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Advances in genetic and genomic research continue to increase our knowledge of hereditary diseases, and an increasing number of them are being attributed to aberrant splicing, thus representing ideal targets for RNA modulation therapies. New strategies to skip or re-include exons during the splicing process have emerged and are now widely evaluated in the clinic. Several drugs have recently been approved in particular for the treatment of Duchenne muscular dystrophy and spinal muscular atrophy. Among these molecules, antisense oligonucleotides, or ASOs, have gained increasing interest and have constantly been improved over the years through chemical modifications and design. However, their limited biodistribution following systemic administration still represents a major hurdle and the development of more potent alternative chemistries or new delivery systems has become a very active line of research in the past few years. In parallel, the use of small molecules with excellent biodistribution properties or of viral vectors to convey antisense sequences is also being investigated. In this review, we summarize the recent advances in splicing therapies through two examples of neuromuscular diseases and we discuss their main benefits and current limitations.Les approches thérapeutiques de modulation de l’épissage - Avancées et perspectives.Les avancées en recherches génétique et génomique ne cessent d’accroître nos connaissances des maladies héréditaires. Un nombre croissant de ces maladies relève d’épissages aberrants qui représentent des cibles idéales pour les approches correctives centrées sur l’ARN. De nouvelles stratégies, en particulier médicamenteuses, visant à exclure ou à ré-inclure des exons lors du processus d’épissage, ont ainsi émergé et plusieurs molécules ont récemment obtenu des autorisations de mise sur le marché, notamment pour le traitement de la dystrophie musculaire de Duchenne et de l’amyotrophie spinale, suscitant de plus en plus d’intérêt et d’espoir. Parmi ces molécules, les oligonucléotides antisens, ou ASO, ont connu un réel essor et font l’objet de progrès constants en matière de modifications chimiques et de conception. Toutefois, leur biodistribution après administration par voie générale demeure souvent limitée, et le développement de chimies alternatives plus performantes et de nouveaux systèmes d’adressage est devenu un axe de recherche très actif. En parallèle, l’utilisation de petites molécules présentant une excellente biodistribution, ou de vecteurs viraux pour véhiculer les séquences antisens, est également explorée. Dans cette Synthèse, nous présentons les dernières avancées de ces approches de modulation d’épissage à travers deux exemples de maladies neuromusculaires. Nous discutons de leurs avantages et des principales limitations actuelles.

The ongoing COVID-19 pandemic comprises a total of more than 2,350,000 cases and 160,000 deaths. The interest in anti-coronavirus drug development has been limited so far and effective methods to prevent or treat coronavirus infections in humans are still lacking. Urgent action is needed to fight this fatal coronavirus infection by reducing the number of infected people along with the infection contagiousness and severity. Since the beginning of the COVID-19 outbreak several weeks ago, we observe in GHU PARIS PsychiatrieNeurosciences (Sainte-Anne hospital, Paris, France) a lower prevalence of symptomatic and severe forms of COVID-19 infections in psychiatric patients (∼4%) compared to health care professionals (∼14%). Similar observations have been noted in other psychiatric units in France and abroad. Our hypothesis is that psychiatric patients could be protected from severe forms of COVID-19 by their psychotropic treatments. Chlorpromazine (CPZ) is a phenothiazine derivative widely used in clinical routine in the treatment of acute and chronic psychoses. This first antipsychotic medication has been discovered in 1952 by Jean Delay and Pierre Deniker at Sainte-Anne hospital. In addition, to its antipsychotic effects, several in vitro studies have also demonstrated a CPZ antiviral activity via the inhibition of clathrin-mediated endocytosis. Recently, independent studies revealed that CPZ is an anti-MERS-CoV and an anti-SARS-CoV-1 drug. In comparison to other antiviral drugs, the main advantages of CPZ lie in its biodistribution: (i) preclinical and clinical studies have reported a high CPZ concentration in the lungs (20-200 times higher than in plasma), which is critical because of the respiratory tropism of SARS-CoV-2; (ii) CPZ is highly concentrated in saliva (30-100 times higher than in plasma) and could therefore reduce the contagiousness of COVID-19; (iii) CPZ can cross the blood-brain barrier and could therefore prevent the neurological forms of COVID-19.Our hypothesis is that CPZ could decrease the unfavorable evolution of COVID-19 infection in oxygen-requiring patients without the need for intensive care, but also reduce the contagiousness of SARS-CoV-2. At this end, we designed a pilot, phase III, multicenter, single blind, randomized controlled clinical trial. Efficacy of CPZ will be assessed according to clinical, biological and radiological criteria. The main objective is to demonstrate a shorter time to response (TTR) to treatment in the CPZ+standard-of-care (CPZ+SOC) group, compared to the SOC group. Response to treatment is defined by a reduction of at least one level of severity on the WHO-Ordinal Scale for Clinical Improvement (WHO-OSCI). The secondary objectives are to demonstrate in the CPZ+SOC group, compared to the SOC group: (A) superior clinical improvement; (B) a greater decrease in the biological markers of viral attack by SARS-CoV-2 (PCR, viral load); (C) a greater decrease in inflammatory markers (e.g. CRP and lymphopenia); (D) a greater decrease in parenchymal involvement (chest CT) on the seventh day post-randomization; (E) to define the optimal dosage of CPZ and its tolerance; (F) to evaluate the biological parameters of response to treatment, in particular the involvement of inflammatory cytokines. Patient recruitment along with the main and secondary objectives are in line with WHO 2020 COVID-19 guidelines.This repositioning of CPZ as an anti-SARS-CoV-2 drug offers an alternative and rapid strategy to alleviate the virus propagation and the infection severity and lethality. This CPZ repositioning strategy also avoids numerous developmental and experimental steps and can save precious time to rapidly establish an anti-COVID-19 therapy with well-known, limited and easy to manage side effects. Indeed, CPZ is an FDA-approved drug with an excellent tolerance profile, prescribed for around 70 years in psychiatry but also in clinical routine in nausea and vomiting of pregnancy, in advanced cancer and also to treat headaches in various neurological conditions. The broad spectrum of CPZ treatment - including antipsychotic, anxiolytic, antiemetic, antiviral, immunomodulatory effects along with inhibition of clathrin-mediated endocytosis and modulation of blood-brain barrier - is in line with the historical French commercial name for CPZ, i.e. LARGACTIL, chosen as a reference to its "LARGe ACTion" properties. The discovery of those CPZ properties, as for many other molecules in psychiatry, is both the result of serendipity and careful clinical observations. Using this approach, the field of mental illness could provide innovative therapeutic approaches to fight SARS-CoV-2.

