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Factor Production (factor + production)
Kinds of Factor Production Selected AbstractsTotal Synthesis of (-)-Scabronine G, an Inducer of Neurotrophic Factor Production.CHEMINFORM, Issue 6 2006Stephen P. Waters No abstract is available for this article. [source] Thalidomide for the treatment of multiple myelomaCONGENITAL ANOMALIES, Issue 3 2004Yutaka Hattori ABSTRACT Although thalidomide was withdrawn in the 1960s after its teratogenic property was recognized, it was subsequently found that this drug possesses immunomodulatory and anti-inflammatory effects. Recent studies have also demonstrated that thalidomide has antineoplastic activity via an antiangiogenic mechanism. Observations in the late 1990s that the microenvironment in the bone marrow plays a role in tumor progression in multiple myeloma provided an impetus to use thalidomide for the treatment of this disease. It is known that thalidomide monotherapy is effective in one-third of refractory cases, and in combination with glucocorticoids and/or antineoplastic drugs, thalidomide provides a response rate of more than 50%. Thus, thalidomide therapy is considered a standard approach for the treatment of relapsed and refractory myeloma. The exact mechanism of the antimyeloma effect of thalidomide is not yet clearly understood. Anti-angiogenic effects, direct activity in tumor cells such as the induction of apoptosis or G1 arrest of the cell cycle, the inhibition of growth factor production, the regulation of interactions between tumor and stromal cells, and the modulation of tumor immunity have been considered as possible mechanisms. In addition to its teratogenicity, the adverse effects of thalidomide have been general symptoms such as somnolence and headache, peripheral neuropathy, constipation, skin rash, and other symptoms. Although these adverse effects are generally reversible and mild, grade 3 and 4 toxicities such as peripheral neuropathy, deep venous thrombosis, neutropenia, and toxic dermal necrosis have occasionally been reported. The application of thalidomide therapy in patients with multiple myeloma is being broadened to include not only cases of refractory myeloma, but also previously untreated cases, as well as for maintenance therapy after hematopoietic stem cell transplantation and for the treatment of other hematological diseases. The safe use of this drug will depend on the establishment of diagnostic and treatment guidelines. In addition, the establishment of a nation-wide regulation system is urgently needed in Japan. [source] The Pseudomonas aeruginosa quinolone signal (PQS) has an iron-chelating activityENVIRONMENTAL MICROBIOLOGY, Issue 8 2006Florian Bredenbruch Summary Virulence factor production and the development of biofilms in Pseudomonas aeruginosa have been shown to be regulated by two hierarchically organized quorum-sensing systems activated by two types of small acyl-homoserine lactone signal molecules. Recently, a third type of bacterial signal molecule, the Pseudomonas quinolone signal (PQS), has been identified, which positively regulates a subset of genes dependent on the quorum-sensing systems. However, the molecular mechanism underlying PQS signalling has remained poorly understood. In this study the global transcriptional profile of P. aeruginosa in response to PQS revealed a marked upregulation of genes belonging to the tightly interdependent functional groups of the iron acquisition and the oxidative stress response. Remarkably, most of the differentially regulated genes, as well as the induction of rhlR, could be traced back to an iron-chelating effect of PQS. Our results amount to the elucidation of how PQS affects P. aeruginosa and have important implications for the understanding of the complex regulatory circuits involved in P. aeruginosa gene regulation. [source] Role of exercise-induced brain-derived neurotrophic factor production in the regulation of energy homeostasis in mammalsEXPERIMENTAL PHYSIOLOGY, Issue 12 2009Bente K. Pedersen Brain-derived neurotrophic factor (BDNF) has been shown to regulate neuronal development and plasticity and plays a role in learning and memory. Moreover, it is well established that BDNF plays a role in the hypothalamic pathway that controls body weight and energy homeostasis. Recent evidence identifies BDNF as a player not only in central metabolism, but also in regulating energy metabolism in peripheral