No abstract

There are several gene therapy approaches to tissue regeneration. Although usually efficient, virusbased approaches may elicit an immune response against the viral proteins. An alternative approach, nonviral transfer, is safer, and can be controlled and reproduced. We hypothesized that in vivo bone formation could be achieved using human mesenchymal stem cells (hMSCs) nonvirally transfected with the human bone morphogenetic protein-2 (hBMP-2) or -9 (hBMP-9) gene. Human MSCs were transfected using nucleofection, a unique electropermeabilization-based technique. Postnucleofection, cell viability was 53.6 +/- 2.5% and gene delivery efficiency was 51% to 88% (mean 68.2 +/- 4.1%), as demonstrated by flow cytometry in enhanced green fluorescent protein (EGFP)-nucleofected hMSCs. Transgene expression lasted longer than 14 days and was very low 21 days postnucleofection. Both hBMP-2- and hBMP-9-nucleofected hMSCs in culture demonstrated a significant increase in calcium deposition compared with EGFP-nucleofected hMSCs. Human BMP-2- and hBMP-9-nucleofected hMSCs transplanted in ectopic sites in NOD/SCID mice induced bone formation 4 weeks postinjection. We conclude that in vivo bone formation can be achieved by using nonvirally nucleofected hMSCs. This could lead to a breakthrough in the field of regenerative medicine, in which safer, nonviral therapeutic strategies present a very attractive alternative.

Between 1978 and 1984, we examined and performed arthroscopy on 1000 consecutive patients. Ninety-eight of the 1000 had isolated ACL damage. These cases do not include patients with initial ACL injuries combined with other intraarticular damage. Diagnosis was by physical and arthroscopic examination. Examination took place an average 13.6 months after injury. Of the 98 isolated ACL injuries, 56 were complete ruptures and 42 were partial ruptures. In most cases of partial rupture, the clinical diagnosis was wrong. "Meniscal damage" was the usual diagnosis in these cases; the true diagnosis was made only by arthroscopic examination. Thirty-four of the 98 patients with isolated ACL injuries (30 men and 4 women) developed further intraarticular damage. Of these 34, 20 had complete ACL rupture and 14 had partial ACL rupture. Treatment after primary injury included physiotherapy in all patients and bracing in those whose knee was unstable during daily activities. Reconstructive surgical procedures were not performed in those patients. The time lapse from the primary to the secondary injury varied from 1 month to 20 years, with an average of 28 months. The secondary damage was caused by a secondary injury that was mild (22 cases) or developed insidiously (12 cases). Five types of secondary damage were observed: partial ACL tears that became complete--11 cases; meniscal tear--8 cases; loosening and subluxation of the anterior horn of the medial meniscus--14 cases; and fracture or damage to the articular condylar cartilage, with or without bone involvement--11 cases. It should be emphasized that the secondary damages were at times combined.

Fractures of the entire posterior process of the talus are rare and may be easily missed. Both the ankle joint and the subtalar joint are involved. This leads to malunion and early degenerative changes. We describe four patients with fractures of the posterior process of the talus which were initially missed. The patients were treated conservatively, and early mobilization or cast immobilization did not change the poor late results. The pitfalls in the diagnosis and imaging evaluation of such fractures are discussed.

Our prospective study evaluates the use of a knee brace with a silicon patellar support ring as a method of preventing anterior knee pain from developing in young persons undergoing strenuous physical exercise. We studied 60 young athletes, who qualified for a strenu ous physical training course and who had not suffered from anterior knee pain previously. Twenty-seven sub jects were in the brace group and 33 were in the nonbrace control group. The incidence of anterior knee pain syndrome increased with the intensity of exertion as the study progressed; i.e., subjects ran 6 km in the 1 st week, gradually increasing each week up to 42 km/week at the 8th week. Yet, there was a significant reduction in the incidence of the syndrome at the end of the study in male athletes who had applied the braces before exercise sessions and in the brace group as a whole, compared with the control group. Prophylactic use of the brace, as described, did not reduce the ability of the athletes who wore braces to improve their physical fitness parameters in response to exercise. These data indicate that the use of a brace may be an effective way to prevent the development of anterior knee pain syndromes in persons participating in strenuous and intensive physical exercise.