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At least 847 records · Page 47Linked to original sources
PubMed1998

Urethral duplication in children: surgical treatment and results.

PURPOSE: Urethral duplication is a rare congenital anomaly. We report the clinical presentation, imaging findings and surgical treatment in 7 boys with incomplete sagittal duplication of the urethra. MATERIALS AND METHODS: Duplication involved hypospadias in 5 cases (group 1) and a bifid urethra with an accessory preanal tract (Y duplication) in 2 (group 2). Group 1 was treated with 1-stage urethroplasty, including marsupialization of the dorsal orthotopic urethra, ventral-to-dorsal urethrourethrostomy and penile island flap onlay repair to cover the open dorsal urethra. In contrast, group 2 was treated with 2-stage urethral reconstruction with detachment and mobilization of the accessory preanal branch in association with a scrotal tubed neourethra followed by urethroplasty, as in group 1. In all cases the dorsal penile urethra was located between the corpora cavernosa and surrounded by the tunica albuginea. RESULTS: A urethrocutaneous fistula developed in 1 of the 5 group 1 patients. In group 2, 1 patient had recurrent penoscrotal meatal stenosis after the 1-stage procedure and 1 had a urethral diverticulum with calculi at the scrotal tubed neourethra 7 years after urethral reconstruction. Six of the 7 patients now void spontaneously through a meatus located normally at the tip of the glans. The remaining patient with a neurogenic bladder is on intermittent catheterization via appendicovesicostomy due to difficult catheterization of the irregular and sensitive neourethra. CONCLUSIONS: While the ideal surgical management of urethral duplication anomalies remains uncertain, we used a combination of surgical techniques to correct this severe malformation.

Child↗
PubMed1991

Nonsurgical management of primary vesicoureteral reflux in complete ureteral duplication: is it justified?

We reviewed the treatment of 56 children with vesicoureteral reflux and complete duplication of the collecting system, including 14 who had complete bilateral duplication. A total of 70 refluxing duplicated systems was analyzed. Of the patients 18% demonstrated spontaneous resolution of reflux within 42 months, 23% are currently stable on prophylactic antibiotics and 57.1% underwent surgical correction. Spontaneous resolution of reflux occurred in 58% of the children with grades I to III/V reflux. In comparing the group with reflux and duplication to a group with reflux into single systems, we conclude that the patients with duplication and lower grades of reflux can be managed nonoperatively, while infection is prevented with antibiotic prophylaxis.

Child, Preschool↗
PubMed1995

Colonic duplication: an unusual cause of enterovesical fistula.

Intestinal duplications are rare, occurring in 1 in 4000 births. Even rarer are tubular hindgut duplications, with less than 75 cases reported in the literature to date. We report an uncommon case of an enterovesical fistula caused by a duplication of the sigmoid colon. This is the first reported case of a tubular colonic duplication presenting as a colovesical fistula in an adult. We discuss the presentation and shortcomings in the diagnosis and treatment of enterovesical fistulas and colonic duplications.

Adult↗
PubMed2000

Nucleophosmin/B23 is a target of CDK2/cyclin E in centrosome duplication.

In animal cells, duplication of centrosomes and DNA is coordinated. Since CDK2/cyclin E triggers initiation of both events, activation of CDK2/cyclin E is thought to link these two events. We identified nucleophosmin (NPM/B23) as a substrate of CDK2/cyclin E in centrosome duplication. NPM/B23 associates specifically with unduplicated centrosomes, and NPM/B23 dissociates from centrosomes by CDK2/cyclin E-mediated phosphorylation. An anti-NPM/B23 antibody, which blocks this phosphorylation, suppresses the initiation of centrosome duplication in vivo. Moreover, expression of a nonphosphorylatable mutant NPM/ B23 in cells effectively blocks centrosome duplication. Thus, NPM/B23 is a target of CDK2/cyclin E in the initiation of centrosome duplication.

3T3 Cells↗
PubMed1999

Physical mapping of a tandem duplication on the long arm of chromosome 7 associated with a multidrug resistant phenotype.

