Biomechanical Performance of Flexible Intramedullary Nails With End Caps Tested in Distal Segmental Defects of Pediatric Femur Models

Background: Unstable distal femoral fractures in children are challenging lesions with restricted surgical options for adequate stabilization. Elastic nails have become popular for treating femoral shaft fractures, yet they are still challenging for using in distal fractures. The aim of this study was to test whether end caps (CAP) inserted into the nail extremity improved the mechanical stabilization of a segmental defect at the distal femoral metaphyseal-diaphyseal junction created in an artificial pediatric bone model. Methods: Two 3.5-mm titanium elastic nails (TEN) were introduced intramedullary into pediatric femur models, and a 7.0-mm-thick segmental defect was created at the distal diaphyseal-metaphyseal junction. Nondestructive 4-point bending, axial-bending, and torsion tests were conducted. After this, the end caps were inserted into the external tips of the nails and then screwed into the bone cortex. The mechanical tests were repeated. Stiffness, displacement, and torque were analyzed using the Wilcoxon nonparametric test for paired samples. Results: In the combined axial-bending tests, the TEN + CAP combination was 8.75% stiffer than nails alone (P < 0.01); in torsion tests, the TEN + CAP was 14% stiffer than nails alone (P < 0.01). In contrast, the 4-point bending test did not show differences between the methods (P = 0.91, stiffness; P = 0.51, displacement). Thus, the end caps contributed to an increase in the construct stability for torsion and axial-bending forces but not for 4-point bending forces. Conclusions: These findings indicate that end caps fitted to elastic nails may contribute to the stabilization of fractures that our model mimics (small distal fragment, bone comminution, and distal bone fragment loss).

Transforming growth factor alpha immunoreactivity. A study in hepatocellular carcinoma and in non-neoplastic liver tissue

Background. Transforming growth factor alpha (TGF alpha) is an important mitogen that binds to epidermal growth factor receptor and is associated with the development of several tumors. Aims. Assessment of the immunoexpression of TGF alpha in hepatocellular carcinoma (HCC) and in non-neoplastic liver tissue and its relationship to morphological patterns of HCC. Material and methods. The immunohistochemical expression of TGF alpha was studied in 47 cases of HCC (27 multinodular, 20 nodular lesions). Five lesions measured up to 5 cm and 15 lesions above 5 cm. Thirty-two cases were graded as I or II and 15 as III or IV. The non-neoplastic tissue was examined in 40 cases, of which 22 had cirrhosis. HBsAg and anti-HCV were positive in 5/38 and 15/37 patients, respectively. The statistical analysis for possible association of immunostaining of TGF alpha and pathological features was performed through chi-square test. Results. TGF alpha was detected in 31.9% of the HCC and in 42.5% of the non-neoplastic. There was a statistically significant association between the expression of TGF alpha and cirrhosis (OR = 8.75, 95% CI = [1.93, 39.75]). The TGF alpha was detected more frequently in patients anti-HCV(+) than in those HBsAg(+). The immunoexpression of TGF alpha was not found related to tumor size or differentiation. In conclusion the TGF alpha is present in hepatocarcinogenesis in HBV negative patients. Further analysis is needed to examine the involvement of TGF alpha in the carcinogenesis associated with HCV and other possible agents. In addition, TGF alpha has an higher expression in hepatocyte regeneration and proliferation in cirrhotic livers than in HCC.

Functional properties of gelatin-based films containing Yucca schidigera extract produced via casting, extrusion and blown extrusion processes: A preliminary study

Gelatin-based films containing both Yucca schidigera extract and low concentrations of glycerol (0.25-8.75 g per 100 g protein) were produced by extrusion (EF) and characterized in relation to their mechanical properties and moisture content. The formulations that resulted in either larger or smaller elongation values were used to produce films via both blown extrusion (EBF) and casting (CF) and were characterized with respect to their mechanical properties, water vapor permeability, moisture content, solubility, morphology and infrared spectroscopy. The elongation of the EF films was significantly higher than that of the CF and EBF films. The transversal section possessed a compact, homogeneous structure for all of the films studied. The solubility of the films (36-40%) did not differ significantly between the different processes evaluated. The EBF films demonstrated lower water vapor permeability (0.12 g mm m-(2) h(-1) kPa(-1)) than the CF and EF films. The infrared spectra did not indicate any strong interactions between the added compounds. Thermoplastic processing of the gelatin films can significantly increase their elongation; however, a more detailed assessment and optimization of the extrusion conditions is necessary, along with the addition of partially hydrophobic compounds, such as surfactants. (C) 2012 Elsevier Ltd. All rights reserved.

Transmission of Human Herpesvirus Type 8 Infection Within Families in American Indigenous Populations From the Brazilian Amazon

Background. The intrafamilial dynamics of endemic infection with human herpesvirus type 8 (HHV-8) in Amerindian populations is unknown. Methods. Serum samples were obtained from 517 Amerindians and tested for HHV-8 anti-latent nuclear antigen (anti-LANA) and antilytic antibodies by immunofluorescence assays. Logistic regression and mixed logistic models were used to estimate the odds of being HHV-8 seropositive among intrafamilial pairs. Results. HHV-8 seroprevalence by either assay was 75.4% (95% confidence interval [CI]: 71.5%-79.1%), and it was age-dependent (P-trend<.001). Familial dependence in HHV-8 seroprevalence by either assay was found between mother-offspring (odds ratio [OR], 5.44; 95% CI: 1.62-18.28) and siblings aged >= 10 years (OR 4.42, 95% CI: 1.70-11.45) or siblings in close age range (<5 years difference) (OR 3.37, 95% CI: 1.21-9.40), or in families with large (>4) number of siblings (OR, 3.20, 95% CI: 1.33-7.67). In separate analyses by serological assay, there was strong dependence in mother-offspring (OR 8.94, 95% CI: 2.94-27.23) and sibling pairs aged >= 10 years (OR, 11.91, 95% CI: 2.23-63.64) measured by LANA but not lytic antibodies. Conclusions. This pattern of familial dependence suggests that, in this endemic population, HHV-8 transmission mainly occurs from mother to offspring and between close siblings during early childhood, probably via saliva. The mother to offspring dependence was derived chiefly from anti-LANA antibodies.

Caspase-mediated cleavage of the exosome subunit PM/Scl-75 during apoptosis

Recent studies have implicated the dying cell as a potential reservoir of modified autoantigens that might initiate and drive systemic autoimmunity in susceptible hosts. A number of subunits of the exosome, a complex of 3'→5' exoribonucleases that functions in a variety of cellular processes, are recognized by the so-called anti-PM/Scl autoantibodies, found predominantly in patients suffering from an overlap syndrome of myositis and scleroderma. Here we show that one of these subunits, PM/Scl-75, is cleaved during apoptosis. PM/Scl-75 cleavage is inhibited by several different caspase inhibitors. The analysis of PM/Scl-75 cleavage by recombinant caspase proteins shows that PM/Scl-75 is efficiently cleaved by caspase-1, to a smaller extent by caspase-8, and relatively inefficiently by caspase-3 and caspase-7. Cleavage of the PM/Scl-75 protein occurs in the C-terminal part of the protein at Asp369 (IILD369↓G), and at least a fraction of the resulting N-terminal fragments of PM/Scl-75 remains associated with the exosome. Finally, the implications of PM/Scl-75 cleavage for exosome function and the generation of anti-PM/Scl-75 autoantibodies are discussed.