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1.
Klin Mikrobiol Infekc Lek ; 29(1): 4-10, 2023 Mar.
Artigo em Tcheco | MEDLINE | ID: mdl-37586086

RESUMO

OBJECTIVES: The period of the COVID-19 pandemic had a significant impact on the healthcare system, including its effect on compliance with the established procedures of a rational antibiotic policy, especially in the context of nosocomial pneumonia, where it was very difficult to distinguish a possible bacterial superinfection from a severe inflammatory reaction caused by the SARS-CoV-2 virus. The aim of the present study was to analyze the antimicrobial resistance of bacterial pathogens isolated from the lower respiratory tract and their clonality in intensive care patients in 2022 and to compare it with the previous COVID-19 period. MATERIAL AND METHODS: Bacterial strains isolated from the lower respiratory tract (LRT) of patients hospitalized at the Department of Anaesthesiology, Resuscitation and Intensive Care, Olomouc University Hospital (DARIC) over a three-year period (January 1, 2020 - December 31, 2022) were included in the study. The susceptibility to antibiotics was determined by the standard microdilution method according to the EUCAST criteria, and selected isolates were compared using pulsed-field gel electrophoresis (PFGE). RESULTS: The resistance of the most common bacterial pathogens isolated from the LRT of patients hospitalized at DARIC did not change significantly during the COVID-19 (2020-2021) and post-COVID-19 (2022) periods, with the exception of Serratia marcescens and Enterococcus faecium species. These two showed an increase in the number of strains during the COVID-19 pandemic, as well as a significant increase in the proportion of resistant strains. In the case of Serratia marcescens, there was a subsequent decrease in the number of isolates and their resistance in 2022. For Enterococcus faecium, the total number of isolates also decreased significantly, but the frequency of vancomycin-resistant isolates (VRE) continued to increase. During the COVID-19 pandemic, increased VRE detection can be linked to proven clonal spread, but significant clonality was no longer confirmed in 2022. Comparison of similarity by PFGE in other bacterial species also did not reveal significant horizontal transmission between patients in the post-COVID-19 period, as most isolates (85%) showed a unique restriction profile. CONCLUSIONS: The results indicate that the frequency and antimicrobial resistance of the majority of the most common bacterial pathogens from the LRT of patients hospitalized at DARIC in the post-pandemic period remain comparable to the time before and during the COVID-19 pandemic outbreak. An exception is Enterococcus faecium, which showed an increase in vancomycin resistance in both the COVID-19 and the post-COVID-19 periods.


Assuntos
COVID-19 , Enterococcus faecium , Infecções por Bactérias Gram-Positivas , Humanos , Pandemias , COVID-19/epidemiologia , SARS-CoV-2 , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Enterococcus , Cuidados Críticos , Sistema Respiratório , Infecções por Bactérias Gram-Positivas/microbiologia , Testes de Sensibilidade Microbiana
2.
Klin Mikrobiol Infekc Lek ; 28(2): 36-41, 2022 Jun.
Artigo em Tcheco | MEDLINE | ID: mdl-36546467

RESUMO

OBJECTIVES: The COVID-19 pandemic has had a major impact on the healthcare system, which has been forced to manage large numbers of patients, including those with respiratory insufficiency and in need of oxygen therapy. Due to concerns about bacterial co-infection, antibiotic therapy was administered to many patients. The aim of the present study was to compare antimicrobial resistance in intensive care patients in the pre-pandemic and pandemic periods. MATERIAL AND METHODS: Patients hospitalized at the Department of Anesthesiology, Resuscitation and Intensive Care Medicine of the University Hospital Olomouc in the pre-COVID-19 period (2018-2019) and during the pandemic (2020-2021) were enrolled in the study. Clinical samples from the lower respiratory tract were routinely collected twice a week, with one strain of a given species first isolated from each patient being included in the study. RESULTS: While several bacterial species (Escherichia coli, Proteus mirabilis and Haemophilus influenzae) were found to occur less frequently, an increased occurrence was documented for Enterococcus faecium, Serratia marcescens and Klebsiella variicola. Overall, however, it can be concluded that there was no major change in the frequency of bacterial pathogens isolated from the lower respiratory tract during the COVID-19 period. Similarly, with only a few exceptions, antimicrobial resistance did not change significantly. More significant increases in resistance to piperacillin/tazobactam, cefotaxime, ciprofloxacin and gentamicin have been demonstrated for Serratia marcescens. However, a decrease in the resistance of Pseudomonas aeruginosa and Burkholderia cepacia complex to meropenem was also observed. CONCLUSIONS: There was no significant change in the frequency of bacterial pathogens and their resistance to antibiotics during the COVID-19 pandemic. However, there was an increase or decrease in the percentage of some species and in their resistance.


