Extracorporeal shock wave lithotripsy versus ureteroscopy for management of pediatric nephrolithiasis in upper urinary tract stones: multi-institutional outcomes of efficacy and morbidity.

INTRODUCTION: As the incidence of pediatric nephrolithiasis rises, understanding the efficacy and morbidity of surgical treatment options is critical. Currently, there are limited comparative data assessing shock wave lithotripsy (SWL) and ureteroscopy (URS) outcomes in children. OBJECTIVE: The objective of this study was to compare stone clearance, 30-day emergency department visits, and the number of general anesthetics required per stone treatment for both modalities. STUDY DESIGN: A multi-institutional retrospective review of children presenting for either URS or SWL between 2000 and 2017 was performed. Stone clearance, need for retreatment, the number of anesthetics, as well as the number and reason for emergency room visit were captured and compared between groups. Multivariate statistical analysis accounting for age, stone location, stone diameter, pre-intervention stent, and provider volume was performed for adjusted analysis. RESULTS: A total of 84 SWL and 175 URS procedures were included. Complete stone clearance and rates of residual stone fragments <4 mm after final procedure for SWL were 77.0% and 90.8% and for URS were 78.5% and 91.7%, respectively. Retreatment rates for both procedures were not significantly different (17.9% SWL vs. 18.9% URS, P = 0.85). Children who underwent SWL had lower rates of emergency room visits for infections (0% vs. 5.1%, P = 0.03) and flank pain (3.6% vs. 10.9%, P = 0.05) and required fewer general anesthetics per treatment (1.2 vs. 2.0, P < 0.01) than those who underwent URS (Figure). DISCUSSION: Stone clearance after both the initial and final treatments and need for repeat interventions were similar between surgical modalities. However, SWL carries less morbidity than URS. Specifically, patients who underwent SWL experienced lower rates of ED visits for urinary tract infection and for flank pain, parallel to conclusions in current comparative literature. In addition, SWL requires less general anesthetics (2.0 vs. 1.2), secondary to lower rates of ureteral stent placement and removal. Data on the potential risk of general anesthetics to neurodevelopment support thoughtful utilization of these medications. Limitations of this study include its retrospective nature and the prolonged 20-year time period over which data were collected. CONCLUSIONS: When adjusting for confounders, SWL and URS achieve similar stone clearance. In the setting of equivalent efficacy, considerations regarding necessity of repeat interventions, morbidity of anesthesia, and complications should be integrated into clinical practice.

Genetic evidence for female host-specific races of the common cuckoo.

The common cuckoo Cuculus canorus is divided into host-specific races (gentes). Females of each race lay a distinctive egg type that tends to match the host's eggs, for instance, brown and spotted for meadow pipit hosts or plain blue for redstart hosts. The puzzle is how these gentes remain distinct. Here, we provide genetic evidence that gentes are restricted to female lineages, with cross mating by males maintaining the common cuckoo genetically as one species. We show that there is differentiation between gentes in maternally inherited mitochondrial DNA, but not in microsatellite loci of nuclear DNA. This supports recent behavioural evidence that female, but not male, common cuckoos specialize on a particular host, and is consistent with the possibility that genes affecting cuckoo egg type are located on the female-specific W sex chromosome. Our results also support the ideas that common cuckoos often switched hosts during evolution, and that some gentes may have multiple, independent origins, due to colonization by separate ancestral lineages.

Egg rejection in a passerine bird: size does matter.

Avian brood parasites reduce the reproductive success of their hosts, selecting for the evolution of egg discrimination by the host, and potentially creating a coevolutionary arms race between host and parasite. Host egg discrimination ability is crucial in determining whether the arms race results in extinction (of the parasite on a particular host) or stable coevolutionary equilibrium of the host-parasite pair. I examined egg discrimination behaviour in the yellow-browed leaf warbler, Phylloscopus humei, a presumed former host of parasitic cuckoos, to show how discrimination ability has become very strong. Field experiments using model eggs demonstrate that rejection decisions are based on the relative size of eggs in the clutch. Individuals do not learn the particular size of their own eggs, but will accept both large and small eggs as long as all eggs in the clutch are of similar size. Host rejection decisions are continuously modified based on assessment of variation in egg sizes currently in the clutch, making it a difficult strategy for a cuckoo to defeat. Copyright 2000 The Association for the Study of Animal Behaviour.

Host-race formation in the common cuckoo

The exploitation of a new host by a parasite may result in host-race formation or speciation. A brood parasitic bird, the common cuckoo, is divided into host races, each characterized by egg mimicry of different host species. Microsatellite DNA markers were used to examine cuckoo mating patterns and host usage in an area where a new host has been recently colonized. Female cuckoos show strong host preferences, but individual males mate with females that lay in the nests of different hosts. Female host specialization may lead to the evolution of sex-linked traits such as egg mimicry, even though gene flow through the male line prevents completion of the speciation process.

The evolution of multiple male traits in the yellow-browed leaf warbler

I examined how male competition and female choice influence the evolution of multiple male traits in the yellow-browed leaf warbler, Phylloscopus inornatus, by investigating the roles of colour patches, territory size, body weight and song rate in sexual selection. Comparison of 3 years of observational studies and 3 years of experimental studies, in which the colour patches on the wings of males were experimentally altered, suggest several mechanisms that may explain the evolution of multiple characters in males. First, females based their choice of mates on several male characters, not a single character. Second, the male characters preferred by females were different in observational and experimental studies. Females apparently preferred high-quality males as mates, and were able to vary the characters used in mate choice to distinguish these individuals under both experimental and observational conditions. Third, the characters important in male competition differed from those that formed the basis of female choice: the manipulation of colour patch size directly affected male territory size but was not associated with female choice. These results may provide an explanation for the diversity of sexual ornaments shown by males of many species.Copyright 1998 The Association for the Study of Animal Behaviour.

A content analysis of safety behaviors of television characters: implications for children's safety and injury.

Examined frequency and characteristics of safety behaviors in television programs popular with child audiences. A sample of 52 programs was coded for safety event location, demographic characteristics of safety models, social and physical contexts of safety events, and successful or unsuccessful outcomes of safety behaviors. Results indicate an overall rate of 13 safety behaviors per hour, with hour half of all safety behaviors located in commercial advertisements. Most safety behaviors were performed by made adult characters, had limited relevance for children, and were not associated with either positive or negative outcomes. Findings are discussed in terms of their relevance for observational learning of safety behaviors by child viewers.

Costs to host defence and the persistence of parasitic cuckoos.

Raising genetically unrelated young is maladaptive, yet brood parasitism is widespread in birds. In several systems, hosts can evolve near-perfect defences against the parasite (discrimination and rejection of unlike eggs), making it difficult to understand how the parasite continues to exist. This study demonstrates costs to host defences (e.g. rejection of one's own eggs) such that once the parasite goes extinct on a particular host species, defence mechanisms are selectively disadvantageous. The consequent loss of host defences, and potential for re-exploitation of the host by the parasite, can explain the continued persistence of avian brood parasites. The results provide one general explanation for coexistence of parasites and their hosts.