Improving quality in nanoparticle-induced cytotoxicity testing by a tiered inter-laboratory comparison study

The quality and relevance of nanosafety studies constitute major challenges to ensure their key role as a supporting tool in sustainable innovation, and subsequent competitive economic advantage. However, the number of apparently contradictory and inconclusive research results has increased in the past few years, indicating the need to introduce harmonized protocols and good practices in the nanosafety research community. Therefore, we aimed to evaluate if best-practice training and inter-laboratory comparison (ILC) of performance of the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay for the cytotoxicity assessment of nanomaterials among 15 European laboratories can improve quality in nanosafety testing. We used two well-described model nanoparticles, 40-nm carboxylated polystyrene (PS-COOH) and 50-nm amino-modified polystyrene (PS-NH2). We followed a tiered approach using well-developed standard operating procedures (SOPs) and sharing the same cells, serum and nanoparticles. We started with determination of the cell growth rate (tier 1), followed by a method transfer phase, in which all laboratories performed the first ILC on the MTS assay (tier 2). Based on the outcome of tier 2 and a survey of laboratory practices, specific training was organized, and the MTS assay SOP was refined. This led to largely improved intra- and inter-laboratory reproducibility in tier 3. In addition, we confirmed that PS-COOH and PS-NH2 are suitable negative and positive control nanoparticles, respectively, to evaluate impact of nanomaterials on cell viability using the MTS assay. Overall, we have demonstrated that the tiered process followed here, with the use of SOPs and representative control nanomaterials, is necessary and makes it possible to achieve good inter-laboratory reproducibility, and therefore high-quality nanotoxicological data.Web of Science108art. no. 143

Arguments in Favour of a Consequential Component in Late Effects among Irradiated laryngeal Cancer Patients

peer reviewedHaving previously quantified late effects of a split-course hypofractionated radiotherapy given to full dose among larynx cancer patients, we investigated the presence of a consequential component in this population. One months after irradiation completion patients prone to develop late effects have exhibited an acute toxicity score 3 times higher than late symptoms free patients. At two months follow-up the difference is still more significant with a fourfold increase. Our study brings arguments in favour of a consequential component in positive LENT score patients

How I Treat...Oropharyngeal Mucositis Associated with Radiotherapy for Head and Neck Cancer

peer reviewedOral mucositis the major acute effect of head and neck radiotherapy. According to the degree, irradiation may be compromised in dose and overall time with consequences on outcome. Up to now there is no standard accepted protocol. A strict program of local and general hygiene is mandatory. Analgesics are often required. Amifostine acts as a protector of salivary glands GM-CSF and G-CSF stimulate proliferation of mucosal basal cells. Sucralfate plays a barrier role. Camomile plant extract is anti-inflammatory, well tolerated and cheap. Povidone-iodine is better than chlorhexidine as an antiseptic agent. PTA lozenges with polymixin E, tobramycin and amphotericin B showed a marked power of selective microbial decontamination.RÉSUMÉ : La mucite bucco-pharyngée constitue l’effet secondaire aigu majeur d’une radiothérapie cervico-faciale. Elle est plus marquée en cas de fractionnement accéléré ou de chimiothérapie concomitante et peut conduire à une interruption ou un arrêt du traitement préjudiciables à son résultat. Il n’existe pas, actuellement, de protocole standard codifié. Les mesures préventives et thérapeutiques se fondent sur les mécanismes pathogéniques impliqués : atteinte radique des cellules prolifératives de la couche basale de la muqueuse, réaction inflammatoire surajoutée, perte de l’effet protecteur de la salive et colonisation microbienne de la cavité buccale. Un programme strict d’hygiène locale et générale est recommandé de même que la prescription d’antalgiques est souvent requise. Protégeant les glandes salivaires, l’amifostine exerce indirectement une influence bénéfique. Les facteurs de croissance de type GM-CSF et G-CSF favorisent la cicatrisation par stimulation cellulaire. Le rôle de barrière du sucralfate est confirmé. Par son bon effet anti-inflammatoire local, son inoccuité et son faible coût, l’extrait de camomille possède une place établie. La supériorité de la polyvidone iodée sur la chlorhexidine est largement démontrée en ce qui concerne l’action antiseptique et la tolérance. Une association de polymixine E, de tobramycine et d’amphotéricine B en pastilles a montré son pouvoir de décontamination microbienne sélective

Mandibular Osteoradionecrosis: Sword of Damocles of Radiotherapy for Head and Neck Cancers?

