Is the 'safe zone' identified in preoperative computed tomography helpful for choosing optimal implant for fixation of radial head fracture?

The purpose of this study is to assess the clinical significance of the radiologic safe zone based on computed tomography and to compare the outcomes of three different implants for fixation of isolated radial head fractures. We retrospectively reviewed 367 patients who underwent internal fixation for isolated radial head fractures. We newly defined two subtypes of Mason type II fractures associated with the radiographic safe zone (IIA, two-part fracture allowing for safe fixation of plate; IIB, two-part fracture not allowing for safe fixation). 170 patients (CCS group, n = 82; HCS group, n = 31; plate group, n = 57) were investigated with no significant differences in demographics. The range of pronation and supination at 1 month postoperatively (P = 0.04 and P = 0.04) and the range of supination at 6 and 12 months postoperatively (P = 0.03 and P = 0.03) were significantly smaller in the plate group. In Mason type IIB fractures, the average MEPS was higher in the CCS and HSC groups than in the plate group (P = 0.01 and P = 0.02). And the average DASH score was lower in the CCS and HCS groups (P < 0.01 and P < 0.01). Evaluation of the radiologic safe zone is potentially helpful in selecting better surgical fixation option. For type III fractures, 2.3-mm cortical screws would be a better option than Acutrak screws. Plates would not be suitable for type IIB radial head fractures.

Correlation between extension-block K-wire insertion angle and postoperative extension loss in mallet finger fracture.

INTRODUCTION: Extension-block pinning represents a simple and reliable surgical technique. Although this procedure is commonly performed successfully, some patients develop postoperative extension loss. To date, the relationship between extension-block Kirschner wire (K-wire) insertion angle and postoperative extension loss in mallet finger fracture remains unclear. HYPOTHESIS: We aimed to clarify this relationship and further evaluate how various operative and non-operative factors affect postoperative extension loss after extension-block pinning for mallet finger fracture. MATERIALS AND METHOD: A retrospective study was conducted to investigate a relationship between extension block K-wire insertion angle and postoperative extension loss. The inclusion criteria were: (1) a dorsal intra-articular fracture fragment involving 30% of the base of the distal phalanx with or without volar subluxation of the distal phalanx; and (2) <3 weeks delay from the injury without treatment. Extension-block K-wire insertion angle and fixation angle of the distal interphalangeal (DIP) joint were assessed using lateral radiograph at immediate postoperative time. Postoperative extension loss was assessed by using lateral radiograph at latest follow-up. Extension-block K-wire insertion angle was defined as the acute angle between extension block K-wire and longitudinal axis of middle phalangeal head. DIP joint fixation angle was defined as the acute angle between the distal phalanx and middle phalanx longitudinal axes. RESULTS: Seventy-five patients were included. The correlation analysis revealed that extension-block K-wire insertion angle had a negative correlation with postoperative extension loss, whereas fracture size and time to operation had a positive correlation (correlation coefficient for extension block K-wire angle: -0.66, facture size: +0.67, time to operation: +0.60). When stratifying patients in terms of negative and positive fixation angle of the DIP joint, the independent t-test showed that mean postoperative extension loss is -3.67° and +4.54° (DIP joint fixation angles of <0° and ≥0°, respectively, P=0.024). When stratifying patients in terms of extension-block K-wire insertion angle (30°, 30°-40°, >40°), ANOVA showed significantly less postoperative extension loss for higher insertion angles (>40°) than for medium insertion angles (30°-40°). Mean postoperative extension loss difference between higher insertion angle (>40°) and medium insertion angle (30°-40°) was 11° (P=0.002). DISCUSSION: Using an insertion angle of the extension-block K-wire of 40°-45° and a slightly hyperextended position of the DIP joint may help reducing postoperative extension loss. LEVEL OF EVIDENCE: Therapeutic level III.

The relationship of trigger finger and flexor tendon volar migration after carpal tunnel release.