Assuntos
Infecções Bacterianas , COVID-19 , Humanos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Pandemias , Farmacorresistência Bacteriana , Bactérias , Infecções Bacterianas/tratamento farmacológico , Testes de Sensibilidade Microbiana
3.
Exp Cell Res ; 386(1): 111709, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31704058

RESUMO

Regulation of phosphatidylinositol phosphates plays a crucial role in signal transduction, membrane trafficking or autophagy. Members of the myotubularin family of lipid phosphatases contribute to phosphoinositide metabolism by counteracting the activity of phosphoinositide kinases. The mechanisms determining their subcellular localization and targeting to specific membrane compartments are still poorly understood. We show here that the inactive phosphatase MTMR9 localizes to the intermediate compartment and to the Golgi apparatus and is able to recruit its active phosphatase partners MTMR6 and MTMR8 to these locations. Furthermore, MTMR8 and MTMR9 co-localize with the small GTPase RAB1A and regulate its localization. Loss of MTMR9 expression compromises the integrity of the Golgi apparatus and results in altered distribution of RAB1A and actin nucleation-promoting factor WHAMM. Loss or overexpression of MTMR9 leads to decreased rate of protein secretion. We demonstrate that secretion of physiologically relevant cargo exemplified by the WNT3A protein is affected after perturbation of MTMR9 levels.


Assuntos
Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Proteínas Tirosina Fosfatases não Receptoras/metabolismo , Exocitose , Células HEK293 , Células HeLa , Humanos , Transporte Proteico , Proteínas Tirosina Fosfatases não Receptoras/genética , Via de Sinalização Wnt , Proteína Wnt3A/metabolismo , Proteínas rab1 de Ligação ao GTP/metabolismo
4.
Klin Mikrobiol Infekc Lek ; 27(4): 135-141, 2021 Dec.
Artigo em Tcheco | MEDLINE | ID: mdl-35220573

RESUMO

Treatment of COVID-19 patients and their extreme numbers represented an unprecedented challenge for the intensive care system in healthcare facilities throughout the Czech Republic, a country particularly affected by the new coronavirus SARS-CoV-2 pandemic. A steep increase in the need for intensive care placed an excess burden on bed and staff capacity. For a severe and critical course of COVID-19, bilateral pneumonia with acute hypoxemic respiratory failure is pathognomonic. In the intensive care setting, COVID-19 therapy is primarily symptomatic, supporting failing respiratory function to gain time needed to restore it and to repair the lungs. The aggressiveness and comprehensiveness of respiratory support depend on the severity of failure, ranging from simple oxygen therapy, to non-invasive support and mechanical ventilation, to extracorporeal support. By contrast, specific COVID-19 therapy is directly targeted against SARS-CoV-2 or modulates the organism's response to the virus. Primary, virus-induced lung injury may be secondarily complicated by coinfection or superinfection, most commonly bacterial, increasing the severity and lethality of the disease. Therefore, anti-infective therapy is crucial for the prognosis and outlook of intensive care COVID-19 patients. Among nosocomial infections complicating COVID-19, ventilator-associated pneumonia (developing in mechanically ventilated patients) is particularly important and challenging, and so are issues related to bacterial resistance and rational antibiotic therapy.


Assuntos
COVID-19 , Insuficiência Respiratória , COVID-19/complicações , Cuidados Críticos , Humanos , Pandemias , Insuficiência Respiratória/etiologia , Insuficiência Respiratória/terapia , SARS-CoV-2
5.
Vnitr Lek ; 67(8): 448-454, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35459363

