Investigating preoperative myoglobin level as predictive factor for acute kidney injury following cardiac surgery with cardiopulmonary bypass: a retrospective observational study

Abstract Background: Early identification of patients at risk of AKI after cardiac surgery is of critical importance for optimizing perioperative management and improving outcomes. This study aimed to identify the association between preoperative myoglobin levels and postoperative acute kidney injury (AKI) in patients undergoing valve surgery or coronary artery bypass graft surgery (CABG) with cardiopulmonary bypass. Methods: This retrospective study included 293 patients aged over 17 years who underwent valve surgery or CABG with cardiopulmonary bypass. We excluded 87 patients as they met the exclusion criteria. Therefore, 206 patients were included in the final analysis. The patients' demographics as well as intraoperative and postoperative data were collected from electronic medical records. AKI was defined according to the Acute Kidney Injury Network classification system. Results: Of the 206 patients included in this study, 77 developed AKI. The patients who developed AKI were older, had a history of hypertension, underwent valve surgery with concomitant CABG, had lower preoperative hemoglobin levels, and experienced prolonged extracorporeal circulation (ECC) times. Multivariate logistic regression analysis revealed that preoperative myoglobin levels and ECC time were correlated with the development of AKI. A higher preoperative myoglobin level was an independent risk factor for the development of cardiac surgery-associated AKI. Conclusions: Higher preoperative myoglobin levels may enable physicians to identify patients at risk of developing AKI and optimize management accordingly.

Qualidade da carne de frangos da linhagem Label Rouge suplementados com minerais biocomplexados e criados em sistema alternativo / [Meat quality of Label Rouge lineage chicken supplemented with biocomplexed minerals and reared in an alternative system]

Objetivou-se avaliar a influência da suplementação com minerais biocomplexados sobre a qualidade da carne de frangos da linhagem Label Rouge, de ambos os sexos, criados em sistema alternativo. O delineamento experimental foi inteiramente ao acaso (DIC), disposto em esquema fatorial (3x2), sendo três dietas (controle; 0,50ppm de selênio; 0,40ppm de cromo) e dois sexos. Para a estabilidade lipídica, foi utilizado o DIC, disposto em esquema fatorial (3x2x2), sendo três dietas, dois sexos e dois tempos de armazenamento (zero e 12 meses). Os parâmetros avaliados no peito e na coxa foram: pH final, cor (L* - luminosidade, a* - índice de vermelho, b* - índice de amarelo, C* - índice de saturação e h* - ângulo de tonalidade), perda de peso por cozimento (PPC), força de cisalhamento (FC) e estabilidade lipídica. Além disso, foram avaliadas a proporção das formas químicas da mioglobina da coxa e a quantificação do conteúdo de selênio no peito. Não houve efeito isolado da dieta sobre os parâmetros físicos e químicos do peito e da coxa e sobre a concentração de selênio no peito. As fêmeas apresentaram médias superiores de L* (57,57), b* (10,55) e C* (10,60) do peito; e os machos de L* (55,09) da coxa. Entre os machos, as aves alimentadas com a dieta controle e com cromo expressaram valores superiores de FC da coxa em relação às suplementadas com selênio; para o tratamento com cromo, os machos apresentaram média superior de FC da coxa e, em contrapartida, para o tratamento com selênio, as fêmeas manifestaram a maior média. As amostras submetidas ao período de 12 meses de armazenamento mostraram maiores valores de substâncias reativas ao ácido tiobarbitúrico (TBARS) em ambos os cortes. A suplementação com cromo e selênio biocomplexados não provocou alterações na qualidade da carne; as fêmeas demonstraram melhores atributos de qualidade da carne.(AU)

