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1.
Arch Toxicol ; 95(3): 1129-1138, 2021 03.
Article in English | MEDLINE | ID: mdl-33398417

ABSTRACT

Systemic increased inflammatory mediators' levels are a hallmark in a plethora of pathological conditions, including thrombotic diseases as the envenomation by Bothrops lanceolatus snake. Multiple organ infarctions, which are not prevented by anticoagulant therapy, are the main cause of death on this envenomation. However, the potential mechanisms involved in these systemic reactions are underexplored. This study aimed to explore the potential systemic events which could contribute to thrombotic reactions on the envenomation by B. lanceolatus in an ex vivo human whole-blood model. B. lanceolatus venom elicited an inflammatory reaction, which was characterized by a strong complement activation, since we detected high C3a, C4a and C5a anaphylatoxins levels. Besides, the venom promoted soluble Terminal Complement Complex (sTCC) assembly. Complement activation was accompanied by intense lipid mediators' release, which included LTB4, PGE2 and TXB2. In addition, in the blood exposed to B. lanceolatus venom, we detected IL-1ß, IL-6 and TNF-α interleukins production. Chemokines, including CCL2, CCL5 and CXCL8 were upregulated in the venom presence. These outcomes show that B. lanceolatus venom causes a strong inflammatory reaction in the blood favoring a potential setting to thrombi formation. Thus, inhibiting inflammatory mediators or their receptors may help in the envenomed patients' management.


Subject(s)
Bothrops , Crotalid Venoms/toxicity , Inflammation Mediators/metabolism , Inflammation/etiology , Animals , Humans , Inflammation/pathology , Inflammation Mediators/blood , Thrombosis/etiology , Thrombosis/pathology
2.
Crit Rev Toxicol ; 49(8): 637-669, 2019 09.
Article in English | MEDLINE | ID: mdl-32009535

ABSTRACT

Corrosive chemical substance ingestions are a major problem, especially in developing countries, but also in developed countries such as the United States, France, and Belgium. Ingestions may be deliberate as suicide attempts (mostly in adolescents and adults) or accidental (mostly in children). The results can be devastating in terms of individual suffering and disability, but also in terms of resource utilization and costs. In developing countries, outcomes may be worse because of limited medical/surgical resources. Common sequelae include gastrointestinal (GI) tract (esophagus, stomach, pylorus, and duodenum) stricture formation, GI tract perforation, and hemorrhage. Systemic effects may also occur, such as disseminated intravascular coagulation (DIC), multi-organ system failure, and sepsis. Various interventions in the acute phase to reduce the severity of injury have been attempted, but there are no large controlled clinical trials to demonstrate efficacy. Dilation therapy in various forms is commonly used for the treatment of strictures and a variety of surgical procedures including esophagectomy and delayed replacement may be required in severe corrosive injury cases.


Subject(s)
Burns, Chemical , Caustics/poisoning , Gastrointestinal Tract , Adolescent , Adult , Child , Female , Humans , Male , Suicide, Attempted
3.
Crit Rev Toxicol ; 48(7): 540-554, 2018 08.
Article in English | MEDLINE | ID: mdl-30226392

ABSTRACT

The objective was to perform a thorough review of published and other available data to elucidate the extent of chemical skin injuries in the US. Chemical skin injuries differ significantly from skin lesions produced by other injury mechanisms, so this review was restricted to the former. Retrieval of relevant published data was performed in PubMed and Google. Other data were retrieved from the American College of Surgeons National Trauma Databank, American Burn Association National Burn Repository, US Department of Labor Bureau of Labor Statistics, websites of all 50 US States Departments of Health, and the National Poison Data System of the American Association of Poison Control Centers. Two areas of significance in disfiguring skin burn injuries and particularly of chemical skin injuries, psychosocial issues and the associated financial burden, have been briefly reviewed. Because of the paucity of published data, international as well as US data have been included. A brief description of an active flushing fluid as an alternative to potable water, Diphoterine® solution, has also been included. Chemical skin injuries generally comprise approximately 2-5% of all skin burns, but sometimes higher percentages have been reported. Data analysis shows that while there are various sources regarding the epidemiology of chemical skin injuries, the total annual number cannot be determined because there is no centralized US national reporting mechanism. Literature and clinical experience demonstrate the importance of chemical skin injuries in USA. Dermal exposures to chemicals can result in mortality and morbidity. Chemical skin injuries can be avoided or ameliorated and preventive advanced measures should be taken to reduce or ameliorate them.


