Primary osteoblasts response to shock wave therapy using different parameters

Over the past decade extracorporeal shock-wave therapy (ESWT) has been increasingly applied to orthopaedic and musculoskeletal pathologies, the aim of this study was to assess how the energy density of the shock waves and the number of impulses affect viability, differentiation and synthetic activity of osteoblasts. Primary sheep osteoblasts cultures were treated with ESWT with an electro-hydraulic shock wave generator by selecting three different energy levels (14-21-28 kV corresponding at 0.15-0.31-0.40 mJ/mm2) and two different total numbers of impulses (500, 1000) for each level. At the end of treatment, cell counts and viability were recorded. Cells were then cultivated for 48 hours starting from a concentration of 1 x 10(4) cells/ml. The biological activity and viability were evaluated at 24 and 48 hours after treatment. No cytodestructive effects were observed in Group A, while a cytodestructive effect of ESWT was seen in cultures receiving the highest energy treatments. The different shock wave treatment induced differences in MTT assays after 24 and 48 hours, in particular the highest level showed a detrimental effect on cell respiration at both experimental times as compared to the Control Group and the protein metabolism was generally depressed by ESWT with impulses at the highest energy level. After 24 hours such effect further increased with the growing number of impulses. The lowest energy level appeared to significantly improve the metabolic parameter in primary cell cultures as compared to controls when 500 impulses were selected. The current study has demonstrated that one of the most important aspects to be considered is not the total number of impulses used but the energy level of the shock waves, thus confirming that ESWT has a dose-dependent effect on cells.     

Modulation of Cytokeratin Expression in The Hamster Thymus: Evidence For a Plasticity of The Thymic Epithelium

Cytokeratin (CK) expression was investigated, by means of immunocytochemistry, in the hamster thymic epithelium during ontogeny, as well as in primary cultures and upon glucocorticoid hormone treatment in vivo. As compared to the distribution pattern of distinct monoclonal antibody-defined cytokeratins in the normal adult thymus, CK modulation was evidenced in the three situations studied. During thymus ontogeny, both cytokeratins of simple lining epithelia, as CK8 and CK18, as well as the CK1/CK10 pair (typical marker of terminal stage of keratinization), were expressed since early stages of thymus development. They were located in the central region of thymic lobules preceding the cortical-medullary distinctions. This differed from what had been previously shown for mouse thymus ontogeny, revealing that the interspecific diversity in the distribution pattern of thymic cytokeratins occurred early in fetal life. A modulation of CK expression was also detected when hamster thymic epithelial cells (TEC) were led to grow in culture, with a down-regulation of CK19 contrasting with an enhancement of CK18 expression. This diverged from the maintenance of the in situ pattern when human TEC were cultured. Last, in vivo hydrocortisone treatment, known to increase the numbers of KL1⁺ cells in the mouse thymus medulla, promoted a cortical expression of the CK1/CK10 pair in the hamster thymus. Taken together, our findings demonstrate a continuous plasticity of the thymic epithelium, at least regarding cytokeratin expression, and enlarge the concept of interspecific diversity of intrathymic CK distribution in conditions as morphogenesis, in vitro system, and responsiveness to glucocorticoid hormone treatment.     

Prenatal diagnosis of a complete mole coexisting with a dichorionic twin pregnancy: case report

A complete mole coexisting with dichorionic twins was diagnosed by the combined use of sonography and chorionic villus sampling at 10 weeks gestation. The pregnancy resulted in the death of one fetus at 31 weeks from presumed feto-maternal haemorrhage, while the other fetus survived in good condition. A summary of the available literature, combined with this report, reveals a total of seven pregnancies with twins and a coexistent complete mole. Only two out of 14 fetuses survived. Maternal complications included one case of pre-eclampsia and one persistent trophoblastic tumour. Accurate diagnosis of complete mole is possible by genetic analysis of chorionic villi obtained with standard transabdominal sampling. Twins with a coexistent complete mole will usually undergo miscarriage. However, fetal survival is possible and the maternal risks seem limited. A concomitance between gestational trophoblastic disease and the occurrence of feto-maternal haemorrhage is observed.     

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.     

Evolution of the influenza virus neuraminidase gene during drift of the N2 subtype

The complete genetic information for the neuraminidase (NA) gene of influenza virus A/Bangkok/1/79 has been cloned by in vitro synthesis of dsDNA, insertion into pBR322 plasmid, and transformation of Escherichia coli. The nucleotide sequence of the NA gene has been determined by the Maxam and Gilbert method. It is 1466 nucleotides long and contains a single open reading frame with a coding capacity for 469 amino acids. When compared to the NA genes of the N2 strains A/Victoria/3/75, A/Udorn/72, A/NT/60/68, and A/RI/5-/57, 90% of the nucleotide positions and 87% of the amino acid positions remained invariant. Forty-two nucleotide changes and 14 amino acid changes accumulated in the period 1975-1979, but the general structure of the protein appeared to remain constant.     

Characterization of a bovine collagen-hydroxyapatite composite scaffold for bone tissue engineering

Different biomaterials have been used as scaffolds for bone tissue engineering. Here we characterize a biomaterial composed of sintered (1100 degrees C) and powdered hydroxyapatite (HA) and type I collagen (Coll), both of bovine origin, designed for osteoconductive and osteoinductive scaffolds. Coll/HA proportions were 1/2.6 and 1/1 (wet weight), and particles sizes varied from 200 to 400 microm. Vv (volume density) and Sv (surface to volume density) for the HA particles in the composite ranged from 0.48 +/- 0.06 to 0.55 +/- 0.02 and 5.090 +/- 0.545 to 6.366 +/- 0.289 microm(-1), respectively. Due to the relatively small changes in Vv and Sv, a macroporosity could be characterized for the biocomposite. X-ray diffraction and infrared spectroscopy showed that the sintered bone was composed essentially of HA with minimum additional groups such as surface calcium hydroxide, surface and crystal water, free carbon dioxide and possibly brushite. Mass spectrometry detected carbonates at A and B sites of HA, and weakly bound to the structure. Human osteoblasts adhered and spread on both the HA particle surface and the collagen fibers, which seemed to guide cells between adjacent particles. The biocomposite studied has several characteristics considered as ideal for its use as a scaffold for osteoconduction and osteoinduction.