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Results for “Pliability”

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At least 19 recordsLinked to original sources

PubMed1994

[Pliability of vocal fold mucosa in relation to the location of subglottic mucosal upheaval during phonation].

Mucosal pliability was measured in 23 excised larynges, 19 canine and four human, at the three portions of the vocal fold, namely the midline, the anterior 1/4 and the posterior 1/4. The pliability at the midline showed a greater value than those at the other two portions. The free edge of the vocal fold showed a maximum pliability which gradually diminished toward the tracheal side and reached a minimum 3mm from the free edge of the fold. An increase in vocal fold tension resulted in lowering of mucosal pliability at all measured points and the point of minimal pliability shifted toward the oral side. The point of minimal pliability moved toward the tracheal side with direct electrical stimulation of the thyroarytenoid muscle (TA). Both pliability measurement and observation of mucosal vibration from the tracheal side using high speed cinematography or stroboscopy were performed on eleven of the excised canine larynges. The mucosal upheaval occurred at the point around which pliability was minimal. An increase in vocal fold tension resulted in an upward shift of the mucosal upheaval which occurred slightly below the point of minimal pliability. Electric stimulation of the TA resulted in a downward shift of the mucosal upheaval which occurred in accordance with the point of minimal pliability. Histological examination of the canine larynges revealed that the lamina propria became increasingly thin toward the point around which pliability was minimal and at which the mucosal upheaval occurred. At this point, the muscle layer approximated the epithelial layer with disappearance of the deep layer of the lamina propria. The point shifted to the oral side following an increment in vocal fold tension, while the point moved toward the tracheal side following contraction of the TA. Pliability of the vocal fold is minimal at the point around which the deep layer of the lamina propria disappears and the mucosal upheaval occurs.

Animals↗

PubMed1998

Pliability of the vocal fold mucosa in relation to the mucosal upheaval during phonation.

OBJECTIVES: To quantitatively evaluate the effect of vocal fold lengthening on pliability of the mucosa measured along the superior-inferior axis and to examine the relation of the location of mucosal upheaval (MU) during phonation to the changes in pliability pattern of the mucosa when the vocal fold was lengthened. DESIGN: Investigation of mechanical characteristics of the vocal fold in relation to the MU during phonation. MATERIALS: Five excised canine larynges. INTERVENTIONS: Vibrations with and without vocal fold lengthening were recorded from the tracheal side via high-speed photography or video recording combined with stroboscopic illumination. Tattooed marks on the lower surface of the vocal fold were used to locate the MU. Pliability was defined as the maximal distance elevated in response to a constant focal negative pressure. RESULTS: Pliability decreased significantly (P=.05) when the vocal fold was lengthened. The point of minimal pliability and MU without vocal fold lengthening were located slightly above the area where the muscular layer approached the epithelial layer. They were located closer to the free edge of the vocal fold when it was lengthened than when it was not. Discrepancy of their locations when the vocal fold was lengthened was suggested. CONCLUSIONS: The MU occurs around the point of minimal pliability when the vocal fold is not lengthened, whereas the MU occurs slightly more laterally than the point of minimal pliability when the vocal fold is lengthened. Although further study is necessary to explain this discrepancy, the presence of the sparse deep layer of the lamina propria seems to be essential in the generation of the mucosal wave.

Animals↗

PubMed1997

Quantitative evaluation of the effects of thyroarytenoid muscle activity upon pliability of vocal fold mucosa in an in vivo canine model.

Stiffness of the vocal fold is a significant factor in determining mucosal wave propagation and in the control of the fundamental frequency of phonation. We measured pliability of the vocal fold mucosa in an in vivo canine model as an index of stiffness while the histological layer-by-layer structure of the vocal fold was not disrupted. The point 1 mm below the free edge showed a maximal pliability that gradually diminished toward the tracheal side and reached a minimum. When the thyroarytenoid (TA) muscle contracted, pliability of the mucosa was significantly increased (P < 0.001). Mucosal pliability of the excised larynx was significantly increased compared with that in vivo (P < 0.001). The point of minimal pliability in the absence of TA muscle contraction did not shift after excision of the larynx, while TA muscle contraction caused a downward shift of the point of minimal pliability. Mucosal pliability can thus be used to quantitatively assess the effects of TA muscle contraction on stiffness of the vocal fold mucosa.