Subject(s)
Burns, Chemical , Skin Diseases , Skin , Burns , Humans , Skin/injuries , United States
4.
Biofouling ; 32(8): 925-34, 2016 09.
Article in English | MEDLINE | ID: mdl-27483985

ABSTRACT

The short-term kinetics of bacterial repopulation were evaluated after chlorination of high-density polyethylene (HDPE) colonized with drinking water biofilms and compared with bare HDPE surfaces. The effect of chlorination was partial as a residual biofilm persisted and was time-limited as repopulation occurred immediately after water resupply. The total number of bacteria reached the same levels on both the bare and chlorinated biofilm-fouled HDPE after a seven-day exposure to drinking water. Due to the presence of a residual biofilm, the hydrophobicity of chlorinated biofilm-fouled surface exhibited much lower adhesion forces (2.1 nN) compared to bare surfaces (8.9 nN). This could explain the rapid repopulation after chlorination, with a twofold faster bacterial accumulation rate on the bare HDPE surface. γ-Proteobacteria dominated the early stages of repopulation of both surfaces and a shift in the dominance occurred over the colonization time. Such observations define a timescale for cleaning frequency in industrial environments and guidelines for a rinsing procedure using drinking water.


Subject(s)
Biofilms/drug effects , Chlorine/pharmacology , Drinking Water/microbiology , Gammaproteobacteria/growth & development , Polyethylene/chemistry , Water Supply/standards , Bacterial Load , Gammaproteobacteria/isolation & purification , Gammaproteobacteria/physiology , Halogenation , Kinetics , Water Microbiology/standards
5.
Front Microbiol ; 15: 1369665, 2024.
Article in English | MEDLINE | ID: mdl-38511008

ABSTRACT

In industrial water systems, the occurrence of biofilm-associated pathogenic free-living amoebae (FLA) such as Naegleria fowleri is a potential hygienic problem, and factors associated with its occurrence remain poorly understood. This study aimed to evaluate the impact of four cooling circuit materials on the growth of N. fowleri in a freshwater biofilm formed at 42°C and under a hydrodynamic shear rate of 17 s-1 (laminar flow): polyvinyl chloride, stainless steel, brass, and titanium. Colonization of the freshwater biofilms by N. fowleri was found to be effective on polyvinyl chloride, stainless steel, and titanium. For these three materials, the ratio of (bacterial prey)/(amoeba) was found to control the growth of N. fowleri. All materials taken together, a maximum specific growth rate of 0.18 ± 0.07 h-1 was associated with a generation time of ~4 h. In contrast, no significant colonization of N. fowleri was found on brass. Therefore, the contribution of copper is strongly suspected.

6.
Cutan Ocul Toxicol ; 30(2): 100-7, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21077748

ABSTRACT

BACKGROUND: Hydrofluoric acid (HF) is particularly dangerous due to the potential for systemic effects and induction of severe skin necrosis through two mechanisms: corrosiveness and local tissue toxicity. In addition, because it is only partially dissociated (pK(a) 3.2), it is capable of penetrating deeply into tissues. There is a lack of experimental studies that objectively characterize the behavior of HF diffusion into human skin, specifically the kinetics of tissue penetration resulting in severe cellular lesions. METHODOLOGY/PRINCIPAL FINDINGS: We describe the cutaneous effects of HF using an established ex vivo human skin model. The diffusion of 70% HF starts within the first minute of contact at the epidermal surface and after 2 min reaches the basal layer. In the subsequent minute, the epidermis is destroyed and lesions appear in the papillary dermis after 4 min. Soon after, damage appears in the upper reticular dermis. Thus, 70% HF needs only 5 min of contact to completely penetrate human skin explants. This experiment is reproducible and corroborates previous studies and clinical effects reported in accidental HF exposures. CONCLUSION/SIGNIFICANCE: This study shows that the management of HF chemical skin exposure is a question of minutes, especially for initial decontamination. These experimental observations could be useful for objectively comparing skin decontamination methods. Further studies should help to confirm these preliminary results.


