence delivery of bone growth factors?☆

    PubMed Central

    Yu, Xiaohua; Suárez-González, Darilis; Khalil, Andrew S.; Murphy, William L.

    2014-01-01

    “Orthobiologics” represents an important category of therapeutics for the regeneration of bone defects caused by injuries or diseases, and bone growth factors are a particularly rapidly growing sub-category. Clinical application of bone growth factors has accelerated in the last two decades with the introduction of BMPs into clinical bone repair. Optimal use of growth factor-mediated treatments heavily relies on controlled delivery, which can substantially influence the local growth factor dose, release kinetics, and biological activity. The characteristics of the surrounding environment, or “context”, during delivery can dictate growth factor loading efficiency, release and biological activity. This review discusses the influence of the surrounding environment on therapeutic delivery of bone growth factors. We specifically focus on pathophysiological components, including soluble components and cells, and how they can actively influence the therapeutic delivery and perhaps efficacy of bone growth factors. PMID:25453269

  7. Growth factor gene therapy for Alzheimer disease.

    PubMed

    Tuszynski, Mark H; U, Hoi Sang; Alksne, John; Bakay, Roy A; Pay, Mary Margaret; Merrill, David; Thal, Leon J

    2002-11-15

    The capacity to prevent neuronal degeneration and death during the course of progressive neurological disorders such as Alzheimer disease (AD) would represent a significant advance in therapy. Nervous system growth factors are families of naturally produced proteins that, in animal models, exhibit extensive potency in preventing neuronal death due to a variety of causes, reversing age-related atrophy of neurons, and ameliorating functional deficits. The main challenge in translating growth factor therapy to the clinic has been delivery of growth factors to the brain in sufficient concentrations to influence neuronal function. One means of achieving growth factor delivery to the central nervous system in a highly targeted, effective manner may be gene therapy. In this article the authors summarize the development and implementation of nerve growth factor gene delivery as a potential means of reducing cell loss in AD.

  8. Heparin-Binding Epidermal Growth Factor-like Growth Factor/Diphtheria Toxin Receptor in Normal and Neoplastic Hematopoiesis

    PubMed Central

    Vinante, Fabrizio; Rigo, Antonella

    2013-01-01

    Heparin-binding EGF-like growth factor (HB-EGF) belongs to the EGF family of growth factors. It is biologically active either as a molecule anchored to the membrane or as a soluble form released by proteolytic cleavage of the extracellular domain. HB-EGF is involved in relevant physiological and pathological processes spanning from proliferation and apoptosis to morphogenesis. We outline here the main activities of HB-EGF in connection with normal or neoplastic differentiative or proliferative events taking place primitively in the hematopoietic microenvironment. PMID:23888518

  9. Growth hormone release induced by growth hormone-releasing hexapeptide is not mediated by thyrotropin-releasing hormone in neonatal rats.

    PubMed

    Kacsóh, B; Kacsóh, G; Guzzardo, M B; Black, A C; Bisat, T

    1997-02-01

    GH-releasing hexapeptide (GHRP-6) and nursing stimulate GH secretion in rat pups via GH-releasing factors (GRFs: distinct from GH-releasing hormone (GHRH). It was determined whether GH secretion induced by GHRP-6 or nursing was mediated by TSH-releasing hormone (TRH) in 2-d-old rats. In vitro. GHRP-6 and TRH stimulated GH secretion of neonatal pituitary glands. At their maximally effective doses, GHRP-6 and TRH evoked approximately equal GH responses. Treatment with a combination of the maximally effective doses of GHRP-6 and TRH resulted in a GH response comparable to that evoked by either treatment alone. GHRP-6 in vivo induced a greater GH response than did TRH. Treatment in vivo with a combination of the maximally effective doses of GHRP-6 and TRH synergistically increased serum GH levels. Unlike GHRP-6 TRH was an effective stimulus of prolactin secretion either in vitro or in vivo. Nursing was an effective stimulus for GH secretion, but only marginally increased serum prolactin levels. The effects of either of the peptides and nursing on GH secretion were additive. These results suggest that GHRP-6 stimulates GH secretion both by acting directly on the pituitary gland and indirectly via a hypothalamic GRF. The indirect effect appears to be greater. The alternative GRFs released by GHRP-6 or nursing are distinct from each other and from TRH. These findings suggest that alternative GRFs play a significant role in the regulation of GH secretion in neonatal rats.

  10. Growth factors from genes to clinical application

    SciTech Connect

    Sara, V.R. ); Hall, K.; Low, H. )

    1990-01-01

    The last decade has witnessed an explosion in the identification of growth factors and their receptors. This has been greatly facilitated by recombinant DNA technology, which has provided the tools not only to identify these proteins at the gene level but also to produce recombinant proteins for evaluating their biological activities. With the help of such techniques, we are moving toward an understanding of the biosynthesis of growth factors and their receptors, structure-function relationships, as well as mechanisms for intracellular signal transmission. The possibility of modifying these factors has opened new fields of clinical application. In this paper, four major areas of growth factor research are presented: the characterization of growth factor genes and their protein products, growth factor receptors and signal transduction by the receptors to mediate biological action, the biological actions of the various growth factors, and the role of growth factors in health and disease and their possible clinical application. Some of the topics covered include: structure of the IGFs and their variants; isoforms of PDGF receptor types; tyrosine kinase activation; structure of G-proteins in biological membranes; possible therapeutic application of NGF in the treatment of Parkinson's and Alzheimer's diseases; PDGF's possible role in the development of several fibroproliferative diseases and its therapeutic application in wound healing; and the possible use of angiogenic inhibitors in tumor treatment.

  11. [Transforming growth factor of beta-type].

    PubMed

    Stoĭka, R S

    1988-01-01

    Recent data about the structure and properties of the beta-type transforming growth factor as well as evidence about its influence on different target cells are presented. The regulatory action of the factor is shown to depend mainly on the type of tested cells, conditions of their culturing and the presence of other bioregulators of cell proliferation in the medium. The prospects of the beta-type transforming growth factor use in practice are considered.

  12. In vitro release study of mono-PEGylated growth hormone-releasing peptide-6 from PLGA microspheres.

    PubMed

    Park, Eun Ji; Na, Dong Hee; Lee, Kang Choon

    2007-10-01

    The purpose of this study was to investigate in vitro release property of mono-PEGylated growth hormone-releasing peptide-6 (GHRP-6) microspheres. The microspheres encapsulating native GHRP-6 or mono-PEG-GHRP-6 were prepared using the single oil-in-water emulsion solvent evaporation method. In vitro release study was performed in 0.1M phosphate buffer, pH 7.4, containing 0.02% Tween 80 and sodium azide at 37 or 55 degrees C. The mono-PEG-GHRP-6 microspheres showed a lower initial burst compared with native GHRP-6 microspheres and zero-order release profile for a 1-month period. The release period was dependent on the PEG size attached to the GHRP-6 with more rapid drug release being observed with the smaller PEG size. This study suggests that PEGylated peptide has good potential as a source for a sustained release microsphere delivery system.

  13. Growth factors for the treatment of ischemic brain injury (growth factor treatment).

    PubMed

    Larpthaveesarp, Amara; Ferriero, Donna M; Gonzalez, Fernando F

    2015-04-30

    In recent years, growth factor therapy has emerged as a potential treatment for ischemic brain injury. The efficacy of therapies that either directly introduce or stimulate local production of growth factors and their receptors in damaged brain tissue has been tested in a multitude of models for different Central Nervous System (CNS) diseases. These growth factors include erythropoietin (EPO), vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF), and insulin-like growth factor (IGF-1), among others. Despite the promise shown in animal models, the particular growth factors that should be used to maximize both brain protection and repair, and the therapeutic critical period, are not well defined. We will review current pre-clinical and clinical evidence for growth factor therapies in treating different causes of brain injury, as well as issues to be addressed prior to application in humans.

  14. Platelet Activating Factor: A Growth Factor for Breast Cancer

    DTIC Science & Technology

    2006-09-01

    Factor for Breast Cancer PRINCIPAL INVESTIGATOR: Larry W. Daniel, Ph.D. CONTRACTING ORGANIZATION: Wake Forest University...A Growth Factor for Breast Cancer 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-04-1-0682 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Larry W...Relevance: If PAF is found to be a growth and angiogenic factor for breast cancer cells, these studies can be followed up by in vivo studies in nude

  15. Growth factor involvement in tension-induced skeletal muscle growth

    NASA Technical Reports Server (NTRS)

    Vandenburgh, H. H.

    1987-01-01

    Muscle tissue culture techniques were developed to grow skeletal myofibers which differentiate into more adult-like myofibers. Mechanical simulation studies of these muscle cells in a newly developed mechanical cell simulator can now be performed to study growth processes in skeletal muscle. Conditions in the mechanical cell simulator were defined where mechanical activity can either prevent muscle wasting or stimulate muscle growth. The role of endogenous and exogenous growth factors in tension-induced muscle growth is being investigated under the defined conditions of tissue culture.

  16. Extracellular matrix-inspired growth factor delivery systems for bone regeneration

    SciTech Connect

    Martino, Mikaël M.; Briquez, Priscilla S.; Maruyama, Kenta; Hubbell, Jeffrey A.

    2015-04-17

    Growth factors are very promising molecules to enhance bone regeneration. However, their translation to clinical use has been seriously limited, facing issues related to safety and cost-effectiveness. These problems derive from the vastly supra-physiological doses of growth factor used without optimized delivery systems. Therefore, these issues have motivated the development of new delivery systems allowing better control of the spatio-temporal release and signaling of growth factors. Because the extracellular matrix (ECM) naturally plays a fundamental role in coordinating growth factor activity in vivo, a number of novel delivery systems have been inspired by the growth factor regulatory function of the ECM. After introducing the role of growth factors during the bone regeneration process, this review exposes different issues that growth factor-based therapies have encountered in the clinic and highlights recent delivery approaches based on the natural interaction between growth factor and the ECM.

  17. Beta hairpin peptide hydrogels as an injectable solid vehicle for neurotrophic growth factor delivery

    PubMed Central

    Lindsey, Stephan; Piatt, Joseph H.; Worthington, Peter; Sönmez, Cem; Satheye, Sameer; Schneider, Joel P.; Pochan, Darrin J.; Langhans, Sigrid A.

    2016-01-01

    There is intense interest in developing novel methods for the sustained delivery of low levels of clinical therapeutics. MAX8 is a peptide-based beta-hairpin hydrogel that has unique shear thinning properties that allow for immediate rehealing after the removal of shear forces, making MAX8 an excellent candidate for injectable drug delivery at a localized injury site. The current studies examined the feasibility of using MAX8 as a delivery system for Nerve Growth Factor (NGF) and Brain-derived neurotrophic factor (BDNF), two neurotrophic growth factors currently used in experimental treatments of spinal cord injuries. Experiments determined that encapsulation of NGF and BDNF within MAX8 did not negatively impact gel formation or rehealing and that shear thinning did not result in immediate growth factor release. We found that increased NGF/BDNF dosages increased the amount and rate of growth factor release and that NGF/BDNF release was inversely related to the concentration of MAX8, indicating that growth factor release can be tuned by adjusting MAX8 concentrations. Encapsulation within MAX8 protected NGF and BDNF from in vitro degradation for up to 28 days. Released NGF resulted in the formation of neurite-like extensions in PC12 pheochromocytoma cells, demonstrating that NGF remains biologically active after release from encapsulation. Direct physical contact of PC12 cells with NGF-containing hydrogel did not inhibit neurite-like extension formation. On a molecular level, encapsulated growth factors activated the NGF/BDNF signaling pathways. Taken together, our data show MAX8 acts as a time-release gel, continually releasing low levels of growth factor over 21 days. MAX8 allows for greater dosage control and sustained therapeutic growth factor delivery, potentially alleviating side effects and improving the efficacy of current therapies. PMID:26225909

  18. Studies on the biological effects of ozone: 10. Release of factors from ozonated human platelets.

    PubMed

    Valacchi, G; Bocci, V

    1999-01-01

    In a previous work we have shown that heparin, in the presence of ozone (O3), promotes a dose-dependent platelet aggregation, while after Ca2+ chelation with citrate, platelet aggregation is almost negligible. These results led us to think that aggregation may enhance the release of platelet components. We have here shown that indeed significantly higher amount of platelet-derived growth factor (PDGF), transforming growth factor beta1 (TGF-beta1) and interleukin-8 (IL-8) are released in a dose-dependent manner after ozonation of heparinised platelet-rich plasma samples. These findings may explain the enhanced healing of torpid ulcers in patients with chronic limb ischemia treated with O3 autohaemoteraphy (O3-AHT).

  19. Studies on the biological effects of ozone: 10. Release of factors from ozonated human platelets.

    PubMed Central

    Valacchi, G; Bocci, V

    1999-01-01

    In a previous work we have shown that heparin, in the presence of ozone (O3), promotes a dose-dependent platelet aggregation, while after Ca2+ chelation with citrate, platelet aggregation is almost negligible. These results led us to think that aggregation may enhance the release of platelet components. We have here shown that indeed significantly higher amount of platelet-derived growth factor (PDGF), transforming growth factor beta1 (TGF-beta1) and interleukin-8 (IL-8) are released in a dose-dependent manner after ozonation of heparinised platelet-rich plasma samples. These findings may explain the enhanced healing of torpid ulcers in patients with chronic limb ischemia treated with O3 autohaemoteraphy (O3-AHT). PMID:10704074

  20. An unnatural PIP simulates growth factor signaling.

    PubMed

    Swan, Laura

    2009-11-25

    In this issue of Chemistry & Biology, Laketa et al. describe the synthesis of a membrane permeant phosphoinositide lipid that acts to stimulate PI(3,4,5)P(3)-dependent signaling without the need of growth factor stimulation.

  1. New Clue Found to Growth Factor Action.

    ERIC Educational Resources Information Center

    Hoffman, Michelle

    1991-01-01

    Discussed is the discovery which may help to explain epidermal growth factor effects on the cell skeleton. The role of a protein called profilin in the regulation of the microfilament system is described. (CW)

  2. Control of transforming growth factor-beta activity: latency vs. activation.

    PubMed

    Harpel, J G; Metz, C N; Kojima, S; Rifkin, D B

    1992-01-01

    Transforming growth factor-beta is a pluripotent regulator of cell growth and differentiation. The growth factor is expressed as a latent complex that must be converted to an active form before interacting with its ubiquitous high affinity receptors. This conversion involves the release of the mature growth factor through disruption of the non-covalent interactions with its pro-peptide or latency associated peptide. The mechanisms for this release in vivo have not been fully characterized but appear to be cell specific and might involve processes such as acidification or proteolysis. Although several factors including transcriptional regulation, receptor modulation and scavenging of the active growth factor have been implicated, the critical step controlling the biological effects of transforming growth factor-beta may be the activation of the latent molecule.

  3. The role of fibroblast growth factors in tumor growth.

    PubMed

    Korc, M; Friesel, R E

    2009-08-01

    Biological processes that drive cell growth are exciting targets for cancer therapy. The fibroblast growth factor (FGF) signaling network plays a ubiquitous role in normal cell growth, survival, differentiation, and angiogenesis, but has also been implicated in tumor development. Elucidation of the roles and relationships within the diverse FGF family and of their links to tumor growth and progression will be critical in designing new drug therapies to target FGF receptor (FGFR) pathways. Recent studies have shown that FGF can act synergistically with vascular endothelial growth factor (VEGF) to amplify tumor angiogenesis, highlighting that targeting of both the FGF and VEGF pathways may be more efficient in suppressing tumor growth and angiogenesis than targeting either factor alone. In addition, through inducing tumor cell survival, FGF has the potential to overcome chemotherapy resistance highlighting that chemotherapy may be more effective when used in combination with FGF inhibitor therapy. Furthermore, FGFRs have variable activity in promoting angiogenesis, with the FGFR-1 subgroup being associated with tumor progression and the FGFR-2 subgroup being associated with either early tumor development or decreased tumor progression. This review highlights the growing knowledge of FGFs in tumor cell growth and survival, including an overview of FGF intracellular signaling pathways, the role of FGFs in angiogenesis, patterns of FGF and FGFR expression in various tumor types, and the role of FGFs in tumor progression.

  4. Antagonists of growth hormone-releasing hormone suppress in vivo tumor growth and gene expression in triple negative breast cancers.

    PubMed

    Perez, Roberto; Schally, Andrew V; Vidaurre, Irving; Rincon, Ricardo; Block, Norman L; Rick, Ferenc G

    2012-09-01

    This study evaluated the effects of a modern antagonistic analog of GHRH on tumor growth and on expression of inflammatory cytokine genes in two models of human triple negative breast cancers (TNBC). The TNBC subtype is refractory to the treatment options available for other hormone-independent breast cancers. Inflammatory cytokines play a major role in the cellular signaling associated with breast cancer pathogenesis and enhance epithelial-mesenchymal transitions (EMT), drug resistance, and metastatic potential. Growth hormone-releasing hormone (GHRH) is a hypothalamic neuropeptide which regulates the synthesis and release of growth hormone by the pituitary and is an autocrine/paracrine growth factor for multiple human cancers. The effects of analogs of GHRH on tumoral cytokine expression have not been previously investigated. Animals bearing xenografts of the human TNBC cell lines, HCC1806 and MX-1, were treated with MIA-602, an antagonistic analog of GHRH. Treatment with MIA-602 significantly reduced tumor growth. We quantified transcript levels of the genes for several inflammatory cytokines. Expression of INFγ, IL-1α, IL-4, IL-6, IL-8, IL-10, and TNFα, was significantly reduced by treatment with MIA-602. We conclude that treatment of TNBC with GHRH antagonists reduces tumor growth through an action mediated by tumoral GHRH receptors and produces a suppression of inflammatory cytokine signaling. Silencing of GHRH receptors in vitro with siRNA inhibited the expression of GHRH-R genes and inflammatory cytokine genes in HCC1806 and MX-1 cells. Further studies on GHRH antagonists may facilitate the development of new strategies for the treatment of resistant cancers.

  5. The function of vascular endothelial growth factor.

    PubMed

    Nieves, Bonnie J; D'Amore, Patricia A; Bryan, Brad A

    2009-01-01

    Vascular endothelial growth factor (VEGF) is considered the master regulator of angiogenesis during growth and development, as well as in disease states such as cancer, diabetes, and macular degeneration. This review details our current understanding of VEGF signaling and discusses the benefits and unexpected side effects of promising anti-angiogenic therapeutics that are currently being used to inhibit neovacularization in tumors.

  6. Cancer cells. 3: Growth factors and transformation

    SciTech Connect

    Feramisco, J.; Ozanne, B.; Stiles, C.

    1985-01-01

    This book contains over 50 papers. Some of the titles are: Structure of Human Epidermal Growth Factor and Expression of Normal and Variant mRNAs in Epdermoid Carcinoma Cells; Tyrosine Kinase Activity Associated with the v-erb-B Gene Product; Cloning and Characterization of Human Epidermal Growth Factor-Receptor Gene Sequences in A431 Carcinoma Cells; Anti-oncogenes and the Suppression of Tumor Formation; and Normal Human sis/PDGF-2 Gene Expression Induces Cellular Transformation.

  7. Interactions of release factor RF3 with the translation machinery.

    PubMed

    O'Connor, Michael

    2015-08-01

    The bacterial release factor RF3 is a GTPase that has been implicated in multiple, incompletely understood steps of protein synthesis. This study explores the genetic interaction of RF3 with other components of the translation machinery. RF3 contributes to translation termination by recycling the class I release factors RF1 and RF2 off post-termination ribosomes. RF3 has also been implicated in dissociation of peptidyl-tRNAs from elongating ribosomes and in a post-peptidyltransferase quality control (post-PT QC) mechanism that selectively terminates ribosomes carrying erroneous peptides. A majority of the in vivo studies on RF3 have been carried out in K-12 strains of Escherichia coli which carry a partially defective RF2 protein with an Ala to Thr substitution at position 246. Here, the contribution of the K-12 specific RF2 variant to RF3 activities has been investigated. Strain reconstruction experiments in both E. coli and Salmonella enterica demonstrate that defects in termination and post-PT QC that are associated with RF3 loss, as well as phenotypes uncovered by phenotypic profiling, are all substantially ameliorated when the incompletely active K-12-specific RF2 protein is replaced by a fully active Ala246 RF2. These results indicate that RF3 loss is well tolerated in bacteria with fully active class I release factors, but that many of the previously reported phenotypes for RF3 deletion strains have been compromised by the presence of a partially defective RF2.

  8. Insulin-like growth factor 1 and hair growth.

    PubMed

    Su, H Y; Hickford, J G; Bickerstaffe, R; Palmer, B R

    1999-11-01

    Insulin-like growth factor 1 (IGF-1) has been identified as an important growth factor in many biological systems.[1] It shares considerable structural homology with insulin and exerts insulin-like effects on food intake and glucose metabolism. Recently it has been suggested to play a role in regulating cellular proliferation and migration during the development of hair follicles. [2,3] To exert its biological effects, the IGF-1 is required to activate cells by binding to specific cell-surface receptors. The type I IGF receptor (IGF-1R) is the only IGF receptor to have IGF-mediated signaling functions.[1] In circulation, this growth factor mediates endocrine action of growth hormone (GH) on somatic growth and is bound to specific binding proteins (BPs). The latter control IGF transport, efflux from vascular compartments and association with cell surface receptors.[4] In tissues, IGF-1 is produced by mesenchymal type cells and acts in a paracrine and autocrine fashion by binding to the IGF-1R. This binding activates the receptor tyrosine kinase (RTK) that triggers the downstream responses and finally stimulates cell division.[5] IGF-1 may therefore be able to stimulate the proliferation of hair follicle cells through cellular signaling pathways of its receptors. Local infusion of IGF-1 into sheep has been reported to be capable of stimulating protein synthesis in the skin.[6] It may also increase the production of wool keratin. Recently, transgenic mice overexpressing IGF-1 in the skin have been shown to have earlier hair follicle development than controls.[7] In addition, this growth factor plays an important role in many cell types as a survival factor to prevent cell death.[8] This anti-apoptotic function of IGF-1 may be important to the development of follicle cells as follicles undergo a growth cycle where the regressive, catagen phase is apoptosis driven. In this review, the effects of IGF-1 on follicle cell proliferation and differentiation are discussed. In

  9. Drosophila factor 2, an RNA polymerase II transcript release factor, has DNA-dependent ATPase activity.

    PubMed

    Xie, Z; Price, D

    1997-12-12

    Drosophila factor 2 has been identified as a component of negative transcription elongation factor (N-TEF) that causes the release of RNA polymerase II transcripts in an ATP-dependent manner (Xie, Z. and Price D. H. (1996) J. Biol. Chem. 271, 11043-11046). We show here that the transcript release activity of factor 2 requires ATP or dATP and that adenosine 5'-O-(thiotriphosphate) (ATPgammaS), adenosine 5'-(beta,gamma-imino)triphosphate (AMP-PNP), or other NTPs do not support the activity. Factor 2 demonstrated a strong DNA-dependent ATPase activity that correlated with its transcript release activity. At 20 microg/ml DNA, the ATPase activity of factor 2 had an apparent Km(ATP) of 28 microM and an estimated Kcat of 140 min-1. Factor 2 caused the release of nascent transcripts associated with elongation complexes generated by RNA polymerase II on a dC-tailed template. Therefore, no other protein cofactors are required for the transcript release activity of factor 2. Using the dC-tailed template assay, it was found that renaturation of the template was required for factor 2 function.

  10. Role of Corticotropin-releasing Factor in Gastrointestinal Permeability

    PubMed Central

    Rodiño-Janeiro, Bruno K; Alonso-Cotoner, Carmen; Pigrau, Marc; Lobo, Beatriz; Vicario, María; Santos, Javier

    2015-01-01

    The interface between the intestinal lumen and the mucosa is the location where the majority of ingested immunogenic particles face the scrutiny of the vast gastrointestinal immune system. Upon regular physiological conditions, the intestinal micro-flora and the epithelial barrier are well prepared to process daily a huge amount of food-derived antigens and non-immunogenic particles. Similarly, they are ready to prevent environmental toxins and microbial antigens to penetrate further and interact with the mucosal-associated immune system. These functions promote the development of proper immune responses and oral tolerance and prevent disease and inflammation. Brain-gut axis structures participate in the processing and execution of response signals to external and internal stimuli. The brain-gut axis integrates local and distant regulatory networks and super-systems that serve key housekeeping physiological functions including the balanced functioning of the intestinal barrier. Disturbance of the brain-gut axis may induce intestinal barrier dysfunction, increasing the risk of uncontrolled immunological reactions, which may indeed trigger transient mucosal inflammation and gut disease. There is a large body of evidence indicating that stress, through the brain-gut axis, may cause intestinal barrier dysfunction, mainly via the systemic and peripheral release of corticotropin-releasing factor. In this review, we describe the role of stress and corticotropin-releasing factor in the regulation of gastrointestinal permeability, and discuss the link to both health and pathological conditions. PMID:25537677

  11. Material-mediated proangiogenic factor release pattern modulates quality of regenerated blood vessels.

    PubMed

    Rich, Max H; Lee, Min Kyung; Baek, Kwanghyun; Jeong, Jae Hyun; Kim, Dong Hyun; Millet, Larry J; Bashir, Rashid; Kong, Hyunjoon

    2014-12-28

    Hydrogels designed to sustainably release bioactive molecules are extensively used to enhance tissue repair and regenerative therapies. Along this line, numerous efforts are made to control the molecular release rate and amount. In contrast, few efforts are made to control the molecular release pattern, and, subsequently, modulate the spatial organization of newly forming tissues, including blood vessels. Therefore, using a hydrogel printed to release vascular endothelial growth factor (VEGF) into a pre-defined pattern, this study demonstrates that spatial distribution of VEGF is important in guiding growth direction of new blood vessels, and also in retaining the structural integrity of pre-existing vasculature. Guided by a computational model, we fabricated a patch composed of micro-sized VEGF-releasing poly(ethylene glycol) diacrylate (PEGDA) hydrogel cylinders using an ink-jet printer. Interestingly, hydrogel printed with computationally optimized spacing created anisotropically aligned vasculature exclusively when the printed gel pattern was placed parallel to pre-existing blood vessels. In contrast, vascular sprouting from placing the printed gel pattern perpendicular to pre-existing vessels resulted in deformation and structural disintegration of the original vasculature. We envision that this study will be useful to better understand angiogenesis-modulated neovascularization and further improve the treatment quality for various wounds and tissue defects.

  12. Novel systems for tailored neurotrophic factor release based on hydrogel and resorbable glass hollow fibers.

    PubMed

    Novajra, G; Tonda-Turo, C; Vitale-Brovarone, C; Ciardelli, G; Geuna, S; Raimondo, S

    2014-03-01

    A novel system for the release of neurotrophic factor into a nerve guidance channel (NGC) based on resorbable phosphate glass hollow fibers (50P2O5-30CaO-9Na2O-3SiO2-3MgO-2.5K2O-2.5TiO2 mol%) in combination with a genipin-crosslinked agar/gelatin hydrogel (A/G_GP) is proposed. No negative effect on the growth of neonatal olfactory bulb ensheathing cell line (NOBEC) as well as on the expression of pro- and anti-apoptotic proteins was measured in vitro in the presence of fiber dissolution products in the culture medium. For the release studies, fluorescein isothiocyanate-dextran (FD-20), taken as growth factor model molecule, was solubilized in different media and introduced into the fiber lumen exploiting the capillary action. The fibers were filled with i) FD-20/phosphate buffered saline (PBS) solution, ii) FD-20/hydrogel solution before gelation and iii) hydrogel before gelation, subsequently lyophilized and then filled with the FD-20/PBS solution. The different strategies used for the loading of the FD-20 into the fibers resulted in different release kinetics. A slower release was observed with the use of A/G_GP hydrogel. At last, poly(ε-caprolactone) (PCL) nerve guides containing the hollow fibers and the hydrogel have been fabricated.

  13. Engineering growth factors for regenerative medicine applications.

    SciTech Connect

    Mitchell, Aaron C.; Briquez, Priscilla S.; Hubbell, Jeffrey A.; Cochran, Jennifer R.

    2016-01-15

    Growth factors are important morphogenetic proteins that instruct cell behavior and guide tissue repair and renewal. Although their therapeutic potential holds great promise in regenerative medicine applications, translation of growth factors into clinical treatments has been hindered by limitations including poor protein stability, low recombinant expression yield, and suboptimal efficacy. This review highlights current tools, technologies, and approaches to design integrated and effective growth factor-based therapies for regenerative medicine applications. The first section describes rational and combinatorial protein engineering approaches that have been utilized to improve growth factor stability, expression yield, biodistribution, and serum half-life, or alter their cell trafficking behavior or receptor binding affinity. The second section highlights elegant biomaterial-based systems, inspired by the natural extracellular matrix milieu, that have been developed for effective spatial and temporal delivery of growth factors to cell surface receptors. Although appearing distinct, these two approaches are highly complementary and involve principles of molecular design and engineering to be considered in parallel when developing optimal materials for clinical applications.

  14. Placenta Growth Factor in Diabetic Wound Healing

    PubMed Central

    Cianfarani, Francesca; Zambruno, Giovanna; Brogelli, Laura; Sera, Francesco; Lacal, Pedro Miguel; Pesce, Maurizio; Capogrossi, Maurizio C.; Failla, Cristina Maria; Napolitano, Monica; Odorisio, Teresa

    2006-01-01

    Reduced microcirculation and diminished expression of growth factors contribute to wound healing impairment in diabetes. Placenta growth factor (PlGF), an angiogenic mediator promoting pathophysiological neovascularization, is expressed during cutaneous wound healing and improves wound closure by enhancing angiogenesis. By using streptozotocin-induced diabetic mice, we here demonstrate that PlGF induction is strongly reduced in diabetic wounds. Diabetic transgenic mice overexpressing PlGF in the skin displayed accelerated wound closure compared with diabetic wild-type littermates. Moreover, diabetic wound treatment with an adenovirus vector expressing the human PlGF gene (AdCMV.PlGF) significantly accelerated the healing process compared with wounds treated with a control vector. The analysis of treated wounds showed that PlGF gene transfer improved granulation tissue formation, maturation, and vascularization, as well as monocytes/macrophages local recruitment. Platelet-derived growth factor, fibroblast growth factor-2, and vascular endothelial growth factor mRNA levels were increased in AdCMV.PlGF-treated wounds, possibly enhancing PlGF-mediated effects. Finally, PlGF treatment stimulated cultured dermal fibroblast migration, pointing to a direct role of PlGF in accelerating granulation tissue maturation. In conclusion, our data indicate that reduced PlGF expression contributes to impaired wound healing in diabetes and that PlGF gene transfer to diabetic wounds exerts therapeutic activity by promoting different aspects of the repair process. PMID:17003476

  15. Platelet quantification and growth factor analysis from platelet-rich plasma: implications for wound healing.

    PubMed

    Eppley, Barry L; Woodell, Jennifer E; Higgins, Joel

    2004-11-01

    Growth factors released from activated platelets initiate and modulate wound healing in both soft and hard tissues. A recent strategy to promote the wound-healing cascade is to prepare an autologous platelet concentrate suspended in plasma, also known as platelet-rich plasma, that contains growth factors and administer it to wound sites. The purpose of this study was to quantitate platelet number and growth factors released from a prepared platelet concentrate. Whole blood was drawn from 10 healthy patients undergoing cosmetic surgery and concentrated into platelet-rich plasma. Platelet counts on whole blood and platelet-rich plasma were determined using a Cell-Dyn 3200. Platelet-derived growth factor-BB, transforming growth factor-beta1, vascular endothelial growth factor, endothelial growth factor, and insulin-like growth factor-1 were measured in the platelet-rich plasma using the enzyme-linked immunosorbent assay method. In addition, platelet activation during the concentration procedure was analyzed by measuring P selectin values in blood serum. An 8-fold increase in platelet concentration was found in the platelet-rich plasma compared with that of whole blood (baseline whole blood, 197 +/- 42 x 10 platelets/microl; platelet concentrate, 1600 +/- 330 x 10 platelets/microl). The concentration of growth factors also increased with increasing platelet number. However, growth factor concentration varied from patient to patient. On average for the whole blood as compared with platelet-rich plasma, the platelet-derived growth factor-BB concentration increased from 3.3 +/- 0.9 ng/ml to 17 +/- 8 ng/ml, transforming growth factor-beta1 concentration increased from 35 +/- 8 ng/ml to 120 +/- 42 ng/ml, vascular endothelial growth factor concentration increased from 155 +/- 110 pg/ml to 955 +/- 1030 pg/ml, and endothelial growth factor concentration increased from 129 +/- 61 pg/ml to 470 +/- 320 pg/ml. No increase was found for insulin-like growth factor-1. In addition, no

  16. Delivery of Alginate Scaffold Releasing Two Trophic Factors for Spinal Cord Injury Repair

    PubMed Central

    Grulova, I.; Slovinska, L.; Blaško, J.; Devaux, S.; Wisztorski, M.; Salzet, M.; Fournier, I.; Kryukov, O.; Cohen, S.; Cizkova, D.

    2015-01-01

    Spinal cord injury (SCI) has been implicated in neural cell loss and consequently functional motor and sensory impairment. In this study, we propose an alginate -based neurobridge enriched with/without trophic growth factors (GFs) that can be utilized as a therapeutic approach for spinal cord repair. The bioavailability of key GFs, such as Epidermal Growth factor (EGF) and basic Fibroblast Growth Factor (bFGF) released from injected alginate biomaterial to the central lesion site significantly enhanced the sparing of spinal cord tissue and increased the number of surviving neurons (choline acetyltransferase positive motoneurons) and sensory fibres. In addition, we document enhanced outgrowth of corticospinal tract axons and presence of blood vessels at the central lesion. Tissue proteomics was performed at 3, 7 and 10 days after SCI in rats indicated the presence of anti-inflammatory factors in segments above the central lesion site, whereas in segments below, neurite outgrowth factors, inflammatory cytokines and chondroitin sulfate proteoglycan of the lectican protein family were overexpressed. Collectively, based on our data, we confirm that functional recovery was significantly improved in SCI groups receiving alginate scaffold with affinity-bound growth factors (ALG +GFs), compared to SCI animals without biomaterial treatment. PMID:26348665

  17. PROSPECT - GROWTH FACTOR CONTROL OF BONE MASS

    PubMed Central

    Canalis, Ernesto

    2010-01-01

    Bone formation is determined by the number and function of osteoblasts. Cell number is governed by factors that regulate the replication and differentiation of pre-osteoblasts and factors that regulate osteoblastic cell death. Cell function is controlled by signals acting on the mature osteoblast. Platelet derived and fibroblast growth factors are bone cell mitogens. Bone morphogenetic proteins (BMP) and Wnt induce the differentiation of mesenchymal cells toward osteoblasts, and insulin-like growth factor (IGF)-I stimulates the function of mature osteoblasts and prevents their death. The activity of BMP, Wnt and IGF-I is modulated by extracellular antagonists or binding proteins. Changes in growth factor synthesis and activity may play a role in the pathogenesis of selected forms of osteoporosis, and alterations in the expression or binding of the extracellular antagonists can be associated with changes in bone mass. Current approaches to bone anabolic therapies for osteoporosis include the administration of a growth factor, such as IGF-I, or the neutralization of an antagonist. Ideally, the targeting of an anabolic agent should be specific to bone to preclude non-skeletal unwanted side effects. Clinical trials are needed to determine the long-term effectiveness and safety of novel anabolic agents for the management of osteoporosis. PMID:19718659

  18. Neuropeptide W stimulates adrenocorticotrophic hormone release via corticotrophin-releasing factor but not via arginine vasopressin.

    PubMed

    Yogo, Kosuke; Oki, Yutaka; Iino, Kazumi; Yamashita, Miho; Shibata, Shoko; Hayashi, Chiga; Sasaki, Shigekazu; Suenaga, Toshiko; Nakahara, Daiichiro; Nakamura, Hirotoshi

    2012-01-01

    Neuropeptide W (NPW) was isolated as an endogenous ligand for NPBWR1, an orphan G protein-coupled receptor localized in the rat brain, including the paraventricular nucleus. It has been reported that central administration of NPW stimulates corticosterone secretion in rats. We hypothesized that NPW activates the hypothalamic-pituitary-adrenal (HPA) axis via corticotrophin-releasing factor (CRF) and/or arginine vasopressin (AVP). NPW at 1 pM to 10 nM did not affect basal or ACTH-induced corticosterone release from dispersed rat adrenocortical cells, or basal and CRF-induced ACTH release from dispersed rat anterior pituitary cells. In conscious and unrestrained male rats, intravenous administration of 2.5 and 25 nmol NPW did not affect plasma ACTH levels. However, intracerebroventricular (icv) administration of 2.5 and 5.0 nmol NPW increased plasma ACTH levels in a dose-dependent manner at 15 min after stimulation (5.0 vs. 2.5 nmol NPW vs. vehicle: 1802 ± 349 vs. 1170 ± 204 vs. 151 ± 28 pg/mL, respectively, mean ± SEM). Pretreatment with astressin, a CRF receptor antagonist, inhibited the increase in plasma ACTH levels induced by icv administration of 2.5 nmol NPW at 15 min (453 ± 176 vs. 1532 ± 343 pg/mL, p<0.05) and at 30 min (564 ± 147 vs. 1214 ± 139 pg/mL, p<0.05) versus pretreatment with vehicle alone. However, pretreatment with [1-(β-mercapto-β, β-cyclopentamethylenepropionic acid), 2-(Ο-methyl)tyrosine]-arg-vasopressin, a V1a/V1b receptor antagonist, did not affect icv NPW-induced ACTH release at any time (p>0.05). In conclusion, we suggest that central NPW activates the HPA axis by activating hypothalamic CRF but not AVP.

  19. Effect of Deletion of Ghrelin-O-Acyltransferase on the Pulsatile Release of Growth Hormone in Mice.

    PubMed

    Xie, T Y; Ngo, S T; Veldhuis, J D; Jeffery, P L; Chopin, L K; Tschöp, M; Waters, M J; Tolle, V; Epelbaum, J; Chen, C; Steyn, F J

    2015-12-01

    Ghrelin, a gut hormone originating from the post-translational cleavage of preproghrelin, is the endogenous ligand of growth hormone secretagogue receptor 1a (GHS-R1a). Within the growth hormone (GH) axis, the biological activity of ghrelin requires octanoylation by ghrelin-O-acyltransferase (GOAT), conferring selective binding to the GHS-R1a receptor via acylated ghrelin. Complete loss of preproghrelin-derived signalling (through deletion of the Ghrl gene) contributes to a decline in peak GH release; however, the selective contribution of endogenous acyl-ghrelin to pulsatile GH release remains to be established. We assessed the pulsatile release of GH in ad lib. fed male germline goat(-/-) mice, extending measures to include mRNA for key hypothalamic regulators of GH release, and peripheral factors that are modulated relative to GH release. The amount of GH released was reduced in young goat(-/-) mice compared to age-matched wild-type mice, whereas pulse frequency and irregularity increased. Altered GH release did not coincide with alterations in hypothalamic Ghrh, Srif, Npy or Ghsr mRNA expression, or pituitary GH content, suggesting that loss of Goat does not compromise canonical mechanisms that contribute to pituitary GH production and release. Although loss of Goat resulted in an irregular pattern of GH release (characterised by an increase in the number of GH pulses observed during extended secretory events), this did not contribute to a change in the expression of sexually dimorphic GH-dependent liver genes. Of interest, circulating levels of insulin-like growth factor (IGF)-1 were elevated in goat(-/-) mice. This rise in circulating levels of IGF-1 was correlated with an increase in GH pulse frequency, suggesting that sustained or increased IGF-1 release in goat(-/-) mice may occur in response to altered GH release patterning. Our observations demonstrate that germline loss of Goat alters GH release and patterning. Although the biological relevance of

  20. Puberty, statural growth, and growth hormone release in children with cerebral palsy

    PubMed Central

    Kuperminc, Michelle N.; Gurka, Matthew J.; Houlihan, Christine M.; Henderson, Richard C.; Roemmich, James N.; Rogol, Alan D.

