Investigation of Pseudomonas aeruginosa Biofilm Formation and Quorum Sensing Genes in Piperacillin/Tazobactam and Ciprofloxacin Sub-minimal Inhibitory Concentrations

Pseudomonas aeruginosa is a non-fermentative, oxidase-positive, motile gram-negative bacillus widespread in nature. The virulence factors of P.aeruginosa including the ability to grow under minimal growth conditions, the widespread presence in nature, and the ability to form biofilms make P.aeruginosa a highly important bacterium along with its resistance mechanisms against many antibiotics. The ability to form biofilms increases the symptom severity in diseases caused by P.aeruginosa and causes difficulties in the treatment. The aim of this study was to investigate the effects of sub-minimal inhibitory concentrations (sub-MIC) of piperacillin/tazobactam (TZP) and ciprofloxacin (CIP) which are used for the treatment of P.aeruginosa infections on biofilm formation and to investigate the relationship between the severity of biofilm formation and Quorum Sensing (QS) genes. The study included 24 P.aeruginosa isolates from the culture collection of Medical Microbiology Laboratory of Gazi University Faculty of Medicine. MIC values of TZP and CIP antibiotics were determined by the microdilution method. The biofilm layers in the antibiotic-free medium and in the sub-MIC (MIC/2, MIC/4 ve MIC/8) concentrations of antibiotics were visualized by using a scanning electron microscope (SEM). The QS genes (lasl, lasR, rh/I, and MIR) of the 24 isolates with known biofilm characteristics were identified via the amplification of chromosomal DNA by using PCR method. In the study, it was foundthat both antibiotics reduced biofilm formation in a dose-dependent manner in sub-MIC concentrations compared to the antibiotic-free condition and that MIC/2 was the concentration, which reduced the biofilm formation most. These results were further confirmed by viewing the SEM images. The QS genes lasl, lasR, and Mil were detected in a total of 19 isolates with moderately strong and strong biofilm formation, the rh/R gene was detected in six of the strong biofilm-forming isolates, in four of the moderately strong biofilm-forming isolates, and in three of the weak biofilm-forming isolates, respectively. The investigation of the effects of sub-MIC concentrations of antimicrobials, used for the treatment of P.aeruginosa infections, on the biofilm formation of P.aeruginosa and the investigation and better understanding of the QS systems associated with biofilm production will allow for finding out new treatment approaches and offer different options in combating infections with high morbidity and mortality

Collagen Microarchitecture of the Human Septum Cartilage

Yavuzer, Reha/0000-0002-8549-0875WOS: 000316676300148PubMed: 23524791

Loofah Sponge as an Interface Dressing Material in Negative Pressure Wound Therapy: Results of an In Vivo Study

Since the introduction of negative pressure wound therapy (NPWT), the physiological effects of various interface dressing materials have been studied. The purpose of this experimental study was to compare the use of loofah sponge to standard polyurethane foam or a cotton gauze sponge. Three wounds, each measuring 3 cm x 3 cm, were created by full-thickness skin excision on the dorsal sides of 24 New Zealand adult white rabbits. The rabbits were randomly divided into four groups of six rabbits each. In group 1 (control), conventional saline-moistened gauze dressing was provided and changed at daily intervals. The remaining groups were provided NPWT dressings at -125 mm Hg continuous pressure. This dressing was changed every 3 days for 9 days; group 2 was provided polyurethane foam, group 3 had conventional saline-soaked antimicrobial gauze, and group 4 had loofah sponge. Wound area measurements and histological findings (inflammation, granulation tissue, neovascularization, and reepithelialization) were analyzed on days 3, 6, and 9. Wound area measurements at these intervals were significantly different between the control group and study groups (P <0.05). Granulation and neovascularization scores were also significantly different between the control and treatment groups at day 3 (P = 0.002). No differences in any of the healing variables studied were observed between the other three dressing materials. According to scanning electron microscopy analysis of the three interface materials, the mean pore size diameter of foam and gauze interface materials was 415.80 +/- 217.58 mu m and 912.33 +/- 116.88 mu m, respectively. The pore architecture of foam was much more regular than that of gauze. The average pore size diameter of loofah sponge was 736.83 +/- 23.01 mu m; pores were hierarchically located - ie, the smaller ones were usually peripheral and larger ones were central. For this study, the central part of loofah sponge was discarded to achieve a more homogenous structure of interface material. Loofah sponge study results were similar to those using gauze or foam, but the purchase price of loofah sponge is lower than that of currently available interface dressings. More experimental, randomized controlled studies are needed to confirm these results

