868 research outputs found
On the robust measurement of inflectional diversity
Lexical diversity measures are notoriously sensitive to variations of sample size and recent approaches to this issue typically involve the computation of the average variety of lexical units in random subsamples of fixed size. This methodology has been further extended to measures of inflectional diversity such as the average number of wordforms per lexeme, also known as the mean size of paradigm (MSP) index.
In this contribution we argue that, while random sampling can indeed be used to increase the robustness of inflectional diversity measures, using a fixed subsample size is only justified under the hypothesis that the corpora that we compare have the same degree of lexematic diversity. In the more general case where they may have differing degrees of lexematic diversity, a more sophisticated strategy can and should be adopted.
A novel approach to the measurement of inflectional diversity is proposed, aiming to cope not only with variations of sample size, but also with variations of lexematic diversity. The robustness of this new method is empirically assessed and the results show that while there is still room for improvement, the proposed methodology considerably attenuates the impact of lexematic diversity discrepancies on the measurement of inflectional diversity
Multimodal imaging of retinal pigment epithelial detachments in patients with C3 glomerulopathy: case report and review of the literature.
To describe the optical coherence tomography angiograhy (OCTA) of drusenoid pigment epithelial detachments (PEDs) in a woman affected by Complement 3 (C3) glomerulopathy, which represents a spectrum of glomerular diseases characterized on fluorescent microscopy by C3 accumulation with absent, or scanty, immunoglobulin deposits. It is due to acquired or genetically defective alternative pathway control and is generally associated with drusen-like deposits in Bruch's membrane, as well as choriocapillaris. These retinal lesions can be associated with choroidal neovascularization and central serous chorioretinopathy (CSCR). OCTA is useful to detect neovascularization without injecting a contrast product, particularly in these patients who may have renal insufficiency.
A 28-year-old woman affected by C3 glomerulpathy was diagnosed with asymptomatic multiple bilateral PEDs during a routine ophthalmologic consultation. To better characterize the lesions, multimodal imaging was performed and included: optic coherence tomography (OCT), en-face OCT, OCTA, fluorescence and indocyanine angiography. The OCTA clearly identified vascular network rarefaction with decreased choriocapillary vascularization. It confirmed that PEDs associated with C3 glomerulonephritis are not vascularized, but rather of serous type.
Patients affected by C3 glomerulopathy can develop neovascular membranes as retinal complications of pigment epithelial detachments. Optical coherence angiography may be indicated to identify this complication, without injecting any contrast product that could produce further kidney damage
CTCF loss has limited effects on global genome architecture in Drosophila despite critical regulatory functions.
Vertebrate genomes are partitioned into contact domains defined by enhanced internal contact frequency and formed by two principal mechanisms: compartmentalization of transcriptionally active and inactive domains, and stalling of chromosomal loop-extruding cohesin by CTCF bound at domain boundaries. While Drosophila has widespread contact domains and CTCF, it is currently unclear whether CTCF-dependent domains exist in flies. We genetically ablate CTCF in Drosophila and examine impacts on genome folding and transcriptional regulation in the central nervous system. We find that CTCF is required to form a small fraction of all domain boundaries, while critically controlling expression patterns of certain genes and supporting nervous system function. We also find that CTCF recruits the pervasive boundary-associated factor Cp190 to CTCF-occupied boundaries and co-regulates a subset of genes near boundaries together with Cp190. These results highlight a profound difference in CTCF-requirement for genome folding in flies and vertebrates, in which a large fraction of boundaries are CTCF-dependent and suggest that CTCF has played mutable roles in genome architecture and direct gene expression control during metazoan evolution
CAPNOCYTOPHAGA CANIMORSUS ENDOPHTHALMITIS AFTER CATARACT SURGERY LINKED TO SALIVARY DOG-TO-HUMAN TRANSMISSION.
To describe a case of acute postoperative bacterial endophthalmitis because of Capnocytophaga canimorsus after cataract surgery, with probable contamination through salivary droplets of dog two days after the procedure.
An 83-year-old woman who underwent uncomplicated cataract extraction with intraocular lens implantation, presented 12 days later with acute pain, redness, and vision loss in her left eye. Visual acuity was hand motion and clinical findings suggested the diagnosis of acute postoperative endophthalmitis. The patient underwent diagnostic vitrectomy, intravitreal ceftazidime/vancomycin injection and received oral moxifloxacin (400 mg/day). Two days later, she underwent complete pars-plana vitrectomy because of the absence of clinical improvement. Vitreous samples showed gram-negative bacterium on direct examination but cultures remained sterile, which prompted the realization of a broad-range bacterial polymerase chain reaction analysis.
Polymerase chain reaction on the vitreous sample detected C. canimorsus, a fastidious gram-negative bacterium of the oral canine flora. When asked for recent contact with dogs, the patient reported having proceeded to an intensive tooth care session for her dog at postoperative Day 2. Intravenous ceftriaxone (2 g/day) was added to the treatment. Anterior and posterior segment inflammation slowly resolved, and final visual acuity was 20/160.
