Promoter methylation regulates Helicobacter pylori-stimulated cyclooxygenase-2 expression in gastric epithelial cells

Cyclooxygenase (COX)-2, the inducible form of the rate-limiting enzyme for prostaglandin synthesis, is up-regulated in gastrointestinal cancers and is a key mediator of epithelial cell growth. Helicobacter pylori is causally linked to gastric cancer. In H. pylori gastritis, COX-2 expression localizes to the subepithelial region, with variable levels in the epithelium. In contrast, in gastric cancer, COX-2 strongly predominates in the epithelium, suggesting that the transition to consistent epithelial COX-2 overexpression may be a critical molecular event in gastric carcinogenesis. Because aberrant promoter methylation inhibits expression of a variety of genes in gastrointestinal cancers, we sought to determine whether methylation of the COX-2 promoter could regulate the response to H. pylori in gastric epithelial cells. We assessed COX-2 expression and promoter methylation status in six gastric epithelial cell lines. In all four of the cell lines that exhibited basal expression of COX-2 and a significant increase in expression in response to H. pylori, the COX-2 promoter was unmethylated, whereas in the two cell lines that did not express COX-2, the COX-2 promoter was methylated. Treatment of COX-2-methylated cells with the demethylating agent 5-azacytidine had a modest effect on COX-2 expression, but when 5-azacytidine-treated cells were subsequently stimulated with H. pylori, there was a significant, 5-10-fold enhancement of both COX-2 mRNA and protein expression and release of the COX-2 product, prostaglandin E2. In contrast, in COX-2-expressing cell lines that were unmethylated at the COX-2 promoter, 5-azacytidine had no effect on H. pylori-stimulated COX-2 expression. These findings suggest that loss of COX-2 methylation may facilitate COX-2 expression and promote gastric carcinogenesis associated with H. pylori infection.     

Isolation of 45-hydroxyyessotoxin from mussels of the Adriatic Sea.

The diarrhetic shellfish toxin composition in the hepatopancreas of mussels from the northern Adriatic sea was investigated. The major toxins were shown to be yessotoxin (YTX), homoyessotoxin (homoYTX) and 45-hydroxyyessotoxin (45-OHYTX), identified by comparison of their chromatographic and spectral properties with those reported in the literature.     

Chondrosarcoma of the mandible: case report and literature review

Chondrosarcoma is a malignant cartilaginous tumor that rarely occurs in the maxillofacial bones. A 44-year-old woman complained about swelling and mild pain during mastication in the right parasymphysis region. Clinical and radiographic examinations revealed characteristics of osteosarcoma. A microscopic examination revealed an abundant proliferation of malignant neoplastic cartilage cells of varying sizes arranged as immature tissue and the absence of an osteoid matrix. This article presents a case of chondrosarcoma of the jaw and discusses the differences between osteosarcoma and chondrosarcoma.     

Prognosis of Regenerative Endodontic Procedures in Mature Teeth: A Systematic Review and Meta-Analysis of Clinical and Radiographic Parameters

This work aimed to investigate the use of Regenerative Endodontic Procedures (REP) on the treatment of pulp necrosis in mature teeth through systematic review and meta-analysis of evidence on clinical and radiographic parameters before and after REP. A search was performed in different databases on 9 September 2020, including seven clinical studies and randomized controlled trials (RCT). The methodological quality was assessed using Revised Cochrane risk-of-bias (RoB 2) and Before-and-After tools. Meta-analyses were performed to evaluate the success incidences regarding the reduction of periapical lesion and recovery of sensitivity. The certainty of the evidence was assessed using GRADE. Meta-analysis showed a high overall success of 0.95 (0.92, 0.98) I² = 6%, with high periapical lesion reduction at 12 months (0.93 (0.86, 0.96) I² = 37%) and by the end of follow-up (0.91 (0.83, 0.96) I² = 13%). Lower incidences of positive sensitivity response were identified for the electrical (0.58 (0.46, 0.70) I² = 51%) and cold tests (0.70 (0.54, 0.84) I² = 68%). The calculated levels of REP success were similar to those reported for immature teeth. With a very low certainty of evidence, the meta-analysis showed a high incidence of REP’s success for mature teeth with necrotic pulp evidenced by periapical lesion reduction and moderate positive responses to sensitivity tests.     

