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PubMedDate not supplied

Cumulative experience with 1,273 peripherally inserted central catheters at a single institution.

PURPOSE: To compare bedside insertion of peripherally inserted central catheters (PICCs) by specially-trained nurses with insertion by cardiovascular and interventional radiologists. MATERIALS AND METHODS: Nurses performed 327 bedside insertions with a palpatory, through-the-needle technique in 301 patients. Radiologists performed 542 insertions with a venographic-fluoroscopic direct puncture and sheath technique in 354 patients. RESULTS: A total of 869 PICCs were inserted in 655 patients. Compared with the first interval of the study (reported previously), bedside technical success improved from 74% to 82.6%, technical success decreased from 98.6% to 98.2%, and the service interval for a given PICC decreased from 72.7 to 28.1 days (because PICCs were used instead of peripheral intravenous lines). Rates of thrombophlebitis and infection remained low. Device failure continued to be a problem. About 25% of patients needed insertion of more than one PICC to complete therapy. CONCLUSION: Bedside insertion by specially trained nurses is less costly than insertion by radiologists, but radiologists are needed for difficult initial insertions, PICC salvage, and PICC exchange.

Catheterization↗
PubMed2005

Is the landmark technique safe for the insertion of subclavian venous lines?

BACKGROUND: The complications of central venous line insertion have been highlighted by the recent NICE report advising that ultrasound guidance should be used for central line insertion. METHODS: We report a prospective audit of the complications of subclavian vein central venous line insertion for parenteral nutrition over a five-year period when ultrasound guidance was not used. RESULTS: In total, 201 lines were inserted for parenteral nutrition into a subclavian vein. A single consultant surgeon inserted 120 of the lines and year five or six surgical registrars performed the other line insertions. Five pneumothoraces occurred in four patients who had subclavian lines inserted and a chest drain was required in three cases. Four line tips were found to be going upwards rather than into the superior vena cava. Misplacement was more common with right subclavian insertion. Inability to site the line at that attempt was associated with previous line insertion in four of six patients. CONCLUSION: A low complication rate can be achieved for central line insertion for parenteral nutrition. It is likely that this is due to the small number of experienced operators.

Catheterization, Central Venous↗
PubMed2005

Evidence for Watson-Crick and not Hoogsteen or wobble base pairing in the selection of nucleotides for insertion opposite pyrimidines and a thymine dimer by yeast DNA pol eta.

We have recently reported that pyrene nucleotide is preferentially inserted opposite an abasic site, the 3'-T of a thymine dimer, and most undamaged bases by yeast DNA polymerase eta (pol eta). Because pyrene is a nonpolar molecule with no H-bonding ability, the unusually high efficiencies of dPMP insertion are ascribed to its superior base stacking ability, and underscore the importance of base stacking in the selection of nucleotides by pol eta. To investigate the role of H-bonding and base pair geometry in the selection of nucleotides by pol eta, we determined the insertion efficiencies of the base-modified nucleotides 2,6-diaminopurine, 2-aminopurine, 6-chloropurine, and inosine which would make a different number of H-bonds with the template base depending on base pair geometry. Watson-Crick base pairing appears to play an important role in the selection of nucleotide analogues for insertion opposite C and T as evidenced by the decrease in the relative insertion efficiencies with a decrease in the number of Watson-Crick H-bonds and an increase in the number of donor-donor and acceptor-acceptor interactions. The selectivity of nucleotide insertion is greater opposite the 5'-T than the 3'-T of the thymine dimer, in accord with previous work suggesting that the 5'-T is held more rigidly than the 3'-T. Furthermore, insertion of A opposite both Ts of the dimer appears to be mediated by Watson-Crick base pairing and not by Hoogsteen base pairing based on the almost identical insertion efficiencies of A and 7-deaza-A, the latter of which lacks H-bonding capability at N7. The relative efficiencies for insertion of nucleotides that can form Watson-Crick base pairs parallel those for the Klenow fragment, whereas the Klenow fragment more strongly discriminates against mismatches, in accord with its greater shape selectivity. These results underscore the importance of H-bonding and Watson-Crick base pair geometry in the selection of nucleotides by both pol eta and the Klenow fragment, and the lesser role of shape selection in insertion by pol eta due to its more open and less constrained active site.

