995 resultados para Medical Subject Headings::Chemicals and Drugs::Organic Chemicals::Amines::Catecholamines::Dopamine
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In their safety evaluations of bisphenol A (BPA), the U.S. Food and Drug Administration (FDA) and a counterpart in Europe, the European Food Safety Authority (EFSA), have given special prominence to two industry-funded studies that adhered to standards defined by Good Laboratory Practices (GLP). These same agencies have given much less weight in risk assessments to a large number of independently replicated non-GLP studies conducted with government funding by the leading experts in various fields of science from around the world. OBJECTIVES: We reviewed differences between industry-funded GLP studies of BPA conducted by commercial laboratories for regulatory purposes and non-GLP studies conducted in academic and government laboratories to identify hazards and molecular mechanisms mediating adverse effects. We examined the methods and results in the GLP studies that were pivotal in the draft decision of the U.S. FDA declaring BPA safe in relation to findings from studies that were competitive for U.S. National Institutes of Health (NIH) funding, peer-reviewed for publication in leading journals, subject to independent replication, but rejected by the U.S. FDA for regulatory purposes. DISCUSSION: Although the U.S. FDA and EFSA have deemed two industry-funded GLP studies of BPA to be superior to hundreds of studies funded by the U.S. NIH and NIH counterparts in other countries, the GLP studies on which the agencies based their decisions have serious conceptual and methodologic flaws. In addition, the U.S. FDA and EFSA have mistakenly assumed that GLP yields valid and reliable scientific findings (i.e., "good science"). Their rationale for favoring GLP studies over hundreds of publically funded studies ignores the central factor in determining the reliability and validity of scientific findings, namely, independent replication, and use of the most appropriate and sensitive state-of-the-art assays, neither of which is an expectation of industry-funded GLP research. CONCLUSIONS: Public health decisions should be based on studies using appropriate protocols with appropriate controls and the most sensitive assays, not GLP. Relevant NIH-funded research using state-of-the-art techniques should play a prominent role in safety evaluations of chemicals.
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BACKGROUND. Either higher levels of initial DNA damage or lower levels of radiation-induced apoptosis in peripheral blood lymphocytes have been associated to increased risk for develop late radiation-induced toxicity. It has been recently published that these two predictive tests are inversely related. The aim of the present study was to investigate the combined role of both tests in relation to clinical radiation-induced toxicity in a set of breast cancer patients treated with high dose hyperfractionated radical radiotherapy. METHODS. Peripheral blood lymphocytes were taken from 26 consecutive patients with locally advanced breast carcinoma treated with high-dose hyperfractioned radical radiotherapy. Acute and late cutaneous and subcutaneous toxicity was evaluated using the Radiation Therapy Oncology Group morbidity scoring schema. The mean follow-up of survivors (n = 13) was 197.23 months. Radiosensitivity of lymphocytes was quantified as the initial number of DNA double-strand breaks induced per Gy and per DNA unit (200 Mbp). Radiation-induced apoptosis (RIA) at 1, 2 and 8 Gy was measured by flow cytometry using annexin V/propidium iodide. RESULTS. Mean DSB/Gy/DNA unit obtained was 1.70 ± 0.83 (range 0.63-4.08; median, 1.46). Radiation-induced apoptosis increased with radiation dose (median 12.36, 17.79 and 24.83 for 1, 2, and 8 Gy respectively). We observed that those "expected resistant patients" (DSB values lower than 1.78 DSB/Gy per 200 Mbp and RIA values over 9.58, 14.40 or 24.83 for 1, 2 and 8 Gy respectively) were at low risk of suffer severe subcutaneous late toxicity (HR 0.223, 95%CI 0.073-0.678, P = 0.008; HR 0.206, 95%CI 0.063-0.677, P = 0.009; HR 0.239, 95%CI 0.062-0.929, P = 0.039, for RIA at 1, 2 and 8 Gy respectively) in multivariate analysis. CONCLUSIONS. A radiation-resistant profile is proposed, where those patients who presented lower levels of initial DNA damage and higher levels of radiation induced apoptosis were at low risk of suffer severe subcutaneous late toxicity after clinical treatment at high radiation doses in our series. However, due to the small sample size, other prospective studies with higher number of patients are needed to validate these results.