    2010-01-01

    Objective Children with cerebral palsy (CP) are smaller than normally growing children.. The association between the growth hormone (GH) axis and growth in children with CP during puberty is unknown. We compared growth and markers of the GH axis in pre-pubertal and pubertal children with moderate to severe CP and without CP over a three-year period. Study design Twenty children with CP, ages 6–18, Gross Motor Function Classification System levels III–V, were compared to a group of sixty-three normally growing children of similar age. Anthropometry, Tanner stage, bone age, and laboratory analyses were performed every six months for three years. Laboratory values included spontaneous overnight GH release, fasting IGF-1 and IGFBP-3. Repeated measures models were used to evaluate interactions among Tanner stage and group (children with CP vs. reference children), taking into account gender, age, and nutritional status. Results Children with CP grew more slowly than those without CP at all Tanner stages (p<0.01). Patterns of IGF-1 and GH secretion in children with CP were similar to those of the reference group; however, the concentrations of IGF-1 (p<0.01) and GH (p<0.01) were lower in girls with CP, with a similar trend for boys (p=0.10 and 0.14, respectively). Conclusions Diminished circulating IGF-1 and GH concentrations may explain the differences in growth between the two groups. PMID:20216931

  1. Growth hormone-releasing peptide-6 inhibits cerebellar cell death in aged rats.

    PubMed

    Pañeda, Covadonga; Arroba, Ana I; Frago, Laura M; Holm, Anne Mette; Rømer, John; Argente, Jesús; Chowen, Julie A

    2003-08-26

    Insulin-like growth factor (IGF)-I is essential for cerebellar granule neuron survival and a decline in IGF-I is implicated in various age-dependent processes. Here we show that IGF-I mRNA levels are decreased in the cerebellum of old rats compared with young rats and this was associated with increased cell death and activation of caspases 3 and 9. Growth hormone-releasing peptide (GHRP)-6, a synthetic ligand for the ghrelin receptor, increased IGF-I mRNA levels, decreased cell death and inhibited caspase 3 and 9 activation in the cerebellum of aged rats. These results suggest that increasing IGF-I expression in the cerebellum can decrease cell death in aged rats via inhibition of caspase 3 and 9 activation.

  2. Therapeutic potential of growth factors and their antagonists.

    PubMed Central

    Garner, A.

    1992-01-01

    This article describes studies with four peptides, epidermal growth factor (EGF), transforming growth factor alpha (TGF alpha), gastrin-releasing peptide/bombesin (GRP), and gastrin. The mitogenic and anti-secretory activities of EGF/TGF alpha appear to be mediated by a single class of high-affinity membrane receptors but may involve different signal transducing mechanisms. Biological activity of EGF resides in the N-terminal 42 amino acid fragment with the C-terminal undecapeptide determining binding affinity. A parenteral depot formulation of an EGF-related peptide or a small molecule agonist of the EGF receptor could have utility in treating various ulcerative disorders of the gut. Although antagonism of EGF (and thus TGF alpha) receptors and/or transducing mechanisms is frequently cited as a potential therapeutic approach to hyperproliferative diseases, blocking the action of TGF alpha, GRP, or gastrin with neutralizing antibodies or receptor antagonists did not influence the growth of a wide range of solid tumors in nude mice. These findings suggest that, unless tumor growth displays absolute dependency on one particular mitogen, antagonism of a specific growth factor is unlikely to have great effect in cancer therapy. PMID:1341074

  3. Placental Growth Factor Administration Abolishes Placental Ischemia-Induced Hypertension.

    PubMed

    Spradley, Frank T; Tan, Adelene Y; Joo, Woo S; Daniels, Garrett; Kussie, Paul; Karumanchi, S Ananth; Granger, Joey P

    2016-04-01

    Preeclampsia is a pregnancy-specific disorder of new-onset hypertension. Unfortunately, the most effective treatment is early delivery of the fetus and placenta. Placental ischemia appears central to the pathogenesis of preeclampsia because placental ischemia/hypoxia induced in animals by reduced uterine perfusion pressure (RUPP) or in humans stimulates release of hypertensive placental factors into the maternal circulation. The anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes and reduces bioavailable vascular endothelial growth factor and placental growth factor (PlGF), is elevated in RUPP rats and preeclampsia. Although PlGF and vascular endothelial growth factor are both natural ligands for sFlt-1, vascular endothelial growth factor also has high affinity to VEGFR2 (Flk-1) causing side effects like edema. PlGF is specific for sFlt-1. We tested the hypothesis that PlGF treatment reduces placental ischemia-induced hypertension by antagonizing sFlt-1 without adverse consequences to the mother or fetus. On gestational day 14, rats were randomized to 4 groups: normal pregnant or RUPP±infusion of recombinant human PlGF (180 μg/kg per day; AG31, a purified, recombinant human form of PlGF) for 5 days via intraperitoneal osmotic minipumps. On day 19, mean arterial blood pressure and plasma sFlt-1 were higher and glomerular filtration rate lower in RUPP than normal pregnant rats. Infusion of recombinant human PlGF abolished these changes seen with RUPP along with reducing oxidative stress. These data indicate that the increased sFlt-1 and reduced PlGF resulting from placental ischemia contribute to maternal hypertension. Our novel finding that recombinant human PlGF abolishes placental ischemia-induced hypertension, without major adverse consequences, suggests a strong therapeutic potential for this growth factor in preeclampsia.

  4. Mesoporous bioactive glass scaffolds for efficient delivery of vascular endothelial growth factor.

    PubMed

    Wu, Chengtie; Fan, Wei; Chang, Jiang; Xiao, Yin

    2013-09-01

    In this article, we, for the first time, investigated mesoporous bioactive glass scaffolds for the delivery of vascular endothelial growth factor. We have found that mesoporous bioactive glass scaffolds have significantly higher loading efficiency and more sustained release of vascular endothelial growth factor than non-mesoporous bioactive glass scaffolds. In addition, vascular endothelial growth factor delivery from mesoporous bioactive glass scaffolds has improved the viability of endothelial cells. The study has suggested that mesopore structures in mesoporous bioactive glass scaffolds play an important role in improving the loading efficiency, decreasing the burst release, and maintaining the bioactivity of vascular endothelial growth factor, indicating that mesoporous bioactive glass scaffolds are an excellent carrier of vascular endothelial growth factor for potential bone tissue engineering applications.

  5. Epidermal Growth Factor and Intestinal Barrier Function

    PubMed Central

    Liu, Hu; Yang, Shufen; Li, Zuohua; Zhong, Jinfeng

    2016-01-01

    Epidermal growth factor (EGF) is a 53-amino acid peptide that plays an important role in regulating cell growth, survival, migration, apoptosis, proliferation, and differentiation. In addition, EGF has been established to be an effective intestinal regulator helping to protect intestinal barrier integrity, which was essential for the absorption of nutrients and health in humans and animals. Several researches have demonstrated that EGF via binding to the EGF receptor and subsequent activation of Ras/MAPK, PI3K/AKT, PLC-γ/PKC, and STATS signal pathways regulates intestinal barrier function. In this review, the relationship between epidermal growth factor and intestinal development and intestinal barrier is described, to provide a better understanding of the effects of EGF on intestine development and health. PMID:27524860

  6. Immobilization and Application of Electrospun Nanofiber Scaffold-based Growth Factor in Bone Tissue Engineering.

    PubMed

    Chen, Guobao; Lv, Yonggang

    2015-01-01

    Electrospun nanofibers have been extensively used in growth factor delivery and regenerative medicine due to many advantages including large surface area to volume ratio, high porosity, excellent loading capacity, ease of access and cost effectiveness. Their relatively large surface area is helpful for cell adhesion and growth factor loading, while storage and release of growth factor are essential to guide cellular behaviors and tissue formation and organization. In bone tissue engineering, growth factors are expected to transmit signals that stimulate cellular proliferation, migration, differentiation, metabolism, apoptosis and extracellular matrix (ECM) deposition. Bolus administration is not always an effective method for the delivery of growth factors because of their rapid diffusion from the target site and quick deactivation. Therefore, the integration of controlled release strategy within electrospun nanofibers can provide protection for growth factors against in vivo degradation, and can manipulate desired signal at an effective level with extended duration in local microenvironment to support tissue regeneration and repair which normally takes a much longer time. In this review, we provide an overview of growth factor delivery using biomimetic electrospun nanofiber scaffolds in bone tissue engineering. It begins with a brief introduction of different kinds of polymers that were used in electrospinning and their applications in bone tissue engineering. The review further focuses on the nanofiber-based growth factor delivery and summarizes the strategies of growth factors loading on the nanofiber scaffolds for bone tissue engineering applications. The perspectives on future challenges in this area are also pointed out.

  7. Incisional wound healing in transforming growth factor-beta1 null mice.

    PubMed

    Koch, R M; Roche, N S; Parks, W T; Ashcroft, G S; Letterio, J J; Roberts, A B

    2000-01-01

    Expression of endogenous transforming growth factor-beta1 is reduced in many animal models of impaired wound healing, and addition of exogenous transforming growth factor-beta has been shown to improve healing. To test the hypothesis that endogenous transforming growth factor-beta1 is essential for normal wound repair, we have studied wound healing in mice in which the transforming growth factor-beta1 gene has been deleted by homologous recombination. No perceptible differences were observed in wounds made in 3-10-day-old neonatal transforming growth factor-beta1 null mice compared to wild-type littermates. To preclude interference from maternally transferred transforming growth factor-beta1, cutaneous wounds were also made on the backs of 30-day-old transforming growth factor-beta1 null and littermate control mice treated with rapamycin, which extends their lifetime and suppresses the inflammatory response characteristic of the transforming growth factor-beta1 null mice. Again, no impairment in healing was seen in transforming growth factor-beta1 null mice. Instead these wounds showed an overall reduction in the amount of granulation tissue and an increased rate of epithelialization compared to littermate controls. Our data suggest that release of transforming growth factor-beta1 from degranulating platelets or secretion by infiltrating macrophages and fibroblasts is not critical to initiation or progression of tissue repair and that endogenous transforming growth factor-beta1 may actually function to increase inflammation and retard wound closure.

  8. A Review of Bioactive Release from Nerve Conduits as a Neurotherapeutic Strategy for Neuronal Growth in Peripheral Nerve Injury

    PubMed Central

    Choonara, Yahya E.; Bijukumar, Divya; du Toit, Lisa C.

    2014-01-01

    Peripheral nerve regeneration strategies employ the use of polymeric engineered nerve conduits encompassed with components of a delivery system. This allows for the controlled and sustained release of neurotrophic growth factors for the enhancement of the innate regenerative capacity of the injured nerves. This review article focuses on the delivery of neurotrophic factors (NTFs) and the importance of the parameters that control release kinetics in the delivery of optimal quantities of NTFs for improved therapeutic effect and prevention of dose dumping. Studies utilizing various controlled-release strategies, in attempt to obtain ideal release kinetics, have been reviewed in this paper. Release strategies discussed include affinity-based models, crosslinking techniques, and layer-by-layer technologies. Currently available synthetic hollow nerve conduits, an alternative to the nerve autografts, have proven to be successful in the bridging and regeneration of primarily the short transected nerve gaps in several patient cases. However, current research emphasizes on the development of more advanced nerve conduits able to simulate the effectiveness of the autograft which includes, in particular, the ability to deliver growth factors. PMID:25143934

  9. Conserved motifs in prokaryotic and eukaryotic polypeptide release factors: tRNA-protein mimicry hypothesis.

    PubMed Central

    Ito, K; Ebihara, K; Uno, M; Nakamura, Y

    1996-01-01

    Translation termination requires two codon-specific polypeptide release factors in prokaryotes and one omnipotent factor in eukaryotes. Sequences of 17 different polypeptide release factors from prokaryotes and eukaryotes were compared. The prokaryotic release factors share residues split into seven motifs. Conservation of many discrete, perhaps critical, amino acids is observed in eukaryotic release factors, as well as in the C-terminal portion of elongation factor (EF) G. Given that the C-terminal domains of EF-G interacts with ribosomes by mimicry of a tRNA structure, the pattern of conservation of residues in release factors may reflect requirements for a tRNA-mimicry for binding to the A site of the ribosome. This mimicry would explain why release factors recognize stop codons and suggests that all prokaryotic and eukaryotic release factors evolved from the progenitor of EF-G. Images Fig. 2 Fig. 3 PMID:8643594

  10. Transforming growth factor (TGF)-. alpha. in human milk

    SciTech Connect

    Okada, Masaki; Wakai, Kae; Shizume, Kazuo ); Iwashita, Mitsutoshi ); Ohmura, Eiji; Kamiya, Yoshinobu; Murakami, Hitomi; Onoda, Noritaka; Tsushima, Toshio

    1991-01-01

    Transforming growth factor (TGF)-{alpha} and epidermal growth factor (EGF) were measured in human milk by means of homologous radioimmunoassay. As previously reported, EGF concentration in the colostrum was approximately 200 ng/ml and decreased to 50 ng/ml by day 7 postpartum. The value of immunoreactive (IR)-TGF-{alpha} was 2.2-7.2 ng/ml, much lower than that of EGF. In contrast to EGF, the concentration of IR-TGF-{alpha} was fairly stable during the 7 postpartum days. There was no relationship between the concentrations of IR-TGF-{alpha} and IR-EGF, suggesting that the regulatory mechanism in the release of the two growth factors is different. On gel-chromatography using a Sephadex G-50 column, IR-EGF appeared in the fraction corresponding to that of authentic human EGF, while 70%-80% of the IR-TGF-{alpha} was eluted as a species with a molecular weight greater than that of authentic human TGF-{alpha}. Although the physiological role of TGF-{alpha} in milk is not known, it is possible that it is involved in the development of the mammary gland and/or the growth of newborn infants.

  11. Intrahypothalamic neuroendocrine actions of corticotropin-releasing factor.

    PubMed

    Almeida, O F; Hassan, A H; Holsboer, F

    1993-01-01

    Most studies of the neuroendocrine effects of corticotropin-releasing factor (CRF) have focused on its role in the regulation of the pituitary-adrenal axis; activation of this axis follows release of the peptide from CRF-containing terminals in the median eminence. However, a sizeable proportion of CRF fibres terminate within the hypothalamus itself, where synaptic contacts with other hypothalamic neuropeptidergic neurons (e.g. gonadotropin-releasing hormone-containing and opioidergic neurons) have been identified. Here, we summarize physiological and pharmacological data which provide insights into the nature and significance of these intrahypothalamic connections. It is now clear that CRF is a potent secretagogue of the three major endogenous opioid peptides (beta-endorphin, Met-enkephalin and dynorphin) and that it stimulates opioidergic neurons tonically. In the case of beta-endorphin, another hypothalamic peptide, arginine vasopressin, appears to be an essential mediator of CRF's effect, suggesting the occurrence of CRF synapses on, or in the vicinity of, vasopressin neurons; morphological support for this assumption is still wanting. Evidence for direct and indirect inhibitory effects of CRF on sexual behaviour and secretion of reproductive hormones is also presented; the indirect pathways include opioidergic neurons. An important conclusion from all these studies is that, in addition to its better known functions in producing adaptive responses during stressful situations, CRF might also contribute to the coordinated functioning of various components of the neuroendocrine system under basal conditions. Although feedback regulation of hypothalamic neuronal activity by peripheral steroids is a well-established tenet of endocrinology, data on modulation of the intrahypothalamic actions of CRF by adrenal and sex steroids are just emerging. Some of these newer findings may be useful in framing questions related to the mechanisms underlying disease states (such as

  12. Nerve Growth Factor and Diabetic Neuropathy

    PubMed Central

    Vinik, Aaron

    2003-01-01

    Neuropathy is one of the most debilitating complications of both type 1 and type 2 diabetes, with estimates of prevalence between 50–90% depending on the means of detection. Diabetic neuropathies are heterogeneous and there is variable involvement of large myelinated fibers and small, thinly myelinated fibers. Many of the neuronal abnormalities in diabetes can be duplicated by experimental depletion of specific neurotrophic factors, their receptors or their binding proteins. In experimental models of diabetes there is a reduction in the availability of these growth factors, which may be a consequence of metabolic abnormalities, or may be independent of glycemic control. These neurotrophic factors are required for the maintenance of the neurons, the ability to resist apoptosis and regenerative capacity. The best studied of the neurotrophic factors is nerve growth factor (NGF) and the related members of the neurotrophin family of peptides. There is increasing evidence that there is a deficiency of NGF in diabetes, as well as the dependent neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) that may also contribute to the clinical symptoms resulting from small fiber dysfunction. Similarly, NT3 appears to be important for large fiber and IGFs for autonomic neuropathy. Whether the observed growth factor deficiencies are due to decreased synthesis, or functional, e.g. an inability to bind to their receptor, and/or abnormalities in nerve transport and processing, remains to be established. Although early studies in humans on the role of neurotrophic factors as a therapy for diabetic neuropathy have been unsuccessful, newer agents and the possibilities uncovered by further studies should fuel clinical trials for several generations. It seems reasonable to anticipate that neurotrophic factor therapy, specifically targeted at different nerve fiber populations, might enter the therapeutic armamentarium. PMID:14668049

  13. Enhanced basal and disorderly growth hormone secretion distinguish acromegalic from normal pulsatile growth hormone release.

    PubMed Central

    Hartman, M L; Pincus, S M; Johnson, M L; Matthews, D H; Faunt, L M; Vance, M L; Thorner, M O; Veldhuis, J D

    1994-01-01

    Pulses of growth hormone (GH) release in acromegaly may arise from hypothalamic regulation or from random events intrinsic to adenomatous tissue. To distinguish between these possibilities, serum GH concentrations were measured at 5-min intervals for 24 h in acromegalic men and women with active (n = 19) and inactive (n = 9) disease and in normal young adults in the fed (n = 20) and fasted (n = 16) states. Daily GH secretion rates, calculated by deconvolution analysis, were greater in patients with active acromegaly than in fed (P < 0.05) but not fasted normal subjects. Significant basal (nonpulsatile) GH secretion was present in virtually all active acromegalics but not those in remission or in fed and fasted normal subjects. A recently introduced scale- and model-independent statistic, approximate entropy (ApEn), was used to test for regularity (orderliness) in the GH data. All but one acromegalic had ApEn values greater than the absolute range in normal subjects, indicating reduced orderliness of GH release; ApEn distinguished acromegalic from normal GH secretion (fed, P < 10(-12); fasted, P < 10(-7)) with high sensitivity (95%) and specificity (100%). Acromegalics in remission had ApEn scores larger than those of normal subjects (P < 0.0001) but smaller than those of active acromegalics (P < 0.001). The coefficient of variation of successive incremental changes in GH concentrations was significantly lower in acromegalics than in normal subjects (P < 0.001). Fourier analysis in acromegalics revealed reduced fractional amplitudes compared to normal subjects (P < 0.05). We conclude that GH secretion in acromegaly is highly irregular with disorderly release accompanying significant basal secretion. Images PMID:8083369

  14. Transforming growth factor alpha and epidermal growth factor levels in bladder cancer and their relationship to epidermal growth factor receptor.

    PubMed Central

    Mellon, J. K.; Cook, S.; Chambers, P.; Neal, D. E.

    1996-01-01

    We have examined levels of epidermal growth factor (EGF) and transforming growth factor alpha (TGF-alpha) in neoplastic and non-neoplastic bladder tissue using a standard radioimmunoassay technique. Tumour samples had much higher TGF-alpha levels compared with EGF and TGF-alpha levels in malignant tissue were significantly higher than in benign bladder samples. There was, in addition, a difference in mean EGF levels from 'normal' bladder samples from non-tumour bearing areas of bladder in patients with bladder cancer compared with 'normal' bladder tissue obtained at the time of organ retrieval surgery. Levels of EGF and TGF-alpha did not correlate with levels of EGF receptor (EGFR) as determined by a radioligand binding method but levels of TGF-alpha > 10 ng gm-1 of tumour tissue did correlate with EGFR positivity defined using immunohistochemistry. These data suggest that TGF-alpha is the likely ligand for EGFR in bladder tumours. PMID:8605103

  15. E2F1 transcription factor and its impact on growth factor and cytokine signaling.

    PubMed

    Ertosun, Mustafa Gokhan; Hapil, Fatma Zehra; Osman Nidai, Ozes

    2016-10-01

    E2F1 is a transcription factor involved in cell cycle regulation and apoptosis. The transactivation capacity of E2F1 is regulated by pRb. In its hypophosphorylated form, pRb binds and inactivates DNA binding and transactivating functions of E2F1. The growth factor stimulation of cells leads to activation of CDKs (cyclin dependent kinases), which in turn phosphorylate Rb and hyperphosphorylated Rb is released from E2F1 or E2F1/DP complex, and free E2F1 can induce transcription of several genes involved in cell cycle entry, induction or inhibition of apoptosis. Thus, growth factors and cytokines generally utilize E2F1 to direct cells to either fate. Furthermore, E2F1 regulates expressions of various cytokines and growth factor receptors, establishing positive or negative feedback mechanisms. This review focuses on the relationship between E2F1 transcription factor and cytokines (IL-1, IL-2, IL-3, IL-6, TGF-beta, G-CSF, LIF), growth factors (EGF, KGF, VEGF, IGF, FGF, PDGF, HGF, NGF), and interferons (IFN-α, IFN-β and IFN-γ).

  16. Sugarcane transgenics expressing MYB transcription factors show improved glucose release

    DOE PAGES

    Poovaiah, Charleson R.; Bewg, William P.; Lan, Wu; ...

    2016-07-15

    In this study, sugarcane, a tropical C4 perennial crop, is capable of producing 30-100 tons or more of biomass per hectare annually. The lignocellulosic residue remaining after sugar extraction is currently underutilized and can provide a significant source of biomass for the production of second-generation bioethanol. As a result, MYB31 and MYB42 were cloned from maize and expressed in sugarcane with and without the UTR sequences. The cloned sequences were 98 and 99 % identical to the published nucleotide sequences. The inclusion of the UTR sequences did not affect any of the parameters tested. There was little difference in plantmore » height and the number of internodes of the MYB-overexpressing sugarcane plants when compared with controls. MYB transgene expression determined by qPCR exhibited continued expression in young and maturing internodes. MYB31 downregulated more genes within the lignin biosynthetic pathway than MYB42. MYB31 and MYB42 expression resulted in decreased lignin content in some lines. All MYB42 plants further analyzed showed significant increases in glucose release by enzymatic hydrolysis in 72 h, whereas only two MYB31 plants released more glucose than control plants. This correlated directly with a significant decrease in acid-insoluble lignin. Soluble sucrose content of the MYB42 transgenic plants did not vary compared to control plants. In conclusion, this study demonstrates the use of MYB transcription factors to improve the production of bioethanol from sugarcane bagasse remaining after sugar extraction.« less

  17. The effects of control release fertilizer (CRF) on palm growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutri-Pak is a slow release fertilizer in a micro-pore polyethylene packet where moisture enters the packet through micro-pores located on both sides of the packet. Water dissolves the fertilizer and it slowly seeps through the same micro-pores as a vapor into the soil gradually providing nutrients ...

  18. Progress in corticotropin-releasing factor-1 antagonist development

    PubMed Central

    Zorrilla, Eric P.; Koob, George F.

    2010-01-01

    Corticotropin-releasing factor (CRF) receptor antagonists have been sought since the stress-secreted peptide was isolated in 1981. Although evidence suggests the limited efficacy of CRF1 antagonists as antidepressants, CRF1 antagonists might be novel pharmacotherapies for anxiety and addiction. Progress in understanding the two-domain model of ligand–receptor interactions for CRF family receptors might yield chemically novel CRF1 receptor antagonists, including peptide CRF1 antagonists, antagonists with signal transduction selectivity and nonpeptide CRF1 antagonists that act via the extracellular (rather than transmembrane) domains. Novel ligands that conform to prevalent pharmacophore and exhibit drug-like pharmacokinetic properties have been identified. The therapeutic utility of CRF1 antagonists should soon be clearer: several small molecules are currently in Phase II/III clinical trials for depression, anxiety and irritable bowel syndrome. PMID:20206287

  19. Growth factor expression in degenerated intervertebral disc tissue. An immunohistochemical analysis of transforming growth factor beta, fibroblast growth factor and platelet-derived growth factor.

    PubMed

    Tolonen, Jukka; Grönblad, Mats; Vanharanta, Heikki; Virri, Johanna; Guyer, Richard D; Rytömaa, Tapio; Karaharju, Erkki O

    2006-05-01

    Degenerated intervertebral disc has lost its normal architecture, and there are changes both in the nuclear and annular parts of the disc. Changes in cell shape, especially in the annulus fibrosus, have been reported. During degeneration the cells become more rounded, chondrocyte-like, whereas in the normal condition annular cells are more spindle shaped. These chondrocyte-like cells, often forming clusters, affect extracellular matrix turnover. In previous studies transforming growth factor beta (TGFbeta) -1 and -2, basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) have been highlighted in herniated intervertebral disc tissue. In the present study the same growth factors are analysed immunohistochemically in degenerated intervertebral disc tissue. Disc material was obtained from 16 discs operated for painful degenerative disc disease. Discs were classified according to the Dallas Discogram Description. Different disc regions were analysed in parallel. As normal control disc tissue material from eight organ donors was used. Polyclonal antibodies against different growth factors and TGFbeta receptor type II were used, and the immunoreaction was detected by the avidin biotin complex method. All studied degenerated discs showed immunoreactivity for TGFbeta receptor type II and bFGF. Fifteen of 16 discs were immunopositive for TGFbeta-1 and -2, respectively, and none showed immunoreaction for PDGF. Immunopositivity was located in blood vessels and in disc cells. In the nucleus pulposus the immunoreaction was located almost exclusively in chondrocyte-like disc cells, whereas in the annular region this reaction was either in chondrocyte-like disc cells, often forming clusters, or in fibroblast-like disc cells. Chondrocyte-like disc cells were especially prevalent in the posterior disrupted area. In the anterior area of the annulus fibrosus the distribution was more even between these two cell types. bFGF was expressed in the anterior annulus

  20. Corticotropin releasing factor stimulates cAMP formation in pituitary corticotropic tumor cells

    SciTech Connect

    Parenti, M.; Cantalamessa, L.; Catania, A.; Reschini, E.; Mueller, E.E.

    1984-01-23

    Addition of corticotropin-releasing factor (CRF) to membranes from two ACTH-secreting pituitary tumors strikingly increased in a dose-dependent fashion adenylate cyclase (AC) activity. Stimulation of AC activity by CRF in membranes from non-tumoral tissue adjacent to tumoral corticotrophs was considerably lower, and was lacking in membranes from a growth hormone secreting tumor. These data correlated well with in vivo pre-surgery and post-surgery ACTH responsiveness to CRF of the tumor bearing patients. Basal AC activity was higher in pituitary adenomas than in non-tumoral adjacent tissue.

  1. Sugarcane transgenics expressing MYB transcription factors show improved glucose release

    SciTech Connect

    Poovaiah, Charleson R.; Bewg, William P.; Lan, Wu; Ralph, John; Coleman, Heather D.

    2016-07-15

    In this study, sugarcane, a tropical C4 perennial crop, is capable of producing 30-100 tons or more of biomass per hectare annually. The lignocellulosic residue remaining after sugar extraction is currently underutilized and can provide a significant source of biomass for the production of second-generation bioethanol. As a result, MYB31 and MYB42 were cloned from maize and expressed in sugarcane with and without the UTR sequences. The cloned sequences were 98 and 99 % identical to the published nucleotide sequences. The inclusion of the UTR sequences did not affect any of the parameters tested. There was little difference in plant height and the number of internodes of the MYB-overexpressing sugarcane plants when compared with controls. MYB transgene expression determined by qPCR exhibited continued expression in young and maturing internodes. MYB31 downregulated more genes within the lignin biosynthetic pathway than MYB42. MYB31 and MYB42 expression resulted in decreased lignin content in some lines. All MYB42 plants further analyzed showed significant increases in glucose release by enzymatic hydrolysis in 72 h, whereas only two MYB31 plants released more glucose than control plants. This correlated directly with a significant decrease in acid-insoluble lignin. Soluble sucrose content of the MYB42 transgenic plants did not vary compared to control plants. In conclusion, this study demonstrates the use of MYB transcription factors to improve the production of bioethanol from sugarcane bagasse remaining after sugar extraction.

  2. Effects of hypothalamic dopamine on growth hormone-releasing hormone-induced growth hormone secretion and thyrotropin-releasing hormone-induced prolactin secretion in goats.

    PubMed

    Jin, Jin; Hashizume, Tsutomu

    2015-06-01

    The aim of the present study was to clarify the effects of hypothalamic dopamine (DA) on the secretion of growth hormone (GH) in goats. The GH-releasing response to an intravenous (i.v.) injection of GH-releasing hormone (GHRH, 0.25 μg/kg body weight (BW)) was examined after treatments to augment central DA using carbidopa (carbi, 1 mg/kg BW) and L-dopa (1 mg/kg BW) in male and female goats under a 16-h photoperiod (16 h light, 8 h dark) condition. GHRH significantly and rapidly stimulated the release of GH after its i.v. administration to goats (P < 0.05). The carbi and L-dopa treatments completely suppressed GH-releasing responses to GHRH in both male and female goats (P < 0.05). The prolactin (PRL)-releasing response to an i.v. injection of thyrotropin-releasing hormone (TRH, 1 μg/kg BW) was additionally examined in male goats in this study to confirm modifications to central DA concentrations. The treatments with carbi and L-dopa significantly reduced TRH-induced PRL release in goats (P < 0.05). These results demonstrated that hypothalamic DA was involved in the regulatory mechanisms of GH, as well as PRL secretion in goats.

  3. Heparin-binding epidermal growth factor-like growth factor/diphtheria toxin receptor expression by acute myeloid leukemia cells.

    PubMed

    Vinante, F; Rigo, A; Papini, E; Cassatella, M A; Pizzolo, G

    1999-03-01

    Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is an EGF family member expressed by numerous cell types that binds to EGF receptor 1 (HER-1) or 4 (HER-4) inducing mitogenic and/or chemotactic activities. Membrane-bound HB-EGF retains growth activity and adhesion capabilities and the unique property of being the receptor for diphtheria toxin (DT). The interest in studying HB-EGF in acute leukemia stems from these mitogenic, chemotactic, and receptor functions. We analyzed the expression of HB-EGF in L428, Raji, Jurkat, Karpas 299, L540, 2C8, HL-60, U937, THP-1, ML-3, and K562 cell lines and in primary blasts from 12 acute myeloid leukemia (AML) cases, by reverse-transcriptase polymerase chain reaction (RT-PCR) and Northern blot and by the evaluation of sensitivity to DT. The release of functional HB-EGF was assessed by evaluation of its proliferative effects on the HB-EGF-sensitive Balb/c 3T3 cell line. HB-EGF was expressed by all myeloid and T, but not B (L428, Raji), lymphoid cell lines tested, as well as by the majority (8 of 12) of ex vivo AML blasts. Cell lines (except for the K562 cell line) and AML blasts expressing HB-EGF mRNA underwent apoptotic death following exposure to DT, thus demonstrating the presence of the HB-EGF molecule on their membrane. Leukemic cells also released a fully functional HB-EGF molecule that was mitogenic for the Balb/c 3T3 cell line. Factors relevant to the biology of leukemic growth, such as tumor necrosis factor-alpha (TNF-alpha), 1alpha,25-(OH)2D3, and especially all-trans retinoic acid (ATRA), upregulated HB-EGF mRNA in HL-60 or ML-3 cells. Granulocyte-macrophage colony-stimulating factor (GM-CSF) induced HB-EGF mRNA and acquisition of sensitivity to DT in one previously HB-EGF-negative leukemia case. Moreover, the U937 and Karpas 299 cell lines expressed HER-4 mRNA. This work shows that HB-EGF is a growth factor produced by primary leukemic cells and regulated by ATRA, 1alpha, 25-(OH)2D3, and GM-CSF.

  4. Differential involvement of signaling pathways in the regulation of growth hormone release by somatostatin and growth hormone-releasing hormone in orange-spotted grouper (Epinephelus coioides).

    PubMed

    Wang, Bin; Qin, Chaobin; Zhang, Cong; Jia, Jirong; Sun, Caiyun; Li, Wensheng

    2014-02-15

    Somatostatin is the most effective inhibitor of GH release, and GHRH was recently identified as one of the primary GH-releasing factors in teleosts. In this study, we analyzed the possible intracellular transduction pathways that are involved in the mechanisms induced by SRIF and GHRH to regulate GH release. Using a pharmacological approach, the blockade of the PLC/IP/PKC pathway reversed the SRIF-induced inhibition of GH release but did not affect the GHRH-induced stimulation of GH release. Furthermore, SRIF reduced the GH release induced by two PKC activators. Inhibitors of the AC/cAMP/PKA pathway reversed both the SRIF- and GHRH-induced effects on GH release. Moreover, the GH release evoked by forskolin and 8-Br-cAMP were completely abolished by SRIF. The blockade of the NOS/NO pathway attenuated the GHRH-induced GH release but had minimal effects on the inhibitory actions of SRIF. In addition, inhibitors of the sGC/cGMP pathway did not modify the SRIF- or GHRH-induced regulation of GH release. Taken together, these findings indicate that the SRIF-induced inhibition of GH release is mediated by both the PLC/IP/PKC and the AC/cAMP/PKA pathways and not by the NOS/NO/sGC/cGMP pathway. In contrast, the GHRH-induced stimulation of GH secretion is mediated by both the AC/cAMP/PKA and the NOS/NO pathways and is independent of the sGC/cGMP pathway and the PLC/IP/PKC system.

  5. Insulin-like growth factor 1: common mediator of multiple enterotrophic hormones and growth factors

    PubMed Central

    Bortvedt, Sarah F.; Lund, P. Kay

    2013-01-01

    Purpose of review To summarize recent evidence that IGF1 mediates growth effects of multiple trophic factors and discuss clinical relevance. Recent findings Recent reviews and original reports indicate benefits of growth hormone (GH) and long-acting glucagon-like peptide 2 (GLP2) analogues in short bowel syndrome and Crohn’s disease. This review highlights evidence that biomarkers of sustained small intestinal growth or mucosal healing and evaluation of intestinal epithelial stem cell biomarkers may improve clinical measures of intestinal growth or response to trophic hormones. Compelling evidence that IGF1 mediates growth effects of GH and GLP2 on intestine or linear growth in preclinical models of resection or Crohn’s disease is presented, along with a concept that these hormones or IGF1 may enhance sustained growth if given early after bowel resection. Evidence that SOCS protein induction by GH or GLP2 in normal or inflamed intestine, may limit IGF1-induced growth, but protect against risk of dysplasia or fibrosis is reviewed. Whether IGF1 receptor mediates IGF1 action and potential roles of insulin receptors are addressed. Summary IGF1 has a central role in mediating trophic hormone action in small intestine. Better understanding of benefits and risks of IGF1, receptors that mediate IGF1 action, and factors that limit undesirable growth are needed. PMID:22241077

  6. Proteolytic Processing Regulates Placental Growth Factor Activities*

    PubMed Central

    Hoffmann, Daniel C.; Willenborg, Sebastian; Koch, Manuel; Zwolanek, Daniela; Müller, Stefan; Becker, Ann-Kathrin A.; Metzger, Stephanie; Ehrbar, Martin; Kurschat, Peter; Hellmich, Martin; Hubbell, Jeffrey A.; Eming, Sabine A.

    2013-01-01

    Placental growth factor (PlGF) is a critical mediator of blood vessel formation, yet mechanisms of its action and regulation are incompletely understood. Here we demonstrate that proteolytic processing regulates the biological activity of PlGF. Specifically, we show that plasmin processing of PlGF-2 yields a protease-resistant core fragment comprising the vascular endothelial growth factor receptor-1 binding site but lacking the carboxyl-terminal domain encoding the heparin-binding domain and an 8-amino acid peptide encoded by exon 7. We have identified plasmin cleavage sites, generated a truncated PlGF118 isoform mimicking plasmin-processed PlGF, and explored its biological function in comparison with that of PlGF-1 and -2. The angiogenic responses induced by the diverse PlGF forms were distinct. Whereas PlGF-2 increased endothelial cell chemotaxis, vascular sprouting, and granulation tissue formation upon skin injury, these activities were abrogated following plasmin digestion. Investigation of PlGF/Neuropilin-1 binding and function suggests a critical role for heparin-binding domain/Neuropilin-1 interaction and its regulation by plasmin processing. Collectively, here we provide new mechanistic insights into the regulation of PlGF-2/Neuropilin-1-mediated tissue vascularization and growth. PMID:23645683

  7. Flavonoids Released Naturally from Alfalfa Seeds Enhance Growth Rate of Rhizobium meliloti1

    PubMed Central

    Hartwig, Ueli A.; Joseph, Cecillia M.; Phillips, Donald A.

    1991-01-01

    Alfalfa (Medicago sativa L.) releases different flavonoids from seeds and roots. Imbibing seeds discharge 3′,4′,5,7-substituted flavonoids; roots exude 5-deoxy molecules. Many, but not all, of these flavonoids induce nodulation (nod) genes in Rhizobium meliloti. The dominant flavonoid released from alfalfa seeds is identified here as quercetin-3-O-galactoside, a molecule that does not induce nod genes. Low concentrations (1-10 micromolar) of this compound, as well as luteolin-7-O-glucoside, another major flavonoid released from germinating seeds, and the aglycones, quercetin and luteolin, increase growth rate of R. meliloti in a defined minimal medium. Tests show that the 5,7-dihydroxyl substitution pattern on those molecules was primarily responsible for the growth effect, thus explaining how 5-deoxy flavonoids in root exudates fail to enhance growth of R. meliloti. Luteolin increases growth by a mechanism separate from its capacity to induce rhizobial nod genes, because it still enhanced growth rate of R. meliloti lacking functional copies of the three known nodD genes. Quercetin and luteolin also increased growth rate of Pseudomonas putida. They had no effect on growth rate of Bacillus subtilis or Agrobacterium tumefaciens, but they slowed growth of two fungal pathogens of alfalfa. These results suggest that alfalfa can create ecochemical zones for controlling soil microbes by releasing structurally different flavonoids from seeds and roots. PMID:16668056

  8. Root growth in response to nitrogen supply in Chinese maize hybrids released between 1973 and 2009.

    PubMed

    Wu, QiuPing; Chen, FanJun; Chen, YanLing; Yuan, LiXing; Zhang, FuSuo; Mi, GuoHua

    2011-07-01

    Root growth has a fundamental role in nitrogen (N) use efficiency. Nevertheless, little is known about how modern breeding progress has affected root growth and its responses to N supply. The root and shoot growth of a core set of 11 representative Chinese maize (Zea mays L.) hybrids released between 1973 and 2009 were investigated under high N (4 mmol L(-1), HN) and low N (0.04 mmol L(-1), LN) levels in a solution culture system. Compared with LN, HN treatment decreased root dry weight (RDW), the root: shoot ratio (R/S), and the relative growth rate for root dry weight (RGR(root)), but increased the total root length (TRL) and the total lateral root length (LRL). The total axial root length (ARL) per plant was reduced under HN, mostly in hybrids released before the 1990s. The number of seminal roots (SRN) was largely unaffected by different N levels. More recently released hybrids showed higher relative growth rates in the shoot under both HN and LN. However, the roots only showed increased RGR under HN treatment. Correspondingly, there was a positive linear relationship with the year of hybrid release for TRL, LRL and ARL under HN treatment. Together, these results suggest that while shoot growth of maize has improved, its root growth has only improved under high N conditions over the last 36 years of selective breeding in China. Improving root growth under LN conditions may be necessary to increase the N use efficiency of maize.

  9. The role of transforming growth factor-beta, insulin-like growth factor I, and basic fibroblast growth factor in distraction osteogenesis of the mandible.

