Quantification of mechanoreceptors in the canine anterior cruciate ligament.

Ten canine anterior cruciate ligaments (ACLs) were harvested while preserving their bony attachments. Specimens were stained using a modified gold chloride technique, divided into thirds, and serially sliced at 0.5 microns. The slides were viewed to count the mechanoreceptors present. The average numbers of receptors found were: proximal 67, middle 43, and distal 18 (ANOVA: P < 0.001). The statistical test (Sheffé) revealed that the proximal third contained a greater mean number of receptors (S = 3.8). No significant difference was found between the number of receptors in the middle and distal thirds (S = 0.85).

[Experimental scoliosis in the minipig: study of vertebral deformations]. / La scoliose expérimentale chez le mini-porc: étude des déformations vertébrales.

UNLABELLED: The purpose of this study was to attempt an induction of a scoliotic deformation in the minipig by means of unilateral epiphysiodesis of the neurocetral cartilage (NCC) of 5 consecutive vertebrae, in order to understand the vertebral deformities genesis in the scoliotic pathology. The vertebral deformities induced in this quadruped have been compared to those of the pseudo-biped (chicken: induction of the scoliosis by means of pinealectomy) and to the known vertebral deformities in the human idiopathic scoliosis. MATERIAL AND METHODS: Eight Yucatan minipigs (1 month old) have been used. In the tested group (4 minipigs) underwent an epiphysiodesis (compression with a screw) on the NCC from T5 to T9. The control group (2 minipigs) underwent a perforation of the NCC without a screw placement from T5 to T9. The sham group (2 minipigs) underwent only a sus-periosted vertebral muscles clearing on the right side at the thoracic level. An X-ray follow-up at 1, 6 and 12 months has been performed. The minipigs have been sacrificed between 12 an 13 months post-operatively. The vertebrae were dissected for the macroscopic anatomic analysis. RESULTS: The X-ray follow-up shows an unfinished resorption of the curvature after one year post-operatively. The horizontal deformity of the vertebrae was more marked in those with the compressed (screw) NCC. The vertebral deformities in the minipig are similar to those found in the human and chicken. CONCLUSIONS: Although the curvatures are benign and often spontaneously resolvent, the comparison of the induced vertebral deformities to those obtained in a chicken (post-pinealectomie) and the human suggest that the NCC is likely involved in the vertebral deformities in the horizontal plan. Therefore the minipig does not seem to be a good experimental model for the scoliosis.

Hard, soft tissue and in vitro cell response to porous nickel-titanium: a biocompatibility evaluation.

Porous nickel-titanium (NiTi) alloys have demonstrated bone attachment as well as tissue ingrowth in the past. However, very few studies have compared porous NiTi soft and hard tissue reactions, and in vitro cell response. We therefore have evaluated the general muscle and bone reaction to porous nickel-titanium. The latter material was implanted in rabbit tibias and back muscle, and assessed after three, six and twelve weeks of implantation. Porous NiTi specimens did not cause any adverse effect regardless of both implantation site and post-surgery recovery time. Muscle tissue exhibited thin tightly adherent fibrous capsules with fibers penetrating into implant pores. We observed that attachment strength of the soft tissue to the porous implant seemed to increase with post-implantation time. Bone tissue demonstrated good healing of the osteotomy. There was bone remodeling characterized by osteoclastic and osteoblastic activity in the cortex. This general good in vivo biocompatibility with muscle and bone tissue corresponded very well with the in vitro cell culture results we obtained. Fibroblasts seeded on porous nickel-titanium sheets managed to grow into the pores and all around specimen edges showing an another interesting cytocompatibility behavior. These results indicate good biocompatibility acceptance of porous nickel-titanium and are very promising towards eventual NiTi medical device approbation.

[Bio-absorbable synthetic polyesters and tissue regeneration. A study of three-dimensional proliferation of ovine chondrocytes and osteoblasts]. / Polyesters biosynthétiques absorbables et régénération tissulaire. Etude de la prolifération tridimensionnelle de chondrocytes et ostéoblastes ovins.

