European journal of clinical chemistry and clinical biochemistry : journal of the Forum of European Clinical Chemistry Societies最新文献

We have measured the bile acids in human serum as methyl ester-trimethylsilyl ethers by gas chromatography-mass spectrometry (GC-MS) using an electron ionization procedure. The overall method was validated and the detection limit (0.4 mumol/l), linearity (2-30 mumol/l), intra-day and inter-day precision, accuracy and recovery (96.2% for nor-23-deoxycholic acid as internal standard) were measured. Serum C24-bile acids profiles from 43 cholestatic patients were measured by GC-MS and by HPLC. The results obtained with the two methods were well correlated and the criteria for selecting either HPLC or GC-MS identified. The serum C24- and C27-bile acids and C29 dicarboxylic bile acid profiles for patients with generalized peroxisomal deficiencies, like Zellweger syndrome (n = 5), neonatal adrenoleukodystrophy (n = 1), infantile Refsum disease (n = 2) and from a single peroxisomal deficiency (n = 1) were also measured by GC-MS.

The presence of Hb variants may cause analytical interference in HbA1c values measured with the HPLC techniques currently used in Italian laboratories. In this study performance of a new HPLC system, (HA-8140, Menarini) was compared with two other traditional HPLC systems (HA-8121, Menarini and Diamat, Bio-Rad). The HA-8140 system detects the Hb variant possibly present in an independent peak. The integration area of such a peak is not computed in the calculation of the percentage value of HbA1c. In this manner the underestimation of values obtained with traditional HPLC systems is avoided.

Several techniques based on different principles have been proposed to measure lipid hydroperoxides. Enzymatic methods are sensitive and can be quite specific but they are subject to interference by inhibitors and not all are stoichiometric. The present work proposes some modifications of the Heath & Tappel (Anal Biochem 1976; 7:184-91) enzymatic method of determination of lipid hydroperoxides in order to standardize and automate it and to meet the analytical criteria required for a biological assay. The proposed new protocol and the automated assay give acceptable within-run and between-run precisions, with coefficients of variation of 3.34% and 5.80%, respectively, at the usual plasma lipid hydroperoxides content. The recovery is 98.7 +/- 4.89%, and the method is linear for a wide range of contents and sensitive (10 mumol/l) enough to measure the plasma lipid hydroperoxides content.

Type I collagen is the main type found in mineralized bone. Specific radioimmunoassay for the cross-linked carboxyterminal telopeptide of type I collagen allows assessing the degradation of type I collagen in serum samples. The aim of the present investigation was to determine the concentration of cross-linked carboxyterminal telopeptide of type I collagen in serum of dietary calcium and vitamin D-deficient rats, a good model disease of decreased formation and mineralization of bone matrix and excessive bone resorption. The studies were carried out on 20 young growing Wistar rats. Serum concentration of the cross-linked carboxyterminal telopeptide of type I collagen was analyzed by the Rat Telopeptide [125I]ICTP Radioimmunoassay Kit obtained from Orion Diagnostica (Finland). The data obtained from biochemical analysis showed increased concentration of the cross-linked carboxyterminal telopeptide of type I collagen in the serum of rats fed a low calcium and vitamin D-deficient diet after 14 days of the experiment. At the end of the experiment (day 21), the concentration of carboxyterminal telopeptide of type I collagen in serum was still elevated in these animals. In conclusion, dietary calcium and vitamin D-deficiency in rats produces hypocalcaemia together with the increased concentration of the cross-linked carboxyterminal telopeptide of type I collagen in serum.

Fatty acid concentrations in plasma and red blood cell phospholipids isolated from paired venous and capillary blood samples were compared and the effect of storage at -20 degrees C was evaluated as well. Plasma fatty acid profiles from venous and capillary blood were found to be comparable and not affected by up to four weeks of storage, while fatty acid profiles of venous and capillary red blood cells were no longer comparable after four weeks. Substantial losses of long-chain polyunsaturated fatty acids were observed in capillary red blood cells. To investigate whether the observed long-chain polyunsaturated fatty acids loss could be prevented, capillary red blood samples were stored for up to one year at -50 degrees C in the presence of the iron-binding agent deferoxamine or the free radical scavenger butylated hydroxytoluene. Both compounds protected the long-chain polyunsaturated fatty acids. Similarly, storage of red blood cell lipid extracts at -50 degrees C for up to one year was not associated with reduced levels of long-chain polyunsaturated fatty acids. In conclusion, the lipid loss from capillary red blood cells can be reduced for at least one year during storage at -50 degrees C with prior addition of either a metal chelating compound or a free radical scavenger, or by preparing lipid extracts of the samples within one week of blood collection.

