Cardiovascular disease (CVD) is a major cause of adult morbidity and mortality in developed as well as in developing countries. In black population groups, stroke is more prominent than ischaemic heart disease. This may be attributed to a combination of risk factors seen in this population group inter alia raised haemostatic markers, which favour the development of stroke since it is well known that a disturbance in the haemostatic balance (a hypercoagulable and a hypofibrinolytic state) predisposes to CVD. It is generally accepted that childhood genetic, environmental and behavioural factors lay the groundwork for the manifestation of adult CVD. Therefore, one of the studies that form part of this dissertation was a cross-sectional study to determine whether haemostatic abnormalities are already present in black African adolescents and to determine whether high risk groups exist [in relation to the following haemostatic markers: fibrinogen, factor VIII (FVIII), plasminogen activator inhibitor type 1 activity (PAI-Iact), and thrombin anti-thrombin complex (TAT)] for the development of CVD later in life. The population subdivisions were made according to gender, body fat %, maturity status, height for age Z-score, and habitual PA levels. Since behavioural factors [diet, physical activity (PA), smoking and drinking habits] are controllable determinants, it could be possible to improve CVD risk to a certain degree. Therefore, the second study that forms part of this dissertation attempted to establish whether a PA programme will successfully reduce haemostatic variables in a subset of the study population used in the first study. The reader is referred to the abstracts at the beginning of each separate study manuscript (Chapters 3 and 4), for a description of the subjects, study design and methods used in each study. The results of the cross-sectional study showed that in African adolescents (a) gender independently contributed to the variability in PAI-Iact, but that the gender difference in fibrinogen and TAT could be explained by the significant differences in fat mass and PA levels observed between the genders; (b) fibrinogen was significantly higher in the stunted compared to the non-stunted children indicating that childhood chronic malnutrition may possibly predispose independently to CVD; (c) fitness influences TAT concentrations positively and that (d) no significant differences in FVIII could be found between any of the subdivisions. As these determinants seem to be modifiable through behavioural changes and optimal nutrition status through early life, it raises a sense of urgency to develop strategies for the prevention and treatment of these risk factors. The results of the intervention study showed that an 11-week outdoor PA intervention programme had no significant effect on the haemostatic markers of African adolescents, but the results of this study should be interpreted with caution since (a) seasonal variations could have clouded the effect of the PA intervention as baseline measurements were taken in the summer and end measurements in the winter; (b) attendance of the PA sessions does not necessarily implicate compliance to the exercises given; (c) baseline values seem to play a prominent role in the changes that could be expected during an intervention and, therefore, improvements in the haemostatic profile would most likely be more significant in individuals with raised baseline levels. Similar research on African children is warranted since studies investigating PA's effect on haemostatic variables remain a topic of debate and speculation and data on African population groups are scanty. / Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2007

INTRODUÇÃO: O sangramento é complicação frequente durante e após cirurgias cardíacas pediátricas, com a hipofibrinogenemia adquirida responsável pela maioria dos casos de sangramento grave. O presente estudo avaliou o efeito do concentrado de fibrinogênio na redução do sangramento pós-operatório de cirurgia cardíaca congênita com circulação extracorpórea (CEC). MÉTODOS: Estudo prospectivo, randomizado e controlado com crianças submetidas à cirurgia cardíaca congênita. Critérios de inclusão: cirurgia cardíaca com circulação extracorpórea e idade menor de 28 dias de vida, ou RACHS-1 maior ou igual a 3 ou reoperação com idade menor de 10 anos, e FIBTEM A-10 menor que 15 mm. Os pacientes foram randomizados 1:1 para o grupo concentrado de fibrinogênio de acordo com a fórmula [delta-MCF FIBTEM (mm) x kg peso corporal / 140] ou para o grupo controle (soro fisiológico 0,9%). O objetivo primário deste estudo foi avaliar sangramento pós-operatório. Os objetivos secundários foram analisar a necessidade de transfusão alogênica, comparar o perfil do fibrinogênio e a ocorrência de complicações pós-operatórias entre os grupos. RESULTADOS: Foram randomizados 42 pacientes, 21 pacientes foram alocados para o grupo concentrado de fibrinogênio e 21 pacientes para o grupo controle. Em relação ao sangramento pós-operatório, os pacientes randomizados para concentrado de fibrinogênio apresentaram volume de drenagem sanguínea total menor quando comparados ao grupo controle [120 (95 - 180) vs. 210 (125 - 375) ml; p= 0,019)] e no 1º PO [50 (20 - 80) vs. 80 (47,5 - 120) ml; p= 0,014]. Não houve diferença entre os grupos em relação à transfusão intra-operatória (p= 0,343) e à transfusão pósoperatória (p= 0,109). Os níveis de fibrinogênio analisados pelo FIBTEM no tempo 0 (saída de CEC) foram similares entre os grupos (T0: 6,43 ± 1,60 mm vs. 6,86 ± 1,85 mm; p= 0,427). Não houve diferença em relação aos níveis de fibrinogênio, tanto nos resultados obtidos pela análise do FIBTEM A-10 (T1: 11,05 ± 3,43 vs. 7,52 ± 3,03 mm; p= 0,427) quanto pela análise plasmática [T1: 224 vs. 156 mg/dl (p= 0,158); T2: 208 vs. 179 mg/dl; p= 0,155] entre os grupos concentrado de fibrinogênio e controle, após a infusão da