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991.
992.
Stress and modal analyses are performed on an ultrasonic vibration system by means of a 3-dimensional finite element computation and dynamic modal analysis code "Algor" The system consists of an edge-cracked specimen linked elastically with one or two amplifying horns which come into resonant longitudinal vibration at 20kHz.Operating principle of the ultrasonic fatigue machines and experimental procedures for ultrasonic fatigue crack growth studies are briefly presented. 相似文献
993.
C Migliaccio A Nishio J Van de Water AA Ansari PS Leung Y Nakanuma RL Coppel ME Gershwin 《Canadian Metallurgical Quarterly》1998,161(10):5157-5163
Primary biliary cirrhosis (PBC) is an autoimmune liver disease characterized by the presence of antimitochondrial Abs (AMA). The autoantigens recognized by AMA are the E2 components of the pyruvate dehydrogenase complex (PDC-E2), the branched chain 2-oxoacid dehydrogenase complex E (BCOADC-E2), and the 2-oxoglutarate dehydrogenase complex E (OGDC-E2). Previous studies using murine monoclonal and human combinatorial Abs to PDC-E2 have demonstrated an intense linear staining pattern in the apical region of biliary epithelial cells (BEC) in PBC but not control liver. We therefore examined whether mAbs to the other mitochondrial autoantigens BCOADC-E2 and OGDC-E2 demonstrated disease-specific patterns of reactivity. Using an expressed recombinant "trihybrid" protein containing the lipoyl domains of PDC-E2, OGDC-E2, and BCOADC-E2, we immunized BALB/c mice to produce 35 mAbs specific for one or more of the above mitochondrial autoantigens. Seven of these mAbs uniquely stained the apical region of BEC in PBC. Of these seven, one was reactive to PDC-E2, two recognized BCOADC-E2, three were reactive to OGDC-E2, and one recognized all three Ags. Our current data demonstrate that, similar to our previous studies regarding PDC-E2, mAbs to BCOADC-E2 and OGDC-E2, or a molecule that cross-reacts with the inner lipoyl domain of all three enzymes, also show a uniquely intense staining pattern in the apical region of BEC in patients with PBC when compared with diseased controls. The abundance of such disease-specific determinants in the target cells of PBC raises interesting possibilities regarding the role of these autoantigens in the pathogenesis of this disease. 相似文献
994.
KJ Haley ME Sunday BR Wiggs HP Kozakewich JJ Reilly SJ Mentzer DJ Sugarbaker CM Doerschuk JM Drazen 《Canadian Metallurgical Quarterly》1998,158(2):565-572
Asthmatic airways are infiltrated with inflammatory cells that release mediators and cytokines into the microenvironment. In this study, we evaluated the distribution of CD45-positive leukocytes and eosinophils in lung tissue from five patients who died with severe asthma compared with five patients with cystic fibrosis. For morphometric analysis, the airway wall was partitioned into an "inner" area (between basement membrane and smooth muscle) and an "outer" area (between smooth muscle and alveolar attachments). Large airways (with a perimeter greater than 3.0 mm) from patients with asthma or cystic fibrosis had a greater density of CD45-positive cells (p < 0.05) and eosinophils (p < 0.001) in the inner airway region compared with the same airway region in small airways. Furthermore, in small airways, asthmatic lungs showed a greater density of CD45-positive cells (p < 0.01) and eosinophils (p < 0.01) in the outer compared with the inner airway wall region. These observations indicate that there are regional variations in inflammatory cell distribution within the airway wall in patients with asthma that are not observed in airways from patients with cystic fibrosis. We speculate that this inflammatory cell density in peripheral airways in severe asthma may relate to the peripheral airway obstruction characteristic of this condition. 相似文献
995.
Classic adamantinoma of the long bones is a rare, low-grade malignant neoplasm arising most often in the tibia and usually in patients during the second to fifth decades. Although adamantinomas have been described in children, the histologic pattern in this age group is different from that seen in adults and resembles osteofibrous dysplasia. The usual pattern of adamantinoma in children has been termed "differentiated adamantinoma" and follows a benign course. We report a case of adamantinoma in the proximal tibia of a 3-year-old patient. The lesion had abundant epithelial component with formation of keratin pearls, a pattern that has been described only in classic adamantinoma occurring in adults. Since differentiated adamantinomas are essentially benign and classic adamantinomas are low-grade malignancies, the finding of a classic variant at this young age raised important therapeutic and prognostic issues. 相似文献
996.
Hemocyanins are giant oxygen transport proteins found in many arthropods and molluscs. Freely dissolved in the hemolymph, they are multisubunit proteins that contain many copies of the active site, a copper atom pair that reversibly binds oxygen. Octopus hemocyanin is composed of ten subunits, each of which contain seven oxygen-binding "functional units". The carboxyl-terminal 47 kDa functional unit, Odg, is a proteolytic isolate that binds oxygen reversibly while exhibiting slight Bohr and magnesium ion effects. In this work we present the X-ray structure determination and analysis of Odg at 2.3 A resolution. Odg has two structural domains: a largely alpha-helical copper binding domain, and a five-stranded anti-parallel beta-sandwich with the jelly roll topology found in many viruses. Six histidine residues ligate the copper atoms, one of which is involved in a thioether bridge. The results show that the hemocyanin from the mollusc and that from the arthropod have distinct tertiary folds in addition to the long recognized differences in their quaternary structures. Nonetheless, a comparison of Octopus and horseshoe crab hemocyanin reveals a similar active site, in a striking example of perhaps both convergent and divergent evolution. 相似文献
997.