The objective of the present study was to evaluate the influence of the supplementation with biocomplexed minerals on the quality of the meat of label Rouge lineage chicken, of both genders, reared in an alternative system. The experimental design was completely randomized (CRD) in a factorial scheme (3x2), with three diets (control; 0.50ppm of selenium; 0.40ppm of chromium) and two genders. For lipid stability, the CRD arranged in a factorial scheme (3x2x2) was used, being three diets, two genders and two storage times (0 and 12 months). The parameters evaluated in the breast and in the thigh were: final pH, color (L* - luminosity, a* - red index, b* - yellow index, C* - saturation index and h* - tonality angle), weight loss per cooking (WLC), shear force (SF) and lipid stability. In addition, we evaluated the proportion of chemical forms of myoglobin of the thigh and the quantification of selenium content in the breast. There was no isolated effect of diet on the physical and chemical parameters of the breast and thigh and selenium concentration in the breast. Females had higher mean values of L* (57.57), b* (10.55) and C* (10.60) of the breast; and males of L* (55.09) of the thigh. Among males, poultry fed with the control diet and chromium showed higher SF values of the thigh than those supplemented with selenium; for the treatment with chromium, the males presented superior average of SF of the thigh and, in contrast, for the treatment with selenium, the females had the highest average. Samples submitted to the period of 12-month of storage showed higher values of substances reactive to thiobarbituric acid (TBARS) in both cuts. Supplementation with biocomplexed chromium and selenium did not cause changes in meat quality; females presented better attributes of meat quality.(AU)

Efeitos do congelamento prévio à maturação na aceitação sensorial da cor da carne bovina / Effects of freezing/thawing and aging on sensorial beef color

Objetivou-se avaliar o efeito do congelamento prévio a maturação (0 e 14 dias) sobre a aceitação sensorial da cor da carne bovina, comparando com amostras não-congeladas. O congelamento reduziu os valores de pH das amostras (de 5,58 para 5,48) e aumentou a proporção de oximioglobina (de 69 para 73%) nas amostras não-maturadas. Todos os índices de cor foram afetados pelo tempo de maturação, ficando mais claras (maior L*), com tonalidade vermelha mais alaranjada (maior h) e mais intensa (maior C*). O congelamento reduziu os valores de L*, sendo que as amostras congeladas e maturadas por 14 dias foram percebidas como mais claras e reduziu a intenção de compra dos avaliadores. Conclui-se que o congelamento tem pouco efeito sob a coloração da carne, mas a maturação subsequente reduziu a sua aceitação.

Acute responses of high-intensity circuit training in women: Low physical fitness levels show higher muscle damage / Respostas agudas de um circuito de treino de alta intensidade em mulheres: Níveis baixos de aptidão física apresentam maior dano muscular

High-intensity intermittent exercise (HIIE) elicits large improvements in health and cardiorespiratory fitness (CRF). HIIE can be applied with calisthenics exercises to improve strength and endurance. The acute effects of high-intensity circuit training (HICT) considering different CRF on myological variables are unknown. The aim was measure acute effects of HICT in young women considering different levels of CRF. Twelve women were allocated in two groups, who achieve 41mLO2•kg-1•min-1 or more= High Physical Fitness (HPF, n=5) and who achieve less than 41mLO2•kg-1•min-1= Low Physical Fitness (LPF,n=7). Protocol: 2x4 sets of 20 seconds at maximum intensity (all-out fashion) interspersed with 10 seconds of passive rest (jumping jacks, squat and thrust using 2kg dumbbells, mountain climber, and burpees). Blood samples were collected before, immediately after, 15minutes, 30minutes, one hour and 24 hours after. Heart rate, serum myoglobin, lactate, and creatine kinase (CK) concentration were analyzed. The HR achieved 94.1±3.7% of HRmax for LPF and 104.5±20.3% for HPF, p=0.03. The mean of delta lactate was similar between groups. The highest myoglobin has reached at 1h after the exercise protocol, with 50.0±30.2 ng/mL for LPF and 36.9±9.25 ng/mL for HPF. The delta of total CK before and after the exercise protocol shows that the serum CK level in LPF was significantly higher than HPF group (p=0.042). HICT composed by calisthenic protocol produced elevated and similar effects on HRmax, serum lactate and myoglobin in the woman with HPF and LPF. However, LPF group presented higher muscle damage inferred by serum CK concentrations.