solução do estudo. Houve diferença significativa quanto à ventilação mecânica, o grupo concentrado de fibrinogênio apresentou tempo mais prolongado comparado ao grupo controle [11795 (3357 - 34972,5) min vs. 4850 (1130 - 9540) min; p= 0,015]. Além disso, houve uma incidência estatisticamente maior de baixo débito cardíaco no grupo concentrado de fibrinogênio comparado ao grupo controle (23,8% vs. 0%; p= 0,048). Em relação à ocorrência das demais complicações clínicas avaliadas em 28 dias, ao tempo de internação na UTI, tempo de internação hospitalar e mortalidade não houve diferença estatisticamente significante entre os grupos. CONCLUSÃO: Em crianças submetidas à cirurgia cardíaca, o uso profilático de concentrado de fibrinogênio reduziu o sangramento pós-operatório. Não houve diferença significativa entre os grupos em relação à transfusão intra e pós-operatória. O perfil do fibrinogênio não apresentou diferença entre os grupos. O grupo concentrado de fibrinogênio apresentou tempo de ventilação mecânica mais prolongado e maior incidência de síndrome de baixo débito cardíaco / INTRODUCTION: Bleeding is a common complication during and after pediatric cardiac surgery, with acquired hypofibrinogenemia being the most associated disorder. This trial evaluated whether the use of prophylactic fibrinogen concentrate reduces bleeding in congenital heart surgery with cardiopulmonary bypass (CPB). METHODS: Prospective, randomized, controlled study with children undergoing congenital heart surgery. Inclusion criteria: cardiac surgery with cardiopulmonary bypass and age under 28 days, or RACHS-1 >= 3 or reoperation with age under 10 years, and FIBTEM-A10 less than 15 mm. Patients were randomized 1:1 to the treatment group [fibrinogen concentrate according to the formula Detla-MCF FIBTEM (mm) x kg body weight / 140] or to the control group (saline 0.9%). The primary objective of this study was to evaluate postoperative bleeding. The secondary objectives were to analyze the need for allogeneic transfusion, to compare the plasmatic fibrinogen, FIBTEM A-10 levels and the occurrence of postoperative complications between the groups. RESULTS: Fortytwo patients were randomized, 21 patients were allocated to the fibrinogen concentrate group and 21 patients to the control group. Regarding postoperative bleeding, patients randomized to fibrinogen concentrate had a lower total blood drainage volume compared to the control group [120 (95 - 180) vs. 210 (125 - 375) ml; p= 0.019)] and lower bleeding in the 1st PO [50 (20 - 80) vs. 80 (47.5 - 120) ml; p= 0.014]. There were no differences between groups regarding intraoperative transfusion (p= 0.343) and postoperative transfusion (p= 0.109). The fibrinogen levels analyzed by FIBTEM at time 0 (after CPB) were similar between the fibrinogen and control concentrate groups (T0: 6.43 ± 1.60 mm vs. 6.86 ± 1.85 mm; p= 0.427). There was no difference in fibrinogen levels, either in the results obtained by FIBTEM A-10 analysis (T1: 11.05 ± 3.43 vs. 7.52 ± 3.03 mm; p= 0.427) or by Clauss analysis [T1: 224 vs. 156 mg/dl (p= 0.158); T2: 208 vs. 179 mg/dl; p= 0.155] between the fibrinogen concentrate and control groups, after intervention. There was a significant difference in mechanical ventilation, the fibrinogen concentrate group had prolonged time compared to the control group [11795 (3357 - 34972.5) min vs. 4850 (1130 - 9540) min; p= 0.015]. In addition, there was a statistically higher incidence of low cardiac output in the fibrinogen concentrate group compared to the control group (23.8% vs. 0%; p= 0.048). Regarding the occurrence of other clinical complications evaluated in 28 days, length of ICU stay, length of hospital stay and mortality, the groups did not present any difference. CONCLUSION: In children undergoing cardiac surgery, prophylactic use of fibrinogen concentrate reduced postoperative bleeding. There was no significant difference between the groups regarding intra and postoperative transfusion. The fibrinogen analysis had no difference between the groups. The fibrinogen concentrate group had a prolonged mechanical ventilation time and a higher incidence of low cardiac output syndrome among the complications

INTRODUÇÃO: a albumina sérica reduzida em pacientes em diálise peritoneal (DP) é associada à aterosclerose, causa de morte mais comum entre esses pacientes. Semelhantemente à síndrome nefrótica, supõe-se que a perda de proteínas conjuntamente a de fatores de regulação da hemostasia leva ao estímulo da síntese hepática de fatores pró-coagulantes, como o fibrinogênio, deslocando o equilíbrio hemostático em direção ao estado pró-trombótico. Pacientes em DP apresentam valores séricos elevados de marcadores da ativação endotelial e fatores pró-coagulantes, quando comparados a pacientes em hemodiálise (HD). A tromboelastografia (TEG) é um método que avalia propriedades do sangue global e dinâmica da coagulação, fornecendo, por meio de um traçado, valores absolutos do tempo de formação de fibrina (K), a agregação plaquetária (amplitude máxima - AM), a firmeza do coágulo (G), entre outros dados. Por final, classifica a coagulação em normal, hipocoagulante ou hipercoagulante segundo o índice de coagulação (IC) apresentado, sendo assim útil no diagnóstico precoce de coagulopatias. Por ser pouco utilizado em pacientes com DRC, utilizou-se o TEG na avaliação da hemostasia dos pacientes em diálise peritoneal automatizada (DPA) e investigou-se a relação com a perda de proteínas, bem como outras condições clínicas inerentes ao tratamento dialítico. MÉTODOS: este estudo foi do tipo transversal que incluiu pacientes estáveis em DPA. Foram obtidos dados demográficos, clínicos e bioquímicos de rotina do prontuário médico eletrônico. Adicionalmente, foram avaliados a coagulometria, a hemostasia primária [antitrombina (AT), proteína S, fator VIII (FVIII), fator IX (FIX), fator V (FV), fibrinogênio e dímero-D] e o TEG. Os