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De novo insertion of an Alu sequence in the coding region of the CLCN5 gene results in Dent's disease.

Dent's disease is an X-linked renal tubular disorder characterized by low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and eventual renal failure. Various types of mutations in the renal chloride channel gene, CLCN5, have been identified in patients with this disease. We studied a Spanish patient with Dent's disease and found, by polymerase chain reaction amplification of the CLCN5 exons, an abnormally large exon 11. Sequencing analysis revealed that this was attributable to the insertion in codon 650 of an Alu element of the "young" Ya5 subfamily. The Alu element was inserted with the same orientation as the CLCN5 gene and arose de novo on the maternal chromosome. Polymorphism analysis indicated that the insertion occurred in the germline of the maternal grandfather. The presence of a long poly(A) tract and evidence for a 16-bp target-site duplication implied that the Alu element was integrated by retrotransposition. This mutation predicts a truncated ClC-5 protein that lacks part of the carboxy-terminus and is likely to result in loss of function of the chloride channel. Insertions of Alu sequences, which are rarely found in coding regions, have occasionally been reported to cause other genetic diseases. However, this is the first report of a retrotransposon insertion in the CLCN5 gene associated with Dent's disease.

Alu Elements↗

Transballoon trocar insertion during preperitoneal hernia repair.

Trocar insertion during laparoscopic preperitoneal hernia repair (TEP) can be troublesome because the space into which the trocars are inserted is smaller than that available for transabdominal approaches. Insertion of the trocars directly into the balloon used to dissect the preperitoneal space can facilitate this process. The insertion of a 5-mm trocar into the balloon does not usually result in balloon deflation, and a second trocar can be placed into the balloon as well. Removing the balloon, despite the trocars inside it, is straightforward, allowing the placement of a cannula at the balloon insertion site and initiation of the hernia repair.

Hernia, Ventral↗

Insertion, efficacy, and removal of a nonendoscopically removable percutaneous endoscopic gastrostomy (PEG) tube.

BACKGROUND: Externally removable PEG tubes require an internal bumper that can collapse to a size that is small enough to allow for its removal through the abdominal wall by external traction. Adequate force must be maintained to avoid accidental dislodgement of the tube prior to its desired removal. METHODS: A nonendoscopically removable PEG (Inverta-PEG, Ross Products Division, Abbott Laboratories, Columbus, OH, USA) was evaluated in a nonmasked, prospective clinical study involving 131 patients enrolled by 25 physicians. The over-the-wire (Sacks-Vine) technique was used for all placements. After insertion, patients were followed weekly for 8 weeks. During week 9, the PEGs were removed percutaneously (nonendoscopically). Insertion, efficacy, and removal performance were evaluated. RESULTS: Complication rate during insertion was 1.5% and removal was 1.2%. Qualitatively, investigators rated ease of insertion and removal as very easy, easy, average, difficult, or very difficult. Investigators rated 98.5% of insertions as very easy, easy, or average; 95.4% of removals were rated as very easy, easy, or average. Some patients exited the study prematurely due to leakage around the stoma (2.3%) and inadvertent tube removal (5.3%). These complication rates were consistent with earlier reports of other PEG studies. CONCLUSIONS: These results demonstrate that Inverta-PEG is a safe and effective tube that can be removed nonendoscopically with ease in 95% of the cases.

Adult↗

Implantation of central venous ports with catheter insertion via the right internal jugular vein in oncology patients: single center experience.

AIM OF WORK: Evaluation of suitability and safety of venous port implantation with catheter insertion via the right internal jugular vein in oncology patients. PATIENTS AND METHODS: One hundred one totally implantable venous ports were placed in 100 patients with malignancies from January 1, 2003 until March 31, 2005. Catheter of venous port was preferably inserted via the right internal jugular vein. We recorded a number of successful implantations using this venous approach and the rate of complications during the procedure and follow-up. MAIN RESULTS: Ninety-seven catheters (96%) of totally implantable venous ports were inserted via the right internal jugular vein in 96 patients, and only in four cases were we not able to access this vein. We had no complications related to catheter insertion via the right internal jugular vein. Follow-up was made in all 96 patients with a total access days of 41 in 151 days (mean: 407 days). Premature catheter removal was required in six (6.2%, 0.144 per 1,000 access days) due to complications: three catheter dislocations/malfunctions (3.1%, 0.072 per 1,000 access days), one port-related sepsis, one pocket port infection, and one decubitus over port (1%, 0.024 per 1,000 access days). Six venous ports were removed after completion of the treatment at the patient's request. CONCLUSION: The placement of totally implantable venous ports with catheter insertion via the right internal jugular vein has a high success rate without any early complications. Follow-up also demonstrates a low incidence of late complications requiring port removal.

