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p-Phenylenediamine antioxidants (PPDs) are rubber antioxidants that can suppress oxidation, heat, or light radiation to delay the aging of polymer components and extend the service life of rubber products. In recent years, PPDs have been found in the environment, and their ecological risks remain largely unknown, which cause widespread concern. In this work, a method of gas chromatography-tandem mass spectrometry (GC-MS/MS) with ultrasonic extraction was developed for the determination of PPDs in zebrafish embryos. In order to have good performance, extraction solvents and sorbents were optimized. Under optimal conditions, embryonic samples were combined with 5 mL of dichloromethane and ultrasonically extracted for 15 min. The extraction procedure was repeated twice, after that the resulting extracts were purified by 0.1 g primary secondary amine (PSA). Based on internal standard method, the analytes were detected using GC-MS/MS in selective reaction monitoring (SRM) mode with optimal parameters. The results showed that the chromatographic peaks of analyte were completely separated, and the baseline was smooth. The correlation coefficient (R2) of each analyte exceeded 0.99 in the concentration range of 0.1-200 μg/L. Method detection limits (MDLs) and method quantification limits (MQLs) were in the range of 0.38-0.68 ng/g and 1.28-2.28 ng/g, respectively. Except for the average recovery of N,N′-bis(methylphenyl)-1,4-benzenediamine (DTPD), which was higher than 120%, the average recoveries of N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD), N-phenyl-N′-cyclohexyl-p-phenylenediamine (CPPD) and N-isopropyl-N′-phenyl-1,4-phenylenediamine (IPPD) were 73.1%-109%, and the intra-day and inter-day relative standard deviations (RSDs) were 2.97%-15.0% and 4.76%-18.8%, respectively. In order to demonstrate the feasibility of this method, it was applied to detect PPDs in zebrafish embryos exposed to PPDs. The results indicated that PPD concentrations were 12.5-16.4 ng/g. After calculation, the measured bioconcentration factors of each analyte within 48 h were 1.70-33.6 L/kg. These values were much lower than the corresponding predicted bioconcentration factors, because PPD concentrations in vivo had not reached equilibrium during the exposure time of 48 h. This method is simple, sensitive, and suitable for the detection of PPDs in zebrafish embryos, which facilitates future bioaccumulation and toxicity mechanism studies for a comprehensive assessment of the ecological risks of PPDs.

Objective: To investigate the biomechanical effect of different intervertebral reconstructive heights on adjacent segments following C5/C6 anterior cervical discectomy and fusion (ACDF) through finite element analysis. Methods: A finite element model of intact C4–C7 segments was developed and validated for the present study. Five additional C4–C7 postoperative models were constructed with 100%, 125%, 150%, 175%, and 200% of the benchmark height of C5/C6 on the basis of the intact model. The changes in intradiscal pressure (IDP) and range of motion (ROM) of adjacent segments before and after reconstruction of C5/C6 were analyzed. Results: For the upper adjacent segment (C4/C5), the IDPs under the different loading conditions all increased after reconstruction. The maximum IDPs were 0.387, 0.489, 0.491, and 0.472 MPa under flexion, extension, axial rotation, and lateral bending, respectively, observed at the reconstructive height of 200%. The minimum IDPs were observed at 150% reconstructive height under all loading conditions except extension, and were 57, 86 and 81% of the maximum IDPs under flexion, axial rotation, and lateral bending, respectively. The minimum IDP under extension occurred when the reconstructive height is 125% of the benchmark height. For the lower adjacent segment (C6/C7), the IDPs of postoperative models under all loading conditions also increased compared to the preoperative model. The maximum IDPs after reconstruction under flexion, extension, axial rotation, and lateral bending were 0.402, 0.411, 0.461, and 0.497 MPa, respectively, when the height of the reconstruction was 200% of the benchmark. The minimum IDPs were observed after a reconstruction at 150% of the benchmark, and were 59%, 85%, 82%, and 81% of the maximum IDPs under flexion, extension, axial rotation, and lateral bending loading conditions. Conclusions: The reconstructive height is an important factor affecting the IDP and the ROM of adjacent segments after ACDF. To delay the adjacent segment disease, an intervertebral reconstructive height of 150% is an appropriate height in C5/C6 ACDF. [ABSTRACT FROM AUTHOR]