It has been suggested that the increased frequency of trigger finger (TF) after carpal tunnel release (CTR) may be caused by the volar migration of the flexor tendons at the wrist altering the tendon biomechanics at the A1 pulley. This hypothesis has not been validated. We performed pre- and post-operative ultrasonography (USG) on the affected wrists of 92 patients who underwent CTR. Pre-operative USG was performed in neutral with no tendon loading; post-operative USG was performed in neutral unloaded and in various positions of wrist flexion whilst loading the flexor tendons with gripping. The mean volar migration of the flexor tendons after CTR was 2.2 (SD 0.4) mm in the unloaded neutral position. It was 1.8 (SD 0.4) mm in patients who did not develop TF and 2.5 (SD 0.5) mm in those who did (p = 0.0067). In loaded wrist flexion, the mean volar migration of flexor tendons after CTR in patients who did not develop TF and those who did was 2.1 and 3.0 mm in 0° flexion; 3.2 and 3.9 mm in 15° flexion; 4.3 and 5.1 mm in 30° flexion; and 4.9 and 5.8 mm in 45° flexion, respectively. There were significant differences between patients with and without TF at each flexion angle. Our data indicate that patients with greater volar migration of the flexor tendons after CTR are more likely to develop TF. This conclusion supports the hypothesis that the occurrence of TF after CTR may be caused by the bowstringing effects of the flexor tendons.

Is multimodal analgesia as effective as postoperative patient-controlled analgesia following upper extremity surgery?

INTRODUCTION: The present prospective study compared the clinical outcomes between a multimodal analgesia group and a patient-controlled analgesia (PCA) group for postoperative pain control in upper extremities surgery. HYPOTHESIS: Multimodal analgesia including pre-emptive analgesic can provide similar or superior analgesic effects and a lower incidence of adverse reactions than PCA following upper extremity surgery. PATIENTS AND METHODS: Sixty-one patients undergoing upper extremity surgery were randomized to 2 perioperative analgesic groups (multimodal analgesia and PCA). We compared the clinical outcomes: use of additional pain rescue, opioid-related complication rate, and patient's satisfaction between the 2 groups. RESULTS: No significant differences on the resting and exercise pain scores between the two groups. Also, there were no differences regarding additional pain rescue during postoperative day (POD) 1, 2 and achievement of rehabilitation protocol in both groups. However, use of additional pain rescue in PCA group was increased significantly after PCA removal. Moreover, there was significant difference in the incidence of opioid-related complications on operation day and at POD 1. At discharge, multimodal analgesia group showed significantly greater satisfaction than PCA group. DISCUSSION: Perioperative pain management following upper extremity surgery through the multimodal analgesia could be an acceptable alternative method that can provide good results.

Use of the radial groove view intra-operatively to prevent damage to the extensor pollicis longus tendon by protruding screws during volar plating of a distal radial fracture.

The aims of this study were to assess the efficacy of a newly designed radiological technique (the radial groove view) for the detection of protrusion of screws in the groove for the extensor pollicis longus tendon (EPL) during plating of distal radial fractures. We also aimed to determine the optimum position of the forearm to obtain this view. We initially analysed the anatomy of the EPL groove by performing three-dimensional CT on 51 normal forearms. The mean horizontal angle of the groove was 17.8° (14° to 23°). We found that the ideal position of the fluoroscopic beam to obtain this view was 20° in the horizontal plane and 5° in the sagittal plane. We then intra-operatively assessed the use of the radial groove view for detecting protrusion of screws in the EPL groove in 93 fractures that were treated by volar plating. A total of 13 protruding screws were detected. They were changed to shorter screws and these patients underwent CT scans of the wrist immediately post-operatively. There remained one screw that was protruding. These findings suggest that the use of the radial groove view intra-operatively is a good method of assessing the possible protrusion of screws into the groove of EPL when plating a fracture of the distal radius.

Expression of a recombinant Phoneutria toxin active in calcium channels.