Many neurodegenerative or tumor brain pathologies should be able to benefit from the impressive medicinal advances that represent therapeutic antibodies. Unfortunately, many failures have been observed with antibodies whose targets are in the brain parenchyma due to their very low brain distribution. The blood-brain barrier (BBB) that exhibits extremely selective and restrictive properties is responsible for the low brain penetration of high-molecular mass molecules including therapeutic antibodies. The objective of this article is to present the properties of the BBB and the latest advances in the engineering of new antibody formats to possibly improve their brain distribution.Améliorer le ciblage tissulaire des anticorps thérapeutiques par de nouveaux formats - L’exemple de la barrière hémato-encéphalique.De nombreuses pathologies cérébrales neurodégénératives ou tumorales devraient pourvoir bénéficier des progrès thérapeutiques impressionnants des anticorps médicaments. Malheureusement, en raison de leur très faible passage dans le cerveau, de nombreux développements cliniques d’anticorps dont la cible thérapeutique se situe dans le parenchyme cérébral ont été arrêtés par manque d’efficacité. La barrière hémato-encéphalique (BHE), douée de propriétés extrêmement sélectives et restrictives, est à l’origine de la faible pénétration cérébrale des molécules de haute masse moléculaire, telles que les anticorps thérapeutiques. L’objectif de cette revue est de présenter les propriétés de la BHE et les dernières avancées dans le domaine de l’ingénierie de nouveaux formats d’anticorps susceptibles d’améliorer leur passage intracérébral.

Background: Cetuximab (CTX) is a glycosylated anti-EGFR monoclonal antibody of great interest in the treatment of non-melanoma skin cancers. Its intravenous administration is associated with severe side effects. This is the first report on the noninvasive iontophoretic-targeted topical delivery of CTX to skin. Methods: Iontophoretic transport of CTX (0.5 mA/cm2) was studied as a function of formulation pH (4, 5.5 and 7) and duration of current application (2, 4 and 8 h). CTX cutaneous biodistribution was determined; electrotransport mechanisms and penetration pathways were investigated. Results: Electrophoretic mobility measurements of CTX isoforms and co-iontophoresis of acetaminophen at each pH demonstrated that CTX electrotransport was due to electroosmosis: despite an ~8-fold reduction in charge, CTX skin deposition was greater at pH 7 than pH 4 (8.974 ± 1.952 and 0.482 ± 0.165 μg/mm3) – consistent with the increased electroosmotic flow at pH 7. Iontophoresis of an Alex488-CTX conjugate showed that skin penetration occurred by the intercellular and follicular routes. Therapeutic concentrations of CTX in the viable epidermis, upper dermis and lower dermis were achieved following iontophoresis for 2, 4 and 8 h, respectively. Conclusion: The results demonstrate the topical delivery of a 152 kDa monoclonal antibody into skin in a targeted, controlled and entirely noninvasive manner.

A newly developed technique allows the analysis of gene expression within tissues at near-cellular resolution. This opens a whole range of applications and will be a major ingredient of future studies.

National audience; We reviewed the three reference toxicokinetic studies commonly used to suggestinnocuity of aluminum (Al)-based adjuvants. A single experimental study was carried out usingisotopic26Al (Flarend et al., 1997). This study ignored adjuvant cell capture. It was conductedover a short period of time (28 days) and used only two rabbits per adjuvant. At the endpoint,Al retention was 78% for aluminum phosphate and 94% for aluminum hydroxide, both resultsbeing incompatible with quick elimination of vaccine-derived Al in urines. Tissue distributionanalysis omitted three important retention sites: the injected muscle, the draining lymph nodeand bone. Two theoretical studies have evaluated the potential risk of vaccine Al in infants, byreference to the oral Minimal Risk Level (MRL) extrapolated from animal studies. Keith et al.,2002 used a too high MRL (2 mg/kg/d), an erroneous model of 100% immediate absorptionof vaccine Al, and did not consider renal and blood-brain barrier immaturity. Mitkus et al.(2011) only considered absorbed Al, with erroneous calculations of absorption duration. Theyignored particulate Al captured by immune cells, which play a role in systemic diffusion andthe neuro-inflammatory potential of the adjuvant. MRL they used was both inappropriate (oralAl vs injected adjuvant) and far too high (1 mg/kg/d) with regard to experimental studiesof Al-induced memory and behavioral changes. Both paucity and serious weaknesses of thesestudies strongly suggest that novel experimental studies of Al adjuvants toxicokinetics shouldbe performed on the long-term, including post-natal and adult exposures, to ensure innocuityand restore population confidence in Al-containing vaccines.; Dans le prolongement de la réflexion menée par l’Académie nationale de pharmacienous avons réévalué les 3 études de référence suggérant l’innocuité des adjuvants alumi-niques. Une seule étude expérimentale a été menée grâce à l’26Al isotopique (Flarend et al.,1997). Cette étude, ignorant la capture cellulaire des adjuvants et menée pendant 28 jours surseulement 2 lapins par adjuvant, a montré une rétention de 78 % de l’Al de l’adjuvant phos-phate de 94 % de l’hydroxyde. Ces résultats sont incompatibles avec une élimination rapidede l’aluminium vaccinal par voie urinaire. L’étude de la distribution tissulaire a omis le muscleinjecté, le ganglion de drainage, et l’os. Deux études théoriques ont calculé le risque de l’Alvaccinal chez le nourrisson, par référence au Minimal Risk Level (MRL) par voie orale extra-polé d’expériences animales. Keith et al. (2002) ont utilisé un MRL trop élevé (2 mg/kg/j), unmodèle erroné d’absorption immédiate de 100 % de l’Al vaccinal, et n’ont pas tenu compte del’immaturité du rein et de la barrière hémato-encéphalique. Mitkus et al. (2011) ne considérantque l’Al absorbé ont ignoré l’Al particulaire dont la capture par les cellules immunitaires joueun rôle dans la migration systémique et le potentiel neuro-inflammatoire de l’adjuvant. Son utilisation d’un MRL par voie orale est inapproprié et d’un niveau (1 mg/kg/j) bien trop élevé auregard des travaux expérimentaux récents. Les durées d’absorption calculées sont inexactes.Ces faiblesses conceptuelles et méthodologiques rendent souhaitable la réalisation de nouvellesétudes toxicocinétiques expérimentales de long terme afin que soit garanti l’innocuité desadjuvants à base d’aluminium.

Allergic asthma and atopic dermatitis are diseases mainly resulting from the activation of Th2 cells, that produce cytokines favouring IgE production and eosinophilia but also of Th1 cells, that contribute to inflammation chronicity. Lymphocyte recruitment and retention of Th cells in target organs are 2 key events for asthma and atopic dermatitis pathogenesis. While lymphocyte migration is regulated by chemokines and lipid mediators such as leukotrienes and prostaglandins, factors involved in lymphocyte retention and survival within inflammatory tissues remain poorly understood. Recent works show that, in allergic diseases, there is an increased expression of fractalkine/CX3CL1 and its unique receptor CX3CR1 and that this chemokine does not act as chemoattractant. In allergic asthma, CX3CR1 expression regulates Th2 and Th1 cell survival in the inflammatory lung, while, in atopic dermatitis, it regulate Th2 and Th1 cell retention into the inflammatory site. Use of peptides blocking fractalkine binding to its receptor is currently tested in the treatment of asthma and atopic dermatitis.