pacientes foram submetidos ao teste de equilíbrio peritoneal (PET), a avaliação da perda de proteínas para a solução de diálise (PSD) e a absorção de glicose. O estado nutricional dos pacientes foi avaliado por meio de métodos objetivos e subjetivos. RESULTADOS: vinte pacientes (38±16 anos de idade, 55% mulheres, 22,4±14,8 meses em DPA, 40% de glomerulopatia, 70% transportadores médio lento/lento e em bom estado nutricional) foram incluídos no estudo. O FVIII e FIX elevados em 85% e 50% da amostra, respectivamente. O fibrinogênio (553,8±100,5 mg/dL) e o dímero-D (720 (520-1940) ug/L) foram elevados em mais da metade dos pacientes. O TEG revelou 55% dos pacientes hipercoagulantes, 45%, normais, e nenhum era hipocoagulante. Os pacientes hipercoagulantes foram caracterizados por um tempo K menor (1,3±0,4 vs. 1,8±0,3 minutos, p=0,007); AM (72,1±2,4 vs. 64,7±3,6 mm, p=0,000) e G (13,1±1,6 vs. 9,3±1,5 K, p= p=0,000) elevados, também alterados em 78% e 33%, respectivamente, nos pacientes com coagulação normal. Pacientes hipercoagulantes também apresentaram maiores valores de plaquetas (251±28 vs. 214±51 mil/mm³, p=0,038), que se correlacionou positivamente com AM/G (r=0,594, p=0,006), enquanto a proteína C foi menor (108±12 vs. 117±20 %, p=0,034) e a AT se correlacionou positivamente com o tempo K (r=0,635, p=0,011). Não houve diferença de albumina sérica, PSD, cinética de creatinina e estado nutricional entre os grupos normal e hipercoagulante. Os pacientes hipercoagulantes, entretanto, apresentaram menores valores de hemoglobina (10,3±1,4 g/dL vs. 12,0±1,1 g/dL; p=0,007), que se correlacionou negativamente com AM/G (r=-0,673, p=0,001), bem como o hematócrito (31±4 % vs. 36±3 %; p=0,010), que também se correlacionou negativamente com AM/G (r=-0,640; p=0,002). CONCLUSÃO: demonstramos que pacientes em DPA estáveis apresentaram uma tendência pró-trombótica caracterizada pela hiperfunção plaquetária e maior força de coágulo. Mesmo não havendo linearidade na relação com a hemostasia a perda de proteínas pode ter contribuído para a hipercoagulabilidade nesses pacientes. Entretanto, os eritrócitos reduzidos representaram um fator de confusão para o resultado do / INTRODUCTION: reduced serum albumin in patients on peritoneal dialysis (PD) is associated to atherosclerosis that is the leading cause of death. Similarly to nephrotic syndrome they lose protein; it is assumed that together with regulating factors of haemostasis this loss leads to liver synthesizes of procoagulants factors, such as fibrinogen, shifting the hemostatic equilibrium to a prothrombotic state. Patients on PD present elevated serum markers of endothelial activation and coagulant factors when compared with hemodialysis (HD) patients. Thromboelastography (TEG) is a method that evaluate blood properties through coagulation\'s global and dynamic perspectives, providing through a trace absolute values of fibrin\'s time formation (K), platelet aggregation (maximum amplitude - MA), clot strength (G), among other data. Finally it classifies the coagulation in normal, hypocoagulant or hypercoagulant according to the coagulation index (CI), so that it is useful in the early diagnosis of coagulopathies. TEG is not often used in patients with CKD, because of this we chose to use TEG for hemostatic evaluation in patients on APD and investigated its relation with protein loss as well as other clinical conditions intrinsic to the dialytic therapy. METHODS: this was a cross-sectional study that included stable patients on automated peritoneal dialysis (APD). Demographic, clinical and routine biochemical data were obtained from electronic medical chart. Additionally the coagulometry, primary hemostasis [antithrombin (AT), protein S, factor VIII (FVIII), factor IX (FIX), factor V (FV), fibrinogen and D-dimer] and TEG were evaluated. Patients were submitted to peritoneal equilibrium test (PET), protein loss to dialysis solution (PDS) and glucose absorption evaluations. Patients nutritional status was evaluated by objective and subjective methods. RESULTS: twenty patients (38±16 years old, 55% women, 22.4±14.8 months on APD, 40% of glomerulopathy, 70% slow average/slow transporters and well nourished) were included in this study. FVIII and FIX were elevated in 85% and 50% of the sample, respectively. Fibrinogen (553.8±100.5 mg/dL) and D-dimer (720 (520-1940) ug/L) were elevated in over half of the patients. TEG showed 55% of the patients hypercoagulant, 45% were normal and nobody was hypocoagulant. Hypercoagulant patients were characterized by a lower K-time (1.3±0.4 vs. 1.8±0.3 minutes; p=0.007); elevated MA (72.1±2.4 vs. 64.7±3.6 mm; p=0.000) and G (13.1±1.6 vs. 9.3±1.5 K; p= p=0.000); altered too in 78% and 33%, respectively, in normal coagulation patients. Hypercoagulant patients presented too higher values of platelet count (251±28 vs. 214±51 mil/mm³, p=0,038), but within the normal range, that correlated positively with MA/G (r=0.594; p=0.006) while protein C was lower (108±12 vs. 117±20 %; p=0,034) and AT correlated positively with K-time (r=0.635; p=0.011). There was no difference to serum albumin, PDS, creatinin kinetic and nutritional status between hypercoagulant and normal groups. However hypercoagulant patients presented lower values of hemoglobin (10.3±1.4 g/dL vs. 12.0±1.1 g/dL; p=0.007); that correlated negatively with MA/G (r=-0.673; p=0.001), as well as hematocrit (31±4 % vs. 36±3 %; p=0,010), which also correlated negatively with MA/G (r=-0.640; p=0.002). CONCLUSION: we demonstrated that stable patients on APD presented a prothrombotic tendency characterized by platelet hyperfuntion and clot strength. Even though there was no linearity in relation to hemostasis; protein loss may have contributed to the hypercoagulability in these patients. However reduced erythrocytes were a confounding factor in the TEG analysis

Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2007.

