RESUMO
The marine cyanobacterium Prochlorococcus is a main contributor to global photosynthesis, whilst being limited by iron availability. Cyanobacterial genomes generally encode two different types of FutA iron-binding proteins: periplasmic FutA2 ABC transporter subunits bind Fe(III), while cytosolic FutA1 binds Fe(II). Owing to their small size and their economized genome Prochlorococcus ecotypes typically possess a single futA gene. How the encoded FutA protein might bind different Fe oxidation states was previously unknown. Here, we use structural biology techniques at room temperature to probe the dynamic behavior of FutA. Neutron diffraction confirmed four negatively charged tyrosinates, that together with a neutral water molecule coordinate iron in trigonal bipyramidal geometry. Positioning of the positively charged Arg103 side chain in the second coordination shell yields an overall charge-neutral Fe(III) binding state in structures determined by neutron diffraction and serial femtosecond crystallography. Conventional rotation X-ray crystallography using a home source revealed X-ray-induced photoreduction of the iron center with observation of the Fe(II) binding state; here, an additional positioning of the Arg203 side chain in the second coordination shell maintained an overall charge neutral Fe(II) binding site. Dose series using serial synchrotron crystallography and an XFEL X-ray pump-probe approach capture the transition between Fe(III) and Fe(II) states, revealing how Arg203 operates as a switch to accommodate the different iron oxidation states. This switching ability of the Prochlorococcus FutA protein may reflect ecological adaptation by genome streamlining and loss of specialized FutA proteins.
Assuntos
Compostos Férricos , Prochlorococcus , Compostos Férricos/química , Proteínas de Ligação ao Ferro/metabolismo , Prochlorococcus/metabolismo , Ferro/metabolismo , Oxirredução , Transferrina/metabolismo , Água/química , Compostos Ferrosos/química , Cristalografia por Raios XRESUMO
BACKGROUND: Thrombosis is linked to neutrophil release of neutrophil extracellular traps (NETs). NETs are proposed as a mechanism of resistance to thrombolysis. This study intends to analyze the composition of thrombi retrieved after mechanical thrombectomy, estimate the age and organization of thrombi, and evaluate associations with the use of thrombolysis, antiplatelets, and heparin. METHODS: This retrospective observational study involved 72 samples (44 from cerebral and 28 coronary arteries), which were stained with hematoxylin and eosin, anti-NE (neutrophil elastase) antibody, and anti-histone H2B (histone H2B) antibody, representing different components in NET formation, all detectable during the later stages of NETosis, for histochemical and digital quantification of NET content. The histological and morphological evaluations of the specimens were correlated, through univariate and mediation analyses, with clinical information and therapy administered before intervention. RESULTS: The results demonstrated that the composition of cerebral and coronary thrombi differs, and there were significantly more lytic cerebral thrombi than coronary thrombi (66% versus 14%; P=0.005). There was a considerably higher expression of NETs in the cerebral thrombi as testified by the higher expression of H2B (P=0.031). Thrombolysis was remarkably associated with higher NE positivity (average marginal effect, 6.461 [95% CI, 0.7901-12.13]; P=0.02555), regardless of the origin of thrombi. There was no notable association between the administration of antiaggregant therapy/heparin and H2B/NE amount when adjusted for the thrombus location. Importantly, the age of the thrombus was the only independent predictor of NET content without any mediation of the thrombolytic treatment (P=0.014). CONCLUSIONS: The age of the thrombus is the driving force for NET content, which correlates with impaired clinical outcomes. The therapy that is currently administered does not modify NET content. This study supports the need to investigate new pharmacological approaches added to thrombolysis to prevent NET formation or enhance their disruption, such as recombinant human DNase I (deoxyribonuclease I).
