A randomized controlled trial of the effect of preoperative dexmedetomidine on the half maximal effective concentration of propofol for successful i-gel insertion without muscle relaxants.

BACKGROUND: Dexmedetomidine is a useful anesthetic adjuvant for general anesthesia. We determined whether preoperative dexmedetomidine administration could reduce the half maximal effective concentration (EC50) of propofol for successful i-gel insertion without muscle relaxants. METHODS: Thirty-seven patients were randomly allocated to one of two groups. In the dexmedetomidine group (n = 19), dexmedetomidine (1 µg/kg) was loaded for 10 min preoperatively. In the control group (n = 20), the same volume of 0.9% normal saline was administered in the same manner. The EC50 of propofol for successful i-gel insertion was determined using Dixon's up-and-down method. The EC50 of propofol was calculated as the midpoint concentration after at least six crossover points had been obtained. For successful i-gel insertion, all of the following four factors were required­(1) no major movement of the body within 1 min of insertion, (2) no significant resistance to mouth opening, (3) cough ≤2, and (4) visible square wave capnogram without air leakage at a peak airway pressure of <10 cmH2O. Mean blood pressure (MBP) and heart rate (HR) were monitored during the peri-insertion period of i-gel. RESULTS: The EC50 of propofol for successful i-gel insertion was 3.18 µg/mL in the dexmedetomidine group and 6.75 µg/mL in the control group (p < 0.001). The incidence of hypotension (MBP <80% of the baseline) during the peri-insertion period of i-gel was higher in the control group (p = 0.001), whereas the incidence of bradycardia (HR <80% of the baseline) was higher in the dexmedetomidine group (p = 0.001). CONCLUSIONS: Preoperative dexmedetomidine reduced the EC50 of propofol for successful i-gel insertion without muscle relaxants.

Corticoplasty for improved appearance of hands with Ollier disease.

PURPOSE: Only a few treatment options are available for Ollier disease, especially for improving appearance. The purpose of this study was to evaluate the efficacy of partial resection of the cortical bone with curettage of the tumor (corticoplasty) for treating hand deformity in Ollier disease. METHODS: Five hands (3 patients, 30 metacarpals and phalanges) were examined. Windows of thin cortical bone were elevated, the tumors were excised, and the cortex was trimmed and replaced to enhance the appearance. Artificial bone substitute was used as the graft material for 17 lesions to fill the vacant medullary cavity. The other 13 bones had corticoplasty without grafting. Reduction of bone diameter on radiographs and patient satisfaction were rated after an average of 24 months. RESULTS: On average, bony union was achieved 9 weeks after surgery (range, 4-12) in all cases. Morphologic changes on radiographs were rated as excellent or good. Complications and tumor recurrence were not observed, and the range of finger motion and grip strength did not decrease. The level of satisfaction with the outcome was very satisfied for 4 hands and satisfied for the remaining hand. CONCLUSIONS: Corticoplasty for Ollier disease resulted in cosmetic improvement without functional deterioration.

Graphene oxide/mussel foot protein composites for high-strength and ultra-tough thin films.

Graphene oxide (GO)-based composite materials have become widely popular in many applications due to the attractive properties of GO, such as high strength and high electrical conductivity at the nanoscale. Most current GO composites use organic polymer as the matrix material and thus, their synthesis suffers from the use of organic solvents or surfactants, which raise environmental and energy-consumption concerns. Inspired by mussel foot proteins (Mfp) secreted by the saltwater mussel, Mytilus galloprovincialis and by recent advances in microbial protein production, we developed an aqueous-based green synthesis strategy for preparing GO/Mfp film composites. These GO/Mfp films display high tensile strength (134-158 MPa), stretchability (~ 26% elongation), and high toughness (20-24 MJ/m3), beyond the capabilities of many existing GO composites. Renewable production of Mfp proteins and the facile fabrication process described provides a new avenue for composite material synthesis, while the unique combination of mechanical properties of GO/Mfp films will be attractive for a range of applications.

