Identification of complex III, NQR, and SDH as primary bioenergetic enzymes during the stationary phase of Pseudomonas aeruginosa cultured in urine-like conditions

Pseudomonas aeruginosa is a common cause of urinary tract infections by strains that are often multidrug resistant, representing a major challenge to the world's health care system. This microorganism has a highly adaptable metabolism that allows it to colonize many environments, including the urinary tract. In this work, we have characterized the metabolic strategies used by stationary phase P. aeruginosa cells cultivated in urine-like media to understand the adaptations used by this microorganism to survive and produce disease. Our proteomics results show that cells rely on the Entner-Duodoroff pathway, pentose phosphate pathway, the Krebs cycle/ glyoxylate shunt and the aerobic oxidative phosphorylation to survive in urine-like media and other conditions. A deep characterization of the oxidative phosphorylation showed that the respiratory rate of stationary phase cells is increased 3-4 times compared to cells in the logarithmic phase of growth, indicating that the aerobic metabolism plays critical roles in the stationary phase of cells grown in urine like media. Moreover, the data show that respiratory complex III, succinate dehydrogenase and the NADH dehydrogenase NQR have important functions and could be used as targets to develop new antibiotics against this bacterium.

Breast-to-brain metastasis is exacerbated with chemotherapy through blood-cerebrospinal fluid barrier and induces Alzheimer's-like pathology

Control of breast-to-brain metastasis remains an urgent unmet clinical need. While chemotherapies are essential in reducing systemic tumor burden, they have been shown to promote non-brain metastatic invasiveness and drug-driven neurocognitive deficits through the formation of neurofibrillary tangles (NFT), independently. Now, in this study, we investigated the effect of chemotherapy on brain metastatic progression and promoting tumor-mediated NFT. Results show chemotherapies increase brain-barrier permeability and facilitate enhanced tumor infiltration, particularly through the blood-cerebrospinal fluid barrier (BCSFB). This is attributed to increased expression of matrix metalloproteinase 9 (MMP9) which, in turn, mediates loss of Claudin-6 within the choroid plexus cells of the BCSFB. Importantly, increased MMP9 activity in the choroid epithelium following chemotherapy results in cleavage and release of Tau from breast cancer cells. This cleaved Tau forms tumor-derived NFT that further destabilize the BCSFB. Our results underline for the first time the importance of the BCSFB as a vulnerable point of entry for brain-seeking tumor cells post-chemotherapy and indicate that tumor cells themselves contribute to Alzheimer's-like tauopathy.

NFL strongly correlates with TNF-R1 in the plasma of AD patients, but not with cognitive decline

Peripheral inflammation mechanisms involved in Alzheimer's disease (AD) have yet to be accurately characterized and the identification of blood biomarker profiles could help predict cognitive decline and optimize patient care. Blood biomarkers described to date have failed to provide a consensus signature, which is mainly due to the heterogeneity of the methods used or the cohort. The present work aims to describe the potential informativity of peripheral inflammation in AD, focusing in particular on the potential association between the level of plasma neurofilament light (NFL), peripheral inflammation (by quantifying IL-1β, IL-6, TNFα, CCL5, TNF-R1, sIL-6R, TIMP-1, IL-8 in blood) and cognitive decline (assessed by the MMSE and ADAScog scales) through a 2-year follow-up of 40 AD patients from the Cytocogma cohort (CHU Poitiers, Pr M. Paccalin). Our results show for the first time a strong correlation between plasma NFL and TNF-R1 at each time of follow-up (baseline, 12 and 24 months), thus opening an interesting perspective for the prognosis of AD patients.

Enabling silicon-on-silicon photonics with pedestalled Mie resonators

High-refractive-index Mie resonators are regarded as promising building blocks for low-loss all-dielectric nanophotonic applications. To avoid the otherwise excessive damping and loss of symmetry such devices typically need to be implemented over a low-index substrate, which hampers their integration in many practical applications. In this paper we propose a new photonic structure consisting of silicon-on-silicon spheroidal-like resonators, each one supported by a slim silicon pedestal that makes the micro-cavities stand optically separated from the substrate while providing both mechanical stability and electrical contact with the substrate. These structures are produced in high-quality monocrystalline Si and their size and arrangement can be precisely controlled through standard lithography. We demonstrate that such structures present an optical performance similar to the one achieved with low-index substrates, opening new avenues for developing novel hybrid photonic/electronic devices.

Value of PET/CT 3D visualization of head and neck squamous cell carcinoma extended to mandible

PURPOSE

To study an original 3D visualization of head and neck squamous cell carcinoma extending to the mandible by using [18F]-NaF PET/CT and [18F]-FDG PET/CT imaging along with a new innovative FDG and NaF image analysis using dedicated software. The main interest of the 3D evaluation is to have a better visualization of bone extension in such cancers and that could also avoid unsatisfying surgical treatment later on.

PATIENTS AND METHODS

A prospective study was carried out from November 2016 to September 2017. Twenty patients with head and neck squamous cell carcinoma extending to the mandible (stage 4 in the UICC classification) underwent [18F]-NaF and [18F]-FDG PET/CT. We compared the delineation of 3D quantification obtained with [18F]-NaF and [18F]-FDG PET/CT. In order to carry out this comparison, a method of visualisation and quantification of PET images was developed. This new approach was based on a process of quantification of radioactive activity within the mandibular bone that objectively defined the significant limits of this activity on PET images and on a 3D visualization. Furthermore, the spatial limits obtained by analysis of the PET/CT 3D images were compared to those obtained by histopathological examination of mandibular resection which confirmed intraosseous extension to the mandible.