PnTx3-4 is a toxin isolated from the venom of the spider Phoneutria nigriventer that blocks N-, P/Q-, and R-type voltage-gated calcium channels and has great potential for clinical applications. In this report we used the SUMO system to express large amounts of recombinant PnTx3-4 peptide, which was found in both soluble and insoluble fractions of bacterial extracts. We purified the recombinant toxin from both fractions and showed that the recombinant peptide showed biological activity similar to the native PnTx3-4. In silico analysis of the primary sequence of PnTx3-4 indicated that the peptide conforms to all the criteria of a knottin scaffold. Additionally, circular dichroism spectrum analysis of the recombinant PnTx3-4 predicted that the toxin structure is composed of approximately 53% turns/unordered, 31% α-helix and 16% ß-strand, which is consistent with predicted model of the PnTx3-4 knottin scaffold available at the knottin database (http://knottin.cbs.cnrs.fr). These studies provide the basis for future large scale production and structure-function investigation of PnTx3-4.

Selection of supported cobalt substrates in the presence of oxone for the oxidation of monuron.

The immobilization of cobalt ion on different media to catalyze oxone has been investigated. A probe herbicide, Monuron, was effectively degraded by using Co2+/oxone systems. For Co2+ supported on zeolite, 100% of Monuron could be removed within a 10 min reaction time. However, the recycling of the spent Co-zeolite catalyst using various posttreatments did not give a promising result. This is likely because the zeolite particles in solution have blocked and significantly attenuated the incident UV light from reducing Co3+ to Co2+. On the contrary, the use of cationic resin has minimized these problems. In the process of Co-resin/oxone/UV, faster Monuron decay could be achieved than that in the dark reaction. In the presence of UV, a significant drop of total organic carbon (TOC) was also observed in this approach suggesting an effective and clean process for Monuron mineralization.

The effect of solution pH and peroxide in the TiO2-induced photocatalysis of chlorinated aniline.

Chlorinated anilines are frequently used in the industry as starting materials for chemical synthesis. This type of compounds can end up as pollutants in wastewater. 2-Chloroaniline (2-ClA) was selected irradiating under monochromatic UV light at 300nm. The reaction rate could be enhanced by introducing low level of H(2)O(2) into the UV/TiO(2) system. Excess H(2)O(2) could not increase the HO* generation but retarded the reaction rate. The pH effect was also investigated in UV/TiO(2) and UV/TiO(2)/H(2)O(2) systems. All the experimental results show that pH is a sensitive parameter to the rate of degradation. Low reaction rate at acidic pH could be accounted by the dark adsorption test which has also proven the photocatalysis of TiO(2) may contribute to a two-step process: (1) 2-ClA pre-adsorbed onto TiO(2) and (2) photoexcitation of TiO(2). At high pH, rate enhancement could be observed at UV/TiO(2) system because of the increase generation of HO*. However, the introduction of H(2)O(2) slowdown the decay rate at such alkaline medium.

The use of oxyhalogen in photocatalytic reaction to remove o-chloroaniline in TiO2 dispersion.

Photodecay of o-chloroaniline (o-ClA) in various combinations of UV sources, TiO2, and oxyhalogens was investigated. To improve the conventional photocatalytic process by using UV/TiO2, the addition of oxyhalogens (ClO3(-), BrO3(-) and IO3(-)) into UV/TiO2 system was studied and the effect in such addition is very encouraging for all the selected additives. Oxyhalogens are capable of deferring the electron-hole recombination of TiO2 which significantly improved its catalytic performance. The presence of IO3(-) in UV/TiO2 resulted in the fastest o-ClA decay among three oxhalogens at the same dosage. The decay of o-ClA in UV/TiO2/oxyhalogen process is characterized by a two-stage pseudo-kinetics, where a faster initial decay was followed by a retardation state. A mathematics model was successfully established for the prediction of the two-stage decay of o-ClA in UV/TiO2/IO3(-) with any designed [IO3(-)] concentration.

