Autonomous robotic intracardiac catheter navigation using haptic vision

International audienceWhile all minimally invasive procedures involve navigating from a small incision in the skin to the site of the intervention, it has not been previously demonstrated how this can be done 10 autonomously. To show that autonomous navigation is possible, we investigated it in the hardest place to do it-inside the beating heart. We created a robotic catheter that can navigate through the blood-filled heart using wall-following algorithms inspired by positively thigmotactic animals. The catheter employs haptic vision, a hybrid sense using imaging for both touch-based surface identification and force sensing, to accomplish wall following inside the blood-filled heart. 15 Through in vivo animal experiments, we demonstrate that the performance of an autonomously-controlled robotic catheter rivals that of an experienced clinician. Autonomous navigation is a fundamental capability on which more sophisticated levels of autonomy can be built, e.g., to perform a procedure. Similar to the role of automation in fighter aircraft, such capabilities can free the clinician to focus on the most critical aspects of the procedure while providing precise and 20 repeatable tool motions independent of operator experience and fatigue

Molecular lymph node staging with one-step nucleic acid amplification and its prognostic value for patients with colon cancer: the first follow-up study

Background Molecular lymph node workup with one-step nucleic acid amplification (OSNA) is a validated diagnostic adjunct in breast cancer and also appealing for colon cancer (CC) staging. This study, for the first time, evaluates the prognostic value of OSNA in CC. Patients and methods The retrospective study includes patients with stage I-III CC from three centres. Lymph nodes were investigated with haematoxylin and eosin (H&E) and with OSNA, applying a 250 copies/mu L threshold of CK19 mRNA. Diagnostic value of H&E and OSNA was assessed by survival analysis, sensitivity, specificity and time-dependent receiver operating characteristic curves. Results Eighty-seven patients were included [mean follow-up 53.4 months (+/- 24.9)]. Disease recurrence occurred in 16.1% after 19.8 months (+/- 12.3). Staging with H&E independently predicted worse cancer-specific survival in multivariate analysis (HR = 10.77, 95% CI 1.07-108.7, p = 0.019) but not OSNA (HR = 3.08, 95% CI 0.26-36.07, p = 0.197). With cancer-specific death or recurrence as gold standard, H&E sensitivity was 46.7% (95% CI 21.3-73.4%) and specificity 84.7% (95% CI 74.3-92.1%). OSNA sensitivity and specificity were 60.0% (95% CI 32.3-83.7%) and 75.0% (95% CI 63.4-84.5%), respectively. Conclusions In patients with CC, OSNA does not add relevant prognostic value to conventional H&E contrasting findings in other cancers. Further studies should assess lower thresholds for OSNA (< 250 copies/mu L).Surgical oncolog

Protein and RNA ADP-ribosylation detection is influenced by sample preparation and reagents used

The modification of substrates with ADP-ribose (ADPr) is im-portant in, for example, antiviral immunity and cancer. Recently, several reagents were developed to detect ADP-ribosylation; however, it is unknown whether they recognise ADPr, specific amino acid-ADPr linkages, or ADPr with the surrounding protein backbone. We first optimised methods to prepare extracts con-taining ADPr-proteins and observe that depending on the amino acid modified, the modification is heatlabile. We tested the re-activity of available reagents with diverse ADP-ribosylated pro-tein and RNA substrates and observed that not all reagents are equally suited for all substrates. Next, we determined cross -reactivity with adenylylated RNA, AMPylated proteins, and me-tabolites, including NADH, which are detected by some reagents. Lastly, we analysed ADP-ribosylation using confocal microscopy, where depending on the fixation method, either mitochondrion, nucleus, or nucleolus is stained. This study allows future work dissecting the function of ADP-ribosylation in cells, both on protein and on RNA substrates, as we optimised sample prepa-ration methods and have defined the reagents suitable for specific methods and substrates.Bio-organic Synthesi

Biallelic Mutations in ADPRHL2, Encoding ADP-Ribosylhydrolase 3, Lead to a Degenerative Pediatric Stress-Induced Epileptic Ataxia Syndrome.

ADP-ribosylation, the addition of poly-ADP ribose (PAR) onto proteins, is a response signal to cellular challenges, such as excitotoxicity or oxidative stress. This process is catalyzed by a group of enzymes referred to as poly(ADP-ribose) polymerases (PARPs). Because the accumulation of proteins with this modification results in cell death, its negative regulation restores cellular homeostasis: a process mediated by poly-ADP ribose glycohydrolases (PARGs) and ADP-ribosylhydrolase proteins (ARHs). Using linkage analysis and exome or genome sequencing, we identified recessive inactivating mutations in ADPRHL2 in six families. Affected individuals exhibited a pediatric-onset neurodegenerative disorder with progressive brain atrophy, developmental regression, and seizures in association with periods of stress, such as infections. Loss of the Drosophila paralog Parg showed lethality in response to oxidative challenge that was rescued by human ADPRHL2, suggesting functional conservation. Pharmacological inhibition of PARP also rescued the phenotype, suggesting the possibility of postnatal treatment for this genetic condition

