Assessment of deformation of the mitral valve complex during off-pump coronary artery bypass surgery using three-dimensional echocardiography in a porcine model.

BACKGROUND: This study aimed to assess the deformation of the mitral valve complex during the displacement of the beating heart by using three-dimensional echocardiography in a porcine off-pump coronary artery bypass grafting (OPCAB) model. METHODS: In nine healthy swine, we positioned the beating heart as an OPCAB model, i.e. control, left anterior descending artery (LAD), right coronary artery (RCA), and left circumflex artery (LCX) positions. In each position, three-dimensional echocardiography was performed to assess the mitral valve complex with hemodynamic parameters. We analyzed the deformation of the mitral valve and the three-dimensional coordinates of the papillary muscles. RESULTS: There was a significant increase in maximum tenting length and tenting volume (control 0.70±0.30, LAD 0.65±0.27, RCA 0.79±0.23, LCX 0.95±0.34cm3, p<0.05) in the LCX position compared with the other positions. The posterior papillary muscle (PPM) angle had a significant relationship with the tenting volume (r=-0.643, p<0.001). The PPM was displaced to the medial side in the LAD and LCX positions (p<0.01). CONCLUSIONS: The prime cause of the deformation of the mitral leaflets is suggested to be the displacement of the PPM associated with the change in geometry of the left ventricle in a porcine model.

Tactile sensor is useful for estimating liver hardness and liver fibrosis compared with ultrasonography and computed tomography.

BACKGROUND/AIMS: We examined whether conventional ultrasonography (US) and computed tomography (CT) were useful to evaluate liver hardness and hepatic fibrosis by comparing the results with those obtained by a tactile sensor using rats with liver fibrosis. METHODOLOGY: We used 44 Wistar rats in which liver fibrosis was induced by intraperitoneal administration of thioacetamide. The CT and US values of each liver were measured before laparotomy. After laparotomy, a tactile sensor was used to measure liver hardness. We prepared Azan stained sections of each excised liver specimen and calculated the degree of liver fibrosis (HFI: hepatic fibrosis index) by computed color image analysis. RESULTS: The stiffness values and HFI showed a positive correlation (r=0.690, p<0.001), as did the tactile values and HFI (r=0.709, p<0.001).In addition, the stiffness and tactile values correlated positively with each other (r=0.814, p<0.001). There was no correlation between the CT values and HFI, as well as no correlation between the US values and HFI. CONCLUSION: We confirmed that it was difficult to evaluate liver hardness and HFI by CT or US examination, and considered that, at present, a tactile sensor is useful method for evaluating HFI.

Effects of phenylephrine and noradrenaline on coronary artery motion in an open-chest porcine beating heart model.

PURPOSE: During off-pump coronary artery bypass (OPCAB), surgeons are required to perform a precise anastomosis on the beating heart. The hypotension caused by vertical displacement of the heart during OPCAB is usually treated with vasopressors, such as noradrenaline and phenylephrine. However, the effects of these agents on coronary artery motion are unknown. The present study analyzed the motion of the target coronary arteries during noradrenaline or phenylephrine infusion using three-dimensional motion capture and reconstruction technology. METHODS: The left anterior descending (LAD) artery, left circumflex (LCX) artery and right coronary artery (RCA) of 12 female landrace pigs (weight 50 ± 1 kg) were stabilized using a tissue stabilizer. The motions in the regions were captured before and during noradrenaline (n = 5) and phenylephrine (n = 7) infusion. RESULTS: Noradrenaline (0.15 µg/kg/min) and phenylephrine (1.1 µg/kg/min) significantly increased the blood pressure. Noradrenaline significantly increased the motion parameters, such as the distance moved, maximum velocity, acceleration and deceleration at the LAD (4.2 vs. 7.9 mm, P = 0.025; 95.7 vs. 215.5 mm/s, P = 0.0074; 35.3 vs. 83.6 m/s(2), P = 0.0096 and -35.6 vs. -83.6 m/s(2), P = 0.005, respectively). The values during phenylephrine infusion did not change except for the distance moved at the LAD (3.8 vs. 7.7 mm, P = 0.042). The motion parameters at the LCX and RCA during noradrenaline and phenylephrine infusion did not change significantly. CONCLUSIONS: The effect of phenylephrine on the coronary artery motion was less dramatic than that of noradrenaline.

