186 research outputs found
Elaboration of a biotic index of pollution using macroinvertebrates for the monitoring of Lake Nokoué in Benin
A study on the relationships between the physicochemical parameters and of the macroinvertebrates of the Lake Nokoué was carried out for the purpose of developing a biotic index of pollution. A total of 96 stations were prospected twice during the flooding and the dry seasons from September 2004 to February 2006. At each station, seven physicochemical parameters were measured and macroinvertebrates were collected. Canonical analyses of correspondence were used to show the relations between the parameters of the environment and the macroinvertebrates. A self-organizing map (SOM) of Kohonen allows the categorization of the studied stations into four groups according to different degrees of pollution. Rough scores were allotted to each taxon according to its abundance in the various groups of stations determined by the SOM for each campaign. A synthesis of the data obtained from the four field surveys allows the assignment of a score to each taxon according to its abundance in the different groups of stations. A biotic index was developed and used for the evaluation of the level of pollution of the stations studied. It then emerged that the borders of the lake present a «poor quality» of water; however, during the dry season there is slight improvement.© 2015 International Formulae Group. All rights reserved.Keywords: Biotic index, pollution, invertebrates, lagoons, Benin, West Afric
Expression of HLA-G in human cornea, an immune-privileged tissue.
Human leukocyte antigen (HLA)-G retains the capacity to modulate immune responses, favoring the establishment of tolerance in solid-tissue allotransplants. To better understand the mechanisms that promote corneal allograft survival, we investigated whether HLA-G was an immunoregulatory factor involved in corneal immunology. We therefore sought HLA-G expression in corneal tissues. Corneal transplantation consists in replacing the center of a diseased cornea with normal corneal tissue. Two corneal parts are not used in such surgery: diseased central corneal tissue and peripheral normal cornea. For this study, we used healthy corneas obtained from deceased donors and diseased corneas obtained from patients with pseudophakic bullous keratopathy or keratoconus who had undergone corneal transplantation. Immunohistochemical analysis carried out on the cryopreserved corneas showed a positive immunohistochemical staining with anti-HLA-G, anti-HLA-A, -B, and -C, and anti-HLA class I monoclonal antibodies. Staining was obtained for keratocytes, epithelial cells, and endothelial cells from both healthy and pathologic human corneas, revealing the presence of HLA class I proteins, including HLA-G. HLA-G transcripts were detected in normal cornea by reverse transcriptase-polymerase chain reaction with a classical pattern of alternative splicing. The detection of HLA-G protein in adult corneas leads to the conclusion that this protein may contribute to the maintenance of the privileged immune status of cornea
HLA-G*0105N null allele encodes functional HLA-G isoforms.
Expression of the nonclassical HLA class I antigen, HLA-G, is associated with immune tolerance in view of its role in maintaining the fetus in utero, allowing tumor escape, and favoring graft acceptance. Expressed on invasive trophoblast cells, HLA-G molecules bind inhibitory receptors on maternal T lymphocytes and NK cells, thereby blocking their cytolytic activities and protecting the fetus from maternal immune system attack. The HLA-G gene consists of 15 alleles, including a null allele, HLA-G*0105N. HLA-G*0105N presents a single base deletion, preventing translation of both membrane-bound (HLA-G1) and full-length soluble isoforms (HLA-G5) as well as of the spliced HLA-G4 isoform. The identification of healthy subjects homozygous for this HLA-G null allele suggests that the HLA-G*0105N allele may generate other HLA-G isoforms, such as membrane-bound HLA-G2 and -G3 and the soluble HLA-G6 and -G7 proteins, which may substitute for HLA-G1 and -G5, thus assuming the immune tolerogeneic function of HLA-G. To investigate this point, we cloned genomic HLA-G*0105N DNA and transfected it into an HLA-class I-positive human cell line. The results obtained indicated that HLA-G proteins were indeed present in HLA-G*0105N-transfected cells and were able to protect against NK cell lysis. These findings emphasize the role of the other HLA-G isoforms as immune tolerogeneic molecules that may also contribute to maternal tolerance of the semiallogenic fetus as well as tumor escape and other types of allogeneic tissue acceptance
