De novo fragment-based design of inhibitors of DXS guided by spin-diffusion-based NMR spectroscopy

We applied for the first time an innovative ligand-based NMR methodology (STI) to a medicinal-chemistry project aimed at the development of inhibitors for the enzyme 1-deoxy-D-xylulose-5-phosphate synthase (DXS). DXS is the first enzyme of the 2C-methyl-D-erythritol-4-phosphate (MEP) pathway, present in most bacteria (and not in humans) and responsible for the synthesis of the essential isoprenoid precursors. We designed de novo a first generation of fragments, using Deinococcus radiodurans DXS as a model enzyme, targeting the thiamine diphosphate (TDP) pocket of DXS whilst also exploring the putative substrate-binding pocket, where selectivity over other human TDP-dependent enzymes could be gained. The STI methodology – suitable for weak binders – was essential to determine the binding mode in solution of one of the fragments, circumventing the requirement for an X-ray co-crystal structure, which is known to be particularly challenging for this specific enzyme and in general for weak binders. Based on this finding, we carried out fragment growing and optimisation, which led to a three-fold more potent fragment, about as potent as the well-established thiamine analogue deazathiamine. The STI methodology proved therefore its strong potential as a tool to support medicinal-chemistry projects in their early stages, especially when dealing with weak binders

Malformations ano-rectales

Anorectal malformations (ARM) are the result of an abnormal development of the terminal part of the digestive tract interesting anus and/or rectum that occur early between the sixth and tenth week of embryonic development. They carry a malformation spectrum of severity depending on the level of disruption of the anorectal canal and of the associated caudal malformations (sacrum and spine). ARM are associated in over half the cases with other malformations that can be integrated in some cases in known syndromes. If surgical treatment to restore anatomy as normal as possible is indispensable, post-operative care is essential for these patients whose defecation mechanisms are altered, to reach if not continence, at least a socially acceptable cleanliness

AluY-mediated germline deletion, duplication and somatic stem cell reversion in <i>UBE2T</i> defines a new subtype of Fanconi anemia

Fanconi anemia (FA) is a rare inherited disorder clinically characterized by congenital malformations, progressive bone marrow failure and cancer susceptibility. At the cellular level, FA is associated with hypersensitivity to DNA-crosslinking genotoxins. Eight of 17 known FA genes assemble the FA E3 ligase complex, which catalyzes monoubiquitination of FANCD2 and is essential for replicative DNA crosslink repair. Here, we identify the first FA patient with biallelic germline mutations in the ubiquitin E2 conjugase UBE2T. Both mutations were aluY-mediated: a paternal deletion and maternal duplication of exons 2-6. These loss-of-function mutations in UBE2T induced a cellular phenotype similar to biallelic defects in early FA genes with the absence of FANCD2 monoubiquitination. The maternal duplication produced a mutant mRNA that could encode a functional protein but was degraded by nonsense-mediated mRNA decay. In the patient's hematopoietic stem cells, the maternal allele with the duplication of exons 2-6 spontaneously reverted to a wild-type allele by monoallelic recombination at the duplicated aluY repeat, thereby preventing bone marrow failure. Analysis of germline DNA of 814 normal individuals and 850 breast cancer patients for deletion or duplication of UBE2T exons 2-6 identified the deletion in only two controls, suggesting aluY-mediated recombinations within the UBE2T locus are rare and not associated with an increased breast cancer risk. Finally, a loss-of-function germline mutation in UBE2T was detected in a high-risk breast cancer patient with wild-type BRCA1/2. Cumulatively, we identified UBE2T as a bona fide FA gene (FANCT) that also may be a rare cancer susceptibility gene.</p

Practical consensus guidelines for the management of enuresis

Despite the high prevalence of enuresis, the professional training of doctors in the evaluation and management of this condition is often minimal and/or inconsistent. Therefore, patient care is neither optimal nor efficient, which can have a profound impact on affected children and their families. Once comprehensive history taking and evaluation has eliminated daytime symptoms or comorbidities, monosymptomatic enuresis can be managed efficaciously in the majority of patients. Non-monosymptomatic enuresis is often a more complex condition; these patients may benefit from referral to specialty care centers. We outline two alternative strategies to determine the most appropriate course of care. The first is a basic assessment covering only the essential components of diagnostic investigation which can be carried out in one office visit. The second strategy includes several additional evaluations including completion of a voiding diary, which requires extra time during the initial consultation and two office visits before treatment or specialty referral is provided. This should yield greater success than first-line treatment. Conclusion: This guideline, endorsed by major international pediatric urology and nephrology societies, aims to equip a general pediatric practice in both primary and secondary care with simple yet comprehensive guidelines and practical tools (i.e., checklists, diary templates, and quick-reference flowcharts) for complete evaluation and successful treatment of enuresis

