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At least 865 records · Page 48Linked to original sources
PubMed2001

Unusual duplication of appendix and cecum: extension of the Cave-Wallbridge classification.

Duplicated appendix has, to date, been classified into 3 types. The authors present a type of duplicated appendix not previously described. Surgical exploration was done in a 14-year-old girl who had an acute abdomen. Surgical exploration showed a duplicated appendix that arose from the normal appendix and ended in a thick-walled, inflamed, perforated muscular pouch. Duplicated appendix is a treatable condition that rarely occurs with colonic duplication and which should be considered in the differential diagnosis of lower abdominal pain.

Abdomen, Acute↗
PubMed2002

An unusual presentation of Y-type urethral duplication with perianal abscess: case report.

Urethral duplications are rare anomalies that manifest in various anatomic forms. These variations are classified broadly as epispadic, hypospadic, and Y-type duplications. In the Y-type, the accessory ventral channel opens into either the perineum or the anal canal. Typically, the dorsal urethra is hypoplastic, and the external meatus is stenotic, so urine is voided through the dominant ventral channel. In the other unusual form, the dorsal urethra is normal and perineal or rectal opening of accessory ventral urethra is an accidental finding. When treating patients with typical Y-type duplications, the accessory ventral urethra is mobilized and then is carried to the glans with one- or 2-stage urethroplasty. In the unusual form, excision of the anterior urethra is the definitive surgical treatment. This report describes a case of unusual Y-type urethral duplication in which the accessory ventral channel had a stenotic perianal opening. The patient developed recurrent attacks of perianal abscess associated with urinary tract infections. To the authors' knowledge, this is the first reported case of Y-type duplication with an hypoplastic accessory ventral channel that was presented with recurrent perianal abscess attacks.

Abscess↗
PubMed2003

Congenital prepubic sinus: an epispadiac variant of urethral duplication: case report and review of literature.

Urethral duplication is rare; the duplicated urethra is almost always dorsal to the normal urethra, which contains the sphincteric mechanism. It is very rare to present as a prepubic sinus. Urethral duplication does not represent a uniform entity making it difficult to find an unequivocul and comprehensive classification. A case of epispadiac variant of urethral duplication is reported in which the duplicated urethra presents as a prepubic sinus, with complete cure and normal urinary and sexual functions after maturity.

Child, Preschool↗
PubMed2001

Duodenal duplication with pancreas bifidum--a case report.

Duodenal duplications constitute less than five percent of gastrointestinal duplications. Rarely, enteric duplication cysts are found in an intra- or juxtapancreatic position with or without connection to the pancreatic duct. Complete pancreaticoduodenal duplication is even less common, although there is a close relationship in the development of the two organs. We report here the case of a child with a paraduodenal cystic lesion, followed up since infancy, which turned out to be duodenal duplication cyst with a connection to Wirsung's duct of the ventral pancreas.

Duodenal Obstruction↗
PubMed1983

Segmental colonic duplication presenting as a sigmoid volvulus.

This is a case report of a four-year-old girl who presented with severe intermittent abdominal pain. She had an infra-levator imperforate anus repaired as a newborn. Operation demonstrated duplications of the right and left colons, separated by a normal transverse colon. The left colon duplication was closed at both ends, and it contained 500 cc of intestinal secretions. The sigmoid colon and its duplication volvulized. The terminal ileum was also duplicated; one ileum joining a normal ascending colon duplication, which was patent proximally, but closed distally.

Child, Preschool↗
PubMed1974

Constitutive expression of bacteriophage P2 early genes resulting from a tandem duplication.

A tandem-duplication mutant of bacteriophage P2 was isolated. Physically, its particles are characterized by a higher buoyant density and lower heat stability than the wild type, both consequences of increased DNA content. Genetically, the mutant is easily recognized by its insensitivity to control by the immunity-specific repressor. The duplication covers part of gene B, necessary for phage DNA replication. To explain the immunity-insensitivity of the duplication it is proposed that the promoter, but not the operator site, in the early gene operon is duplicated in this mutant. By crosses with a gene-B mutant, a recombinant carrying a heterozygous duplication was isolated.

Centrifugation, Density Gradient↗
PubMed1985

Isolation of a gene enhancer within an amplified inverted duplication after "expression selection".