Radiofrequency catheter ablation (RFA) is a rapidly developing, minimally invasive method of treatment for heart arrhythmias. Its employment is however limited due to complications, including thromboembolic ones. The basic of seven objectives of this dissertation were to: 1. by using different agonists of aggregation, to evaluate alteration of platelet aggregation in the venous blood and platelet-rich plasma, fibrinogen and D-dimer levels before RFA, immediately after, 24 hours and 72 hours after RFA under the influence of RFA in patients suffering from heart arrhythmia; 2. to establish the influence of the total RFA energy, structural heart disease, antithrombotic medicines know in the alteration of platelet aggregation induced by different agonists and in the alteration before RFA, immediately after and 24 hours after RFA. The obtained data show that changes in PA after RFA depended on whether PA proceeded in the venous blood or plasma and on the agonist used to induce aggregation. According to the results, PA is suppressed immediately after RFA and increases in 24 hours. The level of the applied total energy had an effect on changes in platelet aggregation after RFA. The dynamics of PA in patients with and without a structural heart disease were similar. The obtained pre-RFA values of PA were lower in blood and even lower in plasma in the group of patients who used aspirin, as compared to those who used low molecular mass heparin or no antithrombotic medicines. Despite the... [to full text]

Cardiovascular disease (CVD) is a major cause of adult morbidity and mortality in developed as well as in developing countries. In black population groups, stroke is more prominent than ischaemic heart disease. This may be attributed to a combination of risk factors seen in this population group inter alia raised haemostatic markers, which favour the development of stroke since it is well known that a disturbance in the haemostatic balance (a hypercoagulable and a hypofibrinolytic state) predisposes to CVD. It is generally accepted that childhood genetic, environmental and behavioural factors lay the groundwork for the manifestation of adult CVD. Therefore, one of the studies that form part of this dissertation was a cross-sectional study to determine whether haemostatic abnormalities are already present in black African adolescents and to determine whether high risk groups exist [in relation to the following haemostatic markers: fibrinogen, factor VIII (FVIII), plasminogen activator inhibitor type 1 activity (PAI-Iact), and thrombin anti-thrombin complex (TAT)] for the development of CVD later in life. The population subdivisions were made according to gender, body fat %, maturity status, height for age Z-score, and habitual PA levels. Since behavioural factors [diet, physical activity (PA), smoking and drinking habits] are controllable determinants, it could be possible to improve CVD risk to a certain degree. Therefore, the second study that forms part of this dissertation attempted to establish whether a PA programme will successfully reduce haemostatic variables in a subset of the study population used in the first study. The reader is referred to the abstracts at the beginning of each separate study manuscript (Chapters 3 and 4), for a description of the subjects, study design and methods used in each study. The results of the cross-sectional study showed that in African adolescents (a) gender independently contributed to the variability in PAI-Iact, but that the gender difference in fibrinogen and TAT could be explained by the significant differences in fat mass and PA levels observed between the genders; (b) fibrinogen was significantly higher in the stunted compared to the non-stunted children indicating that childhood chronic malnutrition may possibly predispose independently to CVD; (c) fitness influences TAT concentrations positively and that (d) no significant differences in FVIII could be found between any of the subdivisions. As these determinants seem to be modifiable through behavioural changes and optimal nutrition status through early life, it raises a sense of urgency to develop strategies for the prevention and treatment of these risk factors. The results of the intervention study showed that an 11-week outdoor PA intervention programme had no significant effect on the haemostatic markers of African adolescents, but the results of this study should be interpreted with caution since (a) seasonal variations could have clouded the effect of the PA intervention as baseline measurements were taken in the summer and end measurements in the winter; (b) attendance of the PA sessions does not necessarily implicate compliance to the exercises given; (c) baseline values seem to play a prominent role in the changes that could be expected during an intervention and, therefore, improvements in the haemostatic profile would most likely be more significant in individuals with raised baseline levels. Similar research on African children is warranted since studies investigating PA's effect on haemostatic variables remain a topic of debate and speculation and data on African population groups are scanty. / Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2007