The tissue engineering area henceforth calls more and more for bioabsorbable substrata made of biopolymers (collagen, laminin...) or polymers (PLA, PLGA, PGA...) to realize the three-dimensional culture of tissue equivalents. The poly (beta-hydroxybutyrate-beta-hydroxyvalerate), a biopolymer considered as being biodegradable and biocompatible, has been recently introduced for orthopaedic biomaterials and regeneration purposes. In our study, a PHB/9% HV polymer was transformed into 3D foams, then applied to the culture 3D of ovine chondrocytes (fibrous rings & growth plates) and osteoblasts (periostum). Sponges made of bovine type I collagen were used as references. Orthopaedic cells were isolated, prepared and sown by simple injection to the geometrical center of the substrata, then incubated from 0 to 35 days by changing the culture medium all 4 days. Maximal densities were reached after 21 days: 18-24.10(6) cells/g for the chondrocytes, 8-10.10(6) cells/g for the osteoblasts. The cellular proliferation was more marked, with highest cell densities, for the collagen sponges. Laser confocal microscopy shows that the cellular diffusion take place throughout the entire volume of the porous artificial substrata. Future studies will allow to apply the porous bioabsorbable substrata to high-density cell cultures, to the tissue engineering and regeneration, for example for orthopaedic tissues: cartilage, fibrocartilage and bone.

Immunohistochemical study of nerves in lumbar spine ligaments.

An indirect horseradish peroxidase immunohistochemical technique was used to identify neurofilaments protein-immunoreactive fibers in lumbar spine ligaments, from patients who underwent spinal surgery for disc herniation. Histologically, neural elements were abundant in all ligaments examined. In the ligamentum flavum the neurofilaments protein-immunoreactive nerve fibers were located especially close to blood vessels and fat globules. Bundles of nerve fibers were seen in all ligaments specimens except those from the ligamentum flavum. Supraspinous ligament and lumbodorsal fascia show also individual axons and free nerve endings. Contrary to the gold chloride impregnation method, immunohistochemical staining revealed no recognizable sensory corpuscles in these ligaments. This can be explained by the lack of immunoreaction of both the capsule of sensory corpuscles and the perineural sheaths of nerve fibers.

[Morphological study of the innervation of spinal ligaments in scoliotic patients]. / Etude morphologique de l'innervation des ligaments rachidiens de patients scoliotiques.

The purpose of this study was to investigate the morphology of nerve endings in spinal ligaments of scoliotic and normal patients. Nervous elements were investigated by means of gold chloride (AuCl2) impregnation and an indirect avidine-biotine peroxydase immunohistochemical method. Antiserum to a neurofilament protein (NFP) and S-100 protein were used as specific markers of nervous elements. In scoliotic and normal patients, immunohistochemical staining demonstrated a rich innervation of inter- and supra-spinous ligaments as compared to the yellow ligament. The immunohistochemical staining is however the most convenient and specific mean for studying the innervation in the ligaments. These two staining methods did not show any morphological difference in nervous elements of scoliotics ligaments as compared to the normal ligaments. These findings confront the role of the posterior ligamentous system in proprioception essential both in static and dynamic function of the sepine. However, the degeneration of neural elements in spinal ligaments could be involved in the etiology of the idiopathic scoliosis.

Sensory innervation of human thoracolumbar fascia. An immunohistochemical study.

We have studied the human thoracolumbar fascia by using antiserum against neurofilament protein (NFP) and S-100 protein to identify sensory nerve fibers and their endings. Seven surgical specimens from 7 patients were studied with light microscopy. In addition to free nerve endings, two types of encapsulated mechanoreceptors (Ruffini's and Vater-Pacini corpuscles) were identified. These findings support the hypothesis that the thoracolumbar fascia may play a neurosensory role in the lumbar spine mechanism.