Princípios de terapêutica antibiótica na doença crítica

RESUMO: A infeção é frequente durante a doença crítica, quer como causa da doença crítica quer como complicação da sua evolução. Paradoxalmente, os avanços da medicina moderna aumentaram eles próprios o risco de infeção, ao permitir a sobrevida até idades avançadas, ao criar um novo grupo de doentes imunodeprimidos, nomeadamente doentes tratados com fármacos que interferem com as suas defesas naturais (corticóides, citostáticos), ao aumentar o tempo de vida de hospedeiros com comorbilidades debilitantes. Os antibióticos são um dos elos essenciais no tratamento da infeção. Contudo o seu uso também promove a seleção e crescimento de bactérias resistentes. Para além disso as doses convencionais de antibióticos foram selecionadas numa altura em que a resistência era um fenómeno raro e podem não ser atualmente as mais adequadas. Existe hoje muita evidência acumulada que os doentes críticos sofrem alterações da sua farmacocinética (PK) que podem facilitar a ocorrência de falência terapêutica ou de toxicidade tanto por sub como por sobredosagem de antibióticos. Essas alterações são complexas e difíceis de estudar. Finalmente, também a farmacodinâmica (PD) dos antibióticos pode estar alterada nesta população, podendo haver necessidade de ajustar os alvos terapêuticos de forma individual. O objetivo deste trabalho foi investigar a relação entre a terapêutica antibiótica, as suas características PK e PD, a carga bacteriana e o prognóstico dos doentes críticos. O plano de investigação incluiu: 1. Dados da epidemiologia portuguesa de doentes críticos com infeção; 2. Avaliação da relação entre a carga bacteriana, o tempo até ao início do tratamento antibiótico e o prognóstico dos doentes críticos; 3. Avaliação da evolução da PK durante o tratamento da infeção; 4. Um estudo multicêntrico para avaliação da eficácia da terapêutica com um β- lactâmico doseado de acordo com a relação PK/PD. Na introdução é descrita a importância dos antibióticos, a sua origem e o problema crescente das resistências bacterianas relacionadas com o seu emprego e abuso. É salientada a importância de racionalizar a posologia, de acordo com os conceitos de PK e de PD. No Capítulo 1 são apresentados dados de epidemiologia portuguesa de infeção em doentes críticos, sobretudo retirados de dois estudos prospetivos, observacionais, os quais incluíram mais de 50% da capacidade de internamento em cuidados intensivos existente em Portugal. No Capítulo 2 são descritos os conceitos de PK e as suas alterações nos doentes críticos. De seguida são revistos os conceitos de PD de antibióticos e a sua aplicação a esta população, em particular durante as infeções graves (Capítulo 3). Nos capítulos seguintes são aprofundadas estas alterações da PK nos doentes críticos e as suas causas, de forma a destacar a importância da monitorização da concentração dos antibióticos. São apresentados os dados duma revisão sistemática de PK de antibóticos nesta população (Capítulo 4), pormenorizadas as alterações da PD que comprometem a eficácia da terapêutica antibiótica, facilitam o desenvolvimento de resistências e podem levar a falência terapêutica (Capítulo 5). Consequentemente a compreensão global destas alterações, da sua relevância clínica e a revisão da evidência disponível facilitou o desenvolvimento do próprio plano global de investigação (Capítulos 6 e 7). No Capítulo 6.1 são descritos os antibióticos tempo-dependente e a importância de aumentar o seu tempo de perfusão. Foi desenhado um estudo multicêntrico para comparar a eficácia e segurança da perfusão contínua da piperacilina tazobactam (um antibiótico β-lactâmico associado a um inibidor de β-lactamases) com a mesma dose do antibiótico, administrado em dose convencional, intermitente. A importância de dosear corretamente os antibióticos concentração-dependente foi também avaliada num estudo a primeira dose dos aminoglicosídeos (Capítulo 6.2). Outras estratégias para melhorar os resultados assistenciais dos doentes infetados são abordadas no Capítulo 7, em particular a importância da terapêutica antibiótica precoce, a avaliação da carga bacteriana e a compreensão da variação da PK ao longo do tratamento da infeção. Foi desenvolvido um algoritmo de abordagem terapêutica que incluiu estas alterações da PK e da PD nos doentes críticos. Finalmente no Capítulo 8 são descritos mecanismos de desenvolvimento das resistências bacterianas bem como estratégias para a sua abordagem. O Capítulo final (Capítulo 9) aponta um plano para futuras áreas de trabalho. O elemento chave identificado neste trabalho de investigação é o reconhecimento da variabilidade significativa da PK dos antibióticos durante a doença crítica, a qual condiciona a sua posologia. Estas alterações estão relacionadas com a própria gravidade da doença e tendem a diminuir ao longo do seu tratamento. No entanto nem a gravidade da doença nem as características individuais as permitem prever de forma aceitável pelo que a utilização duma