Both the expression of the multidrug transporter, P-glycoprotein (Pgp), and abnormalities of the long arm of chromosome 7 have been shown to be adverse prognostic indicators in acute leukemias. In this study, a clonal duplication, dup(7)(q11.1q31.1), inherited with the classical multidrug resistant phenotype in a drug-resistant derivative of a human T-cell leukemia cell line was characterized. The position of the duplication was of interest as the gene which encodes Pgp, MDR1, is located on the long arm of chromosome 7 at position 7q21.1. Fluorescence in situ hybridization (FISH) analysis with a chromosome 7-specific painting probe confirmed the composition of the abnormal chromosome. A YAC clone hybridizing to the MDR1 locus confirmed that this gene was located within the duplicated region of the derivative chromosome. With a panel of well-characterized YAC clones, the duplicated segment was found to be a direct tandem duplication, somewhat larger than estimated by conventional cytogenetics. The proximal and distal breakpoints of the abnormality were located and a YAC clone spanning the distal breakpoint was identified. This clone is of particular interest, as it harbors the markers D7S523 and D7S471, close to which a putative tumor suppressor gene is thought to lie. Further examination of the breakpoint region may therefore illuminate the mechanism of Pgp upregulation as well as providing information about a tumor suppressor gene.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Diprosopus (partially duplicated head) associated with anencephaly: a case report.

Craniofacial duplication (diprosopus) is a rare form of conjoined twin. A 16 year old mother with a twin pregnancy delivered one normally formed baby boy and one diprosopus male. The malformed baby was 33 weeks of gestation with a single trunk, normal limbs and various degrees of facial duplication. Of the following structures there were two of each: noses, eyes, ears (and one dimple), mouths, tongues and, with bilateral central cleft lips and cleft palates. This was associated with holoprosencephaly and craniorachischisis. Internal organs showed no duplication. There were multiple congenital anomalies including diaphragmatic hernia, small lungs, two lobes of the right lung, ventricular septal defect, small adrenal gland and small left kidney with short ureter. The body also had a short neck, small chest cavities and kyphosis. X-ray revealed duplication of the vertebral column. The case presented here represents a type II of diprosopia of Rating (1933) and is the least common type reported. We also reviewed 22 recently reported cases of diprosopus. In addition to facial duplication, anencephaly, neural tube defect and cardiac malformations represent the more common congenital abnormalities associated with diprosopus. The pathogenesis of diprosopus is not well understood. Factors that play a role in diprosopus are probably similar to those factors (genetic, environmental and abnormal placental circulation) which affect monozoygotic twins as observed in this case report. Early ultrasonography diagnosis of diprosopus permits one to consider a vaginal therapeutic abortion.

Abnormalities, Multiple↗
PubMed2000

The SCF ubiquitin ligase protein slimb regulates centrosome duplication in Drosophila.

The duplication of the centrosome is a key event in the cell-division cycle. Although defects in centrosome duplication are thought to contribute to genomic instability [1-3] and are a hallmark of certain transformed cells and human cancer [4-6], the mechanism responsible for centrosome duplication is not understood. Recent experiments have established that centrosome duplication requires the activity of cyclin-dependent kinase 2 (Cdk2) and cyclins E and A [7-9]. The stability of cyclin E is regulated by the ubiquitin ligase SCF, which is a protein complex composed of Skp1, Cdc53 (Cullin) and F-box proteins [10-12]. The Skp1 and Cullin components have been detected on mammalian centrosomes, and shown to be essential for centrosome duplication and separation in Xenopus [13]. Here, we report that Slimb, an F-box protein that targets proteins to the SCFcomplex [14,15], plays a role in limiting centrosome replication. We found that, in the fruit fly Drosophila, the hypomorphic mutation slimb(crd) causes the appearance of additional centrosomes and mitotic defects in mutant larval neuroblasts.

Animals↗
PubMed2001

Skin prick test in duplicate: is it necessary?

BACKGROUND: Duplicate skin prick testing has previously been recommended because of reports that accidental negative tests are common. However, duplicate tests also mean an extra allergen load, which may increase the risk of inducing a generalized reaction at the test situation, at least in the youngest infants. OBJECTIVE: To investigate whether the occurrence of both a positive and negative test result is a common feature when performing duplicate skin prick tests and can therefore justify the duplicate method. METHODS: A retrospective analysis of all skin prick tests performed in duplicate at the pediatric clinic at University Hospital in Linköping, Sweden, in 1997. RESULTS: Of 1,087 skin prick tests, 14 resulted in one positive and one negative test, or 1.3%. The corresponding figure in the youngest age group, (ie, <2 years of age) was 3 of 340 (0.9%). CONCLUSIONS: Considering the risk of inducing a summation of the reactions, and thereby a generalized allergic reaction, when applying an extra allergen load on the limited surface of the small arm, we conclude that the results of this study justify using single prick test, at least in the youngest age group and probably when testing children of all ages.