The epidemiology of acne vulgaris in a multiethnic adolescent population from Rotterdam, the Netherlands:A cross-sectional study
Background: Although acne is a prevalent multifactorial inflammatory skin condition, few studies were performed in multiethnic populations. Objectives: To study the prevalence and determinants of acne in a multiethnic study at the start of puberty. Methods: This cross-sectional study is embedded in Generation R, a population-based prospective study from Rotterdam, the Netherlands. Three-dimensional facial photos at the center visit in 2016-2019 (of ∼13-year-olds) were used to grade acne severity using the Global Evaluation of the Acne Severity (GEA). Analyses were stratified by biological sex and explored through chi-square tests and multivariable ordinal logistic regression. Results: A total of 4561 children (51% girls) with a median age of 13.5 (IQR 13.3-13.6) were included. The visible acne prevalence (GEA 2-5) for girls vs boys was 62% vs 45% and moderate-to-severe acne (GEA 3-5) 14% vs 9%. Higher puberty stages (adjusted odds ratios: 1.38 [1.20-1.59] and 2.16 [1.86-2.51] for girls and boys, respectively) and darker skin colors V and VI (adjusted odds ratios: 1.90 [1.17-3.08] and 2.43 [1.67-3.56]) were associated with more severe acne in both sexes, and being overweight in boys (adjusted odds ratio: 1.58 [1.15-2.17]). Limitations: Cross-sectional design. Conclusions: Acne prevalence was high at the age of 13 years and was associated with advanced puberty, darker skin color, and weight status.</p
The epidemiology of acne vulgaris in a multiethnic adolescent population from Rotterdam, the Netherlands:A cross-sectional study
Background: Although acne is a prevalent multifactorial inflammatory skin condition, few studies were performed in multiethnic populations. Objectives: To study the prevalence and determinants of acne in a multiethnic study at the start of puberty. Methods: This cross-sectional study is embedded in Generation R, a population-based prospective study from Rotterdam, the Netherlands. Three-dimensional facial photos at the center visit in 2016-2019 (of ∼13-year-olds) were used to grade acne severity using the Global Evaluation of the Acne Severity (GEA). Analyses were stratified by biological sex and explored through chi-square tests and multivariable ordinal logistic regression. Results: A total of 4561 children (51% girls) with a median age of 13.5 (IQR 13.3-13.6) were included. The visible acne prevalence (GEA 2-5) for girls vs boys was 62% vs 45% and moderate-to-severe acne (GEA 3-5) 14% vs 9%. Higher puberty stages (adjusted odds ratios: 1.38 [1.20-1.59] and 2.16 [1.86-2.51] for girls and boys, respectively) and darker skin colors V and VI (adjusted odds ratios: 1.90 [1.17-3.08] and 2.43 [1.67-3.56]) were associated with more severe acne in both sexes, and being overweight in boys (adjusted odds ratio: 1.58 [1.15-2.17]). Limitations: Cross-sectional design. Conclusions: Acne prevalence was high at the age of 13 years and was associated with advanced puberty, darker skin color, and weight status.</p
A baseline assessment of emerging organic contaminants in New Zealand groundwater
Emerging organic contaminants (EOCs) are manufactured compounds, used for a range of purposes, that are a rising concern for freshwater quality, human and aquatic health. Their occurrence in groundwater has been demonstrated in several international surveys. We conducted the first baseline survey on EOC occurrence in New Zealand groundwater, using a wide-screening approach (723 compounds) and a novel stratified to mean residence time (MRT) randomised design to inform future monitoring. A total of 61 sites were sampled: 51 baseline sites from the State of the Environment (SOE) network in the Waikato region and 10 targeted sites located in the vicinity of known EOC sources for comparison. EOCs were detected at 91% of the baseline sites at concentrations ranging from 0.1 to 11,000 ng·L−1. Multiple groups of EOCs were encountered: pesticides (48 compounds), pharmaceuticals (11), industrial (10), preservatives/food additives (3) and personal care products (1). Similar diversity and concentration range of EOCs were observed at the targeted sites, with the addition of drugs of abuse and life-style compounds. EOC detections occurred across young (1–11 yrs. MRT), intermediate (11–50 yrs. MRT) and old (50–250 yrs. MRT) groundwaters with higher concentrations and more types of EOCs detected at sites in the youngest age category. Concentrations of the 73 compounds detected at baseline sites were comparable to those found in overseas groundwaters with 28 compounds measured at concentrations greater than the EU maximum admissible concentration for pesticides. We used the survey results to: review current pesticide monitoring; propose complementary monitoring; identify potential EOC groundwater tracers and identify compounds for which cost-effective national laboratory capability is needed. The Waikato survey results demonstrated ubiquitous occurrence of unmonitored, unregulated EOCs in groundwater and limitations in using targeted approaches to establish monitorin
Kilometer range filamentation
International audienceWe demonstrate for the first time the possibility to generate long plasma channels up to a distance of 1 km, using the terawatt femtosecond T&T laser facility. The plasma density was optimized by adjusting the chirp, the focusing and beam diameter. The interaction of filaments with transparent and opaque targets was studied
Identification of Restricted Subsets of Mature microRNA Abnormally Expressed in Inactive Colonic Mucosa of Patients with Inflammatory Bowel Disease
International audienceBACKGROUND: Ulcerative Colitis (UC) and Crohn's Disease (CD) are two chronic Inflammatory Bowel Diseases (IBD) affecting the intestinal mucosa. Current understanding of IBD pathogenesis points out the interplay of genetic events and environmental cues in the dysregulated immune response. We hypothesized that dysregulated microRNA (miRNA) expression may contribute to IBD pathogenesis. miRNAs are small, non-coding RNAs which prevent protein synthesis through translational suppression or mRNAs degradation, and regulate several physiological processes. METHODOLOGY/FINDINGS: Expression of mature miRNAs was studied by Q-PCR in inactive colonic mucosa of patients with UC (8), CD (8) and expressed relative to that observed in healthy controls (10). Only miRNAs with highly altered expression (>5 or 100 -fold and 0.05-0.19 -fold for over- and under- expression, respectively; 0.00
Impact of Switching From Immediate- or Prolonged-Release to Once-Daily Extended-Release Tacrolimus (LCPT) on Tremor in Stable Kidney Transplant Recipients: The Observational ELIT Study
Once-daily extended-release tacrolimus (LCPT) exhibits increased bioavailability versus immediate-release (IR-TAC) and prolonged release (PR-TAC) tacrolimus. Improvements in tremor were previously reported in a limited number of kidney transplant patients who switched to LCPT. We conducted a non-interventional, non-randomized, uncontrolled, longitudinal, prospective, multicenter study to assess the impact of switching to LCPT on tremor and quality of life (QoL) in a larger population of stable kidney transplant patients. The primary endpoint was change in The Essential Tremor Rating Assessment Scale (TETRAS) score; secondary endpoints included 12-item Short Form Survey (SF-12) scores, tacrolimus trough concentrations, neurologic symptoms, and safety assessments. Subgroup analyses were conducted to assess change in TETRAS score and tacrolimus trough concentration/dose (C0/D) ratio by prior tacrolimus formulation and tacrolimus metabolizer status. Among 221 patients, the mean decrease of TETRAS score after switch to LCPT was statistically significant (p < 0.0001 vs. baseline). There was no statistically significant difference in change in TETRAS score after switch to LCPT between patients who had received IR-TAC and those who had received PR-TAC before switch, or between fast and slow metabolizers of tacrolimus. The overall increase of C0/D ratio post-switch to LCPT was statistically significant (p < 0.0001) and from baseline to either M1 or M3 (both p < 0.0001) in the mITT population and in all subgroups. In the fast metabolizers group, the C0/D ratio crossed over the threshold of 1.05Â ng/mL/mg after the switch to LCPT. Other neurologic symptoms tended to improve, and the SF-12 mental component summary score improved significantly. No new safety concerns were evident. In this observational study, all patients had a significant improvement of tremor, QoL and C0/D ratio post-switch to LCPT irrespective of the previous tacrolimus formulation administered (IR-TAC or PR-TAC) and irrespective from their metabolism status (fast or slow metabolizers)
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