Study on the effects of nitrilotriproprionic acid and 4,5-dihydroxy-1,3-benzene disulphonate on the fractionation of beryllium in human serum using graphite furnace atomic absorption spectrometry

<p>Abstract</p> <p>Background</p> <p>Occupational exposure to beryllium may cause Chronic Beryllium Disease (CBD), a lung disorder initiated by an electrostatic interaction with the MHC class II human leukocyte antigen (HLA). Molecular studies have found a significant correlation between the electrostatic potential at the HLA-DP surface and disease susceptibility. CBD can therefore be treated by chelation therapy. In this work, we studied the effect of two complexing agents, nitrilotriproprionic acid (NTP) and 4,5-dihydroxy-1,3-benzene disulphonate (Tiron), on the fractionation of beryllium in human serum analysed by graphite furnace atomic absorption spectrometry (GFAAS).</p> <p>Results</p> <p>We found the average serum beryllium concentration of fourteen non-exposed individuals to be 0.53 (± 0.14) μg l^-1, with 21 (± 3)% of the beryllium mass bound to the low molecular weight fraction (LMW), and 79 (± 3)% bound to the high molecular weight fraction (HMW). The addition of Tiron increased the beryllium mass in the HMW fraction, while NTP was not seen to have any influence on the fractionation of beryllium between the two fractions. NTP was, however, shown to complex 94.5% of the Be mass in the LMW fraction. The beryllium GFAAS detection limit, calculated as three times the standard deviation of 10 replicates of the lowest standard (0.05 μg L^-1), was 6.0 (± 0.2) ng L^-1.</p> <p>Conclusion</p> <p>The concentration of beryllium or its fractionation in human serum was not affected by sex or smoking habit. On average, three quarters of the beryllium in serum were found in the HMW fraction. Of the two ligands tested, only Tiron was effective in mobilising beryllium under physiological conditions, thus increasing the Be content in the HMW fraction.</p

Comparison between anterior cervical discectomy fusion and cervical corpectomy fusion using titanium cages for reconstruction: analysis of outcome and long-term follow-up

Retrospective comparative study of 80 consecutive patients treated with either anterior cervical discectomy fusion (ACDF) or anterior cervical corpectomy fusion (ACCF) for multi-level cervical spondylosis. To compare clinical outcome, fusion rates, and complications of anterior cervical reconstruction of multi-level ACDF and single-/multi-level ACCF performed using titanium mesh cages (TMCs) filled with autograft and anterior cervical plates (ACPs). Reconstruction of the cervical spine after discectomy or corpectomy with titanium cages filled with autograft has become an acceptable alternative to both allograft and autograft; however, there is no data comparing the outcome of multi-level ACDF and single-/multi-level ACCF using this reconstruction. We evaluated 80 consecutive patients who underwent surgery for the treatment of multi-level cervical spondylosis at our institution from 1998 to 2001. In this series, 42 patients underwent multi-level ACDF (Group 1) and 38 patients underwent ACCF (Group 2). Interbody TMCs and local autograft bone with ACPs were used in both procedures. Medical records were reviewed to assess outcome. Clinical outcome was measured by Odom’s criteria. Operative time and blood loss were noted. Radiographs were obtained at 6 and 12 weeks, 6 months, 1 year, and 2 years (if necessary). Early hardware failures and pseudarthroses were noted. Cervical sagittal curvature was measured by Ishihara’s index at 1 year. Group 1 had a mean age 46.2 years (range 35–60 years). Group 2 had a mean age 50.1 years (range 35–70 years).The operative time was significantly lower (P < 0.001) and blood loss significantly higher (P < 0.001) in Group 2 than in Group 1. At a minimum of 1 year follow up, patients in both groups had equivalent improvement in their clinical symptoms. The fusion rates for Group 1 were 97.6 and 92.1% for Group 2. The rates of early hardware failure were higher in Group 2 (2.6%) than in Group 1 (0%). The fusion rates for Group 1 were not significantly higher than Group 2 (P > 0.28). There was one patient in Group 1 and 2 patients in Group 2 with pseudarthroses. Complication rates in Group 2 were not significantly higher (P > 0.341). Cervical lordosis was well-maintained (80%) in both groups. Both multi-level ACDF and ACCF with anterior cervical reconstruction using TMC filled with autograft and ACP for treatment of multi-level cervical spondylosis have high fusion rates and good clinical outcome. However, there is a higher rate of early hardware failure and pseudarthroses after ACCF than ACDF. Hence, in the absence of specific pathology requiring removal of vertebral body, multi-level ACDF using interbody cages and autologous bone graft could result in lower morbidity

4- and 5-level anterior fusions of the cervical spine: review of literature and clinical results

In the future, there will be an increased number of cervical revision surgeries, including 4- and more-levels. But, there is a paucity of literature concerning the geometrical and clinical outcome in these challenging reconstructions. To contribute to current knowledge, we want to share our experience with 4- and 5-level anterior cervical fusions in 26 cases in sight of a critical review of literature. At index procedure, almost 50% of our patients had previous cervical surgeries performed. Besides failed prior surgeries, indications included degenerative multilevel instability and spondylotic myelopathy with cervical kyphosis. An average of 4.1 levels was instrumented and fused using constrained (26.9%) and non-constrained (73.1%) screw-plate systems. At all, four patients had 3-level corpectomies, and three had additional posterior stabilization and fusion. Mean age of patients at index procedure was 54 years with a mean follow-up intervall of 30.9 months. Preoperative lordosis C2-7 was 6.5° in average, which measured a mean of 15.6° at last follow-up. Postoperative lordosis at fusion block was 14.4° in average, and 13.6° at last follow-up. In 34.6% of patients some kind of postoperative change in construct geometry was observed, but without any catastrophic construct failure. There were two delayed unions, but finally union rate was 100% without any need for the Halo device. Eleven patients (42.3%) showed an excellent outcome, twelve good (46.2%), one fair (3.8%), and two poor (7.7%). The study demonstrated that anterior-only instrumentations following segmental decompressions or use of the hybrid technique with discontinuous corpectomies can avoid the need for posterior supplemental surgery in 4- and 5-level surgeries. However, also the review of literature shows that decreased construct rigidity following more than 2-level corpectomies can demand 360° instrumentation and fusion. Concerning construct rigidity and radiolographic course, constrained plates did better than non-constrained ones. The discussion of our results are accompanied by a detailed review of literature, shedding light on the biomechanical challenges in multilevel cervical procedures and suggests conclusions