Zeitschrift fur medizinische Laboratoriumsdiagnostik最新文献

Sialic acid is an acute phase reagent with tumour burden reflecting fluctuations of serum level. The parameter is unsuitable for an early recognition of cancer. Sialic acid could be used as a parameter in questions concerning tumour burden: the diagnosis of tumour stage, the control of growth after therapy, the prediction of recidivation. The small specificity of an increased serum level of sialic acid will presumably be only of little use in tumour diagnostics.

Determination of peripheral lymphocytes has increasing importance in laboratory examinations. However, evidence concerning differential diagnosis is low. For experimental questions and therapeutical monitoring application of this method is more distributed. This paper transfers practical experiences concerning the detection of cellular surface antigens. For the investigations, monoclonal antibodies from the Karl-Marx-University Leipzig were used in immunofluorescence microscopy. Limits of the test are demonstrated (in skin diseases and HIV-infection f.e.).

Filterability measurements have been used widely in medical research and clinical practice to characterize erythrocyte deformability. In the present paper the influence of white blood cells (WBC) on the of filterability indices is investigated and discussed. We found for two gravity filtration systems using cellulose filters and concentrated erythrocyte suspensions sensitivities of their filterability indices of 1% per 100 WBC/microliters (initial) filtration rate measurement) and 3% per 100 WBC/microliters (hemofiltrometer). The necessity, advantages and disadvantages of additional methods for WBC removal are discussed in comparison to nuclepore filtration systems with sensitivities of 5-12% per 100 WBC/microliters. The standardization of residual WBC-count in limits of 500 +/- 300 WBC/microliters at a hematocrit of 60% is proposed.

The "VEB Filmfabrik Wolfen" offers a textile material for sale, which is well suited for manufacturing of ultrathin reinforced polyacrylamide gels. In contrast to the glass- or polyester-stabilized gels such fabric-reinforced gels allow diffusion- or electroblotting methods. First experiences with ultrathin SDS- and IEF-gels, manufactured using this new supporting material are represented.

Thin layer urea isoelectric focusing is a powerful tool for a rapid and reproducible high resolution separation of cholecystokinin stimulated human pancreatic proteins. In pancreatic juice of patients without pancreatic disease, 11 main protein bands were separated and distinguished by Coomassie Blue-R 250 staining. A number of faint protein bands divided among the whole pH range demonstrate a wide microheterogeneity of exocrine pancreatic proteins. Secretory protein patterns of patients with chronic pancreatitis are shown to be different from those of patients without pancreatic disease. Significant alterations were found at the acidic protein band region of pI 4.4 to 4.7. In two cases of chronic pancreatitis the IEF pattern was very similar to that obtained by a short time enteropeptidase incubation of pure pancreatic juice from patients without pancreatic disease.

A computer-controlled freezing apparatus is described which uses liquid nitrogen (LN2) as coolant. The freezing equipment BF 80 consists of a big cryochamber (volume 24 l), a LN2 tank and a computer for the control of the freezing procedure. The biofreezer functions in the range from 40 to -180 degrees C. A complete cooling curve can be composed of up 15 linear segments with freezing rates between 0 and 45 K.min-1. In the computer up to 80 different freezing curves can be stored and activated by simple operations. The reliability of the biofreezer BF 80 was successfully tested for the cryopreservation of lymphocytes.

3,3' 5,5'-tetramethylbenzidine (TMB) is a high sensitive chromogenic substrate for horseradish-peroxidase as a marker enzyme. In an enzyme immunoassay (EIA) for alpha-1-fetoprotein and in an rapid EIA for myoglobin it reveals higher sensitivity compared to o-phenylenediamine, the increase depends on reaction time. The optimal peroxide concentration depends on reaction time of enzyme chosen in different assays. TMB used for histochemistry is also suitable for EIA if hydrochloric acid is used as stopping reagent. TMB lacks in mutagenic properties and it should preferred for peroxidase rather than all other chromogenic substrates applied up to now.

For the routine subtyping of PGM1 isozymes by means of agarose gel thin-layer electrophoresis, a tris-maleic acid-buffer and an acetic acid-buffer, several agaroses with electroendosmosis up to -0, 16, and several papers are tested. With all these materials good results can be obtained, so that agarose without electroendosmosis is not necessary and FN 1 papers can be used.