Subject(s)
Burns, Chemical/pathology , Hydrofluoric Acid/toxicity , Models, Biological , Skin/injuries , Adult , Female , Humans , Skin/pathology , Tissue Culture Techniques
7.
Cutan Ocul Toxicol ; 30(2): 108-15, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21083510

ABSTRACT

BACKGROUND: Hydrofluoric acid (HF) is a small and partially dissociated acid (pK(a) 3.2), able to deeply penetrate into human skin in addition to the corrosiveness of the hydrogen ion (H(+)) and the toxicity of the fluoride ion (F(-)). However, there has been a lack of experimental studies to objectively characterize the results of human HF skin exposure decontamination. METHODOLOGY/PRINCIPAL FINDINGS: A previously established experimental method using a human skin explants ex vivo model (Part 1. Experimental 70% hydrofluoric acid (HF) burns: Histological observations in an established human skin explants ex vivo model) described the lesions that appeared following 70% HF penetration. Within 5 min, 70% HF penetrates to the dermis. Using the same experimental conditions, a comparison study of two different washing protocols was performed: water + topical calcium gluconate (CaG) versus Hexafluorine(®). In these conditions, washing for 15 min with running tap water followed by topical CaG ointment only delayed burn onset, while severe tissue damage appeared later. In contrast, after washing with Hexafluorine(®) over 10 min, no histological lesions developed. These results are in accordance with the results of accidental human industrial case reports. CONCLUSION/SIGNIFICANCE: Amphoteric and hypertonic Hexafluorine(®) can deactivate H(+) and chelate F(-) ions. Based on these results, it should be considered as a promising first-aid decontamination solution to prevent or minimize significant local and systemic consequences of concentrated HF skin exposures.


Subject(s)
Burns, Chemical/therapy , Calcium Gluconate/pharmacology , Emergency Treatment , Fluorine Compounds/pharmacology , Hydrofluoric Acid/toxicity , Water , Adult , Burns, Chemical/pathology , Decontamination , Female , Humans , Models, Biological , Tissue Culture Techniques
8.
Int J Hyg Environ Health ; 233: 113692, 2021 04.
Article in English | MEDLINE | ID: mdl-33592569

ABSTRACT

The aim of the present study was to develop a simple, sensitive, and specific approach to quantifying the SARS-CoV-2 genome in wastewater and to evaluate this approach as a means of epidemiological surveillance. Twelve wastewater samples were collected from a metropolitan area in north-eastern France during April and May 2020. In addition to the quantification of the SARS-CoV-2 genome, F-specific RNA phages of genogroup II (FRNAPH GGII), naturally present in wastewater, were used as an internal process control for the viral concentration and processing of RT-PCR inhibitors. A concentration method was required to allow the quantification of the SARS-CoV-2 genome over the longest possible period. A procedure combining ultrafiltration, phenol-chloroform-isoamyl alcohol purification, and the additional purification of the RNA extracts was chosen for the quantification of the SARS-CoV-2 genome in 100-mL wastewater samples. At the same time, the COVID-19 outbreak was evaluated through patients from the neighbouring University Hospital of Nancy, France. A regular decrease in the concentration of the SARS-CoV-2 genome from ~104 gc/L to ~102 gc/L of wastewater was observed over the eight weeks of the study, during which the population was placed under lockdown. The SARS-CoV-2 genome was even undetectable during one week in the second half of May and present but non-quantifiable in the last sample (28 May). A concordant circulation in the human community was highlighted by virological diagnosis using respiratory samples, which showed a decrease in the number of COVID-19 cases from 677 to 52 per week over the same period. The environmental surveillance of COVID-19 using a reliable viral quantification procedure to test wastewater is a key approach. The real-time detection of viral genomes can allow us to predict and monitor the circulation of SARS-CoV-2 in clinical settings and survey the entire urban human population.


