MicroRNAs (miRNAs) are small noncoding regulatory RNAs that reduce stability and/or translation of fully or partially sequence-complementary target mRNAs. Recent evidence indicates that miRNAs can function both as tumor suppressors and as oncogenes. It has been demonstrated that in glioblastoma multiforme miR-21 and 221 are upregulated whereas miR-128 and 181 are downregulated. Expression of miR-21, 221, 128a, 128b, 128c, 181a, 181b, 181c was studied using real-time quantitative reverse transcriptase polymerase chain reaction and northern blotting for human astrocytic tumors with different grade of malignancy. miR-21 and 221 were overexpressed in glioma samples, whereas miRNA 181b was downregulated compared with normal brain tissue. miRNA-21 was hyperexpressed in all tumor samples whereas higher levels of miRNA-221 were found in high-grade gliomas. This study is the first analysis of miRNAs in astrocytic tumor at different stages of malignancy. The different expression pattern observed in tumors at different stages of malignancy is probably dependent on the cell-specific repertoire of target genes of tumors sharing different molecular pathways activity and suggests miRNAs may have also a place in diagnosis and staging of brain tumors.
Study design: Definitive and unequivocal evidence to support the practice of early or late surgery is still lacking in clinical studies. Accordingly, meta-analysis is one of the few methods that offer a rational, statistical approach to management decision. A review of the clinical literature on spinal cord injury with emphasis on the role of early surgical decompression and a meta-analysis of results was performed. Objectives: To determine whether neurological outcome is improved in traumatic spinal cordinjured patients who had surgery within 24 h as compared with those who had late surgery or conservative treatment. Methods: A Medline search covering the period 1966-2000, supplemented with manual search, was used to locate studies containing information on indication, rationale and timing of surgical decompression after spinal cord injuries. The analysis included a total of 1687 eligible patients. Results: Statistically, early decompression resulted in better outcome compared with both conservative (Po0.001) and late management (Po0.001). Nevertheless, analysis of homogeneity showed that only data regarding patients with incomplete neurological deficits who had early surgery were reliable. Conclusions: Although statistically the percentage of patients with incomplete neurological deficits improving after early decompression appear 89.7% (95% confidence interval: 83.9, 95.5%), to be better than with the other modes of treatment when taking into consideration the material available for analysis and the various other factors including clinical limitations; early surgical decompression can only be considered as practice option for all groups of patients.
Object. Posterolateral fusion involving instrumentation-assisted segmental fixation represents a valid procedure in the treatment of lumbar instability. In cases of anterior column failure, such as in isthmic spondylolisthesis, supplemental posterior lumbar interbody fusion (PLIF) may improve the fusion rate and endurance of the construct. Posterior lumbar interbody fusion is, however, a more demanding procedure and increases costs and risks of the intervention. The advantages of this technique must, therefore, be weighed against those of a simple posterior lumbar fusion.Methods. Thirty-five consecutive patients underwent pedicle screw fixation for isthmic spondylolisthesis. In 18 patients posterior lumbar fusion was performed, and in 17 patients PLIF was added. Clinical, economic, functional, and radiographic data were assessed to determine differences in clinical and functional results and biomechanical properties.At 2-year follow-up examination, the correction of subluxation, disc height, and foraminal area were maintained in the group in which a PLIF procedure was performed, but not in the posterolateral fusion—only group (p < 0.05). Nevertheless, no statistical intergroup differences were demonstrated in terms of neurological improvement (p = 1), economic (p = 0.43), or functional (p = 0.95) outcome, nor in terms of fusion rate (p = 0.49).Conclusions. The authors' findings support the view that an interbody fusion confers superior mechanical strength to the spinal construct; when posterolateral fusion is the sole intervention, progressive loss of the extreme correction can be expected. Such mechanical insufficiency, however, did not influence clinical outcome.
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