Assuntos
Armadilhas Extracelulares , Trombose , Humanos , Armadilhas Extracelulares/metabolismo , Neutrófilos/metabolismo , Trombose/tratamento farmacológico , Trombose/metabolismo , Histonas/metabolismo , Terapia Trombolítica , HeparinaRESUMO
AIM: Treatment with sacubitril/valsartan (S/V) significantly improves cardiovascular morbidity, mortality, quality of life and prolongs the survival of chronic heart failure patients with reduced ejection fraction. The aim of the study was to evaluate changes in ejection fraction, NT-proBNP and glomerular filtration after 12 months of sacubitril/valsartan treatment. METHODS: 30 patients (28 men) with chronic heart failure with reduced ejection fraction, functional classes NYHA II-III, EF LK < 40%, NT-proBNP (> 450 ng/l), with glomerular filtration > 0.5 ml/s/1.73 m2, with a potassium < 5.4 mmol/l were classified in the study. S/V treatment was started at systolic blood pressure > 100 mmHg. Ejection fraction, glomerular filtration rate and NT-proBNP values were compared before treatment and after 12 months of S/V treatment. The number of hospitalizations and deaths was also monitored. RESULTS: During 12 months of S/V treatment there was a significant improvement in left ventricular ejection fraction (median initial 26.3%, after treatment 36.3%, difference 7.5%, p.
Assuntos
Insuficiência Cardíaca , Qualidade de Vida , Aminobutiratos , Antagonistas de Receptores de Angiotensina , Biomarcadores , Compostos de Bifenilo , Combinação de Medicamentos , Insuficiência Cardíaca/tratamento farmacológico , Humanos , Masculino , Volume Sistólico , Tetrazóis , Valsartana , Função Ventricular EsquerdaRESUMO
BACKGROUND: Bioresorbable scaffold (BRS) Absorb™ clinical use has been stopped due to higher rate of device thrombosis. Scaffold struts persist longer than 2 years in the vessel wall. Second generation devices are being developed. This study evaluates long-term invasive imaging in STEMI patients. METHODS: PRAGUE-19 study is an academic study enrolling consecutive STEMI patients with intention to implant Absorb™ BRS. A total of 83 STEMI patients between December 2012 and March 2014 fulfilled entry criteria. Coronary angiography and optical coherence tomography at 5 year follow-up was performed in 25 patients. RESULTS: Primary combined clinical endpoint (death, myocardial infarction or target vessel revascularization) occurred in 12.6% during the five-year follow-up with overall mortality 6.3%. Definite scaffold thrombosis occurred in 2 patients in the early phase after BRS implantation. Quantitative coronary angiography after 5 years demonstrated low late lumen loss of 0.11 ± 0.35 mm with binary restenosis rate of 0%. Optical coherence tomography demonstrated complete resorption of scaffold struts and mean lumen diameter of 3.25 ± 0.30 and 3.22 ± 0.49 (P = 0.73) at baseline and after 5 years, respectively. Three patients developed small coronary artery aneurysm in the treated segment. CONCLUSION: Invasive imaging results 5 years after BRS implantation in STEMI showed complete resorption of scaffold struts and stable lumen vessel diameter. Trial registration ISRCTN43696201 (retrospectivelly registred, June 7th, 2019). https://www.isrctn.com/ISRCTN43696201.
