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BackgroundSocial networking sites (SNSs) such as Facebook have the potential to enhance online public health interventions, in part, as they provide social exposure and reinforcement. ObjectiveThe objective of the study was to evaluate whether social exposure provided by SNSs enhances the effects of online public health interventions. MethodsAs a sample intervention, we developed Food Hero, an online platform for nutritional education in which players feed a virtual character according to their own nutritional needs and complete a set of virtual sport challenges. The platform was developed in 2 versions: a "private version" in which a user can see only his or her own score, and a "social version" in which a user can see other players’ scores, including preexisting Facebook friends. We assessed changes in participants’ nutritional knowledge using 4 quiz scores and 3 menu-assembly scores. Monitoring feeding and exercising attempts assessed engagement with the platform. ResultsThe 2 versions of the platform were randomly assigned between a study group (30 members receiving the social version) and a control group (33 members, private version). The study group's performance on the quizzes gradually increased over time, relative to that of the control group, becoming significantly higher by the fourth quiz (P=.02). Furthermore, the study group's menu-assembly scores improved over time compared to the first score, whereas the control group's performance deteriorated. Study group members spent an average of 3:40 minutes assembling each menu compared to 2:50 minutes in the control group, and performed an average of 1.58 daily sport challenges, compared to 1.21 in the control group (P=.03). ConclusionsThis work focused on isolating the SNSs' social effects in order to help guide future online interventions. Our results indicate that the social exposure provided by SNSs is associated with increased engagement and learning in an online nutritional educational platform.

Research on renal medullary hypoxia has shed light on ways to protect patients from kidney damage. The renal medulla is the part of the kidney that concentrates urine to conserve body water. However, this reduces the oxygen content of the medulla, a condition called hypoxia. The body has many ways of minimizing the damage to the medulla. The medulla has receptors for many chemicals that relax blood vessels in the kidney, which increases oxygen content. However, many drugs can increase medullary hypoxia by reducing blood flow or increasing the transport of ions in the kidney tubules. These drugs include some antibiotics, non-steroidal anti-inflammatory drugs and contrast dyes used in imaging procedures. Medullary hypoxia can not be detected, but it can be minimized by infusing a salt solution into hospitalized patients who are receiving these chemicals.

A study of renal cortical and medullary oxygen tensions (PO2) by introducing sensitive Clark-type O2 microelectrodes using micromanipulators in anaesthetized rat kidney cortex and medulla reveals that cortical PO2 is higher than medullary PO2 under basal conditions. Furosemide, a medullary thick ascending limb resorptive transport inhibitor, enhances medullar PO2, without affecting cortical PO2. This effect, resulting from reduced tubular O2 consumption, is specific for loop diuretics. Acetazolamide, a proximal tubule metabolism inhibitor, specifically enhances cortical PO2.