organs. Low levels of BDNF are found in patients with neurodegenerative diseases, including Alzheimer's disease and major depression. In addition, BDNF levels are low in obesity and independently so in patients with type 2 diabetes. Brain-derived neurotrophic factor is expressed in non-neurogenic tissues, including skeletal muscle, and exercise increases BDNF levels not only in the brain and in plasma, but in skeletal muscle as well. Brain-derived neurotrophic factor mRNA and protein expression was increased in muscle cells that were electrically stimulated, and BDNF increased phosphorylation of AMP-activated protein kinase (AMPK) and acetyl coenzyme A carboxylase-beta (ACC,) and enhanced fatty oxidation both in vitro and ex vivo. These data identify BDNF as a contraction-inducible protein in skeletal muscle that is capable of enhancing lipid oxidation in skeletal muscle via activation of AMPK. Thus, BDNF appears to play a role both in neurobiology and in central as well as peripheral metabolism. The finding of low BDNF levels both in neurodegenerative diseases and in type 2 diabetes may explain the clustering of these diseases. Brain-derived neurotrophic factor is likely to mediate some of the beneficial effects of exercise with regard to protection against dementia and type 2 diabetes. [source] Decreased virulence of a strain of Pseudomonas aeruginosa O12 overexpressing a chromosomal type 1 ,-lactamase could be due to reduced expression of cell-to-cell signaling dependent virulence factorsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2000Françoise Ramisse Abstract Pseudomonas aeruginosa produces a large variety of virulence factors and is characterized by its capacity to rapidly develop resistance when exposed to antibiotics. In order to evaluate a possible correlation between acquired resistance to antibiotics and virulence, we examined the virulence of four isogenic variants of P. aeruginosa O12 that differ in their resistance phenotypes to various ,-lactam antibiotics in a mouse model of acute pneumonia. Strains overproducing a chromosomal type 1 ,-lactamase were less virulent in both immunocompetent and immunosuppressed animals. Whereas the production of the exopolysaccharide alginate was similar between the four strains, extracellular virulence factors (elastase, rhamnolipid) that are controlled by the cell-to-cell signaling system circuit were detected in reduced amounts in the supernatant of the two isolates overproducing type 1 ,-lactamase. These results suggest that strains overexpressing the chromosomal type 1 ,-lactamase could be less virulent because of a reduction of cell-to-cell signaling dependent virulence factor production. [source] Pyrazolo,pyrimidine-derived c-Src inhibitor reduces angiogenesis and survival of squamous carcinoma cells by suppressing vascular endothelial growth factor production and signalingINTERNATIONAL JOURNAL OF CANCER, Issue 5 2007Sandra Donnini Abstract Src tyrosine kinase family cooperates with activated growth factor receptors to regulate growth, invasion and metastasis. The authors examined the influence of a novel c-Src inhibitor, 1l, derived from 4-amino-substituted-pyrazolo,pyrimidines, on tumor angiogenesis and on the angiogenic output of squamous carcinoma cells, A431 and SCC-4. The effect of 1l was assessed on growth and microvessel density in A431 tumors and its effect compared with the established c-Src inhibitor PP-1. The effects of c-Src inhibition were investigated on vascular endothelial growth factor (VEGF) expression and activity in tumor cells grown in vivo and in vitro, as well as on VEGF mediated signaling and on endothelial cell functions. Nanomolar concentrations of 1l decreased tumor volume promoted by A431 implanted in nude mice, without affecting in vitro cell tumor survival. This effect was related to 1l inhibition of VEGF production, and secondary to an effect on tumor microvessel density. The rabbit cornea assay confirmed that 1l markedly decreased neovessel growth induced by VEGF. In cultured endothelial cells, 1l inhibited the VEGF-induced phosphorylation on tyr416 of c-Src, resulting in a reduced cell proliferation and invasion. Consistently, 1l dowregulated endothelial nitric oxide synthase, MAPK-extracellular receptor kinase 1,2 (ERK1-2) activity and matrix metalloproteinases (MMP-2/MMP-9), while the tissue inhibitors of metalloproteinases (TIMP2/TIMP-1) were upregulated. These results demonstrate