RESUMO
Colorectal cancer (CRC) is the third most common cancer and the second most deathly worldwide. It is a very heterogeneous disease that can develop via distinct pathways where metastasis is the primary cause of death. Therefore, it is crucial to understand the molecular mechanisms underlying metastasis. RNA-sequencing is an essential tool used for studying the transcriptional landscape. However, the high-dimensionality of gene expression data makes selecting novel metastatic biomarkers problematic. To distinguish early-stage CRC patients at risk of developing metastasis from those that are not, three types of binary classification approaches were used: (1) classification methods (decision trees, linear and radial kernel support vector machines, logistic regression, and random forest) using differentially expressed genes (DEGs) as input features; (2) regularized logistic regression based on the Elastic Net penalty and the proposed iTwiner-a network-based regularizer accounting for gene correlation information; and (3) classification methods based on the genes pre-selected using regularized logistic regression. Classifiers using the DEGs as features showed similar results, with random forest showing the highest accuracy. Using regularized logistic regression on the full dataset yielded no improvement in the methods' accuracy. Further classification using the pre-selected genes found by different penalty factors, instead of the DEGs, significantly improved the accuracy of the binary classifiers. Moreover, the use of network-based correlation information (iTwiner) for gene selection produced the best classification results and the identification of more stable and robust gene sets. Some are known to be tumor suppressor genes (OPCML-IT2), to be related to resistance to cancer therapies (RAC1P3), or to be involved in several cancer processes such as genome stability (XRCC6P2), tumor growth and metastasis (MIR602) and regulation of gene transcription (NME2P2). We show that the classification of CRC patients based on pre-selected features by regularized logistic regression is a valuable alternative to using DEGs, significantly increasing the models' predictive performance. Moreover, the use of correlation-based penalization for biomarker selection stands as a promising strategy for predicting patients' groups based on RNA-seq data.
Assuntos
Neoplasias Colorretais , Humanos , Biomarcadores , Modelos Logísticos , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Moléculas de Adesão Celular , Proteínas Ligadas por GPIRESUMO
Introduction: The COVID-19 outbreak and the community mitigation strategies implemented to reduce new SARS-CoV-2 infections can be regarded as powerful stressors with negative consequences on people's mental health. Although it has been shown that negative emotional symptoms subside during lockdown, it is likely the existence of inter-individual differences in stress, anxiety and depression trajectories throughout lockdown. Objectives: We aimed to cluster participants' according to their trajectories of stress, anxiety and depression scores throughout lockdown, and identify the sociodemographic, clinical, and lifestyle factors that may distinguish the subjects included in the different clusters. Methods: From March 23, 2020, to May 31, 2020, participants completed weekly online questionnaires on sociodemographic information (age, sex, education level, and employment status), psychological functioning (DASS-21, NEO-FFI-20), and clinical data (psychiatric disorders, psychiatric medication, physical disorders). Data regarding smoking status, alcohol consumption, physical activity, and time spent daily looking for COVID-19-related information were also collected. Stress, anxiety and depression trajectories were determined using latent class mixed models. Results: A total of 2040 participants answered the survey at baseline and 603 participants answered all surveys. Three groups ("Resilient," "Recovered," and "Maladaptive") with distinct mental health trajectories were identified. Younger participants, women, participants with lower education level, not working, studying, diagnosed with a mental disorder, taking psychiatric medication, smokers, those who spent more time consuming COVID-19-related information and those with higher neuroticism tended to cluster in the "Maladaptive" group, placing them at higher risk of persistent negative emotional symptoms during compulsory confinement. Conclusion: Accordingly, a tailored approach to emotional suffering for vulnerable subjects during the COVID-19 and future pandemics must be devised.
