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171.
N Koffi E Aka-Danguy A Ngom B Kouassi BA Yaya M Dosso 《Canadian Metallurgical Quarterly》1998,15(5):643-647
OBJECTIVE: To assess the quantity and nature of the proteins that adsorb to hydrocephalus shunt catheters after implantation, and to determine whether sufficient could accumulate to obstruct the catheter. DESIGN: Elution of proteins from 102 explanted shunt catheters, with protein assay and electrophoresis of the eluate, and scanning electron microscopy (SEM) of the catheters. RESULTS: The amount of protein elutable was extremely low, and significant protein, apart from a thin film, was not found on SEM. Qualitative analysis disclosed that most of the adsorbed protein was albumin. CONCLUSIONS: Protein deposition on hydrocephalus catheters does not occur in sufficient quantities to cause catheter obstruction. 相似文献
172.
173.
Fermentation of xylooligosaccharides by 11 strains of Selenomonas ruminantium was examined. Xylooligosaccharides were prepared by the partial hydrolysis of oat spelt xylan in dilute phosphoric acid (50 mM, 121 degrees C, 15 min) and were added to a complex, yeast extract-Trypticase-containing medium. Strains of S. ruminantium varied considerably in their capacity to ferment xylooligosaccharides. Strains GA192, GA31, H18, and D used arabinose, xylose, and the oligosaccharides xylobiose through xylopentaose, as well as considerable quantities of larger, unidentified oligosaccharides. Other strains of S. ruminantium (HD4, HD1, 20-21a, H6a, W-21, S23, 5-1) were able to use only the simple sugars present in the substrate mixture. The ability of S. ruminantium strains to utilize xylooligosaccharides was correlated with the presence of xylosidase and arabinosidase activities. Both enzyme activities were induced by growth on xylooligosaccharides, but no activity was detected in glucose- or arabinose-grown cultures. Xylooligosaccharide-fermenting strains of S. ruminantium exhibited considerable variation in substrate utilization patterns, and the assimilation of individual carbohydrate species also appeared to be regulated. Lactic, acetic, and propionic acids were the major fermentation end products detected. 相似文献
174.
Adhesion of cells to biomaterial surfaces is one of the major factors which mediates their biocompatibility. Quantitative or qualitative cell adhesion measurements would be useful for screening new implant materials. Microjet impingement has been evaluated by scanning electron microscopy, to determine to what extent it measures cell adhesion. The shear forces of the impingement, on the materials tested here, are seen to be greater than the cohesive strength of the cells in the impinged area, causing their rupture. The cell bodies are removed during impingement, leaving the sites of adhesion and other cellular material behind. Thus the method is shown not to provide quantification of cell adhesion forces for the metals and culture plastic tested. It is suggested that with highly adherent biomaterials, the distribution and patterns of these adhesion sites could be used for qualitative comparisons for screening of implant surfaces. 相似文献
175.
A method of stratifying the data according to the patterns of missing observations, summarizing each subject's repeated measurements by a summary measure and then comparing the treatment groups with the help of a distribution-free test based on the summary measure, is used here to compare the efficacy of tacrine dose regimens with that of placebo in a recent trial in Alzheimer's disease patients. The usefulness of the method of meta-analysis for comparing the treatment groups, in the presence of missing data, is also investigated. 相似文献
176.
Teaching portfolios are stimulating much discussion as more comprehensive approaches to evaluating teaching are sought. Portfolios can be used effectively for both formative and summative evaluative purposes. The content of a portfolio may vary greatly, but commonly includes material that reflects student learning, evaluative materials, and a personal statement on the faculty's philosophy of education. Professional growth often accompanies developing a personal teaching portfolio. 相似文献
177.
As many as 230 patients with disseminated sclerosis were examined in the Transcarpathian region. Sick male- and female populations were found out to be almost similar. There were more sick persons in the medium-range areas of the Carpathian Mountains, with a mean age being 35 +/- 5 years. It has been established that intake of spirulina makes for lengthening of remission in those patients with disseminated sclerosis. 相似文献
178.
