59 research outputs found
Diverse Stress-Inducing Treatments cause Distinct Aberrant Body Morphologies in the Chlamydia-Related Bacterium, Waddlia chondrophila.
Chlamydiae, such as Chlamydia trachomatis and Chlamydia pneumoniae, can cause chronic infections. It is believed that persistent forms called aberrant bodies (ABs) might be involved in this process. AB formation seems to be a common trait of all members of the Chlamydiales order and is caused by distinct stress stimuli, such as β-lactam antibiotics or nutrient starvation. While the diverse stimuli inducing ABs are well described, no comprehensive morphological characterization has been performed in Chlamydiales up to now. We thus infected mammalian cells with the Chlamydia-related bacterium Waddlia chondrophila and induced AB formation using different stimuli. Their morphology, differences in DNA content and in gene expression were assessed by immunofluorescence, quantitative PCR, and reverse transcription PCR, respectively. All stimuli induced AB formation. Interestingly, we show here for the first time that the DNA gyrase inhibitor novobiocin also caused appearance of ABs. Two distinct patterns of ABs could be defined, according to their morphology and number: (i) small and multiple ABs versus (ii) large and rare ABs. DNA replication of W. chondrophila was generally not affected by the different treatments. Finally, no correlation could be observed between specific types of ABs and expression patterns of mreB and rodZ genes
Advantages of robotic right colectomy over laparoscopic right colectomy beyond the learning curve: a systematic review and meta-analysis
Background: With the widespread application of robotic systems and the increasing number of studies comparing robotic right colectomy (RRC) and laparoscopic right colectomy (LRC), there is a need for an up-to-date systemic review and meta-analysis assessing the advantages of this technique. Methods: The systemic review was performed in Medline, Scopus, Embase, Cochrane Oral Health Group Specialized Register and Google Scholar databases searching for studies comparing RRC and LRC, with no date restriction but limited to English and French literature. Two independent reviewers performed data extraction and qualitative synthesis. Random-effects models were used to summarize the risk ratio (RR) and mean differences (MD) with 95% confidence interval (CI). Results: Twenty-six non-randomized clinical trials (NRCTs) and 1 RCT were included. Overall, 2,314 patients underwent RRC and 17,791 LRC. Operative time was significantly longer for RRC with a MD of 45.36 min (95% CI: 31.75-58.97; P<0.00001). Conversion rate was significantly lower in the RRC group with a RR of 0.47 (95% CI: 0.27-0.81; P=0.007, I-2=33%). Also, the number of harvested lymph node was significantly higher in the RRC group than the LRC group, with a MD of 2.03 (95% CI: 0.45-3.61; P=0.01, I-2=68%). Estimated blood loss favored RRC, with a MD of-8.68 (95% CI:-17.27 to-0.08; P=0.05, I-2=46%). There was no difference in the overall complication rate, mortality, anastomotic leakage, and time to first flatus. However, a significantly shorter hospital stay was associated with RRC, with a MD of -0.60 (95% CI:-1.01 to-0.19; P=0.004, I-2=64%). No quantitative analysis could be performed for oncological outcomes. RRC was associated with significantly higher costs (MD 3,185.50 USD; 95% CI: 720.98-5650.02; P=0.01, I-2=94%). Conclusions: RRC is a safe procedure that may offer certain advantages over LRC as lower conversion rate, blood loss, hospital stay. However, this should be balanced out with increased operative time and higher costs
A predation assay using amoebae to screen for virulence factors unearthed the first W. chondrophila inclusion membrane protein.