posologia universal, independente da situação clínica concreta, pode ser inadequada. As estratégias para melhorar os resultados assistenciais dos doentes críticos infetados devem ser baseadas na individualização da posologia antibiótica de acordo com os princípios da PK e da PD, preferencialmente apoiadas em doseamentos da sua concentração. ------------------------------------ ABSTRACT: Infection commonly occurred during critical illness, either as a cause or complicating the course of the disease. Advances in medicine had paradoxically increase the risk of infection, both by improving survival to older ages and by introducing a new group of immunosuppressed patients, those who are treated with drugs that interfere with their natural defenses (corticosteroids, cytostatics) and those who survived longer with aggressive diseases. Antibiotics are of paramount importance for treating infection. However the use of these drugs also promote the selection and growth of resistant bacteria. Furthermore conventional antibiotic doses were calculated for less severe patients during a time when resistance was rare. Nowadays there is increasing evidence that critically ill patients experiment altered pharmacokinetics (PK) that may lead to therapeutic failure and/or drug toxicity. Equally, such PK alterations are complex and challenging to investigate. Finally pharmacodynamics (PD) may also be different in this population and antibiotic targets may need to be tailored to the individual patient. The aim of this research was to investigate the relationship between antibiotic therapy, its PK and PD, bacterial burden and critically ill patients outcomes. The research plan comprised of: 1. Epidemiological portuguese data of critically ill infected patients; 2. Relationship between burden of bacteria, time until the start of antibiotics and patient outcomes; 3. Evaluation of PK during treatment of infection; 4. A multicentre study evaluating PK guided β-lactam therapy. The introductory chapter outlines the importance of antibiotics, its origins, the problem of increasing bacteria resistance, related to its use and overuse and the importance of rational drug dosing using PK and PD concepts. In Chapter 1 portuguese epidemiological data of infections in critically ill patients is presented, mostly coming from two prospective observational studies, encompassing more than 50% of critically ill beds available in Portugal. Chapter 2 describes the concepts of PK and the changes occurring in critically ill patients. This is followed by a review of the concepts of PD of antibiotics and its application to this population, especially during severe infections (Chapter 3). In the following chapter these changes in antibiotics PK in critical illness are and its causes are detailed, to outline the importance of therapeutic drug monitoring. Data on a systematic review of antibiotics PK in those patients is provided (Chapter 4). The following chapter (Chapter 5) elucidates important changes in PD, that compromises antibiotic therapy, facilitate the occurrence of resistance and may lead to therapeutic failure. Thus, an understanding of the clinical problem and available evidence facilitated the development of a comprehensive research plan (Chapter 6 and Chapter 7). Chapter 6.1 describes time-dependent antibiotics and the importance of extending its perfusion time. A multicenter study was designed to compare the continuous infusion of piperacillin tazobactam (a β-lactam antibiotic) with the same daily dose, prescribed in a conventional, intermittent dose. The importance of correct dosing of antibiotics was also assessed through a study addressing aminoglycoside (a concentration-dependent antibiotic) therapy (Chapter 6.2), focusing on its first dose. Strategies to improve severe infected patients outcomes were addressed in Chapter 7, namely the importance of early antibiotic therapy, assessing the burden of bacteria and understanding changes in antibiotic concentration during the course of infection. An algorithm to include all the described changes in both PK and PD of critically ill patients was developed. Finally in Chapter 8 mechanisms of the increasing resistance of bacteria are described and strategies to address that problem are proposed. The closing chapter (Chapter 9) lays a roadmap for future work. The key finding of this research is the significant variability of the antibiotics PK during critical illness, which makes dosing a challenging issue. These changes are related to the severity of the infection itself and improve through the course of the disease. However neither disease severity nor individual characteristics are useful to predict PK changes. Therefore, the use of a universal dose approach, regardless of the individual patient, may not be the best approach. Strategies to improve patients’ outcomes should be based on tailoring antibiotics to the individual patient, according to PK and PD principles, preferentially supported by therapeutic drug monitoring.

