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At least 883 records · Page 49Linked to original sources
PubMed1995

A new method for identifying the depth of insertion of tracheal tubes.

When a patient's lungs require mechanical ventilation, a plastic breathing tube (tracheal tube, TT) must be inserted through the vocal cords and into the trachea. Although insertion of the TT is a routine procedure, determining the correct depth of insertion is difficult clinically, and may require a chest radiograph. We investigated the accuracy of a simple clinical method for inserting a TT to the correct depth. Typically, an inflatable cuff surrounds the distal circumference of the TT to occlude the gap between TT and tracheal wall. Our technique involves pressing gently with one finger on the front of the lower part of the neck to locate the center of the cuff. We hypothesized that a) a palpating finger can identify the cuff through the tracheal wall, and b) if placed using this technique, the TT will be correctly positioned in the trachea. We studied 79 patients in whom TTs were inserted for general anesthesia. TTs were inserted to a depth determined by the palpation technique. We developed a stylet incorporating a magnetic reed switch which could be inserted through the TT. A magnet with specific field characteristics was passed along the front of the neck to locate the reed switch and confirm the location of the cuff. The TT position in the trachea was then examined with a fiberoptic scope. The palpation technique resulted in optimal positioning of the TT in all subjects and could save approximately $14,268/year in chest radiograph costs in our institution.

Adult↗
PubMed1994

RuvA and RuvB proteins facilitate the bypass of heterologous DNA insertions during RecA protein-mediated DNA strand exchange.

RecA protein-mediated DNA strand exchange between circular single-stranded DNA and linear duplex DNA readily bypasses short (up to 100 base pairs) heterologous inserts in one of the DNA substrates. Larger heterologous inserts are bypassed with decreasing efficiency, and inserts larger than 200 base pairs substantially block RecA-mediated DNA strand exchange. The RuvA and RuvB proteins dramatically facilitate the bypass of larger heterologous inserts. When the RuvA and RuvB proteins are added to an ongoing RecA protein-mediated strand exchange reaction, interior heterologous inserts of 1 kilobase pair are bypassed at significant frequencies. The RuvA, RuvB, and RecA proteins are all required for this activity. Bypass occurs only when homologous sequences are present on both sides of the insert. When the heterologous insert is positioned at either end of the linear duplex substrate, the RuvA and RuvB proteins do not significantly increase product formation in RecA protein-mediated DNA strand exchange reactions. The results suggest an important role for RuvA and RuvB in the bypass of DNA structural barriers during recombinational DNA repair.

Adenosine Triphosphate↗
PubMed1994

Pressure redistribution by molded inserts in diabetic footwear: a pilot study.

A small-scale trial is described to demonstrate and evaluate the redistribution of plantar pressure resulting from the use of custom-molded inserts in the orthopedic shoes of diabetic patients at risk of plantar ulceration. A pressure-measuring insole based on force-sensitive resistor technology enabled the load distribution to be compared using molded inserts and flat inserts fitted into the same shoes. An analysis of the 12 peaks of pressure that could be identified under a discrete metatarsal head of six subjects in the trial showed that the pressure was significantly reduced with the use of molded inserts (flat inserts: 305 +/- 79 kPa; molded inserts: 216 +/- 70 kPa; n = 6 p < 0.005). Technical limitations of the equipment and the difficult choice of match of flat insert to molded for comparison suggest that further studies are required for a definitive result.

Adult↗
PubMed1994

Posterior cruciate supplementing total knee replacement using conforming inserts and cruciate recession. Effect on range of motion and radiolucent lines.

This study was performed to determine if a sagittally curved conforming tibial insert can be used with a retained, but balanced, posterior cruciate ligament without deleterious effects on range of motion (ROM) and tibial radiolucencies, as compared with a flatter insert that is less conforming and does not require cruciate balancing. The authors reviewed 50 consecutive primary knees implanted with flatter posterior lipped inserts and 50 consecutive primary knees with curved inserts and posterior cruciate ligament balancing. The average ROM for both groups was the same postoperatively as preoperatively: 111 degrees for the posterior lipped inserts and 113 degrees for the curved inserts. The incidence of tibial radiolucent lines was 8% for both groups. The authors conclude that sagittally curved, more conforming tibial inserts with retained, but balanced, posterior cruciate ligaments, do not adversely effect ROM and tibial radiolucencies. Their use forms an attractive compromise between the schools of cruciate preservation and cruciate substitution, maximizing their advantages while minimizing their disadvantages. Functional ROM can be achieved while bone stock is preserved, the joint line is restored, and wear characteristics are improved.

