Victims of major electrical trauma frequently suffer extensive skeletal muscle and nerve damage, which is postulated to be principally mediated by electroporation and/or thermally driven cell membrane permeabilization. We have investigated the efficacy oftwo blood-compatible chemical surfactants for sealing electroporated muscle membranes. In studies using cultured skeletal muscle cells, poloxamer 188 (P188; an 8. Membrane damage is often manifested clinically by release of intracellular contents into the intravascular space (5), one of the clinical hallmarks of major electrical trauma. Skeletal muscle and peripheral nerve necrosis appears to be the primary cause of the high amputation rates associated with electrical trauma. We have postulated that, in the majority of victims, cell membrane permeabilization is the most important pathophysiologic event leading to tissue death (4,6,7) and, therefore, effective therapy for victims of electric shock must reestablish cell membrane structural integrity.Because membranes form spontaneously when surfactants (amphiphiles) are mixed in an aqueous solvent at sufficient concentration, we hypothesized that it may be possible to seal damaged cell membranes by exposing them to adequate concentrations of a noncytotoxic nonionic surfactant, possibly by incorporation of the surfactant into the membrane defects. In a preliminary test of this concept, we found that an 8.4-kDa nonionic synthetic surfactant, poloxamer 188 (P188), which has been clinically accepted for human intravenous administration, effectively sealed electroporated membranes of cultured skeletal muscle cells when used in concentrations >0.5 mg/ml (8, 9). We also noted that sealing the membrane enhanced cell survival as measured by vital dye [i.e., carboxyfluorescein (CF) and trypan blue] assays. The ability of P188 to bind to damaged membranes has been suggested in previous studies (10, 11).The purposes of this investigation were to determine whether the observed membrane effects of P188 on isolated cells were relatively specific to its molecular properties by comparing P188 with a neutral polysaccharide known to adsorb on the lipid bilayer (12), to determine whether the P188 and neutral polysaccharide would also reach damaged cell membranes in situ via intravenous administration and seal them after electropermeabilization, and, most important, to determine whether membrane sealing could prevent tissue necrosis following electrical injury. MATERIALS AND METHODS
The observation and analysis of 46 lines of the infrared v 2 band of the H: molecular ion are described. The data include 16 new observations as well as the 30 previously publ~shed lines. The spectra are observed in absorption in a hydrogen discharge using tunable monochromatic sources, either a laser difference-frequency system or a diode laser. Two modulation techniques, either d~scharge amplitude modulation or Doppler velocity modulation, are used to increase the sensitivity. Ground state combination differences between the observed lines are in good agreement with ab lrzltio calculations, and scaled ah itlitio rotational term values are used to relate the different K-energy stacks. Pade-type expressions are found useful in representing the line frequencies, and 44 lines are fitted by 23 parameters with a standard deviation of 0.014 cm-I. The two lines omitted appear to be perturbed by a rovibrational interaction between the v, and v l states that should become more important for higher values of J.
The observation of the high-resolution absorption spectrum of the H2D+ molecular ion in the region 2010–2610 cm−1 in discharges through mixtures of H2 and D2 gases is reported. Two types of tunable monochromatic sources are employed, either a diode laser (in Ottawa) or a difference-frequency laser system (in Chicago), and the sensitivity is improved by using either discharge modulation or Doppler velocity modulation techniques. A total of 66 new lines of H2D+ have been measured and assigned, mostly on the basis of ground-state combination differences, to specific rotational transitions of the ν2 and ν3 bands. These data, as well as the two known microwave lines, are fitted by means of two theoretical models, either an effective Hamiltonian model including a Padé representation of a conventional A-reduced centrifugal Hamiltonian for each vibrational level together with Coriolis and higher rotational interactions between ν2 and ν3, or a supermatrix model in which the matrix of the untransformed Hamiltonian is set up in a large vibration-rotation basis and diagonalized directly. In the supermatrix model most of the vibrationally off-diagonal matrix elements are constrained to values derived from Carney’s ab initio calculations, while the ν1 parameters are fitted to the observed lines of Amano. Because of the large number of parameters required in the effective Hamiltonian, the less flexible supermatrix model was valuable as a check of the assignments. The results of these fits make it possible to assign seven of the nine lines reported by Shy, Farley, and Wing in 1981. The observed band origins, ν2=2205.87 cm−1 and ν3=2335.45 cm−1, as well as the rotational constants, are in good agreement with ab initio predictions. With the use of one calculated term value to relate the stacks of levels with even and odd values of K″a, a table of observed term values of the lower rotational levels of the ground state and the ν2 and ν3 states is constructed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.