2-Aminopurine↗
PubMed2003

A theoretical study of the insertion barrier of MAO methylaluminoxane)-activated, Cp2ZrMe2-catalyzed ethylene polymerization: further evidence for the structural assignment of active and dormant species.

Density functional theory has been used to calculate the ethylene insertion barrier into the Zr-C bonds of the [Cp2ZrMe](+)[AlMe3Me(A-MAO)]- and [Cp2ZrMe](+)[Me(A-MAO)]- ion pairs where (AlOMe)6 was used to model the active forms of MAO (A-MAO). The results support the proposal that the former is the active and the latter the dormant species in MAO-activated olefin polymerization. For the first insertion, with the active species the trans approach has a lower barrier to insertion than the cis approach in solution, due to the larger ion pair separation. It is likely that the separated ion pairs recombine between subsequent insertions. For the second insertion, we have considered frontside, backside and combined insertion mechanisms showing that the total barrier to insertion is approximately the same in all cases ranging from 13.8 kcal mol(-1)-14.8 kcal mol(-1). For the frontside and combined insertion this barrier is a result of the rotation of the propyl chain: for the backside mechanism it is stems from the ethylene insertion barrier. Comparison of the results for the ion pair and for the naked cation show that in the former case olefin complexation is an endothermic process whereas for the latter it is exothermic. In general, the large ion pair separation prevents the orientation of the anion from exerting much influence on the geometry or energy of the cation. However, when structures with alpha-agostic interactions are considered the ion pair separation is small enough so that the orientation has some influence on the reaction mechanism. For the second insertion, dissociated transition states were found to have lower barriers than associated ones.

Journal Article↗
PubMed1998

Molecular mechanics of two smooth muscle heavy meromyosin constructs that differ by an insert in the motor domain.

Phasic and tonic smooth muscles express two myosin heavy chain isoforms that differ by only a seven amino acid insert in a flexible surface loop located near the nucleotide-binding site. The inserted isoform found predominantly in phasic muscle has two times the actin-activated ATPase activity and in vitro actin filament velocity as the non-insert isoform found mainly in tonic muscle (Kelley, C.A., Takahashi, M., Yu, J.H. & Adelstein, R.S. 1993. J Biol Chem 268, 12848, Rovner, A.S., Freyzon, Y. & Trybus, K.M. 1997. J Musc Res Cell Motil 18, 103). We used a laser trap to characterize the molecular mechanics of the inserted isoform [(+)insert] and of a mutant lacking the insert [(-)insert], which is analogous to the isoform found in tonic muscles. The constructs were expressed in the baculovirus/insect cell system. Unitary displacements (Duni) were similar for both the constructs (approximately 10 nm) but the attachment time (ton) for the (-)insert was two times that of the (+)insert. These data suggest that the insert in the nucleotide-binding loop does not affect the inherent mechanics of the myosin molecule but rather the kinetics of the cross-bridge cycle.

Actins↗
PubMed1999

Pain and mechanical injury of human skin following needle insertions.

Needle insertion is a very common invasive procedure, but little has been done to study how pain is related to the mechanical properties of the needle insertion, and how pain from the procedure may be minimized. The aim of the present study was to investigate the pain evoked by standardized needle insertion into the human skin. Needle insertions were performed with continuous registration of the mechanical force on the needle. Forty consecutive needle insertions to the depth of 8 mm with 27G and 30G needles, 2 and 19 mm/s velocities, and at 45 and 90 degree angles to the skin surface were performed in a randomized and blinded design in 30 healthy volunteers. The occurrence, intensity and quality of pain, as well as the maximum mechanical needle penetration force and the total mechanical workload were registered. The mechanical parameters of needle insertions were significantly related to needle size and velocity of insertion. Occurrence of pain and bleeding were significantly related to the needle size. High needle insertion velocity was significantly related to a higher rate of sharp and pricking pain, and low insertion velocity to a significantly higher rate of dull and burning pain. The present study provides quantitative data on pain and mechanical parameters of standardized needle insertions through normal human skin. Copyright 1999 European Federation of Chapters of the International Association for the Study of Pain.