Chlordecone (CLD) is a toxic molecule which (i) contaminates more than 15% of agricultural land in Guadeloupe and Martinique islands, (ii) resists to biotic and abiotic degradation, (iii) accumulates along the food chain and whose the disappearance by soil leaching is estimated at several hundred years. The contamination of livestock in polluted areas is a health, social and economic issue. A literature review on CLD revealed a crying lack of information on its behavior in livestock’s organism and currently, there are less than ten studies which deal with livestock’s decontamination. Two experimental protocols were developed to characterize the behavior of CLD in ruminants’ organism and to evaluate methods that can optimize the decontamination processes of these animals. Results showed that all animals have eliminated more than 70% of Chlordecone in 3 to 4 weeks and neither the initial kids’ body fatness nor the addition of activated carbon or the addition of paraffin oil in the diet during the decontamination period altered these rates of excretion. Following these studies, the lipophilic behavior of CLD in animals is, also, questioned because the results showed that the concentrations of this pollutant, expressed on the fat matter basis, were higher in the liver and the muscles than in the peri-renal fat. These results raised new questions: firstly, on the mechanisms which control the CLD tissue distribution and secondly, on the role of the CLD metabolism and its interaction with the entero-hepatic cycle. The understanding of these processes should help to better adjust the decontamination strategies in order to make them more efficient, La CLD est un composé toxique qui (i) pollue plus de 15% des surfaces agricoles de la Guadeloupe et de la Martinique, (ii) résiste à la dégradation biotique et abiotique, (iii) s’accumule le long de la chaine alimentaire et dont la disparition des sols par lessivage est estimée à plusieurs centaines d’années. Les animaux de rente originaires de ces zones polluées sont contaminés et l’état de l’art a révélé un manque d’information évident sur le comportement de la CLD dans l’organisme de ces animaux et moins de dix publications sur leur décontamination. Deux protocoles expérimentaux ont été conduits sur des caprins mâles en croissance afin de caractériser le comportement de la CLD dans l’organisme des ruminants non lactants et de développer des méthodes optimisant leurs processus de décontamination. Les résultats ont montré que (i) les chevreaux éliminaient plus de 70% de leur CLD tissulaire après 3 à 4 semaines de décontamination et (ii) ni leur état d’engraissement initial ni l’ajout de charbon actif ou d’huile de paraffine dans leur alimentation ne modifiaient ces taux d’excrétion. Ces études ont également montré que la CLD se comportait différemment des autres polluants lipophiles car sa concentration tissulaire (exprimée sur la base de la matière grasse) était plus importante dans le foie et les muscles des animaux contaminés que dans leurs tissus gras. Ces résultats soulèvent des questions sur les mécanismes à l'origine de la distribution tissulaire de la CLD, son métabolisme et sur l’interaction de ce dernier avec le cycle entéro-hépatique. La compréhension de ces processus permettra de mieux ajuster les stratégies de décontamination pour les rendre plus efficaces

In patients with colorectal cancer, nuclear accumulation of p53 is often associated with poor prognosis and resistance to chemotherapy. Overexpression of HER3 is associated with poor prognosis and resistance to therapy targeting EGFR. Our study was performed on 16 samples of colorectal adenocarcinomas. The pieces fixed in formalin were embedded in paraffin. The study of the expression of p53 and HER3 is performed by immunohistochemical technique. Immunohistochemical study of the expression of p53 showed nuclear accumulation of this protein in 87% of colorectal adenocarcinomas analyzed. Regarding the HER3 receptor overexpression was observed in 56% of cases. Overall, 50% of the cases co-expressed p53 and HER3. HER3 and p53 are important markers of colorectal cancer because they provide information about the distinctive biological characteristics of tumors. The prognostic and predictive value of the combination of these two markers could be an important clinical tool.

In recent decades a decrease in sperm quality was observed in most Western countries. While the reasons for this decline are not yet fully understood, environmental factors could greatly contribute. Among them, exposure to materials such as nanomaterials and aluminium, has greatly increased during this period. Therefore, our goal was to assess these exposures impact on male reproductive function. To do so, we conducted two studies to determine testis biodistribution of particles after intramuscular injection in a mouse model. We also conducted two clinical studies, first one to assess the burden of nanoparticles in seminal plasma and to correlate it with sperm count and the second one to evaluate the impact of the aluminum load in semen on sperm parameters. The results of these works and the analysis of literature reassure us about male reproductive toxicity of nanoparticles but revealed a potentially negative impact of aluminum. In both cases, new studies will be needed to further explore these issues, Depuis quelques décennies une diminution de la qualité du sperme a été constatée dans la majorité des pays occidentaux. Si les raisons de cette diminution sont encore incomplètement comprises, des facteurs environnementaux pourraient y contribuer grandement. Parmi eux, l’exposition à certains matériaux, comme les nanomatériaux et l’aluminium, a grandement augmenté durant cette même période. Notre objectif a donc été d’évaluer l’impact de ces expositions sur la fonction de reproduction masculine. Pour ce faire, nous avons réalisé deux études de la biodistribution testiculaire des particules après injection par voie intramusculaire sur un modèle de souris, une étude clinique visant à évaluer la charge du plasma séminal en nanoparticules et à la corréler avec le nombre de spermatozoïdes dans l’éjaculat et une étude clinique visant à évaluer l’impact de la charge spermatique en aluminium sur les paramètres spermatiques. Les résultats de ces travaux couplés à l’analyse de la littérature nous rassurent sur la reprotoxicité masculine des nanoparticules mais montrent l’existence d’un impact potentiellement négatif de l’aluminium. Dans les deux cas, de nouvelles études devront poursuivre l’exploration de ces questions