    PubMed

    Farhadieh, R D; Dickinson, R; Yu, Y; Gianoutsos, M P; Walsh, W R

    1999-01-01

    Distraction osteogenesis is a viable method for regenerating large amounts of bone. In contrast to fracture healing, the mode of bone formation in distraction osteogenesis is primarily intramembranous ossification. The basic biology of the process is still not well understood. The growth factor cascade is likely to play an important role in distraction. This study examines the growth factor cascade in a lengthened ovine mandible model. Twenty-four animals were divided into four groups with varying rates of distraction (1, 2, 3, and 4 mm/day). A unilateral distractor at the angle of the mandible was used. The mandibles were lengthened to 24 mm and fixed for a period of 5 weeks, after which the animals were killed. The sections were probed for transforming growth factor-beta, basic fibroblast growth factor, and insulin-like growth factor I. The growth factors studied were present in all four groups. Transforming growth factor-beta, basic fibroblast growth factor, and insulin-like growth factor I were present in both the bony matrix of the sections and the cytoplasm of the cells, osteoblasts, and a small number of mesenchymal cells. The sections obtained from groups distracted at faster rates showed stronger presence of the growth factors examined by more intense staining. In fracture healing, the localization of transforming growth factor-beta in stage I of healing corresponded with the precise region of intramembranous ossification in stage II. Diffuse presence of transforming growth factor-beta throughout the lengthened region corresponded with the process of intramembranous ossification observed in distraction. In fracture healing, insulin-like growth factor I and basic fibroblast growth factor have been shown to promote proliferation and differentiation of osteoblasts from precursor cells. The intense presence of insulin-like growth factor I and basic fibroblast growth factor in the distracted region may account for osteoblast proliferation and formation from

  10. Conformational thermostabilisation of corticotropin releasing factor receptor 1

    PubMed Central

    Kean, James; Bortolato, Andrea; Hollenstein, Kaspar; Marshall, Fiona H.; Jazayeri, Ali

    2015-01-01

    Recent technical advances have greatly facilitated G-protein coupled receptors crystallography as evidenced by the number of successful x-ray structures that have been reported recently. These technical advances include novel detergents, specialised crystallography techniques as well as protein engineering solutions such as fusions and conformational thermostabilisation. Using conformational thermostabilisation, it is possible to generate variants of GPCRs that exhibit significantly increased stability in detergent micelles whilst preferentially occupying a single conformation. In this paper we describe for the first time the application of this technique to a member of a class B GPCR, the corticotropin releasing factor receptor 1 (CRF1R). Mutational screening in the presence of the inverse agonist, CP-376395, resulted in the identification of a construct with twelve point mutations that exhibited significantly increased thermal stability in a range of detergents. We further describe the subsequent construct engineering steps that eventually yielded a crystallisation-ready construct which recently led to the solution of the first x-ray structure of a class B receptor. Finally, we have used molecular dynamic simulation to provide structural insight into CRF1R instability as well as the stabilising effects of the mutants, which may be extended to other class B receptors considering the high degree of structural conservation. PMID:26159865

  11. Skeletal Myogenic Differentiation of Urine-Derived Stem Cells and Angiogenesis Using Microbeads Loaded with Growth Factors

    PubMed Central

    Liu, Guihua; Pareta, Rajesh A; Wu, Rongpei; Shi, Yingai; Zhou, Xiaobo; Liu, Hong; Deng, Chunhua; Sun, Xiangzhou; Atala, Anthony; Opara, Emmanuel C; Zhang, Yuanyuan

    2012-01-01

    To provide site-specific delivery and targeted release of growth factors to implanted urine-derived stem cells (USCs), we prepared microbeads of alginate containing growth factors. The growth factors included VEGF, IGF-1, FGF-1, PDGF, HGF and NGF. Radiolabeled growth factors were loaded separately and used to access the in vitro release from the microbeads with a gamma counter over 4 weeks. In vitro endothelial differentiation of USCs by the released VEGF from the microbeads in a separate experiment confirmed that the released growth factors from the microbeads were bioactive. USCs and microbeads were mixed with the collagen gel type 1 (2 mg/ml) and used for in vivo studies through subcutaneous injection into nude mice. Four weeks after subcutaneous injection, we found that grafted cell survival was improved and more cells expressed myogenic and endothelial cell transcripts and markers compared to controls. More vessel formation and innervations were observed in USCs combined with six growth factors cocktail incorporated in microbeads compared to controls. In conclusion, a combination of growth factors released locally from the alginate microbeads induced USCs to differentiate into a myogenic lineage, enhanced revascularization and innervation, and stimulated resident cell growth in vivo. This approach could potentially be used for cell therapy in the treatment of stress urinary incontinence. PMID:23137393

  12. Modeling vascularized bone regeneration within a porous biodegradable CaP scaffold loaded with growth factors.

    PubMed

    Sun, Xiaoqiang; Kang, Yunqing; Bao, Jiguang; Zhang, Yuanyuan; Yang, Yunzhi; Zhou, Xiaobo

    2013-07-01

    Osteogenetic microenvironment is a complex constitution in which extracellular matrix (ECM) molecules, stem cells and growth factors each interact to direct the coordinate regulation of bone tissue development. Importantly, angiogenesis improvement and revascularization are critical for osteogenesis during bone tissue regeneration processes. In this study, we developed a three-dimensional (3D) multi-scale system model to study cell response to growth factors released from a 3D biodegradable porous calcium phosphate (CaP) scaffold. Our model reconstructed the 3D bone regeneration system and examined the effects of pore size and porosity on bone formation and angiogenesis. The results suggested that scaffold porosity played a more dominant role in affecting bone formation and angiogenesis compared with pore size, while the pore size could be controlled to tailor the growth factor release rate and release fraction. Furthermore, a combination of gradient VEGF with BMP2 and Wnt released from the multi-layer scaffold promoted angiogenesis and bone formation more readily than single growth factors. These results demonstrated that the developed model can be potentially applied to predict vascularized bone regeneration with specific scaffold and growth factors.

  13. 76 FR 68183 - Highlights of the Exposure Factors Handbook: 2011 Update Release of Final Report

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-03

    ... Exposure Factors Handbook: 2011 Update Release of Final Report AGENCY: Environmental Protection Agency (EPA... Environmental Assessment (NCEA) within EPA's Office of Research and Development. The parent Exposure Factors... in assessing exposure to environmental chemicals. The Highlights of the Exposure Factors...

  14. Hypromellose films for the delivery of growth factors for wound healing.

    PubMed

    Braund, Rhiannon; Tucker, Ian G; Medlicott, Natalie J

    2007-03-01

    Hypromellose was investigated as a carrier for extending topical growth factor delivery to wounds. Films of hypromellose (E4M, K4M and E10M) containing a model protein horseradish peroxidase (1% w/w HRP, MW 40 000) were cast from aqueous solutions and dried at 37 degrees C. In-vitro release was determined using Franz-type diffusion cells and films were mounted directly into the Franz cell or cast onto a wound dressing (Melolin) backing. There was an initial burst release then an extended release over 5 h. The Melolin backing significantly reduced the burst but not the extended release rates (P < 0.05). Release of HRP was also determined from 7% w/v hypromellose gels and was significantly lower for E10M than E4M, suggesting that, once hydrated, the E10M hypromellose provides the greatest resistance to HRP release. The release profile of basic fibroblast growth factor from Melolin-backed films made from E4M hypromellose was not significantly different at any time point to that of HRP release from the same formulation. Hypromellose may be incorporated into a wound dressing such as Melolin to provide a prolonged release of an incorporated protein active.

  15. PLACENTAL GROWTH FACTOR ADMINISTRATION ABOLISHES PLACENTAL ISCHEMIA-INDUCED HYPERTENSION

    PubMed Central

    Spradley, Frank T.; Tan, Adelene Y.; Joo, Woo S.; Daniels, Garrett; Kussie, Paul; Karumanchi, S. Ananth; Granger, Joey P.

    2016-01-01

    Preeclampsia is a pregnancy-specific disorder of new-onset hypertension. Unfortunately, the most effective treatment is early delivery of the fetus and placenta. Placental ischemia appears central to the pathogenesis of preeclampsia as placental ischemia/hypoxia induced in animals by reduced uterine perfusion pressure (RUPP) or in humans stimulates release of hypertensive placental factors into the maternal circulation. The anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes and reduces bioavailable vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), is elevated in RUPP rats and preeclampsia. Although PlGF and VEGF are both natural ligands for sFlt-1, VEGF also has high affinity to VEGFR2 (Flk-1) causing side effects like edema. PlGF is specific for sFlt-1. We tested the hypothesis that PlGF treatment reduces placental ischemia-induced hypertension by antagonizing sFlt-1 without adverse consequences to the mother or fetus. On gestational day 14, rats were randomized to four groups: normal pregnant (NP) or RUPP ± infusion of rhPlGF (180 μg/kg/day; AG31, a purified, recombinant human form of PlGF) for 5 days via intraperitoneal osmotic minipumps. On day 19, mean arterial blood pressure and plasma sFlt-1 were higher and glomerular filtration rate lower in RUPP than NP rats. Infusion of rhPlGF abolished these changes seen with RUPP along with reducing oxidative stress. These data indicate that the increased sFlt-1 and reduced PlGF resulting from placental ischemia contribute to maternal hypertension. Our novel finding that rhPlGF abolishes placental ischemia-induced hypertension, without major adverse consequences, suggests a strong therapeutic potential for this growth factor in preeclampsia. PMID:26831193

  16. Release of extracellular ATP by bacteria during growth

    PubMed Central

    2013-01-01

    Background Adenosine triphosphate (ATP) is used as an intracellular energy source by all living organisms. It plays a central role in the respiration and metabolism, and is the most important energy supplier in many enzymatic reactions. Its critical role as the energy storage molecule makes it extremely valuable to all cells. Results We report here the detection of extracellular ATP in the cultures of a variety of bacterial species. The levels of the extracellular ATP in bacterial cultures peaked around the end of the log phase and decreased in the stationary phase of growth. Extracellular ATP levels were dependent on the cellular respiration as bacterial mutants lacking cytochrome bo oxidase displayed lower extracellular ATP levels. We have also shown that Escherichia coli (E. coli) and Salmonella actively depleted extracellular ATP and an ATP supplement in culture media enhanced the stationary survival of E. coli and Salmonella. In addition to E. coli and Salmonella the presence of the extracellular ATP was observed in a variety of bacterial species that contain human pathogens such as Acinetobacter, Pseudomonas, Klebsiella and Staphylococcus. Conclusion Our results indicate that extracellular ATP is produced by many bacterial species during growth and extracellular ATP may serve a role in the bacterial physiology. PMID:24364860

  17. Search for novel therapies for triple negative breast cancers (TNBC): analogs of luteinizing hormone-releasing hormone (LHRH) and growth hormone-releasing hormone (GHRH).

    PubMed

    Buchholz, Stefan; Seitz, Stephan; Engel, Jörg B; Montero, Alberto; Ortmann, Olaf; Perez, Roberto; Block, Norman L; Schally, Andrew V

    2012-04-01

    Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype that is clinically negative for the expression of estrogen and progesterone receptors (ER/PR) and human epidermal growth factor receptor-2 (HER2). Patients with TNBC have a worse clinical outcome, as measured by time to metastasis and median overall survival. Chemotherapy has been the mainstay of treatment of TNBC but responses are disappointing. A substantial proportion of TNBC expresses luteinizing hormone-releasing hormone (LHRH), receptors for LHRH, in addition to receptors for growth hormone-releasing hormone (GHRH). These receptors represent potential therapeutic targets. Potent antagonists of GHRH and LHRH receptors have been developed in recent years and these antagonists inhibit the growth, tumorigenicity and metastatic potential of various human experimental malignancies. These antagonists could be utilized for the treatment of TNBC. The targeted cytotoxic analog of LHRH, AN-152 (AEZS-108) containing doxorubicin, must also be strongly considered for therapy of TNBC. Experimental studies suggest the merit of clinical trials with LHRH antagonists and AEZS-108 in TNBC patients.

  18. Stress-Derived Corticotropin Releasing Factor Breaches Epithelial Endotoxin Tolerance

    PubMed Central

    Yu, Yong; Geng, Xiao-Rui; Yang, Gui; Liu, Zhi-Gang; Zheng, Peng-Yuan; Yang, Ping-Chang

    2013-01-01

    Background and aims Loss of the endotoxin tolerance of intestinal epithelium contributes to a number of intestinal diseases. The etiology is not clear. Psychological stress is proposed to compromise the intestinal barrier function. The present study aims to elucidate the role of the stress-derived corticotropin releasing factor (CRF) in breaching the established intestinal epithelial endotoxin tolerance. Methods Epithelial cells of HT-29, T84 and MDCK were exposed to lipopolysaccharide to induce the endotoxin tolerance; the cells were then stimulated with CRF. The epithelial barrier function was determined using as indicators of the endotoxin tolerant status. A water-avoid stress mouse model was employed to test the role of CRF in breaching the established endotoxin tolerance in the intestine. Results The established endotoxin tolerance in the epithelial cell monolayers was broken down by a sequent exposure to CRF and LPS manifesting a marked drop of the transepithelial resistance (TER) and an increase in the permeability to a macromolecular tracer, horseradish peroxidase (HRP). The exposure to CRF also increased the expression of Cldn2 in the epithelial cells, which could be mimicked by over expression of TLR4 in epithelial cells. Over expression of Cldn2 resulted in low TER in epithelial monolayers and high permeability to HRP. After treating mice with the 10-day chronic stress, the intestinal epithelial barrier function was markedly compromised, which could be prevented by blocking either CRF, or TLR4, or Cldn2. Conclusions Psychological stress-derived CRF can breach the established endotoxin tolerance in the intestinal mucosa. PMID:23840363

  19. Autologous Growth Factor Injections in Chronic Tendinopathy

    PubMed Central

    Sandrey, Michelle A.

    2014-01-01

    Reference: de Vos RJ, van Veldhoven PLJ, Moen MH, Weir A, Tol JL. Autologous growth factor injections in chronic tendinopathy: a systematic review. Br Med Bull. 2010;95:63–77. Clinical Question: The authors of this systematic review evaluated the literature to critically consider the effects of growth factors delivered through autologous whole-blood and platelet-rich–plasma (PRP) injections in managing wrist-flexor and -extensor tendinopathies, plantar fasciopathy, and patellar tendinopathy. The primary question was, according to the published literature, is there sufficient evidence to support the use of growth factors delivered through autologous whole-blood and PRP injections for chronic tendinopathy? Data Sources: The authors performed a comprehensive, systematic literature search in October 2009 using PubMed, MEDLINE, EMBASE, CINAHL, and the Cochrane library without time limits. The following key words were used in different combinations: tendinopathy, tendinosis, tendinitis, tendons, tennis elbow, plantar fasciitis, platelet rich plasma, platelet transfusion, and autologous blood or injection. The search was limited to human studies in English. All bibliographies from the initial literature search were also viewed to identify additional relevant studies. Study Selection: Studies were eligible based on the following criteria: (1) Articles were suitable (inclusion criteria) if the participants had been clinically diagnosed as having chronic tendinopathy; (2) the design had to be a prospective clinical study, randomized controlled trial, nonrandomized clinical trial, or prospective case series; (3) a well-described intervention in the form of a growth factor injection with either PRP or autologous whole blood was used; and (4) the outcome was reported in terms of pain or function (or both). Data Extraction: All titles and abstracts were assessed by 2 researchers, and all relevant articles were obtained. Two researchers independently read the full text of

  20. The role of growth factors in wound healing.

    PubMed

    Steed, D L

    1997-06-01

    Growth factors applied topically to wounds can accelerate healing by stimulating granulation tissue formation and enhancing epithelialization. This has been suggested by several different studies of topically applied growth factors. It is clear, however, that topical growth factor therapy should not be considered as a substitute for good wound care, including surgical debridement or revascularization.

  1. Transforming growth factor beta regulates thyroid growth. Role in the pathogenesis of nontoxic goiter.

    PubMed Central

    Grubeck-Loebenstein, B; Buchan, G; Sadeghi, R; Kissonerghis, M; Londei, M; Turner, M; Pirich, K; Roka, R; Niederle, B; Kassal, H

    1989-01-01

    The production and growth regulatory activity of transforming growth factor beta were studied in human thyroid tissue. As estimated by its mRNA expression in fresh tissue samples, transforming growth factor beta was produced in normal and in diseased thyroid glands. Transforming growth factor beta mRNA was mainly produced by thyroid follicular cells and in lesser quantities by thyroid infiltrating mononuclear cells. The concentrations of transforming growth factor beta mRNA were lower in iodine-deficient nontoxic goiter than in Graves' disease and normal thyroid tissue. Transforming growth factor beta protein secretion by cultured thyroid follicular cells was also low in nontoxic goiter, but could be increased by addition of sodium iodide (10 microM) to the culture medium. Recombinant transforming growth factor beta did not affect basal tritiated thymidine incorporation in cultured thyroid follicular cells, but inhibited, at a concentration of 10 ng/ml, the growth stimulatory influence of insulin-like growth factor I, epidermal growth factor, transforming growth factor alpha, TSH, and partly that of normal human serum on cultured thyroid follicular cells. This inhibition was greater in Graves' disease than in nontoxic goiter. These results suggest that transforming growth factor beta may act as an autocrine growth inhibitor on thyroid follicular cells. Decreased transforming growth factor beta production and decreased responsiveness to transforming growth factor beta may be cofactors in the pathogenesis of iodine-deficient nontoxic goiter. Images PMID:2921318

  2. Insulin/IGF signaling in Drosophila and other insects: factors that regulate production, release and post-release action of the insulin-like peptides.

    PubMed

    Nässel, Dick R; Vanden Broeck, Jozef

    2016-01-01

    Insulin, insulin-like growth factors (IGFs) and insulin-like peptides (ILPs) are important regulators of metabolism, growth, reproduction and lifespan, and mechanisms of insulin/IGF signaling (IIS) have been well conserved over evolution. In insects, between one and 38 ILPs have been identified in each species. Relatively few insect species have been investigated in depth with respect to ILP functions, and therefore we focus mainly on the well-studied fruitfly Drosophila melanogaster. In Drosophila eight ILPs (DILP1-8), but only two receptors (dInR and Lgr3) are known. DILP2, 3 and 5 are produced by a set of neurosecretory cells (IPCs) in the brain and their biosynthesis and release are controlled by a number of mechanisms differing between larvae and adults. Adult IPCs display cell-autonomous sensing of circulating glucose, coupled to evolutionarily conserved mechanisms for DILP release. The glucose-mediated DILP secretion is modulated by neurotransmitters and neuropeptides, as well as by factors released from the intestine and adipocytes. Larval IPCs, however, are indirectly regulated by glucose-sensing endocrine cells producing adipokinetic hormone, or by circulating factors from the intestine and fat body. Furthermore, IIS is situated within a complex physiological regulatory network that also encompasses the lipophilic hormones, 20-hydroxyecdysone and juvenile hormone. After release from IPCs, the ILP action can be modulated by circulating proteins that act either as protective carriers (binding proteins), or competitive inhibitors. Some of these proteins appear to have additional functions that are independent of ILPs. Taken together, the signaling with multiple ILPs is under complex control, ensuring tightly regulated IIS in the organism.

  3. Growth factor control of epidermal growth factor receptor kinase activity via an intramolecular mechanism.

    PubMed

    Koland, J G; Cerione, R A

    1988-02-15

    The mechanism by which the protein kinase activity of the epidermal growth factor (EGF) receptor is activated by binding of growth factor was investigated. Detergent-solubilized receptor in monomeric form was isolated by sucrose density gradient centrifugation and both its kinase and autophosphorylation activities monitored. In a low ionic strength medium and with MnCl2 as an activator, the activity of the monomeric receptor was EGF-independent. However, with 0.25 M ammonium sulfate present, the MnCl2-stimulated kinase activity was strikingly EGF-dependent. In contrast, the kinase activity expressed in the presence of MgCl2 showed growth factor control in the absence of added salt. Under the conditions of these experiments there was apparently little tendency for growth factor to induce aggregation of the receptor, indicating that the allosteric activation of the receptor kinase by EGF occurred via an intramolecular mechanism. Whereas detergent-solubilized receptor was the subject of these studies, the kinase activity of cell surface receptors might also be controlled by an intramolecular mechanism. These results indicate that an individual receptor molecule has the potential to function as a transmembrane signal transducer.

  4. Fibroblast Growth Factor Signaling in the Developing Neuroendocrine Hypothalamus

    PubMed Central

    Tsai, Pei-San; Brooks, Leah R.; Rochester, Johanna R.; Kavanaugh, Scott I.; Chung, Wilson C. J.

    2011-01-01

    Fibroblast growth factor (FGF) signaling is pivotal to the formation of numerous central regions. Increasing evidence suggests FGF signaling also directs the development of the neuroendocrine hypothalamus, a collection of neuroendocrine neurons originating primarily within the nose and the ventricular zone of the diencephalon. This review outlines evidence for a role of FGF signaling in the prenatal and postnatal development of several hypothalamic neuroendocrine systems. The emphasis is placed on the nasally derived gonadotropin- releasing hormone neurons, which depend on neurotrophic cues from FGF signaling throughout the neurons' lifetime. Although less is known about neuroendocrine neurons derived from the diencephalon, recent studies suggest they also exhibit variable levels of dependence on FGF signaling. Overall, FGF signaling provides a broad spectrum of cues that ranges from genesis, cell survival/death, migration, morphological changes, to hormone synthesis in the neuroendocrine hypothalamus. Abnormal FGF signaling will deleteriously impact multiple hypothalamic neuroendocrine systems, resulting in the disruption of diverse physiological functions. PMID:21129392

  5. Proteasome Inhibition by Fellutamide B Induces Nerve Growth Factor Synthesis

    PubMed Central

    Hines, John; Groll, Michael; Fahnestock, Margaret; Crews, Craig M.

    2008-01-01

    SUMMARY Neurotrophic small molecules have the potential to aid in the treatment of neuronal injury and neurodegenerative diseases. The natural product fellutamide B, originally isolated from Penicillium fellutanum, potently induces nerve growth factor (NGF) release from fibroblasts and glial-derived cells, although the mechanism for this neurotrophic activity has not been elucidated. Here, we report that fellutamide B potently inhibits proteasome catalytic activity. High resolution structural information obtained from co-crystallization of the 20S proteasome reveals novel aspects regarding β-subunit binding and adduct formation by fellutamide B to inhibit their hydrolytic activity. We demonstrate that fellutamide B and other proteasome inhibitors increased NGF gene transcription via a cis-acting element (or elements) in the promoter. These results demonstrate an unrecognized connection between proteasome inhibition and NGF production, suggesting a possible new strategy in the development of neurotrophic agents. PMID:18482702

  6. Prolactin, thyrotropin, and growth hormone release during stress associated with parachute jumping.

    PubMed

    Noel, G L; Dimond, R C; Earll, J M; Frantz, A G

    1976-05-01

    Prolactin, growth hormone, and thyrotropin (TSH) release during the stress of parachute jumping has been evaluated in 14 male subjects. Subjects were studied at several times before and immediately after their first military parachute jump. All three hormones had risen significantly 1 to 14 min after the jump, compared to mean levels measured immediately beforehand. Earlier studies of physical exercise by ourselves and others would suggest that emotional stress played a role in producing changes of this magnitude. We conclude that prolactin, TSH, and growth hormone are released in physiologically significant amounts in association with the stress of parachute jumping.

  7. Resin-modified glass ionomer cements: fluoride release and influence on Streptococcus mutans growth.

    PubMed

    Friedl, K H; Schmalz, G; Hiller, K A; Shams, M

    1997-02-01

    The aims of the present study were to measure the fluoride release of 1 glass ionomer cement, 1 cermet, 3 resin-modified glass ionomer cements and 1 compomer, and to determine the influence of each material on bacterial growth. Test specimens were eluted in saline for 180 days. Every 2 days, the specimens were transferred into fresh saline and the fluoride content of the solution was measured. Furthermore, 48-h, 14-d, 90-d, and 180-d eluates were inoculated with Streptococcus mutans and bacterial growth was recorded nephelometrically. Fluoride release dropped significantly over time for each material with values between 6.2 (Ketac-Silver) and 29.3 (Photac-Fil) ppm after 48 h to values between 0.6 (Ketac-Silver) and 1.7 (Ketac-Fil, Vitremer) ppm after 180 days. Each material reduced bacterial growth at each time of examination, but the effect decreased significantly over time with a maximum growth of 71.7% (Ketac-Fil) to 85.6% (Ketac-Silver) after 48 h and 94.7 (Vitremer) to 99.0% (Ketac-Silver) after 180 days (growth control = 100%). Both Ketac-Silver and Dyract showed a significantly lower inhibiting effect on bacterial growth than the other materials. The tested materials showed a good correlation between fluoride release and influence on bacterial growth. However, both effects dropped dramatically over the 180-days period.

  8. The Fibroblast Growth Factor signaling pathway

    PubMed Central

    Ornitz, David M; Itoh, Nobuyuki

    2015-01-01

    The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins. Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways. Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels. Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning. FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways. Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer. © 2015 Wiley Periodicals, Inc. PMID:25772309

  9. Hormonal and lactational responses to growth hormone-releasing hormone treatment in lactating Japanese Black cows.

    PubMed

    Shingu, H; Hodate, K; Kushibiki, S; Ueda, Y; Touno, E; Shinoda, M; Ohashi, S

    2004-06-01

    Ten multiparous lactating Japanese Black cows (beef breed) were used to evaluate the effects of bovine growth hormone-releasing hormone (GHRH) analog on milk yield and profiles of plasma hormones and metabolites. The cows received 2 consecutive 21-d treatments (a daily s.c. injection of 3-mg GHRH analog or saline) in a 2 (group) x 2 (period) Latin square crossover design. The 5 cows in group A received GHRH analog during period 1 (from d 22 to 42 postpartum) and saline during period 2 (from d 57 to 77 postpartum), and those in group B received saline and GHRH analog during periods 1 and 2, respectively. Mean milk yield decreased in saline treated compared with that during the 1-wk period before treatment 7.4 and 19.1% during periods 1 (group B) and 2 (group A), respectively. Treatment with GHRH analog increased milk yield 17.4% (period 1, group A) and 6.3% (period 2, group B). Treatment with GHRH analog induced higher basal plasma concentrations of growth hormone (GH), insulin-like growth factor-1 (IGF-1), insulin, and glucose compared with saline-treated cows. In glucose challenge, the GHRH analog-treated beef cows had greater insulin secretion than the saline-treated beef cows. In insulin challenge, however, there were no significant differences in the areas surrounded by hypothetical lines of basal glucose concentrations and glucose response curves between GHRH analog- and saline-treated cows. These results demonstrate that GHRH analog treatment facilitates endogenous GH secretion in lactating Japanese Black cows, leading to increases in milk yield and plasma concentrations of IGF-1, insulin, and glucose.

  10. [Growth Hormone-Insulin Growth Factor I (GH-IGF-I) axis and growth].

    PubMed

    Castell, A-L; Sadoul, J-L; Bouvattier, C

    2013-10-01

    Normal human linear growth results from an evolutionary process expressing the sum effect of multiple genes. The growth hormone (GH) - insulin like growth factor (IGF)-I axis is one of the main actors in the growth process. Defects in this axis can be responsible for short or tall stature. Short stature is defined as smaller than - 2 standard deviations (SD). It is a very common reason for consultation in pediatrics; indeed, 2.5 % of children are concerned. Multiple causes make diagnosis difficult. In this article, we detail the most common constitutional causes of small size, including those related to a defect in the GH-IGF-I axis. Then, we report, the first results of the clinical and genetic study conducted on 213 patients with gigantism. Tall stature is defined by a height superior to 2 SD. Finally, recent work linking epigenetics and growth - via signaling pathways of GH-IGF-I axis - will be presented.

  11. [Ca2+ release from intracellular stores of pig oocytes during different stages of growth].

    PubMed

    Denisenko, V Iu; Kuz'mina, T I

    2011-01-01

    Ca2+ release from intracellular stores of pig oocytes was investigated using the Ca(2+)-sensitive fluorescent dye chlorotetracycline. Oocytes were divided into growing ones and those that completed their growth using brilliant cresyl clue (BCB) staining. The stained oocytes (BCB "+") were determined as the ones that completed their growth, while the stainless ones (BCB "-") were determined as those in the final stages of growth. In the BCB "+" and BCB "-" oocytes, prolactin, theophylline, GTP, and GDP cause Ca2+ to exit intracellular stores. In the oocytes that completed their growth, joint action of prolactin and GTP activates additional release of Ca2+, in which protein kinase C takes part. In growing oocytes, joint action of prolactin and GTP does not lead to additional release of Ca2+. Joint action of theophylline and GDP in growing oocytes and oocytes that completed the growth stage promotes additional Ca2+ exit from intracellular stores. This exit is regulated by protein kinase A. The obtained data show that there various routes of Ca2+ release from intracellular stores in growing and grown pig oocytes.

  12. Affinity-based growth factor delivery using biodegradable, photocrosslinked heparin-alginate hydrogels

    PubMed Central

    Jeon, Oju; Powell, Caitlin; Solorio, Loran D.; Krebs, Melissa D.; Alsberg, Eben

    2013-01-01

    Photocrosslinkable biomaterials are promising for tissue engineering applications due to their capacity to be injected and form hydrogels in situ in a minimally invasive manner. Our group recently reported on the development of photocrosslinked alginate hydrogels with controlled biodegradation rates, mechanical properties, and cell adhesive properties. In this study, we present an affinity-based growth factor delivery system by incorporating heparin into photocrosslinkable alginate hydrogels (HP-ALG), which allows for controlled, prolonged release of therapeutic proteins. Heparin modification had minimal effect on the biodegradation profiles, swelling ratios, and elastic moduli of the hydrogels in media. The release profiles of growth factors from this affinity-based platform were sustained for 3 weeks with no initial burst release, and the released growth factors retained their biological activity. Implantation of bone morphogenetic protein-2 (BMP-2)-loaded photocrosslinked alginate hydrogels induced moderate bone formation around the implant periphery. Importantly, BMP-2-loaded photocrosslinked HP-ALG hydrogels induced significantly more osteogenesis than BMP-2-loaded photocrosslinked unmodified alginate hydrogels, with 1.9-fold greater peripheral bone formation and 1.3-fold greater calcium content in the BMP-2-loaded photocrosslinked HP-ALG hydrogels compared to the BMP-2-loaded photocrosslinked unmodified alginate hydrogels after 8 weeks implantation. This sustained and controllable growth factor delivery system, with independently controllable physical and cell adhesive properties, may provide a powerful modality for a variety of therapeutic applications. PMID:21745508

  13. Ribosome release factor RF4 and termination factor RF3 are involved in dissociation of peptidyl-tRNA from the ribosome.

    PubMed Central

    Heurgué-Hamard, V; Karimi, R; Mora, L; MacDougall, J; Leboeuf, C; Grentzmann, G; Ehrenberg, M; Buckingham, R H

    1998-01-01

    Peptidyl-tRNA dissociation from ribosomes is an energetically costly but apparently inevitable process that accompanies normal protein synthesis. The drop-off products of these events are hydrolysed by peptidyl-tRNA hydrolase. Mutant selections have been made to identify genes involved in the drop-off of peptidyl-tRNA, using a thermosensitive peptidyl-tRNA hydrolase mutant in Escherichia coli. Transposon insertions upstream of the frr gene, which encodes RF4 (ribosome release or recycling factor), restored growth to this mutant. The insertions impaired expression of the frr gene. Mutations inactivating prfC, encoding RF3 (release factor 3), displayed a similar phenotype. Conversely, production of RF4 from a plasmid increased the thermosensitivity of the peptidyl-tRNA hydrolase mutant. In vitro measurements of peptidyl-tRNA release from ribosomes paused at stop signals or sense codons confirmed that RF3 and RF4 were able to stimulate peptidyl-tRNA release from ribosomes, and showed that this action of RF4 required the presence of translocation factor EF2, known to be needed for the function of RF4 in ribosome recycling. When present together, the three factors were able to stimulate release up to 12-fold. It is suggested that RF4 may displace peptidyl-tRNA from the ribosome in a manner related to its proposed function in removing deacylated tRNA during ribosome recycling. PMID:9451005

  14. Evaluation of growth hormone release and human growth hormone treatment in children with cranial irradiation-associated short stature

    SciTech Connect

    Romshe, C.A.; Zipf, W.B.; Miser, A.; Miser, J.; Sotos, J.F.; Newton, W.A.

    1984-02-01

    We studied nine children who had received cranial irradiation for various malignancies and subsequently experienced decreased growth velocity. Their response to standard growth hormone stimulation and release tests were compared with that in seven children with classic GH deficiency and in 24 short normal control subjects. With arginine and L-dopa stimulation, six of nine patients who received radiation had a normal GH response (greater than 7 ng/ml), whereas by design none of the GH deficient and all of the normal children had a positive response. Only two of nine patients had a normal response to insulin hypoglycemia, with no significant differences in the mean maximal response of the radiation and the GH-deficient groups. Pulsatile secretion was not significantly different in the radiation and GH-deficient groups, but was different in the radiation and normal groups. All subjects in the GH-deficient and radiation groups were given human growth hormone for 1 year. Growth velocity increased in all, with no significant difference in the response of the two groups when comparing the z scores for growth velocity of each subject's bone age. We recommend a 6-month trial of hGH in children who have had cranial radiation and are in prolonged remission with a decreased growth velocity, as there is no completely reliable combination of GH stimulation or release tests to determine their response.

  15. Identification of the growth-hormone-releasing peptide-2 (GHRP-2) in a nutritional supplement.

    PubMed

    Thomas, Andreas; Kohler, Maxie; Mester, Joachim; Geyer, Hans; Schänzer, Wilhelm; Petrou, Michael; Thevis, Mario

    2010-03-01

    Black market products of a pharmaceutical nature and nutritional supplements have received substantial and increasing attention because of potential performance enhancement in elite and non-professional sports. In addition, improved general health is claimed for non-competing individuals. The risks and foreseeable dangers of the uncontrolled use of highly potent and non-approved pharmaceutical compounds in healthy individuals are of considerable concern. In the present case report, the emerging drug candidate GHRP-2 with verified growth-hormone-releasing properties was identified and quantified in tablets offered as an over-the-counter nutritional supplement. The impact of this orally active peptide on the hGH/IGF-axis has been established for several years and its illicit use in elite sports has been assumed. As a releasing factor for hGH, GHRP-2 belongs to the list of substances prohibited by the World Anti-Doping Agency (WADA). Unfortunately, to date there is no routinely performed assay for the determination of these peptides potentially occurring in biological fluids of competing athletes, but the present data will facilitate the implementation by providing principle analytical information on liquid chromatographic and mass spectrometric behaviour. Qualitative identification of the target analyte after extraction from the tablet matrix was performed by high resolution/high accuracy mass spectrometry after liquid chromatographic separation under consideration of the accurate masses and the ratios of the protonated molecules and their fragment ions derived from their collisionally induced dissociation. Quantitative results were obtained by means of liquid chromatography coupled to a triple quadrupole mass spectrometer and linear regression using an external calibration curve (with GHRP-2 reference compound) adjusted via internal standard (Hexarelin). Hereby, the content of GHRP-2 was determined with approximately 50 µg per tablet.

  16. Effect of catch-and-release angling on growth and survival of rainbow trout, Oncorhynchus mykiss

    USGS Publications Warehouse

    Pope, K.L.; Wilde, G.R.; Knabe, D.W.

    2007-01-01

    Catch-and-release angling is popular in many parts of the world and plays an increasingly important role in fish conservation efforts. Although survival rates associated with catch-and-release angling are well documented for many species, sublethal effects have been less studied. An experiment was conducted to directly assess the effects of catch-and-release angling on growth and survival of rainbow trout, Oncorhynchus mykiss (Walbaum). Catch-and-release events were simulated in laboratory tanks maintained at 15-16 ??C with hooks manually placed in pre-designated locations in the mouths of the fish. There were no differences in standard length (P = 0.59) or wet weight (P = 0.81) gained between caught and uncaught fish over a 1-month angling and recovery period. Survival was 96.99 ?? 0.06% for rainbow trout caught and released, and did not vary with number (one, two or four) of captures. Thus, catch-and-release angling appears to have little effect on growth and mortality of rainbow trout hooked in the mouth. ?? 2007 The Authors. Journal compilation 2007 Blackwell Publishing Ltd.

  17. [Effects of slow/controlled release fertilizers on the growth and nutrient use efficiency of pepper].

    PubMed

    Tang, Shuan-Hu; Zhang, Fa-Bao; Huang, Xu; Chen, Jian-Sheng; Xu, Pei-Zhi

    2008-05-01

    Pot trails were conducted from 2003 to 2005 to study the effects of slow/controlled release fertilizers on the growth and nutrient use efficiency of pepper. The results indicated that in comparison with conventional splitting fertilization (T1), basal application of polymer-coated controlled release fertilizer (T2) enhanced the single fruit mass and vitamin C concentration, improved the root activity, and increased the fruit yield by 8.4%, but no significant effect was observed on the dissoluble sugar concentration in fruit. NH4MgPO4-coated controlled release fertilizer (T3) increased the dissoluble sugar concentration by 5.67%, but had less effect on single fruit mass and vitamin C concentration. Under the application of T3, the root system had a vigorous growth at early stages but became infirm at later stages, resulting in a lower yield. Comparing with T1, the application of 3 slow release fertilizers increased the dissoluble sugar concentration in fruit, enhanced the root activity, but had less effect on the yield. All test slow/controlled release fertilizers increased the use efficiency of N, P, and K significantly, with an exception for T2 which increased the use efficiency of N and K but decreased that of P. It was demonstrated that an appropriate application of slow/controlled release fertilizers could enhance pepper' s root activity and improve nutrient use efficiency.

  18. Design and characteristics of cytotoxic fibroblast growth factor 1 conjugate for fibroblast growth factor receptor-targeted cancer therapy

    PubMed Central

    Szlachcic, Anna; Zakrzewska, Malgorzata; Lobocki, Michal; Jakimowicz, Piotr; Otlewski, Jacek

    2016-01-01

    Fibroblast growth factor receptors (FGFRs) are attractive candidate cancer therapy targets as they are overexpressed in multiple types of tumors, such as breast, prostate, bladder, and lung cancer. In this study, a natural ligand of FGFR, an engineered variant of fibroblast growth factor 1 (FGF1V), was conjugated to a potent cytotoxic drug, monomethyl auristatin E (MMAE), and used as a targeting agent for cancer cells overexpressing FGFRs, similar to antibodies in antibody–drug conjugates. The FGF1V–valine–citrulline–MMAE conjugate showed a favorable stability profile, bound FGFRs on the cell surface specifically, and efficiently released the drug (MMAE) upon cleavage by the lysosomal protease cathepsin B. Importantly, the conjugate showed a prominent cytotoxic effect toward cell lines expressing FGFR. FGF1V–vcMMAE was highly cytotoxic at concentrations even an order of magnitude lower than those found for free MMAE. This effect was FGFR-specific as cells lacking FGFR did not show any increased mortality. PMID:27563235

  19. Application of photoremovable protecting group for controlled release of plant growth regulators by sunlight.

    PubMed

    Atta, Sanghamitra; Ikbal, Mohammed; Kumar, Ashutosh; Pradeep Singh, N D

    2012-06-04

    We report a novel technique for controlled release of plant growth regulators (PGRs) by sunlight using photoremovable protecting group (PRPG) as a delivery device. In the present work, carboxyl-containing PGRs of the auxin group [indoleacetic acid (IAA) and naphthoxyacetic acid (NOAA)] were chemically caged using PRPGs of coumarin derivatives. Photophysical studies showed that caged PGRs exhibited good fluorescence properties. Irradiation of caged PGRs by sunlight in both aqueous ethanol and soil media resulted in controlled release of PGRs. The results of the bioactivity experiments indicated that caged PGRs showed better enhancement in the root and shoot length growth of Cicer arietinum compared to PGRs after 10days of sunlight exposure. Our results indicated that use of PRPG as a delivery device for controlled release of PGRs by sunlight in soil holds great interest for field application since it can overcome the rapid loss of PGRs in environmental conditions.

  20. Endorsement of Growth Factors in Experiential Training Groups

    ERIC Educational Resources Information Center

    Kiweewa, John; Gilbride, Dennis; Luke, Melissa; Seward, Derek

    2013-01-01

    The purpose of this study was to identify student growth factors during a semester long Master's level group counseling class. Results indicated that 12 growth factors accounted for 86% of the total number of critical incidents that participants reported as influencing their personal growth and awareness during the group experience. Two other…

  1. Multifunctional mesoporous bioactive glasses for effective delivery of therapeutic ions and drug/growth factors.

    PubMed

    Wu, Chengtie; Chang, Jiang

    2014-11-10

    Regeneration of large-size bone defects represents a significant challenge clinically, which requires the use of scaffolds with multifunction, such as anti-bacterial activity, and stimulation of osteogenesis and angiogenesis. It is known that functional ions or drug/growth factors play an important role to stimulate tissue regeneration. Mesoporous bioactive glasses (MBG) possess excellent bioactivity and drug-delivery ability as well as effective ionic release in the body fluids microenvironment due to its specific mesoporous structure and large surface area. For these reasons, functional ions (e.g. lithium (Li), strontium (Sr), Copper (Cu) and Boron (B)) and drug/growth factors (e.g. dexamethasone, vascular endothelial growth factor (VEGF) and bone morphogenetic protein (BMP)) have been incorporated into MBG, which shows high loading efficiency and effective release. The release of therapeutic ions and drug/growth factors from MBG offers it multifunctional properties, such as improved osteogenesis, angiogenesis, anti-bacterial/cancer activity. However, there is no a systematic review about delivery of therapeutic ions and drugs/growth factors from MBG for the functional effect on the tissue regeneration despite that significant progress has been achieved in the past five years. Therefore, in this review, we mainly focused on the new advances for the functional effect of delivering therapeutic ions and drugs/growth factors on the ostegeogenesis, angiogenesis and antibacterial activity. It is expected that the review will offer new concept to develop multifunctional biomaterials for bone regeneration by the synergistic effect of therapeutic ions and drug/growth factors.