Developmental Transcriptional Networks Are Required to Maintain Neuronal Subtype Identity in the Mature Nervous System

During neurogenesis, transcription factors combinatorially specify neuronal fates and then differentiate subtype identities by inducing subtype-specific gene expression profiles. But how is neuronal subtype identity maintained in mature neurons? Modeling this question in two Drosophila neuronal subtypes (Tv1 and Tv4), we test whether the subtype transcription factor networks that direct differentiation during development are required persistently for long-term maintenance of subtype identity. By conditional transcription factor knockdown in adult Tv neurons after normal development, we find that most transcription factors within the Tv1/Tv4 subtype transcription networks are indeed required to maintain Tv1/Tv4 subtype-specific gene expression in adults. Thus, gene expression profiles are not simply “locked-in,” but must be actively maintained by persistent developmental transcription factor networks. We also examined the cross-regulatory relationships between all transcription factors that persisted in adult Tv1/Tv4 neurons. We show that certain critical cross-regulatory relationships that had existed between these transcription factors during development were no longer present in the mature adult neuron. This points to key differences between developmental and maintenance transcriptional regulatory networks in individual neurons. Together, our results provide novel insight showing that the maintenance of subtype identity is an active process underpinned by persistently active, combinatorially-acting, developmental transcription factors. These findings have implications for understanding the maintenance of all long-lived cell types and the functional degeneration of neurons in the aging brain

Pediatric urolithiasis: the current surgical management

Children represent about 1% of all patients with urolithiasis, but 100% of these children are considered high risk for recurrent stone formation, and it is crucial for them to receive a therapy that will render them stone free. In addition, a metabolic workup is necessary to ensure a tailored metaphylaxis to prevent or delay recurrence. The appropriate therapy depends on localization, size, and composition of the calculus, as well as on the anatomy of the urinary tract. In specialized centers, the whole range of extracorporeal shock-wave lithotripsy (ESWL), ureterorenoscopy (URS), and percutaneous nephrolithotomy (PCNL) are available for children, with the same efficiency and safety as in adults

Ultrasound screening of asymptomatic siblings of children with vesicoureteral reflux: A long-term followup study

Purpose: Siblings of patients with vesicoureteral reflux (VUR) are at greater risk of having reflux than the general population, and the role of screening in this group is widely accepted. While voiding cystourethrogram (VCUG) is the gold standard for diagnosis of VUR, ultrasound (US) is often used for screening select patients. We examine the outcomes of a conventional US screening program in older asymptomatic siblings. Materials and Methods: Between 1984 and 2003 asymptomatic siblings older than 5 years as well as children whose parents refused VCUG were screened with conventional US and urine studies. If US showed a discrepancy in renal size, renal scarring or hydronephrosis, or a change in the size of the renal pelvis during the study, then VCUG was performed. Additionally, any child with a normal US who subsequently had symptoms of urinary tract infection was then referred for VCUG. Chart review was performed and 117 siblings were identified who met these criteria (age range 2 months to 15 years). An attempt was made to contact all 117 siblings to obtain long-term followup data. Results: Of the 117 siblings 11 (9.4%) were referred for VCUG secondary to abnormal US findings (9) and development of urinary tract infection (2). VCUG was negative in the 2 symptomatic children, while 5 of the 9 (55.6%) with abnormal US were found to have VUR. Telephone contact was established with 85 of the 117 (72.6%) siblings or their parents (average followup 8.3 years, range 2 months to 19 years). All 85 siblings with available followup information had normal US, and none had had symptoms or complications of VUR since screening. Conclusions: Given the lower incidence and seemingly innocuous nature of VUR in older asymptomatic siblings of known patients with reflux, observation alone in this group is an acceptable form of management. If either parental or physician anxiety exists in this approach, then conventional US offers a reliable alternative to invasive VCUG screening in this population. Copyright © 2005 by American Urological Association

Antenatal isolated hydronephrosis associated with urinoma

Two cases of prenatally identified urinoma associated with an isolated hydronephrosis are presented, and the pathophysiology and prognosis of this rare condition are discussed. The presence in utero of a peri-renal collection associated with an isolated hydronephrosis seems to be a sign of significant renal dysplasia. These urinomas disappear spontaneously, thus drainage is not necessary, except in the case of compression of surrounding structures. The functional prognosis of these kidneys seems to be most unfavourable