The partitioning and modelling of pesticide parathion in a surfactant-assisted soil-washing system.

Soil sorption of organic pollutants has long been a problematic in the soil washing process because of its durability and low water solubility. This paper discussed the soil washing phenomena over a wide range of parathion concentrations and several soil samples at various fractions of organic content (foc) levels. When parathion dosage is set below the water solubility, washing performance is stable for surfactant concentrations above critical micelle concentration (cmc) and it is observed that more than 90% of parathion can be washed out when dosage is five times lower than the solubility limit. However, such trends change when non-aqueous phase liquids (NAPL) is present in the system. Parathion extraction depends very much on the surfactant dosage but is not affected by the levels of foc in the system. In between the extreme parathion dosage, a two-stage pattern is observed in these boundary regions. Washing performance is first increased with additional surfactant, but the increase slows down gradually since the sorption sites are believed to be saturated by the huge amount of surfactant in the system. A mathematical model has included foc to demonstrate such behavior and this can be used as a prediction for extraction.

Effects of nonaqueous phase liquids on the washing of soil in the presence of nonionic surfactants.

The removal of malathion from soil by surfactant washing was investigated under various physical-chemical states of the malathion. Three distinctive phases (without nonaqueous phase liquids (NAPL), with NAPL, and the transitional zone of NAPL) were found to be important for a better understanding of the washing process. When there is no NAPL in the system, the washing process is less dependent on the surfactant dose if the applied surfactant concentration is above the critical micelle concentration. The existence of a sorption site boundary, which for the determination of different washing mechanisms, was identified. In the presence of NAPL, the washing performance is generally independent of the organic content (f(oc)) of the soils but is dominated by the concentration of the surfactant used, due to the lesser resistance for mass transfer in NAPL. If the formation of NAPL is marginal, a two-stage washing pattern is observed, which has been quantified by the term 'unit extraction'. For this two-stage system, a mathematical model was derived based on the observed initial unit extraction and final extraction capacity, which eventually resulted in a practical design equation with the use of primary parameters such as f(oc) and surfactant dose.

Comparative bioavailability study of a generic sustained release diclofenac sodium tablet.

The bioavailability of a generic diclofenac sodium sustained release tablet preparation (Zolterol, SR) was compared with the innovator product, Voltaren, SR. Twelve healthy adult male volunteers participated in the study, which was conducted according to a randomized, two-way crossover design with a wash out period of one week. The bioavailability of diclofenac was compared using the parameters area under the plasma concentration-time curve (AUC(0-infinity)), peak plasma concentration (Cmax) and time to reach peak plasma concentration (Tmax). No statistically significant difference was observed for both logarithmically transformed AUC(0-infinity), Cmax values and Tmax value of the two preparations.

Leakage of cement in percutaneous transpedicular vertebroplasty for painful osteoporotic compression fractures.

e analysed the CT scans and radiographs of 76 vertebrae in 49 patients who underwent vertebroplasty for painful osteoporotic compression fractures. Leaks of cement were classified into three types: those via the basivertebral vein (type B), via the segmental vein (type S), and through a cortical defect (type C). More leaks were identified on CT scans than on radiographs by a factor of 1.5 (74/49). Most type-B (93%) and type-S (86%) leaks were missed or underestimated on a lateral radiograph which is usually the only view used during the injection of cement. Of the leaks into the spinal canal, only 7% (2/28) were correctly identified on radiographs. The areas on lateral radiographs where this type of leak may be observed were divided into four zones, and their diagnostic value in predicting a leak into the spinal canal was evaluated. The results showed that cement in the neural foramina had the highest positive predictive value (86%).

Baseline BMD and bone loss at distal radius measured by peripheral quantitative computed tomography in peri- and postmenopausal Hong Kong Chinese women.