  2. Retention of insulin-like growth factor I bioactivity during the fabrication of sintered polymeric scaffolds.

    PubMed

    Clark, Amanda; Milbrandt, Todd A; Hilt, J Zach; Puleo, David A

    2014-04-01

    The use of growth factors in tissue engineering offers an added benefit to cartilage regeneration. Growth factors, such as insulin-like growth factor I (IGF-I), increase cell proliferation and can therefore decrease the time it takes for cartilage tissue to regrow. In this study, IGF-I was released from poly(lactic-co-glycolic acid) (PLGA) scaffolds that were designed to have a decreased burst release often associated with tissue engineering scaffolds. The scaffolds were fabricated from IGF-I-loaded PLGA microspheres prepared by a double emulsion (W1/O/W2) technique. The microspheres were then compressed, sintered at 49 °C and salt leached. The bioactivity of soluble IGF-I was verified after being heat treated at 37, 43, 45, 49 and 60 °C. Additionally, the bioactivity of IGF-I was confirmed after being released from the sintered scaffolds. The triphasic release lasted 120 days resulting in 20%, 55% and 25% of the IGF-I being released during days 1-3, 4-58 and 59-120, respectively. Seeding bone marrow cells directly onto the IGF-I-loaded scaffolds showed an increase in cell proliferation, based on DNA content, leading to increased glycosaminoglycan production. The present results demonstrated that IGF-I remains active after being incorporated into heat-treated scaffolds, further enhancing tissue regeneration possibilities.

  3. [Effects of crop tree release on stand growth and stand structure of Cunninghamia lanceolata plantation].

    PubMed

    Wu, Jian-qiang; Wang, Yi-xiang; Yang, Yi; Zhu, Ting-ting; Zhu, Xu-dan

    2015-02-01

    Crop trees were selected in a 26-year-old even-aged Cunninghamia lanceolata plantation in Lin' an, and compared in plots that were released and unreleased to examine growth and structure responses for 3 years after thinning. Crop tree release significantly increased the mean increments of diameter and volume of individual tree by 1.30 and 1.25 times relative to trees in control stands, respectively. The increments of diameter and volume of crop trees were significantly higher than those of general trees in thinning plots, crop trees and general trees in control plots, which suggested that the responses from different tree types to crop tree release treatment were different. Crop tree release increased the average distances of crop trees to the nearest neighboring trees, reducing competition among crop trees by about 68.2%. 3-year stand volume increment for thinning stands had no significant difference with that of control stands although the number of trees was only 81.5% of the control. Crop trees in thinned plots with diameters over than 14 cm reached 18.0% over 3 years, compared with 12.0% for trees without thinning, suggesting that crop tree release benefited the larger individual trees. The pattern of tree locations in thinning plots tended to be random, complying with the rule that tree distribution pattern changes with growth. Crop tree release in C. lanceolata plantation not only promoted the stand growth, but also optimized the stand structure, benefiting crop trees sustained rapid growth and larger diameter trees production.

  4. Growth factor involvement in tension-induced skeletal muscle growth

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman W.

    1987-01-01

    New muscle tissue culture techniques were developed to grow embryonic skeletal myofibers which are able to differentiate into more adultlike myofibers. Studies on mechanical simulation of cultured muscle cell growth will now be more directly applicable to mechanically-induced growth in adult muscle, and lead to better models for understanding muscle tissue atrophy caused by disuse in the microgravity of space.

  5. [Stem cells and growth factors in wound healing].

    PubMed

    Pikuła, Michał; Langa, Paulina; Kosikowska, Paulina; Trzonkowski, Piotr

    2015-01-02

    Wound healing is a complex process which depends on the presence of various types of cells, growth factors, cytokines and the elements of extracellular matrix. A wound is a portal of entry for numerous pathogens, therefore during the evolution wound healing process has formed very early, being critical for the survival of every individual. Stem cells, which give rise to their early descendants progenitor cells and subsequently differentiated cells, play a specific role in the process of wound healing. Among the most important cells which take part in wound healing the following cells need to be distinguished: epidermal stem cells, dermal precursor of fibroblasts, adipose-derived stem cells as well as bone marrow cells. The activity of these cells is strictly regulated by various growth factors, inter alia epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), transforming growth factor (TGF), vascular endothelial growth factor (VEGF). Any disorders in functioning of stem cells and biological activity of growth factors may lead to the defects in wound healing, for instance delayed wound healing or creation of hypertrophic scars. Therefore, knowledge concerning the mechanisms of wound healing is extremely essential from clinical point of view. In this review the current state of the knowledge of the role of stem cells and growth factors in the process of wound healing has been presented. Moreover, some clinical aspects of wound healing as well as the possibility of the therapy based on stem cells and growth factors have included.

  6. Transforming growth factor alpha and epidermal growth factor levels in normal human gastrointestinal mucosa.

    PubMed Central

    Cartlidge, S. A.; Elder, J. B.

    1989-01-01

    Acid soluble proteins from 23 samples of normal human gastrointestinal mucosa derived from four normal adult organ donors were extracted and subjected to specific radiommunoassays for transforming growth factor alpha (TGF alpha) and urogastrone epidermal growth factor (URO-EGF). All tissues were found to contain immunoreactive TGF alpha and levels ranged from 57 to 4,776 pg-1 wet weight of tissue. Although levels varied between tissue donors, the distribution of TGF alpha throughout the gastrointestinal tract appeared similar in all cases. URO-EGF levels were much lower (0-216 pg g-1 wet weight). TGF alpha levels in extracts of gastrointestinal mucosa from a 7-year-old female donor were higher and the observed distribution was markedly different from adult levels. URO-EGF was not detected in mucosal or submucosal tissue extracts from this patient. Further studies in juveniles are indicated. PMID:2803941

  7. Supramolecular Nanofibers Enhance Growth Factor Signaling by Increasing Lipid Raft Mobility

    SciTech Connect

    Newcomb, Christina J.; Sur, Shantanu; Lee, Sungsoo S.; Yu, Jeong Min; Zhou, Yan; Snead, Malcolm L.; Stupp, Samuel I.

    2016-04-12

    The nanostructures of self-assembling biomaterials have been previously designed to tune the release of growth factors in order to optimize biological repair and regeneration. We report here on the discovery that weakly cohesive peptide nanostructures in terms of intermolecular hydrogen bonding, when combined with low concentrations of osteogenic growth factor, enhance both BMP-2 and Wnt mediated signaling in myoblasts and bone marrow stromal cells, respectively. Conversely, analogous nanostructures with enhanced levels of internal hydrogen bonding and cohesion lead to an overall reduction in BMP-2 signaling. We propose that the mechanism for enhanced growth factor signaling by the nanostructures is related to their ability to increase diffusion within membrane lipid rafts. The phenomenon reported here could lead to new nanomedicine strategies to mediate growth factor signaling for translational targets.

  8. The effects of tissue sealants, platelet gels, and growth factors on wound healing.

    PubMed

    Brissett, Anthony E; Hom, David B

    2003-08-01

    The improved understanding of wound healing has resulted in the rapid expansion of tissue adhesives, platelet gels, and the use of growth factors. Tissue sealants have been used to close incisions, seal and secure skin flaps, as well as promote hemostasis. Platelet gels have multiple uses that take advantage of their inherent clot-forming ability as well as their potential to release growth factors. Recombinant platelet-derived growth factor has been studied extensively for the treatment of chronic dermal ulcers and shows promise in enhancing wound care. This article will address some recent advancements related to the expanding use of tissue sealants and growth factors to enhance wound healing within the head and neck area.

  9. Effect of sulodexide on plasma transforming growth factor-beta1 in healthy volunteers.

    PubMed

    Borawski, Jacek; Dubowski, Miroslaw; Pawlak, Krystyna; Mysliwiec, Michal

    2010-02-01

    It is unknown whether the glycosaminoglycan drug sulodexide interferes with transforming growth factor-beta1--a member of heparin-binding family and a potent regulator of human biology and diseases. Hence, a 2-week pilot study was performed in 11 healthy men. Sulodexide was initially administered intravenously in a single dose, then--orally for 12 days and--again intravenously on study completion. Initial injection had no effect on activated form of the growth factor measured in plasma after 10 and 120 min; no change was also observed after 120 min from drug ingestion on day 7. On final intravenous administration, the growth factor levels increased by almost 60% after 10 min and remained elevated; the 120-min levels directly correlated with sulodexide dosage. Baseline cytokine levels decreased during the 2-week trial by more than 50%. In conclusion, transforming growth factor-beta1 release and likely downregulation of its expression may constitute novel pharmacological effects of sulodexide.

  10. Mouse hypothalamic growth hormone-releasing hormone and somatostatin responses to probes of signal transduction systems.

    PubMed

    Sato, M; Downs, T R; Frohman, L A

    1993-01-01

    Signal transduction mechanisms involved in mouse growth hormone-releasing hormone (GRH) and somatostatin (SRIH) release were investigated using an in vitro perifusion system. Hypothalamic fragments were exposed to depolarizing agents, protein kinase A and C activators, and a calcium ionophore. The depolarizing agents, KCl (60 mM) and veratridine (50 microM), induced similar patterns of GRH and SRIH release. Somatostatin release in response to both agents was twofold greater than that of GRH. Forskolin (10 microM and 100 microM), an adenylate cyclase activator, stimulated both GRH and SRIH release, though with different secretory profiles. The SRIH response was prolonged and persisted beyond removal of the drug from the system, while the GRH response was brief, ending even prior to forskolin removal. Neither GRH nor SRIH were stimulated by 1,9-dideoxy-forskolin (100 microM), a forskolin analog with cAMP-independent actions. A23187 (5 microM), a calcium ionophore, stimulated the release of SRIH to a much greater extent than that of GRH. The GRH and SRIH secretory responses to PMA (1 microM), a protein kinase C activator, were similar, though delayed. The results suggest that 1) GRH and SRIH secretion are regulated by both protein kinase A and C pathways, and 2) depolarizing agents are important for the release of both hormones.

  11. Direct binding of hepatocyte growth factor and vascular endothelial growth factor to CD44v6.

    PubMed

    Volz, Yvonne; Koschut, David; Matzke-Ogi, Alexandra; Dietz, Marina S; Karathanasis, Christos; Richert, Ludovic; Wagner, Moritz G; Mély, Yves; Heilemann, Mike; Niemann, Hartmut H; Orian-Rousseau, Véronique

    2015-06-29

    CD44v6, a member of the CD44 family of transmembrane glycoproteins is a co-receptor for two receptor tyrosine kinases (RTKs), Met and VEGFR-2 (vascular endothelial growth factor receptor 2). CD44v6 is not only required for the activation of these RTKs but also for signalling. In order to understand the role of CD44v6 in Met and VEGFR-2 activation and signalling we tested whether CD44v6 binds to their ligands, HGF (hepatocyte growth factor) and VEGF (vascular endothelial growth factor), respectively. FACS analysis and cellular ELISA showed binding of HGF and VEGF only to cells expressing CD44v6. Direct binding of CD44v6 to HGF and VEGF was demonstrated in pull-down assays and the binding affinities were determined using MicroScale Thermophoresis, fluorescence correlation spectroscopy and fluorescence anisotropy. The binding affinity of CD44v6 to HGF is in the micromolar range in contrast with the high-affinity binding measured in the case of VEGF and CD44v6, which is in the nanomolar range. These data reveal a heparan sulfate-independent direct binding of CD44v6 to the ligands of Met and VEGFR-2 and suggest different roles of CD44v6 for these RTKs.

  12. [Growth factors in human tooth development].

    PubMed

    Bellone, C; Barni, T; Pagni, L; Balboni, G C; Vannelli, G B

    1990-03-01

    Our research concerns the immunohistochemical localization of EGF and IGF-I receptors in the tooth germ, using monoclonal antibodies. The results show that in the early phases of human tooth development EGF and IGF-I receptors are present. At bud stage both receptors are localized at dental laminae level, in some epithelial cells of the tooth bud and in some mesenchymal cells. At cap stage the receptors are present in the outer and inner enamel epithelium, and in some cells of stellate reticulum. As far as concerns the mesenchymal cells, some cells of dental papilla in contact with enamel organ, are intensely positive. The immunopositivity is present also in some mesenchymal cells at follicular level. At late cap stage and at early bell stage receptors are not present at inner enamel epithelium level but they can be detectable in the mesenchyma of dental papilla and in some cells of the follicle. On the basis of these results it may be hypothesized that EGF and IGF-I can act as growth factors in the modulation of cellular proliferation and differentiation during the human tooth morphogenesis. Moreover, it is possible that these substances can play a role in the mesenchymal-epithelial interaction in the developing human tooth.

  13. Nerve growth factor enhances sleep in rabbits.

    PubMed

    Takahashi, S; Krueger, J M

    1999-04-02

    Nerve growth factor (NGF) elicits rapid-eye-movement sleep (REMS) in cats. Removal of NGF receptor-positive cholinergic basal forebrain neurons inhibits REMS in rats. The aim of the present study was to determine the effects of NGF on sleep and brain temperature (Tbr) in rabbits. Male rabbits were implanted with electroencephalograph (EEG) electrodes, a brain thermistor and an intraventricular (i.c.v.) guide cannula. Rabbits received human beta-NGF i.c.v. (0.01, 0.1, 1.0 or 10 microg] and on a separate day, 25 microl pyrogen-free saline i.c.v. as control. EEG and Tbr were recorded for 23 h after injections. The highest two doses of NGF increased both non-REMS and REMS across the 23-h recording period. REMS was enhanced dose-dependently. Tbr was not affected by any dose of NGF. These results suggest that NGF is involved in both REMS and non-REMS regulation.

  14. Transforming growth factor beta1 and aldosterone

    PubMed Central

    Matsuki, Kota; Hathaway, Catherine K.; Chang, Albert S.; Smithies, Oliver; Kakoki, Masao

    2016-01-01

    Purpose of review It is well established that blocking renin-angiotensin II-aldosterone system (RAAS) is effective for the treatment of cardiovascular and renal complications in hypertension and diabetes mellitus. Although the induction of transforming growth factor beta1 (TGFbeta1) by components of RAAS mediates the hypertrophic and fibrogenic changes in cardiovascular-renal complications, it is still controversial as to whether TGFbeta1 can be a target to prevent such complications. Here we review recent findings on the role of TGFbeta1 in fluid homeostasis, focusing on the relationship with aldosterone. Recent findings TGFbeta1 suppresses adrenal production of aldosterone and renal tubular sodium reabsorption. We have generated mice with TGFbeta1 mRNA expression graded in five steps from 10% to 300% normal, and found that blood pressure and plasma volume are negatively regulated by TGFbeta1. Notably, the 10 % hypomorph exhibits primary aldosteronism and sodium and water retention due to markedly impaired urinary excretion of water and electrolytes. Summary These results identify TGFbeta signaling as an important counterregulatory system against aldosterone. Understanding the molecular mechanisms for the suppressive effects of TGFbeta1 on adrenocortical and renal function may further our understanding of primary aldosteronism as well as assist in the development of novel therapeutic strategies for hypertension. PMID:25587902

  15. Vascular Endothelial Growth Factor in Eye Disease

    PubMed Central

    Penn, J.S.; Madan, A.; Caldwell, R.B.; Bartoli, M.; Caldwell, R.W.; Hartnett, M.E.

    2012-01-01

    Collectively, angiogenic ocular conditions represent the leading cause of irreversible vision loss in developed countries. In the U.S., for example, retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration are the principal causes of blindness in the infant, working age and elderly populations, respectively. Evidence suggests that vascular endothelial growth factor (VEGF), a 40 kDa dimeric glycoprotein, promotes angiogenesis in each of these conditions, making it a highly significant therapeutic target. However, VEGF is pleiotropic, affecting a broad spectrum of endothelial, neuronal and glial behaviors, and confounding the validity of anti-VEGF strategies, particularly under chronic disease conditions. In fact, among other functions VEGF can influence cell proliferation, cell migration, proteolysis, cell survival and vessel permeability in a wide variety of biological contexts. This article will describe the roles played by VEGF in the pathogenesis of retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration. The potential disadvantages of inhibiting VEGF will be discussed, as will the rationales for targeting other VEGF-related modulators of angiogenesis. PMID:18653375

  16. [Epidermal growth factor, innovation and safety].

    PubMed

    Esquirol Caussa, Jordi; Herrero Vila, Elisabeth

    2015-10-05

    Bioidentical recombinant human epidermal growth factor (rhEGF) is available in concentrations and purity suitable for therapeutic use in long time stable formulations. Beneficial effects in several skin pathologies and lesions have been reported (traumatic and surgical wound healing, laser induced wounds, abnormal scars, keloids, radiation or chemotherapy induced dermatitis, post inflammatory hyperpigmentation or for skin aging damage repairing) and also may be considered for the treatment of several oropharingeal and high gastroesophageal tract mucosa diseases (mouth sores, pharyngeal fistulas, ulcers), and several corneal or conjunctive mucosa lesions. rhEGF has not shown any important side or collateral effects in humans or in laboratory experimentation animals, showing optimal tolerability and safety with continuous use for months. Compounding gives advantages of versatility, individualization, personalization, molecular stability, safety and effectiveness in ideal conditions, showing good tissue penetration, both on intact skin and skin lesions that expose the lower planes to the surface. rhEGF compounds can be considered for prevention or as a treatment of diverse skin and mucosa diseases and conditions through compounding preparations.

  17. Growth Hormone-Insulin-Like Growth Factor Axis, Thyroid Axis, Prolactin, and Exercise.

    PubMed

    Hackney, Anthony C; Davis, Hope C; Lane, Amy R

    2016-01-01

    This chapter addresses what is known about the endocrine system components growth hormone (GH)-insulin-like growth factor (IGF) axis, thyroid axis, and prolactin relative to exercise and exercise training. Each one of these hormone axes contributes to the maintenance of homeostasis in the body through impact on a multitude of physiological systems. The homeostatic disruption of exercise causes differing responses in each hormone axis. GH levels increase with sufficient stimulation, and IGFs are released in response to GH from the anterior pituitary providing multiple roles including anabolic properties. Changes in the thyroid hormones T3 and T4 vary greatly with exercise, from increases/decreases to no change in levels across different exercise types, intensities and durations. These ambiguous findings could be due to numerous confounding factors (e.g. nutrition status) within the research. Prolactin increases proportionally to the intensity of the exercise. The magnitude may be augmented with extended durations; conflicting findings have been reported with resistance training. While the responses to exercise vary, it appears there may be overall adaptive and regenerative impacts on the body into recovery by these hormones through immune and tissue inflammatory responses/mediations. Nonetheless, well-designed exercise research studies are still needed on each of these hormones, especially thyroid hormones and prolactin.

  18. The promotion of angiogenesis by growth factors integrated with ECM proteins through coiled-coil structures.

    PubMed

    Assal, Yasmine; Mie, Masayasu; Kobatake, Eiry

    2013-04-01

    An appropriate method to bind extracellular matrix (ECM) proteins and growth factors using advanced protein engineering techniques has the potential to enhance cell proliferation and differentiation for tissue regeneration and repair. In this study we developed a method to co-immobilize non-covalently an ECM protein to three different types of growth factors: basic fibroblast growth factor (bFGF), epidermal growth factor (EGF) and single-chain vascular endothelial growth factor (scVEGF121) through a coiled-coil structure formed by helixA/helixB in order to promote angiogenesis. The designed ECM was established by fusing two repeats of elastin-derived unit (APGVGV)(12), cell-adhesive sequence (RGD), laminin-derived IKVAV sequence and collagen-binding domain (CBD) to obtain CBDEREI2. HelixA was fused to each growth factor and helixB to the engineered ECM. Human umbilical vein endothelial cells (HUVECs) were cultured on engineered ECM and growth factors connected through the coiled-coil formation between helixA and helixB. Cell proliferation and capillary tube-like formation were monitored. Moreover, the differentiated cells with high expression of Ang-2 suggested the ECM remodeling. Our approach of non-covalent coupling method should provide a protein-release control system as a new contribution in biomaterial for tissue engineering field.

  19. Collagen and Stretch Modulate Autocrine Secretion of Insulin-like Growth Factor-1 and Insulin-like Growth Factor Binding Proteins from Differentiated Skeletal Muscle Cells

    NASA Technical Reports Server (NTRS)

    Perrone, Carmen E.; Fenwick-Smith, Daniela; Vandenburgh, Herman H.

    1995-01-01

    Stretch-induced skeletal muscle growth may involve increased autocrine secretion of insulin-like growth factor-1 (IGF-1) since IGF-1 is a potent growth factor for skeletal muscle hypertrophy, and stretch elevates IGF-1 mRNA levels in vivo. In tissue cultures of differentiated avian pectoralis skeletal muscle cells, nanomolar concentrations of exogenous IGF-1 stimulated growth in mechanically stretched but not static cultures. These cultures released up to 100 pg of endogenously produced IGF-1/micro-g of protein/day, as well as three major IGF binding proteins of 31, 36, and 43 kilodaltons (kDa). IGF-1 was secreted from both myofibers and fibroblasts coexisting in the muscle cultures. Repetitive stretch/relaxation of the differentiated skeletal muscle cells stimulated the acute release of IGF-1 during the first 4 h after initiating mechanical activity, but caused no increase in the long-term secretion over 24-72 h of IGF-1, or its binding proteins. Varying the intensity and frequency of stretch had no effect on the long-term efflux of IGF-1. In contrast to stretch, embedding the differentiated muscle cells in a three-dimensional collagen (Type I) matrix resulted in a 2-5-fold increase in long-term IGF-1 efflux over 24-72 h. Collagen also caused a 2-5-fold increase in the release of the IGF binding proteins. Thus, both the extracellular matrix protein type I collagen and stretch stimulate the autocrine secretion of IGF-1, but with different time kinetics. This endogenously produced growth factor may be important for the growth response of skeletal myofibers to both types of external stimuli.

  20. Risk factors for hazardous substance releases that result in injuries and evacuations: data from 9 states.

    PubMed Central

    Hall, H I; Haugh, G S; Price-Green, P A; Dhara, V R; Kaye, W E

    1996-01-01

    This study was undertaken to determine risk factors associated with hazardous substance releases (at fixed facilities or during transport) that have public health consequences. Data from nine states with surveillance systems for such releases and their consequences were analyzed. Risk factors were determined for releases resulting in (1) injuries or (2) evacuations. Both outcomes were more likely to occur as a result of facility releases (odds ratio [OR] = 1.89, 95% confidence interval [CI] = 1.44, 2.47, for injuries; OR = 3.29, 95% CI = 2.28, 4.74, for evacuations). Releases of ammonia, chlorine, and acids resulted in injuries and evacuations more frequently than releases of other substances. PMID:8659662

  1. [Periodontal regeneration: the use of polypeptide growth factors].

    PubMed

    Di Genio, M; Barone, A; Ramaglia, L; Sbordone, L

    1994-10-01

    Polypeptide growth factors are a class of potent natural biologic mediators which regulate many of the activities of wound healing including cell proliferation, migration and metabolism. Periodontal regeneration is thought to require the migration and proliferation of periodontal ligament cells on the root surface. In fact, repopulation of the detached root surface by cells from periodontal ligament (PDL) is a prerequisite for new attachment formation. Many studies suggested that Polypeptide Growth Factors (PGF) such as Insulin-like Growth Factor I (IGF-I), Platelet Derived Growth Factor (PDGF), Transforming Growth Factor B (TGF-B), Epidermal Growth Factor (EGF), are important mediators of cellular events in wound healing. Studies in vitro analysed the mitogenic effects determined on periodontal ligament cells by growth factors using (3H) Thymidine incorporation during DNA synthesis. The results suggested that recombinant human PDGF and IGF-I stimulate the proliferation of PDL fibroblastic cells and the combination of these growth factors showed a synergistic effect revealing the highest mitogenic effect among all individual growth factors as well as any combination of the growth factors tested. Furthermore these studies demonstrated that rh-PDGF and IGF-I stimulate chemotaxis of PDL fibroblastic cells, and supported a role for TGF-B as a regulator of the mitogenic response to PDGF in these cells. Other studies in vivo showed periodontal tissues regeneration introducing mixtures of recombinant human platelet derived growth factor and insulin-like growth factor into lesions of experimentally induced periodontitis in beagle dogs and monkeys.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Acoustic droplet–hydrogel composites for spatial and temporal control of growth factor delivery and scaffold stiffness

    PubMed Central

    Fabiilli, Mario L.; Wilson, Christopher G.; Padilla, Frédéric; Martín-Saavedra, Francisco M.; Fowlkes, J. Brian; Franceschi, Renny T.

    2013-01-01

    Wound healing is regulated by temporally and spatially restricted patterns of growth factor signaling, but there are few delivery vehicles capable of the “on-demand” release necessary for recapitulating these patterns. Recently we described a perfluorocarbon double emulsion that selectively releases a protein payload upon exposure to ultrasound through a process known as acoustic droplet vaporization (ADV). In this study, we describe a delivery system composed of fibrin hydrogels doped with growth factor-loaded double emulsion for applications in tissue regeneration. Release of immunoreactive basic fibroblast growth factor (bFGF) from the composites increased up to 5-fold following ADV and delayed release was achieved by delaying exposure to ultrasound. Releasates of ultrasound-treated materials significantly increased the proliferation of endothelial cells compared to sham controls, indicating that the released bFGF was bioactive. ADV also triggered changes in the ultrastructure and mechanical properties of the fibrin as bubble formation and consolidation of the fibrin in ultrasound-treated composites were accompanied by up to a 22-fold increase in shear stiffness. ADV did not reduce the viability of cells suspended in composite scaffolds. These results demonstrate that an acoustic droplet–hydrogel composite could have broad utility in promoting wound healing through on-demand control of growth factor release and/or scaffold architecture. PMID:23535233

  3. Nerve growth factor gene therapy in Alzheimer disease.

    PubMed

    Tuszynski, Mark H

    2007-01-01

    Nervous system growth factors potently stimulate cell function and prevent neuronal death. These broad effects on survival and function arise from direct downstream activation of antiapoptotic pathways, inhibition of proapoptotic pathways, and stimulation of functionally important cellular mechanisms including ERK/MAP kinase and CREB. Thus, as a class, growth factors offer the potential to treat neurodegenerative disorders for the first time by preventing neuronal degeneration rather than compensating for cell loss after it has occurred. Different growth factors affect distinct and specific populations of neurons: the first nervous system growth factor identified, nerve growth factor, potentially stimulates the survival and function of basal forebrain cholinergic neurons, suggesting that nerve growth factor could be a means for reducing the cholinergic component of cell degeneration in Alzheimer disease. This review will discuss the transition of growth factors from preclinical studies to human clinical trials in Alzheimer disease. The implementation of clinical testing of growth factor therapy for neurologic disease has been constrained by the dual need to achieve adequate concentrations of these proteins in specific brain regions containing degenerating neurons, and preventing growth factor spread to nontargeted regions to avoid adverse effects. Gene therapy is one of a limited number of potential methods for achieving these requirements.

  4. Platelet-aggregating activity of released factor(s) from Trypanosoma brucei brucei.

    PubMed

    Nwagwu, M; Inyang, A L; Molokwu, R I; Essien, E M

    1989-12-01

    The effect of factors derived from Trypanosoma brucei brucei on rat platelets was studied. T. brucei at a concentration of 4 X 10(9) trypanosomes/ml phosphate saline glucose (PSG) was stored at -20 degrees C for 18 h, thawed, and a supernatant fraction, trypanosome-derived supernatant (TDS) was obtained by spinning the sample at 3000 g for 10 min at 20 degrees C. Normal rat platelets, prepared as platelet-rich plasma (PRP), were then incubated with TDS in the absence or presence of ADP (0.05-0.1 microM). The results showed that approximately 83% platelet aggregation was induced by addition of TDS (50 microliters; 113 micrograms protein) to 100 microliters PRP with a platelet count of 10(6). simultaneous addition of ADP and TDS to PRP produced a synergistic effect. It was also shown that a supernatant fraction, obtained by incubating live T. brucei (4 X 10(9)/microliters PSG) at 0 degrees C 1 h and spinning down the trypanosomes (3000 g for 10 min), also induced platelet aggregation. The nature of the factor(s) derived from, or released by, T. brucei inducing platelet aggregation is being investigated but it has been shown not to be ADP.

  5. Transforming growth factor-β and Smads.

    PubMed

    Lan, Hui Yao; Chung, Arthur C K

    2011-01-01

    Diabetic nephropathy (DN) is a major diabetic complication. Transforming growth factor-β(TGF-β) is a key mediator in the development of diabetic complications. It is well known that TGF-β exerts its biological effects by activating downstream mediators, called Smad2and Smad3, which is negatively regulated by an inhibitory Smad7. Recent studies also demonstrated that under disease conditions Smads act as signal integrators and interact with other signaling pathways such as the MAPK and NF-κB pathways. In addition, Smad2and Smad3 can reciprocally regulate target genes of TGF-β signaling. Novel research into microRNA has revealed the complexity of TGF-β signaling during DN. It has been found that TGF-β and elevated glucose concentration can positively regulate miR-192 and miR-377, but negatively regulate miR-29a in a diabetic milieu. These microRNAs are found to contribute to DN. Although targeting TGF-β may exert adverse effects on immune system, therapeutic approach against TGF-β signaling during DN still draws much attention. Blocking TGF-β signaling by neutralizing antibody, anti-sense oligonucleotides, and soluble receptors have been tested, but effects are limited. Gene transfer of Smad7 into diseased kidneys demonstrates a prominent inhibition on renal fibrosis and amelioration of renal impairment. Alteration of TGF-β-regulated microRNA expression in diseased kidneys may provide an alternative therapeutic approach against DN. In conclusion, TGF-β/Smad signaling plays a critical role in DN. A better understanding of the role of TGF-β/Smad signaling in the development of DN should provide an effective therapeutic strategy to combat DN.

  6. Fibroblast Growth Factor Signaling in Metabolic Regulation

    PubMed Central

    Nies, Vera J. M.; Sancar, Gencer; Liu, Weilin; van Zutphen, Tim; Struik, Dicky; Yu, Ruth T.; Atkins, Annette R.; Evans, Ronald M.; Jonker, Johan W.; Downes, Michael Robert

    2016-01-01

    The prevalence of obesity is a growing health problem. Obesity is strongly associated with several comorbidities, such as non-alcoholic fatty liver disease, certain cancers, insulin resistance, and type 2 diabetes, which all reduce life expectancy and life quality. Several drugs have been put forward in order to treat these diseases, but many of them have detrimental side effects. The unexpected role of the family of fibroblast growth factors in the regulation of energy metabolism provides new approaches to the treatment of metabolic diseases and offers a valuable tool to gain more insight into metabolic regulation. The known beneficial effects of FGF19 and FGF21 on metabolism, together with recently discovered similar effects of FGF1 suggest that FGFs and their derivatives carry great potential as novel therapeutics to treat metabolic conditions. To facilitate the development of new therapies with improved targeting and minimal side effects, a better understanding of the molecular mechanism of action of FGFs is needed. In this review, we will discuss what is currently known about the physiological roles of FGF signaling in tissues important for metabolic homeostasis. In addition, we will discuss current concepts regarding their pharmacological properties and effector tissues in the context of metabolic disease. Also, the recent progress in the development of FGF variants will be reviewed. Our goal is to provide a comprehensive overview of the current concepts and consensuses regarding FGF signaling in metabolic health and disease and to provide starting points for the development of FGF-based therapies against metabolic conditions. PMID:26834701

  7. Mesocosm experiments to assess factors affecting phosphorus retention and release in an extended Wisconsin wetland

    USGS Publications Warehouse

    Elder, J.F.; Manion, B.J.; Goddard, G.L.

    1997-01-01

    Phosphorus retention by wetland sediments and vegetation was investigated in Jackson Creek wetland, an extension of an existing prairie marsh in southeastern Wisconsin. The extended wetland construction was undertaken in 1992-93 to help reduce the phosphorus loading to a downstream eutrophic lake. Two approaches were used to study potential and actual phosphorus retention in the system. Mesocosm experiments of 20-40 days duration indicated that retention of total and dissolved reactive phosphorus in mesocosm cells containing macrophytes and/or sediments was reduced by factors of 2-20 relative to cells containing only water or a copper algicide to suppress metabolic activity. In contrast to the nutrient trapping function, these results show a potential for net phosphorus release that can be associated with increased biological richness. Measurements of water flow and nutrient loads at the wetland's inflow and outflow points demonstrated 9-39% net uptake of phosphorus on an annual scale but frequent occurrences of net phosphorus release over shorter (one-month) time scales. These episodes of release are most likely during the summer months. Thus, the wetland role in phosphorus cycling is not one of a true source or sink, although the annual budget data alone suggest substantial net retention. Effective management of the wetland for its nutrient trapping potential can be hindered by this oversimplification. The system is instead subject to relatively short-term alternation between net import and export. The periodic phosphorus export, although representing a small fraction of net annual import, could be critical for growth of macrophyte and algal communities downstream.

  8. The sludge loading rate regulates the growth and release of heterotrophic bacteria resistant to six types of antibiotics in wastewater activated sludge.

    PubMed

    Yuan, Qing-Bin; Guo, Mei-Ting; Yang, Jian

    2015-01-01

    Wastewater treatment plants are considered as hot reservoirs of antimicrobial resistance. However, the fates of antibiotic-resistant bacteria during biological treatment processes and relevant influencing factors have not been fully understood. This study evaluated the effects of the sludge loading rate on the growth and release of six kinds of antibiotic-resistant bacteria in an activated sludge system. The results indicated that higher sludge loading rates amplified the growth of all six types of antibiotic resistant bacteria. The release of most antibiotic-resistant bacteria through both the effluent and biosolids was amplified with increased sludge loading rate. Biosolids were the main pattern for all antibiotic-resistant bacteria release in an activated sludge system, which was determined primarily by their growth in the activated sludge. A higher sludge loading rate reactor tended to retain more antibiotic resistance. An activated sludge system with lower sludge loading rates was considered more conducive to the control of antibiotic resistance.

  9. FACTORS RELATING TO THE RELEASE OF STACHYBOTRYS CHARTARUM SPORES FROM CONTAMINATED SOURCES

    EPA Science Inventory

    The paper describes preliminary results of a research project to determine the factors that control the release of S. chartarum spores from a contaminated source and test ways to reduce spore release and thus exposure. As anticipated, S. chartarum spore emissions from gypsum boar...

  10. Adaptive growth factor delivery from a polyelectrolyte coating promotes synergistic bone tissue repair and reconstruction

    PubMed Central

    Shah, Nisarg J.; Hyder, Md. Nasim; Quadir, Mohiuddin A.; Dorval Courchesne, Noémie-Manuelle; Seeherman, Howard J.; Nevins, Myron; Spector, Myron; Hammond, Paula T.

    2014-01-01

    Traumatic wounds and congenital defects that require large-scale bone tissue repair have few successful clinical therapies, particularly for craniomaxillofacial defects. Although bioactive materials have demonstrated alternative approaches to tissue repair, an optimized materials system for reproducible, safe, and targeted repair remains elusive. We hypothesized that controlled, rapid bone formation in large, critical-size defects could be induced by simultaneously delivering multiple biological growth factors to the site of the wound. Here, we report an approach for bone repair using a polyelectrolye multilayer coating carrying as little as 200 ng of bone morphogenetic protein-2 and platelet-derived growth factor-BB that were eluted over readily adapted time scales to induce rapid bone repair. Based on electrostatic interactions between the polymer multilayers and growth factors alone, we sustained mitogenic and osteogenic signals with these growth factors in an easily tunable and controlled manner to direct endogenous cell function. To prove the role of this adaptive release system, we applied the polyelectrolyte coating on a well-studied biodegradable poly(lactic-co-glycolic acid) support membrane. The released growth factors directed cellular processes to induce bone repair in a critical-size rat calvaria model. The released growth factors promoted local bone formation that bridged a critical-size defect in the calvaria as early as 2 wk after implantation. Mature, mechanically competent bone regenerated the native calvaria form. Such an approach could be clinically useful and has significant benefits as a synthetic, off-the-shelf, cell-free option for bone tissue repair and restoration. PMID:25136093

  11. The cauliflower Orange gene enhances petiole elongation by suppressing expression of eukaryotic release factor 1.

    PubMed

    Zhou, Xiangjun; Sun, Tian-Hu; Wang, Ning; Ling, Hong-Qing; Lu, Shan; Li, Li

    2011-04-01

    The cauliflower (Brassica oleracea var. botrytis) Orange (Or) gene affects plant growth and development in addition to conferring β-carotene accumulation. This study was undertaken to investigate the molecular basis for the effects of the Or gene mutation in on plant growth. The OR protein was found to interact with cauliflower and Arabidopsis eukaryotic release factor 1-2 (eRF1-2), a member of the eRF1 family, by yeast two-hybrid analysis and by bimolecular fluorescence complementation (BiFC) assay. Concomitantly, the Or mutant showed reduced expression of the BoeRF1 family genes. Transgenic cauliflower plants with suppressed expression of BoeRF1-2 and BoeRF1-3 were generated by RNA interference. Like the Or mutant, the BoeRF1 RNAi lines showed increased elongation of the leaf petiole. This long-petiole phenotype was largely caused by enhanced cell elongation, which resulted from increased cell length and elevated expression of genes involved in cell-wall loosening. These findings demonstrate that the cauliflower Or gene controls petiole elongation by suppressing the expression of eRF1 genes, and provide new insights into the molecular mechanism of leaf petiole regulation.

  12. Effects of retinoic acid on growth hormone-releasing hormone receptor, growth hormone secretagogue receptor gene expression and growth hormone secretion in rat anterior pituitary cells.

    PubMed

    Maliza, Rita; Fujiwara, Ken; Tsukada, Takehiro; Azuma, Morio; Kikuchi, Motoshi; Yashiro, Takashi

    2016-06-30

    Retinoic acid (RA) is an important signaling molecule in embryonic development and adult tissue. The actions of RA are mediated by the nuclear receptors retinoic acid receptor (RAR) and retinoid X receptor (RXR), which regulate gene expression. RAR and RXR are widely expressed in the anterior pituitary gland. RA was reported to stimulate growth hormone (GH) gene expression in the anterior pituitary cells. However, current evidence is unclear on the role of RA in gene expression of growth hormone-releasing hormone receptor (Ghrh-r), growth hormone secretagogue receptor (Ghs-r) and somatostatin receptors (Sst-rs). Using isolated anterior pituitary cells of rats, we examined the effects of RA on gene expression of these receptors and GH release. Quantitative real-time PCR revealed that treatment with all-trans retinoic acid (ATRA; 10(-6) M) for 24 h increased gene expression levels of Ghrh-r and Ghs-r; however, expressions of Sst-r2 and Sst-r5 were unchanged. Combination treatment with the RAR-agonist Am80 and RXR-agonist PA024 mimicked the effects of ATRA on Ghrh-r and Ghs-r gene expressions. Exposure of isolated pituitary cells to ATRA had no effect on basal GH release. In contrast, ATRA increased growth hormone-releasing hormone (GHRH)- and ghrelin-stimulated GH release from cultured anterior pituitary cells. Our results suggest that expressions of Ghrh-r and Ghs-r are regulated by RA through the RAR-RXR receptor complex and that RA enhances the effects of GHRH and ghrelin on GH release from the anterior pituitary gland.

  13. Protective Factors for Violence among Released Prisoners--Effects over Time and Interactions with Static Risk

    ERIC Educational Resources Information Center

    Ullrich, Simone; Coid, Jeremy

    2011-01-01

    Objective: There is a substantial body of research on risk factors for violent behavior in adulthood but little empirical study of protective factors and desistance. Method: This study aimed to investigate the protective effects of factors hypothesized to reduce violent reoffending among a sample of 800 male prisoners following release into the…

  14. Effects of epidermal growth factor on neural crest cells in tissue culture

    SciTech Connect

    Erickson, C.A.; Turley, E.A.

    1987-04-01

    Epidermal growth factor (EGF) stimulates the release of hyaluronic acid (HA) and chondroitin sulfate proteoglycan (CSPG) from quail trunk neural crest cultures in a dose-dependent fashion. It also promotes the expression of cell-associated heparan sulfate proteoglycan (HSPG) as detected by immunofluorescence and immunoprecipitation of the /sup 3/H-labeled proteoglycan. Furthermore, EGF stimulates (/sup 3/H)thymidine incorporation into total cell DNA. These results raise the possibility that EGF or an analogous growth factor is involved in regulation of neural crest cell morphogenesis.

