Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pliability”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed1991

Free muscle transfer with split thickness skin graft coverage in head and neck reconstructive surgery.

Sixteen patients (eight females and eight males) who underwent microsurgical free tissue transfers for head and neck reconstruction are reviewed. In this series, the flap reconstruction was completed on eleven patients with extra-oral defects and five with intra-oral defects. Split thickness skin graft coverage was used in all cases. The rectus abdominis free muscle flap was used in nine patients and the latissimus dorsi free muscle flap in seven patients. The choice of tissue reconstruction was decided by the size of the surgical defect. There were no failures of the tissue transfers and skin grafts. In skilled hands, free tissue transfer provides a reliable method of head and neck reconstruction, with a low incidence of recipient and donor site complications. In extra-oral defects, coverage of free muscle transfer with split thickness skin grafts, results in a better colour match than musculocutaneous flaps, and complements the appearance and pliability of the free muscle flap.

Adult↗
PubMed1991

[Transesophageal echocardiographic study on systolic flow pattern of the pulmonary vein in patients with mitral stenosis and atrial fibrillation].

To determine the clinical significance and effect of cycle length on systolic backward (C) and forward (S) flow patterns of the pulmonary vein, we performed transesophageal and transthoracic echocardiography in patients with atrial fibrillation (Af). Study population consisted of 10 patients with mitral stenosis and sinus rhythm (MS-SR), 15 with MS and Af (MS-Af), 15 with mitral valve replacement and Af (MVR-Af), 10 with Af without organic heart disease (lone-Af) and 15 normal subjects. Various parameters, including peak velocities of C and S waves, closing amplitude of anterior mitral valve echogram during end-diastole, amplitude of the mitral annulus and interatrial septal motion during systole and left atrial pressure during the mitral closing period or end-diastole, were measured in each group. Results were as follows: 1. C wave was observed in all Af groups and six of 10 patients with MS-SR. Particularly, peak velocity of the C wave in MS-Af group was increased significantly compared with those of every other group. 2. Peak velocity of S wave in all Af groups, particularly in MS- and MVR-Af groups, decreased significantly compared with that of the normal group. 3. There were significant negative correlations between preceding R-R interval and peak velocity of the C wave or closing amplitude of anterior mitral valve echogram or left atrial pressure during end-diastole in MS-Af group. 4. There were significant positive correlations between preceding R-R interval and peak velocity of the S wave or amplitude of the mitral annulus or interatrial septal motion during systole in MS-Af group. 5. Peak velocities of the C and S waves had no correlations to preceding R-R interval in lone-Af group. We concluded that the C and S waves of pulmonary venous flow velocity pattern in MS-Af are affected by cycle length, and that the former is influenced by left atrial pressure and/or pliability of the mitral valve during the mitral closing period, and the latter by the grade of left atrial dilatation and/or preceding left atrial emptying.

Adult↗
PubMed1991

[Development of severe mitral regurgitation following percutaneous transvenous mitral valve commissurotomy].

The purpose of this study was to analyze the risk factors of unexpected occurrence of mitral regurgitation (MR) following percutaneous transvenous mitral valve commissurotomy (PTMC) in patients with mitral stenosis. The analyzed factors were clinical pictures, hemodynamic findings, echocardiographic findings and balloon inflation techniques during PTMC. Among 24 patients undergoing successful PTMC using an Inoue's balloon, severe MR developed in five patients (21%). No significant correlation in the occurrence of MR was observed in clinical findings, hemodynamic data and balloon inflation techniques including the times and size of ballooning. Echocardiographic findings of the mitral valve including the pliability of the mitral leaflet and localized calcification of the mitral orifice were the most contributory factors to the occurrence of severe MR. The localized alternation of valve stiffness produced localized tear or excessive dilatation of the mitral leaflet during PTMC, resulting in severe MR. Hemodynamic results and calculated mitral valve areas after PTMC showed significant improvement in both groups with and without MR. However, symptomatic improvement in patients with severe MR was less prominent when compared to the patients without MR. Thus, the complete echocardiographic evaluation of the mitral valve apparatus before PTMC is important to prevent severe MR.