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A ocorrência de fenótipos multirresistentes de Corynebacterium pseudodiphtheriticum e sua associação a infecções graves, com elevada mortalidade em pacientes imunocomprometidos, aliados ao escasso conhecimento da virulência e patogenia destas infecções, motivou esta pesquisa, que teve como objetivo investigar mecanismos de virulência e resistência microbiana deste agente entre pacientes de um hospital universitário brasileiro. Um total de 113 amostras de C. pseudodiphtheriticum identificadas por métodos bioquímicos convencionais e sistema API-Coryne isoladas de pacientes de diferentes grupos etários. Os micro-organismos eram, em sua maioria, relacionados a infecções no trato respiratório (27,45%), urinário (29,20%) e sitios intravenosos (18,60%) e cerca de 32,70% das amostras foram provenientes de pacientes com pelo menos uma das condições predisponentes: insuficiência renal; transplante renal, tuberculose em paciente HIV+, câncer, cirrose hepática, hemodiálise e uso de cateter. As amostras testadas revelaram-se multirresistentes sendo a maioria resistente à oxacilina, eritromicina e clindamicina. A adesão das cepas ao poliestireno e ao poliuretano indicou o envolvimento de hidrofobicidade da superfície celular na fase inicial da formação de biofilmes. O crescimento subsequente conduziu à formação de microcolônias, agregados bacterianos densos incorporados na matriz exopolimérica rodeada por espaços vazios, típica de biofilmes maduros. Adicionalmente, a interação do micro-organismo com fibrinogênio e fibronectina humana indica o envolvimento destes componentes séricos na formação de biofilme, sugerindo a participação de diferentes adesinas neste processo e a capacidade deste agente formar biofilme in vivo. A afinidade por esses componentes e a formação de biofilme podem contribuir para o estabelecimento e disseminação da infecção no hospedeiro. Adicionalmente, as cepas de C. pseudodiphtheriticum isoladas de pacientes com infecções localizadas (ATCC10700/Pharyngitis) e sistêmicas (HHC1507/Bacteremia) exibiram um padrão de aderência agregativa-like a células HEp-2, caracterizado por aglomerados de bactérias com aparência de um "empilhado de tijolos". Através do teste FAS e ensaios de interação na presença de inibidores de citoesqueleto, demonstramos o envolvimento da polimerização de actina na internalização das cepas testadas. A internalização bacteriana e rearranjo do citoesqueleto pareceu ser parcialmente desencadeado pela ativação da tirosina-quinase. Finalmente, C. pseudodiphtheriticum foi capaz de sobreviver no ambiente intracelular e embora não tenha demonstrado capacidade de replicar intracelularmente, células HEp-2 foram incapazes de eliminar o patógeno completamente no ambiente extracelular no período de 24 horas. Todas as cepas estudadas foram capazes de induzir apoptose em células epiteliais 24 horas pós-infecção evidenciada pelo aumento significativo no número de células mortas e pela ocorrência de alterações nucleares reveladas através dos métodos de coloração pelo azul Trypan, pelo DAPI e microscopia electrônica de transmissão. Alterações morfológicas incluindo a vacuolização, a fragmentação nuclear e a formação de corpos apoptóticos foram observadas neste período. A citometria de fluxo demonstrou ainda uma diminuição significativa no tamanho das células infectadas e a utilização de dupla marcação (iodeto de propídio / anexina V) permitiu a detecção da ocorrência de necrose e apoptose tardia. Em conclusão, o conhecimento de tais características contribuiu para a compreensão de mecanismos envolvidos no aumento da frequência de infecções graves com elevada mortalidade em pacientes no ambiente hospitalar, por C. pseudodiphtheriticum, um patógeno rotineiramente subestimado em países em desenvolvimento. / The occurrence of multiresistant phenotypes and associated with severe infections, with high mortality in immunocompromised hosts due to Corynebacterium pseudodiphtheriticum, allied to little known about virulence and pathogenesis these infections, led to present investigation. The investigation aims to examine the virulence mechanisms and resistance to antimicrobial agents of C. pseudodiphtheriticum among patients with bacterial infections at a Brazilian teaching hospital. A total of 113 C. pseudodiphtheriticum strains identified by conventional biochemical methods and API-Coryne System were recovered from patients from different age groups. Micro-organisms were mostly related to infections in the respiratory tracts (27.45%), urinary (29.20%) and intravenous sites (18.60%) and approximately 32.70% samples were obtained of patients presenting at least one of the pre-disposing conditions: end-stage renal disease; renal transplant; AIDS and Mycobacterium tuberculosis infection; cancer, hepatic cirrhosis; haemodialysis and catheter use. Antimicrobial susceptibility tests identified multiresistant phenotypes. Most strains were resistant to oxacillin, erythromycin and clindamycin. Adherence to polystyrene and polyurethane indicated the involvement of cell surface hydrophobicity in the initial stage of biofilm formation. Further growth led to the formation of dense bacterial aggregates embedded in the exopolymeric matrix surrounded by voids, typical of mature biofilms. Data also showed C. pseudodiphtheriticum recognizing human fibrinogen (Fbg) and fibronectin (Fn) and involvement of these sera components in biofilm formation in conditioning films. These findings suggest that biofilm formation may be associated with the expression of different adhesins. C. pseudodiphtheriticum may form biofilm in vivo possibly by an adherent biofilm mode of growth in vitro currently demonstrated on hydrophilic and hydrophobic abiotic surfaces. The affinity to Fbg and Fn and the biofilm-forming ability may contribute to the establishment and dissemination of infection caused by C. pseudodiphtheriticum. Additionally, C. pseudodiphtheriticum