Construction of uricase-overproducing strains of Hansenula polymorpha and its application as biological recognition element in microbial urate biosensor

<p>Abstract</p> <p>Background</p> <p>The detection and quantification of uric acid in human physiological fluids is of great importance in the diagnosis and therapy of patients suffering from a range of disorders associated with altered purine metabolism, most notably gout and hyperuricaemia. The fabrication of cheap and reliable urate-selective amperometric biosensors is a challenging task.</p> <p>Results</p> <p>A urate-selective microbial biosensor was developed using cells of the recombinant thermotolerant methylotrophic yeast <it>Hansenula polymorpha </it>as biorecognition element. The construction of uricase (UOX) producing yeast by over-expression of the uricase gene of <it>H. polymorpha </it>is described. Following a preliminary screening of the transformants with increased UOX activity in permeabilized yeast cells the optimal cultivation conditions for maximal UOX yield namely a 40-fold increase in UOX activity were determined.</p> <p>The UOX producing cells were coupled to horseradish peroxidase and immobilized on graphite electrodes by physical entrapment behind a dialysis membrane. A high urate selectivity with a detection limit of about 8 μM was found.</p> <p>Conclusion</p> <p>A strain of <it>H. polymorpha </it>overproducing UOX was constructed. A cheap urate selective microbial biosensor was developed.</p

Histone deacetylases in viral infections

Chromatin remodeling and gene expression are regulated by histone deacetylases (HDACs) that condense the chromatin structure by deacetylating histones. HDACs comprise a group of enzymes that are responsible for the regulation of both cellular and viral genes at the transcriptional level. In mammals, a total of 18 HDACs have been identified and grouped into four classes, i.e., class I (HDACs 1, 2, 3, 8), class II (HDACs 4, 5, 6, 7, 9, 10), class III (Sirt1–Sirt7), and class IV (HDAC11). We review here the role of HDACs on viral replication and how HDAC inhibitors could potentially be used as new therapeutic tools in several viral infections

AI is a viable alternative to high throughput screening: a 318-target study

: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery

Determinants of Second-Order Bile Duct Visualization at CT Cholangiography in Potential Living Liver Donors

View looking up the northwest corner; The Marriott Château Champlain is a hotel in Montreal, Quebec overlooking Dorchester Square. Once owned by CP Hotels and later sold off in the 1990s, it is now part of the Marriott hotel chain. Finished in time for the 1967 world's fair with its famous round porthole-like windows, Marriott Château Champlain stands 133 m (436 ft) high with 38 floors. It was built as the tallest hotel in Montreal and still holds that title to this date. Source: Wikipedia; http://en.wikipedia.org/wiki/Main_Page (accessed 2/8/2008

Determinants of Second-Order Bile Duct Visualization at CT Cholangiography in Potential Living Liver Donors

OBJECTIVE: The purpose of this article is to investigate the determinants of second-order bile duct visualization at CT cholangiography in living potential liver donors. MATERIALS AND METHODS: We retrospectively identified 143 potential living liver donors (83 men and 60 women; mean age, 37 years) evaluated with CT cholangiography, which included a slow infusion of iodipamide meglumine with CT acquisition 15 minutes after biliary contrast agent administration. Two readers independently scored the visualization of the second-order bile duct branches on a previously established 4-point scale (0 = not seen, 1 = faintly seen, 2 = well seen, and 3 = excellent visualization). Multivariate analysis was used to investigate the correlation between visualization scores and potential determinants of second-order bile duct opacification, specifically age, body mass index, creatinine level, total and direct bilirubin levels, alkaline phosphatase level, aspartate aminotransferase level, alanine aminotransferase level, patient maximum linear width, CT noise, and hepatosplenic attenuation difference at unenhanced CT. RESULTS: The mean (± SD) second-order bile duct visualization scores were 2.35 ± 0.66 and 2.55 ± 0.60 for readers 1 and 2, respectively. In the multivariate analysis, the only independent predictors of reduced second-order bile duct visualization were higher alkaline phosphatase level (p = 0.01) and higher CT noise (p = 0.02). CONCLUSION: Higher serum alkaline phosphatase level and higher CT noise in potential living liver donors indicate a higher risk of poor second-order bile duct visualization at CT cholangiography

Randomized Double-Blind Phase II Study of Regorafenib in Patients With Metastatic Osteosarcoma

PURPOSE: SARC024 is a phase II clinical trial of the multikinase inhibitor regorafenib in specific sarcoma subtypes, including advanced osteosarcoma. We hypothesized that regorafenib would improve progression-free survival (PFS) in patients with sarcoma and report the results of the osteosarcoma cohort. PATIENTS AND METHODS: This trial enrolled patients with progressive metastatic osteosarcoma with measurable disease by RECIST who had received at least one prior line of therapy. Patients were randomly assigned at a ratio of one to one to regorafenib or placebo. Crossover was allowed at time of disease progression. PFS was the primary end point of the study, which was powered to detect a difference of at least 3 months in median PFS. RESULTS: Forty-two patients from 12 centers were enrolled between September 2014 and May 2018. Median age was 37 years (range, 18 to 76 years). Patients had received an average of 2.3 prior therapy regimens. Ten patients receiving placebo crossed over to active drug at time of progression. Study enrollment was stopped early, after a data safety monitoring committee review. Median PFS was significantly improved with regorafenib versus placebo: 3.6 months (95% CI, 2.0 to 7.6 months) versus 1.7 months (95% CI, 1.2 to 1.8 months), respectively (hazard ratio, 0.42; 95% CI, 0.21 to 0.85; P = .017). In the context of the crossover design, there was no statistically significant difference in overall survival. Fourteen (64%) of 22 patients initially randomly assigned to regorafenib experienced grade 3 to 4 events attributed to treatment, including one grade 4 colonic perforation. CONCLUSION: The study met its primary end point, demonstrating activity of regorafenib in patients with progressive metastatic osteosarcoma. No new safety signals were observed. Regorafenib should be considered a treatment option for patients with relapsed metastatic osteosarcoma