Deletion of neurturin impairs development of cholinergic nerves and heart rate control in postnatal mouse hearts.

The neurotrophic factor neurturin is required for normal cholinergic innervation of adult mouse heart and bradycardic responses to vagal stimulation. Our goals were to determine effects of neurturin deletion on development of cardiac chronotropic and dromotropic functions, vagal baroreflex response, and cholinergic nerve density in nodal regions of postnatal mice. Experiments were performed on postnatal C57BL/6 wild-type (WT) and neurturin knockout (KO) mice. Serial electrocardiograms were recorded noninvasively from conscious pups using an ECGenie apparatus. Mice were treated with atenolol to evaluate and block sympathetic effects on heart rate (HR) and phenylephrine (PE) to stimulate the baroreflex. Immunohistochemistry was used to label cholinergic nerves in paraffin sections. WT and KO mice showed similar age-dependent increases in HR and decreases in PR interval between postnatal days (P) 2.5 and 21. Treatment with atenolol reduced HR significantly in WT and KO pups at P7.5. PE caused a reflex bradycardia that was significantly smaller in KO pups. Cholinergic nerve density was significantly less in nodal regions of P7.5 KO mice. We conclude that cholinergic nerves have minimal influence on developmental changes in HR and PR, QRS, and QTc intervals in mouse pups. However, cholinergic nerves mediate reflex bradycardia by 1 week postnatally. Deletion of neurturin impairs cholinergic innervation of the heart and the vagal efferent component of the baroreflex early during postnatal development.

Poor hand hygiene by college students linked to more occurrences of infectious diseases, medical visits, and absence from classes.

BACKGROUND: Proper hand hygiene has been linked to lower susceptibility to infectious diseases in many types of communities, but it has not been well established on college campuses. This study investigated the hand hygiene statuses of college students and their occurrences in relation to infectious diseases, medical visits, and absence from classes or work. It also examined the effects of education on handwashing technique to improve hand hygiene. METHODS: College students enrolled at a university in Northwestern Ohio were recruited as study subjects. Microbial samples were collected 3 times from each of the 220 valid volunteers before washing their hands, after washing with their own procedures, and after washing with a procedure recommended by the Centers for Disease Control and Prevention (CDC). Each volunteer also answered a survey including questions on their health conditions, medical visits, and absence from classes or work. RESULTS: Hands of 57.7% volunteers were colonized by an uncountable number of microbial colonies, which were significantly linked to more occurrences to infectious diseases (P < .05), medical visits (P < .05), and arguably more absence from classes or work (P = .09). The handwashing procedure provided by the CDC significantly improved hand hygiene. CONCLUSION: It is critical to promote education on proper handwashing in colleges, in grade schools, and at home to improve health and learning outcomes.