Assuntos
Stents Farmacológicos , Intervenção Coronária Percutânea , Infarto do Miocárdio com Supradesnível do Segmento ST , Implantes Absorvíveis , Angiografia Coronária , Humanos , Desenho de Prótese , Infarto do Miocárdio com Supradesnível do Segmento ST/diagnóstico por imagem , Infarto do Miocárdio com Supradesnível do Segmento ST/cirurgia , Resultado do TratamentoRESUMO
Incomplete stent apposition and uncovered struts are associated with a higher risk of stent thrombosis. No data exist on the process of neointimal coverage and late apposition status of the bioresorbable vascular scaffold (BVS) when implanted in the highly thrombogenic setting of ST-segment elevation acute myocardial infarction (STEMI). The aim of this study was to assess the serial changes in strut apposition and early neointimal coverage of the BVS using optical coherence tomography (OCT) in selected patients enrolled in the PRAGUE-19 study. Intracoronary OCT was performed in 50 patients at the end of primary percutaneous coronary intervention for acute STEMI. Repeated OCT of the implanted BVS was performed in 10 patients. Scaffold area, scaffold mean diameter and incomplete strut apposition (ISA) were compared between baseline and control OCT. Furthermore, strut neointimal coverage was assessed during the control OCT. Mean scaffold area and diameter did not change between the baseline and control OCT (8.59 vs. 9.06 mm(2); p = 0.129 and 3.31 vs. 3.37 mm; p = 0.202, respectively). Differences were observed in ISA between the baseline and control OCT (0.63 vs. 1.47 %; p < 0.05). We observed 83.1 % covered struts in eight patients in whom the control OCT was performed 4-6 weeks after BVS implantation, and 100 % covered struts in two patients 6 months after BVS implantation. Persistent strut apposition and early neointimal coverage were observed after biodegradable vascular scaffold implantation in patients with acute ST-segment elevation myocardial infarction.
Assuntos
Implantes Absorvíveis , Fármacos Cardiovasculares/administração & dosagem , Materiais Revestidos Biocompatíveis , Vasos Coronários/efeitos dos fármacos , Everolimo/administração & dosagem , Neointima , Intervenção Coronária Percutânea/instrumentação , Infarto do Miocárdio com Supradesnível do Segmento ST/terapia , Idoso , Fármacos Cardiovasculares/efeitos adversos , Angiografia Coronária , Vasos Coronários/diagnóstico por imagem , República Tcheca , Everolimo/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Intervenção Coronária Percutânea/efeitos adversos , Estudos Prospectivos , Desenho de Prótese , Infarto do Miocárdio com Supradesnível do Segmento ST/diagnóstico por imagem , Fatores de Tempo , Tomografia de Coerência Óptica , Resultado do TratamentoRESUMO
AIMS: Bioresorbable vascular scaffolds (BVSs) have been studied in chronic coronary artery disease, but not in acute ST-segment elevation myocardial infarction (STEMI). This prospective multicentre study analysed the feasibility and safety of BVS implantation during primary percutaneous coronary intervention (p-PCI) in STEMI. METHODS AND RESULTS: Bioresorbable vascular scaffold implantation became the default strategy for all consecutive STEMI patients between 15 December 2012 and 30 August 2013. A total of 142 patients underwent p-PCI; 41 of them (28.9%) fulfilled the inclusion/exclusion criteria for BVS implantation. The BVS device success was 98%, thrombolysis in myocardial infarction 3 flow was restored in 95% of patients, and acute scaffold recoil was 9.7%. An optical coherence tomography (OCT) substudy (21 patients) demonstrated excellent procedural results with only a 1.1% rate of scaffold strut malapposition. Edge dissections were present in a 38% of patients, but were small and clinically silent. Reference vessel diameter measured by quantitative coronary angiography was significantly lower than that measured by OCT by 0.29 (±0.56) mm, P = 0.028. Clinical outcomes were compared between BVS group and Control group; the latter was formed by patients who had implanted metallic stent and were in Killip Class I or II. Combined clinical endpoint was defined as death, myocardial infarction, or target vessel revascularization. Event-free survival was the same in both groups; 95% for BVS and 93% for Control group, P = 0.674. CONCLUSION: Bioresorbable vascular scaffold implantation in acute STEMI is feasible and safe. The procedural results evaluated by angiography and OCT are excellent. The early clinical results are encouraging.
