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1.
Anesth Analg ; 131(1): 74-85, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32243296

RESUMO

The World Health Organization (WHO) has declared coronavirus disease 2019 (COVID-19), the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a pandemic. Global health care now faces unprecedented challenges with widespread and rapid human-to-human transmission of SARS-CoV-2 and high morbidity and mortality with COVID-19 worldwide. Across the world, medical care is hampered by a critical shortage of not only hand sanitizers, personal protective equipment, ventilators, and hospital beds, but also impediments to the blood supply. Blood donation centers in many areas around the globe have mostly closed. Donors, practicing social distancing, some either with illness or undergoing self-quarantine, are quickly diminishing. Drastic public health initiatives have focused on containment and "flattening the curve" while invaluable resources are being depleted. In some countries, the point has been reached at which the demand for such resources, including donor blood, outstrips the supply. Questions as to the safety of blood persist. Although it does not appear very likely that the virus can be transmitted through allogeneic blood transfusion, this still remains to be fully determined. As options dwindle, we must enact regional and national shortage plans worldwide and more vitally disseminate the knowledge of and immediately implement patient blood management (PBM). PBM is an evidence-based bundle of care to optimize medical and surgical patient outcomes by clinically managing and preserving a patient's own blood. This multinational and diverse group of authors issue this "Call to Action" underscoring "The Essential Role of Patient Blood Management in the Management of Pandemics" and urging all stakeholders and providers to implement the practical and commonsense principles of PBM and its multiprofessional and multimodality approaches.


Assuntos
Bancos de Sangue/organização & administração , Transfusão de Sangue , Infecções por Coronavirus , Pandemias , Pneumonia Viral , Doadores de Sangue , COVID-19 , Infecções por Coronavirus/terapia , Infecções por Coronavirus/transmissão , Medicina Baseada em Evidências , Humanos , Pneumonia Viral/terapia , Pneumonia Viral/transmissão
2.
Mov Disord ; 32(10): 1478-1482, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28643901

RESUMO

BACKGROUND: Compromised iron status is important in restless legs syndrome pathophysiology. We compared the efficacy and tolerability of ferric carboxymaltose (single intravenous dose) versus placebo for restless legs syndrome treatment in iron-deficient nonanemic patients. METHODS: Patients with moderate to severe restless legs syndrome and serum ferritin < 75 µg/L (or serum ferritin 75-300 µg/L and transferrin saturation < 20%) were randomized to ferric carboxymaltose (1000 mg iron) or placebo. Mean change difference between ferric carboxymaltose and placebo in International Restless Legs Syndrome Severity Scale score from baseline to week 4 was the primary end point; week 12 was a secondary end point. RESULTS: Ferric carboxymaltose treatment (n = 59) led to nonsignificant improvement over placebo (n = 51) in International Restless Legs Syndrome Severity Scale score at week 4 (difference [95% confidence interval], -2.5 [-5.93 to 1.02], P = 0.163), reaching significance by week 12 (-4.66 [-8.59 to -0.73], P = 0.021). CONCLUSIONS: In patients who responded to treatment, ferric carboxymaltose may require more time to stabilize restless legs syndrome than previously assumed. © 2017 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.


Assuntos
Compostos Férricos/uso terapêutico , Hematínicos/uso terapêutico , Distúrbios do Metabolismo do Ferro/tratamento farmacológico , Maltose/análogos & derivados , Síndrome das Pernas Inquietas/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Feminino , Ferritinas/sangue , Humanos , Distúrbios do Metabolismo do Ferro/sangue , Masculino , Maltose/uso terapêutico , Pessoa de Meia-Idade , Estudos Prospectivos , Síndrome das Pernas Inquietas/sangue , Método Simples-Cego , Fatores de Tempo , Resultado do Tratamento
3.
J Perinat Med ; 45(4): 443-453, 2017 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-27278921