Adult↗

Safe Veress needle insertion.

BACKGROUND/PURPOSE: For laparoscopic surgery, the creation of pneumoperitoneum still remains a must. The insertion of a Veress needle or a trocar is never perfectly safe, and almost every kind of intraabdominal organ injury due to these insertions has been reported worldwide. Here, we describe a safe technique for creating pneumoperitoneum. METHODS: For the creation of pneumoperitoneum, under direct vision, the linea alba was elevated with two towel clips and then the Veress needle was inserted. We reviewed 368 patients operated on with this technique for complication rates. Ultrasound images were obtained before and during abdominal-wall lifting in 10 patients. RESULTS: There were no injuries due to the insertion of the Veress needle or trocars. In 90% of the patients, pneumoperitoneum was created successfully on the first attempt. Ultrasound examination demonstrated a mean extra safe area of 11.8 mm during abdominal-wall lifting with this technique. CONCLUSIONS: Elevating the linea alba during Veress-needle insertion is safe.

Abdominal Wall↗

Computer analysis of the safety of using three different pedicular screw insertion points in the lumbar spine in the Chinese population.

To help decide the best starting point for lumbar spine pedicle screw insertion in the Chinese population using three different techniques (Roy-Camille, Magerl, and Du). Three-dimensional CT reconstructions were created from 40 adult lumbar vertebral segments. Three different starting points for lumbar pedicle screw insertion were used. The direction of the pedicle screw through each hole was simulated on three-dimensional reconstructed images. Precise CT measurements were made to assess the distance from the simulated screw and the medial and lateral pedicle walls at the smallest transverse section of each pedicle. To measure a pedicle transverse section angle (TSA) lines were drawn on a CT scan in the direct axis of the pedicle, tangential to the medial, and separately lateral, walls of the pedicles at the isthmus. The angle these lines made with an anterior to posterior line, which directly bisected the mid-portion of the vertebral body was called the TSA. The greater the difference between the TSA between the medial and lateral walls provides the greatest flexibility for the insertion angle of the pedicle screw. Additionally, the distance from a line drawn in the direct central axis of the pedicle was measured from the point of exit from the pedicle to the entry point of each of three insertion techniques (Du, Mageral, and Roy-Camille), to help understand potential risk factors. There were statistically significant differences between the distances from the entrance point to the direct pedicle axis among the three methods (P < 0.001). Du's insertion point was the shortest from L1 to L4. The distances measured following Magerl's technique were shortest at L5 (P < 0.05). There was no significant difference of the safe range of the TSA between the three methods from L1 and L2 (P > 0.05), but significant differences at L3, L4, and L5 (P < 0.05). At L3 and L4 the safe ranges of TSA using Du and Magerl's methods were significantly larger than those measured by Roy-Camille (P < 0.05). At L5 the safe ranges of TSA for the Magerl technique were the greatest among the three methods (P < 0.05). These results demonstrate that Du's method provides the safest starting point to place pedicle screws from L1 to L4, as its distance from the entrance point to the pedicle axis is the shortest and the safe range of TSA the largest of the three techniques. Magerl's technique can be safely used in the pedicles from L3 to L5, and is the safest choice at L5. Roy-Camille's technique is most applicable at L1 and L2, but has the highest risk when applied from L3 to L5.

Adult↗

Duplex directed caval filter insertion in multi-trauma and critically ill patients.

This study was undertaken to determine the safety and feasibility of inferior vena cava (IVC) filter insertion at the bedside using duplex imaging in multi-trauma and/or critically ill patients. From February 1996 to August 1997, 53 multi-trauma and/or critically ill patients, who were in the intensive care unit and referred for an IVC filter, were prospectively evaluated for possible duplex directed caval filter (DDCF) insertion. Screening IVC duplex scans were performed in all patients. Satisfactory ultrasound visualization in 46 patients (87%) allowed attempted DDCF insertion. All procedures were percutaneously performed at the bedside using Vena Tech IVC filters. The results from this series showed that DDCF insertion can be safely and rapidly performed at the bedside in multi-trauma or critically ill patients. The procedure is dependent on satisfactory visualization of the IVC by duplex ultrasonography, which was possible in 45 out of 53 (85%) patients. Insertion at the bedside substantially reduces the procedural cost and avoids the need for transport, radiation exposure, and intravenous contrast.

Critical Illness↗

The Alu insertion in the CLCN5 gene of a patient with Dent's disease leads to exon 11 skipping.