Assuntos
Stents Farmacológicos , Infarto do Miocárdio/terapia , Alicerces Teciduais , Implantes Absorvíveis , Idoso , Angiografia Coronária , Estudos de Viabilidade , Feminino , Humanos , Masculino , Inibidores da Agregação Plaquetária/administração & dosagem , Estudos Prospectivos , Tomografia de Coerência Óptica , Resultado do TratamentoRESUMO
Inflammatory bowel disease, encompassing Crohn's disease and ulcerative colitis, is a persistent immune-mediated inflammatory gastrointestinal disease. This study investigates the role of growth differentiation factor 15 in severe IBD cases, aiming to identify a reliable parameter to assess disease severity and monitor activity. We analyzed plasma samples from 100 patients undergoing biologic therapy for severe IBD and 50 control subjects. Our analysis included evaluations of GDF-15 levels, inflammatory markers, and clinical features. We employed statistical methods such as the Mann-Whitney U test, ANOVA, and Spearman's correlation for an in-depth analysis. Our results demonstrated consistently higher GDF-15 levels in patients with both Crohn's disease and ulcerative colitis compared to the control group, irrespective of the biologic treatment received. The correlation analysis indicated significant relationships between GDF-15 levels, patient age, fibrinogen, and IL-6 levels. This study positions GDF-15 as a promising biomarker for severe IBD, with notable correlations with age and inflammatory markers. These findings underscore GDF-15's potential in enhancing disease monitoring and management strategies in an IBD context and encourage further research to clarify GDF-15's role in the IBD pathophysiology.
RESUMO
BACKGROUND: Atherosclerosis is a major cause of ischemic stroke, and early detection of advanced atherosclerosis in the carotid artery is important for reducing morbidity and mortality. What is even more important is not only detection of atherosclerosis but early determination whether the patients are at high risk of an event with adverse effects as the size of the plaque does not necessarily reflect its potential to trigger such events. AIM: We studied whether plasma lipidomics profile can be used as a diagnostic tool for stratification of stable or unstable plaques without the need of removing the carotid plaque. METHODS: This study used liquid chromatography high-resolution tandem mass spectrometry lipidomics to characterize lipid profiles in patients' plasma and found that patients with significant and complicated (vulnerable) atherosclerotic plaque had distinct lipid profiles compared to those with insignificant plaques. RESULTS: The lipid classes that were most predictive of vulnerable plaque were lysophosphoethanolamines, fatty acyl esters of hydroxy fatty acids, free fatty acids, plasmalogens, and triacylglycerols. Most of these compounds were found decreased in plasma of patients with unstable plaques which enabled sufficient performance of a statistical model used for patient stratification. CONCLUSIONS: Plasma lipidomes measured by liquid chromatography-mass spectrometry show differences in patients with stable and unstable carotid plaques, therefore these compounds could potentially be used as biomarkers for unstable plaque in future clinical diagnosis.
Assuntos
Biomarcadores , Doenças das Artérias Carótidas , Lipidômica , Lipídeos , Placa Aterosclerótica , Espectrometria de Massas em Tandem , Humanos , Placa Aterosclerótica/sangue , Masculino , Feminino , Idoso , Lipídeos/sangue , Doenças das Artérias Carótidas/sangue , Doenças das Artérias Carótidas/diagnóstico , Biomarcadores/sangue , Pessoa de Meia-Idade , Cromatografia Líquida , Valor Preditivo dos Testes , Ruptura Espontânea , Idoso de 80 Anos ou mais , Estudos de Casos e ControlesRESUMO
Serial crystallography requires large numbers of microcrystals and robust strategies to rapidly apply substrates to initiate reactions in time-resolved studies. Here, we report the use of droplet miniaturization for the controlled production of uniform crystals, providing an avenue for controlled substrate addition and synchronous reaction initiation. The approach was evaluated using two enzymatic systems, yielding 3â µm crystals of lysozyme and 2â µm crystals of Pdx1, an Arabidopsis enzyme involved in vitamin B6 biosynthesis. A seeding strategy was used to overcome the improbability of Pdx1 nucleation occurring with diminishing droplet volumes. Convection within droplets was exploited for rapid crystal mixing with ligands. Mixing times of <2â ms were achieved. Droplet microfluidics for crystal size engineering and rapid micromixing can be utilized to advance time-resolved serial crystallography.