Surface density mapping of natural tissue by a scanning haptic microscope (SHM).

To expand the performance capacity of the scanning haptic microscope (SHM) beyond surface mapping microscopy of elastic modulus or topography, surface density mapping of a natural tissue was performed by applying a measurement theory of SHM, in which a frequency change occurs upon contact of the sample surface with the SHM sensor - a microtactile sensor (MTS) that vibrates at a pre-determined constant oscillation frequency. This change was mainly stiffness-dependent at a low oscillation frequency and density-dependent at a high oscillation frequency. Two paragon examples with extremely different densities but similar macroscopic elastic moduli in the range of natural soft tissues were selected: one was agar hydrogels and the other silicon organogels with extremely low (less than 25 mg/cm(3)) and high densities (ca. 1300 mg/cm(3)), respectively. Measurements were performed in saline solution near the second-order resonance frequency, which led to the elastic modulus, and near the third-order resonance frequency. There was little difference in the frequency changes between the two resonance frequencies in agar gels. In contrast, in silicone gels, a large frequency change by MTS contact was observed near the third-order resonance frequency, indicating that the frequency change near the third-order resonance frequency reflected changes in both density and elastic modulus. Therefore, a density image of the canine aortic wall was subsequently obtained by subtracting the image observed near the second-order resonance frequency from that near the third-order resonance frequency. The elastin-rich region had a higher density than the collagen-rich region.

Softness sensor system for simultaneously measuring the mechanical properties of superficial skin layer and whole skin.

BACKGROUND/AIMS: Few attempts have been made to distinguish the softness of different skin layers, though specific measurement of the superficial layer would be useful for evaluating the emollient effect of cosmetics and for diagnosis of skin diseases. MATERIALS AND METHODS: We developed a sensor probe consisting of a piezoelectric tactile sensor and a load cell. To evaluate it, we firstly measured silicone rubber samples with different softness. Then, it was applied to human forearm skin before and after tape-stripping. A VapoMeter and skin-surface hygrometer were used to confirm removal of the stratum corneum. A Cutometer was used to obtain conventional softness data for comparison. RESULTS AND CONCLUSIONS: Both the piezoelectric tactile sensor and the load cell could measure the softness of silicone rubber samples, but the piezoelectric tactile sensor was more sensitive than the load cell when the reaction force of the measured sample was under 100 mN in response to a 2-mm indentation. For human skin in vivo, transepidermal water loss and skin conductance were significantly changed after tape-stripping, confirming removal of the stratum corneum. The piezoelectric tactile sensor detected a significant change after tape-stripping, whereas the load cell did not. Thus, the piezoelectric tactile sensor can detect changes of mechanical properties at the skin surface. The load cell data were in agreement with Cutometer measurements, which showed no change in representative skin elasticity parameters after tape-stripping. These results indicate that our sensor can simultaneously measure the mechanical properties of the superficial skin layer and whole skin.

Observation of local elastic distribution in aortic tissues under static strain condition by use of a scanning haptic microscope.

The purpose of this study was to observe variation in the local elastic distribution in aortic tissue walls under different static strain conditions, including physiological strain, by use of a scanning haptic microscope (SHM). Strain was applied by stretching aortic tissues in the circumferential direction by the simple tensile method or by the rod-insertion method to mimic in vivo internal pressure loading. SHM measurements in a saline solution at room temperature were performed on canine thoracic aorta using a glass needle probe with a diameter of ca 5 µm and a scanning area and point pitch of 160 × 80 µm and 2 µm, respectively. Under strain of 0-0.23, corresponding to internal pressure of 0-150 mmHg, wavy-shaped elastin fibers stretched until they were almost straightened, and the average elastic modulus increased almost linearly. Although there was little difference between the images obtained for the two different stretching methods, under high strain (>0.36; 250 mmHg) significant circumferential orientation of the collagen fibrils occurred with an increase in the average elastic modulus. It was concluded that the pressure resistance of the aorta under physiological strain was mainly afforded by elastin fibers; collagen fibrils contributed little except under much higher pressures.