that nM concentrations of c-Src kinase inhibitors (1l and PP-1), by reducing the production of VEGF released by tumor cell and its endothelial cell responses, have a highly selective antiangiogenesis effect, which might be useful in combination therapies. © 2006 Wiley-Liss, Inc. [source] Endogenous glucocorticoids decrease skeletal angiogenesis, vascularity, hydration, and strength in aged miceAGING CELL, Issue 2 2010Robert S. Weinstein Summary Aging or glucocorticoid excess decrease bone strength more than bone mass in humans and mice, but an explanation for this mismatch remains elusive. We report that aging in C57BL/6 mice was associated with an increase in adrenal production of glucocorticoids as well as bone expression of 11,-hydroxysteroid dehydrogenase (11,-HSD) type 1, the enzyme that activates glucocorticoids. Aging also decreased the volume of the bone vasculature and solute transport from the peripheral circulation to the lacunar-canalicular system. The same changes were reproduced by pharmacologic hyperglucocorticoidism. Furthermore, mice in which osteoblasts and osteocytes were shielded from glucocorticoids via cell-specific transgenic expression of 11,-HSD type 2, the enzyme that inactivates glucocorticoids, were protected from the adverse effects of aging on osteoblast and osteocyte apoptosis, bone formation rate and microarchitecture, crystallinity, vasculature volume, interstitial fluid, and strength. In addition, glucocorticoids suppressed angiogenesis in fetal metatarsals and hypoxia inducible factor-1, transcription and vascular endothelial growth factor production in osteoblasts and osteocytes. These results, together with the evidence that dehydration of bone decreases strength, reveal that endogenous glucocorticoids increase skeletal fragility in old age as a result of cell autonomous effects on osteoblasts and osteocytes leading to interconnected decrements in bone angiogenesis, vasculature volume, and osteocyte-lacunar-canalicular fluid. [source] Human bone marrow stromal cell cultures conditioned by traumatic brain tissue extracts: Growth factor productionJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2002Xiaoguang Chen Abstract Treatment of traumatic brain injury (TBI) with bone marrow stromal cells (MSCs) improves functional outcome in the rat. However, the specific mechanisms by which introduced MSCs provide benefit remain to be elucidated. Currently, the ability of therapeutically transplanted MSCs to replace injured parenchymal CNS tissue appears limited at best. Tissue replacement, however, is not the only possible compensatory avenue in cell transplantation therapy. Various growth factors have been shown to mediate the repair and replacement of damaged tissue, so trophic support provided by transplanted MSCs may play a role in the treatment of damaged tissue. We therefore investigated the temporal profile of various growth factors, brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and hepatocyte growth factor (HGF), within cultures of human MSCs (hMSCs) conditioned with cerebral tissue extract from TBI. hMSCs were cultured with TBI extracts of rat brain in vitro and quantitative sandwich enzyme-linked immunosorbent assays (ELISAs) were performed. TBI-conditioned hMSCs cultures demonstrated a time-dependent increase of BDNF, NGF, VEGF, and HGF, indicating a responsive production of these growth factors by the hMSCs. The ELISA data suggest that transplanted hMSCs may provide therapeutic benefit via a responsive secretion of an array of growth factors that can foster neuroprotection and angiogenesis. © 2002 Wiley-Liss, Inc. [source] Differential platelet-activating factor synthesis by monocytes and polymorphonuclear leukocytes from subjects with localized aggressive periodontitisJOURNAL OF PERIODONTAL RESEARCH, Issue 3 2007C. R. Shin Background and Objective:, Platelet-activating factor is elevated in localized aggressive periodontitis. We previously demonstrated that the elevated level of platelet-activating factor in localized aggressive periodontitis is at least partially attributable to low levels of platelet-activating factor acetylhydrolase, the enzyme that catabolizes platelet-activating factor. The objective of this study was to determine if platelet-activating factor synthesis was also elevated in localized aggressive periodontitis. To test this, platelet-activating factor synthesis was quantified in the monocytes and polymorphonuclear