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We characterize a fluxonium qubit consisting of a Josephson junction inductively shunted with a NbTiN nanowire superinductance. We explain the measured energy spectrum by means of a multimode theory accounting for the distributed nature of the superinductance and the effect of the circuit nonlinearity to all orders in the Josephson potential. Using multiphoton Raman spectroscopy, we address multiple fluxonium transitions, observe multilevel Autler-Townes splitting and measure an excited state lifetime of T_{1}=20 µs. By measuring T_{1} at different magnetic flux values, we find a crossover in the lifetime limiting mechanism from capacitive to inductive losses.
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The accomplishment of mature locomotor movements relies upon the integrated coordination of the lower and upper limbs and the trunk. Human adults normally swing their arms and a quadrupedal limb coordination persists during bipedal walking despite a strong corticospinal control of the upper extremities that allows to uncouple this connection during voluntary activities. Here we investigated arm-leg coordination during stepping responses on a surface in human neonates. In eight neonates, we found the overt presence of alternating arm-leg oscillations, the arms moving up and down in alternation with ipsilateral lower limb movements. These neonates moved the diagonal limbs together, and the peak of the arm-to-trunk angle (i.e., maximum vertical excursion of the arm) occurred around the end of the ipsilateral stance phase, as it occurs during typical adult walking. Although episodes of arm-leg coordination were sporadic in our sample of neonates, their presence provides significant evidence for a neural coupling between the upper and lower limbs during early ontogenesis of locomotion in humans.
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Braço/fisiologia , Marcha/fisiologia , Locomoção/fisiologia , Extremidade Inferior/fisiologia , Caminhada/fisiologia , Fenômenos Biomecânicos/fisiologia , Eletromiografia , Feminino , Humanos , Recém-Nascido , Masculino , Músculo Esquelético/fisiologiaRESUMO
AIMS: To evaluate the survival of Mycobacterium avium subsp. paratuberculosis (MAP) during anaerobic digestion (AD), we studied two different biogas plants loaded with manure and slurry from paratuberculosis-infected dairy herds. METHODS AND RESULTS: Both plants were operating under mesophilic conditions, the first with a single digester and the second with a double digester. Mycobacterium avium subsp. paratuberculosis detection was performed by sampling each stage of the process, specifically the prefermenter, fermenter, liquid digestate and solid digestate stages, for 11 months. In both plants, MAP was isolated from the prefermenter stage. Only the final products, the solid and liquid digestates, of the one-stage plant showed viable MAP, while no viable MAP was detected in the digestates of the two-stage plant. CONCLUSIONS: Mycobacterium avium subsp. paratuberculosis showed a significant decrease during subsequent steps of the AD process, particularly in the two-stage plant. We suggest that the second digester maintained the digestate under anaerobic conditions for a longer period of time, thus reducing MAP survival and MAP load under the culture detection limit. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data are unable to exclude the presence of MAP in the final products of the biogas plants, particularly those products from the single digester; therefore, the use of digestates as fertilizers is a real concern related to the possible environmental contamination with MAP.
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Biocombustíveis , Reatores Biológicos/microbiologia , Mycobacterium avium subsp. paratuberculosis/isolamento & purificação , Plantas/metabolismo , Animais , Bovinos , Esterco/microbiologia , Viabilidade Microbiana , Paratuberculose/microbiologiaRESUMO
The aim of the study was to investigate any possible influence of polymorphisms of transmembrane transporters human organic cation transporter 1 (hOCT1), ABCB1, ABCG2 on imatinib pharmacokinetics in 33 men and 27 women (median age and range, 56 and 27-79 years, respectively) affected by chronic myeloid leukemia. A population pharmacokinetic analysis was performed to investigate imatinib disposition in every patient and the role of transporter polymorphisms. Results showed that the α1-acid glycoprotein and the c.480C>G genotype of hOCT1 had a significant effect on apparent drug clearance (CL/F) being responsible, respectively, for a 20% and 10% decrease in interindividual variability (IIV) of CL/F (from 50.1 up to 19.6%). Interestingly, 25 patients carrying at least one polymorphic c.480 G allele had a significant lower CL/F value with respect to the 35 c.480CC individuals (mean±s.d., 9.6±1.6 vs 12.1±2.3 l h(-1), respectively; P<0.001). In conclusion, the hOCT1 c.480C>G SNP may significantly influence imatinib pharmacokinetics, supporting further analyses in larger groups of patients.
