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PubMed1992

Nonrandom orientation of transposon Tn5supF insertions in phage lambda.

Transposition of mini-transposon Tn5supF to phage lambda can be selected in two ways: (i) by plaque formation on a dnaB amber strain of Escherichia coli, which requires expression of the transposon-borne suppressor tRNA gene (supF) during lytic phage growth, or (ii) by lysogenization of a strain with amber mutations in tet and amp resistance genes, and selection of TcR ApR (Sup+) transductant colonies. Tn5supF insertions in several lambda clones were isolated and mapped using a polymerase chain reaction (PCR) amplification method. Among insertions selected during lytic growth, more than 90% were oriented such that supF could be transcribed from an upstream lambda promoter. In contrast, half of those selected by transduction were in each orientation. These results indicate that Tn5supF insertion occurs with equal frequency in each orientation. However, Tn5supF insertion phages in which transcription from the lambda and supF promoters would collide tend to be lost when supF is selected during lytic growth. The tendency to recover Tn5supF insertions in only one orientation is useful in a transposon- and crossover-PCR-based method for preparing templates for DNA sequencing.

Bacterial Proteins↗

PubMed1992

Patellofemoral relationships and distal insertion of the vastus medialis muscle: a magnetic resonance imaging study in nonsymptomatic subjects and in patients with patellar dislocation.

The correlation between the insertion level of the vastus medialis muscle and lateral patellofemoral angle (LPA), lateral patellar displacement (LPD) and tilt (LPT), and the height of the patella (LT/LP) was analyzed by magnetic resonance imaging (MRI) in patients with patellar dislocation (n = 10) and in control subjects (n = 10). Images were produced in 0 degrees and 20 degrees of knee flexion. The insertion level to the patella was also analyzed with the knee in extension. No significant correlation was noted between the insertion level and different patellofemoral indexes, but multiple-regression analysis showed that the best predictor for the insertion level was the LPA with the knee in extension. The insertion level was significantly more proximal in patients with patellar dislocations than in normal subjects.

Adolescent↗

PubMed1991

Close linkage of a transgene insertion site to the steel (Sl) locus on mouse chromosome 10.

The characterization of the insertion sites of exogenous sequences in transgenic mice can identify loci that are potentially useful for the genetic analysis of the mammalian genome. We have found that the transgene insertion site in the transgenic line TG.EB is tightly linked with the Steel (Sl) locus on mouse chromosome 10. In a backcross between doubly heterozygous transgenic Sl (Tg.EB +/+ Sl) mice and wild-type mice, only one recombinant was found in 135 progeny (recombination percentage = 0.7 +/- 0.7). The recombination frequency of the transgene with marker loci known to flank Sl was consistent with a map position close to Sl. Genomic sequences that are adjacent to the transgene insertion site were cloned and found to be tightly linked with the Sl locus in interspecific crosses using nontransgenic mice. Recombination analysis utilizing the transgene insertion site locus was used to show that a recently identified hematopoietic growth factor is encoded at Sl. The cloned sequences from the transgene insertion site are polymorphic in inbred strains of mice and can be utilized to determine the genotype at Sl during early embryonic development. Further, they may be useful in characterizing the genomic region near Sl that is affected in Sl deletion mutants.

Animals↗

PubMed1994

Rapid isolation of cosmid insert DNA by triple-helix-mediated affinity capture.

A simple and rapid method for the isolation of cosmid insert DNA was developed based on triple-helix-mediated affinity capture (TAC). A modified cosmid was constructed from the SuperCos 1 cosmid vector by flanking the cloning site with two homopurine-homopyrimidine triple-helix-forming sequences. The cosmid DNA is digested with NotI restriction enzyme to release the insert DNA. The NotI-digested cosmid DNA is then combined with a biotinylated homopyrimidine oligonucleotide in an acidic buffer solution to form a triple-helix complex. The triple-helix complex is captured with streptavidin-coated magnetic beads. Insert DNA is eluted by adding a pH 9 buffered solution to the captured complex. The purified insert DNA is recovered with a yield of up to 95% and a purity of at least 95%. The isolated insert DNA was directly digested with CviJI restriction endonuclease to generate random fragments for shotgun sequencing.

