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At least 1,297 records · Page 72Linked to original sources
PubMed1991

[An attempt at a mathematical prediction of the depth of insertion of the needle in peridural anesthesia].

The purpose of the investigation was to correlate the distance from the skin to the flaval ligament with the individual data of patients such as bodyweight, height, sex and age with the aim of predicting the depth of insertion of the needle. In a retrospective study we examined 448 patients (217 men and 231 women). In the anaesthetic records the depth of insertion of the needle was noted together with the patients' personal data. Evaluation of the material showed that there is no correlation of statistically significant relevance between the depth of insertion and the bodyweight and age of the patient, but there is a correlation between depth of insertion on the one hand and the variables bodyweight, overweight and the quotient body height/weight on the other. This correlation showed a somewhat higher significance in women than in men. The correlation can be expressed in a formula like y = K + fx, whereby for the relation between depth of insertion and body weight the equation for men is y = 1.87518 + 0.02761x. The equation for women is y = 2.23985 + 0.03559x. With these formulae a rough prediction for the depth of insertion can be made, with x representing the bodyweight and y the expected depth in cm. The measured values fluctuated between 3.5 and 7.4 cm in the 217 men, with the medium value at 4.08 cm. In the 231 women the measured values fluctuated between 3.3 and 6.9 cm with the medium value at 4.67 cm.

Adolescent↗
PubMed1990

Use of a cannula insert in erratic emptying Heidenhain pouch dogs: effect of single and cumulative doses of omeprazole.

A novel cannula insert was used to correct erratic emptying in Heidenhain pouch dogs. The insert restored the recovery of histamine or pentagastrin stimulated gastric acid secretion to that obtained from normal emptying pouch dogs, probably by displacing obstructing tissue within the pouch. Use of the insert did not cause any discomfort to the animals, nor did it alter basal secretion. There was no significant difference between the antisecretory activity of single doses of omeprazole in erratic emptying animals fitted with the insert (ED50 = 0.21 mumol/kg) and in dogs with a normal pouch (ED(50) = 0.13 mumol/kg). Use of the insert achieved an earlier steady secretory response which allowed cumulative dosing to be performed in each animal. There was no significant difference between the effect of cumulative (ED50 = 0.24 mumol/kg) and single doses of omeprazole in erratic emptying dogs. Although there was a significant difference between cumulative dosing in erratic emptiers and single dosing in normal animals it should still be possible to use erratic emptiers with the insert for screening purposes.

Animals↗
PubMed1990

Manufacturer's information insert and subjective theophylline side-effects.

In Western Europe medicine packages contain an insert prepared by the manufacturer which enumerates the drug side-effects. We investigated the influence of this insert on alleged theophylline side-effects. Forty literate adult asthmatics were randomly allocated into two groups (n = 20 each): theophylline packages contained the manufacturer's insert in group A but not in group B. Theophylline was prescribed (10 mg.kg-1 body weight qd) for one week. During this period the patients filled a diary grading 13 different symptoms from 0 to 3; 5 of these symptoms were listed on the insert as theophylline side-effects. On the eighth day the patients were interviewed and theophylline blood levels measured. Theophylline side-effects were significantly more marked in group A than in group B, whereas the other symptoms were of similar magnitude. Eight patients prematurely stopped their treatment in group A vs 3 in group B, because of alleged intolerance. Theophylline blood levels did not differ significantly in the two groups; neither did they in the subgroup which stopped treatment and in the one which complied to prescription. We conclude that side-effects were suggested to the patients by the insert and/or that the insert increased their awareness of side-effects, with a subsequent detrimental influence upon compliance to therapy.

Adult↗
PubMed1989

A dipeptide insertion in domain I of exotoxin A that impairs receptor binding.

