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1.
Environ Res ; 170: 406-415, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30623888

RESUMO

Bisphenol A (BPA) is a high-production-volume chemical with endocrine disrupting properties commonly used as color developer in thermal paper. Concerns about the potential hazards of human BPA exposure have led to the increasing utilization of alternatives such as bisphenol S (BPS) and bisphenol F (BPF). This study was designed to assess: (i) BPA, BPS, and BPF concentrations in 112 thermal paper receipts from Brazil, France, and Spain by liquid chromatography coupled to mass spectrometry (LC-MS); and (ii) hormone-like activities of these receipts using two receptor-specific bioassays, the E-Screen for (anti-)estrogenicity and PALM luciferase assay for (anti-)androgenicity. BPA was present in 95.3% of receipts from Spain, 90.9% of those from Brazil, and 51.1% of those from France at concentrations up to 20.27 mg/g of paper. Only two samples from Brazil, two from Spain, and ten from France had a BPS concentration ranging from 6.46 to 13.29 mg/g; no BPA or BPS was detected in 27.7% of French samples. No BPF was detected in any receipt. Estrogenic activity was observed in all samples from Brazil and Spain and in 74.5% of those from France. Anti-androgenic activity was observed in > 90% of samples from Brazil and Spain and in 53.2% of those from France. Only 25.5% of French samples were negative for both estrogenic and anti-androgenic activity. Estrogenic and anti-androgenic activities per gram of paper were up to 1.411 µM estradiol (E2) equivalent units (E2eq) and up to 359.5 mM procymidone equivalent units (Proceq), respectively. BPA but not BPS concentrations were positively correlated with both estrogenic and anti-androgenic activities. BPA still dominates the thermal paper market in Brazil and Spain, and BPS appears to be one of the main alternatives in France. There is an urgent need to evaluate the safety of alternatives proposed to replace BPA as developer in thermal printing. The large proportion of samples with hormonal activity calls for the adoption of preventive measures.


Assuntos
Compostos Benzidrílicos/análise , Papel , Fenóis/análise , Sulfonas/análise , Brasil , Monitoramento Ambiental , Estrogênios , França , Humanos , Espanha
3.
PLoS One ; 13(2): e0192894, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29462174

RESUMO

Blood is a fluid connective tissue of human body, where it plays vital functions for the nutrition, defense and well-being of the organism. When circulating in peripheral districts, it is exposed to some physical stresses coming from outside the human body, as electromagnetic fields (EMFs) which can cross the skin. Such fields may interact with biomolecules possibly inducing non thermal-mediated biological effects at the cellular level. In this study, the occurrence of biochemical/biological modifications in human peripheral blood lympho-monocytes exposed in a reverberation chamber for times ranging from 1 to 20 h to EMFs at 1.8 GHz frequency and 200 V/m electric field strength was investigated. Morphological analysis of adherent cells unveiled, in some of these, appearance of an enlarged and deformed shape after EMFs exposure. Raman spectra of the nuclear compartment of cells exposed to EMFs revealed the onset of biochemical modifications, mainly consisting in the reduction of the DNA backbone-linked vibrational modes. Respirometric measurements of mitochondrial activity in intact lympho-monocytes resulted in increase of the resting oxygen consumption rate after 20 h of exposure, which was coupled to a significant increase of the FoF1-ATP synthase-related oxygen consumption. Notably, at lower time-intervals of EMFs exposure (i.e. 5 and 12 h) a large increase of the proton leak-related respiration was observed which, however, recovered at control levels after 20 h exposure. Confocal microscopy analysis of the mitochondrial membrane potential supported the respiratory activities whereas no significant variations in the mitochondrial mass/morphology was observed in EMFs-exposed lympho-monocytes. Finally, altered redox homeostasis was shown in EMFs-exposed lympho-monocytes, which progressed differently in nucleated cellular subsets. This results suggest the occurrence of adaptive mechanisms put in action, likely via redox signaling, to compensate for early impairments of the oxidative phosphorylation system caused by exposure to EMFs. Overall the data presented warn for health safety of people involved in long-term exposure to electromagnetic fields, although further studies are required to pinpoint the leukocyte cellular subset(s) selectively targeted by the EMFs action and the mechanisms by which it is achieved.