Subject(s)
COVID-19/epidemiology , Disease Outbreaks , Environmental Monitoring/methods , Genome, Viral , SARS-CoV-2/genetics , Wastewater/microbiology , COVID-19/diagnosis , COVID-19/virology , Chemical Precipitation , Cities/epidemiology , France/epidemiology , Hospitals, University , Humans , Ultrafiltration , Viral Proteins/chemistry , Viral Proteins/isolation & purification , Water Microbiology
9.
Microorganisms ; 9(8)2021 Jul 27.
Article in English | MEDLINE | ID: mdl-34442682

ABSTRACT

The gut microbiota is a complex and dynamic ecosystem whose balance and homeostasis are essential to the host's well-being and whose composition can be critically affected by various factors, including host stress. Parabacteroides distasonis causes well-known beneficial roles for its host, but is negatively impacted by stress. However, the mechanisms explaining its maintenance in the gut have not yet been explored, in particular its capacities to adhere onto (bio)surfaces, form biofilms and the way its physicochemical surface properties are affected by stressing conditions. In this paper, we reported adhesion and biofilm formation capacities of 14 unrelated strains of P. distasonis using a steam-based washing procedure, and the electrokinetic features of its surface. Results evidenced an important inter-strain variability for all experiments including the response to stress hormones. In fact, stress-induced molecules significantly impact P. distasonis adhesion and biofilm formation capacities in 35% and 23% of assays, respectively. This study not only provides basic data on the adhesion and biofilm formation capacities of P. distasonis to abiotic substrates but also paves the way for further research on how stress-molecules could be implicated in P. distasonis maintenance within the gut microbiota, which is a prerequisite for designing efficient solutions to optimize its survival within gut environment.

10.
Cutan Ocul Toxicol ; 29(2): 110-5, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20233016

ABSTRACT

Tetramethylammonium hydroxide (TMAH), used in microelectronic industries and research and development, has both corrosive properties and systemic toxicity. Two fatal TMAH occupational exposure cases have been published. Studies comparing initial TMAH decontamination with Diphoterine versus tap water were performed: an in vitro pH titration study and an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) in vitro cytotoxicity cell viability assay. For pH normalization, 17 times more tap water than Diphoterine was required. In the cytotoxicity test, two-thirds of the cells remained viable after Diphoterine washing, compared with only one-third after tap water washing (p < .001). Diphoterine washing is a promising TMAH decontamination method.


Subject(s)
Burns, Chemical/drug therapy , Occupational Exposure/adverse effects , Ophthalmic Solutions/therapeutic use , Quaternary Ammonium Compounds/toxicity , Skin Diseases/chemically induced , Skin Diseases/prevention & control , Burns, Chemical/pathology , Cell Line , Cell Survival/drug effects , Coloring Agents , Epidermis/pathology , Humans , Organic Chemicals/therapeutic use , Skin/pathology , Skin Diseases/pathology , Tetrazolium Salts , Therapeutic Irrigation , Thiazoles , Water
11.
Cutan Ocul Toxicol ; 28(4): 149-56, 2009.
Article in English | MEDLINE | ID: mdl-19888884