Intracellular pHluorin as Sensor for Easy Assessment of Bacteriocin-Induced Membrane-Damage in Listeria monocytogenes

Bacteriocins are antimicrobial peptides naturally produced by many bacteria and were shown to be effective against various pathogens including Listeria monocytogenes. L. monocytogenes is a food-borne pathogen that frequently causes disease outbreaks around the world with fatal outcomes in at-risk individuals. Thus, bacteriocins are a promising solution to prevent contaminations with L. monocytogenes and other microorganisms during food production and preservation. In the present study, we constructed L. monocytogenes EGD-e/pNZ-Phelp-pHluorin, a strain that constitutively expresses the pH-sensitive fluorescent protein pHluorin, as a sensor strain to detect disruption of the pH gradient by the membrane-damaging activity of bacteriocins. The ratiometric fluorescence properties of pHluorin were validated both in crude extracts and permeabilized cells of this sensor strain. L. monocytogenes EGD-e/pNZ-Phelp-pHluorin was used to assess membrane damaging activity of the bacteriocins nisin A and pediocin PA-1 and to determine the minimal concentrations required for full disruption of the pH gradient across the membrane. Moreover, the sensor strain proved useful to analyze the presence of compounds affecting membrane integrity in supernatants of a nisin Z-producing Lactococcus lactis strain at different timepoints during growth. Supernatants of this strain that were active in disrupting the pH gradient across the membrane were also shown to inhibit growth of L. monocytogenes. In summary, the presented results suggest that the generated sensor strain is a convenient, fast and reliable tool to identify and characterize novel bacteriocins and other compounds that target membrane integrity.publishedVersion© 2018 Crauwels, Schäfer, Weixler, Bar, Diep, Riedel and Seibold. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms

Identification and Characterization of Corynaridin - A novel Linaridin from Corynebacterium Lactis

Genome analysis of Corynebacterium lactis revealed a bacteriocin gene cluster encoding a putative bacteriocin of the linaridin family of ribosomally synthesized and posttranslationally modified peptides (RiPPs). The locus harbors typical linaridin modification enzymes but lacks genes for a decarboxylase and methyltransferase, which is unusual for type B linaridins. Supernatants of Corynebacterium lactis RW3-42 showed antimicrobial activity against Corynebacterium glutamicum. Deletion of the precursor gene crdA clearly linked the antimicrobial activity of the producer strain to the identified gene cluster. Following purification, we observed potent activity of the peptide against Actinobacteria, mainly other members of the genus Corynebacterium, including the pathogenic species Corynebacterium striatum and Corynebacterium amycolatum. Also, low activity against some Firmicutes was observed, but there was no activity against Gram-negative species. The peptide is resilient towards heat but sensitive to proteolytic degradation by trypsin and proteinase K. Analysis by mass spectrometry indicates that corynaridin is processed by cleaving off the leader sequence at a conserved motif and posttranslationally modified by dehydration of all threonine and serin residues, resulting in a monoisotopic mass of 3,961.19 Da. Notably, time-kill kinetics and experiments using live biosensors to monitor membrane integrity suggest bactericidal activity that does not involve formation of pores in the cytoplasmic membrane. As Corynebacterium species are ubiquitous in nature and include important commensals and pathogens of mammalian organisms, secretion of bacteriocins by species of this genus could be a hitherto neglected trait with high relevance for intra- and interspecies competition and infection

Molecular Lymph Node Staging with One-Step Nucleic Acid Amplification and its Prognostic Value for Patients with Colon Cancer: The First Follow-up Study.

Molecular lymph node workup with one-step nucleic acid amplification (OSNA) is a validated diagnostic adjunct in breast cancer and also appealing for colon cancer (CC) staging. This study, for the first time, evaluates the prognostic value of OSNA in CC. The retrospective study includes patients with stage I-III CC from three centres. Lymph nodes were investigated with haematoxylin and eosin (H&amp;E) and with OSNA, applying a 250 copies/μL threshold of CK19 mRNA. Diagnostic value of H&amp;E and OSNA was assessed by survival analysis, sensitivity, specificity and time-dependent receiver operating characteristic curves. Eighty-seven patients were included [mean follow-up 53.4 months (± 24.9)]. Disease recurrence occurred in 16.1% after 19.8 months (± 12.3). Staging with H&amp;E independently predicted worse cancer-specific survival in multivariate analysis (HR = 10.77, 95% CI 1.07-108.7, p = 0.019) but not OSNA (HR = 3.08, 95% CI 0.26-36.07, p = 0.197). With cancer-specific death or recurrence as gold standard, H&amp;E sensitivity was 46.7% (95% CI 21.3-73.4%) and specificity 84.7% (95% CI 74.3-92.1%). OSNA sensitivity and specificity were 60.0% (95% CI 32.3-83.7%) and 75.0% (95% CI 63.4-84.5%), respectively. In patients with CC, OSNA does not add relevant prognostic value to conventional H&amp;E contrasting findings in other cancers. Further studies should assess lower thresholds for OSNA (&lt; 250 copies/μL)