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Antineoplásicos/farmacocinética , Benzamidas/farmacocinética , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Transportador 1 de Cátions Orgânicos/genética , Piperazinas/farmacocinética , Polimorfismo de Nucleotídeo Único , Pirimidinas/farmacocinética , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Adulto , Idoso , Benzamidas/uso terapêutico , Feminino , Genótipo , Haplótipos , Humanos , Mesilato de Imatinib , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Piperazinas/uso terapêutico , Pirimidinas/uso terapêuticoRESUMO
Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the one-dimensional Heisenberg model were conjectured as to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we studied the probability distribution of the magnetization transferred across the chain's center, [Formula: see text]. The first two moments of [Formula: see text] show superdiffusive behavior, a hallmark of KPZ universality. However, the third and fourth moments ruled out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide insights into universal behavior in quantum systems.
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Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.
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The ability of vaccine antigen to generate protection is a challenge that cannot be restricted to the antibody response; however, the contribution of T cell-mediated mechanisms has not been extensively analyzed. Age and administration to specific categories of patients, i.e. children with recurrent infections (RI), are some of the factors that might affect the vaccine immune response. We investigated the humoral and cellular response to tetanus toxoid (TT) vaccine in 104 healthy children (HC), 11 newborns and 22 healthy adults to characterize the status of immunity according to age and compared it to 118 RI children. Humoral and cellular responses varied in both groups according to age and doses of TT administered. The prevalence of antibody and cellular response was similar in both cohorts (HC 88 percent and 82 percent versus RI 86 percent and 85 percent), however, TT antibody values were significantly higher in 12-18 months old RI children compared to HC (median: 5 IU/ml vs 1.10 IU/ml) (p = 0.02). The lack of an efficient immune response was observed in 12-15 percent of children from both cohorts. Our data showed that specific antibodies were responsible for early protection, whereas cell-mediated mechanisms may contribute to the generation of long-term immunity after an appropriate vaccine recall. The occurrence of higher TT antibody values in 12-18 months old RI children deserves additional research to determine whether they are caused by different infectious agents and/or by other environmental factors. Clarification of this issue is important for categorizing patients into an optimal vaccine policy.
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Saúde , Imunidade/imunologia , Toxoide Tetânico/imunologia , Tétano/imunologia , Tétano/prevenção & controle , Vacinação , Adulto , Idoso , Anticorpos Antibacterianos/imunologia , Formação de Anticorpos/imunologia , Criança , Citocinas/imunologia , Humanos , Imunidade Celular/imunologia , Imunidade Humoral/imunologia , Lactente , Recém-Nascido , Itália , Pessoa de Meia-Idade , RecidivaRESUMO
Neoadjuvant chemotherapy (NACT) in locally advanced breast tumors may allow an adequate control of the disease impossible with surgery alone. Moreover, NACT increases the chance of breast-conserving surgery. Between 2008 and 2012, we treated with NACT 83 patients with locally advanced breast cancer. We report the preliminary results evaluating the impact of NACT on the type of surgery.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/cirurgia , Mastectomia Segmentar , Terapia Neoadjuvante/métodos , Neoplasias da Mama/patologia , Quimioterapia Adjuvante/métodos , Feminino , Humanos , Estadiamento de Neoplasias , Resultado do TratamentoRESUMO