Adolescent↗
PubMed1998

Tandem duplication of nucleolus organizer region (NOR) in the Japanese macaque, Macaca fuscata fuscata.

During exploration of chromosome polymorphisms in Japanese macaques, a heteromorphic polymorphism was found in a population in the Zigokudani monkey park. The population consisted of three troops (social units). Of 36 monkeys examined, five females showed heterozygotic 'marker' chromosome (chromosome 9). The polymorphism was a tandem duplication of the nucleolus organizer region (NOR) of the short arm of chromosome 9, which was found for the first time in the genus Macaca. FISH and fibre-FISH using human 18S rDNA and sequential silver nitrate staining revealed that the duplicated region included a part of the euchromatic satellite and the stalk and that the euchromatic block (intercalary satellite) divided the NOR into two parts (distal and proximal). Furthermore, it showed that the distal region possessed much more rDNA than the proximal region, and that the duplications might have been introduced via a mechanism of gene amplification (inverted duplications associated with over-replication and recombination events). As the tandem duplication was observed sporadically in four maternal pedigrees in two troops and the mothers of the variants all had normal chromosomes, the variation might have been introduced from another population's gene pool by a solitary male immigrant.

Animals↗
PubMed2004

Bi-directional duplex promoters with duplicated enhancers significantly increase transgene expression in grape and tobacco.

Novel bi-directional duplex promoters (BDDP) were constructed by placing two identical core promoters divergently on both upstream and downstream sides of their duplicated enhancer elements. Estimates of promoter function were obtained by creating versions of CaMV 35S and CsVMV BDDPs that contained reporter marker genes encoding beta-glucuronidase (GUS) and enhanced green fluorescent protein (EGFP) interchangeably linked either to the upstream or downstream core promoters. GUS was used for quantitative analysis of promoter function, whereas, EGFP allowed visual qualitative evaluation. In addition, the GUS and EGFP genes placed in downstream positions were modified by translational fusion with neomycin phosphotransferase (NPTII) to allow simultaneous monitoring of promoter activity and selection of stable transformants. These versions of BDDP were compared with each other and with equivalent unidirectional constructs by evaluating their expression in grape and tobacco. For 35S promoter constructs tested in grape somatic embryos (SE), BDDP exhibited transient GUS expression 206- and 300-fold greater in downstream and upstream configurations, respectively, compared to a unidirectional 35S core promoter. Compared with a unidirectional double enhanced 35S promoter, BDDPs exhibited 0.5- and 3-fold increased GUS expression from downstream and upstream core promoters, respectively. The same differences in expression levels determined quantitatively with GUS were distinguished qualitatively with EGFP. Constructs using CsVMV core promoters yielded results relative to those obtained with 35S promoter. For example, the upstream BDDP CsVMV core promoter provided a 200-fold increase in GUS expression compared to a unidirectional core promoter. However, CsVMV promoter was found to have higher promoter activity than 35S promoter in both BDDP and unidirectional constructs. Incorporation of an additional duplicated enhancer element to BDDPs resulted in increased expression. For example, a 35S BDDP with two divergently arranged duplicated enhancer elements resulted in over a 6-fold increase in GUS expression in stably transformed tobacco plants compared to a BDDP with one duplicated enhancer element. Data demonstrate that BDDP composed of divergently-arranged core promoters separated by duplicated enhancers, all derived from a single promoter sequence, can be used to significantly enhance transgene expression and to direct synchronized expression of multiple transgenes.

Amino Acid Oxidoreductases↗
PubMed1999

Centrosome duplication in mammalian somatic cells requires E2F and Cdk2-cyclin A.

Centrosome duplication is a key requirement for bipolar spindle formation and correct segregation of chromosomes during cell division. In a manner highly reminiscent of DNA replication, the centrosome must be duplicated once, and only once, in each cell cycle. How centrosome duplication is regulated and coordinated with other cell-cycle functions remains poorly understood. Here, we have established a centrosome duplication assay using mammalian somatic cells. We show that centrosome duplication requires the activation of E2F transcription factors and Cdk2-cyclin A activity.

Animals↗
PubMed2000

Molecular mechanism for duplication 17p11.2- the homologous recombination reciprocal of the Smith-Magenis microdeletion.