Depuis la mise en évidence de la Chlordécone (CLD) dans les biotopes antillais en 1999, de nombreux travaux de recherche ont été initiés autour de cette molécule et de son transfert du sol vers les êtres vivants. En 2005, l’AFSSA a présenté des résultats indiquant la présence de la CLD dans la viande de boeuf, de porc, de caprin, de lapin et de poulet. La contamination effective des animaux de rente originaires des zones antillaises polluées pose un problème sur les plans sanitaire, social et économique car la CLD est un composé toxique qui (i) pollue plus de 15 % des surfaces agricoles utiles des îles de la Guadeloupe et de la Martinique, (ii) résiste à la dégradation biotique et abiotique, (iii) s’accumule le long de la chaine alimentaire et dont la disparition des sols par lessivage est estimée à plusieurs centaines d’années. L’apport quotidien de fourrages non contaminés ou le déplacement des animaux vers des zones non polluées font partie des solutions proposées aux éleveurs afin d’interrompre l’exposition de leurs animaux à la CLD et de les décontaminer. Cependant, ces mesures ne sont pas généralisables et les acteurs locaux sont demandeurs de solutions alternatives. L’état de l’art sur la CLD a révélé un manque d’information évident sur le comportement de ce polluant dans l’organisme des animaux d’élevage et moins d’une dizaine de publications traitent de l’élimination de la CLD chez ces animaux. Dans le cadre de cette thèse, deux protocoles expérimentaux ont été conduits sur des caprins mâles en croissance afin de caractériser le comportement de la CLD dans l’organisme des ruminants non lactants et de développer des méthodes optimisant les processus de décontamination de ces animaux. La première expérimentation reposait sur le caractère lipophile de la CLD et elle s’attachait à déterminer si la décontamination des animaux gras était différente de celle des animaux témoins. La seconde expérimentation consistait à empêcher la réabsorption intestinale de la CLD et il s’agissait de déterminer si l’ingestion de charbon actif ou d’huile de paraffine pendant la période de décontamination pouvait interrompre le cycle entéro-hépatique et/ou augmenter la diffusion passive de la CLD chez les chevreaux traités. Les résultats de ces deux études ont montré que (i) les chevreaux en croissance éliminaient plus de 70 % de leur CLD tissulaire après 3 à 4 semaines de décontamination et (ii) ni leur état d’engraissement initial ni l’ajout de charbon actif ou d’huile de paraffine dans leur alimentation ne modifiaient ces taux d’excrétion. Ces études ont, également, montré que la CLD présentait un comportement différent de celui des autres polluants lipophiles car sa concentration tissulaire (exprimée sur la base de la matière grasse) était plus importante dans le foie et les muscles des animaux contaminés que dans leurs tissus adipeux. Ces résultats soulèvent la question des mécanismes à l'origine de la distribution tissulaire de la CLD (taux de perfusion des tissus, affinité relative entre transporteurs sanguins et molécules réceptrices dans les différents tissus) et du rôle du métabolisme de la CLD et de son interaction avec le cycle entéro-hépatique (identification et quantification des différents métabolites, voies d'excrétion respectives). La compréhension de ces processus pourrait permettre de mieux ajuster les stratégies de décontamination pour les rendre plus efficaces. Par ailleurs, le fait que les muscles soient plus concentrés en CLD que les tissus adipeux (comparaison faite sur la base de la matière grasse) soulève également des questions en termes de gestion du risque. En effet, le seuil réglementaire appliqué dans les abattoirs repose sur le niveau de CLD mesuré dans le gras péri-rénal et il convient de se demander si cette valeur est prédictive des niveaux de CLD mesurés dans les muscles ou dans le foie. La corrélation entre les niveaux de CLD mesurés dans les matrices (gras, muscles, foie) est discutée dans ce manuscrit., Since the presence of Chlordecone (CLD) was detected in the French West Indians biotopes in 1999, many research projects have been carried out to better understand its transfer from the soil to living beings. In 2005, the French Agency for Food, Environmental and Occupational Health and Safety (AFSSA) presented results on the presence of CLD in beef, pork, chicken, goat meat and rabbit meat. The effective contamination of livestock in polluted areas is a health, social and economic issue since (i) CLD is a toxic molecule which contaminates more than 15% of agricultural land in Guadeloupe and Martinique islands, (ii) CLD is resistant to biotic and abiotic degradation, (iii) CLD disappearance by soil leaching is estimated at several hundred years and (iv) it accumulates along the food chain. Therefore, the sustainability of breeding which are present in polluted areas and the health of local consumers are challenged by the presence of CLD in animal products. The daily intake of uncontaminated diets or the removal of animals on non-polluted areas are proposed to farmers concerned by this pollution but these possibilities do not apply to all farmers Alternative solutions must be found to decontaminate animals on site. A literature review on CLD revealed a crying lack of information on the behavior of this pollutant in livestock’s organism and currently, there are less than ten studies which deal with the elimination of this pollutant in livestock. As part of this thesis, two experimental protocols were developed to characterize the behavior of CLD in ruminants’ organism and to evaluate methods that can optimize the decontamination processes of these animals. The first experiment was based on the lipophilic nature this pollutant and it sought to determine if decontamination processes were different between control and fatty animals. The second experiment was conducted in order to prevent the intestinal reabsorption of CLD and was aimed to determine whether the incorporation of activated carbon or paraffin oil in feed during the decontamination period could interrupt the reabsorption and/or increase the passive diffusion of CLD in ruminants’ organism. Results showed that all animals have eliminated more than 70 % of Chlordecone in 3 to 4 weeks. No significant differences were observed between treated and control animals in both experiments and neither the initial kids’ body fatness nor the addition of activated carbon or the addition of paraffin oil in the diet during the decontamination period altered these rate of excretion. Following these studies, the lipophilic behavior of CLD in animals is, also, questioned because the results showed that the concentrations of this pollutant, expressed on the fat matter basis, were higher in the liver and the muscles than in the peri-renal fat. These results raised new questions: firstly, on the mechanisms which control the CLD tissue distribution (tissue perfusion rate, relative affinity between blood carriers and receptor molecules in different tissues) and secondly, on the role of the CLD metabolism and its interaction with the enterohepatic cycle (identification and quantification of the different metabolites, respective excretion routes). The understanding of these processes should help to better adjust the decontamination strategies in order to make them more efficient. Furthermore, the fact that muscles were more concentrated in CLD than fat tissues (comparison made on the fat matter basis) also raises questions in terms of risk management. Indeed, the regulatory threshold used, actually, in slaughterhouses is based on the CLD level in peri-renal fat and it is worth asking if these value is predictive of the CLD levels measured in muscles and liver. Thus, the correlation between the levels of CLD measured in these matrices (fat, muscles and liver) is discussed in this manuscript.

The use of nanomaterials drastically increases and yet their behavior in living organisms remains poorly examined. At the same time a better comprehension of the interactions between nanoparticles and the biological environment would allow us to limit potential nanoparticle-based toxicity and fully exploit nanoparticles medical applications. In this perspective, it is high time we develop methods to detect, quantify and follow the evolution of nanoparticles in the complex biological environment, spanning all relevant scales from the nanometer up to the tissue level. In this work we follow the life cycle of magnetic nanoparticles in vivo, focusing on their transformations over time from administration to elimination. As opposed to traditional nano-toxicological approaches, we herein take the nanoparticle perspective and try to establish how biological environment might impact the particles properties and their fate (interaction with proteins, cell confinement, degradation...) from their initial state to a series of changes a nanoparticle might undergo on its journey throughout the organism.

Inhaled drugs are now routinely prescribed in daily medical practice. Recent topics about these treatments have been developed during the fourth annual meeting of the Groupe de travail aérosolthérapie (GAT) of the French-speaking respiratory society (Société de pneumologie de langue française). This article focuses mainly upon the choice of devices, systemic absorption of inhaled drugs and bitter taste receptors in the respiratory tract, a potential new target for drug development.