Aged↗
PubMed1991

[Gastrointestinal amyloidosis: differential diagnosis and indications for surgical therapy].

The diagnosis of gastrointestinal amyloidosis may be difficult for both the radiologist and the examining surgeon because clinical symptoms are often uncharacteristic. Upper gastrointestinal series may show stenosing submucosal masses in the esophagus or gastric antrum with diminished peristalsis and pliability mimicking malignancies. With small bowel involvement, diminished motility and segmental or complete distension, a prolonged transit time, and eventually obstruction are common findings. In the present study, we report four cases of gastrointestinal amyloidosis and review the indications for operative treatment. Surgery should be avoided for abdominal pseudo-obstruction and but may be indicated in patients with gastrointestinal bleeding, perforation or other severe complications. The postoperative course is characterized by impaired wound healing, a high rate of heart and kidney failures, and considerable perioperative mortality. Thus, results are frequently unsatisfactory.

Aged↗
PubMed1991

Vulvar reconstruction using a pedicle flap based on the superficial external pudendal artery.

We present a new method for vulvar reconstruction based on recently described vasculature of the lower abdominal skin and subcutaneous tissue. The superficial external pudendal artery supplies the region encompassing the suprapubic and infraumbilical skin. Thus, a pedicled skin flap based on the superficial external pudendal artery is designed in the suprapubic area and rotated into place for vulvar reconstruction. Because of the thickness and pliability of the flap as well as the inconspicuous donor scar, we believe this method of reconstruction to be superior to skin grafts or bulkier (ie, musculo- and fasciocutaneous) tissue flaps.

Adult↗
PubMedDate not supplied

A new bioprosthetic cardiac valve with reduced calcification.

A bioprosthetic cardiac valve cross-linked with a glycerol polyglycidyl ether polyepoxy compound (PC) was developed in order to reduce calcification and degeneration, which often occurs in bioprosthetic cardiac valves. Aortic valves harvested from dogs were treated with PC (PC valve). Right ventricle (RV)-pulmonary artery (PA) bypasses were placed in 12 dogs with PC-valved conduits, and the main PA was ligated. X-ray right ventriculography at 36 days (1 dog) and 37 days (1 dog) revealed an excellent open/close performance of the PC valve, and there was no visible thrombus in the valve. In our basic study, PC treated collagen gel disks implanted in the subcutaneous layer of growing rats showed remarkably less calcium deposition than did those treated with glutaraldehyde (GA). Biologic materials cross-linked with PC maintain their pliability, and become more hydrophilic and more hydrated than those cross-linked with GA. The hydrophilicity and hydration provide sufficient antithrombogenicity and a suitable environment for metabolism in the tissue fluid which contains oxygen, nutritive substances, and electrolytes, leading to inhibition of material degeneration. Therefore, PC valves are expected to show good valve function, sufficient antithrombogenicity, and excellent durability with less calcification, when compared to GA treated valves.

Animals↗
PubMed1990

[Echocardiographic aspects of developmental changes in ventricular function during acute myocardial infarct].

The development of ventricular function in the course of the first three weeks after acute myocardial infarction (AMI) was studied in the light of repeated examinations of 76 patients. Segmental derangement of mobility keeps increasing over the first postinfarction days in many patients, while the second and third week show a trend towards improvement. The derangements of segmental kinetics can be evaluated quantitatively by means of a computer or semi-quantitatively by subjective assessment. The former approach is suitable particularly in research work, the latter is fully satisfactory for routine practice. Concavity of the left ventricular wall was detected in 34.8% of the patients and in 56.5% of these the concavity appeared already on the first post AMI day. The organism responds in several ways to derangements of segmental mobility. First the sympathoadrenal activity is increased, which is echocardiographically reflected by hyperkinesia of the unaffected areas of the left ventricle. Further on segmental pliability decreases and the left ventricle becomes dilated by heterometric regulation. Reduced right ventricular function was recorded in 48.4% of patients with infarction of the lower wall and in 11.4% of patients with infarction of the anterior wall.

