[Dr. Wang's tube--study of a new technique for eliminating pathogens in sperm preparation for reproductive medicine]

A total of 30 ejaculates has been tested for ejaculate volume, spermatozoal concentration, motility, agglomeration, agglutination and contamination by microorganisms. After that the ejaculate has been washed twice and transferred in the Dr. Wangs Tube which was filled with medium before. After an incubation time of 90 minutes very quickly moving spermatozoan could be observed through the microscope in the upper part (C-D) of the Tube. After the Tube was cut by means of a special glasscutter the motility of the containing spermatozoans of part C-D has been determined again, followed by a second bacteriological examination of the so prepared ejaculate. The results of sperm preparation with the Dr. Wangs Tube regarding the sperm motility has been very good (85.7% of the sperm samples showed a motility rate of 90% or even more after treatment). The bacteriological examination has been satisfactory: in 77.7% of the cases all existing sperm bacterias has been eliminated by preparation in the Dr. Wangs Tube. Among other microorganisms Escherichia coli, Proteus mirabilis and Staphylococcus aureus which are considered to be pathologic could be isolated from five of the ejaculates and have been removed after treatment with the Dr. Wangs Tube. The handling of the Tube was rather demanding and Technically problematic. There has been caused glass-splinters by cutting the Tube which got visible while observing the ejaculate-medium-liquid through the microscope. Their sizes were nearly equivalent to the size of a sperms head or even bigger. If the so prepared ejaculate would be used for insemination and in-vitro fertilisation the very small splinters may destroy the success of the treatment and should be avoided or removed. The Dr. Wangs Tube offers a new modified swim-up technique for sperm preparation and is able to produce a high quality, nearly sterile sperm sample. Because of the technical deficiency of the system, the high purchase and running costs and the very small output (sperm sample volume, number of spermatozoans) the Dr. Wangs Tube is not be recommended for the reproductive medicine in its present shape.