Animals↗

PubMed1989

Cusp pliability of the mitral valve: Doppler-echocardiographic and computer-tomographic study.

In order to study the mitral cusp pliability and calcification "in vivo" on the basis of the difference in the maximal and effective valve area, the Doppler-echocardiographic and computer tomographic method was used. The cusp pliability on the basis of the difference between the maximal and effective mitral valve area in absolute measures of cm2 was significantly smaller in patients with mitral stenosis, but in the deviations from normal indexed values of cusp pliability excluding the influence of the anatomic or maximal orifice area, there were no significant differences (normal values 0.00 +/- 27%). The normal relationship of the difference between the maximal and effective mitral valve area in absolute measures (y = cm2) and the maximal mitral valve area (x = cm2) is formulated with the regression equation: y = 0.317x - 0.245. The linear correlation of the normal mitral valve area and the stroke volume at rest in patients with the normal mitral valve is very tight. The stroke volume is significantly lower in mitral stenosis, and the time-velocity integral in the diastole or the mitral stroke distance was significantly greater. The relationship of the percentual deviation from the normal indexed values of cusp pliability excluding the influence of the anatomic or maximal orifice area, on the one hand, and the computer-tomographic approximation of calcium incrustation in mitral leaflets on the other are defined with a tight linear correlation. One could conclude that the magnitude of cusp pliability or calcification can be approximated by the Doppler-echocardiographic method.

Adult↗

PubMedDate not supplied

Tissue tonometry is a simple, objective measure for pliability of burn scar: is it reliable?

Objective measurement of burn scar response to treatment is important to facilitate individual patient care, research, and service development. This work examines the validity and reliability of the tonometer as a means of quantifying scar pliability. Ten burn survivors were recruited into the study. Triplicate measures were taken for each of four scar and one normal skin point. The pliability score from the Vancouver Scar Scale also was used as a comparison. The tonometer demonstrated a high degree of reliability (intraclass correlation coefficients 0.91-0.94). It also was shown to provide a valid measure of pliability by quantifying decreased tissue deformation for scar (2.04 +/- 0.45 mm) compared with normal tissue (3.02 +/- 0.92 mm; t = 4.28, P = .004) and a moderate correlation with Vancouver Scar Scale scores. The tissue tonometer provides a repeatable, objective index of burn scar pliability. Using the methods described, it is a simple, clinically useful technique for monitoring an individual's scar.

Adult↗

PubMed2005

Objective assessment of burn scar vascularity, erythema, pliability, thickness, and planimetry.

BACKGROUND: There is currently a lack of objective methods to assess scars. OBJECTIVES: The objectives of this study were to (1) determine the pattern of scar formation up to 24 months after a burn, compare clinical and photographic scar assessment, and determine what percentage of scars became hypertrophic after a major trauma and (2) replace each clinical parameter of a clinical scar scale by objective measurements. METHODS: Scars from 62 patients were evaluated from the acute phase up to 24 months after the burn, using photographs and clinical assessment during visits. Photographic planimetry helped estimate the percentage of scars that became hypertrophic. Thereafter, 69 patients had scars evaluated using clinical assessment and several instruments to evaluate pigmentation, erythema, pliability, thickness, and perfusion. The sensitivity and specificity of each instrument were determined regarding their ability to correlate with the parameters of hypertrophic and nonhypertrophic scars. Analysis of variance and Tukey's test were used in statistical analysis, with p<.05 indicating significance. RESULTS: Increased scar hypertrophy occurred between 6 and 12 months after the burn, and less than 30% of scars were hypertrophic at 18 to 24 months. Objective assessment of pliability and erythema, but not pigmentation, correlated significantly with clinical evaluation of hypertrophy. Hypertrophic scars had significantly higher perfusion than nonhypertrophic scars. A new scar rating system is proposed, based on the sensitivity and specificity of each instrument, to correlate with hypertrophic and nonhypertrophic scars. CONCLUSIONS: Objective rating systems using reliable instruments can be used to replace subjective scar assessment. Larger multicenter prospective studies should test this new scale in scars due to other mechanisms of injury.