RESUMO

The COVID-19 pandemic may increase the current threat of antimicrobial resistance and exacerbate another, rather silent, pandemic posed by the increasing frequency of multidrug-resistant bacterial pathogens and the associated potential for loss of effective antibiotics. Antibiotic treatment has often been used in patients hospitalized for COVID-19 due to concerns about possible bacterial co-infection, as confirmed by previous experience with viral respiratory infections such as H1N1 influenza, SARS and MERS. Concerns or unknowns related to the COVID-19 pandemic have also affected physicians behavior, including the use of antibiotics. However, the high rate of antibiotic use in patients, especially those with mild to moderate COVID-19 disease, is inconsistent with the actual incidence of bacterial co-infections and/or secondary respiratory infections. Thus, it is clear that a careful assessment of the role of antibiotic treatment in patients hospitalized for COVID-19 is required. According to the current WHO recommendation, the application of antibiotics is especially suitable for patients with severe/critical degree of respiratory insufficiency requiring intensive oxygen therapy, artificial lung ventilation or support by extracorporeal membrane oxygenation.


Assuntos
Infecções Bacterianas , COVID-19 , Vírus da Influenza A Subtipo H1N1 , Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/epidemiologia , Humanos , Pandemias , SARS-CoV-2
6.
Klin Mikrobiol Infekc Lek ; 24(1): 4-9, 2018 03.
Artigo em Tcheco | MEDLINE | ID: mdl-30016532

RESUMO

Hospital-acquired pneumonia (HAP) is an infection of the lung parenchyma. It is the second most frequent nosocomial infection and the leading cause of death from infection in critically ill patients. Hospital-acquired and, particularly, ventilator-associated pneumonia prolong the hospital stay and increase treatment costs. The clinical signs of pneumonia are rather non-specific, with limited possibilities to distinguish the lung condition from other nosological entities. The yield, effectiveness and cost of new rapid diagnostic procedures as well as early biochemical markers specific for pneumonia have not been sufficiently verified and clinical translation of technological innovations is slow. In bedside clinical practice, the diagnosis continues to be based on clinical examination together with imaging methods, most frequently X-ray. The spectrum of etiologic agents changes, with an increase in the prevalence of multidrug-resistant (MDR) bacterial pathogens. Initial antibiotic therapy, particularly in critically ill ventilated patients, needs to include broad-spectrum agents due to the risk of the presence of MDR bacteria. The likelihood of successful treatment may be increased by regular updates of recommendations for adequate initial antibiotherapy with regard to the epidemiological situation and knowledge of bacterial resistance to antimicrobials in a particular hospital and region. As part of the current valid guidelines, recommendation were newly translated; however, their level of evidence is often very low and the strength of recommendation is mostly weak or moderate. Their benefit to everyday practice is questionable. The article points to changes brought about by the recent European guidelines published in fall 2017 and summarizes current issues concerning HAP pathogens in intensive care units in the Czech Republic.


Assuntos
Antibacterianos/uso terapêutico , Infecção Hospitalar/microbiologia , Pneumonia Bacteriana/microbiologia , Pneumonia Bacteriana/prevenção & controle , Pneumonia Associada à Ventilação Mecânica/microbiologia , Pneumonia Associada à Ventilação Mecânica/prevenção & controle , República Tcheca/epidemiologia , Humanos , Assistência ao Paciente , Pneumonia Bacteriana/tratamento farmacológico , Pneumonia Bacteriana/epidemiologia , Pneumonia Associada à Ventilação Mecânica/tratamento farmacológico , Pneumonia Associada à Ventilação Mecânica/epidemiologia , Prevalência , Fatores de Risco
7.
Klin Mikrobiol Infekc Lek ; 21(1): 4-9, 2015 Mar.
Artigo em Tcheco | MEDLINE | ID: mdl-26098487

RESUMO

BACKGROUND: The aim of the study was to compare the validity of bronchial secretion sampling and bronchoscopy-assisted protected specimen brushing (PSB) in patients with hospital-acquired pneumonia (HAP). MATERIALS AND METHODS: In patients with HAP, bronchial secretion samples (aspiration of lower airway secretions from an orotracheal tube with a suctioning catheter) and PSB (bronchoscopy-assisted sampling from the most affected area of the lung, verified by CT scan) were taken at the same time. Both samples were processed by semiquantitative routine microbiological techniques. Identification of microorganisms was performed by standard microbiological techniques using the MALDI-TOF automated system. For similarity or identity determination of bacterial isolates from bronchial secretion sampling and PSB, pulsed-field gel electrophoresis was used. RESULTS: Thirty patients were enrolled into the study. Thirty pairs of bronchial secretion samples and PSB samples were obtained and processed. The samples were positive in 23 patients (77 %) and 15 patients (50 %), respectively. In 15 cases, the same pathogen was determined in both samples, and in all those cases, the isolates were genetically identical. CONCLUSION: The results of the study show that bronchial secretion samples analysis enabled identification of all pathogens that were identified by PSB. Given the high sensitivity of the bronchial secretion aspiration technique and genetic identity of isolates in both samples, bronchial secretion sampling may be recommended for determining HAP etiological agents as the samples are much easier to obtain from patients.


