Clinical outcome of veterans with acute coronary syndrome who had been exposed to agent orange

Identification and characterization of differentially expressed lncRNA in 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced cleft palate

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a ubiquitous environmental pollutant and also a strong teratogen for cleft palate (CP). But up to now, the underlying molecular mechanisms of TCDD-induced CP are largely unknown. More recently, accumulating evidences are revealing important roles of long noncoding RNAs (lncRNAs) in all kinds of diseases including CP. However, the role and molecular mechanism of lncRNAs in TCDD-induced CP are still largely unexplored. Thus, identification of differentially expressed lncRNA (DEL) might help figuring out the mechanism of CP induced by TCDD. In this study, a CP offspring model of C57BL/6 female mice was generated by TCDD (64 µg/kg body weight) induce on embryo day 10 (E10). The incidence rate of CP was 100% in the TCDD group (105) after cervical dislocation on E16. Then, the high-throughput RNA sequencing (RNA-seq) was established to search a comprehensive profile of the lncRNAs. In addition, a coexpression network of lncRNA and messenger RNA (mRNA) was performed to discern potential mechanism. The result showed that 26,246 novel lncRNAs and 9635 known lncRNAs were screened out, and 413 lncRNA transcripts and 65 mRNA transcripts were identified as being significantly different between the CP group and control group. Notably, we found that there are seven lncRNAs that can target Smad1 and Smad5, which are key molecules of bone morphogenetic protein (BMP) signaling pathway, which suggested that they may be concerned with BMP signaling in TCDD-induced CP. In addition, some lncRNAs targeted the important molecules of Hippo and Wnt signaling pathways. These results suggested that characteristic lncRNA alterations may play a critical role in TCDD-induced CP, which provided a theoretical basis for further research.

TCDD induces the hypoxia-inducible factor (HIF)-1α regulatory pathway in human trophoblastic JAR cells

The exposure to dioxin can compromise pregnancy outcomes and increase the risk of preterm births. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been demonstrated to induce placental hypoxia at the end of pregnancy in a rat model, and hypoxia has been suggested to be the cause of abnormal trophoblast differentiation and placental insufficiency syndromes. In this study, we demonstrate that the non-hypoxic stimulation of human trophoblastic cells by TCDD strongly increased hypoxia inducible factor-1 alpha (HIF-1α) stabilization. TCDD exposure induced the generation of reactive oxygen species (ROS) and nitric oxide. TCDD-induced HIF-1α stabilization and Akt phosphorylation was inhibited by pretreatment with wortmannin (a phosphatidylinositol 3-kinase (PI3K) inhibitor) or N-acetylcysteine (a ROS scavenger). The augmented HIF-1α stabilization by TCDD occurred via the ROS-dependent activation of the PI3K/Akt pathway. Additionally, a significant increase in invasion and metallomatrix protease-9 activity was found in TCDD-treated cells. The gene expression of vascular endothelial growth factor and placental growth factor was induced upon TCDD stimulation, whereas the protein levels of peroxisome proliferator-activated receptor γ (PPARγ), PPARγ coactivator-1α, mitochondrial transcription factor, and uncoupling protein 2 were decreased. Our results indicate that an activated HIF-1α pathway, elicited oxidative stress, and induced metabolic stress contribute to TCDD-induced trophoblastic toxicity. These findings may provide molecular insight into the TCDD-induced impairment of trophoblast function and placental development.

CASE REPORT Sternal Chondrosarcoma After Sternotomy for Coronary Artery Bypass Grafting

OBJECTIVE

Primary bony tumors of the chest wall are usually benign and most commonly located in the ribs or sternum. Chondrosarcoma is regarded as one of the most frequent primary malignancies of the chest wall and its incidence after a sternotomy for a cardiac procedure is extremely rare. We present a case of sternal chondrosarcoma.

METHODS

The patient presented with a sternal mass 4 years after undergoing coronary artery bypass grafting for ischemic coronary artery disease. The mass originally emanated from the upper portion of the patients' sternum and then rapidly enlarged to include the anterior aspects of his neck. Radiologic imaging studies were undertaken: computed tomographic scan and magnetic resonance imaging, with surgical intervention for excision.

RESULTS

Computed tomographic scan and magnetic resonance imaging established an 8.4 × 6.2 × 8.6 cm(3) complex solid tissue mass within the lower neck arising from the sternal manubrium, with extensive bone destruction. Computed tomography-guided biopsy showed cells of uncertain significance. Surgical excision was performed and the mass was diagnosed as a grade II chondrosarcoma.

DISCUSSION

Primary sarcomas of the sternum though uncommon are potentially curable with wide surgical excision. Success depends on tumor histologic type and grade, which dictate recurrence.