OBJECTIVES: Autologous fat has been used as a bulking implant material for stress urinary incontinence. There is considerable controversy as to the ultimate fate of the grafted fat. This study was conducted to determine the fate of autogenous fat implanted into the bladder of rats. METHODS: Two groups of adult female rats were studied. In the test animals (group 1, n = 20), mesenteric adipose tissue (1 mL) was harvested and homogenized with an equal weight of sterile saline. Using a 25-gauge needle, 0.5 g of saline-fat mixture was injected into the dorsal bladder neck submucosa. Control animals (group 2, n = 12) were injected with sterile saline only. A subset of animals from each group were killed after 7, 35, 105, and 1 50 days, and the bladder and urethra were fixed. The fixed tissue was examined microscopically and photographed at each follow-up period. RESULTS: Seven days after injection of fat, there was a pronounced acute inflammatory reaction with numerous polymorphonuclear leukocytes and macrophages at the site of fat injection. There was minimal inflammatory reaction at the site of saline injection. By day 35, most of the fat had been eliminated by these phagocytes because of severe acute and chronic inflammation. By day 105, the submucosa tissue of the experimental rats had returned to normal visually and to a flat surface, lacking the appearance of a sizable "bulge" as shown at days 0 and 7. Histopathologic findings were also similar to the control rats. Inflammatory cells were no longer present by day 105. CONCLUSIONS: The implantation of homogenized, autologous fat in the rat urinary bladder submucosa causes acute and chronic inflammation and fat necrosis. The severe phagocytosis at the implant sites eliminates the vast majority of the devitalized implanted fat during the first month. 相似文献
998.
999.
1000.
ME Solov''eva VS Akatov VV Leshchenko AA Kudriavtsev 《Canadian Metallurgical Quarterly》1998,8(2):194-199
OBJECT: The goal of this study was to investigate the impact of mild or moderate degrees of degenerative or ischemic encephalopathy on predicting clinical outcome following unilateral posteroventral medial pallidotomy for treatment of advanced Parkinson's disease (PD). METHODS: Thirty-five patients with PD were studied prospectively. The presence and degree of cortical atrophy, ventriculomegaly, deep white matter lesions (DWML), periventricular lucencies (PVL), and the presence of lacunes and status cribriformis (multiple and bilateral enlarged Virchow-Robin spaces) were determined by magnetic resonance (MR) imaging before the patients underwent stereotactic pallidotomy performed according to a standard protocol. Clinical outcome was measured using a standard battery of tests including application of the Unified Parkinson's Disease Rating Scale (UPDRS). The preoperative MR imaging features were correlated with UPDRS subscores such as motor "off' score, the activities of daily living (ADL) off score, the off subscore for bradykinesia, the percentage of "on" time dyskinesias, and a global outcome rating. The MR findings were also correlated with the occurrence of side effects. Global outcome was rated as markedly improved in 22 patients (63%) and as moderately improved in 12 patients (34%) 6 months postoperatively. At the 1-year follow-up examination, global outcome in 31 patients was rated as markedly improved in 14 patients (45%), as moderately improved in another 14 (45%), as slightly improved in two (6%), and as worse in one patient (3%). The mean UPDRS motor off score changed from 58.7 preoperatively to 33.2 at 6 months and 33.4 at 1 year (p < 0.0001), the ADL off score from 31.8 to 18.2 at 6 months and 18.6 at 1 year (p < 0.0001), the off score from contralateral bradykinesia from 11.6 to 5.6 at 6 months and 4.1 at 1 year (p < 0.0001), and the percentage of awake time with dyskinesias from 37.4 to 17.4% at 6 months and 21.1% at 1 year (p < 0.0001). The presence of mild or moderate degrees of cortical atrophy, PVL, and DWML had no effect on clinical outcome. Patients with status cribriformis and those with lacunes tended to show comparatively less improvement in the UPDRS ADL off score (p = 0.014 and p = 0.016, respectively) at 6 months. This tendency was also present in patients with status cribriformis 1 year postoperatively (p = 0.046). Patients with both status cribriformis and lacunes had a higher incidence of transient altered mental status immediately postoperatively (p = 0.05). CONCLUSIONS: Mild-to-moderate degrees of cortical atrophy, ventriculomegaly, and ischemic encephalopathy do not predispose patients to less favorable outcomes following unilateral pallidotomy. Patients with both status cribriformis and lacunes have a higher risk of transient side effects; however, with regard to clinical outcome, these patients should not be denied surgical treatment. 相似文献