Base Sequence↗

PubMed2006

Violation of pure insertion during mental rotation is independent of stimulus type, task, and subjects' age.

The experiment validated and extended the finding of Ilan and Miller (1994) [A violation of pure insertion: mental rotation and choice reaction time. Journal of Experimental Psychology: Human Perception and Psychophysics 20, 520-536] that the mental rotation process is not purely inserted into a mirror-normal discrimination task. In contrast to their work we used other experimental stimuli (drawings of animals instead of characters), a different task (same/different comparison) and investigated this effect under a developmental perspective. Adults and children between the age of 8 and 10 took significantly longer to respond to upright drawings of animals in conditions containing rotated stimuli than in conditions containing only upright stimuli, indicating a violation of pure insertion. In general, we found evidence that the violation of pure insertion during a mental rotation task itself can be generalised across stimulus type, task, and subject populations. However, for children this effect was independent of the format of the stimuli, while for adults the effect was larger for mirror-imaged than for identical objects. This suggests that the violation of pure insertion might occur at different processing stages as a function of age.

Adult↗

PubMed2003

A randomized controlled trial evaluating the efficacy of tetracaine gel for pain relief from peripherally inserted central catheters in infants.

BACKGROUND: Insertion of peripherally inserted central catheters (PICC) is a commonly performed procedure in both preterm and term infants. Tetracaine 4% gel (Ametop; Smith & Nephew Inc, St. Laurent, Quebec), a topical anesthetic, although reported to be effective for reducing the pain of venipuncture in neonates, has not been investigated for the management of pain associated with the PICC procedure. PURPOSE: To determine the efficacy of tetracaine gel for managing the pain associated with the PICC procedure in preterm and term infants. METHODS: A double-blind, placebo-controlled, randomized controlled trial (RCT) design was used. Infants undergoing nonurgent PICC insertion were randomized to receive either the treatment (1.0 g of tetracaine 4% gel) or placebo control (1.0 g of eucerin-plus cream) applied to the skin under occlusion for 30 minutes before the procedure. Data on the behavioral (facial expression) and physiologic (heart rate and oxygen saturation) indicators of pain were collected via videotaping and computer monitoring throughout the procedure. Data then were coded and measured by independent observers using the Premature Infant Pain Profile (PIPP; Stevens et al, 1996), and analyzed using descriptive statistics and repeated-measures analyses of variance. RESULTS: Forty-nine infants, gestational age 27 to 41 weeks (mean = 33; SD = 4.2) and age at time of insertion 2 to 85 days (mean = 18; SD = 22.5) participated. No differences were found between the groups at the time of randomization. There were no adverse cardiorespiratory events or local skin reactions in either group. There was a significant within-subjects main effect of time across the procedure (F[48,3] = 11.03; P < 0.0001). There was no significant between-subjects main effect of group (F[48,1] = 0.11; P = 0.74) and no (group x time) interaction (F[48,3] = 0.45; P = 0.72). CONCLUSION: Tetracaine gel was not effective for pain relief for PICC insertion in infants. Its use for pain relief cannot be recommended based on the results of this study. Other pharmacologic, behavioral, and physical interventions should be investigated for safety and relief of procedural pain in this population of infants.

Anesthetics, Local↗

PubMed2006

Pain from copper intrauterine device insertion: randomized trial of prophylactic ibuprofen.

OBJECTIVES: This study was undertaken to determine whether 400 mg of prophylactic ibuprofen can alleviate pain from insertion of an intrauterine device (IUD) and to measure level of pain with improved techniques. STUDY DESIGN: We conducted a randomized, double-blind, placebo-controlled trial of 2019 first-time IUD users: 1008 women received placebo and 1011 women received 400 mg of ibuprofen. Participants took the single tablet at least 45 minutes before IUD insertion. Immediately after insertion, participants recorded level of pain by using a 10-cm visual analog scale, with the value of 10 meaning "worst imaginable pain." RESULTS: Median level of pain was 1.0 for both ibuprofen and placebo participants; rank test statistics confirmed no difference. Some subgroups of women experienced higher pain (eg, nulliparous women), but ibuprofen still had no important impact on level of pain. CONCLUSION: Even among first-time users, pain from IUD insertion is generally low. Prophylactic ibuprofen as used in this protocol does not reduce IUD insertion pain.