Female↗
PubMed1994

Peripherally inserted central catheters in an acute-care hospital.

BACKGROUND: Peripherally inserted central catheterization is a relatively new approach for intravenous therapy in acute-care hospitals. Few studies are available on peripherally inserted central catheters (PICCs) used in adult patients in an acute-care setting. We examine the natural history and outcome of PICC use in our hospital. METHODS: A retrospective review was undertaken of all hospitalized patients who had PICCs inserted in an acute-care, metropolitan teaching hospital for any reason from July 1991 through July 1992. Patients who had PICCs inserted, used, and then removed in the same hospitalization were evaluated. RESULTS: A total of 135 PICCs were inserted in 114 patients. Six PICCs (4.4%) were inserted in intensive care unit settings and 129 (95.6%) in general medical or surgical service. The mean duration catheters were in place before removal was 14.1 days. Sixty-three catheters (46.7%) were removed following completion of therapy. The rate of PICC-related infection was 2.2% (three catheters). The occlusion rate was higher for 20-gauge catheters (18.4%) than for 18-gauge catheters (8.2%) (P = .08). When the rate of complications was compared as a function of catheter use (total parenteral nutrition vs any other use), there was no statistically significant difference (P = .12). Overall complications related to catheter insertion and removal were uncommon. CONCLUSIONS: Based on our study, we conclude that the PICC provides a reasonable and safe alternative to other centrally placed venous devices. In addition, the convenience of maintaining a PICC compared with peripheral intravenous access makes this an attractive method for in-hospital use.

Adult↗
PubMed1994

Wear patterns on retrieved polyethylene tibial inserts and their relationship to technical considerations during total knee arthroplasty.

Fifty-five unconstrained polyethylene tibial inserts were retrieved at revision total knee arthroplasty and examined for evidence of wear after a mean implantation time of 34.2 months (2.5-80 months). Twenty inserts were ultra-high molecular weight polyethylene (UHMWPE) and 35 were carbon-reinforced polyethylene. Topographic maps of the articular and metal-backed surfaces of each component were constructed to characterize the extent and location of polyethylene degradation, identified visually by mode. In 32 of the retrieved inserts, pre- and postarthroplasty or prerevision radiographs were analyzed for component positioning, sizing, and extremity alignment. These factors then were compared with the patterns and severity of polyethylene wear on the inserts to establish correlations. Severe generalized articular wear was seen in inserts with third body wear from patellar metal-backed failure and cement debris. Severe localized delamination wear was seen in inserts with rotational-subluxation patterns of wear (p = 0.05). The external rotation subluxation wear pattern was strongly associated with knees that had lateral subluxation of the patella (p = 0.0002). Articular wear and cold flow into screw holes tended to be greater in the tightest prearthroplasty compartment (medial in the varus knee [p = 0.0157]; lateral in the valgus knees [p = 0.0226]). Fourteen of 16 knees with a preoperative varus deformities--even when corrected to a normal postarthroplasty anatomic axis--still had greater medial compartment articular wear (p = 0.001). Twelve of these knees did not have a medial release at the time of initial arthroplasty. Preoperative varus also was found to be related to the occurrence of posteromedial cold flow of polyethylene into tibial tray screw holes (p = 0.007). Increasing tibial insert posterior slope was associated with increasingly posterior articular wear track location (p = 0.03). This study indicates that unconstrained tibial component wear patterns and severity may be associated with clinical and mechanical factors under the surgeon's control, including component size and position, and knee alignment and ligament balance.

Adult↗
PubMed1994

The laryngeal mask airway in pediatric patients: factors affecting ease of use during insertion and emergence.

Use of the laryngeal mask airway (LMA) permits the maintenance of a patent airway with successful insertion rates of the LMA on the first attempt varying between 67%-92% in children. The recommended insertion technique involves deflation of the mask using a syringe, and application of a lubricant jelly. In a randomized study of 122 children, we compared the time to complete LMA insertion, the number of attempts before successful placement, and the occurrence of laryngospasm and Spo2 < 90% during insertion using the standard deflated method and an alternative method of insertion with the LMA cuff partially inflated. Independently, the children were randomly assigned to have K-Y sterile lubricating jelly or 2% lidocaine topical solution applied to the back of the mask. The occurrence of coughing, laryngospasm, and vomiting during emergence were recorded. Insertion of the LMA partially inflated required significantly less time (16 vs 23 s, P < 0.05), and was associated with a higher success rate on first attempts (85.5% vs 96.7%, P < 0.05). In those who did not receive morphine, 2% lidocaine topical solution decreased the incidence of coughing on emergence (10.3% vs 36.4%). The ease of insertion of the LMA in children was improved by partial inflation of the cuff and in addition, 2% lidocaine topical solution was as beneficial as morphine in reducing coughing on emergence.