Adult↗
PubMed1990

Mechanical testing of cryopreserved aortic allografts. Comparison with xenografts and fresh tissue.

Reports indicate that cryopreserved aortic valve allografts have a better long-term survivability than other bioprostheses, such as the porcine xenograft. Unlike xenografts, allograft valves do not require treatment with glutaraldehyde and may therefore retain much of their original mechanical function. The effects of cryopreservation on the mechanical integrity of collagen fibers and mucopolysaccharides, however, are still largely unknown. We therefore compared the mechanical behavior of cryopreserved allograft leaflet material to that of fresh tissue and xenografts by measuring their bending stiffness (nine strips of tissue) and their uniaxial tensile stress/strain and stress/relaxation behavior (six strips of each tissue type). The bending tests showed no significant difference between the pliability of cryopreserved allografts and fresh pig aortic valve tissue, but the xenograft material was significantly stiffer than both (p less than 0.001). The mean circumferential tensile elastic moduli of the allografts, fresh tissue, and xenografts at a stress of 300 kPa were 9.1 +/- 5.4 MPa, 13.0 +/- 1.7 MPa, and 12.5 +/- 3.0 MPa, respectively, and were not significantly different from each other. We also found that the transition from a low to a high modulus on the stress/strain curves, a measure of extensibility, occurs at 23%, 22%, and 12% strain for the three materials. There was no significant difference between the allograft and the fresh tissues, but the xenograft material was less extensible than the other two (p less than 0.001). The xenograft tissue also had significantly lower rates of stress relaxation than the other two materials (p less than 0.005). Thus no detectable differences were found between the mechanical behavior of the cryopreserved allograft aortic leaflets and fresh tissue, whereas the xenograft material was less extensible and less capable of relaxing than both the allograft and fresh tissue. The ability of allografts valves to respond to tensile and flexural stresses in a manner similar to that of the natural aortic valve may therefore contribute to their good in vivo survivability.

Aorta↗
PubMed1990

[Reoperation of tetralogy of Fallot long after correction with aortic homograft: a case report].

Late results in the surgery for congenital heart disease repaired with external conduit have not yet been fully elucidated. We experienced a reoperation of tetralogy of Fallot (TF) that was previously repaired with an aortic homograft pretreated with beta-propiolactone for the reconstruction of right ventricular outflow tract. Ten years after correction of TF, right ventricular failure developed due to the regurgitation of tricuspid valve. At reoperation tricuspid annuloplasty was performed, and the valve of aortic homograft was also replaced with xenograft because of its uncertain durability. However, the resected valve had pliability with least degenerative change macroscopically. The postoperative course was smooth. The case was a rare one of late reoperation of TF due to the tricuspid valve regurgitation, and the case also indicated unexpected long durability of the valve cusp of the aortic homograft.

Adult↗
PubMed1987

Influence of negative supercoiling and of the proximity of left-handed Z-DNA on the Escherichia coli lactose repressor-operator interaction.

