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PubMed1987

Percutaneous insertion of the Kimray-Greenfield filter: technical considerations and problems.

Kimray-Greenfield filters were inserted percutaneously into the inferior vena cava (IVC) in 57 patients. Thirty-six were placed from the right femoral vein, 14 from the left femoral vein, and seven from the right internal jugular vein. There were no deaths or major complications and only six minor complications. Inferior vena cavography was done before filter insertion in all cases. Cavography is vital to determine feasibility of filter insertion, route of insertion, and filter location; pertinent findings include caval size, presence or absence of clot in the IVC or iliac veins, and position of the renal veins. The guide wire provided with the standard filter introduction set has a tendency to catch on the filter as the wire is withdrawn. A stiff wire with a straight, tapered, floppy tip was substituted. The femoral approach is preferred when it is feasible. Though there was only one known occurrence of femoral vein thrombosis at the filter insertion site, other cases may have occurred and may not have been detected. If the frequency of this complication proves to be significant, the preferred route for filter insertion may have to be reconsidered.

Femoral Vein↗
PubMed1997

NH2-terminal-inserted myosin II heavy chain is expressed in smooth muscle of small muscular arteries.

We demonstrate, using reverse transcriptase-polymerase chain reaction, that, whereas abdominal aorta from rabbit consists almost entirely of myosin heavy chain (MHC) mRNA with no insert at the 5'-terminal coding region, the distributing arteries (femoral and saphenous) begin to show MHC mRNA with the 21-nucleotide insert that encodes seven amino acids in the ATP-binding region located in the myosin head. The femoral/iliac artery contains > 50% inserted mRNA, whereas the more distal saphenous artery contains > 80% inserted mRNA. This insert is also present in the smooth muscle from rat tail artery but is absent in the smooth muscle from rat aorta. The actin-activated ATPase activity of myosin from the rabbit femoral/saphenous artery is 1.7-fold higher than that of the myosin from the aorta. A concomitant increase (about twofold) in the maximum shortening velocity of the saphenous artery, compared with that of the aorta, indicates that the preponderance of the inserted myosin is associated with both an increase in the actin-activated ATPase activity and a larger maximum velocity of shortening. Furthermore, analysis of the 17-kDa essential light chain from the aorta reveals near equal quantities of the 17-kDa light chain isoforms a and b, whereas the myosin from the femoral/ saphenous artery contains predominantly the 17-kDa light chain a isoform. Together, these data indicate that the smooth muscle cells from the small distributing arteries are similar to those of visceral smooth muscle with respect to the expression of myosin isoforms, actin-activated myosin ATPase activity and contractility.

Adenosine Triphosphatases↗
PubMed2006

The genomic distribution of L1 elements: the role of insertion bias and natural selection.

LINE-1 (L1) retrotransposons constitute the most successful family of retroelements in mammals and account for as much as 20% of mammalian DNA. L1 elements can be found in all genomic regions but they are far more abundant in AT-rich, gene-poor, and low-recombining regions of the genome. In addition, the sex chromosomes and some genes seem disproportionately enriched in L1 elements. Insertion bias and selective processes can both account for this biased distribution of L1 elements. L1 elements do not appear to insert randomly in the genome and this insertion bias can at least partially explain the genomic distribution of L1. The contrasted distribution of L1 and Alu elements suggests that postinsertional processes play a major role in shaping L1 distribution. The most likely mechanism is the loss of recently integrated L1 elements that are deleterious (negative selection) either because of disruption of gene function or their ability to mediate ectopic recombination. By comparison, the retention of L1 elements because of some positive effect is limited to a small fraction of the genome. Understanding the respective importance of insertion bias and selection will require a better knowledge of insertion mechanisms and the dynamics of L1 inserts in populations.

Journal Article↗
PubMed1999

Characterization of potential insertion sites in the core antigen of hepatitis B virus by the use of a short-sized model epitope.

