936 resultados para phase rule one component


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BACKGROUND: Glioblastoma, the most common adult primary malignant brain tumor, confers poor prognosis (median survival of 15 months) notwithstanding aggressive treatment. Combination chemotherapy including carmustine (BCNU) or temozolomide (TMZ) with the MGMT inhibitor O6-benzylguanine (O6BG) has been used, but has been associated with dose-limiting hematopoietic toxicity. OBJECTIVE: To assess safety and efficacy of a retroviral vector encoding the O6BG-resistant MGMTP140K gene for transduction and autologous transplantation of hematopoietic stem cells (HSCs) in MGMT unmethylated, newly diagnosed glioblastoma patients in an attempt to chemoprotect bone marrowduring combination O6BG/TMZ therapy. METHODS: Three patients have been enrolled in the first cohort. Patients underwent standard radiation therapy without TMZ followed by G-CSF mobilization, apheresis, and conditioning with 600 mg/m2 BCNU prior to infusion of gene-modified cells. Posttransplant, patients were treated with 28-day cycles of single doseTMZ (472 mg/m2) with 48-hour intravenous O6BG (120 mg/m2 bolus, then 30 mg/m2/d). RESULTS: The BCNU dose was nonmyeloablative with ANC ,500/mL for ≤3 d and nadir thrombocytopenia of 28,000/mL. Gene marking in pre-infusion colony forming units (CFUs) was 70.6%, 79.0%, and 74.0% in Patients 1, 2, and 3, respectively, by CFU-PCR. Following engraftment, gene marking in white blood cells and sorted granulocytes ranged between 0.37-0.84 and 0.33-0.83 provirus copies, respectively, by real-time PCR. Posttransplant gene marking in CFUs from CD34-selected cells ranged from 28.5% to 47.4%. Patients have received 4, 3, and 2 cycles of O6BG/TMZ, respectively, with evidence for selection of gene-modified cells. One patient has received a single dose-escalated cycle at 590 mg/m2 TMZ. No additional extra-hematopoietic toxicity has been observed thus far and all three patients exhibit stable disease at 7-8 months since diagnosis CONCLUSIONS: We believe that these data demonstrate the feasibility of achieving significant engraftment of MGMTP140K-modified cells with a well-tolerated dose of BCNU. Further follow-up will determine whether this approach will allow for further dose escalation of TMZ and improved survival.

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Amplification of the epidermal growth factor receptor (EGFR) gene is one of the most common oncogenic alterations in glioblastoma (45%) making it a prime target for therapy. However, small molecule inhibitors of the EGFR tyrosine kinase showed disappointing efficacy in clinical trials for glioblastoma. Here we aimed at investigating the molecular effects of the tyrosine kinase inhibitor gefitinib on the EGFR signaling pathway in human glioblastoma. Twenty-two patients selected for reoperation of recurrent glioblastoma were treated within a phase II trial for 5 days with 500 mg gefitinib before surgery followed by postoperative gefitinib until recurrence. Resected glioblastoma tissues exhibited high concentrations of gefitinib (median, 4.1 μg/g), 20 times higher than respective plasma. EGFR-pathway activity was evaluated with phosphorylation-specific assays. The EGFR was efficiently dephosphorylated in treated patients as compared to a control cohort of 12 patients. However, no significant effect on 12 pathway constituents was detected. In contrast, in vitro treatment of a glioblastoma cell line, BS-153, with endogenous EGFRwt amplification and EGFRvIII expression resulted not only in dephosphorylation of the EGFR, but also of key regulators in the pathway such as AKT. Treating established xenografts of the same cell line as an in vivo model showed dephosphorylation of the EGFR without affecting downstream signal transductors, similar to the human glioblastoma. Taken together, gefitinib reaches high concentrations in the tumor tissue and efficiently dephosphorylates its target. However, regulation of downstream signal transducers in the EGFR pathway seems to be dominated by regulatory circuits independent of EGFR phosphorylation.