The influence of negative supercoiling and of flanking (dC-dG) tracts in either right-handed B- or left-handed Z-structures on the interaction of the Escherichia coli lac repressor was investigated. The operator was embodied within the lac control sequence, which was 95, 59, or 29 base pairs in length. Thus, the (dC-dG) regions (in either B- or Z-conformations) were at different distances from the repressor-binding site. Surprisingly, the presence of the promoter sequence (-59 to -20 relative to the +1 transcription start site) of the lac operator region increases the binding affinity of lactose repressor to the operator at high negative supercoil densities. This influence of the promoter region on the binding was abolished when the flanking (dC-dG) tracts were in the left-handed Z-DNA conformation. In contrast, minimal differences in the binding affinities were observed between plasmids containing shorter operator fragments (59 or 29 base pairs), whether the flanking (dC-dG) tracts were in right-handed B- or left-handed Z-forms. The promoter region may be directly involved in the repressor-operator complex in a previously unrecognized manner or may exert structural influence on the operator region. In general, increasing the amount of negative supercoiling increases the binding affinity and decreases the dissociation rate constants for the three operator-containing fragments, both with and without flanking Z-DNA tracts. Thus, the lac operator region possesses a previously unrecognized structural pliability, as influenced by negative supercoiling and neighboring sequences and/or conformations, which modulates its biological properties.

DNA, Superhelical↗
PubMed1987

Challenges in imperforate anus: II--Large rectovaginal defects: colonic vaginoanoplasty.

There are several infants and young children with a large recto vaginal fistula or common recto vaginal opening. This could arise either as a result of previous surgery, or entirely congenitally. Surgical correction in these difficult patients has been satisfactorily achieved in 11 patients using a modification of the Soave technique in which the upper rectum and colon are brought through a rectal sleeve and sutured to the perineum. The pliability of the vagina, and control of bowel movements and the cosmetic appearance following this procedure are good. The procedure is not very demanding technically.

Adolescent↗
PubMed1987

A model intraocular lens.

With so many different kinds of intraocular lenses from which to choose, the cataract surgeon is often faced with a difficult decision--which is the best lens for the patient. Although, there is no perfect intraocular lens, we attempt to delineate several desirable features. These include pliability, inert ultraviolet-filtering lens material, compact design, and posterior concavity to facilitate laser surgery. Successful blending of these features can make a well-tolerated intraocular lens.

Elasticity↗
PubMed1979

Expanded microporous polytetrafluoroethylene as a vascular substitute: a two year follow-up.

Since 1974, 131 femoropopliteal, distal popliteal, and tibial bypasses have been performed using expanded microporous polytetrafluoroethylene (PTFE). Forty patients were operated on for limb salvage, and 21 had had previous bypass procedures. The overall patency rate was 82%. Early occlusions possibly were related to technical error, but most probably were due to severity of disease and poor runoff. Late occlusions were related to progressive atherosclerosis in the proximal or distal arterial tree. A 75.7% cumulative patency rate was noted at 28 months. In man the PTFE prosthesis demonstrates a smooth intimal lining with fibroblastic ingrowth into the interstices of the graft. These results are considered to be excellent in this high-risk patient population. The patency rates achieved with PTFE are better than those accomplished with alternative conduits and approach the patency rates reported with autogenous saphenous vein. Expanded microporous polytetrafluoroethylene with its high patency, pliability, and tissue incorporation is an excellent arterial substitute. Only with continued use of this material and a more uniform patient selection can more equitable comparisons be made between expanded PTFE and the autogenous vein.

Adult↗
PubMed1986

Aortic valve insufficiency due to aortic dilatation: correction by sinus rim adjustment.

Idiopathic dilatation of the aortic root may commonly cause chronic insufficiency of the aortic valve. In these patients the cusp and sinuses are normal or virtually normal in area and pliability and the coronaries are not displaced. The insufficiency in these patients may be totally corrected by an adjustment of the intercommissural distance at the sinus rim level. The dilated ascending aorta is dealt with separately by whatever technique is appropriate. Five patients with aortic insufficiency due to idiopathic ascending aorta dilatation are described. All underwent successful correction of the insufficiency by adjustment of the intercommissural distance at the sinus rim level and thus far the correction has been maintained for up to 16 months after surgery in each.

Adult↗
PubMed1985

Mitral reconstruction.