Assuntos
Bactérias/isolamento & purificação , Infecção Hospitalar/diagnóstico , Infecção Hospitalar/microbiologia , Pneumonia Bacteriana/diagnóstico , Pneumonia Bacteriana/microbiologia , Adulto , Idoso , Bactérias/classificação , Broncoscopia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Manejo de Espécimes
8.
Antibiotics (Basel) ; 13(2)2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38391578

RESUMO

The impact of bacterial pneumonia on patients with COVID-19 infection remains unclear. This prospective observational monocentric cohort study aims to determine the incidence of bacterial community- and hospital-acquired pneumonia (CAP and HAP) and its effect on mortality in critically ill COVID-19 patients admitted to the intensive care unit (ICU) at University Hospital Olomouc between 1 November 2020 and 31 December 2022. The secondary objectives of this study include identifying the bacterial etiology of CAP and HAP and exploring the capabilities of diagnostic tools, with a focus on inflammatory biomarkers. Data were collected from the electronic information hospital system, encompassing biomarkers, microbiological findings, and daily visit records, and subsequently evaluated by ICU physicians and clinical microbiologists. Out of 171 patients suffering from critical COVID-19, 46 (27%) had CAP, while 78 (46%) developed HAP. Critically ill COVID-19 patients who experienced bacterial CAP and HAP exhibited higher mortality compared to COVID-19 patients without any bacterial infection, with rates of 38% and 56% versus 11%, respectively. In CAP, the most frequent causative agents were chlamydophila and mycoplasma; Enterobacterales, which were multidrug-resistant in 71% of cases; Gram-negative non-fermenting rods; and Staphylococcus aureus. Notably, no strains of Streptococcus pneumoniae were detected, and only a single strain each of Haemophilus influenzae and Moraxella catarrhalis was isolated. The most frequent etiologic agents causing HAP were Enterobacterales and Gram-negative non-fermenting rods. Based on the presented results, commonly used biochemical markers demonstrated poor predictive and diagnostic accuracy. To confirm the diagnosis of bacterial CAP in our patient cohort, it was necessary to assess the initial values of inflammatory markers (particularly procalcitonin), consider clinical signs indicative of bacterial infection, and/or rely on positive microbiological findings. For HAP diagnostics, it was appropriate to conduct regular detailed clinical examinations (with a focus on evaluating respiratory functions) and closely monitor the dynamics of inflammatory markers (preferably Interleukin-6).

9.
Antibiotics (Basel) ; 11(6)2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35740188

RESUMO

This observational retrospective study aimed to analyze whether/how the spectrum of bacterial pathogens and their resistance to antibiotics changed during the worst part of the COVID-19 pandemic (1 November 2020 to 30 April 2021) among intensive care patients in University Hospital Olomouc, Czech Republic, as compared with the pre-pandemic period (1 November 2018 to 30 April 2019). A total of 789 clinically important bacterial isolates from 189 patients were cultured during the pre-COVID-19 period. The most frequent etiologic agents causing nosocomial infections were strains of Klebsiella pneumoniae (17%), Pseudomonas aeruginosa (11%), Escherichia coli (10%), coagulase-negative staphylococci (9%), Burkholderia multivorans (8%), Enterococcus faecium (6%), Enterococcus faecalis (5%), Proteus mirabilis (5%) and Staphylococcus aureus (5%). Over the comparable COVID-19 period, a total of 1500 bacterial isolates from 372 SARS-CoV-2-positive patients were assessed. While the percentage of etiological agents causing nosocomial infections increased in Enterococcus faecium (from 6% to 19%, p < 0.0001), Klebsiella variicola (from 1% to 6%, p = 0.0004) and Serratia marcescens (from 1% to 8%, p < 0.0001), there were significant decreases in Escherichia coli (from 10% to 3%, p < 0.0001), Proteus mirabilis (from 5% to 2%, p = 0.004) and Staphylococcus aureus (from 5% to 2%, p = 0.004). The study demonstrated that the changes in bacterial resistance to antibiotics are ambiguous. An increase in the frequency of ESBL-positive strains of some species (Serratia marcescens and Enterobacter cloacae) was confirmed; on the other hand, resistance decreased (Escherichia coli, Acinetobacter baumannii) or the proportion of resistant strains remained unchanged over both periods (Klebsiella pneumoniae, Enterococcus faecium). Changes in pathogen distribution and resistance were caused partly due to antibiotic selection pressure (cefotaxime consumption increased significantly in the COVID-19 period), but mainly due to clonal spread of identical bacterial isolates from patient to patient, which was confirmed by the pulse field gel electrophoresis methodology. In addition to the above shown results, the importance of infection prevention and control in healthcare facilities is discussed, not only for dealing with SARS-CoV-2 but also for limiting the spread of bacteria.

