Novel burn device for rapid, reproducible burn wound generation.

INTRODUCTION: Scarring following full thickness burns leads to significant reductions in range of motion and quality of life for burn patients. To effectively study scar development and the efficacy of anti-scarring treatments in a large animal model (female red Duroc pigs), reproducible, uniform, full-thickness, burn wounds are needed to reduce variability in observed results that occur with burn depth. Prior studies have proposed that initial temperature of the burner, contact time with skin, thermal capacity of burner material, and the amount of pressure applied to the skin need to be strictly controlled to ensure reproducibility. The purpose of this study was to develop a new burner that enables temperature and pressure to be digitally controlled and monitored in real-time throughout burn wound creation and compare it to a standard burn device. METHODS: A custom burn device was manufactured with an electrically heated burn stylus and a temperature control feedback loop via an electronic microstat. Pressure monitoring was controlled by incorporation of a digital scale into the device, which measured downward force. The standard device was comprised of a heat resistant handle with a long rod connected to the burn stylus, which was heated using a hot plate. To quantify skin surface temperature and internal stylus temperature as a function of contact time, the burners were heated to the target temperature (200±5°C) and pressed into the skin for 40s to create the thermal injuries. Time to reach target temperature and elapsed time between burns were recorded. In addition, each unit was evaluated for reproducibility within and across three independent users by generating burn wounds at contact times spanning from 5 to 40s at a constant pressure and at pressures of 1 or 3lbs with a constant contact time of 40s. Biopsies were collected for histological analysis and burn depth quantification using digital image analysis (ImageJ). RESULTS: The custom burn device maintained both its internal temperature and the skin surface temperature near target temperature throughout contact time. In contrast, the standard burner required more than 20s of contact time to raise the skin surface temperature to target due to its quickly decreasing internal temperature. The custom burner was able to create four consecutive burns in less than half the time of the standard burner. Average burn depth scaled positively with time and pressure in both burn units. However, the distribution of burn depth within each time-pressure combination in the custom device was significantly smaller than with the standard device and independent of user. CONCLUSIONS: The custom burn device's ability to continually heat the burn stylus and actively control pressure and temperature allowed for more rapid and reproducible burn wounds. Burns of tailored and repeatable depths, independent of user, provide a platform for the study of anti-scar and other wound healing therapies without the added variable of non-uniform starting injury.

The landing of the NEAR-Shoemaker spacecraft on asteroid 433 Eros.

The NEAR-Shoemaker spacecraft was designed to provide a comprehensive characterization of the S-type asteroid 433 Eros (refs 1,2,3), an irregularly shaped body with approximate dimensions of 34 x 13 x 13 km. Following the completion of its year-long investigation, the mission was terminated with a controlled descent to its surface, in order to provide extremely high resolution images. Here we report the results of the descent on 12 February 2001, during which 70 images were obtained. The landing area is marked by a paucity of small craters and an abundance of 'ejecta blocks'. The properties and distribution of ejecta blocks are discussed in a companion paper. The last sequence of images reveals a transition from the blocky surface to a smooth area, which we interpret as a 'pond'. Properties of the 'ponds' are discussed in a second companion paper. The closest image, from an altitude of 129 m, shows the interior of a 100-m-diameter crater at 1-cm resolution.

Imaging of small-scale features on 433 Eros from NEAR: evidence for a complex regolith.

On 25 October 2000, the Near Earth Asteroid Rendevous (NEAR)-Shoemaker spacecraft executed a low-altitude flyover of asteroid 433 Eros, making it possible to image the surface at a resolution of about 1 meter per pixel. The images reveal an evolved surface distinguished by an abundance of ejecta blocks, a dearth of small craters, and smooth material infilling some topographic lows. The subdued appearance of craters of different diameters and the variety of blocks and different degrees of their burial suggest that ejecta from several impact events blanketed the region imaged at closest approach and led to the building up of a substantial and complex regolith consisting of fine materials and abundant meter-sized blocks.