RESUMO

OBJECTIVE: To compare the efficacy and safety of intravenous ferric carboxymaltose (FCM) with first-line oral ferrous sulfate (FS) in pregnant women with iron deficiency anemia (IDA). MATERIALS AND METHODS: Pregnant women (n=252; gestational weeks 16-33) with IDA were randomized 1:1 to FCM (1000-1500 mg iron) or FS (200 mg iron/day) for 12 weeks. The primary objective was to compare efficacy; secondary objectives included safety and quality of life. RESULTS: Hemoglobin (Hb) levels improved at comparable rates across both treatments; however, significantly more women achieved anemia correction with FCM vs. FS [Hb ≥11.0 g/dL; 84% vs. 70%; odds ratio (OR): 2.06, 95% confidence interval (CI): 1.07, 3.97; P=0.031] and within a shorter time frame (median 3.4 vs. 4.3 weeks). FCM treatment significantly improved vitality (P=0.025) and social functioning (P=0.049) prior to delivery. Treatment-related adverse events were experienced by 14 (FCM; 11%) and 19 (FS; 15%) women, with markedly higher rates of gastrointestinal disorders reported with FS (16 women) than with FCM (3 women). Newborn characteristics were similar across treatments. CONCLUSIONS: During late-stage pregnancy, FCM may be a more appropriate option than first-line oral iron for rapid and effective anemia correction, with additional benefits for vitality and social functioning.


Assuntos
Anemia Ferropriva/tratamento farmacológico , Compostos Férricos/administração & dosagem , Compostos Ferrosos/administração & dosagem , Maltose/análogos & derivados , Complicações Hematológicas na Gravidez/tratamento farmacológico , Administração Intravenosa , Administração Oral , Adulto , Anemia Ferropriva/sangue , Feminino , Compostos Férricos/efeitos adversos , Compostos Ferrosos/efeitos adversos , Humanos , Recém-Nascido , Maltose/administração & dosagem , Maltose/efeitos adversos , Gravidez , Qualidade de Vida , Resultado do Tratamento
4.
Eur J Anaesthesiol ; 32(3): 160-7, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25564780

RESUMO

BACKGROUND: Patient blood management (PBM) can prevent preoperative anaemia, but little is known about practice in Europe. OBJECTIVE: To assess the pre and postoperative prevalence and perioperative management of anaemia in patients undergoing elective orthopaedic surgery in Europe. DESIGN: An observational study; data were collected from patient records via electronic case report forms. SETTING: Seventeen centres in six European countries. Centres were stratified according to whether they had a PBM programme or not. PATIENTS: One thousand five hundred and thirty-four patients undergoing major elective hip, knee or spine surgery [49.9% hip, 37.2% knee, 13.0% spine; age 64.0 years (range 18 to 80), 61.3% female]. MAIN OUTCOME MEASURES: Prevalence of preoperative (primary endpoint) and postoperative anaemia [haemoglobin (Hb) <13 g dl (male), Hb <12 g dl (female)], perioperative anaemia management, time to first blood transfusion and number of transfused units. Data are shown as mean (SD) or median (interquartile range). RESULTS: Anaemia prevalence increased from 14.1% preoperatively to 85.8% postoperatively. Mean Hb decrease was 1.9 (1.5) and 3.0 (1.3) g dl in preoperatively anaemic and nonanaemic patients, respectively (P < 0.001). In PBM (n = 7) vs. non-PBM centres, preoperative anaemia was less frequent (8.0 vs. 18.5%; P < 0.001) and iron status was assessed more frequently (ferritin 11.0 vs. 2.6%, transferrin saturation 11.0 vs. 0.1%; P < 0.001). Perioperative anaemia correction (mainly transfusion) was given to 34.3%. Intraoperatively, 14.8% of preoperatively anaemic and 2.8% of nonanaemic patients received transfusions [units per patient: 2.4 (1.5) and 2.2 (1.4), median time to first intraoperative transfusion: 130 (88, 158) vs. 179 (135, 256) min; P < 0.001]. Postoperative complications were more frequent in preoperatively anaemic vs. nonanaemic patients (36.9 vs. 22.2%; P = 0.009). CONCLUSION: Most patients who underwent elective orthopaedic surgery had normal preoperative Hb levels but became anaemic after the procedure. Those who were anaemic prior to surgery had an increased intraoperative transfusion risk and postoperative complication rate. PBM measures such as iron status assessment and strategies to avoid transfusion are still underused in Europe.


