Dbx1-Expressing Cells Are Necessary for the Survival of the Mammalian Anterior Neural and Craniofacial Structures

Development of the vertebrate forebrain and craniofacial structures are intimately linked processes, the coordinated growth of these tissues being required to ensure normal head formation. In this study, we identify five small subsets of progenitors expressing the transcription factor dbx1 in the cephalic region of developing mouse embryos at E8.5. Using genetic tracing we show that dbx1-expressing cells and their progeny have a modest contribution to the forebrain and face tissues. However, their genetic ablation triggers extensive and non cell-autonomous apoptosis as well as a decrease in proliferation in surrounding tissues, resulting in the progressive loss of most of the forebrain and frontonasal structures. Targeted ablation of the different subsets reveals that the very first dbx1-expressing progenitors are critically required for the survival of anterior neural tissues, the production and/or migration of cephalic neural crest cells and, ultimately, forebrain formation. In addition, we find that the other subsets, generated at slightly later stages, each play a specific function during head development and that their coordinated activity is required for accurate craniofacial morphogenesis. Our results demonstrate that dbx1-expressing cells have a unique function during head development, notably by controlling cell survival in a non cell-autonomous manner

Parasites of non-native freshwater fishes introduced into england and wales suggest enemy release and parasite acquisition

When non-native species are introduced into a new range, their parasites can also be introduced, with these potentially spilling-over into native hosts. However, in general, evidence suggests that a high proportion of their native parasites are lost during introduction and infections by some new parasites from the native range might occur, potentially resulting in parasite spill-back to native species. These processes were investigated here using parasite surveys and literature review on seven non-native freshwater fishes introduced into England and Wales. Comparison of the mean numbers of parasite species and genera per population for each fish species England andWaleswith their native ranges revealed\9 % of the native parasite fauna were present in their populations in England and Wales. There was no evidence suggesting these introduced parasites had spilled over into sympatric native fishes. The non-native fishes did acquire parasites following their introduction, providing potential for parasite spill-back to sympatric fishes, and resulted in non-significant differences in overall mean numbers of parasites per populations between the two ranges. Through this acquisition, the non-native fishes also had mean numbers of parasite species and genera per population that were not significantly different to sympatric native fishes. Thus, the non-native fishes in England and Wales showed evidence of enemy release, acquired new parasites following introduction providing potential for spill-back, but showed no evidence of parasite spill-over

Modulation of the β-Catenin Signaling Pathway by the Dishevelled-Associated Protein Hipk1

BACKGROUND:Wnts are evolutionarily conserved ligands that signal through beta-catenin-dependent and beta-catenin-independent pathways to regulate cell fate, proliferation, polarity, and movements during vertebrate development. Dishevelled (Dsh/Dvl) is a multi-domain scaffold protein required for virtually all known Wnt signaling activities, raising interest in the identification and functions of Dsh-associated proteins. METHODOLOGY:We conducted a yeast-2-hybrid screen using an N-terminal fragment of Dsh, resulting in isolation of the Xenopus laevis ortholog of Hipk1. Interaction between the Dsh and Hipk1 proteins was confirmed by co-immunoprecipitation assays and mass spectrometry, and further experiments suggest that Hipk1 also complexes with the transcription factor Tcf3. Supporting a nuclear function during X. laevis development, Myc-tagged Hipk1 localizes primarily to the nucleus in animal cap explants, and the endogenous transcript is strongly expressed during gastrula and neurula stages. Experimental manipulations of Hipk1 levels indicate that Hipk1 can repress Wnt/beta-catenin target gene activation, as demonstrated by beta-catenin reporter assays in human embryonic kidney cells and by indicators of dorsal specification in X. laevis embryos at the late blastula stage. In addition, a subset of Wnt-responsive genes subsequently requires Hipk1 for activation in the involuting mesoderm during gastrulation. Moreover, either over-expression or knock-down of Hipk1 leads to perturbed convergent extension cell movements involved in both gastrulation and neural tube closure. CONCLUSIONS:These results suggest that Hipk1 contributes in a complex fashion to Dsh-dependent signaling activities during early vertebrate development. This includes regulating the transcription of Wnt/beta-catenin target genes in the nucleus, possibly in both repressive and activating ways under changing developmental contexts. This regulation is required to modulate gene expression and cell movements that are essential for gastrulation

Xenopus Pkdcc1 and Pkdcc2 Are Two New Tyrosine Kinases Involved in the Regulation of JNK Dependent Wnt/PCP Signaling Pathway