mRNA metabolism: nonsense mediated mRNA decay as a tool for gene therapy and the role of human DIS3L2 in transcript degradation

Tese de mestrado em Biologia Humana e Ambiente, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2015

Adjuvant early breast cancer systemic therapies according to daily used technologies.

Prognosis of early breast cancer patients is significantly improved with the use of adjuvant therapies. Various guidelines have been proposed to select patients who will derive the most benefit from such treatments. However, classifications have limited usefulness in subsets of patients such as those with node negative breast cancer. The 2007 St. Paul de Vence Clinical Practice Recommendations proposed to consider adjuvant therapy in accordance with the 10-year relapse-free survival reduction estimated by Adjuvant! Online. However, many limitations remain regarding the use of Adjuvant! Online. Among them, adverse prognostic and/or predictive factors such as vascular invasion, mitotic activity, progesterone receptor negativity, and HER-2 expression are not incorporated in the routine clinical decision process. Our group has therefore issued guidelines based on the consideration of both Adjuvant! Online calculations and the prognostic and/or predictive effects of these markers. In addition, web-accessible comprehensive tables summarizing these recommendations are provided.

Felodipine-metoprolol combination tablet: a valuable option to initiate antihypertensive therapy?

The aim of the present study was to assess the efficacy and tolerability of a calcium antagonist/beta-blocker fixed combination tablet used as first-line antihypertesnive therapy in comparison with an angiotensin converting enzyme inhibitor and placebo. Patients with uncomplicated essential hypertension (diastolic blood pressure between 95 and 110 mm Hg at the end of a 4-week run-in period) were randomly allocated to a double-blind, 12-week treatment with either a combination tablet of felodipine and metoprolol (Logimax), 5/50 mg daily (n = 321), enalapril, 10 mg daily (n = 321), or placebo (n = 304), with the possibility of doubling the dose after 4 or 8 weeks of treatment if needed (diastolic blood pressure remaining >90 mm Hg). The combined felodipine-metoprolol treatment controlled blood pressure (diastolic < or =90 mm Hg 24 h after dose) in 72% of patients after 12 weeks, as compared with 49% for enalapril and 30% for placebo. A dose adjustment was required in 38% of patients receiving the combination, in 63% of patients allocated to placebo, and 61% of enalapril-treated patients. The overall incidence of adverse events was 54.5% during felodipine-metoprolol treatment; the corresponding values for enalapril and placebo were 51.7% and 47.4%, respectively. Withdrawal of treatment due to adverse events occurred in 18 patients treated with the combination, in 10 patients on enalapril, and 12 patients on placebo. No significant change in patients' well-being was observed in either of the three study groups. These results show that a fixed combination tablet of felodipine and metoprolol allows to normalize blood pressure in a substantially larger fraction of patients than enalapril given alone. This improved efficacy is obtained without impairing the tolerability. The fixed-dose combination of felodipine and metoprolol, therefore, may become a valuable option to initiate antihypertensive treatment.

Viability of Ascaris lumbricoides eggs eliminated after anti-helminthic therapy

The viability of Ascaris lumbricoides eggs passed in the feces was evaluated after treatment of patients with one of the anti-helminthic drugs (thiabendazole, levamisole, cambendazole, pyrantel pamoate, mebendazole or praziquantel). For each drug, a group of 5 children was selected and their feces collected 24 h before treatment and 24, 48 and 72 h after drug administration, except for mebendazole, with the feces being collected throughout the period of treatment. After sedimentation, the total amount of eggs from each collection was transferred to tissue culture flasks containing 10 ml H2So4 O, 1N, with the addtion of 3 drops of a miconazol solution, and incubated at 28 graus centígrados, individually, for 80 days. The flasks wee maintained open and the culture were oxigenated daily by manual agitation. On the 80th day of culture, 20-days-old albino mice were inoculated with 3,200 embryonated eggs, per os. Larvae were recovered from their lungs and hearts, on the 8th day after infection, according to Baerman's method (Morais, 1948). Thiabendazole showed 100.0% ovicidal capacity as early as 48 after treatment. Inhibition of embrionary development was observed when thiabendazole was used. This drug also had an effect on the eggs infectivity when inoculated into normal mice. No significant effect on embrionary development was observed for the other drugs tested.