Assuntos
Anemia/epidemiologia , Anemia/terapia , Transfusão de Eritrócitos , Hematínicos/uso terapêutico , Procedimentos Ortopédicos/efeitos adversos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anemia/sangue , Anemia/diagnóstico , Biomarcadores/sangue , Procedimentos Cirúrgicos Eletivos , Registros Eletrônicos de Saúde , Transfusão de Eritrócitos/efeitos adversos , Europa (Continente)/epidemiologia , Feminino , Ferritinas/sangue , Hematínicos/efeitos adversos , Hemoglobinas/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Cuidados Pré-Operatórios , Prevalência , Fatores de Risco , Fatores de Tempo , Transferrina/metabolismo , Resultado do Tratamento , Adulto Jovem
5.
Front Med ; 18(1): 98-108, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37897561

RESUMO

Iron deficiency (ID) and ID anemia (IDA) pose significant public health concerns in China. Although iron sucrose (IS) treatment is well-established in the country, ferric carboxymaltose (FCM) offers the advantage of higher doses and fewer infusions. This open label, randomized, controlled, non-inferiority trial was conducted at multiple sites in China to compare the outcomes of FCM (maximum of 2 doses, 500 or 1000 mg iron) and IS (up to 11 infusions, 200 mg iron) treatments in subjects with IDA. The primary endpoint was the achievement of hemoglobin (Hb) response (an increase of ⩾2 g/dL from baseline) within 8 weeks, whereas secondary endpoints included changes in Hb, transferrin saturation, and serum ferritin levels. Among the 371 randomized subjects, a similar percentage of subjects treated with FCM and IS achieved Hb-response (FCM 99.4%, IS 98.3%), thereby confirming the non-inferiority of FCM compared with IS (difference 1.12 (-2.15, 4.71; 95% confidence interval (CI))). Furthermore, a significantly higher proportion of FCM-treated subjects achieved early Hb-response at Week 2 (FCM 85.2%, IS 73.2%; difference 12.1 (3.31, 20.65; 95% CI)). Additionally, the increase in TSAT and serum ferritin levels from baseline was significantly greater at all time points for FCM-treated subjects. The safety profiles of FCM and IS were comparable, with the exception of transient hypophosphatemia and pyrexia, which are consistent with FCM's known safety profile. In conclusion, FCM proves to be an efficacious treatment for IDA, providing faster Hb-response and correction of ID with fewer administrations than IS.

6.
J Cell Biol ; 168(3): 477-88, 2005 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-15668298

RESUMO

Simian Virus 40 (SV40) has been shown to enter host cells by caveolar endocytosis followed by transport via caveosomes to the endoplasmic reticulum (ER). Using a caveolin-1 (cav-1)-deficient cell line (human hepatoma 7) and embryonic fibroblasts from a cav-1 knockout mouse, we found that in the absence of caveolae, but also in wild-type embryonic fibroblasts, the virus exploits an alternative, cav-1-independent pathway. Internalization was rapid (t1/2 = 20 min) and cholesterol and tyrosine kinase dependent but independent of clathrin, dynamin II, and ARF6. The viruses were internalized in small, tight-fitting vesicles and transported to membrane-bounded, pH-neutral organelles similar to caveosomes but devoid of cav-1 and -2. The viruses were next transferred by microtubule-dependent vesicular transport to the ER, a step that was required for infectivity. Our results revealed the existence of a virus-activated endocytic pathway from the plasma membrane to the ER that involves neither clathrin nor caveolae and that can be activated also in the presence of cav-1.