We have attempted to isolate and identify cellular expression sequences from F9 teratocarcinoma DNA by utilizing their ability to reactivate a selectable gene devoid of its own expression sequences (expression selection). Restriction nuclease-digested F9 cellular DNA was ligated to a polyoma virus (Py) DNA fragment which contains an intact transforming region but is incapable of inducing transformation because it lacks the viral 5' enhancer sequence. The ligation mixture was used to transfect Rat-1 cells and a transformed cell line, 3B, was isolated. The 3B cell line contained a single type of Py DNA insert, which was molecularly cloned as an 18-kilobase BglII fragment. A weak cellular enhancer was identified in a 4.7-kilobase BamHI fragment upstream from the Py sequences. Both the Py DNA and the enhancer sequences were found to be present in an inverted duplication in the 3B clone. The presence of this structure in 3B genomic DNA was confirmed by the analysis of selectively isolated inverted duplicated sequences, and the structure was found to be at least 22 kilobases long. In the 3B cell line, the inverted duplicated sequences containing the Py and enhancer sequences are quite stable and are amplified 20- to 40-fold. The strongly transformed phenotype of the 3B cells may be a result of this amplification. The formation of inverted duplications as a part of the amplification mechanism as well as a general strategy for the cloning of inverted duplicated (amplified) sequences is discussed.

Animals↗
PubMed1985

Transposable element IS1 intrinsically generates target duplications of variable length.

Target duplication during transposition is one of the characteristics of mobile genetic elements. IS1, a resident insertion element of Escherichia coli K-12, was known to generate a 9-base-pair target duplication, while an IS1 variant, characterized by a nucleotide substitution in one of its terminal inverted repeats, was reported to duplicate 8 base pairs of its target during cointegration. We have constructed a series of transposons flanked by copies of either the normal or the variant IS1. The analysis of their transposition products revealed that transposons with normal termini as well as those with variant termini can intrinsically generate either 9- or 8-base-pair target duplications. We also observed that a normal IS1 from the host chromosome generated an 8-base-pair repeat. The possible relevance of the observation for the understanding of transposition processes and models to explain the variable length of target duplications are discussed.

Base Sequence↗
PubMed1993

Duplication of the CD8 beta-chain gene as a marker of the man-gorilla-chimpanzee clade.

In earlier studies we have found that the gene encoding the CD8 beta chain is duplicated in man. We demonstrate here that the duplicated genes are both located on chromosome 2. We have also studied the moment of the duplication event relative to the evolution of higher primates by using genomic DNA of a panel of primates. Our data strongly suggest that duplication occurred after the orangutan lineage had split and before the chimpanzee, gorilla, and man clade diverged, some 8-9.5 million years ago. This result makes the CD8 beta-chain gene duplication a convenient marker for the study of the evolution of higher primates.

Animals↗
PubMed1995

Tandem sequence duplications functionally complement deletions in the D1 protein of photosystem II.

Obligate photoheterotrophic mutants of the cyanobacterium Synechocystis sp. PCC 6803 that carry deletions of conserved residues in the plastoquinone-binding niche of the D1 protein were used to select for spontaneous mutations that restore photoautotrophic growth. Spontaneous pseudorevertants emerged from two deletion mutants, delta YNIV246-9 and delta NN266-7, when the cultures were maintained long after the carbon source (glucose) had been depleted from the medium and cells had reached stationary phase. Most pseudorevertants were found to contain tandem duplications of 6-45-base pair DNA sequences located close to the domain carrying the deletion; none of them restored the wild-type sequence. Three pseudorevertants isolated from the delta YNIV246-9 mutant contained a duplication (7-15 codons) of the DNA sequence immediately downstream of the deletion; the protein region encoded by this DNA may include part of the putative de helix, an important constituent of the plastoquinone-binding niche. Three pseudorevertants isolated from the delta NN266-7 mutant contained duplications corresponding to 2-8 amino acid residues adjacent to the site of the deletion. In all six pseudorevertants carrying duplications, the length of the D1 protein in the modified regions was restored to at least the length present in wild type, suggesting that a minimal length of these protein domains may be required for functional integrity. In another photoautotrophic strain isolated from delta NN266-7, no secondary mutations could be identified in the gene coding for the D1 protein; such mutations apparently reside on another protein subunit of the photosystem II complex. Photosystem II function in the pseudorevertants was altered as compared with wild type in terms of growth and oxygen evolution rates, photosystem II concentration, the semiquinone equilibrium at the acceptor side, and thermostability. A mechanism leading to tandem sequence duplication may involve DNA damage followed by DNA synthesis, strand displacement, and ligation.

Amino Acid Sequence↗
PubMed2001

Specific phosphorylation of nucleophosmin on Thr(199) by cyclin-dependent kinase 2-cyclin E and its role in centrosome duplication.