Journal Article↗
PubMed2002

Variation in insertion of the abductor digiti minimi: an anatomic study.

We dissected 70 cadaver hands to examine the anatomy of the insertion of the abductor digiti minimi (ADM). The insertion had 2 forms. In 58 hands the insertion of the ADM was divided into 2 tendinous portions: one attached the base of the proximal phalanx (bone insertion) and the other attached the extensor aponeurosis (extensor insertion). In 12 hands the bone insertion existed solely. The mean length and width of the bone insertion were 10.6 +/- 3.1 and 4.0 +/- 0.9 mm and those of the extensor insertion were 18.5 +/- 4.0 and 2.1 +/- 1.1 mm, respectively. The mean proportion of the width of the extensor insertion to that of whole tendon was 31% (range, 0% to 50%). These observations show greater variation in the insertional anatomy of the ADM than reported previously.

Aged↗
PubMedDate not supplied

Complications associated with cannula insertion techniques used for laparoscopy in standing horses.

OBJECTIVE: To report our experience and complications associated with different cannula insertion techniques for laparoscopy in standing horses. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Forty horses that had laparoscopy for diagnostic or surgical purposes. METHODS: After a physical examination, including rectal palpation, standing laparoscopy was performed in 40 sedated horses. Local anesthetic was injected at each site of cannula insertion in the left flank. Horses were divided into 5 groups: Pneumoperitoneum was induced before cannula insertion using a Verres needle (group 1, n = 3) or a 12-g catheter (group 2, n = 14); the cannula was inserted before inducing a pneumoperitoneum (group 3, n = 9); the cannula was inserted under visual control, using an operating laparoscope (group 4, n = 2) or a Visiport Optical Trocar (group 5, n = 12). Horses were observed for 7 days. RESULTS: Problems with insufflation or cannula insertion occurred in 12 horses: 6 had peritoneal detachment, 4 had a splenic puncture, and 2 had descending colon puncture. Eleven of these complications occurred in groups 1 to 3 and only 1 in groups 4 and 5. CONCLUSIONS: The Visiport optical device allows controlled insertion of the initial trocar, and thus avoided potential problems associated with "blind" cannula insertion techniques and was used effectively in horses that had feed withheld for 12 hours. This technique enables direct insertion of a cannula directly into the right flank. CLINICAL RELEVANCE: Complications associated with initial cannula insertion in the paralumbar fossa, for laparoscopy, in standing horses can be minimized with the use of an optical cannula.

Anesthetics, Local↗
PubMed1985

Application of the mini-Mu-phage for target-sequence-specific insertional mutagenesis of the herpes simplex virus genome.

An earlier technique for insertional mutagenesis of large viral genomes involved the insertion of the thymidine kinase (TK) gene at a specific target site, cotransfection of the fragment carrying the insertion with the intact viral genome, and selection of the progeny for viral recombinants expressing the TK gene. The inserted TK gene could then be replaced by cotransfection of the recombinant DNA with fragments carrying a foreign sequence or a deletion in the target sequence. To enable the probing of larger target domains and facilitate insertional mutagenesis, we extended this technique by insertion of a 2.2-kilobase-pair (kbp) herpes simplex virus 1 (HSV-1) chimeric alpha TK gene into the 7.5-kbp mini-Mu-phage (alpha TK-mini-Mu) and lysogenized Escherichia coli with the helper Mu phage and the alpha TK-mini-Mu. Induction of phage multiplication of the lysogenized E. coli after transformation with plasmids carrying HSV-1 DNA and subsequent infection of E. coli RecA+ lysogenized with Mu phage yielded plasmid populations carrying randomly inserted alpha TK-mini-Mu DNA. Application of this procedure for insertional mutagenesis of the BamHI B fragment, which spans the junction between the unique and reiterated sequences of the L component of viral DNA, yielded two types of recombinants. Viral recombinant designated RBMu1 contained the intact alpha TK-mini-Mu inserted into unique sequences of BamHI B fragment. In recombinant RBMu2, the alpha TK-mini-Mu was inserted at or in the repeated sequences, but approximately equal to 14 kbp comprising most of the internal reiterations of the viral genome in the prototype arrangement were deleted.