Adolescent↗
PubMed1993

[A study of infusional port re-insertion in patients with liver metastasis].

We evaluated the importance and usefulness of re-insertion of the intra-arterial infusion catheter in 10 patients with liver metastasis who showed problems in the catheter or system during intra-arterial infusion chemotherapy. The route of re-insertion was laparotomy-->left subclavian method in 3 patients, left subclavian-->left subclavian method in 5, and left subclavian-->femoral method in 2. The cause of re-insertion was dislocation in 5 patients, obstruction of the system in 4, and obstruction of CHA in 1. In the patients showing dislocation, re-insertion was performed after a mean of 4 months, and CEA improvement and direct effects evaluated by imaging techniques were marked, suggesting good indication. In the patients showing system obstruction or CHA obstruction, re-insertion was performed after a mean of 8.6 months, and CEA improvement and direct effects were less than those in the patients showing dislocation. Of the 10 patients who underwent re-insertion, 5 have survived to the present for 13-20 months (mean, 17 months). The prognosis of liver metastasis may be improved by active re-insertion of the intra-arterial infusion catheter.

Aged↗
PubMed1995

Effect of glass inserts on resin composite wear.

PURPOSE: To determine the in vitro wear resistance and microstructural stability of composites in which the beta quartz insert was used. MATERIALS AND METHODS: Three different sized inserts were used in conjunction with P-50 and Herculite XR posterior resin composites. The study was designated to create varying gap dimensions between the insert and wall of the preparation (0.75, 1.25 and 1.50 mm). In addition, one half of the inserts contacted the dentin floor of the cavity whereas the other half rested on 1.0 mm of composite. The controls consisted of resin composite only. Using an in vitro wear testing device, all specimens were subjected to 400,000 cycles of masticatory loading. Upon completion of testing, profilometric tracings and SEM were used to determine relative wear, patterns of wear and microstructural changes. Differences, in wear values were analyzed by two-way ANOVA. RESULTS: The wear values for P-50 and Herculite XR controls were 24.8 and 31.3 micrometers, respectively. No significant differences were detected (P<0.05) in amount of wear between the control specimens and the insert specimens, regardless of size. The same results were obtained regardless of whether the insert rested on dentin or resin composite. SEM evaluations however, revealed excellent interfacial continuity after wear testing. While the inserts did not influence the wear resistance, they may provide an excellent means for maintaining functional occlusion.

Analysis of Variance↗
PubMed1996

Analysis of a hot spot for DNA insertion suggests a mechanism for Ig switch recombination.

We recently reported that transfected DNA inserts into the VDJ-Cmu intron much more frequently than into average DNA, and that insertion within this intron occurs preferentially into the switch region. To gain information about the mechanisms involved in DNA insertion, we sequenced the 5' and 3' junctions of typical transformants. Although the junction sequences did not indicate a preferred insertion motif within the switch region, our results suggest that joining of the transfected and chromosomal DNAs is facilitated by short regions of identity. Our analysis of the insertions into the non-switch part of the intron suggests that breakage of the chromosomal DNA occurs preferentially at sites that are flanked by short complementary sequences. This correlation suggests that the self-complementary DNA might form short stem-loops, which, in turn, are prone to enzymatic cleavage and thus facilitate the insertion of transfected DNA. A model is proposed in which this effect can account for both the higher than average frequency of insertion into the VDJ-Cmu intron and the preference for the switch region within this intron. An extension of this model is proposed to explain why the repetitive switch regions are the preferred breakage/rejoining sites for isotype switch rearrangements.

Animals↗
PubMed1997

Assessment of primary and salvage lateral mass screw insertion torque in a cadaveric model.

This study was performed to determine the insertion torques of three types of lateral mass screws and to explore their relationship to bone mineral density (BMD). The peak insertion torque of primary articular screws was measured, and the holes were then stripped by overtightening. Larger diameter "salvage" screws were placed in the stripped holes, and peak insertion torque was measured. Peak primary screw insertion torque and BMD were positively correlated (r = 0.48, p = 0.00001). The ratio of salvage to primary screw insertion torque varied significantly among the systems (p = 0.0003). The positive correlation between BMD and primary screw peak insertion torque confirms the importance of bone density for satisfactory screw purchase. The large variation in the ratio of salvage to primary screw insertion torque among systems may be due to differences in primary and salvage screw design.