179.
JE Mortimer F Dehdashti BA Siegel JA Katzenellenbogen P Fracasso MJ Welch 《Canadian Metallurgical Quarterly》1996,2(6):933-939
We assessed the value of positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) and 16alpha-[18F]fluoro-17beta-estradiol (FES) in women with breast cancer for predicting response to systemic therapy. Results of FES-PET were correlated with estrogen receptor (ER) status. Forty-three women with locally advanced or metastatic breast cancer underwent FDG-PET and FES-PET prior to institution of systemic therapy. All patients had measurable disease and had tumors submitted for ER determination. Cancers were considered functionally hormone sensitive if the standardized uptake value of the lesion on FES-PET was >/=1.0 (FES+) and hormone resistant if the standardized uptake value was <1.0 (FES-). Information obtained by FES-PET was compared with the results of ER assays. The tumor response to chemotherapy and hormonal therapy was correlated with intensity of uptake by both FDG-PET and FES-PET. The ER status of the breast cancers was negative (ER-) in 20 patients, positive (ER+) in 21 patients, and unknown in 2 patients. All 20 of the ER- tumors were also FES-. However, of the 21 ER+ tumors, 16 were FES+ and 5 were FES-. Thirty patients were treated initially with chemotherapy, and 21 (70%) demonstrated objective responses. We were unable to correlate the response to chemotherapy with information obtained by FDG-PET or FES-PET. Thirteen patients were treated with hormone therapy, and 8 (61%) responded to that therapy. Only 1 of the 5 patients whose tumors were ER+ but FES- received hormone therapy, and this treatment resulted in disease stabilization only. Multiple sites of disease were assessed by FES-PET in 17 patients with metastatic breast cancer. Functional hormone sensitivity, defined by FES-PET, was concordant with multiple lesions in 13 (76%). Ten patients with locally advanced breast cancer developed recurrent disease. The initial site of recurrence was the breast in 5 patients. Of the 5 patients with systemic recurrence, 4 had disease detected at the site of recurrence on the pretreatment FDG-PET study but not detected on pretreatment computed tomography. In our experience, FDG-PET imaging is more sensitive than conventional imaging methods, including computed tomography, in staging women with breast cancer. When compared with the in vitro assay of ER status, FES-PET has an apparent sensitivity of 76% and specificity of 100%. Our finding of a subset of patients who have tumors that are ER+ and FES- suggests that the functional assessment of hormone sensitivity by PET imaging can identify patients with ER+ disease whose tumors are likely to be hormone refractory. 相似文献
180.
TA Millward CW Heizmann BW Sch?fer BA Hemmings 《Canadian Metallurgical Quarterly》1998,17(20):5913-5922
Ndr is a nuclear serine/threonine protein kinase that belongs to a subfamily of kinases identified as being critical for the regulation of cell division and cell morphology. The regulatory mechanisms that control Ndr activity have not been characterized previously. In this paper, we present evidence that Ndr is regulated by EF-hand calcium-binding proteins of the S100 family, in response to changes in the intracellular calcium concentration. In vitro, S100B binds directly to and activates Ndr in a Ca2+-dependent manner. Moreover, Ndr is recovered from cell lysates in anti-S100B immunoprecipitates. The region of Ndr responsible for interaction with Ca2+/S100B is a basic/hydrophobic motif within the N-terminal regulatory domain of Ndr, and activation of Ndr by Ca2+/S100B is inhibited by a synthetic peptide derived from this region. In cultured cells, Ndr is rapidly activated following treatment with Ca2+ ionophore, and this activation is dependent upon the identified Ca2+/S100B-binding domain. Finally, Ndr activity is inhibited by W-7 in melanoma cells overexpressing S100B, but is unaffected by W-7 in melanoma cells that lack S100B. These results suggest that Ndr is regulated at least in part by changes in the intracellular calcium concentration, through binding of S100 proteins to its N-terminal regulatory domain. 相似文献