Assuntos
COVID-19 , Humanos , Feminino , COVID-19/epidemiologia , COVID-19/psicologia , Pandemias , Depressão/epidemiologia , Depressão/psicologia , Portugal/epidemiologia , SARS-CoV-2 , Estresse Psicológico/epidemiologia , Estresse Psicológico/psicologia , Controle de Doenças Transmissíveis , Ansiedade/epidemiologia , Ansiedade/psicologiaRESUMO
Severe forms of malaria infection, such as cerebral malaria (CM) and acute lung injury (ALI), are mainly caused by the apicomplexan parasite Plasmodium falciparum. Primary therapy with quinine or artemisinin derivatives is generally effective in controlling P. falciparum parasitemia, but mortality from CM and other forms of severe malaria remains unacceptably high. Herein, we report the design and synthesis of a novel carbon monoxide-releasing molecule (CO-RM; ALF492) that fully protects mice against experimental CM (ECM) and ALI. ALF492 enables controlled CO delivery in vivo without affecting oxygen transport by hemoglobin, the major limitation in CO inhalation therapy. The protective effect is CO dependent and induces the expression of heme oxygenase-1, which contributes to the observed protection. Importantly, when used in combination with the antimalarial drug artesunate, ALF492 is an effective adjunctive and adjuvant treatment for ECM, conferring protection after the onset of severe disease. This study paves the way for the potential use of CO-RMs, such as ALF492, as adjunctive/adjuvant treatment in severe forms of malaria infection.
Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Antimaláricos/síntese química , Monóxido de Carbono/metabolismo , Malária Cerebral/tratamento farmacológico , Compostos Organometálicos/síntese química , Plasmodium berghei/efeitos dos fármacos , Tiogalactosídeos/síntese química , Lesão Pulmonar Aguda/metabolismo , Lesão Pulmonar Aguda/microbiologia , Animais , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Carboxihemoglobina/metabolismo , Regulação da Expressão Gênica , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Humanos , Malária Cerebral/metabolismo , Malária Cerebral/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Compostos Organometálicos/farmacologia , Compostos Organometálicos/uso terapêutico , Plasmodium berghei/fisiologia , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/fisiologia , Índice de Gravidade de Doença , Tiogalactosídeos/farmacologia , Tiogalactosídeos/uso terapêuticoRESUMO
UNLABELLED: Easy access to echocardiography and its extensive and repeated use (as is the case in Portugal) now facilitates the early diagnosis of cardiac myxoma (CM). OBJECTIVE: To re-evaluate the clinical and pathological profile of CM under current diagnostic conditions. METHODS: We performed a retrospective study of 40 patients consecutively referred for surgery (between January 2003 and January 2010) with a histologically-confirmed diagnosis of CM - 26 female (F) and 14 male (M), with a mean age of 64±12 years (range 12-81; 53% over 65, 43% over 70); 39 patients were operated (one was not operable due to major neurological deficit). Clinical characteristics, surgical protocols, follow-up records of survivors (range 1-76 months, with serial echocardiograms), and histological data were reviewed. RESULTS: The apparent incidence was 2.6 cases/million/year; the overall F/M ratio was 1.9:1 (1.3:1 in those aged over 65, similar to the general population). The CM was located in the left atrium (LA) in 92.5%, with insertion in the fossa ovalis of the interatrial septum (IAS) in 53% (only 57% of LA myxomas), and outside the IAS in 30%. The mean size was 4.6 x 3.7cm. Asymptomatic tumors occurred in 48% of the total population (sessile and/or atypically inserted in 74%; 63% of large size, over 3 x 3cm), 61% were in patients referred in the last 25 months of the study; 23% of patients showed constitutional symptoms (all with very large CMs - mean 6.7 x 5.1cm), 35% had hemodynamic/obstructive symptoms, and 15% presented with embolic events. There was evidence of CM-related mitral valve (MV) disease in 20% of patients, resulting in moderate to severe mitral regurgitation requiring associated MV surgery in 13%. Significant comorbidities were present in 69%. Surgical procedures included simple excision in 74%; septoplasty/atrioplasty associated with extensive resection of the insertion site in 26%; and combined surgery (CM excision plus other procedures) in 28%. There were significant postoperative complications in 38%. In-hospital mortality was 10%; postoperative mortality was 7.7%. Mean follow-up was 30 months (100% of survivors, 44% for >2 years); late mortality was 5.6% and no CM recurrences were observed. CONCLUSIONS: (1) CM has a higher incidence than described in the literature and mainly affects patients aged over 65; the reported predominance of female patients disappears after the age of 65. (2) Most CM cases are now asymptomatic at presentation as a result of earlier diagnosis. (3) CM is the cause of MV disease requiring surgical correction in more than 10% of cases, and is associated with significant postoperative mortality, mainly due to the presence of comorbidities.
