Quantification of Strand Accessibility in Biostable DNA Origami with Single-Staple Resolution

DNA-based nanostructures are actively gaining interest as tools for biomedical and therapeutic applications following the recent development of protective coating strategies prolonging structural integrity in physiological conditions. For tailored biological action, these nanostructures are often functionalized with targeting or imaging labels using DNA base pairing. Only if these labels are accessible on the structure's surface will they be able to interact with their intended biological target. However, the accessibility of functional sites for different geometries and environments, specifically after the application of a protective coating, is currently not known. Here, we assay this accessibility on the level of single handle strands with two- and three-dimensional resolution using DNA-PAINT and show that the hybridization kinetics of top and bottom sides on the same nanostructure linked to a surface remain unaltered. We furthermore demonstrate that the functionality of the structures remains available after an oligolysine-PEG coating is applied, enabling bioassays where functionality and stability are imperative

Safety of treatments for inflammatory bowel disease: Clinical practice guidelines of the Italian Group for the Study of Inflammatory Bowel Disease (IG-IBD)

Inflammatory bowel diseases are chronic conditions of unknown etiology, showing a growing incidence and prevalence in several countries, including Italy. Although the etiology of Crohn's disease and ulcerative colitis is unknown, due to the current knowledge regarding their pathogenesis, effective treatment strategies have been developed. Several guidelines are available regarding the efficacy and safety of available drug treatments for inflammatory bowel diseases. Nevertheless, national guidelines provide additional information adapted to local feasibility, costs and legal issues related to the use of the same drugs. These observations prompted the Italian Group for the Study of Inflammatory Bowel Disease (IG-IBD) to establish Italian guidelines on the safety of currently available treatments for Crohn's disease and ulcerative colitis. These guidelines discuss the use of aminosalicylates, systemic and low bioavailability corticosteroids, antibiotics (metronidazole, ciprofloxacin, rifaximin), thiopurines, methotrexate, cyclosporine A, TNFα antagonists, vedolizumab, and combination therapies. These guidelines are based on current knowledge derived from evidence-based medicine coupled with clinical experience of a national working group

Nucleic acids presenting polymer nanomaterials as vaccine adjuvants

Most vaccines developed today include only the antigens that best stimulate the immune system rather than the entire virus or microbe, which makes vaccine production and use safer and easier, though they lack potency to induce acceptable immunity and long-term protection. The incorporation of additional immune stimulating components, named adjuvants, is required to generate a strong protective immune response. Nucleic acids (DNA and RNA) and their synthetic analogs are promising candidates as vaccine adjuvants activating Toll-like receptors (TLRs). Additionally, in the last few years several nanocarriers have emerged as platforms for targeted co-delivery of antigens and adjuvants. In this review, we focus on the recent developments in polymer nanomaterials presenting nucleic acids as vaccine adjuvants. We aim to compare the effectiveness of the various classes of polymers in immune modulating materials (nanoparticles, dendrimers, single-chain particles, nanogels, polymersomes and DNA-based architectures). In particular, we address the critical role of parameters such as size, shape, complexation and release of TLR ligands, cellular uptake, stability, toxicity and potential importance of spatial control in ligand presentation

Prevention of post-operative recurrence of Crohn's disease requires adequate mucosal concentration of mesalazine. Gruppo Italiano per lo Studio del Colon e del Retto.

Background: Surgical resection of Crohn's disease is followed by early recurrence in a high percentage of patients, Mesalazine has been shown to be effective in the prevention of post-operative recurrence, but some 50% of patients under treatment recur at 3 years of follow-up, Aim: To establish whether the mucosal concentration of mesalazine might affect the development of post-operative recurrence. Methods: Colon-ileoscopy was performed in 25 consecutive patients resected for Crohn's disease. The mean time from surgery was 14 months. After the operation, all patients were taking oral mesalazine (Asacol, 2.4 g/day), Ten patients showed signs of endoscopic recurrence (apthae, ulcers, narrowing of the lumen) in the neoterminal ileum, five of whom also showed juxta-anastomotic colonic involvement. Fifteen patients were free of recurrence. At endoscopy, four biopsies were taken from the perianastomotic area (two specimens at the ileal site and two specimens at the colonic site of the anastomosis), The specimens were weighed and immediately frozen at -80 degrees C. Mesalazine concentration (ng/mg) was measured in tissue homogenates by highperformance liquid chromatography with elcctrochemical detection. Fisher's exact test was used for the statistical analysis, Results: The mean value of mucosal mesalazine concentration, expressed as ng/mg of tissue, was significantly lower in patients with recurrence than in those without recurrence both in the ileum (mean +/- s.d.: 21.6 +/- 28.3 vs. 70.9 +/- 47.4: P = 0.007) and in the colon (25.8 +/- 26.4 vs, 60.3 +/- 32.5: P = 0.010), Conclusions: The mucosal conentration of mesalazine in the juxta-anastomatic area is significantly lower in patients with recurrence than in those free of recurrence. These data could suggest an association between mucosal mesalazine concentrations and the clinical effectiveness of the drug

Anastomotic configuration and mucosal 5-aminosalicyclic acid (5-ASA) concentrations in patients with Crohn's disease: a GISC study. Gruppo Italiano per lo Studio del Colon e del Retto

