Role of coagulation factor XII in unexplained recurrent abortions in the Greek population.

OBJECTIVE: To investigate the prevalence and clinical significance of congenital factor XII (FXII) deficiency in the South-European Caucasian (Greek) population in a cohort of women with recurrent spontaneous abortions (RSAs). STUDY DESIGN: One hundred women with a history of > or =2 RSAs of unexplained nature were compared to 100 age-matched, healthy controls with no history of thrombotic disease or adverse pregnancy outcomes, regarding FXII activity. Women were included in the RSA group if they had normal coagulation parameters and no congenital or acquired thrombophilia. RESULTS: Fifteen of 100 women with RSA had reduced FXII activity, whereas all controls had normal FXII activity. FXII activity was significantly lower in the RSA than in the control group (median 100.5, range 10-150 vs. median 104.2, range 58.3-143.2, p < 0.016 by Mann-Whitney test). FXII activity was positively correlated with age in both the RSA and the control groups (r = +0.1, p = 0.04 and r = +0.04, p = 0.2, respectively), but this correlation reached statistical significance in the RSA group only. A negative correlation between FXII activity and the number of abortions in the RSA group was found (r = -0.2, p = 0.03). CONCLUSION: Congenital FXII deficiency is strongly associated with RSA in the Greek population.

Human amniotic fluid stimulates the proliferation of human fetal and adult skin fibroblasts: the roles of bFGF and PDGF and of the ERK and Akt signaling pathways.

Fetuses and adults follow different repair strategies for the healing of skin wounds. Experimental evidence indicates that this most probably reflects the intrinsic characteristics of fetal tissue, although environmental factors may also contribute to this phenomenon. Accordingly, the aim of the present study was to investigate the effect of the in utero environment, i.e., amniotic fluid, on one of the major parameters of wound healing, namely cell proliferation, and especially its effect on cultures of both human fetal and adult skin fibroblasts. We found that second trimester human amniotic fluid is a potent stimulant of DNA synthesis and proliferation of cells from both developmental stages. This effect is due to the presence of growth factors, especially basic fibroblast growth factor and platelet-derived growth factor, because inhibitors of their respective receptor kinases and specific neutralizing antibodies can significantly inhibit cell proliferation. Furthermore, we found that this mitogenic effect is mediated through the activation of the MEK/ERK and the PI3K/Akt signaling pathways. Interestingly, we have not observed any significant differences between fetal and adult fibroblasts in their response to amniotic fluid, indicating that cells from both developmental stages respond equally to this complex mixture of regulatory molecules.

Optimisation of T2 and M0 measurements of bi-exponential systems.

Cramer-Rao theory and computer simulations were used to show that the errors involved in calculating the magnetization and relaxation parameters of a two-component system decrease with: (1) increasing SNR, (2) increasing number of echoes used in the fitting procedure, and (3) increasing ratio of the relaxation times of the two components, T(22)/T(21). Images of bi-compartmental phantoms of known T(2) values were acquired using an optimized imaging sequence, and an optimized fitting algorithm was used to calculate the T(2) values of the two components by fitting the resulting images to a bi-exponential decay model. Accuracy better than 6% was achieved in the calculations of the T(2) values of the two components, and region fitting provided better accuracy than pixel-by-pixel fitting. The procedures were used to calculate the T(2) and M(0) values of equine carpal bones with known degree of radiographic bone sclerosis. Although the T(2) and M(0) values of both water and fat components all decreased with the degree of radiographic bone sclerosis, the transverse relaxation of the water component, T(2W), showed a greater decrease with advanced stages of bone sclerosis.

A novel RF coil configuration for in-vivo and ex-vivo imaging of arthritic rabbit knee joints.

The purpose of this study was to design and build an optimized Radio Frequency (RF) coil configuration, that would facilitate the acquisition of high resolution 3-dimensional (3D) images of arthritic and normal rabbit knees. A surface coil transmit surface coil receive configuration was built, in order to ensure adequate B(1) homogeneity over the imaging volume and maximum filling factor, and hence to maximize the Signal to Noise ratio (SNR) and resolution of the 3-dimensional images. The two coils were passively decoupled using crossed diodes and lambda/4 lines, both during the transmit and receive phases of the imaging experiment. A specialized animal bed, to optimize the use of the coils and minimize the experiment setup time was designed and constructed. Three dimensional images of resolution 156 x 156 x 468 microm, were acquired in 20 min; the results, in terms both of the high resolution images and the ease with which the experimental setup could be reproduced, demonstrated that this configuration is ideal for imaging rabbit knee joints.