neutrophils of periodontally healthy patients and of subjects with localized aggressive periodontitis. Material and Methods:, Cells were labeled with [3H]acetate and treated with vehicle or stimulated with calcium ionophore A23187. Platelet-activating factor was extracted and quantified by scintillation counting. Results:, For both subject groups, resting monocytes and polymorphonuclear neutrophils produced platelet-activating factor, and calcium ionophore A23187 stimulated platelet-activating factor production in both cell types. However, calcium ionophore A23187-activated monocytes from subjects with localized aggressive periodontitis produced less platelet-activating factor than did activated periodontally healthy monocytes (p < 0.0001), suggesting an aberrant calcium ionophore A23187 response in monocytes from subjects with localized aggressive periodontitis. Indeed, when the data were expressed as fold induction of platelet-activating factor synthesis in response to calcium ionophore A23187, monocytes from subjects with localized aggressive periodontitis exhibited only a fourfold increase in platelet-activating factor synthesis, whereas calcium ionophore A23187-stimulated monocytes from periodontally healthy, chronic periodontitis and generalized aggressive periodontitis subjects produced ,,12 times more platelet-activating factor than did resting monocytes. In contrast, both resting and activated localized aggressive periodontitis polymorphonuclear neutrophils synthesized more platelet-activating factor than did periodontally healthy polymorphonuclear neutrophils. Conclusion:, These data suggest that high levels of platelet-activating factor in subjects with localized aggressive periodontitis result from both increased synthesis and reduced catabolism. While localized aggressive periodontitis polymorphonuclear neutrophils contribute to increased platelet-activating factor mass through synthesis, the contribution of monocytes is probably the result of reduced catabolism by platelet-activating factor acetylhydrolase. [source] Expression of CD73/ecto-5,-nucleotidase on human gingival fibroblasts and contribution to the inhibition of interleukin-1,-induced granulocyte-macrophage colony stimulating factor productionJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2004Eiji Nemoto Background and objectives:, CD73/5,-nucleotidase (5,-NT) is an ectoenzyme that participates in immune/inflammatory reactions. We examined the possible expression of CD73/5,-NT on human gingival fibroblasts (hGF), which are important to the immune/inflammatory system in periodontal tissue. Methods and results:, We demonstrated that CD73/5,-NT was expressed on hGF by flow cytometry. We found that pre-treatment of hGF with 5,-AMP induced marked inhibition of granulocyte-macrophage colony-stimulating factor (GM-CSF) production from hGF upon stimulation with interleukin-1, (IL-1,) by enzyme-linked immunosorbent assay (ELISA). A specific inhibitor of 5,-NT, adenosine 5,-[,,,-methylene] diphosphate blocked the inhibition of GM-CSF production, suggesting that adenosine converted from 5,-AMP acts on the inhibitory effects. The GM-CSF inhibition suggested that A3 receptor might be involved. The rank order of agonists was found to be (N6 -benzyl-5,- N -ethylcarboxamidoadenosine) A3 receptor agonist , (2-chloroadenosine) non-selective agonist > (CGS-21680) A2A receptor agonist > adenosine , (N6 -cyclohexyladenosine) A1 agonist. Further support for the main role of A3 receptor was the binding A3 antagonist [9-chloro-2-(2-furanyl)-5-([phenylacetyl]amino)[1,2,4]-triazolo[1,5- c]quinazdine] reversed the effect of adenosine, but no significant reverse was observed by A1 (1,3-dipropyl-8-cyclopentylxanthine), A2 [3,7-dimethyl-1-(2-propargyl)xanthine], A2A[8-(3-chlorostyryl)caffeine], and A2B (alloxazine) antagonists. The CD73/5,-NT expression was increased upon stimulation with gamma-interferon, but not other stimulants such as tumor necrosis factor-alpha, IL-4, lipopolysaccharide from Porphyromonas gingivalis and Escherichia coli, and fimbriae from P. gingivalis, and this increase was correlated with the enhanced GM-CSF inhibition by 5,-AMP but not adenosine. Conclusions:, These findings suggested that CD73/5,-NT on hGF exerts an anti-inflammatory effects in periodontal disease by conversion from 5,-AMP to adenosine. [source] Ethanol Alters Production and Secretion of Estrogen-Regulated Growth Factors That Control