Canakinumab Reduces The Risk Of Acute Gouty Arthritis Flares During Initiation Of Allopurinol Therapy: Results Of A Double-blind, Randomised Study

RATIONALE: This study assessed the efficacy and safety of canakinumab, a fully human anti-interleukin-1beta monoclonal antibody, for prophylaxis against acute gouty arthritis flares in patients initiating uratelowering therapy.METHODS: In this double-blind, double-dummy, dose-ranging study, 432 patients with gouty arthritis initiating allopurinol therapy were randomised 1:1:1:1:1:1:2 to receive: a single dose of canakinumab, 25, 50, 100, 200, or 300 mg subcutaneously (sc); four 4-weekly doses of canakinumab (50150125125 mg sc); or daily colchicine 0.5 mg orally for 16 weeks. Patients recorded details of flares in diaries. The study aimed to determine the canakinumab dose having equivalent efficacy to colchicine 0.5 mg at 16 weeks.RESULTS: A dose-response for canakinumab was not apparent with any of the four pre-defined dose-responsemodels. The estimated canakinumab dose with equivalent efficacy to colchicinewas belowthe range of doses tested.At 16 weeks, therewas a 62-72% reduction in themean number of flares per patient for canakinumab doses >50 mg vs colchicine based on a negative binomial model (rate ratio: 0.28-0.38, p50.0083), and the percentage of patients experiencing >1 flarewas significantly lower for all canakinumab doses (15- 27%) vs colchicine (44%, p<0.05). Therewas a 64-72%reduction in the risk of experiencing >1 flare for canakinumab doses >50 mg vs colchicine at 16 weeks (hazard ratio: 0.28-0.36, p50.05). The incidence of adverse events was similar across treatment groups.CONCLUSIONS: Single canakinumab doses >50 mg or four 4-weekly doses provided superior prophylaxis against flares compared with daily colchicine 0.5 mg.

Improved blood pressure control by monitoring compliance with antihypertensive therapy.

Compliance with antihypertensive therapy was monitored for three months using an electronic medication dispenser in 35 patients remaining hypertensive despite the once-daily administration of a blood pressure lowering drug (either as monotherapy or as fixed-dose combination therapy). During the monitoring of compliance, the treatment was unchanged but blood pressure decreased significantly (p < 0.001) from 167.9/100.4 +/- 16.3/7.2 mmHg (mean +/- SD) to 152.5/90.9 +/- 20.9/11.5 mmHg. The percentage of days with one opening per day was 80.8 +/- 20.5. Thus, discussing with the patient about compliance with the prescribed drug regimen and monitoring compliance for a few months allows better control of blood pressure. This most likely reflects increased compliance with antihypertensive drug therapy.

Topische Therapie bei Colitis ulcerosa [Topical therapy of ulcerative colitis].

The availability of new topical preparations for the treatment of left sided ulcerative colitis ulcerosa offers a therapy optimization for many patients. Rectal application of steroids and 5-aminosalicylic acid (5-ASA) is associated with fewer side effects and has a higher therapeutic efficacy in mild to moderate-active left-sided colitis as compared to a systemic therapy. Often it is argued that the patients' compliance is insufficient with a rectal therapy. However, with sufficient information on the proven advantages this is usually not the case. The rectal application of drugs in distal ulcerative colitis is suitable also for the maintenance of remission. Therefore the new therapy guidelines recommend topical therapy more than in former times. Subsequently, these manuscripts focussed specifically on the topical therapy of distal colitis, to elucidate that clear treatment advantages are present in daily practice.

Replacement therapy for iron deficiency improves exercise capacity and quality of life in patients with cyanotic congenital heart disease and/or the Eisenmenger syndrome

La teràpia suplementària de ferro millora la capacitat d’exercici i la qualitat de vida en malalts amb una cardiopatia congènita cianòtica i/ o síndrome d’Eisenmenger El dèficit de ferro és una troballa comú en la cardiopatia congènita cianòtica, i pot ser la causa d’una reducció en la capacitat d’exercici. Actualment, està indicada la reposició dels dipòsits de ferro en aquest grup de malalts, éssent les evidències científiques escasses. En el present treball investiguem la seguretat i eficàcia del tractament amb ferro en malalts amb una cardiopatia congènita cianòtica. Per tal motiu, vint-i-cinc malalts amb una cardiopatia congenita cianòtica i dèficit de ferro van ser inclosos de forma prospectiva entre Agost del 2008 i Gener del 2009. El tractament utilitzat fou fumarat ferròs oral, fins a una dosi màxima de 200 mg tres vegades al dia. En l’anàlisi basal i als tres mesos de seguiment es va utilitzar el test de qualitat de vida “CAMPHOR”, el test de la marxa dels 6 minuts i la prova d’esforç amb consum d’oxigen. L’edat mitja fou 39.9+/-10.9 anys, 80% dones. Catorze malalts tenien la síndrome d’Eisenmenger, sis una malaltia cianòtica complexa i cinc circulació de Fontan. Cap d’ells va haver d'interrompre el tractament degut a efectes adversos. Després de tres mesos de tractament, l’hemoglobina (19.0+/-2.9g/dL a 20.4+/-2.7g/dL, p&0.001), ferritina (13.3+/-4.7mug/L a 54.1+/-24.2mug/L, p&0.001) i saturació de transferrina (17.8+/-9.6% a 34.8+/-23.4%, p&0.001) van augmentar significativament. També hi va haver una millora significativa en la puntuació del test de qualitat de vida (20.7+/-10.9 a 16.2+/-10.4, p=0.001) i el test de la marxa (371.7+/-84.7m a 402.8.0+/-74.9m, p=0.001). No es van evidenciar canvis significatius en els valors de consum d’oxigen (40.7+/-9.2% a 43.8+/-12.4%, p=0.15). En definitiva, la teràpia suplementària amb ferro en els malats amb una cardiopatia congènita cianòtica i dèficit de ferro és segura i millora la qualitat de vida i la capacitat funcional. En aquest grup de malalts, per tant, és aconsellable identificar el dèficit de ferro i restaurar-ne els seus dipòsits.