O exercício intermitente de alta intensidade(HIIE) melhora a saúde e a aptidão cardiorrespiratória(CRF). HIIE pode ser aplicado com exercícios calistênicos para melhorar a força e resistência. Os efeitos agudos do treinamento de alta intensidade(HICT) considerando diferentes CRF em variáveis miológicas são desconhecidos. O objetivo foi medir os efeitos agudos do HICT em mulheres jovens, considerando diferentes níveis de CRF. Elas foram alocadas pelo nível de VO2máx. em dois grupos, as que atingiram 41mLO2•kg-1•min-1 ou mais= alta aptidão física(HPF,n=5) e menos de 41mLO2•kg-1•min-1= baixo aptidão física(LPF,n=7). Protocolo: 2x4 séries de 20s com intensidade máxima (all-out) intercalados com 10s de repouso passivo (jumping jacks, squat and thrust usando halteres 2kg, mountain climber e burpees). Sangue foi coletado antes, zero, 15, 30min, 1h e 24hs depois. Foram analisadas, freqüência cardíaca, mioglobina sérica, lactato e creatina quinase (CK). A FC alcançou 94,1±3,7% da FCmax para LPF e 104,5±20,3% para HPF, p=0,03. A média do delta lactato foi semelhante entre os grupos. O pico de mioglobina foi 1h após o protocolo de exercício, com 50.0±30.2ng/mL para LPF e 36.9±9.25ng/mL para HPF. O delta de CK total antes e depois do protocolo de exercício mostra que o nível sérico de CK no LPF foi significativamente maior do que o grupo HPF(p=0,042). O HICT com exercícios calistênicos produziu efeitos elevados e semelhantes sobre FCmax, lactato sérico e mioglobina nas mulheres com alta e baixa aptidão física. No entanto, o grupo LPF apresentou maior dano muscular inferido pelas concentrações séricas de CK.

Interleukin-6 contributes to myocardial damage in pregnant rats with reduced uterine perfusion pressure

Preeclampsia is one of the most frequent and difficult illnesses in pregnancy, which jeopardizes both mother and fetus. There are several diagnostic criteria for preeclampsia. However, the preeclampsia-associated myocardial damage has not been described. In this study, we employed reduced uterine perfusion pressure (RUPP) to generate a rat model of preeclampsia for the evaluation of myocardial damage in late-gestation rats. The expressions of cardiac injury markers were analyzed by immunohistochemistry and ELISA. The arterial pressure and myocardial tissue velocities were also measured. The role of interleukin (IL)-6 in RUPP-associated myocardial damage was further explored. The results showed that RUPP rats had significant myocardial damage, as demonstrated by the high expressions of myoglobin, creatine kinase isoenzyme, cardiac troponin I, and brain natriuretic peptide. In addition, RUPP increased the mean arterial pressure and the early transmitral flow velocity to mitral annulus early diastolic velocity ratio (E/Ea). Furthermore, IL-6 deteriorated these abnormalities, whereas inhibition of IL-6 significantly relieved them. In conclusion, our study demonstrated that RUPP rats displayed myocardial damage in an IL-6-dependent manner.

Changes in serum cardiac myosin light chain 1 levels in children with fulminant myocarditis during continuous blood purification

Summary Objective: To investigate the changes in serum cardiac myosin light chain 1 (CMLC-1) levels in children with fulminant myocarditis (FM) during continuous blood purification (CBP), as well as to analyze its correlation with other laboratory indexes. Method: Twenty-four (24) children with FM who underwent CBP were enrolled. Before and during treatment (48 and 72 hours after treatment, or death), the optical density value of serum CMLC-1 was measured using enzyme-linked immunosorbent assay, and then the serum CMLC-1 concentration was calculated. The correlations between CMLC-1 OD value change and laboratory indexes including creatine kinase-MB (CK-MB), troponin, myohemoglobin and N-terminal pro-brain natriuretic peptide (NT-proBNP) were analyzed. Results: The serum CMLC-1 concentration significantly increased in the children with FM and decreased obviously during CBP therapy. In the same period, the change of CMLC-1 concentration were positively correlated with creatine kinase-MB (r=0.528), troponin (r=0.726), myohemoglobin (r=0.702), and NT-proBNP levels (r=0.589). Conclusion: The serum CMLC-1 concentration increases significantly in children with FM, but CBP therapy can effectively control this increase.

Sinovite e tenossinovite no Brasil: uma análise dos benefícios auxílio-doença / Synovitis and tenosynovitis in Brazil: analysis of sickness benefit claims

