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Results for “genetic modifiers”

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At least 397 records · Page 22Linked to original sources
PubMed1997

The effects of human macrophage inflammatory protein-1 alpha and its genetically modified variant, BB10010, on phagocyte function.

BB-10010 is a genetically modified form of human macrophage inflammatory protein-1 alpha (MIP-1 alpha) with a single amino acid substitution of Asp26 by alanine, which inhibits aggregation of the native molecule. BB-10010 has stem cell protective properties, and has entered clinical trials for this purpose. The aim of this study was to determine the effects of BB-10010 on human phagocyte function and compare them with the native molecule. MIP-1 alpha and BB-10010 had identical dose-response curves in assays of calcium mobilization; however, neutrophils were less sensitive than monocytes to either MIP-1 alpha form, suggesting differences in receptor expression. Neither MIP-1 alpha type directly stimulated phagocyte superoxide production, nor did it have any priming effect on agonist-induced superoxide production. Both MIP-1 alpha and BB-10010 enhanced monocyte migration; however, cells were more sensitive to the native molecule, with optimal effects seen at 1 ng/ml compared with 100 ng/ml BB-10010. Concomitant alteration of CD11b, CD18, and CD49d (VLA-alpha 4) cell adhesion molecule expression was not seen with either MIP-1 alpha type. With the exception of the difference in monocyte sensitivity in chemotaxis assays, BB-10010 reproduces the effects of the native molecule on phagocytes. BB-10010 does not have proinflammatory effects on neutrophil activation, and this bodes well for its clinical use.

Calcium↗
PubMed1995

Attachment, replication and thrombogenicity of genetically modified endothelial cells.

UNLABELLED: Endothelial cell seeding of prosthetic surfaces has been proposed as a technique to improve the patency of vascular grafts following arterial reconstruction. The introduction of specific recombinant DNA into seeded endothelial cells may enhance the anti-thrombogenic nature of the endothelial-blood interface with a consequent reduction in graft thrombosis. However, the successful use of genetically modified endothelial cells in the seeding process relies on the cells retaining normal function in terms of cellular replication, attachment and secretion of anti-thrombotic mediators. Successful genetic manipulation of human endothelial cells has been accomplished by viral and chemical methods. AIM: To study the functional characteristics of electrontransfected endothelial cells. METHODS AND RESULTS: Endothelial cells were electro-transfected with the test plasmid pTCF at a transfection efficiency of 10% utilising a single electric pulse with an electric field of 1000 volts/cm and a time constant of 12.8ms. The functional status of transfected endothelial cells was then compared with a control endothelial cell population. There were no significant differences in replication (p = 0.76), attachment (p = 0.43), basal (p = 0.89) or stimulated (p = 0.11) prostacyclin release between transfected cells as compared with control endothelial cells. CONCLUSIONS: Genetically modified cells are functionally normal, and may be used in endothelial cell seeding of prosthetic vascular surfaces.

Blood Vessel Prosthesis↗
PubMedDate not supplied

Grafts of fibroblasts genetically modified to secrete NGF, BDNF, NT-3, or basic FGF elicit differential responses in the adult spinal cord.

Neuronal and axonal responses to neurotrophic factors in the developing spinal cord have been relatively well characterized, but little is known about adult spinal responses to neurotrophic factors. We genetically modified primary rat fibroblasts to produce either nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), or basic fibroblast growth factor (bFGF), then grafted these neurotrophic factor-secreting cells into the central gray matter of the spinal cord in adult rats. Spinal cord lesions were not made prior to grafting. From 2 wk to 6 mo later, sensory neurites of dorsal root origin extensively penetrated NGF-, NT-3-, and bFGF-producing grafts, whereas BDNF-secreting grafts elicited no growth responses. Putative noradrenergic neurites also penetrated NGF-secreting cell grafts. Local motor and corticospinal motor axons did not penetrate any of the neurotrophic factor-secreting grafts. These results indicate that unlesioned or minimally lesioned adult spinal cord sensory and putative noradrenergic populations retain significant neurotrophic factor responsiveness, whereas motor neurites are comparatively resistant even to those neurotrophic factors to which they exhibit survival dependence during development. Grafts of genetically modified cells can be a useful tool for characterizing neurotrophic factor responsiveness in the adult spinal cord and designing strategies to promote axonal regeneration after injury.

