Impact of a more restrictive approach to urinary tract imaging after febrile urinary tract infection.

OBJECTIVES: To determine the impact of using an algorithm requiring selective rather than routine urinary tract imaging following a first febrile urinary tract infection (UTI) on imaging use, detection of vesicoureteral reflux (VUR), prophylactic antibiotic use, and UTI recurrence within 6 months. DESIGN: Retrospective review comparing outcomes during periods before algorithm use (September 1, 2006, to August 31, 2007) and after algorithm use (September 1, 2008, to August 31, 2009). The new algorithm, which adapted recommendations from the United Kingdom's National Institute for Health and Clinical Excellence 2007 guidelines, was implemented in 2008. The algorithm calls for renal ultrasonography in most cases and restricts voiding cystourethrography for use in patients with certain risk factors. SETTING: County health system. PARTICIPANTS: Children younger than 2 years with a first febrile UTI. INTERVENTION: Selective algorithm for urinary tract imaging. MAIN OUTCOME MEASURES: Urinary tract imaging use, detection of VUR, prophylactic antibiotic use, and UTI recurrence within 6 months. RESULTS: After introduction of the new algorithm, voiding cystourethrography and prophylactic antibiotic use decreased markedly. Rates of UTI recurrence within 6 months and detection of grades 4 and 5 VUR did not change, but detection of grades 1 to 3 VUR decreased substantially. Patients in the prealgorithm group with grades 1 to 3 VUR who would have been missed with selective screening underwent no interventions other than successive urinary tract imaging and prophylactic antibiotic use. CONCLUSIONS: By restricting urinary tract imaging after an initial febrile UTI, rates of voiding cystourethrography and prophylactic antibiotic use decreased substantially without increasing the risk of UTI recurrence within 6 months and without an apparent decrease in detection of high-grade VUR. Clinicians can be more judicious in their use of urinary tract imaging.

Sex differences in the cannabinoid modulation of an A-type K+ current in neurons of the mammalian hypothalamus.

Cannabinoids regulate biological processes governed by the hypothalamus including, but not limited to, energy homeostasis and reproduction. The present study sought to determine whether cannabinoids modulate A-type K(+) currents (I(A)) in neurons of the hypothalamic arcuate nucleus (ARC). Whole cell patch-clamp recordings were performed in slices through the ARC prepared from castrated female and male guinea pigs. Forty percent of guinea pig ARC neurons exhibited a transient outward current that was antagonized by high (mM) concentrations of 4-aminopyridine and (100 nM) rHeteropodatoxin-2. Five of these neurons also were immunopositive for both beta-endorphin and the Kv4.2 channel subunit. Bath application of the CB1 receptor agonists WIN 55,212-2 (1 microM) or ACEA (1 microM) selectively induced a rightward shift in the inactivation curve for the I(A), significantly increasing the half-maximal voltage without affecting the peak current magnitude, in neurons from female but not male animals. The CB1 receptor antagonist AM251 (1 microM) reversed this action. Collectively, these data reveal that guinea pig ARC neurons, including proopiomelanocortin neurons, express a prominent I(A) that is positively modulated by cannabinoids in a sex-specific way by altering the voltage dependence of its inactivation. The resultant inhibitory effect on this neuronal population may shed some insight into the mechanism(s) by which cannabinoids influence hypothalamic function.