  15. Connective tissue growth factor is a substrate of ADAM28

    SciTech Connect

    Mochizuki, Satsuki; Tanaka, Rena; Shimoda, Masayuki; Onuma, Junko; Fujii, Yutaka; Jinno, Hiromitsu; Okada, Yasunori

    2010-11-26

    Research highlights: {yields} The hyper-variable region in the cysteine-rich domain of ADAM28 binds to C-terminal domain of CTGF. {yields} ADAM28 cleaves CTGF alone and CTGF in the CTGF/VEGF{sub 165} complex. {yields} CTGF digestion by ADAM28 releases biologically active VEGF{sub 165} from the complex. {yields} ADAM28, CTGF and VEGF{sub 165} are commonly co-expressed by carcinoma cells in human breast carcinoma tissues. {yields} These suggest that ADAM28 promotes VEGF{sub 165}-induced angiogenesis in the breast carcinomas by selective CTGF digestion in the CTGF/VEGF{sub 165} complex. -- Abstract: ADAM28, a member of the ADAM (a disintegrin and metalloproteinase) gene family, is over-expressed by carcinoma cells and the expression correlates with carcinoma cell proliferation and progression in human lung and breast carcinomas. However, information about substrates of ADAM28 is limited. We screened interacting molecules of ADAM28 in human lung cDNA library by yeast two-hybrid system and identified connective tissue growth factor (CTGF). Binding of CTGF to proADAM28 was demonstrated by yeast two-hybrid assay and protein binding assay. ADAM28 cleaved CTGF in dose- and time-dependent manners at the Ala{sup 181}-Tyr{sup 182} and Asp{sup 191}-Pro{sup 192} bonds in the hinge region of the molecule. ADAM28 selectively digested CTGF in the complex of CTGF and vascular endothelial growth factor{sub 165} (VEGF{sub 165}), releasing biologically active VEGF{sub 165} from the complex. RT-PCR and immunohistochemical analyses demonstrated that ADAM28, CTGF and VEGF are commonly co-expressed in the breast carcinoma tissues. These data provide the first evidence that CTGF is a novel substrate of ADAM28 and suggest that ADAM28 may promote VEGF{sub 165}-induced angiogenesis in the breast carcinomas by the CTGF digestion in the CTGF/VEGF{sub 165} complex.

  16. Endogenous growth hormone (GH)-releasing hormone is required for GH responses to pharmacological stimuli.

    PubMed Central

    Jaffe, C A; DeMott-Friberg, R; Barkan, A L

    1996-01-01

    The roles of hypothalamic growth hormone-releasing hormone (GHRH) and of somatostatin (SRIF) in pharmacologically stimulated growth hormone (GH) secretion in humans are unclear. GH responses could result either from GHRH release or from acute decline in SRIF secretion. To assess directly the role of endogenous GHRH in human GH secretion, we have used a competitive GHRH antagonist, (N-Ac-Tyr1,D-Arg2)GHRH(1-29)NH2 (GHRH-Ant), which we have previously shown is able to block the GH response to GHRH. We first tested whether an acute decline in SRIF, independent of GHRH action, would release GH. Pretreatment with GHRH-Ant abolished the GH response to exogenous GHRH (0.33 microgram/kg i.v.) but did not modify the GH rise after termination of an SRIF infusion. We then investigated the role of endogenous GHRH in the GH responses to pharmacologic stimuli of GH release. The GH responses to arginine (30 g i.v. over 30 min), L-dopa (0.5 g orally), insulin hypoglycemia (0.1 U/Kg i.v.), clonidine (0.25 mg orally), or pyridostigmine (60 mg orally) were measured in healthy young men after pretreatment with either saline of GHRH-Ant 400 microgram/kg i.v. In every case, GH release was significantly suppressed by GHRH-Ant. We conclude that endogenous GHRH is required for the GH response to each of these pharmacologic stimuli. Acute release of hypothalamic GHRH may be a common mechanism by which these compounds mediate GH secretion. PMID:8613546

  17. Heparin-conjugated poly(lactic-co-glycolic acid) nanospheres enhance large-wound healing by delivering growth factors in platelet-rich plasma.

    PubMed

    La, Wan-Geun; Yang, Hee Seok

    2015-04-01

    Platelet-rich plasma (PRP) contains many growth factors that are involved in tissue regeneration processes. For successful tissue regeneration, protein growth factors require a delivery vehicle for long-term and sustained release to a defect site in order to maintain their bioactivity. Previously, we showed that heparin-conjugated poly(lactic-co-glycolic acid) nanospheres (HCPNs) can provide long-term delivery of growth factors with affinity for heparin. In this study, we hypothesize that treatment of a skin wound with a mixture of PRP and HCPNs would provide long-term delivery of several growth factors contained in PRP to promote the skin wound healing process with preservation of bioactivity. The release of platelet-derived growth factor-BB (PDGF-BB), contained in PRP, from HCPN with fibrin gel (FG) showed a prolonged release period versus a PRP mixture with FG alone (FG-PRP). Also, growth factors released from PRP with HCPN and FG showed sustained human dermal fibroblast growth for 12 days. Full-thickness skin wound treatment in mice with FG-HCPN-PRP resulted in much faster wound closure as well as dermal and epidermal regeneration at day 9 compared with treatment with FG-HCPN or FG-PRP. The enhanced wound healing using FG-HCPN-PRP may be due to the prolonged release not only of PDGF-BB but also of other growth factors in the PRP. The delivered growth factors accelerated angiogenesis at the wound site.

  18. [Effects of applying controlled-release compound fertilizer on Platycodon grandiflorum growth].

    PubMed

    Zhu, Li-xiang; Wang, Jian-hua

    2010-09-01

    A pot experiment was conducted in 2008 to study the effects of applying controlled-release compound fertilizer (N:P2O5:K2O = 14:14:14) on the growth of Platycodon grandiflorum in the medicinal herbal farm of Shandong Agricultural University. Comparing with the application of common compound fertilizer (N:P2O5: K2O=15: 15: 15), applying equivalent amount of the controlled-release fertilizer increased the leaf chlorophyll content, root volume, root activity, and root diameter of P. grandiflorum at the late growth stage, but decreased the root length. When the N application rate was 0.24 and 0.32 g x kg(-1) soil, applying the controlled-release compound fertilizer increased the root yield by 26.78% and 22.50%, and the root soluble sugar, protein, and total saponin contents by 9.77% and 6.99%, 11.38% and 2.20%, and 8.85% and 5.47%, respectively, compared with applying the common compound fertilizer. More nitrogen application made the root soluble sugar content decreased but the total saponin content increased. Under our experimental condition, applying the controlled-release compound fertilizer with an application rate of 0.24 g N x kg(-1) soil could obtain the best effect for P. grandiflorum.

  19. Growth factor- and cytokine-stimulated endothelial progenitor cells in post-ischemic cerebral neovascularization

    PubMed Central

    Peplow, Philip V.

    2014-01-01

    Endothelial progenitor cells are resident in the bone marrow blood sinusoids and circulate in the peripheral circulation. They mobilize from the bone marrow after vascular injury and home to the site of injury where they differentiate into endothelial cells. Activation and mobilization of endothelial progenitor cells from the bone marrow is induced via the production and release of endothelial progenitor cell-activating factors and includes specific growth factors and cytokines in response to peripheral tissue hypoxia such as after acute ischemic stroke or trauma. Endothelial progenitor cells migrate and home to specific sites following ischemic stroke via growth factor/cytokine gradients. Some growth factors are less stable under acidic conditions of tissue ischemia, and synthetic analogues that are stable at low pH may provide a more effective therapeutic approach for inducing endothelial progenitor cell mobilization and promoting cerebral neovascularization following ischemic stroke. PMID:25317152

  20. A bioactive molecule in a complex wound healing process: platelet-derived growth factor.

    PubMed

    Kaltalioglu, Kaan; Coskun-Cevher, Sule

    2015-08-01

    Wound healing is considered to be particularly important after surgical procedures, and the most important wounds related to surgical procedures are incisional, excisional, and punch wounds. Research is ongoing to identify methods to heal non-closed wounds or to accelerate wound healing; however, wound healing is a complex process that includes many biological and physiological events, and it is affected by various local and systemic factors, including diabetes mellitus, infection, ischemia, and aging. Different cell types (such as platelets, macrophages, and neutrophils) release growth factors during the healing process, and platelet-derived growth factor is a particularly important mediator in most stages of wound healing. This review explores the relationship between platelet-derived growth factor and wound healing.

  1. Factors affecting ferulic acid release from Brewer's spent grain by Fusarium oxysporum enzymatic system.

    PubMed

    Xiros, Charilaos; Moukouli, Maria; Topakas, Evangelos; Christakopoulos, Paul

    2009-12-01

    In this study, the factors affecting ferulic acid (FA) release from Brewer's spent grain (BSG), by the crude enzyme extract of Fusarium oxysporum were investigated. In order to evaluate the importance of the multienzyme preparation on FA release, the synergistic action of feruloyl esterase (FAE, FoFaeC-12213) and xylanase (Trichoderma longibrachiatum M3) monoenzymes was studied. More than double amount of FA release (1 mg g(-1) dry BSG) was observed during hydrolytic reactions by the crude enzyme extract compared to hydrolysis by the monoenzymes (0.37 mg g(-1) dry BSG). The protease content of the crude extract and the inhibitory effect of FA as an end-product were also evaluated concerning their effect on FA release. The protease treatment prior to hydrolysis by monoenzymes enhanced FA release about 100%, while, for the first time in literature, FA in solution found to have a significant inhibitory effect on FAE activity and on total FA release.

  2. Expression of vascular endothelial growth factor and basic fibroblast growth factor in extramammary Paget disease.

    PubMed

    Xu, Xiaoyun; Shao, Ning; Qiao, Di; Wang, Zengjun; Song, Ningjing; Song, Ninghong

    2015-01-01

    Extramammary Paget's disease (EMPD) is a special type of cancers. The etiology of the disease is still unclear. We aimed to study the expression differences of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in EMPD tissues and corresponding adjacent normal tissues. The mRNA expression was detected by RT-PCR and the protein expression was explored by immunohistochemistry. Higher immunostaining signal scores of bFGF and VEGF in EMPD tissues had been found (z=-3.827, P<0.001, z=-3.729, P<0.001, respectively). In addition, the mRNA expression of bFGF and VEGF was higher in EMPD tissues, which had been validated by RT-PCR (t=5.771, P<0.001, t=3.304, P=0.004, respectively). The VEGF and bFGF might be the key signaling proteins in angiogenesis of EMPD. How to block the VEGF and bFGF in EMPD and to destroy the blood supply of the tumor cells becomes the focus of our future research.

  3. Epidermal growth factor receptor mutation enhances expression of vascular endothelial growth factor in lung cancer.

    PubMed

    Hung, Ming-Szu; Chen, I-Chuan; Lin, Paul-Yann; Lung, Jr-Hau; Li, Ya-Chin; Lin, Yu-Ching; Yang, Cheng-Ta; Tsai, Ying-Huang

    2016-12-01

    Epidermal growth factor receptor (EGFR) activation has been demonstrated to have a critical role in tumor angiogenesis. In the present study, the correlation between EGFR mutations and vascular endothelial growth factor (VEGF) was investigated in lung cancer cell lines and non-small-cell lung cancer (NSCLC) tumor tissues. VEGF levels were significantly increased in culture medium of lung cancer cells and NSCLC tissues with EGFR mutations (H1650 vs. A549, P=0.0399; H1975 vs. A549, P<0.0001). Stable lung cancer cell lines expressing mutant (exon 19 deletion, E746-A750; exon 21 missense mutation, L858R) and wild-type EGFR genes were established. Significantly increased expression of VEGF and stronger inhibitory effects of gefitinib to VEGF expression were observed in exon 19 deletion stable lung cancer cells (exon 19 deletion vs. wild-type EGFR, P=0.0005). The results of the present study may provide an insight into the association of mutant EGFR and VEGF expression in lung cancer, and may assist with further development of targeted therapy for NSCLC in the future.

  4. Role of growth hormone-releasing hormone in sleep and growth impairments induced by upper airway obstruction in rats.

    PubMed

    Tarasiuk, A; Berdugo-Boura, N; Troib, A; Segev, Y

    2011-10-01

    Upper airway obstruction (UAO) can lead to abnormal growth hormone (GH) homeostasis and growth retardation but the mechanisms are unclear. We explored the effect of UAO on hypothalamic GH-releasing hormone (GHRH), which has a role in both sleep and GH regulation. The tracheae of 22-day-old rats were narrowed; UAO and sham-operated animals were sacrificed 16 days post-surgery. To stimulate slow-wave sleep (SWS) and GH secretion, rats were treated with ritanserin (5-HT(2) receptor antagonist). Sleep was measured with a telemetric system. Hypothalamic GHRH, hypothalamic GHRH receptor (GHRHR) and GH receptor, and orexin were analysed using ELISA, real-time PCR and Western blot. UAO decreased hypothalamic GHRH, GHRHR and GH receptor levels, while orexin mRNA increased (p<0.01). In UAO rats, the duration of wakefulness was elevated and the duration of SWS, paradoxical sleep and slow-wave activity was reduced (p<0.001). Ritanserin alleviated these effects, i.e. normalised hypothalamic GHRH content, decreased wake duration, increased duration and depth of SWS, and attenuated growth impairment (p<0.001). Here, we present evidence that growth retardation in UAO is associated with a reduction in hypothalamic GHRH content. Our findings show that abnormalities in the GHRH/GH axis underlie both growth retardation and SWS-disorder UAO.

  5. Extracellular matrix and growth factors in branching morphogenesis

    NASA Technical Reports Server (NTRS)

    Hardman, P.; Spooner, B. S.

    1993-01-01

    The unifying hypothesis of the NSCORT in gravitational biology postulates that the ECM and growth factors are key interrelated components of a macromolecular regulatory system. The ECM is known to be important in growth and branching morphogenesis of embryonic organs. Growth factors have been detected in the developing embryo, and often the pattern of localization is associated with areas undergoing epithelial-mesenchymal interactions. Causal relationships between these components may be of fundamental importance in control of branching morphogenesis.

  6. Cumulative release characteristics of controlled-release nitrogen and potassium fertilizers and their effects on soil fertility, and cotton growth

    PubMed Central

    Yang, Xiuyi; Geng, Jibiao; Li, Chengliang; Zhang, Min; Tian, Xiaofei

    2016-01-01

    To investigate the interacting effects of polymer coated urea (PCU) and polymer coated potassium chloride (PCPC) on cotton growth, an experiment was conducted with containerized plants in 2014 and 2015. There were two kinds of nitrogen fertilizer, PCU and urea, which were combined with PCPC at three application rates (40, 80 and 120 kg ha−1). The kinds of nitrogen fertilizer formed the main plot, while individual rates of PCPC were the subplots. The results suggested N and K release patterns for PCU and PCPC in the soil were closely matched to the N and K requirements by cotton. Soil inorganic nitrogen contents significantly increased by using PCU instead of urea, and the same trend was observed with soil available potassium contents, which also had increased rates. Meanwhile, the number of bolls and lint yields of cotton in the PCU treatments were 4.9–35.3% and 2.9–40.7% higher than from urea treatments. Lint yields also increased by 9.1–12.7% with PCPC80 and PCPC120 treatments compared with PCPC40 treatment at the same nitrogen type. Hence, application of PCU combined with 80 kg ha−1 of PCPC fertilizer on cotton increased the yields and fertilizer use efficiencies in addition to improving fiber quality and delaying leaf senescence. PMID:27966638

  7. Cumulative release characteristics of controlled-release nitrogen and potassium fertilizers and their effects on soil fertility, and cotton growth.

    PubMed

    Yang, Xiuyi; Geng, Jibiao; Li, Chengliang; Zhang, Min; Tian, Xiaofei

    2016-12-14

    To investigate the interacting effects of polymer coated urea (PCU) and polymer coated potassium chloride (PCPC) on cotton growth, an experiment was conducted with containerized plants in 2014 and 2015. There were two kinds of nitrogen fertilizer, PCU and urea, which were combined with PCPC at three application rates (40, 80 and 120 kg ha(-1)). The kinds of nitrogen fertilizer formed the main plot, while individual rates of PCPC were the subplots. The results suggested N and K release patterns for PCU and PCPC in the soil were closely matched to the N and K requirements by cotton. Soil inorganic nitrogen contents significantly increased by using PCU instead of urea, and the same trend was observed with soil available potassium contents, which also had increased rates. Meanwhile, the number of bolls and lint yields of cotton in the PCU treatments were 4.9-35.3% and 2.9-40.7% higher than from urea treatments. Lint yields also increased by 9.1-12.7% with PCPC80 and PCPC120 treatments compared with PCPC40 treatment at the same nitrogen type. Hence, application of PCU combined with 80 kg ha(-1) of PCPC fertilizer on cotton increased the yields and fertilizer use efficiencies in addition to improving fiber quality and delaying leaf senescence.

  8. Seasonal growth and mortality of juveniles of Lampsilis fasciola (Bivalvia: Unionidae) released to a fish hatchery raceway

    USGS Publications Warehouse

    Hanlon, S.D.; Neves, R.J.

    2006-01-01

    Recent efforts to restore remnant or extirpated populations of freshwater mussels have focused on artificial propagation as an effective and practical conservation strategy. Although artificially cultured juveniles have been produced and released to the wild at various times of the year, no study has investigated the best time of year to release these juveniles. Newly metamorphosed juveniles of the wavyrayed lampmussel (Lampsilis fasciola) were released into a stream-fed fish hatchery raceway during March, June, and September. Growth and survival rates were measured 32, 52, 72, and 92 days post-metamorphosis. Juveniles released in June experienced the greatest growth and survival rates. Juveniles released in September and March experienced high mortality within the first month of release and exhibited poor growth in the cool water conditions typical of those seasons. Overwinter survival exhibited a size-dependent relationship.

  9. Functional Impact of Corticotropin-Releasing Factor Exposure on Tau Phosphorylation and Axon Transport.

    PubMed

    Le, Michelle H; Weissmiller, April M; Monte, Louise; Lin, Po Han; Hexom, Tia C; Natera, Orlangie; Wu, Chengbiao; Rissman, Robert A

    2016-01-01

    Stress exposure or increased levels of corticotropin-releasing factor (CRF) induce hippocampal tau phosphorylation (tau-P) in rodent models, a process that is dependent on the type-1 CRF receptor (CRFR1). Although these preclinical studies on stress-induced tau-P provide mechanistic insight for epidemiological work that identifies stress as a risk factor for Alzheimer's disease (AD), the actual impact of stress-induced tau-P on neuronal function remains unclear. To determine the functional consequences of stress-induced tau-P, we developed a novel mouse neuronal cell culture system to explore the impact of acute (0.5hr) and chronic (2hr) CRF treatment on tau-P and integral cell processes such as axon transport. Consistent with in vivo reports, we found that chronic CRF treatment increased tau-P levels and caused globular accumulations of phosphorylated tau in dendritic and axonal processes. Furthermore, while both acute and chronic CRF treatment led to significant reduction in CREB activation and axon transport of brain-derived neurotrophic factor (BDNF), this was not the case with mitochondrial transport. Acute CRF treatment caused increased mitochondrial velocity and distance traveled in neurons, while chronic CRF treatment modestly decreased mitochondrial velocity and greatly increased distance traveled. These results suggest that transport of cellular energetics may take priority over growth factors during stress. Tau-P was required for these changes, as co-treatment of CRF with a GSK kinase inhibitor prevented CRF-induced tau-P and all axon transport changes. Collectively, our results provide mechanistic insight into the consequences of stress peptide-induced tau-P and provide an explanation for how chronic stress via CRF may lead to neuronal vulnerability in AD.

  10. Efficacy and Safety of Sustained-Release Recombinant Human Growth Hormone in Korean Adults with Growth Hormone Deficiency

    PubMed Central

    Kim, Youngsook; Hong, Jae Won; Chung, Yoon-Sok; Kim, Sung-Woon; Cho, Yong-Wook; Kim, Jin Hwa; Kim, Byung-Joon

    2014-01-01

    Purpose The administration of recombinant human growth hormone in adults with growth hormone deficiency has been known to improve metabolic impairment and quality of life. Patients, however, have to tolerate daily injections of growth hormone. The efficacy, safety, and compliance of weekly administered sustained-release recombinant human growth hormone (SR-rhGH, Declage™) supplement in patients with growth hormone deficiency were evaluated. Materials and Methods This trial is 12-week prospective, single-arm, open-label trial. Men and women aged ≥20 years with diagnosed growth hormone deficiency (caused by pituitary tumor, trauma and other pituitary diseases) were eligible for this study. Each subject was given 2 mg (6 IU) of SR-rhGH once a week, subcutaneously for 12 weeks. Efficacy and safety at baseline and within 30 days after the 12th injection were assessed and compared. Score of Assessment of Growth Hormone Deficiency in Adults (AGHDA score) for quality of life and serum IGF-1 level. Results The IGF-1 level of 108.67±74.03 ng/mL was increased to 129.01±68.37 ng/mL (p=0.0111) and the AGHDA QoL score was decreased from 9.80±6.51 to 7.55±5.76 (p<0.0001) at week 12 compared with those at baseline. Adverse events included pain, swelling, erythema, and warmth sensation at the administration site, but many adverse events gradually disappeared during the investigation. Conclusion Weekly administered SR-rhGH for 12 weeks effectively increased IGF-1 level and improved the quality of life in patients with GH deficiency without serious adverse events. PMID:24954335

  11. Nerve growth factor and epidermal growth factor stimulate clusterin gene expression in PC12 cells.

    PubMed Central

    Gutacker, C; Klock, G; Diel, P; Koch-Brandt, C

    1999-01-01

    Clusterin (apolipoprotein J) is an extracellular glycoprotein that might exert functions in development, cell death and lipid transport. Clusterin gene expression is elevated at sites of tissue remodelling, such as differentiation and apoptosis; however, the signals responsible for this regulation have not been identified. We use here the clusterin gene as a model system to examine expression in PC12 cells under the control of differentiation and proliferation signals produced by nerve growth factor (NGF) and by epidermal growth factor (EGF) respectively. NGF induced clusterin mRNA, which preceded neurite outgrowth typical of neuronal differentiation. EGF also activated the clusterin mRNA, demonstrating that both proliferation and differentiation signals regulate the gene. To localize NGF- and EGF-responsive elements we isolated the clusterin promoter and tested it in PC12 cell transfections. A 2.5 kb promoter fragment and two 1.5 and 0.3 kb deletion mutants were inducible by NGF and EGF. The contribution to this response of a conserved activator protein 1 (AP-1) motif located in the 0.3 kb fragment was analysed by mutagenesis. The mutant promoter was not inducible by NGF or EGF, which identifies the AP-1 motif as an element responding to both factors. Binding studies with PC12 nuclear extracts showed that AP-1 binds to this sequence in the clusterin promoter. These findings suggest that NGF and EGF, which give differential gene regulation in PC12 cells, resulting in neuronal differentiation and proliferation respectively, use the common Ras/extracellular signal-regulated kinase/AP-1 signalling pathway to activate clusterin expression. PMID:10215617

  12. Material factors influencing metallic whisker growth

    NASA Astrophysics Data System (ADS)

    Rodekohr, Chad L.

    Whiskering refers to the formation of slender, long, metallic filaments, much thinner than a human hair, that grow on a metallic thin film surface. They are readily observed for pure and alloyed zinc (Zn), silver (Ag), cadmium (Cd), indium (In), and tin (Sn) surfaces. The longest reported whisker length is 4.5 mm long but most high-aspect ratio whiskers range from 1-500 mum. The focus of this research is upon Sn whiskers. Sn whiskers pose serious reliability problems for the electronics industry and are known to be the source of failure in a wide range of electronic devices, such as nuclear power facilities, heart pacemakers, commercial satellites, aviation radar, telecommunication equipment, and desktop computers. The problem with whiskering has been recently exacerbated by the worldwide shift to lead (Pb) free electronics and the continuing reduction in electrical contact pitches. A thorough understanding of the growth mechanism of Sn whiskers is urgently needed. Currently, there is no universally accepted model that explains the broad range of observations on whiskering. The goals of this research are: (1) to develop a more detailed understanding of the physical mechanisms leading to the initiation and growth of Sn whiskers and (2) to outline reasonable mitigation strategies that could be followed to reduce or eliminate the problem of Sn whiskers. The major contributions of this work are: (1) A reliable method for growing Sn whiskers with predictable incubation times has been developed and tested. (2) A surface oxide is not necessary for whisker growth. (3) Intermetallic compounds (IMC) are not necessary for whisker growth. (4) Smoother, not rougher, substrate surfaces promote whisker growth. (5) Whiskers grow under both compressive and tensile thin film stress states. (6) Whisker growth increases with externally applied compression and tension forces. (7) Sn whiskers are composed of pure Sn except for the expected thin, native Sn oxide on their surface. (8) For

  13. Intraspecific genetic analysis, gamete release performance, and growth of Sargassum muticum (Fucales, Phaeophyta) from China

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Pang, Shaojun; Gao, Suqin; Shan, Tifeng

    2013-11-01

    Sargassum muticum is one of the most abundant and conspicuous native macroalgae species on the northern coasts of China. It often forms large-scale seaweed beds in subtidal zones. This investigation was designed to understand the intraspecific genetic relationships of this alga based on samples collected from four northern coastal sites of China, and to evaluate gamete release and growth capacity in laboratory conditions. The nuclear internal transcribed spacer 2 (ITS2) sequences of 16 samples from four locations were identical. Based on cox3 gene and partial rbcLS operon sequences, intraspecific genetic variability was detected with three and two ribotypes, respectively. Temperature, not irradiance, was shown to significantly affect gamete release and fertilization. Elevated temperature and irradiance enhanced the growth of germlings and vegetative branchlets. Maximum growth rate of germlings was detected at 18-24°C and an irradiance of 60-100 μmol photons/(m2·s). Under ambient conditions (12-25°C and 60-125 μmol photons/(m2·s)), relative growth rate of young branchlets could reach 7.5%/d.

  14. Heparin-binding epidermal growth factor-like growth factor and hepatocyte growth factor inhibit cholestatic liver injury in mice through different mechanisms

    PubMed Central

    Sakamoto, Kouichi; Khai, Ngin Cin; Wang, Yuqing; Irie, Rie; Takamatsu, Hideo; Matsufuji, Hiroshi; Kosai, Ken-Ichiro

    2016-01-01

    In contrast to hepatocyte growth factor (HGF), the therapeutic potential and pathophysiologic roles of heparin-binding epidermal growth factor-like growth factor (HB-EGF) in liver diseases remain relatively unknown. To address the lack of effective pharmacologic treatments for cholestatic liver injuries, as well as to clarify the biologic features of these growth factors, we explored the effects of HB-EGF and HGF in mice with cholestatic liver injury induced by bile duct ligation (BDL). The mice were assessed 3, 5 and/or 14 days after BDL (acute, subacute and/or chronic phases, respectively) and intravenous injection of adenoviral vector expressing LacZ (control), HB-EGF, HGF, or HB-EGF and HGF. HB-EGF, HGF, or a combination of the growth factors exerted potent antioncotic (antinecrotic), antiapoptotic, anticholestatic, and regenerative effects on hepatocytes in vivo, whereas no robust antiapoptotic or regenerative effects were detected in interlobular bile ducts. Based on serum transaminase levels, the acute protective effects of HB-EGF on hepatocytes were greater than those of HGF. On the other hand, liver fibrosis and cholestasis during the chronic phase were more potently inhibited by HGF compared with HB-EGF. Compared with either growth factor alone, combining HB-EGF and HGF produced greater anticholestatic and regenerative effects during the chronic phase. Taken together, these findings suggest that HB-EGF and HGF inhibited BDL-induced cholestatic liver injury, predominantly by exerting acute cytoprotective and chronic antifibrotic effects, respectively; combining the growth factors enhanced the anticholestatic effects and liver regeneration during the chronic phase. Our results contribute to a better understanding of the pathophysiologic roles of HB-EGF and HGF, as well as to the development of novel effective therapies for cholestatic liver injuries. PMID:27779646

  15. TERATOGENIC RESPONSES ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF)

    EPA Science Inventory

    TITLE:
    TERATOGENIC RESPONSES ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF). AUTHORS (ALL): Abbott, Barbara D.1; Best, Deborah S.1; Narotsky, Michael G.1. SPONSOR NAME: None INSTITUTIONS (ALL): 1. Repro Tox ...

  16. Herpesvirus-mediated systemic delivery of nerve growth factor.

    PubMed

    Wolfe, D; Goins, W F; Kaplan, T J; Capuano, S V; Fradette, J; Murphey-Corb, M; Robbins, P D; Cohen, J B; Glorioso, J C

    2001-01-01

    Sustained systemic dissemination of therapeutic proteins from peripheral sites is an attractive prospect for gene therapy applications. Replication-defective genomic herpes simplex virus type 1 (HSV-1) vectors were evaluated for their ability to express nerve growth factor (NGF) as a model gene product both locally and systemically. Intra-articular inoculation of NGF expression vectors in rabbits resulted in significant increases in joint lavage and blood plasma NGF that persisted for 1 year. A rhesus macaque injected intra-articularly displayed a comparable increase in plasma NGF for at least 6 months, at which time the serum NGF levels of this animal were sufficient to cause differentiation of PC12 cells in culture, but not to increase footpad epidermis innervation. Long-term reporter transgene expression was observed primarily in ligaments, a finding confirmed by direct inoculation of patellar ligament. Patellar ligament inoculation with a NGF vector resulted in elevated levels of circulating NGF similar to those observed following intra-articular vector delivery. These results represent the first demonstration of sustained systemic release of a transgene product using HSV vectors, raising the prospect of new applications for HSV-1 vectors in the treatment of systemic disease.

  17. Myeloid Growth Factors Promote Resistance to Mycobacterial Infection by Curtailing Granuloma Necrosis through Macrophage Replenishment.

    PubMed

    Pagán, Antonio J; Yang, Chao-Tsung; Cameron, James; Swaim, Laura E; Ellett, Felix; Lieschke, Graham J; Ramakrishnan, Lalita

    2015-07-08

    The mycobacterial ESX-1 virulence locus accelerates macrophage recruitment to the forming tuberculous granuloma. Newly recruited macrophages phagocytose previously infected apoptotic macrophages to become new bacterial growth niches. Granuloma macrophages can then necrose, releasing mycobacteria into the extracellular milieu, which potentiates their growth even further. Using zebrafish with genetic or pharmacologically induced macrophage deficiencies, we find that global macrophage deficits increase susceptibility to mycobacterial infection by accelerating granuloma necrosis. This is because reduction in the macrophage supply below a critical threshold decreases granuloma macrophage replenishment to the point where apoptotic infected macrophages, failing to get engulfed, necrose. Reducing macrophage demand by removing bacterial ESX-1 offsets the susceptibility of macrophage deficits. Conversely, increasing macrophage supply in wild-type fish by overexpressing myeloid growth factors induces resistance by curtailing necrosis. These findings may explain the susceptibility of humans with mononuclear cytopenias to mycobacterial infections and highlight the therapeutic potential of myeloid growth factors in tuberculosis.

  18. Oligosaccharides Released from Milk Glycoproteins Are Selective Growth Substrates for Infant-Associated Bifidobacteria

    PubMed Central

    Karav, Sercan; Le Parc, Annabelle; Leite Nobrega de Moura Bell, Juliana Maria; Frese, Steven A.; Kirmiz, Nina; Block, David E.; Barile, Daniela

    2016-01-01

    ABSTRACT Milk, in addition to nourishing the neonate, provides a range of complex glycans whose construction ensures a specific enrichment of key members of the gut microbiota in the nursing infant, a consortium known as the milk-oriented microbiome. Milk glycoproteins are thought to function similarly, as specific growth substrates for bifidobacteria common to the breast-fed infant gut. Recently, a cell wall-associated endo-β-N-acetylglucosaminidase (EndoBI-1) found in various infant-borne bifidobacteria was shown to remove a range of intact N-linked glycans. We hypothesized that these released oligosaccharide structures can serve as a sole source for the selective growth of bifidobacteria. We demonstrated that EndoBI-1 released N-glycans from concentrated bovine colostrum at the pilot scale. EndoBI-1-released N-glycans supported the rapid growth of Bifidobacterium longum subsp. infantis (B. infantis), a species that grows well on human milk oligosaccharides, but did not support growth of Bifidobacterium animalis subsp. lactis (B. lactis), a species which does not. Conversely, B. infantis ATCC 15697 did not grow on the deglycosylated milk protein fraction, clearly demonstrating that the glycan portion of milk glycoproteins provided the key substrate for growth. Mass spectrometry-based profiling revealed that B. infantis consumed 73% of neutral and 92% of sialylated N-glycans, while B. lactis degraded only 11% of neutral and virtually no (<1%) sialylated N-glycans. These results provide mechanistic support that N-linked glycoproteins from milk serve as selective substrates for the enrichment of infant-associated bifidobacteria capable of carrying out the initial deglycosylation. Moreover, released N-glycans were better growth substrates than the intact milk glycoproteins, suggesting that EndoBI-1 cleavage is a key initial step in consumption of glycoproteins. Finally, the variety of N-glycans released from bovine milk glycoproteins suggests that they may serve as

  19. Polymethylmethacrylate-induced release of bone-resorbing factors

    SciTech Connect

    Herman, J.H.; Sowder, W.G.; Anderson, D.; Appel, A.M.; Hopson, C.N. )

    1989-12-01

    A pseudomembranous structure that has the histological characteristics of a foreign-body-like reaction invariably develops at the bone-cement interface in the proximity of resorption of bone around aseptically loosened cemented prostheses. This study was an attempt to implicate polymethylmethacrylate in this resorptive process. Unfractionated peripheral-blood mononuclear cells (consisting of lymphocytes and monocytes) and surface-adherent cells (monocyte-enriched) were prepared from control subjects who did and did not have clinical evidence of osteoarthrosis and from patients who had osteoarthrosis and were having a revision for failure of a cemented hip or knee implant. Cells were cultured for varying periods in the presence and absence of nonpolymerized methacrylate (one to two-micrometer spherules), pulverized polymerized material, or culture chambers that were pre-coated with polymerized cement. Conditioned media that were derived from both methacrylate-stimulated cell populations were shown to contain specific bone-resorbing mediators (interleukin-1, tumor necrosis factor, or prostaglandin E2) and to directly affect bone resorption in 45Ca-labeled murine limb-bone assays.

  20. Regulation of transferrin receptor expression at the cell surface by insulin-like growth factors, epidermal growth factor and platelet-derived growth factor

    SciTech Connect

    Davis, R.J.; Kuck, L.; Faucher, M.; Czech, M.P.

    1986-05-01

    Addition of platelet-derived growth factor (PDGF), recombinant insulin-like growth factor I (rIGF-I) or epidermal growth factor (EGF) to BALB/c 3T3 fibroblasts causes a marked increase in the binding of (/sup 125/I) diferric transferrin to cell surface receptors. This effect is very rapid and is complete within 5 minutes. The effect is transient with (/sup 125/I) diferric transferrin binding returning to control values within 25 minutes. In contrast, PDGF and rIGF-I cause a prolonged stimulation of (/sup 125/I) diferric transferrin binding that could be observed up to 2 hours. The increase in the binding of (/sup 125/I) diferric transferrin caused by growth factors was investigated by analysis of the binding isotherm. EGF, PDGF and rIGF-I were found to increase the cell surface expression of transferrin receptors rather than to alter the affinity of the transferrin receptors. Furthermore, PDGF and rIGF-I stimulated the sustained uptake of (/sup 59/Fe) diferric transferrin by BALB/c 3T3 fibroblasts. Thus, the effect of these growth factors to increase the cell surface expression of the transferrin receptor appears to have an important physiological consequence.

  1. Central administration of chicken growth hormone-releasing hormone decreases food intake in chicks.

    PubMed

    Tachibana, Tetsuya; Sugimoto, Ikue; Ogino, Madoka; Khan, Md Sakirul Islam; Masuda, Keiko; Ukena, Kazuyoshi; Wang, Yajun

    2015-02-01

    Growth hormone-releasing hormone (GHRH) is well known as a stimulator of growth hormone (GH) secretion. GHRH not only stimulates GH release but also modifies feeding behavior and energy homeostasis in rodents. In chickens (Gallus gallus domesticus), on the other hand, two types of GHRH, namely, chicken GHRH (cGHRH) and cGHRH-like peptide (cGHRH-LP), have been identified. The purpose of the present study was to investigate the effect of central injection of cGHRH and cGHRH-LP on feeding behavior in chicks. Intracerebroventricular (ICV) injection of both cGHRH and cGHRH-LP (0.04 to 1 nmol) significantly decreased food intake without any abnormal behavior in chicks. Furthermore, the feeding-inhibitory effect was not abolished by co-injection of the antagonist for pituitary adenylate cyclase-activating polypeptide (PACAP) or corticotropin-releasing hormone (CRH) receptors, suggesting that the anorexigenic effect of cGHRH and cGHRH-LP might not be related to the PACAP and CRH systems in the brain of chicks. Finally, 24-h food deprivation increased mRNA expression of cGHRH but not cGHRH-LP in the diencephalon. These results suggest that central cGHRH is related to inhibiting feeding behavior and energy homeostasis in chicks.

  2. Post-release feeding and growth of hatchery-reared Japanese flounder Paralichthys olivaceus: relevance to stocking effectiveness.

    PubMed

    Tomiyama, T; Watanabe, M; Kawata, G; Ebe, K

    2011-05-01

    The feeding and growth of hatchery-reared (HR) Japanese flounder Paralichthys olivaceus of c. 100 mm total length (L(T) ) released off the coast of Fukushima, Japan, were investigated. From 2 to 15 days after release, the HR P. olivaceus frequently exhibited high empty-stomach frequency (>40%), low stomach-content mass (<1% of body mass), reduced somatic condition from release (c.-10%) and negligible growth. Thereafter, empty-stomach frequency decreased, the stomach-content mass of HR fish increased to 2-8% of body mass, the somatic condition recovered and growth rate increased to 0·5-1·5 mm day(-1) . Prey items were initially mysids, shifting thereafter to fishes such as the Japanese anchovy Engraulis japonica, as observed similarly in wild counterparts. The proportion of mysids decreased with time after release irrespective of size at release, indicating the importance of mysids for adaptation to natural food. Recapture rates at age 1 year, derived from fish market surveys, varied greatly among release years (4-11%). The variation in the recapture rates was largely accounted for by the post-release growth rates (r(2) = 0·5), suggesting a relationship between the post-release growth of HR fish and their survival and subsequent stocking effectiveness.

  3. High-growth-factor implosions (HEP4)

    SciTech Connect

    Landen, O.L.; Keane, C.J.; Hammel, B.A.

    1996-06-01

    In inertial confinement fusion (ICF), the kinetic energy of an ablating, inward-driven, solid spherical shell is used to compressionally heat the low-density fuel inside. For a given drive, the maximum achievable compressed fuel density and temperature - and hence the maximum neutron production rate depend on the degree of shell isentropy and integrity maintained during the compression. Shell integrity will be degraded by hydrodynamic instability growth of areal density imperfections in the capsule. Surface imperfections on the shell grow as a result of the Richtmyer-Meshkov and Rayleigh-Taylor (RT) instabilities when the shell is accelerated by the ablating lower-density plasma. Perturbations at the outer capsule surface are transferred hydrodynamically to the inner surface, where deceleration of the shell by the lower-density fuel gives rise to further RT growth at the pusher-fuel interface.

  4. Efficacy of glial growth factor and nerve growth factor on the recovery of traumatic facial paralysis.

    PubMed

    Yildiz, Mucahit; Karlidag, Turgut; Yalcin, Sinasi; Ozogul, Candan; Keles, Erol; Alpay, Hayrettin Cengiz; Yanilmaz, Muhammed

    2011-08-01

    The aim of this study was to assess the effects of Glial growth factor (GGF) and nerve growth factor (NGF) on nerve regeneration in facial nerve anastomosis. In this study, approximately a 1-mm segment was resected from the facial nerve and the free ends were anastomosed. All animals underwent the same surgical procedure and 30 rabbits were grouped randomly in three groups. Control group, the group without any medications; NGF group, the group receiving 250 ng/0.1 ml NGF in the epineurium at the site of anastomosis; GBF group, the group receiving 500 ng/0.1 ml GGF in the epineurium at the site of anastomosis. Medications were given at the time of surgery, and at 24 and 48 h postoperatively. After 2 months, the sites of anastomosis were excised and examined using the electron microscope. It was found that the best regeneration was in the group receiving GGF as compared to the control group in terms of nerve regeneration. Schwann cell and glial cell proliferation were found to be significantly higher in the group receiving GGF as compared to the group receiving NGF. Besides, the number of myelin debris, an indicator of degeneration, was significantly lower in the group with GGF as compared to NGF and control groups (p < 0.005). Using GGF and NGF in order to increase regeneration after nerve anastomosis in experimental traumatic facial nerve paralysis may be a hopeful alternative treatment option in the future. However, further studies on human studies are required to support these results.