Assuntos
Cavéolas/fisiologia , Caveolinas/fisiologia , Clatrina/fisiologia , Endocitose/fisiologia , Vírus 40 dos Símios/metabolismo , Fator 6 de Ribosilação do ADP , Fatores de Ribosilação do ADP/genética , Fatores de Ribosilação do ADP/fisiologia , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/fisiologia , Proteínas Adaptadoras de Transdução de Sinal , Animais , Antígenos Virais de Tumores/metabolismo , Brefeldina A/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Proteínas de Ligação ao Cálcio/genética , Caveolina 1 , Caveolina 2 , Caveolinas/análise , Caveolinas/genética , Linhagem Celular , Linhagem Celular Tumoral , Colesterol/deficiência , Colesterol/fisiologia , Detergentes/química , Dinamina II/genética , Dinamina II/fisiologia , Embrião de Mamíferos/citologia , Endocitose/efeitos dos fármacos , Retículo Endoplasmático Liso/química , Retículo Endoplasmático Liso/fisiologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/ultraestrutura , Fibroblastos/virologia , Expressão Gênica , Genisteína/farmacologia , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Microdomínios da Membrana/química , Microdomínios da Membrana/fisiologia , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Microtúbulos/efeitos dos fármacos , Microtúbulos/fisiologia , Nocodazol/farmacologia , Fosfoproteínas/genética , Vírus da Floresta de Semliki/fisiologia , Tiazóis/farmacologia , Tiazolidinas , Transferrina/metabolismo , Vesículas Transportadoras/fisiologia , Vesículas Transportadoras/ultraestrutura
7.
J Cell Biol ; 170(5): 769-79, 2005 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-16129785

RESUMO

Using total internal reflection fluorescence microscopy (TIR-FM), fluorescence recovery after photobleaching (FRAP), and other light microscopy techniques, we analyzed the dynamics, the activation, and the assembly of caveolae labeled with fluorescently tagged caveolin-1 (Cav1). We found that when activated by simian virus 40 (SV40), a non-enveloped DNA virus that uses caveolae for cell entry, the fraction of mobile caveolae was dramatically enhanced both in the plasma membrane (PM) and in the caveosome, an intracellular organelle that functions as an intermediate station in caveolar endocytosis. Activation also resulted in increased microtubule (MT)-dependent, long-range movement of caveolar vesicles. We generated heterokaryons that contained GFP- and RFP-tagged caveolae by fusing cells expressing Cav1-GFP and -RFP, respectively, and showed that even when activated, individual caveolar domains underwent little exchange of Cav1. Only when the cells were subjected to transient cholesterol depletion, did the caveolae domain exchange Cav1. Thus, in contrast to clathrin-, or other types of coated transport vesicles, caveolae constitute stable, cholesterol-dependent membrane domains that can serve as fixed containers through vesicle traffic. Finally, we identified the Golgi complex as the site where newly assembled caveolar domains appeared first.


Assuntos
Cavéolas/metabolismo , Caveolinas/metabolismo , Vesículas Transportadoras/metabolismo , Caveolina 1 , Caveolinas/genética , Membrana Celular/química , Membrana Celular/metabolismo , Colesterol/metabolismo , Recuperação de Fluorescência Após Fotodegradação , Corantes Fluorescentes/metabolismo , Complexo de Golgi/metabolismo , Células HeLa , Humanos , Microscopia de Fluorescência/métodos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Vírus 40 dos Símios/metabolismo
8.
Int J Gynaecol Obstet ; 128(3): 196-200, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25627706