NEAR at eros: imaging and spectral results

Eros is a very elongated (34 kilometers by 11 kilometers by 11 kilometers) asteroid, most of the surface of which is saturated with craters smaller than 1 kilometer in diameter. The largest crater is 5.5 kilometers across, but there is a 10-kilometer saddle-like depression with attributes of a large degraded crater. Surface lineations, both grooves and ridges, are prominent on Eros; some probably exploit planes of weakness produced by collisions on Eros and/or its parent body. Ejecta blocks (30 to 100 meters across) are abundant but not uniformly distributed over the surface. Albedo variations are restricted to the inner walls of certain craters and may be related to downslope movement of regolith. On scales of 200 meters to 1 kilometer, Eros is more bland in terms of color variations than Gaspra or Ida. Spectra (800 to 2500 nanometers) are consistent with an ordinary chondrite composition for which the measured mean density of 2.67 +/- 0.1 grams per cubic centimeter implies internal porosities ranging from about 10 to 30 percent.

Sublethal copper toxicity and food response in the freshwater crayfish Cambarus bartonii (Cambaridae, Decapoda, Crustacea).

Food response preceding and following exposure to Cu concentrations of 0.00, 0.02, and 0.2 mg/L was observed in male and female Cambarus bartonii from an uncontaminated, freshwater lake. The animals were tested in a Y-maze. Control animals demonstrated food localization, and the treated animals, either no localization or slight food avoidance. The latency for localization in the Cu-exposed males increased. Females revealed slight increases in latency. There were no significant differences between the low and the high Cu concentration groups in food detection or latency. However, there was an increase in mortality in the higher concentration group and significant difference in mortality among three copper concentrations (P<0.02). Females seem to recover from Cu-induced impairment slightly faster than males, suggesting a more efficient mechanism for detoxifying copper. Female mortality, however, remained equally high in the high Cu concentration group. The toxic effects of copper persist after removal of the toxicant and occur at concentrations much lower than reported lethal levels.

Imaging of asteroid 433 eros during NEAR's flyby reconnaissance

During the 23 December 1998 flyby of asteroid 433 Eros, the Near-Earth Asteroid Rendezvous (NEAR) spacecraft obtained 222 images of Eros, as well as supporting spectral observations. The images cover slightly more than two-thirds of Eros (best resolution is approximately 400 meters per pixel) and reveal an elongated, cratered body with a linear feature extending for at least 20 kilometers. Our observations show that Eros has dimensions of 33 x 13 x 13 kilometers. The volume, combined with the mass determined by the NEAR radio science experiment, leads to a density of 2.5 +/- 0.8 grams per cubic centimeter. This relatively high density, and the presence of an extensive linear feature, suggest that Eros may be a structurally coherent body.

Genomic mapping of a calicivirus VPg.

We identified a primate calicivirus (Pan-1) VPg in Pan-1-infected cells. The Pan-1 VPg was associated with both genomic and subgenomic RNAs. RNase digestion of Pan-1 RNA yielded a residual protein of 16 kDa. The N-terminal sequence of Pan-1 VPg was determined by direct amino acid sequencing and mapped to a region of the genome equivalent to picornavirus VPgs. Alignment of this protein sequence with similar regions of other calicivirus genomes allowed identification of conserved amino acid motifs and potential boundaries of the calicivirus VPg genes. Proteinase K treatment abolished the infectivity of Pan-1 RNA, suggesting that Pan-1 VPg is required for RNA infectivity.

Receiver operating characteristic analysis for biliary complications in liver transplantation.

Receiver operating characteristic (ROC) analysis was used to assess the use of the serum chemical markers, gamma-glutamyl transferase (GGT), alkaline phosphatase (AP), and total bilirubin (BR) as tests for biliary complications in patients who had undergone orthotopic liver transplantation. Our study consisted of 105 consecutive adult transplant patients at the University of Chicago from March 1985 to November 1988. Biliary complications were determined by cholangiogram. Maximum serum values for three postoperative time periods (days 0 to 30, days 31 to 90, and > 90 days) were obtained for each patient. ROC analysis showed that GGT was the best single test during the earliest and latest time periods, whereas BR was best during days 31 through 90. We also assessed the time periods, surgical biliary anastomosis, pretransplant diagnosis, and location of biliary lesions compared with the incidence of biliary pathology for the patients. We found that patients with a pretransplant diagnosis of acute parenchymal liver disease were more likely to have biliary complications, and patients with end-to-end anastomosis with T tube were also more likely to have biliary complications. We further conclude that GGT, BR, and AP are all useful in screening for biliary complications and should be used routinely in liver transplant patients.