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ATM and PARP-1 are two of the most important players in the cell's response to DNA damage. PARP-1 and ATM recognize and bound to both single and double strand DNA breaks in response to different triggers. Here we report that ATM and PARP-1 form a molecular complex in vivo in undamaged cells and this association increases after gamma-irradiation. ATM is also modified by PARP-1 during DNA damage. We have also evaluated the impact of PARP-1 absence or inhibition on ATM-kinase activity and have found that while PARP-1 deficient cells display a defective ATM-kinase activity and reduced gamma-H2AX foci formation in response to gamma-irradiation, PARP inhibition on itself is able to activate ATM-kinase. PARP inhibition induced gamma H2AX foci accumulation, in an ATM-dependent manner. Inhibition of PARP also induces DNA double strand breaks which were dependent on the presence of ATM. As consequence ATM deficient cells display an increased sensitivity to PARP inhibition. In summary our results show that while PARP-1 is needed in the response of ATM to gamma irradiation, the inhibition of PARP induces DNA double strand breaks (which are resolved in and ATM-dependent pathway) and activates ATM kinase.
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Caveolae are involved in physical compartmentalization between different groups of signaling events. Its main component, CAV1, modulates different pathways in cellular physiology. The emerging evidence pointing to the role of CAV1 in cancer led us to study whether different alleles of this gene are associated with colorectal cancer (CRC). Since one of the most characterized enzymes regulated by CAV1 is eNOS, we decided to include both genes in this study. We analyzed five SNPs in 360 unrelated CRC patients and 550 controls from the general population. Two of these SNPs were located within eNOS and three within the CAV1 gene. Although haplotype distribution was not associated with CRC, haplotype TiA (CAV1) was associated with familiar forms of CRC (p<0.05). This was especially evident in CRC antecedents and nuclear forms of CRC. If both CG (eNOS) and TiA (CAV1) haplotypes were taken together, this association increased in significance. Thus, we propose that CAV1, either alone or together with eNOS alleles, might modify CRC heritability.
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INTRODUCTION Human host immune response following infection with the new variant of A/H1N1 pandemic influenza virus (nvH1N1) is poorly understood. We utilize here systemic cytokine and antibody levels in evaluating differences in early immune response in both mild and severe patients infected with nvH1N1. METHODS We profiled 29 cytokines and chemokines and evaluated the haemagglutination inhibition activity as quantitative and qualitative measurements of host immune responses in serum obtained during the first five days after symptoms onset, in two cohorts of nvH1N1 infected patients. Severe patients required hospitalization (n = 20), due to respiratory insufficiency (10 of them were admitted to the intensive care unit), while mild patients had exclusively flu-like symptoms (n = 15). A group of healthy donors was included as control (n = 15). Differences in levels of mediators between groups were assessed by using the non parametric U-Mann Whitney test. Association between variables was determined by calculating the Spearman correlation coefficient. Viral load was performed in serum by using real-time PCR targeting the neuraminidase gene. RESULTS Increased levels of innate-immunity mediators (IP-10, MCP-1, MIP-1beta), and the absence of anti-nvH1N1 antibodies, characterized the early response to nvH1N1 infection in both hospitalized and mild patients. High systemic levels of type-II interferon (IFN-gamma) and also of a group of mediators involved in the development of T-helper 17 (IL-8, IL-9, IL-17, IL-6) and T-helper 1 (TNF-alpha, IL-15, IL-12p70) responses were exclusively found in hospitalized patients. IL-15, IL-12p70, IL-6 constituted a hallmark of critical illness in our study. A significant inverse association was found between IL-6, IL-8 and PaO2 in critical patients. CONCLUSIONS While infection with the nvH1N1 induces a typical innate response in both mild and severe patients, severe disease with respiratory involvement is characterized by early secretion of Th17 and Th1 cytokines usually associated with cell mediated immunity but also commonly linked to the pathogenesis of autoimmune/inflammatory diseases. The exact role of Th1 and Th17 mediators in the evolution of nvH1N1 mild and severe disease merits further investigation as to the detrimental or beneficial role these cytokines play in severe illness.