The Effects of Riluzole on Cisplatin-induced Ototoxicity

Introduction Riluzole (2-amino-6-trifluoromethoxy benzothiazole) is known as a neuroprotective, antioxidant, antiapoptotic agent. It may have beneficial effects on neuronal cell death due to cisplatin-induced ototoxicity. Objective To evaluate the effect of riluzole on cisplatin-induced ototoxicity in Guinea pigs. Methods Twenty-four Guinea pigs, studied in three groups, underwent auditory brainstem response evaluation using click and 8 kHz tone burst stimuli. Subsequently, 5 mg/kg of cisplatin were administered to all animals for 3 days intraperitoneally (i.p.) to induce ototoxicity. Half an hour prior to cisplatin, groups 1, 2 and 3 received 2 ml of saline i.p., 6 mg/kg of riluzole hydrochloride i.p., and 8 mg/kg of riluzole hydrochloride i.p., respectively, for 3 days. The auditory brainstem responses were repeated 24 hours after the last drug administration. The cochleae were analyzed by transmission electron microscopy (TEM). Results After drug administiration, for 8,000 Hz stimulus, group 1 had significantly higher threshold shifts when compared with groups 2 (p 0.05). Transmission electron microscopy findings demonstrated the protective effect of riluzole on the hair cells and the stria vascularis, especially in the group treated with 8 mg/kg of riluzole hydrochloride. Conclusion We can say that riluzole may have a protective effect on cisplatin- induced ototoxicity. However, additional studies are needed to confirm these results and the mechanisms of action of riluzole. Copyright © 2019 by Thieme Revinter Publicações Ltda, Rio de Janeiro, Brazi

Could nephrotoxicity due to colistin be ameliorated with the use of N-acetylcysteine?

WOS: 000286194400017PubMed ID: 20845026The protective effect of N-acetylcysteine (NAC) on nephrotoxicity due to contrast nephropathy and reperfusion-induced ischemia has been reported in experimental models. However, its efficacy on colistin-induced nephrotoxicity has not been elucidated yet. The primary aim of this study was to evaluate the nephrotoxic effect of colistin and to investigate the possible protective effect of NAC on colistin-induced nephrotoxicity. The secondary aim was to research the systemic effects of nephrotoxicity-induced oxidative stress on the lung. Eighteen female Sprague-Dawley rats were randomly assigned and were given (a) 1 ml/kg sterile saline, (b) 300,000 IU/kg/day colistin, and (c) 300,000 IU/kg/day colistin and 150 mg/kg NAC for six consecutive days. Plasma blood urea nitrogen (BUN), creatinine, urinary creatinine, urinary protein, plasma TNF-alpha levels, renal tissue superoxide dismutase (SOD) and malondialdehyde (MDA) activity and immunocytochemical findings were evaluated. Colistin exerted nephrotoxicity and achieved a significant increase in plasma BUN and creatinine levels and renal tissue SOD levels. NAC exhibited no significant effect on biochemical parameters but reduced renal tissue SOD level and reversed immunocytochemical staining of inducible nitric oxide synthase (i-NOS) and neurotrophin-3. Increased oxidative stress in the lung tissue of the rats treated with colistin has also been documented. Additionally, NAC significantly reduced the immunostaining of endothelial NOS (e-NOS) and i-NOS in the lung tissue. Colistin-induced renal toxicity may be attributable to oxidative damage. The combined treatment of colistin plus NAC seems to have a beneficial role in restoration of the oxidant injury which may be related to its antioxidant effect.Internal Medicine Postgraduate Education Society (IMSED)The authors do not have any personal relationships to disclose which may affect the present work. The study was supported by a grant from the Internal Medicine Postgraduate Education Society (IMSED)