Deletions within the structural exotoxin A gene of 27 or 119 amino acids in domain I of the mature polypeptide, or of 88 or 105 amino acids in domains I and II, resulted in the synthesis of exotoxin A (ETA) polypeptides that were not secreted from Pseudomonas aeruginosa hosts but were localized in the cell membrane. Insertions of a hexanucleotide sequence, either pCGAGCT or pCGAATT, at TaqI sites within the gene resulted in variant exotoxin A polypeptides which were secreted normally. pCGAGCT causes insertion of either Glu-Leu or Ser-Ser in the amino acid sequence of the toxin, while pCGAATT causes insertion of either Glu-Phe or Asn-Ser dipeptides. Although the cytotoxicity of eight variants was unimpaired, that of four others was reduced, and one variant which had a Glu-Phe insert between residues 60 and 61 (ETA-60EF61) was 500-fold less cytotoxic than wild-type exotoxin A. Purified ETA-60EF61 dissociated much faster from mouse LMTK- cells than wild-type ETA, suggesting that the insertion impaired the ability of ETA-60EF61 to interact with exotoxin A receptors. The location of the insert is within a major concavity on the surface of domain I of the exotoxin A molecule, suggesting that this concavity is important for toxin-receptor interaction.

ADP Ribose Transferases↗
PubMed1987

[Duration and complications following grommet insertion in childhood].

We report 1000 insertions of ventilation tubes in 534 children for secretory otitis media (SOM) within a period of 6 years. In 77.5% of the cases, the air-bone gap was greater than 20 dB. The grommets are allowed to undergo spontaneous expulsion which happened in 319 ears, about 7 months after insertion. SOM recurred in 32.6% of the cases once, in 5.0% of the cases twice, and in 1.9% three times, requiring re-insertion of grommets. Recurrence appeared between 4 and 65 months after the first insertion. In three cases perforations of the tympanic membrane persisted and required tympanoplasty. Tympanometric examination and pure tone audiometry are necessary, in addition to pure tone audiometry to follow up successfully ventilated middle ears and to show recurrence as early as possible. Pre-existing but unsuspected sensorineural hearing loss was discovered in 10 cases. The deprivation of neural auditory pathways in early childhood and the possible retardation of speech development caused by SOM are mentioned. Normal hearing is the most important goal of therapy in children suffering from SOM, and insertion of ventilation tubes is the preferred method of achieving that goal safely. Adenoidectomy and treatment of upper airway infections are indispensable parts of the therapy of SOM. Regular follow up after insertion of grommets and even after their expulsion is necessary because of the high rate of late recurrence of SOM. Induction of cholesteatoma by grommets was not observed.

Acoustic Impedance Tests↗
PubMed1986

The origins and insertions of the extraocular muscles: development, histologic features, and clinical significance.

The tendinous origins and insertions of the extraocular muscles were studied embryologically by macroscopic and microscopic methods. It is concluded from this investigation that these tendons of origin and insertion arise from mesenchymal tissue similar to that of their respective muscles. These tendon-muscle groups have developed from superior and inferior mesenchymal complexes. The origins of the extraocular muscles are attached to the periorbita by an interlocking of the tendinous and muscular fibers, which allows for mobility of the extraocular muscles in all extreme directions of gaze and also results in a strong mechanical mooring for these muscles. Avulsion at the origins of the extraocular muscles following severe traction or trauma is rare. The additional origin of the superior and medial rectus muscles to the dura of the optic nerve explains the pain that may occur on movement of the eye in optic neuritis. Optic nerve compression and thyroid myopathy is explained by mucopolysaccharide and inflammatory cell infiltration of the muscular interdigitations that extend up to the site of origin of the rectus muscles. Findings of this investigation suggest that the association of ptosis and superior rectus muscle underaction may be due to a persistence of fibrous tissue that has endured from embryologic development between the superior rectus and levator palpebrae superioris muscles. Superior oblique tendon sheath syndrome is explained by embryologic strands remaining between the tendon of the superior oblique muscle and the trochlea. The insertions of the rectus muscles extend from the equator of the eye to the limbus early on in development. By processes of differential degeneration between the sclera and the rectus tendon, posterior recession of the tendon from the limbus, and contemporaneous growth of the anterior segment of the eye, these tendons reach their adult location only between the ages of 18 months and 2 years. In strabismus surgery, measurements for muscle adjustments should be assessed from the limbus rather than from the sites of insertion of these tendons. In the series of patients with esotropia, no mechanical abnormalities were noted in relationship to the insertions of the medial or lateral recti muscles. Furthermore, no correlation was found between the site of insertion of the medial rectus muscle and the degree of esotropia.

