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1.
Braz. J. Anesth. (Impr.) ; 73(3): 340-343, May-June 2023. graf
Artigo em Inglês | LILACS | ID: biblio-1439616

RESUMO

Abstract The prone position is extensively used to improve oxygenation in patients with severe acute respiratory distress syndrome caused by SARS-CoV-2 pneumonia. Occasionally, these patients exhibit cardiac and respiratory functions so severely compromised they cannot tolerate lying in the supine position, not even for the time required to insert a central venous catheter. The authors describe three cases of successful ultrasound-guided internal jugular vein cannulation in prone position. The alternative approach here described enables greater safety and well-being for the patient, reduces the number of episodes of decompensation, and risk of tracheal extubation and loss of in-situ vascular lines.


Assuntos
Humanos , Cateterismo Venoso Central , COVID-19/complicações , Decúbito Ventral , Ultrassonografia de Intervenção , COVID-19 , Unidades de Terapia Intensiva
2.
Braz J Anesthesiol ; 73(3): 340-343, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-34843804

RESUMO

The prone position is extensively used to improve oxygenation in patients with severe acute respiratory distress syndrome caused by SARS-CoV-2 pneumonia. Occasionally, these patients exhibit cardiac and respiratory functions so severely compromised they cannot tolerate lying in the supine position, not even for the time required to insert a central venous catheter. The authors describe three cases of successful ultrasound-guided internal jugular vein cannulation in prone position. The alternative approach here described enables greater safety and well-being for the patient, reduces the number of episodes of decompensation, and risk of tracheal extubation and loss of in-situ vascular lines.


Assuntos
COVID-19 , Cateterismo Venoso Central , Humanos , Ultrassonografia de Intervenção , Decúbito Ventral , COVID-19/complicações , SARS-CoV-2 , Unidades de Terapia Intensiva
3.
Med Image Anal ; 52: 160-173, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30580111

RESUMO

Object segmentation and structure localization are important steps in automated image analysis pipelines for microscopy images. We present a convolution neural network (CNN) based deep learning architecture for segmentation of objects in microscopy images. The proposed network can be used to segment cells, nuclei and glands in fluorescence microscopy and histology images after slight tuning of input parameters. The network trains at multiple resolutions of the input image, connects the intermediate layers for better localization and context and generates the output using multi-resolution deconvolution filters. The extra convolutional layers which bypass the max-pooling operation allow the network to train for variable input intensities and object size and make it robust to noisy data. We compare our results on publicly available data sets and show that the proposed network outperforms recent deep learning algorithms.


Assuntos
Técnicas Histológicas/métodos , Processamento de Imagem Assistida por Computador/métodos , Microscopia de Fluorescência , Redes Neurais de Computação , Algoritmos , Animais , Humanos
4.
Kidney Int ; 90(2): 300-310, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27165837

RESUMO

Recent work demonstrates that Alport glomerular disease is mediated through a biomechanical strain-sensitive activation of mesangial actin dynamics. This occurs through a Rac1/CDC42 cross-talk mechanism that results in the invasion of the subcapillary spaces by mesangial filopodia. The filopodia deposit mesangial matrix proteins in the glomerular basement membrane, including laminin 211, which activates focal adhesion kinase in podocytes culminating in the up-regulation of proinflammatory cytokines and metalloproteinases. These events drive the progression of glomerulonephritis. Here we test whether endothelial cell-derived endothelin-1 is up-regulated in Alport glomeruli and further elevated by hypertension. Treatment of cultured mesangial cells with endothelin-1 activates the formation of drebrin-positive actin microspikes. These microspikes do not form when cells are treated with the endothelin A receptor antagonist sitaxentan or under conditions of small, interfering RNA knockdown of endothelin A receptor mRNA. Treatment of Alport mice with sitaxentan results in delayed onset of proteinuria, normalized glomerular basement membrane morphology, inhibition of mesangial filopodial invasion of the glomerular capillaries, normalization of glomerular expression of metalloproteinases and proinflammatory cytokines, increased life span, and prevention of glomerulosclerosis and interstitial fibrosis. Thus endothelin A receptor activation on mesangial cells is a key event in initiation of Alport glomerular disease in this model.