Protein Kinase Domain Containing, Cytoplasmic (PKDCC) is a protein kinase which has been implicated in longitudinal bone growth through regulation of chondrocytes formation. Nevertheless, the mechanism by which this occurs remains unknown. Here, we identified two new members of the PKDCC family, Pkdcc1 and Pkdcc2 from Xenopus laevis. Interestingly, our knockdown experiments revealed that these two proteins are both involved on blastopore and neural tube closure during gastrula and neurula stages, respectively. In vertebrates, tissue polarity and cell movement observed during gastrulation and neural tube closure are controlled by Wnt/Planar Cell Polarity (PCP) molecular pathway. Our results showed that Pkdcc1 and Pkdcc2 promote the recruitment of Dvl to the plasma membrane. But surprisingly, they revealed different roles in the induction of a luciferase reporter under the control of Atf2 promoter. While Pkdcc1 induces Atf2 expression, Pkdcc2 does not, and furthermore inhibits its normal induction by Wnt11 and Wnt5a. Altogether our data show, for the first time, that members of the PKDCC family are involved in the regulation of JNK dependent Wnt/PCP signaling pathway.Fundacao Ciencia e Tecnologia - IP; IBB/CBME, LA [PTDC/BIA-BCM/69912/2006, Pest-OE/EQB/LA0023/2013]; FCTinfo:eu-repo/semantics/publishedVersio

Determinants of practice patterns in pediatric UTI management

IntroductionUrinary tract infection (UTI) affects 10% of girls and 3% of boys by age 16. Both the American Academy of Pediatrics and National Institute for Health and Clinical Excellence Guidelines recommend urine testing prior to initiation of antibiotic treatment and the use of local antibiograms to guide empiric antibiotic therapy. Urine culture results not only provide the opportunity to halt empiric therapy if there is no bacterial growth, but also allow for tailoring of broad-spectrum therapy. Additionally, the use of antiobiograms improves empiric antibiotic selection based on local resistance patterns. However, execution of guideline recommendations has proved challenging. Understanding barriers in implementation is critical to developing targeted interventions aimed to improve adherence to these guidelines.ObjectivesThe present study sought to investigate practice patterns and factors that influence urine testing and antibiogram use in the setting of empiric antibiotic treatment of UTI in children to ultimately improve adherence to UTI management guidelines.Study designA random, national sample of physicians caring for children was surveyed from the American Medical Association Masterfile. Participants were queried regarding practice type, length of time in practice, factors influencing urine testing, urine specimen collection method, and antibiogram utilization. Logistic regression was used to assess factors associated with use of urine testing, bagged specimens, and antibiograms.ResultsOf respondents who acknowledged contact by surveyors, 47% completed the survey (n = 366). Most respondents (84%) obtain urinalysis and culture prior to treatment for UTI. Physicians report they would more likely order testing if the specimen were easier to collect (46%) and if results were available immediately (48%) (Table). Urine collection by bag was more common in circumcised boys (>30%) compared with girls (20%) and uncircumcised boys (20%) (P = 0.02). The most common reasons for collection by bag were parental refusal for (49%) and difficulty with (42%) catheterization (Table). Of the 70% of respondents reporting antibiogram access (n = 256), 50% report its use the majority of the time with empiric prescription (n = 128).DiscussionWhile most practitioners report following guidelines to obtain urine testing prior to antibiotic prescription for UTI, urine collection by bag is common. Additionally, <50% of practitioners adhere to guideline recommendations for empiric antibiotic selection based on local antibiograms. Interventions to improve adherence to UTI management guidelines should focus on (1) improving catheterization practices, (2) educating parents regarding the value of catheterization, and (3) incorporating local antibiograms into electronic medical records

Long-term follow-up of urethral reconstruction for blunt urethral injury at a young age: urinary and sexual quality of life outcomes.

IntroductionLittle is known about long-term patient-reported outcomes following surgical repair for pediatric blunt urethral trauma.ObjectiveThe purpose was to evaluate long-term urinary outcomes, sexual function, and quality of life (QOL) of patients who undergo urethroplasty for blunt urethral trauma in childhood.Study designAfter IRB approval, we retrospectively reviewed the records of patients who sustained blunt urethral injury at ≤18 years and underwent urethroplasty at our institution between 1978 and 2013. We then used a web-based survey to assess urinary/sexual/ejaculatory function and overall QOL using validated questionnaires.ResultsOf 68 eligible patients, 15 were able to be contacted (table). Median age of injury, age at urethroplasty, and age at follow-up were 17 (4-18), 17 (5-20), and 19 (13.5-21.5) years, respectively. The stricture was membranoprostatic in eight and bulbar in seven patients, with median length of 2 (1.6-2.6) cm. Excision/primary anastomosis was performed in all but three patients who required a buccal graft. Overall, 80% were 'very satisfied' and 20% were 'satisfied' with surgery. One patient reported a subsequent urethral intervention. On urethral stricture surgery patient-reported outcome measurement, the median bother (0 least, 24 worst) was 10 (8-12.5). The force of urine stream (1 strongest, 4 weakest) was 2 (1.5-2), with no report of urinary incontinence. The median Sexual Health Inventory for Men score (0 worst, 25 perfect) was 24 (22.5-24). The median ejaculatory function score (0 worst, 15 normal) was 14 (13-14.75). Six patients had fathered children and none reported infertility. Three patients reported <30° penile curvature not interfering with sex. Median QOL (0 worse, 10 best) was 8 (7.5-8).ConclusionsUrethroplasty after blunt urethral injury in young adult population is associated with a high long-term success rate with a low rate of long-term urinary and sexual consequences in adulthood