10.
Nucleic Acids Res ; 37(9): 3007-20, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19304756

RESUMO

A major outcome of the canonical Wnt/beta-catenin-signalling pathway is the transcriptional activation of a specific set of target genes. A typical feature of the transcriptional response induced by Wnt signalling is the involvement of Tcf/Lef factors that function in the nucleus as the principal mediators of signalling. Vertebrate Tcf/Lef proteins perform two well-characterized functions: in association with beta-catenin they activate gene expression, and in the absence of Wnt ligands they bind TLE/Groucho proteins to act as transcriptional repressors. Although the general characteristics of Tcf/Lef factors are well understood, the mechanisms that control their specific roles in various cellular backgrounds are much less defined. In this report we reveal that the evolutionary conserved Dazap2 protein functions as a TCF-4 interacting partner. We demonstrate that a short region proximal to the TCF-4 HMG box mediates the interaction and that all Tcf/Lef family members associate with Dazap2. Interestingly, knockdown of Dazap2 not only reduced the activity of Wnt signalling as measured by Tcf/beta-catenin reporters but additionally altered the expression of Wnt-signalling target genes. Finally, chromatin immunoprecipitation studies indicate that Dazap2 modulates the affinity of TCF-4 for its DNA-recognition motif.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a RNA/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Gênica , Proteínas Wnt/metabolismo , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Sítios de Ligação , Linhagem Celular , Proteínas de Ligação a DNA/química , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Regiões Promotoras Genéticas , Proteínas de Ligação a RNA/antagonistas & inibidores , Proteínas de Ligação a RNA/genética , Fator de Transcrição 4 , Fatores de Transcrição/química , beta Catenina/metabolismo
11.
Life (Basel) ; 11(11)2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34833003

RESUMO

Broad-spectrum antibiotics administered to patients with severe COVID-19 pneumonia pose a risk of infection caused by Clostridioides difficile. This risk is reduced mainly by strict hygiene measures and early de-escalation of antibiotic therapy. Recently, oral vancomycin prophylaxis (OVP) has also been discussed. This retrospective study aimed to assess the prevalence of C. difficile in critical COVID-19 patients staying in an intensive care unit of a tertiary hospital department of anesthesiology, resuscitation, and intensive care from November 2020 to May 2021 and the rates of vancomycin-resistant enterococci (VRE) after the introduction of OVP and to compare the data with those from controls in the pre-pandemic period (November 2018 to May 2019). During the COVID-19 pandemic, there was a significant increase in toxigenic C. difficile rates to 12.4% of patients, as compared with 1.6% in controls. The peak rates were noted in February 2021 (25% of patients), immediately followed by initiation of OVP, changes to hygiene precautions, and more rapid de-escalation of antibiotic therapy. Subsequently, toxigenic C. difficile detection rates started to fall. There was a nonsignificant increase in VRE detected in non-gastrointestinal tract samples to 8.9% in the COVID-19 group, as compared to 5.3% in the control group. Molecular analysis confirmed mainly clonal spread of VRE.