Assuntos
Arabidopsis , Microfluídica , Cristalografia , Cognição , ConvecçãoRESUMO
Binder H33 is a small protein binder engineered by ribosome display to bind human interleukin 10. Crystals of binder H33 display severe diffraction anisotropy. A set of data files with correction for diffraction anisotropy based on different local signal-to-noise ratios was prepared. Paired refinement was used to find the optimal anisotropic high-resolution diffraction limit of the data: 3.13-2.47â Å. The structure of binder H33 belongs to the 2% of crystal structures with the highest solvent content in the Protein Data Bank.
RESUMO
Background: Predicting stroke risk in patients with carotid artery stenosis (CS) remains challenging. Circulating biomarkers seem to provide improvements with respect to risk stratification. Methods: Study patients who underwent carotid endarterectomy were categorized into four groups according to symptomatology and compared as follows: symptomatic with asymptomatic patients; and asymptomatic patients including amaurosis fugax (AF) (asymptomatic + AF group) with patients with a transient ischemic attack (TIA) or brain stroke (BS) (hemispheric brain stroke group). Carotid specimens were histologically analyzed and classified based on the American Heart Classification (AHA) standard. As a marker of OS, the plasma levels of malondialdehyde (MDA) were measured. Comparisons of MDA plasma levels between groups were analyzed. Results: In total, 35 patients were included in the study. There were 22 (63%) patients in the asymptomatic group and 13 (37%) in the symptomatic group. Atheromatous plaque (p = 0.03) and old hemorrhage (p = 0.05), fibrous plaque (p = 0.04), myxoid changes (p = 0.02), plaques without hemorrhage (p = 0.04), significant neovascularization (p = 0.04) and AHA classification (p = 0.006) had significant correlations with clinical presentation. There were 26 (74%) patients in the asymptomatic group and 9 (26%) in the hemispheric brain stroke group. Atheromatous plaque (p = 0.02), old hemorrhage (p = 0.05) and plaques without neovascularization (p = 0.02), fibrous plaque (p = 0.03), plaques without hemorrhage (p = 0.02) and AHA classification (p = 0.01) had significant correlations with clinical presentation. There was no significant difference between symptomatic and asymptomatic groups with respect to MDA plasma levels (p = 0.232). A significant difference was observed when MDA plasma levels were compared to asymptomatic + AF and the hemispheric stroke group (p = 0.002). Conclusions: MDA plasma level correlates with the risk of hemispheric stroke (TIA or BS) and is a reliable marker of plaque vulnerability in carotid artery stenosis.
RESUMO
The resistance of the emerging human pathogen Stenotrophomonas maltophilia to tetracycline antibiotics mainly depends on multidrug efflux pumps and ribosomal protection enzymes. However, the genomes of several strains of this Gram-negative bacterium code for a FAD-dependent monooxygenase (SmTetX) homologous to tetracycline destructases. This protein was recombinantly produced and its structure and function were investigated. Activity assays using SmTetX showed its ability to modify oxytetracycline with a catalytic rate comparable to those of other destructases. SmTetX shares its fold with the tetracycline destructase TetX from Bacteroides thetaiotaomicron; however, its active site possesses an aromatic region that is unique in this enzyme family. A docking study confirmed tetracycline and its analogues to be the preferred binders amongst various classes of antibiotics.