Core particles of hepatitis B virus (HBV) are able to improve the immunogenicity of foreign sequences exposed on the particle surface. The insertion site in the core antigen of HBV (HBcAg) determines the surface presentation and thus the immunogenicity of the foreign sequence. For direct comparison of the value of potential insertion sites in the core antigen, we constructed vectors allowing insertions of a model marker epitope DPAFR. This epitope was inserted at the N-terminus, the c/e1 loop, behind amino acid (aa) 144 and behind aa 183 (DPAF only). In addition, we generated a mosaic construct allowing the co-expression of HBcAg and a HBcAg/DPAFR fusion protein due to a suppressor tRNA-mediated readthrough mechanism. All 6 constructs allowed the formation of chimaeric or mosaic core-like particles. Western blot analyses and a direct ELISA demonstrated the presence of the DPAFR sequence in the chimaeric and mosaic particles. Competitive ELISA and immune electron-microscopic data suggested the c/e1 loop as the insertion site of choice for presenting foreign sequences on the surface of chimaeric HBV core particles. However, the N-terminal fusion also allowed partial surface exposure of the DPAFR motif. In contrast, in particles of constructs carrying the DPAFR insert at aa position 144 or 183, respectively, the epitope seemed not to be surface accessible.

Blotting, Western↗
PubMedDate not supplied

Cutaneous microdialysis in the rat: insertion trauma and effect of anaesthesia studied by laser Doppler perfusion imaging and histamine release.

Microdialysis makes it feasible to study compounds in the extracellular space of cutaneous tissue in vivo. The insertion of the microdialysis probe causes a trauma, which may be anticipated to influence the microdialysis process. The effect of anaesthesia on basal skin blood flow and the trauma in the skin after insertion of a microdialysis probe were investigated. Hairless rats were anaesthetized either with halothane or pentobarbital sodium. Basal skin blood flow and the effect of insertion of a microdialysis probe were measured by laser Doppler perfusion imaging. Trauma-induced histamine release was investigated. Rats anaesthetized with pentobarbital sodium showed a stable skin perfusion in contrast to rats anaesthetized with halothane. A significant increase in blood flow was seen after insertion of the microdialysis probe in the dermis of rats anaesthetized with pentobarbital sodium, while a change in skin blood flow was not observed in rats anaesthetized with halothane. Probe insertion caused histamine release in rats. A minimum equilibration period of 30 min between probe insertion and the start of the experiment is recommended in future studies, allowing immediate events of the trauma to subside and stabilize.

Adjuvants, Anesthesia↗
PubMed2003

Gastrostomy tube insertion into intestinal-cutaneous tract fistulas is a new technique to improve fistula control.

BACKGROUND: The management of gastrointestinal-cutaneous fistulas may be complicated by the difficulty in obtaining adequate control of the fistula tract. This study describes a new method to obtain better fistula control utilizing a semi-rigid stent in the form of a gastrostomy tube. METHODS: Consecutive patients with intestinal-cutaneous fistulas of at least 3 weeks duration and treated by the new technique were analyzed. The technique involved the insertion of a guide wire into the fistula tract from the luminal side using an endoscope, snaring the wire with a Dormia basket inserted into the fistula tract from the cutaneous side and then exteriorized. The gastrostomy tube was then pulled with the guide wire from the lumen along the fistula tract and out through the skin. RESULTS: Five patients had had fistulas for a median duration of 42 (range 26-140) days before insertion of the gastrostomy tube. The gastrostomy tube was replaced with a smaller diameter tube in 4 of the patients (range 1-3 changes). The patients were discharged from the hospital at a median of 14 (range 12-23) days after the tube insertion but with the tube in situ. The median time from the insertion of the tube to its removal was 42 (range 32-108) days. CONCLUSIONS: Gastrostomy tube insertion using minimally invasive techniques may improve fistula control enabling patients to be discharged home sooner than otherwise and improve the rate of healing.

Adult↗
PubMedDate not supplied

Effects of insertion depth of cochlear implant electrodes upon speech perception.

OBJECTIVE: To investigate whether the insertion depth of a cochlear implant array affects postoperative speech perception. DESIGN: The subjects were 48 postlingually deaf adults who received either the Nucleus 22 or the Nucleus 24 cochlear implant with a straight array. A postoperative radiograph of the cochlear electrode was used to estimate insertion depth, as either the angle of the electrode tip (angle) or the intracochlear length of the electrode (length). Other estimates of insertion depth included the numbers of active electrodes and channels used by the speech processor. Electrode depth, together with the duration of deafness, hearing aid usage, pre-operative speech perception score and pre-operative pure-tone averages were independent variables in a forward stepwise multiple regression analysis, where the dependent variables were postoperative CNC words and CNC phonemes. RESULTS: Duration of deafness and insertion depth (angle, insertion length or active electrodes) were the predictive variables for CNC words or CNC phonemes. Angle was the best 'depth-related' predictor of postoperative speech perception. An even clearer relationship was found between CUNY sentences in noise and angle, in a subset of 26 patients. CONCLUSION: Depth of electrode insertion affects postoperative speech perception.