strains isolated from patients with localized (ATCC10700/Pharyngitis) and systemic (HHC1507/Bacteremia) infections exhibited an aggregative adherence-like pattern to HEp-2 cells characterized by clumps of bacteria with a stacked-brick appearance. The fluorescent actin staining test demonstrated that actin polymerization is involved in the internalization of the C. pseudodiphtheriticum strains. Bacterial internalization and cytoskeletal rearrangement seemed to be partially triggered by the activation of tyrosine kinase activity. Although C. pseudodiphtheriticum strains did not demonstrate an ability to replicate intracellularly, HEp-2 cells were unable to fully clear the pathogen within 24 hours. All samples were able to induce apoptosis in HEp-2 cells 24 h post-infection, evidenced by significant increase in the number of dead cells and nuclear alterations were observed by the Trypan blue assay, DAPI and transmission electron microscopy. Morphological changes in HEp-2 cells observed 24 h post-infection included vacuolization, nuclear fragmentation and the formation of apoptotic bodies. Flow cytometry revealed an significant decrease in cell size of infected HEp-2 cells. Furthermore, a double-staining assay using Propidium Iodide/Annexin V gave information about the numbers of vital vs. early apoptotic cells and late apoptotic or secondary necrotic cells. In conclusion, these characteristics may contribute to understanding of mechanisms involved on increase of severe infection, with high mortality in nosocomial enviroment patients by C. pseudodiphtheriticum, a pathogen usually overlooked in emerging countries.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A ocorrência de fenótipos multirresistentes de Corynebacterium pseudodiphtheriticum e sua associação a infecções graves, com elevada mortalidade em pacientes imunocomprometidos, aliados ao escasso conhecimento da virulência e patogenia destas infecções, motivou esta pesquisa, que teve como objetivo investigar mecanismos de virulência e resistência microbiana deste agente entre pacientes de um hospital universitário brasileiro. Um total de 113 amostras de C. pseudodiphtheriticum identificadas por métodos bioquímicos convencionais e sistema API-Coryne isoladas de pacientes de diferentes grupos etários. Os micro-organismos eram, em sua maioria, relacionados a infecções no trato respiratório (27,45%), urinário (29,20%) e sitios intravenosos (18,60%) e cerca de 32,70% das amostras foram provenientes de pacientes com pelo menos uma das condições predisponentes: insuficiência renal; transplante renal, tuberculose em paciente HIV+, câncer, cirrose hepática, hemodiálise e uso de cateter. As amostras testadas revelaram-se multirresistentes sendo a maioria resistente à oxacilina, eritromicina e clindamicina. A adesão das cepas ao poliestireno e ao poliuretano indicou o envolvimento de hidrofobicidade da superfície celular na fase inicial da formação de biofilmes. O crescimento subsequente conduziu à formação de microcolônias, agregados bacterianos densos incorporados na matriz exopolimérica rodeada por espaços vazios, típica de biofilmes maduros. Adicionalmente, a interação do micro-organismo com fibrinogênio e fibronectina humana indica o envolvimento destes componentes séricos na formação de biofilme, sugerindo a participação de diferentes adesinas neste processo e a capacidade deste agente formar biofilme in vivo. A afinidade por esses componentes e a formação de biofilme podem contribuir para o estabelecimento e disseminação da infecção no hospedeiro. Adicionalmente, as cepas de C. pseudodiphtheriticum isoladas de pacientes com infecções localizadas (ATCC10700/Pharyngitis) e sistêmicas (HHC1507/Bacteremia) exibiram um padrão de aderência agregativa-like a células HEp-2, caracterizado por aglomerados de bactérias com aparência de um "empilhado de tijolos". Através do teste FAS e ensaios de interação na presença de inibidores de citoesqueleto, demonstramos o envolvimento da polimerização de actina na internalização das cepas testadas. A internalização bacteriana e rearranjo do citoesqueleto pareceu ser parcialmente desencadeado pela ativação da tirosina-quinase. Finalmente, C. pseudodiphtheriticum foi capaz de sobreviver no ambiente intracelular e embora não tenha demonstrado capacidade de replicar intracelularmente, células HEp-2 foram incapazes de eliminar o patógeno completamente no ambiente extracelular no período de 24 horas. Todas as cepas estudadas foram capazes de induzir apoptose em células epiteliais 24 horas pós-infecção evidenciada pelo aumento significativo no número de células mortas e pela ocorrência de alterações nucleares reveladas através dos métodos de coloração pelo azul Trypan, pelo DAPI e microscopia electrônica de transmissão. Alterações morfológicas incluindo a vacuolização, a fragmentação nuclear e a formação de corpos apoptóticos foram observadas neste período. A citometria de fluxo demonstrou ainda uma diminuição significativa no tamanho das células infectadas e a utilização de dupla marcação (iodeto de propídio / anexina V) permitiu a detecção da ocorrência de necrose e apoptose tardia. Em conclusão, o conhecimento de tais características contribuiu para a compreensão de mecanismos envolvidos no aumento da frequência de infecções graves com elevada mortalidade em pacientes no ambiente hospitalar, por C. pseudodiphtheriticum, um patógeno rotineiramente subestimado em países em desenvolvimento. / The occurrence of multiresistant phenotypes and associated with severe infections, with high mortality in immunocompromised hosts due to Corynebacterium