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21.
AN Reshetilov DA Efremov PV Iliasov AM Boronin NI Kukushskin RV Greene TD Leathers 《Canadian Metallurgical Quarterly》1998,13(7-8):795-799
Amperometric biosensors register oxygen depletion in response to analyte catabolism, and thus are limited by the availability of dissolved oxygen. Microbial sensors containing immobilized cells of Gluconobacter oxydans were hyperoxygenated to 400% of control levels and the effects on sensor responses to glucose were determined. Oxygenated perfluorodecalin (a completely fluorinated organic substance) was as effective in hyperoxygenation as direct sparging with O2, increasing sensor base medium oxygen concentrations from 9.3 to 37 mg/l. Hyperoxygenation enhanced maximal biosensor response amplitudes, particularly at high cell loading densities. Maximal response rates were also improved, although less dramatically. Results suggest that hyperoxygenation may be a new general approach for modulating biosensor responses. 相似文献
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R Roure C Collet C Deschaumes-Molinaro A Dittmar H Rada G Delhomme E Vernet-Maury 《Canadian Metallurgical Quarterly》1998,78(2):99-108
The proliferative rate of a tumor has been considered predictive of its clinical course. We evaluated the expression of the proliferative marker Ki-67 and its relationship to survival, disease-free survival and other clinicopathologic variables in both stage I and stage II non-small cell lung cancer (NSCLC). A total of 260 patients with surgically resected stage I (n = 193), and II (n = 67) NSCLC with at least 5 years follow-up were identified. The median survival for patients with low expression of Ki-67 (< or = 25%) was 54 months, while for those with high expression (> 25%), it was 45 months (P = 0.1). The disease-free survival in patients with low expression of Ki-67 was 59 months while it was only 32 months for patients with high Ki-67 (P = 0.1). Out of 136 patients, 84 (62%) had both increased S-phase (> 8%) and high Ki-67 (P = 0.001). A total of 28 of 30 patients who had loss of antigen A had high expression of Ki-67 (93.3%) (P = 0.03). Ki-67 expression was also higher in squamous cell (54/63, 85.7%) compared to nonsquamous cell cancer (70/108, 64%) (P = 0.03). We also analyzed for the presence of symptoms with survival. The presence of symptoms was not found to be statistically significant, for overall survival (P = 0.33) or disease-free survival (P = 0.72). When individual symptoms were analyzed, the presence of cough was statistically significant for both overall and disease-free survival. The median survival was 39 months for patients with cough, and 57 months for patients without cough (P = 0.04). Multivariate analysis showed higher N and T stages, presence of cough and loss of antigen A, predicted for poorer overall survival. Higher N and T stages, loss of antigen A, presence of mucin and cough and increased expression of Ki-67 predicted decreased disease-free survival. Although we did not find a statistically significant difference between low and high Ki-67, there was a trend for a poorer overall and disease-free survival in patients with high Ki-67 expression. Larger studies may be needed to prove a statistically significant effect of Ki-67 on survival. Future studies should assess the potential prognostic significance of the presence of symptoms (particularly cough) in addition to clinical-pathologic variables (such as T and N stage) and biological markers in patients with early stage NSCLC. 相似文献
24.
IV Bychkovskaia RP Stepanov PV Antonov DN Cherniakova 《Canadian Metallurgical Quarterly》1996,36(6):926-931
Electron microscopic investigation of capillary endothelium cells in myocardium of irradiated rats revealed an unusual effect of persistent increase of probability of cell damage, similar in many relations to that described earlier for various unicellular species. New effect, unlike those traditionally studied, is characterised by non-stochastic nature, large number of the involved cells, reveals itself even after faint influences, and can be induced as well by agents other than radiation. The question is put on the probable commonness between these changes and the pseudomutagenesis which has the similar phenomenology. 相似文献
25.
AV Demin AV Kolesnikov MA Olfer'ev PV Favorov KV Fegeding AG Gabibov NV Gnuchev 《Canadian Metallurgical Quarterly》1998,34(10):1333-1337
A new system for the expression of a catalytic light chain antibody to the vasoactive intestinal peptide is described. The system made possible the isolation the large amounts of a homogeneous protein without any additional peptide domains. The preparation obtained can be used in further experiments on light chain crystallization and in X-ray-structural analysis of its catalytic center. 相似文献
26.
TB Lovelace JT Mellonig RM Meffert AA Jones PV Nummikoski DL Cochran 《Canadian Metallurgical Quarterly》1998,69(9):1027-1035
The purpose of this study was to compare the use of bioactive glass to demineralized freeze-dried bone allograft (DFDBA) in the treatment of human periodontal osseous defects. Fifteen systemically healthy patients (6 males and 9 females, aged 30 to 63) with moderate to advanced adult periodontitis were selected for the study. All patients underwent initial therapy, which included scaling and root planing, oral hygiene instruction, and an occlusal adjustment when indicated, followed by re-evaluation 4 to 6 weeks later. Paired osseous defects in each subject were randomly selected to receive grafts of bioactive glass or DFDBA. Both soft and hard tissue measurements were taken the day of surgery (baseline) and at the 6-month re-entry surgery. The clinical examiner was calibrated and blinded to the surgical procedures, while the surgeon was masked to the clinical measurements. Statistical analysis was performed by using the paired Student's t test. The results indicated that probing depths were reduced by 3.07 +/- 0.80 mm with the bioactive glass and 2.60 +/- 1.40 mm with DFDBA. Sites grafted with bioactive glass resulted in 2.27 +/- 0.88 mm attachment level gain, while sites grafted with DFDBA had a 1.93 +/- 1.33 mm gain in attachment. Bioactive glass sites displayed 0.53 +/- 0.64 mm of crestal resorption and 2.73 mm bone fill. DFDBA-grafted sites experienced 0.80 +/- 0.56 mm of crestal resorption and 2.80 mm defect fill. The use of bioactive glass resulted in 61.8% bone fill and 73.33% defect resolution. DFDBA-grafted defects showed similar results, with 62.5% bone fill and 80.87% defect resolution. Both treatments provided soft and hard tissue improvements when compared to baseline (P < or = 0.0001). No statistical difference was found when comparing bioactive glass to DFDBA; however, studies with larger sample sizes may reveal true differences between the materials. This study suggests that bioactive glass is capable of producing results in the short term (6 months) similar to that of DFDBA when used in moderate to deep intrabony periodontal defects. 相似文献
27.
The catecholamine hypothesis of progressive spinal cord necrosis following mechanical trauma was investigated with the histofluorometric method. Forty-four adult mongrel dog were examined as control, L1 crush-injured, and crush-injured with prior T1 total transection groups. In crush injured dogs, catecholamines were present in a 1 cm length of white matter at the crush site, with the greatest accumulation in the deep lateral and ventral funiculi. Gray matter fluorescence was not enhanced. Prior transection did not abolish the intense accumulation of catecholamines at the site of the cord injury. We propose that the catecholamines accumulating at the cord injured site are not central in origin, but represent an uptake mechanism into white matter as a reflection of cord microperfusion. 相似文献
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Maternal lymphocyte reactivity to human trophoblast antigens was studied in placentas of gestational ages 8 to 14 weeks and 32 to 34 weeks, respectively. Significant trophoblast lysis became apparent after 24 hours' incubation in the latter case compared with a time lag of 72 hours in the terminated gestations. Maternal cellular immunity, therefore, was not detected during the first 3 1/2 months of pregnancy, but was detectable by the time of parturition. The possible significance is discussed with respect to the antigenic stimulus and survival of the fetal allograft. 相似文献