Adult↗

PubMed2005

The acetabular insert-metal backing interface: an additional source of polyethylene wear debris.

In cementless acetabular arthroplasty, the interface between the metal backing and the ultra-high-molecular-weight polyethylene acetabular insert surface is a potential source of polyethylene debris. This study of 55 early-generation acetabular inserts found that severe wear of the convex insert surface correlates with osteolysis. Wear of the concave insert surface did not correlate strongly with osteolysis probably owing to prevalent micromotion and wear at the convex surface interface. Although concern over linear wear predominates with contemporary designs, if initial liner engagement is compromised or locking mechanism failure occurs with time, the convex insert surface again may become a significant source of debris contributing to osteolysis.

Acetabulum↗

PubMed2004

Insertion torque pullout strength relationship of soft tissue tendon graft tibia tunnel fixation with a bioabsorbable interference screw.

PURPOSE: The purpose of this study was to evaluate the relationship between insertion torque and the biomechanical characteristics of soft tissue tendon graft tibia fixation with a bioabsorbable interference screw. TYPE OF STUDY: Biomechanical study. METHODS: Doubled tibialis anterior allografts (n = 20, length = 100 mm, diameter = 9 mm) prepared for anterior cruciate ligament (ACL) reconstructions were divided into 3 groups. Maximum insertion torque was measured as grafts were fixed by the same surgeon with a 10-mm diameter, 35-mm long screw in a 7-mm diameter tunnel (dilated to 9 mm) created in either 0.16 or 0.32 g/cm3 dense synthetic bone or cadaveric tibiae (0.84 +/- 0.15 g/cm2). Tensile testing to construct failure was then performed. RESULTS: All constructs failed by tunnel pullout. Higher density synthetic bone had greater load at failure than lower density synthetic bone (486.6 +/- 83.8 v 271.6 +/- 52.6 N, P <.0001) and a slightly greater proportion of variance could be explained in synthetic bone (R2 = 0.74, P <.0001) than in cadaveric tibiae (R2 = 0.64, P =.017). Higher density synthetic bone displayed greater stiffness than lower density synthetic bone (68.1 +/- 21.6 v 37.7 +/- 11.2 N/mm, P =.012) and a higher proportion of variance could be explained in cadaveric tibiae (R2 = 0.72, P =.008) than in synthetic bone (R2 = 0.48, P =.012). Greater insertion torque levels were seen in higher density synthetic bone (2.97 +/- 0.35 v 1.24 +/- 0.06 Nm, P <.0001) than in lower density synthetic bone, and a higher proportion of variance could be explained in synthetic bone (R2 = 0.94, P <.0001) than in cadaveric tibiae (R2 = 0.74, P =.006). CONCLUSIONS: Strong relationships were evident between insertion torque, bone mineral density (BMD) and load to failure across constructs. Differences between the synthetic bone groups and cadaveric tibiae, however, suggest the influence of mixed cortical and cancellous bone, nonuniform structural patterning, and differing BMD levels and distributions in the cadaveric tibiae. CLINICAL RELEVANCE: Soft tissue graft tibial tunnel fixation is directly related to insertion torque and BMD. Synthetic models with mixed bone characteristics are needed to more accurately depict human tibiae during fixation testing.

Absorbable Implants↗

PubMed2004

The role of lipids in membrane insertion and translocation of bacterial proteins.

