Structural analysis of the O-acetylated O-polysaccharide isolated from Salmonella Paratyphi A and used for vaccine preparation

Salmonella paratyphi A is increasingly recognized as a common cause of enteric fever cases and there are no licensed vaccines against this infection. Antibodies directed against the O-polysaccharide of the lipopolysaccharide of Salmonella are protective and conjugation of the O-polysaccharide to a carrier protein represents a promising strategy for vaccine development. O-Acetylation of S. paratyphi A O-polysaccharide is considered important for the immunogenicity of S. paratyphi A conjugate vaccines. Here, as part of a programme to produce a bivalent conjugate vaccine against both S. typhi and S. paratyphi A diseases, we have fully elucidated the O-polysaccharide structure of S. paratyphi A by use of HPLC\u2013SEC, HPAEC\u2013PAD/CD, GLC, GLC\u2013MS, 1D and 2D-NMR spectroscopy. In particular, chemical and NMR studies identified the presence of O-acetyl groups on C-2 and C-3 of rhamnose in the lipopolysaccharide repeating unit, at variance with previous reports of O-acetylation at a single position. Moreover HR-MAS NMR analysis performed directly on bacterial pellets from several strains of S. paratyphi A also showed O-acetylation on C-2 and C-3 of rhamnose, thus this pattern is common and not an artefact from O-polysaccharide purification. Conjugation of the O-polysaccharide to the carrier protein had little impact on O-acetylation and therefore should not adversely affect the immunogenicity of the vaccine

Gold nanoparticles approach to detect chondroitin sulphate and hyaluronic acid urothelial coating

This study investigated the location of hyaluronic acid (HA)-and chondroitin sulphate (CS)-coated gold nanoparticles in rabbit bladder and evaluated gene expression of CD44, RHAMM and ICAM-1 receptors involved in HA and CS transport into the cell. Gold nanoparticles were synthesised by reduction of gold salts with HA or CS to form HA-AuNPs and CS-AuNPs. Bladder samples were incubated with CS-AuNPs and HA-AuNPs or without glycosaminoglycans. Transmission electron microscopy, optic microscopy and scanning electron microscopy were used to determine the location of the synthesised AuNPs. Real-time PCR was used to analyse expression of urothelial cell receptors CD44, RHAMM, ICAM-1, after ex vivo administration of CS-AuNPs and HA-AuNPs. We showed that HA-AuNPs and CS-AuNPs were located in the cytoplasm and tight junctions of urothelial umbrella cells; this appearance was absent in untreated bladders. There were no significant differences in gene expression levels for CD44, RHAMM and ICAM-1 receptors in treated versus control bladder tissues. In conclusion, we clearly showed the presence of exogenous GAGs in the bladder surface and the tight junctions between umbrella cells, which is important in the regeneration pathway of the urothelium. The GAGs-AuNPs offer a promising approach to understanding the biophysical properties and imaging of urothelial tissue

Impact of the time interval between primary or interval surgery and adjuvant chemotherapy in ovarian cancer patients

Introduction: Primary debulking surgery (PDS), interval debulking surgery (IDS), and platinum-based chemotherapy are the current standard treatments for advanced ovarian cancer (OC). The time to initiation of adjuvant chemotherapy (TTC) could influence patient outcomes. Methods: We conducted a multicenter retrospective cohort study of advanced (International Federation of Gynecology and Obstetrics (FIGO) stage III or IV) OC treated between 2014 and 2018 to assess progression-free survival (PFS) and overall survival (OS) in relation to TTC. All patients underwent a germline multigene panel for BRCA1/2 evaluation. Results: Among the 83 patients who underwent PDS, a TTC ≥ 60 days was associated with a shorter PFS (hazard ratio (HR) 2.02, 95% confidence interval (CI) 1.04–3.93, p = 0.038), although this association lost statistical significance when adjusting for residual disease (HR 1.52, 95% CI 0.75–3.06, p = 0.244, for TTC and HR 2.73, 95% CI 1.50–4.96, p = 0.001, for residual disease). Among 52 IDS patients, we found no evidence of an association between TTC and clinical outcomes. Ascites, type of chemotherapy, or germline BRCA1/2 mutational status did not influence TTC and were not associated with clinical outcomes in PDS or IDS patients. Discussion: In conclusion, longer TTC seems to negatively affect prognosis in patients undergoing PDS, especially those with residual disease

Metabolic effects of bezafibrate in mitochondrial disease.