Assuntos
Campos Eletromagnéticos/efeitos adversos , Linfócitos/metabolismo , Linfócitos/efeitos da radiação , Monócitos/metabolismo , Monócitos/efeitos da radiação , Telefone Celular , Citrato (si)-Sintase/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Humanos , Linfócitos/patologia , Microscopia Confocal , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Monócitos/patologia , Espécies Reativas de Oxigênio/metabolismo , Análise Espectral Raman , Fatores de Tempo
4.
Br J Pharmacol ; 169(8): 1652-71, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23714011

RESUMO

UNLABELLED: Adult haematopoietic stem/progenitor cells (HSPCs) constitute the lifespan reserve for the generation of all the cellular lineages in the blood. Although massive progress in identifying the cluster of master genes controlling self-renewal and multipotency has been achieved in the past decade, some aspects of the physiology of HSPCs still need to be clarified. In particular, there is growing interest in the metabolic profile of HSPCs in view of their emerging role as determinants of cell fate. Indeed, stem cells and progenitors have distinct metabolic profiles, and the transition from stem to progenitor cell corresponds to a critical metabolic change, from glycolysis to oxidative phosphorylation. In this review, we summarize evidence, reported in the literature and provided by our group, highlighting the peculiar ability of HSPCs to adapt their mitochondrial oxidative/bioenergetic metabolism to survive in the hypoxic microenvironment of the endoblastic niche and to exploit redox signalling in controlling the balance between quiescence versus active cycling and differentiation. Especial prominence is given to the interplay between hypoxia inducible factor-1, globins and NADPH oxidases in managing the mitochondrial dioxygen-related metabolism and biogenesis in HSPCs under different ambient conditions. A mechanistic model is proposed whereby 'mitochondrial differentiation' is a prerequisite in uncommitted stem cells, paving the way for growth/differentiation factor-dependent processes. Advancing the understanding of stem cell metabolism will, hopefully, help to (i) improve efforts to maintain, expand and manipulate HSPCs ex vivo and realize their potential therapeutic benefits in regenerative medicine; (ii) reprogramme somatic cells to generate stem cells; and (iii) eliminate, selectively, malignant stem cells. LINKED ARTICLES: This article is part of a themed section on Emerging Therapeutic Aspects in Oncology. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.169.issue-8.


Assuntos
Células-Tronco Adultas/citologia , Células-Tronco Adultas/metabolismo , Mitocôndrias/metabolismo , Adulto , Diferenciação Celular , Linhagem da Célula , Metabolismo Energético , Glicólise , Humanos , Modelos Biológicos , Oxirredução , Fosforilação Oxidativa
6.
J Microsc ; 229(Pt 3): 517-24, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18331504

RESUMO

The aim of this study was to characterize the local distribution and organization of the plasma membrane NADPH-oxidase (NOX) in human haematopoietic stem cell (HSC) by means of the fluorescence scanning near-field optical microscopy approach. The presence of NOX in haematopoietic stem cells is thought to have a functional role as O(2) sensor and/or as low-level reactive oxygen species (ROS) producer to be used as redox messenger for controlling cell growth and differentiation. Given the harmful potential of ROS, a fine-tuning of NOX activity is needed. The high resolution imaging of haematopoietic stem cell membrane obtained in this study combined with the immunodetection of NOX indicates for this the occurrence of a cluster-organized structure. These membrane 'rafts'-like micro-compartments may constitute localized protein aggregates whereby the assembly/activation of the NOX components are functionally integrated with upstream factors constituting signal-transduction platforms.