Biomechanical properties and associated collagen composition in vaginal tissue of women with pelvic organ prolapse.

PURPOSE: The pelvic tissue of women with pelvic organ prolapse is stiffer than that of controls but there are scant data on the collagen composition that corresponds to these mechanical properties. We evaluated human vaginal wall stiffness using the novel scanning haptic microscope and correlated these measurements to collagen expression in women with and without pelvic organ prolapse. In this simultaneous biomechanical and biochemical assessment we evaluated the usefulness of this measurement technology for pelvic floor disorder research and confirmed an association between mechanical properties and composition. MATERIALS AND METHODS: The elastic constant (a measure of stiffness) of vaginal wall tissue was measured with the scanning haptic microscope. Protein expression of collagen types I and III of the same tissues were determined by Western blot. The Student t test was used for comparisons between groups. RESULTS: The anterior and posterior vaginal walls of premenopausal and postmenopausal women with pelvic organ prolapse were significantly stiffer than those of controls (p <0.05). Collagen III protein expression in the anterior vaginal wall in the control group was higher than in menopausal women. Collagen I expression was not significantly different between controls and cases. CONCLUSIONS: The scanning haptic microscope produced reliable mechanical measurements in small tissue samples without tissue destruction. Vaginal wall tissues are stiffer in women with pelvic organ prolapse than in controls. This vaginal wall stiffness was associated with lower protein expression of collagen III in the vaginal wall compared to that in asymptomatic controls.

Pyrrole-imidazole polyamide targeting transforming growth factor ß1 ameliorates encapsulating peritoneal sclerosis.

OBJECTIVE: Encapsulating peritoneal sclerosis (EPS) is a devastating fibrotic complication in patients treated with peritoneal dialysis (PD). Transforming growth factor ß1 (TGF-ß1) is a pivotal factor in the induction of EPS. METHODS: To develop pyrrole-imidazole (PI) polyamide, a novel gene silencer, targeted to the TGF-ß1 promoter (Polyamide) for EPS, we examined the effects of Polyamide on messenger RNA (mRNA) expression of TGF-ß1, vascular endothelial growth factor (VEGF), and extracellular matrix (ECM) in mesothelial cells in vitro, and on the thickness of injured peritoneum evaluated by histology and high-resolution regional elasticity mapping in rats in vivo. RESULTS: Polyamide significantly lowered mRNA expression of TGF-ß1 and ECM in vitro. Polyamide labeled with fluorescein isothiocyanate was taken up into the injured peritoneum and was strongly localized in the nuclei of most cells. Polyamide 1 mg was injected intraperitoneally 1 or 3 times in rats receiving a daily intraperitoneal injection of chlorhexidine gluconate and ethanol (CHX) for 14 days. Polyamide significantly suppressed peritoneal thickening and the abundance of TGF-ß1 and fibronectin mRNA, but did not affect expression of VEGF mRNA in the injured peritoneum. Elasticity distribution mapping showed that average elasticity was significantly lower in Polyamide-treated rats than in rats treated solely with CHX. CONCLUSIONS: Polyamide suppressed the stiffness, ECM formation, and thickening of the injured peritoneum that occurs during EPS pathogenesis. These data suggest that PI polyamide targeted to the TGF-ß1 promoter will be a specific and feasible therapeutic strategy for patients with EPS.

Landiolol reduces coronary artery motion in an open-chest porcine model: implications for off-pump coronary artery bypass surgery.