Assuntos
Endotelina-1/metabolismo , Células Mesangiais/metabolismo , Nefrite Hereditária/metabolismo , Podócitos/metabolismo , Receptor de Endotelina A/metabolismo , Animais , Fenômenos Biomecânicos , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Antagonistas dos Receptores de Endotelina/farmacologia , Antagonistas dos Receptores de Endotelina/uso terapêutico , Imunofluorescência , Técnicas de Silenciamento de Genes , Membrana Basal Glomerular/metabolismo , Hipertensão/metabolismo , Isoxazóis/farmacologia , Isoxazóis/uso terapêutico , Laminina/metabolismo , Células Mesangiais/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Nefrite Hereditária/genética , Proteinúria/tratamento farmacológico , Pseudópodes/fisiologia , Interferência de RNA , RNA Interferente Pequeno/genética , Receptor de Endotelina A/genética , Transdução de Sinais , Tiofenos/farmacologia , Tiofenos/uso terapêutico , Regulação para Cima
5.
Eur J Psychol ; 11(3): 459-75, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27247670

RESUMO

Psychobiography holds an important position in the history of psychology, yet little is known about the status of psychobiographical training and dissertation research in psychology departments. This brief report identified psychobiography courses throughout North America and content analyzed a sample of 65 psychobiography dissertations to discern the theories and methods that have most commonly anchored this research. Results identified few psychology courses specifically in psychobiography, with a larger number of courses incorporating psychobiographical and/or narrative elements. With regard to psychobiography dissertations, the majority focused on artists, pioneering psychologists, and political leaders. Theories undergirding psychobiographical studies were most frequently psychoanalytic and psychodynamic. Methodologically, a majority of the dissertations were anchored in constructivist (discovery-oriented) qualitative procedures, with a minority incorporating mixed methods designs. The authors highlight the value of psychobiographical training to psychology students and present avenues and models for incorporating psychobiography into psychology curriculums.

6.
PLoS One ; 9(4): e94272, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24705452

RESUMO

Usher syndrome type 1B is a combined deaf-blindness condition caused by mutations in the MYO7A gene. Loss of functional myosin VIIa in the retinal pigment epithelia (RPE) and/or photoreceptors leads to blindness. We evaluated the impact of subretinally delivered UshStat, a recombinant EIAV-based lentiviral vector expressing human MYO7A, on photoreceptor function in the shaker1 mouse model for Usher type 1B that lacks a functional Myo7A gene. Subretinal injections of EIAV-CMV-GFP, EIAV-RK-GFP (photoreceptor specific), EIAV-CMV-MYO7A (UshStat) or EIAV-CMV-Null (control) vectors were performed in shaker1 mice. GFP and myosin VIIa expression was evaluated histologically. Photoreceptor function in EIAV-CMV-MYO7A treated eyes was determined by evaluating α-transducin translocation in photoreceptors in response to low light intensity levels, and protection from light induced photoreceptor degeneration was measured. The safety and tolerability of subretinally delivered UshStat was evaluated in macaques. Expression of GFP and myosin VIIa was confirmed in the RPE and photoreceptors in shaker1 mice following subretinal delivery of the EIAV-CMV-GFP/MYO7A vectors. The EIAV-CMV-MYO7A vector protected the shaker1 mouse photoreceptors from acute and chronic intensity light damage, indicated by a significant reduction in photoreceptor cell loss, and restoration of the α-transducin translocation threshold in the photoreceptors. Safety studies in the macaques demonstrated that subretinal delivery of UshStat is safe and well-tolerated. Subretinal delivery of EIAV-CMV-MYO7A (UshStat) rescues photoreceptor phenotypes in the shaker1 mouse. In addition, subretinally delivered UshStat is safe and well-tolerated in macaque safety studies These data support the clinical development of UshStat to treat Usher type 1B syndrome.


