Prenatal sonographic assessment of early, rapidly growing fetal cervical teratoma

Although malignant transformation of fetal cervical teratoma is extremely rare, perinatal morbidity is high and usually related to the size of the tumour, which may compromise fetal swallowing and subsequently lead to upper airway obstruction. We present a case in which mid-trimester serial sonography demonstrated markedly rapid early growth of a lesion of this type between 17 and 19 weeks' gestation indicating the aggressive nature of this tumour, assisting parental decision to terminate the pregnancy. Histopathology confirmed grade 3 immaturity of the lesion.     

Likelihood of malignant disease for various categories of mammographically detected, nonpalpable breast lesions

To determine the likelihood of malignant disease for mammographically detected, nonpalpable breast lesions, we defined 11 morphologic categories and retrospectively reviewed the mammograms in 859 cases in which biopsy was performed after a wire localization procedure at our institution during 1989 and 1990. Within each category, the total number of lesions and the percentage of cases with a surgical pathologic diagnosis of malignant involvement were as follows: benign calcification, 25 (0% malignant); indeterminate calcification, 200 (22%); malignant calcification, 39 (92%); smooth mass, 84 (1%); irregular mass, 337 (40%); architectural distortion, 45 (47%); asymmetric breast tissue, 37 (3%, or 1 case of asymmetrically prominent ducts); smooth mass with calcification, 3 (0%); irregular mass with calcification, 68 (66%); architectural distortion with calcification, 14 (57%); and asymmetric breast tissue with calcification, 7 (29%). The overall rate of malignant involvement for the 859 cases was 34%. If follow-up examinations rather than biopsies had been done for the lesions categorized as benign calcification, smooth mass, smooth mass with calcification, and asymmetric breast tissue (excluding asymmetrically prominent ducts), the overall positive predictive value would have increased from 34 to 41%, and 148 biopsies would have been deferred (17% of all biopsies). If morphologic criteria are applied to the evaluation of mammographically detected, nonpalpable lesions, the rate of malignant disease at biopsy may reach 40%. This rate correlates with that in recent large series.     

Gentamicin penetration into normal rabbit nucleus pulposus

STUDY DESIGN: Radioactively labeled gentamicin was administered to 24 rabbits to assess the concentration of antibiotic in the nucleus pulposus. OBJECTIVES: The purpose of the study was to investigate the pharmacokinetics of gentamicin penetration into normal rabbit nucleus pulposus. SUMMARY OF BACKGROUND DATA: Disc space infection is a complication of spinal surgery that can be prevented by prophylactic antibiotics. Gentamicin can be used in conjunction with other antibiotics as a prophylactic agent. One previous study demonstrated that a similar antibiotic, tobramycin, penetrates the disc, but no data have been reported on the pharmacokinetics of disc penetration. METHODS: Twenty-four rabbits were given an intravenous injection of gentamicin labeled with iodine 125. Four rabbits were killed at hourly intervals 1 to 6 hours after injection. Specimens of nucleus pulposus, blood, whole liver, and saline-perfused liver were obtained and prepared. The radioactivity in the specimens was measured. RESULTS: The gentamicin concentration in the nucleus pulposus peaked at 2 hours and remained at this level for the duration of the experiment. Twenty percent of the gentamicin recovered from the nucleus pulposus was tissue bound. CONCLUSIONS: Gentamicin concentration in the rabbit nucleus pulposus does not peak until 2 hours after an intravenous bolus of drug. If gentamicin penetrates human nucleus pulposus in a similar fashion, this study could have implications for the timing of administration of this agent for prophylaxis.     

RNA chiropractics

BACKGROUND AND OBJECTIVE: With the increasing use of laser resurfacing, concerns have arisen about the biological hazards associated with the procedure. This study analyzed the potential bacterial and viral exposure to operating room personnel as a result of the laser smoke plume in CO2 laser resurfacing. STUDY DESIGN/MATERIALS AND METHODS: Thirteen consecutive patients underwent CO2 laser resurfacing. A HEPA filter in the smoke evacuator was used to collect specimens of the laser plume smoke for cultures. The study was controlled by a second filter exposed to room air. RESULTS: The 13 patients each had one bacterial, one viral, and one control culture (total, 39 specimens). In the control group, none of the 13 specimens had any growth. No viral growth has been found to date. Of 13 bacterial cultures, 5 resulted in growth of coagulase-negative Staphylococcus. Of these five positive specimens, one also had growth of Corynebacterium and one had growth of Neisseria. CONCLUSION: The potential exists for operating personnel to be exposed to viable bacteria during laser resurfacing.     

Clathrin gene expression is androgen regulated in the prostate

Androgens are required for the development and function of the prostate. In a normal human prostate, androgens control the synthesis of proteins such as prostate-specific antigen and human glandular kallikrein. The prostate secretes these proteins as well as a number of other compounds to form the prostatic fluid. Using differential display PCR to detect novel androgen-regulated genes, clathrin heavy chain expression was identified as potentially being up-regulated by androgens in the prostate cancer cell line LNCaP. We report here that the clathrin heavy chain and light chain genes are regulated by androgens. Clathrin heavy chain messenger RNA was up-regulated by androgens in a concentration- and time-specific manner in the LNCaP cell line. Translation of clathrin heavy chain messenger RNA was stimulated by androgens. Steady state levels of clathrin light chains a and b were up-regulated in the presence of androgen in LNCaP cells. Clathrin gene expression was examined in normal rat prostates, and similar results were found. Clathrin heavy chain protein levels in the rat prostate are also affected by the androgen status of the animal. We hypothesize that clathrin may be involved in the exocytosis of androgen-regulated secretory proteins such as prostate-specific antigen and human glandular kallikrein.     

