Disparity of serum transferrin receptor measurements among different assay methods

OBJECTIVE: To highlight differences in the quantification of transferrin receptor (TfR) concentration (a reliable index of iron deficiency) between three different assay methods. DESIGN: Methods comparison of TfR measurements in 'elevated' and 'normal' human sera using the Ramco, Quantikine and 'Lab' assays. SETTING: The Hospital for Sick Children, Toronto, Ontario, Canada. SUBJECTS: Pooled TfR for elevated and normal human sera obtained from the Ramco TfR assay kit. MAIN OUTCOME MEASURES: Differences between TfR concentrations in normal and elevated samples and repeatability for each assay method and limits of agreement in TfR quantification between assay methods. RESULTS: The mean TfR concentrations for the elevated reference serum samples was higher than the normal reference samples within each individual assay (P < 0.001); however, measurement agreement between methods was poor. CONCLUSIONS: Recognition of the relative differences in the values obtained from each of the assays should affect the interpretation of TfR concentration as an index of iron deficiency.     

Effect of feeding methods in infants on serum lipid profile

Mothers very often do not start to breast feed their children, or stop very quickly and introduce various formulas based either on modified or unmodified cow's milk. These infant formulas differ from human milk in their chemical composition. Breast milk is the most suitable source of all nutrients required for the development of a newborn or infant. The serum levels of total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides and phospholipids were determined. The influence of the type of feeding on the levels of the above-mentioned lipids was analyzed. Higher serum levels of triglycerides in babies fed formulas based on modified cow's milk than in those fed formulas based on unmodified milk were found. Higher serum levels of phospholipids were found in breast-fed babies than in those fed formulas based on unmodified cow's milk.     

Unfolding of acrylodan-labeled human serum albumin probed by steady-state and time-resolved fluorescence methods

Steady-state and time-resolved fluorescence spectroscopy was used to follow the local and global changes in structure and dynamics during chemical and thermal denaturation of unlabeled human serum albumin (HSA) and HSA with an acrylodan moiety bound to Cys34. Acrylodan fluorescence was monitored to obtain information about unfolding processes in domain I, and the emission of the Trp residue at position 214 was used to examine domain II. In addition, Trp-to-acrylodan resonance energy transfer was examined to probe interdomain spatial relationships during unfolding. Increasing the temperature to less than 50 degrees C or adding less than 1.0 M GdHCl resulted in an initial, reversible separation of domains I and II. Denaturation by heating to 70 degrees C or by adding 2.0 M GdHCl resulted in irreversible unfolding of domain II. Further denaturation of HSA by either method resulted in irreversible unfolding of domain I. These results clearly demonstrate that HSA unfolds by a pathway involving at least three distinct steps. The low detection limits and high information content of dual probe fluorescence should allow this technique to be used to study the unfolding behavior of entrapped or immobilized HSA.     

Interaction of benzothiadiazides with human serum albumin studied by dialysis and spectroscopic methods

The interaction of a series of benzothiadiazides with human serum albumin (HSA) was investigated by equilibrium dialysis (ED) and spectroscopic methods including circular dichroism (CD). The primary binding site of benzothiadiazides was designated site II, the diazepam site on the HSA molecule, as indicated by displacement experiments using different site-selective probes. Tyrosine and lysine amino acid residues were probably involved in the binding site of these compounds to HSA. Both electrostatic and hydrophobic interactions were found to play a role in the binding of these compounds to HSA. Among the compounds tested, chlorothiazide had the highest affinity (K1 = 5.5 x 10(4) M-1, K2 = 5.8 x 10(3) M-1). The primary binding affinity of the compounds for HSA was of the order: chlorothiazide > cyclopenthiazide > polythiazide > ethiazide > trichlormethiazide = methyclothiazde > hydrochlorothiazide. Binding was insensitive to the N-B transition of HSA. The binding site is proposed to consist of a cationic site on the surface of the HSA molecular with a hydrophobic crevice to accommodate the aromatic ring of the compounds. Positions 3 and 7 of the benzothiadiazide molecule is thought to affect the binding affinity to HSA.     

Evaluation of three commercially available menual "kit" methods for triglycerides in serum

We compared three commercially available kits for use in determining triglycerides (triacylglycerols) in serum, by different methods, for accuracy and precision, with use of pooled sera of low, normal, and high triglyceride concentrations. Accuracy varied from -17% to +16% of the independently determined value, depending on the method and triglyceride concentration. In general, the Calbiochem method was the most nearly accurate, and only it met Center for Disease Control criteria for precision at all three triglyceride concentrations. The relationships of mean values to the suggested normal range for each method varied, some significant differences being found. Our data demonstrate the importance of a correlation between the independently determined value and the normal range for the method used and stresses the need for normal-range values to accompany all patients' reports.     

三鑫金铜矿临时保安矿柱回采方法选择与应用

为高效回采三鑫金铜矿重新圈定临时保安矿柱释放的矿体,在充分考虑采场参数、回采顺序及安全稳定的情况下,初步选择了盘区分段回采阶段充填采矿法、盘区分段回采分段充填采矿法和盘区机械化上向分层充填采矿法3种采矿方法.在综合比较3种采矿方法的生产能力、安全性和经济等因素后,确定盘区分段回采阶段充填采矿法为最优方案.该方案具有工艺...     

