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DESIGN: Prospective laboratory methodology study. PURPOSE: Certain tissues, by virtue of their shape and extreme thinness or pliability, are difficult to position correctly during routine paraffin embedding to provide the optimal ...
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DESIGN: Prospective laboratory methodology study. PURPOSE: Certain tissues, by virtue of their shape and extreme thinness or pliability, are difficult to position correctly during routine paraffin embedding to provide the optimal orientation for histopathologic studies. Biopsy specimens from temporal arteries must be sampled at different points along the length of the artery. Other tissues such as subfoveal neovascular membranes and fragments of lens capsule lack the thickness and rigidity to be positioned on edge to yield cross-sectional views. The authors' technique improves the orientation and thereby maximizes the histologic information obtained from such specimens. METHODS AND MATERIALS: From January 1, 1990, to April 30, 1999, the authors studied 500 consecutive temporal artery biopsy specimens and 200 successive subfoveal neovascular membranes. RESULTS: Cutting a 20-mm cylindrical fragment of temporal artery at 1- to 1.5-mm intervals yielded approximately 13 to 20 cross-sections along the length of the artery. When the specimens were positioned together and embedded in agar, the pathologist could easily study multiple cross-sections of the artery. Additionally, using the agar technique, the authors were able to obtain cross-sections of other specimens submitted, such as subfoveal neovascular membranes, and studied each of the different layers to evaluate the disease process. By the same method, the authors placed small fragments of lens capsule with underlying cortex on edge and readily identified short, gram-positive coccobacilli consistent with Propionibacterium acnes endophthalmitis. CONCLUSION: The agar technique can greatly improve the quality of diagnostic information gleaned from temporal artery biopsy specimens and other small tissue samples.
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PURPOSE: To critically evaluate the following clinical wisdom regarding custom (wavefront-guided) laser in situ keratomileusis (LASIK) that subjects with better-than-average best-corrected visual acuity (BCVA) before surgery have ...
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PURPOSE: To critically evaluate the following clinical wisdom regarding custom (wavefront-guided) laser in situ keratomileusis (LASIK) that subjects with better-than-average best-corrected visual acuity (BCVA) before surgery have a greater risk of losing BCVA postoperatively than do subjects with worse-than-average BCVA before surgery. METHODS: High contrast BCVA was measured once before and 3 months after custom LASIK in one eye of 79 subjects. Preoperative spherical equivalent refractive error ranged between -1.00 and -10.38 D. The sample was divided into one of two subsamples: eyes that had better-than-average preoperative BCVA (<-0.11 logMAR) and eyes that had average or worse-than-average preoperative BCVA (>/=-0.11 logMAR). Controls were implemented for retinal magnification and for the statistical phenomenon of regression to the mean of the preoperative acuity measurement. RESULTS: On average, for the entire sample, moving the correction from the spectacle plane to the corneal plane increased letter acuity 4.7% (1 letter, 0.02 logMAR). For each subsample, the percentage regression to the mean was 57.24%. After correcting for magnification effects and regression to the mean, eyes with better-than-average preoperative acuity had a small but significant gain in acuity ( approximately 1 letter, p = 0.040) that was nearly identical to the gain for eyes with worse-than-average preoperative acuity ( approximately 1.5 letters, p = 0.002). CONCLUSIONS: Custom LASIK produced a statistically significant gain in visual acuity after correction for magnification effects. Dividing the sample into two subsamples based on preoperative acuity confirmed the common clinical observation that eyes with better-than-average acuity tend to remain the same or lose acuity, whereas eyes with worse-than-average acuity tend to gain acuity. However, when only one acuity measurement is taken at a single time point and the sample is subsampled nonrandomly, this clinical observation is due to a statistical artifact (regression to the mean) and is not attributable to the surgery.
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This study investigates the self-reported levels of occupational burnout among 1,094 U.S. Air Force drone operators stationed within the borders of the United States who are supporting a wide range of around-the-clock military sur...
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This study investigates the self-reported levels of occupational burnout among 1,094 U.S. Air Force drone operators stationed within the borders of the United States who are supporting a wide range of around-the-clock military surveillance and weapons strike missions across the globe. Data were gathered from a Web-based survey of demographic items and the Maslach Burnout Inventory assessing the facets of occupational burnout (exhaustion, cynicism, and professional efficacy). The overall survey response rate was 49%. Approximately 20% reported high levels of exhaustion, and 11% reported high levels of cynicism, but only 3% reported low levels of professional efficacy. Predictors of exhaustion, as well as between group differences, were identified along with recommendations for performance improvement and mitigating risks to safety.
