Purpose In cases of digital nerve injury in which nerve ends cannot be approximated without tension, autologous nerve grafts represent the most commonly used method for reconstruction. Recently, ...interest in synthetic nerve guides as an alternative to grafting has increased. Although several basic science studies have shown promise for collagen tubes, clinical studies of their success in humans are limited. The purpose of this study was to review our early clinical experience with collagen nerve tubes. Methods The authors identified and followed all cases involving digital nerve repair at our institution over a 2-year period. Twelve patients had repair of a digital nerve with a collagen nerve tube during the study period. Two patients were lost to follow-up, and 1 patient had amputation of the grafted finger secondary to complications of other injuries. The primary outcome data points for the remaining 9 patients were the static 2-point discrimination (2PD), Semmes-Weinstein monofilament testing, and a Quick Disabilities of the Arm, Shoulder, and Hand (DASH) outcome survey at final follow-up. Results Nine patients had follow-up of at least 1 year, with an average follow-up time of 15 months (range 12–22 months). There were no intraoperative or postoperative complications related to the nerve tubes. Using modified American Society for Surgery of the Hand guidelines, 2PD results were good or excellent in 8 out of 9 of patients. Semmes-Weinstein testing results were full in 5 patients, diminished light touch in 2, diminished protective sensation in 1, and loss of protective sensation in 1. Average Quick DASH scores for the group were 10.86 overall, 4.86 for the work module, and 23.21 for the sports/performing arts module. Conclusions Although the patients in this study are still within the early follow-up period, our initial results compare favorably with those reported in the existing literature for various types of nerve repair and reconstruction, suggesting that collagen nerve tubes might offer a clinically effective option for restoration of sensory function. Type of study/level of evidence Therapeutic IV.
The carbon, nitrogen, and oxygen K-edge spectra were measured for aqueous solutions of glycine by total electron yield near-edge X-ray absorption fine structure (TEY NEXAFS) spectroscopy. The bulk ...solution pH was systematically varied while maintaining a constant amino acid concentration. Spectra were assigned through comparisons with both previous studies and ab initio computed spectra of isolated glycine molecules and hydrated glycine clusters. Nitrogen K-edge solution spectra recorded at low and moderate pH are nearly identical to those of solid glycine, whereas basic solution spectra strongly resemble those of the gas phase. The carbon 1s → π*C O transition exhibits a 0.2 eV red shift at high pH due to the deprotonation of the amine terminus. This deprotonation also effects a 1.4 eV red shift in the nitrogen K-edge at high pH. Two sharp preedge features at 401.3 and 402.5 eV are also observed at high pH. These resonances, previously observed in the vapor-phase ISEELS spectrum of glycine, have been reassigned as transitions to σ* bound states. The observation of these peaks indicates that the amine moiety is in an acceptor-only hydrogen bond configuration at high pH. At low pH, the oxygen 1s → π*C O transition exhibits a 0.25-eV red shift due to the protonation of the carboxylic acid terminus. These spectral differences indicate that the variations in electronic structure observed in the NEXAFS spectra are determined by the internal charge state and hydration environment of the molecule in solution.
Nilsson et al. raise two central issues regarding our recent paper on the energetics of hydrogen bond (H bond) rearrangements in normal and supercooled liquid water. The first concerns the quality of ...our temperature- dependent x-ray absorption (XA) spectra, which Nilsson et al. argue exhibit nonlinear saturation effects. The second point concerns the appropriateness of the spectral analysis we employed in, wherein it was assumed that specific H- bonding configurations are spectrally resolvable.
It was recently suggested that liquid water primarily comprises hydrogen-bonded rings and chains, as opposed to the traditionally accepted locally tetrahedral structure (Wernet et al. Science 2004, ...304, 995). This controversial conclusion was primarily based on comparison between experimental and calculated X-ray absorption spectra (XAS) using computer-generated ice-like 11-molecule clusters. Here we present calculations which conclusively show that when hydrogen-bonding configurations are chosen randomly, the calculated XAS does not reproduce the experimental XAS regardless of the bonding model employed (i.e., rings and chains vs tetrahedral). Furthermore, we also present an analysis of a recently introduced asymmetric water potential (Soper, A. K. J. Phys.: Condens. Matter 2005, 17, S3273), which is representative of the rings and chains structure, and make comparisons with the standard SPC/E potential, which represents the locally tetrahedral structure. We find that the calculated XAS from both potentials is inconsistent with the experimental XAS. However, we also show the calculated electric field distribution from the rings and chains structure is strongly bimodal and highly inconsistent with the experimental Raman spectrum, thus casting serious doubt on the validity of the rings and chains model for liquid water.