Prolactin-Secreting Tumors in the PituitaryALCOHOLISM, Issue 12 2007Dipak K. Sarkar Background:, Chronic administration of ethanol increases plasma prolactin levels and enhances estradiol's mitogenic action on the lactotropes of the pituitary gland. The present study was conducted to determine whether ethanol's lactotropic cell-proliferating action, like estradiol's, is associated with alteration in the production of 3 peptides that regulate cell growth: transforming growth factor beta 1 (TGF-,1), TGF-,3 and basic fibroblast growth factor (bFGF). Methods:, Using ovariectomized Fischer-344 female rats, we determined ethanol's and estradiol's actions on lactotropic cell proliferation and growth-regulatory peptide production and release in the pituitary gland during tumorigenesis. Results:, Ethanol increased basal and estradiol-enhanced mitosis of lactotropes in the pituitary glands of ovariectomized rats. The level of growth-inhibitory TGF-,1 was reduced in the pituitary following ethanol and/or estradiol treatment for 2 and 4 weeks. In contrast, ethanol and estradiol alone as well as together increased levels of growth-stimulatory TGF-,3 and bFGF in the pituitary at 2 and 4 weeks. In primary cultures of pituitary cells, both ethanol and estradiol reduced TGF-,1 release and increased TGF-,3 and bFGF release at 24 hours. Ethanol's effect on growth factor levels in the pituitary or growth factor release from the pituitary cells was less than that of estradiol. When ethanol and estradiol were applied together, their individual effects on these growth factors were amplified. Conclusions:, These results confirm estradiol's modulation of pituitary growth factor production and release, and provide evidence that ethanol, like estradiol, alters the production and secretion of growth-regulatory peptides controlling lactotropic cell proliferation. [source] Platelet function in sepsisJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 12 2004A. YAGUCHI Summary.,Background: Coagulation abnormalities and thrombocytopenia are common in severe sepsis, but sepsis-related alterations in platelet function are ill-defined. Objectives: The purpose of this study was to elucidate the effect of sepsis on platelet aggregation, adhesiveness, and growth factor release. Patients and methods: Agonist-induced platelet aggregation was measured in platelet-rich plasma separated from blood samples collected from 47 critically ill patients with sepsis of recent onset. Expression of platelet adhesion molecules was measured by flow cytometry and the release of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) was measured by ELISA in the supernatant of platelet aggregation. Results: Septic patients had consistently decreased platelet aggregation compared with controls, regardless of the platelet count, thrombin generation, or overt disseminated intravascular coagulation (DIC) status. The severity of sepsis correlated to the platelet aggregation defect. Adhesion molecules, receptor expression (CD42a, CD42b, CD36, CD29, PAR-1), and ,-granule secretion detected by P-selectin expression remained unchanged but the release of growth factors was differentially regulated with increased VEGF and unchanged PDGF after agonist activation even in uncomplicated sepsis. Conclusions: Sepsis decreases circulating platelets' hemostatic function, maintains adhesion molecule expression and secretion capability, and modulates growth factor production. These results suggest that sepsis alters the hemostatic function of the platelets and increases VEGF release in a thrombin-independent manner. [source] Co-regulation of Xanthomonas campestris virulence by quorum sensing and a novel two-component regulatory system RavS/RavRMOLECULAR MICROBIOLOGY, Issue 6 2009Ya-Wen He Summary Xanthomonas campestris pv. campestris (Xcc) is known to regulate virulence through a quorum-sensing mechanism. Detection of the quorum-sensing signal DSF by sensor RpfC leads to activation of the response regulator RpfG, which influences virulence by degrading cyclic-di-GMP and by subsequent increasing expression of the global regulator Clp. In this study, we show that mutation of a response regulator RavR containing the GGDEF,EAL domains decreases Xcc virulence factor production. The functionality of RavR is dependent on its EAL domain-associated cyclic-di-GMP phosphodiesterase activity. Deletion of a multidomain sensor gene ravS, which shares the same operon with ravR, results