Is there Any Link Between Oxidative Stress and Lung Involvement due to Inflammatory Bowel Disease: An Experimental Study

WOS: 000300532700010PubMed ID: 22234058Background/Aims: Lung involvement due to inflammatory bowel disease (IBD) is frequent, however the pathogenic mechanism is still debatable. Although the evidence of inflammation in colonic and lung tissue has been documented, the possible effect of oxidative stress in lung tissue has not been evaluated to date. We sought to assess the effects of oxidant/antioxidants on lung tissue in a model of experimental colitis. Methodology: Colitis was induced with intra-colonic administration of 4% acetic acid. Control group received isotonic saline. Serum and lung tissue markers of oxidative stress were explored. Results: Serum total oxidant status was significantly higher in the colitis group than the controls while total antioxidant status was similar. The determinants of oxidants including lipid peroxidation assay and myeloperoxidase activity were significantly higher in the lung tissue of the colitis group whereas the indicators of antioxidant capacity determined as superoxide dismutase, catalase, glutathione and glutathione peroxidase were decreased (p<0.05). Conclusions: This study showed that oxidative stress is not restricted to the bowel and the lung is a main target of oxidant overload. Pulmonary injury caused by increased oxidant stress may be the underlying reason of pulmonary involvement due to IBD

Melatonin Modulates NMDA-Receptor 2B/Calpain-1/ Caspase-12 Pathways in Rat Brain After Long Time Exposure to GSM Radiation.

To investigate the potential protective effects of melatonin on the chronic radiation emitted by third generation mobile phones on the brain

Neuroprotective effects of melatonin upon the offspring cerebellar cortex in the rat model of BCNU-induced cortical dysplasia

WOS: 000248658500014PubMed ID: 17572393Cortical dysplasia is a malformation characterized by defects in proliferation, migration and maturation. This study was designed to evaluate the alterations in offspring rat cerebellum induced by maternal exposure to carmustine-[1,3-bis (2-chloroethyl)-1-nitrosoure] (BCNU) and to investigate the effects of exogenous melatonin upon cerebellar BCNU-induced cortical dysplasia, using histological and biochemical analyses. Pregnant Wistar rats were assigned to five groups: intact-control, saline-control, melatonin-treated, BCNU-exposed and BCNU-exposed plus melatonin. Rats were exposed to BCNU on embryonic day 15 and melatonin was given until delivery. Immuno/histochemistry and electron microscopy were carried out on the offspring cerebellum, and levels of malondialdehyde and superoxide dismutase were determined. Histopathologic ally, typical findings were observed in the cerebella from the control groups, but the findings consistent with early embryonic development were noted in BCNU-exposed cortical dysplasia group. There was a marked increase in the number of TUNEL positive cells and nestin positive cells in BCNU-exposed group, but a decreased immunoreactivity to glial fibrillary acidic protein, synaptophysin and transforming growth factor beta 1 was observed, indicating a delayed maturation, and melatonin significantly reversed these changes. Malondialdehyde level in BCNU-exposed group was higher than those in control groups and melatonin decreased malondialdehyde levels in BCNU group (P<0.01), while there were no significant differences in the superoxide dismutase levels between these groups. These data suggest that exposure of animals to BCNU during pregnancy leads to delayed maturation of offspring cerebellum and melatonin protects the cerebellum against the effects of BCNU. (C) 2007 Elsevier B.V. All rights reserved