Antigenic determinants driving serogroup-specific antibody response to Neisseria meningitidis C, W, and Y capsular polysaccharides: Insights for rational vaccine design.

Meningococcal glycoconjugate vaccines sourced from capsular polysaccharides (CPSs) of pathogenic Neisseria meningitidis strains are well-established measures to prevent meningococcal disease. However, the exact structural factors responsible for antibody recognition are not known. CPSs of Neisseria meningitidis serogroups Y and W differ by a single stereochemical center, yet they evoke specific immune responses. Herein, we developed specific monoclonal antibodies (mAbs) targeting serogroups C, Y, and W and evaluated their ability to kill bacteria. We then used these mAbs to dissect structural elements responsible for carbohydrate-protein interactions. First, Men oligosaccharides were screened against the mAbs using ELISA to select putative lengths representing the minimal antigenic determinant. Next, molecular interaction features between the mAbs and serogroup-specific sugar fragments were elucidated using STD-NMR. Moreover, X-ray diffraction data with the anti-MenW CPS mAb enabled the elucidation of the sugar-antibody binding mode. Our findings revealed common traits in the epitopes of all three sialylated serogroups. The minimal binding epitopes typically comprise five to six repeating units. Moreover, the O-acetylation of the neuraminic acid moieties was fundamental for mAb binding. These insights hold promise for the rational design of optimized meningococcal oligosaccharides, opening new avenues for novel production methods, including chemical or enzymatic approaches.

Angioplasty of Dysfunctional Dialysis Fistula or Graft with Resveratrol-Excipient and Paclitaxel-Coated Balloon Improves Primary Patency Rates Compared to Plain Angioplasty Alone.

In this prospective randomized single-blinded study (reg. ISRCTN11414306), 76 patients with a dysfunctional dialysis fistula or graft due to a single de novo or recurrent stenosis in the access circuit were randomized to receive either conventional PTA (POBA) as a standard of care (n = 38) or PTA + adjunctive PTA with a drug-coated (paclitaxel-resveratrol matrix) SeQuent® Please OTW balloon (n = 38, DCB). Patients were scheduled for follow-up PTA at 3, 6, 9, and 12 months. The time of clinically driven target-lesion reintervention rate (primary patency rate) after the index procedure was analyzed using the log-rank test. The primary patency rates at 12 months after the index procedure were 17% (DCB) vs. 11% (POBA). At 3 months, they were 87% vs. 74%, at 6 months they were 53% vs. 26%, and at 9 months they were 22% vs. 11%. The hazard ratio for DCB was 0.55 (95%CI 0.32 to 0.95). The median time needed for target-lesion reintervention was longer in the DCB group (181 days) than in the conventional PTA group (98 days, p = 0.019). We conclude that PTA with the paclitaxel-resveratrol drug-coated SeQuent® Please OTW balloon in patients with de novo or recurrent stenosis in dialysis arteriovenous fistulas or grafts prolongs the time needed for target lesion reintervention and improves primary patency rates in the first year after the index procedure.

Pancreatic Injury in Patients with SARS-Cov-2 (COVID-19) Infection: A Retrospective Analysis of CT Findings.

OBJECTIVE: To determine the association between COVID-19 infection and peripancreatic changes on CT as a sign of acute pancreatic injury. METHODS: Retrospective analysis of CT examinations in patients with confirmed COVID-19 infection yielded 103 instances. An age- and gender-matched cohort of patients without COVID-19 was found. CT examinations were evaluated for peripancreatic stranding or edema, fluid collection, or necrosis, without any other explanation. Depicted pulmonary parenchyma was evaluated for possible COVID-19-related changes. Clinical and laboratory data were retrieved from the clinical database. RESULTS: Peripancreatic fat stranding (n = 8) or fluid collection (n = 2) without any other cause was found in 10 (10%) patients. Abdominal complaints were reported in 4 (40%) patients. Elevated serum amylase or lipase levels were documented in 5 (50%) patients who also satisfied the diagnostic criteria for acute pancreatitis. From the study sample of 103 patients with COVID-19, pulmonary parenchyma was depicted in 102 (99%), and from these, 57 (55%) had an evidence of pulmonary changes compatible with COVID-19 pneumonia. This proportion was not significantly different between patients with and without peripancreatic changes (p = 0.35). In the matched cohort, we found peripancreatic changes in 2 (2%, p = 0.033) patients. Patients with pancreatic injury and elevated amylase levels were more likely to require orotracheal intubation (35% vs. 12%, p = 0.021). CONCLUSIONS: We showed that the prevalence of peripancreatic stranding or fluid collection is higher in patients diagnosed with COVID-19 infection compared to an age- and gender-matched cohort. Patients with pancreatic injury and elevated amylase levels are more likely to require orotracheal intubation. Our findings corroborate the link between COVID-19 infection and pancreatic injury from the perspective of imaging.

Early detection of lung cancer in Czech high-risk asymptomatic individuals (ELEGANCE): A study protocol.

