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Glial-cell-line-derived neurotrophic factor (GDNF) belongs to the TGF-[Beta] super-family. It signals through Ret receptor tyrosine kinase and employs GDNF family receptor [Alpha]-1 (GFR[Alpha]-1) as a co-receptor. Gene targeted mice lacking GDNF or its receptors show severe defects in the enteric innervation, and they lack kidneys or show renal hypodysplasia. In nephrogenesis, GDNF and its receptors are required for the ureteric bud outgrowth and subsequent branching. GDNF-soaked agarose beads placed next to the Wolffian duct of E11 mouse embryo urogenitals induce ectopic budding from any segment of Wolffian duct. We have now studied the molecular characteristics of the GDNF-induced ectopic buds. Normally, when the ureteric bud is forming, the Ret expression is rapidly downregulated in the Wolffian duct and becomes restricted to the area of the presumptive ureteric bud. Later, Ret is expressed only by the tip of the bud. Whole mount in situ hybridization of the GDNF-bead-treated explants showed upregulation of the GDNF receptors by the ectopic buds. Moreover, Pax2 was expressed in this newly formed epithelia suggesting that the ectopic ureteric buds might be competent to induce nephrogenesis, if nephrogenic mesenchyme is transplanted to these sites.

We studied the relationship between heterozygosity and infection by trematode parasites in eight populations of Lymnaea stagnalis. Within natural populations, prevalences of trematode infection were high, from 37% to 94%, and there was no relationship between infection status and individual heterozygosity at microsatellite loci. Additionally, among populations, parasite prevalence was not correlated with population genetic diversity or population selfing rate. We further studied the relationship between heterozygosity and parasite infection in a controlled experimental set-up, in which self- and cross-fertilized snails were exposed to an allopatric population of parasites in seminatural conditions. In the experiment, selfed offspring were no more susceptible to trematode infection than outcrossed offspring, a result in line with observations from the natural populations. However, population genetic diversity was a significant factor determining infection probability; snails from less heterozygous populations were more likely to be infected than snails from more heterozygous populations. The lack of a relationship between parasite infection and heterozygosity in natural populations can be explained by the probable high spatial and temporal variation in parasite exposure both within and among populations. Local genetic adaptation of parasites to their snail intermediate hosts may be hampered by high gene flow in the parasite populations.

Background: Studies assaying morbidity related to sinonasal inverted papilloma (SNIP) and its treatment are lacking. We evaluated how operative treatment of SNIP affects patients' health-related quality of life (HRQoL) and symptoms., Methods: We prospectively recruited consecutive patients (n=52) operated for SNIP at Helsinki University Hospital, between years 2016 and 2019. In total, 42 patients filled in the 15D, a generic HRQoL instrument and a symptom questionnaire preoperatively and at 1 year and at 2 years postoperatively. The 15D HRQoL scores were compared to those of age- and sex-standardized general population., Results: Patients' mean baseline score for discomfort and symptoms (one of the 15D dimensions) was significantly better compared to general population, but this difference faded postoperatively. Frequency of epistaxis, nasal obstruction, lowered sense of smell, headache, tinnitus and epiphora decreased significantly during follow-up whereas frequency of numbness of the face or mouth increased. Difference in the mean 15D score of the patients compared with general population was insignificant at baseline and at 1 year and at 2 years postoperatively., Conclusions: Measured by a generic HRQoL questionnaire, the mean score for discomfort and symptoms deteriorated after operative treatment of SNIP. Despite a relief of many symptoms, care should be taken when operating a benign tumour, as surgery may cause morbidity.