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81.
82.
PURPOSE: Two experiments explored the extent to which induced blur, reduced luminance, and reduced visual fields affect drivers' steering performance in a driving simulator. METHODS: In experiment 1, ten young participants (M = 21.2 years) drove at approximately 89 km/h (55 mph) along a curvy roadway while being exposed to blur (0 to + 10 D), luminance (0.003 to 16.7 cd/m), and visual field (1.7 and 150 degrees) manipulations. In experiment 2, a new group of ten young participants (M = 18.5 years) drove while exposed to seven visual field sizes (1.7 to 150 degrees). RESULTS: Steering was sensitive to a reduced field size but not to the blur and luminance challenges. Acuity, on the other hand, was sensitive to the blur and luminance challenges but not to reduced field size. DISCUSSION: In healthy young drivers, steering performance is remarkably robust to severe blur and to extremely low luminances. These results support a key element of the selective degradation hypothesis advanced by Leibowitz and colleagues--that steering abilities are preserved at night even when the ability to recognize objects and hazards is not. Additional research should address the other element of this hypothesis--that drivers fail to appreciate the extent to which their visual abilities are degraded at night. 相似文献
83.
Effects of pegfilgrastim on normal biodistribution of 18F-FDG: preclinical and clinical studies. 总被引:1,自引:0,他引:1
Heather A Jacene Takayoshi Ishimori James M Engles Sophie Leboulleux Vered Stearns Richard L Wahl 《Journal of nuclear medicine》2006,47(6):950-956
The purpose of this study was to evaluate the effects of pegfilgrastim, a long-acting granulocyte colony-stimulating factor, on the normal biodistribution of (18)F-FDG in an animal model and in humans. METHODS: Two groups of 12 rats received a single subcutaneous injection of either normal saline or pegfilgrastim. One, 7, 14, and 21 d after injection, biodistribution studies were performed 1 h after (18)F-FDG injection. Sixteen breast cancer patients underwent baseline (18)F-FDG PET/CT and, approximately 1 wk after receiving 1 dose of docetaxel and adjunctive pegfilgrastim, follow-up (18)F-FDG PET/CT (scan 2). Standardized uptake values corrected for lean body mass (SUL) were determined for several normal organs before and after therapy. RESULTS: In rats, bone marrow (18)F-FDG uptake (standardized uptake value) was higher in the pegfilgrastim group 1 d after injection (mean +/- SD, 8.3 +/- 4.1 vs. 2.5 +/- 0.2, P < 0.05), whereas (18)F-FDG uptake in blood was lower (0.41 +/- 0.06 vs. 0.49 +/- 0.01, P < 0.05). In patients, mean SUL was higher in bone marrow (4.49 +/- 1.50 vs. 1.33 +/- 0.22, P < 0.0001), spleen (3.29 +/- 0.83 vs. 1.23 +/- 0.23, P < 0.0001), and liver (1.45 +/- 0.25 vs. 1.31 +/- 0.23, P = 0.01) but lower in brain (4.18 +/- 0.76 vs. 5.14 +/- 1.44, P < 0.01) on scan 2 than on the baseline scan. CONCLUSION: In both the animal model and humans, pegfilgrastim markedly increased bone marrow uptake of (18)F-FDG and reduced (18)F-FDG uptake in some normal tissues. These profound alterations in (18)F-FDG biodistribution induced by pegfilgrastim must be considered when one is evaluating quantitative (18)F-FDG PET scans for tumor response to therapy. 相似文献
84.
Summary The olfactory epithelium of the adult hamster (Mesocricetus auratus) was examined with the scanning electron microscope following olfactory nerve axotomy. Axotomy results in retrograde degeneration of mature olfactory neurons. Maximum degeneration was observed around day 4. During the degeneration period the epithelium consists primarily of supporting and basal cells. Microvillar columnar supporting cells were observed to have fine cellular processes extending from their lateral border to neighbouring cells. Supporting cells extended to the basal lamina where they terminated in foot-like processes of variable shapes (club, splay and hook). Basal cells which gave rise to new replacement olfactory neurons were observed near the basal lamina. They had a rough cellular surface covered with small granules and fine cellular extensions. Bowman's gland duct cells extended unbranched through the epithelium where they formed funnel duct openings covered with microvilli. During early recovery periods (5–30 days) the number of olfactory neurons in the lower epithelium region increased. We observed olfactory neurons with developing axon and dendritic processes. Specialized growth cone structures were seen at the tips. Olfactory neuron growth cones were elongated or club-shaped and had a ruffled membrane surface. Several thin filopodia extended from the growth cone and made contact with adjacent cells. At late recovery periods (35–120 days) there was a marked increase in the number of olfactory neurons within the middle and lower epithelium regions. Numerous dendritic processes extended to the epithelial surface and terminated in knob-like ciliated structures. Olfactory axons passed basally, forming small intra-epithelial bundles that penetrated the basal lamina then fasciculated into larger bundles within the lamina propria.This study provides detailed three-dimensional observations of the olfactory epithelium following neuron injury, and describes neural degenerative changes, replacement of olfactory neurons, development and maturation. In addition, we describe the structure and basal attachment of supporting cells and their glial-like relation with olfactory neurons. 相似文献
85.
J H Newcorn J M Halperin J M Healey J D O'Brien D M Pascualvaca L E Wolf A Morganstein V Sharma J G Young 《Journal of the American Academy of Child and Adolescent Psychiatry》1989,28(5):734-738
To assess the relationship between the DSM-III criteria for attention deficit disorder with hyperactivity (ADDH) and the DSM-III-R criteria for attention-deficit hyperactivity disorder (ADHD), children from an inner city parochial school were evaluated using a 30-item teacher questionnaire consisting of the DMS-III and DSM-III-R criteria for these disorders, the revised Conners Parent and Teacher Questionnaires, and a continuous performance test. Diagnostic groups were established based on teacher ratings of the DSM items and evaluated in relation to the rating scale data and continuous performance test. While children who were identified by teachers as having ADDH almost always satisfied the criteria for ADHD, a new group of children who were hyperactive and impulsive but less clearly inattentive also met the criteria for ADHD. Implications of the change in diagnostic criteria are discussed. 相似文献
86.
87.
88.
Henry Cisneros 《AIDS and behavior》2007,11(2):7-8
For persons battling HIV/AIDS a stable place to live may decide the length and quality of life itself. It is nearly impossible for a person on the streets to engage in a needed continuous AIDS treatment regimen when the very basic question of where that person will rest his or her head when darkness comes in just a few hours is unresolved. When danger lurks on the streets, when cold numbs the limbs, when tiredness overwhelms the mind, when fear breaks the spirit, a place to call home would make all the difference. 相似文献
89.
During much of the past century, the microbe itself stood at the heart of microbial pathogenesis. Little thought was devoted
to the host per se, though it was granted that differences in susceptibility to certain infections did exist between individuals,
and between different ethnic groups. During the past 20 years, extraordinary strides in our grasp of mammalian genetics have
made the host side of the equation far more approachable. A restricted collection of genes now presents itself as the likely
repository for genetic differences that foretell susceptibility to infectious disease. The Toll-like receptors, of which 10
are presently known to exist in humans, offer an excellent example of this genetic reductionism, in that they embody the afferent
component of the innate immune system, and strongly influence the containment of an infection from its earliest stages. The
Toll-like receptors were identified as the culmination of a long and relentless inquiry into the yet-unsolved clinical problem
of sepsis. 相似文献
90.