China
Africa
Explore chapters and articles related to this topic
Manipulating the Intracellular Trafficking of Nucleic Acids
Published in Kenneth L. Brigham, Gene Therapy for Diseases of the Lung, 2020
Kathleen E. B Meyer, Lisa S. Uyechi, Francis C. Szoka
Microinjection, cell permeabilization, and isolated nuclei have been used to study the properties of nucleocytoplasmic transport. Microinjection allows the introduction of material into either the cytoplasmic or nuclear compartments in a living cell. This has been a powerful technique to study diffusion of macromolecules through the cytoplasm, the role of compartmentalization on expression of plasmid DNA, and the factors that regulate macromolecular transport into the nucleus. Digitonin has been effectively employed to permabilize the cell plasma membrane and introduce the substrate and supplemental cytosolic factors to replace proteins which escape while the membranes are compromised (developed by Adam and Gerace; see Ref. 115). This is a common method used to study the requirements for import of proteins into the nucleus. Isolated or reconstituted nuclei have also been used for studying nuclear transport in vitro and permit stringent control of the transport environment. More recently, genetic manipulation via deletion and complementation have been employed to determine the necessity of specific nuclear pore proteins for viability, growth, and transport.
Clinical Management of Men With Disorders of Sperm Motility
Published in Claude Gagnon, Controls of Sperm Motility, 2020
When motility is very poor or absent, then fertilization cannot take place because the sperm will not traverse the cumulous cell mass and the zona pellucida. In this situation, microinjection may be used to place the sperm adjacent to the egg membrane as it has been shown that sperm membrane fusion is not dependent on sperm motility.1 The theoretical danger with microinjection and to a lesser extent with all methods of artificial fertilization is that fertilization will be enabled that would not otherwise take place. There may be an increased rate of feotal abnormality because selection of healthy sperm that may be exerted by the female genital tract is bypassed. Such selection may occur as sperm traverse the cervical mucus and the coverings of the egg, and indeed it is well known that the zona pellucida is the species-specific barrier. The possibility of foetal abnormality would seem more likely if sperm are used from men who have poor sperm motility associated with multiple other abnormalities of spermatozoa (e.g., the OAT syndrome), and these new techniques may be most appropriate for those patients with defined isolated abnormalities of sperm motility such as Kartagener’s syndrome. It will be very important that the indications for such treatment are well defined in the scientific literature (e.g., a clear distinction between isolated motility defects such as Kartagener’s syndrome and the OAT syndrome) and also the results of treatment are monitored carefully and followup is undertaken to detect the congenital abnormality whether it is manifest at birth or at later years.
Neural Regulation of Coronary Blood Flow*
Published in Irving H. Zucker, Joseph P. Gilmore, Reflex Control of the Circulation, 2020
David D. Gutterman, Michael J. Brody, Melvin L. Marcus
Electrical stimulations were made in lateral hypothalamus before and after injecting the reversible neural blocking agent, lidocaine, into medullary lateral reticular formation. Lidocaine blocked the coronary vasoconstriction to hypothalamic stimulation, but did not affect the hindquarter constrictor response. This effect was not the result of nonspecific tissue damage by microinjection since recovery from the block was observed. A repeat injection of lidocaine also attenuated the coronary vasoconstriction. Thus the anatomic projections demonstrated from lateral hypothalamus to lateral reticular formation include fibers conveying coronary vasoconstrictor information.