Adult↗
PubMed2005

Extraocular muscle insertions relative to the fovea and optic nerve: humans and rhesus macaque.

PURPOSE: To identify extraocular anatomic relationships of muscle insertions relative to the fovea and the optic nerve. METHODS: Thirty-eight human eye bank eyes and 10 rhesus macaque (Macaca mulatta) eyes were measured. Ten human volunteers were used to determine the horizontal rectus muscle-to-globe apposition in primary, left, and right gaze. RESULTS: External globe measurements (human/rhesus; mm +/- SD) from the temporal border of the optic nerve (ON) to the center of the fovea (F) were 3.7 +/- 0.6 and 2.6 +/- 0.2; F to the posterior border of the inferior oblique (IO) insertion, 2.5 +/- 0.8 and 0.5 +/- 0.4; ON to the posterior border of the IO, 5.6 +/- 0.9 and 2.8 +/- 0.3; horizontal axial plane (H) of the eye, defined by the long posterior ciliary artery, to the IO, 2.0 +/- 0.8 and 0.5 +/- 0.4; and H to F, 1.0 +/- 0.6 and 0.4 +/- 0.3, respectively. The IO insertion formed an arc, inferior to H, with an anterior-to-posterior cord insertion width of 9.2 +/- 0.7 and 7.7 +/- 0.3. The IO angle of insertion (theta) was 30 degrees in 84% (32/38) and 0 degrees in 16% (6/38) of human eyes and 25 to 30 degrees in all rhesus. In 20 human volunteers, from the ON to the apex of lateral rectus globe apposition was 13.9 +/- 1.1 in primary, 17.2 +/- 1.9 in lateral, and 9.3 +/- 1.7 in medial gaze. CONCLUSIONS: The fovea is located mostly superior and slightly posterior to the posterior border of the IO insertion. Topographic relationships of the extraocular muscles relative to the fovea are essential for the design of extraocular drug delivery systems.

Aged↗
PubMed1998

A 6-basepair insert in the reverse transcriptase gene of human immunodeficiency virus type 1 confers resistance to multiple nucleoside inhibitors.

While many point mutations in the HIV-1 reverse transcriptase (RT) confer resistance to antiretroviral drugs, inserts or deletions in this gene have not been previously characterized. In this report, 14 RT inhibitor-treated patients were found to have HIV-1 strains possessing a 6-basepair insert between codons 69 and 70 of the RT gene. Known drug resistance mutations were also observed in these strains, with T215Y appearing in all strains. Genotypic analysis indicated that the inserts had substantial nucleotide variability that resulted in relatively restricted sets of amino acid sequences. Linkage of patients' treatment histories with longitudinal sequencing data showed that insert strains appeared during drug regimens containing ddI or ddC, with prior or concurrent AZT treatment. Drug susceptibility tests of recombinant patient isolates showed reduced susceptibility to nearly all nucleoside RT inhibitors. Site- directed mutagenesis studies confirmed the role of the inserts alone in conferring reduced susceptibility to most RT inhibitors. The addition of AZT-associated drug resistance mutations further increased the range and magnitude of resistance. These results establish that inserts, like point mutations, are selected in vivo during antiretroviral therapy and provide resistance to multiple nucleoside analogs.

Amino Acid Sequence↗
PubMed1989

An in vitro investigation of the effects of glass inserts on the effective composite resin polymerization shrinkage.