12.
Biochim Biophys Acta ; 1793(10): 1579-87, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19654028

RESUMO

Death receptor 6 (DR6/TNFRSF21) is a death domain-containing receptor of the TNFR superfamily with an apparent regulatory function in hematopoietic and neuronal cells. In this study we document that DR6 is an extensively posttranslationally modified transmembrane protein and that N- and O-glycosylations of amino acids in its extracellular part are mainly responsible for its approximately 40 kDa mobility shift in SDS polyacrylamide gels. Site-directed mutagenesis confirmed that all six extracellular asparagines are N-glycosylated and that the Ser/Thr/Pro cluster in the "stalk" domain juxtaposed to the cysteine-rich domains (CRDs) is a major site for the likely mucine-type of O-glycosylation. Deletion of the entire linker region between CRDs and the transmembrane domain, spanning over 130 amino acids, severely compromises the plasma membrane localization of DR6 and leads to its intracellular retention. Biosynthetic labeling with radiolabeled palmitate and side-directed mutagenesis also revealed that the membrane-proximal Cys368 in the intracellular part of DR6 is, similarly as cysteines in Fas/CD95 or DR4 ICPs, S-palmitoylated. However, palmitoylation of Cys368 is apparently not required for DR6 targeting into Brij-98 insoluble lipid rafts. In contrast, we show that N-glycosylation of the extracellular part might participate in directing DR6 into these membrane microdomains.


Assuntos
Receptores do Fator de Necrose Tumoral/química , Receptores do Fator de Necrose Tumoral/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Glicosilação , Células HL-60 , Células HeLa , Humanos , Células Jurkat , Lipoilação , Masculino , Microdomínios da Membrana/metabolismo , Peso Molecular , Mutagênese Sítio-Dirigida , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/fisiologia , Processamento de Proteína Pós-Traducional , Estrutura Terciária de Proteína , Receptores do Fator de Necrose Tumoral/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Deleção de Sequência
13.
Apoptosis ; 13(4): 573-87, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18347988

RESUMO

Wnt signaling enhances cell proliferation and the maintenance of hematopoietic cells. In contrast, cytotoxic ligand Apo2L/TRAIL induces the apoptosis of various transformed cells. We observed that co-culture of human pre-B leukemia cells KM3 and REH with Wnt1- or Wnt3a-producing rat embryonic fibroblasts efficiently suppressed Apo2L/TRAIL-induced apoptosis of the lymphoid cells. This suppression occurs at the early stages of the Apo2L/TRAIL apoptotic cascade and, interestingly, the activation of the Wnt pathway alone in human leukemia cells is not sufficient for their full anti-apoptotic protection. We hypothesize that a stimulus emanating specifically from Wnt1- or Wnt3a-expressing rat fibroblasts is responsible for the observed resistance to Apo2L/TRAIL. This anti-apoptotic signaling was significantly hampered by the inhibition of the MEK1/ERK1/2 or NFkappaB pathways in KM3 and REH cells. Our results imply that paracrine Wnt-related signals could be important for the survival of pre-B cell-derived malignancies.


Assuntos
Apoptose/fisiologia , Ligante Indutor de Apoptose Relacionado a TNF/antagonistas & inibidores , Proteínas Wnt/biossíntese , Proteína Wnt1/biossíntese , Animais , Proteínas Reguladoras de Apoptose/fisiologia , Linhagem Celular Tumoral , Técnicas de Cocultura , Cicloeximida/farmacologia , Dactinomicina/farmacologia , Humanos , Leucemia-Linfoma Linfoblástico de Células Precursoras B , Ratos , Transdução de Sinais/fisiologia , Proteína Wnt3 , Proteína Wnt3A , beta Catenina/fisiologia
14.
Mol Cancer Ther ; 6(9): 2591-9, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17876056

RESUMO

Cytokines such as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce apoptosis in colon cancer cells through engagement of death receptors. Nevertheless, evading apoptosis induced by anticancer drugs characterizes many types of cancers. This results in the need for combination therapy. In this study, we have investigated whether the flavonoid quercetin could sensitize human colon adenocarcinoma cell lines to TRAIL-induced apoptosis. We report that quercetin enhanced TRAIL-induced apoptosis by causing the redistribution of DR4 and DR5 into lipid rafts. Nystatin, a cholesterol-sequestering agent, prevented quercetin-induced clustering of death receptors and sensitization to TRAIL-induced apoptosis in colon adenocarcinoma cells. In addition, our experiments show that quercetin, in combination with TRAIL, triggered the mitochondrial-dependent death pathway, as shown by Bid cleavage and the release of cytochrome c to the cytosol. Together, our findings propose that quercetin, through its ability to redistribute death receptors at the cell surface, facilitates death-inducing signaling complex formation and activation of caspases in response to death receptor stimulation. Based on these results, this study provides a challenging approach to enhance the efficiency of TRAIL-based therapies.