Background: Recent studies have demonstrated that synthetic dsRNAs may produce therapeutic effects in a target-independent manner through stimulation of the toll-like receptor-3 (TLR3)/interferon pathway; as a result, angiogenesis and proliferation of tumor cells are inhibited. Thus, this pathway may become a potential target of dsRNA in tumor suppression. In this study, we evaluated the role of synthetic dsRNA as a TLR3 synergist and by combining with sorafenib in anti-hepatocellular carcinoma (HCC) in vitro and in vivo.Methods: Four dsRNAs were designed and synthesized. One of them that was capable of activating TLR3 most effectively in human HCC cell line (HepG2.2.15) was selected as a TLR3 synergist (called BM-06). Subsequently, the expression of proteins relating to TLR3 signaling pathway, such as NF-κB, caspase 8 survivin, bcl-2 and PCNA affected by BM-06, sorafenib alone or in combination, was compared. The migration, proliferation and apoptosis of HepG2.2.15 cells were evaluated in presence of BM-06, sorafenib alone or in combination of both. The similar treatments were also applied in an SD rat primary HCC model.Results: qRT-PCR data showed that the expression of TLR3 and NF-κB in HepG2.2.15 cells was enhanced. BM-06 was selected as a TLR3 synergist capable of activating the TLR3/interferon pathway most effective among 4 synthetic dsRNAs. The migration and proliferation were significantly inhibited in treated HepG2.2.15 cells with BM-06 or Sorafenib alone as compared with PBS-sham control (P<0.01). However, the role of combination BM-06 with Sorafenib was the most prominent. Tumor cell apoptotic rate was increased by BM-06 or combination when compared to PBS or poly(I:C) (P<0.05). Similarly, in orthotopic HCC SD rats, the effect of the combination was superior to either agent alone on the inhibition of tumor growth and induction of HCC cell apoptosis (P<0.05).Conclusions: dsRNA alone was capable of inhibiting the proliferation of HepG2.2.15 cells and tumor growth of orthotopic HCC SD rats, but the effect of combination of dsRNA with sorafenib was more prominent. These findings implicate the potential role of combined use of a dsRNA, a TLR3 synergist, and sorafenib in inhibition of HCC. [ABSTRACT FROM AUTHOR]

Background: Primary hypertrophic osteoarthropathy (PHO) is a rare disease related to HPGD and SLCO2A1 gene mutation. Gastrointestinal involvement of PHO is even rarer with unknown pathogenesis. Clinical features of GI complication in PHO mimics other auto-immune based bowel entities, such as inflammatory bowel diseases and cryptogenic multifocal ulcerous stenosing enteritis (CMUSE). We aimed to analyze the clinical, genetic, radiological and pathological features of Chinese patients with PHO and determine the difference between PHO patients presenting with and without GI involvement.Methods: We reported two PHO cases with gastrointestinal involvement and reviewed all the studies of PHO in Chinese population published from January 1, 2000, to April 30, 2018. Clinical and genetic presentations of PHO in Chinese patients were analyzed. We compared the characteristics of those patients with gastrointestinal involvement against those without.Results: The two patients were both males with complete-form PHO for more than 10 years. GI related symptoms included diarrhea, chronic gastrointestinal hemorrhage, incomplete intestinal obstruction, anemia, and edema, which were unresponsive to etoricoxib treatment. Radiological examinations revealed segmental intestinal stenosis and thickened intestinal wall. Endoscopic findings included multiple ulcers and mucosal inflammation. Both patients had mutations of SLCO2A1 according to sequence analysis. The surgical pathology revealed chronic inflammation involving the intestinal mucosa and submucosa, similar to histological changes in CMUSE. According to the systemic review of 158 Chinese patients with PHO, 17.2% had gastrointestinal involvement, including peptic ulcer, gastric polyps, hypertrophic gastritis, and segmental intestinal stenosis. Patients with gastrointestinal involvement were more likely to have anemia (40.0% vs. 4.5%, P < 0.001), hypoalbuminemia (16.7% vs. 0.9%, P = 0.003), and myelofibrosis (19.0% vs. 0.9%, P = 0.002) than those without. Most patients with gastrointestinal complication had SLCO2A1 mutation (86.7%, 13 /15).Conclusions: Digestive tract involvement is uncommon in patients with PHO and often presents with anemia, and hypoalbuminemia resulted from intestinal inflammation. The intestinal pathologic characteristics are distinct from Crohn's disease but similar to CMUSE. Mutations in SLCO2A1 might be the pathogenic cause of GI involvement of PHO. NSAIDs may not be effective for PHO patients with gastrointestinal complications. [ABSTRACT FROM AUTHOR]