BACKGROUND: The identification of molecular and genetic markers to predict or monitor the efficacy of bevacizumab (BV) represents a key issue in the treatment of metastatic colorectal cancer (mCRC). METHODS: Plasma levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble VEGF receptor 2 (sVEGFR-2) and thrombospondin-1 (TSP-1) were assessed by ELISA assay at different time points in a cohort of 25 patients enroled in a phase II trial of GONO-FOLFOXIRI plus BV as first-line treatment of mCRC. VEGF: -2578A/C, -1498C/T, -1154A/G, -634C/G and 936C/T; and VEGFR-2: -604A/G, +1192C/T and +1719A/T, polymorphisms were assessed in a total of 54 patients. RESULTS: Treatment with GONO-FOLFOXIRI plus BV determined a prolonged and significant reduction in plasma free, biologically active VEGF concentration. Interestingly, VEGF concentrations remained lower than at baseline also at the time of PD. Conversely, PlGF levels increased during the treatment if compared with baseline, suggesting a possible role in tumour resistance; moreover, sVEGFR-2 increased at the time of PD, as well as TSP-1. No association of assessed polymorphisms with outcome was found. CONCLUSION: Our study suggested the possible mechanisms of resistance to combined therapy in those patients with a progressive disease to be tested in ongoing phase III randomised studies.
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Adenocarcinoma/tratamento farmacológico , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/farmacocinética , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/genética , Neoplasias Colorretais/tratamento farmacológico , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Adulto , Idoso , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais Humanizados , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Bevacizumab , Biomarcadores Tumorais/metabolismo , Camptotecina/administração & dosagem , Camptotecina/efeitos adversos , Camptotecina/análogos & derivados , Camptotecina/farmacocinética , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Esquema de Medicação , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/efeitos adversos , Fluoruracila/farmacocinética , Humanos , Leucovorina/administração & dosagem , Leucovorina/efeitos adversos , Leucovorina/farmacocinética , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Metástase Neoplásica , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Compostos Organoplatínicos/administração & dosagem , Compostos Organoplatínicos/efeitos adversos , Compostos Organoplatínicos/farmacocinética , Farmacogenética , Trombospondina 1/sangue , Trombospondina 1/genética , Fator A de Crescimento do Endotélio Vascular/sangue , Fator A de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/sangue , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genéticaRESUMO
OBJECTIVES: Azathioprine (AZA) is a purine antimetabolite, prodrug widely used as a disease modifying drug in several rheumatic conditions. The aim of the present study was to evaluate the prevalence of TPMT genetic polymorphisms in a cohort of Italian Caucasian patients affected by rheumatic diseases and treated with AZA, and to establish correlations with the tolerability of AZA treatment. RESULTS: Seventy-eight Caucasian patients, 16 males and 62 females, median age 41 years (min-max: 24-76) were enrolled. At the time of evaluation, the median duration of treatment with AZA was 8 months (min-max: 2-150 months); the median dose of AZA per kg of body weight was 1.42 mg (min-max: 0.5-2). Among the 78 patients evaluated, 76 presented a wild type genotype (TPMT *1), while polymorphic alleles were identified in 2 patients (2.6%). Twenty-five patients (32%) experienced different types of adverse events (AE) under AZA treatment. Eighteen patients (23.1%) discontinued AZA because of AE. No correlation was observed between polymorphic TPMT alleles and the development of AE. CONCLUSIONS: Our analysis supports the view that TPMT genotyping alone is not sufficient to adequately personalize the AZA dosage in rheumatic patients. Further studies based on phenotypic analysis of TPMT enzyme and assay of AZA metabolite appear to be required.