The primary function of peptide N-glycanase (PNGase) is thought to be the deglycosylation of endoplasmic reticulum associated degradation (ERAD) substrates. However, inhibition of PNGase appears to have little effect upon the destruction rate of many ERAD substrates, and recent data demonstrate deglycosylation-independent functions for PNGase. Whatever the roles of PNGase turn out to be, the identification of a patient presenting with PNGase deficiency will advance our understanding of the importance of this multifunctional protein in human physiology.

The radiopharmaceutical (99m)Tc-DTPA (diethylene-triamine-pentaacetic acid) is a tracer widely used in renal scintigraphy to assess glomerular filtration rate. The estimation of protein binding is very important due to its impact on clinical parameters biodistribution since only the free fraction is filtered by the kidney. A number of laboratory techniques have been developed to study protein binding. Precipitation and ultrafiltration are the mostly used techniques in pharmacology for studies of the binding between proteins and small molecules. The aim of this work is to apply and compare those two analytical methods in (99m)Tc-DTPA protein binding determination in vitro before in vivo application. The results obtained by precipitation with trichloroacetic acid are not enough reproducible, while those obtained by ultrafiltration seem more consistent and reproducible.

Aluminium and indium are two elements used in industrial and medical fields. The purpose of this work was to study the subcellular localization of these elements, after their single and simultaneous oral administration to rats. 2h after the administration of these two elements, the small intestine and the liver were removed.Ultrastructural study showed the presence of electron dense deposits in the lysosomes of apical parts of duodenal enterocytes. When the minerals were administered simultaneously, deposits were observed in lysosomes of duodenal and jejunal enterocytes. No deposits were seen in the hepatic tissue of treated and control rats. Microanalysis identification showed that the deposits are constituted of aluminium, indium as well as phosphorus. Our results suggested that the elements are concentrated, in lysosomes, under the form of insoluble phosphate salts and it seemed that there are no specific lysosomes for the concentration of minerals since the two elements were concentrated in the same lysosome when they are administered simultaneously.

For many years, the intraocular lymphatic system and particularly the drainage of the aqueous humor by this system have been considered non-existant. Our study is the first to demonstrate, in a dynamic in vivo fashion, the existence of lymphatic drainage in the mouse eye. This has become possible with lymphoscintigraphy with nano-molecules of rhenium sulphide, marked by technetium-99m and injected into the anterior chamber of the mouse eye. Readings were taken using an experimental gamma camera specially built for the small animal. The hypothesis of a "uveolymphatic" drainage pathway within the ciliary body, contributing to aqueous outflow, has recently been highlighted by new improvements in microbiology (discovery of lymphatic endothelial-specific markers) and imaging. This new pathway may lead to many prospects: the development of techniques for visualization and quantification of this in vivo lymphatic flow may help to increase our understanding of the physiopathology and perhaps treatment of chronic glaucoma as well as neoplastic conditions.

Clinicians must be aware that aging can lead to changes in the pharmacokinetics and pharmacodynamics of many drugs. Drug distribution may be modified with aging secondarily to the decrease of serum albumin and to modifications of body composition (increase in the proportion of fat mass and decrease of lean mass). Hepatic metabolism of several drugs is reduced with age, especially drugs which depend of hepatic blood flow or P450 cytochroms. The incidence of renal failure increase largely with age. Glomerular filtration rate should be systematically estimated in older patients and, when needed, the doses of those drugs having significant renal elimination should be adjusted. In older patients, changes in the response to drugs can also develop, concerning specially the central nervous system (increased sensibility to any neurological effect of drugs), the cardiovascular system and the renal management of water and electrolytes. In many cases, the pharmacological changes associated to age are mild and requires no dose adjustment. However, many drugs should be adapted depending on the individual situation of each patient, particularly his renal function and nutritional state. Finally, some drugs should be avoided in older patients because of a bad effectiveness/tolerance ratio compared to alternatives.

Due to numerous technical developments, in vivo imaging is suitable for pharmacokinetic and metabolism studies of new chemical entities as well as for evaluating their pharmacological or biological effects. MRI, nuclear medicine, X-Ray, ultrasound and optical imaging are available for both clinical and experimental imaging with even higher performance. For all these imaging modalities, diagnostic agents are useful to improve contrast and specificity. Specific targeting of biological events is addressed by molecular imaging. From a pharmacodynamic perspective, radiolabeling of a new chemical entity allows in vivo visualization quantitative measure of its biodistribution, its elimination and its specific molecular binding. Non-invasive imaging methods are useful for longitudinal investigations of biological changes. Based on nanotechnologies, specificity of drug delivery can be monitored by imaging. New developments in hybrid imaging technologies as well as multimodal contrast agents reinforce in vivo experimental and clinical proof of mechanism of new chemical entities.

Arsines family includes many compounds with various toxicities. Arsenic trihydride or arsine is the most toxic form of arsenic. Powerful haemolytic gas, it has never been used as a chemical weapon because its toxicity is not immediate and it is non persistent. However, cases of industrial poisoning with arsine are still identified in spite of a strict regulation at work. It is also identified as a potential toxic of chemical terrorism. This agent, of which the mechanism of action is still not well defined, is badly recognized because of intoxications rarity. However, fast detection means are available. Health professionals and especially those who are involved in piratox plan need to learn to recognize arsine intoxication (hematuria, oliguria, haemolytic anemia) in order to provide early, specific treatment and avoid damages.

The human Fc portion of humanized monoclonal antibodies (mAb) gives them a half-life of around 21 days, similar to that of endogenous immunoglobulin G (IgG). Neonatal Fc receptor (FcRn) plays a major role in the pharmacokinetics (PK) of mAbs. By protecting them from degradation, it is responsible for their long half-life and by allowing their transcytosis, it influences their absorption and their distribution. After subcutaneous administration, the absorption of mAbs is slow and incomplete. Most of them are still administered intravenously. Their distribution in tissues is poorly known. It seems limited and certain organs, such as the central nervous system, may be protected by FcRn. The elimination of mAbs is partly mediated by binding to their target-antigen, a mechanism that leads to dose-dependent PK. The interindividual variability in mAb PK is clinically relevant and its main known origins are demographic factors, antigen mass and immunization. Complex PK models are needed to describe satisfactorily their fate in the body and their concentration-effect relationship.