Funder: Medical Research Council (MRC): Confidence in Concept award to Newcastle UniversityMitochondrial disorders affect 1/5,000 and have no cure. Inducing mitochondrial biogenesis with bezafibrate improves mitochondrial function in animal models, but there are no comparable human studies. We performed an open-label observational experimental medicine study of six patients with mitochondrial myopathy caused by the m.3243A>G MTTL1 mutation. Our primary aim was to determine the effects of bezafibrate on mitochondrial metabolism, whilst providing preliminary evidence of safety and efficacy using biomarkers. The participants received 600-1,200 mg bezafibrate daily for 12 weeks. There were no clinically significant adverse events, and liver function was not affected. We detected a reduction in the number of complex IV-immunodeficient muscle fibres and improved cardiac function. However, this was accompanied by an increase in serum biomarkers of mitochondrial disease, including fibroblast growth factor 21 (FGF-21), growth and differentiation factor 15 (GDF-15), plus dysregulation of fatty acid and amino acid metabolism. Thus, although potentially beneficial in short term, inducing mitochondrial biogenesis with bezafibrate altered the metabolomic signature of mitochondrial disease, raising concerns about long-term sequelae

Impact of conjugation chemistry on the immunogenicity of S. Typhimurium conjugate vaccines

: Salmonella Typhimurium is major cause of invasive nontyphoidal Salmonella disease in Africa. Conjugation of S. Typhimurium O-antigen to an appropriate carrier protein constitutes a possible strategy for the development of a vaccine against this disease, for which no vaccines are currently available. The conjugation chemistry used is one of the parameters that can affect the immunogenicity of glycoconjugate vaccines. Herein different glycoconjugates were synthesized to investigate the impact of this variable on the immunogenicity of S. Typhimurium conjugate vaccines in mice, all with CRM₁₉₇ as carrier protein. Random derivatization along the O-antigen chain was compared with site-directed activation of the terminal KDO sugar residue of the core oligosaccharide. In particular, two different random approaches were used, based on the oxidation of the polysaccharide, which differently impact the structure and conformation of the O-antigen chain. For the selective conjugation methods, linkers of two different lengths were compared. When tested in mice, all conjugates induced anti-O-antigen IgG antibodies with serum bactericidal activity. Similar anti-O-antigen antibody levels were elicited independent of the chemistry used and a higher degree of saccharide derivatization did not impact negatively on the anti-O-antigen IgG response. Bactericidal activity of serum antibodies induced by selective conjugates was similar independent of the length of the spacer used. Random conjugates elicited antibodies with greater bactericidal activity than selective ones, and an inverse correlation was found between degree of O-antigen modification and antibody functional activity

The prognostic legacy of left ventricular hypertrophy: cumulative evidence after the MAVI study

Objective: Although regression of left ventricular hypertrophy (LVH) confers a marked prognostic benefit, it is unknown whether cardiovascular risk in these patients is comparable to those who never developed LVH. Methods: We analyzed the 'Massa Ventricolare sinistra nell'Ipertensione' (MAVI) study, a prospective study in which serial changes in left ventricular mass at echocardiography were associated with subsequent cardiovascular events. We also conducted a cumulative meta-analysis in order to investigate how evidence progressed in this field. We defined three phenotypes: persistently normal left ventricular mass; LVH regression; persistence/new development of LVH. Results: Left ventricular mass was measured at baseline and 2 years after the initial assessment in 374 patients (64% women). Clinical outcomes were ascertained after the 2-year echocardiographic evaluation (mean follow-up 3.2 years). Persistence or new development of LVH was associated with an increased risk of cardiovascular events (odds ratio 1.96, 95% confidence interval 1.07-3.57, P0.029). In a cumulative meta-analyses that included MAVI and six comparable studies for a total of 2954 patients and 339 cardiovascular events, when a persistently normal left ventricular mass was taken as reference, regression of LVH was associated with 56% higher risk of cardiovascular events (odds ratio 1.56, 95% confidence interval 1.04-2.36, absolute risk increase 3%, P0.033). Conversely, evidence accrued from previous studies that persistence or new development of LVH predicts an adverse outcome did not change after MAVI. Conclusions: Cardiovascular risk is higher in patients with LVH regression than in those with persistently normal left ventricular mass. Preventing development of LVH is thus an important target