Waddlia chondrophila is an intracellular bacterium phylogenetically related to the well-studied human and animal pathogens of the Chlamydiaceae family. In the last decade, W. chondrophila was convincingly demonstrated to be associated with adverse pregnancy outcomes in humans and abortions in animals. All members of the phylum Chlamydiae possess a Type Three Secretion System that they use for delivering virulence proteins into the host cell cytosol to modulate their environment and create optimal conditions to complete their life cycle. To identify W. chondrophila virulence proteins, we used an original screening approach that combines a cosmid library with an assay monitoring resistance to predation by phagocytic amoebae. This technique combined with bioinformatic data allowed the identification of 28 candidate virulence proteins, including Wimp1, the first identified inclusion membrane protein of W. chondrophila
PDE-5i Management of Erectile Dysfunction After Rectal Surgery: A Systematic Review Focusing on Treatment Efficacy
Erectile dysfunction (ED) is one of the main functional complications of surgical resections of the rectum due to rectal cancers or inflammatory bowel disease (IBD). The present systematic review aimed at revising ED management strategies applied after rectal resections and their efficacy in terms of improvement of the International Index of Erectile Function (IIEF) score. A literature search was conducted on Medline, EMBASE, Scopus, and Cochrane databases by two independent reviewers following the PRISMA guidelines. Randomized and nonrandomized controlled trials (RCTs, NRCTs), case-control studies, and case series evaluating medical or surgical therapies for ED diagnosed after rectal surgery for both benign and malignant pathologies were eligible for inclusion. Out of 1028 articles initially identified, only five met the inclusion criteria: two RCTs comparing oral phosphodiesterase type-5 inhibitor (PDE-5i) versus placebo; one NRCT comparing PDE-5i versus PDE-5i + vacuum erection devices (VEDs) versus control; and two before-after studies on PDE-5i. A total of 253 (82.7%) rectal cancer patients and 53 (17.3%) IBD patients were included. Based on two RCTs, PDE-5i significantly improved IIEF compared to placebo at 3 months (SMD = 1.07; 95% CI [0.65, 1.48]; p <.00001; I2 = 39%). Improved IIEF was also reported with PDE-5i + VED at 12 months. There is a paucity of articles in the literature that specifically assess efficacy of ED treatments after rectal surgery. Many alternative treatment strategies to PDE-5is remain to be investigated. Future studies should implement standardized preoperative, postoperative, and follow-up sexual function assessment in patients undergoing rectal resections
Conversions related to adhesions in abdominal surgery. Robotic versus laparoscopic approach: a multicentre experience
Background: An advantage of robotic surgery over laparoscopy is the lower rate of unplanned conversion. One of the implicated reasons for conversion is adhesions from previous abdominal surgeries (PASs). Methods: A comparative analysis of 98 patients with history of open PAS treated by laparoscopic or robotic surgery was performed. Primary endpoint was the rate of conversion to open surgery related to adhesiolysis. Secondary endpoints were short-term outcomes and complications. Results: Conversion rate specifically related to adhesiolysis was significantly lower in robotic group (13 for laparoscopic group vs. 2 for robotic group; p = 0.046). Conversions occurred during adhesiolysis were significantly related to severity of adhesions expressed by peritoneal adhesion index (PAI) score (p < 0.001), number of abdominal areas involved by adhesions (p < 0.001) and severity of PAI into the target area of surgical intervention (p = 0.021). Conclusions: Benefits of robotic surgery are more noticeable in performing procedures with increasing technical difficulties
Multi-descriptor random sampling for patch-based face recognition
While there has been a massive increase in research into face recognition, it remains a challenging problem due to conditions present in real life. This paper focuses on the inherently present issue of partial occlusion distortions in real face recognition applications. We propose an approach to tackle this problem. First, face images are divided into multiple patches before local descriptors of Local Binary Patterns and Histograms of Oriented Gradients are applied on each patch. Next, the resulting histograms are concatenated, and their dimensionality is then reduced using Kernel Principle Component Analysis. Once completed, patches are randomly selected using the concept of random sampling to finally construct several sub-Support Vector Machine classifiers. The results obtained from these sub-classifiers are combined to generate the final recognition outcome. Experimental results based on the AR face database and the Extended Yale B database show the effectiveness of our proposed technique
Predictors of mortality following emergency open colectomy for ischemic colitis: A single-center experience
Background: Ischemic colitis (IC) is a severe emergency in gastrointestinal surgery. The aim of the present study was to identify the predictors of postoperative mortality after emergent open colectomy for IC treatment. Additionally, we compared postoperative outcomes of patients undergoing emergent colectomy due to aortic surgery-related IC (AS-IC group) vs. other IC etiologies (Other-IC group). Methods: We analyzed records of consecutive patients who underwent emergency open colectomy for IC between 2008 and 2019. Logistic regression analysis was performed to identify clinical and operative parameters associated with postoperative mortality. The AS-IC and Other-IC groups were compared for mortality, morbidity, ICU stay, hospital stay, and survival. Results: During the study period, 94 patients (mean age, 67.4 ± 13.7 years) underwent emergent open colectomy for IC. In the majority of cases, IC involved the entire colon (53.2%) and vasopressor agents were required preoperatively (63.8%) and/or intraoperatively (78.8%). Thirty-four patients underwent surgery due to AS-IC, whereas 60 due to Other-IC causes. In the AS-IC group, 9 patients had undergone endovascular aortic repair and 25 open aortic surgery; 61.8% of patients needed aortic surgery for ruptured abdominal aortic aneurism (AAA). Overall, 66 patients (70.2%) died within 90 days from surgery. The AS-IC and Other-IC groups showed similar operative outcomes and postoperative complication rates. However, the duration of the ICU stay (19 days vs. 11 days; p = 0.003) and of the total hospital stay (22 days vs. 16 days; p = 0.016) was significantly longer for the AS-IC group than for the Other-IC group. The rate of intestinal continuity restoration at 1 year after surgery was higher for the Other-IC group than for the AS-IC group (58.8% vs. 22.2%; p = 0.05). In the multivariate model, preoperative increased lactate levels, a delay between signs/symptoms' onset and surgery > 12 h, and the occurrence of postoperative acute kidney injury were statistically associated with postoperative mortality. Neither IC etiology (aortic surgery vs. other etiology) nor ruptured AAA was associated with postoperative mortality. Conclusion: Emergency open colectomy for IC is associated with high postoperative mortality, which appears to be unrelated to the IC etiology. Preoperative lactate levels, > 12-h delay to surgery, and postoperative acute kidney injury are independent predictors of postoperative mortality
Sequencing the Obligate Intracellular Rhabdochlamydia helvetica within Its Tick Host Ixodes ricinus to Investigate Their Symbiotic Relationship.