Assuntos
Neoplasias Cardíacas/diagnóstico , Mixoma/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Neoplasias Cardíacas/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Mixoma/patologia , Estudos Retrospectivos , Adulto JovemRESUMO
During the first COVID-19 related confinement in Portugal, there was a decrease in the levels of psychological symptoms measured by the Depression, Anxiety and Stress Scale 21 (March to April 2020). Upon experiencing a new period of restraints in 2021, the psychological impact of this sample was assessed again (N = 322, two more time points). It was expected that the psychological symptoms evidenced in February 2021 would be at similar levels to those found in April 2020, leading to a transfer of adaptation. Contrary to our hypothesis, in the second confinement in Portugal there were higher levels of depression and stress symptoms than at the beginning of the pandemic. On the other hand, the maximum level of anxiety was observed in March 2020. It seems that our perception of the threats in 2021 was not the same as at the onset of COVID-19, or that knowledge was not disseminated to the general population to increase their mental health literacy and help them cope with the imposed challenges.
Assuntos
COVID-19 , Depressão , Ansiedade/epidemiologia , Ansiedade/psicologia , COVID-19/epidemiologia , Depressão/epidemiologia , Depressão/psicologia , Humanos , Portugal/epidemiologia , SARS-CoV-2 , Estresse Psicológico/epidemiologia , Estresse Psicológico/psicologiaRESUMO
PURPOSE: Cetuximab is an EGFR-targeted therapy approved for the treatment of RAS wild-type (WT) metastatic colorectal cancer (mCRC). However, about 60% of these patients show innate resistance to cetuximab. To increase cetuximab efficacy, it is crucial to successfully identify responder patients, as well as to develop new therapeutic approaches to overcome cetuximab resistance. EXPERIMENTAL DESIGN: We evaluated the value of EGFR effector phospholipase C gamma 1 (PLCγ1) in predicting cetuximab responses, by analyzing progression-free survival (PFS) of a multicentric retrospective cohort of 94 treated patients with mCRC (log-rank test and Cox regression model). Furthermore, we used in vitro and zebrafish xenotransplant models to identify and target the mechanism behind PLCγ1-mediated resistance to cetuximab. RESULTS: In this study, levels of PLCγ1 were found increased in RAS WT tumors and were able to predict cetuximab responses in clinical samples and in vitro and in vivo models. Mechanistically, PLCγ1 expression was found to bypass cetuximab-dependent EGFR inhibition by activating ERK and AKT pathways. This novel resistance mechanism involves a noncatalytic role of PLCγ1 SH2 tandem domains in the propagation of downstream signaling via SH2-containing protein tyrosine phosphatase 2 (SHP2). Accordingly, SHP2 inhibition sensitizes PLCγ1-resistant cells to cetuximab. CONCLUSIONS: Our discoveries reveal the potential of PLCγ1 as a predictive biomarker for cetuximab responses and suggest an alternative therapeutic approach to circumvent PLCγ1-mediated resistance to cetuximab in patients with RAS WT mCRC. In this way, this work contributes to the development of novel strategies in the medical management and treatment of patients with mCRC.
Assuntos
Neoplasias do Colo , Neoplasias Colorretais , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Neoplasias Retais , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Cetuximab/farmacologia , Cetuximab/uso terapêutico , Neoplasias do Colo/tratamento farmacológico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Receptores ErbB/genética , Humanos , Mutação , Fosfolipase C gama/genética , Proteínas Proto-Oncogênicas p21(ras) , Neoplasias Retais/tratamento farmacológico , Estudos Retrospectivos , Peixe-ZebraRESUMO
Colorectal cancer (CRC) is a highly diverse disease, where different genomic instability pathways shape genetic clonal diversity and tumor microenvironment. Although intra-tumor heterogeneity has been characterized in primary tumors, its origin and consequences in CRC outcome is not fully understood. Therefore, we assessed intra- and inter-tumor heterogeneity of a prospective cohort of 136 CRC samples. We demonstrate that CRC diversity is forged by asynchronous forms of molecular alterations, where mutational and chromosomal instability collectively boost CRC genetic and microenvironment intra-tumor heterogeneity. We were able to depict predictor signatures of cancer-related genes that can foresee heterogeneity levels across the different tumor consensus molecular subtypes (CMS) and primary tumor location. Finally, we show that high genetic and microenvironment heterogeneity are associated with lower metastatic potential, whereas late-emerging copy number variations favor metastasis development and polyclonal seeding. This study provides an exhaustive portrait of the interplay between genetic and microenvironment intra-tumor heterogeneity across CMS subtypes, depicting molecular events with predictive value of CRC progression and metastasis development.