Animals↗
PubMed2001

Treatment of Parkinson's Disease by Genetically Modified Immortalized Fibroblasts.

Primary rat fibroblast cells were immortalized by genetic modification of SV40 large T antigen (LT(Ag)) gene and called RFLT. This cell line was non-tumorigenic after grafting into nud-mouse and rat. The LT(Ag)gene stopped expression when the cells were transplanted in rat striatum, but it resumed the expression ability after the transplanted cells were recovered from striatum and cultured in vitro.TH gene and GCH gene were transfected into RFLT, respectively, and two types of transfected cells, RFLT-TH and RFLT-GCH, were obtained. In mixed culture with these two cell lines, DA was detected with HPLC-ECD. Implanting mixture of those cells into the striatum of PD rats significantly decreased their rotational asymmetry for up to 12 weeks. The expression of TH gene was proved by TH immunohistochemical staining in the sections of rat brain. The establishment of the genetically modified immortalized cells may play role in the gene therapy of PD.

Journal Article↗
PubMed1999

A recombinant measles virus expressing hepatitis B virus surface antigen induces humoral immune responses in genetically modified mice.

It has been shown previously that measles virus (MV) can be successfully used to express foreign proteins (M. Singh and M. A. Billeter, J. Gen. Virol. 80:101-106, 1998). To develop an inexpensive MV-based vaccine, we generated recombinant MVs that produce structural proteins of hepatitis B virus (HBV). A recombinant virus that expressed the HBV small surface antigen (HBsAg) was analyzed in terms of its replication characteristics, its genetic stability in cell culture, and its immunogenic potential in genetically modified mice. Although this virus showed a progression of replication slightly slower than that of the parental MV, it appeared to stably maintain the added genetic information; it uniformly expressed the appropriately glycosylated HBsAg after 10 serial passages. Genetically modified mice inoculated with this recombinant MV produced humoral immune responses against both HBsAg and MV proteins.

Animals↗
PubMed2005

Microchip capillary gel electrophoresis using programmed field strength gradients for the ultra-fast analysis of genetically modified organisms in soybeans.

We have developed a novel method for the ultra-fast analysis of genetically modified organisms (GMOs) in soybeans by microchip capillary gel electrophoresis (MCGE) using programmed field strength gradients (PFSG) in a conventional glass double-T microchip. Under the programmed electric field strength and 0.3% poly(ethylene oxide) sieving matrix, the GMO in soybeans was analyzed within only 11 s of the microchip. The MCGE-PFSG method was a program that changes the electric field strength during GMO analysis, and was also applied to the ultra-fast analysis of PCR products. Compared to MCGE using a conventional and constantly applied electric field, the MCGE-PFSG analysis generated faster results without the loss of resolving power and reproducibility for specific DNA fragments (100- and 250-bp DNA) of GM-soybeans. The MCGE-PFSG technique may prove to be a new tool in the GMO analysis due to its speed, simplicity, and high efficiency.

DNA, Plant↗
PubMed2005

Role of the "National Reference Centre for Genetically Modified Organisms (GMO) detection" in the official control of food and feed.

The National Reference Centre for Genetically Modified Organisms (GMO) detection was established in 2002 within the Istituto Zooprofilattico Sperimentale Lazio e Toscana, with the aim of providing scientific and technical support to the National Health System and to the Ministry of Health within the scope of the regulation of GMO use in food and feed.The recently adopted EU legislation on GMOs (Regulation CE no. 1829/2003 and no. 1830/2003) introduced more rigorous procedures for the authorisation, labelling and analytical control of food and feed consisting, containing or derived from GMOs. The National Reference Centre, besides its institutional tasks as one of the laboratories of the Italian National Health System, collects and analyses data and results of the national official control of GMOs; carries out scientific research aimed at developing, improving, validating and harmonising detection and quantification methods, in cooperation with other scientific institutions, the Community Reference Laboratory and within the European Network of GMOs laboratories (ENGL); collaborates with the Ministry of Health in the definition of control programmes and promotes educational and training initiatives. Objectives defined for 2004-2006, activities in progress and goals already achieved are presented.