Animals↗
PubMed1998

The MEK1 proline-rich insert is required for efficient activation of the mitogen-activated protein kinases ERK1 and ERK2 in mammalian cells.

MEK1 and MEK2 contain a proline-rich insert not present in any other known MEK (MAP (mitogen-activated protein)/ERK (extracellular signal-regulated kinase) kinase) family members. We examined the effect of removing the MEK1 polyproline insert on MEK activity, its binding to Raf, and its ability to activate ERKs in cells. Deletion of the insert had no effect on either the activity of MEK1 or on its ability to bind to Raf-1. Both wild type and constitutively active MEK1 coimmunoprecipitated with Raf-1 whether or not the insert was present. Deletion of the insert did not reduce activation of MEK1 by EGF or activated Raf in cells. The proline-rich insert enhanced the ability of an otherwise equally active MEK1 protein to regulate endogenous ERKs in mammalian cells. Overexpression of either constitutively active MEK1 lacking the insert or ERK2 compensates for the weaker in vivo activity of the MEK1 deletion mutant. Expression of the insert in cells reduced activation of ERKs by EGF. We conclude that the proline-rich insert is not the site of the MEK-Raf interaction and that the polyproline insert is required for its efficient activation of downstream ERKs in cells.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMedDate not supplied

Capillary vessel network integration by inserting a vascular pedicle enhances bone formation in tissue-engineered bone using interconnected porous hydroxyapatite ceramics.

The aim of the present study was to investigate the possibility of integrating porous hydroxyapatite (HA) ceramics with a capillary vessel network via insertion of a vascular pedicle, and to determine whether this procedure enhances new bone formation in tissue engineering of bone. First, synthetic interconnected porous HA (IP-CHA) was implanted subcutaneously into rat groin with or without insertion of superficial inferior epigastric vessels. At 6 weeks, IP-CHA with vascular insertion contained thick fibrous connective tissue with a number of large blood vessels that seemed to derive from the inserted vascular bundle. Next, IP-CHA loaded with recombinant human bone morphogenetic protein 2 (BMP, 2 or 10 microg/block) was implanted with or without vascular insertion. At 3 weeks, IP-CHA/BMP (10 microg) composite with vascular insertion exhibited abundant new bone formation in the pores of the deep portion close to the inserted vessels. In contrast, IP-CHA/BMP (10 microg) without vascular insertion showed poor bone formation. Histomorphometric analysis demonstrated that vascular insertion significantly increased new bone formation. In IP-CHAs with a lower dose of BMP (2 microg), no bone formation was found, with or without vascular insertion. These results suggest that the present system of integrating a vascular network with IP-CHA is a useful technique for bone tissue engineering.

Animals↗
PubMed2005

Febrile complications following insertion of 100 double-J ureteral stents.

BACKGROUND AND PURPOSE: Implanted foreign bodies are associated with a higher risk of infection. Little has been published on infectious complications associated with ureteral double-J stents. The aim of this study was to define risk factors and characterize the febrile complications of the insertion of double-J stents. PATIENTS AND METHODS: One hundred consecutive cases of retrograde stent insertion (55 men and 45 women) were evaluated retrospectively. Eighty-one patients had an obstructing stone, either in the ureter or at the ureteropelvic junction; 10 had an obstructing tumor; and 9 had hydronephrosis and pain without calculi. Risk assessment was calculated for two major categories: urgent (N = 47) and elective (N = 53) insertion. Potentially confounding factors such as age, sex, accompanying medical problems, and types of prophylaxis were assessed. All but six patients received prophylactic antibiotics prior to stent insertion. RESULTS: All thirteen patients who had fever at the initial evaluation underwent urgent stent insertion. Of the 87 afebrile patients (53 elective and 34 urgent insertions), 22 (25%) developed fever (> or = 38 degrees C) after the procedure. Fever developed in 19 (56%) of the 34 urgent-insertion group who were not originally febrile as opposed to 3 (6%) of the elective-insertion group (P < 0.001). Six of these 22 patients (27%) had a positive urine culture after insertion. None had a positive blood culture, including the 13 patients who underwent the procedure while febrile. CONCLUSIONS: Urgent insertion of a double-J stent is associated with a high risk of fever but a favorable outcome.

