Systematic review of the limited evidence base for treatments of Eustachian tube dysfunction: a health technology assessment.

BACKGROUND: The Health Technology Assessment programme commissioned a wide-ranging review of treatments for adult Eustachian tube dysfunction. Treatments range from advice and observation and pharmacological treatments to surgical options. OBJECTIVE: (i) To assess the evidence for interventions for adults with a clinical diagnosis of Eustachian tube dysfunction and (ii) to identify priorities for future research. TYPE OF REVIEW: Systematic review (PROSPERO registration CRD42012003035) adhering to PRISMA guidance. SEARCH: An extensive search of 15 databases including MEDLINE, EMBASE and CENTRAL (up to October 2012). EVALUATION METHOD: Controlled and uncontrolled studies of interventions for adult Eustachian tube dysfunction were included. Because of insufficient data, the protocol was amended to also include controlled studies with mixed adult/child populations. Risk of bias was assessed. Narrative synthesis was employed due to high clinical heterogeneity. RESULTS: Interventions assessed were pharmacological treatments [two randomised controlled trials (RCTs), one controlled non-randomised trial (CCT), 159 patients]; mechanical pressure equalisation devices (one randomised controlled trial, one CCT, 48 patients); and surgery, including laser tuboplasty (seven case series, 192 patients), balloon dilatation (three case series, 103 patients), myringotomy without grommet insertion (two case series, 121 patients), transtubal steroids (one case series, 11 patients) and laser coagulation (one retrospective controlled study, 40 patients). All studies had high risk of bias except two pharmacological trials; one had low risk and one unclear risk. No evidence was found for many treatments. The single low risk of bias RCT (n = 91; 67% adults) showed no effect of nasal steroids and favoured placebo for improved middle ear function (RR 1.20, 95% CI 0.91-1.58) and symptoms (P = 0.07). Other studies showed improvements in middle ear function for mechanical devices, antihistamine/ephedrine and nasal decongestant, but they had significant methodological weaknesses including insufficient length of follow-up. None of the surgical studies were adequately controlled, and many reported high levels of co-intervention. Therefore, observed benefits for tuboplasty and balloon dilatation in symptoms, middle ear function or hearing could not be reliably attributed to the interventions assessed. There was variability in definitions of the condition. CONCLUSION: Eustachian tube dysfunction is a poorly defined condition. Due to the limited and poor-quality evidence, it is inappropriate to make conclusions on the effectiveness of any intervention; the evidence base is insufficient to guide recommendations for a trial of any particular intervention. Consensus on diagnostic criteria for Eustachian tube dysfunction is required to inform inclusion criteria of future trials.

RAPD marker estimation of genetic structure among isolated northern leopard frog populations in the south-western USA.

Amphibians in the south-western United States are currently experiencing population declines. Causal explanations for these population changes as well as the implementation of sound management practices requires an understanding of the genetic structure of natural amphibian populations. To this end, we estimated genetic differences within and among seven isolated populations of northern leopard frogs, Rana pipiens, from Arizona and southern Utah using random amplified polymorphic DNA (RAPD) analyses. Fourteen arbitrarily designed primers detected 38 polymorphic loci in 85 individual frogs. Three types of population structure were observed in this study. (i) Two populations showed low genetic diversity (D = 0.10 and 0.04) and may have been established by relatively recent events. (ii) Two were not genetically distinct and exhibited a high degree of within-population diversity (D = 0.35). The possibility of gene flow between these populations is high due to their geographical proximity and their shared genetic structure. (iii) Three populations were genetically distinct from each other and the other populations, and exhibited intermediate within-population variation (D = 0.19, 0.17, 0.14). Genetic distances among the seven populations ranged from 0.00 to 0.20, suggesting that some of these leopard frog populations are genetically distinct. Although based on relatively small samples, these data suggest that leopard frog populations in the south-west are likely to represent unique genetic entities worthy of conservation. The management implications of these results are that isolated leopard frog populations should be evaluated on an individual basis to best preserve them.

Variability in grape phylloxera preference and performance on canyon grape (Vitis arizonica).

We tested the deme-formation hypothesis experimentally with four populations of leaf-galling grape phylloxera, Daktulosphaira vitifoliae, and its host, canyon grape (Vitis arizonica). An experiment designed to examine preference and performance showed that phylloxera populations did not significantly prefer their original host relative to other hosts in the percent available leaves galled. There were significant herbivore population effects (P<0.01), host effects (P<0.001), and population x host interaction effects (P<0.001). Herbivore populations had different colonizing abilities (performance, as measured in the mean number of galls per leaf) on an individual host (P<0.001), but there was no host effect. Host genotype significantly affected phylloxera performance, measured as survivorship (P<0.01), but a phylloxera population did not necessarily have higher survivorship on its original host. Differences in fecundity, an-other measurement of performance, were due to intrinsic differences among herbivore populations (P<0.05), and not related to host genotype. There was no correlation between distance from a phylloxera population in the field and a host's susceptibility to attack. There was a significant positive relationship between levels of infestation on a clone in the field and its susceptibility to colonization experimentally (P<0.05), suggesting inherent differences in host resistance and susceptibility. These results did not support the deme-formation hypothesis. In a second experiment, host clone x water treatment interactions affected phylloxera survivorship (P<0.05) and fecundity (P<0.05). We conclude that host genotype x environment interactions may prevent sessile, parthenogenetic herbivores from locally adapting to individual host genotypes.