181 resultados para Phase Transformation
Resumo:
Smectite formation in alkaline-saline environments has been attributed to direct precipitation from solution and/or transformation from precursor minerals, but these mechanisms are not universally agreed upon in the literature. The objective of this work was to investigate the mineralogy of smectites in the soils surrounding a representative alkaline-saline lake of Nhecolandia, a sub-region of the Pantanal wetland, Brazil, and then to identify the mechanisms of their formation. Soils were sampled along a toposequence and analyzed by X-ray diffraction, transmission electron microscopy-energy dispersive X-ray analysis, and inductively coupled plasma-mass spectrometry. Water was collected along a transect involving the studied toposequence and equilibrium diagrams were calculated using the databases PHREEQC and AQUA. The fine-clay fraction is dominated by smectite, mica, and kaolinite. Smectites are concentrated at two places in the toposequence: an upper zone, which includes the soil horizons rarely reached by the lake-level variation; and a lower zone, which includes the surface horizon within the area of seasonal lake-level variation. Within the upper zone, the smectite is dioctahedral, rich in Al and Fe, and is classified as ferribeidellite. This phase is interstratified with mica and vermiculite and has an Fe content similar to that of the mica identified. These characteristics suggest that the ferribeidellite originates from transformation of micas and that vermiculite is an intermediate phase in this transformation. Within the lower zone, smectites are dominantly trioctahedral, Mg-rich, and are saponitic and stevensitic minerals. In addition, samples enriched in these minerals have much smaller rare-earth element (REE) contents than other soil samples. The water chemistry shows a geochemical control of Mg and saturation with respect to Mg-smectites in the more saline waters. The REE contents, water chemistry, and the presence of Mg-smectite where maximum evaporation is expected, suggest that saponitic and stevensitic minerals originate by chemical precipitation from the water column of the alkaline-saline lake.
Resumo:
DNA-hsp65, a DNA vaccine encoding the 65-kDa heat-shock protein of Mycobacterium leprae (Hsp65) is capable of inducing the reduction of established tumors in mouse models. We conducted a phase I clinical trial of DNA-hsp65 in patients with advanced head and neck carcinoma. In this article, we report on the vaccine`s potential to induce immune responses to Hsp65 and to its human homologue, Hsp60, in these patients. Twenty-one patients with unresectable squamous cell carcinoma of the head and neck received three doses of 150, 400 or 600 mu g naked DNA-hsp65 plasmid by ultrasound-guided intratumoral injection. Vaccination did not increase levels of circulating anti-hsp65 IgG or IgM antibody, or lead to detectable Hsp65-specific cell proliferation or interferon-gamma (IFN-gamma) production by blood mononuclear cells. Frequency of antigen-induced IL-10-producing cells increased after vaccination in 4 of 13 patients analyzed. Five patients showed disease stability or regression following immunization; however, we were unable to detect significant differences between these patients and those with disease progression using these parameters. There was also no increase in antibody or IFN-gamma responses to human Hsp60 in these patients. Our results suggest that although DNA-hsp65 was able to induce some degree of immunostimulation with no evidence of pathological autoimmunity, we were unable to differentiate between patients with different clinical outcomes based on the parameters measured. Future studies should focus on characterizing more reliable correlations between immune response parameters and clinical outcome that may be used as predictors of vaccine success in immunosuppressed individuals. Cancer Gene Therapy (2009) 16, 598-608; doi:10.1038/cgt.2009.9; published online 6 February 2009
Resumo:
Considering that mycobacterial heat-shock protein 65 (hsp65) gene transfer can elicit a profound antitumoral effect, this study aimed to establish the safety, maximum-tolerated dose (MTD) and preliminary efficacy of DNA-hsp65 immunotherapy in patients with advanced head and neck squamous cell carcinoma (HNSCC). For this purpose, 21 patients with unresectable and recurrent HNSCC were studied. Each patient received three ultrasound-guided injections at 21-day intervals of: 150, 600 or 400 mu g of DNA-hsp65. Toxicity was graded according to CTCAE directions. Tumor volume was measured before and after treatment using computed tomography scan. The evaluation included tumor mass variation, delayed-type hypersensitivity response and spontaneous peripheral blood mononuclear cell proliferation before and after treatment. The MTD was 400 mg per dose. DNA-hsp65 immunotherapy was well tolerated with moderate pain, edema and infections as the most frequent adverse effects. None of the patients showed clinical or laboratory alterations compatible with autoimmune reactions. Partial response was observed in 4 out of 14 patients who completed treatment, 2 of which are still alive more than 3 years after the completion of the trial. Therefore, DNA-hsp65 immunotherapy is a feasible and safe approach at the dose of 400 mg per injection in patients with HNSCC refractory to standard treatment. Further studies in a larger number of patients are needed to confirm the efficacy of this novel strategy.