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BACKGROUND: The USAF devotes great financial and medical assets to the identification and evaluation of USAF aircrew who have been grounded from flying duties for medical conditions thought to be dangerous to the flying mission or...
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BACKGROUND: The USAF devotes great financial and medical assets to the identification and evaluation of USAF aircrew who have been grounded from flying duties for medical conditions thought to be dangerous to the flying mission or personal safety. The purpose of this study is to update the literature and to demonstrate that USAF efforts during the past 19 yr have improved our ability to retain experienced aviators. METHODS: The USAF waiver file was reviewed to quantify the number of USAF pilots and navigators receiving permanent medical disqualifications from flying duties during 1995-1999. We identified 157 cases, which were stratified by age group and sex. RESULTS: The number of disqualifications increased incrementally by age group. The most common diagnoses resulting in permanent disqualification were coronary artery disease, hypertension, back pain and disk abnormalities, migraine headaches, diabetes mellitus, and substance/alcohol abuse. DISCUSSION: These results are very similar to those reported in a 1984 USAF study and other studies of aviation populations. The rate of permanent flying disqualifications in this study was equal to 0.18% per year compared to 4.1% per year in 1984. This decrease in the rate of disqualifications could be due to modification of USAF standards, utilization of clinical management groups, better screening of applicants, new technology or therapies, and effective preventive medicine efforts throughout the Air Force.
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Potential bio-behavioral effects of infrasonic energy (< 20 Hz) have generally been considered to be due to extra-aural (non-hearing) mechanisms. Since systems that deliver acoustic energy, including infrasound, are being considered for use as non-lethal weapons, it is important to elucidate the possible aural and extra-aural effects of such energy. Methods: Subjects (5 adult male rhesus monkeys) engaged in a continuous compensatory tracking task. The effect of short-term exposure to high-intensity infrasound (160 dB), using a custom-made system, on tracking task performance was measured. The effects of the infrasound exposure on auditory measures (otoacoustic emissions and auditory brainstem evoked potentials) were also examined. Results: Tracking behavior of the subjects was substantially disrupted by exposure to 10Hz infrasound at 160 dB. There was no evidence of any post-exposure alterations in tympanometry, distortion product otoacoustic emissions, or in auditory brainstem evoked potentials.Conclusions: Although the present experiments showed significant effects on performance, further experiments using larger working volumes would have to be undertaken to address the potential uses of such a device....
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Potential bio-behavioral effects of infrasonic energy (< 20 Hz) have generally been considered to be due to extra-aural (non-hearing) mechanisms. Since systems that deliver acoustic energy, including infrasound, are being considered for use as non-lethal weapons, it is important to elucidate the possible aural and extra-aural effects of such energy. Methods: Subjects (5 adult male rhesus monkeys) engaged in a continuous compensatory tracking task. The effect of short-term exposure to high-intensity infrasound (160 dB), using a custom-made system, on tracking task performance was measured. The effects of the infrasound exposure on auditory measures (otoacoustic emissions and auditory brainstem evoked potentials) were also examined. Results: Tracking behavior of the subjects was substantially disrupted by exposure to 10Hz infrasound at 160 dB. There was no evidence of any post-exposure alterations in tympanometry, distortion product otoacoustic emissions, or in auditory brainstem evoked potentials.Conclusions: Although the present experiments showed significant effects on performance, further experiments using larger working volumes would have to be undertaken to address the potential uses of such a device.
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The Department of Defense (DoD) Global Laboratory-Based Influenza Surveillance Program was initiated in 1997 to formally consolidate and expand existing influenza surveillance programs within the DoD and in areas where DoD was wor...
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The Department of Defense (DoD) Global Laboratory-Based Influenza Surveillance Program was initiated in 1997 to formally consolidate and expand existing influenza surveillance programs within the DoD and in areas where DoD was working. Substantial changes in 2008 provided an opportunity to review the operation of the surveillance program as it existed during seven complete influenza seasons (1998-2005); the review was conducted in 2008. A unique aspect of the DoD program was the global reach for specimen collection and the ability to rapidly ship, process, and evaluate specimens from 27 countries. The resulting epidemiologic data combined with the culture results from >46,000 patients provided information that was shared with similar national and international programs, such as those of the CDC. Likewise, selected influenza isolates were molecularly characterized and shared with the CDC to be compared with other surveillance programs. Timeliness of the samples contributed to the information available for annual influenza vaccine selection.