More than 800 diagnostic laboratories situated throughout the Eur-Asian continent--from the Pacific Coast up to the North Sea littoral--were involved in a common survey of External Quality Assessment (EQA). It consisted of the simultaneous measurement of up to 30 analytes of 'general' clinical chemistry using the same batch of control material. The laboratories were associated in four EQA institutions: SKZL (The Netherlands), OQUASTA (Austria), SEKK (Czech Republic) and BKKSystem (Community of Independent States). The results demonstrated the feasibility of such a large-scale survey and provided a realistic idea about the state-of-the-art of laboratory diagnosis in these countries: Besides some local specific problems, such as poor quality of water or the forced use of reagents and calibrators from different sources, there are general problems hindering an efficient process of 'harmonization' in laboratory medicine, namely, the high methodological dispersion especially in the case of enzymes and of some organic analytes. At the same time there is a potential necessity for more concentrated implementation of internal quality assessment into the routine work of laboratories.

No convincing support has been provided so far for the existence of extrahepatic hepatitis C virus particles that should correspond to the sometimes extremely high concentration of 'HCV-RNA' in serum or plasma. If a naturally occurring HCV-specific DNA were to be found, a concept for at least some phenomena in terms of the pathophysiology of HCV should become conceivable. DNA was extracted from peripheral blood mononuclear cells of eleven healthy, anti-HCV-negative individuals, including five long term blood donors, and cells from different cell lines. DNA was subjected to nested polymerase chain reaction omitting a reverse transcriptase step with primers of the 5'NC as well as part of the core region of HCV. Direct polymerase chain reaction, i.e. without a reverse transcriptase step, revealed HCV-specific sequences in the DNA fraction of peripheral blood mononuclear cells of different origin: healthy anti-HCV negative individuals, furthermore in HeLa and MT2 cells. The fragments found were of expected length as well as of shorter and of longer than expected length with respect to the sequence of the HCV genome framed by the primers applied. The results derived from additional hybridization, restriction endonuclase analysis, and sequencing demonstrated HCV-specific sequences in the expected fragments with both a high degree of homology and deletions, respectively, substitutions, as compared to a prototype strain. However, the longer than expected fragments also contained sequences not specific for HCV.

Automated immunoassay systems should be convenient to handle, flexible and give reliable results. To investigate the extent to which the UniCAP System met the above requirements, compared with the IMMULITE System, we compared the Phadiatop (UniCAP) and AlaTOP (IMMULITE) results of 110 patients with positive clinical diagnoses for inhalant allergy. In addition, we compared food screening test results of 103 patients with a clinical positive diagnosis for food, and 110 test results of controls with negative diagnosis for allergy. Phadiatop had a sensitivity of 96% and a specificity of 92%. AlaTOP had a sensitivity of 86% and a specificity of 94%. For food screening the results were: 75% sensitivity and 82% specificity for fx5 (UniCAP) and 63% sensitivity and 71% specificity for fp5 (IMMULITE). Furthermore, those samples for which the test results which were not in concordance with the clinical diagnosis were tested with the follow-up panel of the different screening tests. For the AlaTOP follow-up we had to use the DPC microplate System (Milenia), because single allergen testing is not yet possible on the IMMULITE System. With regard to sensitivity, the UniCAP specific inhalant allergen tests and the original Phadiatop results showed closer agreement with each other than did the Milenia specific allergen results with the AlaTOP. The specificity of the single inhalant allergen tests was the same for both systems. For food allergy testing the UniCAP System shows closer agreement between the screening and the follow-up results than does the IMMULITE. The hands on time for loading 44 samples was practically the same for both systems, but for the follow-up tests the Milenia System is used next to the IMMULITE. Therefore from a logistical point of view the UniCAP System is more convenient. From these results we conclude that both logistically and clinically UniCAP seems to meet our requirements better than the IMMULITE.