The kinase activity of cyclin-dependent kinase 2 (CDK2)-cyclin E is required for centrosomes to initiate duplication. We have recently found that nucleophosmin (NPM/B23), a phosphoprotein primarily found in nucleolus, associates with unduplicated centrosomes and is a direct substrate of CDK2-cyclin E in centrosome duplication. Upon phosphorylation by CDK2-cyclin E, NPM/B23 dissociates from centrosomes, which is a prerequisite step for centrosomes to initiate duplication. Here, we identified that threonine 199 (Thr(199)) of NPM/B23 is the major phosphorylation target site of CDK2-cyclin E in vitro, and the same site is phosphorylated in vivo. NPM/T199A, a nonphosphorylatable NPM/B23 substitution mutant (Thr(199) --> Ala) acts as dominant negative when expressed in cells, resulting in specific inhibition of centrosome duplication. As expected, NPM/T199A remains associated with the centrosomes. These observations provide direct evidence that the CDK2-cyclin E-mediated phosphorylation on Thr(199) determines association and dissociation of NPM/B23 to the centrosomes, which is a critical control for the centrosome to initiate duplication.

3T3 Cells↗
PubMed1997

Single or duplicate analysis for automated prothrombin time and activated partial thromboplastin time?

The introduction of automated coagulation analysers raises the possibility of performing routine coagulation tests as single rather than duplicate analyses. This study compares the duplicate results of the prothrombin time (PT) and activated partial thromboplastin time (aPTT) to that of a single result obtained by the MLA Electra 1000c using two different methods. The first method looks specifically at the difference between the mean duplicate result and the single result to determine if they alter patient management. This method found that two of 4152 PTs (0.048%) and two of 3047 aPTTs (0.065%) were clinically significant. The second method statistically assessed the agreement between the traditional mean duplicate result and the single test. This supported the introduction of single testing as the calculated 95% confidence intervals demonstrate that each result is interchangeable for purposes of clinical interpretation. These results supported the introduction of single testing for PT and aPTT estimation in our laboratory. The introduction of single testing was accompanied by changes to quality control and machine maintenance to ensure that the functions previously covered by duplicate testing were maintained. A strict protocol for repeat testing has also been adopted.

Australia↗
PubMed2005

Successful endoscopic treatment of an esophageal duplication cyst.

Duplication cysts of the gastrointestinal tract are rare, particularly in adults. Endoscopic minimally invasive treatment is still a challenging approach even in the endoscopically accessible sections of the gastrointestinal tract. In a 25-year-old patient suffering from dysphagia, an endoscopy and subsequent endosonography revealed a spherical duplication cyst in the lower third of the esophagus, which prompted us to puncture the cyst and subsequently to perform a fenestration (marsupialization; diameter 1 cm) in the anterior wall of the cyst, resulting in permanent drainage of the cystic fluid. Because of the recurrent complaints of the patient after 6 weeks, the anterior wall of the duplication cyst, the former esophageal wall, was partially resected, resulting in a permanent 4-cm opening including the cystic cavity into the esophageal lumen. Thereafter, there were no further complaints from the patient and the findings in the follow-up endoscopy were normal. A successful endoscopic intervention for this type of gastrointestinal duplication cyst is described for the first time. The minimally invasive resection of the anterior wall of the esophageal duplication cyst, simultaneously with the former regular wall at this segment of the esophagus, resulted in permanent inclusion of the cystic cavity into the esophageal lumen with no disadvantageous passage of fluid and food through the lower esophagus or changes in the former cystic epithelium. This method is considered to be feasible and a reasonable treatment alternative to the more invasive surgical approach.

Adult↗
PubMed1996

The Saccharomyces cerevisiae spindle pole body duplication gene MPS1 is part of a mitotic checkpoint.

M-phase checkpoints inhibit cell division when mitotic spindle function is perturbed. Here we show that the Saccharomyces cerevisiae MPS1 gene product, an essential protein kinase required for spindle pole body (SPB) duplication (Winey et al., 1991; Lauze et al., 1995), is also required for M-phase check-point function. In cdc31-2 and mps2-1 mutants, conditional failure of SPB duplication results in cell cycle arrest with high p34CDC28 kinase activity that depends on the presence of the wild-type MAD1 checkpoint gene, consistent with checkpoint arrest of mitosis. In contrast, mps1 mutant cells fail to duplicate their SPBs and do not arrest division at 37 degrees C, exhibiting a normal cycle of p34CDC28 kinase activity despite the presence of a monopolar spindle. Double mutant cdc31-2, mps1-1 cells also fail to arrest mitosis at 37 degrees C, despite having SPB structures similar to cdc31-2 single mutants as determined by EM analysis. Arrest of mitosis upon microtubule depolymerization by nocodazole is also conditionally absent in mps1 strains. This is observed in mps1 cells synchronized in S phase with hydroxyurea before exposure to nocodazole, indicating that failure of checkpoint function in mps1 cells is independent of SPB duplication failure. In contrast, hydroxyurea arrest and a number of other cdc mutant arrest phenotypes are unaffected by mps1 alleles. We propose that the essential MPS1 protein kinase functions both in SPB duplication and in a mitotic checkpoint monitoring spindle integrity.

