The interaction of bacteria with the respiratory mucosa in vitro and in vivo

Using a simple nasopharyngeal organ culture in which the mucosa is exposed to air, this thesis describes the interaction between two piliated and one non-piliated variants of Neisseria meningitidis and the interaction of a pneumolysin sufficient and deficient isogenic variant of Streptococcus pneumoniae with respiratory mucosa. Piliated N. meningitidis adhered more often than the non-piliated variant to the respiratory mucosa and demonstrated tropism for non-ciliated epithelial cells and only rarely adhered to mucus. In contrast, S.pneumoniae demonstrated tropism for mucus. Infection resulted in a change in the appearance of mucus, ciliary beat slowing and epithelial damage. To assess if other bacteria may impair mucociliary clearance by disorganising cilia the effect of pyocyanin, 1-hydroxyphenazine (1-HP) and rhamnolipid on the orientation of human ciliated cells was studied. Pyocyanin and 1-HP at pathophysiological concentrations caused ciliary slowing, dyskinesia and disorientation of the ciliary microtubular pairs. However, the orientation of basal feet did not change. Rhamnolipid at pathophysiologic concentrations caused ciliary slowing but neither dyskinesia or disorientation. Disorientation of ciliary beat as well as slowed CBF may contribute to the slowing of mucociliary clearance in vivo. To assess if ciliary disorientation occurs as an acquired and/or congenital abnormality, groups of patients with chronic upper respiratory tract inflammation due to infection and patients with the clinical features of primary ciliary dyskinesia but normal ciliary beat frequency and ciliary ultrastructure were studied. Ciliary disorientation was associated with slowing of nasomucociliary clearance. The clinical features, ciliary function studies and the ciliary orientation of eleven patients with the classical features of primary ciliary dyskinesia but with normal ciliary ultrastructure were assessed. The results suggests that ciliary disorientation alone does represent a new variant of primary ciliary dyskinesia

Organic phase separation opens up new opportunities to interrogate the RNA-binding proteome.

Protein-RNA interactions regulate all aspects of RNA metabolism and are crucial to the function of catalytic ribonucleoproteins. Until recently, the available technologies to capture RNA-bound proteins have been biased toward poly(A) RNA-binding proteins (RBPs) or involve molecular labeling, limiting their application. With the advent of organic-aqueous phase separation-based methods, we now have technologies that efficiently enrich the complete suite of RBPs and enable quantification of RBP dynamics. These flexible approaches to study RBPs and their bound RNA open up new research avenues for systems-level interrogation of protein-RNA interactions

Genetic Diversity in New Members of the Reticulocyte Binding Protein Family in Thai Plasmodium vivax Isolates

Background Plasmodium vivax merozoites specifically invade reticulocytes. Until recently, two reticulocyte-binding proteins (Pvrbp1 and Pvrbp2) expressed at the apical pole of the P. vivax merozoite were considered to be involved in reticulocyte recognition. The genome sequence recently obtained for the Salvador I (Sal-I) strain of P. vivax revealed additional genes in this family, and in particular Pvrbp2a, Pvrbp2b (Pvrbp2 has been renamed as Pvrbp2c) and two pseudogenes Pvrbp2d and Pvrbp3. It had been previously found that Pvrbp2c is substantially more polymorphic than Pvrbp1. The primary goal of this study was to ascertain the level of polymorphism of these new genes. Methodology/Principal Findings The sequence of the Pvrbp2a, Pvrbp2b, Pvrbp2d and Pvrbp3 genes were obtained by amplification/cloning using DNA purified from four isolates collected from patients that acquired the infection in the four cardinal regions of Thailand (west, north, south and east). An additional seven isolates from western Thailand were analyzed for gene copy number variation. There were significant polymorphisms exhibited by these genes (compared to the reference Sal-I strain) with the ratio of mutations leading to a non-synonymous or synonymous amino acid change close to 3∶1 for Pvrbp2a and Pvrbp2b. Although the degree of polymorphism exhibited by these two genes was higher than that of Pvrbp1, it did not reach the exceptional diversity noted for Pvrbp2c. It was interesting to note that variations in the copy number of Pvrbp2a and Pvrbp2b occurred in some isolates. Conclusions/Significance The evolution of different members of the Pvrbp2 family and their relatively high degree of polymorphism suggests that the proteins encoded by these genes are important for parasite survival and are under immune selection. Our data also shows that there are highly conserved regions in rbp2a and rbp2b, which might provide suitable targets for future vaccine development against the blood stage of P. vivax

Does Manual Therapy Provide Additional Benefit To Breathing Retraining In The Management Of Dysfunctional Breathing? A Randomised Controlled Trial

