Comparaison de deux méthodes d'estimation du broutage des bactéries par les protozoaires en milieux aquatiques [Courte note]

L'objectif du présent travail est de comparer deux méthodes indépendantes permettant d'estimer, dans les milieux aquatiques, le flux de carbone transitant du compartiment bactérien vers les protozoaires. Les deux méthodes utilisées sont, d'une part, celle basée sur le suivi de la décroissance de radioactivité du matériel génétique bactérien après marquage à la thymidine tritiée (SERVAIS et al., 1985) et, d'autre part, celle de mesure du taux d'ingestion de bactéries fluorescentes (FLB) par les protozoaires. Elles ont été appliquées en parallèle sur des échantillons de la rivière Meuse (Belgique). L'emploi de la première méthode a montré des taux de broutage compris entre 0.002 h-1 et 0.016 h-1 qui représentent en moyenne 72 % des taux de mortalité totale. Une excellente corrélation entre les estimations de flux de broutage obtenues par les deux techniques a été trouvée, mais les valeurs estimées à partir de la méthode FLB sont systématiquement inférieures (d'environ 30% en moyenne) à celles obtenues par l'autre méthode. Une part de cette différence peut vraisemblablement s'expliquer par la non prise en compte par la méthode FLB du broutage par des organismes de taille supérieure à 100 µm.The goal of the present work was to compare two methods allowing to estimate, in aquatic ecosystems, the carbon flux due to grazing of bacteria by protozoa. The first method follows the decrease of labeling in the DNA of natural assemblages of bacteria previously labeled with tritiated thymidine (SERVAIS et al., 1985) and the second procedure is based on the estimation of bacterial ingestion rate by protozoa using fluorescently labeled bacteria (FLB). Both methods were applied in parallel on river Meuse (Belgium) samples. Using the first method, grazing rates in the range 0.002 h-1 to 0.016 h-1 were observed; they represented in average 72 % of the total bacterial mortality rates. A very good correlation between both estimates of the grazing fluxes was found but the data obtained by the FLB method were systematically lower (around 30% in average) than those estimated with the other method. A part of this difference is probably due to he fact that the FLB method does not take into account grazing by organism higher than 100 µm

Canine Ependymoma: Diagnostic Criteria and Common Pitfalls

Reports of canine ependymoma are generally restricted to single case reports with tumor incidence estimated at 2% to 3% of primary central nervous system (CNS) tumors. While most commonly reported in the lateral ventricle, tumors can occur anywhere in the ventricular system and in extraventricular locations. Rosettes and pseudorosettes are a common histologic feature; however, these features can be mimicked by other CNS neoplasms. Thirty-seven potential ependymoma cases were identified in a retrospective database search of 8 institutions, and a histologic review of all cases was conducted. Of 37 cases, 22 candidate cases were further subjected to a consensus histologic and immunohistochemical review, and only 5 of 37 (13.5%) were conclusively identified as ependymoma. The neuroanatomic locations were the lateral ventricle (3/5), third ventricle (1/5), and mesencephalic aqueduct (1/5). Subtypes were papillary (4/5) and tanycytic (1/5). Histologic features included rosettes (5/5), pseudorosettes (5/5), ependymal canals (2/5), tanycytic differentiation (1/5), blepharoplasts (1/5), ciliated cells (1/5), and high nuclear to cytoplasmic ratio (5/5). Immunolabeling for GFAP (4/4) and CKAE1/3 (3/4) was found in pseudorosettes, rosettes, and scattered individual neoplastic cells. Diffuse but variably intense cytoplasmic S100 immunolabeling was detected in 3 of 4 cases. Olig2 intranuclear immunolabeling was observed in less than 1% of the neoplastic cells (3/3). Tumors that had pseudorosettes and mimicked ependymoma included oligodendroglioma, choroid plexus tumor, pituitary corticotroph adenoma, papillary meningioma, and suprasellar germ cell tumor. These findings indicate that canine ependymoma is an extremely rare neoplasm with histomorphologic features that overlap with other primary CNS neoplasms

Improved discrimination of melanotic schwannoma from melanocytic lesions by combined morphological and GNAQ mutational analysis