Reduction of target coronary artery motion is imperative for successful off-pump coronary artery bypass surgery. We hypothesized that landiolol, a novel ultra-short-acting selective ß-1 blocker, would reduce such coronary artery motion. To test this hypothesis, the motion of the left anterior descending artery of the porcine heart (n = 8) was analyzed by three-dimensional digital motion capture and reconstruction technology with or without continuous landiolol infusion. Landiolol (0.12 mg/kg/min) significantly decreased the heart rate (105 ± 16 vs. 90 ± 9 beats/min), three-dimensional distance moved (-20.4% vs. control), maximum velocity (-30.0% vs. control), acceleration (-31.1% vs. control), and deceleration (-28.6% vs. control) without inducing a significant change in the systolic blood pressure (85 ± 18 vs. 81 ± 22 mmHg), cardiac output (4.3 ± 1.4 vs. 4.1 ± 1.3 l/min), or pulmonary wedge pressure (7.8 ± 3.0 vs. 8.7 ± 2.9 mmHg). Landiolol reduces the heart rate and coronary artery motion with stable hemodynamics, which may facilitate performing precise anastomosis on the beating heart.

Variations in local elastic modulus along the length of the aorta as observed by use of a scanning haptic microscope (SHM).

Variations in microscopic elastic structures along the entire length of canine aorta were evaluated by use of a scanning haptic microscope (SHM). The total aorta from the aortic arch to the abdominal aorta was divided into 6 approximately equal segments. After embedding the aorta in agar, it was cut into horizontal circumferential segments to obtain disk-like agar portions containing ring-like samples of aorta with flat surfaces (thickness, approximately 1 mm). The elastic modulus and topography of the samples under no-load conditions were simultaneously measured along the entire thickness of the wall by SHM by using a probe with a diameter of 5 µm and a spatial resolution of 2 µm at a rate of 0.3 s/point. The elastic modulus of the wall was the highest on the side of the luminal surface and decreased gradually toward the adventitial side. This tendency was similar to that of the change in the elastin fiber content. During the evaluation of the mid-portion of each tunica media segment, the highest elastic modulus (40.8 ± 3.5 kPa) was identified at the thoracic section of the aorta that had the highest density of elastic fibers. Under no-load conditions, portions of the aorta with high elastin density have a high elastic modulus.

Simulation of vaginal wall biomechanical properties from pelvic floor closure forces map.

We simulated the way that pelvic floor muscles (PFM) generate zonal compression on the vagina and urethra in order to maintain urinary continence. Raw data were obtained using a probe to map the distribution of vaginal closure forces. Simulation model was made using ordinary Spring-mass model. The biomechanical properties are applied to the spring of the model. We simulated four models that are applied to asymptomatic subjects as controls and patients based on information obtained from the measured force maps using a vaginal probe. PFM values are measured when subjects are relaxed and during voluntary PFM contraction. Results show that simulation clearly distinguished between controls and patents and demonstrates that in the controls, after a period of 0.075 sec from the time when the rest force was added, the model was deformed to a neutral shape, and after another period of 0.075 sec from the time when the contract force was added at intervals of 0.001 sec, the closure force reaches maximum. The results render the simulation of the vaginal wall deformations that was obtained directly by the force maps. It shows that in controls the wall model is significantly deformed compared to that from the patient's model. In this research we simulated the response of the vaginal walls using spring mass model and the force maps of vaginal closure forces applied to control subjects and patients. The process of deformation of the vaginal wall is thus visualized demonstrating the relative pathologic differences between the two groups.

Stiffness mapping prostate biopsy samples using a tactile sensor.

Previous studies have demonstrated that the stiffness of cancerous cells reflects their pathological stage and progression rates, with increased cancerous cell stiffness associated with increased aggressiveness. Therefore, the elasticity of the cancerous cells has the potential to be used as an indicator of the cancer's aggressiveness. However, the sensitivity and resolution of current palpation and imaging techniques are not sufficient to detect small cancerous tissues. In previous studies, we developed a tactile-based device to map with high resolution the stiffness of a tissue section. The purpose of this study is to evaluate this device using different tissues (BPH, Cancer and PZ) collected from human prostates. The preliminary results show that the tactile device is sensitive enough to tell the differences of the stiffness of different tissues. The results also disclosed the factors (humidity, temperature and tissue degradation) which could dramatically affect the results of stiffness mapping. The tactile technology described in this paper has the potential to help disclose the underlying mechanical mechanisms that lead to increased stiffness in prostate tumors.