Resumo:
Purpose Dasatinib is a BCR-ABL inhibitor, 325-fold more potent than imatinib against unmutated BCR-ABL in vitro. Phase II studies have demonstrated efficacy and safety with dasatinib 70 mg twice daily in chronic-phase (CP) chronic myelogenous leukemia (CML) after imatinib treatment failure. In phase I, responses occurred with once-daily administration despite only intermittent BCR-ABL inhibition. Once-daily treatment resulted in less toxicity, suggesting that toxicity results from continuous inhibition of unintended targets. Here, a dose-and schedule-optimization study is reported. Patients and Methods In this open-label phase III trial, 670 patients with imatinib-resistant or -intolerant CP-CML were randomly assigned 1: 1: 1: 1 between four dasatinib treatment groups: 100 mg once daily, 50 mg twice daily, 140 mg once daily, or 70 mg twice daily. Results With minimum follow-up of 6 months (median treatment duration, 8 months; range, = 1 to 15 months), marked and comparable hematologic (complete, 86% to 92%) and cytogenetic (major, 54% to 59%; complete, 41% to 45%) response rates were observed across the four groups. Time to and duration of cytogenetic response were similar, as was progression-free survival (8% to 11% of patients experienced disease progression or died). Compared with the approved 70-mg twice-daily regimen, dasatinib 100 mg once daily resulted in significantly lower rates of pleural effusion (all grades, 7% v 16%; P = .024) and grade 3 to 4 thrombocytopenia (22% v 37%; P = .004), and fewer patients required dose interruption (51% v 68%), reduction (30% v 55%), or discontinuation (16% v 23%). Conclusion Dasatinib 100 mg once daily retains the efficacy of 70 mg twice daily with less toxicity. Intermittent target inhibition with tyrosine kinase inhibitors may preserve efficacy and reduce adverse events.
Resumo:
Purpose: Erlotinib, an oral tyrosine kinase inhibitor, is active against head-and-neck squamous cell carcinoma (HNSCC) and possibly has a synergistic interaction with chemotherapy and radiotherapy. We investigated the safety and efficacy of erlotinib added to cisplatin and radiotherapy in locally advanced HNSCC. Methods and Materials: In this Phase I/II trial 100 mg/m(2) of cisplatin was administered on Days 8, 29, and 50, and radiotherapy at 70 Gy was started on Day 8. During Phase I, the erlotinib dose was escalated (50 mg, 100 mg, and 150 mg) in consecutive cohorts of 3 patients, starting on Day 1 and continuing during radiotherapy. Dose-limiting toxicity was defined as any Grade 4 event requiring radiotherapy interruptions. Phase 11 was initiated 8 weeks after the last Phase I enrollment. Results: The study accrued 9 patients in Phase I and 28 in Phase II; all were evaluable for efficacy and safety. No dose-limiting toxicity occurred in Phase I, and the recommended Phase 11 dose was 150 mg. The most frequent nonhematologic toxicities were nausea/vomiting, dysphagia, stomatitis, xerostomia and in-field dermatitis, acneiform rash, and diarrhea. Of the 31 patients receiving a 150-mg daily dose of erlotinib, 23 (74%; 95% confidence interval, 56.8%-86.3%) had a complete response, 3 were disease free after salvage surgery, 4 had inoperable residual disease, and 1 died of sepsis during treatment. With a median 37 months` follow-up, the 3-year progression-free and overall survival rates were 61% and 72%, respectively. Conclusions: This combination appears safe, has encouraging activity, and deserves further studies in locally advanced HNSCC. (C) 2010 Elsevier Inc.