Since 1968, the mitral valve was repaired, rather than replaced, in 647 patients. During the same period, 2,223 patients underwent prosthetic mitral replacement. Short and long-term results of mitral repair compare favorably with those after valve replacement. Five-year actuarial survival was 89% after closed commissurotomy (213 patients), 87% after open commissurotomy (203 patients) and 81% after more complex reconstructive procedures (231 patients). The operative risk was below 3% in all groups, the risk of reoperation was between 0.7% and 3%/patient year. Reconstruction was feasible in 16 patients with "floppy valve" syndrome, in 73 patients with ruptured chordae of the posterior leaflet and in 7 patients with bacterial endocarditis, with good long-term results in all of these patients. The feasibility of mitral reconstruction depends on the pliability of the anterior mitral leaflet, which may be decreased in mixed rheumatic lesions. In these patients, we would recommend prosthetic replacement of the valve. It is concluded that superior results may be achieved by mitral repair as compared to mitral replacement. However, indication and surgical technique largely depend upon the individual experience of the surgeon. The postoperative function of the reconstructed valve can be reliably assessed during the operation by left ventricular infusion of cold cardioplegic solution.

Adolescent↗
PubMed1985

[Effect of glutaraldehyde preservation on the immunogenic, physicomechanical and functional parameters of aortic valve xenograft bioprostheses].

It was shown that during conservation of heart valve xenograft bioprostheses, with glutaraldehyde (GA) the reagent penetrated the tissue from a 0.625% solution in a greater amount than from 0.25 and 1% solutions. The treatment with a 0.625% solution of GA essentially decreased the sensitizing and anaphylactic activity of the prosthetic tissue and contributed to the tissue inertness in radial immunodiffusion with antiserum of immunized animals. Subsequent treatment of the tissue with a 4% GA promoted a further decrease of immunogenic properties of the xenogeneic tissue. GA conservation increased durability and limited pliability, which led to a mild stenotic effect revealed during prosthesis functioning in vitro. The optimal method of the conservation of the aortal bioprosthesis consists in its 4-week treatment with 0.625% GA and a three-fold change of the solutions followed by storage of the tissue in 4% formaldehyde.

Anaphylaxis↗
PubMed1985

[Metabolism of purine compounds in skeletal muscle and blood and physical properties of the erythrocytes of mice with hereditary muscular dystrophy].

The authors studied the metabolism of purine compounds in the skeletal muscle of 129 Re mice with hereditary muscular dystrophy (MD). The study showed impairment of purine metabolism which was expressed in a sharp decrease in ATP levels and an increase in the content of AMP, IMP and uric acid. No changes were revealed in the pool of purine nucleotides in murine red blood cells. A study of some physical properties of the red blood cells in mice with myopathy showed no alterations in the osmotic resistance of erythrocytes, yet there was a reduction in their pliability as compared to control. Examination of the temperature resistance revealed anomalies of red blood cells in myodystrophic mice at 50 degrees C. The detected changes of some physical properties of erythrocytes seem to be related to abnormalities of the sumbembranous contractile apparatus of these cells.

Adenine Nucleotides↗
PubMed1985

[Current status of cardiac valve prosthesis].

Cardiac valve replacement has been clinically applied for the final therapeutic management of valvular heart disease for the last over 20 years. Cardiac valve prostheses are mainly divided into mechanical and biological valves. As mechanical valve, tilting disc valve or bi-leaflet center opening valve made of antithrombogenic and durable pyrolytic carbon are now widely used. As biological valve, porcine aortic valve or bovine pericardial valve treated with glutaraldehyde-tanning for maintenance of cusp durability and pliability are exclusively used at the present time. However, valve related complications such as thrombus formation, embolic event, infection, hemolysis and valve sound in mechanical valve and valve failure and infection in biological valve are unavoidable clinical problems. Therefore, the cardiac valve prostheses should be selected on the basis of patients medical, social and geographical conditions. It is still necessary to develop the ideal prosthesis without the late complications in connection with decision of optimum surgical timing, and technological improvement of materials and structural design.

Bioprosthesis↗