The histological differential diagnosis between melanotic schwannoma, primary leptomeningeal melanocytic lesions and cellular blue nevus can be challenging. Correct diagnosis of melanotic schwannoma is important to select patients who need clinical evaluation for possible association with Carney complex. Recently, we described the presence of activating codon 209 mutations in the GNAQ gene in primary leptomeningeal melanocytic lesions. Identical codon 209 mutations have been described in blue nevi. The aims of the present study were to (1) perform a histological review of a series of lesions (initially) diagnosed as melanotic schwannoma and analyze them for GNAQ mutations, and (2) test the diagnostic value of GNAQ mutational analysis in the differential diagnosis with leptomeningeal melanocytic lesions. We retrieved 25 cases that were initially diagnosed as melanotic schwannoma. All cases were reviewed using established criteria and analyzed for GNAQ codon 209 mutations. After review, nine cases were classified as melanotic schwannoma. GNAQ mutations were absent in these nine cases. The remaining cases were reclassified as conventional schwannoma (n = 9), melanocytoma (n = 4), blue nevus (n = 1) and lesions that could not be classified with certainty as melanotic schwannoma or melanocytoma (n = 2). GNAQ codon 209 mutations were present in 3/4 melanocytomas and the blue nevus. Including results from our previous study in leptomeningeal melanocytic lesions, GNAQ mutations were highly specific (100%) for leptomeningeal melanocytic lesions compared to melanotic schwannoma (sensitivity 43%). We conclude that a detailed analysis of morphology combined with GNAQ mutational analysis can aid in the differential diagnosis of melanotic schwannoma with leptomeningeal melanocytic lesions

Patient Preferences for Lung Cancer Treatments: A Study Protocol for a Preference Survey Using Discrete Choice Experiment and Swing Weighting

Background: Advanced treatment options for non-small cell lung cancer (NSCLC) consist of immunotherapy, chemotherapy, or a combination of both. Decisions surrounding NSCLC can be considered as preference-sensitive because multiple treatments exist that vary in terms of mode of administration, treatment schedules, and benefit–risk profiles. As part of the IMI PREFER project, we developed a protocol for an online preference survey for NSCLC patients exploring differences in preferences according to patient characteristics (preference heterogeneity). Moreover, this study will evaluate and compare the use of two different preference elicitation methods, the discrete choice experiment (DCE) and the swing weighting (SW) task. Finally, the study explores how demographic (i.e., age, gender, and educational level) and clinical (i.e., cancer stage and line of treatment) information, health literacy, health locus of control, and quality of life may influence or explain patient preferences and the usefulness of a digital interactive tool in providing information on preference elicitation tasks according to patients. Methods: An online survey will be implemented with the aim to recruit 510 NSCLC patients in Belgium and Italy. Participants will be randomized 50:50 to first receive either the DCE or the SW. The survey will also collect information on participants' disease-related status, health locus of control, health literacy, quality of life, and perception of the educational tool. Discussion: This protocol outlines methodological and practical steps to quantitatively elicit and study patient preferences for NSCLC treatment alternatives. Results from this study will increase the understanding of which treatment aspects are most valued by NSCLC patients to inform decision-making in drug development, regulatory approval, and reimbursement. Methodologically, the comparison between the DCE and the SW task will be valuable to gain information on how these preference methods perform against each other in eliciting patient preferences. Overall, this protocol may assist researchers, drug developers, and decision-makers in designing quantitative patient preferences into decision-making along the medical product life cycle

Poor outcome in hypoxic endometrial carcinoma is related to vascular density

Background Identification of endometrial carcinoma (EC) patients at high risk of recurrence is lacking. In this study, the prognostic role of hypoxia and angiogenesis was investigated in EC patients. Methods Tumour slides from EC patients were stained by immunofluorescence for carbonic anhydrase IX (CAIX) as hypoxic marker and CD34 for assessment of microvessel density (MVD). CAIX expression was determined in epithelial tumour cells, with a cut-off of 1%. MVD was assessed according to the Weidner method. Correlations with disease-specific survival (DSS), disease-free survival (DFS) and distant disease-free survival (DDFS) were calculated using Kaplan–Meier curves and Cox regression analysis. Results Sixty-three (16.4%) of 385 ECs showed positive CAIX expression with high vascular density. These ECs had a reduced DSS compared to tumours with either hypoxia or high vascular density (log-rank p = 0.002). Multivariable analysis showed that hypoxic tumours with high vascular density had a reduced DSS (hazard ratio [HR] 3.71, p = 0.002), DDFS (HR 2.68, p = 0.009) and a trend for reduced DFS (HR 1.87, p = 0.054). Conclusions This study has shown that adverse outcome in hypoxic ECs is seen in the presence of high vascular density, suggesting an important role of angiogenesis in the metastatic process of hypoxic EC. Differential adjuvant treatment might be indicated for these patients.publishedVersio