Assuntos
Terapia Genética , Vetores Genéticos/genética , Vírus da Anemia Infecciosa Equina/genética , Síndromes de Usher/genética , Síndromes de Usher/terapia , Animais , Linhagem Celular , Modelos Animais de Doenças , Feminino , Ordem dos Genes , Vetores Genéticos/administração & dosagem , Vetores Genéticos/metabolismo , Humanos , Macaca , Masculino , Camundongos , Camundongos Knockout , Miosina VIIa , Miosinas/genética , Fenótipo , Células Fotorreceptoras/metabolismo , Células Fotorreceptoras/patologia , Transporte Proteico , Retina/metabolismo , Retina/patologia , Transducina/metabolismo
7.
Exp Eye Res ; 118: 145-53, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24211856

RESUMO

Usher syndrome combines congenital hearing loss and retinitis pigmentosa (RP). Mutations in the whirlin gene (DFNB31/WHRN) cause a subtype of Usher syndrome (USH2D). Whirler mice have a defective whirlin gene. They have inner ear defects but usually do not develop retinal degeneration. Here we report that, in whirler mouse photoreceptors, the light-activated rod transducin translocation is delayed and its activation threshold is shifted to a higher level. Rhodopsin mis-localization is observed in rod inner segments. Continuous moderate light exposure can induce significant rod photoreceptor degeneration. Whirler mice reared under a 1500 lux light/dark cycle also develop severe photoreceptor degeneration. Previously, we have reported that shaker1 mice, a USH1B model, show moderate light-induced photoreceptor degeneration with delayed transducin translocation. Here, we further show that, in both whirler and shaker1 mice, short-term moderate light/dark changes can induce rod degeneration as severe as that induced by continuous light exposure. The results from shaker1 and whirler mice suggest that defective transducin translocation may be functionally related to light-induced degeneration, and these two symptoms may be caused by defects in Usher protein function in rods. Furthermore, these results indicate that both Usher syndrome mouse models possess a light-induced retinal phenotype and may share a closely related pathobiological mechanism.


Assuntos
Adaptação Ocular/fisiologia , Degeneração Retiniana/genética , Células Fotorreceptoras Retinianas Bastonetes/fisiologia , Transducina/genética , Translocação Genética , Animais , Western Blotting , Contagem de Células , Imuno-Histoquímica , Masculino , Camundongos , Fotoperíodo , Degeneração Retiniana/patologia , Degeneração Retiniana/fisiopatologia , Transducina/metabolismo
8.
Pharmacotherapy ; 33(8): 856-67, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23712569

RESUMO

As the progression of multidrug-resistant organisms and lack of novel antibiotics move us closer toward a potential postantibiotic era, it is paramount to preserve the longevity of current therapeutic agents. Moreover, novel interventions for antimicrobial stewardship programs are integral to combating antimicrobial resistance worldwide. One unique method that may decrease the use of second-line antibiotics (e.g., fluoroquinolones, vancomycin) while facilitating access to a preferred ß-lactam regimen in numerous health care settings is a penicillin skin test. Provided that up to 10% of patients have a reported penicillin allergy, of whom ~10% have true IgE-mediated hypersensitivity, significant potential exists to utilize a penicillin skin test to safely identify those who may receive penicillin or a ß-lactam antibiotic. In this article, we provide information on the background, associated costs, currently available literature, pharmacists' role, antimicrobial stewardship implications, potential barriers, and misconceptions, as well as future directions associated with the penicillin skin test.


Assuntos
Antibacterianos/efeitos adversos , Hipersensibilidade a Drogas/fisiopatologia , Penicilinas/efeitos adversos , Testes Cutâneos/métodos , Hipersensibilidade a Drogas/economia , Hipersensibilidade a Drogas/história , Serviço Hospitalar de Emergência , História do Século XX , Humanos , Unidades de Terapia Intensiva , Farmacêuticos , Testes Cutâneos/economia
9.
PLoS One ; 7(12): e49394, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23251341