The first treatment ever by radio-immunotherapy (RIT) was performed by William H. Beierwaltes in 1951 and was a success. Fifty years later, the main question is to find ways of extending the success of radiolabelled anti-CD20 antibodies in indolent non-Hodgkin's lymphoma to other forms of cancer. Solid tumours are much more radioresistant than lymphomas, but they respond to RIT if the lesions are small. Clinical situations of residual or minimal disease are thus the most likely to benefit from RIT in the adjuvant or consolidation settings. For disseminated disease, like leukemias or myelomas, the problem is different: beta- particles emitted by the radioactive atoms classically used for cancer treatment (iodine-131 or yttrium-90) disperse their energy in large volumes (ranges 1 mm to 1 cm) and are not very effective against isolated cells. Advances in RIT progress in two directions. One is the development of pretargeting strategies in which the antibody is not labelled but used to provide binding sites to small molecular weight radioactivity vectors (biotin, haptens). These techniques have been shown to increase tumour to non-target uptake ratios and anti-tumour efficacy has been demonstrated in the clinic. The other approach is the use of radionuclides adapted to the various clinical situations. Lutetium-177 or copper-67, because of the lower energy of their emission, their relatively long half-life and good gamma emission, may significantly improve RIT efficacy and acceptability. Beyond that, radionuclides emitting particles such as alpha particles or Auger electrons, much more efficient to kill isolated tumour cells, are being tested for RIT in the clinic. Finally, RIT should be integrated with other cancer treatment approaches in multimodality protocols. Thus RIT, now a mature technology, should enter a phase of well designed and focused clinical developments that may be expected to afford significant therapeutic advances.

The in vitro assessment of the aerosol fine particle 'respirable' fraction and the aerodynamic particle size distribution on cascade impactors is necessary to meet the demands of regulatory authorities but does not predict lung deposition of an inhaled drug notably in patients with chronic obstructive airway diseases. Total drug delivery to the lung can be assessed using pharmacokinetic methods. Pharmacokinetic studies are easier to conduct in patients with chronic obstructive diseases than imaging studies using two- or three-dimensional scintigraphic methods. For fast acting inhaled drugs, such as bronchodilators, the relationship between lung deposition and clinical efficacy can be established by modeling of the pharmacokinetic - pharmacodynamic (bronchodilation) relationship. Improvement of lung deposition is usually associated with a reduction of the dose required for clinical efficacy but the change in the dose-response relationship is not proportionally related to the increase in lung deposition. Aerosols delivering small particles improve lung deposition, by distributing drug diffusely throughout the lungs, in particular by reaching peripheral airways. These aerosols do not improve clinical efficacy as evaluated on classical spirometric or clinical criteria but often permit a reduction in dosage. Also, they can minimize oropharyngeal deposition, reduce variability in lung deposition and spirometric response related to change in inspiratory flows.

Apelin is a recently identified peptide which plays an important role in cardiovascular function and in water metabolism. Apelin and its receptor APJ (apelin system) are involved in zebra fish and xenopus cardiovascular development. Apelin is a pro-angiogenic factor. Apelin is a potent cardiac inotropic agent and exerts a vasodilatory effect in arterial and venous territories. Apelin decreases vasopressin production and its plasma level is conversely related to plasma vasopressin. Several effects of the apelin system counteract those of the renin angiotensin system. It may represent a new and promising therapeutic opportunity for the treatment of cardiovascular diseases.

Uranium is a radionuclide present in the environment since the origin of the Earth. In addition to natural uranium, recent deposits from industrial or military activities are acknowledged. Uranium's toxicity is due to a combination of its chemical (heavy metal) and radiological properties (emission of ionizing radiations). Acute toxicity induces an important weight loss and signs of renal and cerebral impairment. Alterations of bone growth, modifications of the reproductive system and carcinogenic effects are also often seen. On the contrary, the biological effects of a chronic exposure to low doses are unwell known. However, results from different recent studies suggest that a chronic contamination with low levels of uranium induces subtle but significant levels. Indeed, an internal contamination of rats for several weeks leads to detection of uranium in many cerebral structures, in association with an alteration of short-term memory and an increase of anxiety level. Biological effects of uranium on the metabolisms of xenobiotics, steroid hormones and vitamin D were described in the liver, testis and kidneys. These recent scientific data suggest that uranium could participate to increase of health risks linked to environmental pollution.

Uranium is a radionuclide present in the environment since the origin of the Earth. In addition to natural uranium, recent deposits from industrial or military activities are acknowledged. Uranium's toxicity is due to a combination of its chemical (heavy metal) and radiological properties (emission of ionizing radiations). Acute toxicity induces an important weight loss and signs of renal and cerebral impairment. Alterations of bone growth, modifications of the reproductive system and carcinogenic effects are also often seen. On the contrary, the biological effects of a chronic exposure to low doses are unwell known. However, results from different recent studies suggest that a chronic contamination with low levels of uranium induces subtle but significant levels. Indeed, an internal contamination of rats for several weeks leads to detection of uranium in many cerebral structures, in association with an alteration of short-term memory and an increase of anxiety level. Biological effects of uranium on the metabolisms of xenobiotics, steroid hormones and vitamin D were described in the liver, testis and kidneys. These recent scientific data suggest that uranium could participate to increase of health risks linked to environmental pollution.; L’uranium est un radionucléide présent dans l’environnement depuis l’origine de la terre. A cet uranium d’origine naturelle viennent s’ajouter des apports plus récents résultant des activités industrielles et militaires de l’homme. La toxicité de l’uranium résulterait d’une combinaison de ses propriétés chimiques (métal lourd) et radiologiques (émission de rayonnements ionisants). La toxicité aiguë se manifeste chez l’animal par une importante perte de poids et des signes d’atteinte rénale et cérébrale. Une altération de la formation osseuse, une modification du système reproducteur et des effets carcinogènes sont également couramment observés. A contrario, les effets biologiques d’une exposition chronique à de faibles doses sont peu connus. Cependant, les résultats de différentes études récentes suggèrent que la contamination chronique à faible niveau par l’uranium induirait des effets biologiques subtils mais significatifs dans des organes qui ne sont pas connus pour être des organes sensibles à la contamination par l’uranium. C’est le cas du système nerveux central par exemple puisque, récemment, ont été montrées une altération de la mémoire à court terme et une augmentation du niveau d’anxiété, associées à la présence d’uranium dans différentes structures cérébrales chez l’animal (essentiellement rongeur). La grande nouveauté dans la connaissance des effets d’une contamination chronique par l’uranium est la mise en évidence d’effets biologiques de l’uranium sur plusieurs métabolismes majeurs de l’organisme, incluant le métabolisme des médicaments, des hormones stéroïdiennes, de la vitamine D et du fer. Ces données scientifiques récentes suggèrent que l’uranium pourrait participer à l’augmentation des risques sanitaires liés à la pollution de l’environnement.

Radioimmunotherapy (RIT) is an emerging treatment option for non-Hodgkin's lymphoma. Only Zevalin (Bayer Schering Pharma) radiolabeled with yttrium 90 ((90)Y) is approved in France for the treatment of adult patients with rituximab relapsed or refractory CD20+ follicular B-cell non-Hodgkin's lymphoma. This radioimmunotherapeutic agent consists of ibritumomab, a murine anti-CD20 monoclonal antibody, conjugated to the metal chelator tiuxetan for retention of the beta emitter (90)Y. This review presents the concept of RIT. The pharmacological characteristics of [(90)Y]-ibritumomab tiuxetan, the specificity of its preparation and its special precautions for use will be described. The other radionuclides and antibodies in development will also be mentioned.