ABSTRACT

Diphoterine (Laboratoire Prevor, Valmondois, France) is an active, amphoteric, polyvalent, chelating, slightly hypertonic decontamination solution for chemical splashes to the skin and eyes. It chemically binds a large number of chemical substances present on the skin surface without causing a significant release of heat (exothermic reactions). Because of its amphoteric properties, it can bind chemically opposite substances such as acids and bases or oxidizers and reducing agents. No adverse effects have been observed in an ongoing postmarketing surveillance program during many years of use in European industrial facilities. Diphoterine has more recently been used in hospitals for delayed management of chemical burns to the skin and eyes. There is interest in having protocols for both immediate and delayed diphoterine use for skin decontamination. Whereas studies of diphoterine efficacy, clinical and in vitro or ex vivo, have been published or are in the process of being prepared for publication, no review has yet been published focusing solely on the safety of this decontamination solution. Therefore, all available studies on the safety of diphoterine are described here, including recent studies demonstrating no harmful effects on the skin. Diphoterine can be used, even on damaged skin, without toxic, irritant, allergenic, or sensitizing effects.


Subject(s)
Burns, Chemical/therapy , Decontamination/methods , Eye Burns/therapy , Skin Diseases/therapy , Administration, Topical , Animals , Eye Burns/chemically induced , Humans , Organic Chemicals/administration & dosage , Organic Chemicals/adverse effects , Organic Chemicals/therapeutic use , Risk Assessment , Skin Diseases/chemically induced , Toxicity Tests , Treatment Outcome
12.
Ultrason Sonochem ; 52: 41-49, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30718177

ABSTRACT

A device generating low-frequency and low-intensity ultrasound waves was used for mitigating biofilm accumulation and scaling. Two systems were tested: a lab-scale plate heat exchanger operated with continuously recycled water and a continually fed flow-through drinking water pilot used for mimicking water circulation in pipes. Initial deposition of bacterial cells was not prevented by ultrasound wave treatment. However, whatever the tested system, both further calcium carbonate deposition and biofilm growth were markedly inhibited. Biofilms formed in reactors subjected to low-frequency and low-intensity ultrasound waves were weakly attached to the material. Even though the activity of bacteria was affected as shown by their lower cultivability, membrane permeability did not appear compromised. Ultrasound technology sounds very promising in both the mitigation of drinking water biofilm and carbonate accumulation.


Subject(s)
Biofilms/growth & development , Carbonates/analysis , Drinking Water/chemistry , Drinking Water/microbiology , Sonication/instrumentation , Carbonates/chemistry , Hot Temperature
13.
Bone ; 42(3): 554-64, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18178142

ABSTRACT

Fetal bone cells were shown to have an interesting potential for therapeutic use in bone tissue engineering due to their rapid growth rate and their ability to differentiate into mature osteoblasts in vitro. We describe hereafter their capability to promote bone repair in vivo when combined with porous scaffolds based on poly(l-lactic acid) (PLA) obtained by supercritical gas foaming and reinforced with 5 wt.% beta-tricalcium phosphate (TCP). Bone regeneration was assessed by radiography and histology after implantation of PLA/TCP scaffolds alone, seeded with primary fetal bone cells, or coated with demineralized bone matrix. Craniotomy critical size defects and drill defects in the femoral condyle in rats were employed. In the cranial defects, polymer degradation and cortical bone regeneration were studied up to 12 months postoperatively. Complete bone ingrowth was observed after implantation of PLA/TCP constructs seeded with human fetal bone cells. Further tests were conducted in the trabecular neighborhood of femoral condyles, where scaffolds seeded with fetal bone cells also promoted bone repair. We present here a promising approach for bone tissue engineering using human primary fetal bone cells in combination with porous PLA/TCP structures. Fetal bone cells could be selected regarding osteogenic and immune-related properties, along with their rapid growth, ease of cell banking and associated safety.


Subject(s)
Bone Regeneration/physiology , Bone and Bones/cytology , Ceramics/metabolism , Fetus/anatomy & histology , Lactic Acid/metabolism , Polymers/metabolism , Tissue Engineering , Tissue Scaffolds , Animals , Biocompatible Materials/chemistry , Biocompatible Materials/metabolism , Bone and Bones/pathology , Calcium Phosphates/chemistry , Calcium Phosphates/metabolism , Cells, Cultured , Ceramics/chemistry , Female , Humans , Implants, Experimental , Lactic Acid/chemistry , Polyesters , Polymers/chemistry , Random Allocation , Rats , Rats, Sprague-Dawley , Rats, Wistar , Surface Properties
14.
Environ Sci Pollut Res Int ; 25(30): 30497-30507, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30168112