低品位急倾斜中厚以下矿体采矿方法优选

获各琦铜矿5勘探线以西铅锌矿体位于铜矿体下盘,受上盘铜矿体回采及充填水的影响,矿体完整性受到严重破坏,矿岩稳固性大大降低,同时矿石品位较低,回采难度大。经技术经济对比分析,推荐采用点柱式上向水平分层充填采矿法回采该范围内中厚以下矿体,采场生产能力250 t/d,采矿损失率16%,矿石贫化率8%~10%,采矿成本84.43元/t。以该矿1630中段为例,采用点柱式上向水平分层充填采矿法能创造利润总额2 709.45万元。     

用KD—KS方法设计圆管拉拔配模时△D和△S值的选取

用KD－KS方法设计圆管拉拔配模时经验参数△D和△S的值,已能将经验和理论结合起来进行选取;并对计算结果“不到位”,提出了4种修正方法。△D对△D.max和△S对△S.max的比值是△D和△S取值是否合理的判据。△D值和△S值的选取,除了要使计算结果“到位”,还应该考虑圆管的材质和工艺条件及其要求。     

Determination of inorganic phosphorus on the (Cobas) Bio (direct method without deproteinization) (author's transl)

The direct molybdate method for the determination of inorganic phosphorus was adapted to the (Cobas) Bio centrifugal analyzer. We evaluated test characteristics such as reaction time, linearity range, accuracy and precision within series and from day to day. Accuracy was checked using control sera, three different types of recovery experiments, and by experiments running in parallel. Because the results of the determination of inorganic phosphorus depend greatly on the method and the procedure used (with/without deproteinization), we checked the accuracy not only by experiments running in parallel, but by comparison with the following methods: the malachite green method without and with two different techniques for deproteinization, the molybdate/p-methylaminophenol sulfate method with and without deproteinization, and the molybdate/vanadate method with deproteinization. Using patients' sera as well as control sera, it was shown that the preferred molybdate method gave, within the normal range of errors, the same results as the malachite green method without deproteinization.     

High prevalence and usual persistence of serum monoclonal immunoglobulins evidenced by sensitive methods in renal transplant recipients

BACKGROUND: The occurrence of serum monoclonal immunoglobulins in kidney transplant recipients is well known but their significance and predictive value for the occurrence of lymphoma are a matter of debate. We therefore conducted a study of monoclonal immunoglobulins by a sensitive method during the long-term follow up of grafted patients. METHODS: Monoclonal immunoglobulins were characterized by high-resolution electrophoresis, conventional immunoelectrophoretic analysis, and a sensitive Western blotting procedure in the serum from 84 renal transplant recipients prior to grafting and subsequently, with a 1-8-year follow-up and excluding the patients who developed posttransplant lymphoma. RESULTS: Low abundance monoclonal immunoglobulins were detectable prior to transplantation in 56 cases (66.6%) and after graft in 72 cases (85.5%) (and in 1 case (1.2%) and 18 cases (21.4%) of cases respectively, by immunoelectrophoresis). These abnormalities were often multiple in individual sera. Monoclonal components detected by immunoblotting were transient in 23.8% of patients only (whereas those evidenced by immunoelectrophoresis usually became undetectable by this method) and their pattern was remarkably stable in the majority of cases. The frequency of post-transplant monoclonal immunoglobulins was higher in patients of more than 50 years of age than in younger patients. The appearance of monoclonal components after grafting and their transient character correlated with CMV infections. No correlation was found with various other parameters. The isotypic distribution of monoclonal immunoglobulins with an IgM, IgG3, and IgG1 predominance and an abnormally low kappa/lambda ratio was the same as that observed in various immunodeficiency states. The monoclonal immunoglobulin pattern in three further patients who developed post-transplant lymphoma was unremarkable. CONCLUSION: Monoclonal immunoglobulins hence are not discriminant for lymphoma and their characterization does not appear to be necessary in the evaluation of followed up grafted patients, at least for a prediction of post-transplant lymphoma.     

Study of serum antibodies of different classes as a methods of defining the genesis of transitory salmonella carrier state]

An 18 month Thoroughbred gelding was diagnosed on cardiac catheterization as having an interventricular septal defect. Right side cardiac blood pressures were within the normal range and confirmation of the diagnosis came from changes in the blood pO2 and pCO2 between the right atrium and right ventricle. The significance of these values is discussed.     

接口继电器的选择

详细介绍了选择接口继电器的注意事项,并从性价比上突出菲尼克斯端子继电器的优点。     

关于方案比选中经济评价指标选取的探讨

独立方案选用财务内部收益率进行比选;计算期相同的互斥方案可选用差额投资财务内部收益率、净现值和净年值进行比选,计算期不同的互斥方案需进行处理,使其满足时间可比条件,选用净年值进行比选。