  5. Psycho-Social Factors as Predictors of Success in a Work-Release Program.

    ERIC Educational Resources Information Center

    Brahen, Leonard S.; And Others

    1979-01-01

    Investigates the significance of social and environmental factors as predictors of the rehabilitative potential of an inmate. Work history must be used as a whole. The more recent a good history, the more successful an inmate's jail record. Work factors may aid in selecting narcotics-addicted inmates for work-release programs. (Author/BEF)

  6. Peptide Chain Termination: Effect of Protein S on Ribosomal Binding of Release Factors

    PubMed Central

    Goldstein, J. L.; Caskey, C. T.

    1970-01-01

    The protein factor S, previously shown to stimulate polypeptide chain termination in bacterial extracts, has two effects upon the complex formed between ribosomes, release factor, and terminator (trinucleotide) codon: (1) in the absence of GTP or GDP, S stimulates formation of an [R·UAA·ribosome] intermediate, and (2) in the presence of GTP or GDP, S participates in dissociation of this intermediate. Factor S can stimulate fMet release from [fMet-tRNAf·AUG·ribosome] intermediates in either the presence or absence of GTP or GDP. A model is proposed which relates the in vitro effects of S ± GTP (or GDP) on fMet release to the effects of S ± GTP (or GDP) on the binding and dissociation of R factor from ribosomes. PMID:5289007

  7. Dual chain synthetic heparin-binding growth factor analogs

    DOEpatents

    Zamora, Paul O.; Pena, Louis A.; Lin, Xinhua

    2009-10-06

    The invention provides synthetic heparin-binding growth factor analogs having two peptide chains each branched from a branch moiety, such as trifunctional amino acid residues, the branch moieties separated by a first linker of from 3 to about 20 backbone atoms, which peptide chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a second linker, which may be a hydrophobic second linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  8. Dual chain synthetic heparin-binding growth factor analogs

    DOEpatents

    Zamora, Paul O [Gaithersburg, MD; Pena, Louis A [Poquott, NY; Lin, Xinhua [Plainview, NY

    2012-04-24

    The invention provides synthetic heparin-binding growth factor analogs having two peptide chains each branched from a branch moiety, such as trifunctional amino acid residues, the branch moieties separated by a first linker of from 3 to about 20 backbone atoms, which peptide chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a second linker, which may be a hydrophobic second linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  9. Chimeric Aptamer-Gelatin Hydrogels as an Extracellular Matrix Mimic for Loading Cells and Growth Factors

    PubMed Central

    Zhang, Xiaolong; Battig, Mark R.; Chen, Niancao; Gaddes, Erin R.; Duncan, Katelyn L.; Wang, Yong

    2016-01-01

    It is important to synthesize materials to recapitulate critical functions of biological systems for a variety of applications such as tissue engineering and regenerative medicine. The purpose of this study was to synthesize a chimeric hydrogel as a promising extracellular matrix (ECM) mimic using gelatin, a nucleic acid aptamer and polyethylene glycol (PEG). This hydrogel had a macroporous structure that was highly permeable for fast molecular transport. Despite its high permeability, it could strongly sequester and sustainably release growth factors with high bioactivity. Notably, growth factors retained in the hydrogel could maintain ~50% bioactivity during a 14-day release test. It also provided cells with effective binding sites, which led to high efficiency of cell loading into the macroporous hydrogel matrix. When cells and growth factors were co-loaded into the chimeric hydrogel, living cells could still be observed by day 14 in a static serum-reduced culture condition. Thus, this chimeric aptamer-gelatin hydrogel constitutes a promising biomolecular ECM mimic for loading cells and growth factors. PMID:26791559

  10. Guanine is a growth factor for Legionella species.

    PubMed Central

    Pine, L; Franzus, M J; Malcolm, G B

    1986-01-01

    Evaluation of previously described chemically defined media for the growth of Legionella pneumophila showed that these media supported poor growth of several strains of L. pneumophila and did not support growth of certain of the Legionella species described later. Growth was stimulated by the dialysate from yeast extract but not by the nondialyzable fraction. Further investigations indicated that the active factors from the yeast extract dialysate were purine or pyrimidine derivatives, and certain known purines and pyrimidines were found to stimulate growth. Of these, guanine universally stimulated growth of all Legionella strains and was a growth requirement for several of the species tested. A balanced, N-(2-acetamido)-2-aminoethanesulfonic acid-buffered, chemically defined medium having guanine or a purine-pyrimidine mix is presented for the general growth of Legionella species. PMID:3700600

  11. Maternal growth factor regulation of human placental development and fetal growth.

    PubMed

    Forbes, Karen; Westwood, Melissa

    2010-10-01

    Normal development and function of the placenta is critical to achieving a successful pregnancy, as normal fetal growth depends directly on the transfer of nutrients from mother to fetus via this organ. Recently, it has become apparent from both animal and human studies that growth factors within the maternal circulation, for example the IGFs, are important regulators of placental development and function. Although these factors act via distinct receptors to exert their effects, the downstream molecules activated upon ligand/receptor interaction are common to many growth factors. The expression of numerous signaling molecules is altered in the placentas from pregnancies affected by the fetal growth complications, fetal growth restriction, and macrosomia. Thus, targeting these molecules may lead to more effective treatments for complications of pregnancy associated with altered placental development. Here, we review the maternal growth factors required for placental development and discuss their mechanism of action.

  12. Factors to predict positive results of gonadotropin releasing hormone stimulation test in girls with suspected precocious puberty.

    PubMed

    Nam, Hyo-Kyoung; Rhie, Young Jun; Son, Chang Sung; Park, Sang Hee; Lee, Kee-Hyoung

    2012-02-01

    Sometimes, the clinical findings and the results of the gonadotropin-releasing hormone (GnRH) stimulation test are inconsistent in girls with early breast development and bone age advancement. We aimed to investigate the factors predicting positive results of the GnRH stimulation test in girls with suspected central precocious puberty (CPP). We reviewed the records of 574 girls who developed breast budding before the age of 8 yr and underwent the GnRH stimulation test under the age of 9 yr. Positive results of the GnRH stimulated peak luteinizing hormone (LH) level were defined as 5 IU/L and over. Girls with the initial positive results (n = 375) showed accelerated growth, advanced bone age and higher serum basal LH, follicle-stimulating hormone, and estradiol levels, compared to those with the initial negative results (n = 199). Girls with the follow-up positive results (n = 64) showed accelerated growth and advanced bone age, compared to those with the follow-up negative results. In the binary logistic regression, the growth velocity ratio was the most significant predictive factor of positive results. We suggest that the rapid growth velocity is the most useful predictive factor for positive results in the GnRH stimulation test in girls with suspected precocious puberty.

  13. Thyrotrophin-releasing hormone induces growth hormone secretion in adult hypothyroid fowl.

    PubMed

    Harvey, S; Scanes, C G; Klandorf, H

    1988-02-01

    While thyrotrophin-releasing hormone (TRH) stimulated growth hormone (GH) secretion in adult anesthetized cockerels, the GH response was blocked in anesthetized birds pretreated with thyroxine (T4) or triiodothyronine (T3). Moreover, whereas GH secretion in conscious adult birds was poorly responsive to TRH stimulation, conscious birds made hypothyroid by goitrogen pretreatment (with propylthiouracil, methimazole, or thiourea) were responsive to TRH challenge. Basal circulating GH concentrations in the goitrogen-pretreated birds were also higher than in the vehicle-injected controls. Surgical thyroidectomy similarly increased the basal GH concentration in adult birds and promoted TRH-induced GH secretion. These results demonstrate inhibitory effects of the thyroid hormones on basal and stimulated GH secretion in adult domestic fowl and suggest that GH release in adults is partly under tonic thyroidal inhibition.

  14. Bioengineered sequential growth factor delivery stimulates brain tissue regeneration after stroke.

    PubMed

    Wang, Yuanfei; Cooke, Michael J; Sachewsky, Nadia; Morshead, Cindi M; Shoichet, Molly S

    2013-11-28

    Stroke is a leading cause of disability with no effective regenerative treatment. One promising strategy for achieving tissue repair involves the stimulation of endogenous neural stem/progenitor cells through sequential delivery of epidermal growth factor (EGF) followed by erythropoietin (EPO). Yet currently available delivery strategies such as intracerebroventricular (ICV) infusion cause significant tissue damage. We designed a novel delivery system that circumvents the blood brain barrier and directly releases growth factors to the brain. Sequential release of the two growth factors is a key in eliciting tissue repair. To control release, we encapsulate pegylated EGF (EGF-PEG) in poly(lactic-co-glycolic acid) (PLGA) nanoparticles and EPO in biphasic microparticles comprised of a PLGA core and a poly(sebacic acid) coating. EGF-PEG and EPO polymeric particles are dispersed in a hyaluronan methylcellulose (HAMC) hydrogel which spatially confines the particles and attenuates the inflammatory response of brain tissue. Our composite-mediated, sequential delivery of EGF-PEG and EPO leads to tissue repair in a mouse stroke model and minimizes damage compared to ICV infusion.

  15. A composite fibrin-based scaffold for controlled delivery of bioactive pro-angiogenetic growth factors.

    PubMed

    Briganti, Enrica; Spiller, Dario; Mirtelli, Chiara; Kull, Silvia; Counoupas, Claudio; Losi, Paola; Senesi, Sonia; Di Stefano, Rossella; Soldani, Giorgio

    2010-02-25

    The aim of this study was to fabricate and characterize in vitro a novel composite scaffold that, combining good mechanical properties with a controlled and sustained release of bioactive pro-angiogenetic growth factors, should be useful for angiogenesis induction in organs/tissues in which is also necessary to give resistance and mechanical strength. Composite scaffolds, constituted by a synthetic biocompatible material, a poly(ether)urethane-polydimethylsiloxane blend, and a biological polymer, the fibrin, were manufactured by spray, phase-inversion technique. During the manufacturing process heparin and heparin-binding growth factors, such as VEGF(165) and bFGF, were incorporated into the fibrin layer. Microscopical examinations showed a homogeneous fibrin layer firmly adherent on top of the synthetic material. Tensile tests highlighted the high elasticity of the composite scaffold and its capability to maintain integrity up to high deformation. VEGF(165) and bFGF release were controlled by fibrinogen concentration, whereas it was not affected by heparin concentration, as revealed by ELISA assay. The biological activity of the released growth factors was maintained as demonstrated by HUVEC proliferation. Finally, scaffolds induced a low monocyte mRNA expression of inflammatory markers (IL-8, L-SEL, LFA-1 and iNOS). In conclusion, the new composite scaffolds, once implanted, providing a co-localization and temporal distribution of bioactive VEGF and bFGF in addition to good mechanical properties, may be useful to stimulate new vessels formation in ischemic tissues.

  16. Sustained-release genistein from nanostructured lipid carrier suppresses human lens epithelial cell growth

    PubMed Central

    Liu, Jin-Lu; Zhang, Wen-Ji; Li, Xue-Dong; Yang, Na; Pan, Wei-San; Kong, Jun; Zhang, Jin-Song

    2016-01-01

    AIM To design and investigate the efficacy of a modified nanostructured lipid carrier loaded with genistein (Gen-NLC) to inhibit human lens epithelial cells (HLECs) proliferation. METHODS Gen-NLC was made by melt emulsification method. The morphology, particle size (PS), zeta potentials (ZP), encapsulation efficiency (EE) and in vitro release were characterized. The inhibition effect of nanostructured lipid carrier (NLC), genistein (Gen) and Gen-NLC on HLECs proliferation was evaluated by cell counting kit-8 (CCK-8) assay, gene and protein expression of the proliferation marker Ki67 were evaluated with real-time quantitative polymerase chain reaction (RT-qPCR) and immunofluorescence analyses. RESULTS The mean PS of Gen-NLC was 80.12±1.55 nm with a mean polydispersity index of 0.11±0.02. The mean ZP was -7.14±0.38 mV and the EE of Gen in the nanoparticles was 92.3%±0.73%. Transmission electron microscopy showed that Gen-NLC displayed spherical-shaped particles covered by an outer-layer structure. In vitro release experiments demonstrated a prolonged drug release for 72h. The CCK-8 assay results showed the NLC had no inhibitory effect on HLECs and Gen-NLC displayed a much more prominent inhibitory effect on cellular growth compared to Gen of the same concentration. The mRNA and protein expression of Ki67 in LECs decreased significantly in Gen-NLC group. CONCLUSION Sustained drug release by Gen-NLCs may impede HLEC growth. PMID:27275415

  17. Endothelium-Derived Hyperpolarizing Factor Mediates Bradykinin Stimulated Tissue Plasminogen Activator Release In Humans

    PubMed Central

    Rahman, Ayaz M.; Murrow, Jonathan R.; Ozkor, Muhiddin A.; Kavtaradze, Nino; Lin, Ji; De Staercke, Christine; Hooper, W. Craig; Manatunga, Amita; Hayek, Salim; Quyyumi, Arshed A.

    2014-01-01

    Aims Bradykinin stimulates tissue plasminogen activator (t-PA) release from human endothelium. Although bradykinin stimulates both nitric oxide and endothelium-derived hyperpolarizing factor (EDHF) release, the role of EDHF in t-PA release remains unexplored. This study sought to determine the mechanisms of bradykinin-stimulated t-PA release in the forearm vasculature of healthy human subjects. Methods In 33 healthy subjects (age 40.3±1.9 years) forearm blood flow (FBF) and t-PA release were measured at rest, and after intra-arterial infusions of bradykinin (400ng/min) and sodium nitroprusside (3.2 mg/min). Measurements were repeated after intra-arterial infusion of TEA (1 μmol/min), fluconazole (0.4 μmol.min-1.L-1), and NG-monomethyl-L-arginine (L-NMMA, 8 μmol/min) to block nitric oxide, and their combination in separate studies. Results Bradykinin significantly increased net t-PA release across the forearm (P<0.0001). Fluconazole attenuated both bradykinin-mediated vasodilation (-23.3±2.7% FBF, P<0.0001) and t-PA release (from 50.9±9.0 to 21.3±8.9 ng/min/100ml, P=0.02). TEA attenuated FBF (-14.7±3.2%, P=0.002) and abolished bradykinin-stimulated t-PA release (from 22.9+5.7 to - 0.8±3.6 ng/min/100ml, P=0.0002). L-NMMA attenuated FBF (P<0.0001), but did not inhibit bradykinin-induced t-PA release (P=NS). Conclusion Bradykinin-stimulated t-PA release is partly due to cytochrome P450-derived epoxides, and is inhibited by K+ca channel blockade. Thus, bradykinin stimulates both EDHF-dependent vasodilation and t-PA release. PMID:24925526

  18. Body size regulation and insulin-like growth factor signaling.

    PubMed

    Hyun, Seogang

    2013-07-01

    How animals achieve their specific body size is a fundamental, but still largely unresolved, biological question. Over the past decades, studies on the insect model system have provided some important insights into the process of body size determination and highlighted the importance of insulin/insulin-like growth factor signaling. Fat body, the Drosophila counterpart of liver and adipose tissue, senses nutrient availability and controls larval growth rate by modulating peripheral insulin signaling. Similarly, insulin-like growth factor I produced from liver and muscle promotes postnatal body growth in mammals. Organismal growth is tightly coupled with the process of sexual maturation wherein the sex steroid hormone attenuates body growth. This review summarizes some important findings from Drosophila and mammalian studies that shed light on the general mechanism of animal size determination.

  19. Cerebral hypoperfusion as a stimulus for growth hormone release in man.

    PubMed

    Kellerová, E; Vigas, M

    1980-01-01

    In healthy male volunteers the effect of a short-term cerebral ischemia due to an acute orthostatic hypotension, on the release of growth hormone (HGH) was studied. Peroral administration of guanethidine 12.5 mg t.i.d. for 3 days plus 25 mg before the experiment was used to block peripheral vascular reflexes and thus to provoke orthostatic intolerance. An extreme increase of HGH serum levels (on average from 0.8 to 13.6 ng/ml; p < 0.001) was found in subjects who developed clinical signs of syncope after assuming upright posture. The possible mechanisms of this finding are discussed.

  20. Dual control of cell growth by somatomedins and platelet-derived growth factor.

    PubMed Central

    Stiles, C D; Capone, G T; Scher, C D; Antoniades, H N; Van Wyk, J J; Pledger, W J

    1979-01-01

    Quiescent BALB/c 3T3 cells exposed briefly to a platelet-derived growth factor (PDGF) become "competent" to replicate their DNA but do not "progress" into S phase unless incubated with growth factors contained in platelet-poor plasma. Plasma from hypophysectomized rats is deficient in progression activity; it does not stimulate PDGF-treated competent cells to synthesize DNA, demonstrating that somatomedin C is required for progression. Various growth factors were tested for progression activity and competence activity by using BALB/c 3T3 tissue culture assays. Multiplication stimulating activity and other members of the somatomedin family of growth factors are (like somatomedin C) potent mediators of progression. Other mitogenic agents, such as fibroblast growth factor, are (like PDGF) potent inducers of competence. Growth factors with potent progression activity have little or no competence activity and vice versa. In contrast, simian virus 40 provides both competence and progression activity. Coordinate control of BALB/c 3T3 cell growth in vitro by competence factors and somatomedins may be a specific example of a common pattern of growth regulation in animal tissues. PMID:312500

  1. Cardiac Regeneration using Growth Factors: Advances and Challenges

    PubMed Central

    Rebouças, Juliana de Souza; Santos-Magalhães, Nereide Stela; Formiga, Fabio Rocha

    2016-01-01

    Myocardial infarction is the most significant manifestation of ischemic heart disease and is associated with high morbidity and mortality. Novel strategies targeting at regenerating the injured myocardium have been investigated, including gene therapy, cell therapy, and the use of growth factors. Growth factor therapy has aroused interest in cardiovascular medicine because of the regeneration mechanisms induced by these biomolecules, including angiogenesis, extracellular matrix remodeling, cardiomyocyte proliferation, stem-cell recruitment, and others. Together, these mechanisms promote myocardial repair and improvement of the cardiac function. This review aims to address the strategic role of growth factor therapy in cardiac regeneration, considering its innovative and multifactorial character in myocardial repair after ischemic injury. Different issues will be discussed, with emphasis on the regeneration mechanisms as a potential therapeutic resource mediated by growth factors, and the challenges to make these proteins therapeutically viable in the field of cardiology and regenerative medicine. PMID:27355588

  2. Novel polymeric scaffolds using protein microbubbles as porogen and growth factor carriers.

    PubMed

    Nair, Ashwin; Thevenot, Paul; Dey, Jagannath; Shen, Jinhui; Sun, Man-Wu; Yang, Jian; Tang, Liping

    2010-02-01

    Polymeric tissue engineering scaffolds prepared by conventional techniques like salt leaching and phase separation are greatly limited by their poor biomolecule-delivery abilities. Conventional methods of incorporation of various growth factors, proteins, and/or peptides on or in scaffold materials via different crosslinking and conjugation techniques are often tedious and may affect scaffold's physical, chemical, and mechanical properties. To overcome such deficiencies, a novel two-step porous scaffold fabrication procedure has been created in which bovine serum albumin microbubbles (henceforth MB) were used as porogen and growth factor carriers. Polymer solution mixed with MB was phase separated and then lyophilized to create porous scaffold. MB scaffold triggered substantially lesser inflammatory responses than salt-leached and conventional phase-separated scaffolds in vivo. Most importantly, the same technique was used to produce insulin-like growth factor-1 (IGF-1)-eluting porous scaffolds, simply by incorporating IGF-1-loaded MB (MB-IGF-1) with polymer solution before phase separation. In vitro such MB-IGF-1 scaffolds were able to promote cell growth to a much greater extent than scaffold soaked in IGF-1, confirming the bioactivity of the released IGF-1. Further, such MB-IGF-1 scaffolds elicited IGF-1-specific collagen production in the surrounding tissue in vivo. This novel growth factor-eluting scaffold fabrication procedure can be used to deliver a range of single or combination of bioactive biomolecules to substantially promote cell growth and function in degradable scaffold.

  3. Polyamines: essential factors for growth and survival.

    PubMed

    Kusano, T; Berberich, T; Tateda, C; Takahashi, Y

    2008-08-01

    Polyamines are low molecular weight, aliphatic polycations found in the cells of all living organisms. Due to their positive charges, polyamines bind to macromolecules such as DNA, RNA, and proteins. They are involved in diverse processes, including regulation of gene expression, translation, cell proliferation, modulation of cell signalling, and membrane stabilization. They also modulate the activities of certain sets of ion channels. Because of these multifaceted functions, the homeostasis of polyamines is crucial and is ensured through regulation of biosynthesis, catabolism, and transport. Through isolation of the genes involved in plant polyamine biosynthesis and loss-of-function experiments on the corresponding genes, their essentiality for growth is reconfirmed. Polyamines are also involved in stress responses and diseases in plants, indicating their importance for plant survival. This review summarizes the recent advances in polyamine research in the field of plant science compared with the knowledge obtained in microorganisms and animal systems.

  4. Actions of activin A, connective tissue growth factor, hepatocyte growth factor and teratocarcinoma-derived growth factor 1 on the development of the bovine preimplantation embryo.

    PubMed

    Kannampuzha-Francis, Jasmine; Tribulo, Paula; Hansen, Peter J

    2016-05-17

    The reproductive tract secretes bioactive molecules collectively known as embryokines that can regulate embryonic growth and development. In the present study we tested four growth factors expressed in the endometrium for their ability to modify the development of the bovine embryo to the blastocyst stage and alter the expression of genes found to be upregulated (bone morphogenetic protein 15 (BMP15) and keratin 8, type II (KRT8)) or downregulated (NADH dehydrogenase 1 (ND1) and S100 calcium binding protein A10 (S100A10)) in embryos competent to develop to term. Zygotes were treated at Day 5 with 0.01, 0.1 or 1.0 nM growth factor. The highest concentration of activin A increased the percentage of putative zygotes that developed to the blastocyst stage. Connective tissue growth factor (CTGF) increased the number of cells in the inner cell mass (ICM), decreased the trophectoderm : ICM ratio and increased blastocyst expression of KRT8 and ND1. The lowest concentration of hepatocyte growth factor (HGF) reduced the percentage of putative zygotes becoming blastocysts. Teratocarcinoma-derived growth factor 1 increased total cell number at 0.01 nM and expression of S100A10 at 1.0 nM, but otherwise had no effects. Results confirm the prodevelopmental actions of activin A and indicate that CTGF may also function as an embryokine by regulating the number of ICM cells in the blastocyst and altering gene expression. Low concentrations of HGF were inhibitory to development.

  5. A growth factor phenotype map for ovine preimplantation development.

    PubMed

    Watson, A J; Watson, P H; Arcellana-Panlilio, M; Warnes, D; Walker, S K; Schultz, G A; Armstrong, D T; Seamark, R F

    1994-04-01

    The reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the patterns of expression for several growth factor ligand and receptor genes during ovine preimplantation development. Transcripts for insulin-like growth factor (IGF)-I, IGF-II, and the receptors for insulin and IGF-I were detected throughout ovine preimplantation development from the 1-cell to the blastocyst stage. Transforming growth factor alpha (TGF alpha) transcripts were also detected throughout ovine preimplantation development. The mRNAs encoding basic fibroblast growth factor (bFGF) were detected in all stages of the ovine preimplantation embryo, although the relative abundance of this transcript consistently decreased from the 1-cell to the blastocyst stage, suggesting that it may represent a maternal transcript in early sheep embryos. Transcripts encoding ovine trophoblast protein (oTP) were detected only within blastocyst-stage embryos. Primary ovine oviduct cell cultures express the transcripts for IGF-II, IGF-I, TGF alpha, bFGF, TGF beta 1, and the receptors for insulin and IGF-I, suggesting that paracrine growth factor circuits may exist between the oviduct epithelium and the early ovine embryo. Transcripts for insulin, epidermal growth factor (EGF), and nerve growth factor (NGF) were not detected in any stage of the ovine preimplantation embryo or within the oviduct cell preparations. The expression of growth factor transcripts very early in mammalian development would predict that these molecules fulfil a necessary role(s) in supporting the progression of early embryos through the preimplantation interval. Our future efforts will be directed to understanding the nature of these putative regulatory pathways.

  6. Factors Affecting Release of Heat-Labile Enterotoxin by Enterotoxigenic Escherichia coli

    PubMed Central

    Kunkel, Steven L.; Robertson, Donald C.

    1979-01-01

    Various conditions affecting the release of heat-labile enterotoxin (LT) by enterotoxigenic Escherichia coli have been examined. The pH of a defined medium containing three amino acids, M-9 salts, and 0.5% glucose decreased to less than 7.0 in early log phase of growth, and no extracellular LT was detected. Adjustment of the pH at 8 h from 6.0 to 8.0 resulted in a concomitant increase in LT activity in culture supernatants. The release of cell-associated LT was significantly reduced by preincubation with protease inhibitors and increased by preincubation with trypsin. Cell-associated LT was not released by pH adjustment of cells grown at 21°C; however, polymyxin B treatment released a toxin species active in only the pigeon erythrocyte lysate (PEL) assay system. As the growth temperature was increased, polymyxin B released toxin species which exhibited both PEL and Y-1 adrenal tumor cell activity. Polymyxin B extracts of enterotoxigenic E. coli in early log phase grown at 37°C possessed only PEL activity, whereas extracts from cells in late-log and stationary phases had biological activity in both assay systems. Also, LT released by pH adjustment from mid-log to stationary phase was active in both PEL and Y-1 adrenal tumor cell assays. Gel electrophoresis of polymyxin B extracts revealed at least three molecular weight species active in either the PEL (22,000 daltons and 30,000 daltons) or both the PEL and the Y-1 adrenal tumor cell assay (72,000 daltons), depending on the growth temperature. These observations may help to explain the chemical and biological heterogeneity of most LT preparations and facilitate purification of LT by increasing the yield of enterotoxin. PMID:37162

  7. Effect of sericin on diabetic hippocampal growth hormone/insulin-like growth factor 1 axis

    PubMed Central

    Chen, Zhihong; Yang, Songhe; He, Yaqiang; Song, Chengjun; Liu, Yongping

    2013-01-01

    Previous studies have shown that sericin extracted from silk cocoon significantly reduces blood glucose levels and protects the nervous system against diabetes mellitus. In this study, a rat type 2 diabetes mellitus model was established by intraperitoneal injection of 25 mg/kg streptozotocin for 3 successive days, following which the rats were treated with sericin for 35 days. After treatment, the blood glucose levels of the diabetic rats decreased significantly, the growth hormone level in serum and its expression in the hippocampus decreased significantly, while the insulin-like growth factor-1 level in serum and insulin-like growth factor-1 and growth hormone receptor expression in the hippocampus increased significantly. The experimental findings indicate that sericin improves disorders of the growth hormone/insulin-like growth factor 1 axis to alleviate hippocampal damage in diabetic rats. PMID:25206472

  8. Mediation of wound-related Rous sarcoma virus tumorigenesis by TFG (transforming growth factor)-. beta

    SciTech Connect

    Sieweke, M.H.; Bissell, M.J. ); Thompson, N.L.; Sporn, M.B. )

    1990-06-29

    In Rous sarcoma virus (RSV)-infected chickens, wounding leads to tumor formation with nearly 100% frequency in tissues that would otherwise remain tumor-free. Identifying molecular mediators of this phenomenon should yield important clues to the mechanisms involved in RSV tumorigenesis. Immunohistochemical staining showed that TGF-{beta} is present locally shortly after wounding, but not in unwounded controls. In addition, subcutaneous administration of recombinant transforming growth factor {beta}1 (TGF-{beta}1) could substitute completely for wounding in tumor induction. A treatment protocol of four doses of 800 nanograms of TGF-{beta} resulted in v-src-expressing tumors with 100% frequency; four doses of only 10 nanograms still led to tumor formation in 80% of the animals. This effect was specific, as other growth factors with suggested roles in would healing did not elicit the same response. Epidermal growth factor (EGF) or TGF-{alpha} had no effect, and platelet-derived growth factor (PDGF) or insulin-like growth factor-1 (IGF-1) yielded only occasional tumors after longer latency. TGF-{beta} release during the would-healing response may thus be a critical event that creates a conducive environment for RSV tumorigenesis and may act as a cofactor for transformation in this system. 31 refs., 3 figs., 2 tabs.

  9. Lifetime growth in wild meerkats: incorporating life history and environmental factors into a standard growth model.

    PubMed

    English, Sinéad; Bateman, Andrew W; Clutton-Brock, Tim H

    2012-05-01

    Lifetime records of changes in individual size or mass in wild animals are scarce and, as such, few studies have attempted to model variation in these traits across the lifespan or to assess the factors that affect them. However, quantifying lifetime growth is essential for understanding trade-offs between growth and other life history parameters, such as reproductive performance or survival. Here, we used model selection based on information theory to measure changes in body mass over the lifespan of wild meerkats, and compared the relative fits of several standard growth models (monomolecular, von Bertalanffy, Gompertz, logistic and Richards). We found that meerkats exhibit monomolecular growth, with the best model incorporating separate growth rates before and after nutritional independence, as well as effects of season and total rainfall in the previous nine months. Our study demonstrates how simple growth curves may be improved by considering life history and environmental factors, which may be particularly relevant when quantifying growth patterns in wild populations.

  10. The neglected role of insulin-like growth factors in the maternal circulation regulating fetal growth.

    PubMed

    Sferruzzi-Perri, A N; Owens, J A; Pringle, K G; Roberts, C T

    2011-01-01

    Maternal insulin-like growth factors (IGFs) play a pivotal role in modulating fetal growth via their actions on both the mother and the placenta. Circulating IGFs influence maternal tissue growth and metabolism, thereby regulating nutrient availability for the growth of the conceptus. Maternal IGFs also regulate placental morphogenesis, substrate transport and hormone secretion, all of which influence fetal growth either via indirect effects on maternal substrate availability, or through direct effects on the placenta and its capacity to supply nutrients to the fetus. The extent to which IGFs influence the mother and/or placenta are dependent on the species and maternal factors, including age and nutrition. As altered fetal growth is associated with increased perinatal morbidity and mortality and a greater risk of developing degenerative diseases in adult life, understanding the role of maternal IGFs during pregnancy is essential in order to identify mechanisms underlying altered fetal growth and offspring programming.

  11. Growth hormone releasing hormone (GHRH) signaling modulates intermittent hypoxia-induced oxidative stress and cognitive deficits in mouse.

    PubMed

    Nair, Deepti; Ramesh, Vijay; Li, Richard C; Schally, Andrew V; Gozal, David

    2013-11-01

    Intermittent hypoxia (IH) during sleep, such as occurs in obstructive sleep apnea (OSA), leads to degenerative changes in the hippocampus, and is associated with spatial learning deficits in adult mice. In both patients and murine models of OSA, the disease is associated with suppression of growth hormone (GH) secretion, which is actively involved in the growth, development, and function of the central nervous system (CNS). Recent work showed that exogenous GH therapy attenuated neurocognitive deficits elicited by IH during sleep in rats. Here, we show that administration of the Growth Hormone Releasing Hormone (GHRH) agonist JI-34 attenuates IH-induced neurocognitive deficits, anxiety, and depression in mice along with reduction in oxidative stress markers such as MDA and 8-hydroxydeoxyguanosine, and increases in hypoxia inducible factor-1α DNA binding and up-regulation of insulin growth factor-1 and erythropoietin expression. In contrast, treatment with a GHRH antagonist (MIA-602) during intermittent hypoxia did not affect any of the IH-induced deleterious effects in mice. Thus, exogenous GHRH administered as the formulation of a GHRH agonist may provide a viable therapeutic intervention to protect IH-vulnerable brain regions from OSA-associated neurocognitive dysfunction. Sleep apnea, characterized by chronic intermittent hypoxia (IH), is associated with substantial cognitive and behavioral deficits. Here, we show that administration of a GHRH agonist (JI-34) reduces oxidative stress, increases both HIF-1α nuclear binding and downstream expression of IGF1 and erythropoietin (EPO) in hippocampus and cortex, and markedly attenuates water maze performance deficits in mice exposed to intermittent hypoxia during sleep.

  12. Neutrophil biology and the next generation of myeloid growth factors.

    PubMed

    Dale, David C

    2009-01-01

    Neutrophils are the body's critical phagocytic cells for defense against bacterial and fungal infections; bone marrow must produce approximately 10 x 10(9) neutrophils/kg/d to maintain normal blood neutrophil counts. Production of neutrophils depends on myeloid growth factors, particularly granulocyte colony-stimulating factor (G-CSF). After the original phase of development, researchers modified these growth factors to increase their size and delay renal clearance, increase their biologic potency, and create unique molecules for business purposes. Pegylated G-CSF is a successful product of these efforts. Researchers have also tried to identify small molecules to serve as oral agents that mimic the parent molecules, but these programs have been less successful. In 2006, the European Medicines Agency established guidelines for the introduction of new biologic medicinal products claimed to be similar to reference products that had previously been granted marketing authorization in the European community, called bio-similars. Globally, new and copied versions of G-CSF and other myeloid growth factors are now appearing. Some properties of the myeloid growth factors are similar to other agents, offering opportunities for the development of alternative drugs and treatments. For example, recent research shows that hematopoietic progenitor cells can be mobilized with a chemokine receptor antagonist, chemotherapy, G-CSF, and granulocyte macrophage colony-stimulating factor. Advances in neutrophil biology coupled with better understanding and development of myeloid growth factors offer great promise for improving the care of patients with cancer and many other disorders.

  13. Transforming growth factor β signaling in uterine development and function.

    PubMed

    Li, Qinglei

    2014-01-01

    Transforming growth factor β (TGFβ) superfamily is evolutionarily conserved and plays fundamental roles in cell growth and differentiation. Mounting evidence supports its important role in female reproduction and development. TGFBs1-3 are founding members of this growth factor family, however, the in vivo function of TGFβ signaling in the uterus remains poorly defined. By drawing on mouse and human studies as a main source, this review focuses on the recent progress on understanding TGFβ signaling in the uterus. The review also considers the involvement of dysregulated TGFβ signaling in pathological conditions that cause pregnancy loss and fertility problems in women.

  14. Differential sensitivity of growth hormone-releasing hormone and somatostatin release from perifused mouse hypothalamic fragments in response to glucose deficiency.

    PubMed

    Sato, M; Frohman, L A

    1993-06-01

    The effects of glucose deficiency on growth hormone (GH)-releasing hormone (GRH) and somatostatin (SRIH) release from mouse hypothalamic fragments were investigated using an in vitro perifusion system. Fragments were perifused with Krebs-Ringer bicarbonate solution (KRB) containing 5.6 mM glucose for 3 h followed by reduced glucose concentrations in KRB for the next 2 h. GRH release was simulated by 0.7-2.8 mM glucose in an inverse concentration-dependent manner. In contrast, SRIH release was not stimulated by glucose at concentrations of 2.8 and 1.4 mM; only at 0.7 mM was there a modest stimulation of SRIH release that was comparable to the effect of 2.8 mM glucose on GRH release. The maximal stimulation of GRH and SRIH release by 0.7 mM glucose was 221 and 150%, respectively, of controls. Glucose concentrations of 11.2 and 22.4 mM inhibited GRH release but did not alter SRIH release. The glucose analog 2-deoxy-D-glucose (2-DG; 5.6-39.2 mM) also stimulated GRH release in a dose-dependent manner, and SRIH release was less sensitive to 2-DG than was GRH. The maximal stimulation of GRH and SRIH release by 39.2 mM 2-DG was 190 and 147%, respectively, of controls. Increases in GRH and SRIH release stimulated by 30 mM KCl 1 h after exposure to low glucose or 2-DG were not significantly different from those after exposure to 5.6 mM glucose. However, the SRIH response to K(+)-induced depolarization was much greater than that of GRH. The glucose intermediate pyruvate (4.9 and 9.8 mM) partially inhibited both GRH and SRIH release induced by 0.7 mM glucose.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. [Novel role of growth factors in ovary function].

    PubMed

    Amsterdam, Abraham

    2010-12-01

    The development of the DNA microarray technique facilitated systematic studies of the modulation of gene function. Considerable attention has been focused on members of the growth factor family to elucidate the main regulators of oocyte maturation and ovarian follicle rupture. Among these growth factors, it was found, both in rodents and in humans, that amphiregulin (Ar) and epiregulin (Ep) of the epidermal growth factor (EGF) family were dramatically up-regulated by gonadotrophins in the intact ovary and in primary granulosa cells, respectively. Their role in cumulus expansion and oocyte maturation was established in rodents, and their synthesis under LH stimulation in granulosa cells was demonstrated in humans. To be activated, Ar and Ep must be cleaved by a disintegrin and metalloproteinases (ADAMs) family. However, the precise processing of Ar and Ep by the cumulus cells is still obscure. Future investigations using DNA microarray technique may reveal the repertoire of genes activated in Ar- and Ep-stimulated cumulus cells and may help elucidate the molecular basis of ovulation. EFG-like factors are also involved in triggering ovarian cancer The author hypothesized that the normal ovary maintains cyclicity in the formation of these growth factors preventing the ovary from developing ovarian cancer In ovarian cancer these growth factors are continuously formed in an autocrine manner, leading to transformation and subsequently to ovarian cancer. These growth factors are essential for both normal and neoplastic transformation of the ovary. Taking into consideration these growth factors in the treatment of ovarian malfunction may be one way of curing ovarian cancer.

  16. Effective Delivery of Doxycycline and Epidermal Growth Factor for Expedited Healing of Chronic Wounds

    NASA Astrophysics Data System (ADS)

    Kulkarni, Abhilash

    The problems and high medical costs associated with chronic wounds necessitate an economical bioactive wound dressing. A new strategy was investigated to inhibit MMP-9 proteases and to release epidermal growth factor (EGF) to enhance healing. Doxycycline (DOX) and EGF were encapsulated on polyacrylic acid modified polyurethane film (PAA-PU) using Layer-by-Layer (LbL) assembly. The number of bilayers tuned the concentration of DOX and EGF released over time with over 94% bioactivity of EGF retained over 4 days. A simple wound model in which MMP-9 proteases were added to cell culture containing fibroblast cells demonstrated that DOX inhibited the proteases providing a protective environment for the released EGF to stimulate cell migration and proliferation at a faster healing rate. In the presence of DOX, only small amounts of the highly bioactive EGF are sufficient to close the wound. Results show that this is new and promising bioactive dressing for effective wound management.

  17. Recycling of epidermal growth factor in a human pancreatic carcinoma cell line

    SciTech Connect

    Korc, M.; Magun, B.E.

    1985-09-01

    PANC-1 human pancreatic carcinoma cells readily bound and internalized /sup 125/I-labeled epidermal growth factor (EGF). Bound /sup 125/I-labeled EGF was then partially processed to a number of high molecular weight acidic species. Percoll gradient centrifugation of cell homogenates indicated that the majority of /sup 125/I activity localized to several intracellular vesicular compartments. Both intact EGF and its processed species were subsequently released into the incubation medium. A major portion of the released radioactivity was capable of rebinding to the cell. Only a small amount of bound /sup 125/I-labeled EGF was degraded to low molecular weight products, and this degradation was completely blocked by methylamine. These findings suggest that in PANC-1 cells, bound EGF undergoes only limited processing. Both intact EGF and its major processed species bypass the cellular degradative pathways, are slowly released from the cell, and then rebind to the cell.

  18. Testosterone inhibition of growth hormone release stimulated by a growth hormone secretagogue: studies in the rat and dog.

