The Learning Curve of Third-Generation Percutaneous Chevron and Akin Osteotomy (PECA) for Hallux Valgus.

The learning curve to reach technical proficiency for third-generation percutaneous or minimally invasive chevron and Akin osteotomies (PECA/MICA) is recognized to be steep however it is poorly defined in the literature. This study is a retrospective review of the first 58 consecutive PECA cases of a single surgeon. The primary outcome was the number of cases required to reach technical proficiency as defined by the operation time. Secondary outcomes included radiation exposure, radiographic deformity correction, and complication rates. Between November 2017 and March 2019, 61 consecutive PECA cases were performed with outcome data available for 58 of these (95%). Technical proficiency was reached after 38 cases. Operation time and radiation exposure significantly decreased after this transition point (p < .05). There was no difference in complication rate or radiographic deformity correction regardless of position along the learning curve (p > .05). In conclusion, the mean number of cases required to reach technical proficiency in third-generation PECA is 38 cases. The complication rate does not correlate to the number of cases performed, therefore surgeons interested in learning minimally invasive surgery can be reassured that there is unlikely to be an additional risk of harm to a patient during the learning curve.

Pattern Formation in Polymerizing Actin Flocks: Spirals, Spots, and Waves without Nonlinear Chemistry.

We propose a model solely based on actin treadmilling and polymerization which describes many characteristic states of actin-wave formation: spots, spirals, and traveling waves. In our model, as in experiments on cells recovering motility following actin depolymerization, we choose an isotropic low-density initial condition; polymerization of actin filaments then raises the density towards the Onsager threshold where they align. We show that this alignment, in turn, destabilizes the isotropic phase and generically induces transient actin spots or spirals as part of the dynamical pathway towards a polarized phase which can either be uniform or consist of a series of actin-wave trains (flocks). Our results uncover a universal route to actin-wave formation in the absence of any system-specific nonlinear biochemistry, and it may help to understand the mechanism underlying the observation of actin spots and waves in vivo. They also suggest a minimal setup to design similar patterns in vitro.

African land-cover classification using satellite data.

Data from the advanced very-high-resolution radiometer sensor on the National Oceanic and Atmospheric Administration's operational series of meteorological satellites were used to classify land cover and monitor vegetation dynamics for Africa over a 19-month period. There was a correspondence between seasonal variations in the density and extent of green-leaf vegetation and the patterns of rainfall associated with the movement of the Intertropical Convergence Zone. Regional variations, such as the 1983 drought in the Sahel of westem Africa, were observed. Integration of the weekly satellite data with respect to time for a 12-month period produced a remotely sensed estimate of primary production based upon the density and duration of green-leaf biomass. Eight of the 21-day composited data sets covering an 11-month period were used to produce a general land-cover classification that corresponded well with those of existing maps.

Production of malachite green oxalate and leucomalachite green reference materials certified for purity.

Malachite green oxalate (MG oxalate) and leucomalachite green (LMG) have been prepared and certified as pure reference materials. The purities of MG oxalate and LMG were assessed by high-performance liquid chromatography-diode array detection (HPLC-DAD), nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC), Karl Fischer titration, ashing and thermogravimetric analysis (TGA). MG oxalate was purified by supercritical fluid extraction (SFE). Prior to purification, commercial MG oxalate purity was estimated to be about 90%. The main impurities present in SFE-purified MG oxalate were identified and quantified using HPLC-DAD. The main impurities were found to be monode-MG (monodemethylated MG oxalate synthesis impurity), 4-(dimethylamino)benzophenone (4-DMABP), MG-carbinol and LMG. The homogeneity of both reference materials was also determined. Issues associated with the stability of LMG and MG oxalate in solution forced an extensive study investigating different parameters i.e. solvent, acid, analyte concentration and temperature. MG oxalate (100 microg/mL) was found to be stable in acetonitrile containing 1% v/v glacial acetic acid for at least 155 days and LMG (100 microg/mL) was stable in acetonitrile for at least 133 days. The final purity value for MG oxalate was 94.3 +/- 1.4% m/m at the 95% confidence interval (or 67% m/m if MG cation is reported). For LMG, the certified purity was found to be 98.8 +/- 0.8% m/m at the 95% confidence interval.

Increased abundance of translation machinery in stem cell-derived neural progenitor cells from four schizophrenia patients.

The genetic and epigenetic factors contributing to risk for schizophrenia (SZ) remain unresolved. Here we demonstrate, for the first time, perturbed global protein translation in human-induced pluripotent stem cell (hiPSC)-derived forebrain neural progenitor cells (NPCs) from four SZ patients relative to six unaffected controls. We report increased total protein levels and protein synthesis, together with two independent sets of quantitative mass spectrometry evidence indicating markedly increased levels of ribosomal and translation initiation and elongation factor proteins, in SZ hiPSC NPCs. We posit that perturbed levels of global protein synthesis in SZ hiPSC NPCs represent a novel post-transcriptional mechanism that might contribute to disease progression.

Mortality and career radiation doses for workers at a commercial nuclear power plant: feasibility study.