Assuntos
Membrana Celular/enzimologia , Membrana Celular/ultraestrutura , Células-Tronco Hematopoéticas/enzimologia , Células-Tronco Hematopoéticas/ultraestrutura , NADPH Oxidases/análise , Células-Tronco Hematopoéticas/citologia , Humanos , Imuno-Histoquímica , Microscopia Confocal , Microscopia de Fluorescência , Microscopia de Varredura por Sonda , NADPH Oxidases/química
7.
Antioxid Redox Signal ; 8(3-4): 495-502, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16677093

RESUMO

A study is presented of the effect of the cAMP cascade on oxygen metabolism in mammalian cell cultures. Serum-starvation of the cell cultures resulted in depression of the forward NADH-ubiquinone oxidoreductase activity of complex I, decreased content of glutathione, and enhancement of the cellular level of H2O2. Depressed transcription of cytosolic Cu/Zn-SOD 1, mitochondrial glutathione peroxidase and catalase was also observed. Activation of the cAMP cascade reversed the depression of the activity of complex I and the accumulation of H2O2. The effect of cAMP involved the cAMP-dependent protein kinase.


Assuntos
AMP Cíclico/metabolismo , Radicais Livres , Oxigênio/química , Animais , Catalase/química , Proteínas Quinases Dependentes de AMP Cíclico/química , Citosol/enzimologia , Fibroblastos/metabolismo , Glutationa Peroxidase/química , Humanos , Peróxido de Hidrogênio/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Células NIH 3T3 , Espécies Reativas de Oxigênio , Superóxido Dismutase/química
8.
Phys Med Biol ; 50(10): 2241-8, 2005 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-15876664

RESUMO

The compound probability density function (pdf) is investigated for the ability of its parameters to classify masses in ultrasonic B scan breast images. Results of 198 images (29 malignant and 70 benign cases and two images per case) are reported and compared to the classification performance reported by us earlier in this journal. A new parameter, the speckle factor, calculated from the parameters of the compound pdf was explored to separate benign and malignant masses. The receiver operating characteristic curve for the parameter resulted in an A(z) value of 0.852. This parameter was combined with one of the parameters from our previous work, namely the ratio of the K distribution parameter at the site and away from the site. This combined parameter resulted in an A(z) value of 0.955. In conclusion, the parameters of the K distribution and the compound pdf may be useful in the classification of breast masses. These parameters can be calculated in an automated fashion. It should be possible to combine the results of the ultrasonic image analysis with those of traditional mammography, thereby increasing the accuracy of breast cancer diagnosis.


Assuntos
Algoritmos , Inteligência Artificial , Neoplasias da Mama/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Modelos Biológicos , Neoplasias da Mama/classificação , Análise por Conglomerados , Feminino , Humanos , Modelos Estatísticos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Distribuições Estatísticas , Ultrassonografia
9.
Ultrasound Med Biol ; 28(10): 1295-300, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12467856

RESUMO

Classification of masses in ultrasonic B-mode images of the breast tissue using "normalized" parameters of the Nakagami distribution was recently investigated. The technique, however, did not yield performances that were comparable to those of an experienced radiologist, and utilized only a single image for tissue characterization. Because radiologists commonly use two to four images of a mass for characterization, a similar procedure is developed here. A simple summation of the normalized Nakagami parameters from two different images of a mass is utilized for classification as benign or malignant. The performance of the normalized Nakagami parameters before and after the summation has been carried out through a receiver operating characteristic (ROC) study. The bootstrap procedure has been utilized to compute the mean and SD of the ROC area, A(z), obtained for each parameter. It has been observed that combining normalized Nakagami parameters from two images of the mass may help to improve classification performance over that from utilizing the parameters of just a single image. The performance of this automated parameter-based approach appears to match that of a trained radiologist.