We placed an MOD preparation in each of 12 permanent molars, then restored each tooth with a posterior composite resin by means of six different application techniques (I-polymerization as one complete unit; II--polymerization as one complete unit with glass inserts; III--polymerization in gingivo-occlusal increments; IV-polymerization in gingivo-occlusal increments with glass inserts; V--polymerization in bucco-lingual increments; and VI--polymerization in a gingival increment with glass inserts, then bucco-lingual increments). A precision strain gauge was attached to the buccal surface of each tooth and balanced at zero. After each increment was polymerized, the strain appearing on the strain gauge indicator was recorded. Each tooth was restored by use of all techniques; two teeth started with each technique. Results demonstrated the average microstrain units to be 127-I, 102-II, 105-III, 86-IV, 72-V, and 66-VI. A randomized block design was the format used for data evaluation. Scheffé's Test indicated that composite resin placement and polymerization in bucco-lingual increments (V) created significantly less cuspal deflection than polymerization as one complete unit, with or without glass inserts (I and II), p less than 0.001, and gingivo-occlusal increments (III), p less than 0.05. Placement and polymerization in a gingival increment with glass inserts, then bucco-lingual increments (VI), also created significantly less internal deflection than polymerization as one complete unit, with or without glass inserts (I and II), p less than 0.001, and gingivo-occlusal increments (III), p less than 0.005.

Analysis of Variance↗
PubMedDate not supplied

Incidence of arrhythmia with central venous catheter insertion and exchange.

The risk of complication during the insertion or exchange of central venous catheters has been well documented. The majority of complications involve mechanical problems associated with insertion. Although cardiac arrhythmia has been acknowledged as a possible complication, its incidence has never been quantified. We performed cardiac monitoring on patients during 51 central venous catheter insertions or exchanges to determine the incidence of cardiac arrhythmias during guidewire insertion. Forty-one percent of procedures resulted in atrial arrhythmias and 25% produced some degree of ventricular ectopy, 30% of these were ventricular couplets or greater. Ventricular ectopy was significantly more common in shorter patients (160 +/- 8 vs 168 +/- 11 cm, p less than 0.05) and when the catheter was inserted from the right subclavian position (43% ventricular ectopy vs 10% at the other sites). Other variables such as age, cardiac history, serum potassium, type of procedure, and catheter brand were not significant. It is our conclusion that over-insertion of the wire causes this cardiac stimulation. Despite the absence of morbidity or mortality in this study, this incidence of ventricular ectopy indicates that there is a distinct possibility of a malignant arrhythmia being precipitated by a guidewire. Some modification of the current protocol for these procedures seems indicated.

Arrhythmias, Cardiac↗
PubMed1992

Propofol induction for laryngeal mask airway insertion: dose requirement and cardiorespiratory effects.

The dosage, haemodynamic and respiratory effects of propofol for laryngeal mask airway (LMA) insertion were investigated. Fifty patients (ASA I-II) were randomly assigned one of four induction doses of propofol (1.5-2.5 mg/kg) delivered over 30 seconds and the first attempt at LMA insertion was made at 90 seconds. The LMA was inserted at 90 seconds in 35 patients and by 300 seconds in 13 others (mean plasma concentration at 90 seconds was 7.7 mcg/ml (no delay) versus 5.2 mcg/ml (insertion delayed), P < 0.01). Insertion was less successful after 1.5 mcg/kg (failed at 90 seconds in 6 of 12 patients), but did not vary with the other doses. Additional propofol (0.5 mg/kg/30s) was required in 22 patients for LMA insertion or to prevent movement, resulting in propofol concentrations at 120-180 seconds above 7 mcg/ml. Respiratory effects were minor, but MAP decreased by 18 +/- 1.4 mmHg at 90 seconds. Cardiovascular effects did not differ significantly between dosage groups or with the use of additional propofol.

Adult↗
PubMedDate not supplied

The effect of screw insertion torque on tendons fixed with spiked washers.

The long-term success of a hamstring tendon graft depends not only on the type of device that is used for fixation but also on the mechanical interlocking of the soft tissue between the fixation device and bone. The purpose of this study was to evaluate the effect of screw insertion torque on the structural properties of soft tissue fixed to bone with a spiked metal washer. Two bovine tendons, one similar in size to a human semitendinosus tendon and the other similar in size to a human gracilis tendon, were secured to a bovine femur using a figure-of-8 technique with screws and metal spiked washers. A single load to failure was applied at 25 mm/sec. A significant positive linear correlation was observed between fixation screw insertion torque magnitude and the ultimate failure load value. An increase in the fixation screw insertion torque produced an increase in the ultimate failure load value. Similarly, there was a significant positive linear correlation between fixation screw insertion torque magnitude and the average maximum linear load value. No relationship was detected between screw insertion torque magnitude and the linear stiffness values of the tendon-fixation construct, indicating that a reproducible model was used. This study demonstrates that screw insertion torque is an important variable that controls the initial strength of soft tissue fixation to bone.