Resumo:
Purpose We investigated the efficacy of fluorouracil (FU), leucovorin, irinotecan, and bevacizumab (FOLFIRI + B) in a phase II trial in patients previously untreated for metastatic colorectal cancer (mCRC), and changes during treatment in plasma cytokines and angiogenic factors (CAFs) as potential markers of treatment response and therapeutic resistance. Patients and Methods We conducted a phase II, two-institution trial of FOLFIRI + B. Each 14-day cycle consisted of bevacizumab (5 mg/kg), irinotecan (180 mg/m(2)), bolus FU (400 mg/m(2)), and leucovorin (400 mg/m(2)) followed by a 46-hour infusion of FU (2,400 mg/m(2)). Levels of 37 CAFs were assessed using multiplex-bead assays and enzyme-linked immunosorbent assay at baseline, during treatment, and at the time of progressive disease (PD). Results Forty-three patients were enrolled. Median progression-free survival (PFS), the primary end point of the study, was 12.8 months. Median overall survival was 31.3 months, with a response rate of 65%. Elevated interleukin-8 at baseline was associated with a shorter PFS (11 v 15.1 months, P = .03). Before the radiographic development of PD, several CAFs associated with angiogenesis and myeloid recruitment increased compared to baseline, including basic fibroblast growth factor (P = .046), hepatocyte growth factor (P = .046), placental growth factor (P < .001), stromal-derived factor-1 (P = .04), and macrophage chemoattractant protein-3 (P < .001). Conclusion Efficacy and tolerability of FOLFIRI + B appeared favorable to historical controls in this single arm study. Before radiographic progression, there was a shift in balance of CAFs, with a rise in alternate pro-angiogenic cytokines and myeloid recruitment factors in subsets of patients that may represent mechanisms of resistance.
Resumo:
Neural phase signaling has gained attention as a putative coding mechanism through which the brain binds the activity of neurons across distributed brain areas to generate thoughts, percepts, and behaviors. Neural phase signaling has been shown to play a role in various cognitive processes, and it has been suggested that altered phase signaling may play a role in mediating the cognitive deficits observed across neuropsychiatric illness. Here, we investigated neural phase signaling in two mouse models of cognitive dysfunction: mice with genetically induced hyperdopaminergia [dopamine transporter knock-out (DAT-KO) mice] and mice with genetically induced NMDA receptor hypofunction [NMDA receptor subunit-1 knockdown (NR1-KD) mice]. Cognitive function in these mice was assessed using a radial-arm maze task, and local field potentials were recorded from dorsal hippocampus and prefrontal cortex as DAT-KO mice, NR1-KD mice, and their littermate controls engaged in behavioral exploration. Our results demonstrate that both DAT-KO and NR1-KD mice display deficits in spatial cognitive performance. Moreover, we show that persistent hyperdopaminergia alters interstructural phase signaling, whereas NMDA receptor hypofunction alters interstructural and intrastructural phase signaling. These results demonstrate that dopamine and NMDA receptor dependent glutamate signaling play a critical role in coordinating neural phase signaling, and encourage further studies to investigate the role that deficits in phase signaling play in mediating cognitive dysfunction.