Acute post-traumatic optic nerve avulsion: case report

Optic nerve avulsion is a rare, but devastating complication. In this condition, the optic nerve is forcibly disinserted from the retina, choroid, and vitreous, and the lamina cribrosa is retracted from the scleral rim. If the media are clear, the avulsion is easily diagnosed. The appearance of the fundus is striking, with a hole or cavity where the optic disc has retracted into its dural sheath. The complementary examinations are not very accurate for the diagnosis of this pathology and with some residual vision, opaque media, that occur in partial avulsion, the diagnosis may be mistaken or delayed. In this article we report a case of complete optic nerve avulsion examined at the Retina and Vitreous Department of the "Hospital das Clínicas" of the Federal University of Uberlandia - MG - Brazil.     

From transit hub to major supplier of illicit cigarettes to Argentina and Brazil: the changing role of domestic production and transnational tobacco companies in Paraguay between 1960 and 2003

Background

Paraguay has reportedly been a major transit hub for illicit tobacco products since the 1960s, initially to supply markets in Argentina and Brazil and, more recently, other regional markets and beyond. However, to date there has been no systematic analysis, notably independent of the tobacco industry, of this trade including the roles of domestic production and transnational tobacco companies (TTCs). This article fills that gap by detailing the history of Paraguay’s illicit cigarette trade to Brazil and Argentina of TTC products and Paraguayan production between 1960 and 2003. The effective control of illicit cigarette flows, under Article 15 of the World Health Organization (WHO) Framework Convention on Tobacco Control (FCTC) and the Protocol to Eliminate the Illicit Trade in Tobacco Products, requires fuller understanding of the changing nature of the illicit trade.

Methods

We systematically searched internal industry documents to understand the activities and strategies of leading TTCs in Paraguay and subregion over time. We also mapped illicit trade volume and patterns using US government and UN data on the cigarette trade involving Paraguay. We then estimated Paraguay’s cigarette production from 1989 to 2003 using tobacco leaf flows from the United Nations Commodity Trade Statistics Database (UN Comtrade).

Results

We identify four phases in the illicit tobacco trade involving Paraguay: 1) Paraguay as a transit hub to smuggle BAT and PMI cigarettes from the U.S. into Argentina and Brazil (from the 1960s to the mid-1970s); 2) BAT and PMI competing in north-east Argentina (1989–1994); 3) BAT and PMI competing in southern and southern-east Brazil (mid to late 1990s); and 4) the growth in the illicit trade of Paraguayan manufactured cigarettes (from the mid- 1990s onwards). These phases suggest the illicit trade was seeded by TTCs, and that the system of supply and demand on lower priced brands they developed in the 1990s created a business opportunity for manufacturing in Paraguay. Brazil’s efforts to fight this trade, with a 150% tax on exports to Latin American countries in 1999, further prompted supply of the illicit trade to shift from TTCs to Paraguayan manufacturers.

Conclusion

This paper extends evidence of the longstanding complicity of TTCs in the illicit trade to this region and the consequent growth of Paraguayan production in the 1990s. Our findings confirm the need to better understand the factors influencing how the illicit tobacco trade has changed over time, in specific regional contexts, and amid tobacco industry globalization. In Paraguay, the changing roles of TTC and domestic production have been central to shifting patterns of illicit supply and distribution since the 1960s. Important questions are raised, in turn, about TTCs efforts to participate as legitimate partners in global efforts to combat the problem, including a leading role in data gathering and analysis.