Localized periorbital edema as a clinical manifestation of sulfite sensitivity

Sulfite is commonly used in pharmaceuticals as a preservative. We report a unique clinical presentation of localized periorbital edema on the left eye after administration of sulfite-containing dexamethasone. The patient's sulfite sensitivity was confirmed by sulfite oral provocation test: periorbital edema on the same site developed after ingestion of 200 mg sodium bisulfite. She was non-atopic and did not complain of any respiratory symptoms. Allergy skin prick test with 100 mg/ml sodium bisulfite showed a negative result. She also has aspirin-sensitive urticaria which was confirmed by oral provocation test. In conclusion, sulfite can induce a localized periorbital edema, an uncommon manifestation in sensitive patients. Further investigations are needed to clarify the pathogenetic mechanisms.     

Studies on the structure and function of glycosylated and nonglycosylated neu differentiation factors. Similarities and differences of the alpha and beta isoforms

Comparative analyses of both glycosylated and nonglycosylated neu differentiation factor (NDF) isoforms revealed significant similarities and differences of their overall structures and functions. Biophysical analyses confirmed that all NDF isoforms are monomeric, but have an extended ellipsoidal shape in solution. All full-length NDFs are similar in secondary and tertiary structures and they contain no alpha-helix but are abundant in beta-strand structures. A small NDF fragment containing only the epidermal growth factor domain is also rich in beta-strand structures, but exhibits tertiary structure different from the long NDF forms. Monoclonal antibodies that selectively recognize epidermal growth factor domains of human NDF-alpha and -beta can specifically bind the respective NDF-alpha and -beta isoforms independent of NDF origins. Western blot analysis and quantitative binding assays further identify that an NDF preparation produced naturally from Rat1-EJ cells contains both alpha and beta isoforms in a 3 to 2 ratio. In receptor-binding competition experiments, human and rat NDF-beta isoforms have higher affinity than NDF-alpha isoforms. NDF-beta isoforms can dramatically enhance the stimulation of DNA synthesis for transfected NIH3T3 cells that overexpress HER-3 and HER-4 receptors, while NDF-alpha isoforms can only stimulate proliferation of HER-4-transfected cells with lower activity. Taken together, NDF-alpha and -beta isoforms share similar gross protein conformations but are biologically distinct.     

The motif V of plum pox potyvirus CI RNA helicase is involved in NTP hydrolysis and is essential for virus RNA replication

The plum pox potyvirus (PPV) protein CI is an RNA helicase whose function in the viral life cycle is still unknown. The CI protein contains seven conserved sequence motifs typical of RNA helicases of the superfamily SF2. We have introduced several individual point mutations into the region coding for motif V of the PPV CI protein and expressed these proteins in Escherichia coli as maltose binding protein fusions. Mutations that abolished RNA helicase activity also disturbed NTP hydrolysis. No mutations affected the RNA binding capacity of the CI protein. These mutations were also introduced in the PPV genome making use of a full-length cDNA clone. Mutant viruses carrying CI proteins with reduced RNA helicase activity replicated very poorly in protoplasts and were unable to infect whole plants without rapid pseudoreversion to wild-type. These results indicate that motif V is involved in the NTP hydrolysis step required for potyvirus RNA helicase activity, and that this activity plays an essential role in virus RNA replication inside the infected cell.     

Ideal thickness of Smith-Robinson graft for anterior cervical fusion. A cadaveric study with computed tomographic correlation

To establish the optimal thickness for Smith-Robinson anterior cervical fusion grafts, anterior C4-5 discectomy and fusions were performed on six fresh, frozen cadavers. Plain radiographs and computed tomographic scans then were employed to correlate graft placement with changes in disc space height, foraminal height, and foraminal areas after 3-, 5-, 7-, and 9-mm interbody fusions. The ideal graft thickness appeared to be directly related to the preoperative baseline disc height. For a preoperative disc height of 3.5-6.0 mm, an interbody graft of 2 mm above baseline thickness was most appropriate. A thicker graft was required when the baseline disc height was smaller (2.0 mm) and a thinner graft when the disc height was larger (7.4 mm). No significant correlation was noted between disc space distraction at C4-5 and disc height, foraminal height, or foraminal area at adjacent levels.     

Contemporary issues in rate-adaptive pacing

This review addresses a number of questions pertaining to contemporary rate-adaptive pacemakers that include the role of dual sensor systems, sensor blending and cross-checking, automaticity, nonrate-related sensor functions, prevention of arrhythmias, and several other areas of clinical importance.     

Electrocardiographic imaging: Noninvasive characterization of intramural myocardial activation from inverse-reconstructed epicardial potentials and electrograms

BACKGROUND: A recent study demonstrated the ability of electrocardiographic imaging (ECGI) to reconstruct, noninvasively, epicardial potentials, electrograms, and activation sequences (isochrones) generated by epicardial activation. The current study expands the earlier work to the three-dimensional myocardium and investigates the ability of ECGI to characterize intramural myocardial activation noninvasively and to relate it to the underlying fiber structure of the myocardium. This objective is motivated by the fact that cardiac excitation and arrhythmogenesis involve the three-dimensional ventricular wall and its anisotropic structure. METHODS AND RESULTS: Intramural activation was initiated by pacing a dog heart in a human torso tank. Body surface potentials (384 electrodes) were used to compute epicardial potentials noninvasively. Accuracy of reconstructed epicardial potentials was evaluated by direct comparison to measured ones (134 electrodes). Protocols included pacing from five intramural depths. Epicardial potentials showed characteristic patterns (1) early in activation, central negative region with two flanking maxima aligned with the orientation of fibers at the depth of pacing; (2) counterclockwise rotation of positive potentials with time for epicardial pacing, clockwise rotation for subendocardial pacing, and dual rotation for midmyocardial pacing; and (3) central positive region for endocardial pacing. Noninvasively reconstructed potentials closely approximated these patterns. Reconstructed epicardial electrograms and epicardial breakthrough times closely resembled measured ones, demonstrating progressively later epicardial activation with deeper pacing. CONCLUSIONS: ECGI can noninvasively estimate the depth of intramyocardial electrophysiological events and provides information on the spread of excitation in the three-dimensional anisotropic myocardium on a beat-by-beat basis.