Electronic monitoring of compliance to lipid-lowering therapy in clinical practice

Nonadherence to treatment is a common problem in the clinical management of hypercholesterolemic patients. This study was carried out with the aim of monitoring the daily compliance to a 6-month course of lipid-lowering therapy, using a microelectronic device, the Medication Event Monitoring System (MEMS), versus pill count. Forty men with primary hypercholesterolemia were prescribed fluvastatin 1 x 40 mg daily, provided in a MEMS package to record the date and time of each opening of the pillbox. Thirty-nine of 40 patients (98%) completed the study. Total cholesterol and LDL cholesterol levels decreased significantly (18% and 25%, p < 0.001) during the 6-month therapy period. A high mean rate of compliance was achieved by MEMS using the following three indexes--compliance to total prescribed dose (88.8% +/- 13.5%), compliance to prescribed days (82.4% +/- 19.5%), and compliance to prescribed time of day (81.86% +/- 19.5%)--and by pill count (93.4% +/- 9.5%). In addition, the MEMS provided some patterns of nonadherence to medication, undetectable by pill count alone, such as a drug holiday in 38% of cases, a drug omission for more than 7 consecutive days in 9% of cases, and, conversely, use of more than the one prescribed daily dose in 47% of cases. A significant correlation between the rate of compliance and the decrease in LDL cholesterol was observed only when the compliance was assessed by MEMS. The results indicate that MEMS is a useful tool for monitoring compliance in clinical practice and may possibly increase adherence to long-term lipid-lowering therapy.

Efficacy, safety and pharmacokinetic of once-daily boosted saquinavir (1500/100 mg) together with 2 nucleos(t)ide reverse transcriptase inhibitors in real life: a multicentre prospective study.

BACKGROUND. Ritonavir-boosted saquinavir (SQVr) is nowadays regarded as an alternative antiretroviral drug probably due to several drawbacks, such as its high pill burden, twice daily dosing and the requirement of 200 mg ritonavir when given at the current standard 1000/100 mg bid dosing. Several once-daily SQVr dosing schemes have been studied with the 200 mg SQV old formulations, trying to overcome some of these disadvantages. SQV 500 mg strength tablets became available at the end of 2005, thus facilitating a once-daily regimen with fewer pills, although there is very limited experience with this formulation yet. METHODS. Prospective, multicentre study in which efficacy, safety and pharmacokinetics of a regimen of once-daily SQVr 1500/100 mg plus 2 NRTIs were evaluated under routine clinical care conditions in either antiretroviral-naïve patients or in those with no previous history of antiretroviral treatments and/or genotypic resistance tests suggesting SQV resistance. Plasma SQV trough levels were measured by HPLV-UV. RESULTS. Five hundred and fourteen caucasian patients were included (47.2% coinfected with hepatitis C and/or B virus; 7.8% with cirrhosis). Efficacy at 52 weeks (plasma RNA-HIV <50 copies/ml) was 67.7% (CI95: 63.6 - 71.7%) by intention-to-treat, and 92.2% (CI95: 89.8 - 94.6%) by on-treatment analysis. The reasons for failure were: dropout or loss to follow-up (18.4%), virological failure (7.8%), adverse events (3.1%), and other reasons (4.6%). The high rate of dropout may be explained by an enrollment and follow-up under routine clinical care condition, and a population with a significant number of drug users. The median SQV Cmin (n = 49) was 295 ng/ml (range, 53-2172). The only variable associated with virological failure in the multivariate analysis was adherence (OR: 3.36; CI95, 1.51-7.46, p = 0.003). CONCLUSIONS. Our results suggests that SQVr (1500/100 mg) once-daily plus 2 NRTIs is an effective regimen, without severe clinical adverse events or hepatotoxicity, scarce lipid changes, and no interactions with methadone. All these factors and its once-daily administration suggest this regimen as an appropriate option in patients with no SQV resistance-associated mutations.