OBJETIVO: Analisar os fatores pessoais associados à prevalência e duração dos benefícios auxílio-doença decorrentes de sinovite e tenossinovite (CID10 M65). MÉTODO: Estudo transversal referente aos benefícios auxílio-doença decorrentes de sinovite e tenossinovite concedidos pelo Instituto Nacional de Seguro Social aos empregados no Brasil em 2008. Dados sobre o ramo de atividade econômica (Classificação Nacional de Atividades Econômicas - CNAE divisão, classe), sexo, idade, espécie e duração dos benefícios foram coletados do Sistema Único de Benefícios. A população corresponde à média mensal dos vínculos empregatícios declarados ao Cadastro Nacional de Informações Sociais. RESULTADOS: Em 2008 foram concedidos 35.601 benefícios auxílio-doença decorrentes de sinovite e tenossinovite, com prevalência de 10,9/10.000 vínculos empregatícios. No conjunto dos benefícios auxílio-doença houve maior razão de prevalência (RP) acidentária (RP 1,2), sendo esta maior em mulheres (RP 3,3), e em trabalhadores com idade acima de 39 anos (RP 1,4). As CNAE 37-Esgoto (55,4) e 60-Atividade de rádio e TV (47,1) apresentaram as maiores prevalências, no entanto, 64-Atividade de serviços financeiros e 6422-Bancos múltiplos caracterizaram mais acidentes de trabalho (RP 3,2 e 3,8, respectivamente) e maior duração (70 e 73 dias, respectivamente). A maior duração de benefício ocorreu entre trabalhadores com idade superior a 39 anos. Tanto a CNAE-divisão 60-Atividade de rádio e TV, quanto a CNAE-classe 6010-Atividade de rádio apresentaram elevadas razões de feminilidade (RP 8,1 e 10,8, respectivamente). CONCLUSÃO: A incapacidade para o trabalho por sinovite e tenossinovite apresenta associação tanto da prevalência quanto da duração com o ramo de atividade, sexo, idade e espécie de benefício (previdenciário/acidentário). .

OBJECTIVE: To analyse the personal and occupational factors associated with the prevalence and duration of sickness benefit claims due to synovitis and tenosynovitis (CID10 M65). METHODS: Cross-sectional study regarding sickness benefit claims due to synovitis and tenosynovitis granted to employees by National Institute of Social Security in Brazil in 2008. Data on economic activity (Economic Activities National Classification - CNAE division, class), sex, age, type and duration of benefits were collected from the Unified Benefit System. The study's population consists of the average monthly employment contracts declared to the National Register of Social Information. RESULTS: In 2008, 35,601 employees were granted sickness benefits due to synovitis and tenosynovitis, with a prevalence of 10.9/10,000 employments. Sickness benefits showed higher prevalence rates (PR) for work-related claims (PR 1,2), mostly made by females (PR 3.3) and by workers older than 39 years (PR 1,4). The CNAE 37-Sewage (55.4) and 60-Broadcasting Activity (47.1) had the highest overall prevalence. However, the 64-Financial service activities, except insurance and pension funding and 6422-Multiple banks with commercial service had the highest rates of work-related claims (RP 3.2 and 3.8, respectively), and the longer duration (70 and 73 days, respectively). Workers older than 39 years had the highest durations of work disability claims. Both the CNAE-division 60-Broadcasting Activity, and the CNAE-class 6010-Radio showed a high activity ratio of females (PR 8.1 and 10.8, respectively). CONCLUSION: The work disability due to synovitis and tenosynovitis presents prevalence and duration associated with economic activity, sex, age and kind of benefit (non work-related and work-related claims). .

Neonatal hyper- and hypothyroidism alter the myoglobin gene expression program in adulthood

Myoglobin acts as an oxygen store and a reactive oxygen species acceptor in muscles. We examined myoglobin mRNA in rat cardiac ventricle and skeletal muscles during the first 42 days of life and the impact of transient neonatal hypo- and hyperthyroidism on the myoglobin gene expression pattern. Cardiac ventricle and skeletal muscles of Wistar rats at 7-42 days of life were quickly removed, and myoglobin mRNA was determined by Northern blot analysis. Rats were treated with propylthiouracil (5-10 mg/100 g) and triiodothyronine (0.5-50 µg/100 g) for 5, 15, or 30 days after birth to induce hypo- and hyperthyroidism and euthanized either just after treatment or at 90 days. During postnatal (P) days 7-28, the ventricle myoglobin mRNA remained unchanged, but it gradually increased in skeletal muscle (12-fold). Triiodothyronine treatment, from days P0-P5, increased the skeletal muscle myoglobin mRNA 1.5- to 4.5-fold; a 2.5-fold increase was observed in ventricle muscle, but only when triiodothyronine treatment was extended to day P15. Conversely, hypothyroidism at P5 markedly decreased (60%) ventricular myoglobin mRNA. Moreover, transient hyperthyroidism in the neonatal period increased ventricle myoglobin mRNA (2-fold), and decreased heart rate (5%), fast muscle myoglobin mRNA (30%) and body weight (20%) in adulthood. Transient hypothyroidism in the neonatal period also permanently decreased fast muscle myoglobin mRNA (30%) and body weight (14%). These results indicated that changes in triiodothyronine supply in the neonatal period alter the myoglobin expression program in ventricle and skeletal muscle, leading to specific physiological repercussions and alterations in other parameters in adulthood.