Assuntos
Oxitetraciclina , Stenotrophomonas maltophilia , Humanos , Stenotrophomonas maltophilia/genética , Stenotrophomonas maltophilia/metabolismo , Cristalografia por Raios X , Antibacterianos/farmacologia , Antibacterianos/química , Tetraciclina/farmacologia , Tetraciclina/metabolismo , Oxitetraciclina/metabolismo , Testes de Sensibilidade MicrobianaRESUMO
The Collaborative Computational Project No. 4 (CCP4) is a UK-led international collective with a mission to develop, test, distribute and promote software for macromolecular crystallography. The CCP4 suite is a multiplatform collection of programs brought together by familiar execution routines, a set of common libraries and graphical interfaces. The CCP4 suite has experienced several considerable changes since its last reference article, involving new infrastructure, original programs and graphical interfaces. This article, which is intended as a general literature citation for the use of the CCP4 software suite in structure determination, will guide the reader through such transformations, offering a general overview of the new features and outlining future developments. As such, it aims to highlight the individual programs that comprise the suite and to provide the latest references to them for perusal by crystallographers around the world.
Assuntos
Proteínas , Software , Proteínas/química , Cristalografia por Raios X , Substâncias MacromolecularesRESUMO
Pregnancy-associated plasma protein-A (PAPP-A) was studied as a marker of acute coronary syndrome (ACS). It has been shown that its levels are increased by heparin administration. Therefore, the aim of our study was to ascertain the diagnostic significance of PAPP-A in heparin-naïve patients and compare it with (TnI). We prospectively studied 67 heparin-naïve patients with acute chest pain. The patients were independently grouped according to the presence or absence of ACS. PAPP-A levels were significantly increased in ACS patients (8.6 vs. 7.3 mIU/l; P = 0.006) with high positive (95.7%) and lower negative predictive values (47.7%). In multivariate analysis, its levels were strongly predictive of a final diagnosis of ACS (OR 41.8; 95th CI 2.64-662.6; P = 0.008). The diagnostic significance of PAPP-A was not higher than TnI even within 6 h after the onset of chest pain [the area under the ROC curve (AUC) was 0.69 for PAPP-A and 0.91 for TnI, respectively; P = 0.08]. We observed no difference in the AUC in NSTE-ACS patients (0.73 for PAPP-A and 0.79 for TnI (P = 0.5)). PAPP-A levels were an independent predictor of ACS diagnosis in heparin-naïve patients. Its diagnostic significance was not higher than TnI even within a short period after the onset of chest pain. In troponin-negative NSTE-ACS patients, PAPP-A helped make the correct final diagnosis.
Assuntos
Síndrome Coronariana Aguda/sangue , Síndrome Coronariana Aguda/diagnóstico , Heparina , Proteína Plasmática A Associada à Gravidez/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Troponina I/sangueRESUMO
One of the main limitations of laser powder bed fusion technology is the residual stress (RS) introduced into the material by the local heating of the laser beam. RS restricts the processability of some materials and causes shape distortions in the process. Powder bed preheating is a commonly used technique for RS mitigation. Therefore, the objective of this study was to investigate the effect of powder bed preheating in the range of room temperature to 400 °C on RS, macrostructure, microstructure, mechanical properties, and properties of the unfused powder of the nickel-based superalloy Inconel 939. The effect of base plate preheating on RS was determined by an indirect method using deformation of the bridge-shaped specimens. Inconel 939 behaved differently than titanium and aluminum alloys when preheated at high temperatures. Preheating at high temperatures resulted in higher RS, higher 0.2% proof stress and ultimate strength, lower elongation at brake, and higher material hardness. The increased RSs and the change in mechanical properties are attributed to changes in the microstructure. Preheating resulted in a larger melt pool, increased the width of columnar grains, and led to evolution of the carbide phase. The most significant microstructure change was in the increase of the size and occurrence of the carbide phase when higher preheating was applied. Furthermore, it was detected that the evolution of the carbide phase strongly corresponds to the build time when high-temperature preheating is applied. Rapid oxidation of the unfused powder was not detected by EDX or XRD analyses.