Animals↗
PubMedDate not supplied

The anterior horn of the medical meniscus. An anatomic study of its insertion.

A morphologic study of 48 cadaveric knees was performed to more accurately define the osseous and soft tissue anatomy of the insertion of the anterior horn of the medial meniscus. Soft tissue relationships of the anterior horn of the medial meniscus to the anterior cruciate ligament and the lateral meniscus were examined. Four tibial insertion locations of the medial meniscus were identifiable by bony landmarks. Type I insertions were located in the flat intercondylar region of the tibial plateau; type II occurred on the downward slope from the medial articular plateau to the intercondylar region; type III occurred on the anterior slope of the tibial plateau; there was no firm bony insertion of the anterior horn in type IV. The occurrence for type I was 59% (20 of 34); type II, 24% (8 of 34); type III, 15% (5 of 34); and type IV, 3% (1 of 34). The variance in insertion patterns may have clinical applications for patients with atypical anterior knee pain and for performing meniscal allograft. Type III and type IV insertions may be unable to resist peripheral extrusion of the loaded meniscus, placing it at risk for anterior subluxation and causing anterior knee pain in specific cases. Awareness of these patterns may be valuable in medial meniscus harvest and transplantation.

Aged↗
PubMed2005

Influence of heel height and shoe insert on comfort perception and biomechanical performance of young female adults during walking.

BACKGROUND: The possible negative effects of high-heeled shoes on subjective comfort perception and objective biomechanical assessment have been noted. Although shoe inserts have been widely applied in footwear to increase comfort and to reduce the frequency of movement-related injury, no study has attempted to identify insert effectiveness in high heels. The purpose of this study was to determine the effects of heel height and shoe inserts on comfort and biomechanics as represented by plantar pressure and ground reaction force (GRF). METHODS: Twenty young female adults performed the test conditions formed by the cross-matching of shoe inserts (shoe without insert and shoe with total contact insert [TCI]) and heel height (a flat, a low heel [3.8 cm] and a high heel [7.6 cm]). Two-way analyses of variance for repeated measures design were used to test condition effects on comfort rating, plantar pressure, and GRF during gait. To determine the biomechanical variables that can predict comfort, a multiple linear regression with stepwise method was done. RESULTS: The results showed that discomfort increased with heel height. In high heels, the plantar pressure in the heel and midfoot shifted to the medial forefoot, and the vertical and anteroposterior GRF increased. Use of the TCI reduced the peak pressure in the medial forefoot. Interestingly, the effectiveness of the TCI was greater in the higher heels than in the lower heels and in flat heels. The peak pressure in the medial forefoot, impact force, and the first peak vertical GRF could explain 75.6% of the variance of comfort in high-heeled gait. CONCLUSIONS: These findings suggest that higher heels result in decreased comfort, which can be reflected by both the subjective rating scale and biomechanical variables. Use of a TCI altered the biomechanics and therefore improved the comfort in high-heeled shoes.

Adult↗
PubMed1999

Risk of avulsion of the Achilles tendon after partial excision for treatment of insertional tendonitis and Haglund's deformity: a biomechanical study.

Surgical treatment of posterior heel pain caused by insertional (calcific) Achilles tendonitis or retrocalcaneal bursitis includes resection of diseased tendon or exostectomy. Currently, no guidelines exist to determine how much tendon may be excised without risking rupture of the Achilles tendon. Anatomic dissections revealed the average height of the insertion measured 19.8 mm (range, 13-25 mm). Average width at the proximal aspect of the insertion measured 23.8 mm (range, 17-30 mm) and distally measured 31.2 (range, 25-38 mm). To assess the risk of avulsion, the tendon insertion was partially released in 25% increments of its measured height or width by one of the four methods: (1) from superior to inferior, (2) from the central portion outward, (3) from medial to lateral, and (4) from lateral to medial. Repeated cyclic loading of body weight x 3 was applied, and, if the tendon remained intact, the next 25% increment was released. This process was repeated until failure occurred. Failure occurred in all specimens by an oblique intratendonous separation or shear between the intact portion remaining on the calcaneus and the resected fibers remaining in the clamp. Fibers inserting into the bone did not avulse. Superior-to-inferior resection was found to be superior to the other three methods with eight of nine specimens remaining intact after 75% resection. We therefore conclude that superior-to-inferior offers the greatest margin of safety when performing partial resections of the Achilles insertion, and as much as 50% of the tendon may be resected safely.

