The Use Of Molecular Docking And Spectroscopic Methods For Investigation Of The Interaction Between Regorafenib With Human Serum Albumin (HSA) And Calf Thymus DNA (Ct-DNA) In The Presence Of Different Site Markers

Background: Interactions of drugs with DNA and proteins may modify their biological activities and conformations, which effect transport and biological metabolism of drugs. Objective: In this study the interaction of anticancer drug regorafenib (REG) with calf thymus-DNA (ct-DNA) and human serum albumin (HSA) has been investigated. Methods: Hence, for the first time, it was discovered interaction between REG with DNA and HSA using multispectroscopic, zeta potential measurements and molecular docking method. Results and Discussion: DNA displacement studies showed that REG does not have any effect on acridine orange and methylene blue bound DNA, though it was substantiated by displacement studies with Hoechst (as groove binder). Furthermore, the different concentrations of REG induce slight changes in the viscosity of ct-DNA. Zeta potential parameters indicated that hydrophobic interaction plays a major role in the DNA-REG complex. Results obtained from molecular docking demonstrate that the REG prefers to bind on the minor groove of DNAs than that of the major groove. Binding properties of HSA reveal that intrinsic fluorescence of HSA could be quenched by REG in a static mode. The competitive experiments in the presence of warfarin and ibuprofen (as site markers) suggested that the binding site of REG to HSA was most probably located in the subdomain IIA. Measurements of the zeta potential indicated that REG bound to HSA mainly by both electrostatic and hydrophobic interactions. It was found on docking procedures that REG could fit well into HSA subdomain IIA, which confirmed the experimental results. Conclusion: In conclusion, REG can be delivered by HSA in a circulatory system and affect DNA as potential target.

Effects of Mining Activities on Gerbillus nanus in Saudi Arabia: A Biochemical and Histological Study

Mining can impact the environment, biodiversity, and human health through direct and indirect practices. This study investigated the effects of gold mining on Gerbillus nanus, in relation to organ dysfunction and redox imbalance. Soil samples, Lycium shawii, and G. nanus were collected from a site near a mining plant, and a control site. Soil and L. shawii samples from the mining site showed significantly higher cadmium (Cd), copper (Cu), mercury (Hg), arsenic (As), zinc (Zn), lead (Pb), and vanadium (V) levels. Hepatic, renal, and pulmonary Cd, Pb, Hg, Zn, Cu, Fe, As, and V concentrations were significantly higher in G. nanus from the mining site. Markers of liver and kidney function were elevated in serum, and several histological manifestations were observed in the liver, kidney, and lung of G. nanus from the mining site. Malondialdehyde and nitric oxide levels increased, and glutathione and antioxidant enzymes decreased in the liver and kidney of G. nanus. In conclusion, mining practices trigger tissue damage and oxidative stress in G. nanus that live close to the mining site. These findings can represent a scientific basis for evaluating the environmental and health impacts of mining on nearby communities.

Effects of Mining Activities on Gerbillus nanus in Saudi Arabia; A Biochemical and Histological Study

Mining can impact the environment, biodiversity and human health through direct and indirect practices. This study investigated the effects of gold mining on Gerbillus nanus, pointing to organ dysfunction and redox imbalance. Soil samples, Lycium shawii and G. nanus were collected from a site near a mining planet and a control site. Soil and L. shawii samples from the mining site showed a significant increase cadmium (Cd), cupper (Cu), mercury (Hg), arsenic (As), zinc (Zn), lead (Pb) and vanadium (V). Hepatic, renal and pulmonary Cd, Pb, Hg, Zn, Cu, Fe, As and V concentrations were increased significantly in G. nanus at the mining site. Markers of liver and kidney function were elevated in serum, and several histological manifestations were demonstrated in liver, kidney and lung of G. nanus at the mining site. Malondialdehyde and nitric oxide were increased, and glutathione and antioxidant enzyme were declined in the liver and kidney of G. nanus. In conclusion, mining practices triggered tissue damage and oxidative stress in G. nanus living close to the mining site. These findings can represent the scientific basis for evaluating the environmental and health impact of mining in the on the nearby communities.

