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Biostite is a hydroxyapatite-derived biomaterial that is used in periodontal and bone reconstructive procedures due to its osteoconductive properties. Since the molecular effects of this biomaterial on osteoblasts are still unknown, we decided to assess whether it may specifically modulate osteoblast functions in vitro. We found that a brief exposure to Biostite significantly reduced the proliferation of MG-63 and SaOS-2 osteoblast-like cells to approximately 50% of the plateau value. Furthermore, gene array analysis of MG-63 cells showed that Biostite caused a differential expression of 37 genes which are involved in cell proliferation and interaction, and related to osteoblast differentiation and tissue regeneration. Results were confirmed by RT-PCR, Western blot, and by an increase in alkaline phosphatase (ALP) specific activity. Biostite also increased levels of polycystin-2, a mechano-sensitive Ca(2+) channel, a promising new marker of bone cell differentiation. Biostite, therefore, may directly affect osteoblasts by enhancing chondro/osteogenic gene expression and cytoskeleton-related signaling pathways, which may contribute to its clinical efficacy.

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34.8% of Italian schoolchildren carry more than 30% of their bodyweight at least once a week, exceeding limits proposed for adults. Given increasing evidence of back pain in children, the time has come to propose some limitations to backpack load.

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Interunit variability among bone densitometers is due to different factors, including different calibration procedures and algorithms and variability in photon source energies and/or intensities. Other factors, such as the choice of scan parameters or the analysis procedures, can also introduce variability. The new generation of dual-energy x-ray absorptiometry (DXA) has partially improved this situation. The aim of this study was to investigate the operator-dependent analysis procedures that can affect scan results and to evaluate the phantom and in vivo interunit variation of some DXA instruments. Four DXA instruments (QDR 1000 and 1000/W, Hologic, Inc.) were used. Potential sources of variability in the analysis procedures of anteroposterior lumbar spine and hip scans were considered: in most cases these procedures significantly influenced scan results. On lumbar spine, an enlargement of the scan window of less than 3 cm was responsible for an average increase in bone mineral density (BMD) of about 3%. On the hip, lowering the scan window by about 1 cm accounted for an increase in the whole-segment BMD of about 4%. After standardization of analysis procedures, interunit and intraunit coefficients of variation and percentage differences among instruments were less than 1% for all the parameters considered (area and bone mineral content and density) with both an anatomic and a geometric phantom, and in nine subjects scanned by two different devices the percentage difference in BMD was greater than 2%. This study shows that present interunit variability allows comparisons among laboratories, but only if highly standardized analysis procedures are used.

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The authors review the results of 100 cases of idiopathic scoliosis treated surgically by the Harrington procedure. The mean remove was 31 months. After a brief introductory section dealing with preparation methods, the paper illustrates the technicalities of the procedure, the usefulness of correction in two stages with a fortnight interval, the various types of mounting and postoperative care. They assess the improvement obtained in terms of vertebral rotation (mean correction achieved: 4.6 degrees, representing 10%) and of lateral flexion (49% improvement over pretreatment values), and they discuss in particular the need for a correct choice of instrument placement and appropriate evaluation of arthrodesis extent in view of avoiding loss of correction. While they acknowledge the value of the Harrington procedure in regard to correction of lateral flexion, the authors propose further refinement of the original method to include correction of vertebral rotation and so improve on current results.

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This paper describes the various technics of orthopedic surgery currently used to correct scoliosis and maintain correction. Among corrective methods they illustrate the use of the Cotrel plaster corset (E.D.F.) preceded by passive bipolar traction and autoelongation. Once correction is achieved, it must be maintained to the end skeletal growth; this is done with various types of orthopedic corsets (Lyonnais, La Padula, Milwaukee), which are used according to the patient's age and anatomical type of deformity. The authors discuss in particular the forces that are applied to the occiput and mandible with the Milwaukee corset (Logan, Cochran and Waugh), the values being recorded in diverse situations including the upright stance, ambulation, sitting position, position, supine position, and sleep (Galante, 1970). The authors also made a comparative study of the conventional Milwaukee corset (with broad chin bearing) versus the Milwaukee with hyoid bearing; and finally they illustrate the results obtained by Andriacchi and his associates in selecting the Milwaukee corset for patients with idiopathic scoliosis on the basis of the mathematical model of the rachis.

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