Assuntos
Algoritmos , Neoplasias da Mama/diagnóstico por imagem , Ultrassonografia Mamária , Neoplasias da Mama/classificação , Diagnóstico Diferencial , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Curva ROC , Sensibilidade e Especificidade
10.
Med Phys ; 29(9): 1968-73, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12349916

RESUMO

Frequency compounding was recently investigated for computer aided classification of masses in ultrasonic B-mode images as benign or malignant. The classification was performed using the normalized parameters of the Nakagami distribution at a single region of interest at the site of the mass. A combination of normalized Nakagami parameters from two different images of a mass was undertaken to improve the performance of classification. Receiver operating characteristic (ROC) analysis showed that such an approach resulted in an area of 0.83 under the ROC curve. The aim of the work described in this paper is to see whether a feature describing the characteristic of the boundary can be extracted and combined with the Nakagami parameter to further improve the performance of classification. The combination of the features has been performed using a weighted summation. Results indicate a 10% improvement in specificity at a sensitivity of 96% after combining the information at the site and at the boundary. Moreover, the technique requires minimal clinical intervention and has a performance that reaches that of the trained radiologist. It is hence suggested that this technique may be utilized in practice to characterize breast masses.


Assuntos
Neoplasias da Mama/classificação , Neoplasias da Mama/diagnóstico por imagem , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Ultrassonografia Mamária/métodos , Humanos , Modelos Biológicos , Modelos Estatísticos , Controle de Qualidade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
11.
Artigo em Inglês | MEDLINE | ID: mdl-12046943

RESUMO

The parameters of the Nakagami distribution have been utilized in the past to classify lesions in breast tissue as benign or malignant. To avoid the effect of operatorgain settings on the parameters of the Nakagami distribution, normalized parameters were utilized for the classification. The normalized parameter was defined as the ratio of the parameter at the site of the lesion to its average value over several regions away from the site. This technique, however, was very time consuming. In this paper, the application of frequency diversity and compounding is explored to achieve this normalization. Lesions are classified using these normalized parameters at the site. A receiver operating characteristic (ROC) analysis of the parameters of the Nakagami distribution has been conducted before and after compounding on a data set of 60 benign and 65 malignant lesions. The ROC results indicate that this technique can reasonably classify lesions in breast tissue as benign or malignant.


Assuntos
Neoplasias da Mama/classificação , Neoplasias da Mama/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Modelos Estatísticos , Biópsia , Neoplasias da Mama/patologia , Humanos , Aumento da Imagem/métodos , Curva ROC , Espalhamento de Radiação , Sensibilidade e Especificidade , Ultrassonografia
12.
Ultrasound Med Biol ; 27(11): 1505-14, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11750750

RESUMO

This paper presents performance comparisons between breast tumor classifiers based on parameters from a conventional texture analysis (CTA) and the generalized spectrum (GS). The computations of GS-based parameters from radiofrequency (RF) ultrasonic scans and their relationship to underlying scatterer properties are described. Clinical experiments demonstrate classifier performances using 22 benign and 24 malignant breast mass regions taken from 40 patients. Linear classifiers based on parameters from the front edge, back edge and interior tumor regions are examined. Results show significantly better performances for GS-based classifiers, with improvements in empirical receiver operating characteristic (ROC) areas of greater than 10%. The ROC curves show GS-based classifiers achieving a 90% sensitivity level at 50% specificity when applied to the back-edge tumor regions, an 80% sensitivity level at 65% specificity when applied to the front-edge tumor regions, and a 100% sensitivity level at 45% specificity when applied to the interior tumor regions.


Assuntos
Neoplasias da Mama/classificação , Neoplasias da Mama/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Ultrassonografia Mamária/métodos , Diagnóstico Diferencial , Feminino , Humanos , Curva ROC , Sensibilidade e Especificidade
13.
Magn Reson Imaging Clin N Am ; 9(2): 393-408, vii-viii, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11493428

RESUMO

There are two reasons for radiologic evaluation of the augmented breast. Because women with implants are at the same risk for breast cancer as other women, imaging is performed to screen for cancer or to work up clinical abnormalities. Additionally, imaging allows assessment of implant integrity. The various methods for imaging implants and breast tissue in the augmented patient are discussed. Imaging findings suggestive of silicone gel implant rupture are presented.