Assuntos
Neoplasias Colorretais , Variações do Número de Cópias de DNA , Neoplasias Colorretais/genética , Humanos , Oncogenes , Estudos Prospectivos , Microambiente Tumoral/genéticaRESUMO
Colorectal cancer (CRC) is one of the most lethal malignancies. The extreme heterogeneity in survival rate is driving the need for new prognostic biomarkers. Human endogenous retroviruses (hERVs) have been suggested to influence tumor progression, oncogenesis and elicit an immune response. We examined multiple next-generation sequencing (NGS)-derived biomarkers in 114 CRC patients with paired whole-exome and whole-transcriptome sequencing (WES and WTS, respectively). First, we demonstrate that the median expression of hERVs can serve as a potential biomarker for prognosis, relapse, and resistance to chemotherapy in stage II and III CRC. We show that hERV expression and CD8+ tumor-infiltrating T-lymphocytes (TILs) synergistically stratify overall and relapse-free survival (OS and RFS): the median OS of the CD8-/hERV+ subgroup was 29.8 months compared with 37.5 months for other subgroups (HR = 4.4, log-rank P < 0.001). Combing NGS-based biomarkers (hERV/CD8 status) with clinicopathological factors provided a better prediction of patient survival compared to clinicopathological factors alone. Moreover, we explored the association between genomic and transcriptomic features of tumors with high hERV expression and establish this subtype as distinct from previously described consensus molecular subtypes of CRC. Overall, our results underscore a previously unknown role for hERVs in leading to a more aggressive subtype of CRC.
RESUMO
Left ventricular non-compaction (LVNC) is a rare disorder of endomyocardial morphogenesis that results in multiple trabeculations and deep intertrabecular recesses filled with direct blood flow from the left ventricular cavity. LVNC is attracting increasing interest as a model for the study of cardiomyopathies, since it is a genetically heterogeneous disorder which varies greatly in clinical presentation and age of onset. The authors present the case of a young black male with progressive congestive heart failure of 2-3 years' evolution. The investigation, which included transthoracic echocardiography (contrast and 3D), transesophageal echocardiography and cardiac magnetic resonance imaging, showed LVNC and severe aortic regurgitation, with severe left ventricular systolic dysfunction. The family history was suggestive of genetically transmitted disease and genetic study of the TAZ gene at locus Xq28 identified the mutation p.Phe128Ser (c.383T>C), the first description of this mutation in a patient with LVNC. The patient underwent aortic valve replacement, with excellent clinical evolution, regression of left ventricular dimensions and global systolic functio Aortic regurgitation (not related to LVNC) was the determining factor in the clinical expression. However, the excellent reverse remodeling that occurred after surgery highlights the heterogeneity of myocardial behavior in LVNC patients.
Assuntos
Cardiomiopatias/genética , Ventrículos do Coração , Mutação , Remodelação Ventricular/genética , Adolescente , Predisposição Genética para Doença , Humanos , Masculino , LinhagemRESUMO
The authors report the clinical case of a 56 years old man who developed a deep venous thrombosis of the left lower extremity, managed conventionally with subcutaneous heparin. Physical examination revealed a large tumor of the middle third, antero lateral view of the left thigh. CT and NMR studies, disclosed an extensive multilobulated tumor along the femoral vessels, with medial deviation of the superficial femoral artery and a surgical biopsy revealed the diagnosis of leiomyosarcoma of the femoral vein, grade 3 of malignancy. The patient underwent a complete resection of the tumor, followed by chemotherapy. Two months after the operation a staging CT scan disclosed multiple micronodular metastasis in both lungs and six months later he was found asymptomatic and in good condition. A review of the literature concerning primary malignant tumors of the veins of the extremities is made, with emphasis on main features of its biology, clinical presentation, methods of diagnosis, treatment and results.
