1,457 research outputs found

    Feasibility of repair of distal penile hypospadias as a day-case surgery

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    Objective The aim of this study was to present the outcomes of children with distal hypospadias who were operated on outpatient basis.Methods Atotal of 47 consecutive children underwent surgical repair of distal hypospadias in our department. Urethroplasties were performed by the following techniques: stentless meatal advancement-glanuloplasty (MAGPI) or glans approximation procedure (GAP) for glanular hypospadias (14) and tubularized incised plate (TIP) urethroplasty for coronal, subcoronal and midpenil hypospadias with an indwelling urethral catheter or short stent (33). The indwelling urinary catheters were managed by the double diaper technique. Patients were discharged within 6 h after operation. Dressings and catheters were removed on the postoperative day 2 and 6, respectively.Results Voiding difficulty and urinary retention on early postoperative period were observed in 8 patients. Except meatal stenosis in 4 cases and meatal retractions in 2 cases, there were no major complications in any of our patients during the follow-up period, no postoperative fistula or urethral stricture.Conclusion In children, repair of distal penile hypospadias on outpatient basis is feasible. Catheters, urethral stents, drug therapy and dressing are not justifications for hospitalization in such cases.Keywords: hospital stay, hypospadias, outpatient, urethroplasty, wounddressin

    The value of laparoscopic classifications in decision on definitive surgery in patients with nonpalpable testes: our experience and review of the literature

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    Background/purpose The aim of the study was to present our clinical experience with the laparoscopic approach in patients with nonpalpable testes (NPTs) and review the literature on laparoscopic classifications.Materials and methods Between May 2010 and August 2012, 30 boys with NPT (mean age 3.9 years) underwent laparoscopy as a part of diagnosis and treatment in our clinic. The laparoscopic findings were classified into four types according to Castilho. The patients were managed according to the presence or position of the testes and testicular vessels.Results Six patients were excluded from the study. Twenty-six testicular units (19 left, three right, and four bilateral units) in 24 patients were managed laparoscopically. Laparoscopy was terminated in eight patients in whom blind-ending cord structures were detected intra-abdominally. An inguinal canal exploration was performed in 10 cases in whom cord structures were seen entering the internal inguinal ring. No viable testis was found, and testicular remnants were excised for histopathologic examination. Four canalicular testes (peeping) were treated with open orchiopexy. Laparoscopy-assisted orchiopexy without vascular ligation was performed in two testes. Fowler-Stephens orchiopexy in single stage was performed in one testicular unit and in two stages in another unit. All patients were discharged on the same day. The testes were normal in size and found in the scrotum after a mean follow-up period of 14 months.Conclusion The laparoscopic findings in NPT had an important influence on treatment decisions. To be able to interpret the definitive surgery relative to the laparoscopic classification, collaborative studies are required. Keywords: laparoscopy, nonpalpable testis, nubbin, orchiopexy, vas deferen

    Is legal-rational bureaucracy a prerequisite for a rational-productive bureaucracy? The case of Turkey

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    The particular pattern the bureaucratic development in Turkey has evinced suggests that legal rationality is a prerequisite for the successful institutionalization of rational productivity. Whereas there is a zero-sum type of relationship between patrimonialism on one hand and legal rationality and rational productivity on the other, there is apositive-sum type of relationship between legal rationality and rational productivity

    Identification of chromophore binding domains of yeast DNA photolyase

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    Photolyases contain two chromophores, flavin plus either methenyltetrahydrofolate (MTHF) or 8-OH-5-deazaflavin (HDF). Amino acid sequence comparison reveals that all photolyases sequenced to date have extensive sequence homology in the carboxyl-terminal half; in the amino-terminal region the folate and deazaflavin class enzymes are more homologous to other members of the same class. This modular arrangement of sequence homologies suggests that the amino-terminal half of photolyase is involved in MTHF or HDF binding whereas the carboxyl-terminal half carries the flavin binding site. In this study we attempted to identify such structural domains of yeast photolyase by partial proteolysis and gene fusion techniques. Partial digestion with chymotrypsin yielded an amino-terminal 34-kDa fragment containing tightly bound MTHF and a carboxyl-terminal 20-kDa polypeptide which lacked chromophore or DNA binding activity. However, a fusion protein carrying the carboxyl-terminal 275 amino acids of yeast photolyase bound specifically to FAD but not to MTHF or DNA. We conclude that the amino-terminal half of yeast photolyase constitutes the folate binding domain and that the carboxyl-terminal half carries the flavin binding site

    Action mechanism of Escherichia coli DNA photolyase. I. Formation of the enzyme-substrate complex.