Slow brain potentials in a visual-spatial memory task: topographic distribution and inter-laboratory consistency.

Slow brain electrical potentials (SPs) were investigated in a visual-spatialmemory task. Two issues were addressed: (1) the nature and topographic distribution of the potentials obtained under such conditions; and (2) the consistency of the SPs when recorded in six identically configured laboratories. Fifteen young male subjects were studied at each laboratory (total n = 90). The paradigm entailed presentations of paired-visual patterns (S1 and S2), to which subjects responded with a choice reaction time response indicating whether or not the two patterns matched. A biphasic contingent negative variation (CNV) was produced which consisted of an early symmetric component with bilateral foci at posterior temporal sites and a subsequent mid-parietal dominant wave later in the retention interval. Although the CNVs from all laboratories were similar in waveform and in topographic distribution, there were significant inter-laboratory differences in amplitude of the slow potential components. The topographic distributions of the components and the possible role of sampling effects are discussed.

Different aggressive behaviours are exaggerated by facing vs. broadside subliminal stimuli shown to socially isolated Siamese fighting fish, Betta splendens.

We report and analyse some features of a new phenomenon: socially isolated Betta splendens become extremely hyper-aggressive after seeing brief glimpses of fish models or mirrors. These brief glimpses are below the threshold for releasing aggressive display, so they are considered subliminal aggressive stimuli. The hyper-aggressiveness was observed to last for weeks. To confirm that hyper-aggressiveness was dependent upon the aggressive significance of the subliminal stimuli, we presented socially isolated Betta splendens with subliminal models in either a `facing' posture (used mainly in aggressive contexts), or a `broadside' posture (used in many social contexts). The fish shown the aggressive `facing' subliminal stimuli became more aggressive, while those shown `broadside' stimuli performed more generalized advertisement behaviours. The display posture of the model, which may incorporate specific features relevant to aggression, therefore determined how the subliminal aggressive stimuli altered subsequent aggressiveness. This difference was also persistent. Subliminal stimuli may thus be implicated in the hyper-aggressiveness so often reported after social isolation.

Cognitive difficulty of a peripherally presented visual task affects head movements during gaze displacement.

The maintenance and adjustment of visual gaze are functions both of eye and of head movement. Compared to the factors that affect eye movement during gaze displacement, the factors that affect head movement have received relatively little attention. Most experimenters have restricted head movements to determine how the eye acquires information. Information is commonly acquired without head movements (e.g., it is likely you are moving your eyes without moving your head as you read the words on this page). However, when visual information beyond the written page is acquired head movements in addition to eye movements are likely to occur. The purpose of this experiment was to study gaze displacement under more natural conditions in which the eyes and head were both free to move. Specifically, the purpose of this experiment was to identify the pattern of gaze displacement as a function of cognitive task difficulty. Visual information was presented at an eccentricity of 40 degrees of visual angle either to the left or to the right of a center fixation point (0 degree eccentricity) to 24 undergraduate subjects (12 male). On each trial, five integers were presented in rapid succession; subjects were asked to count the number of odd integers or to arithmetically manipulate the integers. When subjects expected to perform the more difficult task of arithmetic manipulation, they were more likely to make head movements in the direction of the stimuli, F1,16 = 9.34, P < 0.05. Those subjects who made head movements to acquire the peripherally presented visual information made significantly more errors than the 'non-movers', F1,24 = 6.03, P < 0.05. These results suggest subjects who moved their head to acquire peripheral information may have found the task to be more difficult than subjects who did not make head movements. The results confirm that head movements play a critical role in the intake of information even in structured laboratory tasks and suggest the common method of restricting head movements to study eye movements may not be a natural method of information intake.

Application of photoelectron spectromicroscopy to a systematic study of toxic and natural elements in neurons.