European Union↗
PubMedDate not supplied

Safety assessments and public concern for genetically modified food products: the American view.

In the relatively short time since their commercial introduction in 1996, genetically modified (GM) crops have been rapidly adopted in the United States GM crops are regulated through a coordinated framework developed in 1992 and administered by three agencies-the US Department of Agriculture (USDA) that ensures the products are safe to grow, the Environmental Protection Agency (EPA) that ensures the products are safe for the environment, and the Food and Drug Administration (FDA) that ensures the products are safe to eat. Rigorous food and environmental safety assessments must be completed before GM crops can be commercialized. Fifty-one products have been reviewed by the FDA, including several varieties of corn, soybeans, canola, cotton, rice, sugar beets, potatoes, tomatoes, squash, papaya, and flax. Because FDA considers these crops "substantially equivalent" to their conventional counterparts, no special labeling is required for GM crops in the United States and they are managed as commodities with no segregation or identity preservation. GM crops have thus made their way through commodity distribution channels into thousands of ingredients used in processed foods. It has been estimated that 70% to 85% of processed foods on supermarket shelves in the United States today contain one or more ingredients potentially derived from GM crops. The food industry and retail industry have been monitoring the opinions of their consumers on the GM issue for the past several years. Numerous independent groups have also surveyed consumer concerns about GM foods. The results of these surveys are shared and discussed here.

Animals↗
PubMed2006

Conservation biology, genetically modified organisms, and the biosafety protocol.

Concerns have been raised regarding the potential adverse effects on biological diversity of the use of living modified organisms (LMOs, which are commonly known by similar terms such as genetically modified organisms). At the international level these concerns are addressed in part by an agreement known as the Cartagena Protocol on Biosafety and include potential toxic effects of insect-resistant crops on nontarget organisms and potential ecological effects of gene flow from modified crops, fish, microorganisms, or insects to wild species or counterparts. We reviewed the protocol's main provisions, including those dealing with risk assessment and risk management, decision making on imports, documentation accompanying shipments, and liability resulting from damages caused by LMOs. A medium-term program of work has been adopted by the parties, which includes the potential contribution of conservation biologists to delivering capacity building, developing risk assessment guidance, evaluating mechanisms of potential ecological damages from LMOs, and other issues. Conservation biologists and other experts have opportunities to influence the negotiations and implementation of the protocol by providing inputs at meetings, offering expertise to governments and organizations, and participating in or developing relevant projects and initiatives. Involvement of conservation biologists in the implementation and further development of the protocol would contribute to its effectiveness.

Animals↗
PubMed2004

Genetically modified mice: tools to decode the functions of connexins in the heart-new models for cardiovascular research.

It has long been known that gap junctions are required for the propagation of electrical impulse in the heart. A good deal later, the connexins (Cxs), which are probably exclusive components of the junctional channels that constitute the gap junctions, were identified. More recently, the in vivo functions of cardiac Cxs have been investigated by the analysis of genetically modified mice. These studies have confirmed that Cxs are involved in cardiac impulse conduction, and, unexpectedly, in heart morphogenesis. In addition, cardiac abnormalities described in mice genetically modified for Cx genes, and those observed in certain human cardiac diseases, have been proven to be similar.

Animals↗
PubMed2004

Brain transplantation of genetically modified bone marrow stromal cells corrects CNS pathology and cognitive function in MPS VII mice.

Current therapies for lysosomal storage diseases (LSDs), enzyme replacement therapy and bone marrow transplantation are effective for visceral organ pathology of LSD, but their effectiveness for brain involvement in LSDs is still a subject of controversy. As an alternative approach, we transplanted genetically modified bone marrow stromal (BMS) cells to lateral ventricle of newborn mucopolysaccharidosis VII (MPS VII) mice. MPS VII is one of LSDs and caused by deficiency of beta-glucuronidase (GUSB), resulting in accumulation of glycosaminoglycans (GAGs) in brain. At 2 weeks after transplantation, the GUSB enzyme-positive cells were identified in olfactory bulb, striatum and cerebral cortex, and the enzymatic activities in various brain areas increased. The GAGs contents in brain were reduced to near normal level at 4 weeks after transplantation. Although GUSB activity declined to homozygous level after 8 weeks, the reduction of GAGs persisted for 16 weeks. Microscopic examination indicated that the lysosomal distention was not found in treated animal brain. Cognitive function in MPS VII animals as evaluated by Morris Water Maze test in treated mice showed a marked improvement over nontreated animals. Brain transplantation of genetically modified BMS cells appears to be a promising approach to treat diffuse CNS involvement of LSDs.