Adolescent↗
PubMed1995

An inverse PCR screen for the detection of P element insertions in cloned genomic intervals in Drosophila melanogaster.

We developed a screening approach that utilizes an inverse polymerase chain reaction (PCR) to detect P element insertions in or near previously cloned genes in Drosophila melanogaster. We used this approach in a large scale genetic screen in which P elements were mobilized from sites on the X chromosome to new autosomal locations. Mutagenized flies were combined in pools, and our screening approach was used to generate probes corresponding to the sequences flanking each site of insertion. These probes then were used for hybridization to cloned genomic intervals, allowing individuals carrying insertions in them to be detected. We used the same approach to perform repeated rounds of sib-selection to generate stable insertion lines. We screened 16,100 insert bearing individuals and recovered 11 insertions in five intervals containing genes encoding members of the kinesin superfamily in Drosophila melanogaster. In addition, we recovered an insertion in the region including the Larval Serum Protein-2 gene. Examination by Southern hybridization confirms that the lines we recovered represent genuine insertions in the corresponding genomic intervals. Our data indicates that this approach will be very efficient both for P element mutagenesis of new genomic regions and for detection and recovery of "local" P element transposition events. In addition, our data constitutes a survey of preferred P element insertion sites in the Drosophila genome and suggests that insertion sites that are mutable at a rate of approximately 10(-4) are distributed every 40-50 kb.

Animals↗
PubMed2002

Efficient recovery of centric heterochromatin P-element insertions in Drosophila melanogaster.

Approximately one-third of the human and Drosophila melanogaster genomes are heterochromatic, yet we know very little about the structure and function of this enigmatic component of eukaryotic genomes. To facilitate molecular and cytological analysis of heterochromatin we introduced a yellow(+) (y(+))-marked P element into centric heterochromatin by screening for variegated phenotypes, that is, mosaic gene inactivation. We recovered >110 P insertions with variegated yellow expression from approximately 3500 total mobilization events. FISH analysis of 71 of these insertions showed that 69 (97%) were in the centric heterochromatin, rather than telomeres or euchromatin. High-resolution banding analysis showed a wide but nonuniform distribution of insertions within centric heterochromatin; variegated insertions were predominantly recovered near regions of satellite DNA. We successfully used inverse PCR to clone and sequence the flanking DNA for approximately 63% of the insertions. BLAST analysis of the flanks demonstrated that either most of the variegated insertions could not be placed on the genomic scaffold, and thus may be inserted within novel DNA sequence, or that the flanking DNA hit multiple sites on the scaffold, due to insertions within different transposons. Taken together these data suggest that screening for yellow variegation is a very efficient method for recovering centric insertions and that a large-scale screen for variegated yellow P insertions will provide important tools for detailed analysis of centric heterochromatin structure and function.

Animals↗
PubMed1979

Specificity of insertion by the translocatable tetracycline-resistance element Tn10.

Genetic analysis of 131 independent transpositions of the tetracycline-resistance element Tn10 from a single site in phage P22 into the histidine operon of Salmonella typhimurium reveals that Tn10 insertions are not randomly distributed along this chromosomal target. The insertions occur in 22 different "clusters"; insertions within each cluster are very tightly linked in recombination tests. Tn10 insertions are not evenly distributed among the identified clusters. The existence of these clusters suggests that this chromosomal target contains particular genetic signals that guide Tn10 to particular preferred positions for insertion. Insertions within each cluster occur in both orientations with roughly equal frequency.--The relationship among different insertions within each cluster has been examined. The resolution of genetic mapping places an upper limit of about 50 basepairs on the distance between different insertions within a cluster. Different insertions within a cluster usually have the same reversion frequency; however, heterogeneity in reversion frequency has been detected in at least two clusters. For most clusters, the available data are consistent with the simple possibility that all insertions within a cluster are at identical positions; however, the data do not exclude other possibilities.