Phospholipids are essential building blocks of membranes and maintain the membrane permeability barrier of cells and organelles. They provide not only the bilayer matrix in which the functional membrane proteins reside, but they also can play direct roles in many essential cellular processes. In this review, we give an overview of the lipid involvement in protein translocation across and insertion into the Escherichia coli inner membrane. We describe the key and general roles that lipids play in these processes in conjunction with the protein components involved. We focus on the Sec-mediated insertion of leader peptidase. We describe as well the more direct roles that lipids play in insertion of the small coat proteins Pf3 and M13. Finally, we focus on the role of lipids in membrane assembly of oligomeric membrane proteins, using the potassium channel KcsA as model protein. In all cases, the anionic lipids and lipids with small headgroups play important roles in either determining the efficiency of the insertion and assembly process or contributing to the directionality of the insertion process.

Cell Membrane↗

PubMed2004

Does VDAC insert into membranes in random orientation?

It is widely accepted that voltage-dependent anion-selective channel (VDAC) inserts into planar lipid bilayers in a random orientation. This is in contrast to the well-documented oriented insertion of various channel-forming proteins. Because of the potential importance of this issue, we have examined the orientation of VDAC inserted in membranes. The time constants of the VDAC-current relaxation in response to applied positive and negative voltage pulses were used to characterize the channel orientation. We have found that VDAC channels can be separated into two groups according to differences in the time constant ratio. The difference in time constant ratio between the two main groups of VDAC channels was quantitative, and not qualitative as would be expected for opposite topologies. This finding allows us to hypothesize that both groups of VDAC channels possess a qualitatively similar asymmetry with respect to the localization of voltage-gated domains and, consequently, with respect to its entire molecular structure. The probability of having each type of VDAC channel conformation is predetermined by the protein structure in aqueous solution. A striking resemblance between asymmetry in voltage sensitivity at the single-channel and multi-channel levels was also demonstrated. The first inserted channel seems to direct subsequent insertions of channels with a similar conformation.

Calcium↗

PubMed2005

CT-guided multi-catheter insertion technique for partial breast brachytherapy: reliable target coverage and dose homogeneity.

PURPOSE: To evaluate the feasibility and dosimetric reliability of a CT-guided method of catheter insertion for accelerated partial breast brachytherapy (APBB). MATERIALS AND METHODS: From 1995 to 2002, 77 patients were treated with APBB using a multi-catheter low-dose-rate or high-dose-rate approach. Within that timeframe, 29 patients with early stage invasive breast cancer were treated with high-dose-rate partial breast brachytherapy and had CT scans of the brachytherapy implant available for analysis. Initially, catheter insertion was accomplished in the operating room at the time of lumpectomy using standard free-hand insertion techniques under fluoroscopic guidance and subsequent orthogonal film dosimetry. To improve the efficiency and quality of the technique, the procedure was moved to the departmental CT-simulation suite where the catheters were placed with CT guidance. Basic guidelines of needle insertion and implant construction were followed to assure appropriate intercatheter and interplanar spacing that allowed optimal dosimetric coverage of the target volume. Target volumes were delineated and a treatment plan generated using a 3D planning system (Varian Brachyvision). PTV 1 cm was defined as the lumpectomy cavity plus 1 cm and PTV 2 cm as the lumpectomy cavity plus 2 cm. Target coverage goals were set as delivery of 100% of the prescribed dose to >95% of PTV 1 cm and >90% of the dose to >90% of PTV 2 cm. Dose homogeneity index (DHI) was defined as (V150%-V100%/V100%) with a goal of achieving >0.75. Fifteen patients were treated using the initial method and 14 patients using the CT-guided technique. Targets were retrospectively entered in the initial group and dose volume histogram analysis completed on all patients. The ability of each technique to achieve the target coverage and homogeneity goals was compared. RESULTS: With the change from traditional techniques to a CT-guided technique, the percentage of patients satisfying all dosimetric goals increased from 42% to 93%. Mean dose coverage (defined as the percentage of PTV 2 cm receiving 90% of the prescribed dose) increased from 89% to 95% (p=0.007) and the mean DHI increased from 0.77 to 0.82 with the new technique (p < 0.005). CONCLUSIONS: Reproducible target coverage and dose homogeneity were achieved with CT-guided catheter insertion and 3D planning software. Catheters can be optimally placed with intraoperative CT evaluation and 3D planning software allows improved implant visualization resulting in optimized dosimetry. Improvements in target coverage and DHI may translate into optimized local control and improved cosmesis with a corresponding reduction in the risk of complications.

