The nomenclature for intra-articular vertical impact fractures of the tibial plafond: pilon versus pylon

Although most of the controversy surrounding the treatment of intra-articular, vertical impact fractures of the lower tibia is due to the difficult clinical problems they pose, there is a minor, ongoing dispute regarding nomenclature. In the last several decades, these fractures have been called either pilon or pylon fractures. This study traces the etymology of both terms and relates them to their usage in the orthopaedic literature. Based on the origins of each word, and how they were introduced into the orthopaedic literature, it is concluded that the correct term for an intra-articular, vertical impact fracture of the lower tibia is pilon fracture.     

Novel Scaled Average Bioequivalence Limits Based on GMR and Variability Considerations

PURPOSE: i) To develop novel approaches for the construction of bioequivalence (BE) limits incorporating both the intrasubject variability and the geometric mean ratio (GMR), and ii) to assess the performance of the novel approaches in comparison to several scaled BE procedures and the classic unscaled average BE. METHODS: Plots of the BE limits or the extreme GMR values accepted as a function of the coefficient of variation (CV) were constructed for published and the developed scaled procedures. Two-period crossover BE investigations with 12, 24, or 36 subjects were simulated with assumptions of a CV 10%, 20%, 30%, or 40%. The decline in the percentage of accepted studies was recorded as the true GMR for the two formulations was raised from 1.00 to 1.50. Acceptance of BE was evaluated by published and the developed scaled procedures, and, for comparison, by the unscaled average BE. RESULTS: Two GMR-dependent BE limits are proposed for the evaluation of average BE: i) BELscG1 with Ln(Upper, Lower BE limit) = +/-[(5 - 4GMR)0.496s + Ln(1.25)], and ii) BELscG2 with Ln(Upper, Lower BE limit) = +/-[(3 - 2GMR)(0.496s + Ln(1.25))], where s is the square root of the intrasubject variance. The range of BE limits becomes narrower as GMR values deviate from unity, and increases with variability. The two new approaches exhibit the highest statistical power at low CV values. At high levels of variability, BELscG1 and BELscG2 show high statistical power, as well as the lowest percentages of acceptance among the scaled methods when GMR = 1.25. The latter becomes more obvious when a large number of subjects is incorporated in the studies. CONCLUSIONS: The GMR and CV estimates of the BE study can be used in conjunction with the GMR vs. CV plot for the assessment of average BE. The new approaches, BELscG1 and BELscG2, appear to be highly effective at all levels of variation investigated.     

Hospital response to chemical terrorism: personal protective equipment, training, and operations planning

BACKGROUND: Hospitals distant from the immediate site of an incident involving a hazardous materials (HAZMATs) release which could include chemical warfare agents, must develop emergency response plans (ERPs) to protect healthcare professionals if they receive potentially contaminated victims. The ERP must address OSHA, EPA, and JCAHO requirements. METHODS: The VHA convened groups to develop a hazard and exposure assessment, identify actions for compliance with existing regulatory standards, and review site and operational planning issues. Exposure modeling results were used to derive relationships between operational parameters (time and distance from sites/sources) and potential exposure for healthcare workers. RESULTS: According to exposure modeling, level C personal protective equipment is adequate to protect hospital staff distant from the chemical release site. Decontamination runoff and contaminated clothing should also be controlled to limit exposure. CONCLUSIONS: Development and coordination of ERPs must include the local emergency planning committee, with clear assignment of tasks, locations, and training in order to prevent exposures to healthcare workers.     

Intracytoplasmic Injection Using Spermatids and Subsequent Pregnancies: Round Versus Elongated Spermatids

The purpose of this clinical trial study was to report the outcome of intracytoplasmic injection of round (RS) and elongated (ES) spermatids retrieved from the testis of nonobstructive men. Seven and three cycles using RS and ES injections were performed, respectively. Only one cycle utilizing the late stage of ES (Sd2) resulted in an on-going pregnancy. The remarkable low success rate following RS microinjection was established in this study.     

A Reappraisal of Drug Release Laws Using Monte Carlo Simulations: The Prevalence of the Weibull Function

Purpose. To verify the Higuchi law and study the drug release from cylindrical and spherical matrices by means of Monte Carlo computer simulation. Methods. A one-dimensional matrix, based on the theoretical assumptions of the derivation of the Higuchi law, was simulated and its time evolution was monitored. Cylindrical and spherical three-dimensional lattices were simulated with sites at the boundary of the lattice having been denoted as leak sites. Particles were allowed to move inside it using the random walk model. Excluded volume interactions between the particles was assumed. We have monitored the system time evolution for different lattice sizes and different initial particle concentrations. Results. The Higuchi law was verified using the Monte Carlo technique in a one-dimensional lattice. It was found that Fickian drug release from cylindrical matrices can be approximated nicely with the Weibull function. A simple linear relation between the Weibull function parameters and the specific surface of the system was found. Conclusions. Drug release from a matrix, as a result of a diffusion process assuming excluded volume interactions between the drug molecules, can be described using a Weibull function. This model, although approximate and semiempirical, has the benefit of providing a simple physical connection between the model parameters and the system geometry, which was something missing from other semiempirical models.     

Impact of chronic DDD pacing on time-domain indexes of heart rate variability in patients with hypertrophic obstructive cardiomyopathy

The aim of this study was to examine whether DDD pacing affects time-domain indexes of heart rate variability (HRV) in patients with hypertrophic obstructive cardiomyopathy (HOCM). We studied 11 patients (7 men, age 52 +/- 8 years) with HOCM refractory to drugs. In all patients a DDD pacemaker was implanted and the atrioventricular delay was programmed to ensure a full ventricular activation sequence. Time-domain indexes of HRV (mean NN, SDANN, SDNN, SD, rMSSD, pNN50) were determined from 24-hour Holter recordings 3 days before and 1 year after pacemaker implantation. The pacemaker was turned off during the second recordings. The same indexes were determined in ten healthy controls at the same time points. The controls showed no significant differences in any of the measured parameters between the two time points. The HOCM patients showed an increase in SD (from 27 +/- 13 to 41 +/- 13 ms, P < 0.001), rMSSD (from 18 +/- 5 to 32 +/- 8 ms, P < 0.001), and pNN50 (from 1.03 +/- 1.06 to 8.52 +/- 4.84%, P < 0.0001). As a result, the values of these three parameters, which were lower in the HOCM patients than in the controls before pacing, were restored to normal levels by the end of the study. In conclusion, our findings indicate that long-term pacing in HOCM patients restores the sympathovagal balance in the heart by increasing vagal activity.