Adolescent↗

PubMedDate not supplied

Assessment with the dermal torque meter of skin pliability after treatment of burns with cultured skin substitutes.

The assessment of visco-elastic (V-E) properties in cutaneous scars is critical to reduction of impairment and restoration of function after grafting of excised burns. Cultured skin substitutes (CSS) that consist of autologous keratinocytes and fibroblasts attached to biopolymer substrates are alternatives for permanent closure of excised, full-thickness burns, but assessment of scarring has been subjective. V-E properties of CSS were measured with a Dia-Stron Dermal Torque Meter (DTM 310, Dia-Stron, Ltd, Broomall, Pa), which applies a constant torque (10 mNm) for a fixed interval (10 seconds) and measures rotational deformation and recovery. Parameters of skin deformation were measured in patients (n = 10) after grafting of CSS or meshed skin autograft. Native human skin (NHS) of healthy volunteers (n = 13) served as the control. Skin healed after treatment with CSS or autograft was evaluated for 1 year or longer after grafting. Elastic stretch (Ue), viscous stretch (Uv), total extensibility (Uf), elastic recovery (Ur), total recovery (Ua), and residual plasticity (R) were measured as degrees of rotation, were tested for significance (P < .05) by Student t test comparisons between treatment groups and controls, and were subjected to regression analysis. Assessment of burn scar with the Dermal Torque Meter detected time-dependent increases of all individual parameters of V-E properties for both CSS and autograft during the first year after grafting. At 1 year or later, no statistical differences were found between CSS and autograft for individual parameters, but Ue and Ur for autograft were significantly lower than for NHS. At 1 year or longer, autograft was significantly different from CSS or NHS, with a greater ratio of Uv to Ue, and both graft types had a lower ratio of Ur to Uf than NHS had. These results suggest that instrumental measurement of scar pliability may increase objectivity in assessment of patient recovery and establish an absolute scale for quantitative analysis of V-E properties in skin after grafting of conventional or alternative skin substitutes.

Biocompatible Materials↗

PubMed2003

Centromeric chromatin pliability and memory at a human neocentromere.

We show that Trichostatin A (TSA)-induced partial histone hyperacetylation causes a unidirectional shift in the position of a previously defined binding domain for the centromere-specific histone H3 homologue CENP-A at a human neocentromere. The shift of approximately 320 kb is fully reversible when TSA is removed, but is accompanied by an apparent reduction in the density of CENP-A per unit length of genomic DNA at the neocentromere. TSA treatment also instigates a reversible abolition of a previously defined major domain of differentially delayed replication timing that was originally established at the neocentromeric site. None of these changes has any measurable deleterious effects on mitosis or neocentromere function. The data suggest pliability of centromeric chromatin in response to epigenetic triggers, and the non-essential nature of the regions of delayed replication for centromere function. Reversibility of the CENP-A-binding position and the predominant region of delayed replication timing following removal of TSA suggest strong memory at the original site of neocentromeric chromatin formation.

Acetylation↗

PubMed1995

Restoration of pliability to the mitral leaflets during reconstruction.

From July 1992 through February 1994, 34 patients have undergone a leaflet thinning procedure during reconstruction of the mitral valve. In this procedure a fibrous layer is separated from the atrial and/or ventricular surface of the anterior and posterior mitral leaflets. This reduces the thickness of the mitral leaflets and improves pliability and mobility. To our knowledge this procedure has not been reported previously.

Adolescent↗

PubMedDate not supplied