Alu sequences are short, interspersed elements that have generated more than one million copies in the human genome. They propagate by transcription followed by reverse transcription and integration, causing mutations, recombination, and changes in pre-mRNA splicing. We have recently identified a 345-bp long Alu Ya5 element inserted in codon 650 within exon 11 of the chloride channel ClC-5 gene (CLCN5) of a patient with Dent's disease. A microsatellite pedigree analysis indicated that the insertion occurred in the germline of the maternal grandfather. Dent's disease is an X-linked renal tubular disorder characterized by low-molecular-weight proteinuria, hypercalciuria, nephrolithiasis, and nephrocalcinosis. Here, we found, by RT-PCR amplification of RNA extracted from the patient's blood and subsequent DNA sequencing, that the Alu insertion led to an aberrant splicing of the CLCN5 pre-mRNA that skipped exon 11. Using the ESE finder and RESCUE-ESE Web interfaces, we identified two high-score exonic splicing enhancer (ESE) sequences in the site of insertion. The functional significance of these ESE motifs is suggested by our observation that these sequences are highly conserved among mammal CLCN5 genes. Therefore, we suggest that the Alu insertion causes exon skipping by interfering with splicing regulatory elements. The altered splicing would predict a truncated ClC-5 protein that lacks critical domains for sorting and chloride channel function.

Alternative Splicing↗

Stability of Potato virus X expression vectors is related to insert size: implications for replication models and risk assessment.

We investigated the stability of expression constructs based on Potato virus X (PVX) as a function of insert length. Five different inserts ranging in length from 261 to 1,758 bp (human proinsulin, murine interleukin-10, HIV-1 nef, petunia expansin-1 and human gad65) were expressed using a PVX vector in Nicotiana benthamiana plants for three sequential passages. Using a competitive RT-PCR approach we demonstrated that insert-deletion could occur in the first infection cycle for all inserts, but that this was much more likely to be the case for longer ones. This suggested a negative correlation between insert length and vector stability. Sequence analysis of the deleted constructs suggested that recombination usually occurred at sites close to the duplicated sub-genomic promoter, but in a smaller number of cases the foreign gene itself was probably involved, resulting in partially deleted constructs containing transgene fragments. The implications of these results in the context of recombinant protein expression and its risks are discussed.

Animals↗

Percutaneous intraaortic balloon insertion.

A new single chambered percutaneous intraaortic balloon has been constructed around a central guidewire. The balloon can be wrapped around the guidewire, enabling its insertion into the femoral artery through a 12F sheath inserted with the conventional Seldinger technique. Percutaneous intraaortic balloon insertion has been performed in 27 patients (mean age 58 years) for a variety of medical and surgical indications. Percutaneous balloons could not be advanced into the aorta in two patients (7.4 percent) with severe bilateral aortoiliac occlusive disease. In all 25 patients undergoing intraaortic balloon pumping satisfactory circulatory support was achieved, and 21 (84 percent) of the patients survived to be discharged from the hospital. The mean duration of intraaortic balloon pumping was 3.5 days. Percutaneous intraaortic balloon insertion requires less than 5 minutes and has been successfully performed in the cardiac catheterization laboratory, coronary care unit, operating room and recovery room. After direct balloon removal, external pressure was applied for 30 minutes. No patient experienced hematoma of the groin, aortic dissection, compromised distal pulses or late wound complications. Percutaneous balloon insertion permits the rapid institution of circulatory support and broadens the medical and surgical applications of intraaortic balloon pumping.

Adult↗

Defatting catheter insertion sites in total parenteral nutrition is of no value as an infection control measure. Controlled clinical trial.

Defatting the skin with acetone or ether is widely used in the regimen for disinfection of insertion sites of central venous catheters in total parenteral nutrition. The fatty acids secreted by normal skin play an important role in regulation of the cutaneous microbial ecosystem, and it can be questioned whether application of a solvent might paradoxically promote colonization by pathogenic microorganisms. The clinical value of defatting catheter insertion sites was prospectively studied in a controlled, randomized trial: 100 subclavian catheters inserted for total parenteral nutrition were given identical site care except that with one half of the catheters, the site was defatted with acetone prior to catheter insertion and as part of the every-other-day site care regimen. Cutaneous colonization was found in only 130 (24.5 percent) of 531 site cultures in both groups, but was strongly predictive of concordant colonization of the catheter (relative risk, 22.1, p less than 0.001) and catheter-related septicemia (all four cases). No significant differences were observed between the two groups in cutaneous colonization of sites (22.7 percent and 27.0 percent), in colonization of catheters on removal (four catheters [8 percent] in each group) or in catheter-related septicemia (two catheters [4 percent] in each group). However, pain or inflammation of the insertion site was twice as frequent in the acetone group (80 percent versus 35 percent, p less than 0.001). Defatting with acetone as part of the regimen for cutaneous disinfection does not improve microbial removal or reduce the incidence of catheter-related infection, but increases cutaneous inflammation and patient discomfort.