RESUMO

OBJECTIVE: To examine the prevalence and impact of heavy menstrual bleeding (HMB) among women in Europe, and their experience of HMB assessment and management. METHODS: An internet-based survey was conducted among women (aged 18-57 years) in five European countries between January and February 2012. The prevalence of HMB among the general population was determined in a short survey, and women who had been diagnosed with HMB were then asked to complete an extended survey about their diagnosis and symptoms. RESULTS: Overall, 4506 women responded, of whom 1225 (27.2%) had experienced two or more predefined HMB symptoms within the previous year. Of these women, 564 (46.0%) had never consulted a physician. Among 330 women who completed the detailed survey, 208 (63.0%) had ever been diagnosed with iron deficiency or iron-deficiency anemia. Symptoms associated with iron deficiency were used to help confirm a diagnosis in 83 (39.9%) women. Only 152 (46.1%) of the 330 patients with confirmed HMB had received prescription medication for iron deficiency. CONCLUSION: Many women affected by HMB do not seek medical help, and few of those who do consult physicians report that they have received appropriate treatment. HMB continues to be underdiagnosed and poorly treated.


Assuntos
Anemia Ferropriva/epidemiologia , Deficiências de Ferro , Menorragia/epidemiologia , Adolescente , Adulto , Coleta de Dados , Europa (Continente)/epidemiologia , Feminino , Humanos , Internet , Pessoa de Meia-Idade , Prevalência , Adulto Jovem
9.
Cancer Gene Ther ; 9(7): 597-605, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12082460

RESUMO

We have constructed and tested five recombinant adenoviruses (Ads) that express a variety of immunomodulators, including CD40 ligand (CD40L), a potent costimulator of several components of the immune system. We demonstrate that CD40L expressed from Ad in K1735 mouse melanoma cells leads to a strong reduction in tumorigenicity and to efficient protective immunity in a vaccination setting. Subsequently, using a therapeutic approach, we found that local, intratumoral coinjection of CD40L- and IL-2-expressing Ads was superior to any other agents tested and resulted in an at least 1.9-fold increase in mean survival time, in contrast to systemic application of recombinant CD40L or GM-CSF proteins, which had no significant effects. When using vaccination as a therapeutic approach, the combinations of CD40L plus IL-2 or GM-CSF plus IL-2 from Ad gave rise to an extended (2.8-fold) increase in mean survival time. A detailed analysis of immune cells present within regressing tumors indicated that mainly CD4(+) and CD8(+) T cells, and to a lesser extent dendritic cells, infiltrated the tumor mass, but not NK cells, macrophages, or granulocytes. These results propose that a combination of CD40L plus IL-2 has an improved efficacy over the use of single agents when applied for direct in situ therapy or vaccination therapy.


Assuntos
Adenoviridae/genética , Ligante de CD40/genética , Terapia Genética/métodos , Imunoterapia/métodos , Melanoma/terapia , Animais , Intervalo Livre de Doença , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Granulócitos/metabolismo , Imuno-Histoquímica , Interleucina-2/metabolismo , Células Matadoras Naturais/metabolismo , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C3H , Transplante de Neoplasias , Fatores de Tempo , Células Tumorais Cultivadas , Vacinas de DNA
10.
PLoS One ; 9(4): e94217, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24751822

RESUMO

BACKGROUND: Unexplained fatigue is often left untreated or treated with antidepressants. This randomized, placebo-controlled, single-blinded study evaluated the efficacy and tolerability of single-dose intravenous ferric carboxymaltose (FCM) in iron-deficient, premenopausal women with symptomatic, unexplained fatigue. METHODS: Fatigued women (Piper Fatigue Scale [PFS] score ≥5) with iron deficiency (ferritin <50 µg/L and transferrin saturation <20%, or ferritin <15 µg/L) and normal or borderline hemoglobin (≥115 g/L) were enrolled in 21 sites in Austria, Germany, Sweden and Switzerland, blinded to the study drug and randomized (computer-generated randomization sequence) to a single FCM (1000 mg iron) or saline (placebo) infusion. Primary endpoint was the proportion of patients with reduced fatigue (≥1 point decrease in PFS score from baseline to Day 56). RESULTS: The full analysis included 290 women (FCM 144, placebo 146). Fatigue was reduced in 65.3% (FCM) and 52.7% (placebo) of patients (OR 1.68, 95%CI 1.05-2.70; p = 0.03). A 50% reduction of PFS score was achieved in 33.3% FCM- vs. 16.4% placebo-treated patients (p<0.001). At Day 56, all FCM-treated patients had hemoglobin levels ≥120 g/L (vs. 87% at baseline); with placebo, the proportion decreased from 86% to 81%. Mental quality-of-life (SF-12) and the cognitive function scores improved better with FCM. 'Power of attention' improved better in FCM-treated patients with ferritin <15 µg/L. Treatment-emergent adverse events (placebo 114, FCM 209; most frequently headache, nasopharyngitis, pyrexia and nausea) were mainly mild or moderate. CONCLUSION: A single infusion of FCM improved fatigue, mental quality-of-life, cognitive function and erythropoiesis in iron-deficient women with normal or borderline hemoglobin. Although more side effects were reported compared to placebo, FCM can be an effective alternative in patients who cannot tolerate or use oral iron, the common treatment of iron deficiency. Overall, the results support the hypothesis that iron deficiency can affect women's health, and a normal iron status should be maintained independent of hemoglobin levels. TRIAL REGISTRATION: ClinicalTrials.gov NCT01110356.