RESUMO

Influenza A viruses are a major cause of morbidity and mortality in the human population, causing epidemics in the winter, and occasional worldwide pandemics. In addition there are periodic outbreaks in domestic poultry, horses, pigs, dogs, and cats. Infections of domestic birds can be fatal for the birds and their human contacts. Control in man operates through vaccines and antivirals, but both have their limitations. In the search for an alternative treatment we have focussed on defective interfering (DI) influenza A virus. Such a DI virus is superficially indistinguishable from a normal virus but has a large deletion in one of the eight RNAs that make up the viral genome. Antiviral activity resides in the deleted RNA. We have cloned one such highly active DI RNA derived from segment 1 (244 DI virus) and shown earlier that intranasal administration protects mice from lethal disease caused by a number of different influenza A viruses. A more cogent model of human influenza is the ferret. Here we found that intranasal treatment with a single dose of 2 or 0.2 µg 244 RNA delivered as A/PR/8/34 virus particles protected ferrets from disease caused by pandemic virus A/California/04/09 (A/Cal; H1N1). Specifically, 244 DI virus significantly reduced fever, weight loss, respiratory symptoms, and infectious load. 244 DI RNA, the active principle, was amplified in nasal washes following infection with A/Cal, consistent with its amelioration of clinical disease. Animals that were treated with 244 DI RNA cleared infectious and DI viruses without delay. Despite the attenuation of infection and disease by DI virus, ferrets formed high levels of A/Cal-specific serum haemagglutination-inhibiting antibodies and were solidly immune to rechallenge with A/Cal. Together with earlier data from mouse studies, we conclude that 244 DI virus is a highly effective antiviral with activity potentially against all influenza A subtypes.


Assuntos
Vírus Defeituosos/imunologia , Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Animais , Vírus Defeituosos/genética , Furões , Vírus da Influenza A/genética , Vacinas contra Influenza/genética , Infecções por Orthomyxoviridae/imunologia , Pandemias
10.
Antiviral Res ; 96(3): 376-85, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23041142

RESUMO

The main antivirals employed to combat seasonal and pandemic influenza are oseltamivir and zanamivir which act by inhibiting the virus-encoded neuraminidase. These have to be deployed close to the time of infection and antiviral resistance to the more widely used oseltamivir has arisen relatively rapidly. Defective interfering (DI) influenza virus is a natural antiviral that works in a different way to oseltamivir and zanamivir, and a cloned version (segment 1 244 DI RNA in a cloned A/PR/8/34 virus; 244/PR8) has proved effective in preclinical studies in mice. The active principle is the DI RNA, and this is thought to interact with all influenza A viruses by inhibiting RNA virus synthesis and packaging of the cognate virion RNA into nascent DI virus particles. We have compared the ability of DI virus and oseltamivir to protect ferrets from intranasal 2009 pandemic influenza virus A/California/04/09 (A/Cal, H1N1). Ferrets were treated with a single 2 µg intranasal dose of 244 DI RNA delivered as 244/PR8 virus, or a total of 25mg/kg body weight of oseltamivir given as 10 oral doses over 5 days. Both DI virus and oseltamivir reduced day 2 infectivity and the influx of cells into nasal fluids, and permitted the development of adaptive immunity. However DI virus, but not oseltamivir, significantly reduced weight loss, facilitated better weight gain, reduced respiratory disease, and reduced infectivity on days 4 and 6. 244 DI RNA was amplified by A/Cal by >25,000-fold, consistent with the amelioration of clinical disease. Treatment with DI virus did not delay clearance or cause persistence of infectious virus or DI RNA. Thus in this system DI virus was overall more effective than oseltamivir in combatting pandemic A/California/04/09.


Assuntos
Vírus Defeituosos/imunologia , Furões/virologia , Vírus da Influenza A Subtipo H1N1/patogenicidade , Infecções por Orthomyxoviridae/prevenção & controle , Oseltamivir/farmacologia , Animais , Antivirais/farmacologia , Linhagem Celular , Furões/imunologia , Testes de Inibição da Hemaglutinação , Vírus da Influenza A Subtipo H1N1/imunologia , Masculino , Líquido da Lavagem Nasal/virologia , Infecções por Orthomyxoviridae/tratamento farmacológico , Infecções por Orthomyxoviridae/imunologia , RNA Viral/imunologia , Transfecção , Redução de Peso
11.
Islets ; 2(1): 37-45, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-21099292