Assuntos
Veia Femoral , Leiomiossarcoma , Neoplasias Vasculares , Humanos , Leiomiossarcoma/diagnóstico , Leiomiossarcoma/cirurgia , Masculino , Pessoa de Meia-Idade , Neoplasias Vasculares/diagnóstico , Neoplasias Vasculares/cirurgiaRESUMO
The celiac axis compression syndrome caused by the median arcuate ligament of the diaphragm is an exceedingly rare clinical entity, coursing with postprandial abdominal pain, nausea, vomiting and weight loss. Despite the original description made some decades ago, its existence is still challenged by some authors, due to a weak clinicopathological correlation and inconstant results obtained with its surgical management. The authors report the case of a 35 years old female with the clinical presentation above described, who underwent an exhaustive investigation in gastroenterology, leading to the diagnosis, made by CT-scans and conventional angiography, of celiac axis compression syndrome by the median arcuate ligament of the diaphragm. A definitive surgical repair was performed, consisting in the ligament division, followed by resection and replacement of the celiac axis, by a 6 mms PTFE grafts. The post-operative course was uneventful and reviewed one month later, the patient was found in excellent condition and completely free of symptoms. Pathological studies of the celiac axis disclosed significant proliferative and degenerative lesions of the arterial wall, consequence of the compression mechanism, a fact that has not been reported in previous similar publications. The main feature of this unique clinical entity and its surgical management are discussed, based on a review of the most recent publications of the literature.
Assuntos
Artéria Celíaca , Ligamentos , Doenças Musculoesqueléticas/complicações , Doenças Musculoesqueléticas/cirurgia , Doenças Vasculares/etiologia , Doenças Vasculares/cirurgia , Adulto , Diafragma , Feminino , Humanos , Doenças Musculoesqueléticas/diagnóstico , Síndrome , Doenças Vasculares/diagnósticoRESUMO
Fibromuscular dysplasia (FMD) is a noninflammatory, nonatherosclerotic sistemic disease of unknown etiology, primarily affecting muscular arteries of intermediate size. It has been most commonly observed in the renal, carotid, and intracerebral arteries, although it has been reported in other arterial beds. However, being an uncommon disease in general, the manifestation of FMD in the upper extremities is exceedingly rare. The authors report the case of a 69 years old female admitted with ischemia of the right hand, secondary to fibromuscular dysplasia of the midbrachial artery. The patient presented to vascular surgery clinic with a 4 month history of numbness, pain, and coolness of her right hand, with a small necrotic lesion on her right index finger. Peripheral pulses were barely palpable, and doppler-derived brachial and radial systolic pressures suggested midbrachial artery stenosis. Arteriography showed a normal arch and normal innominate, subclavian, and axillary arteries. The midbrachial artery was markedly abnormal and had alternating areas of stenosis and aneurysm formation - "string-of-beads" appearance. The patient underwent surgical excision of the abnormal right brachial artery, and reconstruction was accomplished with a reversed saphenous vein graft. Distal pulses were restored postoperatively. Pathologic examination confirmed the diagnosis of fibromuscular dysplasia. A review of the literature on the topic was made.
Assuntos
Braço/irrigação sanguínea , Artéria Braquial , Displasia Fibromuscular/complicações , Isquemia/etiologia , Idoso , Feminino , HumanosRESUMO
The clinical case of a 39 years old female is reported, with the diagnosis of tumor of the right kidney extending into the infra-hepatic vena cava, assuming the shape of a floating thrombus. The patient underwent right radical nephrectomy, followed by resection of the intra caval tumor. Both the procedure and post operative course were uneventfull. Histopathological evaluation of the specimens, associated to specific imunohistochemistry studies, confirmed the diagnosis of angiomyolipoma of the kidney. A review of the literature concluded that this is the 27th case published of a kidney angiomyolipoma extending into the inferior vena cava, thus justifying its presentation and divulgation.