RESUMO
Lipids modified by oxidative stress are key players in atherosclerosis progression. Superimposed thrombosis with subsequent closure of the coronary artery leads to the clinical manifestation of acute coronary syndrome (ACS). While several studies focusing on alterations in lipid metabolism in the acute phase have been conducted, no information is available on patients' lipidome alterations over longer time periods. In the current follow-up study, we analyzed plasma samples obtained from 17 patients three years after their ACS event (group AC). Originally, these patients were sampled 3-5 days after an index event (group B). Lipidome stability over time was studied by untargeted lipidomics using high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-HRMS). Multi-dimensional statistics used for data processing indicated that plasmalogen lipids were the most prominent lipids separating the above patient groups and that they increased in the follow-up AC group. A similar trend was observed for lysophosphatidylethanolamine (LPE) and phosphatidylethanolamine (PE). The opposite trend was observed for two fatty acyls of hydroxy fatty acid (FAHFAs) lipids and free stearic acid. In addition, a decrease in the "classic" oxitadive stress marker, malondialdehyde (MDA), occurred during the follow-up period. Our findings present unique information about long-term lipidome changes in patients after ACS.
RESUMO
S1 nuclease from Aspergillus oryzae is a single-strand-specific nuclease from the S1/P1 family that is utilized in biochemistry and biotechnology. S1 nuclease is active on both RNA and DNA but with differing catalytic efficiencies. This study clarifies its catalytic properties using a thorough comparison of differences in the binding of RNA and DNA in the active site of S1 nuclease based on X-ray structures, including two newly solved complexes of S1 nuclease with the products of RNA cleavage at atomic resolution. Conclusions derived from this comparison are valid for the whole S1/P1 nuclease family. For proper model building and refinement, multiple lattice-translocation defects present in the measured diffraction data needed to be solved. Two different approaches were tested and compared. Correction of the measured intensities proved to be superior to the use of the dislocation model of asymmetric units with partial occupancy of individual chains. As the crystals suffered from multiple lattice translocations, equations for their correction were derived de novo. The presented approach to the correction of multiple lattice-translocation defects may help to solve similar problems in the field of protein X-ray crystallography.
Assuntos
Aspergillus oryzae , RNA , Aspergillus oryzae/genética , Aspergillus oryzae/metabolismo , Domínio Catalítico , DNA , Endonucleases/química , RNA/metabolismoRESUMO
We describe the internal structure, spatial organization and dynamic formation of coronary artery thrombi from ST-segment elevation myocardial infarction patients. Scanning electron microscopy (SEM) revealed significant differences among four groups of patients (<2 hours; 2-6 hours; 6-12 hours, and >12 hours) related to the time of ischemia. Coronary artery thrombi from patients presenting less than 2 hours after the infarction were almost entirely composed of platelets, with small amounts of fibrin and red blood cells. In contrast, thrombi from late presenters (>12 hours) consisted of mainly platelets at the distal end, where clotting was initiated, with almost no platelets at the proximal end, while the red blood cell content went from low at the initiating end to more than 90% at the proximal end. Furthermore, fibrin was present mainly on the outside of the thrombi and older thrombi contained thicker fibers. The red blood cells in late thrombi were compressed to a close-packed, tessellated array of polyhedral structures, called polyhedrocytes. Moreover, there was redistribution from the originally homogeneous composition to fibrin and platelets to the outside, with polyhedrocytes on the interior. The presence of polyhedrocytes and the redistribution of components are signs of in vivo clot contraction (or retraction). These results suggest why later thrombi are resistant to fibrinolytic agents and other treatment modalities, since the close-packed polyhedrocytes form a nearly impermeable seal. Furthermore, it is of particular clinical significance that these findings suggest specific disparate therapies that will be most effective at different stages of thrombus development.