RESUMO

c-Myc (Myc) is a mediator of glucotoxicity but could also independently compromise ß-cell survival and function. We have shown that after Myc activation in adult ß-cells in vivo, apoptosis is preceded by hyperglycemia, suggesting glucotoxicity might contribute to Myc-induced apoptosis. To address this question conditional Myc was activated in ß-cells of adult pIns-c-MycER(TAM) mice in vivo in the presence or absence of various glucose-lowering treatments, including exogenous insulin and prior to transplantation with wild-type islets. Changes in blood glucose levels were subsequently correlated with changes in ß-cell mass and markers of function/differentiation. Activation of c-Myc resulted in reduced insulin secretion, hyperglycemia and loss of ß-cell differentiation, followed by reduction in mass. Glucose-lowering interventions did not prevent loss of ß-cells. Therefore, Myc can cause diabetes by direct effects on ß-cell apoptosis even in the absence of potentially confounding secondary hyperglycemia. Moreover, as loss of ß-cell differentiation/function and hyperglycemia are not prevented by preventing ß-cell apoptosis, we conclude that Myc might contribute to the pathogenesis of diabetes by directly coupling cell cycle entry and ß-cell failure through two distinct pathways.


Assuntos
Genes myc/fisiologia , Hiperglicemia/metabolismo , Hiperglicemia/patologia , Células Secretoras de Insulina/citologia , Insulina/metabolismo , Animais , Contagem de Células , Ciclo Celular/genética , Ciclo Celular/fisiologia , Diferenciação Celular/genética , Feminino , Hiperglicemia/genética , Hiperglicemia/fisiopatologia , Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Transgênicos , Tamanho do Órgão/genética , Pâncreas/metabolismo , Pâncreas/patologia , Transgenes/fisiologia , Regulação para Cima
12.
Kidney Int ; 76(9): 968-76, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19710627

RESUMO

Patients with Alport's syndrome develop a number of pro-inflammatory cytokine and matrix metalloproteinase (MMP) abnormalities that contribute to progressive renal failure. Changes in the composition and structure of the glomerular basement membranes likely alter the biomechanics of cell adhesion and signaling in these patients. To test if enhanced strain on the capillary tuft due to these structural changes contributes to altered gene regulation, we subjected cultured podocytes to cyclic biomechanical strain. There was robust induction of interleukin (IL)-6, along with MMP-3, -9, -10, and -14, but not MMP-2 or -12 by increased strain. Neutralizing antibodies against IL-6 attenuated the strain-mediated induction of MMP-3 and -10. Alport mice treated with a general inhibitor of nitric oxide synthase (L-NAME) developed significant hypertension and increased IL-6 and MMP-3 and -10 in their glomeruli relative to those of normotensive Alport mice. These hypertensive Alport mice also had elevated proteinuria along with more advanced histological and ultrastructural glomerular basement membrane damage. We suggest that MMP and cytokine dysregulation may constitute a maladaptive response to biomechanical strain in the podocytes of Alport patients, thus contributing to glomerular disease initiation and progression.


Assuntos
Membrana Basal Glomerular/metabolismo , Interleucina-6/genética , Glomérulos Renais/metabolismo , Metaloproteinases da Matriz/genética , Nefrite Hereditária/genética , Podócitos/metabolismo , Adaptação Fisiológica/genética , Animais , Pressão Sanguínea , Células Cultivadas , Citoesqueleto/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica , Hipertensão/induzido quimicamente , Hipertensão/genética , Hipertensão/fisiopatologia , Interleucina-6/metabolismo , Glomérulos Renais/fisiopatologia , Metaloproteinase 10 da Matriz/genética , Metaloproteinase 14 da Matriz/genética , Metaloproteinase 3 da Matriz/genética , Metaloproteinase 9 da Matriz/genética , Metaloproteinases da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , NG-Nitroarginina Metil Éster , Nefrite Hereditária/metabolismo , Nefrite Hereditária/fisiopatologia , Proteinúria/induzido quimicamente , Proteinúria/genética , Proteinúria/fisiopatologia , RNA Mensageiro/metabolismo , Cloreto de Sódio na Dieta , Estresse Mecânico , Fatores de Tempo
13.
J Agric Food Chem ; 54(13): 4658-67, 2006 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-16787012