The current study was designed to investigate the rate of bone loss in distal radius and its association with baseline volumetric bone mineral density (BMD) and years since menopause (YSM) in peri- and postmenopausal women using precise and multislice peripheral quantitative computed tomography (pQCT; Densiscan 2000). Two hundred and five healthy Hong Kong Chinese perimenopausal ( n = 26) and postmenopausal ( n = 179) women within 10 years of the onset of menopause were recruited. Anthropometric parameters and menstrual status were also measured. The linear regression model derived from the baseline volumetric BMD revealed a significant and slightly better correlation with YSM than age, with a YSM-related annual decline of 2.56%, 1.82% and 0.65% in trabecular BMD (tBMD), integral BMD (iBMD) and cortical BMD (cBMD), respectively. Follow-up measurements after a time interval of 12 months showed that the rate of bone loss was higher than the annual decline in BMD calculated from the baseline BMD, with decreases of 2.89%, 2.16% 0.91% in tBMD, iBMD and cBMD, respectively. Baseline BMD was associated with age or YSM ( r ranges from -0.283 to -0.502; p<0.001 in all cases), but no relationship was found between annual rate of bone loss and age or YSM. The rate of bone loss did not correlate with baseline volumetric BMD values or YSM after dividing the subjects into fast bone losers (with annual tBMD loss > or =3%), normal bone losers (with annual tBMD loss > or = 1% but <3%) or slow bone losers (with annual tBMD loss <1%). The rate of bone loss was greater in both trabecular and cortical bone of postmenopausal women within the first 3 menopausal years but was only significant in the iBMD as compared with perimenopausal and postmenopausal women over 7 years after onset of menopause. The percentage distribution of slow and fast bone losers was not found to be associated with YSM. As a total of only 4 fracture cases were documented, the study could not provide conclusive information on whether perimenopausal and early postmenopausal baseline volumetric BMD or rate of bone loss determines the development of osteoporosis or fracture occurrence.

The mechanisms of rate enhancing and quenching of trichloroethene photodecay in the presence of sensitizer and hydrogen sources.

The reaction mechanisms and rates of trichloroethene (TCE) photodecay in the presence of photosensitizer (acetone, ACE) and hydrogen sources (surfactant and triethylamine, TEA) were investigated. Quantum yields of TCE photodecay in solution with surfactant Brij 35 and optimal ACE dosage are about 25 times higher than in Brij 35 alone. However, with an excess ACE dosage, ACE will act as a light barrier and attenuate the light intensity available for TCE photodegradation. TCE photodegradation follows a two-stage kinetics, in which a lag-phase is followed by a fast decay. The lag-phase distribution depends on initial pH levels and ACE concentrations. The overall TCE removal was found to be higher at high pH level, suggesting that free radical reaction is dominant at high pH levels. The use of additional hydrogen source (TEA) in the reaction can further accelerate the reaction, but overdosing of TEA would quench the reaction. The possible reaction mechanisms of TCE photodecay involving ACE and TEA were proposed, and rateenhancing and rate-quenching models at low and high TEA concentrations respectively were derived based on the proposed mechanism, they were found useful for predicting the TEC decay quantum yields.

Heat stress prevents mitochondrial injury in ATP-depleted renal epithelial cells.

The events that precipitate cell death and the stress proteins responsible for cytoprotection during ATP depletion remain elusive. We hypothesize that exposure to metabolic inhibitors damages mitochondria, allowing proapoptotic proteins to leak into the cytosol, and suggest that heat stress-induced hsp72 accumulation prevents mitochondrial membrane injury. To test these hypotheses, renal epithelial cells were transiently ATP depleted with sodium cyanide and 2-deoxy-D-glucose in the absence of medium dextrose. Recovery from ATP depletion was associated with the release into the cytosol of cytochrome c and apoptosis-inducing factor (AIF), proapoptotic proteins that localize to the intermitochondrial membrane space. Concomitant with mitochondrial cytochrome c leak, a seven- to eightfold increase in caspase 3 activity was observed. In controls, state III mitochondrial respiration was reduced by 30% after transient exposure to metabolic inhibitors. Prior heat stress preserved mitochondrial ATP production and significantly reduced both cytochrome c release and caspase 3 activation. Despite less cytochrome c release, prior heat stress increased binding between cytochrome c and hsp72. The present study demonstrates that mitochondrial injury accompanies exposure to metabolic inhibitors. By reducing outer mitochondrial membrane injury and by complexing with cytochrome c, hsp72 could inhibit caspase activation and subsequent apoptosis.

