Label-free magnetic resonance imaging to locate live cells in three-dimensional porous scaffolds.

Porous scaffolds are widely tested materials used for various purposes in tissue engineering. A critical feature of a porous scaffold is its ability to allow cell migration and growth on its inner surface. Up to now, there has not been a method to locate live cells deep inside a material, or in an entire structure, using real-time imaging and a non-destructive technique. Herein, we seek to demonstrate the feasibility of the magnetic resonance imaging (MRI) technique as a method to detect and locate in vitro non-labelled live cells in an entire porous material. Our results show that the use of optimized MRI parameters (4.7 T; repetition time = 3000 ms; echo time = 20 ms; resolution 39 × 39 µm) makes it possible to obtain images of the scaffold structure and to locate live non-labelled cells in the entire material, with a signal intensity higher than that obtained in the culture medium. In the current study, cells are visualized and located in different kinds of porous scaffolds. Moreover, further development of this MRI method might be useful in several three-dimensional biomaterial tests such as cell distribution studies, routine qualitative testing methods and in situ monitoring of cells inside scaffolds.

Incidence and development of the human supracochlear cartilage.

The supracochlear cartilage is known as an accessory cartilage of the chondrocranium situated between the otic capsule and the trigeminal ganglion. Although claimed to appear regularly during human development, its incidence and development have been reported only scarcely in the literature. The aim of this study was to describe the position and relationships of the supracochlear cartilage during its development. This study was made in 96 human specimens of 7-17 weeks of development, belonging to a collection of the Embryology Institute of Complutense University of Madrid. In addition, three-dimensional reconstruction of the supracochlear cartilage was made from 1 specimen. This cartilage, spherical in shape, appeared bilaterally in 23 specimens and unilaterally (left side) in 5. In our results, the supracochlear cartilage was found in 26.5% of the cases and was related to the trigeminal ganglion, the dura mater of the trigeminal cavity and the otic capsule. In 4 specimens, bilaterally, the supracochlear cartilage was continuous with the otic capsule. This work suggests that, based on the structures to which the supracochlear cartilage is related, it could be derived from the cranial neural crest.

Embryonic anastomosis between hypoglossal nerves.

This article presents two cases of anastomosis of hypoglossal nerves in the suprahyoid region in human embryos of CR length 10.75 and 17.5 mm. This variation was studied in two human specimens at this stage of development and compared with the normal arrangement of the hypoglossal nerves in embryos at the same stage. The anastomotic branches were of similar caliber to the main trunks. In both cases the anastomosis was located dorsal to the origin of the geniohyoid muscles and caudal to the genioglossus muscles, lying transversally over the cranial face of the body of the hyoid bone anlage. The anastomosis formed a suprahyoid nerve chiasm on the midline in the embryo of 10.75 mm CR length.

Anatomical relationships of the cleidoatlanticus muscle. Interpretation about its origin.

An unusual muscular variation, the cleidoatlanticus muscle, was observed on the right-hand side of the lateral cervical region. The upper third of the muscle was concealed by the sternocleidomastoid muscle. There was a loop of nerves surrounding the muscle, formed by an anastomosis between the transverse cervical nerve and the greater auricular nerve. A fine vascular-nervous pedicle (formed by a small branch from the transverse cervical artery and by a branch from the medial supraclavicular nerve) entered the deep surface of the muscle at the junction of its middle and lower thirds. Taking into account the relationships that presented with the superficial branches of the cervical plexus, we consider that the cleidoatlanticus muscle is derived from the sternocleidomastoid muscle.

Use of rhBMP-2 activated chitosan films to improve osseointegration.

Considering the design and development of biomaterials used in tissue engineering, not only is it important that they are biocompatible but also that they induce the desired cellular response for tissue regeneration. Chitosan, a biocompatible and bioresorbable polymer of N-acetylglucosamine and glucosamine is used in our work combined with recombinant human BMP-2 (rhBMP-2), a potentially useful activation factor for bone repair. In this way, we try to combine the biological and filmogenic properties of this biopolymer with the osseoinductive ability of the rhBMP-2. Results showed that the chitosan films employed, without and with rhBMP-2 activation, are able to support cellular growth and proliferation on them and that only the rhBMP-2 activated ones are able to differentiate from a myoblastic mouse cell line (C2C12) toward osteoblastic phenotype. Osseoinduction properties of rhBMP-2 activated films persist for a long storage time. The in vivo experiments performed confirm the expectative created by the in vitro results obtained and are an indication that rhBMP-2 activated chitosan films could be a very attractive biomaterial for the enhancement of osseointegration of surgical prostheses and implants and for the purpose of tissue engineering bone regeneration.