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101.
102.
Joseph A. H. Romaniuk Lynette Cegelski 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2015,370(1679)
The ability to characterize bacterial cell-wall composition and structure is
crucial to understanding the function of the bacterial cell wall, determining
drug modes of action and developing new-generation therapeutics. Solid-state NMR
has emerged as a powerful tool to quantify chemical composition and to map
cell-wall architecture in bacteria and plants, even in the context of
unperturbed intact whole cells. In this review, we discuss solid-state NMR
approaches to define peptidoglycan composition and to characterize the modes of
action of old and new antibiotics, focusing on examples in
Staphylococcus aureus. We provide perspectives regarding
the selected NMR strategies as we describe the exciting and still-developing
cell-wall and whole-cell NMR toolkit. We also discuss specific discoveries
regarding the modes of action of vancomycin analogues, including oritavancin,
and briefly address the reconsideration of the killing action of β-lactam
antibiotics. In such chemical genetics approaches, there is still much to be
learned from perturbations enacted by cell-wall assembly inhibitors, and
solid-state NMR approaches are poised to address questions of cell-wall
composition and assembly in S. aureus and other organisms. 相似文献
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Pattern of expiratory muscle activation during lower thoracic spinal cord stimulation. 总被引:1,自引:0,他引:1
A F DiMarco J R Romaniuk K E Kowalski G Supinski 《Journal of applied physiology》1999,86(6):1881-1889
Large positive airway pressures (Paws) can be generated by lower thoracic spinal cord stimulation (SCS), which may be a useful method of restoring cough in spinal cord-injured patients. Optimal electrode placement, however, requires an assessment of the pattern of current spread during SCS. Studies were performed in anesthetized dogs to assess the pattern of expiratory muscle recruitment during SCS applied at different spinal cord levels. A multicontact stimulating electrode was positioned over the surface of the lower thoracic and upper lumbar spinal cord. Recording electromyographic electrodes were placed at several locations in the abdominal and internal intercostal muscles. SCS was applied at each lead, in separate trials, with single shocks of 0.2-ms duration. The intensity of stimulation was adjusted to determine the threshold for development of the compound action potential at each electrode lead. The values of current threshold for activation of each muscle formed parabolas with minimum values at specific spinal root levels. The slopes of the parabolas were relatively steep, indicating that the threshold for muscle activation increases rapidly at more cephalad and caudal sites. These results were compared with the effectiveness of SCS (50 Hz; train duration, 1-2 s) at different spinal cord levels to produce changes in Paw. Stimulation at the T9 and T10 spinal cord level resulted in the largest positive Paws with a single lead. At these sites, threshold values for activation of the internal intercostal (7-11th interspaces) upper portions of external oblique, rectus abdominis, and transversus abdominis were near their minimum. Threshold values for activation of the caudal portions of the abdominal muscles were high (>50 mA). Our results indicate that 1) activation of the more cephalad portions of the abdominal muscles is more important than activation of caudal regions in the generation of positive Paws and 2) it is not possible to achieve complete activation of the expiratory muscles with a single electrode lead by using modest current levels. In support of this latter conclusion, a two-electrode lead system results in more uniform expiratory muscle activation and significantly greater changes in Paw. 相似文献
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V G Koveshnikov Ia I Fedoniuk V Z Sikora A N Romaniuk 《Arkhiv anatomii, gistologii i émbriologii》1989,97(7):47-53
The epiphyseal cartilage and diaphysis of the tibia have been studied at dehydration and burn trauma. Dehydration produces certain disturbances in growth and formation of the bone, and burn trauma--development of dystrophic changes. 相似文献
107.
V.B. Fernández Vallone M.A. Romaniuk H. Choi V. Labovsky J. Otaegui N.A. Chasseing 《Differentiation; research in biological diversity》2013,85(1-2):1-10
The considerable therapeutic potential of human multipotent mesenchymal stromal cells or mesenchymal stem cells (MSCs) has generated increasing interest in a wide variety of biomedical disciplines. Nevertheless, researchers report studies on MSCs using different methods of isolation and expansion, as well as different approaches to characterize them; therefore, it is increasingly difficult to compare and contrast study outcomes. To begin to address this issue, the Mesenchymal and Tissue Stem Cell Committee of the International Society for Cellular Therapy proposed minimal criteria to define human MSCs. First, MSCs must be plastic-adherent when maintained in standard culture conditions (α minimal essential medium plus 20% fetal bovine serum). Second, MSCs must express CD105, CD73 and CD90, and MSCs must lack expression of CD45, CD34, CD14 or CD11b, CD79α or CD19 and HLA-DR surface molecules. Third, MSCs must differentiate into osteoblasts, adipocytes and chondroblasts in vitro. MSCs are isolated from many adult tissues, in particular from bone marrow and adipose tissue. Along with their capacity to differentiate and transdifferentiate into cells of different lineages, these cells have also generated great interest for their ability to display immunomodulatory capacities. Indeed, a major breakthrough was the finding that MSCs are able to induce peripheral tolerance, suggesting that they may be used as therapeutic tools in immune-mediated disorders. Although no significant adverse events have been reported in clinical trials to date, all interventional therapies have some inherent risks. Potential risks for undesirable events, such as tumor development, that might occur while using these stem cells for therapy must be taken into account and contrasted against the potential benefits to patients. 相似文献
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Reflex control of diaphragm activation by thoracic afferents 总被引:1,自引:0,他引:1