Direct structure refinement of high molecular weight proteins against residual dipolar couplings and carbonyl chemical shift changes upon alignment: an application to maltose binding protein.

The global fold of maltose binding protein in complex with beta-cyclodextrin has been determined using a CNS-based torsion angle molecular dynamics protocol involving direct refinement against dipolar couplings and carbonyl chemical shift changes that occur upon alignment. The shift changes have been included as structural restraints using a new module, CANI, that has been incorporated into CNS. Force constants and timesteps have been determined that are particularly effective in structure refinement applications involving high molecular weight proteins with small to moderate numbers of NOE restraints. Solution structures of the N- and C-domains of MBP calculated with this new protocol are within approximately 2 A of the X-ray conformation.

The study of rate improvement of trichloroethene (TCE) decay in UV system with hydrogen source.

The photosensitization of trichloroethene (TCE) in the presence of hydrogen source of surfactant and photosensitizer was investigated. Photolysis experiments were conducted with a Rayonet RPR-200 merry-go-round photoreactor at 253.7 nm. Solutions containing fixed amount of TCE and surfactant Brij 35 were exposed to UV illumination with different concentrations of acetone (ACE). Quantum yield in solution with surfactant Brij 35 and optimum ACE dosage is about 25 times higher than that in Brij 35 alone. However, with an excess ACE dosage, it would act as a light barrier which attenuates the light intensity for TCE photodegradation. A mathematical model is therefore developed for the prediction of TCE photodegradation in Brij 35 solution containing various ACE concentrations, in which the remaining fraction of TCE (C/C0) in the system can be determined. Apart from the direct photodegradation, photosensitization is postulated to be another major pathway contributing to the overall decay.

Structural characterization of proteins with an attached ATCUN motif by paramagnetic relaxation enhancement NMR spectroscopy.

The use of a short, three-residue Cu(2+)-binding sequence, the ATCUN motif, is presented as an approach for extracting long-range distance restraints from relaxation enhancement NMR spectroscopy. The ATCUN motif is prepended to the N-termini of proteins and binds Cu(2+) with a very high affinity. Relaxation rates of amide protons in ATCUN-tagged protein in the presence and absence of Cu(2+) can be converted into distance restraints and used for structure refinement by using a new routine, PMAG, that has been written for the structure calculation program CNS. The utility of the approach is demonstrated with an application to ATCUN-tagged ubiquitin. Excellent agreement between measured relaxation rates and those calculated on the basis of the X-ray structure of the protein have been obtained.

The rate improvement and modeling of trichloroethene photodegradation by acetone sensitizer in surfactant solution.

The photodecay of trichloroethene (TCE) in surfactant solution by the help of photosensitizer (acetone, ACE) was investigated and modeled. Apart from the direct photodegradation, photosensitization is presumed to be one of the major mechanisms contributing to overall decay. Quantum yields of TCE photodecay in solution with surfactant Brij 35 and optimal ACE dosage are about 25 times higher than in Brij 35 alone. However, with an excess ACE dosage, ACE will act as a light barrier and attenuate the light intensity available for TCE photodegradation. TCE photodegradation follows a two-stage kinetics, in which a lag phase is followed by a fast decay. Mathematical models were developed for the prediction of the two-stage photodegradation, in which the remaining fraction of TCE (C/C0) in the system becomes predictable.