    PubMed

    Rigamonti, Antonello E; Cella, Silvano G; Giordani, Claudio; Bonomo, Sara M; Giunta, Marialuisa; Sartorio, Alessandro; Muller, Eugenio

    2006-01-01

    Anabolic steroids are frequently taken by athletes and bodybuilders together with recombinant human GH (rhGH), though there is some scientific evidence that the use of anabolic steroids reverses the rhGH-induced effects. Recently, we have shown that treatment with rhGH (0.2 IU/kg s.c., daily x 12 days) in the dog markedly reduced the canine GH (cGH) responses stimulated by EP51216, a GH secretagogue (GHS), evaluated after 3 and 5 daily rhGH injections, and that the inhibition was still present a few days after rhGH discontinuation. The aim of the present study was to evaluate in the dog the GH response to EP51216 (125 mug/kg i.v.) in a condition of enhanced androgenic function (i.e. acute injection or 15-day treatment with testosterone at the dose of 2 mg/kg i.m. on alternate days), and in the hypophysectomized rat the hypothalamic and hippocampal expression of ghrelin, the receptor of GHSs (GHS-R), GH-releasing hormone (GHRH) and somatostatin (SS) after specific hormonal replacement therapies (testosterone, 1 mg/kg/day s.c.; hydrocortisone, 500 mug/kg/day s.c.; rhGH, 400 mug/kg/day s.c.; 0.9% saline 0.1 ml/kg/day s.c.; x11 days). In the dog experiments, under baseline conditions, a single injection of EP51216 elicited an abrupt rise of plasma cGH. Twenty-four hours from the acute bolus injection of testosterone, C(max) and AUC(0-90) of the GHS-stimulated cGH response were significantly lower than baseline cGH response; 5 days later, there was still a significant decrease of either parameter versus the original values. Short-term treatment with testosterone markedly reduced the GHS-stimulated cGH responses evaluated during (5th bolus) and at the end (8th bolus) of testosterone treatment. Four and 8 days after testosterone withdrawal, the EP51216-stimulated cGH response was still significantly reduced when compared with that under baseline conditions. Plasma concentrations of insulin-like growth factor 1 (IGF-1) were stable until the 5th bolus of testosterone and

  19. Intrauterine growth correlation to postnatal growth--influence of risk factors and complications in pregnancy.

    PubMed

    Larsen, T; Greisen, G; Petersen, S

    1997-01-20

    In a population of 616 pregnant women with increased risk of intrauterine growth retardation, we examined the relationship of third trimester fetal growth to maternal and pregnancy risk factors, the infants condition at birth, and postnatal growth. Intrauterine growth velocity was calculated from repeated estimations of fetal weight using ultrasound. Postnatal growth up to 3 months was measured in 313 of the infants. Intrauterine growth velocity was directly correlated to birth weight deviation (R = 0.35, P < 0.0001) and inversely correlated to postnatal growth (R = 0.21, P = 0.0001). Heavy smoking throughout pregnancy was the most pronounced factor associated with loss of fetal growth percentiles (P = 0.006), and it was also associated with postnatal catchup (P = 0.01). Infants who needed neonatal care had significantly lower intrauterine growth velocities compared to the rest of the study group; no correlation was found between intrauterine growth velocity and Apgar scores or umbilical pH. It is concluded that growth retardation in the third trimester can be identified by ultrasound fetometry, and is associated with maladaptation at birth and postnatal catchup. However, the correlations were weak suggesting that deviation at birth reflects, only to a limited degree, acceleration or deceleration of growth in the third trimester.

  20. Fibroblast growth factor receptor levels decrease during chick embryogenesis

    PubMed Central

    1990-01-01

    Two putative receptors for fibroblast growth factor (FGF) of approximately 150 and 200 kD were identified in membrane preparations from chick embryos. Specific binding (femtomoles/milligram) of 125I- aFGF to whole chick embryonic membranes was relatively constant from day 2 to 7, then decreased fivefold between days 7 and 13. Day-19 chick embryos retained 125I-aFGF binding at low levels to brain, eye, and liver tissues but not to skeletal muscle or cardiac tissues. The 200-kD FGF receptor began to decline between day 4.5 and 7 and was barely detectable by day 9, whereas the 150-kD FGF receptor began to decline by day 7 but was still detectable in day-9 embryonic membranes. It is not known whether the two FGF-binding proteins represent altered forms of one polypeptide, but it is clear that their levels undergo differential changes during development. Because endogenous chick FGF may remain bound to FGF receptor in membrane preparations, membranes were treated with acidic (pH 4.0) buffers to release bound FGF; such treatment did not affect 125I-aFGF binding and moderately increased the number of binding sites in day-7 and -19 embryos. Consequently, the observed loss of high affinity 125I-aFGF binding sites and FGF-binding polypeptides most likely represents a loss of FGF receptor protein. These experiments provide in vivo evidence to support the hypothesis that regulation of FGF receptor levels may function as a mechanism for controlling FGF-dependent processes during embryonic development. PMID:2153684

  1. Growth hormone-releasing hormone (GHRH) antagonists inhibit the proliferation of androgen-dependent and -independent prostate cancers

    PubMed Central

    Letsch, Markus; Schally, Andrew V.; Busto, Rebeca; Bajo, Ana M.; Varga, Jozsef L.

    2003-01-01

    The antiproliferative effects of an antagonist of growth hormone-releasing hormone (GHRH) JV-1-38 were evaluated in nude mice bearing s.c. xenografts of LNCaP and MDA-PCa-2b human androgen-sensitive and DU-145 androgen-independent prostate cancers. In the androgen-sensitive models, JV-1-38 greatly potentiated the antitumor effect of androgen deprivation induced by surgical castration, but was ineffective when given alone. Thus, in castrated animals bearing MDA-PCa-2b cancers, the administration of JV-1-38 for 35 days virtually arrested tumor growth (94% inhibition vs. intact control, P < 0.01; and 75% vs. castrated control, P < 0.05). The growth of LNCaP tumors was also powerfully suppressed by JV-1-38 combined with castration (83% inhibition vs. intact control, P < 0.01; and 68% vs. castrated control, P < 0.05). However, in androgen-independent DU-145 cancers, JV-1-38 alone could inhibit tumor growth by 57% (P < 0.05) after 45 days. In animals bearing MDA-PCa-2b and LNCaP tumors, the reduction in serum prostate-specific antigen levels, after therapy with JV-1-38, paralleled the decrease in tumor volume. Inhibition of MDA-PCa-2b and DU-145 cancers was associated with the reduction in the expression of mRNA and protein levels of vascular endothelial growth factor. The mRNA expression for GHRH receptor splice variants was found in all these models of prostate cancer. Our results demonstrate that GHRH antagonists inhibit androgen-independent prostate cancers and, after combination with androgen deprivation, also androgen-sensitive tumors. Thus, the therapy with GHRH antagonist could be considered for the management of both androgen-dependent or -independent prostate cancers. PMID:12538852

  2. Modulation of colony stimulating factor release and apoptosis in human colon cancer cells by anticancer drugs

    PubMed Central

    Calatayud, S; Warner, T D; Mitchell, J A

    2002-01-01

    Modulation of the immune response against tumour cells is emerging as a valuable approach for cancer treatment. Some experimental studies have shown that secretion of colony stimulating factors by cancer cells reduces their tumorigenicity and increases their immunogenicity probably by promoting the cytolitic and antigen presenting activities of leukocytes. We have observed that human colon cancer cells (HT-29) are able to secrete granulocyte-macrophage-colony stimulating factor, granulocyte-colony stimulating factor and macrophage-colony stimulating factor when stimulated with cytokines (IL-1β and TNF-α). In this study we assessed, for the first time, the effects of several anticancer drugs on colony stimulating factor release or apoptosis in HT-29 cells. Cytokine-induced release of granulocyte-macrophage-colony stimulating factor, granulocyte-colony stimulating factor and macrophage-colony stimulating factor was significantly increased by cisplatin and 6-mercaptopurine. Taxol only increased macrophage-colony stimulating factor release while reduced that of granulocyte-colony stimulating factor. No changes in colony stimulating factor secretion were observed after treatment with methotrexate. Only cisplatin and taxol induced apoptosis in these cells. Secretion of colony stimulating factors by colon cancer cells may contribute to the immune host response against them. Anticancer drugs such as cisplatin and 6-mercaptopurine increase colony stimulating factor secretion by cytokine stimulated cancer cells probably through mechanisms different to those leading to cell apoptosis, an effect that may contribute to their anti-neoplasic action. British Journal of Cancer (2002) 86, 1316–1321. DOI: 10.1038/sj/bjc/6600240 www.bjcancer.com © 2002 Cancer Research UK PMID:11953891

  3. [Enhancement of epidermal regeneration by recombinant vaccinia virus growth factor].

    PubMed

    Petrov, V S; Cheshenko, I O; Omigov, V V; Azaev, M Sh; Krendel'shchikov, A V; Ovechkina, L G; Cheshenko, N V; Malygin, E G

    1998-01-01

    Examining the specific activity has showed that recombinant vaccinia virus growth factor binds to appropriate receptors on the A-431 cell surface and prompts the healing acceleration of degree III burns in rats. This recombinant factor did not demonstrate pyrogenicity or toxicogenicity in tests on rabbits, guinea-pits, noninbred albino mice.

  4. Novel Polymeric Scaffolds Using Protein Microbubbles as Porogen and Growth Factor Carriers

    PubMed Central

    Nair, Ashwin; Thevenot, Paul; Dey, Jagannath; Shen, Jinhui; Sun, Man-Wu; Yang, Jian

    2010-01-01

    Polymeric tissue engineering scaffolds prepared by conventional techniques like salt leaching and phase separation are greatly limited by their poor biomolecule-delivery abilities. Conventional methods of incorporation of various growth factors, proteins, and/or peptides on or in scaffold materials via different crosslinking and conjugation techniques are often tedious and may affect scaffold's physical, chemical, and mechanical properties. To overcome such deficiencies, a novel two-step porous scaffold fabrication procedure has been created in which bovine serum albumin microbubbles (henceforth MB) were used as porogen and growth factor carriers. Polymer solution mixed with MB was phase separated and then lyophilized to create porous scaffold. MB scaffold triggered substantially lesser inflammatory responses than salt-leached and conventional phase-separated scaffolds in vivo. Most importantly, the same technique was used to produce insulin-like growth factor-1 (IGF-1)–eluting porous scaffolds, simply by incorporating IGF-1–loaded MB (MB-IGF-1) with polymer solution before phase separation. In vitro such MB-IGF-1 scaffolds were able to promote cell growth to a much greater extent than scaffold soaked in IGF-1, confirming the bioactivity of the released IGF-1. Further, such MB-IGF-1 scaffolds elicited IGF-1–specific collagen production in the surrounding tissue in vivo. This novel growth factor–eluting scaffold fabrication procedure can be used to deliver a range of single or combination of bioactive biomolecules to substantially promote cell growth and function in degradable scaffold. PMID:19327002

  5. A primary role for release factor 3 in quality control during translation elongation in Escherichia coli.

    PubMed

    Zaher, Hani S; Green, Rachel

    2011-10-14

    Release factor 3 (RF3) is a GTPase found in a broad range of bacteria where it is thought to play a critical "recycling" role in translation by facilitating the removal of class 1 release factors (RF1 and RF2) from the ribosome following peptide release. More recently, RF3 was shown in vitro to stimulate a retrospective editing reaction on the bacterial ribosome wherein peptides carrying mistakes are prematurely terminated during protein synthesis. Here, we examine the role of RF3 in the bacterial cell and show that the deletion of this gene sensitizes cells to other perturbations that reduce the overall fidelity of protein synthesis. We further document substantial effects on mRNA stability and protein expression using reporter systems, native mRNAs and proteins. We conclude that RF3 plays a primary role in vivo in specifying the fidelity of protein synthesis thus impacting overall protein quantity and quality.

  6. Potentiation of cytotoxic chemotherapy by growth hormone-releasing hormone agonists

    PubMed Central

    Jaszberenyi, Miklos; Rick, Ferenc G.; Popovics, Petra; Block, Norman L.; Zarandi, Marta; Cai, Ren-Zhi; Vidaurre, Irving; Szalontay, Luca; Jayakumar, Arumugam R.; Schally, Andrew V.

    2014-01-01

    The dismal prognosis of malignant brain tumors drives the development of new treatment modalities. In view of the multiple activities of growth hormone-releasing hormone (GHRH), we hypothesized that pretreatment with a GHRH agonist, JI-34, might increase the susceptibility of U-87 MG glioblastoma multiforme (GBM) cells to subsequent treatment with the cytotoxic drug, doxorubicin (DOX). This concept was corroborated by our findings, in vivo, showing that the combination of the GHRH agonist, JI-34, and DOX inhibited the growth of GBM tumors, transplanted into nude mice, more than DOX alone. In vitro, the pretreatment of GBM cells with JI-34 potentiated inhibitory effects of DOX on cell proliferation, diminished cell size and viability, and promoted apoptotic processes, as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide proliferation assay, ApoLive-Glo multiplex assay, and cell volumetric assay. Proteomic studies further revealed that the pretreatment with GHRH agonist evoked differentiation decreasing the expression of the neuroectodermal stem cell antigen, nestin, and up-regulating the glial maturation marker, GFAP. The GHRH agonist also reduced the release of humoral regulators of glial growth, such as FGF basic and TGFβ. Proteomic and gene-expression (RT-PCR) studies confirmed the strong proapoptotic activity (increase in p53, decrease in v-myc and Bcl-2) and anti-invasive potential (decrease in integrin α3) of the combination of GHRH agonist and DOX. These findings indicate that the GHRH agonists can potentiate the anticancer activity of the traditional chemotherapeutic drug, DOX, by multiple mechanisms including the induction of differentiation of cancer cells. PMID:24379381

  7. Rita Levi-Montalcini: the discovery of nerve growth factor and modern neurobiology.

    PubMed

    Aloe, Luigi

    2004-07-01

    The remarkable accomplishments in developmental neurobiology within the past 60 years have depended on two things: (i) a succession of original histochemical and immunohistochemical methodologies for identifying pathways in the nervous system with increasing precision and sensitivity, and (ii) the discovery of growth factors for neurons. Growth factors are naturally occurring, essential biological mediators that promote cell growth, differentiation, survival and function in specific nerve cell populations. The discovery of nerve growth factor (NGF) by Rita Levi-Montalcini in the 1950s represents an important milestone in the processes that led to modern cell biology. NGF was the first growth factor identified, for its action on the morphological differentiation of neural-crest-derived nerve cells. Later, its effect on neuronal cells of the peripheral and central nervous systems, and on several non-neuronal cells was also determined. Thus, Levi-Montalcini's work on NGF represents, as acknowledged by the Nobel Prize Assembly in its press release of 13 October 1986, "a fascinating example of how a skilled observer can create a concept out of apparent chaos".

  8. Strategies for Controlled Delivery of Growth Factors and Cells for Bone Regeneration

    PubMed Central

    Vo, Tiffany N.; Kasper, F. Kurtis; Mikos, Antonios G.

    2012-01-01

    The controlled delivery of growth factors and cells within biomaterial carriers can enhance and accelerate functional bone formation. The carrier system can be designed with preprogrammed release kinetics to deliver bioactive molecules in a localized, spatiotemporal manner most similar to the natural wound healing process. The carrier can also act as an extracellular matrix-mimicking substrate for promoting osteoprogenitor cellular infiltration and proliferation for integrative tissue repair. This review discusses the role of various regenerative factors involved in bone healing and their appropriate combinations with different delivery systems for augmenting bone regeneration. The general requirements of protein, cell and gene therapy are described, with elaboration on how the selection of materials, configurations and processing affects growth factor and cell delivery and regenerative efficacy in both in vitro and in vivo applications for bone tissue engineering. PMID:22342771

  9. Recombinant gamma interferon causes neutrophil migration mediated by the release of a macrophage neutrophil chemotactic factor.

    PubMed Central

    Ribeiro, R. A.; Cunha, F. Q.; Ferreira, S. H.

    1990-01-01

    A dose-dependent neutrophil migration was observed following the injection of purified (Hu IFN-gamma) or recombinant (rIFN-gamma) human gamma interferon into rat peritoneal cavities. This finding contrasts with their inability to cause chemotaxis in vitro in the Boyden chamber. Neutrophil migration into peritoneal cavities and subcutaneous air pouches induced by both preparations of interferon was abolished by pretreatment of the animals with dexamethasone. IFN-gamma-induced neutrophil migration was enhanced when the macrophage population of the peritoneal cavities was increased by previous injection of thioglycollate and reduced by peritoneal lavage. Macrophage monolayers pretreated either with rIFN-gamma or with lipopolysaccharide from E. coli release into the supernatant a factor that stimulates neutrophil recruitment in animals treated with dexamethasone. Dexamethasone blocked this release but did not affect the neutrophil recruitment induced by this factor. These results suggest that IFN-gamma-induced neutrophil migration in vivo may be mediated by the release from resident macrophages of a neutrophil chemotactic factor and that dexamethasone blockade of neutrophil recruitment by IFN-gamma is due to inhibition of the release of this factor. PMID:2119790

  10. 77 FR 4227 - Implantation or Injectable Dosage Form New Animal Drugs; Gonadotropin Releasing Factor Analog...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-27

    ... HUMAN SERVICES Food and Drug Administration 21 CFR Part 522 Implantation or Injectable Dosage Form New... gonadotropin releasing factor analog-diphtheria toxoid conjugate injectable solution. DATES: This rule is...: PART 522--IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS 0 1. The authority citation for...

  11. Ethanol and corticotropin releasing factor receptor modulation of central amygdala neurocircuitry: An update and future directions.

    PubMed

    Silberman, Yuval; Winder, Danny G

    2015-05-01

    The central amygdala is a critical brain region for many aspects of alcohol dependence. Much of the work examining the mechanisms by which the central amygdala mediates the development of alcohol dependence has focused on the interaction of acute and chronic ethanol with central amygdala corticotropin releasing factor signaling. This work has led to a great deal of success in furthering the general understanding of central amygdala neurocircuitry and its role in alcohol dependence. Much of this work has primarily focused on the hypothesis that ethanol utilizes endogenous corticotropin releasing factor signaling to upregulate inhibitory GABAergic transmission in the central amygdala. Work that is more recent suggests that corticotropin releasing factor also plays an important role in mediating anxiety-like behaviors via the enhancement of central amygdala glutamatergic transmission, implying that ethanol/corticotropin releasing factor interactions may modulate excitatory neurotransmission in this brain region. In addition, a number of studies utilizing optogenetic strategies or transgenic mouse lines have begun to examine specific central amygdala neurocircuit dynamics and neuronal subpopulations to better understand overall central amygdala neurocircuitry and the role of neuronal subtypes in mediating anxiety-like behaviors. This review will provide a brief update on this literature and describe some potential future directions that may be important for the development of better treatments for alcohol addiction.

  12. Hydroxyeicosatetraenoic acids released through the cytochrome P-450 pathway regulate 3T6 fibroblast growth.

    PubMed

    Nieves, Diana; Moreno, Juan José

    2006-12-01

    Eicosanoids participate in the regulation of cellular proliferation. Thus, we observed that prostaglandin E(2) interaction with membrane receptors is involved in the control of 3T6 fibroblast growth induced by serum. However, our results suggested that another arachidonic acid pathway might be implicated in these events. Our results show that 3T6 fibroblasts synthesized hydroxyeicosatetraenoic acids (HETEs) such as 12-HETE through the cytochrome P-450 (CYP450) pathway. However, 3T6 fibroblasts did not produce leukotriene B(4) (LTB(4)), and lipoxygenase inhibitors and LT antagonists failed to inhibit 3T6 fibroblast growth induced by FBS. In contrast, we observed that CYP450 inhibitors such as SKF-525A, 17-octadecynoic acid, 1-aminobenzotriazole, and 6-(2-propargyloxyphenyl)hexanoic acid reduced 12(S)-HETE levels, 3T6 fibroblast growth, and DNA synthesis induced by FBS. The impairment of DNA synthesis and 3T6 fibroblast growth induced by SKF-525A were reversed by exogenous addition of HETEs. Moreover, we report that 5-HETE, 12(S)-HETE, and 15(S)-HETE are mitogenic on 3T6 fibroblast in the absence of another growth factor, and this effect was dependent on the activation of the phosphatidylinositol-3-kinase pathway. In conclusion, our results show that HETEs, probably produced by CYP450, are involved in the control of 3T6 fibroblast growth.

  13. Insulin-like growth factors act synergistically with basic fibroblast growth factor and nerve growth factor to promote chromaffin cell proliferation.

    PubMed Central

    Frödin, M; Gammeltoft, S

    1994-01-01

    We have investigated the effects of insulin-like growth factors (IGFs), basic fibroblast growth factor (bFGF), and nerve growth factor (NGF) on DNA synthesis in cultured chromaffin cells from fetal, neonatal, and adult rats by using 5-bromo-2'-deoxyuridine (BrdUrd) pulse labeling for 24 or 48 h and immunocytochemical staining of cell nuclei. After 6 days in culture in the absence of growth factors, nuclear BrdUrd incorporation was detected in 30% of fetal chromaffin cells, 1.5% of neonatal cells, and 0.1% of adult cells. Addition of 10 nM IGF-I or IGF-II increased the fraction of BrdUrd-labeled nuclei to 50% of fetal, 20% of neonatal, and 2% of adult chromaffin cells. The ED50 value of IGF-I- and IGF-II-stimulated BrdUrd labeling in neonatal chromaffin cells was 0.3 nM and 0.8 nM, respectively. In neonatal and adult chromaffin cells, addition of 1 nM bFGF or 2 nM NGF stimulated nuclear BrdUrd incorporation to approximately the same level as 10 nM IGF-I or IGF-II. However, the response to bFGF or NGF in combination with either IGF-I or IGF-II was more than additive, indicating that the combined effect of the IGFs and bFGF or NGF is synergistic. The degree of synergism was 2- to 4-fold in neonatal chromaffin cells and 10- to 20-fold in adult chromaffin cells compared with the effect of each growth factor alone. In contrast, the action of bFGF and NGF added together in the absence of IGFs was not synergistic or additive. IGF-II acted also as a survival factor on neonatal chromaffin cells and the cell survival was further improved when bFGF or NGF was added together with IGF-II. In conclusion, we propose that IGF-I and IGF-II act in synergy with bFGF and NGF to stimulate proliferation and survival of chromaffin cells during neonatal growth and adult maintenance of the adrenal medulla. Our findings may have implications for improving the survival of chromaffin cell implants in diseased human brain. PMID:8127879

  14. Growth Hormone-Releasing Hormone and Its Analogues: Significance for MSCs-Mediated Angiogenesis

    PubMed Central

    Tao, Quanwei; Ma, Qunchao; Chen, Huiqiang; Wang, Jian'an

    2016-01-01

    Mesenchymal stromal cells (MSCs) are promising candidates for regenerative medicine because of their multipotency, immune-privilege, and paracrine properties including the potential to promote angiogenesis. Accumulating evidence suggests that the inherent properties of cytoprotection and tissue repair by native MSCs can be enhanced by various preconditioning stimuli implemented prior to cell transplantation. Growth hormone-releasing hormone (GHRH), a stimulator in extrahypothalamus systems including tumors, has attracted great attentions in recent years because GHRH and its agonists could promote angiogenesis in various tissues. GHRH and its agonists are proangiogenic in responsive tissues including tumors, and GHRH antagonists have been tested as antitumor agents through their ability to suppress angiogenesis and cell growth. GHRH-R is expressed by MSCs and evolving work from our laboratory indicates that treatment of MSCs with GHRH agonists prior to cell transplantation markedly enhanced the angiogenic potential and tissue reparative properties of MSCs through a STAT3 signaling pathway. In this review we summarized the possible effects of GHRH analogues on cell growth and development, as well as on the proangiogenic properties of MSCs. We also discussed the relationship between GHRH analogues and MSC-mediated angiogenesis. The analyses provide new insights into molecular pathways of MSCs-based therapies and their augmentation by GHRH analogues. PMID:27774107

  15. Inhibitory effect of a rhizobitoxine analog on bud growth after release from dormancy.

    PubMed

    Zimmerman, R H; Lieberman, M; Broome, O C

    1977-02-01

    Application of the ethoxy analog of rhizobitoxine (l-2-amino-4-[2'-aminoethoxy]-trans-3-butenoic acid), an inhibitor of ethylene biosynthesis, inhibited growth of apple, crabapple, and apricot buds released from dormancy by chilling or by treatment with benzyladenine. When tea crabapple (Malus hupehensis [Pamp.] Rehd.) buds were sprayed once with 8.8 x 10(-3)m benzyladenine, ethylene production by the buds increased significantly 24 to 48 hours after benzyladenine treatment. Application of the rhizobitoxine analog to the buds at the time of benzyladenine treatment reduced ethylene evolution to the level of the controls for up to 2 weeks after treatment. Increase in bud weight was inhibited also but to a lesser extent. These data suggest that growth of buds is accompanied by ethylene production and that the inhibition of ethylene biosynthesis also inhibits bud growth. Since additional metabolic effects result from the action of the rhizobitoxine analog, no firm conclusions on its role can be drawn at this time.

  16. Interactions between fibroblast growth factors and Notch regulate neuronal differentiation.

    PubMed

    Faux, C H; Turnley, A M; Epa, R; Cappai, R; Bartlett, P F

    2001-08-01

    The differentiation of precursor cells into neurons has been shown to be influenced by both the Notch signaling pathway and growth factor stimulation. In this study, the regulation of neuronal differentiation by these mechanisms was examined in the embryonic day 10 neuroepithelial precursor (NEP) population. By downregulating Notch1 expression and by the addition of a Delta1 fusion protein (Delta Fc), it was shown that signaling via the Notch pathway inhibited neuron differentiation in the NEP cells, in vitro. The expression of two of the Notch receptor homologs, Notch1 and Notch3, and the ligand Delta1 in these NEP cells was found to be influenced by a number of different growth factors, indicating a potential interaction between growth factors and Notch signaling. Interestingly, none of the growth factors examined promoted neuron differentiation; however, the fibroblast growth factors (FGFs) 1 and 2 potently inhibited differentiation. FGF1 and FGF2 upregulated the expression of Notch and decreased expression of Delta1 in the NEP cells. In addition, the inhibitory response of the cells to the FGFs could be overcome by downregulating Notch1 expression and by disrupting Notch cleavage and signaling by the ablation of the Presenilin1 gene. These results indicate that FGF1 and FGF2 act via the Notch pathway, either directly or indirectly, to inhibit differentiation. Thus, signaling through the Notch receptor may be a common regulator of neuronal differentiation within the developing forebrain.

  17. Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?

    PubMed

    Soliman, Ashraf; De Sanctis, Vincenzo; Elalaily, Rania; Bedair, Said

    2014-11-01

    Puberty is a period of development characterized by partially concurrent changes which includes growth acceleration, alteration in body composition and appearance of secondary sex characteristics. Puberty is characterized by an acceleration and then deceleration in skeletal growth. The initiation, duration and amount of growth vary considerably during the growth spurt. Pubertal growth and biological maturation are dynamic processes regulated by a variety of genetic and environmental factors. Changes in skeletal maturation and bone mineral accretion concomitant with the stage of pubertal development constitute essential components in the evaluation of growth during this pubertal period. Genetic, endocrine and nutritional factors and ethnicity contribute variably to the amount of growth gained during this important period of rapid changes. Many studies investigated the possibility of increasing pubertal growth to gain taller final adult height in adolescents with idiopathic short stature (ISS). The pattern of pubertal growth, its relation to sex maturity rating and factors affecting them has been addressed in this review. The results of different trials to increase final adult height of adolescents using different hormones have been summarized. These data enables Endocrinologists to give in-depth explanations to patients and families about the efficacy and clinical significance as well as the safety of using these therapies in the treatment of adolescents with ISS.

  18. Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?

    PubMed Central

    Soliman, Ashraf; De Sanctis, Vincenzo; Elalaily, Rania; Bedair, Said

    2014-01-01

    Puberty is a period of development characterized by partially concurrent changes which includes growth acceleration, alteration in body composition and appearance of secondary sex characteristics. Puberty is characterized by an acceleration and then deceleration in skeletal growth. The initiation, duration and amount of growth vary considerably during the growth spurt. Pubertal growth and biological maturation are dynamic processes regulated by a variety of genetic and environmental factors. Changes in skeletal maturation and bone mineral accretion concomitant with the stage of pubertal development constitute essential components in the evaluation of growth during this pubertal period. Genetic, endocrine and nutritional factors and ethnicity contribute variably to the amount of growth gained during this important period of rapid changes. Many studies investigated the possibility of increasing pubertal growth to gain taller final adult height in adolescents with idiopathic short stature (ISS). The pattern of pubertal growth, its relation to sex maturity rating and factors affecting them has been addressed in this review. The results of different trials to increase final adult height of adolescents using different hormones have been summarized. These data enables Endocrinologists to give in-depth explanations to patients and families about the efficacy and clinical significance as well as the safety of using these therapies in the treatment of adolescents with ISS. PMID:25538878

  19. Cytokine and Growth Factor Responses After Radiotherapy for Localized Ependymoma

    SciTech Connect

    Merchant, Thomas E. Li Chenghong; Xiong Xiaoping; Gaber, M. Waleed

    2009-05-01

    Purpose: To determine the time course and clinical significance of cytokines and peptide growth factors in pediatric patients with ependymoma treated with postoperative radiotherapy (RT). Methods and Materials: We measured 15 cytokines and growth factors (fibroblast growth factor, epidermal growth factor, vascular endothelial growth factor [VEGF], interleukin [IL]-1{beta}, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, interferon-{gamma}, tumor necrosis factor-{alpha}, granulocyte-macrophage colony-stimulating factor, monocyte chemoattractant protein-1, and macrophage inflammatory protein-{alpha}) from 30 patients before RT and 2 and 24 h, weekly for 6 weeks, and at 3, 6, 9, and 12 months after the initiation of RT. Two longitudinal models for the trend of log-transformed measurements were fitted, one during treatment and one through 12 months. Results: During RT, log IL-8 declined at a rate of -0.10389/wk (p = 0.0068). The rate of decline was greater (p = 0.028) for patients with an infratentorial tumor location. The decline in IL-8 after RT was significant when stratified by infratentorial tumor location (p = 0.0345) and more than one surgical procedure (p = 0.0272). During RT, the decline in log VEGF was significant when stratified by the presence of a ventriculoperitoneal shunt. After RT, the log VEGF declined significantly at a rate of -0.06207/mo. The decline was significant for males (p = 0.0222), supratentorial tumors (p = 0.0158), one surgical procedure (p = 0.0222), no ventriculoperitoneal shunt (p = 0.0005), and the absence of treatment failure (p = 0.0028). Conclusion: The pro-inflammatory cytokine IL-8 declined significantly during RT and the decline differed according to tumor location. The angiogenesis factor VEGF declined significantly during the 12 months after RT. The decline was greater in males, those without a ventriculoperitoneal shunt, and in those with favorable disease factors, including one surgical procedure, supratentorial tumor location, and

  20. Physiological factors of atrial natriuretic polypeptide release and its neural regulation in conscious dogs.

    PubMed

    Nishida, Y; Miyata, A; Morita, H; Hosomi, H

    1988-12-01

    We have examined physiological factors in atrial natriuretic polypeptide (ANP) release and whether or not the cardiac nerves control release of ANP. Two possible factors were tested, an increase in plasma sodium level (PNa) and an increase in atrial pressure. Injection of 1.0 or 2.0 mEq/kg of sodium ions elevated PNa by 5.3 +/- 0.3 or 7.3 +/- 0.4 mEq/L, respectively, but plasma ANP level (PANP) did not change. Infusion of 18 ml/kg of 3% Dextran-40 over 5 min increased mean left atrial pressure (MLAP) by 7.6 +/- 0.9 mmHg. PANP increased from 206 +/- 17 pg/ml to 260 +/- 25 pg/ml, which was not significant. PANP, corrected for hemodilution, significantly increased to 348 +/- 34 pg/ml. These results suggest that PNa increase does not promote ANP release, but that an atrial pressure increase does. This transient volume load did not induce full response of the ANP releasing system. A prolonged volume load for 45 min increased corrected PANP to 435 +/- 73 pg/ml. A close linear correlation was found between the increases in MLAP and PANP. These facts indicate that prolonged volume expansion is necessary to induce full response of the ANP releasing system. Complete cardiac denervation did not affect the tonic level of plasma ANP, volume expansion-induced increase in PANP, or the sensitivity of the ANP releasing system. Thus we conclude that the cardiac nerves do not control ANP release caused by volume expansion.

  1. Hyaluronan based porous nano-particles enriched with growth factors for the treatment of ulcers: a placebo-controlled study.

    PubMed

    Zavan, B; Vindigni, V; Vezzù, K; Zorzato, G; Luni, C; Abatangelo, G; Elvassore, N; Cortivo, R

    2009-01-01

    The present study describes the production of hyaluronan based porous microparticles by a semi-continuous gas anti-solvent (GAS) precipitation process to be used as a growth factor delivery system for in vivo treatment of ulcers. Operative process conditions, such as pressure, nozzle diameter and HYAFF11 solution concentrations, were adjusted to optimize particle production in terms of morphology and size. Scanning electron microscopy (SEM) and light scattering demonstrated that porous nano-structured particles with a size of 300 and 900 nm had a high specific surface suitable for absorption of growth factors from the aqueous environment within the polymeric matrix. Water acted as a plasticizer, enhancing growth factor absorption. Water contents within the HYAFF11 matrix were analyzed by differential scanning calorimetry (DSC). The absorption process was developed using fluorescence dyes and growth factors. Immunohistochemical analysis confirmed the high efficiency of absorption of growth factor and a mathematical model was generated to quantify and qualify the in vitro kinetics of growth factor release within the polymeric matrix. In vivo experiments were performed with the aim to optimize timed and focal release of PDGF to promote optimal tissue repair and regeneration of full-thickness wounds.

  2. Growth factors in porcine full and partial thickness burn repair. Differing targets and effects of keratinocyte growth factor, platelet-derived growth factor-BB, epidermal growth factor, and neu differentiation factor.

    PubMed Central

    Danilenko, D. M.; Ring, B. D.; Tarpley, J. E.; Morris, B.; Van, G. Y.; Morawiecki, A.; Callahan, W.; Goldenberg, M.; Hershenson, S.; Pierce, G. F.

    1995-01-01

    The topical application of recombinant growth factors such as epidermal growth factor, platelet-derived growth factor-BB homodimer (rPDGF-BB), keratinocyte growth factor (rKGF), and neu differentiation factor has resulted in significant acceleration of healing in several animal models of wound repair. In this study, we established highly reproducible and quantifiable full and deep partial thickness porcine burn models in which burns were escharectomized 4 or 5 days postburn and covered with an occlusive dressing to replicate the standard treatment in human burn patients. We then applied these growth factors to assess their efficacy on several parameters of wound repair: extracellular matrix and granulation tissue production, percent reepithelialization, and new epithelial area. In full thickness burns, only rPDGF-BB and the combination of rPDGF-BB and rKGF induced significant changes in burn repair. rPDGF-BB induced marked extracellular matrix and granulation tissue production (P = 0.013) such that the burn defect was filled within several days of escharectomy, but had no effect on new epithelial area or reepithelialization. The combination of rPDGF-BB and rKGF in full thickness burns resulted in a highly significant increase in extracellular matrix and granulation tissue area (P = 0.0009) and a significant increase in new epithelial area (P = 0.007), but had no effect on reepithelialization. In deep partial thickness burns, rKGF induced the most consistent changes. Daily application of rKGF induced a highly significant increase in new epithelial area (P < 0.0001) but induced only a modest increase in reepithelialization (83.7% rKGF-treated versus 70.2% control; P = 0.016) 12 days postburn. rKGF also doubled the number of fully reepithelialized burns (P = 0.02) at 13 days postburn, at least partially because of marked stimulation of both epidermal and follicular proliferation as assessed by proliferating cell nuclear antigen expression. In situ hybridization for

  3. Advances in growth factor delivery for therapeutic angiogenesis.

    PubMed

    Said, Somiraa S; Pickering, J Geoffrey; Mequanint, Kibret

    2013-01-01

    Therapeutic angiogenesis is a new revascularization strategy involving the administration of growth factors to induce new vessel formation. The biology and delivery of angiogenic growth factors involved in vessel formation have been extensively studied but success in translating the angiogenic capacity of growth factors into benefits for vascular disease patients is still limited. This could be attributed to issues related to patient selection, growth factor delivery methods or lack of vessel maturation. Comprehensive understanding of the cellular and molecular cross-talk during the different stages of vascular development is needed for the design of efficient therapeutic strategies. The presentation of angiogenic factors either in series or in parallel using a strategy that mimics physiological events, such as concentration and spatio-temporal profiles, is an immediate requirement for functional blood vessel formation. This review provides an overview of the recent delivery strategies of angiogenic factors and discusses targeting neovascular maturation as a promising approach to induce stable and functional vessels for therapeutic angiogenesis.

  4. Hammerhead Ribozyme-Mediated Knockdown of mRNA for Fibrotic Growth Factors: Transforming Growth Factor-Beta 1 and Connective Tissue Growth Factor

    PubMed Central

    Robinson, Paulette M.; Blalock, Timothy D.; Yuan, Rong; Lewin, Alfred S.; Schultz, Gregory S.

    2013-01-01

    Excessive scarring (fibrosis) is a major cause of pathologies in multiple tissues, including lung, liver, kidney, heart, cornea, and skin. The transforming growth factor- β (TGF- β) system has been shown to play a key role in regulating the formation of scar tissue throughout the body. Furthermore, connective tissue growth factor (CTGF) has been shown to mediate most of the fibrotic actions of TGF- β, including stimulation of synthesis of extracellular matrix and differentiation of fibroblasts into myofibroblasts. Currently, no approved drugs selectively and specifically regulate scar formation. Thus, there is a need for a drug that selectively targets the TGF- β cascade at the molecular level and has minimal off-target side effects. This chapter focuses on the design of hammerhead ribozymes, measurement of kinetic activity, and assessment of knockdown mRNAs of TGF- β and CTGF in cell cultures. PMID:22131029

  5. Growth Factor Gradients via Microsphere Delivery in Biopolymer Scaffolds for Osteochondral Tissue Engineering

    PubMed Central

    Wang, Xiaoqin; Wenk, Esther; Zhang, Xiaohui; Meinel, Lorenz; Vunjak-Novakovic, Gordana; Kaplan, David L.

    2009-01-01

    Temporally and spatially controlled delivery of growth factors in polymeric scaffolds is crucial for engineering composite tissue structures, such as osteochondral constructs. In the present study, microsphere-mediated growth factor delivery in polymer scaffolds and its impact on osteochondral differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) was evaluated. Two growth factors, bone morphogenetic protein 2 (rhBMP-2) and insulin-like growth factor I (rhIGF-I), were incorporated as a single concentration gradient or reverse gradient combining two factors in the scaffolds. To assess the gradient making system and the delivery efficiency of polylactic-co-glycolic acid (PLGA) and silk fibroin microspheres, initially an alginate gel was fabricated into a cylinder shape with microspheres incorporated as gradients. Compared to PLGA microspheres, silk microspheres were more efficient in delivering rhBMP-2, probably due to sustained release of the growth factor, while less efficient in delivering rhIGF-I, likely due to loading efficiency. The growth factor gradients formed were shallow, inducing non-gradient trends in hMSC osteochondral differentiation. Aqueous-derived silk porous scaffolds were used to incorporate silk microspheres using the same gradient process. Both growth factors formed deep and linear concentration gradients in the scaffold, as shown by enzyme-linked immunosorbent assay (ELISA). After seeding with hMSCs and culturing for 5 weeks in a medium containing osteogenic and chondrogenic components, hMSCs exhibited osteogenic and chondrogenic differentiation along the concentration gradients of rhBMP-2 in the single gradient of rhBMP-2 and reverse gradient of rhBMP-2/rhIGF-I, but not the rhIGF-I gradient system, confirming that silk microspheres were more efficient in delivering rhBMP-2 than rhIGF-I for hMSCs osteochondrogenesis. This novel silk microsphere/scaffold system offers a new option for the delivery of multiple growth factors

  6. Heparin-conjugated gelatin as a growth factor immobilization scaffold.

    PubMed

    Nakamura, Shintaro; Kubo, Takafumi; Ijima, Hiroyuki

    2013-05-01

    Tissue engineering requires growth factors, cells and a scaffold to permit effective tissue regeneration. This study aimed to develop a scaffold with a focus on immobilizing growth factors within gelatin. We focused on the extracellular matrix and developed a heparin-conjugated gelatin (Hep-gela). Conjugation was confirmed using the alcian blue assay and X-ray diffraction patterns. The mechanical strength and stability of the Hep-gela gel in protease solution were improved compared with collagen gel. Hep-gela was able to immobilize vascular endothelial growth factor (VEGF) even in the presence of albumin, with an efficiency of 54.2%. Immobilized VEGF promoted proliferation of human umbilical vein endothelial cells. Hep-gela-immobilized VEGF maintained its native biological activity. In summary, Hep-gela has the potential to become an effective material in the field of regenerative medicine.

  7. Growth factors with heparin binding affinity in human synovial fluid

    SciTech Connect

    Hamerman, D.; Taylor, S.; Kirschenbaum, I.; Klagsbrun, M.; Raines, E.W.; Ross, R.; Thomas, K.A.

    1987-12-01

    Synovial effusions were obtained from the knees of 15 subjects with joint trauma, menisceal or ligamentous injury, or osteoarthritis. Heparin-Sepharose affinity chromatography of these synovial fluids revealed, in general, three major peaks of mitogenic activity as measured by incorporation of /sup 3/H-thymidine into 3T3 cells. Gradient elution patterns showed activities at 0.5M NaCl, which is characteristic of platelet derived growth factor, and at 1.1 M NaCl and 1.6M NaCl, indicative of acidic and basic fibroblast growth factors, respectively. The identities of these mitogenic fractions were confirmed by specific immunologic and receptor-binding assays. The presence of platelet derived, acidic and basic fibroblast growth factors in the synovial fluid may contribute to wound healing in the arthritic joint.