Base Sequence↗
PubMed2003

Following the LINEs: an analysis of primate genomic variation at human-specific LINE-1 insertion sites.

The L1 Ta subfamily of long interspersed elements (LINEs) consists exclusively of human-specific L1 elements. Polymerase chain reaction-based screening in nonhuman primate genomes of the orthologous sites for 249 human L1 Ta elements resulted in the recovery of various types of sequence variants for approximately 12% of these loci. Sequence analysis was employed to capture the nature of the observed variation and to determine the levels of gene conversion and insertion site homoplasy associated with LINE elements. Half of the orthologous loci differed from the predicted sizes due to localized sequence variants that occurred as a result of common mutational processes in ancestral sequences, often including regions containing simple sequence repeats. Additional sequence variation included genomic deletions that occurred upon L1 insertion, as well as successive mobile element insertions that accumulated within a single locus over evolutionary time. Parallel independent mobile element insertions at orthologous loci in distinct species may introduce homoplasy into retroelement-based phylogenetic and population genetic data. We estimate the overall frequency of parallel independent insertion events at L1 insertion sites in seven different primate species to be very low (0.52%). In addition, no cases of insertion site homoplasy involved the integration of a second L1 element at any of the loci, but rather largely involved secondary insertions of Alu elements. No independent mobile element insertion events were found at orthologous loci in the human and chimpanzee genomes. Therefore, L1 insertion polymorphisms appear to be essentially homoplasy free characters well suited for the study of population genetics and phylogenetic relationships within closely related species.

Animals↗
PubMed1981

Duplicated rDNA sequences of variable lengths flanking the short type I insertions in the rDNA of Drosophila melanogaster.

We describe cloned segments of rDNA that contain short type I insertions of differing lengths. These insertions represent a coterminal subset of sequences from the right hand side of the major 5kb type I insertion. Three of these shorter insertions are flanked on both sides by a short sequence present as a single copy in uninterrupted rDNA units. The duplicated segment is 7, 14 and 15 nucleotides in the different clones. In this respect, the insertions differ from the 5kb type I insertion, where the corresponding sequence is found only at the right hand junction and where at the left hand side there is a deletion of 9 nucleotides of rDNA (Roiha et al.,1981). One clone is unusual in that it contains two type I insertions, one of which is flanked by a 14 nucleotide repeat. The left hand junction of the second insertion occurs 380 nucleotides downstream in the rDNA unit from the first. It has an identical right hand junction to the other elements and the 380 nucleotide rDNA sequence is repeated on both sides of the insertion. We discuss the variety of sequence rearrangements of the rDNA which flank type I insertions.

Animals↗
PubMed1995

Positions of multiple insertions in SSU rDNA of lichen-forming fungi.

Lichen-forming fungi, in symbiotic associations with algae, frequently have nuclear small subunit ribosomal DNA (SSU rDNA) longer than the 1,800 nucleotides typical for eukaryotes. The lichen-forming ascomycetous fungus Lecanora dispersa contains insertions at eight distinct positions of its SSU rDNA; the lichen-forming fungi Calicium tricolor and Porpidia crustulata each contain one insertion. Insertions are not limited to fungi that form lichens; the lichen ally Mycocalicium albonigrum also contains two insertions. Of the 11 insertion positions now reported for lichen-forming fungi and this ally, 6 positions are known only from lichen-forming fungi. Including the 4 newly reported in this study, insertions are now known from at least 17 positions among all reported SSU rDNA sequences. Insertions, most of which are Group I introns, are reported in fungal and protistan lineages and occur at corresponding positions in genomes as phylogenetically distant as the nuclei of fungi, green algae, and red algae. Many of these positions are exposed in the mature rRNA tertiary structure and may be subject to independent insertion of introns. Insertion of introns, accompanied by their sporadic loss, accounts for the scattered distribution of insertions observed within the SSU rDNA of these diverse organisms.

Base Sequence↗