RESUMO

Substrates from three mushroom compost facilities in Northern Ireland, employing similar production technologies, were examined to assess the quality of the compost produced. Biochemical investigation highlighted changes in substrates through each step of the production cycle. Thermogravimetric analysis (TGA) provided useful information on fiber fraction content and extent of substrate breakdown. A comparison of productivity, chemical, and thermal data permitted assessment of the degree of bioconversion that had occurred in the decomposition from raw materials to finished substrate for each composter. One of the composters consistently produced substrate of inferior quality compared to the other two, indicating production inefficiencies during composting. Results demonstrated that allied to chemical analyses, TGA is a useful tool, providing valuable information on substrate quality and, in particular, for studying the bioconversion of lignocellulosic materials in mushroom compost.


Assuntos
Agaricus/química , Agaricus/metabolismo , Solo , Irlanda do Norte , Termogravimetria
14.
Endocrinology ; 147(1): 367-76, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16179407

RESUMO

Follicular thyroid carcinomas are associated with a chromosomal translocation that fuses the thyroid-specific transcription factor paired box gene 8 (PAX8) with the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma). This study investigated the transcriptional mechanisms by which PAX8-PPARgamma regulates follicular thyroid cells. In HeLa cells, rat follicular thyroid (FRTL-5) cells, or immortalized human thyroid cells, PAX8-PPARgamma stimulated transcription from PAX8-responsive thyroperoxidase and sodium-iodide symporter promoters in a manner at least comparable with wild-type PAX8. In contrast, PAX8-PPARgamma failed to stimulate transcription from the thyroglobulin promoter and blocked the synergistic stimulation of this promoter by wild-type PAX8 and thyroid transcription factor-1. Unexpectedly, PAX8-PPARgamma transcriptional function on a PPARgamma-responsive promoter was cell-type dependent; in HeLa cells, PAX8-PPARgamma dominantly inhibited expression of the PPARgamma-responsive promoter, whereas in FRTL-5 and immortalized human thyroid cells PAX8-PPARgamma stimulated this promoter. In gel shift analyses, PAX8-PPARgamma bound a PPARgamma-response element suggesting that its transcriptional function is mediated via direct DNA contact. A biological model of PAX8-PPARgamma function in follicular thyroid cells was generated via constitutive expression of the fusion protein in FRTL-5 cells. In this model, PAX8-PPARgamma expression was associated with enhanced growth as assessed by soft agar assays and thymidine uptake. Therefore, PAX8-PPARgamma disrupts normal transcriptional regulation by stimulating some genes and inhibiting others, the net effect of which may mediate follicular thyroid cell growth and loss of differentiation that ultimately leads to carcinogenesis.


Assuntos
PPAR gama/fisiologia , Fatores de Transcrição Box Pareados/fisiologia , Glândula Tireoide/citologia , Glândula Tireoide/fisiologia , Animais , Divisão Celular , Linhagem Celular , DNA/biossíntese , Células HeLa , Humanos , Rim , Fator de Transcrição PAX8 , PPAR gama/genética , Fatores de Transcrição Box Pareados/genética , Regiões Promotoras Genéticas , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Timidina/metabolismo , Transcrição Gênica , Transfecção
15.
J Gen Virol ; 86(Pt 1): 131-138, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15604440

RESUMO

The C-terminal tail of the gp41 transmembrane glycoprotein of the human immunodeficiency virus type 1 (HIV-1) virion is usually thought to be inside the virion, but it has been shown recently that part of the tail is exposed on the virion exterior. Here, using a panel of antibodies, it was demonstrated that the same part of the tail is exposed on the surface of HIV-1-infected C8166 lymphoblastoid cells and HeLa cells infected with a gp41-expressing vaccinia virus recombinant. Both types of infected cell failed to react with p17 matrix protein-specific IgGs until permeabilized with saponin, confirming the integrity of the plasma membrane. Cell-surface exposure of the gp41 tail was independently demonstrated by inhibition of HIV-1-mediated cell-cell fusion by one of the gp41 tail-specific antibodies. These data also implicate the exposed region of the gp41 C-terminal tail either directly or indirectly in the viral fusion process. Its surface exposure suggests that the gp41 C-terminal tail may be a candidate for immune intervention or chemotherapy of infection.