Resumo:
Purpose: To compare the efficacy and tolerability of the fixed combination of timolol maleate 0.5%/brimonidine tartrate 0.2% versus fixed combination of timolol maleate 0.5%/dorzolamide 2% in patients with elevated intraocular pressure (IOP) over 8 weeks. Patients and Methods: This 8-week, multicentric. interventional, randomized, open-label, parallel group study was conducted Lit 4 centers in Brazil and 1 center in Argentina. Patients with open-angle glaucoma or ocular hypertension were randomized to receive bilaterally fixed combination of brimonidine/timolol maleate 0.5% or fixed combination of dorzolamide 2%/timolol 0.5% twice daily at 8:00 AM and 8:00 PM. A modified diurnal tension curve (8:00 AM 10:30 AM, 02:00 PM, and 4:00 PM) followed by the water drinking test (WDT), which estimates IOP peak of diurnal tension curve, were performed in the baseline and week-8 visits. Adverse events data were recorded at each visit. Results: A total of 210 patients were randomized (brimonidine/timolol, n = 111; dorzolamide/timolol, n = 99). Mean baseline IOP was 23.43 +/- 3.22 mm Hg and 23.43 +/- 4.06 mm Hg in the patients treated with brimonidine/timolol and dorzolamide/timolol, respectively (P = 0.993). Mean diurnal IOP reduction after 8 weeks were 7.02 +/- 3.06 mm Hg and 6.91 +/- 3.67 mm Hg. respectively (P = 0.811). The adjusted difference between groups (analysis of covariance) Lit week 8 was not statistically significant (P = 0.847). Mean baseline WDT peak was 27.79 +/- 4.29 mm Hg in the brimonidine/timolol group and 27.68 +/- 5.46 mm Hg in the dorzolamide/timolol group. After 8 weeks of treatment, mean WDT peaks were 20.94 +/- 3.76 mm Hg (P < 0.001) and 20.98 +/- 4.19 (P < 0.001), respectively. The adjusted difference between groups (analysis of covariance) was not statistically significant (P = 0.469). No statistical difference in terms of adverse events was Found between groups. Conclusions: Both fixed combinations were capable of significantly reducing the mean diurnal IOP, mean diurnal peak, and mean WDT peak after 8 weeks of treatment. Also, both fixed combinations are well tolerated with few side effects.
Resumo:
To investigate the luteal phase endometrial expression of leukemia inhibitor factor (LIF), insulin-like growth factor 1 (IGF-1), progesterone receptor (PR), claudin 4 (CLDN4), vascular-endothelial growth factor receptor 3 (VEGFR-3), bone morphogenetic protein 4 (BMP-4) and citokeratin 7 (CK-7), we obtained luteal phase endometrial samples from 52 women. Samples were dated and integrated using a tissue microarray (TMA). Samples were immunostained for LIF, IGF-1, PR, CLDN4, VEGFR-3, BMP-4 and CK-7. Frequencies of positive expressions at the early, mid and late luteal phases were compared by two proportions test. Concomitant expression of these proteins was assessed with Chi-square or Fischer`s test. The frequency of LIF was positively correlated to the frequency of IGF-1 (r = 0.99; p < 0.05) and PR (r = 0.99; p < 0.05), and the correlation between IGF-1 and PR tended to be significant (r = 0.98; p < 0.1). The expression of PR was associated with the absence of CLDN4 (p < 0.001). Thus, expression of LIF, IGF-1 and PR are correlated during the luteal phase, and immunohistochemistry for these proteins might be used to assist in the assessment of endometrial maturation. In addition, the expression of CLDN4 and PR was not concomitant, warranting further investigation on the relationship of their endometrial expression.
Resumo:
Background: Attention deficit hyperactivity disorder (ADHD) is a clinically significant disorder in adulthood, but current diagnostic criteria and instruments do not seem to adequately capture the complexity of the disorder in this developmental phase. Accordingly, there are limited data on the proportion of adults affected by the disorder, specially in developing countries. Method: We assessed a representative household sample of the Brazilian population for ADHD with the Adult ADHD Self-report Scale (ASRS) Screener, and evaluated the instrument according to the Rasch model of item response theory. Results: The sample was comprised by 3007 individuals, and the overal prevalence of positive screeners for ADHD was 5.8% [95% confidence interval (CI), 4.8-7.0]. Rasch analyses revealed the misfitt of the overall sample to expectations of the model. The evaluation of the sample stratified by age revealed that data for adolescents showed a signficant fittnes to the model expectations, while items completed by adults were not adequated. Conclusions: The lack of fitness to the model for adult respondents challenges the possibility of a linear transformation of the ordinal data into interval measures and the utilization of parametric analyses of data. This result suggests that diagnostic criteria and instruments for adult ADHD must take into account a developmental perspective. Moreover, it calls for further evaluation of currently employed research methods in light of modern theories of psychometrics. Copyright (C) 2010 John Wiley & Sons, Ltd.
