Multiple pathways of cell invasion are regulated by multiple families of serine proteases

The complex process of tumor invasion requires the coordinated expression and activity of cell-substratum adhesive interactions and of cell-associated protease systems, which destroy the extracellular matrix (ECM), in order to enable the invading cells to simultaneously grip and destroy the anatomical barriers that control cell spreading. A number of data indicate that such a `grip and go' process may be performed by an enlarging series of cell membrane-associated serine proteases and serine protease receptors, which provide the invasive cells with a functional unit (the protease and its receptor), able to mediate cell-substratum adhesion through specific receptor domains, to proteolytically degrade ECM and to deliver into the cell signals that up-regulate the expression either of the protease/receptor complex, or of other adhesion molecules, such as integrins. There is evidence that some proteases and protease receptor expression are under the control of tumor hypoxia, which is the result of an imbalance in oxygen supply and demand. The urokinase-type plasminogen activator (u-PA) receptor (u-PAR) is under hypoxic control and cooperates with other serine proteases of the blood coagulation pathways that may extravasate in the tumor milieu as a result of hypoxia-simulated increase of vessel permeability. Other serine proteases and their receptors cooperate with the cell-associated fibrinolytic system to promote cell invasion. Among these, tissue factor and its ligand coagulation factor VII, thrombin and its protease-activated receptors, and type II trans-membrane serine proteases seem to play a crucial role. This Review takes into consideration the complex scenario of the single serine proteases and related receptors that are involved in cell invasion, as well as the protease receptor/adhesion molecule interplay which is necessary to focus the cell surface-driven proteolysis where adhesion provides a grip to the invading cell. This revised version was published online in July 2006 with corrections to the Cover Date.     

Noninvasive method for measuring the electrical properties of deep tissues using an open-ended coaxial probe

A new noninvasive method of measuring the structure and the electrical properties of bilayered biological tissues was evaluated as a potentially useful diagnostic means for detecting changes in subcutaneous tissues. First, the input impedance of an open-ended coaxial probe radiating into a bilayered model was calculated using a full-wave method, the results showed that the evanescen higher order modes do not have a significant influence on the reflection coefficient of muscle layer surface. Then, it was clearly proven that the phase shift and the modulus of the reflection coefficient of muscle layer surface depending on the frequency are useful to estimate the thickness of fat layer and the electrical properties of muscle respectively. The experimental results showed an excellent agreement with the theoretical relationship between the phase shift and the thickness. The sensitivity of estimation of the electrical properties of muscle was shown to be not enough for differentiating between normal and diseased deep tissue because of noises from the experimental systems.     

A planar slab bidomain model for cardiac tissue

A fully three-dimensional model of the ventricular or atrial free wall will involve a planar geometry of finite thickness. The governing equations for the interstitial and extracellular potential of a planar slab of cardiac tissue comprised of parallel fibers undergoing uniform plane-wave activation are presented. A comparison with a bidomain of cylindrical geometry with the same half-thickness shows that the potentials in the planar bidomain (as a function of depth) approach core-conductor behavior more quickly.     

Extrapleural solitary fibrous tumor: clinicopathologic study of 17 cases and molecular analysis of the p53 pathway

Solitary fibrous tumor (SFT) occurring at various extrapleural sites is sometimes difficult to diagnose because of its histologic variability. Although a solitary fibrous tumor is usually a slow-growing tumor with favorable prognosis, a small number of malignant cases have been reported. In the present study, we examined the clinical behavior, histologic, immunohistochemical and molecular features of 17 cases of extrapleural SFT. Four tumors were located in the pelvic cavity, two in the nasal cavity, two were confined to the pulmonary parenchyma, and there was one each in the meninges, kidney, mediastinum, retroperitoneum, temporal region, neck, groin, buttock and thigh. Histologically, all the tumors were characterized by the presence of areas consisting of a proliferation of bland spindle cells with variable amounts of thick, often hyalinized or keloid-like intercellular collagen bundles. Highly cellular areas were observed in three tumors, frequent mitoses in two, and cellular pleomorphism and tumor necrosis in one each. All 17 tumors showed immunoreactivity to CD34 and 15 (88%) to bcl-2 protein. The labeling indices of p53, mdm2 protein and Ki-67 were generally low. PCR-SSCP and a subsequent sequence analysis of the p53 gene disclosed point mutation at codon 161 in exon 5 in one of the 13 cases analyzed. According to follow-up information, none of the patients had developed local recurrence or distant metastasis. Our results suggest that most extrapleural SFTs behave in a benign fashion even in a higher histologic grade group, and it is difficult to predict their clinical outcome. Complete surgical excision in order to obtain clear margins and long-term follow-up is advisable for patients with an extrapleural SFT.     

Juvenile hyaline fibromatosis: A report of two unrelated adult sibling cases and a literature review

Two unrelated adult sibling cases (36- and 32-year-old females) of Juvenile hyaline fibromatosis are presented. The parents of one of these patients were non-consanguineous but natives of a small Island, and one elder sister among four siblings was affected with the same disease. The parents of the other patient were consanguineous, and one other sibling suffered from the identical disease. Both patients presented with multiple subcutaneous nodules, which they had had since infancy, and had undergone numerous surgical excisions. Light microscopy examination of skin lesions from both patients showed identical histology; an abundance of a homogenous, amorphous, eosinophlllc extracellular matrix in which spindle-shaped cells were embedded. Electron microscopically, the spindle-shaped cells had hypertrophic Golgi apparatus and dilated, rough endoplasmlc reticulum. Fine flbrillar and granular material-filled structures, the contents of which were occasionally released into the extracellular matrix, were also seen, immunohistochemically, the spindle-shaped cells were vlmentin-positive but negative for α-smooth muscle actln and S-100 protein, and the hyaline ground substance was positive for type I and type III collagen but negative for type II and type IV collagen and tenascin. Matrix metalloprotelnase-1, -2, and -9, and tissue inhibitor of matrix metalloproteinase (TlMP)-2 was positive but TIMP-1 was negative. A review of 39 cases of juvenile hyaline fibromatosis In the literature is also presented. In summary, skin lesions may be the most outstanding symptoms of juvenile hyaline fibromatosis, but joint contracture and gingival hypertrophy precede the skin manifestation.     