Optimum Windows for Carrier Frequency Estimation

The energy spectrum [X2(f)] of a ?windowed sample? of an unmodulated RF carrier will generally exhibit a peak value at or near the carrier frequency. The location of this peak is frequently used in signal analysis as an estimate of the true carrier frequency. This paper investigates the error in such estimates in cases where the signal arrives in the presence of ?broad-band? additive noise and shows that the error is due to both the added noise and spectral ?leakage? effects. Both these error mechanisms are affected by window duration and window shape. This paper proceeds further to pose two optimization criteria for the selection of a ?best window? shape for the minimization of estimation error. The two criteria are related to two differing views of prior un-certainty about the actual carrier frequency. These criteria accordingly provide different, but similar forms for the optimum window. Moreover, in worsening signal-to-noise conditions, both forms of optimum window tend to a rectangular shape.     

Singularity perturbed large-scale distributed-parameter control systems: an application to nuclear reactor control

A class of distributed-parameter control systems involving interacting fast and slow subsystems is considered and treated by an extension of the singular perturbation method well known in the field of lumped-parameter large scale systems theory. In particular, the method is applied to a power nuclear reactor with one fast, one slow and one delayed neutron group, where, due to that the velocities of fast neutrons are extremely high, a very small parameter multiplies the partial time derivative of the fast neutron flux. The method is useful for the treatment of practical nuclear reactor control problems which require the Riccati equation as an intermediate step.     

The National Ignition Facility neutron time-of-flight system and its initial performance (invited)

The National Ignition Facility (NIF) successfully completed its first inertial confinement fusion (ICF) campaign in 2009. A neutron time-of-flight (nTOF) system was part of the nuclear diagnostics used in this campaign. The nTOF technique has been used for decades on ICF facilities to infer the ion temperature of hot deuterium (D(2)) and deuterium-tritium (DT) plasmas based on the temporal Doppler broadening of the primary neutron peak. Once calibrated for absolute neutron sensitivity, the nTOF detectors can be used to measure the yield with high accuracy. The NIF nTOF system is designed to measure neutron yield and ion temperature over 11 orders of magnitude (from 10(8) to 10(19)), neutron bang time in DT implosions between 10(12) and 10(16), and to infer areal density for DT yields above 10(12). During the 2009 campaign, the three most sensitive neutron time-of-flight detectors were installed and used to measure the primary neutron yield and ion temperature from 25 high-convergence implosions using D(2) fuel. The OMEGA yield calibration of these detectors was successfully transferred to the NIF.     

A gated liquid-scintillator-based neutron detector for fast-ignitor experiments and down-scattered neutron measurements

The detection of neutrons in fast-ignitor experiments or down-scattered neutrons in inertial fusion experiments is very challenging since it requires the neutron detection system to recover within 10-100 ns from a high background orders of magnitude stronger than the signal of interest. The background is either the hard x-ray emission from short-pulse laser target interactions for the fast-ignitor experiments or the primary neutron signal for the down-scattered neutrons. A liquid-scintillator detector has been developed using a gated photomultiplier that suppresses the background signal and eliminates the afterglow present in conventional plastic scintillators.     

Image correlation microscopy for uniform illumination

Image cross-correlation microscopy is a technique that quantifies the motion of fluorescent features in an image by measuring the temporal autocorrelation function decay in a time-lapse image sequence. Image cross-correlation microscopy has traditionally employed laser-scanning microscopes because the technique emerged as an extension of laser-based fluorescence correlation spectroscopy. In this work, we show that image correlation can also be used to measure fluorescence dynamics in uniform illumination or wide-field imaging systems and we call our new approach uniform illumination image correlation microscopy. Wide-field microscopy is not only a simpler, less expensive imaging modality, but it offers the capability of greater temporal resolution over laser-scanning systems. In traditional laser-scanning image cross-correlation microscopy, lateral mobility is calculated from the temporal de-correlation of an image, where the characteristic length is the illuminating laser beam width. In wide-field microscopy, the diffusion length is defined by the feature size using the spatial autocorrelation function. Correlation function decay in time occurs as an object diffuses from its original position. We show that theoretical and simulated comparisons between Gaussian and uniform features indicate the temporal autocorrelation function depends strongly on particle size and not particle shape. In this report, we establish the relationships between the spatial autocorrelation function feature size, temporal autocorrelation function characteristic time and the diffusion coefficient for uniform illumination image correlation microscopy using analytical, Monte Carlo and experimental validation with particle tracking algorithms. Additionally, we demonstrate uniform illumination image correlation microscopy analysis of adhesion molecule domain aggregation and diffusion on the surface of human neutrophils.