Assuntos
Implantes de Mama , Imageamento por Ressonância Magnética/métodos , Neoplasias da Mama/diagnóstico , Feminino , Géis , Humanos , Mamografia , Falha de Prótese , Sensibilidade e Especificidade , Silicones , Ultrassonografia Mamária
14.
Artigo em Inglês | MEDLINE | ID: mdl-11477787

RESUMO

We propose a new model for the RF ultrasound echo, namely the power-law shot-noise process. Based on this model, the in-phase and quadrature components of the echo are shown to exhibit 1/f beta-type spectral behavior, in a sense that is defined in the paper. The envelope also exhibits this type of spectral behavior, but with a different exponent. This result explains the experimental observations by other researchers of the power-law trend of the RF echo spectrum. Although the shot-noise model has been used in the past for modeling the RF echo, this is the first time that a power-law impulse response filter is used and that the resulting 1/f beta-type spectral behavior of the RF echo has been investigated. The model parameters are linked to tissue characteristics, such as scatterer density and attenuation; thus, they have the potential to be used as tissue characterization features. The validity of the proposed model is tested based on a database of 100 clinical ultrasound images of the breast.


Assuntos
Modelos Teóricos , Ondas de Rádio , Ultrassonografia/estatística & dados numéricos , Engenharia Biomédica , Simulação por Computador , Bases de Dados Factuais , Feminino , Humanos , Método de Monte Carlo , Ultrassonografia Mamária/estatística & dados numéricos
15.
Eur J Clin Invest ; 31(7): 628-38, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11454019

RESUMO

Cryoglobulins are cold-precipitable immunoglobulins associated with a number of infectious, autoimmune and neoplastic disorders. Their appearance along with rheumatoid factor (RF) can be considered a normal event in the clearance of immune complexes and rarely produces any symptoms. The association between hepatitis C virus (HCV) and mixed cryoglobulinemia (MC) has been rendered evident since the recognition of serological markers of HCV infection. There is thus every reason to suppose that direct or indirect involvement of B cells on the part of the HCV results in their persistent stimulation, clonal expansion and release of molecules with RF activity. The formation of RF/IgG immune complexes is the key pathogenetic mechanism. The close correlation between HCV infection and MC also throws new light on the interpretation of autoimmune phenomena in the course of viral infection and on the close link between autoimmune diseases and lymphoproliferative disorders. The higher risk of non-Hodgkin's lymphoma (NHL) displayed by HCV positive subjects, especially in the Mediterranean basin, suggests that the HCV's chronic lymphoproliferative drive may progress towards frank lymphoid neoplasia. The presence of MC does not represent an in situ or 'occult' NHL, because recent evidences indicate that none of the clones interpreted as predominant displays the molecular features of a true neoplastic process. The cryoglobulinemic syndrome is probably the consequence of pathogenic noxae that act upon the immune system of a host in which regulation of the peripheral T cell response appears to be in some way altered.


Assuntos
Crioglobulinemia/diagnóstico , Crioglobulinemia/etiologia , Crioglobulinas/análise , Hepatite C/complicações , Transtornos Linfoproliferativos/etiologia , Crioglobulinemia/terapia , Humanos , Linfoma não Hodgkin/etiologia , Síndrome , Vasculite
16.
J Immunol ; 167(1): 21-9, 2001 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-11418627