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PURPOSE: The origin of the slow component is not fully understood. The mechanical hypothesis is one of the potential factors, because an increase in external mechanical work with fatigue was previously reported for a constant velocity run. The purpose of this study was to determine whether a change in mechanical work could occur during the development of the VO2 slow component under the effect of fatigue. METHODS: Twelve regional-level competitive runners performed a square-wave transition, corresponding to 95% of the speed associated with peak VO2 obtained during an incremental test. The VO2 response was fit with a classical model including two exponential functions. A specific treadmill with three-dimensional force transducers was used to measure the ground reaction force. Kinetic work (W(kin)), potential work (W(pot)), external work (W(ext)), and an index of internal work (W(int)) per unit of distance were quantified continuously. RESULTS: During the slow component of VO2, a significant increase in W (P< 0.01), no change in W, and a significant decrease in W and W index (P< 0.05, P< 0.001, respectively) were observed. CONCLUSION: The present study showed that the slow component of VO2 did not result partly from a change in mechanical work under the effect of fatigue. Nevertheless, the decrease in stride frequency (P< 0.001) and contact time (P< 0.001) suggested an alternative mechanical explanation. The slow component during running may be due to the cost of generating force or to alterations in the storage and recoil of elastic energy, and not to the external mechanical work.

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The contribution of respiratory muscle work to the development of the O(2) consumption (Vo(2)) slow component is a point of controversy because it has been shown that the increased ventilation in hypoxia is not associated with a concomitant increase in Vo(2) slow component. The first purpose of this study was thus to test the hypothesis of a direct relationship between respiratory muscle work and Vo(2) slow component by manipulating inspiratory resistance. Because the conditions for a Vo(2) slow component specific to respiratory muscle can be reached during intense exercise, the second purpose was to determine whether respiratory muscles behave like limb muscles during heavy exercise. Ten trained subjects performed two 8-min constant-load heavy cycling exercises with and without a threshold valve in random order. Vo(2) was measured breath by breath by using a fast gas exchange analyzer, and the Vo(2) response was modeled after removal of the cardiodynamic phase by using two monoexponential functions. As anticipated, when total work was slightly increased with loaded inspiratory resistance, slight increases in base Vo(2), the primary phase amplitude, and peak Vo(2) were noted (14.2%, P < 0.01; 3.5%, P > 0.05; and 8.3%, P < 0.01, respectively). The bootstrap method revealed small coefficients of variation for the model parameter, including the slow-component amplitude and delay (15 and 19%, respectively), indicating an accurate determination for this critical parameter. The amplitude of the Vo(2) slow component displayed a 27% increase from 8.1 +/- 3.6 to 10.3 +/- 3.4 ml. min(-1). kg(-1) (P < 0.01) with the addition of inspiratory resistance. Taken together, this increase and the lack of any differences in minute volume and ventilatory parameters between the two experimental conditions suggest the occurrence of a Vo(2) slow component specific to the respiratory muscles in loaded condition.