Resumo:
Oral treatment with phosphodiesterase type 5 inhibitor (PDE5) is considered the first-line treatment for patients with erectile dysfunction (ED). Lodenafil carbonate (LC) is a novel PDE5. This is a phase II, prospective, randomized, double-blind, and placebo controlled clinical trial of LC. Efficacy end points were International Index of Sexual Function (IIEF) erectile domain, IIEF questions 3 and 4, and Sexual Encounter Profile (SEP) questions 2 and 3, before and after the use of LC or placebo. Seventy-two men older than 18 years, with ED for at least 6 months with stable sexual relationship were enrolled. Patients were randomized to placebo or LC 80 mg, 40 mg, or 20 mg and followed for 4 weeks. IIEF erectile domain scores before and after the use of medications were (mean +/- standard deviation [SD]): placebo: 11.9 +/- 3.4 and 12.6 +/- 5.5; LC 20 mg: 15.8 +/- 4.1 and 18.9 +/- 6.6; LC 40 mg: 11.9 +/- 4.4 and 15.4 +/- 8.1; LC 80 mg: 14.2 +/- 4.7 and 22.8 +/- 6.0 (anova P < 0.01). The SEP-2 scores before and after the use of medications were (Mean +/- SD): placebo: 71.0 +/- 33.1 and 51.2 +/- 43.1; LC 20 mg 70.3 +/- 34.2 and 75.5 +/- 31.5; LC 40 mg: 48.4 +/- 42.1 and 60.8 +/- 42.5; LC 80 mg: 68.6 +/- 33.5 and 89.6 +/- 26.0. The SEP-3 scores were: placebo 23.3 +/- 27.6 and 33.6 +/- 42.3; LC 20 mg: 32.3 +/- 38.9 and 51.2 +/- 41.7; LC 40 mg: 39.7 +/- 44.7 and 46.7 +/- 41.1; LC 80 mg* 17.2 +/- 29.5 and 74.3 +/- 36.4 (*P < 0.05 for difference to placebo). The drug was well tolerated. Adverse reactions were mild and self-limited and included headache, rhinitis, flushing, color visual disorders, and dyspepsia. This study showed that the dosage of 80 mg of LC was significantly more efficacious than placebo and well tolerated. Glina S, Toscano I, Gomatzky C, de Goes PM, Junior AN, de Almeida Claro JF, and Pagani E. Efficacy and tolerability of lodenafil carbonate for oral therapy in erectile dysfunction: A phase II clinical trial. J Sex Med 2009;6:553-557.
Resumo:
Prolonged infusions have been shown to be safer and potentially more effective than bolus regimens of 5-fluorouracil (5-FU) as treatment for metastatic colorectal cancer (mCRC). However, infusional 5-FU requires central venous access and costly infusion pumps. Oral fluoropyrimidines enable longer exposures to 5-FU with increased convenience. Tegafur - uracil (UFT) with leucovorin (LV) given thrice daily has improved safety plus comparable survival and response rates to bolus 5-FU/LV. We conducted a phase II clinical study in 98 patients with mCRC to evaluate if UFT with LV given twice daily provided comparable time to progression ( TTP), efficacy and tolerability to that reported for thrice daily in two phase III clinical studies. Secondary objectives included overall response rate ( ORR) and overall survival ( OS). Median TTP was 3.8 months, when compared with 3.5 months for thrice daily. The ORR ( 11%) and median OS ( 12.8 months) with twice daily administration were similar to that of thrice daily administration ( 12% and 12.4 months). The incidence of grade 3/4 treatment-related diarrhoea was 30% on the twice daily and 21% on the thrice daily schedule. These results suggest that twice daily administration has similar efficacy and tolerability to thrice daily administration and is an acceptable alternative for patients who would benefit from UFT with LV therapy.
