S ‐Aryl‐ l ‐cysteine sulphoxides and related organosulphur compounds alter oral biofilm development and AI ‐2‐based cell–cell communication

Aims To design and synthesize a library of structurally related, small molecules related to homologues of compounds produced by the plant Petiveria alliacea and determine their ability to interfere with AI ‐2 cell–cell communication and biofilm formation by oral bacteria. Many human diseases are associated with persistent bacterial biofilms. Oral biofilms (dental plaque) are problematic as they are often associated with tooth decay, periodontal disease and systemic disorders such as heart disease and diabetes. Methods and Results Using a microplate‐based approach, a bio‐inspired small molecule library was screened for anti‐biofilm activity against the oral species Streptococcus mutans UA 159 , Streptococcus sanguis 10556 and Actinomyces oris MG 1. To complement the static screen, a flow‐based BioFlux microfluidic system screen was also performed under conditions representative of the human oral cavity. Several compounds were found to display biofilm inhibitory activity in all three of the oral bacteria tested. These compounds were also shown to inhibit bioluminescence by Vibrio harveyi and were thus inferred to be quorum sensing ( QS ) inhibitors. Conclusion Due to the structural similarity of these compounds to each other, and to key molecules in AI ‐2 biosynthetic pathways, we propose that these molecules potentially reduce biofilm formation via antagonism of QS or QS ‐related pathways. Significance and Impact of the Study This study highlights the potential for a non‐antimicrobial‐based strategy, focused on AI ‐2 cell–cell signalling, to control the development of dental plaque. Considering that many bacterial species use AI ‐2 cell–cell signalling, as well as the increased concern of the use of antimicrobials in healthcare products, such an anti‐biofilm approach could also be used to control biofilms in environments beyond the human oral cavity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109321/1/jam12616.pd

Evaluation of plasma osmolality using direct method and its measurement in infants under fluid therapy

History and Objectives: Considering the significance of plasma osmolality as an appropriate indicator of water and electrolyte balance, its importance as a stimulus and the extent of its difference with real osmolality, this study was carried out to determine plasma osmolality and its measurement in infants under fluid therapy in selected hospitals in Isfahan.Materials and Methods: The cross-sectional protocol of this study was carried out on 45 infants at an age of 1-10 days in wards of special care for infants. Plasma osmolality was measured using direct method and also through measuring sodium, potassium, glucose and BUN concentrations. Then, paired t-test was applied regarding weight and degree of attention.Results: The measured osmolality was 260.57±1.84 mosmol/kg and was significantly different from the predicted one. These findings were also correct for infants with weights higher than 2500g. Conclusion and Recommendations: The above-mentioned method can correctly measure plasma osmolality as direct method. It is concluded to use in order of importance direct method and then mathematical method for measurement of plasma osmolality