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Résumé : Emotion et cognition sont deux termes généralement employés pour désigner des processus psychiques de nature opposée. C'est ainsi que les sciences cognitives se sont longtemps efforcées d'écarter la composante «chaude »des processus «froids »qu'elles visaient, si ce n'est pour montrer l'effet dévastateur de la première sur les seconds. Pourtant, les processus cognitifs (de collecte, maintien et utilisation d'information) et émotioAnels (d'activation subjective, physiologique et comportementale face à ce qui est attractif ou aversif) sont indissociables. Par l'approche neuro-éthologique, à l'interface entre le substrat biologique et les manifestations comportementales, nous nous sommes intéressés à une fonction cognitive essentielle, la fonction mnésique, classiquement exprimée chez le rongeur par l'orientation spatiale. Au niveau du substrat, McDonald et White (1993) ont montré la dissociation de trois systèmes de mémoire, avec les rôles de l'hippocampe, du néostriatum et de l'amygdale dans l'encodage des informations respectivement épisodiques, procédurales et émotionnelles. Nous nous sommes penchés sur l'interaction entre ces systèmes en fonction de la dimension émotionnelle par l'éclairage du comportement. L'état émotionnel de l'animal dépend de plusieurs facteurs, que nous avons tenté de contrôler indirectement en comparant leurs effets sur l'acquisition, dans diverses conditions, de la tâche de Morris (qui nécessite la localisation dans un bassin de la position d'une plate-forme submergée), ainsi que sur le style d'exploration de diverses arènes, ouvertes ou fermées, plus ou moins structurées par la présence de tunnels en plexiglas transparent. Nous avons d'abord exploré le rôle d'un composant du système adrénergique dans le rapport à la difficulté et au stress, à l'aide de souris knock-out pour le récepteur à la noradrénaline a-1 B dans un protocole avec 1 ou 4 points de départ dans un bassin partitionné. Ensuite, nous nous sommes penchés, chez le rat, sur les effets de renforcement intermittent dans différentes conditions expérimentales. Dans ces conditions, nous avons également tenté d'analyser en quoi la situation du but dans un paysage donné pouvait interférer avec les effets de certaines formes de stress. Finalement, nous avons interrogé les conséquences de perturbations passées, y compris le renforcement partiel, sur l'organisation des déplacements sur sol sec. Nos résultats montrent la nécessité, pour les souris cont~ô/es dont l'orientation repose sur l'hippocampe, de pouvoir varier les trajectoires, ce qui favoriserait la constitution d'une carte cognitive. Les souris a->B KO s'avèrent plus sensibles au stress et capables de bénéficier de la condition de route qui permet des réponses simples et automatisées, sous-tendues par l'activité du striatum. Chez les rats en bassin 100% renforcé, l'orientation apparaît basée sur l'hippocampe, relayée par le striatum pour le développement d'approches systématiques et rapides, avec réorientation efficace en nouvelle position par réactivation dépendant de l'hippocampe. A 50% de renforcement, on observe un effet du type de déroulement des sessions, transitoirement atténué par la motivation Lorsque les essais s'enchaînent sans pause intrasession, les latences diminuent régulièrement, ce qui suggère une prise en charge possible par des routines S-R dépendant du striatum. L'organisation des mouvements exploratoires apparaît dépendante du niveau d'insécurité, avec différents profils intermédiaires entre la différentiation maximale et la thigmotaxie, qui peuvent être mis en relation avec différents niveaux d'efficacité de l'hippocampe. Ainsi, notre travail encourage à la prise en compte de la dimension émotionnelle comme modulatrice du traitement d'information, tant en phase d'exploration de l'environnement que d'exploitation des connaissances spatiales. Abstract : Emotion and cognition are terms widely used to refer to opposite mental processes. Hence, cognitive science research has for a long time pushed "hot" components away from "cool" targeted processes, except for assessing devastating effects of the former upon the latter. However, cognitive processes (of information collection, preservation, and utilization) and emotional processes (of subjective, physiological, and behavioral activation roue to attraction or aversion) are inseparable. At the crossing between biological substrate and behavioral expression, we studied a chief cognitive function, memory, classically shown in animals through spatial orientation. At the substrate level, McDonald et White (1993) have shown a dissociation between three memory systems, with the hippocampus, neostriatum, and amygdala, encoding respectively episodic, habit, and emotional information. Through the behavior of laboratory rodents, we targeted the interaction between those systems and the emotional axis. The emotional state of an animal depends on different factors, that we tried to check in a roundabout way by the comparison of their effects on acquisition, in a variety of conditions, of the Morris task (in which the location of a hidden platform in a pool is required), as well as on the exploration profile in different apparatus, open-field and closed mazes, more or less organized by clear Plexiglas tunnels. We first tracked the role, under more or less difficult and stressful conditions, of an adrenergic component, with knock-out mice for the a-1 B receptor in a partitioned water maze with 1 or 4 start positions. With rats, we looked for the consequences of partial reinforcement in the water maze in different experimental conditions. In those conditions, we further analyzed how the situation of the goal in the landscape could interfere with the effect of a given stress. At last, we conducted experiments on solid ground, in an open-field and in radial mazes, in order to analyze the organization of spatial behavior following an aversive life event, such as partial reinforcement training in the water maze. Our results emphasize the reliance of normal mice to be able to vary approach trajectories. One of our leading hypotheses is that such strategies are hippocampus-dependent and are best developed for of a "cognitive map like" representation. Alpha-1 B KO mice appear more sensitive to stress and able to take advantage of the route condition allowing simple and automated responses, most likely striatum based. With rats in 100% reinforced water maze, the orientation strategy is predominantly hippocampus dependent (as illustrated by the impairment induced by lesions of this structure) and becomes progressively striatum dependent for the development of systematic and fast successful approaches. Training towards a new platform position requires a hippocampus based strategy. With a 50% reinforcement rate, we found a clear impairment related to intersession disruption, an effect transitorily minimized by motivation enhancement (cold water). When trials are given without intrasession interruption, latencies consistently diminish, suggesting a possibility for striatum dependent stimulus-response routine to occur. The organization of exploratory movements is shown to depend on the level of subjective security, with different intermediary profiles between maximum differentiation and thigmotaxy, which can be considered in parallel with different efficiency levels of the hippocampus dependent strategies. Thus, our work fosters the consideration of emotion as a cognitive treatment modulator, during spatial exploration as well as spatial learning. It leads to a model in which the predominance of hippocampus based exploration is challenged by training conditions of various nature.