Assuntos
Angiomiolipoma/patologia , Angiomiolipoma/cirurgia , Neoplasias Renais/patologia , Células Neoplásicas Circulantes , Veia Cava Inferior , Adulto , Feminino , Humanos , Indução de Remissão , Procedimentos Cirúrgicos Vasculares/métodosRESUMO
INTRODUCTION: DNA damaging agents and ionizing radiation used in the therapy of human cancers can induce senescence of cancer cells. Senescent cells exhibit a secretory phenotype (senescence-associated secretome [SAS]) that can affect cancer cell behavior and, eventually, clinical prognosis. We assessed the effects of the SAS on the induction of epithelial-to-mesenchymal transition (EMT) in vitro and in clinical samples from patients with rectal cancer who had undergone neoadjuvant chemoradiotherapy (CRT). MATERIALS AND METHODS: Colorectal cancer cells (HCT 116) were induced into senescence by exposure to either 5-fluorouracil (5-FU) or doxorubicin. The senescent state was confirmed by staining for senescence-associated ß-galactosidase (SA-ß-Gal). The paracrine effects of SASs were assessed on proliferating HCT 116 cells. The quantified parameters were cell proliferation, invasive capacity, and induction of EMT. Senescence and EMT in clinical samples were assessed by the expression levels (reverse transcriptase-quantitative polymerase chain reaction) of genes related to senescence and EMT after laser-assisted microdissection of cancer cell clusters that stained either positive or negative for SA-ß-Gal. RESULTS: We have shown that cultured colon cancer cells induced into senescence by exposure to 5-FU exhibit a SAS capable of paracrine induction of EMT in colon and rectal cancer cell lines and increased cell invasion in vitro. Using laser-assisted microdissection, we found that in rectal cancer samples from patients treated with neoadjuvant CRT, tumor cell niches enriched for senescent cells bookmark regions of increased mRNA expression levels of EMT-related proteins (Slug, Snail, vimentin) compared with the nearby senescent-null tumor cell niches. CONCLUSION: We have provided, first-hand, strongly suggestive evidence that senescent cancer cells emerging in the context of neoadjuvant CRT for rectal cancer influenced the tumor microenvironment by promoting EMT by way of short-range interactions.
Assuntos
Antineoplásicos/farmacologia , Senescência Celular/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Neoplasias Retais/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Doxorrubicina/farmacologia , Feminino , Imunofluorescência , Fluoruracila/farmacologia , Células HCT116 , Humanos , Microdissecção e Captura a Laser , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Microambiente TumoralRESUMO
Neutral tryptophan (*Trp) and tyrosine (TyrO(*)) radicals are repaired by certain flavonoids in buffer, in micelles and in human serum albumin (HSA) with corresponding formation of semioxidized flavonoid radicals. In deaerated buffer, *Trp but not TyrO(*) radicals react with catechin. In micelles, quercetin and rutin repair both *Trp and TyrO(*) radicals. In addition to amino acid reactivity, microenvironmental factors and nature of the flavonoids govern this repair. Electron transfer efficiencies from quercetin to negatively charged *Trp radicals are 100% in the micellar pseudophases of positively charged cetyltrimethylammonium bromide, (CTAB), and neutral Triton X100 (TX100), but 55% in negatively charged sodium dodecyl sulfate (SDS). In oxygen-saturated CTAB micelles, quercetin also reacts with the superoxide radical anion. When bound to domain IIA of HSA, quercetin repairs, by intra- or intermolecular encounter, less than 20% of oxidative damage to HSA. Quercetin can also repair freely circulating oxidized molecules with repair efficiencies falling to 7% for oxidized *Trp, Tyr and alpha-MSH and to less than 2% for urate radical. This limited effectiveness is attributed both to the inaccessibility of bound quercetin and rutin toward radicals of circulating molecules and to the diffusion-controlled recombination of these radicals.
Assuntos
Flavonoides/química , Albumina Sérica/química , Triptofano/química , Tirosina/química , Catequina/química , Transporte de Elétrons , Radicais Livres/química , Concentração de Íons de Hidrogênio , Micelas , Modelos Biológicos , Oxirredução , Radiólise de Impulso , Quercetina/química , Rutina/química , Triptofano/análogos & derivados , Tirosina/análogos & derivados , Ácido Úrico/química , alfa-MSH/químicaRESUMO
Neutral tryptophan (*Trp) and tyrosine (TyrO(*)) radicals are repaired by certain flavonoids in buffer, in micelles and in human serum albumin (HSA) with corresponding formation of semioxidized flavonoid radicals. In deaerated buffer, *Trp but not TyrO(*) radicals react with catechin. In micelles, quercetin and rutin repair both *Trp and TyrO(*) radicals. In addition to amino acid reactivity, microenvironmental factors and nature of the flavonoids govern this repair. Electron transfer efficiencies from quercetin to negatively charged *Trp radicals are 100% in the micellar pseudophases of positively charged cetyltrimethylammonium bromide, (CTAB), and neutral Triton X100 (TX100), but 55% in negatively charged sodium dodecyl sulfate (SDS). In oxygen-saturated CTAB micelles, quercetin also reacts with the superoxide radical anion. When bound to domain IIA of HSA, quercetin repairs, by intra- or intermolecular encounter, less than 20% of oxidative damage to HSA. Quercetin can also repair freely circulating oxidized molecules with repair efficiencies falling to 7% for oxidized Trp, Tyr and alpha-MSH and to less than 2% for urate radical. This limited effectiveness is attributed both to the inaccessibility of bound quercetin and rutin toward radicals of circulating molecules and to the diffusion-controlled recombination of these radicals.
