Chitosan microparticles as injectable scaffolds for tissue engineering

The use of chitosan microparticles as injectable carriers for cell transplantation represents a promising alternative to avoid the drawbacks of the implantation of other forms of three-dimensional (3D) scaffolds seeded with cells. In this study, a 3D construct is obtained in vitro by combining chitosan microparticles crosslinked with genipin and goat bone marrow stromal cells (GBMCs). Cell viability and the morphology of GBMCs were evaluated after culture for 7 and 14 days. Our results show the feasibility of chitosan microparticles as potential injectable scaffolds for tissue engineering and regenerative medicine.Support from the Generalitat Valenciana through a short-term fellowship (No. BEFPI/2007/012) is kindly acknowledged. D.M.G.C. and J.L.G.R. acknowledge the support of the Spanish Ministry of Science through Project No. MAT2007-66759-C03-01 (including FEDER financial support). This work was also partially supported by the European Union-funded STREP Project HIPPOCRATES (NMP3-CT-2003-505758), and the European NoE EXPERTISSUES (NMP3-CT-2004-500283)

Ovarian stimulation protocols (anti-oestrogens, gonadotrophins with and without GnRH agonists/antagonists) for intrauterine insemination (IUI) in women with subfertility

Background Intrauterine insemination (IUI) combined with ovarian hyperstimulation (OH) has been demonstrated to be an effective form of treatment for subfertile couples. Several ovarian stimulation protocols combined with IUI have been proposed, but it is still not clear which stimulation protocol and which dose is the most cost-effective. Objectives To evaluate ovarian stimulation protocols for intrauterine insemination for all indications. Search strategy We searched for all publications which described randomised controlled trials comparing different ovarian stimulation protocols followed by IUI. We searched the Menstrual Disorders and Subfertility Group's Central register of Controlled Trials (CENTRAL). We searched the electronic databases of MEDLINE (January 1966 to present) and EMBASE (1980 to present). Selection criteria Randomised controlled trials only were considered for inclusion in this review. Trials comparing different ovarian stimulation protocols combined with IUI were selected and reviewed in detail. Data collection and analysis Two independent review authors independently assess trial quality and extracted data. Main results Forty three trials involving 3957 women were included. There were 11 comparisons in this review. Pregnancy rates are reported here since results of live birth rates were lacking. Seven studies (n = 556) were pooled comparing gonadotrophins with anti-oestrogens showing significant higher pregnancy rates with gonadotrophins (OR 1.8, 95% CI 1.2 to 2.7). Five studies (n = 313) compared anti-oestrogens with aromatase inhibitors reporting no significant difference (OR 1.2 95% CI 0.64 to 2.1). The same could be concluded comparing different types of gonadotrophins (9 studies included, n = 576). Four studies (n = 391) reported the effect of adding a GnRH agonist which did not improve pregnancy rates (OR 0.98 95% CI 0.6 to 1.6), although it resulted in significant higher multiple pregnancy rates (OR 2.9 95% CI 1.0 to 8). Data of three studies (n = 299) showed no convincing evidence of adding a GnRH antagonist to gonadotrophins (OR 1.5 95% CI 0.83 to 2.8). The results of two studies (n = 297) reported no evidence of benefit in doubling the dose of gonadotrophins (OR 1.2 95% 0.67 to 1.9) although the multiple pregnancy rates and OHSS rates were increased. For the remaining five comparisons only one or none studies were included. Authors' conclusions Robust evidence is lacking but based on the available results gonadotrophins might be the most effective drugs when IUI is combined with ovarian hyperstimulation. When gonadotrophins are applied it might be done on a daily basis. When gonadotrophins are used for ovarian stimulation low dose protocols are advised since pregnancy rates do not differ from pregnancy rates which result from high dose regimen, whereas the chances to encounter negative effects from ovarian stimulation such as multiples and OHSS are limited with low dose gonadotrophins. Further research is needed for each comparison made

Collecting and Maintaining Just-in-time statistics

Traditional DBMSs decouple statistics collection and query optimization both in space and time. Decoupling in time may lead to outdated statistics. Decoupling in space may cause statistics not to be available at the desired granularity needed to optimize a particular query, or some important statistics may not be available at all. Overall, this decoupling often leads to large cardinality estimation errors and, in consequence, to the selection of suboptimal plans for query execution. In this paper, we present JITS, a system for proactively collecting query-specific statistics during query compilation. The system employs a lightweight sensitivity analysis to choose which statistics to collect by making use of previously collected statistics and database activity patterns. The collected statistics are materialized and incrementally updated for later reuse. We present the basic concepts, architecture, and key features of JITS. We demonstrate its benefits through an extensive experimental study on a prototype inside the IBM DB2 engine