Acetone↗

Microbial colonization of tailed and tailless intrauterine contraceptive devices: influence of the mode of insertion in the rabbit.

An experimental rabbit model was developed to study the microbial colonization of intrauterine contraceptive devices. Tailed and tailless devices were surgically inserted into into the uterus by two different routes: surgically, directly into the uterine horn, thus avoiding contact with the vaginal and cervical microfloras, or via the vagina and cervix. After 1 to 8 weeks the devices were recovered and prepared for scanning electron microscopy. The surfaces of surgically inserted devices remained uncolonized all through the experiment whereas in those inserted via the cervix microorganisms colonized the core surface as early as 2 weeks after insertion. Our data suggest that in our experimental conditions the mode of insertion appears to be the major factor influencing the microbial colonization of intrauterine contraceptive devices and that the presence of a tail does not seem to play a significant role.

Animals↗

Correct oligomerization is a prerequisite for insertion of the central molecular domain of staphylococcal alpha-toxin into the lipid bilayer.

Staphylococcal alpha-toxin is a primarily hydrophilic molecule that binds as a monomer to target membranes and then aggregates to form amphiphilic oligomers that represent water-filled transmembrane channels. Current evidence indicates that a region located in the center of the molecule inserts deeply into the bilayer. In the present study, we sought to determine whether membrane insertion was triggered by the oligomerization process, and whether insertion correlated with pore formation. Double mutants of alpha-toxin were prepared in which His-35 was replaced by Arg, and cysteine residues were introduced at positions 69, 130 and 186. Substitution of His-35 with Arg rendered the toxin molecules incapable of proper oligomerization, so that they remained in nonlytic form after binding to membranes. The sulfhydryl groups were labelled with the polarity-sensitive fluorescent dye acrylodan. Functionally intact, single mutant toxins containing only the cysteine residues were utilized as controls. Measurements of the fluorescence emission spectrum of acrylodan were performed for the active and inactive alpha-toxin mutants in free solution and in membrane-bound form. The collective results demonstrate that proper oligomerization is required for membrane insertion of the central region in the alpha-toxin molecule, and that lack of insertion correlates with absence of pore formation.

2-Naphthylamine↗

Effect of cholesterol on the tight insertion of cytochrome b5 into large unilamellar vesicles.

When cytochrome b5 is added to large unilamellar vesicles (LUVs) of 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), it binds predominantly in a 'loose,' or transferable form. Prolonged incubation of 30 degrees C leads to insertion in the physiological 'tight,' nontransferable form, with a halftime for the loose --> tight conversion of approx. 9 days. In this study, the effect of cholesterol on the rate of tight insertion was determined. Tight binding was assayed by depleting the LUVs of loose cytochrome b5 with an excess of SUV acceptors and then separating the liposome populations by gel-filtration or velocity sedimentation. Incorporation of cholesterol into the LUVs was found to markedly increase the rate of tight insertion, even though cholesterol decreases the equilibrium binding constant and saturation level of protein binding. The effect is not a continuously increasing function of cholesterol content, but attains a maximum at 20-25% mol%, where the rate enhancement is approx. 10-fold over baseline. At higher cholesterol levels, the rate decreases, returning to baseline at 40 mol% cholesterol. These observations are highly unusual in that cholesterol generally decreases the membrane binding affinity and the permeability of solutes, and does so as a monotonic function of cholesterol concentration (above the liquid-crystalline phase transition of the phospholipids). It is suggested that tight insertion is enhanced by lipid-protein packing mismatches and by bilayer fluidity; the former increases monotonically with increasing cholesterol whereas the latter decreases monotonically. At 20-25 mol% cholesterol the optimum balance of these physical properties is obtained for tight insertion.

Centrifugation, Density Gradient↗

Electro-insertion of xeno-glycophorin into the red blood cell membrane.

The electroporation technique, with field strengths slightly below the critical value Ec for electroporation of red blood cells (RBC), enables the insertion of xeno-proteins into the RBC membrane without damaging the cells. The electro-insertion has been used to insert biotinylated human glycophorin into human RBC membrane and human glycophorin into murine RBC membrane. Binding anti-human glycophorin antibody (10F7) to the murine RBC bearing human glycophorin indicates extracellular orientation of inserted glycophorin. Insertion of about 10(5) glycophorin molecule per cell has been estimated by whole cell ELISA.