Animals↗
PubMed2005

Genetically modified rice seeds accumulating GLP-1 analogue stimulate insulin secretion from a mouse pancreatic beta-cell line.

Glucagon-like peptide-1 (7-36) amide (GLP-1) is the most potent physiological insulinotropic hormone in humans. We produced large amounts of a GLP-1 analogue, [Ser8, Gln26, Asp34]-GLP-1, which is resistant to trypsin-digestion, as part of a chimeric rice seed storage protein, a 26 kDa globulin, in genetically modified rice seeds. Junction sites between GLP-1 analogue and globulin were replaced by tryptic cleavage sites. The highest level of GLP-1 analogue accumulation was approximately 20-50 microg per seed. We found that GLP-1 analogue derived from trypsin-digested genetically modified rice seeds stimulated insulin secretion from a mouse pancreatic beta-cell line, MIN6.

Animals↗
PubMed2005

Fine-tuning in Ca2+ homeostasis underlies progression of cardiomyopathy in myocytes derived from genetically modified embryonic stem cells.

Mutations of genes encoding contractile proteins are responsible for familial hypertrophic cardiomyopathies. Understanding the process of differentiation of cardiomyocytes carrying a mutated protein is a crucial step towards potential treatments of inherited cardiac disorders. Embryonic Stem (ES) cells which faithfully recapitulate in vitro the process of cardiac cell differentiation can be genetically modified to incorporate a mutation mimicking a cardiomyopathy. ES cell lines engineered to express a wild-type (MLC2vGFP) or a mutated form (R58QMLC2vGFP) of ventricular myosin light chain 2 (MLC2v) fused to GFP were differentiated into cardiomyocytes within embryoid bodies (EBs). Visualization of GFP combined with sarcomeric actinin immunofluorescence of EBs revealed that mutated MLC2v dramatically prevented myofibrillogenesis. Cardiomyocytes expressing wild-type MLC2v featured spontaneous Ca(2+) spiking, but not those harboring the mutation. Expression of cardiac transcription factors Mef2c, GATAs, myocardin and Nkx2.5 was not affected by cell expression of mutated MLC2v. A dramatic decrease in expression of mRNAs encoding alpha-actin, MLC2a and MLC2v was observed in R58QMLC2vGFP EBs. This event was attributed to a failure of Mef2c to translocate into the nucleus, a Ca(2+)-dependent process. Expression in mutated cells of a constitutively active Ca(2+)- and calmodulin-dependent kinase II or treating EBs with ionomycin fully restored translocation of Mef2c into the nucleus and expression of mRNAs encoding sarcomeric proteins partially rescued contractile activity of EBs. Alteration of Ca(2+) homeostasis in mutated cardioblasts affects the transcriptional program of cardiac cell differentiation leading to a defect in myofibrillogenesis, and, in turn, in contractility. Genetically modified ES cells provide a unique cell model to determine abnormalities in Ca(2+) homeostasis underlying progression of human cardiomyopathies.

Calcium↗
PubMed1994

Implantation of AtT-20 or genetically modified AtT-20/hENK cells in mouse spinal cord induced antinociception and opioid tolerance.