Child, Preschool↗
PubMed1987

DNA polymerase insertion fidelity. Gel assay for site-specific kinetics.

A quantitative assay based on gel electrophoresis is described to measure nucleotide insertion kinetics at an arbitrary DNA template site. The assay is used to investigate kinetic mechanisms governing the fidelity of DNA synthesis using highly purified Drosophila DNA polymerase alpha holoenzyme complex and M13 primer-template DNA. Km and Vmax values are reported for correct insertion of A and misinsertion of G, C, and T opposite a single template T site. The misinsertion frequencies are 2 X 10(-4) for G-T and 5 X 10(-5) for both C-T and T-T relative to normal A-T base pairs. The dissociation constant of the polymerase-DNA-dNTP complex, as measured by Km, plays a dominant role in determining the rates of forming right and wrong base pairs. Compared with Km for insertion of A opposite T (3.7 +/- 0.7 microM), the Km value is 1100-fold greater for misinsertion of G opposite T (4.2 +/- 0.4 mM), and 2600-fold greater for misinsertion of either C or T opposite T (9.8 +/- 4.2 mM). These Km differences indicate that in the enzyme binding site the stability of A-T base pairs is 4.3 kcal/mol greater than G-T pairs and 4.9 kcal/mol greater than C-T or T-T pairs. In contrast to the large differences in Km, differences in Vmax are relatively small. There is only a 4-fold reduction in Vmax for insertion of G opposite T and an 8-fold reduction for C or T opposite T, compared with the correct insertion of A. For the specific template T site investigated, the nucleotide insertion fidelity for Drosophila polymerase alpha seems to be governed primarily by a Km discrimination mechanism.

Base Composition↗
PubMed1984

Species-restricted target cell lysis by human complement: complement-lysed erythrocytes from heterologous and homologous species differ in their ratio of bound to inserted C9.

The cytolytic efficiency of the terminal complement complex (C5b-9) against erythrocytes of different species is, in part, dependent on the species of C9 origin. In the present study, we have examined the interaction of C9 with erythrocytes in terms of the binding, dimerization, and insertion of C9 into the membranes of sheep and human erythrocytes lysed by human complement (C). The membranes of these C-lysed erythrocytes were analyzed for bound, dimerized, and inserted C9 by a combination of photolabeling, SDS-PAGE, electroblotting, and immunostaining techniques. We found that neither binding nor dimerization of C9 could be correlated with the relative hemolytic efficiency of human C on these erythrocytes, but that C9 insertion into the membranes of these cells varied in direct relation to the extent of lysis. Interestingly, the binding of C3 to these cells under conditions of equivalent C1 fixation also correlated with lytic efficiency. These data indicate that the C9-related differences in the cytolytic efficiency of C against erythrocytes from different species is primarily due to the efficiency of C9 insertion into these cells. Moreover, these data emphasize that neither the binding of C9 to a target membrane nor the formation of C9 dimers necessarily leads to the insertion of C9 into the membrane, suggesting the presence of membrane-bound but inactive C5b-9 complexes. Because the extent of C3 binding also correlated with the relative degree of lysis of sheep vs human erythrocytes, the possibility exists that surface-bound C3 may regulate hemolysis by directing the insertion of C9 in terminal complexes into cells.

Animals↗
PubMed1982

An anatomical reevaluation of rectus muscle insertions.