Animals↗

Insertion site complications during the first year of NORPLANT use.

Although review articles have provided much information on the NORPLANT system, information on insertion site complications based on multi-country trials has been limited to infection rates. This paper examines 2,674 NORPLANT acceptors from seven countries who were enrolled and followed for one year. The one-year incidence rates of infection (0.8%), expulsion (0.4%) and local reaction (4.7%) varied widely among countries and clinics within a country. In contrast to previous reports that insertion site complications occur during the first few weeks of use, these data show that a substantial proportion of insertion site infections (34.6%) and implant expulsions (64.3%) were reported after the first two months of use, while 35.7% of local reactions were reported after 4.5 months of use. Of the 16 women with infections who did not have the implants immediately removed, 8 eventually required or requested removal, indicating that the ICCR recommendation for immediate removal in case of infection appears appropriate. An awareness of the frequency of insertion site complications, distribution of the time of onset post-insertion and potential sequelae of complications will aid clinicians in better client counseling and complication management.

Adult↗

Insertions of palindromic DNA sequences into the J-F intercistronic region of bacteriophage phi X174 interfere with normal phage growth.

The effect of hairpin (cruciform) size on the regulation of gene expression was investigated by cloning a series of palindromic sequences into the non-essential J-F intercistronic region of the bacteriophage phi X174 ins6 genome. Genetic stability of the insert sequence and its effect on the growth efficiency of the phage was used as an initial measure of the biological consequence of hairpin insertions. Multimers of increasing size of the BamHI linker sequence C-C-G-G-A-T-C-C-G-G were inserted into the PvuII site of the parental strain ins6. The largest hairpin that could be constructed and maintained in the phi X174 genome had a stem length of 22 base-pairs and a loop size of four nucleotides (linker tetramer). However, this structure proved to be disadvantageous to the phage and was rapidly deleted from its genome. Trimer inserts were more stable, but were eventually deleted also. Monomer and dimer inserts, though genetically stable, decreased the growth efficiency of the phage as judged by competitive growth experiments and measurements of burst size. The physical formation of these hairpins was shown by restriction digests of single-stranded DNA with BamHI and HpaII. We argue that these secondary structures form in vivo, at least in the single-stranded genome and the polycistronic mRNAs, and were responsible for the observed growth defects.

Bacteriophage phi X 174↗

Insertion of the SfMNPV polyhedrin gene into an AcMNPV polyhedrin deletion mutant during viral infection.

The Autographa californica nuclear polyhedrosis virus (AcMNPV) polyhedrin deletion mutant, d10A, was cotransfected with the recombinant plasmid SfMNPV.HindIII-L, which contains the Spodoptera frugiperda nuclear polyhedrosis virus (SfMNPV) polyhedrin gene. An occlusion-positive hybrid virus was obtained which contained a DNA insertion at approximately 13 map units on the AcMNPV.d10A genome. A fine structure restriction map of cloned viral DNA fragments from this region revealed that most of the 1.7-kb AcMNPV.PstI-O fragment (13.4-14.7 map units) had been replaced with a 3.7-kb fragment, containing the SfMNPV polyhedrin gene with flanking sequences and the entire pUC8 plasmid. Subclones of this region were sequenced and the exact site of insertion was determined. Flanking the insert were 43 and 60 bp of unknown origin at the 5' and 3' ends, respectively. Transcription was examined in the region of the insertion in both wild-type AcMNPV and the AcMNPV/SfMNPV (Ac/Sf) hybrid. In the AcMNPV, a nested set of seven overlapping transcripts ranging from 2.2 to 5.3 kb was found, each with coterminal 3' ends. Only the 2.2-kb transcript was found to be expressed early and throughout infection. The SfMNPV insertion interrupted this transcriptional unit and produced a more complex pattern of transcription. Alterations included a nested set of three overlapping transcripts with coterminal 5' ends, including the SfMNPV polyhedrin mRNA, transcripts originating in AcMNPV and terminating in either SfMNPV or pUC8 sequences, and other minor transcripts. The SfMNPV polyhedrin gene was sequenced and the locations of the 5' and 3' ends of polyhedrin mRNA were mapped. An analysis of SfMNPV polyhedrin protein expression showed that the SfMNPV polyhedrin gene in the hybrid virus was expressed at approximately one-fourth the level of the wild-type AcMNPV polyhedrin gene. Expression of a beta-galactosidase gene under the control of the SfMNPV polyhedrin promoter in the AcMNPV.d10A mutant was also investigated.

Amino Acid Sequence↗