Soft tissue elastometer

We have developed a device entitled the 'Tissue Elastometer' (TE) for evaluating the Young's modulus of soft tissues. Soft tissue specimens are compressed between the object plate of an electronic balance and a linearly actuated indenter with a small rounded tip. The hardware of the device was designed such that a deformation model for semi-infinite media is applicable for calculating the Young's modulus of test specimens from their collected force-displacement data. Force-elongation measurements were performed on long strips of cured silicone mixtures to produce calibrated, tissue-mimicking test samples for the TE in a Young's modulus range of 10-400 kPa. When tested with the TE, the Young's moduli of the silicone samples demonstrated accuracy to within 1-10% of their calibrated values. Testing on excised tissue samples (fresh store-bought poultry breast; bovine liver, kidneys, hind shanks; porcine) was also performed, and a repeatability of elasticity measurements was demonstrated in the range of 8-14%. Results indicate that the TE can be effectively used in laboratory and clinical environments to evaluate the elasticity modulus of tissues.     

Soft tissue tumours in childhood

The spectrum of soft tissue tumours in youg adults is very similar to that in more mature individuals, while those in childhood form a distinct group rarely seen outside the first decade. The majority of these are benign vascular or fibroblastic proliferations; in young children they may be highly cellular and mitotically active, but malignancy should be diagnosed with caution. Congenital soft tissue tumours constitute a special group in which the clinical outcome may be particularly difficult to predict from the histological appearances. This review focuses on those malignant soft tumours which are either peculiar to childhood or which manifest special features in childhood. Some recently recognized benign soft tissue tumours which occur mainly in childhood are also described. The fibromatoses are not discussed. As a guide to the appropriate treatment regime, the main histological distinctions to be drawn are between: 1 tumours of neuroectodermal origin (Ewing's sarcoma and primitive neuroectodermal tumour); 2 other sarcomas; and 3 the fibromatoses and other benign and potentially locally aggressive lesions requiring local excision. Immunohistochemical staining may be of considerable help in achieving the correct diagnosis, but it is vital that a panel of antibodies be applied and the results critically assessed. Cytogenetic analysis is also of growing importance, characteristic karyotypic abnormalities having been demonstrated in Ewing's sarcoma/primitive neuroectodermal tumour, alveolar rhabdomyosarcoma and synovial sarcoma.     

Soft tissue lipoleiomyoma.

A primary tumor composed of mature adipose tissue and smooth muscle occurring in the anterior abdominal wall of a 46 yr old Filipino woman is described. The tumor was not attached to the uterus, but had an appearance similar to a uterine lipoleiomyoma. It appeared as a soft, rubbery, encapsulated 11 cm ovoid mass with a uniform, white cut surface. Histologically, there were long intersecting bundles of bland smooth muscle mixed with nests of mature fat cells. The presence of differentiated smooth muscle was confirmed by fuchsinophilia, desmin positivity and electron microscopy. The patient also had 6 intramural leiomyomas, an area of adenomyosis, a subcutaneous lipoma of the subscapular region and chronic schistosomiasis of the appendix and left adnexa.     

Soft tissue myofibroblastomas.

Five well-circumscribed solitary soft tissue tumors composed of myofibroblasts are described and termed myofibroblastomas. By light microscopy these lesions are characterized by short, intersecting, or crisscrossing fascicles of spindle cells, sometimes associated with foci of necrosis and/or mitotic activity with less than three mitoses per 10 high power fields. Myofibroblastomas show well-defined myofibroblastic differentiation ultrastructurally with peripheral myofilaments and vimentin, actin, and desmin immunocytochemistry positivity. The five tumors described occurred in patients of various age groups, including one congenital, and in a variety of soft tissue locations. It is important to recognize this benign soft tissue neoplasm to avoid confusion with other soft tissue tumors and to separate this lesion from other myofibromatosis. This study elucidates the spectrum of light microscopic, ultrastructural, and immunocytochemistry findings of soft tissue myofibroblastomas and establishes this soft tissue tumor as a specific clinico-pathologic entity.     

Electrical properties of implant encapsulation tissue

The purpose of this study was to determine the electrical properties of the encapsulation tissue that surrounds electrodes chronically implanted in the body. Two four-electrode arrays, fabricated from either epoxy or silicone rubber, were implanted in each of six adult cats for 82 to 156 days.In vivo measurements of tissue resistivity using the four-electrode technique indicated that formation of the encapsulation tissue resulted in a significant increase in the resistivity of the tissue around the arrays.In vitro measurements of tissue impedance using a four-electrode cell indicated that the resistivity of the encapsulation tissue was a function of the tissue morphology. The tight layers of fibroblasts and collagen that formed around the silicone rubber arrays had a resistivity of 627±108 Ω-cm (mean ± SD; n=6), which was independent of frequency from 10 Hz to 100 kHz, and was significantly larger than the resistivity of the epoxy encapsulation tissue at all frequencies between 20 Hz and 100 kHz. The combination of macrophages, foreign body giant cells, loose collagen, and fibroblasts that formed around the epoxy arrays had a frequency-dependent resistivity that decreased from 454±123 Ω-cm (n=5) to 193±98 Ω-cm between 10 Hz and 1 kHz, and was independent of frequency between 1 kHz and 100 kHz, with a mean value of 195 ±88 Ω-cm. The results indicate that the resistivity of the encapsulation tissue is sufficient to alter the shape and magnitude of the electric field generated by chronically implanted electrodes.     