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Antimetabólitos/efeitos adversos , Doenças Autoimunes/tratamento farmacológico , Doenças Autoimunes/genética , Azatioprina/efeitos adversos , Metiltransferases/genética , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Antimetabólitos/metabolismo , Azatioprina/metabolismo , Estudos de Coortes , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , População Branca , Adulto JovemRESUMO
Metronomic chemotherapy refers to the administration of chemotherapy at low, nontoxic doses on a frequent schedule with no prolonged breaks. The aim of the study is to rationally develop a CPT-11 metronomic regimen in preclinical settings of colon cancer. In vitro cell proliferation, apoptosis and thrombospondin-1/vascular endothelial growth factor (TSP-1/VEGF) expression analyses were performed on endothelial (HUVEC, HMVEC-d) and colorectal cancer (HT-29, SW620) cells exposed for 144 h to metronomic concentrations of SN-38, the active metabolite of CPT-11. HT-29 human colorectal cancer xenograft model was used, and tumour growth, microvessel density and VEGF/TSP-1 quantification was performed in tumours. In vitro and in vivo combination studies with the tyrosine inhibitor semaxinib were also performed. SN-38 preferentially inhibited endothelial cell proliferation alone and interacted synergistically with semaxinib; it induced apoptosis and increased the expression and secretion of TSP-1. Metronomic CPT-11 alone and combined with semaxinib significantly inhibits tumour growth in the absence of toxicity, which was accompanied by decreases in microvessel density and increases in TSP-1 gene expression in tumour tissues. In vitro results show the antiangiogenic properties of low-concentration SN-38, suggesting a key role of TSP-1 in this effect. In vivo, the CPT-11 metronomic schedule is effective against tumour and microvessel growth without toxic effect on mice.
Assuntos
Inibidores da Angiogênese/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Camptotecina/análogos & derivados , Neoplasias Colorretais/irrigação sanguínea , Neoplasias Colorretais/tratamento farmacológico , Indóis/farmacologia , Pirróis/farmacologia , Inibidores da Angiogênese/administração & dosagem , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Apoptose/efeitos dos fármacos , Camptotecina/administração & dosagem , Camptotecina/farmacologia , Proliferação de Células/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HT29 , Humanos , Técnicas Imunoenzimáticas , Imuno-Histoquímica , Indóis/administração & dosagem , Irinotecano , Masculino , Camundongos , Camundongos Nus , Microcirculação/efeitos dos fármacos , Pirróis/administração & dosagem , Trombospondina 1/efeitos dos fármacos , Trombospondina 1/metabolismo , Transplante Heterólogo , Fator A de Crescimento do Endotélio Vascular/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
The pharmacokinetics (PK) and pharmacodynamics (PD) of metronomic irinotecan have not been studied in cancer patients. The aim of the study is to investigate the PK/PD profile of irinotecan/SN-38 administered by metronomic schedule. Twenty chemotherapy-refractory or chemotherapy-resistant patients with metastatic colorectal carcinoma were enrolled. Irinotecan was infused continuously as follows: irinotecan 1.4 mg m(-2) day(-1) (n=7), 2.8 mg m(-2) day(-1) (n=5) and 4.2 mg m(-2) day(-1) (n=8). Drug levels were examined by HPLC, whereas ELISAs and real-time RT-PCR were used, respectively, for the measurement of plasma levels and gene expression in peripheral blood mononuclear cells of vascular endothelial growth factor/thrombospondin-1. Pharmacokinetic analysis demonstrated that the steady-state levels (C(ss)) of SN-38 were between 1 and 3.3 ng ml(-1). From a PD point of view, higher thrombospondin-1 (TSP-1) plasma levels (153.4+/-30.1 and 130.4+/-9.2% at day 49 vs pretreatment values at 1.4 and 2.8 mg m(-2) day(-1) dose levels, respectively) and increased gene expression in PBMC were found during the metronomic irinotecan infusion, especially at the lower doses. Four patients (20%) obtained a stable disease (median 3.9 months) despite progressing during previous standard irinotecan schedule. Toxicities >grade 1 were not observed. Metronomic irinotecan administration is very well tolerated and induces an increase of gene expression and plasma concentration of TSP-1 at low plasma SN-38 concentrations.