Assuntos
Apoptose/efeitos dos fármacos , Neoplasias do Colo/tratamento farmacológico , Microdomínios da Membrana/efeitos dos fármacos , Quercetina/farmacologia , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Receptores do Fator de Necrose Tumoral/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/metabolismo , Caspases/efeitos dos fármacos , Caspases/metabolismo , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Citocromos c/metabolismo , Citosol/efeitos dos fármacos , Citosol/metabolismo , Proteínas Adaptadoras de Sinalização de Receptores de Domínio de Morte/metabolismo , Citometria de Fluxo , Imunofluorescência , Humanos , Immunoblotting , Imunoprecipitação , Microdomínios da Membrana/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Células Tumorais Cultivadas/efeitos dos fármacos
15.
Artigo em Inglês | MEDLINE | ID: mdl-27003315

RESUMO

BACKGROUND: Hospital-acquired pneumonia (HAP) is associated with high mortality. In Central Europe, there is a dearth of information on the prevalence and treatment of HAP. This project was aimed at collecting multicenter epidemiological data on patients with HAP in the Czech Republic and comparing them with supraregional data. METHODS: This prospective, multicenter, observational study processed data from a database supported by a Czech Ministry of Health grant project. Included were all consecutive patients aged 18 and over who were admitted to participating intensive care units (ICUs) between 1 May 2013 and 31 December 2014 and met the inclusion criterion of having HAP. The primary endpoint was to analyze the relationships between 30-day mortality (during the stay in or after discharge from ICUs) and the microbiological etiological agent and adequacy of initial empirical antibiotic therapy in HAP patients. RESULTS: The group dataset contained data on 330 enrolled patients. The final validated dataset involved 214 patients, 168 males (78.5%) and 46 females (21.5%), from whom 278 valid lower airway samples were obtained. The mean patient age was 59.9 years. The mean APACHE II score at admission was 21. Community-acquired pneumonia was identified in 13 patients and HAP in 201 patients, of whom 26 (12.1%) had early-onset and 175 (81.8%) had late-onset HAP. Twenty-two bacterial species were identified as etiologic agents but only six of them exceeded a frequency of detection of 5% (Klebsiella pneumoniae 20.4%, Pseudomonas aeruginosa 20.0%, Escherichia coli 10.8%, Enterobacter spp. 8.1%, Staphylococcus aureus 6.2% and Burkholderia cepacia complex 5.8%). Patients infected with Staphylococcus aureus had significantly higher rates of early-onset HAP than those with other etiologic agents. The overall 30-day mortality rate for HAP was 29.9%, with 19.2% mortality for early-onset HAP and 31.4% mortality for late-onset HAP. Patients with late-onset HAP receiving adequate initial empirical antibiotic therapy had statistically significantly lower 30-day mortality than those receiving inadequate initial antibiotic therapy (23.8% vs 42.9%). Patients with ventilator-associated pneumonia (VAP) had significantly higher mortality than those who developed HAP with no association with mechanical ventilation (34.6% vs 12.7%). Patients having VAP treated with adequate initial antibiotic therapy had lower 30-day mortality than those receiving inadequate therapy (27.2% vs 44.8%). CONCLUSIONS: The present study was the first to collect multicenter data on the epidemiology of HAP in the Central European Region, with respect to the incidence of etiologic agents causing HAP. It was concerned with relationships between 30-day patient mortality and the type of HAP, etiologic agent and adequacy of initial empirical antibiotic therapy.