RESULTS

The [18F]-NaF PET/CT imaging confirmed the mandibular extension in 85% of cases and was not shown in [18F]-FDG PET/CT imaging. The [18F]-NaF PET/CT was significantly more accurate than [18F]-FDG PET/CT in 3D assessment of intraosseous extension of head and neck squamous cell carcinoma. This new 3D information shows the importance in the imaging approach of cancers. All cases of mandibular extension suspected on [18F]-NaF PET/CT imaging were confirmed based on histopathological results as a reference.

CONCLUSIONS

The [18F]-NaF PET/CT 3D visualization should be included in the pre-treatment workups of head and neck cancers. With the use of a dedicated software which enables objective delineation of radioactive activity within the bone, it gives a very encouraging results. The [18F]-FDG PET/CT appears insufficient to confirm mandibular extension. This new 3D simulation management is expected to avoid under treatment of patients with intraosseous mandibular extension of head and neck cancers. However, there is also a need for a further study that will compare the interest of PET/CT and PET/MRI in this indication.

[Relapse of acute promyelocytic leukemia in the central nervous system revealed by isolated dementia]

INTRODUCTION

Approximately 1.5% of dementia is due to curable aetiology. We report an isolated dementia syndrome due to a meningeal relapse of acute promyelocytic leukaemia with favourable outcome after appropriate treatment.

CASE REPORT

A 72-year-old woman, in remission of an acute promyelocytic leukaemia, presented a loss of autonomy for several months due to corticosubcortical dementia. Lumbar puncture showed blast cells indicating meningeal relapse of leukaemia. Intrathecal chemotherapy and arsenic trioxide obtained biological and molecular remission as well as restoration of normal cognitive functions.

CONCLUSION

In patients with hematologic past history such as acute promyelocytic leukaemia, an isolated cognitive impairment should alert physicians to search for an isolated neuromeningeal relapse.

Diffuse pulmonary uptake on FDG-PET with normal CT diagnosed as intravascular large B-cell lymphoma: a case report and a discussion of the causes of diffuse FDG uptake in the lungs

A 71-year-old woman was admitted to our hospital with asthenia, weight loss, fever, cognitive impairment and shortness of breath. Physical examination showed hemiparesis and cerebellar ataxia. There was no superficial lymphadenopathy. Blood tests showed raised levels of C-reactive protein and lactate dehydrogenase. Bone marrow aspiration and biopsy were negative. [¹⁸F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) showed intense uptake within a right apical nodule and intense and diffuse uptake of FDG in the lungs without corresponding structural CT abnormality. Lung biopsy showed intravascular large B-cell lymphoma (IVLBCL). FDG-PET findings in IVLBCL and causes of diffuse FDG lung uptake with and without CT abnormalities are discussed.

Fluorodeoxyglucose positron emission tomography fails to detect distant metastases at initial staging of melanoma patients with metastatic involvement of sentinel lymph node

BACKGROUND

Positron emission tomography (PET) using fluorodeoxyglucose (FDG) has proven to be more sensitive and accurate than other imaging modalities for the detection of distant metastases in patients with melanoma. Sentinel lymph node (SLN) status is the most important prognostic factor in melanoma patients with no evidence of distant metastasis.

OBJECTIVES

To assess the rate of distant metastases in patients with a positive SLN biopsy (SLNB).

METHODS

Forty-six consecutive patients with a positive SLNB underwent PET or PET-computed tomography within 6 weeks of the SLNB procedure. The patients did not present any clinical sign of nodal involvement or of distant metastasis. PET findings were classified as positive, negative or nonconclusive.

RESULTS

No patient had a positive PET scan for distant metastasis. Six patients (13%) had a nonconclusive PET scan; none of them presented distant metastasis within 12 months. Forty patients (87%) had a negative PET scan; among them five (12%) presented with distant metastasis within 12 months.

CONCLUSIONS

Fluorodeoxyglucose positron emission tomography failed to detect distant metastases at initial staging in patients with a positive SLNB, even in patients who presented with distant metastases within 12 months after the FDG PET scan. These results could be explained by the low prevalence of macroscopic metastatic disease at this stage and by the important delay between the onset of the spread of microscopic metastatic disease and the identification by PET scan of macroscopic metastatic disease.

A comparison of the polymerase chain reaction with standard laboratory methods for the detection of EHV-1 and EHV-4 in archival tissue samples

A detection system incorporating the polymerase chain reaction was compared with the use of histopathology and virus isolation to determine the presence of equid herpesvirus type 1 or equid herpesvirus type 4 in equine tissues submitted to a diagnostic laboratory. When the polymerase chain reaction was performed, these tissues had been stored for up to 3 years. Thirty-eight tissues representing 14 cases had been stored embedded in paraffin wax. Analysis of these tissues using the PCR gave predictive values of 1.0 and 0.91 for a positive and negative result respectively, and sensitivity and specificity values of 75% and 100% respectively. Fifty-three tissues representing 28 cases had been stored immersed in 10% formalin. Analysis of these tissues gave predictive values of 0.44 and 0.42 for a positive and negative result respectively, and sensitivity and specificity values of 28% and 57% respectively. The poor results obtained with this group of tissues was attributed to contamination of the samples during wax embedding. Viral DNA could not be amplified from older tissues. These results indicate that under appropriate conditions the polymerase chain reaction is reliable when applied to tissues collected for routine diagnosis. However, it is less reliable when samples for analysis are handled collectively. Also, storage of tissues in wax blocks for 14 or more years inhibits later amplification of viral DNA from these tissues. The implications of these results to the application of the polymerase chain reaction to routine laboratory diagnosis are discussed.