Photodynamic therapy consists in destroying a tumoral or a non tumoral tissue by the effect of both a photosensitizing molecule and a laser light. This simple concept has needed numerous years in order to be used in routine treatments with both photosensitizers and laser light delivered optimally. Researches in chemistry lead to new porphyrin and bacteriochlorophyl derivatives which alleviate the decrease of light absorption by endogenous molecules and in consequence allow a deeper light penetration. Short half-life of these compounds allows an easier treatment monitoring. In parallel, improvements in both laser technology and fibers allow new indications in various pathologies. First applications took place in treatment of respiratory, digestive and urologic cancers. The biggest success to date is recorded in ophthalmology with the treatment of age related macular degeneration. New approaches are explored and clinical studies are ongoing.

Delta-9-tetrahydrocannabinol (Delta-9-THC) is the main psychoactive ingredient of cannabis. Smoking is currently most common use of cannabis. The present review focuses on the pharmacokinetics of THC. The variability of THC in plant material which has significantly increased in recent years leads to variability in tissue THC levels from smoking, which is, in itself, a highly individual process. This variability of THC content has an important impact on drug pharmacokinetics and pharmacology. After smoking THC bioavailability averages 30%. With a 3.55% THC cigarette, a peak plasma level near 160 ng/mL occurs approximately 10 min after inhalation. THC is eliminated quickly from plasma in a multiphasic manner and is widely distributed to tissues, which is responsible for its pharmacologic effects. Body fat then serves as a long-term storage site. This particular pharmacokinetics explains the noncorrelation between THC blood level and clinical effects as is observed for ethanol. A major active 11-hydroxy metabolite is formed after both inhalation and oral dosing (20 and 100% of parent, respectively). The elimination of THC and its many metabolites, mainly THC-COOH, occurs via the feces and urine for several weeks. Thus, to confirm abstinence, urine THC-COOH analysis would be a useful tool. A positive result could be checked by gas chromatography-mass spectrometry THC blood analysis, indicative of a recent cannabis exposure.

Decisive analytical progress for biological cannabis testing has been achieved over the past ten years. These major contributions allow to accurately identify and quantify in detail the substances present in the body following cannabinoid exposure. Fast and reliable onsite urine testing is used to implement the French law on narcotic drugs and its relationship to motorway safety. A positive test result will indicate a very recent exposure which is detectable up to five days following intake. Then a clinical examination and blood collection are performed by a physician, with a subsequent blood tetrahydrocannabinol (THC) analysis by authorized professionals registered at the judicial court of appeal. A result higher than the cut-off value is associated with a very recent cannabis exposure. Blood, urine, saliva and sweat cannabis determination are assessed according to the most recent pharmacokinetic and analytical data.

Numéro national de thèse : 2005CLF1PP04 Diplôme : Dr. d'Universite

Medical and biological imaging has undergone a revolution in the past decade. Positron emission tomography (PET) has been developed to visualize biochemical and physiological phenomena in living humans and animals. For instance, blood flow, blood volume, glucose metabolism, amino acid metabolism, can be quantitatively estimated by means of PET with various radioactive tracers. This functional and molecular imaging technique has progressed rapidly from being a research technique in laboratories to a routine clinical imaging modality. The most widely used radiotracer in routine is 18F-fluorodeoxyglucose (18FDG), which is an analogue of glucose. Since glucose metabolism is increased many fold in malignant tumors, PET has a major role in the field of clinical oncology and recently in cardiology and neurology. PET is also a valuable tool to study cerebral or cardiac binding sites and to image the expression of reporter genes in small animals. In this review, we summarize the most recent developments in PET imaging with particular reference to the radiotracers available and their application.

Voriconazole is a fluoropyrimidine derivative of fluconazole with an extended spectrum of activity, non-linear pharmacokinetic characteristics, available intravenously and orally with an excellent bioavailability, and a good penetration into tissues including the brain. It is metabolized in the liver by the cytochrome P450 and less than 1% is eliminated in the urine. Voriconazole has been studied extensively in numerous randomized clinical trials of invasive fungal infections and became the therapy of choice of invasive aspergillosis, fusariosis and scedosporiosis. Voriconazole is an alternative for invasive candidiasis refractory or resistant to fluconazole. Voriconazole has a good tolerability and acceptable safety profile and has added a new weapon to our therapeutic armamentarium against fungi.

Among the agents used to produce pleural symphysis talc is the most effective and least expensive. However, its use is controversial on account of the description of respiratory complications associated with subsequent systemic spread of the talc particles. This hypothesis rests on clinical and experimental observations of talc particles in the viscera. However, all talc preparations are not identical and this extra-pleural spread could be dependent on particle size. This experimental study was undertaken to determine whether there was systemic spread of a calibrated talc preparation used routinely in clinical practice following intra-pleural administration in rats.48 rats received 20 mg (11 rats) and 40 mg (33 rats) of calibrated talc suspended in 1 ml of physiological saline by intra-pleural injection. The animals were randomised for sacrifice at 24 hours (22 rats) and 72 hours (22 rats) after the injection. The lungs, parietal pleura, diaphragm, liver, spleen, pericardium, brain and blood were examined by light microscopy and polarised light to search for bi-refringent particles.No deaths occurred during the procedure. At the time of sacrifice no pleural symphysis was seen. In 5 animals some talc particles were seen in the extra-thoracic organs: in the liver in 3 in the spleen in 1 and one particle in the brain of one animal examined by electron microscopy. No talc particles were found in the blood.Intra-pleural injection of calibrated talc, (Steritalc-Novatech-Plan de Grasse-France) has a weak systemic spread insmall animals. These results may be related to the diameter of the talc particles used (mean 33.6 microns; median 31.3 microns). The hypothesis that systemic spread is influenced by the diameter of the talc particles needs to be supported by experimental studies using talc particles of smaller diameter in order to compare the systemic distribution of the different preparations.

Controlling release of a trace is an indispensable pharmacological technique. Release of the active substance can be modulated to meet the desired kinetic requirements of the formulation by carefully choosing the excipient and controlling the solubility of the tracer. We studied the preformulation of a semi-solid matrix, Gelucire, to examine the kinetic properties of theophylline release. Several models were analyzed. The results show that the formulation must be specific for the semi-solid matrix used.