AtT-20 cells, which make and release beta-endorphin, or AtT-20/hENK cells, an AtT-20 cell line transfected with the human proenkephalin gene and secreting enkephalin as well as presumably beta-endorphin, were implanted in mouse spinal subarachnoid space. Cell implants did not affect the basal response to thermal nociceptive stimuli. Administration of isoproterenol, believed to stimulate secretion from these cells, produced antinociception in groups receiving AtT-20 or AtT-20/hENK cell implants but not in control groups receiving no cells. The antinociceptive effect of isoproterenol was dose related and could be blocked by the opioid antagonist naloxone. Implantation of these cells offers a novel approach for the study of tolerance. Mice receiving AtT-20 cell implants developed tolerance to beta-endorphin and the mu-opioid agonist DAMGO, whereas mice receiving genetically modified AtT-20/hENK cell implants developed tolerance to the delta-opioid agonist DPDPE. Genetically modified AtT-20/hENK cell implants, but not AtT-20 cell implants, reduced the development of acute morphine tolerance in the host mice. This finding is consistent with the suggestion that enkephalin alters development of opioid tolerance. These results suggest that opioid-releasing cells implanted around mouse spinal cord can produce antinociception and may provide an alternative therapy for chronic intractable pain.

Animals↗
PubMed2003

Multiplex polymerase chain reaction/membrane hybridization assay for detection of genetically modified organisms.

To improve detection efficiency and result accuracy, four screening primer pairs, four identifying primer pairs, one common primer pair and corresponding probes were designed for the development of multiplex polymerase chain reaction/membrane hybridization assay (MPCR-MHA) for detection of the foreign genes insert in genetically modified organisms (GMOs). After detecting condition and parameter were optimized and determined, MPCR reactions were developed for amplifying several target genes simultaneously in one tube. Primers were labeled with biotin at the 5'-end; biotinylated MPCR products were detected by hybridization to the oligonucleotide probes immobilized on a membrane with subsequent colorimetric detection to confirm hybridization. The testing of screening primers can judge whether the sample contains GMOs, and that of identifying primers can further judge what kinds of trait genes are contained in the sample. We detected nine soybean samples, six maize samples, seven potato samples and two rice samples by the MPCR-MHA method; at the same time we also detected them with single PCR-MHA method. The results between two methods have good consistency.

DNA Primers↗
PubMed2002

[Medico-genetic evaluation of sugar sand, obtained from genetically-modified sugar beet line 77 (toxicologico-biochemical studies)].

The rats were fed with the Suger from the Genetically Modified Suger Beet line 77 (Monsanto Ko, USA) 3 g/rat/day for 3 months. Their blood, urea and liver were investigated to measure total protein and glucose levels, aminotransferase and alkaline phosphatase activities, pH, creatinine level as well as hepatic enzyme activity of the I and II phases of henobiotic metabolism and whole and non-sedimentated lysosomal enzyme activities and activity of antioxidant system.

Alkaline Phosphatase↗
PubMed2002

[Medical-biological evaluation of genetically-modified sugar beet line 77 (chemical composition and toxicologico-biochemical studies)].

The rats were fed with the Genetically Modified Sugar Beet line 77 (Monsanto Ko, USA) 10 g/rat/day for 1 month. Their blood, urea and liver were investigated to measure total protein and glucose levels, aminotransferase and alkaline phosphatase activities, pH, creatinine level as well as hepatic enzyme activity of the I and II phases of xenobiotic metabolism and whole and non-sedimentated lysosomal enzyme activities and activity of antioxidant system.

Alkaline Phosphatase↗
PubMed1993

Continuous systemic secretion of a lysosomal enzyme by genetically modified mouse skin fibroblasts.

Lysosomal enzymes secreted or externally supplied into the extracellular medium can be internalized by cells and targeted to lysosomes after binding to specific membrane receptors. This process allows for the replacement of the missing enzyme activity in deficient cells. Using a retroviral vector, we have introduced the human beta-glucuronidase cDNA into primary mouse skin fibroblasts. The genetically modified cells were then engrafted into neo-organs that had been previously implanted into the peritoneal cavity of syngeneic recipient mice. The hypervascularized structures, made of collagen and basic fibroblast growth factor-coated synthetic fibers embedded into extracellular matrix gel, allowed in vivo survival of engrafted fibroblasts that expressed the human beta-glucuronidase cDNA for at least 3 months. The human enzyme was detected in the liver, lung, and spleen of experimental animals, but became undetectable after removal of the neo-organ. This observation indicated that the human enzyme was secreted into the serum and then captured by distant organs. The use of genetically modified fibroblasts implanted into neo-organs may, therefore, represent a convenient approach to enzyme replacement therapy in lysosomal storage diseases.

3T3 Cells↗