Assuntos
Proteína gp41 do Envelope de HIV/metabolismo , HIV-1/metabolismo , Fusão Celular , Linhagem Celular , Linhagem Celular Transformada , Parede Celular/metabolismo , Proteína gp41 do Envelope de HIV/química , Células HeLa , Humanos , Linfócitos T/metabolismo , Linfócitos T/virologia , Replicação Viral
16.
BMC Biol ; 2: 26, 2004 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-15613240

RESUMO

BACKGROUND: Tumour regression observed in many conditional mouse models following oncogene inactivation provides the impetus to develop, and a platform to preclinically evaluate, novel therapeutics to inactivate specific oncogenes. Inactivating single oncogenes, such as c-Myc, can reverse even advanced tumours. Intriguingly, transient c-Myc inactivation proved sufficient for sustained osteosarcoma regression; the resulting osteocyte differentiation potentially explaining loss of c-Myc's oncogenic properties. But would this apply to other tumours? RESULTS: We show that brief inactivation of c-Myc does not sustain tumour regression in two distinct tissue types; tumour cells in pancreatic islets and skin epidermis continue to avoid apoptosis after c-Myc reactivation, by virtue of Bcl-xL over-expression or a favourable microenvironment, respectively. Moreover, tumours progress despite reacquiring a differentiated phenotype and partial loss of vasculature during c-Myc inactivation. Interestingly, reactivating c-Myc in beta-cell tumours appears to result not only in further growth of the tumour, but also re-expansion of the accompanying angiogenesis and more pronounced beta-cell invasion (adenocarcinoma). CONCLUSIONS: Given that transient c-Myc inactivation could under some circumstances produce sustained tumour regression, the possible application of this potentially less toxic strategy in treating other tumours has been suggested. We show that brief inactivation of c-Myc fails to sustain tumour regression in two distinct models of tumourigenesis: pancreatic islets and skin epidermis. These findings challenge the potential for cancer therapies aimed at transient oncogene inactivation, at least under those circumstances where tumour cell differentiation and alteration of epigenetic context fail to reinstate apoptosis. Together, these results suggest that treatment schedules will need to be informed by knowledge of the molecular basis and environmental context of any given cancer.


Assuntos
Inativação Gênica , Genes myc , Insulinoma/genética , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogênicas c-myc/genética , Animais , Apoptose , Modelos Animais de Doenças , Progressão da Doença , Epiderme/efeitos dos fármacos , Epiderme/metabolismo , Epiderme/patologia , Feminino , Hidroxitestosteronas/farmacologia , Insulinoma/patologia , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Masculino , Camundongos , Camundongos Transgênicos , Neoplasias Pancreáticas/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo
17.
Brain Res Brain Res Rev ; 46(1): 44-70, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15297154

RESUMO

Sporadic Parkinson's disease (PD) is a common neurodegenerative disorder, characterized by the loss of midbrain dopamine neurons and Lewy body inclusions. It is thought to result from a complex interaction between multiple predisposing genes and environmental influences, although these interactions are still poorly understood. Several causative genes have been identified in different families. Mutations in two genes [alpha-synuclein and nuclear receptor-related 1 (Nurr1)] cause the same pathology, and a third locus on chromosome 2 also causes this pathology. Other familial PD mutations have identified genes involved in the ubiquitin-proteasome system [parkin and ubiquitin C-terminal hydroxylase L1 (UCHL1)], although such cases do not produce Lewy bodies. These studies highlight critical cellular proteins and mechanisms for dopamine neuron survival as disrupted in Parkinson's disease. Understanding the genetic variations impacting on dopamine neurons may illuminate other molecular mechanisms involved. Additional candidate genes involved in dopamine cell survival, dopamine synthesis, metabolism and function, energy supply, oxidative stress, and cellular detoxification have been indicated by transgenic animal models and/or screened in human populations with differing results. Genetic variation in genes known to produce different patterns and types of neurodegeneration that may impact on the function of dopamine neurons are also reviewed. These studies suggest that environment and genetic background are likely to have a significant influence on susceptibility to Parkinson's disease. The identification of multiple genes predisposing to Parkinson's disease will assist in determining the cellular pathway/s leading to the neurodegeneration observed in this disease.