  8. Resistance to growth hormone releasing hormone and gonadotropins in Albright's hereditary osteodystrophy.

    PubMed

    Mantovani, Giovanna; Spada, Anna

    2006-05-01

    Heterozygous inactivating mutations in the Gs alpha gene cause Albright's hereditary osteo-dystrophy (AHO). Consistent with the observation that only maternally inherited mutations lead to resistance to hormone action (pseudohypoparathyroidism type Ia [PHP-Ia), recent studies have provided evidence for a predominant maternal origin of Gs alpha transcripts in endocrine organs, such as thyroid, gonad and pituitary. Accordingly, patients with PHP-Ia display variable degrees of resistance to parathyroid hormone (PTH), thyroid stimulating hormone (TSH), gonadotropins and growth hormone (GH) releasing hormone (GHRH). Although the incidence and the clinical and biochemical characteristics of PTH and TSH resistance have been widely investigated and described, the cause and significance of the reproductive dysfunction in AHO is still poorly understood. The clinical finding of alterations of GH secretion in these patients was described for the first time only 2 years ago. The present report briefly reviews the literature focusing on the actual knowledge about these last two subjects.

  9. Infergen Stimulated Macrophages Restrict Mycobacterium tuberculosis Growth by Autophagy and Release of Nitric Oxide

    PubMed Central

    Pahari, Susanta; Khan, Nargis; Aqdas, Mohammad; Negi, Shikha; Kaur, Jagdeep; Agrewala, Javed N.

    2016-01-01

    IFN alfacon-1 (Infergen) is a synthetic form of Interferon (IFN)-α2b. Infergen has immunomodulatory activity and is effective against hepatitis C virus. However, the effect of Infergen (IFG) on Mycobacterium tuberculosis (Mtb) has not yet been reported. Therefore, for the first time, we have studied the influence of IFG in constraining the survival of Mtb in human macrophages. We observed that IFG significantly enhanced the maturation and activation of macrophages. Further, it substantially augmented the secretion of IL-6, nitric oxide (NO) and antigen uptake. Moreover, macrophages exhibited remarkably higher bactericidal activity, as evidenced by reduction in the Mtb growth. Infergen-mediated mechanism was different from the type-1 interferons; since it worked through the activation of NF-κB, phosphorylation of STAT-3 and Akt-PI3K that improved the bactericidal activity through autophagy and NO release. In future, IFG immunotherapy can be a novel strategy for treating patients and controlling TB. PMID:28000752

  10. Plants Release Precursors of Histone Deacetylase Inhibitors to Suppress Growth of Competitors[OPEN

    PubMed Central

    Venturelli, Sascha; Belz, Regina G.; Kämper, Andreas; Berger, Alexander; von Horn, Kyra; Wegner, André; Böcker, Alexander; Zabulon, Gérald; Barneche, Fredy; Lauer, Ulrich M.; Bitzer, Michael

    2015-01-01

    To secure their access to water, light, and nutrients, many plant species have developed allelopathic strategies to suppress competitors. To this end, they release into the rhizosphere phytotoxic substances that inhibit the germination and growth of neighbors. Despite the importance of allelopathy in shaping natural plant communities and for agricultural production, the underlying molecular mechanisms are largely unknown. Here, we report that allelochemicals derived from the common class of cyclic hydroxamic acid root exudates directly affect the chromatin-modifying machinery in Arabidopsis thaliana. These allelochemicals inhibit histone deacetylases both in vitro and in vivo and exert their activity through locus-specific alterations of histone acetylation and associated gene expression. Our multilevel analysis collectively shows how plant-plant interactions interfere with a fundamental cellular process, histone acetylation, by targeting an evolutionarily highly conserved class of enzymes. PMID:26530086

  11. Cultured human foreskin fibroblasts produce a factor that stimulates their growth with properties similar to basic fibroblast growth factor

    SciTech Connect

    Story, M.T. )

    1989-05-01

    To determine if fibroblasts could be a source of fibroblast growth factor (FGF) in tissue, cells were initiated in culture from newborn human foreskin. Fibroblast cell lysates promoted radiolabeled thymidine uptake by cultured quiescent fibroblasts. Seventy-nine percent of the growth-promoting activity of lysates was recovered from heparin-Sepharose. The heparin-binding growth factor reacted on immunoblots with antiserum to human placenta-derived basic FGF and competed with iodinated basic FGF for binding to antiserum to (1-24)bFGF synthetic peptide. To confirm that fibroblasts were the source of the growth factor, cell lysates were prepared from cells incubated with radiolabeled methionine. Heparin affinity purified material was immunoprecipitated with basic FGF antiserum and electrophoresed. Radiolabeled material was detected on gel autoradiographs in the same molecular weight region as authentic iodinated basic FGF. The findings are consistant with the notion that cultured fibroblasts express basic FGF. As these cells also respond to the mitogen, it is possible that the regulation of their growth is under autocrine control. Fibroblasts may be an important source of the growth factor in tissue.

  12. Azapeptide analogues of the growth hormone releasing peptide 6 as cluster of differentiation 36 receptor ligands with reduced affinity for the growth hormone secretagogue receptor 1a.

    PubMed

    Proulx, Caroline; Picard, Émilie; Boeglin, Damien; Pohankova, Petra; Chemtob, Sylvain; Ong, Huy; Lubell, William D

    2012-07-26

    The synthetic hexapeptide growth hormone releasing peptide-6 (GHRP-6) exhibits dual affinity for the growth hormone secretagogue receptor 1a (GHS-R1a) and the cluster of differentiation 36 (CD36) receptor. Azapeptide GHRP-6 analogues have been synthesized, exhibiting micromolar affinity to the CD36 receptor with reduced affinity toward the GHS-R1a. A combinatorial split-and-mix approach furnished aza-GHRP-6 leads, which were further examined by alanine scanning. Incorporation of an aza-amino acid residue respectively at the D-Trp(2), Ala(3), or Trp(4) position gave aza-GHRP-6 analogues with reduced affinity toward the GHS-R1a by at least a factor of 100 and in certain cases retained affinity for the CD36 receptor. In the latter cases, the D-Trp(2) residue proved important for CD36 receptor affinity; however, His(1) could be replaced by Ala(1) without considerable loss of binding. In a microvascular sprouting assay using a choroid explant, [azaTyr(4)]-GHRP-6 (15), [Ala(1), azaPhe(2)]-GHRP-6 (16), and [azaLeu(3), Ala(6)]-GHRP-6 (33) all exhibited antiangiogenic activity.

  13. Thyroid Hormone and Estrogen Regulate Exercise-Induced Growth Hormone Release

    PubMed Central

    Ignacio, Daniele Leão; da S. Silvestre, Diego H.; Cavalcanti-de-Albuquerque, João Paulo Albuquerque; Louzada, Ruy Andrade

    2015-01-01

    Growth hormone (GH) regulates whole body metabolism, and physical exercise is the most potent stimulus to induce its secretion in humans. The mechanisms underlying GH secretion after exercise remain to be defined. The aim of this study was to elucidate the role of estrogen and pituitary type 1 deiodinase (D1) activation on exercise-induced GH secretion. Ten days after bilateral ovariectomy, animals were submitted to 20 min of treadmill exercise at 75% of maximum aerobic capacity and tissues were harvested immediately or 30 min after exercise. Non-exercised animals were used as controls. A significant increase in D1 activity occurred immediately after exercise (~60%) in sham-operated animals and GH was higher (~6-fold) 30 min after exercise. Estrogen deficient rats exhibited basal levels of GH and D1 activity comparable to those found in control rats. However, after exercise both D1 activity and serum GH levels were blunted compared to sedentary rats. To understand the potential cause-effect of D1 activation in exercise-induced GH release, we pharmacologically blocked D1 activity by propylthiouracil (PTU) injection into intact rats and submitted them to the acute exercise session. D1 inhibition blocked exercise-induced GH secretion, although basal levels were unaltered. In conclusion, estrogen deficiency impairs the induction of thyroid hormone activating enzyme D1 in the pituitary, and GH release by acute exercise. Also, acute D1 activation is essential for exercise-induced GH response. PMID:25874614

  14. The hypothalamic-pituitary response in SLE. Regulation of prolactin, growth hormone and cortisol release.

    PubMed

    Rovenský, J; Blazícková, S; Rauová, L; Jezová, D; Koska, J; Lukác, J; Vigas, M

    1998-01-01

    It has been suggested that neuroendocrine regulation plays an important role in the pathogenesis and activation of autoimmune diseases. The aim of this investigation was to clarify the hypothalamic-pituitary response to a well-defined stimulus under standardised conditions in patients with SLE. Plasma concentrations of prolactin (PRL), growth hormone (GH) and cortisol were determined in venous blood drawn through an indwelling cannula during insulin-induced hypoglycaemia (0.1 U/kg b.w., i.v.) in ten patients and in 12 age-, gender- and weight-matched healthy subjects. Basal PRL concentrations were higher in patients vs healthy controls (12 vs 6 ng/ml, P < 0.01), though still within the physiological range. Insulin-induced plasma PRL and GH were significantly increased both in patients and healthy subjects; however, the increments or areas under the curves were not different in the two groups. Plasma cortisol response showed moderate attenuation in patients. Sensitivity of pituitary lactotrothrops to thyrotropin-releasing hormone (TRH) administration (200 microg, i.v.) was the same in patients and control subjects. In SLE patients with low activity of the disease the sensitivity of pituitary PRL release to TRH administration remained unchanged. The hypothalamic response to stress stimulus (hypoglycaemia) was comparable in patients and healthy subjects.

  15. Insulin-like growth factors in the peripheral nervous system.

    PubMed

    Sakowski, Stacey A; Feldman, Eva L

    2012-06-01

    Insulin-like growth factors (IGFs) play an integral role in development, growth, and survival. This article details the current understanding of the effects of IGFs in the peripheral nervous system (PNS) during health and disease, and introduces how the IGF system regulates PNS development and impacts growth and survival of PNS cells. Also discussed are implications of IGF signaling in neurodegeneration and the status and prospects of IGF therapies for PNS conditions. There is substantial support for the application of IGF therapies in the treatment of PNS injury and disease.

  16. Acceleration of wound healing by growth hormone-releasing hormone and its agonists.

    PubMed

    Dioufa, Nikolina; Schally, Andrew V; Chatzistamou, Ioulia; Moustou, Evi; Block, Norman L; Owens, Gary K; Papavassiliou, Athanasios G; Kiaris, Hippokratis

    2010-10-26

    Despite the well-documented action of growth hormone-releasing hormone (GHRH) on the stimulation of production and release of growth hormone (GH), the effects of GHRH in peripheral tissues are incompletely explored. In this study, we show that GHRH plays a role in wound healing and tissue repair by acting primarily on wound-associated fibroblasts. Mouse embryonic fibroblasts (MEFs) in culture and wound-associated fibroblasts in mice expressed a splice variant of the receptors for GHRH (SV1). Exposure of MEFs to 100 nM and 500 nM GHRH or the GHRH agonist JI-38 stimulated the expression of α-smooth muscle actin (αSMA) based on immunoblot analyses as well as the expression of an αSMA-β-galactosidase reporter transgene in primary cultures of fibroblasts isolated from transgenic mice. Consistent with this induction of αSMA expression, results of transwell-based migration assays and in vitro wound healing (scratch) assays showed that both GHRH and GHRH agonist JI-38 stimulated the migration of MEFs in vitro. In vivo, local application of GHRH or JI-38 accelerated healing in skin wounds of mice. Histological evaluation of skin biopsies showed that wounds treated with GHRH and JI-38 were both characterized by increased abundance of fibroblasts during the early stages of wound healing and accelerated reformation of the covering epithelium at later stages. These results identify another function of GHRH in promoting skin tissue wound healing and repair. Our findings suggest that GHRH may have clinical utility for augmenting healing of skin wounds resulting from trauma, surgery, or disease.

  17. Inhibition of platelet-derived growth factor signaling prevents muscle fiber growth during skeletal muscle hypertrophy.

    PubMed

    Sugg, Kristoffer B; Korn, Michael A; Sarver, Dylan C; Markworth, James F; Mendias, Christopher L

    2017-03-01

    The platelet-derived growth factor receptors alpha and beta (PDGFRα and PDGFRβ) mark fibroadipogenic progenitor cells/fibroblasts and pericytes in skeletal muscle, respectively. While the role that these cells play in muscle growth and development has been evaluated, it was not known whether the PDGF receptors activate signaling pathways that control transcriptional and functional changes during skeletal muscle hypertrophy. To evaluate this, we inhibited PDGFR signaling in mice subjected to a synergist ablation muscle growth procedure, and performed analyses 3 and 10 days after induction of hypertrophy. The results from this study indicate that PDGF signaling is required for fiber hypertrophy, extracellular matrix production, and angiogenesis that occur during muscle growth.

  18. Complementary Effects of Two Growth Factors in Multifunctionalized Silk Nanofibers for Nerve Reconstruction

    PubMed Central

    Jose, Rodrigo R.; Vigneron, Pascale; Bresson, Damien; Fitzpatrick, Vincent; Marin, Frédéric; Kaplan, David L.; Egles, Christophe

    2014-01-01

    With the aim of forming bioactive guides for peripheral nerve regeneration, silk fibroin was electrospun to obtain aligned nanofibers. These fibers were functionalized by incorporating Nerve Growth Factor (NGF) and Ciliary NeuroTrophic Factor (CNTF) during electrospinning. PC12 cells grown on the fibers confirmed the bioavailability and bioactivity of the NGF, which was not significantly released from the fibers. Primary neurons from rat dorsal root ganglia (DRGs) were grown on the nanofibers and anchored to the fibers and grew in a directional fashion based on the fiber orientation, and as confirmed by growth cone morphology. These biofunctionalized nanofibers led to a 3-fold increase in neurite length at their contact, which was likely due to the NGF. Glial cell growth, alignment and migration were stimulated by the CNTF in the functionalized nanofibers. Organotypic culture of rat fetal DRGs confirmed the complementary effect of both growth factors in multifunctionalized nanofibers, which allowed glial cell migration, alignment and parallel axonal growth in structures resembling the ‘bands of Bungner’ found in situ. Graftable multi-channel conduits based on biofunctionalized aligned silk nanofibers were developed as an organized 3D scaffold. Our bioactive silk tubes thus represent new options for a biological and biocompatible nerve guidance conduit. PMID:25313579

  19. Constructing a blood vessel on the porous scaffold modified with vascular endothelial growth factor and basic fibroblast growth factor

    NASA Astrophysics Data System (ADS)

    Sevostyanova, V. V.; Matveeva, V. G.; Antonova, L. V.; Velikanova, E. A.; Shabaev, A. R.; Senokosova, E. A.; Krivkina, E. O.; Vasyukov, G. Yu.; Glushkova, T. V.; Kudryavtseva, Yu. A.; Barbarash, O. L.; Barbarash, L. S.

    2016-11-01

    Incorporation of the growth factors into biodegradable polymers is a promising approach for the fabrication of tissue-engineered vascular grafts. Here we blended poly(ɛ-caprolactone) (PCL) with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) following incorporation of either vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF) and then fabricated electrospun 2 mm diameter vascular grafts. Grafts without the growth factors were used as a control group. Structure of the grafts was assessed utilizing scanning electron microscopy. We further implanted our grafts into rat abdominal aorta for 1 and 3 months with the aim to test endothelialization, cell infiltration, and patency in vivo. Histological and immunofluorescence examination demonstrated enhanced endothelialization and cell infiltration of the grafts with either VEGF or bFGF compared to those without the growth factors. Grafts with VEGF showed higher patency compared to those with bFGF; however, bFGF promoted migration of smooth muscle cells and fibroblasts into the graft. Therefore, we conclude that incorporation of VEGF and bFGF into the inner and medial/outer layer, respectively, can be a promising option for the fabrication of tissue-engineered vascular grafts.

  20. Purification of an RNA polymerase II transcript release factor from Drosophila.

    PubMed

    Xie, Z; Price, D H

    1996-05-10

    Factor 2 was previously identified in Drosophila Kc cell nuclear extract (KcN) as an activity suppressing the appearance of long transcripts (Price, D. H., Sluder, A. E., and Greenleaf, A. L. (1987) J. Biol. Chem. 262, 3244-3255). A 154-kDa protein with factor 2 activity was purified to apparent homogeneity from KcN. An immobilized template assay indicated that factor 2 caused the release of transcripts by RNA polymerase II in an ATP-dependent manner. Some early elongation complexes were resistant to factor 2 action but became sensitive after treatment with 1 M KCl. In the absence of factor 2, transcription complexes still exhibited a low degree of processivity suggesting that factor 2 was only partially responsible for abortive elongation.

  1. Isolation and characterization of lipid-protein particles containing platelet factor 3 released from human platelets.

    PubMed Central

    Sandberg, H; Andersson, L O; Höglund, S

    1982-01-01

    Lipid-protein particles with platelet factor 3 measured by the Stypven clotting-time test [Hardisty & Hutton (1966) Br. J. Haematol. 12, 764-776] have been isolated from platelet-release supernatant. Starting material was washed platelets, which were released by treatment with collagen. Purification of the particles from other components in the release material was accomplished by gel filtration on Sepharose CL-4B followed by affinity chromatography on poly-L-lysine-Sepharose CL-4B gel. Chemical characterization showed that the particles were composed of 40% protein, 42% phospholipids, 13% cholesterol and 5% triacylglycerols. The phospholipid composition was 38% phosphatidylcholine, 25% phosphatidylethanolamine, 9% phosphatidylserine, 2% phosphatidic acid and 26% sphingomyelin. No carbohydrate was detected. Electron-microscopic studies revealed the presence of membranous particles with diameters between 70 and 170 nm. Images PLATE 1 Fig. 3. PMID:7103943

  2. Brain derived neurotrophic factor release from layer-by-layer coated agarose nerve guidance scaffolds.

    PubMed

    Lynam, Daniel A; Shahriari, Dena; Wolf, Kayla J; Angart, Phillip A; Koffler, Jacob; Tuszynski, Mark H; Chan, Christina; Walton, Patrick; Sakamoto, Jeffrey

    2015-05-01

    Agarose nerve guidance scaffolds (NGS) seeded with cells expressing brain derived neurotrophic factor (BDNF) have demonstrated robust nerve regeneration in the rat central nervous system. The purpose of this work was to explore whether agarose NGS coated with hydrogen-bonded layer-by-layer (HLbL) could provide an acellular method of delivering prolonged and consistent dosages of active BDNF. Our results show that HLbL-coated agarose NGS could release BDNF over 10days in consistent dosages averaging 80.5±12.5(SD)ng/mL. Moreover, the BDNF released from HLbL was confirmed active by in vitro cell proliferation assays. To our knowledge, this is the first report demonstrating that HLbL assembled onto a hydrogel can provide consistent, prolonged release of active BDNF in clinically relevant dosages.

  3. Cytokines and growth factors which regulate bone cell function

    NASA Astrophysics Data System (ADS)

    Seino, Yoshiki

    Everybody knows that growth factors are most important in making bone. Hormones enhance bone formation from a long distance. Growth factors promote bone formation as an autocrine or paracrine factor in nearby bone. BMP-2 through BMP-8 are in the TGF-β family. BMP makes bone by enchondral ossification. In bone, IGF-II is most abundant, second, TGF-β, and third IGF-I. TGF-β enhances bone formation mainly by intramembranous ossification in vivo. TGF-β affects both cell proliferation and differentiation, however, TGF-β mainly enhances bone formation by intramembranous ossification. Interestingly, TGF-β is increased by estrogen(E 2), androgen, vitamin D, TGF-β and FGF. IGF-I and IGF-II also enhance bone formation. At present it remains unclear why IGF-I is more active in bone formation than IGF-II, although IGF-II is more abundant in bone compared to IGF-I. However, if only type I receptor signal transduction promotes bone formation, the strong activity of IGF-I in bone formation is understandable. GH, PTH and E 2 promotes IGF-I production. Recent data suggest that hormones containing vitamin D or E 2 enhance bone formation through growth factors. Therefore, growth factors are the key to clarifying the mechanism of bone formation.

  4. Sprouty 2 binds ESCRT-II factor Eap20 and facilitates HIV-1 gag release.

    PubMed

    Medina, G N; Ehrlich, L S; Chen, M H; Khan, M B; Powell, M D; Carter, C A

    2011-07-01

    The four ESCRT (endocytic sorting complexes required for transport) complexes (ESCRT-0, -I, -II, and -III) normally operate sequentially in the trafficking of cellular cargo. HIV-1 Gag trafficking and release as virus-like particles (VLPs) require the participation of ESCRTs; however, its use of ESCRTs is selective and nonsequential. Specifically, Gag trafficking to release sites on the plasma membrane does not require ESCRT-0 or -II. It is known that a bypass of ESCRT-0 is achieved by the direct linkage of the ESCRT-I component, Tsg101, to the primary L domain motif (PTAP) in Gag and that bypass of ESCRT-II is achieved by the linkage of Gag to ESCRT-III through the adaptor protein Alix. However, the mechanism by which Gag suppresses the interaction of bound ESCRT-I with ESCRT-II is unknown. Here we show (i) that VLP release requires the steady-state level of Sprouty 2 (Spry2) in COS-1 cells, (ii) that Spry2 binds the ESCRT-II component Eap20, (iii) that binding Eap20 permits Spry2 to disrupt ESCRT-I interaction with ESCRT-II, and (iv) that coexpression of Gag with a Spry2 fragment that binds Eap20 increases VLP release. Spry2 also facilitated release of P7L-Gag (i.e., release in the absence of Tsg101 binding). In this case, rescue required the secondary L domain (YPX(n)L) in HIV-1 Gag that binds Alix and the region in Spry2 that binds Eap20. The results identify Spry2 as a novel cellular factor that facilitates release driven by the primary and secondary HIV-1 Gag L domains.

  5. Vascular endothelial growth factors: A comparison between invertebrates and vertebrates.

    PubMed

    Kipryushina, Yulia O; Yakovlev, Konstantin V; Odintsova, Nelly A

    2015-12-01

    This review aims to summarize recent data concerning the structure and role of the members of the vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor (VEGFR) families in the context of early development, organogenesis and regeneration, with a particular emphasis on the role of these factors in the development of invertebrates. Homologs of VEGF and/or VEGFR have been found in all Eumetazoa, in both Radiata and Bilateria, where they are expressed in the descendants of different germ layers and play a pivotal role in the development of animals with and without a vascular system. VEGF is a well-known angiogenesis regulator, but this factor also control cell migration during neurogenesis and the development of branching organs (the trachea) in invertebrate and vertebrate species. A possible explanation for the origin of Vegf/Vegfr in the animal kingdom and a pathway of Vegf/Vegfr evolution are discussed.

  6. Growth Factor Liberation and DPSC Response Following Dentine Conditioning.

    PubMed

    Sadaghiani, L; Gleeson, H B; Youde, S; Waddington, R J; Lynch, C D; Sloan, A J

    2016-10-01

    Liberation of the sequestrated bioactive molecules from dentine by the action of applied dental materials has been proposed as an important mechanism in inducing a dentinogenic response in teeth with viable pulps. Although adhesive restorations and dentine-bonding procedures are routinely practiced, clinical protocols to improve pulp protection and dentine regeneration are not currently driven by biological knowledge. This study investigated the effect of dentine (powder and slice) conditioning by etchants/conditioners relevant to adhesive restorative systems on growth factor solubilization and odontoblast-like cell differentiation of human dental pulp progenitor cells (DPSCs). The agents included ethylenediaminetetraacetic acid (EDTA; 10%, pH 7.2), phosphoric acid (37%, pH <1), citric acid (10%, pH 1.5), and polyacrylic acid (25%, pH 3.9). Growth factors were detected in dentine matrix extracts drawn by EDTA, phosphoric acid, and citric acid from powdered dentine. The dentine matrix extracts were shown to be bioactive, capable of stimulating odontogenic/osteogenic differentiation as observed by gene expression and phenotypic changes in DPSCs cultured in monolayer on plastic. Polyacrylic acid failed to solubilize proteins from powdered dentine and was therefore considered ineffective in triggering a growth factor-mediated response in cells. The study went on to investigate the effect of conditioning dentine slices on growth factor liberation and DPSC behavior. Conditioning by EDTA, phosphoric acid, and citric acid exposed growth factors on dentine and triggered an upregulation in genes associated with mineralized differentiation, osteopontin, and alkaline phosphatase in DPSCs cultured on dentine. The cells demonstrated odontoblast-like appearances with elongated bodies and long extracellular processes extending on dentine surface. However, phosphoric acid-treated dentine appeared strikingly less populated with cells, suggesting a detrimental impact on cell

  7. Cytotoxic T lymphocyte-dependent tumor growth inhibition by a vascular endothelial growth factor-superantigen conjugate

    SciTech Connect

    Sun, Qingwen; Jiang, Songmin; Han, Baohui; Sun, Tongwen; Li, Zhengnan; Zhao, Lina; Gao, Qiang; Sun, Jialin

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer We construct and purify a fusion protein VEGF-SEA. Black-Right-Pointing-Pointer VEGF-SEA strongly repressed the growth of murine solid sarcoma 180 (S180) tumors. Black-Right-Pointing-Pointer T cells driven by VEGF-SEA were accumulated around tumor cells bearing VEGFR by mice image model. Black-Right-Pointing-Pointer VEGF-SEA can serve as a tumor targeting agent and sequester CTLs into the tumor site. Black-Right-Pointing-Pointer The induced CTLs could release the cytokines, perforins and granzyme B to kill the tumor cells. -- Abstract: T cells are major lymphocytes in the blood and passengers across the tumor vasculature. If these T cells are retained in the tumor site, a therapeutic potential will be gained by turning them into tumor-reactive cytotoxic T lymphocytes (CTLs). A fusion protein composed of human vascular endothelial growth factor (VEGF) and staphylococcal enterotoxin A (SEA) with a D227A mutation strongly repressed the growth of murine solid sarcoma 180 (S180) tumors (control versus VEGF-SEA treated with 15 {mu}g, mean tumor weight: 1.128 g versus 0.252 g, difference = 0.876 g). CD4{sup +} and CD8{sup +} T cells driven by VEGF-SEA were accumulated around VEGFR expressing tumor cells and the induced CTLs could release the tumoricidal cytokines, such as interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). Meanwhile, intratumoral CTLs secreted cytolytic pore-forming perforin and granzyme B proteins around tumor cells, leading to the death of tumor cells. The labeled fusion proteins were gradually targeted to the tumor site in an imaging mice model. These results show that VEGF-SEA can serve as a tumor targeting agent and sequester active infiltrating CTLs into the tumor site to kill tumor cells, and could therefore be a potential therapeutical drug for a variety of cancers.

  8. Seed release by invasive thistles: the impact of plant and environmental factors

    PubMed Central

    Jongejans, Eelke; Pedatella, Nicholas M; Shea, Katriona; Skarpaas, Olav; Auhl, Richard

    2007-01-01

    Dispersal is a key process in biological studies of spatial dynamics, but the initiation of dispersal has often been neglected, despite strong indications that differential timing of dispersal can significantly affect dispersal distances. To investigate which plant and environmental factors determine the release of plumed seeds by the invasive thistles Carduus acanthoides and Carduus nutans, we exposed 192 flower heads of each species to increasing wind speeds in a full-factorial wind tunnel experiment with four air flow turbulence, three flower head wetness and two flower head temperature levels. The number of seed releases was highest under dry and turbulent conditions and from heads that had already lost a considerable number of seeds, but was not affected by flower head size, head angle or temperature. Inspection of the trials on video showed that higher wind speeds were needed to meet the seed release threshold in laminar flows and for C. acanthoides heads that had been wet for a longer time. Species differences were minimal, although seed release was more sensitive to lower levels of turbulence in the larger-headed and more open C. nutans heads. Knowledge of seed release biases towards weather conditions favourable for long-distance dispersal improves our understanding of the spread of invaders and allows managers to increase the efficiency of their containment strategies by applying them at crucial times. PMID:17666379

  9. Induction of release of tumor necrosis factor from human monocytes by staphylococci and staphylococcal peptidoglycans.

    PubMed Central

    Timmerman, C P; Mattsson, E; Martinez-Martinez, L; De Graaf, L; Van Strijp, J A; Verbrugh, H A; Verhoef, J; Fleer, A

    1993-01-01

    The role of cytokines in gram-positive infections is still relatively poorly defined. The purpose of this study was to establish whether or not intact staphylococci and purified peptidoglycans and peptidoglycan components derived from staphylococci are capable of stimulating the release of tumor necrosis factor (TNF) by human monocytes. We show here that intact staphylococci and purified peptidoglycans, isolated from three Staphylococcus epidermidis and three S. aureus strains, were indeed able to induce secretion of TNF by human monocytes in a concentration-dependent fashion. TNF release was detected by both enzyme immunoassay and the L929 fibroblast bioassay. In the enzyme immunoassay, a minimal concentration of peptidoglycan of 1 micrograms/ml was required to detect TNF release by monocytes, whereas in the bioassay a peptidoglycan concentration of 10 micrograms/ml was needed to detect a similar amount of TNF release. Peptidoglycan components such as the stem peptide, tetra- and pentaglycine, and muramyl dipeptide were unable to induce TNF release from human monocytes. PMID:8406805

  10. Differential in vitro phenotype pattern, transforming growth factor-beta(1) activity and mRNA expression of transforming growth factor-beta(1) in Apert osteoblasts.

    PubMed

    Locci, P; Baroni, T; Pezzetti, F; Lilli, C; Marinucci, L; Martinese, D; Becchetti, E; Calvitti, M; Carinci, F

    1999-09-01

    The phenotype of Apert osteoblasts differs from that of normal osteoblasts in the accumulation of macromolecules in the extracellular matrix. Apert osteoblasts increase type I collagen, fibronectin and glycosaminoglycans secretion compared with normal osteoblasts. Because the extracellular matrix macromolecule accumulation is greatly modulated by transforming growth factor-beta(1), we examined the ability of normal and Apert osteoblasts to secrete transforming growth factor-beta(1) by CCL-64 assay and to produce transforming growth factor-beta(1 )by analysis of the mRNA expression of transforming growth factor-beta(1). Northern blot analysis revealed an increased amount of transforming growth factor-beta(1) mRNA expression in Apert osteoblasts compared with normal ones. Moreover, the level of the active transforming growth factor-beta(1) isoform was higher in Apert than in normal media. In pathologic cells, the increase in transforming growth factor-beta(1) gene expression was associated with a parallel increase in the factor secreted into the medium. The level of transforming growth factor-beta(1) was decreased by the addition of basic fibroblast growth factor. Transforming growth factor-beta(1) is controlled temporally and spatially during skeletal tissue development and produces complex stimulatory and inhibitory changes in osteoblast functions. We hypothesise that in vitro differences between normal and Apert osteoblasts may be correlated to different transforming growth factor-beta(1) cascade patterns, probably due to an altered balance between transforming growth factor-beta(1) and basic fibroblast growth factor.

  11. Influence of Formulation Factors and Compression Force on Release Profile of Sustained Release Metoprolol Tablets using Compritol® 888ATO as Lipid Excipient

    PubMed Central

    Patere, Shilpa N.; Kapadia, Chhanda J.; Nagarsenker, Mangal S.

    2015-01-01

    Tablets containing metoprolol succinate and Compritol® 888ATO in the ratio of 1:2 yielded the desired sustained release profile in phosphate buffer pH 6.8 when evaluated using USP type II paddle apparatus and was selected as the optimized formulation. Robustness of optimized formulation was assessed by studying the effect of factors like varying source of metoprolol succinate and Compritol® 888ATO, compression force and hydroalcoholic dissolution medium on the release profile. No significant difference (P>0.05) in release profile was observed when metoprolol succinate from three different sources and Compritol® 888ATO from two different batches were used. Release profile of sustained release tablets of metoprolol succinate in media containing various concentrations of ethanol was comparable with media devoid of ethanol as evaluated by f2 test. This indicated that release profile of sustained release tablets of metoprolol succinate was reliable with no significant change due to variation in source of active pharmaceutical ingredient, particularly due to particle size distribution. Sustained release tablets of metoprolol succinate yielded release pattern within specifications irrespective of presence or absence of ethanol in the medium indicating that release properties of Compritol® 888ATO matrix are not affected by ethanol. Tablets compressed at compression force of <100 kg/cm2 exhibited low hardness with total porosity of 15.39% and significantly increased (P<0.05) metoprolol succinate release as compared to tablets compressed at 2000 kg/cm2 with 6.90% of total porosity revealing influence of compression force. Compritol® 888ATO holds great potential in providing reliable and controlled release profile of highly water soluble metoprolol succinate. PMID:26798179

  12. Specific involvement of gonadal hormones in the functional maturation of growth hormone releasing hormone (GHRH) neurons.

    PubMed

    Gouty-Colomer, Laurie-Anne; Méry, Pierre-François; Storme, Emilie; Gavois, Elodie; Robinson, Iain C; Guérineau, Nathalie C; Mollard, Patrice; Desarménien, Michel G

    2010-12-01

    Growth hormone (GH) is the key hormone involved in the regulation of growth and metabolism, two functions that are highly modulated during infancy. GH secretion, controlled mainly by GH releasing hormone (GHRH), has a characteristic pattern during postnatal development that results in peaks of blood concentration at birth and puberty. A detailed knowledge of the electrophysiology of the GHRH neurons is necessary to understand the mechanisms regulating postnatal GH secretion. Here, we describe the unique postnatal development of the electrophysiological properties of GHRH neurons and their regulation by gonadal hormones. Using GHRH-eGFP mice, we demonstrate that already at birth, GHRH neurons receive numerous synaptic inputs and fire large and fast action potentials (APs), consistent with effective GH secretion. Concomitant with the GH secretion peak occurring at puberty, these neurons display modifications of synaptic input properties, decrease in AP duration, and increase in a transient voltage-dependant potassium current. Furthermore, the modulation of both the AP duration and voltage-dependent potassium current are specifically controlled by gonadal hormones because gonadectomy prevented the maturation of these active properties and hormonal treatment restored it. Thus, GHRH neurons undergo specific developmental modulations of their electrical properties over the first six postnatal weeks, in accordance with hormonal demand. Our results highlight the importance of the interaction between the somatotrope and gonadotrope axes during the establishment of adapted neuroendocrine functions.

  13. Selective decrease in axonal nerve growth factor and insulin-like growth factor I immunoreactivity in axonopathies of unknown etiology.

    PubMed

    Fressinaud, Catherine; Jean, Isabelle; Dubas, Frédéric

    2003-05-01

    In an attempt to approach the mechanisms underlying axonopathies of unknown etiology, we have studied by immunocytochemistry the fate of several growth factors in eight of such cases that we had previously analyzed by morphometry and which were characterized by a decrease in neurofilaments and an increase in beta tubulin immunostaining. Here we establish that, contrary to beta tubulin, growth-associated protein43 (GAP-43) immunolabeling is not up-regulated in theses cases, correlating well with the failure of regeneration. Neurotrophin-3 (NT-3) and its receptor TrkC were not modified compared to controls (five cases). On the contrary, we observed in all cases a pronounced decrease in the number of fibers labeled for nerve growth factor (NGF) and insulin-like growth factor I (IGF-I), which were both approximately half of control values. This decrease could not be ascribed to the reduction in fiber density since it was also present in cases without fiber loss (isolated large fiber atrophy). The fact that only around 50% of fibers were stained, versus all fibers in controls, probably accounted for this decrease. It contrasted also with the normality of NGF and IGF-I immunolabeling in six cases of chronic inflammatory demyelinating neuropathy that were investigated in parallel. These results differ from those reported in experimental diabetic neuropathy, during which NT-3 is also decreased. A deficient supply of specific growth factors delivered by neuronal targets may be responsible for these neuropathies and their associated axonal cytoskeleton abnormalities.

  14. Role of various cytokines and growth factors in pubertal development.

    PubMed

    Casazza, Krista; Hanks, Lynae J; Alvarez, Jessica A

    2010-01-01

    Historical data suggest that body composition is intricately involved in pubertal development. Progression through puberty is dependent on the interaction between the growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis, reproductive and metabolic hormones as well as pro- and anti-inflammatory cytokines which induce alterations in feedback mechanisms and therefore mediate body composition and growth. Simultaneous increases in GH and IGF-1, and the concomitant changes in the hormonal milieu (i.e. reproductive hormones, testosterone and estrogen, and insulin)are the major contributors to anabolic effects seen throughout the pubertal transition, and are affected by various factors including (but not limited to) energy status and body composition. Orexigenic agents (i.e. ghrelin and leptin) also play a role at the level of the hypothalamus affecting not only energy intake, but also pubertal onset and progression. Effects of cytokines, many of which may be considered catabolic, extend beyond their traditionally viewed role involving the immune system, accompanying reproductive maturity further regulating aspects of energy and bone metabolism. As such, the signal(s) initiating the hypothalamic response that triggers puberty is likely reliant on a number of neural, metabolic and endocrine networks, all of which are at least partially influenced by pubertal growth factors, and act independently, antagonistically and/or synergistically to regulate anabolic pathways, therefore modifying body composition trajectory and growth during adolescence.

  15. Temperature affects insulin-like growth factor I and growth of juvenile southern flounder, Paralichthys lethostigma.

    PubMed

    Luckenbach, J Adam; Murashige, Ryan; Daniels, Harry V; Godwin, John; Borski, Russell J

    2007-01-01

    Temperature profoundly influences growth of heterothermic vertebrates. However, few studies have investigated the effects of temperature on growth and insulin-like growth factor I (IGF-I) in fishes. The aim of this study was to examine effects of temperature on growth and establish whether IGF-I may mediate growth at different temperatures in southern flounder, Paralichthys lethostigma. In two experiments, juvenile flounder were reared at 23 and 28 degrees C and growth was monitored for either 117 or 197 days. Growth was similar across treatments in both experiments until fish reached approximately 100 mm total length. Body size then diverged with fish at 23 degrees C ultimately growing 65-83% larger than those at 28 degrees C. Muscle IGF-I mRNA, plasma IGF-I, and hepatosomatic index (HSI) were significantly higher in flounder at 23 degrees C, whereas hepatic IGF-I mRNA abundance did not differ with treatment. Muscle IGF-I mRNA was correlated with HSI, while plasma IGF-I was correlated with body size, hepatic IGF-I mRNA, and HSI. These results demonstrate a strong effect of temperature on flounder growth and show that temperature-induced variation in growth is associated with differences in systemic IGF-I and local (i.e., muscle) IGF-I mRNA levels. The results also support the use of plasma IGF-I and HSI as indicators of flounder growth status.

  16. Marked stimulation of growth and motility of human keratinocytes by hepatocyte growth factor

    SciTech Connect

    Matsumoto, K.; Hashimoto, K.; Yoshikawa, K.; Nakamura, T. )

    1991-09-01

    Effect of hepatocyte growth factor (HGF) on normal human epidermal keratinocytes cultured under conditions of low Ca2+ (0.1 mM, growth-promoting condition) and physiological Ca2+ (1.8 mM, differentiation-promoting condition) was investigated. In low Ca2+, HGF markedly enhanced the migration of keratinocytes while it suppressed cell growth and DNA synthesis in a dose-dependent manner. In contrast, HGF enhanced the migration, cell growth, and DNA synthesis of keratinocytes cultured under conditions of physiological Ca2+. The maximal stimulation of DNA synthesis (2.4-fold stimulation) in physiological Ca2+ was seen at 2.5-5 ng/ml HGF and the stimulatory effect of HGF was suppressed by transforming growth factor-beta 1. Analysis of the HGF receptor using 125I-HGF as a ligand showed that human keratinocytes expressed a single class of specific, saturable receptor for HGF in both low and physiological Ca2+ conditions, exhibiting a Kd = 17.3 pM and approximately 690 binding sites/cell under physiological Ca2+. Thus, HGF is a potent factor which enhances growth and migration of normal human keratinocytes under conditions of physiological Ca2+. HGF may play an important role in epidermal tissue repair as it enhances both the migration and growth of keratinocytes.

  17. Assessing the Factors of Regional Growth Decline of Sugar Maple

    NASA Astrophysics Data System (ADS)

    Bishop, D. A.; Beier, C. M.; Pederson, N.; Lawrence, G. B.; Stella, J. C.; Sullivan, T. J.

    2014-12-01

    Sugar maple (Acer saccharum Marsh) is among the most ecologically, economically and culturally important trees in North America, but has experienced a decline disease across much of its range. We investigated the climatic and edaphic factors associated with A. saccharum growth in the Adirondack Mountains (USA) using a well-replicated tree-ring network incorporating a range of soil fertility (base cation availability). We found that nearly 3 in 4 A. saccharum trees exhibited declining growth rates during the last several decades, regardless of tree age or size. Although diameter growth was consistently higher on base-rich soils, the negative trends in growth were largely consistent across the soil chemistry gradient. Sensitivit