Aged↗

PubMed2004

Norplant insertions at the Zeynep Kamil Gynecologic and Pediatric Training Research Hospital in Istanbul.

OBJECTIVE: This study was conducted to determine sociodemographic characteristics and usage interval according to insertion period, observed side effects and reasons for discontinuation in 756 cases where Norplant was inserted and removed for any reasons at our hospital since 1994. METHODS: Seven-hundred and fifty-six cases in whom Norplant was inserted and removed since 1994 were included in our study. Sociodemographic characteristics, former contraception method, reasons for choosing this method and side effects seen during the usage period were determined. In all cases, reasons for discontinuation, sociodemographic characteristics and usage interval according to the insertion period were investigated. Statistical analysis of this study was performed with SPSS 9.0 (analysis of variance). RESULTS: Mean age of cases was 26.5 +/- 4.9 years, mean number of living children was 2.0 +/- 1.2, and 50.4% of cases had no health insurance. Most of the cases used coitus interruptus previously as a contraceptive method and chose Norplant use because of its effectiveness. Insertion periods were as follows: interval, n = 513 (67.9%); postpartum, n = 127 (16.8%) and postabortion, n = 116 (15.3%). Various side effects were detected in 79.8% of the cases. Bleeding problems were seen in 69.8%. Pregnancy occurred in only one case. Mean Norplant usage interval was 3.08 +/- 1.68 years. The longer usage interval was seen in cases with lower educational level. When we compared the usage intervals between interval, postpartum and postabortion periods, we found that the interval group had a shorter mean duration of Norplant use. Discontinuation because of bleeding problems occurred in 38.1%. Removal of all Norplant implants was performed at a single session in 731 cases (96.4%). After Norplant removal, most cases selected either condom or IUD as the contraceptive method. CONCLUSION: It is concluded that despite the frequent occurrence of side effects, Norplant is a modern, long-acting, highly effective, reversible, easy-to-use, satisfactory form of birth control, especially in selected cases.

Adult↗

PubMed2005

Does insertion and use of an intrauterine device increase the risk of pelvic inflammatory disease among women with sexually transmitted infection? A systematic review.

Concerns exist as to whether the insertion of copper and levonorgestrel-releasing intrauterine devices (IUDs) increases the risk of pelvic inflammatory disease (PID) among women with sexually transmitted infection (STI). We searched the MEDLINE database for all articles published between January 1966 and March 2005 that included evidence relevant to IUDs and STIs and PID. None of the studies that examined women with STIs compared the risk of PID between those with insertion or use of an IUD and those who had not received an IUD. We reviewed indirect evidence from six prospective studies that examined women with insertion of a copper IUD and compared risk of PID between those with STIs at the time of insertion with those with no STIs. These studies suggested that women with chlamydial infection or gonorrhea at the time of IUD insertion were at an increased risk of PID relative to women without infection. The absolute risk of PID was low for both groups (0-5% for those with STIs and 0-2% for those without).

Female↗

PubMed2005

Insertional Achilles tendinopathy.

There has been significant progress in our understanding of Achilles insertional tendinopathy since Clain and Baxter divided Achilles tendon disorders into noninsertional and insertional tendinopathy in 1992. In this article we specifically concentrate on Achilles insertional tendinopathy. Classically, overuse and poor training habits are considered to be the main etiology of Achilles insertional tendinopathy. This article discusses Achilles insertional tendinopathy from the anatomy of to its management.

Achilles Tendon↗

PubMed2005

A temporal bone study of insertion trauma and intracochlear position of cochlear implant electrodes. I: Comparison of Nucleus banded and Nucleus Contour electrodes.

