Oxidative Stress in Urolithiasis

Oxygen is absolutely essential for the survival of our life. However, metabolic consumption of oxygen inevitably yields reactive oxygen species (ROS). Imbalance of ROS production and antioxidant capacity causes oxidative stress that potentially damages biomolecules leading to cell injury and death. In fact, ROS have two-faceted functions. Under physiologic condition, ROS function as signaling molecules and participate in maintaining redox balance. In pathology, ROS induce oxidative stress that critically involves in the development of several diseases including urolithiasis (UL). UL or urinary stone disease is a common urologic condition in all countries with progressively increasing prevalence. Most of UL are multifactorial with polygenic susceptibility and highly recurrent nature. Formation of urinary stones is driven by supersaturation of urinary lithogenic ions, and calcium oxalate (CaOx) is the most prevalent stone type. Oxidative stress clearly plays an active role in UL development. In vitro lithogenic crystals induce ROS generation in renal tubular cells leading to oxidative stress, cell injury and release of inflammatory mediators. In nephrolithic rats, oxidative stress and CaOx deposit are gradually increased in the rats’ kidneys. Intervention with antioxidants efficiently reduces oxidative damage and crystal deposits. Human studies show that patients with UL have increased oxidative stress and renal tubular injury relative to the non–stone-forming individuals. Increased oxidative lesions and inflammation are observed in the stone-containing kidneys of the patients. Furthermore, renal fibrosis mediated through tubular epithelial-mesenchymal transition is observed in kidneys of stone patients. Increased renal fibrosis is significantly associated with decreased kidney function. From therapeutic point of view, nutraceutical regimens that are able to reduce oxidative stress may be clinically useful alternatives for preventing stone formation and recurrence. This chapter has an intention to provide a basic knowledge of ROS generation and oxidative stress and up-to-date research findings of oxidative stress in UL based on the published articles as well as the author’s studies

Detection of CD33 expression on monocyte surface is influenced by phagocytosis and temperature

CD33 is a myeloid-associated marker and belongs to the sialic acid-binding immunoglobulin (Ig)-like lectin (Siglec) family. Such types of receptors are highly expressed in acute myeloid leukemia, which could be used in its treatment. CD33 shows high variability in its expression levels with still unknown reasons. Here, we investigated the CD33 expression of monocytes in human blood samples processed at different temperatures and in dependence on their phagocytic activity against opsonized Escherichia coli. The samples were stained by fluorescently labelled anti-human CD14 to specify the monocyte population, anti-human CD33 antibodies to evaluate CD33 expression and analyzed by flow cytometry and confocal laser scanning microscopy. In blood samples kept at 37°C or first pre-chilled at 0°C with subsequent warming up to 37°C, the percentage of CD33-positive monocytes as well as their relative fluorescence intensity was up-regulated compared to samples kept constantly at 0°C. After exposure to E. coli the CD33 relative fluorescence intensity of the monocytes activated at 37°C was 3 to 4 times higher than that of those cells kept inactive at 0°C. Microscopic analysis showed internalisation of CD33 due to its enhanced expression on the surface followed by engulfment of E. coli

Genetic characterization of coliform bacterial isolates from environmental water in Thailand

Introduction: In contrast to the study in other part of the world, information about characteristics of plasmids carrying antimicrobial resistance genes (ARGs) in Enterobacteriaceae derived from environmental water in tropical Asian countries including Thailand is limited. This study, therefore, aimed to gain insight into genetic information of antimicrobial resistance in environmental water in Thailand. Methods: Coliform bacteria were isolated from environmental water collected at 20 locations in Thailand and identified. Then, susceptibility profiles to ampicillin, cefazoline, cefotaxime, kanamycin, ciprofloxacin, sulfamethoxazole, tetracycline, and nalidixic acid were assessed. In addition, antimicrobial resistant genes integrons, and replicon types were analyzed. And furthermore, plasmids carrying bla(TEM) and tetM were identified by S1-PFGE analysis and confirmed transmissibility by transconjugation experiments. Results: In 130 coliform bacteria isolated, 89 were resistant to cefazoline while 41 isolates were susceptible. Cefazoline-resistant coliform bacteria were found to be significantly resistant to cefotaxime and tetracycline as compared to susceptible isolates. Hence, blaTEM and tetM correlating with beta-lactam antibiotics and tetracycline, respectively, were analyzed found to co-localize on the IncFrepB plasmids in isolates from pig farms' wastewater by S1-PFGE analysis. And furthermore, transmissibility of the plasmids was confirmed. Conclusions: Results obtained in this study suggested that ARGs in coliform bacteria may have been spreading on the farm via IncFrepB plasmids. Hence, appropriate use of antimicrobials and good hygiene management on the farm are required to prevent the emergence and spread of resistant bacteria. (C) 2021 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved

Lactic acid bacteria profiles associated to Thai traditional fermented foods

Probiotics are health promoting gut microbiota which has been used in commercial products to extend its benefits for supporting the gut function and immunity. Besides these, probiotics contribute to reducing blood cholesterol, diabetics, coronary heart disease, and allergic symptoms as well as improving mood along with cognitive activities, reducing skin aging, and promoting longevity. Probiotics aid in promoting longevity as a function of antioxidant activity which allows it to be a potential source of supplement. These factors open an interesting prospect of screening well known probiotics community containing higher antioxidant activity from various Thai local fermented foods. This study aimed to screen targeted lactic acid bacteria (LAB) from 15 plant and animal based Thai local fermented foods by CaCO3 containing MRS agar and analyzed its antioxidant and probiotic properties. It was found that all 11 isolates considered as potential LAB as it had shown clear zone on CaCO3 containing MRS agar, exhibited over 70% inhibition of DPPH in both supernatant and pellet. But only one isolate from plant based fermented food showed potential probiotic properties, including acid-bile tolerance, hydrophobicity, and antimicrobial activity, and it was the one that had the highest antioxidant activity. This isolated strain might be further analyzed and developed as a potential longevity promoting supplement

Use of Aeromonas spp. as General Indicators of Antimicrobial Susceptibility among Bacteria in Aquatic Environments in Thailand

Antimicrobials are widely used, not only for treating human infections, but also for treatment of livestock and in fish farms. Human habitats in Southeastern Asian countries are located in close proximity to aquatic environments. As such, the human populations within these regions are at risk of exposure to antimicrobial resistant bacteria, and thereby disseminating antimicrobial resistance genes (ARGs). In this study, we collected water samples from 15 sites (5 sites in Chao Phraya River, 2 sites at the mouth of Chao Phraya River, 3 sites in Ta Chin River, and 5 sites at city canals) and 12 sites (6 sites at city canals; 2 sites at chicken farms; 2 sites at pig farms; and 2 samples from sites at pig farms, which were subsequently treated at a biogas plant) in Thailand in 2013 and 2014, respectively. In total, 117 Aeromonas spp. were isolated from the water samples, and these organisms exhibited various antimicrobial susceptibility profiles. Notably, there was a significant correlation between the environmental concentration of tetracyclines and the rates of tetracycline resistance in the isolated Aeromonas spp.; however, both the concentration and rates of tetracycline resistance in samples derived from pig farms were higher than those of samples harvested from other aquatic environments. These findings suggest that the high concentrations of antimicrobials observed in these aquatic environments likely select for ARGs. Furthermore, they indicate that Aeromonas spp. comprise an effective marker for monitoring antimicrobial resistance in aquatic environments