The Rhabdochlamydiaceae family is one of the most widely distributed within the phylum Chlamydiae, but most of its members remain uncultivable. Rhabdochlamydia 16S rRNA was recently reported in more than 2% of 8,534 pools of ticks from Switzerland. Shotgun metagenomics was performed on a pool of five female Ixodes ricinus ticks presenting a high concentration of chlamydial DNA, allowing the assembly of a high-quality draft genome. About 60% of sequence reads originated from a single bacterial population that was named "Candidatus Rhabdochlamydia helvetica" whereas only few thousand reads mapped to the genome of "Candidatus Midichloria mitochondrii," a symbiont normally observed in all I. ricinus females. The 1.8 Mbp genome of R. helvetica is smaller than other Chlamydia-related bacteria. Comparative analyses with other chlamydial genomes identified transposases of the PD-(D/E)XK nuclease family that are unique to this new genome. These transposases show evidence of interphylum horizontal gene transfers between multiple arthropod endosymbionts, including Cardinium spp. (Bacteroidetes) and diverse proteobacteria such as Wolbachia, Rickettsia spp. (Rickettsiales), and Caedimonas varicaedens (Holosporales). Bacterial symbionts were previously suggested to provide B-vitamins to hematophagous hosts. However, incomplete metabolic capacities including for B-vitamin biosynthesis, high bacterial density and limited prevalence suggest that R. helvetica is parasitic rather than symbiotic to its host. The identification of novel Rhabdochlamydia strains in different hosts and their sequencing will help understanding if members of this genus have become highly specialized parasites with reduced genomes, like the Chlamydiaceae, or if they could be pathogenic to humans using ticks as a transmission vector
Molecular biology of histidine decarboxylase and prostaglandin receptors
Histamine and prostaglandins (PGs) play a variety of physiological roles as autacoids, which function in the vicinity of their sources and maintain local homeostasis in the body. They stimulate target cells by acting on their specific receptors, which are coupled to trimeric G proteins. For the precise understanding of the physiological roles of histamine and PGs, it is necessary to clarify the molecular mechanisms involved in their synthesis as well as their receptor-mediated responses. We cloned the cDNAs for mouse l-histidine decarboxylase (HDC) and 6 mouse prostanoid receptors (4 PGE2 receptors, PGF receptor, and PGI receptor). We then characterized the expression patterns and functions of these genes. Furthermore, we established gene-targeted mouse strains for HDC and PG receptors to explore the novel pathophysiological roles of histamine and PGs. We have here summarized our research, which should contribute to progress in the molecular biology of HDC and PG receptors
Regulatory (pan-)genome of an obligate intracellular pathogen in the PVC superphylum.
Like other obligate intracellular bacteria, the Chlamydiae feature a compact regulatory genome that remains uncharted owing to poor genetic tractability. Exploiting the reduced number of transcription factors (TFs) encoded in the chlamydial (pan-)genome as a model for TF control supporting the intracellular lifestyle, we determined the conserved landscape of TF specificities by ChIP-Seq (chromatin immunoprecipitation-sequencing) in the chlamydial pathogen Waddlia chondrophila. Among 10 conserved TFs, Euo emerged as a master TF targeting >100 promoters through conserved residues in a DNA excisionase-like winged helix-turn-helix-like (wHTH) fold. Minimal target (Euo) boxes were found in conserved developmentally-regulated genes governing vertical genome transmission (cytokinesis and DNA replication) and genome plasticity (transposases). Our ChIP-Seq analysis with intracellular bacteria not only reveals that global TF regulation is maintained in the reduced regulatory genomes of Chlamydiae, but also predicts that master TFs interpret genomic information in the obligate intracellular α-proteobacteria, including the rickettsiae, from which modern day mitochondria evolved
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