Certain strabismus operations require a thorough knowledge of the anatomy of rectus muscle insertions. Earlier anatomical studies were based on a small sample size and did not use precise microscopic techniques for measurements. To obtain accurate measurements of rectus muscle insertion relationships, 100 consecutive normal adult autopsy eyes were examined with a Vernier caliper and a dissecting microscope for high magnification. Statistical analysis of these data provided a set of normal values for (1) distances from anterior and posterior limbus to rectus muscle insertions, (2) distances between anterior and posterior limbus, (3) length of line ("width") of rectus muscle insertions, and (4) distances between rectus muscle insertions. Although most of the determinations were somewhat similar to older previous studies, statistically they were significantly different. The ophthalmologist can make use of the revised set of figures for rectus muscle insertion relationships in operations such as transposition procedures for A-V patterns and cranial nerve palsies, large recessions, and advancements in reoperations after recessions.

Adult↗
PubMed1980

An anatomical reevaluation of rectus muscle insertions.

Certain strabismus operations require a thorough knowledge of the anatomy of rectus muscle insertions. Earlier anatomical studies were based on a small sample size and did not use precise microscopic techniques for measurements. To obtain accurate measurements of rectus muscle insertion relationships, 100 consecutive normal adult autopsy eyes were examined with a Vernier caliper and a dissecting microscope for high magnification. Statistical analysis of these data provided a set of normal values for (1) distances from anterior and posterior limbus to rectus muscle insertions, (2) distances between anterior and posterior limbus, (3) length of line ("width") of rectus muscle insertions, and (4) distances between rectus muscle insertions. Although most of the determinations were somewhat similar to previous studies, statistically they were significantly different. The ophthalmologist can make use of the revised set of figures for rectus muscle insertion relationships in operations such as transposition procedures for A-V patterns and cranial nerve palsies, large recessions, and advancements in reoperations after recessions.

Adult↗
PubMed1995

Insertion of glycophorin A, a transmembraneous protein, in lipid bilayers can be mediated by electropermeabilization.

Transmembraneous back-insertion of a solubilized membrane protein, glycophorin A, has been obtained in 1,2 dipalmitoyl-sn-glycero-3-phosphocholine (Pam2GroPCho) cell-size-like liposomes by submitting the lipid/protein mixture to calibrated electric field pulses. Field conditions which are prone to trigger glycophorin insertion are similar to those which mediate lipid layer electropermeabilization. The efflux of calcein, trapped in the liposomes during their preparation, was observed only when field strength is higher than 1.3 kV/cm. Electroinsertion was detected only above the same critical field intensity. Calcein efflux as well as glycophorin insertion were increased by increasing field intensity, pulse duration and/or number of pulses. Experimental evidence of protein insertion was provided by physico-chemical as well as biochemical methods. Direct observation of the pulsed vesicles under the microscope revealed the insertion by means of immunofluorescence and fluorescence. Electroinsertion of fluorescent glycophorin A revealed that the inner bilayers were also labeled. The gel-to-liquid phase transition temperature of Pam2GroPCho decreased after insertion but its cooperativity was not affected. A narrow 31P-NMR peak was observed after electroinsertion showing that the polar headgroups of phospholipids had been altered. Analysis of trypsin-digested peptides revealed that the two trans-orientations of the protein across the external lipid layer were present after electroinsertion. Localized perturbation of the polar headgroup region of phospholipids, which supports the transient permeabilization of lipid layers, allows spontaneous transinsertion of glycophorin across the lipid bilayers.

Electromagnetic Fields↗
PubMed1994

Synergistic insertion of two hydrophobic regions drives Sec-independent membrane protein assembly.

We have studied the membrane insertion of two proteins from the inner membrane of Escherichia coli, both with two transmembrane segments connected by a short periplasmic loop: the M13 procoat protein and a mutant "inverted" leader peptidase. Neither molecule depends on the Sec machinery for insertion. We show that the introduction of a charged residue in the second transmembrane segment completely blocks insertion of both proteins. In contrast, a Sec-dependent procoat mutant, where the periplasmic region has been lengthened, inserts into the membrane even in the presence of a charged residue in the second hydrophobic domain. In addition, a large deletion within the second transmembrane domain of the leader peptidase mutant allows membrane translocation, but only under conditions where the SecA protein is functional. Furthermore, we show that the first hydrophobic domain is required for insertion of the short periplasmic loop of the "inverted" leader peptidase. These results suggest that Sec-independent insertion occurs by a synergistic entry of the two neighboring hydrophobic domains into the lipid bilayer.