Assuntos
Predisposição Genética para Doença , Doença por Corpos de Lewy/genética , Doença de Parkinson/genética , Animais , Dopamina/genética , Dopamina/metabolismo , Humanos , Doença por Corpos de Lewy/patologia , Mutação , Degeneração Neural/genética , Degeneração Neural/patologia , Neurônios/patologia , Doença de Parkinson/patologia
18.
J Gen Virol ; 84(Pt 3): 591-602, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12604810

RESUMO

The approximately 150 amino acid C-terminal tail of the gp41 transmembrane glycoprotein of human immunodeficiency virus type 1 (HIV-1) is generally thought to be located inside the virion. However, we show here that both monoclonal IgG and polyclonal epitope-purified IgG specific for the (746)ERDRD(750) epitope that lies within the C-terminal tail neutralized infectious virus. IgG was mapped to the C-terminal tail by its failure to neutralize tail-deleted virus, and by sequencing of antibody-escape mutants. The fact that antibody does not cross lipid membranes, and infectious virus is by definition intact, suggested that ERDRD was exposed on the surface of the virion. This was confirmed by reacting virus and IgG, separating virus and unbound IgG by centrifugation, and showing that virus was neutralized to essentially the same extent as virus that had been in constant contact with antibody. Epitope exposure on virions was independent of temperature and therefore constitutive. Monoclonal antibodies specific to epitopes PDRPEG and IEEE, upstream of ERDRD, also bound to virions, suggesting that they too were located externally. Protease digestion destroyed the ERDRD and PDRPEG epitopes, consistent with their proposed external location. Altogether these data are consistent with part of the C-terminal tail of gp41 being exposed on the outside of the virion. Possible models of the structure of the gp41 tail, taking these observations into account, are discussed.


Assuntos
Proteína gp41 do Envelope de HIV/imunologia , HIV-1/imunologia , Sequência de Aminoácidos , Anticorpos Antivirais/imunologia , Linhagem Celular , Endopeptidases , Mapeamento de Epitopos , Epitopos/análise , Epitopos/imunologia , Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/genética , HIV-1/metabolismo , Humanos , Imunoglobulina G/imunologia , Dados de Sequência Molecular , Testes de Neutralização
19.
J Clin Endocrinol Metab ; 88(1): 354-7, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12519876

RESUMO

Chromosomal translocations encoding fusion oncoproteins are common in hematological malignancies, sarcomas, and papillary thyroid carcinomas. A recent study of follicular thyroid carcinomas reported a novel chromosomal translocation, t(2;3)(q13;p25), that fused the thyroid-specific transcription factor PAX8 with a nuclear receptor, peroxisome proliferator-activated receptor gamma (PPAR gamma). Herein we report the detection of this putative oncoprotein in 6 of 17 (35%) follicular thyroid carcinomas as well as in 6 of 11 (55%) follicular thyroid adenomas. Concordant expression of protein was found in 91% of those tumors in which PAX8-PPAR gamma mRNA was detected by RT-PCR, whereas a further 20% of follicular tumors were positive for PPAR gamma immunohistochemistry alone. Our findings suggest that the PAX8-PPAR gamma fusion protein promotes differentiated follicular thyroid neoplasia, although it is not sufficient per se for carcinogenesis.


Assuntos
Adenocarcinoma Folicular/genética , Carcinoma Papilar/genética , Proteínas de Ligação a DNA/genética , Proteínas Nucleares , Oncogenes , Receptores Citoplasmáticos e Nucleares/genética , Proteínas Recombinantes de Fusão/genética , Neoplasias da Glândula Tireoide/genética , Transativadores/genética , Fatores de Transcrição/genética , Adenocarcinoma Folicular/metabolismo , Carcinoma Papilar/metabolismo , Expressão Gênica , Rearranjo Gênico , Humanos , Imuno-Histoquímica , Fator de Transcrição PAX8 , Fatores de Transcrição Box Pareados , RNA Mensageiro/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Neoplasias da Glândula Tireoide/metabolismo , Distribuição Tecidual , Fatores de Transcrição/metabolismo
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