Structure-Based Discovery of Lipoteichoic Acid Synthase Inhibitors

Lipoteichoic acid synthase (LtaS) is a key enzyme for the cell wall biosynthesis of Gram-positive bacteria. Gram-positive bacteria that lack lipoteichoic acid (LTA) exhibit impaired cell division and growth defects. Thus, LtaS appears to be an attractive antimicrobial target. The pharmacology around LtaS remains largely unexplored with only two small-molecule LtaS inhibitors reported, namely "compound 1771" and the Congo red dye. Structure-based drug discovery efforts against LtaS remain unattempted due to the lack of an inhibitor-bound structure of LtaS. To address this, we combined the use of a molecular docking technique with molecular dynamics (MD) simulations to model a plausible binding mode of compound 1771 to the extracellular catalytic domain of LtaS (eLtaS). The model was validated using alanine mutagenesis studies combined with isothermal titration calorimetry. Additionally, lead optimization driven by our computational model resulted in an improved version of compound 1771, namely, compound 4 which showed greater affinity for binding to eLtaS than compound 1771 in biophysical assays. Compound 4 reduced LTA production in S. aureus dose-dependently, induced aberrant morphology as seen for LTA-deficient bacteria, and significantly reduced bacteria titers in the lung of mice infected with S. aureus. Analysis of our MD simulation trajectories revealed the possible formation of a transient cryptic pocket in eLtaS. Virtual screening (VS) against the cryptic pocket led to the identification of a new class of inhibitors that could potentiate β-lactams against methicillin-resistant S. aureus. Our overall workflow and data should encourage further drug design campaign against LtaS. Finally, our work reinforces the importance of considering protein conformational flexibility to a successful VS endeavor.

A systematic scoping review of multidisciplinary cancer team and decision-making in the management of men with advanced prostate cancer

PURPOSE

The early diagnosis of prostate cancer and subsequent access to the treatment options helps to achieve optimal cancer outcomes. As the treatment options for patients with advanced prostate cancer continues to evolve, patients need to access a multidisciplinary team (MDT) meeting to receive best-practice care.

METHODS

In this paper a MEDLINE review was performed to assess clinical decision making in the context of MDT discussions for patients with advanced prostate cancer.

RESULTS

From 441 returned articles and abstracts, 50 articles were assessed for eligibility and 16 articles included for analysis. Sixteen articles were identified, 9 of the 16 articles used quantitative methodology including three retrospective analysis of clinical registry data, patient medical records and/or MDT meeting notes and three cross-sectional surveys. Other study designs included one observation study and one study using a combination of qualitative and quantitative methodologies and one mini-review. There were also four editorials included in the review and two consensus statements.

CONCLUSION

This paper highlights the important role the inter-disciplinary MDT has on shared decision making for men with advanced prostate cancer. The application of MDT care is a rapidly growing trend in uro-oncology and an efficient MDT service requires further research to assess its efficiency so that it may expand through all aspect of uro-oncology.

PSMA PET applications in the prostate cancer journey: from diagnosis to theranostics

The heterogeneity of prostate cancer has made imaging modalities of crucial importance in this disease. Accurate diagnosis and staging of the volume and extent of disease, especially in advanced and metastatic prostate cancer, can help to tailor the timing and modalities of treatment. While MRI has been effective in the detection of significant prostate cancer, its use in the identification and quantification of extraprostatic disease is limited. This gap is now being filled by PSMA PET. PSMA PET scans have now been shown to have a role in all stages in the prostate cancer journey. Emerging evidence has shown its promise in primary staging, restaging and theranostics. In this paper, we review the evidence for the use of PSMA PET in the various stages of prostate cancer, from initial diagnosis to advanced metastatic disease where other systemic treatments have failed.

Echocardiographic predictors of adverse clinical events in children with dilated cardiomyopathy: a prospective clinical study

OBJECTIVES

To compare tissue Doppler (TD) velocities between patients with dilated cardiomyopathy (DCM) and normal controls and to determine whether TD velocities, Tei index, right ventricular fractional area change, and left ventricular ejection fraction (LVEF) predict adverse clinical outcomes in children with DCM.

METHODS

Prospective evaluation of children with DCM.

RESULTS

54 children with DCM and 54 age and sex matched control group participants were studied. Mitral inflow velocities were similar for both groups except for decreased mitral deceleration time in patients with DCM. Systolic and diastolic TD velocities at the mitral annulus (septal and lateral sides) and tricuspid annulus were significantly reduced in children with DCM compared with controls (p < 0.001 for each). By multivariate analysis, after adjustment for Tei index and right ventricular fractional area change, decreased LVEF and tricuspid velocity during early diastole (Ea) were predictors of the primary end point (PEP), a composite end point consisting of need for hospitalisation or the outcome transplantation or death. Tricuspid Ea velocity < 8.5 cm/s had 87% specificity and 60% sensitivity for reaching the PEP. LVEF < 30% had 68% specificity and 74% sensitivity for the PEP. Combined LVEF < 30% and tricuspid Ea < 11.5 cm/s had 100% specificity and 44% sensitivity for the PEP.

CONCLUSIONS

Children with DCM have significantly lower TD velocities than normal controls. In such cases, lower LVEF (< 30%) is more sensitive but less specific than lower tricuspid Ea velocities (< 8.5 cm/s) in predicting which patients are at risk of hospitalisation, transplantation, or death.

Effect of prenatal diagnosis of critical left heart obstruction on perinatal morbidity and mortality

We sought to determine the effect of prenatal diagnosis of congenital heart disease, specifically critical left heart obstructive (LHO) lesions, on postnatal morbidity and mortality. Several studies have found no significant improvement in mortality in infants with prenatally detected heart disease compared to infants diagnosed postnatally. Few reports have focused on the specific effects of prenatal diagnosis on the perinatal course. All newborns with LHO seen between July 1993 and July 1996 were identified and divided into two groups based on prenatal vs. postnatal diagnosis. Hospital records were reviewed for demographic and outcome variables. The outcome variables included degree of metabolic acidosis, hemodynamic instability, noncardiac organ dysfunction, delayed surgical intervention, and surgical mortality. Twenty-three fetuses were diagnosed with LHO lesions. Postnatally, 45 newborns presented with LHO anomalies. Prenatal diagnosis resulted in avoidance of hemodynamic compromise, reduced organ dysfunction, and reduced surgical delays. There was no significant difference in surgical mortality. Prenatal diagnosis significantly decreases postnatal morbidity in infants with LHO lesions. Although surgical results are similar, the reduced morbidity decreases surgical delays and potentially may impact on neurodevelopmental outcomes.