pseudodiphtheriticum, allied to little known about virulence and pathogenesis these infections, led to present investigation. The investigation aims to examine the virulence mechanisms and resistance to antimicrobial agents of C. pseudodiphtheriticum among patients with bacterial infections at a Brazilian teaching hospital. A total of 113 C. pseudodiphtheriticum strains identified by conventional biochemical methods and API-Coryne System were recovered from patients from different age groups. Micro-organisms were mostly related to infections in the respiratory tracts (27.45%), urinary (29.20%) and intravenous sites (18.60%) and approximately 32.70% samples were obtained of patients presenting at least one of the pre-disposing conditions: end-stage renal disease; renal transplant; AIDS and Mycobacterium tuberculosis infection; cancer, hepatic cirrhosis; haemodialysis and catheter use. Antimicrobial susceptibility tests identified multiresistant phenotypes. Most strains were resistant to oxacillin, erythromycin and clindamycin. Adherence to polystyrene and polyurethane indicated the involvement of cell surface hydrophobicity in the initial stage of biofilm formation. Further growth led to the formation of dense bacterial aggregates embedded in the exopolymeric matrix surrounded by voids, typical of mature biofilms. Data also showed C. pseudodiphtheriticum recognizing human fibrinogen (Fbg) and fibronectin (Fn) and involvement of these sera components in biofilm formation in conditioning films. These findings suggest that biofilm formation may be associated with the expression of different adhesins. C. pseudodiphtheriticum may form biofilm in vivo possibly by an adherent biofilm mode of growth in vitro currently demonstrated on hydrophilic and hydrophobic abiotic surfaces. The affinity to Fbg and Fn and the biofilm-forming ability may contribute to the establishment and dissemination of infection caused by C. pseudodiphtheriticum. Additionally, C. pseudodiphtheriticum strains isolated from patients with localized (ATCC10700/Pharyngitis) and systemic (HHC1507/Bacteremia) infections exhibited an aggregative adherence-like pattern to HEp-2 cells characterized by clumps of bacteria with a stacked-brick appearance. The fluorescent actin staining test demonstrated that actin polymerization is involved in the internalization of the C. pseudodiphtheriticum strains. Bacterial internalization and cytoskeletal rearrangement seemed to be partially triggered by the activation of tyrosine kinase activity. Although C. pseudodiphtheriticum strains did not demonstrate an ability to replicate intracellularly, HEp-2 cells were unable to fully clear the pathogen within 24 hours. All samples were able to induce apoptosis in HEp-2 cells 24 h post-infection, evidenced by significant increase in the number of dead cells and nuclear alterations were observed by the Trypan blue assay, DAPI and transmission electron microscopy. Morphological changes in HEp-2 cells observed 24 h post-infection included vacuolization, nuclear fragmentation and the formation of apoptotic bodies. Flow cytometry revealed an significant decrease in cell size of infected HEp-2 cells. Furthermore, a double-staining assay using Propidium Iodide/Annexin V gave information about the numbers of vital vs. early apoptotic cells and late apoptotic or secondary necrotic cells. In conclusion, these characteristics may contribute to understanding of mechanisms involved on increase of severe infection, with high mortality in nosocomial enviroment patients by C. pseudodiphtheriticum, a pathogen usually overlooked in emerging countries.

INTRODUÇÃO: a albumina sérica reduzida em pacientes em diálise peritoneal (DP) é associada à aterosclerose, causa de morte mais comum entre esses pacientes. Semelhantemente à síndrome nefrótica, supõe-se que a perda de proteínas conjuntamente a de fatores de regulação da hemostasia leva ao estímulo da síntese hepática de fatores pró-coagulantes, como o fibrinogênio, deslocando o equilíbrio hemostático em direção ao estado pró-trombótico. Pacientes em DP apresentam valores séricos elevados de marcadores da ativação endotelial e fatores pró-coagulantes, quando comparados a pacientes em hemodiálise (HD). A tromboelastografia (TEG) é um método que avalia propriedades do sangue global e dinâmica da coagulação, fornecendo, por meio de um traçado, valores absolutos do tempo de formação de fibrina (K), a agregação plaquetária (amplitude máxima - AM), a firmeza do coágulo (G), entre outros dados. Por final, classifica a coagulação em normal, hipocoagulante ou hipercoagulante segundo o índice de coagulação (IC) apresentado, sendo assim útil no diagnóstico precoce de coagulopatias. Por ser pouco utilizado em pacientes com DRC, utilizou-se o TEG na avaliação da hemostasia dos pacientes em diálise peritoneal automatizada (DPA) e investigou-se a relação com a perda de proteínas, bem como outras condições clínicas inerentes ao tratamento dialítico. MÉTODOS: este estudo foi do tipo transversal que incluiu pacientes estáveis em DPA. Foram obtidos dados demográficos, clínicos e bioquímicos de rotina do prontuário médico eletrônico. Adicionalmente, foram avaliados a coagulometria, a hemostasia primária [antitrombina (AT), proteína S, fator VIII (FVIII), fator IX (FIX), fator V (FV), fibrinogênio e dímero-D] e o TEG. Os pacientes foram submetidos ao teste de equilíbrio peritoneal (PET), a avaliação da perda de proteínas para a solução de diálise (PSD) e a absorção de glicose. O estado nutricional dos pacientes foi avaliado por meio de métodos objetivos e subjetivos. RESULTADOS: vinte pacientes (38±16 anos de idade, 55% mulheres, 22,4±14,8 meses em DPA, 40% de glomerulopatia, 70% transportadores médio lento/lento e em bom estado nutricional) foram incluídos no estudo. O FVIII e FIX elevados em 85% e 50% da amostra, respectivamente. O fibrinogênio (553,8±100,5 mg/dL) e o dímero-D (720 (520-1940) ug/L) foram elevados em mais da metade dos pacientes. O TEG revelou 55% dos pacientes hipercoagulantes, 45%, normais, e nenhum era hipocoagulante. Os pacientes hipercoagulantes foram caracterizados por um tempo K menor (1,3±0,4 vs. 1,8±0,3 minutos, p=0,007); AM (72,1±2,4 vs. 64,7±3,6 mm, p=0,000) e G (13,1±1,6 vs. 9,3±1,5 K, p= p=0,000) elevados, também alterados em 78% e 33%, respectivamente, nos pacientes com coagulação normal. Pacientes hipercoagulantes também apresentaram maiores valores de plaquetas (251±28 vs. 214±51 mil/mm³, p=0,038), que se correlacionou positivamente com AM/G (r=0,594, p=0,006), enquanto a proteína C foi menor (108±12 vs. 117±20 %, p=0,034) e a AT se correlacionou positivamente com o tempo K (r=0,635, p=0,011). Não houve diferença de albumina sérica, PSD, cinética de creatinina e estado nutricional entre os grupos normal e hipercoagulante. Os pacientes hipercoagulantes, entretanto, apresentaram menores valores de hemoglobina (10,3±1,4 g/dL vs. 12,0±1,1 g/dL; p=0,007), que se correlacionou negativamente com AM/G (r=-0,673, p=0,001), bem como o hematócrito (31±4 % vs. 36±3 %; p=0,010), que também se correlacionou negativamente com AM/G (r=-0,640; p=0,002). CONCLUSÃO: demonstramos que pacientes em DPA estáveis apresentaram uma tendência pró-trombótica caracterizada pela hiperfunção plaquetária e maior força de coágulo. Mesmo não havendo linearidade na relação com a hemostasia a perda de proteínas pode ter contribuído para a hipercoagulabilidade nesses pacientes. Entretanto, os eritrócitos reduzidos representaram um fator de confusão para o resultado do / INTRODUCTION: reduced serum albumin in patients on peritoneal dialysis (PD) is associated to atherosclerosis that is the leading cause of death. Similarly to nephrotic syndrome they lose protein; it is assumed that together with regulating factors of haemostasis this loss leads to liver synthesizes of procoagulants factors, such as fibrinogen, shifting the hemostatic equilibrium to a prothrombotic state. Patients on PD present elevated serum markers of endothelial activation and coagulant factors when compared with hemodialysis (HD) patients. Thromboelastography (TEG) is a method that evaluate blood properties through coagulation\'s global and dynamic perspectives, providing through a trace absolute values of fibrin\'s time formation (K), platelet aggregation (maximum amplitude - MA), clot strength (G), among other data. Finally it classifies the coagulation in normal, hypocoagulant or hypercoagulant according to the coagulation index (CI), so that it is useful in the early diagnosis of coagulopathies. TEG is not often used in patients with CKD, because of this we chose to use TEG for hemostatic evaluation in patients on APD and investigated its relation with protein loss as well as other clinical conditions intrinsic to the dialytic therapy. METHODS: this was a cross-sectional study that included stable patients on automated peritoneal dialysis (APD). Demographic, clinical and routine biochemical data were obtained from electronic medical chart. Additionally the coagulometry, primary hemostasis [antithrombin (AT), protein S, factor VIII (FVIII), factor IX (FIX), factor V (FV), fibrinogen and D-dimer] and TEG were evaluated. Patients were submitted to peritoneal equilibrium test (PET), protein loss to dialysis solution (PDS) and glucose absorption evaluations. Patients nutritional status was evaluated by objective and subjective methods. RESULTS: twenty patients (38±16 years old, 55% women, 22.4±14.8 months on APD, 40% of glomerulopathy, 70% slow average/slow transporters and well nourished) were included in this study. FVIII and FIX were elevated in 85% and 50% of the sample, respectively. Fibrinogen (553.8±100.5 mg/dL) and D-dimer (720 (520-1940) ug/L) were elevated in over half of the patients. TEG showed 55% of the patients hypercoagulant, 45% were normal and nobody was hypocoagulant. Hypercoagulant patients were characterized by a lower K-time (1.3±0.4 vs. 1.8±0.3 minutes; p=0.007); elevated MA (72.1±2.4 vs. 64.7±3.6 mm; p=0.000) and G (13.1±1.6 vs. 9.3±1.5 K; p= p=0.000); altered too in 78% and 33%, respectively, in normal coagulation patients. Hypercoagulant patients presented too higher values of platelet count (251±28 vs. 214±51 mil/mm³, p=0,038), but within the normal range, that correlated positively with MA/G (r=0.594; p=0.006) while protein C was lower (108±12 vs. 117±20 %; p=0,034) and AT correlated positively with K-time (r=0.635; p=0.011). There was no difference to serum albumin, PDS, creatinin kinetic and nutritional status between hypercoagulant and normal groups. However hypercoagulant patients presented lower values of hemoglobin (10.3±1.4 g/dL vs. 12.0±1.1 g/dL; p=0.007); that correlated negatively with MA/G (r=-0.673; p=0.001), as well as hematocrit (31±4 % vs. 36±3 %; p=0,010), which also correlated negatively with MA/G (r=-0.640; p=0.002). CONCLUSION: we demonstrated that stable patients on APD presented a prothrombotic tendency characterized by platelet hyperfuntion and clot strength. Even though there was no linearity in relation to hemostasis; protein loss may have contributed to the hypercoagulability in these patients. However reduced erythrocytes were a confounding factor in the TEG analysis