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BACKGROUND: To improve the efficacy of first-line therapy for advanced non-small cell lung cancer (NSCLC), additional maintenance chemotherapy may be given after initial induction chemotherapy in patients who did not progress during the initial treatment, rather than waiting for disease progression to administer second-line treatment. Maintenance therapy may consist of an agent that either was or was not present in the induction regimen. The antifolate pemetrexed is efficacious in combination with cisplatin for first-line treatment of advanced NSCLC and has shown efficacy as a maintenance agent in studies in which it was not included in the induction regimen. We designed a phase III study to determine if pemetrexed maintenance therapy improves progression-free survival (PFS) and overall survival (OS) after cisplatin/pemetrexed induction therapy in patients with advanced nonsquamous NSCLC. Furthermore, since evidence suggests expression levels of thymidylate synthase, the primary target of pemetrexed, may be associated with responsiveness to pemetrexed, translational research will address whether thymidylate synthase expression correlates with efficacy outcomes of pemetrexed. METHODS/DESIGN: Approximately 900 patients will receive four cycles of induction chemotherapy consisting of pemetrexed (500 mg/m2) and cisplatin (75 mg/m2) on day 1 of a 21-day cycle. Patients with an Eastern Cooperative Oncology Group performance status of 0 or 1 who have not progressed during induction therapy will randomly receive (in a 2:1 ratio) one of two double-blind maintenance regimens: pemetrexed (500 mg/m2 on day 1 of a 21-day cycle) plus best supportive care (BSC) or placebo plus BSC. The primary objective is to compare PFS between treatment arms. Secondary objectives include a fully powered analysis of OS, objective tumor response rate, patient-reported outcomes, resource utilization, and toxicity. Tumor specimens for translational research will be obtained from consenting patients before induction treatment, with a second biopsy performed in eligible patients following the induction phase. DISCUSSION: Although using a drug as maintenance therapy that was not used in the induction regimen exposes patients to an agent with a different mechanism of action, evidence suggests that continued use of an agent present in the induction regimen as maintenance therapy enables the identification of patients most likely to benefit from maintenance treatment.