Bone Density↗
PubMed1997

The diamond-coated sonic scaler tip. Part I: Oscillation pattern of different sonic scaler inserts.

The authors have developed a set of four modified sonic scaler inserts with variously shaped shafts and diamond-coated budded inserts. The inserts are specially designed for the furcation area since instruments used hitherto have not been successful in completely preventing slow continuous periodontal breakdown in multirooted teeth. To test their clinical effectiveness, the displacement amplitude of the different sonic scalers was measured under varying load applications. Each scaler insert generated different and characteristic displacement amplitudes from rest position. The conventional insert was continuously dampened under increasing load application, whereas the diamond-coated inserts showed only minor variations of oscillation pattern. In a clinical situation, both insert types should be used, with the least possible application load to maintain effectiveness and minimize removal of hard tissue.

Dental Scaling↗
PubMed1995

Analysis of human immunodeficiency virus type 1 promoter insertion in vivo.

Our study reports the occurrence of HIV-1 insertional activation events in vivo. Using a previously described PCR assay, small aliquots of broncho-alveolar lavage (BAL) cells obtained from AIDS patients were analyzed. Nine percent (5/54) of the aliquots contained proviral-host sequence transcripts indicating HIV-1 promoter insertion, whereas multiply spliced HIV-1 mRNAs were found in 28% (15/54) of the aliquots. In four of five events, insertions affect distinct cellular transcription units expressed in a T-cell line. To establish a ratio between provirus integration and promoter insertion events, an in vitro infection study was performed and transcripts containing HIV-1 and K-ras or CD4 gene sequences, respectively, were monitored. Given the randomness of retrovirus integration, 170 sense-oriented HIV integrations into these gene loci were predicted to occur. Three distinct promoter insertion events were observed, indicating that 1.8% of integrated proviruses transcribed adjacent genes. Based on this result and a mean of 257 proviral copies per 10(6) BAL cells, we would expect to observe 25 promoter insertion events in our in vivo study. That only five events were found may be due to the lower transcriptional activity of HIV-1 in vivo than that in cell cultures.

Acquired Immunodeficiency Syndrome↗
PubMed1999

A single nucleotide insertion in the 5'-untranslated region of hepatitis C virus leads to enhanced cap-independent translation.

The 5'-untranslated region (5'-UTR) of hepatitis C virus (HCV) contains an internal ribosome entry site (IRES) that directs translation of the viral open reading frame (ORF). The 5'-UTR consists of 341 nucleotides (nt) in most strains, and multiple segments within this region are important for its IRES activity. Sequencing analysis of a full-length HCV cDNA clone derived from a Japanese HCV1b-positive patient showed the 5'-UTR was 342 nt long due to a nucleotide T insertion at position 207. The influence of this T insertion on the IRES activity in directing cap-independent translation was investigated. The IRES of the 5'-UTR342 was approximately five- and two- to sevenfold more active in directing luciferase expression in monocistronic and bicistronic expression systems, respectively, when compared with the IRES of the 5'-UTR341 of a previously reported HCV1b strain. In addition to the T insertion, another point mutation involving an A to C transition at position 119 was also present in the 5'-UTR342. Simultaneous comparison of the IRES activities in engineered constructs that contained each of the two mutations indicated that the insertion at position 207 is responsible for the enhanced IRES activity of the 5'-UTR342. Further determination of the abilities of the engineered 5'-UTRs harbouring A, G, or C insertions at the same position to initiate translation indicated that both T and non-T nucleotide insertions lead to enhanced cap-independent translation.

5' Untranslated Regions↗
PubMed2000

Broad-range bacteriophage resistance in Streptococcus thermophilus by insertional mutagenesis.