OBJECTIVE: Recurrence of Crohn's disease quite inevitably occurs after resection of distal small bowel and proximal colon, involving the neoterminal ileum close to the anastomosis. Oral 5-aminosalicylic acid (5-ASA) administered soon after surgery delays recurrence and reduces its severity. We recently observed that in operated patients submitted to prophylactic treatment with oral 5-ASA the rate of recurrence was significantly higher in those with end-to-end anastomosis than in those with other types of anastomosis (end-to-side, side-to-side). The hypothesis investigated in the present study was that patients with end-to-side or side-to-side anastomosis would benefit from a higher mucosal concentration of 5-ASA with respect to patients with end-to-end anastomosis. Therefore, the mucosal 5-ASA concentration was measured in the perianastomotic area of both groups. METHODS: The study was carried out in 19 patients submitted to radical surgery for Crohn's ileitis or ileocolitis, under oral prophylactic treatment with 5-ASA (Asacol). All patients were on regular endoscopic follow-up and were free of recurrence. Two biopsies were collected 3 cm from the anastomosis, in the neoterminal ileum, and two biopsies were collected at the colonic site 3 cm below the anastomosis. 5-ASA concentrations (ng/mg) were measured in tissue homogenates by high-performance liquid chromatography (HPLC) with electrochemical detection. RESULTS: The mucosal concentration of 5-ASA in the neoterminal ileum was significantly lower in patients with end-to-end anastomosis than in those with other types of anastomosis (median values: 29.4 ng/mg vs 92.9 ng/mg respectively; p 90 ng/mg, compared with the 57% of patients in the group with other types of anastomosis. No differences were observed for colonic biopsies. CONCLUSIONS: The different mucosal concentrations in these two groups may be explained by the difference in segmental transit time induced by the different anastomotic configurations. A slower preanastomotic transit time, demonstrated in patients with end-to-side or side-to-side anastomosis, could offer a prolonged contact time between the intestinal content and the mucosa, resulting in an increase in drug absorption

Inter-observer agreement in endoscopic scoring systems: Preliminary report of an ongoing study from the Italian Group for Inflammatory Bowel Disease (IG-IBD).

BACKGROUND: Endoscopic activity has become a therapeutic endpoint in inflammatory bowel disease. Aim of this study was to evaluate inter-observer agreement for endoscopic scores in a real-life setting. METHODS: 14 gastroenterologists with experience in inflammatory bowel disease care and endoscopic scoring reviewed videos of ulcerative colitis (n=13) and postoperative (n=10) and luminal (n=8) Crohn's disease. The Mayo subscore for ulcerative colitis, Rutgeerts score for postoperative Crohn's disease, Crohn's disease endoscopic index of severity (CDEIS), and the simple endoscopic score-Crohn's disease (SES-CD) for luminal Crohn's disease were calculated. A subset of five endoscopic clips were assessed by 30 general gastroenterologists without specific experience in endoscopic scores. Kappa statistics and intraclass correlation coefficients were used to measure agreement. RESULTS: Mayo subscore agreement was suboptimal: kappas were 0.53 (95% confidence interval 0.47-0.56) and 0.71 (0.67-0.76) for the two groups. Rutgeerts score agreement was fair: kappas were 0.57 (0.51-0.65) and 0.67 (0.60-0.72). Agreements for CDEIS and SES-CD were good: intraclass correlation coefficients for the two groups were 0.83 (0.54-1.00) and 0.67 (0.36-0.97) for CDEIS and 0.93 (0.76-1.00) and 0.68 (0.35-0.97) for SES-CD, respectively. CONCLUSION: The reproducibility of endoscopic scores in inflammatory bowel disease remains suboptimal, which could potentially have major effects on therapeutic choices

Pre-Endoscopy real-time PCR testing for SARS-CoV2 does not reduce health care workers infection and is associated with a higher reduction of endoscopic activity in an outpatient setting

Objective: The role of pre-procedure SARS-CoV2 testing in digestive endoscopy is still debated. AGA guidelines recommend against pre-procedure testing considering low prevalence of SARS-CoV2 infection in the general population and low incidence of infection among endoscopy units Health Care Workers (HCWs). However, no studies have compared pre-procedure testing associated to symptom screening vs. symptom screening alone in reducing the risk of infection for HCWs. Main aim of the present study is to compare the risk of infection for HCWs in different Endoscopy Units adopting different pre-endoscopy screening and operating in two nearby hospital of the same region in Northern Italy in pre-vaccination period. For outpatients in the Endoscopy Unit of Trento (Unit 1) only pre-procedure symptom screening was performed, while in the Endoscopy Unit of Bolzano (Unit 2) pre-procedure symptom screening and negative pre-procedure real-time PCR were requested. Secondary aims were to assess the impact of pre-procedure real-time PCR testing on endoscopic activity and diagnostic delay.Design: Retrospective data collection on a prospectively maintained database was performed, including outpatient endoscopy procedures performed between June 1st 2020 and February 28th 2021 in Unit 1 and Unit 2.Results: No differences in terms of infection rate in HCWs have been identified in Unit 1 and Unit 2 (9.0 vs. 19.3% P=0.2) over a nine-month period. Moreover, in the unit performing pre-procedure real-time PCR before endoscopy a significantly higher reduction in endoscopic activity has been recorded (61.9% vs. 53.4%; P<0.01). In patients with positive real-time PCR, endoscopy was performed with a mean delay of 61.7 days (range 9-294) and 22.5% of them were lost at follow-up and did not undergo any endoscopic procedure in the following 12 months.Conclusions: This study supports the AGA recommendation suggesting that pre-endoscopy real-time PCR is an expensive and time-consuming procedure without proven benefits in an outpatient setting. (Acta gastroenterol. belg., 2022, 85, 581-585)