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Purpose : To establish the feasibility and tolerability of gefitinib (ZD1839, Iressa) with radiation (RT) or concurrent chemoradiation (CRT) with cisplatin (CDDP) in patients with advanced non small cell lung cancer (NSCLC).Patients and Methods : In this multicenter Phase I study, 5 patients with unresectable NSCLC received 250 mg gefitinib daily starting 1 week before RT at a dose of 63 Gy (Step 1). After a first safety analysis, 9 patients were treated daily with 250 mg gefitinib plus CRT in the form of RT and weekly CDDP 35 mg/m(2) (Step 2). Gefitinib was maintained for up to 2 years until disease progression or toxicity.Results : Fourteen patients were assessed in the two steps. In Step 1 (five patients were administered only gefitinib and RT), no lung toxicities were seen, and there was no dose-limiting toxicity (DLT). Adverse events were skin and subcutaneous tissue reactions, limited to Grade 1-2. In Step 2, two of nine patients (22.2%) had DLT. One patient suffered from dyspnea and dehydration associated with neutropenic pneumonia, and another showed elevated liver enzymes. In both steps combined, 5 of 14 patients (35.7%) experienced one or more treatment interruptions.Conclusions : Gefitinib (250 mg daily) in combination with RT and CDDP in patients with Stage HI NSCLC is feasible, but CDDP likely enhances toxicity. The impact of gefitinib on survival and disease control as a first-line treatment in combination with RT remains to be determined. (C) 2011 Elsevier Inc.

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The pathogenesis and evolutive pattern of Chagas disease suggests that the chronic phase should be more widely treated in order to (i) eliminate Trypanosoma cruzi and prevent new inflammatory foci and the extension of tissue lesions, (ii) promote tissue regeneration to prevent fibrosis, (iii) reverse existing fibrosis, (iv) prevent cardiomyopathy, megaoesophagus and megacolon and (v) reduce or eliminate cardiac block and arrhythmia. All cases of the indeterminate chronic form of Chagas disease without contraindications due to other concomitant diseases or pregnancy should be treated and not only cases involving children or recently infected cases. Patients with chronic Chagas cardiomyopathy grade II of the New York Heart Association classification should be treated with specific chemotherapy and grade III can be treated according to medical-patient decisions. We are proposing the following new strategies for chemotherapeutic treatment of the chronic phase of Chagas disease: (i) repeated short-term treatments for 30 consecutive days and interval of 30-60 days for six months to one year and (ii) combinations of drugs with different mechanisms of action, such as benznidazole + nifurtimox, benznidazole or nifurtimox + allopurinol or triazole antifungal agents, inhibition of sterol synthesis.

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BACKGROUND: The human herpes simplex virus-associated host cell factor 1 (HCF-1) is a conserved human transcriptional co-regulator that links positive and negative histone modifying activities with sequence-specific DNA-binding transcription factors. It is synthesized as a 2035 amino acid precursor that is cleaved to generate an amino- (HCF-1(N)) terminal subunit, which promotes G1-to-S phase progression, and a carboxy- (HCF-1(C)) terminal subunit, which controls multiple aspects of cell division during M phase. The HCF-1(N) subunit contains a Kelch domain that tethers HCF-1 to sequence-specific DNA-binding transcription factors, and a poorly characterized so called "Basic" region (owing to a high ratio of basic vs. acidic amino acids) that is required for cell proliferation and has been shown to associate with the Sin3 histone deacetylase (HDAC) component. Here we studied the role of the Basic region in cell proliferation and G1-to-S phase transition assays. METHODOLOGY/PRINCIPAL FINDINGS: Surprisingly, much like the transcriptional activation domains of sequence-specific DNA-binding transcription factors, there is no unique sequence within the Basic region required for promoting cell proliferation or G1-to-S phase transition. Indeed, the ability to promote these activities is size dependent such that the shorter the Basic region segment the less activity observed. We find, however, that the Basic region requirements for promoting cell proliferation in a temperature-sensitive tsBN67 cell assay are more stringent than for G1-to-S phase progression in an HCF-1 siRNA-depletion HeLa-cell assay. Thus, either half of the Basic region alone can support G1-to-S phase progression but not cell proliferation effectively in these assays. Nevertheless, the Basic region displays considerable structural plasticity because each half is able to promote cell proliferation when duplicated in tandem. Consistent with a potential role in promoting cell-cycle progression, the Sin3a HDAC component can associate independently with either half of the Basic region fused to the HCF-1 Kelch domain. CONCLUSIONS/SIGNIFICANCE: While conserved, the HCF-1 Basic region displays striking structural flexibility for controlling cell proliferation.