Assuntos
Fadiga/tratamento farmacológico , Compostos Férricos/uso terapêutico , Deficiências de Ferro , Maltose/análogos & derivados , Adulto , Cognição , Relação Dose-Resposta a Droga , Determinação de Ponto Final , Índices de Eritrócitos , Fadiga/sangue , Fadiga/fisiopatologia , Feminino , Compostos Férricos/administração & dosagem , Compostos Férricos/efeitos adversos , Hemoglobinas/metabolismo , Humanos , Análise de Intenção de Tratamento , Maltose/administração & dosagem , Maltose/efeitos adversos , Maltose/uso terapêutico , Placebos , Qualidade de Vida , Transferrina/metabolismo
11.
Biophys J ; 89(3): 1482-92, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15951382

RESUMO

The determination of diffusion coefficients from fluorescence recovery data is often complicated by geometric constraints imposed by the complex shapes of intracellular compartments. To address this issue, diffusion of proteins in the lumen of the endoplasmic reticulum (ER) is studied using cell biological and computational methods. Fluorescence recovery after photobleaching (FRAP) experiments are performed in tissue culture cells expressing GFP-KDEL, a soluble, fluorescent protein, in the ER lumen. The three-dimensional (3D) shape of the ER is determined by confocal microscopy and computationally reconstructed. Within these ER geometries diffusion of solutes is simulated using the method of particle strength exchange. The simulations are compared to experimental FRAP curves of GFP-KDEL in the same ER region. Comparisons of simulations in the 3D ER shapes to simulations in open 3D space show that the constraints imposed by the spatial confinement result in two- to fourfold underestimation of the molecular diffusion constant in the ER if the geometry is not taken into account. Using the same molecular diffusion constant in different simulations, the observed speed of fluorescence recovery varies by a factor of 2.5, depending on the particular ER geometry and the location of the bleached area. Organelle shape considerably influences diffusive transport and must be taken into account when relating experimental photobleaching data to molecular diffusion coefficients. This novel methodology combines experimental FRAP curves with high accuracy computer simulations of diffusion in the same ER geometry to determine the molecular diffusion constant of the solute in the particular ER lumen.


Assuntos
Biofísica/métodos , Espectrometria de Fluorescência/métodos , Animais , Membrana Celular/metabolismo , Chlorocebus aethiops , Simulação por Computador , Técnicas de Cultura , Citoplasma/metabolismo , DNA/química , Difusão , Retículo Endoplasmático/metabolismo , Fluorescência , Proteínas de Fluorescência Verde/química , Substâncias Macromoleculares/química , Microscopia Confocal , Modelos Estatísticos , Conformação de Ácido Nucleico , Fotodegradação , Conformação Proteica , Proteínas/química , Fatores de Tempo , Células Vero
12.
Traffic ; 3(11): 833-49, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12383349

