Enter Your Search:
Results 1-3 (3)
Go to page number:
Select a Filter Below
HSS Journal (2)
Journal of the American Chemical Society (1)
Hughes, Alex (2)
Cammisa, Frank P. (1)
Girardi, Federico (1)
Herr, Amy E. (1)
Hughes, Alex J. (1)
Kotwal, Suhel (1)
Lebl, Darren R. (1)
O’Leary, Patrick F. (1)
Pumberger, Matthias (1)
Tentori, Augusto M. (1)
Year of Publication
Bistable isoelectric point photoswitching in green fluorescent proteins observed by dynamic immunoprobed isoelectric focusing
Tentori, Augusto M.
Herr, Amy E.
Journal of the American Chemical Society
We describe a novel isoelectric point photoswitching phenomenon in both wild-type Aequorea victoria (av) GFP and the E222G mutant Aequorea coerulescens (ac) GFP. A combination of time-resolved microfluidic isoelectric focusing (IEF) and in situ antibody blotting IEF were employed to monitor dark (non-fluorescent) and bright (fluorescent) GFP populations. Through IEF, each population was observed to exhibit distinct isoelectric points (pI) and, thus, distinct formal electrostatic charges. Experimentally observed interconversion between the dark, higher pI and bright, lower pI GFP populations is tightly controlled by differential UV and blue light exposure. The stoichiometry and kinetics of charge transfer tied to this reversible photobleaching process are deduced. In concert with a reaction-transport model of bistable reversible charge and fluorescence photoswitching, the on-chip measurements of population interconversion rates suggest the potential for both rheostatic and discrete switch-like modulation of the electrostatic charge of GFPs depending on the illumination profile. We estimate that 3–4 formal charges distinguish the bright and dark populations of avGFP, compared to one charge for those of acGFP. Given the proposed role of E222 as a bridge between internal and exit hydrogen bond clusters within the GFP β-barrel, the difference in charge switching magnitude between the two mutants provides intriguing evidence for the proton wire hypothesis of proton transport within the GFP structure, and of proton exchange with the bulk solvent. Our facile dynamic and probed IEF assays should find widespread use in analytical screening and quantitative kinetic analysis of photoswitching and other charge switching processes in response to stimuli including light, temperature, or binding/cleavage events.
Degenerative Scoliosis: A Review
Degenerative lumbar scoliosis is a coronal deviation of the spine that is prevalent in the elderly population. Although the etiology is unclear, it is associated with progressive and asymmetric degeneration of the disc, facet joints, and other structural spinal elements typically leading to neural element compression. Clinical presentation varies and is frequently associated with axial back pain and neurogenic claudication. Indications for treatment include pain, neurogenic symptoms, and progressive cosmetic deformity. Non-operative treatment includes physical conditioning and exercise, pharmacological agents for pain control, and use of orthotics and invasive modalities like epidural and facet injections. Operative treatment should be contemplated after multi-factorial and multidisciplinary evaluation of the risks and the benefits. Options include decompression, instrumented stabilization with posterior or anterior fusion, correction of deformity, or a combination of these that are tailored to each patient. Incidence of perioperative complications is substantial and must be considered when deciding appropriate operative treatment. The primary goal of surgical treatment is to provide pain relief and to improve the quality of life with minimum risk of complications.
degenerative scoliosis; adult scoliosis; adult deformity; spinal stenosis; secondary scoliosis
Cervical Spondylotic Myelopathy: Pathophysiology, Clinical Presentation, and Treatment
Lebl, Darren R.
Cammisa, Frank P.
O’Leary, Patrick F.
Age-related changes in the spinal column result in a degenerative cascade known as spondylosis. Genetic, environmental, and occupational influences may play a role. These spondylotic changes may result in direct compressive and ischemic dysfunction of the spinal cord known as cervical spondylotic myelopathy (CSM). Both static and dynamic factors contribute to the pathogenesis. CSM may present as subclinical stenosis or may follow a more pernicious and progressive course. Most reports of the natural history of CSM involve periods of quiescent disease with intermittent episodes of neurologic decline. If conservative treatment is chosen for mild CSM, close clinical and radiographic follow-up should be undertaken in addition to precautions for trauma-related neurologic sequelae. Operative treatment remains the standard of care for moderate to severe CSM and is most effective in preventing the progression of disease. Anterior surgery is often beneficial in patients with stenotic disease limited to a few segments or in cases in which correction of a kyphotic deformity is desired. Posterior procedures allow decompression of multiple segments simultaneously provided that adequate posterior drift of the cord is attainable from areas of anterior compression. Distinct risks exist with both anterior and posterior surgery and should be considered in clinical decision-making.
cervical spine; spondylosis; myelopathy; natural history; operative treatment
Results 1-3 (3)
Go to page number:
Remove citation from clipboard
Add citation to clipboard
This will clear all selections from your clipboard. Do you wish proceed?
Clipboard is full! Please remove an item and try again.
PubMed Central Canada is a service of the
Canadian Institutes of Health Research
(CIHR) working in partnership with the National Research Council's
Canada Institute for Scientific and Technical Information
in cooperation with the
National Center for Biotechnology Information
U.S. National Library of Medicine
(NCBI/NLM). It includes content provided to the
PubMed Central International archive
by participating publishers.