BACKGROUND: Lung cancer screening in high-risk population increases the proportion of patients diagnosed at a resectable stage. AIMS: To optimize the selection criteria and quality indicators for lung cancer screening by low-dose CT (LDCT) in the Czech population of high-risk individuals. To compare the influence of screening on the stage of lung cancer at the time of the diagnosis with the stage distribution in an unscreened population. To estimate the impact on life-years lost according to the stage-specific cancer survival and stage distribution in the screened population. To calculate the cost-effectiveness of the screening program. METHODS: Based on the evidence from large national trials - the National Lung Screening Trial in the USA (NLST), the NELSON study, the recent recommendations of the Fleischner society, the American College of Radiology, and I-ELCAP action group, we developed a protocol for a single-arm prospective study in the Czech Republic for the screening of high-risk asymptomatic individuals. The study commenced in August 2020. RESULTS: The inclusion criteria are: age 55 to 74 years; smoking: ≥30 pack-years; smoker or ex-smoker <15 years; performance status (0-1). The screening timepoints are at baseline and 1 year. The LDCT acquisition has a target CTDIvol ≤0.5mGy and effective dose ≤0.2mSv for a standard-size patient. The interpretation of findings is primarily based on nodule volumetry, volume doubling time (and related risk of malignancy). The management includes follow-up LDCT, contrast enhanced CT, PET/CT, tissue sampling. The primary outcome is the number of cancers detected at a resectable stage, secondary outcomes include the average cost per diagnosis of lung cancer, the number, cost, complications of secondary examinations, and the number of potentially important secondary findings. CONCLUSIONS: A study protocol for early detection of lung cancer in Czech high-risk asymptomatic individuals (ELEGANCE) study using LDCT has been described.

Hybrid and Model-Based Iterative Reconstruction Influences the Volumetry of Visceral and Subcutaneous Adipose Tissue on Ultra-Low-Dose CT.

OBJECTIVE: The aim of this study was to compare three different reconstruction algorithms for the volumetry of the visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) on ultra-low-dose computed tomography (CT) images. METHODS: Thirty-seven male patients underwent ultra-low-dose CT at the level of the fourth lumbar vertebra (22.5 mm in z-axis). The acquisitions were reconstructed in 5-mm slices with 50% overlap using filtered back projection (FBP), hybrid iterative reconstruction (HIR), and iterative model-based reconstruction (IMR) techniques. The volume of VAT and SAT was measured using an interactive seed-growing segmentation and by thresholding (-30 to -190 HU). RESULTS: The volume of SAT measured by the interactive method was smaller in FBP compared with both HIR (P = 0.0011) and IMR (P = 0.0034), and the volume of VAT was greater in IMR compared with HIR (P = 0.0253) or FBP (P = 0.0065). Using the thresholding method, IMR volumes of VAT were greater compared with HIR (P < 0.0001), and volumes of SAT were greater compared with both HIR and FBP (both P ≤ 0.0001). The VAT to SAT ratio was greater in IMR compared with HIR or FBP (both P < 0.0001). CONCLUSIONS: There are significant differences among FBP, HIR, and IMR in the volumetry of SAT and VAT, their ratios, and attenuation measured on ultra-low-dose images.

New coumarin- and phenoxazine-based fluorescent probes for live-cell STED nanoscopy.

The potential of live-cell stimulated emission depletion (STED) nanoscopy has not yet been fully exploited. Currently, the main limitation is the small number of fluorophores and probes that can sustain high light intensity/high dose employed in STED. Namely, fluorophores suitable for STED nanoscopy must be bright and highly photostable and exhibit a large Stokes shift. To expand the list of available probes, we synthesized and evaluated several new membrane probes for live-cell STED nanoscopy. Of the tested probes, probes MePyr500, ThiaCN545 and NB640 not only allow high-resolution STED images, but also partition into the intracellular membranes relatively quickly, thus lacking the selectivity of labelling solely the plasma membrane. During experiments, cytotoxicity was observed merely with the probe ThiaCN545, which blebs the plasma membrane. In comparison with commercially available CellMask Orange and STAR RED (KK114) DPPE, all our tested probes exhibited better photostability with the exception of NB640, which had the fastest bleaching rate of all tested probes. The best overall results can be assigned to the probe MePyr500, providing high-resolution STED images as well as high photostability with no noticeable cytotoxicity, making it an excellent candidate for further development.

Virtual Prototyping and Parametric Design of 3D-Printed Tablets Based on the Solution of Inverse Problem.

The problem of designing tablet geometry and its internal structure that results into a specified release profile of the drug during dissolution was considered. A solution method based on parametric programming, inspired by CAD (computer-aided design) approaches currently used in other fields of engineering, was proposed and demonstrated. The solution of the forward problem using a parametric series of structural motifs was first carried out in order to generate a library of drug release profiles associated with each structural motif. The inverse problem was then solved in three steps: first, the combination of basic structural motifs whose superposition provides the closest approximation of the required drug release profile was found by a linear combination of pre-calculated release profiles. In the next step, the final tablet design was constructed and its dissolution curve found computationally. Finally, the proposed design was 3D printed and its dissolution profile was confirmed experimentally. The computational method was based on the numerical solution of drug diffusion in a boundary layer surrounding the tablet, coupled with erosion of the tablet structure encoded by the phase volume function. The tablets were 3D printed by fused deposition modelling (FDM) from filaments produced by hot-melt extrusion. It was found that the drug release profile could be effectively controlled by modifying the tablet porosity. Custom release profiles were obtained by combining multiple porosity regions in the same tablet. The computational method yielded accurate predictions of the drug release rate for both single- and multi-porosity tablets.

Dynamics of chemotactic droplets in salt concentration gradients.

The chemotactic movement of decanol droplets in aqueous solutions of sodium decanoate in response to concentration gradients of NaCl has been investigated. Key parameters of the chemotactic response, namely the induction time and the migration velocity, have been evaluated as a function of the sodium decanoate concentration and the NaCl concentration gradient. The ability of the decanol droplets to migrate in concentration gradients has been demonstrated not only in a linear chemotactic assay but also in a topologically complex environment. Additionally, the ability to reverse the direction of movement repeatedly, to carry and release a chemically reactive cargo, to select a stronger concentration gradient from two options, and to initiate chemotaxis by an external temperature stimulus have been demonstrated.