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BACKGROUND
Recent advances in characterizing the immune recovery of HIV-1-infected people have highlighted the importance of the thymus for peripheral T-cell diversity and function. The aim of this study was to investigate differences in immune reconstitution profiles after highly active antiretroviral therapy (HAART) between HIV-children and adults.
METHODS
HIV patients were grouped according to their previous clinical and immunological status: 9 HIV-Reconstituting-adults (HIV-Rec-adults) and 10 HIV-Reconstituting-children (HIV-Rec-children) on HAART with viral load (VL)
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BACKGROUND The randomized placebo-controlled IFIGENIA-trial demonstrated that therapy with high-dose N-acetylcysteine (NAC) given for one year, added to prednisone and azathioprine, significantly ameliorates (i.e. slows down) disease progression in terms of vital capacity (VC) (+9%) and diffusing capacity (DLco) (+24%) in idiopathic pulmonary fibrosis (IPF). To better understand the clinical implications of these findings we performed additional, explorative analyses of the IFGENIA data set. METHODS We analysed effects of NAC on VC, DLco, a composite physiologic index (CPI), and mortality in the 155 study-patients. RESULTS In trial completers the functional indices did not change significantly with NAC, whereas most indices deteriorated with placebo; in non-completers the majority of indices worsened but decline was generally less pronounced in most indices with NAC than with placebo. Most categorical analyses of VC, DLco and CPI also showed favourable changes with NAC. The effects of NAC on VC, DLco and CPI were significantly better if the baseline CPI was 50 points or lower. CONCLUSION This descriptive analysis confirms and extends the favourable effects of NAC on lung function in IPF and emphasizes the usefulness of VC, DLco, and the CPI for the evaluation of a therapeutic effect. Most importantly, less progressed disease as indicated by a CPI of 50 points or lower at baseline was more responsive to therapy in this study.
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Bacillary angiomatosis is a recently described infectious disease that usually affects immunosupressed hosts with a previous history of contact with cats. We report a rare case of bacillary angiomatosis in an immunocompetent 59-year-old woman with no history of previous exposure to cats, and atypical clinical features (fever and subcutaneous nodules with ulceration on the left ankle). Histopathology of the lesion showed extensive ulceration and reactive tumor-like vascular proliferation of the blood vessels with swollen endothelial cells and an inflammatory infiltrate including neutrophils and lymphocytes in the dermis and subcutis. Staining with the Warthin-Starry method demonstrated the presence of clustered bacilli located in the extracellular matrix adjacent to the proliferating endothelial cells. Diagnosis was confirmed with the detection of Bartonella spp. DNA in the affected skin and in bone marrow using polymerase chain reaction.
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Androgen-sensitive prostate cancer cells turn androgen resistant through complex mechanisms that involve dysregulation of apoptosis. We investigated the role of antiapoptotic Bcl-xL in the progression of prostate cancer as well as the interactions of Bcl-xL with proapoptotic Bax and Bak in androgen-dependent and -independent prostate cancer cells. Immunohistochemical analysis was used to study the expression of Bcl-xL in a series of 139 prostate carcinomas and its association with Gleason grade and time to hormone resistance. Expression of Bcl-xL was more abundant in prostate carcinomas of higher Gleason grades and significantly associated with the onset of hormone-refractory disease. In vivo interactions of Bcl-xL with Bax or Bak in untreated and camptothecin-treated LNCaP and PC3 cells were investigated by means of coimmunoprecipitation. In the absence of any stimuli, Bcl-xL interacts with Bax and Bak in androgen-independent PC3 cells but only with Bak in androgen-dependent LNCaP cells. Interactions of Bcl-xL with Bax and Bak were also evidenced in lysates from high-grade prostate cancer tissues. In LNCaP cells treated with camptothecin, an inhibitor of topoisomerase I, the interaction between Bcl-xL and Bak was absent after 36 h, Bcl-xL decreased gradually and Bak increased coincidentally with the progress of apoptosis. These results support a model in which Bcl-xL would exert an inhibitory effect over Bak via heterodimerization. We propose that these interactions may provide mechanisms for suppressing the activity of proapoptotic Bax and Bak in prostate cancer cells and that Bcl-xL expression contributes to androgen resistance and progression of prostate cancer.
