1.3.3 Methods of the measurement of DNase activity In 1950, the first method of the measurement of DNase I activity was described by Kunitz196. He isolated and precipitated DNase from fresh beef pancreas and isolated thymus nucleic acid. He found that the cleavage of DNA by crystalline DNase is accompanied by increase of absorption (at 260 nm) of UV light. This spectrophotometric method of measurement of the rate of the increase in the light absorption was then used for estimating of DNase activity. It lasted 43 years until in 1993 Nadano et al. introduced a new method for DNase I activity measurement called “single radial enzyme diffusion” or SPRED (Fig.8). This method is simple and it is based on the digestion of DNA in the agarose gel by …show more content…
Airways of the people with cystic fibrosis and chronic obstructive pulmonary disease are characterized by high levels of DNA209 and actin210 in the lung lumen. These particles are released by necrotic neutrophils211 but also by NETosis212. Increased viscosity of mucus leads to a decreased mucociliary clearance. Several studies have therefore addressed the use of DNase as a possible treatment. In 1950, Armstrong and White showed that rhDNase decreased the viscosity of mucus in vitro within minutes213. Since then, the positive effects of DNase treatment were studied at the different types of respiratory system diseases, such as cystic fibrosis214, asthma, obstructive pulmonary disease, chronic pulmonary …show more content…
Sugihara el al. in several studies showed that DNase treatment prevents blood-borne liver metastasis of cutaneously transplanted tumour cells in mice and also ascites tumour cells in rats. The same research team then showed that the intravenous administration of DNase I enhanced tumor-cell arrest in the lung microvasculature225–227. Linardou et al. tested the cytotoxic potential of mammalian DNase-I and its possible use in tumour-targeting strategies for cancer therapy. They designed the anti-PLAP scFv-DNase-I chimera, which was highly cytotoxic in vitro in cells expressing the PLAP antigen. Then, in 2003, Ben-Yehudah et al. constructed and characterized a new chimeric protein, GnRH-DFF40, consisting of caspase-activated DNase. This protein construct exhibited the DNase I activity and was able to target and kill adenocarcinoma cells228. The next study showed the high sensitivity and reduction in the proliferation of tumor cells to the presence of DNase