ABSTRACT

Human adenoviruses (HAdVs) are a major cause of infection and have been proposed as viral indicators of water quality. Human noroviruses (NoV) are the main cause of viral acute gastroenteritis. Quantitative data on the environmental prevalence of both viruses are needed. The genomes of HAdVs enteric adenovirus type 41 (HAdV41) and noroviruses of genogroups I and II (NoV GGI and GGII) were quantified over a 6-month period in a river located in north-eastern France. The samples were collected downstream from the discharge of a wastewater treatment plant. The viruses were concentrated using a glass wool method and the viral genomes were quantified using digital droplet PCR (ddPCR). All river water samples (15/15) were positive for the genomes of HAdVs, HAdV41, NoV GGI and NoV GGII. Concentrations of HAdVs, HAdV41 and NoV GII genomes were similar and HAdV41 represented ~ 80% of HAdVs. Infectious HAdVs were quantified in these samples using an integrated cell culture-quantitative PCR method (ICC-qPCR); they were detected in 93% (14/15) and quantified in 53% (8/15) of the samples. Thus, infectious HAdVs represented 0.3 to 12.2% of total HAdV particles detected by ddPCR. Infectious HAdV41 particles were found in 73% (11/15) of the samples. This common presence of pathogenic enteric viruses underlines the impact of wastewater discharge on quality of surface waters and may constitute a threat for human health. The relative abundance of genome of HAdV41 underlines the need for studies focusing on the specific detection of its infectious forms along water cycle.


Subject(s)
Adenoviruses, Human/isolation & purification , Norovirus/isolation & purification , Rivers/virology , Water Microbiology , Adenoviruses, Human/genetics , Environmental Monitoring/methods , France , Humans , Real-Time Polymerase Chain Reaction
15.
J Immunol Res ; 2018: 3462136, 2018.
Article in English | MEDLINE | ID: mdl-30116749

ABSTRACT

Bothrops lanceolatus snake venom causes systemic thrombotic syndrome but also local inflammation involving extensive oedema, pain, and haemorrhage. Systemic thrombotic syndrome may lead to fatal pulmonary embolism and myocardial and cerebral infarction. Here, we investigated the ability of B. lanceolatus venom to activate the Complement system (C) in order to improve the understanding of venom-induced local inflammation. Data presented show that B. lanceolatus venom is able to activate all C-pathways. In human serum, the venom strongly induced the generation of anaphylatoxins, such as C5a and C4a, and the Terminal Complement complex. The venom also induced cleavage of purified human components C3, C4, and C5, with the production of biologically active C5a. Furthermore, the venom enzymatically inactivated the soluble C-regulator and the C1-inhibitor (C1-INH), and significantly increased the expression of bound C-regulators, such as MCP and CD59, on the endothelial cell membrane. Our observations that B. lanceolatus venom activates the three Complement activation pathways, resulting in anaphylatoxins generation, may suggest that this could play an important role in local inflammatory reaction and systemic thrombosis caused by the venom. Inactivation of C1-INH, which is also an important inhibitor of several coagulation proteins, may also contribute to inflammation and thrombosis. Thus, further in vivo studies may support the idea that therapeutic management of systemic B. lanceolatus envenomation could include the use of Complement inhibitors as adjunct therapy.