Targeting anticancer therapy : clinical and preclinical approaches

AbstractCancer treatment has shifted from cytotoxic and nonspecific chemotherapy to chronic treatment with targeted molecular therapies. These new classes of drugs directed against cancer-specific molecules and signaling pathways, act at a particular level of the tumor cell development. However, in both types of therapeutic approaches (standard cytotoxic chemotherapy and targeted signal transduction inhibitions), toxicity and side effects can occur. The aim of this thesis was to investigate various approaches to improve the activity and tolerability of cancer treatment, in a clinical setting, a) by molecular targeting through the use of tyrosine kinase inhibitors (TKIs), whose dosage can be adapted to each patient according to plasma levels, and, b) in a preclinical model, by tissue targeting with locoregional administration of cytotoxic chemotherapy to increase drug exposure in the target tissue while reducing systemic toxicity of the treatment.A comprehensive program for the Therapeutic Drug Monitoring (TDM) of the new class of targeted anticancer drugs of TKIs in patient's blood has been therefore initiated comprising the setting up, validation and clinical application of a multiplex assay by liquid chromatography coupled to tandem mass spectrometry of TKIs in plasma from cancer patients. Information on drugs exposure may be clinically useful for an optimal follow-up of patients' anticancer treatment, especially in case of less than optimal clinical response, occurrence of adverse drug reaction effects and the numerous risks of drug-drug interactions. In this context, better knowledge of the potential drug interactions between TKIs and widely prescribed co- medications is of critical importance for clinicians, to improve their daily care of cancer patients. For one of the first TKI imatinib, TDM interpretation is nowadays based on total plasma concentrations but, only the unbound (free) form is likely to enter cell to exert its pharmacological action. Pharmacokinetic analysis of the total and free plasma level of imatinib measured simultaneously in patients have allowed to refine and validate a population pharmacokinetic model integrating factors influencing in patients the exposure of pharmacological active species. The equation developed from this model may be used for extrapolating free imatinib plasma concentration based on the total plasma levels that are currently measured in TDM from patients. Finally, the specific influence of Pglycoprotein on the intracellular disposition of TKIs has been studies in cell systems using the siRNA silencing approach.Another approach to enhance the selectivity of anticancer treatment may be achieved by the loco-regional administration of a cytostatic agent to the target organ while sparing non- affected tissues. Isolated lung perfusion (ILP) was designed for the treatment of loco-regional malignancies of the lung but clinical results have been so far disappointing. It has been shown in a preclinical model in rats that ILP with the cytotoxic agent doxorubicin alone allows a high drug uptake in lung tissue, and a low systemic toxicity, but was characterized by a high spatial tissular heterogeneity in drug exposure and doxorubicin uptake in tumor was comparatively smaller than in normal lung tissue. Photodynamic therapy (PDT) is a new approach for the treatment of superficial tumors, and implies the application of a sensitizer activated by a laser light at a specific wavelength, that disrupts endothelial barrier of tumor vessels to increase locally the distribution of cytostatics into the tumor tissue. PDT pre-treatment before intravenous administration of liposomal doxorubicin was indeed shown to selectively increase drug uptake in tumors in a rat model of sarcoma tumors to the lung.RésuméLe traitement de certains cancers s'est progressivement transformé et est passé de la chimiothérapie, cytotoxique et non spécifique, au traitement chronique des patients avec des thérapies moléculaires ciblées. Ces médicaments ont une action ciblée en interférant à un niveau spécifique du développement de la cellule tumorale. Dans les deux types d'approches thérapeutiques (chimiothérapie cytotoxique et traitements ciblés), on est confronté à la présence de toxicité et aux effets secondaires du traitement anticancéreux. Le but de cette thèse a donc été d'étudier diverses approches visant à améliorer l'efficacité et la tolérabilité du traitement anticancéreux, a) dans le cadre d'une recherche clinique, par le ciblage moléculaire grâce aux inhibiteurs de tyrosines kinases (TKIs) dont la posologie est adaptée à chaque patient, et b) dans un modèle préclinique, par le ciblage tissulaire grâce à l'administration locorégionale de chimiothérapie cytotoxique, afin d'augmenter l'exposition dans le tissu cible et de réduire la toxicité systémique du traitement.Un programme de recherche sur le suivi thérapeutique (Therapeutic Drug Monitoring, TDM) des inhibiteurs de tyrosine kinases a été ainsi mis en place et a impliqué le développement, la validation et l'application clinique d'une méthode multiplex par chromatographie liquide couplée à la spectrométrie de masse en tandem des TKIs chez les patients souffrant de cancer. L'information fournie par le TDM sur l'exposition des patients aux traitements ciblés est cliniquement utile et est susceptible d'optimiser la dose administrée, notamment dans les cas où la réponse clinique au traitement des patients est sous-optimale, en présence d'effets secondaires du traitement ciblé, ou lorsque des risques d'interactions médicamenteuses sont suspectés. Dans ce contexte, l'étude des interactions entre les TKIs et les co-médications couramment associées est utile pour les cliniciens en charge d'améliorer au jour le jour la prise en charge du traitement