A systematic photoelectron spectromicroscopy study is presented of the spatial distribution of a toxic element, aluminium, iron or chromium, in neuron cultures, after exposure to a solution of the element. The study was performed by the X-ray secondary-emission microscopy (XSEM) version of photoelectron Spectromicroscopy. The distribution of the elements was investigated with two complementary approaches: digital subtraction imaging and individual X-ray absorption spectra from microscopic areas. The results coherently indicate different localization patterns for different elements, and, in particular, extreme localization of aluminium to a few rare cells identifiable as Purkinje neurons. In the case of iron-exposed specimens, the distribution analysis was extended to naturally present phosphorus, and used to estimate the XSEM sensitivity.

Dose-related effects of alcohol on dynamic posturography and oculomotor measures.

Four healthy male volunteers < 30 years of age participated in a blinded study of placebo versus low (0.45 g/kg lean body weight = LBW), medium (0.80 g/kg LBW) and high (1.05 g/kg LBW) dose ethanol ingestion to investigate its effect upon gaze and posture control. Serial electronystagmography and computerized platform posturography were performed at different points along each subject's blood alcohol concentration (BAC) curve as measured by breath analysis. Smooth pursuit and positional testing revealed subtle abnormalities at sub-intoxicating BACs. In addition, instability on posturography was evident on the Sensory Organization Test with no statistically significant influence observed on muscle latency testing as determined by sway analysis. We conclude that even low ethanol BAC levels produce widespread gaze and posture control effects which can be easily documented.

Clinical experience with a new lead combining active fixation with steroid elution.

The Medtronic lead engineering model number 10335A represents a new concept in lead design combining active fixation with steroid elution. It aims for immediate stability and low chronic thresholds. Twenty-one leads, 9 atrial and 12 ventricular, were implanted in 13 patients (10 males, mean age 68; range 22-91 years). The atrial leads showed no rise in pulse width threshold at a voltage of 1.6 volts (mean thresholds at implant, 1, and 26 weeks; 0.1 +/- 0.09 msec, 0.15 +/- 0.04 msec, and 0.1 +/- 0.03 msec, respectively). The ventricular leads had a small but significant rise between implant and 1 week at an output of 1.6 volts (0.07 +/- 0.03 msec increasing to 0.11 +/- 0.04 msec; P < 0.02) but no significant later rise (0.1 +/- 0.04 msec at 2 weeks and 0.1 +/- 0.05 msec at 6 months). These low chronic thresholds would allow early reprogramming of the unit to low voltages resulting in a battery saving with prolongation of the unit's life. There were no significant changes in the P and R wave amplitudes, but there was a fall in lead impedance in the ventricular leads between implantation and 1 week (P < 0.02) but none subsequently, and there was no significant change in atrial impedance. There were no sensing failures and no lead displacements. Despite impressive pacing characteristics, the study was suspended because of a high level of mechanical complications. Of the 96 patients implanted worldwide with 136 leads there were eight helix deformations, which will require redesign.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminium in rat cerebellar primary cultures: glial cells and GABAergic neurones.

Experimental evidence of the preferential uptake of aluminium by GABAergic neurones and glial cells was provided by synchrotron spectromicroscopy studies. We observed rat cerebellar cultures enriched for GABAergic neurones or glial cells exposed to aluminium ions, detecting the presence and identifying the chemical status of aluminium on cell structures.

A nurse-managed inpatient program for patients with chronic mental disorders.

The deinstitutionalization movement has left a legacy of need for appropriate care for inpatients with chronic refractory mental illness. This article describes a nurse managed program for such patients based on the principles of a therapeutic milieu. The program was formally defined for a 6-month period with an effort to include outcome measures for program evaluation. Multidisciplinary treatment team planning with a psychiatric nursing clinical specialist as team leader provided a format for putting therapeutic concepts into practice. The nurse clinical specialist and two nurse practitioners served as case managers as well as primary care providers. Program evaluation showed that cost-effective quality care could be achieved with a reduction in polypharmacy and overall neuroleptic usage. The notion of a restraint appropriate environment, with the goal of minimizing restraint use, was introduced and put into practice.