in similar phenotype changes as the ravR mutant. In addition, the sensor mutant phenotypes can be rescued by in trans expression of the response regulator, supporting the notion that RavS and RavR constitute a two-component regulatory system. Significantly, mutation of either the PAS domain or key residues of RavS implicated in sensing low-oxygen tension abrogates the sensor activity in virulence regulation. Moreover, similar to the DSF signalling system, RavS/RavR regulates virulence gene expression through the global regulator Clp. These results outline a co-regulation mechanism that allows Xcc to integrate population density and environmental cues to modulate virulence factor production and adaptation. [source] Identification of the central quorum sensing regulator of virulence in the enteric phytopathogen, Erwinia carotovora: the VirR repressorMOLECULAR MICROBIOLOGY, Issue 1 2006Tom Burr Summary In the Gram-negative phytopathogen, Erwinia carotovora ssp. atroseptica (Eca) virulence depends on the production of a N- (3-oxohexanoyl)- l -homoserine lactone (OHHL) quorum sensing (QS) signal. This work identifies the elusive ,missing link' between QS and virulence in Erwinia. We have identified and characterized a novel regulator of virulence, VirR, in Eca and show that a virR mutation completely restores virulence factor production to an Eca mutant unable to synthesize OHHL. This effect of the virR mutation translates to a restoration of virulence to wild-type levels and thus provides evidence that VirR acts to prevent the production of virulence factors at low cell density. We also show that, in Eca, transcription of virulence genes is controlled by OHHL and that this control is effected through the action of VirR. We also demonstrate that the VirR regulatory pathway is present and functional in both blackleg and soft rotting species of Erwinia. [source] Quorum sensing controls biofilm formation in Vibrio choleraeMOLECULAR MICROBIOLOGY, Issue 1 2003Brian K. Hammer Summary Multiple quorum-sensing circuits function in parallel to control virulence and biofilm formation in Vibrio cholerae. In contrast to other bacterial pathogens that induce virulence factor production and/or biofilm formation at high cell density in the presence of quorum-sensing autoinducers, V. cholerae represses these behaviours at high cell density. Consistent with this, we show here that V. cholerae strains ,locked' in the regulatory state mimicking low cell density are enhanced for biofilm production whereas mutants ,locked' in the regulatory state mimicking high cell density are incapable of producing biofilms. The quorum-sensing cascade we have identified in V. cholerae regulates the transcription of genes involved in exopolysaccharide production (EPS), and variants that produce EPS and form biofilms arise at high frequency from non-EPS, non-biofilm producing strains. Our data show that spontaneous mutation of the transcriptional regulator hapR is responsible for this effect. Several toxigenic strains of V. cholerae possess a naturally occurring frameshift mutation in hapR. Thus, the distinct environments occupied by this aquatic pathogen presumably include niches where cell-cell communication is crucial, as well as ones where loss of quorum sensing via hapR mutation confers a selective advantage. Bacterial biofilms could represent a complex habitat where such differentiation occurs. [source] Mechanisms of lymphatic metastasis in human colorectal adenocarcinoma,THE JOURNAL OF PATHOLOGY, Issue 5 2009Daniel Royston Abstract The invasion of lymphatic vessels by colorectal cancer (CRC) and its subsequent spread to draining lymph nodes is a key determinant of prognosis in this common and frequently fatal malignancy. Although tumoural lymphangiogenesis is assumed to contribute to this process, review of the current literature fails to support any notion of a simple correlation between lymphatic vessel density and CRC metastasis. Furthermore, attempts to correlate the expression of various lymphangiogenic growth factors, most notably VEGF-C and VEGF-D, with the lymphatic metastasis of CRC have provided contradictory results. Recent evidence from animal and human models of tumour metastasis suggests that complex functional and biochemical interactions between the microvasculature of tumours and other cell types within the tumour microenvironment may play a pivotal role in the behaviour of commonly metastasizing