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2.
W J Allard C D Cheli D L Morris J Goldblatt Y Pierre L Kish Y Chen J Dai R L Vessella D W Chan M K Schwartz Z Zhou K K Yeung 《The International journal of biological markers》1999,14(2):73-83
We conducted a multicenter evaluation of the analytical and clinical performance of the automated Bayer Immuno 1 complexed PSA (cPSA) assay, and compared assay performance to the Bayer Immuno 1 PSA assay. We sought to determine whether measurements of cPSA could be of clinical utility in the management of patients with prostate cancer. Results of the 10-day imprecision across three evaluation sites produced total CV < 2.50% and an analytical sensitivity of 0.02 microgram/L. There was an increased trend in clinical sensitivity for prostate cancer with increasing stage of disease (71-86%). Clinical specificity for patients with benign urogenital disease was 74.8%, and for other nonprostate diseases ranged from 91.1-100%. Retrospective serial monitoring of 155 patients with prostate cancer demonstrated concordance of cPSA measurements to clinical status for 97% of the patients analyzed. Results from the clinical studies using the Bayer Immuno 1 cPSA assay were comparable to results obtained with the Bayer Immuno 1 PSA assay. The Bayer Immuno 1 cPSA assay demonstrates analytical performance and clinical effectiveness in the management of prostate cancer patients during the course of disease and therapy. 相似文献
3.
K S Yeung M Hoare N F Thornhill T Williams J D Vaghjiani 《Biotechnology and bioengineering》1999,63(6):684-693
This article describes the calibration of a spectroscopic scanning instrument for the measurement of selected contaminants in a complex biological process stream. Its use is for the monitoring of a process in which contaminants are to be removed selectively by flocculation from yeast cell homogenate. The main contaminants are cell debris, protein, and RNA. A low-cost instrument has been developed for sensitivity in the region of the NIR spectrum (from 1900 to 2500 nm) where preliminary work found NIR signatures from cell debris, protein, and RNA. Calibration models have been derived using a multivariate method for concentrations of these contaminants, such as would be found after the flocculation process. Two strategies were compared for calibrating the NIR instrument. In one case, samples were prepared by adding materials representative of the contaminants to clarified yeast homogenate so the contaminant levels were well known but outside the range of interest. In the other case, where samples were like those from the process stream after flocculation and floc removal, there was uncertainty of analysis of contaminant level, but the calibration was in the range of interest. Calibration using process stream samples gave results close to those derived from traditional assays. When the calibration models were used to predict the contaminant concentrations in previously unseen samples, the correlation coefficients between measurements and predictions were above 90% in all cases but one. The prediction errors were similar to the errors in the traditional assays. 相似文献
4.
J.C. Kuo Edward S. Yeung 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1982,229(2)
A separation and detection scheme is presented for the determination of free, esterified and total cholesterol in human serum. Separation is accomplished by reversed-phase high-performance liquid chromatography and the eluate is monitored by the laser-based optical activity detector. The method is simple, accurate and has the advantage of specificity and selectivity when compared with the many methods commonly used. 相似文献
5.
The postnatal induction of serine dehydratase in rat liver 总被引:4,自引:0,他引:4
6.
The mitochondrial outer membrane channel, VDAC, is regulated by a synthetic polyanion 总被引:9,自引:0,他引:9
A synthetic polyanion has been found to modulate the properties of the mitochondrial outer membrane channel, VDAC. This 10 kDa polyanion, first synthesized and described by Konig and co-workers, is a 1:2:3 copolymer of methacrylate, maleate, and styrene. It had been shown to interfere with the access of metabolites to the mitochondrial inner spaces. Here we show that, at nanomolar levels, the polyanion increases the voltage dependence of VDAC channels over 5-fold. Some channels seem to be totally blocked while others display the higher voltage dependence and are able to close at very low membrane potentials (5 mV). At 27 micrograms/ml polyanion, VDAC channels are closed while inserted into liposomes in the absence of any applied potential. The closed state of VDAC induced by the polyanion has similar properties to the closed state induced by elevated membrane potentials. The physical size of the polyanion-induced closed state (in VDAC-containing liposomes) is about 0.9 nm in radius. How this estimate fits with estimates of the channel's open state and estimated volume changes between the open and closed states, is discussed. 相似文献
7.
