[Dichlorvos insect strips indoors: pollution and risk assessment]. / Dichlorvos-Insektenstrips in Innenräumen: Belastung und Risikoabschätzung.

Exposure to Danger and Assessing the Hazards: Application of the highly potent pest control agent dichlorvos (DDVP) involves the hazard of effects on the central nervous system and a risk of human cancer. Consumers use dichlorvos in pest strips to protect their rooms from insects. This undifferentiated pest control can lead to chronic exposure. Over several weeks we found an indoor air concentration of dichlorvos between 60 and 1300 micrograms/m3 in 34 m3-experimental-room (chamber). Textiles and foodstuffs in this room were also contaminated. Beside the inhalative intake the oral and dermal intake can also lead to an additional loading of the residents. The ADI-resp. DTA-value of 4 micrograms/kg body-weight and day is exceeded about 10-15 times on the average by inhalative exposure only.

In situ nick translation of human chromosomes using Alu I: unmasking of recognition sites by proteinase K pretreatment.

Human chromosomes prepared according to routine methods were treated with the restriction endonuclease Alu I followed by staining with Giemsa solution or fluorescent dyes. This procedure results in a C-band-like appearance of the chromosomes due to removal of DNA from euchromatic chromosomal regions. The resistance of heterochromatic regions against cleavage by the enzyme has mainly been interpreted by the absence or rareness of recognition sites for this particular enzyme in these regions. Proteinase K pretreatment followed by a nick translation procedure with Alu I was combined to check this hypothesis. The results show that heterochromatic chromosomal regions can also be labelled. Thus, they are not characterized by a lack of recognition sites. Gradual deproteinisation of chromosomes changes the labelling pattern from a reverse C-banding pattern to a C-band-like appearance. The resistance of heterochromatic chromosomal parts revealed by the technique is mainly due to local chromatin configuration rather than to the underlying DNA sequence itself.