anticancéreux. Pour le premier TKI imatinib, l'interprétation TDM est actuellement basée sur la mesure des concentrations plasmatiques totales alors que seule la fraction libre (médicament non lié aux protéines plasmatiques circulantes) est susceptible de pénétrer dans la cellule pour exercer son action pharmacologique. L'analyse pharmacocinétique des taux plasmatiques totaux et libres d'imatinib mesurés simultanément chez les patients a permis d'affiner et de valider un modèle de pharmacocinétique de population qui intègre les facteurs influençant l'exposition à la fraction de médicament pharmacologiquement active. L'équation développée à partir de ce modèle permet d'extrapoler les concentrations libres d'imatinib à partir des concentrations plasmatiques totales qui sont actuellement mesurées lors du TDM des patients. Finalement, l'influence de la P-glycoprotéine sur la disposition cellulaire des TKIs a été étudiée dans un modèle cellulaire utilisant l'approche par la technologie du siRNA permettant de bloquer sélectivement l'expression du gène de cette protéine d'efflux des médicaments.Une autre approche pour augmenter la sélectivité du traitement anticancéreux consiste en une administration loco-régionale d'un agent cytostatique directement au sein de l'organe cible tout en préservant les tissus sains. La perfusion isolée du poumon (ILP) a été conçue pour le traitement loco-régional des cancers affectant les tissus pulmonaires mais les résultats cliniques ont été jusqu'à ce jour décevants. Dans des modèles précliniques chez le rat, il a pu être démontré que l'ILP avec la doxorubicine, un agent cytotoxique, administré seul, permet une exposition élevée au niveau du tissu pulmonaire, et une faible toxicité systémique. Toutefois, cette technique est caractérisée par une importante variabilité de la distribution dans les tissus pulmonaires et une pénétration du médicament au sein de la tumeur comparativement plus faible que dans les tissus sains.La thérapie photodynamique (PDT) est une nouvelle approche pour le traitement des tumeurs superficielles, qui consiste en l'application d'un agent sensibilisateur activé par une lumière laser de longueur d'onde spécifique, qui perturbe l'intégrité physiologique de la barrière endothéliale des vaisseaux alimentant la tumeur et permet d'augmenter localement la pénétration des agents cytostatiques.Nos études ont montré qu'un pré-traitement par PDT permet d'augmenter sélectivement l'absorption de doxorubicine dans les tumeurs lors d'administration i.v. de doxorubicine liposomale dans un modèle de sarcome de poumons de rongeurs.Résumé large publicDepuis une dizaine d'année, le traitement de certains cancers s'est progressivement transformé et les patients qui devaient jusqu'alors subir des chimiothérapies, toxiques et non spécifiques, peuvent maintenant bénéficier de traitements chroniques avec des thérapies ciblées. Avec les deux types d'approches thérapeutiques, on reste cependant confronté à la toxicité et aux effets secondaires du traitement.Le but de cette thèse a été d'étudier chez les patients et dans des modèles précliniques les diverses approches visant à améliorer l'activité et la tolérance des traitements à travers un meilleur ciblage de la thérapie anticancéreuse. Cet effort de recherche nous a conduits à nous intéresser à l'optimisation du traitement par les inhibiteurs de tyrosines kinases (TKIs), une nouvelle génération d'agents anticancéreux ciblés agissant sélectivement sur les cellules tumorales, en particulier chez les patients souffrant de leucémie myéloïde chronique et de tumeurs stromales gastro-intestinales. L'activité clinique ainsi que la toxicité de ces TKIs paraissent dépendre non pas de la dose de médicament administrée, mais de la quantité de médicaments circulant dans le sang auxquelles les tumeurs cancéreuses sont exposées et qui varient beaucoup d'un patient à l'autre. A cet effet, nous avons développé une méthode par chromatographie couplée à la spectrométrie de masse pour mesurer chez les patients les taux de médicaments de la classe des TKIs dans la perspective de piloter le traitement par une approche de suivi thérapeutique (Therapeutic Drug Monitoring, TDM). Le TDM repose sur la mesure de la quantité de médicament dans le sang d'un patient dans le but d'adapter individuellement la posologie la plus appropriée: des quantités insuffisantes de médicament dans le sang peuvent conduire à un échec thérapeutique alors qu'un taux sanguin excessif peut entraîner des manifestations toxiques.Dans une seconde partie préclinique, nous nous sommes concentrés sur l'optimisation de la chimiothérapie loco-régionale dans un modèle de sarcome du poumon chez le rat, afin d'augmenter l'exposition dans la tumeur tout en réduisant la toxicité dans les tissus non affectés.La perfusion isolée du poumon (ILP) permet d'administrer un médicament anticancéreux cytotoxique comme la doxorubicine, sélectivement au niveau le tissu pulmonaire où sont généralement localisées les métastases de sarcome. L'administration par ILP de doxorubicine, toxique pour le coeur, a permis une forte accumulation des médicaments dans le poumon, tout en épargnant le coeur. Il a été malheureusement constaté que la doxorubicine ne pénètre que faiblement dans la tumeur sarcomateuse, témoignant des réponses cliniques décevantes observées avec cette approche en clinique. Nous avons ainsi étudié l'impact sur la pénétration tumorale de l'association d'une chimiothérapie cytotoxique avec la thérapie photodynamique (PDT) qui consiste en l'irradiation spécifique du tissu-cible cancéreux, après l'administration d'un agent photosensibilisateur. Dans ce modèle animal, nous avons observé qu'un traitement par PDT permet effectivement d'augmenter de façon sélective l'accumulation de doxorubicine dans les tumeurs lors d'administration intraveineuse de médicament.