In 1979 and 1980 the Canadian Paediatric Society''s Nutrition Committee published guidelines for professionals counselling mothers of infants on feeding practices. The practices in 1984-85 of mothers in Toronto were determined for comparison with the practices identified in a similar study conducted in Toronto and Montreal in 1977-78 to ascertain if practices had changed in favour of the recommendations. Between July 1984 and February 1985, 404 metropolitan Toronto mothers of infants were interviewed. Compared with the 1977-78 group of mothers, more of the 1984-85 mothers had chosen to breast-feed and fewer had stopped breast-feeding in the first month. As well, fewer of the 1984-85 infants had been fed unmodified cow''s milk in the first 6 months of life and introduced to solid foods before 4 months of age. We conclude that major changes in infant feeding practices had occurred since 1977-78 and that the 1984-85 practices corresponded closely to the infant feeding guidelines. 相似文献
8.
Summary N-acetylglucosaminidase (NAG), acid phosphatase (ACP) and alkaline phosphatase (AKP) were localised histochemically in fixed cells from the 37-day-old rat epididymis grown in static monolayer culture for 2–8 days. ACP and NAG were cytosolic enzymes found in perinuclear positions, whereas staining of AKP was consistent with a membranous position. These enzymes were also examined in frozen tissue sections of the epididymis, from rats of the equivalent age, where NAG had intense activity in both supra- and infra-nuclear cytoplasm and ACP was more active apically. For the first time AKP was localised along basolateral membranes of the epithelium and in the lumen of the mid-caput region. The monolayer in culture was of principal cells only and they maintained their polarity and ultrastructural characteristics, but the height of the cells was reduced compared to that obtained in situ. 相似文献
9.
Magnesium ion exerts a central role in the regulation of inhibitory adenosine receptors. 总被引:4,自引:2,他引:2 下载免费PDF全文
Guanine nucleotides and Mg2+ differentially regulate agonist binding to adenosine (Ri) receptors in fat-cell plasma membranes. GTP alone decreases binding of the agonist ligand [3H]N6-cyclohexyladenosine (CHA) by increasing the dissociation constant (Kd). Mg2+ alone also decreases [3H]CHA binding, which is associated with a decrease in the number of receptors and in the dissociation constant. In the presence of Mg2+, the effect of GTP is to increase [3H]CHA binding by increasing the total number of receptors. It thus appears that Mg2+ acts specifically at a bivalent-cation site which, with GTP, regulates agonist binding. This putative Mg site is highly sensitive to alkylating agents. Mild treatment with N-ethylmaleimide (NEM) abolishes the characteristic GTP effect on agonist binding in the presence of Mg2+. In addition, the effect of Mg2+ alone is also eliminated. The effect of GTP alone is largely unaltered. Studies of the adenylate cyclase activity indicate that this NEM treatment also abolishes the inhibition of basal activity by adenosine analogues, whereas guanylyl imidodiphosphate inhibition of forskolin-stimulated activity is only slightly impaired at this NEM concentration. These observations indicate that a Mg2+ 'site' or 'component' is required for the integration of receptor (Ri) occupancy with regulation of catalytic activity (C). The regulatory role of Mg2+ is more demonstrable in receptor-GTP-regulatory-protein (Ri-Ni) interactions than in GTP-regulatory-protein-catalytic-unit (Ni-C) interactions. 相似文献
10.
Cytokinin-induced switch in development in excised cotyledons of radiata pine cultured in vitro 总被引:2,自引:0,他引:2
Victor M. Villalobos Melvin J. Oliver Edward C. Yeung Trevor A. Thorpe 《Physiologia plantarum》1984,61(3):483-489
Cotyledons of Pinus radiata D. Don were cultured under shoot-forming (plus cytokinin) and elongating (minus cytokinin) conditions. Using. autoradiographic and precursor incorporation techniques, the sites and rate of macromolecular synthesis were examined during the first five days in culture. Active incorporation of 3 H-thymidine, 3 H-uridine and 3 H-leucine occurred. In shoot-forming cotyledons the incorporation became preferentially located in the epidermal and sub-epidermal cell layers in contact with the medium. In elongating cotyledons, in contrast, incorporation was randomly distributed, and the amount of incorporation declined with time. Biochemically, differences in DNA, RNA and total protein synthetic patterns were observed. In elongating cotyledons the rates of RNA and protein synthesis were higher during the first 48 h than in shoot-forming tissues, after which the synthetic rates were similar. Two peaks of newly formed DNA were observed in both tissues. These findings indicate that the cytokinin-induced changes in developmental pathways began within 24 h in culture. 相似文献