Recombination between repeated sequences at various loci of the human genome are known to give rise to DNA rearrangements associated with many genetic disorders. Perhaps the most extensively characterized genomic region prone to rearrangement is 17p12, which is associated with the peripheral neuropathies, hereditary neuropathy with liability to pressure palsies (HNPP) and Charcot-Marie-Tooth disease type 1A (CMT1A;ref. 2). Homologous recombination between 24-kb flanking repeats, termed CMT1A-REPs, results in a 1.5-Mb deletion that is associated with HNPP, and the reciprocal duplication product is associated with CMT1A (ref. 2). Smith-Magenis syndrome (SMS) is a multiple congenital anomalies, mental retardation syndrome associated with a chromosome 17 microdeletion, del(17)(p11.2p11.2) (ref. 3,4). Most patients (>90%) carry deletions of the same genetic markers and define a common deletion. We report seven unrelated patients with de novo duplications of the same region deleted in SMS. A unique junction fragment, of the same apparent size, was identified in each patient by pulsed field gel electrophoresis (PFGE). Further molecular analyses suggest that the de novo17p11.2 duplication is preferentially paternal in origin, arises from unequal crossing over due to homologous recombination between flanking repeat gene clusters and probably represents the reciprocal recombination product of the SMS deletion. The clinical phenotype resulting from duplication [dup(17)(p11.2p11.2)] is milder than that associated with deficiency of this genomic region. This mechanism of reciprocal deletion and duplication via homologous recombination may not only pertain to the 17p11.2 region, but may also be common to other regions of the genome where interstitial microdeletion syndromes have been defined.

Abnormalities, Multiple↗
PubMed2005

Temporal and spatial control of nucleophosmin by the Ran-Crm1 complex in centrosome duplication.

Centrosome duplication is tightly controlled during faithful cell division, and unnecessary reduplication can lead to supernumerary centrosomes and multipolar spindles that are associated with most human cancer cells. In addition to nucleocytoplasmic transport, the Ran-Crm1 network is involved in regulating centrosome duplication to ensure the formation of a bipolar spindle. Here, we discover that nucleophosmin (NPM) may be a Ran-Crm1 substrate that controls centrosome duplication. NPM contains a functional nuclear export signal (NES) that is responsible for both its nucleocytoplasmic shuttling and its association with centrosomes, which are Ran-Crm1-dependent as they are sensitive to Crm1-specific nuclear export inhibition, either by leptomycin B (LMB) or by the expression of a Ran-binding protein, RanBP1. Notably, LMB treatment induces premature centrosome duplication in quiescent cells, which coincides with NPM dissociation from centrosomes. Moreover, deficiency of NPM by RNA interference results in supernumerary centrosomes, which can be reversed by reintroducing wild-type but not NES-mutated NPM. Mutation of a potential proline-dependent kinase phosphorylation site at residue 95, from threonine to aspartic acid (T95D) within the NES motif, abolishes NPM association and inhibition of centrosome duplication. Our results are consistent with the hypothesis that the Ran-Crm1 complex may promote a local enrichment of NPM on centrosomes, thereby preventing centrosome reduplication.

Active Transport, Cell Nucleus↗
PubMed1992

Charcot-Marie-Tooth type 1A duplication appears to arise from recombination at repeat sequences flanking the 1.5 Mb monomer unit.

We have constructed a 3.1 megabase (Mb) physical map of chromosome 17p11.2-p12, which contains a submicroscopic duplication in patients with Charcot-Marie-Tooth disease type 1A (CMT1A). We find that the CMT1A duplication is a tandem repeat of 1.5 Mb of DNA. A YAC contig encompassing the CMT1A duplication and spanning the endpoints was also developed. Several low copy repeats in 17p11.2-p12 were identified including the large (> 17 kb) CMT1A-REP unit which may be part of a mosaic repeat. CMT1A-REP flanks the 1.5 Mb CMT1A monomer unit on normal chromosome 17 and is present in an additional copy on the CMT1A duplicated chromosome. We propose that the de novo CMT1A duplication arises from unequal crossing over due to misalignment at these CMT1A-REP repeat sequences during meiosis.

Base Sequence↗
PubMed1993

A retrospective study comparing duplication and conventionally made complete dentures for a group of elderly people.