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    Escherichia coli DNA photolyase (photoreactivating enzyme) is a flavoprotein. The enzyme binds to DNA containing pyrimidine dimers in a light-independent step and, upon illumination with 300-600 nm radiation, catalyzes the photosensitized cleavage of the cyclobutane ring thus restoring the integrity of the DNA. We have studied the binding reaction using the techniques of nitrocellulose filter binding and flash photolysis. The enzyme binds to dimer-containing DNA with an association rate constant k1 estimated by two different methods to be 1.4 X 10(6) to 4.2 X 10(6) M-1 S-1. The dissociation of the enzyme from dimer-containing DNA displays biphasic kinetics; for the rapidly dissociating class of complexes k2 = 2-3 X 10(-2) S-1, while for the more slowly dissociating class k2 = 1.3 X 10(-3) to 6 X 10(-4) S-1. The equilibrium association constant KA, as determined by the nitrocellulose filter binding assay and the flash photolysis assay, was 4.7 X 10(7) to 6 X 10(7) M-1, in reasonable agreement with the values predicted from k1 and k2. From the dependence of the association constant on ionic strength we conclude that the enzyme contacts no more than two phosphodiester bonds upon binding; this strongly suggests that the pyrimidine dimer is the main structural determinant of specific photolyase-DNA interaction and that nonspecific ionic interactions do not contribute significantly to substrate binding

    Real-time single-molecule imaging reveals a direct interaction between UvrC and UvrB on DNA tightropes

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    Nucleotide excision DNA repair is mechanistically conserved across all kingdoms of life. In prokaryotes, this multi-enzyme process requires six proteins: UvrA?D, DNA polymerase I and DNA ligase. To examine how UvrC locates the UvrB? DNA pre-incision complex at a site of damage, we have labeled UvrB and UvrC with different colored quantum dots and quantitatively observed their interactions with DNA tightropes under a variety of solution conditions using oblique angle fluorescence imaging. Alone, UvrC predominantly interacts statically with DNA at low salt. Surprisingly, however, UvrC and UvrB together in solution bind to form the previously unseen UvrBC complex on duplex DNA. This UvrBC complex is highly motile and engages in unbiased one-dimensional diffusion. To test whether UvrB makes direct contact with the DNA in the UvrBC?DNA complex, we investigated three UvrB mutants: Y96A, a b-hairpin deletion and D338N. These mutants affected the motile properties of the UvrBC complex, indicating that UvrB is in intimate contact with the DNA when bound to UvrC. Given the in vivo excess of UvrB and the abundance of UvrBC in our experiments, this newly identified complex is likely to be the predominant form of UvrC in the cell. © 2013 The Author(s)

    Blue-light-receptive cryptochrome is expressed in a sponge eye lacking neurons and opsin

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    Many larval sponges possess pigment ring eyes that apparently mediate phototactic swimming. Yet sponges are not known to possess nervous systems or opsin genes, so the unknown molecular components of sponge phototaxis must differ fundamentally from those in other animals, inspiring questions about how this sensory system functions. Here we present molecular and biochemical data on cryptochrome, a candidate gene for functional involvement in sponge pigment ring eyes. We report that Amphimedon queenslandica, a demosponge, possesses two cryptochrome/photolyase genes, Aq-Cry1 and Aq-Cry2. The mRNA of one gene (Aq-Cry2) is expressed in situ at the pigment ring eye. Additionally, we report that Aq-Cry2 lacks photolyase activity and contains a flavin-based co-factor that is responsive to wavelengths of light that also mediate larval photic behavior. These results suggest that Aq-Cry2 may act in the aneural, opsin-less phototaxic behavior of a sponge