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Trypanosoma cruzi infection induces progressive cardiac inflammation that leads to fibrosis and modifications in the heart architecture and functionality. Statins, such as 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors, have been studied due to their pleiotropic roles in modulating the inflammatory response. Our goal was to evaluate the effects of simvastatin on the cardiac inflammatory process using a cardiotropic strain of T. cruzi in a murine model of Chagas cardiomyopathy. C57BL/6 mice were infected with 500 trypomastigotes of the Colombian strain of T. cruzi and treated with an oral dose of simvastatin (20 mg/Kg/day) for one month and inflammatory and morphometric parameters were subsequently evaluated in the serum and in the heart, respectively. Simvastatin reduced the total cholesterol and inflammatory mediators (interferon-gamma, tumour necrosis factor-alpha, CCL2 and CCL5) in the serum and in the heart tissue at 30 days post-infection. Additionally, a proportional reduction in heart weight and inflammatory infiltration was observed. Simvastatin also reduced epimastigote proliferation in a dose-dependent manner in vitro and was able to reduce blood trypomastigotes and heart amastigote nests during the acute phase of Chagas disease in vivo. Based on these data, we conclude that simvastatin exerts a modulatory effect on the inflammatory mediators that are elicited by the Colombian strain of T. cruzi and ameliorates the heart damage that is observed in a murine model of Chagas disease.

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BACKGROUND AND OBJECTIVES The elective treatment of patients with post-transplant lymphoproliferative disorders is controversial. The purpose of this trial was to evaluate the efficacy of treatment with extended doses of rituximab adapted to the response in patients with post-transplant lymphoproliferative disorders after solid organ transplantation. DESIGN AND METHODS This was a prospective, multicenter, phase II trial. Patients were treated with reduction of immunosuppression and four weekly infusions of rituximab. Those patients who did not achieve complete remission (CR) received a second course of four rituximab infusions. The primary end-point of the study was the CR rate. RESULTS Thirty-eight patients were assesable. One episode of grade 4 neutropenia was the only severe adverse event observed. After the first course of rituximab, 13 (34.2%) patients achieved CR, 8 patients did not respond, and 17 patients achieved partial remission. Among those 17 patients, 12 could be treated with a second course of rituximab, and 10 (83.3%) achieved CR, yielding an intention-to-treat CR rate of 60.5%. Eight patients excluded from the trial because of absence of CR were treated with rituximab combined with chemotherapy, and six (75%) achieved CR. Event-free survival was 42% and overall survival was 47% at 27.5 months. Fourteen patients died, ten of progression of their post-transplant lymphoproliferative disorder. INTERPRETATION AND CONCLUSIONS These results confirm that extended treatment with rituximab can obtain a high rate of CR in patients with post-transplant lymphoproliferative disorders after solid organ transplantation without increasing toxicity, and should be recommended as initial therapy for these patients.

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This is one of the few studies that have explored the value of baseline symptoms and health-related quality of life (HRQOL) in predicting survival in brain cancer patients. Baseline HRQOL scores (from the EORTC QLQ-C30 and the Brain Cancer Module (BN 20)) were examined in 490 newly diagnosed glioblastoma cancer patients for the relationship with overall survival by using Cox proportional hazards regression models. Refined techniques as the bootstrap re-sampling procedure and the computation of C-indexes and R(2)-coefficients were used to try and validate the model. Classical analysis controlled for major clinical prognostic factors selected cognitive functioning (P=0.0001), global health status (P=0.0055) and social functioning (P<0.0001) as statistically significant prognostic factors of survival. However, several issues question the validity of these findings. C-indexes and R(2)-coefficients, which are measures of the predictive ability of the models, did not exhibit major improvements when adding selected or all HRQOL scores to clinical factors. While classical techniques lead to positive results, more refined analyses suggest that baseline HRQOL scores add relatively little to clinical factors to predict survival. These results may have implications for future use of HRQOL as a prognostic factor in cancer patients.