RESUMO

Quality control in the secretory pathway limits forward transport of newly synthesized cargo proteins to those that have acquired their fully folded conformation. To determine which organelles participate in this conformation-dependent sorting process, we analyzed the trafficking of the temperature-sensitive, thermo-reversible folding mutant of vesicular stomatitis virus glycoprotein (tsO45 G protein) in VERO cells. Using temperature blocks, the G protein could be localized to the ER (39.5 degrees C), to the vesiculo-tubular clusters (VTCs, 15 degrees C), and to the trans-Golgi network (TGN, 20 degrees C). To localize the G protein specifically to ER exit sites, we incubated cells at 10 degrees C. The exit sites contained Sec13p, a COPII component, and were devoid of calnexin and other ER chaperones. We found that if the G protein in the exit sites was misfolded by a temperature shift from 10 degrees C to 39.5 degrees C, it failed to enter the VTCs. Instead, it was returned to the reticular ER where it associated with calnexin. However, if the G protein was in the VTCs or beyond, its folding status no longer affected further transport. The observations indicate that quality control took place in the ER and in the ER transitional elements, but not in the VTCs or the Golgi complex. The results provide a way to discriminate biochemically between exit sites and VTCs, two related structures that are difficult to distinguish from each other.


Assuntos
Retículo Endoplasmático/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas do Envelope Viral/metabolismo , Animais , Transporte Biológico/efeitos dos fármacos , Brefeldina A/farmacologia , Chlorocebus aethiops , Retículo Endoplasmático/efeitos dos fármacos , Complexo de Golgi/metabolismo , Proteínas de Fluorescência Verde , Proteínas Luminescentes/metabolismo , Glicoproteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mutação , Complexo de Proteínas Formadoras de Poros Nucleares , Conformação Proteica , Dobramento de Proteína , Inibidores da Síntese de Proteínas/farmacologia , Proteínas Recombinantes/metabolismo , Proteínas de Saccharomyces cerevisiae , Temperatura , Células Vero , Vírus da Estomatite Vesicular Indiana/química , Vírus da Estomatite Vesicular Indiana/metabolismo , Proteínas do Envelope Viral/genética
13.
J Virol ; 77(7): 4370-82, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12634393

RESUMO

It is believed that flavivirus assembly occurs by intracellular budding of the nucleocapsid into the lumen of the endoplasmic reticulum (ER). Recombinant expression of tick-borne encephalitis (TBE) virus envelope proteins prM and E in mammalian cells leads to their incorporation into enveloped recombinant subviral particles (RSPs), which have been used as a model system for studying assembly and entry processes and are also promising vaccine candidates. In this study, we analyzed the formation and secretion of TBE virus RSPs and of a membrane anchor-free E homodimer in mammalian cells. Immunofluorescence microscopy showed that E was accumulated in the lumen of the ER. RSPs were observed by electron microscopy in the rough and smooth ER and in downstream compartments of the secretory pathway. About 75% of the particles appeared to be of the size expected for RSPs (about 30 nm in diameter), but a number of larger particles and tubular structures were also observed in these compartments. Secretion of membrane anchor-free E dimers was detected 30 min after synthesis of prM and E, and secretion of RSPs was detected 1 h after synthesis of prM and E. We also found that the presence of the single N-linked oligosaccharide side chain on the E protein and its trimming by glucosidases was necessary for secretion of RSPs and truncated E dimers. Our results suggest that incorporation of prM and E into RSPs occurs at the ER membrane without other viral elements being required, followed by rapid transport along the compartments of the secretory pathway and secretion. Moreover, the carbohydrate side chain of E is involved in at least one assembly or transport step.


Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/crescimento & desenvolvimento , Vírus da Encefalite Transmitidos por Carrapatos/ultraestrutura , Animais , Células COS , Vírus da Encefalite Transmitidos por Carrapatos/genética , Corpos de Inclusão Viral/ultraestrutura , Cinética , Microscopia Eletrônica , Polissacarídeos/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transfecção , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Montagem de Vírus
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