CDC28 Protein Kinase, S cerevisiae↗
PubMed1960

Deoxyribonucleic acid synthesis in relation to duplication of centers in dividing eggs of the sea urchin, Strongylocentrotus purpouratus.

The earliest known event in the sequence leading to mitosis is the duplication of cell centers. The present investigation shows that the synthesis of DNA, although closely following it in time, is initiated entirely independently of this prior event. Fertilized eggs of the sea urchin, S. purpuratus, were exposed to beta-mercaptoethanol at intervals during development. This substance, when introduced at appropriate times, blocks mitosis and also prevents duplication of centers. Whether or not duplication of centers had already occurred before introduction of the blocking agent was determined by observing the division patterns of eggs after the mercaptoethanol was removed: division of one cell into two, or of two into four indicated that duplication had not occurred; division of one into four or of two into eight, that it had. Incorporation of H(3)-labeled thymidine into DNA, as demonstrated by autoradiography, showed that DNA synthesis took place during the mercaptoethanol block regardless of whether or not the centers had already duplicated. Thus the two major reproductive events of the mitotic sequence, although normally coordinated in time, can be dissociated experimentally and shown to function independently.

Animals↗
PubMed1999

A chromosomal duplication map of malformations: regions of suspected haplo- and triplolethality--and tolerance of segmental aneuploidy--in humans.

The distribution of simple autosomal duplications associated with congenital malformations has been analyzed by means of data contained in the Human Cytogenetics Database. For each of the 47 malformations, the frequency of duplication of a given chromosome band associated with the malformation was compared with the overall frequency of duplication of that band recorded in the database. In total, there were 143 malformation-associated chromosomal regions (MACR); 21 of these contained at least one band with a highly significant (P<.001) association. The average number of bands per MACR was 3.1. Eight bands, representing 2.1% of haploid autosomal length, were not involved in any duplication, and we suggest that these are potentially triplolethal. This compares with 31 bands, representing 11% of haploid autosomal length, that were identified in the previously reported deletion map and that were not involved in any deletion and are potentially haplolethal. In both cases, approximately half of these bands are pericentromeric. The longest duplication involves 4.3% of haploid autosomal length, and the longest deletion involves 2.7%.

Chromosome Aberrations↗
PubMed2003

Experimental study of the efficiency of lithotripsy with duplicate pulses.

BACKGROUND AND PURPOSE: Theoretical study had shown that compared with a single pulse, a duplicate pulse could improve the efficiency of lithotripsy. We conducted a series of studies to validate this idea. MATERIALS AND METHODS: The experimental study in vitro and in vivo used a lithotripsy machine with duplicate, single, and electromagnetic pulses. RESULTS: Use of a duplicate pulse improved the wastage of the model stones about 44.15% and the efficiency of lithotripsy about 44.76%. In pigs, the efficiency of lithotripsy was greater with a duplicate pulse than with single and electromagnetic pulses. CONCLUSION: Compared with single and electromagnetic pulses, duplicate pulses could improve the efficiency of lithotripsy by more than 40%.

Animals↗
PubMed2003

Duplication models for biological networks.

Are biological networks different from other large complex networks? Both large biological and nonbiological networks exhibit power-law graphs (number of nodes with degree k, N(k) approximately k(-beta)), yet the exponents, beta, fall into different ranges. This may be because duplication of the information in the genome is a dominant evolutionary force in shaping biological networks (like gene regulatory networks and protein-protein interaction networks) and is fundamentally different from the mechanisms thought to dominate the growth of most nonbiological networks (such as the Internet). The preferential choice models used for nonbiological networks like web graphs can only produce power-law graphs with exponents greater than 2. We use combinatorial probabilistic methods to examine the evolution of graphs by node duplication processes and derive exact analytical relationships between the exponent of the power law and the parameters of the model. Both full duplication of nodes (with all their connections) as well as partial duplication (with only some connections) are analyzed. We demonstrate that partial duplication can produce power-law graphs with exponents less than 2, consistent with current data on biological networks. The power-law exponent for large graphs depends only on the growth process, not on the starting graph.

Internet↗