Streptococcus thermophilus is a lactic acid bacterium used in industrial milk fermentation. To obtain phage-resistant starters, S. thermophilus strain Sfi1 was submitted to mutagenesis with the thermolabile insertional vector pG(+)host9:ISS1 followed by a challenge with the lytic S. thermophilus phage Sfi19. Vector insertions into four distinct sites led to a phage-resistance phenotype. Three mutants were characterized further. They were protected against the homologous challenging phage and 14 heterologous phages. All three mutants adsorbed phages. No intracellular phage DNA synthesis was observed in mutants R7 and R71, while mutant R24 showed a delayed and diminished phage DNA synthesis compared to the parental Sfi1 strain. In mutant R7 a short deletion occurred next to the insertion site which removed the upstream sequences and the 15 initial codons from orf 394, encoding a likely transmembrane protein. Analogy with other phage systems suggests an involvement of this protein in the phage DNA injection process. In mutant R24 the vector was inserted into orf 269 predicting an oxido-reductase. When the vector sequence was removed via homologous recombination across the duplicated insertion elements, mutant R24 returned to the phage susceptibility of the parental strain. This observation suggested that inactivation of orf 269 was not crucial for the resistance phenotype. A gene encoding a likely restriction subunit of a type I restriction-modification system was located directly downstream of the insertion site in mutant R24. hsdM and hsdS genes encoding the modification and specificity subunits of a type I R-M system and biological evidence for an active R-M system were detected in strain Sfi1, suggesting involvement of a type I R-M system in the resistance phenotype of R24.

Amino Acid Sequence↗
PubMed2000

Insertion of cellular NEDD8 coding sequences in a pestivirus.

For the cytopathogenic (cp) bovine viral diarrhea virus (BVDV) strain CP 821, a duplication of the genomic region encoding part of NS2, NS3, NS4A, and part of NS4B together with a nonviral insertion was detected. Further analyses including molecular cloning and sequencing of the putative cellular recombination partner showed that the insertion in CP 821 originated from a bovine mRNA encoding the cellular protein NEDD8, which is 58% identical to ubiquitin. To our knowledge the genome of CP 821 represents the first viral RNA with a NEDD8 coding insertion. Remarkably, the insertion site differs from that described for insertions of ubiquitin. The NEDD8 sequence allows an additional cleavage of the viral polyprotein, whereby an NS3 with an unusual N-terminus is generated. Furthermore, the CP 821-specific genomic alterations were introduced into an infectious noncytopathogenic (noncp) BVDV cDNA clone. After transfection of bovine cells with the respective RNA, a cp virus was recovered. This showed that the NEDD8 coding insertion together with the duplicated viral sequences represents the genetic basis for cytopathogenicity of CP 821. In addition to the recovered cp virus, noncp BVDV rapidly evolved after transfection. This is the first time that a change from the cp to the noncp phenotype was demonstrated in the course of replication in tissue culture cells.

Amino Acid Sequence↗
PubMed1998

Small insertions at a shared position in the SSU rDNA of lecanorales (lichen-forming ascomycetes).

Small insertions are reported from the SSU rDNA of the genera Cladonia, Cladina, Stereocaulon, Pertusaria and Physcia (lichen-forming Lecanorales, Ascomycetes). The insertions range in length from 56 to 81 nucleotides, and occur at a shared position, 330 (relative to Escherichia coli), in a semi-conserved region of the SSU rDNA. These small insertions have a simple secondary structure with two stem-loops, and may represent degenerate group-I introns. Species of the same genus often have small insertions of similar lengths, secondary structures and sequences. These similarities suggest that the insertions are homologous and can provide phylogenetic information to support current classifications. Variable sequences of rDNA, such as the small insertions and group-I introns, may be powerful tools for resolving evolutionary relationships among genera and species.

Ascomycota↗
PubMed2004

A large MSH2 Alu insertion mutation causes HNPCC in a German kindred.

Hereditary non-polyposis colorectal cancer (HNPCC) syndrome is an autosomal, dominantly inherited disease accounting for about 1%-5% of all colorectal cancer cases. HNPCC predisposition is caused by germline mutations in at least five genes coding for DNA mismatch repair (MMR) proteins. More than 400 MMR gene mutations have been identified in HNPCC patients. About 90% of mutations affect the MLH1 and MSH2 genes. The mutational spectrum mainly includes point mutations and small deletions or insertions. Here, we report a large 184 base-pair Alu insertion mutation in exon 6 of the MSH2 gene in a German HNPCC family. The inserted sequence contains repetitive Alu sequence elements that present the highest homology with the old Alu J subfamily. The Alu J insertion was most likely derived from Alu-mediated recombination, since Alu J elements have been found close to the insertion site in adjacent introns, and since elements pivotal for Alu retrotransposition are missing. Our results suggest that the recombination event occurred at least one generation ago. This is the first report of an Alu insertion in the coding sequence of a MMR gene as the cause of HNPCC. Our data thus further extend the spectrum of MMR gene mutations causative for HNPCC.

Aged↗