Although very rare, this complication suggests that patients undergoing ocular surgery should avoid contact with salivary secretions of pets during the early postoperative period. Diagnostic broad-range bacterial polymerase chain reaction is useful to detect unconventional or slow-growing agents in vitreous samples
TIE-2-expressing monocytes are lymphangiogenic and associate specifically with lymphatics of human breast cancer.
In experimental mouse models of cancer, increasingly compelling evidence point toward a contribution of tumor associated macrophages (TAM) to tumor lymphangiogenesis. Corresponding experimental observations in human cancer remain scarce although lymphatic metastasis is widely recognized as a predominant route for tumor spread. We previously showed that, in malignant tumors of untreated breast cancer (BC) patients, TIE-2-expressing monocytes (TEM) are highly proangiogenic immunosuppressive cells and that TIE-2 and VEGFR signaling pathways drive TEM immunosuppressive function. We report here that, in human BC, TEM express the canonical lymphatic markers LYVE-1, Podoplanin, VEGFR-3 and PROX-1. Critically, both TEM acquisition of lymphatic markers and insertion into lymphatic vessels were observed in tumors but not in adjacent non-neoplastic tissues, suggesting that the tumor microenvironment shapes both TEM phenotype and spatial distribution. We assessed the lymphangiogenic activity of TEM isolated from dissociated primary breast tumors in vitro and in vivo using endothelial cells (EC) sprouting assay and corneal vascularization assay, respectively. We show that, in addition to their known hemangiogenic function, TEM isolated from breast tumor display a lymphangiogenic activity. Importantly, TIE-2 and VEGFR pathways display variable contributions to TEM angiogenic and lymphangiogenic activities across BC patients; however, combination of TIE-2 and VEGFR kinase inhibitors abrogated these activities and overcame inter-patient variability. These results highlight the direct contribution of tumor TEM to the breast tumor lymphatic network and suggest a combined use of TIE-2 and VEGFR kinase inhibitors as a therapeutic approach to block hem- and lymphangiogenesis in BC
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Protocol for a feasibility randomized controlled trial to evaluate the efficacy, safety and tolerability of N-acetylcysteine in reducing adverse drug reactions among adults treated for multidrug-resistant tuberculosis in Tanzania
Funding: This study receives financial supports from the European and Developed Countries Clinical Trials Partnership (EDCTP2) program supported by the European Union project through the Senior Fellowship Scheme TMA1463 awarded to Stellah G Mpagama.Background Adverse drug reactions (ADRs) frequently occur in patients using second-line anti-tuberculosis medicine for treatment of multidrug resistant tuberculosis (MDR-TB). ADRs contribute to treatment interruptions which can compromise treatment response and risk acquired drug resistance to critical newer drugs such as bedaquiline, while severe ADRs carry considerable morbidity and mortality. N-acetylcysteine (NAC) has shown promise in reducing ADRs for medications related to TB in case series or randomized controlled trials in other medical conditions, yet evidence is lacking in MDR-TB patients. TB endemic settings have limited capacity to conduct clinical trials. We designed a proof-of-concept clinical trial primarily to explore the preliminary evidence on the protective effect of NAC among people treated for MDR-TB with second-line anti-TB medications. Methods This is a proof-of-concept randomized open label clinical trial with 3 treatment arms including a control arm, an interventional arm of NAC 900 mg daily, and an interventional arm of NAC 900 mg twice-daily administered during the intensive phase of MDR-TB treatment. Patients initiating MDR-TB treatment will be enrolled at Kibong’oto National Center of Excellence for MDR-TB in the Kilimanjaro region of Tanzania. The minimum anticipated sample size is 66; with 22 participants in each arm. ADR monitoring will be performed at baseline and daily follow-up over 24 weeks including blood and urine specimen collection for hepatic and renal function and electrolyte abnormalities, and electrocardiogram. Sputum will be collected at baseline and monthly thereafter and cultured for mycobacteria as well as assayed for other molecular targets of Mycobacterium tuberculosis. Adverse drug events will be analysed over time using mixed effect models. Mean differences between arms in change of the ADRs from baseline (with 95% confidence intervals) will be derived from the fitted model. Discussion Given that NAC promotes synthesis of glutathione, an intracellular antioxidant that combats the impact of oxidative stress, it may protect against medication induced oxidative damage in organs such as liver, pancreas, kidney, and cells of the immune system. This randomized controlled trial will determine if NAC leads to fewer ADRs, and if this protection is dose dependent. Fewer ADRs among patients treated with MDR-TB may significantly improve treatment outcomes for multidrug regimens that necessitate prolonged treatment durations. Conduct of this trial will set the needed infrastructure for clinical trials.Publisher PDFPeer reviewe
Hyaline fibromatosis syndrome inducing mutations in the ectodomain of anthrax toxin receptor 2 can be rescued by proteasome inhibitors.