Bacterial Proteins↗
PubMed1994

Prevention of central venous catheter-related infections by using maximal sterile barrier precautions during insertion.

OBJECTIVE: In many hospitals, the only sterile precautions used during the insertion of a nontunneled central venous catheter are sterile gloves and small sterile drapes. We investigated whether the use of maximal sterile barrier (consisting of mask, cap, sterile gloves, gown, and large drape) would lower the risk of acquiring catheter-related infections. DESIGN: Prospective randomized trial. SETTING: A 500-bed cancer referral center. METHODS: We randomized patients to have their nontunneled central catheter inserted under maximal sterile barrier precautions or control precautions (sterile gloves and small drape only). All patients were followed for 3 months postinsertion or until the catheter was removed, whichever came first. Catheter-related infections were diagnosed by quantitative catheter cultures and/or simultaneous quantitative blood cultures. RESULTS: The 176 patients whose catheters were inserted by using maximal sterile barrier precautions were comparable to the 167 control patients in underlying disease, degree of immuno-suppression, therapeutic interventions, and catheter risk factors for infections (duration and site of catheterization, number of catheter lumen, catheter insertion difficulty, reason for catheter removal). There were a total of four catheter infections in the test group and 12 in the control group (P = 0.03, chi-square test). The catheter-related septicemia rate was 6.3 times higher in the control group (P = 0.06, Fisher's exact test). Most (67%) of the catheter infections in the control group occurred during the first 2 months after insertion, whereas 25% of the catheter infections in the maximal sterile precautions group occurred during the same period (P < 0.01, Fisher's exact test). Cost-benefit analysis showed the use of such precautions to be highly cost-effective. CONCLUSION: Maximal sterile barrier precautions during the insertion of nontunneled catheters reduce the risk of catheter infection. This practice is cost-effective and is consistent with the practice of universal precautions during an invasive procedure.

Adolescent↗
PubMed1993

A randomized comparison of Verres needle and direct trocar insertion for laparoscopy.

Two hundred and fifty-two women scheduled to undergo laparoscopy were randomly assigned to a Verres needle or direct insertion group. The groups were similar with respect to incidence of obesity, prior surgical treatment, indication for operation and level of training of the surgeon performing the procedure. There were no major complications associated with either technique. Minor complications (preperitoneal insufflation, failed entry or more than three attempts necessary to enter the peritoneal cavity with the trocar) were significantly more frequent (p < 0.05) in the Verres needle technique group. One hundred and thirteen of these patients underwent sterilization procedures. The mean times for performance of the laparoscopic procedure using the direct insertion and Verres needle techniques was 15.3 and 19.6 minutes, respectively. The time saved using the direct insertion technique is explained by a significant (p < 0.01) reduction in the mean laparoscope insertion time, which was 2.2 minutes and 5.9 minutes for the direct insertion and Verres needle techniques, respectively. We prefer the direct insertion technique for trocar placement because it has fewer minor complications and requires less operating time.

Female↗
PubMedDate not supplied

Reduction of marginal gaps in composite restorations by use of glass-ceramic inserts.

The objective of this study was to evaluate the effects of glass-ceramic inserts on reducing the marginal gaps caused by polymerization shrinkage in composite restorations. A light microscope was used to measure the largest gap at margins around restorations made in glass cylinders and tooth cavities with and without adhesion promoters. Where the cylinder was not silanated, the average gap was less in samples containing an insert than in those without. Two preparations were made in the dentin of 20 human molars. In each molar one cavity was restored with a dentin bonding agent and composite and the other with a dentin bonding agent and an insert seated in the composite. The average maximum gap width of restorations containing inserts was statistically less than for those with only composite (paired t-test, P<0.0001). When considering the volume of composite displaced by the insert, these results that the use of a glass-ceramic insert decreased the marginal gaps resulting form polymerization shrinkage.