peer reviewedRÉSUMÉ : Dotée d’une réelle efficacité, la radiothérapie des cancers cervico-faciaux peut toutefois être à l’origine de complications sévères. Heureusement peu fréquente, l’ostéoradionécrose mandibulaire en constitue une des plus redoutables. Sa pathogénie relève d’altérations radiques au niveau de la muqueuse, de l’os et des glandes salivaires. Les facteurs de risque tiennent au patient, à la tumeur ainsi qu’aux modalités thérapeutiques. Une cascade d’événements prenant son origine dans l’hyposialie conduit à la nécrose osseuse via le développement de caries extensives et le traumatisme lié à l’extraction dentaire. Une prévention efficace existe, fondée sur une mise en ordre buccale préalablement à l’irradiation, sur des mesures hygiéno-diététiques et la pratique stricte de la fluoruration. Certains traitements médicaux peuvent stabiliser le processus. L’oxygénothérapie hyperbare exerce un effet bénéfique incontestable. Dans les cas les plus graves, une chirurgie reconstructrice par lambeau osseux libre microvascularisé constitue l’ultime recours pour restaurer tant la fonction que l’aspect cosmétique. Rapportant un cas clinique, l’importance de la bonne observance par le patient des principes de prévention est souligné. Parallèlement, l’accent est mis sur la nécessité d’une surveillance régulière exercée par le radiothérapeute afin d’éviter les conséquences gravissimes qui peuvent être celles de l’ostéoradionécrose mandibulaire

Possible role of granulocyte colony-stimulating factor (Filgastrim) in the management of radiation induced oral mucositis and dysphagia

peer reviewedA pilot study was conducted in order to investigate the possible influence of GCSF on acute radiotherapy oral side effects. Among irradiated oral cavity and oropharynx cancer patients , both grades of mucositis and dysphagia were significantly decreased as compared to controls receiving conventional support. GCSF might improve compliance to radiotherapy in such clinical conditions

CoCl2, a chemical inducer of hypoxia-inducible factor-1, and hypoxia reduce apoptotic cell death in hepatoma cell line HepG2.

HIF-1 (hypoxia-inducible factor-1) is the major transcription factor that is specifically activated during hypoxia. This transcription factor is composed of two subunits: HIF-1alpha and ARNT (aryl hydrocarbon receptor nuclear translocator). ARNT is constitutively expressed, whereas HIF-1alpha is targeted to proteasome degradation by ubiquitination during normoxia. In hypoxia, HIF-1alpha is stabilized and translocates to the nucleus, where it binds to ARNT. The active HIF-1 induces expression of various genes whose products play an adaptive role to the new conditions induced by hypoxia. Besides the role played by HIF-1 in the adaptation to hypoxia, recent data describe a possible role for HIF-1 in the modulation of apoptosis. According to some authors, hypoxia induces apoptosis. However, it has also been reported that hypoxia could protect cells against apoptotic cell death induced by various agents such as serum deprivation and incubation in the presence of chemotherapy agents. These contradictory data suggest that HIF-1 could display either a proapoptotic or an antiapoptotic role according to the conditions. In order to study how HIF-1 can modulate apoptosis, we studied whether hypoxia or cobalt chloride, a chemical inducer of HIF-1, could influence apoptosis induced by tert-butyl hydroperoxide (t-BHP), serum deprivation, or both in hepatoma cell line HepG2. HepG2 cells were incubated 8 hours under normoxia or hypoxia in the presence of t-BHP with or without CoCl2. CoCl2 reduced the apoptotic death of HepG2 cells induced by t-BHP and serum deprivation, as measured by DNA fragmentation. This effect was confirmed by measurement of the caspase activity. Moreover, hypoxia also prevented t-BHP- or serum deprivation-induced DNA fragmentation and caspase activation-however, to a lower extent than CoCl2. These different data suggest a possible antiapoptotic role of HIF-1. More experiments are needed to define if HIF-1 actually plays an active role in cell death protection and to determine the exact mechanism underlying this effect

Possible Role of Granulocyte Colony-stimulating Factor (Filgrastim) in the Management of Radiation Induced Oral Mucositis and Dysphagia

peer reviewedA possible benefit of GCSF was investigated among head and neck cancer patients receiving a split-course hypofractionated radiotherapy. Parameters taken in consideration of mucosal side-effects were grades 0 to 5 mucositis, grades 0 to 5 dysphagia and 3 degrees of global intolerance summing the two former items. GCSF was given for 6 consecutive days at mid- and end of treatment. All the mentioned criterias were significantly shifted towards better tolerance as compared to the untreated group