In recent years, new designs of cochlear implant electrodes have been introduced in an attempt to improve efficiency and performance by locating stimulation sites closer to spiral ganglion neurons and deeper into the scala tympani. The goal of this study was to document insertion depth, intracochlear position and insertion trauma with the Nucleus Contour electrode and to compare results to those observed with the earlier generation Nucleus banded electrode. For this comparison eight Nuclears banded electrodes and 18 Contour electrodes were implanted in cadaver temporal bones using a realistic surgical exposure. Two experienced cochlear implant surgeons and two otology fellows with specialized training in cochlear implant surgery were selected for the study to represent a range of surgical experience similar to that of surgeons currently performing the procedure throughout the world. Following insertion of the electrodes, specimens were imaged using plain film X-ray, embedded in acrylic resin, cut in radial sections with the electrodes in place, and each cut surface was polished. Insertion depth was measured in digitized X-ray images, and trauma was assessed in each cross-section. The Contour electrode inserted more deeply (mean depth=17.9 mm or 417 degrees ) than the banded electrode (mean depth=15.3 mm or 285 degrees ). The incidence and severity of trauma varied substantially among the temporal bones studied. However, the nature and frequency of injuries observed with the two devices were very similar. The Contour electrode was clearly positioned closer to the modiolus than the banded model, and also appeared easier to use. Based on this difference in position and data from previous studies we conclude that the Contour electrode may provide lower thresholds and improved channel selectivity, but the incidence of trauma remains a problem with the newer design. The relative influences of electrode positioning and neural degeneration that may result from trauma are as yet unclear.

Cadaver↗

PubMed2005

Collagen fiber orientation at the tendon to bone insertion and its influence on stress concentrations.

The tendon to bone insertion serves the mechanical role of transferring loads from a relatively compliant tendon to a relatively rigid bone. The details of the mechanism of load transfer are of great importance, since current surgical procedures for tendon reattachment have high failure rates. We hypothesized that the microscopic structure of the insertion is optimized to minimize stress concentrations associated with this load transfer. To explore this, collagen fiber orientation distributions were measured in the supraspinatus tendons of rats. The angular deviation of fibers was fairly uniform across the insertion, and the mean angles of the local distributions deviated mildly from the tendon axis. To explore how these observed property distributions could influence load transfer, these distributions were used to derive material properties for an idealized two-dimensional mechanical model of an insertion. Comparison between stress concentrations in this idealized model and those in three comparison models suggests that the microstructure serves to (1) simultaneously reduce stress concentrations and material mass, and (2) shield the insertion's outward splay from the highest stresses.

Animals↗

PubMed2004

Combined ICRS insertion and LASIK to maximize postoperative residual bed thickness in high myopia.

PURPOSE: To describe a new technique and early outcomes of combined intrastromal corneal ring segment (ICRS) insertion and laser in situ keratomileusis (LASIK) to treat patients with moderate to high myopia and thin corneas. SETTING: University-based academic practice, Boston, Massachusetts, USA. METHODS: Combined ICRS insertion and LASIK was performed in 2 stages: ICRS channel formation (stage I) followed by LASIK and ICRS insertion (stage II). RESULTS: Fifteen eyes of 11 patients with a mean preoperative spherical equivalent of -9.98 diopters (D) +/- 2.60 (SD) (range -7.13 to -16.25 D) and mean preoperative astigmatism of 1.11 +/- 0.75 D (range 0.00 to -3.00 D) were treated with combined ICRS insertion and LASIK. The mean central pachymetry was 526.13 +/- 35.69 microm (472 to 579 microm). The uncorrected visual acuity was 20/40 or better in 7 of 15 eyes (46.67%) at 1 month, 6 of 12 eyes (50.00%) at 3 months, 5 of 12 eyes (41.67%) at 6 months, and 6 of 12 eyes (50.00%) at 12 months. The best spectacle-corrected visual acuity was 20/40 or better at all times. Postoperative maps confirmed the absence of ectasia. The postoperative spherical equivalent was within +/-1.00 D of the intended refraction in 11 of 15 eyes (73.33%) at 1 month, 9 of 12 eyes at 3 and 6 months, and 8 of 12 eyes (66.67%) at 12 months. CONCLUSIONS: Results of combined ICRS insertion and LASIK in moderately to highly myopic patients with relatively thin corneas were good. Long-term studies are needed to determine whether this procedure will decrease the risk of LASIK-induced keratectasia in these patients.

Adult↗