The duplication technique is a well recognised method of replacing complete dentures. Advantages claimed for this technique are that patients adapt more easily to their new complete dentures and the numbers of treatment visits are reduced. The case notes of 100 patients were examined retrospectively, 50 of whom had had dentures constructed by undergraduates using a duplication technique and 50 with a conventional technique. In addition, a questionnaire was sent to the patients to obtain their views on the replacement dentures. The 'duplication group' required fewer visits for the delivery of the dentures, but there was no statistical difference between the numbers of post-insertion visits, for the two groups, needed to make the dentures comfortable. The only identifiable reason for selecting a duplication technique was the failure of construction of new dentures by a conventional method in 15 patients. Apart from this the two groups appeared remarkably similar when comparing age of dentures being replaced, period of edentulousness, number of previous complete dentures and medical histories. As judged by the questionnaire more patients in the duplication group continued to wear their new dentures compared to the conventional group.

Aged↗
PubMed2002

Assessment of iodine intake in vegans: weighed dietary record vs duplicate portion technique.

OBJECTIVE: To compare iodine intakes estimated from weighed dietary records with iodine intakes obtained by direct analysis of duplicate diets in a group of vegans. DESIGN: Cross-sectional study. SETTING: London and the south-east of England. SUBJECTS: Thirty-three vegans consuming their habitual diet were recruited through the UK Vegan Society; 26 subjects (11 males, 15 females), age 21-84 y, completed the study. INTERVENTIONS: Iodine intakes were estimated from 4 day weighed dietary records and compared with iodine intakes obtained by direct analysis of concurrent 4 day duplicate diets. RESULTS: There was wide variation in iodine intakes. Mean daily iodine intake in males was significantly lower (P<0.05) when estimated from dietary records (42 microg) compared with that analysed from duplicate diets (137 microg). Conversely, in females the mean daily iodine intake from dietary records (1448 microg) was higher (P=0.43) than from duplicate diets (216 microg). Variation in iodine intakes determined by the two different methods may be attributed to the absence of iodine content of some foods, in particular foods suitable for vegan consumption, in food composition tables and the variability in iodine content of seaweed. CONCLUSIONS: The use of current food tables to estimate iodine intake in vegans is limited. It is not always practical to determine iodine intake using the duplicate portion technique, therefore more reliable information on iodine content of foods, incorporating the variation within foods, is needed.

Adult↗
PubMed1998

Duplication and overexpression of the mutant allele of the MET proto-oncogene in multiple hereditary papillary renal cell tumours.

Previous karyotyping showed a combined trisomy of chromosome 7 and 17 in sporadic and hereditary papillary renal cell tumours (RCT). A recent molecular analysis revealed a mutation in the MET tyrosine kinase (chromosome 7q31) in the germline of four out of seven families with hereditary papillary RCT (HPRCT). We have analysed germline cells as well as multiple tumours obtained from HPRCT families and sporadic cases for alteration of the MET tyrosine kinase and for allelic duplication at chromosome 7 and 17. We have detected a germ line mutation in the MET tyrosine kinase in one of the two families with HPRCTs and also found the same mutation in the germ line of one patient with clinically recognized multiple, bilateral papillary RCTs but without family history. The mutant MET allele is consequently duplicated and overexpressed in tumour cells indicating that duplication of the mutant MET allele is necessary before cells enter the tumorigenic pathway. The lack of germline mutation in two members of another HPRT family and duplication of the same parental allele of chromosome 7 in multiple tumours suggests that a germ line event other than mutation of MET tyrosine kinase is involved in the development of these tumours. Duplication of different alleles of chromosome 7 in sporadic and of chromosome 17 in both types of tumours excludes a germline mutation at these chromosomal sites.

Adenoma↗
PubMed2002

Roles of BRCA1 in centrosome duplication.

Centrosome duplication is under precise control and occurs only once in a normal mammalian cell cycle. Disruption of this process causes centrosome amplification, unequal segregation of chromosomes and, ultimately, tumorigenesis. Recent studies indicate that breast cancer suppressor gene 1 (BRCA1) plays an important role in regulating centrosome duplication. BRCA1 is located in the centrosome and binds to gamma-tubulin. It interacts with a variety of proteins that regulate centrosome duplication, including BRCA2, CDK2-Cyclin A, CDK2-Cyclin E, Gadd45, p21, p53 and Rb. Furthermore, targeted disruption of murine BRCA1 results in centrosome amplification, suggesting that BRCA1 serves as a negative regulator for centrosome duplication. This review will examine these data and discuss possible relationships between BRCA1 and its interacting proteins in centrosome duplication.

Animals↗