Ceramics↗
PubMed1996

Biomechanics of rigid tibial nail insertion sites.

The use of a very proximal insertion site for rigid intramedullary nailing was evaluated in a biomechanical study. The purpose of this study was to compare the bursting strains generated in a proximal tibia fracture fragment during rigid nailing, using the recommended insertion sites versus a more proximal site just anterior to the tibial plateau in the midline. Proximal one-third tibia fractures were created in 12 pairs of fresh cadaver specimens. Strain gauges were applied to the medial and lateral cortices of the proximal fragments. Lottes nails, Grosse-Kempf nails, and unreamed Russell-Taylor nails were inserted in four successive pairs of specimens. In each pair, one side used the recommended starting point, and the other side used the proximal insertion site. The strain was recorded at successive 2- to 4-cm depth intervals during nail insertion. In the Lottes group, much larger bursting strains were generated in the lateral cortex when using a distal starting point (P < 0.05). In the unreamed Russell-Taylor group, the anteromedial surface strains were significantly increased using a distal starting point (P < 0.05). The Grosse-Kempf group showed no significant difference in strains associated with any insertion point during tibial intramedullary nailing.

Adult↗
PubMed1997

Femoral insertion of the ACL. Radiographic quadrant method.

The optimal femoral insertion or footprint for an anterior cruciate ligament (ACL) graft is the anatomic site. This study was designed to determine the radiographic localization of the femoral insertion of the ACL on a lateral roentgenogram using a quadrant method. Ten human cadaveric knees with intact ACL were dissected. The most anterior, posterior, proximal, and distal borders of the femoral insertion of the ACL were marked with K-wires that were shortened at the bone level of the intercondylar fossa. A roentgenogram was obtained in the strictly lateral position. The end of the K-wires determined the projection of the femoral ACL insertion on the lateral roentgenogram. The center of the radiographically marked area was defined as point K, then four distances were measured on the lateral roentgenogram: distance t (representing the total sagittal diameter of the lateral condyle measured along Blumensaat's line), distance h (representing the maximum intercondylar notch height), distance a (representing the distance of point K from the most dorsal subchondral contour of the lateral femoral condyle), and distance b (representing the distance of point K from Blumensaat's line). Distance a is a partial distance of t and distance b is a partial distance of h, and distances a and b are expressed as length ratios of t and h. The center of the femoral insertion of the ACL was located at 24.8% of the distance t measured from the most posterior contour of the lateral femoral condyle and at 28.5% of the height h measured from Blumensaat's line. Based on these results, the ACL can be found just inferior to the most superoposterior quadrant, which means in anatomic terms it is localized from the dorsal border of the condyle at approximately a quarter of the whole sagittal diameter of the condyle and from the roof of the notch at approximately a quarter of the notch height. By using this radiographic quadrant method combined with fluoroscopic control during surgery, we were able to reinsert the ACL at its anatomic insertion site. This method is independent of variation in knee size or film-focus distance, easy to handle, and reproducible.

Anterior Cruciate Ligament↗
PubMed1997

Velamentous cord insertion in monochorionic twin gestation. An added risk factor.

OBJECTIVE: To study the effects of umbilical cord insertion combinations on outcomes in monochorionic (MC) twin placentas. STUDY DESIGN: Sixty consecutive MC placentas were analyzed by cord insertion patterns with regard to growth discordance, placental parenchymal sharing, types and patterns of intertwin vascular anastomoses, perinatal mortality and frequency of fetofetal transfusion. Cord insertions were classified as central/eccentric (CEN) or velamentous/marginal (VEL). RESULTS: Forty-five percent of the twins had VEL insertions. The CEN/VEL combination was found in 53% of pairs. The CEN/VEL group had the highest rates of growth discordance > 20%, unequal placental parenchymal sharing, uncompensated anastomoses and perinatal demise. CONCLUSION: VEL cord insertion and the CEN/VEL combination are indicators of high-risk subgroups within MC twins. VEL cord insertions can be diagnosed by ultrasound, identifying these high-risk groups.

Diseases in Twins↗