Career radiation doses for 8,961 male workers at the Calvert Cliffs Nuclear Power Plant (CCNPP) were determined for both utility (n = 4,960) and contractor (n = 4,001) employees. Workers were followed from the time of first employment at CCNPP (including plant construction) to the end of 1984 (mean follow-up = 5.4 y). Plant operation began in 1975. The mean duration of employment was 1.9 y at CCNPP and 3.1 y in the nuclear industry. Career radiation doses were determined from dosimetry records kept by the utility company and the U.S. Nuclear Regulatory Commission (NRC). For all exposed workers, the average career dose was 21 mSv and was higher for contractor (30 mSv) than utility (13 mSv) workers. Career doses were also higher among those employed in the nuclear industry for greater than or equal to 15 y (111 mSv) and among workers classified as health physicists (56 mSv). Cumulative doses of greater than or equal to 50 mSv were received by 12% of the workers; the maximum career dose reported was 470 mSv. The availability of social security numbers for practically all employees facilitated record-linkage methods to determine mortality; 161 deaths were identified. On average the workers experienced mortality from all causes that was 15% less than that of the general population of the U.S., probably due to healthier members of the population being selected for employment. Our investigation demonstrates that historical information is available from which career doses could be constructed and that, in principle, it is feasible to conduct epidemiologic studies of nuclear power plant workers in the U.S. Although difficult, the approach taken could prove useful until such time as a comprehensive registry of U.S. radiation workers is established.

Orthopedic trauma: a family practice perspective.

It is well documented that residency-trained family physicians can effectively manage the majority of nonsurgical acute orthopedic injuries with a relatively small rate of consultation. The frequency of both fracture location and orthopedic review in our series are remarkably similar to the study from NRMC Charleston reported in 1981. Our program, however, is unique because of the comprehensive management, 3-year continuous training, and multidimensional educational experience. A critical element to the program is the excellent working relationship shared by the family practice and orthopedic departments. A clinic similar to the Davis Grant USAF Medical Center cast clinic could be implemented easily and would better train the family practice resident to manage nonsurgical orthopedic trauma.

Trauma unit emergency doctor airway management.

OBJECTIVES: To audit indications for and practice (in terms of training/qualification) of definitive airway management compared with current UK practices. DESIGN: Consecutive observational study. SETTING: Tygerberg Academic Hospital Trauma Service, Western Cape. SUBJECTS: All trauma patients either arriving intubated or requiring intubation at the Trauma unit during the period 1 - 31 August 2006. OUTCOME MEASURES: A data collection proforma was completed either at the time of intubation or from medical records. Results. Fifty-seven patients required definitive airway management. In the unit 32 patients (56%) were intubated by emergency medicine registrars or medical officers, with rapid sequence intubations (RSIs) in all 32 (100%). Seven patients (12.3%) were intubated by paramedics pre-hospital, and 18 patients (31.6%) were intubated at referring hospitals by non-anaesthetists. Endotracheal intubation was successful in 55 patients (96.4%). Two patients (3.6%) could not be intubated and therefore underwent surgical cricothyroidotomy at the unit. Clinical outcomes included 12 patients (21%) extubated for ward transfer, 7 patients (12.3%) admitted to an intensive care unit (ICU), 21 patients (36.8%) taken for surgery, and 17 patients (29.8%) died. Motor vehicle accident (MVA) was the predominant mechanism of injury, accounting for 30 (52.6%) patients, while 16 patients (28.1%) had penetrating injuries (gunshot and/or stab wounds), 6 patients (10.5%) had blunt trauma, and the remaining 5 patients (8.8%) suffered serious burns. CONCLUSION: The most common indication for intubation was a Glasgow Coma Score (GCS) of less than 8, typically in the polytrauma patient with suspected head injury due to MVA. Emergency doctors managed 100% of definitive airway in-hospital, and RSI was the favoured method. This differs greatly from the UK where non-anaesthetists only perform between 31% and 56% of trauma intubations, with the rest performed by anaesthetists. Outcome was, however, similar to that described in the literature.

Is there a correlation between age and D-aspartic acid in human knee cartilage?

L-Aspartic acid (L-Asp) is one of the fastest racemizing amino acids such that the abnormal D-form (D-Asp) has been found in stable biological human tissues such as dentin in teeth, eye lens and brain. Earlier reports showed that there was a linear correlation between age and D-Asp in teeth. We have previously reported that significant levels of D-Asp were found in normal and osteoarthritic knee cartilage. Since cartilage is a slow regenerating tissue, we hypothesized that D-Asp should accumulate in knee cartilage and that there might be a correlation between the age of the person and the amount of D-Asp found in cartilage. Our analysis of approximately 100 samples of normal knee cartilage showed that there are detectable amounts of D-Asp (2-4% of total Asp) in knee cartilage. However, there was only a slight correlation (r = 0.35) between the age of the person and the amount of D-Asp (nmoles/g). Surprisingly, there was a better correlation between age and the amount of D-Asp in the male subjects (r = 0.57) than in the female subjects (r = 0.21).