Achilles Tendon↗
PubMed2006

Complete association between a retroviral insertion in the tyrosinase gene and the recessive white mutation in chickens.

BACKGROUND: In chickens, three mutant alleles have been reported at the C locus, including the albino mutation, and the recessive white mutation, which is characterized by white plumage and pigmented eyes. The albino mutation was found to be a 6 bp deletion in the tyrosinase (TYR) gene. The present work describes an approach to identify the structural rearrangement in the TYR gene associated with the recessive white mutation. RESULTS: Molecular analysis of the chicken TYR gene has revealed a major structural difference (Restriction Fragment Length Polymorphism, RFLP) in the genomic DNA of the recessive white chicken. A major size difference of 7.7 kb was found in intron 4 of the TYR gene by long-range PCR. Molecular cloning and sequencing results showed the insertion of a complete avian retroviral sequence of the Avian Leukosis Virus (ALV) family. Several aberrant transcripts of the tyrosinase gene were found in 10 week old recessive white chickens but not in the homozygous wild type colored chicken. We established a rapid genotyping diagnostic test based on the discovery of this retroviral insertion. It shows that all homozygous carriers of this insertion had a white plumage in various chicken strains. Furthermore, it was possible to distinguish heterozygous carriers from homozygous normal chickens in a segregating line. CONCLUSION: In this study, we conclude that the insertion of a complete avian retroviral sequence in intron 4 of the tyrosinase gene is diagnostic of the recessive white mutation in chickens. This insertion causes aberrant transcripts lacking exon 5, and we propose that this insertion is the causal mutation for the recessive white allele in the chicken.

Animals↗
PubMed2004

Rapid identification and mapping of insertion sequences in Escherichia coli genomes using vectorette PCR.

BACKGROUND: Insertion sequences (IS) are small DNA segments capable of transposing within and between prokaryotic genomes, often causing insertional mutations and chromosomal rearrangements. Although several methods are available for locating ISs in microbial genomes, they are either labor-intensive or inefficient. Here, we use vectorette PCR to identify and map the genomic positions of the eight insertion sequences (IS1, 2, 3, 4, 5, 30, 150, and 186) found in E. coli strain CGSC6300, a close relative of MG1655 whose genome has been sequenced. RESULTS: Genomic DNA from strain CGSC6300 was digested with a four-base cutter Rsa I and the resulting restriction fragments ligated onto vectorette units. Using IS-specific primers directed outward from the extreme ends of each IS and a vectorette primer, flanking DNA fragments were amplified from all but one of the 37 IS elements identified in the genomic sequence of MG1655. Purification and sequencing of the PCR products confirmed that they are IS-associated flanking DNA fragments corresponding to the known IS locations in the MG1655 genome. Seven additional insertions were found in strain CGSC6300 indicating that very closely related isolates of the same laboratory strain (the K12 isolate) may differ in their IS complement. Two other E. coli K12 derivatives, TD2 and TD10, were also analyzed by vectorette PCR. They share 36 of the MG1655 IS sites as well as having 16 and 18 additional insertions, respectively. CONCLUSION: This study shows that vectorette PCR is a swift, efficient, reliable method for typing microbial strains and identifying and mapping IS insertion sites present in microbial genomes. Unlike Southern hybridization and inverse PCR, our approach involves only one genomic digest and one ligation step. Vectorette PCR is then used to simultaneously amplify all IS elements of a given type, making it a rapid and sensitive means to survey IS elements in genomes. The ability to rapidly identify the IS complements of microbial genomes should facilitate subtyping closely related pathogens during disease outbreaks.

Bacterial Typing Techniques↗