6 research outputs found
Genetic diversity and population structure of Glossina pallidipes in Uganda and western Kenya
<p>Abstract</p> <p>Background</p> <p><it>Glossina pallidipes </it>has been implicated in the spread of sleeping sickness from southeastern Uganda into Kenya. Recent studies indicated resurgence of <it>G. pallidipes </it>in Lambwe Valley and southeastern Uganda after what were deemed to be effective control efforts. It is unknown whether the <it>G. pallidipes </it>belt in southeastern Uganda extends into western Kenya. We investigated the genetic diversity and population structure of <it>G. pallidipes </it>in Uganda and western Kenya.</p> <p>Results</p> <p>AMOVA indicated that differences among sampling sites explained a significant proportion of the genetic variation. Principal component analysis and Bayesian assignment of microsatellite genotypes identified three distinct clusters: western Uganda, southeastern Uganda/Lambwe Valley, and Nguruman in central-southern Kenya. Analyses of mtDNA confirmed the results of microsatellite analysis, except in western Uganda, where Kabunkanga and Murchison Falls populations exhibited haplotypes that differed despite homogeneous microsatellite signatures. To better understand possible causes of the contrast between mitochondrial and nuclear markers we tested for sex-biased dispersal. Mean pairwise relatedness was significantly higher in females than in males within populations, while mean genetic distance was lower and relatedness higher in males than females in between-population comparisons. Two populations sampled on the Kenya/Uganda border, exhibited the lowest levels of genetic diversity. Microsatellite alleles and mtDNA haplotypes in these two populations were a subset of those found in neighboring Lambwe Valley, suggesting that Lambwe was the source population for flies in southeastern Uganda. The relatively high genetic diversity of <it>G. pallidipes </it>in Lambwe Valley suggest large relict populations remained even after repeated control efforts.</p> <p>Conclusion</p> <p>Our research demonstrated that <it>G. pallidipes </it>populations in Kenya and Uganda do not form a contiguous tsetse belt. While Lambwe Valley appears to be a source population for flies colonizing southeastern Uganda, this dispersal does not extend to western Uganda. The complicated phylogeography of <it>G. pallidipes </it>warrants further efforts to distinguish the role of historical and modern gene flow and possible sex-biased dispersal in structuring populations.</p
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Hypothyroidism and Wound Healing After Salvage Laryngectomy
BACKGROUND:Patients undergoing salvage laryngectomy are predisposed to radiation-induced hypothyroidism and impaired wound healing secondary to the tissue effects of prior treatment. The impact of hypothyroidism on postoperative wound healing is not established. METHODS:A single-institution retrospective case series was performed. The inclusion criteria specified preoperatively euthyroid adults who underwent salvage laryngectomy with concurrent neck dissection between 1997 and 2015 for persistent or recurrent laryngeal squamous cell carcinoma after radiation or chemoradiation therapy (n = 182). The principal explanatory variable was postoperative hypothyroidism, defined as thyroid-stimulating hormone (TSH) higher than 5.5 mIU/L. The primary end points of the study were pharyngocutaneous fistulas and wounds requiring reoperation. Multivariate analysis was performed. RESULTS:The fistula rate was 47% among hypothyroid patients versus 23% among euthyroid patients. In the multivariate analysis, the patients who experienced hypothyroidism in the postoperative period had a 3.6-fold greater risk of fistula [95% confidence interval (CI) 1.8-7.1; p = 0.0002]. The hypothyroid patients had an 11.4-fold greater risk for a required reoperation (24.4 vs 5.4%) than the euthyroid patients (95% CI 2.6-49.9; p = 0.001). The risk for fistula (p = 0.003) and reoperation (p = 0.001) increased with increasing TSH. This corresponds to an approximate 12.5% incremental increase in the absolute risk for fistula and a 10% increase in the absolute risk for reoperation with each doubling of the TSH. CONCLUSION:Postoperative hypothyroidism independently predicts postoperative wound-healing complications. The association of hypothyroidism with fistula formation may yield opportunities to modulate wound healing with thyroid supplementation or to provide a biomarker of wound progression