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Antineoplásicos Fitogênicos/farmacocinética , Camptotecina/análogos & derivados , Neoplasias Colorretais/tratamento farmacológico , Idoso , Camptotecina/administração & dosagem , Camptotecina/efeitos adversos , Camptotecina/farmacocinética , Camptotecina/farmacologia , Neoplasias Colorretais/mortalidade , Feminino , Fator Estimulador de Colônias de Granulócitos/farmacologia , Humanos , Irinotecano , Masculino , Pessoa de Meia-Idade , Trombospondina 1/sangue , Trombospondina 1/genética , Fator A de Crescimento do Endotélio Vascular/sangue , Fator A de Crescimento do Endotélio Vascular/genéticaRESUMO
The birth certificate is a valid source of information on pregnancy, birth, the newborn and the parents: such information could be useful to identify and eventually to improve the sanitary, social and economic conditions in which this event takes place and which could have negative effects on pregnancy outcome. In this paper the authors present and analyze the results of a number of births in some sanitary structures in the Umbria region (Italy), carried out through the revision of data reported in the birth certificates during the year 2004.
Assuntos
Declaração de Nascimento , Parto Obstétrico , Gravidez , Feminino , Registros Hospitalares , Humanos , Recém-Nascido , Itália , Resultado da Gravidez , Cuidado Pré-Natal , Sistema de Registros , Estudos Retrospectivos , Fatores de Risco , Fatores SocioeconômicosRESUMO
We report two cases of central nervous system infection due to methicillin-resistant Staphylococcus epidermidis treated with linezolid. The first case was a 72-year old woman with ventriculitis in the presence of intraventricular catheter: therapeutic effectiveness was documented clinically and microbiologically; serum and cerebrospinal fluid levels were measured after the first and fourth doses: trough linezolid concentrations in cerebrospinal fluid were 1.44 and 2.9 mg/L respectively, higher than the minimum inhibitory concentration (MIC). The second case was a 27-year old man with post-traumatic cerebral abscess; during 5 days linezolid was not found in his cerebrospinal fluid despite very high serum level peak, and the drug was not detectable in cerebral tissue surgically removed after 14 days of therapy. Linezolid may not reach therapeutic concentrations in cerebrospinal fluid, and, when possible, we suggest that drug levels be monitored.
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Acetamidas/líquido cefalorraquidiano , Abscesso Encefálico/tratamento farmacológico , Ventrículos Cerebrais , Encefalite/tratamento farmacológico , Resistência a Meticilina , Oxazolidinonas/líquido cefalorraquidiano , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus epidermidis , Adulto , Idoso , Abscesso Encefálico/líquido cefalorraquidiano , Monitoramento de Medicamentos , Encefalite/líquido cefalorraquidiano , Feminino , Humanos , Linezolida , Masculino , Infecções Estafilocócicas/líquido cefalorraquidianoRESUMO
Stepping on ground can be evoked in human neonates, though it is rather irregular and stereotyped heel-to-toe roll-over pattern is lacking. Such investigations can provide insights into the role of contact- or load-related proprioceptive feedback during early development of locomotion. However, the detailed characteristics of foot placements and their association with motor patterns are still incompletely documented. We elicited stepping in 33 neonates supported on a table. Unilateral limb kinematics, bilateral plantar pressure distribution and EMG activity from up to 11 ipsilateral leg muscles were recorded. Foot placement characteristics in neonates showed a wide variation. In ~25% of steps, the swinging foot stepped onto the contralateral foot due to generally small step width. In the remaining steps with separate foot placements, the stance phase could start with forefoot (28%), midfoot (47%), or heel (25%) touchdowns. Despite forefoot or heel initial contacts, the kinematic and loading patterns markedly differed relatively to toe-walking or adult-like two-peaked vertical force profile. Furthermore, while the general stepping parameters (cycle duration, step length, range of motion of proximal joints) were similar, the initial foot contact was consistently associated with specific center-of-pressure excursion, range of motion in the ankle joint, and the center-of-activity of extensor muscles (being shifted by ~5% of cycle toward the end of stance in the "heel" relative to "forefoot" condition). In sum, we found a variety of footfall patterns in conjunction with associated changes in motor patterns. These findings suggest the potential contribution of load-related proprioceptive feedback and/or the expression of variations in the locomotor program already during early manifestations of stepping on ground in human babies.