Assuntos
Infecção Hospitalar/epidemiologia , Pneumonia Bacteriana/epidemiologia , Antibacterianos/uso terapêutico , República Tcheca/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pneumonia Associada à Ventilação Mecânica/epidemiologia , Prevalência , Estudos Prospectivos
16.
Cell Signal ; 23(5): 837-48, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21244856

RESUMO

The Wnt family of proteins is a group of extracellular signalling molecules that regulate cell-fate decisions in developing and adult tissues. It is presumed that all 19 mammalian Wnt family members contain two types of post-translational modification: the covalent attachment of fatty acids at two distinct positions, and the N-glycosylation of multiple asparagines. We examined how these modifications contribute to the secretion, extracellular movement and signalling activity of mouse Wnt1 and Wnt3a ligands. We revealed that O-linked acylation of serine is required for the subsequent S-palmitoylation of cysteine. As such, mutant proteins that lack the crucial serine residue are not lipidated. Interestingly, although double-acylation of Wnt1 was indispensable for signalling in mammalian cells, in Xenopus embryos the S-palmitoyl-deficient form retained the signalling activity. In the case of Wnt3a, the functional duality of the attached acyls was less prominent, since the ligand lacking S-linked palmitate was still capable of signalling in various cellular contexts. Finally, we show that the signalling competency of both Wnt1 and Wnt3a is related to their ability to associate with the extracellular matrix.


Assuntos
Cisteína/metabolismo , Serina/metabolismo , Proteínas Wnt/metabolismo , Proteína Wnt1/metabolismo , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Linhagem Celular , Desenvolvimento Embrionário , Humanos , Lipoilação , Camundongos , Dados de Sequência Molecular , Mutação , Ratos , Proteínas Wnt/genética , Proteína Wnt1/genética , Proteína Wnt3 , Proteína Wnt3A , Xenopus/embriologia , Xenopus/metabolismo , Proteínas de Xenopus
17.
Artigo em Inglês | MEDLINE | ID: mdl-20445713

RESUMO

AIM: To determine the incidence of postoperative nausea and vomiting (PONV), identify risk factors, assess treatment and its effectiveness. DESIGN: A prospective, observational, questionnaire- and interview-based study. SETTING: Standard and intensive care units of the following university hospital departments: abdominal, thoracic and vascular surgery; gynecology; plastic and esthetic surgery; urology; and traumatology. MATERIAL AND METHODS: Adult patients scheduled for elective surgery who gave informed consent were enrolled. A questionnaire-based study was performed on the first postoperative day. The collected data relevant to PONV were statistically analyzed. CONCLUSION: The incidence of PONV was significantly lower than generally presumed and was related to the patient gender, type of surgery and overall health status. PONV was more frequent in obese patients and when drugs antagonizing opioids or muscle relaxants were used. Early administration of antiemetic agents led to considerably less discomfort.


Assuntos
Náusea e Vômito Pós-Operatórios , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Hospitais Universitários , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Náusea e Vômito Pós-Operatórios/epidemiologia , Náusea e Vômito Pós-Operatórios/etiologia , Náusea e Vômito Pós-Operatórios/fisiopatologia , Náusea e Vômito Pós-Operatórios/terapia , Fatores de Risco , Adulto Jovem
18.
EMBO J ; 25(11): 2326-37, 2006 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-16724116

RESUMO

The hypermethylated in cancer 1 (HIC1) gene is epigenetically inactivated in cancer, and in addition, the haploinsufficiency of HIC1 is linked to the development of human Miller-Dieker syndrome. HIC1 encodes a zinc-finger transcription factor that acts as a transcriptional repressor. Additionally, the HIC1 protein oligomerizes via the N-terminal BTB/POZ domain and forms discrete nuclear structures known as HIC1 bodies. Here, we provide evidence that HIC1 antagonizes the TCF/beta-catenin-mediated transcription in Wnt-stimulated cells. This appears to be due to the ability of HIC1 to associate with TCF-4 and to recruit TCF-4 and beta-catenin to the HIC1 bodies. As a result of the recruitment, both proteins are prevented from association with the TCF-binding elements of the Wnt-responsive genes. These data indicate that the intracellular amounts of HIC1 protein can modulate the level of the transcriptional stimulation of the genes regulated by canonical Wnt/beta-catenin signaling.


Assuntos
Núcleo Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Transdução de Sinais/fisiologia , Fatores de Transcrição TCF/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Animais , Proteína Axina , Meios de Cultivo Condicionados , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica , Humanos , Fatores de Transcrição Kruppel-Like , Camundongos , Regiões Promotoras Genéticas , Ligação Proteica , Interferência de RNA , Fatores de Transcrição TCF/genética , Proteína 2 Semelhante ao Fator 7 de Transcrição , Fatores de Transcrição/genética , Transcrição Gênica , Proteínas Wnt/genética , beta Catenina/genética
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