Modelling encapsulation tissue around cochlear implant electrodes

The objective of the study was to explore the effect of electrode encapsulation by fibrous scar tissue on electrical potential distributions and auditory nerve fibre excitation patterns. A finite element model in combination with an auditory nerve fibre model was used to predict changes in threshold currents and auditory nerve fibre excitation patterns. The model showed that electrical potentials at the target nerve fibres and the electrode contacts changed in the presence of encapsulation tissue. This led to changes in threshold currents and spread of excitation. The effect of electrode encapsulation on threshold currents and spread of excitation depended on the thickness of the perilymph layer separating the fibrous tissue encapsulation and the electrode array, nerve fibre survival status, electrode geometry and configuration, and array location. Model results suggested that arrays located close to the modiolus were most sensitive to threshold changes caused by electrode encapsulation (changes were between −0.26 and 2.41 dB), whereas encapsulation of an electrode array had less effect on threshold currents when the array was located in a lateral position in the scala tympani (changes were between −0.64 and 1.5 dB). For medially located arrays, changes in the spread of excitation varied between an increase of 0.21 mm and a decrease of 0.33 mm along the length of the basilar membrane, and an increase of 0.18 mm and a decrease of 0.66 mm along the length of the basilar membrane were calculated for laterally located arrays.     

背部软组织肿瘤

1.病例简介:患者男,68岁.发现背部肿块20年,起初为"黄豆"大小,2007年生长迅速,肿块逐渐增大,但无明显疼痛,触之较硬,活动度可,表面皮肤发红.在外院行肿块切除术,原单位初步诊断意见:"背部"软组织肿瘤,局部细胞生长活跃,良恶性及组织来源不能明确,建议上级医院会诊以明确诊断.     

Soft tissue calcification in chronic dialysis patients.

Autopsy protocols and microscopic slides of 56 dialyzed and 18 nondialyzed chronically uremic patients were reviewed to assess the presence, extent, and severity of extraosseous soft tissue calcification. Calcification was identified in 79% of the dialysis patients and 44% of the nondialysis patients (P iss less than .025). Soft tissue calcification most frequently involved the heart, lungs, stomach, and kidneys. Lesions were severe in 36% of the dialysis patients and, when strategically located within the myocardium, were life-threatening. The deaths of 6 dialysis patients were attributed to severe calcification of the cardiac conduction system and/or myocardium. The presence and severity of soft tissue calcification was not related to duration of dialysis, patients' age, degree of parathyroid gland hyperplasia, radiographic evidence of soft tissue calcification, serum calcium and phosphate levels, Ca X P products, or type or severity of metabolic bone disease.     

Regenerative dental medicine: stem cells and tissue engineering in dentistry.

The dawn of this century is brightened by the growing understanding and experimentation with stem cells as primary tools in the expanding regenerative medicine and tissue engineering revolution. The tradition of using prosthetic artificial implants to restore lost or damaged dental tissue will gradually be supplanted by more natural alternatives, including biological tooth replacement or induction. The practice of dentistry is likely to be revolutionized by biological therapies based on growth and differentiation factors that accelerate and/or induce a natural biological regeneration. This prospect has flourished from the gained knowledge provided by the molecular biological characterization of the genetic makeup of human cells and from a growing understanding of the effect of environmental factors. Prevention of dental diseases will also gain new ground as more insight is gained into the genetic makeup of microbial pathogens, their interactions with the host, and the host repair mechanisms. This review summarizes current knowledge, barriers, and challenges in the clinical use of stem cells with an emphasis on applications in dentistry.     

Soft tissue facial resemblance in families and syndrome-affected individuals

We investigated soft tissue facial resemblance among relatives with or without syndromes and among related and unrelated individuals diagnosed with the same syndrome. Using correlation coefficients, we compared facial landmark (i.e., three-dimensional coordinate) positions and measurements gained by photogrammetry in various combinations of normal and syndrome-affected individuals. There were fewer significant correlations for the three-dimensional coordinates and measurements between the normal parent-normal child pairs than for the normal sib pairs. There was no discernible pattern for the single measurements in the parent-child pairs, whereas all of the midline vertical measurements were significantly positively correlated in the normal sib pairs. Significant correlations were always positive in all sib comparisons, but ranged from negative to positive in all parent-child correlations. The shared environment of sibs was a possible explanation for their greater resemblance in comparison with parent-child pairs. We also had measurements from 11 subjects (related and unrelated) diagnosed with one of four syndromes, and we used these to compare individuals with the same syndrome by calculating correlation coefficients based on all available pairs of measurements. The highest significant positive correlations were found for related individuals with the same syndrome (0.72 to 0.83). Unrelated individuals with the same syndrome also had significant positive correlations, but they were lower (0.35 to 0.65). We therefore inferred that the genetic similarities between unrelated individuals with syndromes played a role in the resemblance between them, and that common genes and environment in related individuals further contributed to the high correlations found for them.