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[This corrects the article on p. 784 in vol. 8, PMID: 29066982.].
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A growing body of evidence demonstrates the relevant role of the int-2 (FGF-3) oncogene in human carcinomas. To investigate its angiogenic activity, the human epithelial mammary cell line MCF-10A was infected with a retroviral expression vector carrying the int-2 oncogene. Infected cells were entrapped in an alginate pellet and placed on the chorioallantoic membrane of chick embryos. After 7 days, a dense capillary network was found to grow toward the pellet, whereas parental cells did not show any angiogenic activity. Conditioned medium from int-2-infected cells was injected i.p. twice daily into rats over a period of 10 days. The mesentery of treated rats showed numerous small blood vessels originating from larger vascular arcades and growing through the stromal layer of the mesentery. In control experiments, neither medium for cell culture nor conditioned medium from parental cells was found to induce angiogenesis. In conclusion, the stimulation of blood vessel growth by int-2-infected cells suggests that the production of the int-2 protein is associated with the acquisition of the angiogenic phenotype.
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Alantoide/irrigação sanguínea , Córion/irrigação sanguínea , Mesentério/irrigação sanguínea , Neovascularização Patológica/genética , Oncogenes/fisiologia , Proteínas Proto-Oncogênicas/análise , Animais , Neoplasias da Mama/genética , Embrião de Galinha , Proteínas Proto-Oncogênicas/genética , Ratos , Transfecção , Células Tumorais CultivadasRESUMO
PURPOSE: To investigate the sequence effect of irinotecan and a 48-hour infusion of fluorouracil (5-FU) modulated by leucovorin (LV) on the plasma pharmacokinetics of irinotecan and its metabolites, the toxicity profile of this combination, and irinotecan's maximum-tolerated dose (MTD). PATIENTS AND METHODS: Thirty-three metastatic colorectal cancer patients were randomized to receive a 60-minute infusion of irinotecan before or after a 48-hour infusion of 5-FU modulated by LV. The reverse sequence was used after 21 days for the second cycle. 5-FU 3,500 mg/m2 was preceded by l-LV 250 mg/m2. Irinotecan 150 mg/m2 (starting dose) was administered to the first three patients. The dose was escalated by 50 mg/m2 in subsequent groups of three to six patients to determine the MTD for both sequences. Pharmacokinetic analysis of irinotecan and its metabolites was performed after each cycle. RESULTS: Toxicities were affected by the sequence of administration of irinotecan and 5-FU, with an improved tolerability for irinotecan followed by 5-FU. The irinotecan MTD was reached at 300 mg/m2 when irinotecan followed 5-FU and at 450 mg/m2 when it preceded 5-FU. In seven of 23 patients who received both sequences at identical irinotecan doses, the dose-limiting toxicity was observed only when irinotecan followed 5-FU. Pharmacokinetic analysis revealed that the administration sequence significantly affected the SN-38 area under the concentration-versus-time curve (AUC), which was 40.1% lower (P <.05) when irinotecan preceded 5-FU. CONCLUSION: The sequence of treatment with irinotecan and infusional 5-FU affects the tolerability of this combination. This can be explained in part by a reduced SN-38 AUC when irinotecan preceded infusional 5-FU. Well-defined 5-FU/irinotecan regimens are needed because the administration sequence or the interval between the agents might affect treatment tolerance and perhaps also activity.
Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Camptotecina/farmacocinética , Neoplasias Colorretais/tratamento farmacológico , Fluoruracila/farmacologia , Adenocarcinoma/metabolismo , Adulto , Idoso , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/efeitos adversos , Antineoplásicos Fitogênicos/farmacocinética , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Camptotecina/administração & dosagem , Camptotecina/efeitos adversos , Camptotecina/análogos & derivados , Neoplasias Colorretais/metabolismo , Esquema de Medicação , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/efeitos adversos , Inibidores Enzimáticos/farmacocinética , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/efeitos adversos , Humanos , Infusões Intravenosas , Irinotecano , Leucovorina/administração & dosagem , Leucovorina/efeitos adversos , Masculino , Pessoa de Meia-Idade , Metástase NeoplásicaRESUMO
Cellular responses to anti-cancer agents result from the interaction between drugs, cellular targets and mechanisms of damage repair. Despite the pharmacological advances in the treatment of cancer, the clinical efficacy of chemotherapy is unpredictable in most patients. However, new information on the genetics of cancer delineates strategies by which the genetic background of tumour cells and patients might be profiled to select anti-cancer agents with improved efficacy and tolerability. This article focuses on the application of pharmacogenetics in the characterization of differences in the pharmacokinetics and pharmacodynamics of anti-cancer agents among individuals to define the likelihood of response and reduce the incidence of adverse effects.
Assuntos
Antineoplásicos , Neoplasias/genética , Farmacogenética , Antineoplásicos/efeitos adversos , Antineoplásicos/metabolismo , Antineoplásicos/farmacocinética , Antineoplásicos/uso terapêutico , Humanos , Neoplasias/tratamento farmacológico , Polimorfismo GenéticoRESUMO
The aim of this study was to investigate the clinical pharmacokinetics of 5-fluorouracil (5-FU) and its major metabolite 5-fluoro-5,6-dihydrouracil (5-FDHU) in 20 colorectal cancer patients given two dose levels of 5-FU, 250 and 370 mg/m2, administered by i.v. bolus. A reverse-phase high-performance liquid chromatographic method was used for the simultaneous assay of 5-FU and 5-FDHU in plasma samples obtained at baseline and at multiple time points from 5 min to 4 h after 5-FU bolus as well as to assess the activity of dihydropyrimidine dehydrogenase (DPD) in peripheral blood mononuclear cells (PBMCs) before 5-FU dosing. Plasma pharmacokinetic parameters of patients given 250 mg/m2 5-FU were significantly different from those receiving 370 mg/m2; main differences were observed in the trapezoidal areas under the plasma levels-versus-time curve from to to the last measurable concentration (area under the curve, 3.77+/-0.21 versus 13.61+/-2.3 h x microg/ml), peak plasma concentration (Cmax, 18.15+/-1.35 versus 48.41+/-7.69 microg/ml), and total body clearance (CL(TB), 54.64+/-3.54 versus 25.43+/-2.3 l/h/m2). Significant differences were also observed in the main pharmacokinetic parameters of 5-FDHU after 250 and 370 mg/m2 5-FU including the area under the curve from to to 4 h (5.39+/-0.32 versus 8.75+/-1.24 h x microg/ml), Cmax (3.60+/-0.16 versus 5.26+/-0.55 microg/ml) and time to Cmax (Tmax, 0.45+/-0.03 versus 0.69+/-0.06 h). The mean DPD activity in PBMCs in this group of patients was 205.7+/-36.4 pmol of 5-FDHU/min/mg of protein and was within the normal range; however, no significant correlations were found between 5-FU or 5-FDHU pharmacokinetic parameters at two dose levels and DPD activity of PBMCs. The results of the present study provide the first detailed comparison of the distribution of 5-FU and its major metabolite 5-FDHU at the therapeutic level as well as at reduced test dose levels to obtain pharmacokinetic data to be used as reference values for the identification of patients at risk of major 5-FU toxicity due to impaired metabolism to 5-FDHU.