The X-ray structure of the nuclear factor-jB (NF-jB) p52:RelB:jB DNA complex reveals a new recognition feature not previously seen in other NF-jB:jB DNA complexes. Arg 125 of RelB is in contact with an additional DNA base pair. Surprisingly, the p52:RelB R125A mutant heterodimer shows defects both in DNA binding and in transcriptional activity only to a subclass of jB sites. We found that the Arg 125-sensitive jB sites contain more contiguous and centrally located A:T base pairs than do the insensitive sites. A protein-induced kink observed in this complex, which used an AT-rich jB site, might allow the DNA contact by Arg 125; such a kink might not be possible in complexes with non-AT-rich jB sites. Furthermore, we show that the p52:RelB heterodimer binds to a broader spectrum of jB sites when compared with the p50:RelA heterodimer. We suggest that the p52:RelB heterodimer is more adaptable to complement sequence and structural variations in jB sites when compared with other NF-jB dimers.

Given similar clinical outcomes, microfracture and OAT are both viable, cost-effective first-line treatment options for these injuries.

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Femoral trochleoplasties resurfaced with autogenous free periosteal grafts in six dogs were compared to femoral trochleoplasties performed without grafts in six dogs. The grafts produced cartilage as early as 4 weeks after surgery; however, it was fibrocartilage rather than normal hyaline articular cartilage. The trochleoplasties not resurfaced with periosteum also healed with fibrocartilage but not until 40 weeks postoperatively. The grafted stifles had less patellar cartilage damage when compared to trochleoplasties left to heal without resurfacing. EAR LIMB LAMENESS associated with patellar luxa-R tion in the dog is a common clinicalOne commonly employed method of surgically stabilizing the patella is to deepen the trochlear groove. The newly enlarged medial and lateral trochlear ridges restrain the patella. Trochlear rece~sion,~ cartilage flap ~ulcoplasty,~ and trochleopla~ty~,~ are methods of deepening the trochlear groove. Trochlear recession preserves the articular cartilage but is technically demanding in the toy breed dog. Cartilage flap sulcoplasty maintains the articular cartilage, but elevation without fracturing the cartilage becomes increasingly difficult after 5 months of age. Trochleoplasty is the most common technique used to deepen the trochlear groove. This procedure is simple and quick to perform but destroys the normal articular cartilage.Autogenous free periosteal grafts in rabbits filled articular cartilage defects with a hyaline-like cartilage similar to normal cartilage after 4The healed tissue remained cartilaginous for at least 1 year.The purpose of this investigation was to determine the chondrogenic potential of free autogenous periosteal grafts used in resurfacing articular cartilage defects produced by femoral trochleoplasties in the dog. Materials and MethodsTwelve 5-month-old conditioned mixed breed dogs of either sex were divided into two groups. Six dogs (group A) underwent a trochleoplasty alone, while six dogs (group B) underwent a trochleoplasty that was resurfaced with a free autogenous periosteal graft. Postoperatively, the leg was placed in a soft padded bandage for 4 days to prevent swelling and postoperative discomfort. Each dog was housed individually in cages measuring 90 x 87.5 x 60 cm, and had free exercise for 30 minutes daily. Clinical parameters were evaluated at 4 week intervals and at the time of death. Two dogs from each group were euthanized at 4, 10, and 40 weeks. Each stifle was examined grossly and microscopically. Surgical ProcedureThe operated leg was prepared for surgery using aseptic technique. The dog was anesthetized and placed in lateral recumbency, and the surgical site was draped for sterile surgery. A standard lateral arthrotomy* was performed to expose the femoral trochlear groove. A femoral trochleoplasty was prepared, the width of