The goal of the present review is to collect information concerning membrane effects induced by lindane intoxication, a y isomer of hexachiorocyclohexane (gamma-HCH) that has been largely used as an insecticide and disinfectant in agriculture and entered also in the composition of some lotions, creams and shampoos used against parasites (lice and scabies). Absorbed through respiratory, digestive or transcutaneous pathways, lindane accumulates within lipid rich tissues. Lindane accumulation depends on the duration of the exposure and affects tissues in the following order: adipose tissuesbrainkidneymusclelungsheartliverblood. Whatever the mode of lindane absorption, it accumulates in blood and is distributed throughout the body. It may affect human health by exerting systemic, immunologic, teratogenic, and/or cancerogenic effects. The symptoms of lindane intoxication are different according to the mode of intoxication, acute or chronic. The absorption of high doses of gamma-HCH is particularly toxic for the central nervous system and for the female and male reproduction apparatus in mammals where lindane is considered as an endocrine disruptor. Lindane is highly lipophilic and incorporates into biological membranes according to the following sequence: mitochondriasarcoplasmic reticulummyelinbrain microsomeserythrocytes. Lindane exerts a stimulating action on synaptic transmission and inhibits the chloride current activated by gamma-amino butyric acid (GABA) of many muscular and nervous preparations by interacting with the receptors GABA-chloride channel complex. It seems to affect calcium homeostasis of many tissues. The similarity between lindane and inositol (1, 4, 5) phosphate (IP3) suggested that lindane releases Ca2+ from IP3-sensitive intracellular stores in macrophages and myometrial cells. Ca2+ release from reticulum endoplasmic, mitochondria and other Ca2+ stores has been reported in cat kidney cells. Lindane altered energetic metabolism of hepatic mitochondria and the inositol-phosphate synthesis in neuronal cells. However, lindane does not compete with the IP3 receptor. Lindane produces a Ca2+ influx in mice peritoneal macrophage cells responsible for the Ca2+ induced Ca2+ release produced by phospholipase C via IP3 pathway and resulting in a maintained increase of the free cytosolic Ca2+ concentration. Lindane decreased the membrane erythrocyte and cerebral cell concentration of phosphatidyl inositol PI, PIP and PIP2 in rats repetitively exposed to lindane for 3 or 6 months. Lindane induces oxidative stress; it modifies the activity of the scavenger enzymes. This effect is involved in the inhibition of intercellular gap junctions. Modifications of the electrocardiogram (ECG), sinusal rhythm alteration and negative and dysphasic variations of T wave, similar to those produced by hyperkaliemia, have been reported after lindane absorption. During acute lindane poisoning, the activities of serum transaminases (SGOT, SGTP), and lactate deshydrogenase (LDH) increase. Lindane produces histological alterations of cardiac tissues and a cardio-vascular dystrophy (contracture, degenerescence and necrosis) mainly in the left ventricular wall and a hypertrophy of the left ventricle. Chronic application of residual doses of lindane shortened the action potential duration in rat papillary muscle. These effects were similar to those induced by hyperthyroidism. Lindane increases the triiodothyronine (T3) serum level in hyperthyroid rats. T3 plays an important role in the postnatal development of the rat ventricle by increasing the density of potassium channels which contribute to action potential shortening during the development. Thyroid hormones influence the regulation and the expression of messengers ARN which encode different potassium channels involved in action potential repolarization (Kvl.2; Kvl.4; Kvl.5; Kv2.1; Kv4; HCN2). The thyrotropine-releasing hormone (TRH) modulates the HERG-type rapid delayed potassium channel (IKr) encoded by the human gene ether-a-go-go in rat anterior pituitary cells GH3/B6. This channel is involved in the cardiac long QT syndrome. TRH modifies the current kinetics of human HERG potassium channel co-expressed in Xenopus oocytes with the TRH receptor, whose activity is modulated via the protein kinase C pathway linked to a G protein-coupled receptor and is regulated by changes in the PIP2 concentration in the membrane. IKr channels regulation is also dependent on sexual hormones. In conclusion, lindane affects the excitable membranes and the cardio circulatory system. These alterations (may) represent a potential risk for human health.

The present paper bears on the main effects of lindane (gamma isomer of hexachlorocyclohexane) on endocrine and reproductive functions in mammals. This pesticide, once widely used to kill lice and a variety of pests that attack agricultural products, livestock and trees, has been progressively eliminated from many applications since the mid-1970s in Europe or USA, but is still used in the rest of the world. Lindane is absorbed through respiratory, digestive or cutaneous routes and accumulates in fat tissues. It damages human liver, kidney, neural and immune systems and induces birth defects, cancer and death. Chronic administration results in endocrine disruption in birds as well as in mammals. Treatment with 1-40 mg of lindane/kg b.w. disrupts testicular morphology, decreases spermatogenesis, inhibits testicular steroidogenesis, reduces plasma androgen concentrations and may adversely affect reproductive performances in males. In females, lindane disrupts the estrous cycle, reduces serum estrogen and progesterone levels, decreases sexual receptivity whereas in pregnant dams it decreases whelping rate and litter size. These effects were also observed in some rats exposed to residual environmental doses. In addition, there is concern that irreversible effects may be induced when animals are exposed to endocrine disrupting chemicals during critically susceptible phases of sexual differentiation or development. These effects would results from (i) alterations of gonade or gamete cell membranes (ii) cell metabolism changes including alterations of ionic exchanges (mainly calcium or potassium), direct or free radical-mediated inhibition of steroidogenesis (iii) or neuroendocrine changes leading to a decrease in sexual performance of either parents or their offsprings exposed in utero or through lactation.

Many pathologies are associated with abnormalities of glucose metabolism or with perturbations of its transport (type 2 diabetes or insulin-resistance). The pre-diabetic state is characterised by a state of insulin-resistance, in others words a defect of glucose transport in insulin-sensible tissues, such as muscles and adipose tissues. The mathematical modelling of experimental data can be an excellent method to explore the mechanisms implied in the studied biological phenomenon. Thus, starting from a symbolic formulation like the compartmental modelling, it can be possible to develop a theoretical basis for the observation and to consider the best-adapted experiments for the study. We showed with mathematical models that [123I]-6-deoxy-6-iodo-D-glucose (6-DIG), shown as a tracer of glucose transport in vitro, could point out this transport abnormality. To quantify the insulin resistance, we estimated the fractional transfer coefficients of 6-DIG from the blood to the organs. We realised many studies to lead to a satisfying model; special attention has been paid to the precision of the parameter to select the best model. The results showed that by associating experimental data obtained with 6-DIG activities and an adapted mathematical model, discriminating parameters (in and out fractional transfer coefficients) between the two groups (control and insulin-resistant rats) could be pointed out.

Physiological changes that occur in the aging process may directly affect drug pharmacokinetics. In the absence of disease or other pathologic conditions, age-related changes in pharmacokinetics principally affect drug absorption, distribution, metabolism or elimination. One factor that does change consistently with age is renal clearance, consequently a common pharmacokinetic change is reduced drug clearance, especially for drugs excreted largely unchanged by the kidneys. Alteration of the pharmacokinetics of drugs in the elderly may necessitate adjustment of dosages to prevent toxicity or inadequate therapy. As a broad generalization, dosage should be reduced in elderly patients, reflecting the general decline in body function with age.