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G Zapff

Publications and source records attributed to G Zapff.

4 recordsLinked to original sources
PubMed1989

[A simple method for the quantitative determination of sperm aggregation].

Described in this paper are 2 methodological variants for photometric recording of sperm aggregation. Heparin was used to induce aggregation. One of the working principles was related to aggregation-associated alteration of turbidity in an agitated cell suspension, measured by the KZM-1 coagulation-time meter, in analogy to measurement of thrombocyte aggregation. The 2nd variant was based on variation of cloudiness due to sedimentation of aggregates in a non-agitated suspension. Both methods provided equally valid information. They characterised both intensity of aggregation as a combined effect of the number and size of aggregates as well as the rate of aggregation. Photometric recording has proved to be an objectivated method for quantitative assessment of aggregation. Its use is proposed for studies into capacitation or immunological response of spermatozoa.

Animals↗
PubMed1988

[Results (in vitro and in vivo) of cryopreservation of human thrombocytes with glycerol].

The cryopreservation of human platelets was carried out with a final glycerol concentration of 0.38-0.48 mol/l (3.5-4.5%). The in-vitro-recovery (total platelets, aggregation, 14C-5-HT-uptake, clot retraction, total ATP, morphology) was in the range of 35-93% in comparison with freshly prepared platelet concentrates. The platelet survival was investigated by 51chrom labeling and autologous transfusion. A survival rate of 42% and a mean survival of 79% in comparison with freshly prepared platelets is concentrates are the results. In spite of reduced viability the cryopreservation of platelets is invaluable for providing compatible platelets for alloimmunized patients.

Blood Platelets↗
PubMed1981

[Gas-chromatographic determination of chloramphenicol residues in animal material].

On the basis of the relevant literature and of their own experimental work, the authors describe extraction, cleaning and derivatization procedures for the determination of chloramphenicol in milk, muscular substance, urine and bile. Chloramphenicol was determined as bis-(trimethylsilyl)-ether using a gas chromatograph fitted with an electron capture detector. To evaluate the analytical techniques, the authors estimated the sensitivity, accuracy and precision for residue amounts of 0.1 and 0.05 mg of chloramphenicol/kg of material under investigation. The limit of detection was 0.02 mg/kg for meat, and 0.01 mg/kg for milk, urine and bile.

Animals↗