Interaction of Mycotoxin Alternariol with Serum Albumin

Alternariol (AOH) is a mycotoxin produced by Alternaria species. In vitro studies suggest the genotoxic, mutagenic, and endocrine disruptor effects of AOH, and an increased incidence of esophageal cancer has been reported related to higher AOH exposure. Human serum albumin (HSA) is the most abundant plasma protein in the circulation, it is able to affect toxicokinetic properties of numerous xenobiotics. HSA forms stable complexes with several mycotoxins, however, the interaction of AOH with albumin has not been examined. In this study, the complex formation of AOH with HSA was tested, employing fluorescence spectroscopy, ultrafiltration, and molecular modeling. Each spectroscopic measurement shows the formation of stable AOH-HSA complexes (K = 4 × 105 L/mol). Investigations with site markers (in spectroscopic and ultrafiltration models) as well as modeling studies suggest that AOH occupies Sudlow’s site I as a high-affinity binding site in HSA. The binding affinity of AOH towards bovine, porcine, and rat albumins was also tested, suggesting that AOH binds to rat albumin with considerably higher affinity than other albumins tested. Our results demonstrate the strong interaction of AOH with serum albumins, suggesting the potential in vivo importance of these interactions.

Interaction of 2′R-ochratoxin A with Serum Albumins: Binding Site, Effects of Site Markers, Thermodynamics, Species Differences of Albumin-binding, and Influence of Albumin on Its Toxicity in MDCK Cells

Ochratoxin A (OTA) is a nephrotoxic mycotoxin. Roasting of OTA-contaminated coffee results in the formation of 2′R-ochratoxin A (2′R-OTA), which appears in the blood of coffee drinkers. Human serum albumin (HSA) binds 2′R-OTA (and OTA) with high affinity; therefore, albumin may influence the tissue uptake and elimination of ochratoxins. We aimed to investigate the binding site of 2′R-OTA (verses OTA) in HSA and the displacing effects of site markers to explore which molecules can interfere with its albumin-binding. Affinity of 2′R-OTA toward albumins from various species (human, bovine, porcine and rat) was tested to evaluate the interspecies differences regarding 2′R-OTA-albumin interaction. Thermodynamic studies were performed to give a deeper insight into the molecular background of the complex formation. Besides fluorescence spectroscopic and modeling studies, effects of HSA, and fetal bovine serum on the cytotoxicity of 2′R-OTA and OTA were tested in MDCK kidney cell line in order to demonstrate the influence of albumin-binding on the cellular uptake of ochratoxins. Site markers displaced more effectively 2′R-OTA than OTA from HSA. Fluorescence and binding constants of 2′R-OTA-albumin and OTA-albumin complexes showed different tendencies. Albumin significantly decreased the cytotoxicity of ochratoxins. 2′R-OTA, even at sub-toxic concentrations, increased the toxic action of OTA.

Which pen? A comparative study of surgical site markers

A preoperative requirement is the correct and clear marking of a specific surgical site. We aimed to compare the ability of marker pens to withstand surgical preparation. Five volunteers with different Fitzpatrick skin types were marked with ten pens. Marked skin sites were prepared with chlorhexidine followed by chlorhexidine, betadine followed by chlorhexidine, and betadine followed by betadine. Each site was photographed in theatre. Two volunteers ranked the top three most visible marker pens from each photograph. The results showed that Sharpie® W10 black, Dual Tip (Purple Surgical), and Easimark modern regular tip (Leonhard Lang) were the best performers across all skin types. Red pen should be avoided with betadine skin preparation. The study concludes that the above named three markers are the best at withstanding surgical skin preparation. Different skin types require different colour ink for maximal clarity in marking. Biro and drywipe markers should never be used for surgical marking.