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The Department of Defense (DoD) Global Laboratory-Based Influenza Surveillance Program was initiated in 1997 to formally consolidate and expand existing influenza surveillance programs within the DoD and in areas where DoD was wor...
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The Department of Defense (DoD) Global Laboratory-Based Influenza Surveillance Program was initiated in 1997 to formally consolidate and expand existing influenza surveillance programs within the DoD and in areas where DoD was working. Substantial changes in 2008 provided an opportunity to review the operation of the surveillance program as it existed during seven complete influenza seasons (1998-2005); the review was conducted in 2008. A unique aspect of the DoD program was the global reach for specimen collection and the ability to rapidly ship, process, and evaluate specimens from 27 countries. The resulting epidemiologic data combined with the culture results from >46,000 patients provided information that was shared with similar national and international programs, such as those of the CDC. Likewise, selected influenza isolates were molecularly characterized and shared with the CDC to be compared with other surveillance programs. Timeliness of the samples contributed to the information available for annual influenza vaccine selection.
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Background: Potential bio-behavioral effects of infrasonic energy (< 20 Hz)have generally been considered to be due to extra-aural (non-hearing)mechanisms. Since systems that deliver acoustic energy, including infrasound,are being considered for use as non-lethal weapons, it is important to elucidatethe possible aural and extra-aural effects of such energy. Methods: Subjects (5adult male rhesus monkeys) engaged in a continuous compensatory trackingtask. The effect of short-term exposure to high-intensity infrasound (160 dB),using a custom-made system, on tracking task performance was measured. Theeffects of the infrasound exposure on auditory measures (otoacoustic emissionsand auditory brainstem evoked potentials) were also examined. Results:Tracking behavior of the subjects was substantially disrupted by exposure to 10-Hz infrasound at 160 dB. There was no evidence of any post-exposurealterations in tympanometry, distortion product otoacoustic emissions, or inauditory brainstem evoked potentials. Conclusions: Although the presentexperiments showed significant effects on performance, further experimentsusing larger working volumes would have to be undertaken to address thepotential uses of such a device....
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Background: Potential bio-behavioral effects of infrasonic energy (< 20 Hz)have generally been considered to be due to extra-aural (non-hearing)mechanisms. Since systems that deliver acoustic energy, including infrasound,are being considered for use as non-lethal weapons, it is important to elucidatethe possible aural and extra-aural effects of such energy. Methods: Subjects (5adult male rhesus monkeys) engaged in a continuous compensatory trackingtask. The effect of short-term exposure to high-intensity infrasound (160 dB),using a custom-made system, on tracking task performance was measured. Theeffects of the infrasound exposure on auditory measures (otoacoustic emissionsand auditory brainstem evoked potentials) were also examined. Results:Tracking behavior of the subjects was substantially disrupted by exposure to 10-Hz infrasound at 160 dB. There was no evidence of any post-exposurealterations in tympanometry, distortion product otoacoustic emissions, or inauditory brainstem evoked potentials. Conclusions: Although the presentexperiments showed significant effects on performance, further experimentsusing larger working volumes would have to be undertaken to address thepotential uses of such a device.
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Malaria in the Americas is a reemerging health issue. In 1969, the World Health Organization shifted policy from malaria eradication to malaria control. With this shift, vector control (house spraying with dichlorodiphenyltrichlor...
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Malaria in the Americas is a reemerging health issue. In 1969, the World Health Organization shifted policy from malaria eradication to malaria control. With this shift, vector control (house spraying with dichlorodiphenyltrichloroethane [DDT]) was deemphasized. Since that time, house spray rates have decreased and malaria rates have increased. Using malaria data collected since 1959 by the Pan American Health Organization, this relationship was examined with an ecological regression model. Malaria control was found to be a function of policy, disease burden, and vector control (R2 = 0.75, p < 0.001). Policy must address both disease burden and vector control. Treatment of disease burden is unquestioned; however, vector control is debated. An argument for the judicious and enlightened resumption of house spraying with DDT is presented.
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