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BACKGROUND Cabazitaxel is approved in patients with metastatic hormone-refractory prostate cancer previously treated with a docetaxel-containing regimen. This study evaluated a weekly cabazitaxel dosing regimen. Primary objectives were to report dose-limiting toxicities (DLTs) and to determine the maximum tolerated dose (MTD). Efficacy, safety and pharmacokinetics were secondary objectives. METHODS Cabazitaxel was administered weekly (1-hour intravenous infusion at 1.5-12 mg/m2 doses) for the first 4 weeks of a 5-week cycle in patients with solid tumours. Monitoring of DLTs was used to determine the MTD and the recommended weekly dose. RESULTS Thirty-one patients were enrolled. Two of six patients experienced DLTs at 12 mg/m2, which was declared the MTD. Gastrointestinal disorders were the most common adverse event. Eight patients developed neutropenia (three ≥ Grade 3); one occurrence of febrile neutropenia was reported. There were two partial responses (in breast cancer) and 13 patients had stable disease (median duration of 3.3 months). Increases in Cmax and AUC0-t were dose proportional for the 6-12 mg/m2 doses. CONCLUSION The MTD of weekly cabazitaxel was 12 mg/m2 and the recommended weekly dose was 10 mg/m2. The observed safety profile and antitumour activity of cabazitaxel were consistent with those observed with other taxanes in similar dosing regimens. TRIAL REGISTRATION The study was registered with ClinicalTrials.gov as NCT01755390.

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In order to identify new compounds to treat Chagas disease during the acute phase with higher activity and lower toxicity than the reference drug benznidazole (Bz), two hydroxyphthalazine derivative compounds were prepared and their trypanocidal effects against Trypanosoma cruzi were evaluated by light microscopy through the determination of IC50 values. Cytotoxicity was determined by flow cytometry assays against Vero cells. In vivo assays were performed in BALB/c mice, in which the parasitemia levels were quantified by fresh blood examination; the assignment of a cure was determined by reactivation of blood parasitemia levels after immunosuppression. The mechanism of action was elucidated at metabolic and ultra-structural levels, by (1)H NMR and TEM studies. Finally, as these compounds are potentially capable of causing oxidative damage in the parasites, the study was completed, by assessing their activity as potential iron superoxide dismutase (Fe-SOD) inhibitors. High-selectivity indices observed in vitro were the basis of promoting one of the tested compounds to in vivo assays. The tests on the murine model for the acute phase of Chagas disease showed better parasitemia inhibition values than those found for Bz. Compound 2 induced a remarkable decrease in the reactivation of parasitemia after immunosuppression. Compound 2 turned out to be a great inhibitor of Fe-SOD. The high antiparasitic activity and low toxicity together with the modest costs for the starting materials render this compound an appropriate molecule for the development of an affordable anti-Chagas agent.

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Correct positioning of the tibial component in total knee arthroplasty (TKA) must take into account both an optimal bone coverage (defined by a maximal cortical bearing with posteromedial and anterolateral support) and satisfactory patellofemoral tracking. Consequently, a compromise position must be found by the surgeon during the operation to simultaneously meet these two requirements. Moreover, tibial tray positioning depends upon the tibial torsion, which has been shown to act mainly in the proximal quarter of the tibia. Therefore, the correct application of the tibial tray is also theoretically related to the level of bone resection. In this study, we first quantified the torsional profile given by an optimal bone coverage for a symmetrical tibial tray design and for an asymmetrical one. Then, for the two types of tibial trays, we measured the angle difference between optimal bone coverage and an alignment on the middle of the tibial tubercule. Results showed that the values of the torsional profile given by the symmetrical tray were more scattered than those from the asymmetrical one. However, determination of the mean differential angle between the position providing optimal bone coverage and the one providing the best patellofemoral tracking indicated that the symmetrical prosthetic tray offered the best compromise between these two requirements. Although the tibiofemoral joint is known to be asymmetric in both shape and dimension, the asymmetrical tray chosen in this study was found to fulfill this compromise with more difficulty.