A roller scanning type prostate palpation sensor system using a cantilever beam type force measurement.

Palpation has been used for centuries in medicine as a screening and diagnosis modality for a number of pathological conditions. However, this technique is subjective since palpation sensitivity depends on the skill and experience of a medical examiner. An objective approach to acquire quantitative tactile information is needed. A roller scanning type palpation sensor system consisting of an x-axis linear slider and a palpation probe for detecting lumps in a soft object such as the prostate tissue is proposed and fabricated in this study. By translating the slider and changing the palpation angle of the probe, a chrome steel ball which was the contact component indented and scanned the surface of soft silicone phantoms embedded with hard lumps. Lumps were detected by measuring reaction force waveform fluctuations. Fundamental characteristics of the proposed sensor system were validated by comparison with the ground truth load cell output and showed a strong linear correlation with r2=0.9985. On silicone samples with hard lumps, the system was able to detect lumps of various sizes embedded at the depth of 5mm. From the results, the proposed sensor system holds potential for tissue characterization.

A cable driven robotic palpation system with contact force sensing based on cable tension observation.

BACKGROUND: Prostate Cancer screening based on manual palpation is subjective. Robotic palpation systems can objectively acquire stiffness conditions of the prostate. METHODS: A 2DoF cable driven robotic system for prostate palpation is proposed. An indirect method to estimate the contact force based on cable tension observation is presented. Kinematic models and a joint angle estimation method to determine the tip position of the probe are derived. Positioning accuracy was verified using an optical marker tracking system and by displacement measurement, respectively. The contact force estimation method was validated on silicone phantom samples. RESULTS: A good consistence between the estimated and measured contact force was observed. The contact force was correlated with the elastic modulus of each silicone phantom. There was also a good agreement between the theoretical and the measured tip position. CONCLUSION: In the proposed palpation system, the indirect contact force estimation method is viable and holds potential for the stiffness assessment of the prostate. The tip position vital for palpation can be determined through estimated joint angles.

Development of a tendon driven robotic probe for prostate palpation.

Palpation is a clinical diagnosis method utilized by physicians to acquire valuable information about the pathological condition of an organ using the sense of touch. This method, however, is subjective. The accuracy depends on the physician's experience and skill. Therefore, to make palpation objective and minimize variability in prostate cancer diagnosis among physicians, an automated palpation system is required. This paper describes the design and experimental evaluation of a 2 Degrees of Freedom (2DoF) tendon driven robotic palpation probe. The probe's palpation motion is controlled by actuating driving tendons using a cable-differential pulley transmission system and a return spring. A kinematic model of the robotic probe was derived. Furthermore, a tendon path length model was geometrically determined, and an optimization method for guide arc center placement to minimize change in tendon length was presented. Preliminary experimental and theoretical results were compared to determine the positioning accuracy. The difference between theoretical pitch angles [0°,80°] and measured values for the yaw angle range of [0°, 40°] was found to be in the range of 0.03° ~ 5.06°.Clinical Relevance- Diagnosis based on manual palpation is often subjective and palpation sensitivity depends on the physician's level of experience and skill. Therefore, an objective method for acquiring tactile information is relevant. Robotic palpation system provides objective and quantitative information for better understanding of the pathological and physiological changes in the tissue using mechanical properties as biomarkers.

Position of compression garment around the knee affects healthy adults' knee joint position sense acuity.

Athletes use compression garments (CGs) to improve sport performance, accelerate rehabilitation from knee injuries or to enhance joint position sense (JPS). The position of CGs around the knee may affect knee JPS but the data is inconsistent. The purpose of the present study was to determine the effects of CG position on healthy adults' knee joint position sense acuity. In a counterbalanced, single-blinded study, 16 healthy young adults (8 female, age: 25.5 y) performed an active knee joint position-matching task with and without (CON) a below-knee (BK), above-knee (AK), or whole-knee (WK) CG in a randomized order on the dominant (CompDom) or the non-dominant leg (CompNon-Dom). We also determined the magnitude of tissue compression by measuring anatomical thigh and calf cross sectional area (CSA) in standing using magnetic resonance imaging (MRI). Subjects had less absolute repositioning error (magnitude of error) in BK compared with CON condition. On the other hand, the analysis of the direction of error (constant error) revealed that in each condition subjects tended to underestimate the target position (AK, BK and CON: 75%; WK: 94%). In WK condition there was a significantly larger negative error (-2.7 ±â€¯3.4) as compared with CON (-1.6 ±â€¯3.7) condition. There also was less variable error, in WK compared to BK and CON conditions, indicating less variability in their position sense using a WK CG, regardless of the underestimation. CG reduced thigh CSA by 4.5 cm2 or 3% and calf CSA by Δ1.3 cm2 or 1%. The position of CG relative to the knee modifies knee JPS. The findings helps us better understand how the application of a WK CG may support athletic activities.

Passive mechanical properties of large intestine under in vivo and in vitro compression.

This paper presents experimental data obtained from both in vivo and in vitro compression of the large intestine of goat. In vivo experimental data were obtained from compression tests on the large intestine of an anesthetized goat using force-displacement acquisition equipment. In vitro experimental data were also obtained from tissue excised after the in vivo experiments, and two types of data were then compared. The results demonstrated that the stress values had a strong dependence on the compressive rate in the in vivo experiments, although such effect was not distinct in the in vitro experiments. Additionally, at a lower compression rate, the intestinal tissues were found to be stiffer in the in vitro experiments than in the in vivo ones. This paper is a preliminary report on the mechanical properties of the large intestine based on in vivo and in vitro experimental data.

Preclinical development of SMA artificial anal sphincters.