We present the combined results on electron-pair production in 158 GeV/n Pb-Au (\(\sqrt{s}\) = 17.2 GeV) collisions taken at the CERN SPS in 1995 and 1996, and give a detailed account of the data ...analysis. The enhancement over the reference of neutral meson decays amounts to a factor of 2.31 \(\pm0.19 (stat.)\pm0.55 (syst.)\pm0.69 (decays)\) for semi-central collisions (28\(\%\)\(\sigma/\sigma_{geo}\)) when yields are integrated over m > 200 MeV/c2 in invariant mass. The measured yield, its stronger-than-linear scaling with \(N_{\rm ch}\), and the dominance of low pair pt strongly suggest an interpretation as thermal radiation from pion annihilation in the hadronic fireball. The shape of the excess centring at \(m\approx\) 500 MeV/c2, however, cannot be described without strong medium modifications of the \(\rho\) meson. The results are put into perspective by comparison to predictions from Brown-Rho scaling governed by chiral symmetry restoration, and from the spectral-function many-body treatment in which the approach to the phase boundary is less explicit.
Purpose With advances in tools and techniques, percutaneous screw fixation of nondisplaced fractures of the scaphoid waist has gained increasing popularity in recent years as an alternative to ...prolonged cast immobilization or open reduction and internal fixation. Many reports cite low complication rates, including no complications in some series. The purpose of this study was to evaluate the complications encountered with dorsal percutaneous cannulated screw fixation of nondisplaced scaphoid waist fractures. Methods A retrospective chart review was performed for 24 patients who had surgery performed by a single surgeon over a 5-year period. All cases involved dorsal percutaneous cannulated screw fixation of nondisplaced (<1 mm) fractures of the scaphoid waist. Complications were rated a priori as major or minor based on modifications of established criteria. Results The overall complication rate was 29%; there were 21% (5/24) major complications and 8% (2/24) minor complications. Major complications consisted of 1 case of nonunion, 3 cases involving hardware problems, and 1 case of postoperative fracture of the proximal pole of the scaphoid. Minor complications included intraoperative equipment breakage—1 case involving a screw and 1 case involving a guide wire. Conclusions Complications in dorsal percutaneous cannulated screw fixation of scaphoid fractures may be more common than previously reported. Type of study/level of evidence Therapeutic IV.
Regional anesthesia has become the preferred method of anesthesia for many upper extremity operations and generally results in decreased hospital stays, postoperative opioid requirement, and ...postoperative nausea. Complications of regional anesthesia are rarely reported in the literature, possibly because of limited anesthesiologist-patient follow-up. Three cases of suprascapular nerve palsy after ultrasound-guided supraclavicular nerve block for routine outpatient upper extremity surgery are reported. All cases occurred in men who originally presented with shoulder pain, which resolved with time, followed by weakness in the supraspinatus and infraspinatus, which improved over time but did not resolve. One case resulted in ipsilateral phrenic nerve palsy as well. A review of the literature on the subject accompanies the report of these 3 cases.
The nitrogen K-edge spectra of aqueous proline and diglycine solutions have been measured by total electron yield near-edge X-ray absorption fine structure (NEXAFS) spectroscopy at neutral and high ...pH. All observed spectral features have been assigned by comparison to the recently reported spectrum of aqueous glycine and calculated spectra of isolated amino acids and hydrated amino acid clusters. The sharp preedge resonances at 401.3 and 402.6 eV observed in the spectrum of anionic glycine indicate that the nitrogen terminus is in an “acceptor-only” configuration, wherein neither amine proton is involved in hydrogen bonding to the solvent, at high pH. The analogous 1s → σ*NH preedge transitions are absent in the NEXAFS spectrum of anionic proline, implying that the acceptor-only conformation observed in anionic glycine arises from steric shielding induced by free rotation of the amine terminus about the glycine CN bond. Anionic diglycine solutions exhibit a broadened 1s → π*CN resonance at 401.2 eV and a broad shoulder resonance at 403 eV, also suggesting the presence of an acceptor-only species. Although this assignment is not as unambiguous as for glycine, it implies that the nitrogen terminus of most proteins is capable of existing in an acceptor-only conformation at high pH. The NEXAFS spectrum of zwitterionic lysine solution was also measured, exhibiting features similar to those of both anionic and zwitterionic glycine, and leading us to conclude that the α amine group is present in an acceptor-only configuration, while the end of the butylammonium side chain is fully solvated.
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