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High mobility group B (HMGB) proteins are highly abundant non-histone chromatin proteins that play important roles in the execution and control of many nuclear functions. Based on homology searches, we identified the coding sequence for the TcHMGB protein, an HMGB family member from Trypanosoma cruzi. TcHMGB has two HMG box domains, similar to mammalian HMGBs, but lacks the typical C-terminal acidic tail. Instead, it contains a 110 amino acid long N-terminal domain. The TcHMGB N-terminal domain is conserved between the TriTryp sequences (70-80% similarity) and seems to be characteristic of kinetoplastid HMGBs. Despite these differences, TcHMGB maintains HMG box architectural functions: we demonstrated that the trypanosomatid HMGB binds distorted DNA structures such as cruciform DNA in gel shift assays. TcHMGB is also able to bend linear DNA as determined by T4 ligase circularization assays, similar to other HMGB family members. Immunofluorescence and western blot assays showed that TcHMGB is a nuclear protein expressed in all life cycle stages. Protein levels, however, seem to vary throughout the life cycle, which may be related to previously described changes in heterochromatin distribution and transcription rates., (Copyright © 2011 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.)

A total of 25 pathologic fractures in patients affected with thoracolumbar vertebral metastases associated with neurologic deficit are reported. None of the pathologic fractures were stable, while 14 were unstable and 11 were very unstable. Decompression with intralesional excision of the neoplastic mass compressing the dural sac was performed in all of the cases. Posterior stabilization was performed in the first cases using systems of sublaminar segmental fixation, and thereafter using systems of pedicle fixation. Removal of the vertebral body followed by anterior fusion after preventive posterior stabilization was performed in 2 cases. Pain symptoms regressed in 85% of the cases and in more than 50% of the patients there was improvement in the neurologic findings and in vertebral deformity consequent to fracture. Mean survival rate was 12 months. Despite the limited number of cases posterior stabilization of pathological fractures is a good choice of treatment in patients with severe neurologic deficit.

The authors analyzed 15 patients affected with achondroplastic dwarfism with vertebral deformity treated surgically between 1976 and 1994. The forms represented were: achondroplasia; diastrophic dwarfism; spondyloepiphyseal achondroplasia. The types of vertebral deformity were: kyphosis: 12 (angular: 6; regular: 6); scoliosis: 1; kyphoscoliosis: 2. Neurological symptoms were present in 10 patients. Treatment was as follows: laminectomy: 8; posterior fusion with instrumentation: 2; anterior fusion: 2; anterior fusion with laminectomy and posterior fusion: 3. There were postoperative neurological complications in 4 cases (27%). Fusion must be performed early in angular kyphosis in the adult in order to prevent neurological symptoms. Wide laminectomies do not require associated fusion because they do not cause late vertebral instability.