Reduction and Fixation of Sacroiliac joint Dislocation by the Combined Use of S1 Pedicle Screws and an Iliac Rod
Kai-Uwe Lewandrowski, Donald L. Wise, Debra J. Trantolo, Michael J. Yaszemski, Augustus A. White in Advances in Spinal Fusion, 2003
Two types of vectors for gene therapy are currently under investigation: viral and nonviral vectors. Viral vectors comprise a number of viral agents that undergo a process known as homologous recombination before being used for gene therapy. Homologous recombination consists of the deletion of portions of the viral genome so to make the virus replication-deficient and ready to accommodate the therapeutic transgene [101]. The genetically modified virus subsequently binds to and enters the host cell, and transduction begins with the injected DNA being incorporated into the host cell genome or remaining extrachromosomal. In either case, the transduced target cell is able to synthesize and secrete the protein encoded by the transgene. A number of viral vectors are being investigated, including adenovirus, adeno-associated virus, retrovirus, and herpes simplex viruses, each offering theoretical advantages and disadvantages related to the virus life cycle [139]. Nonviral vectors include a heterogeneous group of substances and techniques represented by naked DNA injection, electroporation, biolistics or gene gun, liposomes, and polymer-DNA complexes [137].
Basic Microbiology
Philip A. Geis in Cosmetic Microbiology, 2020
Unlike eukaryotic cells, bacteria can transfer DNA sequences between individuals that are not of the same lineage. This can occur between members of the same species or between different species. The three main mechanisms that bacteria use to perform horizontal gene transfer are listed here. Transformation—DNA found within the extracellular environment of the bacteria is actively taken up into the bacteria and is used either in its native state, such as with plasmids, or incorporated into the genome, as with chromosomal DNA sequences. The utilization of these sequences can often confer drastic new phenotypes on the bacteria that harbor those sequences.Transduction—Viruses that are present, incorporated into the chromosome of a bacterium, exit the infected bacteria to infect new host cells. In the process, they remove small portions of the chromosome of the infected bacteria. In the new host, these sequences are integrated into the new host genome.Conjugation—As mentioned previously, bacteria that are able to conjugate by producing sex pili can transfer DNA sequences across the pili and lead to incorporation of new chromosomal sequences within the other mating bacteria.
Antibiotics: The Need for Innovation
Nathan Keighley in Miraculous Medicines and the Chemistry of Drug Design, 2020
Once drug resistance through chance mutation has arisen, other bacterial cells can acquire resistance through genetic transfer. Not only is the gene for resistance transferred to daughter cells as resistant bacteria divide, but also genes can be passed between bacterial cells. There are two main ways in which this can occur: conjugation and transduction. In conjugation, the genetic material is transferred directly between bacterial cells, through a connecting bridge of sex pili built between the two cells. Transduction involves small sections of genetic material, called plasmids, being transferred by means of bacterial viruses (bacteriophages) which may leave a resistant cell, then go on to infect a non-resistant cell with the relevant genetic material needed to acquire resistance; in by doing so, passing on the genetic information in the plasmid containing the instruction for resistance enzymes, such as β-lactamase.
Innovative therapies for neovascular age-related macular degeneration
Published in Expert Opinion on Pharmacotherapy, 2019
Hasenin Al-Khersan, Rehan M. Hussain, Thomas A. Ciulla, Pravin U. Dugel
Recently, the eye has become a target for investigational gene therapy due to the monogenic nature of many inherited retinal diseases (IRDs), its accessibility, tight blood-ocular barrier, the ability to non-invasively monitor for functional and anatomic outcomes, as well as its relative immune-privileged state. Gene therapy for nAMD offers the promise of long-term continuous expression of anti-VEGF-A protein with a single administration. Viral vectors are conduits for transferring desired genetic information to host cells. Vectors currently used in ocular gene therapy clinical trials include adeno-associated virus (AAV), small single-stranded DNA viruses of the parvovirus family, and lentivirus, RNA viruses of the retrovirus family. After successful transduction, the target cells transcribe and translate the viral genetic material into therapeutic protein, which then modulates the pathogenesis of the targeted disease process.
An update on gene therapy for lysosomal storage disorders
Published in Expert Opinion on Biological Therapy, 2019
Murtaza S. Nagree, Simone Scalia, William M. McKillop, Jeffrey A. Medin
Standard VSV-G-pseudotyped recombinant LV displays a wide tropism [30]. Thus, systemic LV injection with VSV-G-pseudotyped LV results in widespread transduction and minimal tissue specificity [30]. However, transgene expression can still be restricted by employing tissue-specific promoters [58]. Cell type-specific transduction can also be achieved by modifying the LV pseudotype [59]. Systemically delivered LV transduction efficiency is largely a function of the bolus size (amount and concentration during injection) of the vector and the site of injection. For example, injection into the hepatic portal vein should allow more selective transduction of the liver [60]. LV tends to not permeate well into parenchymal components of tissues, which may be due to preferential transduction of, or phagocytosis by, Kupffer or similar cells [61].
How to discover new antibiotic resistance genes?
Published in Expert Review of Molecular Diagnostics, 2019
Linda Hadjadj, Sophie Alexandra Baron, Seydina M. Diene, Jean-Marc Rolain
The highlighting of an ARG transfer by conjugation is a reference method and is still used today to identify new ARGs [17–19]. A donor strain resistant to a specific antibiotic can confer resistance to a receptor strain initially susceptible to this antibiotic, and resistant mutant are selected by using this antibiotic as selection marker. This AR transfer is possible via a plasmid carrying an ARG. This natural mechanism is the main mechanism responsible for the spread of antibiotic resistance [20]. Plasmid transfer can also be performed by transformation, if the plasmid is not conjugative. Transduction is a third method used to transfer bacterial DNA from a donor strain to a receptor strain via a bacteriophage. These mechanisms are currently used by bacteria to transfer DNA to other bacteria and have been reproduced in vitro to highlight the presence of a transferrable gene.
Related Knowledge Centers
- Bacteria
- Bacterial Conjugation
- DNA
- Genome
- Horizontal Gene Transfer
- Lytic Cycle
- Salmonella
- Virus
- Viral Vector
- Transformation