High-performance liquid chromatographic determination of plasma histamine after pre-column derivatisation with o-phthaldialdehyde

Summary A reversed-phase high-performance liquid chromatographic (HPLC) method has been developed for the sensitive and highly selective determination of histamine in plasma. This method includes selective extraction of histamine from plasma, pre-column derivatisation in aqueous phase with o-phthaldialdehyde (OPA) and HPLC analysis. The fluorescence of the histamine-OPA-complex was monitored at wavelengths of 350nm excitation and 450nm emission, after isocratic eluation with a mixture of 0.2 M NaCl and methanol. The reproducibility of this method including extraction, derivatisation and detection of histamine was >95% in a range of 0.35–17.6 pmol. The HPLC precision was 99±1% at 4 pmol of histamine. The lower limit of detection was 88fmol. A significantly increased concentration of plasma histamine was detected in patients (n=46) with various liver diseases (0.3–5.2 ng/ml). In comparison the plasma histamine levels of healthy blood donors were in the range of 0.0–0.4 ng/ml (p<0.01).     

Enhanced ionization and population inversion with double-pulse laser heating

A new configuration of double-pulse laser heating is proposed for x-ray laser research. The double-pulse consisting of a main pulse (first) and a "tailed" pulse (second) with less energy can increase the fraction of highly ionized states efficiently. Population inversion in He-like Al ions between the n=3 and 2 levels has been found with such a novel laser heating configuration. The possible physical mechanisms are discussed.     

200Mw发电机组的动态特性分析

应用模态分析技术研究２００Ｍｗ汽轮发电机组转子的动态特性；论述机组起动，运行的安全性和可靠性；探讨事故发生的机制，为机组的状态监测，故障诊断和结构优化提供可靠的依据。     

On sampling by index cases

Using results of Klonecki, optimal C_α-tests of homogeneity for random binomial parameters are obtained from samples collected by the index case method, providing an asymptotically efficient way of judging whether a disease is familial. The efficiency of a traditional test is shown to approach that of the new test as the incidence rate of the disease declines.     

Generation of impulsive pressure wave by spark discharge in water and its propagation

An experimental investigation was performed to find a new method for diagnosing three-dimensional flows in which obstacle bodies or cavities are included by means of a pressure wave. In rectangular closed tanks 200 × 337 × 250 mm (acrylic resin) and 300 × 450 × 400 mm (brass) filled with water, an impulsive pressure wave was generated by an instantaneous small spark discharge. The pressure waveforms were measured at a point on the wall with a high-frequency pressure transducer, and the data were recorded with an A/D converter. The measured wave fluctuations differed depending on wall conditions of the tank and on whether there was a submerged body in the water. The size of the submerged body also affected the pressure fluctuation. When acrylic resin and brass were used as wall materials, both the phase and amplitude of the reflecting wave differed. When a stainless steel sphere of diameters of 50.8, 30.2, or 19.1 mm was submerged in the tank, two kinds of pressure waves were observed, one passing through the sphere and the other diffracted around it. These results suggest the possibility of identifying bodies of simple shape by interpreting the precisely measured output pressure wave signals.     

婴儿低镁血症32例分析

镁是人体内重要的阳离子。报道了南京市第三医院近两年来对３２例婴儿低镁血症的诊断和治疗，并讨论了该症的病因和治疗方法。     

Autoantibodies to thyroglobulin in health and disease

Thyroglobulin (Tg)—a heavily glycosylated, iodinated protein—isa major autoantigen in autoimmune thyroiditis. Tg also induces thyroiditis by immunization of experimental animals. Humans with chronic lymphocytic thyroiditis characteristically produce autoantibodies to thyroglobu lin, but similar autoantibodies are also found in some clinically normal, euthyroid individuals. A comparison of the fine specificity of autoantibodies in humans and in experimentally immunized mice was carried out, based on their ability to inhibit a panel of monoclonal antibodies (MAbs). Patients with autoimmune thyroid disease, as well as normal individuals, produced autoantibodies mainly to the conserved, cross-reactive determinants of thyroglobulin. Patients developed additional autoantibodies to species-restricted epitopes. The determinants recognized by patients with Graves' disease differed in some respects from epitopes recognized by thyroiditis patients or patients with differentiated thyroid carcinoma. Similarly, mice that are genetically susceptible to thyroiditis produced autoantibodies that reacted with the mouse-specific antigenic determinants. Using an autoantibody that reacts with one of the epitopes associated with thyroiditis, a reactive 15-k Da fragment of human Tg—localized at the carboxy end of the molecule—was isolated and sequenced. Iodine plays an important role in the precise specificity of the disease-associated epitope, since T cells from patients with thyroiditis react with iodinated but not noniodinated human thyroglobulin. Addition of iodine to Tg generates new or cryptic epitopes. Use of a selected MAb as a surrogate for the T-cell receptor suggests that a specific iodine-containing epitope is sometimes involved in recognition. Finally, thyroglobulin-reactive autoantibodies exhibit proteolytic activity on thyroglobulin.     

Amyloid beta peptides electrochemistry: A review

Alzheimer disease is a progressive age-related neurodegenerative disorder estimated to affect up to 107 million people by 2050, its pathology is associated with the dysfunction of the amyloid beta (Aβ) peptide mechanism, among others. Electrochemical methods were successfully applied for Aβ electrochemical characterisation and have received increased attention in Aβ research. This review discusses the recent advances on the direct electrochemical detection of Aβ redox mechanisms, fibrilization and interaction with metal ions based on the electrochemical detection of the Aβ′s

,

and

amino acid residues oxidation peaks.     

Electrophoretic separation of amyloid beta peptides in plasma

In this prospective study, for the first time we have separated and quantified amyloid beta (Abeta) peptides in the plasma of patients with Alzheimer's disease (AD, n = 8) and age- and environment-matched healthy controls (n = 9) with urea-based Abeta-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)/immunoblot. In addition to the Abeta peptides 1-37/38/39/40/42, which we recently identified as regular constituents of human cerebrospinal fluid (CSF), we have observed a novel electrophoretic band migrating slightly cathodically to Abeta1-42. Since a standard peptide with the amino acid sequence Abeta2-40 migrates in the same position, we hypothesize that this plasma-specific band may correspond to Abeta2-40. The concentration of Abeta peptides in the plasma has been approximately 100-fold lower compared to the CSF. Interestingly, the concentration of the two shortest peptides and the longest one of these considered here (i.e., Abeta1-37/38/42) have increased significantly when the samples have been frozen at -80 degrees C before immunoprecipitation, while the 'middle-length' peptides (i.e., Abeta1-39/40) have not been affected by this procedure. We have not observed significant differences of the Abeta peptides concentrations between AD and control subjects. Our method can be used to investigate the significance of plasma Abeta peptides in neurodegenerative disorders, and to monitor the efficiency of drugs with beta/gamma-secretase inhibitory potency.     

微量元素医学精要Ⅱ.疾病的诊断和治疗

本文根据微量元素医学的基本理论和方法对疾病进行诊治的进展作了综述。包括以下内容；人体疾病与微量元素。微量元素日供给量，治疗量及食物来源。微量元素分析测试方法简介和人体微量元素参考值。