Assuntos
Plaquetas/patologia , Trombose Coronária , Eritrócitos/patologia , Fibrina/análise , Fibrinolíticos , Infarto do Miocárdio com Supradesnível do Segmento ST , Coagulação Sanguínea/efeitos dos fármacos , Coagulação Sanguínea/fisiologia , Trombose Coronária/diagnóstico por imagem , Trombose Coronária/tratamento farmacológico , Trombose Coronária/metabolismo , Trombose Coronária/patologia , Resistência a Medicamentos/fisiologia , Feminino , Fibrinolíticos/administração & dosagem , Fibrinolíticos/efeitos adversos , Humanos , Masculino , Microscopia Eletrônica de Varredura/métodos , Pessoa de Meia-Idade , Infarto do Miocárdio com Supradesnível do Segmento ST/etiologia , Infarto do Miocárdio com Supradesnível do Segmento ST/terapia , Trombectomia/métodos , Fatores de Tempo , Tempo para o TratamentoRESUMO
BACKGROUND: The aim of this proteomic study was to look for changes taking place in plasma proteomes of patients with acute myocardial infarction (AMI), unstable angina pectoris (UAP), and stable angina pectoris (SAP). METHODS: Depleted plasma proteins were separated by 2D SDS-PAGE (pI 4-7), and proteomes were compared using Progenesis SameSpots statistical software. Proteins were identified by nanoLC-MS/MS. Proteins were quantified using commercial kits. Apolipoprotein A1 was studied using 1D and 2D SDS-PAGE, together with western blotting. RESULTS: Reciprocal comparison revealed 46 unique, significantly different spots; proteins in 34 spots were successfully identified and corresponded to 38 different proteins. Discrete comparisons of patient groups showed 45, 41, and 8 significantly different spots when AMI, UAP, and SAP were compared with the control group. On the basis of our proteomic data, plasma levels of two of them, alpha-1 microglobulin and vitamin D-binding protein, were determined. The data, however, failed to prove the proteins to be suitable markers or risk factors in the studied groups. The plasma level and isoform representation of apolipoprotein A1 were also estimated. Using 1D and 2D SDS-PAGE, together with western blotting, we observed extra high-molecular weight apolipoprotein A1 fractions presented only in the patient groups, indicating that the novel high-molecular weight isoforms of apolipoprotein A1 may be potential new markers or possible risk factors of cardiovascular disease. CONCLUSION: The reported data show plasma proteome changes in patients with AMI, UAP, and SAP. We propose some apolipoprotein A1 fractions as a possible new disease-associated marker of cardiovascular disorders.
Assuntos
Apolipoproteína A-I/sangue , Doenças Cardiovasculares/sangue , Proteoma/metabolismo , Idoso , Eletroforese em Gel Bidimensional , Feminino , Humanos , Masculino , Peso Molecular , Análise de Componente Principal , Isoformas de Proteínas/sangueRESUMO
BACKGROUND: Carotid artery stenting (CAS) is the method of choice for carotid artery revascularization of patients at high risk for carotid endarterectomy. In this study, we compared the midterm results of CAS in patients with unilateral versus bilateral carotid artery disease. METHODS AND RESULTS: This is a retrospective analysis of 1-year outcome of 273 consecutive patients in whom 342 CAS procedures were performed. The incidence of periprocedural transient ischemic attacks (TIAs) differed significantly (8% vs. 1%; p = 0.01) among patients with and without bilateral internal carotid disease, and a tendency to a lower occurrence of early adverse events (death, stroke, periprocedural TIA, periprocedural myocardial infarction) was subsequently shown (11% vs. 5%; p = 0.12). At 1-year follow-up, there was a high incidence of adverse events (death, stroke, periprocedural TIA, periprocedural myocardial infarction, restenosis) in patients with bilateral carotid artery disease (40% vs. 14%; p < 0.01), which was mainly driven by a higher incidence of death, periprocedural TIA, and restenosis (p ≤ 0.02 for all). According to multivariate analysis, the independent predictors of midterm adverse events were left ventricular dysfunction, male gender, bilateral carotid artery disease, renal insufficiency, cerebral symptoms within the last 6 months before the intervention, and low-density lipoprotein cholesterol level. CONCLUSIONS: At midterm follow-up, patients with bilateral carotid artery disease treated by CAS have significantly more adverse events than those with unilateral disease.