Infravec2 guidelines for the design and operation of containment level 2 and 3 insectaries in Europe
Published in Pathogens and Global Health, 2023
Emilie Pondeville, Anna-Bella Failloux, Frederic Simard, Petr Volf, Andrea Crisanti, Roya Elaine Haghighat-Khah, Núria Busquets, Francesc Xavier Abad, Anthony J Wilson, Romeo Bellini, Sarah Marsh Arnaud, Alain Kohl, Eva Veronesi
Once anesthetized and placed on ice, mosquitoes can be manipulated on the bench and should be manipulated one by one to minimize the risk of escape. When using forceps or sharps such as the capillary needles used for microinjection systems, extra caution should be taken to avoid injuries (do not cross hands, do not recap needles, instrument placement, etc.). Breeding of infected mosquitoes might be required for specific experiments, for example, studies on vertical transmission or the impact of infection on arthropod fitness. In this case, larvae can be reared in small containers tightly covered by secured mesh and placed in larger boxes also covered by a secured net. For transport, if possible, close the larger box with a lid to avoid the risk of spillage of the water in the rearing container. Pupae should then be transferred into a small cup or flask inside primary adult containment for emergence. Gloveboxes as described above or larger meshed containment to house pans and cages can provide a layer of security for manipulation during rearing (e.g. opening primary container to place/remove egg laying paper).
Transgenic zebrafish larvae as a non-rodent alternative model to assess pro-inflammatory (neutrophil) responses to nanomaterials
Published in Nanotoxicology, 2022
Suzanne Gillies, Rachel Verdon, Vicki Stone, David M. Brown, Theodore Henry, Lang Tran, Carl Tucker, Adriano G. Rossi, Charles R. Tyler, Helinor J. Johnston
Whilst microinjection requires more specialized equipment and is more technically challenging than aqueous exposure, it allows inflammatory responses to be investigated at the injection site (as well as other locations) over time. Accordingly, we microinjected NMs into the otic vesicle of zebrafish larvae (the primordial ear of the larvae) and quantified the inflammatory response at the injection site. Here, we hypothesized that both Ag and ZnO NMs would stimulate the infiltration of neutrophils into the otic vesicle following microinjection. We selected the otic vesicle as a discrete target site for injection to induce a localized neutrophil response (Levraud et al. 2008; Harvie and Huttenlocher 2015; Buchan et al. 2020). Whilst other injection sites (e.g. swim bladder, caudal vein, hindbrain ventricle) have been used in the literature to investigate inflammatory responses to a range of stimuli, not all these sites can be used in non-protected life stages and the otic vesicle offers a suitable target site for assessing localized inflammatory responses as it is typically devoid of neutrophils and as there is evidence that they are recruited to this site in response to injury or infection (Levraud et al. 2008; Harvie and Huttenlocher 2015). To date, no published studies have investigated inflammatory responses to NMs following the aqueous exposure of injured zebrafish or following their microinjection into the otic vesicle.
Overexpression of NaV1.6 in the rostral ventrolateral medulla in rats mediates stress-induced hypertension via glutamate regulation
Published in Clinical and Experimental Hypertension, 2022
Lei Tong, Mengyu Xing, Jiaxiang Wu, Shuai Zhang, Dechang Chu, Haili Zhang, Fuxue Chen, Dongshu Du
For intra-nuclear administration in RVLM, each animal was placed in prone with the was mounted in a stereotaxic instrument (RWD, China) to ensure that the bregma and lambda were positioned on the same horizontal plane. RVLM microinjections were performed with a glass micropipette (tip diameter is 50–70 microns) by using the following coordinates: 3.7–4.0 mm caudal to lambdoid suture, 2 mm lateral to the midline, and 8.0 mm ventral to the surface of the dura (28). The amount of microinjection drug was glutamate receptor antagonist (Dizocilpine 20 pmoles & CNQX 150 pmoles) or GABA receptor antagonist (Bicuculline 5 pmoles) (MCE, China), and the volume was controlled at 1 μL/side. After each microinjection, the micropipette was left in place for approximately 3 minutes (23,29). The rats were anesthetized with urethane (1–1.5 g/kg iv) at supplemental doses as required (0.1–0.3 g/kg iv). The right femoral artery was cannulated using polyethylene catheters filled with heparinized saline (50 U/mL) (30). The distal end of the arterial cannula was attached to a pressure transducer to directly monitor the blood pressure (BP). Systolic blood pressure (SBP) and heart rate (HR) were simultaneously measured.