Journal of clinical chemistry and clinical biochemistry. Zeitschrift fur klinische Chemie und klinische Biochemie最新文献

Preservation of blood glucose is better with added D-mannose than with added sodium fluoride. Nearly complete preservation can be achieved by the use of both D-mannose and sodium fluoride.

In order to assess the burden of environmental pollutants in the genital tract, 12 different chlorinated hydrocarbons were determined in 152 samples of follicular, seminal and cervical fluids from sterility patients in the in vitro fertilization programme at the Centre for Obstetrics and Gynaecology of the University of Bonn. The lowest concentrations were found in the follicular fluids of patients who eventually became pregnant by in vitro fertilization. Higher concentrations were found in patients with sterility of unknown origin. Concentrations in the cervical secretion were up to twenty times higher than those in the seminal or follicular fluids. The results show that considerable concentrations of chlorinated hydrocarbons may be present in parts of the reproductive system, and that these compounds accumulate in the reception zone for spermatozoa. Certain pollutants therefore probably contribute to infertility.

A technique for the reproducible re-use of antibody-coated solid phases for immunoassays is described. The method based on the dissociation of the antigen-antibody complexes. Two different procedures, using glycine buffer (pH 2.3) or ethanolamine, were developed. More than ten immunoassay cycles can be realized with the same antibody-coated microtitre plates. These procedures were tested with competitive and sandwich immunoassays, monoclonal and polyclonal antibodies, and a commercial immunoassay kit.

Severe tissue carnitine deficiency impairs fatty acid oxidation. In explanted hearts from patients with end stage heart failure a 57% carnitine decrease was found in comparison with healthy donor hearts (p less than 0.05). The reduction of myocardial carnitine levels affected all areas of the explanted hearts to a comparable extent. Carnitine decreases in patients with dilated cardiomyopathy or coronary artery disease were similar. Endomyocardial biopsies from patients with less severe heart failure due to cardiomyopathy (n = 28) or other myocardial diseases (n = 8) showed a 42% decrease of total myocardial carnitine (in nmol/mg non-collagen protein) in comparison with biopsies from patients with normal cardiac function (controls) (heart failure: 5.7, confidence interval 4.2-7.0; controls 9.3, confidence interval 7.6-12.0, p less than 0.005). Free myocardial carnitine in heart failure was also different from controls (heart failure: 4.2, confidence interval 3.7-5.3; controls 10.3, confidence interval 7.5-12.2, p less than 0.001). The decrease of free and total myocardial carnitine was comparable in dilated cardiomyopathy and heart failure due to other diseases. Alterations in myocardial carnitine content represent therefore non-specific biochemical markers in heart failure with yet unknown consequences for myocardial function.

Due to the high reactivity of the chemical species and the presence of multiple potentially interfering substances, the measurement of oxygen-derived free radicals in biological material requires highly developed techniques. The currently employed methods are reviewed according to the reactions upon which they are based, the assays, possible interferences and their use in medical research. Detection of the emission of light is a very popular method. Although it is in principle unspecific, there are modifications to measure individual radical species. The only direct way to detect radicals is electron spin resonance spectroscopy. Among the specific assays for O2- the reductions of nitroblue tetrazolium or cytochrome c are predominant. For the detection of H2O2 different techniques are employed for either intracellular or extracellular determination. An array of substances has been used for the measurement of OH. Which of them is the most useful depends on the question to be answered. There are also indirect methods that determine free radicals based on chemical modifications caused by them; the most important assays of this kind quantify lipid peroxides. In addition, assays for thiobarbituric acid-reactive substances and DNA strand breaks and interstrand crosslinks are used.

The plasma level of carnitine, a co-factor involved in many metabolic reactions, is high in alcoholic liver cirrhosis, due to an increased amount of esterified carnitine. To determine if this alteration is linked to alcoholic liver disease or to liver cirrhosis per se. total carnitine, free carnitine, total esterified carnitine, short chain acylcarnitine and long chain acylcarnitine were measured in 41 patients suffering from liver cirrhosis of different aetiology and severity. In 19 of these patients, acetylcarnitine was also measured. Moreover, multivariate analysis was performed to assess the association of carnitine plasma levels with nutritional and liver disease indices. Of the nutritional indices (creatinine/height ratio, mid upper arm muscle circumference and triceps skinfold) only triceps skinfold appeared to be weakly correlated with carnitine (with long chain acylcarnitine). Significantly high levels of acetylcarnitine, short chain acylcarnitine, total esterified carnitine and total carnitine were found in cirrhotics independently of the aetiology of cirrhosis, even though a trend towards higher levels of acetylcarnitine was evident in heavy drinkers. Direct correlations of gamma-glutamyltransferase with acetylcarnitine, acetylcarnitine/free carnitine, short chain acylcarnitine/free carnitine and total esterified carnitine/free carnitine were found. Carnitine plasma levels did not differ in the three Pugh-Child's classes; however, a trend towards higher levels of acetylcarnitine was found in Pugh-Child's class C. In conclusion, the high levels of acetylcarnitine, short chain acylcarnitine, total esterified carnitine and total carnitine found in cirrhosis were linked to liver disease. Alcohol abuse seemed only to be an exacerbating factor.

An improved assay for quantification of urinary porphyrins by use of second-derivative spectroscopy is described. A new method for calculation of the porphyrin concentration is developed and the whole procedure is computerized. Acidified urine samples can be assayed within a few minutes by using this method. Precision and recoveries for both uro- and coproporphyrin are good. The method is presented as a very fast and accurate assay for the screening and quantification of urinary porphyrins.