A multicentre, randomized, double-blind, controlled trial of nebulized epinephrine in infants with acute bronchiolitis

Background The treatment of infants with bronchiolitis is largely supportive. The role of bronchodilators is controversial. Most studies of the use of bronchodilators have enrolled small numbers of subjects and have examined only short-term outcomes, such as clinical scores. Methods We conducted a randomized, double-blind, controlled trial comparing nebulized single-isomer epinephrine with placebo in 194 infants admitted to four hospitals in Queens-land, Australia, with a clinical diagnosis of bronchiolitis. Three 4-ml doses of 1 percent nebulized epinephrine or three 4-ml doses of normal saline were administered at four-hour intervals after hospital admission. Observations were made at admission and just before, 30 minutes after, and 60 minutes after each dose. The primary outcome measures were the length of the hospital stay and the time until the infant was ready for discharge. The secondary outcome measures were the degree of change in the respiratory rate, the heart rate, and the respiratory-effort score and the time that supplemental oxygen was required. Results There were no significant overall differences between the groups in the length of the hospital stay (P=0.16) or the time until the infant was ready for discharge (P=0.86). Among infants who required supplemental oxygen and intravenous fluids, the time until the infant was ready for discharge was significantly longer in the epinephrine group than in the placebo group (P=0.02). The need for supplemental oxygen at admission had the greatest influence on the score for severity of illness and strongly predicted the length of the hospital stay and the time until the infant was ready for discharge (

Interfacial Molecular Imprinting in Nanoparticle-Stabilized Emulsions

A new interfacial nano and molecular imprinting approach is developed to prepare spherical molecularly imprinted polymers with well-controlled hierarchical structures. This method is based on Pickering emulsion polymerization using template-modified colloidal particles. The interfacial imprinting is carried out in particle-stabilized oil-in-water emulsions, where the molecular template is presented on the surface of silica nanoparticles during the polymerization of the monomer phase. After polymerization, the template-modified silica nanoparticles are removed from the new spherical particles to leave tiny indentations decorated with molecularly imprinted sites. The imprinted microspheres prepared using the new interfacial nano and molecular imprinting have very interesting features: a well-controlled hierarchical structure composed of large pores decorated with easily accessible molecular binding sites, group selectivity toward a series of chemicals having a common structural moiety (epitopes), and a hydrophilic surface that enables the MIPs to be used under aqueous conditions

Activating mutations of the GNAQ gene: a frequent event in primary melanocytic neoplasms of the central nervous system

Primary melanocytic neoplasms of the central nervous system (CNS) are uncommon neoplasms derived from melanocytes that normally can be found in the leptomeninges. They cover a spectrum of malignancy grades ranging from low-grade melanocytomas to lesions of intermediate malignancy and overtly malignant melanomas. Characteristic genetic alterations in this group of neoplasms have not yet been identified. Using direct sequencing, we investigated 19 primary melanocytic lesions of the CNS (12 melanocytomas, 3 intermediate-grade melanocytomas, and 4 melanomas) for hotspot oncogenic mutations commonly found in melanocytic tumors of the skin (BRAF, NRAS, and HRAS genes) and uvea (GNAQ gene). Somatic mutations in the GNAQ gene at codon 209, resulting in constitutive activation of GNAQ, were detected in 7/19 (37%) tumors, including 6/12 melanocytomas, 0/3 intermediate-grade melanocytomas, and 1/4 melanomas. These GNAQ-mutated tumors were predominantly located around the spinal cord (6/7). One melanoma carried a BRAF point mutation that is frequently found in cutaneous melanomas (c.1799 T>A, p.V600E), raising the question whether this is a metastatic rather than a primary tumor. No HRAS or NRAS mutations were detected. We conclude that somatic mutations in the GNAQ gene at codon 209 are a frequent event in primary melanocytic neoplasms of the CNS. This finding provides new insight in the pathogenesis of these lesions and suggests that GNAQ-dependent mitogen-activated kinase signaling is a promising therapeutic target in these tumors. The prognostic and predictive value of GNAQ mutations in primary melanocytic lesions of the CNS needs to be determined in future studies