    Transcription Factors in Light and Circadian Clock Signaling Networks Revealed by Genomewide Mapping of Direct Targets for Neurospora White Collar Complex

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    Light signaling pathways and circadian clocks are inextricably linked and have profound effects on behavior in most organisms. Here, we used chromatin immunoprecipitation (ChIP) sequencing to uncover direct targets of the Neurospora crassa circadian regulator White Collar Complex (WCC). The WCC is a blue-light receptor and the key transcription factor of the circadian oscillator. It controls a transcriptional network that regulates ∼20% of all genes, generating daily rhythms and responses to light. We found that in response to light, WCC binds to hundreds of genomic regions, including the promoters of previously identified clock- and light-regulated genes. We show that WCC directly controls the expression of 24 transcription factor genes, including the clock-controlled adv-1 gene, which controls a circadian output pathway required for daily rhythms in development. Our findings provide links between the key circadian activator and effectors in downstream regulatory pathways

    The human Rad9 checkpoint protein stimulates the carbamoyl phosphate synthetase activity of the multifunctional protein CAD

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    The human Rad9 checkpoint protein is a subunit of the heterotrimeric Rad9-Rad1-Hus1 (9-1-1) complex that plays a role as a damage sensor in the DNA damage checkpoint response. Rad9 has been found to interact with several other proteins outside the context of the 9-1-1 complex with no obvious checkpoint functions. During our studies on the 9-1-1 complex, we found that Rad9 immunoprecipitates contained a 240 kDa protein that was identified as carbamoyl phosphate synthetase/aspartate transcarbamoylase/dihydroorotase (CAD), a multienzymatic protein required for the de novo synthesis of pyrimidine nucleotides and cell growth. Further investigations revealed that only free Rad9, but not Rad9 within the 9-1-1 complex, bound to CAD. The rate-limiting step in de novo pyrimidine nucleotide synthesis is catalyzed by the carbamoyl phosphate synthetase II (CPSase) domain of CAD. We find that Rad9 binds to the CPSase domain, and, moreover, this binding results in a 2-fold stimulation of the CPSase activity of CAD. Similar results were also obtained with an N-terminal Rad9 fragment. These findings suggest that Rad9 may play a role in ribonucleotide biosynthesis

    A p53-independent role for the MDM2 antagonist Nutlin-3 in DNA damage response initiation.

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    BACKGROUND: The mammalian DNA-damage response (DDR) has evolved to protect genome stability and maximize cell survival following DNA-damage. One of the key regulators of the DDR is p53, itself tightly regulated by MDM2. Following double-strand DNA breaks (DSBs), mediators including ATM are recruited to the site of DNA-damage. Subsequent phosphorylation of p53 by ATM and ATM-induced CHK2 results in p53 stabilization, ultimately intensifying transcription of p53-responsive genes involved in DNA repair, cell-cycle checkpoint control and apoptosis. METHODS: In the current study, we investigated the stabilization and activation of p53 and associated DDR proteins in response to treatment of human colorectal cancer cells (HCT116p53+/+) with the MDM2 antagonist, Nutlin-3. RESULTS: Using immunoblotting, Nutlin-3 was observed to stabilize p53, and activate p53 target proteins. Unexpectedly, Nutlin-3 also mediated phosphorylation of p53 at key DNA-damage-specific serine residues (Ser15, 20 and 37). Furthermore, Nutlin-3 induced activation of CHK2 and ATM - proteins required for DNA-damage-dependent phosphorylation and activation of p53, and the phosphorylation of BRCA1 and H2AX - proteins known to be activated specifically in response to DNA damage. Indeed, using immunofluorescent labeling, Nutlin-3 was seen to induce formation of γH2AX foci, an early hallmark of the DDR. Moreover, Nutlin-3 induced phosphorylation of key DDR proteins, initiated cell cycle arrest and led to formation of γH2AX foci in cells lacking p53, whilst γH2AX foci were also noted in MDM2-deficient cells. CONCLUSION: To our knowledge, this is the first solid evidence showing a secondary role for Nutlin-3 as a DDR triggering agent, independent of p53 status, and unrelated to its role as an MDM2 antagonist
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