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Hemeoxygenase-2 (HO-2) is an antioxidant enzyme that can modulate recombinant maxi-K(+) channels and has been proposed to be the acute O(2) sensor in the carotid body (CB). We have tested the physiological contribution of this enzyme to O(2) sensing using HO-2 null mice. HO-2 deficiency leads to a CB phenotype characterized by organ growth and alteration in the expression of stress-dependent genes, including the maxi-K(+) channel alpha-subunit. However, sensitivity to hypoxia of CB is remarkably similar in HO-2 null animals and their control littermates. Moreover, the response to hypoxia in mouse and rat CB cells was maintained after blockade of maxi-K(+) channels with iberiotoxin. Hypoxia responsiveness of the adrenal medulla (AM) (another acutely responding O(2)-sensitive organ) was also unaltered by HO-2 deficiency. Our data suggest that redox disregulation resulting from HO-2 deficiency affects maxi-K(+) channel gene expression but it does not alter the intrinsic O(2) sensitivity of CB or AM cells. Therefore, HO-2 is not a universally used acute O(2) sensor.
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BACKGROUND ErbB2-positive breast cancer is characterized by highly aggressive phenotypes and reduced responsiveness to standard therapies. Although specific ErbB2-targeted therapies have been designed, only a small percentage of patients respond to these treatments and most of them eventually relapse. The existence of this population of particularly aggressive and non-responding or relapsing patients urges the search for novel therapies. The purpose of this study was to determine whether cannabinoids might constitute a new therapeutic tool for the treatment of ErbB2-positive breast tumors. We analyzed their antitumor potential in a well established and clinically relevant model of ErbB2-driven metastatic breast cancer: the MMTV-neu mouse. We also analyzed the expression of cannabinoid targets in a series of 87 human breast tumors. RESULTS Our results show that both Delta9-tetrahydrocannabinol, the most abundant and potent cannabinoid in marijuana, and JWH-133, a non-psychotropic CB2 receptor-selective agonist, reduce tumor growth, tumor number, and the amount/severity of lung metastases in MMTV-neu mice. Histological analyses of the tumors revealed that cannabinoids inhibit cancer cell proliferation, induce cancer cell apoptosis, and impair tumor angiogenesis. Cannabinoid antitumoral action relies, at least partially, on the inhibition of the pro-tumorigenic Akt pathway. We also found that 91% of ErbB2-positive tumors express the non-psychotropic cannabinoid receptor CB2. CONCLUSIONS Taken together, these results provide a strong preclinical evidence for the use of cannabinoid-based therapies for the management of ErbB2-positive breast cancer.
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High postprandial levels of TAG may further induce endothelial dysfunction and inflammation in subjects with high fasting levels of TAG, an effect that seems to be related to oxidative stress. The present study investigated whether minor compounds of olive oil with antioxidant activity decrease postprandial levels of soluble isoforms of intercellular adhesion molecule 1 (sICAM-1) and vascular cell adhesion molecule 1 (sVCAM-1), as surrogate markers of vascular inflammation, after a high-fat meal. A randomized crossover and blind trial on fourteen healthy and fourteen hypertriacylglycerolaemic subjects was performed. The study involved a 1-week adaptation lead-in period on a National Cholesterol Education Program Step I diet supplemented with extra-virgin olive oil (EVOO) containing 1125 mg polyphenols/kg and 350 mg tocopherols/kg, or refined olive oil (ROO) with no polyphenols or tocopherols. After a 12 h fast, the participants ate a high-fat meal enriched in EVOO or ROO (50 g/m2 body surface area), which on average provided 3700 kJ energy with a macronutrient profile of 72% fat, 22% carbohydrate and 6% protein. Blood samples drawn hourly over the following 8 h demonstrated a similar postprandial TAG response for both EVOO and ROO meals. However, in both healthy and hypertriacylglycerolaemic subjects the net incremental area under the curve for sICAM-1 and sVCAM-1 were significantly lower after the EVOO meal. In conclusion,the consumption of EVOO with a high content of minor antioxidant compounds may have postprandial anti-inflammatory protective effects.