tumours. Indeed, previous insights into tumoural blood vessels have provided candidate markers of tumoural angiogenesis that are currently the subject of intense investigation as future therapeutic targets. In this review article we survey the current evidence relating lymphangiogenesis and lymphangiogenic growth factor production to metastasis by CRC, and attempt to provide some insight into the apparent discrepancies within the literature. In particular, we also discuss some new and provocative insights into the properties of tumoural lymphatics suggesting that they have specific expression profiles distinct from those of normal lymphatic vessels and that appear to promote metastasis. These findings raise the exciting prospect of future biomarkers of lymphatic metastasis and identify potential targets for new generation anti-tumour therapies. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Effects of Mitomycin-C on Normal Dermal Fibroblasts,THE LARYNGOSCOPE, Issue 4 2006Theodore Chen MD Abstract Objectives: To evaluate the effects of mitomycin-C on the growth and autocrine growth factor production of human dermal fibroblasts from the face. Study Design: In vitro study using normal adult dermal fibroblast cell lines in a serum-free model. Methods: Cell cultures were exposed to 4 mg/mL, 0.4 mg/mL, 0.04 mg/mL, 0.004 mg/mL, and 0.0004 mg/mL concentrations of mitomycin-C solution. Cell counts were performed, and the cell-free supernatants were collected at 0, 1, 3, and 5 days after the initial exposure. Population doubling times were calculated and supernatants were quantitatively assayed for basic fibroblast growth factor (bFGF) and transforming growth factor (TGF)-,1. Results: Continuous exposure to mitomycin-C caused fibroblast cell death by day 7 at all tested concentrations. A 4 minute exposure to mitomycin-C at 4 mg/mL caused rapid fibroblast cell death. A 4-minute exposure to mitomycin-C at either 0.4 mg/mL or 0.04 mg/mL resulted in decreased fibroblast proliferation. A 4 minute exposure to mitomycin-C at 0.4 mg/mL resulted in a marked increase in the production of both bFGF and TGF-,1. Conclusions: A clinically ideal concentration of mitomycin-C would slow fibroblast proliferation yet not cause cell death to allow for a wound healing response. Mitomycin-C 0.4 mg/mL for 4 minutes satisfies the above criteria in vitro. [source] Macrophage Depletion Suppresses Cardiac Allograft Vasculopathy in MiceAMERICAN JOURNAL OF TRANSPLANTATION, Issue 12 2007W. H. Kitchens Cardiac allograft vasculopathy (CAV) is a major source of late posttransplant mortality. Although numerous cell types are implicated in the pathogenesis of CAV, it is unclear which cells actually induce the vascular damage that results in intimal proliferation. Because macrophages are abundant in CAV lesions and are capable of producing growth factors implicated in neointimal proliferation, they are leading end-effector candidates. Macrophages were depleted in a murine heterotopic cardiac transplant system known to develop fulminant CAV lesions. C57BL/6 hearts were transplanted into (C57BL/6 × BALB/c)F1 recipients, which then received anti-macrophage therapy with intraperitoneal carrageenan or i.v. gadolinium. Intraperitoneal carrageenan treatment depleted macrophages by 30,80% with minimal effects upon T, B or NK cells as confirmed by flow cytometry and NK cytotoxicity assays. Carrageenan treatment led to a 70% reduction in the development of CAV, as compared to mock-treated controls (p = 0.01), which correlated with the degree of macrophage depletion. Inhibition of macrophage phagocytosis alone with gadolinium failed to prevent CAV. Macrophages may represent the end-effector cells in a final common pathway towards CAV independent of T-cell or B-cell alloreactivity and exert their injurious effects through mechanisms related to cytokine/growth factor production rather than phagocytosis. [source] Pulsed electromagnetic fields stimulation affects BMD and local factor production of rats with disuse osteoporosisBIOELECTROMAGNETICS, Issue 2 2010Wei-Wei Shen Abstract Pulsed electromagnetic fields (PEMF) have been used widely to treat nonunion fractures and related problems in bone healing, as a biological and physical method. With the use of Helmholtz coils and PEMF stimulators to generate uniform time-varying electromagnetic fields, the effects of extremely low frequency electromagnetic fields on bone mineral density (BMD) and