Spontaneous bone regeneration after surgical extraction of a horizontally impacted mandibular third molar: a retrospective panoramic radiograph analysis.

BACKGROUND: The mandibular third molar (M3) is typically the last permanent tooth to erupt because of insufficient space and thick soft tissues covering its surface. Problems such as alveolar bone loss, development of a periodontal pocket, exposure of cementum, gingival recession, and dental caries can be found in the adjacent second molars (M2) following M3 extraction. The specific aims of the study were to assess the amount and rate of bone regeneration on the distal surface of M2 and to evaluate the aspects of bone regeneration in terms of varying degree of impaction. METHODS: Four series of panoramic radiographic images were obtained from the selected cases, including images from the first visit, immediately after extraction, 6 weeks, and 6 months after extraction. ImageJ software® (NIH, USA) was used to measure linear distance from the region of interest to the distal root of the adjacent M2. Radiographic infrabony defect (RID) values were calculated from the measured radiographic bone height and cementoenamel junction with distortion compensation. Repeated measures of analysis of variance and one-way analysis of variance were conducted to analyze the statistical significant difference between RID and time, and a Spearman correlation test was conducted to assess the relationship between Pederson's difficulty index (DI) and RID. RESULTS: A large RID (> 6 mm) can be reduced gradually and consistently over time. More than half of the samples recovered nearly to their normal healthy condition (RID ≤ 3 mm) by the 6-month follow-up. DI affected the first 6 weeks of post-extraction period and only showed a significant positive correlation with respect to the difference between baseline and final RID. CONCLUSIONS: Additional treatments on M2 for a minimum of 6 months after an M3 extraction could be recommended. Although DI may affect bone regeneration during the early healing period, further study is required to elucidate any possible factors associated with the healing process. The DI does not cause any long-term adverse effects on bone regeneration after surgical extraction.

Use of free tissue transfers in head and neck reconstruction.

More than 20 different free flaps have been described for head and neck reconstruction including fibula, iliac crest, scapula, radial forearm, rectus abdominis, anterolateral thigh, latissimus dorsi, and jejunum (Head Neck. 2004;26:930). The high success rate and improved functional outcomes seen with free-tissue transfers have made them the workhorse for oromandibular defects (Plast Reconstr Surg. 2002;110:438; Microsurgery. 2004;24:374). In this article, we outline a few of the commonly used free flaps in head and neck reconstruction.

Multi-modal characterization of vasculature and nanoparticle accumulation in five tumor xenograft models.

Preclinical research has demonstrated that nanoparticles and macromolecules can accumulate in solid tumors due to the enhanced permeability and retention effect. However, drug loaded nanoparticles often fail to show increased efficacy in clinical trials. A better understanding of how tumor heterogeneity affects nanoparticle accumulation could help elucidate this discrepancy and help in patient selection for nanomedicine therapy. Here we studied five human tumor models with varying morphology and evaluated the accumulation of 100 nm polystyrene nanoparticles. Each tumor model was characterized in vivo using micro-computed tomography, contrast-enhanced ultrasound and diffusion-weighted and dynamic contrast-enhanced magnetic resonance imaging. Ex vivo, the tumors were sectioned for both fluorescence microscopy and histology. Nanoparticle uptake and distribution in the tumors were generally heterogeneous. Density of functional blood vessels measured by fluorescence microscopy correlated significantly (p = 0.0056) with nanoparticle accumulation and interestingly, inflow of microbubbles measured with ultrasound also showed a moderate but significant (p = 0.041) correlation with nanoparticle accumulation indicating that both amount of vessels and vessel morphology and perfusion predict nanoparticle accumulation. This indicates that blood vessel characterization using contrast-enhanced ultrasound imaging or other methods could be valuable for patient stratification for treatment with nanomedicines.