The effects of peracetic acid solution on the treatment of otomycosis in an animal model: a new antifungal drug?

OBJECTIVE: This study aimed to investigate the therapeutic effects of 1 per cent and 0.01 per cent peracetic acid as an antifungal agent in animal otomycosis. METHOD: After creating a superficial scratch in the external auditory canal of guinea pigs, a suspension of Aspergillus niger, Aspergillus fumigatus and candida were inoculated into the ears of the animals. After otomycosis, the effect of 1 per cent or 0.01 per cent peracetic acid on otomycosis was evaluated by otomicroscopy and culture at 10 days post-treatment and compared with 2 per cent acetic acid as the control. RESULTS: A 10-day treatment with 1 per cent peracetic acid and 2 per cent acetic acid (control) showed normal otomicroscopy and negative cultures compared with 0.01 per cent peracetic acid. Drug sedimentation or other side effects in the external auditory canal or tympanic membrane were not observed during treatment with peracetic acid. CONCLUSION: The findings of this study confirm that the treatment of otomycosis with 1 per cent peracetic acid in an animal model is beneficial and may be a novel therapeutic treatment for otomycosis.

Feasibility of using a single MRI acquisition for fiducial marker localization and synthetic CT generation towards MRI-only prostate radiation therapy treatment planning.

Purpose.To investigate the feasibility of using a single MRI acquisition for fiducial marker identification and synthetic CT (sCT) generation towards MRI-only treatment planning for prostate external beam radiation therapy (EBRT).Methods.Seven prostate cancer patients undergoing EBRT, each with three implanted gold fiducial markers, participated in this study. In addition to the planning CT scan, all patients were scanned on a 3 T MR scanner with a 3D double-echo gradient echo (GRE) sequence. Quantitative susceptibility mapping (QSM) was performed for marker localization. QSM-derived marker positions were compared to those from CT. The bulk density assignment technique for sCT generation was adopted. The magnitude GRE images were segmented into muscle, bone, fat, and air using a combination of unsupervised intensity-based classification of soft tissue and convolutional neural networks (CNN) for bone segmentation.Results.All implanted markers were visualized and accurately identified (average error: 0.7 ± 0.5 mm). QSM generated distinctive contrast for hemorrhage, calcifications, and gold fiducial markers. The estimated susceptibility/HU values on QSM/CT for gold and calcifications were 31.5 ± 2.9 ppm/1220 ± 100 HU and 14.6 ± 0.9 ppm/440 ± 100 HU, respectively. The intensity-based soft tissue classification resulted in an average Dice score of 0.97 ± 0.02; bone segmentation using CNN resulted in an average Dice score of 0.93 ± 0.03.Conclusion.This work indicates the feasibility of simultaneous fiducial marker identification and sCT generation using a single MRI acquisition. Future works includes evaluation of the proposed method in a large cohort of patients with optimized acquisition parameters as well as dosimetric evaluations.

Correlation between nitrogen fixation rate and alginate productivity of an indigenous Azotobacter vinelandii from Iran.

BACKGROUND AND OBJECTIVES: Azotobacter vinelandii, a gamma-proteobacterium, is an obligate aerobic free-living gram-negative soil bacterium capable of fixing nitrogen. Oxygen transfer rate into the cell is reduced by the increase of alginate concentrations during the course of A. vinelandii cultivation. This phenomenon provides a low intracellular oxygen concentration needed for nitrogenase activity. The aim of this study was to design a simple strategy to explain the alginate production, cell growth and nitrogenase activity correlation in A. vinelandii under aerobic conditions. MATERIAL AND METHODS: Thirty-five different soil samples were taken from the rhizosphere of agricultural crops of Iran. Enrichment and isolation strategies were employed for microbial isolation. Physiological and biochemical characteristics were determined. Molecular identification was performed using selective nifH-g1 primers. Alginate production and nitrogenase activity assay by each isolate of Azotobacter were carried out. Bacterial growth, alginate production and Nitrogenase activity were conducted by time-coursed quantitative measurements. RESULTS: Total of 26 isolates were selected after enrichment, isolation, and screening. The isolate was identified by molecular tests as A. vinelandii. The highest alginate productions of 1.02 g/l and 0.91g/l were noted after 4 days in 8 isolates, cell biomass of which were estimated 4.88-5.26 g/l. Six of 8 isolates were able to fix atmospheric N(2) on nitrogen-free medium. Rates obtained in isolates were in the range of 12.1 to 326.4 nmol C(2)H(4) h(-1) vial(-1). CONCLUSIONS: Nitrogen fixation and alginate production yielded significant and positive Pearson's correlation coefficient of R(2) = 0.760, p ∼ 0.02. Finally association between bacterial growth, alginate production and nitrogenase activity almost noticeable yielded significant and positive Pearson's correlation coefficient R2= 0.723, p ∼ 0.04.