RESUMO

PCR DNA amplification of IgH genes was performed on liver biopsy samples of 42 unselected hepatitis C virus (HCV)-positive patients. Genotypic analysis and signal amplification by branched DNA were used to characterize and quantitate HCV RNA genomic sequences. Intraportal lymphoid follicle-like structures were isolated from surrounding hepatocytes by microdissection technique. IgH VDJ PCR products were cloned and sequenced. IgH VDJ gene rearrangements were detected in the liver of 26 (62%) patients. Unequivocal monoclonal or oligoclonal patterns of B cell expansions were found in 14 (33.3%) and 12 (28.6%) patients, respectively. Patients with intrahepatic B cell monoclonal expansions showed liver HCV RNA levels higher than those with oligoclonal or polyclonal features (1106.4 +/- 593.5 vs 677.3 +/- 424.3 vs 406.2 +/- 354.3 pg HCV RNA/g tissue; p = 0.048 and p = 0.001, respectively). Although a single dominant band was obtained with total DNA, characterization of DNA recovered from intraportal inflammatory aggregates resulted in the detection of multiple IgH VDJ gene rearrangements, pointing to an oligoclonal pattern of lymphoproliferation. Cloning and sequence analyses showed that B cell clonalities were differently distributed in adjacent portal tracts of the same liver area. In addition, HCV RNA genomic sequences could be consistently amplified from each of the portal inflammatory aggregates examined. These data support the concept that in chronic HCV infection the intrahepatic B cell repertoire is frequently clonally restricted and that HCV may have a direct role in sustaining in situ B cell proliferation.


Assuntos
Linfócitos B/imunologia , Hepatite C Crônica/imunologia , Fígado/imunologia , Fígado/patologia , Adulto , Idoso , Linfócitos B/patologia , Linfócitos B/virologia , Sequência de Bases , Agregação Celular/imunologia , Diferenciação Celular/imunologia , Células Clonais , Clonagem Molecular , Feminino , Mutação em Linhagem Germinativa , Hepatite C Crônica/patologia , Hepatite C Crônica/virologia , Humanos , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Sistema Porta/imunologia , Sistema Porta/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Carga Viral
17.
Artigo em Inglês | MEDLINE | ID: mdl-11370350

RESUMO

In the first part of this work [16], a wavelet-based decomposition algorithm of the RF echo into its coherent and diffuse components was introduced. In this paper, the proposed algorithm is used to estimate structural parameters of the breast tissue such as the number and energy of coherent scatterers, the energy of the diffuse scatterers, and the correlation between them. Based on these individual parameters, breast tissue characterization is performed. The database used consists of 155 breast scans from 42 patients. The results are presented in terms of empirical receiver operating characteristics (ROC) curves. The results of this study are discussed in relation to the tissue microstructure. Individual estimated parameters are able to differentiate reliably between normal and fibroadenoma or fibrocystic or cancerous tissue (area under the ROC Az > 0.93). Also, the differentiation between malignant and benign (normal, fibrocystic, and fibroadenoma) tissue was possible (Az > 0.89).


Assuntos
Ultrassonografia Mamária , Algoritmos , Engenharia Biomédica , Neoplasias da Mama/diagnóstico por imagem , Carcinoma Ductal de Mama/diagnóstico por imagem , Feminino , Fibroadenoma/diagnóstico por imagem , Doença da Mama Fibrocística/diagnóstico por imagem , Humanos , Curva ROC , Ondas de Rádio , Espalhamento de Radiação , Ultrassonografia Mamária/estatística & dados numéricos
18.
Artigo em Inglês | MEDLINE | ID: mdl-11370371

RESUMO

The Nakagami distribution was proposed recently for modeling the echo from tissue. In vivo breast data collected from patients with lesions were studied using this Nakagami model. Chi-square tests showed that the Nakagami distribution is a better fit to the envelope than the Rayleigh distribution. Two parameters, m (effective number) and alpha (effective cross section), associated with the Nakagami distribution were used for the classification of breast masses. Data from 52 patients with breast masses/lesions were used in the studies. Receiver operating characteristics (ROC) were calculated for the classification methods based on these two parameters. The results indicate that these parameters of the Nakagami distribution may be useful in classification of the breast abnormalities. The Nakagami distribution may be a reasonable means to characterize the backscattered echo from breast tissues toward a goal of an automated scheme for separating benign and malignant breast masses.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Ultrassonografia Mamária/métodos , Acústica , Engenharia Biomédica , Neoplasias da Mama/classificação , Distribuição de Qui-Quadrado , Diagnóstico por Computador , Diagnóstico Diferencial , Feminino , Humanos , Modelos Teóricos , Curva ROC , Espalhamento de Radiação , Ultrassonografia Mamária/estatística & dados numéricos
19.
Radiology ; 219(2): 495-7, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11323477

RESUMO

A 53-year-old woman with right breast microcalcifications of intermediate concern underwent stereotactic directional vacuum-assisted biopsy with marking clip placement. Postbiopsy mammograms showed displacement of a few of the targeted microcalcifications adjacent to misplaced marker clips. Mammography following stereotactic breast biopsy is important to document the location and number of residual calcifications and to determine the adequacy and location of clip placement.