Assuntos
Flavonoides/química , Albumina Sérica/química , Triptofano/química , Tirosina/química , Catequina/química , Transporte de Elétrons , Radicais Livres/química , Concentração de Íons de Hidrogênio , Micelas , Modelos Biológicos , Oxirredução , Radiólise de Impulso , Quercetina/química , Rutina/química , Triptofano/análogos & derivados , Tirosina/análogos & derivados , Ácido Úrico/química , alfa-MSH/químicaRESUMO
BACKGROUND: Data concerning the effectiveness of Helicobacter pylori eradication regimens based in antibiotic susceptibility testing are scanty in children. AIMS: To identify the prevalence of antibiotic resistance in H. pylori strains isolated from Portuguese children in 1999-2003; to evaluate eradication rate after antibiotic susceptibility testing-based treatment; and to identify factors associated with resistance and eradication outcome. METHODS: Included were 109 children with a gastric biopsy culture positive for H. pylori. First treatment (amoxicillin, omeprazole and clarithromycin or metronidazole) was guided by susceptibility testing (E test), and eradication was assessed by [C]urea breath test. RESULTS: Strains were susceptible to amoxicillin and tetracycline; 39.4% were resistant to clarithromycin, 16.5% to metronidazole and 4.5% to ciprofloxacin. No significant association was found between resistance and sex, age, clinical status, gastritis scores, H. pylori density scores and genotype. Clarithromycin resistance was significantly associated with European origin [odds ratio (OR), 3.9], previous H. pylori empiric therapy (OR 2.8) and amoxicillin minimal inhibitory concentration, > or =0.016 (OR 6.0). Eradication rate after susceptibility-based treatment was 74.7% (59 of 79; 95% confidence interval, 65.9-82.9), and a significant association was found between eradication failure and presence of resistance to 1 or more antibiotics (P < 0.05). CONCLUSIONS: The prevalence of H. pylori antibiotic resistance was high in the studied population. The modest therapeutic success of clarithromycin and metronidazole susceptibility-based regimens suggests that in addition to resistance, other factors may be involved. The need of susceptibility-based treatment studies in children and of antimicrobial resistance surveillance in high prevalence areas for H. pylori are emphasized.
Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/efeitos dos fármacos , Adolescente , Distribuição por Idade , Antibacterianos/uso terapêutico , Testes Respiratórios , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Gastroscopia/métodos , Infecções por Helicobacter/diagnóstico , Helicobacter pylori/isolamento & purificação , Humanos , Masculino , Testes de Sensibilidade Microbiana , Análise Multivariada , Razão de Chances , Portugal/epidemiologia , Prevalência , Probabilidade , Prognóstico , Medição de Risco , Índice de Gravidade de Doença , Distribuição por SexoRESUMO
BACKGROUND/AIMS: Oxidative stress is involved in chronic hepatitis C, and efforts have been made to influence the disease process with antioxidants. The present study evaluates the protective effects of a phenol-rich processed grain food with superoxide-scavenging properties (trade name antioxidant biofactor AOB). METHODOLOGY: Thirty patients participated in this placebo-controlled double-blind pilot study. AOB was taken orally by fifteen patients for 3 mo at the recommended daily dose of 3x2 sachets, containing 3 g of powder each. Another fifteen patients received a herbal extract with practically no superoxide scavenging properties as a placebo. Oxidative stress biomarkers, aminotransferase levels and viral load were evaluated immediately before and after treatment. RESULTS: AOB treatment considerably improved the antioxidant defenses. Also ALT and AST decreased in 11 of the 15 patients (-11% to -65%, mean -22%, p<0.05). The effects of placebo were not significant. Viral load remained unchanged. Control biopsies were not done after the short interval of 3 mo. There were no adverse effects. After the 3-mo treatment with AOB or placebo, 16 of the 30 patients received conventional antiviral treatment (pegylated interferon alpha and ribavirin). A sustained response was observed in 5 of 9 AOB pretreated patients six mo after discontinuation of the 12-mo antiviral therapy. The 7 patients pretreated with placebo were all non-responders. CONCLUSIONS: These preliminary results are encouraging to conduct more extensive clinical studies combining antioxidant with antiviral treatment in hepatitis C.