Surface elasticity imaging of vascular tissues in a liquid environment by a scanning haptic microscope.

The objective of this study was to make an elasticity distribution image of natural arteries in a liquid environment at high resolution at the micrometer level and at a wide area at the sub-square millimeter level by improving the scanning haptic microscope (SHM), developed previously for characterization of the stiffness of natural tissues. The circumferential sections (thickness, 1.0 mm) of small-caliber porcine arteries (approximately 3-mm diameter) were used as a sample. Measurement was performed by soaking a probe (diameter, 5 microm; spatial resolution, less than 2 microm) in saline solution at an appropriate depth. The vascular tissues were segregated by multi-layering a high elasticity region with mainly elastin (50.8 +/- 13.8 kPa) and a low one with mainly collagen and smooth muscle cells (17.0 +/- 9.0 kPa), as observed previously in high humidity conditions. The elasticity was measured repeatedly with little change for over 4 h in a liquid environment, which enabled observation with maintenance of high precision of a large area of at least 1,200 x 100 microm, whereas the elasticity was increased with time by the dehydration of samples with shrinkage in the air, in which an averaged elasticity in the overall area was approximately doubled within 2 h. This simple, inexpensive system allows observation of the distribution of the surface elasticity at the extracellular matrix level of vascular tissues in a liquid environment close to the natural one.

Selective beta-1 receptor blockade further reduces the mechanically stabilized target coronary artery motion during beating heart surgery.

OBJECTIVE: Adequate stabilization of anastomosis sites during off-pump coronary artery bypass is essential to obtain excellent graft patency. We examined the effect of beta-1 adrenergic receptor blockade on the target coronary artery motion by three-dimensional (3D) digital motion capture and reconstruction technology. METHODS: Eight pigs underwent a sternotomy. Reflection markers were attached to the surface coronary arteries, followed by a mechanical stabilizer application. Two high-speed digital cameras captured two-dimensional (2D) motion of the markers from different angles. These 2D data were reconstructed into 3D data points, representing the motion of each coronary artery. Landiolol hydrochloride, a novel selective beta-1 receptor blocker, was infused intravenously after acquisition of control data. RESULTS: Beta-1 receptor blockade decreased heart rate (105 ± 16 vs. 90 ± 9 beat/min; P = 0.007) without decreasing arterial blood pressure. The 3D distance moved (millimeter) during one cardiac cycle was significantly reduced on the left anterior descending (9.6 ± 2.8 vs. 6.6 ± 1.9 mm; P = 0.003), left circumflex (10.5 ± 6.3 vs. 6.4 ± 2.6 mm; P = 0.038), and right coronary (8.3 ± 3.6 vs. 6.5 ± 2.1 mm; P = 0.028) arteries. Reduction in the maximal velocity, maximal acceleration, and maximal deceleration of the anastomosis site in all coronary arteries was also found in a quantitative fashion. CONCLUSIONS: Selective beta-1 receptor blockade significantly reduces the 3D motion at anastomosis sites on the beating heart, with stable systemic blood pressure. Further quantitative investigations of pharmacological stabilization are warranted to achieve better outcome of the patients undergoing off-pump coronary artery bypass surgery.

Improvement of hydrogelation abilities and handling of photocurable gelatin-based crosslinking materials.