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BACKGROUND Alterations in the cadherin-catenin adhesion complexes are involved in tumor initiation, progression and metastasis. However, the functional implication of distinct cadherin types in breast cancer biology is still poorly understood. METHODS To compare the functional role of E-cadherin and P-cadherin in invasive breast cancer, we stably transfected these molecules into the MDA-MB-231 cell line, and investigated their effects on motility, invasion and gene expression regulation. RESULTS Expression of either E- and P-cadherin significantly increased cell aggregation and induced a switch from fibroblastic to epithelial morphology. Although expression of these cadherins did not completely reverse the mesenchymal phenotype of MDA-MB-231 cells, both E- and P-cadherin decreased fibroblast-like migration and invasion through extracellular matrix in a similar way. Moreover, microarray gene expression analysis of MDA-MB-231 cells after expression of E- and P-cadherins revealed that these molecules can activate signaling pathways leading to significant changes in gene expression. Although the expression patterns induced by E- and P-cadherin showed more similarities than differences, 40 genes were differentially modified by the expression of either cadherin type. CONCLUSION E- and P-cadherin have similar functional consequences on the phenotype and invasive behavior of MDA-MB-231 cells. Moreover, we demonstrate for the first time that these cadherins can induce both common and specific gene expression programs on invasive breast cancer cells. Importantly, these identified genes are potential targets for future studies on the functional consequences of altered cadherin expression in human breast cancer.
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BACKGROUND Previous studies have demonstrated the efficacy of treatment for latent tuberculosis infection (TLTBI) in persons infected with the human immunodeficiency virus, but few studies have investigated the operational aspects of implementing TLTBI in the co-infected population.The study objectives were to describe eligibility for TLTBI as well as treatment prescription, initiation and completion in an HIV-infected Spanish cohort and to investigate factors associated with treatment completion. METHODS Subjects were prospectively identified between 2000 and 2003 at ten HIV hospital-based clinics in Spain. Data were obtained from clinical records. Associations were measured using the odds ratio (OR) and its 95% confidence interval (95% CI). RESULTS A total of 1242 subjects were recruited and 846 (68.1%) were evaluated for TLTBI. Of these, 181 (21.4%) were eligible for TLTBI either because they were tuberculin skin test (TST) positive (121) or because their TST was negative/unknown but they were known contacts of a TB case or had impaired immunity (60). Of the patients eligible for TLTBI, 122 (67.4%) initiated TLTBI: 99 (81.1%) were treated with isoniazid for 6, 9 or 12 months; and 23 (18.9%) with short-course regimens including rifampin plus isoniazid and/or pyrazinamide. In total, 70 patients (57.4%) completed treatment, 39 (32.0%) defaulted, 7 (5.7%) interrupted treatment due to adverse effects, 2 developed TB, 2 died, and 2 moved away. Treatment completion was associated with having acquired HIV infection through heterosexual sex as compared to intravenous drug use (OR:4.6; 95% CI:1.4-14.7) and with having taken rifampin and pyrazinamide for 2 months as compared to isoniazid for 9 months (OR:8.3; 95% CI:2.7-24.9). CONCLUSIONS A minority of HIV-infected patients eligible for TLTBI actually starts and completes a course of treatment. Obstacles to successful implementation of this intervention need to be addressed.
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Nutritional support in acute renal failure must take into account the patient's catabolism and the treatment of the renal failure. Hypermetabolic failure is common in these patients, requiring continuous renal replacement therapy or daily hemodialysis. In patients with normal catabolism (urea nitrogen below 10 g/day) and preserved diuresis, conservative treatment can be attempted. In these patients, relatively hypoproteic nutritional support is essential, using proteins with high biological value and limiting fluid and electrolyte intake according to the patient's individual requirements. Micronutrient intake should be adjusted, the only buffering agent used being bicarbonate. Limitations on fluid, electrolyte and nitrogen intake no longer apply when extrarenal clearance techniques are used but intake of these substances should be modified according to the type of clearance. Depending on their hemofiltration flow, continuous renal replacement systems require high daily nitrogen intake, which can sometimes reach 2.5 g protein/kg. The amount of volume replacement can induce energy overload and therefore the use of glucose-free replacement fluids and glucose-free dialysis or a glucose concentration of 1 g/L, with bicarbonate as a buffer, is recommended. Monitoring of electrolyte levels (especially those of phosphorus, potassium and magnesium) and of micronutrients is essential and administration of these substances should be individually-tailored.