Subject(s)
Bothrops , Complement Activation/drug effects , Crotalid Venoms/toxicity , Animals , Humans , Martinique
16.
Toxicon ; 150: 253-260, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29890230

ABSTRACT

Snakes belonging to the genus Naja (Elapid family), also known as "spitting cobras", can spit venom towards the eyes of the predator as a defensive strategy, causing painful and potentially blinding ocular envenoming. Venom ophthalmia is characterized by pain, hyperemia, blepharitis, blepharospasm and corneal erosions. Elapid venom ophthalmia is not well documented and no specific treatment exists. Furthermore, accidental ejection of venom by non-spitting vipers, as Bothrops, also occurs. The Ex vivo Eye Irritation Test model (EVEIT) has enabled important progress in the knowledge of chemical ocular burns. Considering the lack of experimental animal model, we adapted the EVEIT to study venom ophthalmia mechanisms. Ex vivo rabbit corneas were exposed to venoms from spitting (Naja mossambica, Naja nigricollis) and non-spitting (Naja naja, Bothrops jararaca and Bothrops lanceolatus) snakes, and rinsed or not with water. The corneal thickness and the depth of damage were assessed using high-resolution optical coherence tomography (HR-OCT) imaging and histological analysis. All Naja venoms induced significant corneal edema, collagen structure disorganization and epithelial necrosis. Corneas envenomed by African N. mossambica and N. nigricollis venoms were completely opaque. Opacification was not observed in corneas treated with venoms from non-spitting snakes, such as the Asian cobra, N. naja, and the vipers, B. jararaca and B. lanceolatus. Moreover, Bothrops venoms were able to damage the epithelium and cause collagen structure disorganization, but not edema. Immediate water rinsing improved corneal status, though damage and edema could still be observed. In conclusion, the present study shows that the EVEIT model was successfully adapted to set a new experimental ex vivo animal model of ophthalmia, caused by snake venoms, which will enable to explore new therapies for venom ophthalmia.


Subject(s)
Cornea/drug effects , Elapid Venoms/toxicity , Toxicity Tests/methods , Animals , Elapidae , Rabbits
17.
Materials (Basel) ; 11(11)2018 Nov 01.
Article in English | MEDLINE | ID: mdl-30388867

ABSTRACT

ZnO nanorods (NRs) with an average length and diameter of 186 and 20 nm, respectively, were prepared through a mild solvothermal route and used as photocatalysts either as dispersed powder or immobilized on glass slides. The ZnO NRs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Dispersed ZnO NRs and, to a lesser extent, immobilized ZnO NRs were demonstrated to exhibit high photocatalytic activity under simulated sunlight of low intensity (5.5 mW/cm²) both for the degradation of the Orange II dye and for Escherichia coli bacterial decontamination (2.5-fold survival decrease after 180 min irradiation for immobilized NRs). SEM, atomic force microscopy (AFM), fluorescence spectroscopy, and epifluorescence microscopy demonstrate that cell surface damages are responsible of bacterial inactivation. The immobilized ZnO NRs could be reused up to five times for bacterial decontamination at comparable efficiency and therefore have great potential for real environmental applications.

18.
J Biomed Mater Res A ; 83(1): 41-51, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17377968

ABSTRACT

Bioresorbable scaffolds made of poly(L-lactic acid) (PLA) obtained by supercritical gas foaming were recently described as suitable for tissue engineering, portraying biocompatibility with primary osteoblasts in vitro and interesting mechanical properties when reinforced with ceramics. The behavior of such constructs remained to be evaluated in vivo and therefore the present study was undertaken to compare different PLA/ceramic composite scaffolds obtained by supercritical gas foaming in a critical size defect craniotomy model in Sprague-Dawley rats. The host-tissue reaction to the implants was evaluated semiquantitatively and similar tendencies were noted for all graft substitutes: initially highly reactive but decreasing with time implanted. Complete bone-bridging was observed 18 weeks after implantation with PLA/ 5 wt % beta-TCP (PLA/TCP) and PLA/5 wt % HA (PLA/HA) scaffolds as assessed by histology and radiography. We show here for the first time that this solvent-free technique provides a promising approach in tissue engineering demonstrating both the biocompatibility and osteoconductivity of the processed structures in vivo.