local factor production in disuse osteoporosis (DOP) rats were investigated. Eighty 4-month-old female Sprague Dawley (SD) rats were randomly divided into intact (INT) group, DOP group, calcitonin-treated (CT) group, and PEMF stimulation group. The right hindlimbs of all the rats were immobilized by tibia-tail fixation except for those rats in the INT group. Rats in the CT group were injected with calcitonin (2,IU/kg, i.p., once a day) and rats in the PEMF group were irradiated with PEMF immediately postoperative. The BMD, serum transforming growth factor-beta 1 (TGF-,1), and interleukin-6 (IL-6) concentration of the proximal femur were measured 1, 2, 4, and 8 weeks after treatment. Compared with the CT and DOP groups, the BMD and serum TGF-,1 concentration in the PEMF group increased significantly after 8 weeks. The IL-6 concentration in the DOP group was elevated significantly after operation. The PEMF group showed significantly lower IL-6 level than the DOP group. The results found demonstrate that PEMF stimulation can efficiently suppress bone mass loss. We, therefore, conclude that PEMF may affect bone remodeling process through promoting TGF-,1 secretion and inhibiting IL-6 expression. Bioelectromagnetics 31:113,119, 2010. © 2009 Wiley-Liss, Inc. [source] JTE-607, a multiple cytokine production inhibitor, induces apoptosis accompanied by an increase in p21waf1/cip1 in acute myelogenous leukemia cellsCANCER SCIENCE, Issue 3 2010Nobuyuki Tajima (Cancer Sci 2010; 101: 774,781) Proinflammatory cytokines and growth factors have been thought to play crucial roles in the pathology of acute myelogenous leukemia (AML) by supporting the proliferation and survival of AML cells in an autocrine and paracrine manner, although further elucidation is required. JTE-607 was originally identified as a multiple cytokine inhibitor that suppresses production of proinflammatory cytokines from lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells. Herein, we report that JTE-607 exhibits inhibitory activity on the growth of AML cell lines accompanying reduction of the proinflammatory cytokine and growth factor production. In in vitro studies, JTE-607 suppressed expression and production of cytokines, which are spontaneously up-regulated in AML cell lines. JTE-607 also abrogated proliferation of AML cells in a concentration range in which colony formation of normal bone marrow cells was not affected. The growth inhibition by JTE-607 was characterized by induction of cell-cycle arrest at the S-phase and apoptosis, accompanied by a decrease in c-Myc and increase in p21waf1/cip1. In a leukemia model engrafted with U-937 cells, JTE-607 significantly prolonged survival in mice and reduced human cytokine mRNA levels in the bone marrow. These results suggest the usefulness of JTE-607 in therapeutic applications for patients with hypercytokinemia and aggressive AML cell proliferation. [source] Altering the Substrate Specificity of RhlI by Directed EvolutionCHEMBIOCHEM, Issue 3 2009Pavan Kumar Reddy Kambam Abstract Reducing virulence: RhlI catalyzes the synthesis of N -butanoyl homoserine lactone (BHL), with a minor product N -hexanoyl homoserine lactone (HHL). By using directed evolution and a genetic screen, RhlI has been engineered for enhanced production of both BHL and HHL at a similar level. Quorum sensing regulates biofilm formation and virulence factor production in the human opportunistic pathogen Pseudomonas aeruginosa. We used directed evolution to engineer RhlI, an enzyme in the RhlI,RhlR quorum-sensing system of P. aeruginosa, to alter its substrate specificity and gain insight into the molecular mechanisms of quorum sensing. By using a genetic screen, we identified a mutant with improved production of RhlI's two signaling molecules, N -butanoyl- and N -hexanoyl-homoserine lactone (BHL and HHL). In particular, production of BHL has been enhanced by more than two-fold, and the synthesis of HHL has been improved from an undetectable level to a level similar to BHL; this change indicates a significant change in substrate specificity. No significant change in the gene expression level was observed. Sequence alignments suggest that the mutations are most likely to facilitate interactions between the enzyme and the two acylated ACP substrates. This work also demonstrates that the genetic screen/selection should be useful in engineering additional quorum-sensing components. [source] | ||||||||||||||||