Three types of eosin-derivatized gelatins (eosin-gelatins) with different molecular weights (M(w)) of ca. 15 kDa (low-molecular-weight eosin-gelatin, LEG), ca. 30 kDa (medium-molecular-weight eosin-gelatin, MEG), and ca. 95 kDa (high-molecular-weight eosin-gelatin, HEG) were prepared. All the eosin-gelatins except for HEG dissolved completely in water at 37 degrees C within several hours even at high concentrations of 35 or 40 wt % along with polyamine (poly(N,N-dimethylaminopropylacrylamide)) to produce photo-crosslinkable materials. The materials had appropriate viscosity for in situ molding at 37 degrees C and could be handled as a liquid at low temperatures of up to 25 degrees C. Upon photoirradiation for several tens of seconds, the materials were converted almost completely to hydrogels in the desired form with a microporous network structure by the radical coupling reaction. The mechanical strength of the produced hydrogels could be controlled by selecting a particular molecular weight or concentration of eosin-gelatins. The hydrogels obtained from LEG (40 wt %) or MEG (35 wt %) had elasticity similar to that of goat periodontal tissue. The handling of the photo-crosslinkable materials at room temperature and their photogelation ability were drastically improved by reducing the M(w) of eosin-gelatin. The potential usefulness of the photo-crosslinkable materials to periodontal regeneration has been discussed.

Local elasticity imaging of vascular tissues using a tactile mapping system.

This study aimed to map the elasticity of a natural artery at the micron level by using a tactile mapping system (TMS) that was recently developed for characterization of the stiffness of tissue slices. The sample used was a circumferential section (thickness, approximately 1 mm) of a small-caliber porcine artery (diameter, approximately 3 mm). Elasticity was measured with a probe of diameter 1 microm and a spatial resolution of 2 microm at a rate of 0.3 s per point, without significant sample invasion. Topographical measurements were also performed simultaneously. Wavy regions of high elasticity, layered in the circumferential direction, were measured at the tunica media, which was identified as an elastin-rich region. The Young's modulus of the elastin-rich region in the media was 50.8 +/- 13.8 kPa, and that of the elastin-rich region of the lamina elastica interna was 69.0 +/- 12.8 kPa. Both these values were higher than the Young's modulus of the other regions in the media, including smooth muscle cells and collagen fibrils (17.0 +/- 9.0 kPa). TMS is simple and inexpensive to perform and allows observation of the distribution of the surface elastic modulus at the extracellular matrix level in vascular tissue. TMS is expected to be a powerful tool in evaluation of the maturation and degree of reconstruction in the development of tissue-engineered or artificial tissues and organs.

Tactile mapping system: a novel imaging technology for surface topography and elasticity of tissues or organs.

OBJECTIVE: : We demonstrated that the tactile mapping system (TMS) has a high degree of spatial precision in the distribution mapping of surface elasticity of tissues or organs. METHODS: : Samples used were a circumferential section of a small-caliber porcine artery (diameter: ∼3 mm) and an elasticity test pattern with a line and space configuration for the distribution mapping of elasticity, prepared by regional micropatterning of a 14-µm thick gelatin hydrogel coating on a polyurethane sheet. Surface topography and elasticity in normal saline were simultaneously investigated by TMS using a probe with a diameter of 5 or 12 µm, a spatial interval of 1 to 5 µm, and an indentation depth of 4 µm. RESULTS: : In the test pattern, a spatial resolution in TMS of <5 µm was acquired under water with a minimal probe diameter and spatial interval of the probe movement. TMS was used for the distribution mapping of surface elasticity in a flat, circumferential section (thickness: ∼0.5 mm) of a porcine artery, and the concentric layers of the vascular wall, including the collagen-rich and elastin-rich layers, could be clearly differentiated in terms of surface elasticity at the spatial resolution of <2 µm. CONCLUSIONS: : TMS is a simple and inexpensive technique for the distribution mapping of the surface elasticity in vascular tissues at the spatial resolution <2 µm. TMS has the ability to analyze a complex structure of the tissue samples under normal saline.

Influence of pelvic floor muscle contraction on the profile of vaginal closure pressure in continent and stress urinary incontinent women.