L'examen neuropsychologique en pratique quotidienne [Neuropsychological test in daily practice]

Neuropsychology is a scientific discipline, born in the XIX century, and bridges the fields of neurology and psychology. Neuropsychologists apply scientific knowledge about the relationship between brain function and mental performances. The major clinical role of a neuropsychological evaluation is to help to establish medical and functional diagnosis in patients (adults or infants) with different neurological pathologies such as stroke, traumatic brain injury, dementia, epilepsy.... Such analysis necessitates accurate observation of behaviour and administration of tests of mental abilities (e.g. language, memory...). Test results can also help to clarify the nature of cognitive difficulties and to support the formulation of plans for neuropsychological therapy and functional adjustment in every day life.

Self-reported alcohol consumption and its association with adherence and outcome of antiretroviral therapy in the Swiss HIV Cohort Study.

BACKGROUND: Alcohol consumption leading to morbidity and mortality affects HIV-infected individuals. Here, we aimed to study self-reported alcohol consumption and to determine its association with adherence to antiretroviral therapy (ART) and HIV surrogate markers. METHODS: Cross-sectional data on daily alcohol consumption from August 2005 to August 2007 were analysed and categorized according to the World Health Organization definition (light, moderate or severe health risk). Multivariate logistic regression models and Pearson's chi(2) statistics were used to test the influence of alcohol use on endpoints. RESULTS: Of 6,323 individuals, 52.3% consumed alcohol less than once a week in the past 6 months. Alcohol intake was deemed light in 39.9%, moderate in 5.0% and severe in 2.8%. Higher alcohol consumption was significantly associated with older age, less education, injection drug use, being in a drug maintenance programme, psychiatric treatment, hepatitis C virus coinfection and with a longer time since diagnosis of HIV. Lower alcohol consumption was found in males, non-Caucasians, individuals currently on ART and those with more ART experience. In patients on ART (n=4,519), missed doses and alcohol consumption were positively correlated (P<0.001). Severe alcohol consumers, who were pretreated with ART, were more often off treatment despite having CD4+ T-cell count <200 cells/microl; however, severe alcohol consumption per se did not delay starting ART. In treated individuals, alcohol consumption was not associated with worse HIV surrogate markers. CONCLUSIONS: Higher alcohol consumption in HIV-infected individuals was associated with several psychosocial and demographic factors, non-adherence to ART and, in pretreated individuals, being off treatment despite low CD4+ T-cell counts.