骨组织工程种子细胞的研究进展

随着骨组织工程研究的进展 ,选择什么细胞作为其种子细胞成为近年来研究的热点。目前 ,骨组织工程应用中种子细胞有五种来源 :骨、骨膜、骨髓、骨外组织和早期胚胎。本文介绍了五种来源种子细胞的研究状况 ,并对种子细胞各自存在的问题及应用前景进行了分析。     

Endocrinology and paracrinology: Roles of growth factors during peri-implantation development

Several growth factor ligand and receptor gene products havebeen shown to play roles during preimplantation mammalian development.Genes for insulin-like growth factors (IGFs), transforming growthfactors (TGFs), fibroblast growth factor (FGF), platelet-derivedgrowth factor (PDGF) and receptors for insulin, IGF, PDGF, TGFand epidermal growth factor (EGF) are expressed by early embryosof several species including mouse, rat, cow and sheep. Rolesof growth factors during early development have been demonstratedby addition of purified growth factors to culture medium orby molecular genetic techniques that interfere with gene expression.In this way, it has been shown that successful development ofthe blastocyst is dependent on the action of epidermal growthfactor (EGF) and leukaemia inhibitory factor (LIF). Recent experimentsshow that both LIF and EGF stimulate secretion of urokinase-typeplasminogen activator (uPA) and gelatinase B/ matrix metalloproteinase-9(MMP-9) in day 7 mouse blastocyst outgrowths. At the same time,tissue inhibitors of MMPs (TIMPs) are also expressed by embryonic,decidual and uterine tissues during the implantation process.It appears that LIF may act directly or indirectly, by inducingthe expression of other cytokines, to regulate the temporaland spatial production and activity of proteases and proteaseinhibitors to create a favourable environment for implantation.     

The AMeX method: a multipurpose tissue-processing and paraffin-embedding method. III. Extraction and purification of RNA and application to slot-blot hybridization analysis.

RNA was extracted from tissues processed by a new fixation and paraffin-embedding method (the AMeX method) and examined by Northern blot analysis and slot-blot analysis. The RNA extraction method for AMeX-processed tissue sections after the deparaffinization step was the same as that for fresh materials. The total amount of cellular RNA extracted from AMeX-processed mouse liver tissue was slightly less than that extracted from fresh tissue. In tissues of malignant lymphoma, the total amount of cellular RNA extracted from 25 sections each 20 microns thick was about 1.6-1.8 micrograms/mm2, regardless of the histological subtype and period of storage. The extracted RNA was moderately degraded, and usually could not be used for Northern blot hybridization analysis. The intensity of ethidium bromide staining and the hybridization signals of RNA extracted from AMeX-processed tissues were usually reduced in comparison with RNA from fresh material, but specific signals could be detected by slot-blot hybridization analysis. We have demonstrated previously that the AMeX method preserves high-molecular-weight DNA and various antigens. Since the present study showed that information on mRNA can be obtained from AMeX-processed tissue, the versatility and usefulness of this method were further proven.     

Effect of iron on the surface, degradation and ion release properties of phosphate-based glass fibres

Phosphate-based glass fibres (PGF) have the unique characteristic of being completely soluble in an aqueous environment, releasing bioactive and biocompatible ions. They have been proposed as tissue engineering scaffolds for craniofacial skeletal muscle regeneration, where myoblasts are seeded directly onto the fibres. Studies have shown that these cells have a preference in their initial attachment to fibres of certain composition and size, which in turn control the rate of degradation. This study investigated the relationship between the surface properties, degradation properties and ion release (cationic and anionic species) by altering the chemical composition of the PGF. Iron oxide (Fe2O3) was incorporated into glasses containing P2O5 (50 mol%), CaO (30 mol%) and Na2O (20 mol%). Six glass compositions with Fe2O3 ranging from 0 to 5 mol% by replacing the equivalent Na2O mol% were investigated. Contact angle measurements showed that polar interactions occurring on the glass surfaces diminished with increasing Fe2O3 content. This behaviour was reflected in the estimated surface energies of the glasses, where the overall surface energy decreased with increasing Fe2O3 content due to the decrease in polar or acid/base component. The incorporation of up to 5 mol% Fe2O3 into PGF resulted in a significant reduction in the degradation rate (by two orders of magnitude), which can be related to the formation of more hydration resistant P-O-Fe bonds. However, the degradation rate increased with decreasing fibre diameter (comparing average diameters of 31.6 +/- 6.5 microm versus 13.1 +/- 1.3 microm) for a given mass of fibre, and this is related to the surface area to volume ratio. Taken together the results suggest that fibres with the larger diameters and containing 3-5 mol% Fe2O3 could initially be a more durable scaffold than ones with 1 or 2 mol% Fe2O3 for initial cell attachment.