Purpose: Dysfunctional breathing (DB) is associated with an abnormal breathing pattern, unexplained breathlessness and significant patient morbidity. Treatment involves breathing retraining through respiratory physiotherapy. Recently, manual therapy (MT) has also been used, but no evidence exists to validate its use. This study sought to investigate whether MT produces additional benefit when compared with breathing retraining alone in patients with DB. Methods: Sixty subjects with primary DB were randomised into either breathing retraining (standard treatment; n¼30) or breathing retraining plus MT (intervention; n¼30) group. Both the groups received standardised respiratory physiotherapy, which included: DB education, breathing retraining, home regimen, and audio disc. Intervention group subjects additionally received MT following further assessment. Data from 57 subjects were analysed. Results: At baseline, standard treatment group subjects were statistically younger (41.7 + 13.5 versus 50.8 + 13.0 years; p¼0.001) with higher Nijmegen scores (38.6 + 9.5 versus 31.5 + 6.9; p¼0.001). However, no significant difference was found between the groups for primary outcome Nijmegen score (95% CI ( 1.1, 6.6) p¼0.162), or any secondary outcomes (Hospital Anxiety & Depression Score, spirometry or exercise tolerance). Conclusion: Breathing retraining is currently the mainstay of treatment for patients with DB. The results of this study suggest MT provides no additional benefit in this patient group.Juliana Burgess, Dr Robert Wilson, Royal Brompton & Harefield NHS Foundation Trust, and Dr Andy Jones fo

Determination of the Pharmacokinetics and Pharmacodynamics of Isoniazid, Rifampicin, Pyrazinamide and Ethambutol in a Cross-Over Cynomolgus Macaque Model of Mycobacterium tuberculosis Infection

Innovative cross-over study designs were explored in non-human primate (NHP) studies to determine the value of this approach for the evaluation of drug efficacy against tuberculosis (TB). Firstly, the pharmacokinetics (PK) of each of the drugs Isoniazid (H), Rifampicin (R), Pyrazinamide (Z) and Ethambutol (E), that are standardly used for the treatment of tuberculosis, was established in the blood of macaques after oral dosing as a monotherapy or in combination. Two studies were conducted to evaluate the pharmacokinetics and pharmacodynamics of different drug combinations using cross-over designs. The first employed a balanced, three-period Pigeon design with an extra period; this ensured that treatment by period interactions and carry-over could be detected comparing the treatments HR, HZ and HRZ using H37Rv as the challenge strain of Mycobacterium tuberculosis (M. tb). Although the design accounted for considerable variability between animals, the three regimens evaluated could not be distinguished using any of the alternative endpoints assessed. However, the degree of pathology achieved using H37Rv in the model during this study was less than expected. Based on these findings, a second experiment using a classical AB/BA design comparing HE with HRZ was conducted using the M. tb Erdman strain. More extensive pathology was observed, and differences in computerized tomography (CT) scores and bacteriology counts in the lungs were detected, although due to the small group sizes, clearer differences were not distinguished. Type 1 T helper (Th1) cell response profiles were characterized using the IFN-γ ELISPOT assay and revealed differences between drug treatments that corresponded to decreases in disease burden. Therefore, the studies performed support the utility of the NHP model for the determination of PK/PD of TB drugs, although further work is required to optimize the use of cross-over study designs

Associations between depressive symptoms and disease progression in older patients with chronic kidney disease: results of the EQUAL study

Background Depressive symptoms are associated with adverse clinical outcomes in patients with end-stage kidney disease; however, few small studies have examined this association in patients with earlier phases of chronic kidney disease (CKD). We studied associations between baseline depressive symptoms and clinical outcomes in older patients with advanced CKD and examined whether these associations differed depending on sex. Methods CKD patients (>= 65 years; estimated glomerular filtration rate <= 20 mL/min/1.73 m(2)) were included from a European multicentre prospective cohort between 2012 and 2019. Depressive symptoms were measured by the five-item Mental Health Inventory (cut-off <= 70; 0-100 scale). Cox proportional hazard analysis was used to study associations between depressive symptoms and time to dialysis initiation, all-cause mortality and these outcomes combined. A joint model was used to study the association between depressive symptoms and kidney function over time. Analyses were adjusted for potential baseline confounders. Results Overall kidney function decline in 1326 patients was -0.12 mL/min/1.73 m(2)/month. A total of 515 patients showed depressive symptoms. No significant association was found between depressive symptoms and kidney function over time (P = 0.08). Unlike women, men with depressive symptoms had an increased mortality rate compared with those without symptoms [adjusted hazard ratio 1.41 (95% confidence interval 1.03-1.93)]. Depressive symptoms were not significantly associated with a higher hazard of dialysis initiation, or with the combined outcome (i.e. dialysis initiation and all-cause mortality). Conclusions There was no significant association between depressive symptoms at baseline and decline in kidney function over time in older patients with advanced CKD. Depressive symptoms at baseline were associated with a higher mortality rate in men