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991.
992.
In an attempt to develop an assay for the susceptibility of plasma lipids to oxidation, we have studied the kinetics of copper-induced oxidation in diluted serum and plasma prepared with different anticoagulants (heparin, citrate and EDTA) by monitoring the absorbance of oxidation-products at several wavelengths. These studies revealed the complex and interrelated effects of the water-soluble antioxidant ascorbic acid, citrate and chloride ions on the kinetics of copper-induced oxidation of plasma lipids. Specifically, the onset of oxidation induced by copper-citrate chelates is only slightly affected by chloride ions and is accelerated upon increasing the copper concentration. By contrast, in the absence of citrate, the lag preceding oxidation in diluted serum or plasma (but not the maximal rate of oxidation) depends markedly on the chloride concentration in the diluting medium. In the absence of Cl-, the lag preceding oxidation is a decreasing saturable function of copper concentration, whereas in a normal phosphate-buffered saline solution (PBS), the lag shows a biphasic dependence on copper concentration such that at copper concentrations above 10-30 microM (depending on the extent of plasma dilution), increasing the concentration of copper results in prolongation of the lag. This dependence of copper-induced oxidation on the concentration of copper is not observed for dialyzed serum unless ascorbic acid is added. Our interpretation of these results is that water-soluble reductants and chloride ions act synergistically to stabilize Cu+, on the expense of Cu2+. Quenching of free radicals by Cu+ may be responsible for the prolongation of the lag at high copper concentrations, with no reduction of the maximal rate of oxidation. In spite of the complex dependencies described above, spectrophotometric monitoring of the kinetics of oxidation of plasma lipids, under 'optimized conditions' (50-fold diluted serum, in PBS containing 720 microM sodium citrate and 100 microM copper), agrees with independent measurements of the consumption of polyunsaturated fatty acids. Hence, the spectroscopic method may become useful for evaluation of the susceptibility of plasma lipids to oxidation. This possibility, however, has yet to be elucidated through investigations of the correlation between the susceptibility of serum lipids to copper-induced oxidation in vitro and clinical factors of significance.  相似文献   
993.
We examined the pattern of FtsZ localization in a Bacillus subtilis minCD mutant. When grown in minimal medium, the majority (approximately 89%) of the minCD mutant cells with an FtsZ ring had a single, medially positioned FtsZ ring. These results indicate that genes in addition to minCD function to restrict the number and position of FtsZ rings. When grown in rich medium, greater than 50% of the minCD mutant cells had multiple FtsZ rings, indicating significant differences in regulation of FtsZ ring formation based on growth medium.  相似文献   
994.
995.
Cytokines play an essential role in the regulation of lymphocyte survival and growth. We have analyzed the pathways activated by IE-2 that lead to protection from apoptosis and cell proliferation. IL-2 can act as a long-term growth factor in 32D cells expressing the wild-type human (hu)IL-2R beta. By contrast, cells expressing a truncated form of the huIL-2R beta, which is able to induce Bcl-2 and c-myc expression but not STAT5 activation, were not protected from apoptosis by IL-2; consequently, they could not be grown long term in the presence of IL-2. However, IL-2 promoted cell cycle progression in cells bearing the truncated huIL-2R beta with percentages of viable cells in the G0/G1, S, and G2/M phases similar to cells expressing the wild-type huIL-2R beta. Transplantation of a region from the erythropoietin receptor, which contains a docking site for STAT5 (Y343) to the truncated huIL-2R beta, restored the ability of IL-2 to signal both activation of STAT5 and protection from apoptosis. By contrast, transplantation of a region from the huIL-4R alpha containing STAT6 docking sites did not confer protection from apoptosis. These results indicate that the IL-2-induced cell cycle progression can be clearly distinguished from protection from apoptosis and that STAT5 participates in the regulation of apoptosis.  相似文献   
996.
This clinical case report demonstrates the clinical effectiveness of a new form of soft tissue mobilization in the treatment of excessive connective tissue fibrosis (scar tissue) around an athlete's injured ankle. The scar tissue was causing the athlete to have pain with activity, pain on palpation of the ankle, decreased range of motion, and loss of function. Surgery and several months of conventional physical therapy failed to alleviate the athlete's symptoms. As a final resort, augmented soft tissue mobilization (ASTM) was administered. ASTM is an alternative nonsurgical treatment modality that is being researched at Performance Dynamics (Muncip, IN). ASTM is a process that uses ergonomically designed instruments that assist therapists in the rapid localization and effective treatment of areas exhibiting excessive soft tissue fibrosis. This is followed by a stretching and strengthening program. Upon the completion of 6 wk of ASTM therapy, the athlete had no pain and had regained full range of motion and function. This case report is an example of how a noninvasive augmented form of soft tissue mobilization (ASTM) demonstrated impressive clinical results in treating a condition caused by connective tissue fibrosis.  相似文献   
997.
This paper describes a measure of explained variation (MEV) of survival times for a given regression model used in survival analysis. It quantifies the predictive power of a set of prognostic factors in the model, and therefore provides useful information for more precise prediction of patient prognosis, and for designing randomized clinical trials with the capability of determining treatment effects. The MEV defined in this article is asymptotically derived from the squared product-moment correlation; it can be interpreted as an adaptation of the multiple correlation coefficient for the normal linear model to the survival time regression model. Monte-Carlo simulations are performed to investigate the statistical behavior of the proposed MEV. The MEV is applied to estimate the predictive power of several sets of prognostic factors for gastric cancer in Japan using data from a large clinical trial.  相似文献   
998.
Forty cadaveric flexor digitorum profundus tendons were repaired using the Tajima, Halsted, Silfverskiold, or Savage techniques. The tendons were cyclically loaded in sets of 4,000 cycles beginning at 25 N and increasing by 10-N increments until failure occurred. Gap formation was continuously monitored with an extensiometer. Only the Savage repair group consistently withstood 4,000 cycles of 25-N loading, with respect to 2-mm gap formation and repair rupture. Tendon repairs subjected to cyclic loading demonstrated gap formation and repair rupture at lower loads than with static testing. Of the methods of flexor tendon repair tested, only the Savage technique could withstand simulated early active motion.  相似文献   
999.
1000.
BACKGROUND: The eosinophil granulocyte is an inflammatory cell that plays an active part in diseases such as asthma and rhinitis. This study aimed to investigate oxidative metabolism by blood eosinophils taken from allergic rhinitis patients, asthmatics, and nonallergic controls before and during the birch-pollen season. METHODS: Twenty patients with allergy to birch pollen and seasonal symptoms of rhinitis, some of whom were also asthmatic, were followed before and during the birch-pollen season in Sweden. The cells were purified using a Percoll gradient and the MACS system. Eosinophil purity in all samples was > 95%. Oxidative metabolism was measured by a chemiluminescence (CL) assay, with luminol and lucigenin acting as enhancers, and PMA, serum-treated zymosan (STZ), interleukin (IL)-5, or RANTES as stimuli. RESULTS: The allergic subjects showed reduced luminol CL when activated before the season with PMA (P = 0.040) or STZ (P = 0.0055). This was not seen during pollen exposure. STZ-activated lucigenin CL was also reduced before the season (P = 0.0027). The reduction was most evident in the group with asymptomatic rhinitis. In terms of eosinophil stimulation, IL-5 and RANTES were equally effective in allergic and nonallergic subjects, both before and during the pollen season. CONCLUSIONS: Blood eosinophils from asymptomatic allergics may have a lower capacity to produce oxygen-free radicals than eosinophils from nonallergics.  相似文献   
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