Hyaline Fibromatosis Syndrome (HFS) is a human genetic disease caused by mutations in the anthrax toxin receptor 2 (or cmg2) gene, which encodes a membrane protein thought to be involved in the homeostasis of the extracellular matrix. Little is known about the structure and function of the protein or the genotype-phenotype relationship of the disease. Through the analysis of four patients, we identify three novel mutants and determine their effects at the cellular level. Altogether, we show that missense mutations that map to the extracellular von Willebrand domain or the here characterized Ig-like domain of CMG2 lead to folding defects and thereby to retention of the mutated protein in the endoplasmic reticulum (ER). Mutations in the Ig-like domain prevent proper disulphide bond formation and are more efficiently targeted to ER-associated degradation. Finally, we show that mutant CMG2 can be rescued in fibroblasts of some patients by treatment with proteasome inhibitors and that CMG2 is then properly transported to the plasma membrane and signalling competent, identifying the ER folding and degradation pathway components as promising drug targets for HFS
Electrospun aniline-tetramer-co-polycaprolactone fibers for conductive, biodegradable scaffolds
Conjugated polymers have been proposed as promising materials for scaffolds in tissue engineering applications. However, the restricted processability and biodegradability of conjugated polymers limit their use for biomedical applications. Here we synthesized a block-co-polymer of aniline tetramer and PCL (AT-PCL), and processed it into fibrous non-woven scaffolds by electrospinning. We showed that fibronectin (Fn) adhesion was dependent on the AT-PCL oxidative state, with a reduced Fn unfolding length on doped membranes. Furthermore, we demonstrated the cytocompatibility and potential of these membranes to support the growth and osteogenic differentiation of MC3T3-E1 cells over 21 days
Phosphoenolpyruvate carboxylase dentified as a key enzyme in erythrocytic Plasmodium falciparum carbon metabolism
Phospoenolpyruvate carboxylase (PEPC) is absent from humans but encoded in thePlasmodium falciparum genome, suggesting that PEPC has a parasite-specific function. To investigate its importance in P. falciparum, we generated a pepc null mutant (D10Δpepc), which was only achievable when malate, a reduction product of oxaloacetate, was added to the growth medium. D10Δpepc had a severe growth defect in vitro, which was partially reversed by addition of malate or fumarate, suggesting that pepc may be essential in vivo. Targeted metabolomics using 13C-U-D-glucose and 13C-bicarbonate showed that the conversion of glycolytically-derived PEP into malate, fumarate, aspartate and citrate was abolished in D10Δpepc and that pentose phosphate pathway metabolites and glycerol 3-phosphate were present at increased levels. In contrast, metabolism of the carbon skeleton of 13C,15N-U-glutamine was similar in both parasite lines, although the flux was lower in D10Δpepc; it also confirmed the operation of a complete forward TCA cycle in the wild type parasite. Overall, these data confirm the CO2 fixing activity of PEPC and suggest that it provides metabolites essential for TCA cycle anaplerosis and the maintenance of cytosolic and mitochondrial redox balance. Moreover, these findings imply that PEPC may be an exploitable target for future drug discovery
Inhibition of G-protein signalling in cardiac dysfunction of intellectual developmental disorder with cardiac arrhythmia (IDDCA) syndrome
BACKGROUND: Pathogenic variants of GNB5 encoding the β5 subunit of the guanine nucleotide-binding protein cause IDDCA syndrome, an autosomal recessive neurodevelopmental disorder associated with cognitive disability and cardiac arrhythmia, particularly severe bradycardia. METHODS: We used echocardiography and telemetric ECG recordings to investigate consequences of Gnb5 loss in mouse. RESULTS: We delineated a key role of Gnb5 in heart sinus conduction and showed that Gnb5-inhibitory signalling is essential for parasympathetic control of heart rate (HR) and maintenance of the sympathovagal balance. Gnb5-/- mice were smaller and had a smaller heart than Gnb5+/+ and Gnb5+/- , but exhibited better cardiac function. Lower autonomic nervous system modulation through diminished parasympathetic control and greater sympathetic regulation resulted in a higher baseline HR in Gnb5-/- mice. In contrast, Gnb5-/- mice exhibited profound bradycardia on treatment with carbachol, while sympathetic modulation of the cardiac stimulation was not altered. Concordantly, transcriptome study pinpointed altered expression of genes involved in cardiac muscle contractility in atria and ventricles of knocked-out mice. Homozygous Gnb5 loss resulted in significantly higher frequencies of sinus arrhythmias. Moreover, we described 13 affected individuals, increasing the IDDCA cohort to 44 patients. CONCLUSIONS: Our data demonstrate that loss of negative regulation of the inhibitory G-protein signalling causes HR perturbations in Gnb5-/- mice, an effect mainly driven by impaired parasympathetic activity. We anticipate that unravelling the mechanism of Gnb5 signalling in the autonomic control of the heart will pave the way for future drug screening
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