Resumo:
Background Changes in the shape of the capnogram may reflect changes in lung physiology. We studied the effect of different ventilation/perfusion ratios (V/Q) induced by positive end-expiratory pressures (PEEP) and lung recruitment on phase III slope (S(III)) of volumetric capnograms. Methods Seven lung-lavaged pigs received volume control ventilation at tidal volumes of 6 ml/kg. After a lung recruitment maneuver, open-lung PEEP (OL-PEEP) was defined at 2 cmH(2)O above the PEEP at the onset of lung collapse as identified by the maximum respiratory compliance during a decremental PEEP trial. Thereafter, six distinct PEEP levels either at OL-PEEP, 4 cmH(2)O above or below this level were applied in a random order, either with or without a prior lung recruitment maneuver. Ventilation-perfusion distribution (using multiple inert gas elimination technique), hemodynamics, blood gases and volumetric capnography data were recorded at the end of each condition (minute 40). Results S(III) showed the lowest value whenever lung recruitment and OL-PEEP were jointly applied and was associated with the lowest dispersion of ventilation and perfusion (Disp(R-E)), the lowest ratio of alveolar dead space to alveolar tidal volume (VD(alv)/VT(alv)) and the lowest difference between arterial and end-tidal pCO(2) (Pa-ETCO(2)). Spearman`s rank correlations between S(III) and Disp(R-E) showed a =0.85 with 95% CI for (Fisher`s Z-transformation) of 0.74-0.91, P < 0.0001. Conclusion In this experimental model of lung injury, changes in the phase III slope of the capnograms were directly correlated with the degree of ventilation/perfusion dispersion.
Resumo:
Tick bites may trigger acute phase responses. Positive and negative acute phase proteins were measured in infested cattle genetically resistant and susceptible to ticks. During heavier infestations levels of haptoglobin increased significantly in susceptible bovines; levels of serum amyloid A increased in resistant bovines; levels of alpha-l-acid glycoprotein decreased significantly in resistant bovines; levels of transferrin decreased significantly in susceptible bovines. In conclusion, tick infestations trigger acute phase responses and enhancement of specific acute phase proteins differs according to the genetic composition of hosts. Acute phase proteins may constitute useful biological signatures for monitoring the stress induced by tick infestations. (c) 2007 Elsevier Inc. All rights reserved.
Resumo:
Diphenism in social bees is essentially contingent on nutrient-induced cellular and systemic physiological responses resulting in divergent gene expression patterns. Analyses of juvenile hormone (JH) titers and functional genomics assays of the insulin-insulin-like signaling (IIS) pathway and its associated branch, target-of-rapamycin (TOR), revealed systemic responses underlying honey bee (Apis mellifera) caste development. Nevertheless, little attention has been paid to cellular metabolic responses. Following up earlier investigations showing major caste differences in oxidative metabolism and mitochondrial physiology, we herein identified honey bee homologs of hypoxia signaling factors, HIF alpha/Sima, HIF beta/Tango and PHD/Fatiga and we investigated their transcript levels throughout critical stages of larval development. Amsima, Amtango and Amfatiga showed correlated transcriptional activity, with two peaks of occurring in both queens and workers, the first one shortly after the last larval molt and the second during the cocoon-spinning phase. Transcript levels for the three genes were consistently higher in workers. As there is no evidence for major microenvironmental differences in oxygen levels within the brood nest area, this appears to be an inherent caste character. Quantitative PCR analyses on worker brain, ovary, and leg imaginal discs showed that these tissues differ in transcript levels. Being a highly conserved pathway and linked to IIS/TOR, the hypoxia gene expression pattern seen in honey bee larvae denotes that the hypoxia pathway has undergone a transformation, at least during larval development, from a response to environmental oxygen concentrations to an endogenous regulatory factor in the diphenic development of honey bee larvae. (C) 2010 Elsevier Ltd. All rights reserved.