This article presents some progress in the development for preclinical trials of an artificial anal sphincter using shape memory alloys. The novel device has been proposed and developed by the author's group at Tohoku University. It has two dominant features different from other systems, which are either clinically available or still under development. One is that a solid driving element, a combination of shape memory alloy (SMA) ribbons and silicone elastomer sheets with a layered structure, is adopted for the opening and closing functions of the artificial sphincter. The other is a sandwich mechanism for the closing of bowel to reduce the risk of buckling induced ischemia which has been reported in hydraulically driven artificial sphincters with a radial squeezing mechanism. The device has fewer parts inside the body and therefore be implanted more easily. A new design eliminating the risk of heat burns enables long-term implantation and brings the device closer to practical use. Functionality and safety of the device have been proved in three-month animal experiments.

The possibility of muscle tissue reconstruction using shape memory alloys.

Severe dysfunction of muscle tissues can be treated by transplantation but the success rate is still not high enough. One possibility instead is to replace the dysfunctional muscle with artificial muscles. This article introduces a unique approach using shape memory alloys (SMAs) to replace the anal sphincter muscle for solving the problem of fecal incontinence. The use of SMAs that exhibit a two-way shape memory effect allows the device to function like a sphincter muscle and facilitates simple design. In this article, we will give a brief introduction to the functional material-SMA-together with its medical applications, and will follow this with a description of the recent progress in research and development of an SMA-based artificial sphincter. The possibility of its commercialization will also be discussed.

p51/p63 Controls subunit alpha3 of the major epidermis integrin anchoring the stem cells to the niche.

p51/p63, a member of the tumor suppressor p53 gene family, is crucial for skin development. We describe here identification of ITGA3 encoding integrin alpha(3) as a target of its trans-activating function, proposing that p51/p63 allows epidermal stem cells to express laminin receptor alpha(3)beta(1) for anchorage to the basement membrane. When activated by genotoxic stress or overexpressed ectopically in non-adherent cells, p51/p63 transduced a phenotype to attach to extracellular matrices, which was accompanied by expression of ITGA3. Motifs matching the p53-binding consensus sequence were located in a scattered form in intron 1 of human ITGA3, and served as p51/p63-responsive elements in reporter assays. In addition to the trans-activating ability of the TA isoform, we detected a positive effect of the DeltaN isoform on ITGA3. The high level alpha(3) production in human keratinocyte stem cells diminished upon elimination of p51/p63 by small interfering RNA or by Ca(2+)-induced differentiation. Furthermore, a chromatin immunoprecipitation experiment indicated a physical interaction of p51/p63 with intron 1 of ITGA3. This study provides a molecular basis for the standing hypothesis that p51/p63 is essential for epidermal-mesenchymal interactions.

Functional evaluation of an artificial anal sphincter using shape memory alloys.

This article describes an implantable artificial anal sphincter using shape memory alloys and its in vivo assessment in porcine models. The new design was developed as a low invasive prosthesis with a simple structure to solve the problem of severe fecal incontinence in patients with hypoplastic sphincters or without anal sphincters and especially for ostomates. The artificial anal sphincter consists of two shape memory alloy (SMA) plates as the main functional parts to perform two basic functions when the SMA artificial sphincter is fitted around intestines (i.e., an occlusion at body temperature and an opening function on heating). Our previous assessments with short-term animal experiments revealed promising properties with the occlusion function of the device, although some complications, such as overpressure induced ischemia, heat burn, and infections, remained. This article addresses the concerns related to the practical use of the device, the power supplement to drive the actuator, and overheating protection of the device inside bodies. Results of chronic animal experiments of up to 4 weeks suggested great potential for the improved device.

Evolutionarily conserved expression pattern and trans-regulating activity of Xenopus p51/p63.

p51/p63, a member of the p53 gene family, is structurally conserved among a wide range of organisms, although the transactivator (TA) and N-terminally truncated (deltaN) isotype producing property seems to vary. Since p51/p63 is thought to play important roles in skin, limb, and craniofacial development in mammals, we examined Xenopus laevis larval and adult tissues for expression of p51/p63. Temporal analyses indicated enhanced transcription of the deltaN form of p51/p63 in premetamorphosis phase (at stage 44-48). p51/p63-positive cells in the inner layer of larval skin expanded to the suprabasal layers during the stratification. The epithelium of limb buds and the maxillofacial ectodermal tissues in tadpoles had a high level expression of p51/p63. The cloned deltaN-A/gamma type Xenopus p51/p63 exhibited a dominant-negative activity against the human TA-A/gamma isotype in a reporter assay. These results suggest that tissue-specific p51/p63-inducing mechanism and isotype-specific transcriptional regulator activities of p51/p63 are conserved between mammals and frogs.

Development of an implantable artificial anal sphincter using a shape memory alloy.

BACKGROUND/PURPOSE: The authors created a new artificial anal sphincter using a shape memory alloy (AS-SMA) to treat fecal incontinence and evaluated its validity. METHODS: AS-SMA consists of 2 Ti-Ni plates to sandwich the intestine and generates a pressure of 55 mm Hg at its resting position. With the electric power supply, the 2 metals bend to form an almondlike shape making a maximum gap of 33 mm between each other at the temperature of 55 degrees C. The device was attached to the colostomy in a piglet and was operated several times a day for 1 month. Fecal continence, bowel movements, and general condition of the piglet were recorded. After the experiment, tissue damage around the device was investigated. RESULTS: Fecal continence was obtained while the device was in the resting position. When it was operated, bowel movements were observed. The bowel movements to operations ratio was 82:105 (78%). During the experiment, the animal had neither abdominal distension nor vomiting. At the autopsy, there was mild inflammation and shallow burns around the device. No compression injury was detected. CONCLUSIONS: AS-SMA achieved fecal continence of the colostomy. With reduction of the associated side effects, it would be a potential substitute for an impaired anal sphincter.