Prognostic significance of high-grade dysplasia in colorectal adenomas.

Aim  Colonoscopy to detect and remove polyps has contributed to a reduction in colorectal carcinoma. Three-year follow up is recommended for patients considered to be at high risk (at least three adenomas, adenoma ≥ 1 cm, villous or high-grade features). Our study focused on patients diagnosed with high-grade dysplasia with regard to initial management and follow up. Method  A search of patients who had had endoscopic removal of a high-grade adenoma was carried out. Patients with the following were excluded: follow up of \u3c 1 year, polyposis syndromes, prior colon cancer and a diagnosis of adenocarcinoma within 6 months following initial diagnosis. Results  Eighty-three patients treated between 1999 and 2007 for high-grade dysplasia (HGD) in a colorectal adenoma were identified. Over a median follow-up period of 4 years, 53 (64%) developed further adenomatous polyps. Among these, 7% had an adenoma with HGD or an adenocarcinoma. In all these patients, the initial high-grade adenoma was \u3e 1 cm in diameter. Initial follow-up colonoscopy was performed on average 7 months following the initial diagnosis. Ten per cent of patients underwent prophylactic segmental resection, and 6% received argon laser therapy. Conclusion  The study demonstrates that patients who have a colorectal adenoma \u3e 1 cm with HGD may be at high risk of developing further adenomas with HGD or carcinoma. Close follow up is warranted

Evolution of enhanced innate immune evasion by SARS-CoV-2

Emergence of SARS-CoV-2 variants of concern (VOCs) suggests viral adaptation to enhance human-to-human transmission1,2. Although much effort has focused on characterisation of spike changes in VOCs, mutations outside spike likely contribute to adaptation. Here we used unbiased abundance proteomics, phosphoproteomics, RNAseq and viral replication assays to show that isolates of the Alpha (B.1.1.7) variant3 more effectively suppress innate immune responses in airway epithelial cells, compared to first wave isolates. We found that Alpha has dramatically increased subgenomic RNA and protein levels of N, Orf9b and Orf6, all known innate immune antagonists. Expression of Orf9b alone suppressed the innate immune response through interaction with TOM70, a mitochondrial protein required for RNA sensing adaptor MAVS activation. Moreover, the activity of Orf9b and its association with TOM70 was regulated by phosphorylation. We propose that more effective innate immune suppression, through enhanced expression of specific viral antagonist proteins, increases the likelihood of successful Alpha transmission, and may increase in vivo replication and duration of infection4. The importance of mutations outside Spike in adaptation of SARS-CoV-2 to humans is underscored by the observation that similar mutations exist in the Delta and Omicron N/Orf9b regulatory regions

Mutant-IDH1-dependent chromatin state reprogramming, reversibility, and persistence

Mutations in IDH1 and IDH2 (encoding isocitrate dehydrogenase 1 and 2) drive the development of gliomas and other human malignancies. Mutant IDH1 induces epigenetic changes that promote tumorigenesis, but the scale and reversibility of these changes are unknown. Here, using human astrocyte and glioma tumorsphere systems, we generate a large-scale atlas of mutant-IDH1-induced epigenomic reprogramming. We characterize the reversibility of the alterations in DNA methylation, the histone landscape, and transcriptional reprogramming that occur following IDH1 mutation. We discover genome-wide coordinate changes in the localization and intensity of multiple histone marks and chromatin states. Mutant IDH1 establishes a CD24+ population with a proliferative advantage and stem-like transcriptional features. Strikingly, prolonged exposure to mutant IDH1 results in irreversible genomic and epigenetic alterations. Together, these observations provide unprecedented high-resolution molecular portraits of mutant-IDH1-dependent epigenomic reprogramming. These findings have substantial implications for understanding of mutant IDH function and for optimizing therapeutic approaches to targeting IDH-mutant tumors

A SARS-CoV-2 protein interaction map reveals targets for drug repurposing

The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 respiratory disease, has infected over 2.3 million people, killed over 160,000, and caused worldwide social and economic disruption1,2. There are currently no antiviral drugs with proven clinical efficacy, nor are there vaccines for its prevention, and these efforts are hampered by limited knowledge of the molecular details of SARS-CoV-2 infection. To address this, we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins physically associated with each using affinity-purification mass spectrometry (AP-MS), identifying 332 high-confidence SARS-CoV-2-human protein-protein interactions (PPIs). Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (29 FDA-approved drugs, 12 drugs in clinical trials, and 28 preclinical compounds). Screening a subset of these in multiple viral assays identified two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the Sigma1 and Sigma2 receptors. Further studies of these host factor targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19

Photocatalytic oxidation kinetics and mechanisms of meta-substituted phenols by TiO₂/UV : a molecular structure-reactivity study

The oxidation kinetics of m-substituted phenols by TiO2/UV were investigated. An attempt was made to correlate Swain-Lupton parameters (R) for aromatic substituents with the oxidation kinetic constants, based upon molecular structure and reactivity theory. Irradiation experiments were carried out with suspended aqueous TiO 2 powder and substrate mixture in a Rayonet Photochemical Reactor. Langmuir-Hinshelwood model was applied to obtain apparent kinetic rate constants. A linear correlation is observed between Langmuir-Hinshelwood kinetic parameters and Hammett constants for m-chloro, m-bromo and m-fluoro phenols. The changes in p values of Hammett plots at pH 3 suggest that the main degradation pathway may involve a positively charged intermediate, such as a radical cation formed by direct electron transfer to the positive holes at low pH. At high pH levels, however, substrate speciation, surface charge of the semiconductor, and bandgap shift appear to lead to a change in the degradation mechanism