Bull sperm selection by attachment to hyaluronic acid semi-interpenetrated hydrogels.

We report the development of a hydrogel-based approach to select bull spermatozoa, a crucial step for successful assisted reproductive techniques (ARTs). Hyaluronic acid (HA) semi-interpenetrated N-isopropylacrylamide (PNIPAM) co-20% N-Tris (hydroxymethyl) methyl acrylamide (HMA) hydrogels were synthetized on glass surfaces and cultured in presence of frozen-thawed bull spermatozoa. A fraction of motile bull spermatozoa population strongly attached to hydrogels and was partially released by treatment with hyaluronidase. Fifty-nine (59 ± 7.24) per cent of sperm cells attached to PNIPAM-HMA-HA hydrogels and 31.16 ± 4.81% of them were released upon treatment with medium containing hyaluronidase. This attached-released sperm fraction has acceptable characteristics of progressive motility (50.0 ± 5.0%), vigour (4), high viability (58.7 ± 11.7%) and low percentage of acrosome reacted spermatozoa (23.36 ± 4.1%). Our findings indicate that PNIPAM-HMA-HA hydrogels are non-toxic and allow the selection of high-quality sperm cells for ART.

Langmuir-Blodgett monolayers holding a wound healing active compound and its effect in cell culture. A model for the study of surface mediated drug delivery systems.

Langmuir and Langmuir-Blodgett films holding a synthetic bioinspired wound healing active compound were used as drug-delivery platforms. Palmitic acid Langmuir monolayers were able to incorporate 2-methyltriclisine, a synthetic Triclisine derivative that showed wound healing activity. The layers proved to be stable and the nanocomposites were transferred to solid substrates. Normal human lung cells (Medical Research Council cell strain 5, MRC-5) were grown over the monomolecular Langmuir-Blodgett films that acted as a drug reservoir and delivery system. The proliferation and migration of the cells were clearly affected by the presence of 2-methyltriclisine in the amphiphilic layers. The methodology is proposed as a simple and reliable model for the study of the effects of bioactive compounds over cellular cultures.

Formation of dendrimer-guest complexes as a strategy to increase the solubility of a phenazine N, N'-dioxide derivative with antitumor activity.

Poly(amidoamine) and Poly(propylenimine) dendrimers with different generations and peripheral groups were studied as solubility enhancers and nanocarriers for 7-bromo-2-hydroxy-phenazine N 5,N 10-dioxide. This compound possesses potential antitumoral and anti-trypanosomal activity, but its low solubility in physiological media precludes its possible application as therapeutic drug. The amino terminated dendrimers association with the active compounds as observed trough NMR studies showed that electrostatic interactions are essential in the solubilization enhancement process. The obtaining of a stable and no cytotoxic formulation makes the drug-carried association a suitable strategy for the generation of a drug delivery system for phenazine derivatives.

Formation and characterization of Langmuir and Langmuir-Blodgett films of Newkome-type dendrons in presence and absence of a therapeutic compound, for the development of surface mediated drug delivery systems.

Organic macromolecules with dendrimeric architectures are polymeric materials potentially useful as nanocarriers for therapeutic drugs. In this work, we evaluate a series of Newkome-type dendrons in Langmuir and Langmuir-Blodgett films as platforms capable of interacting with a potential antitumoral agent. The nanocomposite is proposed as model for the development of surface mediated drug delivery systems. We were successful in the formation and characterization of pure (dendrons) and composite (drug-dendron) stable and reproducible monolayers, and their transfer to solid substrates. A detailed study of topographic characteristics of the generated surfaces by atomic force microscopy was conducted. Furthermore, we probed dendron monolayer films as anchorage surfaces for mammalian cells. Normal cell attachment and proliferation on the surfaces were observed. No evident cytotoxic effects were detected, demonstrating the adequate biocompatibility of the surfaces.

[Molecular aspects of antineoplasic action of vitamin D]. / Aspectos moleculares de la accion antineoplasica de la vitamina D.

The effects of the environment, particularly dietary factors, may influence in the development and prevention of cancer. Vitamin D (colecalciferol) has been associated for years with calcium homeostasis regulation, but many epidemiological, biochemical and genetic studies reveal non classic effects of vitamin D, such as vitamin D involvement in the progression of different types of cancer. The aim of the present article was to give a review about the molecular mechanisms of the antineoplasic action of vitamin D. These effects are still not completely established, but it is well known that vitamin D induces cellular arrest, triggers apoptotic pathways, inhibits angiogenesis and alters cellular adhesion. To maintain suitable vitamin D levels seems to be necessary for many physiological processes, and not only for bone homeostasis. Clinical studies might determine vitamin D levels that can also protect against the cancer development.