It is generally assumed that nucleic acids are localized inside of living cells and that their primary function is the storage of information. In contrast, extracellular DNA is mainly considered as a remnant of lysed cells. Here, we report the formation of extracellular bacterial DNA as a spatial structure. An aquatic bacterium, strain F8, was isolated, which produced a stable filamentous network of extracellular DNA. Different staining and enzymatic techniques confirmed that it was DNA. We were able to amplify the 16S rRNA gene from the extracellular DNA. Restriction endonuclease cleavage and randomly amplified polymorphic DNA analysis of extracellular and genomic DNAs revealed major similarities, but also some differences in both sequences. Our data demonstrate a new function and relevance for extracellular DNA.

The use of 29-G compared with 25-G Quincke needles led to no reduction of PDPH and is considerably higher compared with data from pencil-point needles. The use of non-cutting or pencil-point spinal needles should become the standard for performing spinal saddle block.

ISRCTN41981381 (http://www.controlled-trials.com).

These data prove that using 27-G PP needles is the method with the fewest side effects caused by spinal saddle block, and suggest that the time spent sitting in the upright position is not clinically relevant.

Both from reasons of practicability and from patients' view, spinal anaesthesia in saddle block technique can be thoroughly recommended for transanal surgery. Patients undergoing a stapler haemorrhoidectomy should receive additional opioids.