Subject(s)
Biocompatible Materials/chemistry , Ceramics/chemistry , Gases/metabolism , Implants, Experimental , Lactic Acid/metabolism , Polymers/metabolism , Skull/physiology , Wound Healing , Animals , Biocompatible Materials/metabolism , Blood Cell Count , Body Weight , Bone Substitutes/metabolism , Ceramics/metabolism , Cytokines/blood , Polyesters , Radiography , Rats , Rats, Sprague-Dawley , Skull/diagnostic imaging , Skull/pathology , Skull/ultrastructure , Tissue Engineering
19.
Water Res ; 109: 155-163, 2017 Feb 01.
Article in English | MEDLINE | ID: mdl-27883920

ABSTRACT

Adsorption of organic macromolecules onto surfaces in contact with waters forms a so-called conditioning film and induces modifications of the surface properties. Here, we characterized conditioning films formed onto two hydrophobic materials (used as pipe liner) and immersed for 24 h in tap water. Using combination of atomic force microscopy (AFM), and chemical force microscopy (CFM), we detected some changes in roughness and hydrophilic/hydrophobic balance of the surface of the tested coupons, and also the deposition of numerous organic polymers (few millions/cm2) randomly distributed on the surface. The maximum molecular extension of these organic polymers was in the range of 250-1250 nm according to the tested materials. Systematic analysis of the force curves with the theoretical models (WLC and FJC) allowed determining the proportion of rupture events related to the unfolding of both polysaccharide and polypeptide segments, which represented 75-80% and 20-25% of the analyzed curves, respectively. The number of autochthonous drinking water bacteria, which attached to the material within the same period of time was 10000-folds lower than the detected number of polymers attached to the surface. Even in drinking water systems with relatively low organic matter (dissolved organic carbon < 1.1 mg/L), the potential of formation of a conditioning biofilm is important.


Subject(s)
Drinking Water , Surface Properties , Biofilms , Hydrophobic and Hydrophilic Interactions , Microscopy, Atomic Force
20.
Toxins (Basel) ; 9(8)2017 08 07.
Article in English | MEDLINE | ID: mdl-28783135

ABSTRACT

Bothrops lanceolatus, commonly named 'Fer-de-Lance', is an endemic snake of the French Caribbean Island of Martinique. Envenomations by B. lanceolatus present clinical aspects characterized by systemic thrombotic syndrome and important local inflammation, involving edema and pain but limited hemorrhage. To investigate mechanisms of venom-induced inflammation, B. lanceolatus venom was characterized, its cross-reactivity with bothropic antivenom explored, its cytotoxicity on human keratinocytes and vascular cells, and the production of cytokines and chemokines were analyzed. We used electrophoretic separation, zymography, colorimetric or fluorimetric enzymatic assays, and immunochemical assays. Therapeutic South American bothropic antivenom cross-reacted with B. lanceolatus venom and completely or partially abolished its PLA2, hyaluronidase, and proteolytic activities, as well as its cytotoxicity for keratinocytes. The substrate specificity of B. lanceolatus venom proteases was emphasized. B. lanceolatus venom cytotoxicity was compared to the B. jararaca venom. Both venoms were highly cytotoxic for keratinocytes (HaCaT), whereas B. lanceolatus venom showed particularly low toxicity for endothelial cells (EAhy926). Patterns of cytokine and chemokine production by cells exposed to the venoms were highly pro-inflammatory. Thus, the results presented here show that B. lanceolatus venom toxins share important antigenic similarities with South American Bothrops species toxins, although their proteases have acquired particular substrate specificity. Moreover, the venom displays important cytotoxic and pro-inflammatory action on human cell types such as keratinocytes and endothelial cells, which are important players in the local and systemic compartments affected by the envenomation.


Subject(s)
Bothrops , Crotalid Venoms/toxicity , Animals , Antivenins/pharmacology , Cell Line , Cell Survival/drug effects , Cytokines/metabolism , Endothelial Cells/drug effects , Endothelial Cells/metabolism , Humans , Hyaluronoglucosaminidase/metabolism , Intercellular Adhesion Molecule-1/metabolism , Keratinocytes/drug effects , Keratinocytes/metabolism , Phospholipases/metabolism , Proteolysis , Snake Bites , Thromboplastin/metabolism
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