Assuntos
Biópsia , Doenças Mamárias/patologia , Mama/patologia , Calcinose/patologia , Mamografia , Biópsia/métodos , Doenças Mamárias/diagnóstico por imagem , Calcinose/diagnóstico por imagem , Feminino , Humanos , Pessoa de Meia-Idade , Técnicas Estereotáxicas , Vácuo
20.
Semin Liver Dis ; 20(2): 143-57, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10946420

RESUMO

Like other hepatotropic viruses, hepatitis C virus (HCV) shares the property of inducing hepatocellular damage, possibly through induction of immune mechanisms that lead to hepatocellular necrosis. After infection of hepatocytes, and possibly other cells, humoral and cellular responses occur aimed at prevention of virus dissemination and elimination of infected cells. The early activated mechanisms include production of nonspecific and specific antibodies that represent the first-line of defense against invading foreign pathogens. As a consequence, circulating immune complexes are promptly formed, and antigen uptake and processing by specialized cells are enhanced. A major fraction of circulating immunoglobulins (Igs) are part of the spectrum of the so-called natural antibodies, which include anti-idiotypic antibodies and molecules with rheumatoid factor (RF) activity. They mainly belong to the IgM class, are polyclonal, and have no intrinsic pathogenetic potential. In 20-30% of HCV-infected patients, RFs share characteristics of high affinity molecules, are monoclonal in nature, and result in the production of cold-precipitating immune complexes and mixed cryoglobulinemia. It has been shown that anti-idiotypic antibodies and polyclonal and monoclonal RF molecules have the same cross-reactive idiotype, called WA, suggesting that their production is highly restricted. This strongly indicates that they arise from stimulation with the same antigen, likely HCV. It has also been speculated that B-1 (CD5+) and B-2 (CD5-) B-cell subsets, which use a limited number of VH germline genes, underlie the production of low-affinity polyclonal and high-affinity monoclonal antibodies, respectively. The persistent production of monoclonal RF molecules implies the existence of a further mechanism capable of restricting the reactivity and reflects a distinct selection of a cell population that can be maintained throughout life because they are continuously exposed to antigen pressure. Either polyclonal or monoclonal profiles of B-cell expansion are demonstrable in the liver of most HCV-infected patients. The occurrence of B-cell clonal expansion is strictly related to intrahepatic production of RF molecules, and this suggests that liver is a microenvironment, other than lymphoid tissue, in which a germinal centerlike reaction is induced. The frequent detection of oligoclonal B-cell expansion may, indeed, represent a key pathobiologic feature that sustains nonmalignant B-cell lymphoproliferation. The preferential expansion of one clone would in turn lead to a monoclonal pattern that could favor stochastic oncogenic events. It can be postulated that HCV is the stimulus not only for the apparent benign lymphoproliferative process underlying a wide spectrum of clinical features, but also for the progression to frank lymphoid malignancy in a subgroup of patients. Current data indicate a higher prevalence of overt B-cell non-Hodgkin's lymphoma in HCV-infected patients, especially in some geographic areas.


Assuntos
Autoimunidade/imunologia , Crioglobulinemia/imunologia , Hepacivirus/imunologia , Hepatite C/imunologia , Fígado/imunologia , Linfoma de Células B/imunologia , Divisão Celular , Crioglobulinemia/fisiopatologia , Hepatite C/fisiopatologia , Humanos , Fígado/citologia , Linfoma de Células B/etiologia , Fator Reumatoide/biossíntese
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