PURPOSE: We characterized the vaginal pressure profile as a representation of closure forces along the length and circumference of the vaginal wall. Vaginal pressure profile data were used to test the hypothesis that the strength of pelvic floor muscle contractions differs significantly between continent women and women with stress urinary incontinence. MATERIALS AND METHODS: Vaginal pressure profile recordings were made in 23 continent subjects and in 10 patients with stress urinary incontinence. The recordings characterized closure forces along the entire length of the vagina and identified differences among the anterior, posterior, left and right sides of the vaginal wall. Using a novel, directionally sensitive vaginal probe we made vaginal pressure profile measurements with the women at rest and during pelvic floor muscle contraction while supine. RESULTS: The nature of the vaginal pressure profile was characterized in terms of force distribution in the anterior and posterior vaginal walls, which was significantly greater than that on the left and right sides. The continent group had significant greater maximum pressure than the stress urinary incontinence group on the posterior side at rest (mean +/- SE 3.4 +/- 0.3 vs 2.01 +/- 0.36 N/cm(2)) and during pelvic floor muscle contraction (4.18 +/- 0.26 vs 2.25 +/- 0.41 N/cm(2)). The activity pressure difference between the posterior and anterior vaginal walls in the continent group was significantly increased when the pelvic floor muscles contracted vs that at rest (3.29 +/- 0.21 vs 2.45 +/- 0.26 N/cm(2)). However, the change observed in the stress urinary incontinence group was not significant (1.85 +/- 0.38 vs 1.35 +/- 0.27 N/cm(2)). CONCLUSIONS: The results demonstrate that the voluntary pelvic floor muscles impose significant closure forces along the vaginal wall of continent women but not in women with stress urinary incontinence. The implication of these findings is that extrinsic urethral closure pressure is insufficiently augmented by pelvic floor muscle contraction in women with stress urinary incontinence.

High resolution regional elasticity mapping of the human prostate.

What is it that the clinician "feels" during a digital rectal examination? To answer this question, it is necessary to measure the elastic properties of the prostate and verify the stiffness values with histological examination. Therefore, we devised an Elasticity Mapping System to evaluate the elastic properties of various histopathological grades of prostate cancer in relation to benign prostatic hyperplasia (BPH) and normal tissue. The system consists of a micro tactile sensor, a three-axis (XYZ) with one (fine Z) micromanipulation stage, a stereoscope camera and a measurement chamber. Using this methodology we mapped the elasticity of human prostate cancer (CaP) and it was obviously observed that the node was significantly harder than surrounding normal tissues and had some textures.

Spatial distribution of vaginal closure pressures of continent and stress urinary incontinent women.

Clinically the strength of the contraction of the female pelvic floor is qualitatively evaluated by vaginal tactile palpation. We therefore developed a probe to enable the quantitative evaluation of the closure pressures along the vagina. Four force sensors mounted on the four orthogonal directions of an intra-vaginal probe were used to measure the vaginal pressure profile (VPP) along the vaginal wall. Clinical experiments on 23 controls and 10 patients with stress urinary incontinence (SUI) were performed using the probe to test the hypothesis that the strength of pelvic floor muscle (PFM) contractions, imposed by voluntary contraction, is related to urinary continence. The results show that VPPs, characterized in terms of pressure distribution on the anterior and posterior vaginal walls, are significantly greater than those in the left and right vaginal walls. When the PFM contracted, the positions of the maximum posterior pressures in continent females and SUI patients were 0.63+/-0.15 cm and 1.19+/-0.2 cm proximal from their peak points of anterior pressure, which are 1.52+/-0.09 cm and 1.69+/-0.13 cm proximal from the introitus of vagina, respectively. The statistical analysis shows that the maximum posterior vaginal pressures of the controls were significantly greater than those of the SUI patients both at rest (continent: 3.4+/-0.3 N cm(-2), SUI: 2.01+/-0.36 N cm(-2), p<0.05) and during PFM contraction (continent: 4.18+/-0.26 N cm(-2), SUI: 2.25+/-0.41 N cm(-2), p<0.01). In addition, the difference between the posterior and anterior vaginal walls is significantly increased when the controls contract the PFM. By contrast, there are no significant differences in the SUI group. The results show that the VPP measured by the prototype probe can be used to quantitatively evaluate the strength of the PFM, which is a clinical index for the diagnosis or assessment of female SUI.