Assuntos
Antioxidantes/uso terapêutico , Citoproteção , Flavonoides/uso terapêutico , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fenóis/uso terapêutico , Extratos Vegetais/uso terapêutico , Adulto , Idoso , Antivirais/administração & dosagem , Antivirais/uso terapêutico , Biomarcadores/metabolismo , Método Duplo-Cego , Esquema de Medicação , Quimioterapia Combinada , Feminino , Humanos , Interferon alfa-2 , Interferon-alfa/administração & dosagem , Interferon-alfa/uso terapêutico , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Polietilenoglicóis/administração & dosagem , Polietilenoglicóis/uso terapêutico , Proteínas Recombinantes , Ribavirina/administração & dosagem , Ribavirina/uso terapêutico , Transaminases/sangue , Resultado do TratamentoRESUMO
The 1:1 complex of copper (II) and human serum albumin (HSA) slowly reacts with radiolytically generated *O2- radical-anion at a rate constant of 6.1 x 10(6) M(-1) s(-1). Absorbance and fluorescence spectroscopies demonstrate that addition of an equimolar portion of quercetin (QH2) to the solution of the copper (II)-HSA complex induces a relocalization of the copper resulting in a ternary copper (II)-QH2-HSA complex. This form of quercetin slowly oxidizes in air-saturated solutions. A 10-fold excess urate, a plasma antioxidant, cannot displace copper (II) bound to HSA. In N2O-saturated solutions the ternary complex form of QH2 can repair the urate radical with a rate constant of 2.7 x 10(6) M(-1) s(-1) by an electron transfer reaction similar to that observed in the absence of copper (II). In O2-saturated solutions and in the absence of copper, HSA-bound QH2 fails to repair the urate radical because of the fast competitive reaction of *O2- with urate radicals. However, addition of equimolar copper (II) restores the electron transfer from QH2 to the urate radical. These contrasting results are tentatively explained either by an enhanced reactivity of copper (II) with *O2- in the ternary complex or by direct production of quercetin radicals via a copper-catalyzed reduction of the *O2- radicals by QH2.
Assuntos
Cobre/química , Oxigênio/química , Quercetina/química , Albumina Sérica/química , Ácido Úrico/química , Radicais Livres/química , Humanos , Ligantes , Estrutura Molecular , OxirreduçãoRESUMO
AIMS: To evaluate the oxidative stress parameters before, during and after interferon treatment. PATIENTS/METHODS: Twenty patients were treated with interferon a2b 5 MU, three times a week, subcutaneously, for 12 months. Liver biopsy was performed six months before treatment and at the six month follow-up. Chromosomal breakage studies were evaluated by the adjusted clastogenic score (ACS, normal value [nv] 1.1 +/- 2.4%). Plasma malondialdehyde (MDA) was measured according to the Yagi method (nv 6.6 +/- 1.4 nmol/mL) and total thiols using the Ellman's reagent (DTNB) (nv 9.8 +/- 1.3 micromol/g protein). A serum marker of fibrogenesis, the amino-terminal propeptide of Procollagen type III (PIIIP), was quantified by radioimmunoassay (nv 0.37 +/- 0.18 U/L). RESULTS: Compared with reference samples, the plasma of patients before treatment showed an increase of ACS (9.2 +/- 3.2%, P<0.001); higher MDA values (12.6 +/- 2.7 nmol/mL, P<0.001) and total plasma sulfhydryl groups (t-SH) were decreased (6.3 +/- 1.1 micromol/g protein, P<0.001). During treatment and at the follow-up, a decrease in ACS was noticed in all patients (P<0.001), but without normalization; a decrease in MDA was seen, with progressive normalization until the end of the follow up only in sustained responders (P<0.003), while an increase of t-SH was seen, with progressive normalization until the end of follow up in all patients (P<0.005). A positive correlation of ACS with grading of inflammation was found (r=0.52, P<0.03) but not with fibrosis staging. In contrast, plasma MDA correlates with fibrosis staging (r=0.51, P<0.03) and with PIIIP (r=0.57, P<0.03) but without grading of inflammation. CONCLUSIONS: The present study confirmed the presence of oxidative stress in chronic hepatitis C patients. Interferon promotes a long term inhibition of oxidative stress with concomitant improvement of activity and fibrosis. In the management of chronic hepatitis C, adjuvant therapy with antioxidants could be useful.