Biochemical study of the effects of cilostazol in rats subjected to acute ischemia and reperfusion of hind limbs

PURPOSE: To investigate whether cilostazol has a protective effect on acute ischemia and reperfusion of hind limbs of rats through study of biochemical variables in blood and urine. METHODS: Forty six animals were randomized and divided into two groups. Group I received a solution of cilostazol (10 mg/Kg) and group II received saline solution 0.9% (SS) by orogastric tube after ligature of the abdominal aorta. After four hours of ischemia the animals were divided into four subgroups: group IA (Cilostazol): two hours of reperfusion. Group IIA (SS): two hours of reperfusion. Group IB (Cilostazol): six hours of reperfusion. Group IIB (SS) six hours of reperfusion. After the reperfusion period, was held to collect urine and blood for biochemical measurements. The biochemical parameters studied were: urea, creatinine, sodium, potassium and myoglobin in blood and urea, creatinine, myoglobin in urine. RESULTS: There was no statistically significant difference between groups. CONCLUSION: Cilostazol had no protective effect on ischemic acute reperfusion of hind limbs of rats in this model.

Substituição parcial de nitrito por antioxidantes e seu efeito sobre a cor de linguiça defumada / Partial replacement of nitrite by antioxidants and its effect on smoked sausage color

A coloração dos produtos cárneos, conferida pela mioglobina, é um fator importante para aceitabilidade do consumidor e indicativo de qualidade. Há associação entre a oxidação lipídica com esse pigmento e sua influência na coloração da carne, o que induz a realizar estudos sobre antioxidantes. Este trabalho investigou a ação da ficocianina, α-tocoferol e ácido ascórbico, em substituição parcial ao nitrito, na manutenção da cor da linguiça mista defumada. No preparo das linguiças foram utilizados seis tratamentos (0,005% nitrito de sódio + antioxidante) e um controle (0 A) contendo somente nitrito. Os tratamentos testados foram: 1 A e 1 B (ácido ascórbico), 2 A e 2 B (α-tocoferol), 3 A e 3 B (ficocianina). As linguiças foram defumadas durante oito horas a 65 ºC e armazenadas a 4 ºC e foram analisadas quanto a cor, pH e nitrito residual.O tratamento 2 B mostrou-se mais eficiente na manutenção da cor vermelha, pela ação doα-tocoferol. A incorporação do ácido ascórbico (tratamento 1 A) acelerou a redução da metamioglobinae a conversão do nitrito em óxido nítrico. A adição de ficocianina (tratamento 3 A) reduziu a intensidadede cor vermelha e aumentou a intensidade de coloração amarela e a luminosidade.

Substituição parcial de nitrito por antioxidantes e seu efeito sobre a cor de linguiça defumada / Partial replacement of nitrite by antioxidants and its effect on smoked sausage color

A coloração dos produtos cárneos, conferida pela mioglobina, é um fator importante para aceitabilidade do consumidor e indicativo de qualidade. Há associação entre a oxidação lipídica com esse pigmento e sua influência na coloração da carne, o que induz a realizar estudos sobre antioxidantes. Este trabalho investigou a ação da ficocianina, α-tocoferol e ácido ascórbico, em substituição parcial ao nitrito, na manutenção da cor da linguiça mista defumada. No preparo das linguiças foram utilizados seis tratamentos (0,005% nitrito de sódio + antioxidante) e um controle (0 A) contendo somente nitrito. Os tratamentos testados foram: 1 A e 1 B (ácido ascórbico), 2 A e 2 B (α-tocoferol), 3 A e 3 B (ficocianina). As linguiças foram defumadas durante oito horas a 65 ºC e armazenadas a 4 ºC e foram analisadas quanto a cor, pH e nitrito residual.O tratamento 2 B mostrou-se mais eficiente na manutenção da cor vermelha, pela ação doα-tocoferol. A incorporação do ácido ascórbico (tratamento 1 A) acelerou a redução da metamioglobinae a conversão do nitrito em óxido nítrico. A adição de ficocianina (tratamento 3 A) reduziu a intensidadede cor vermelha e aumentou a intensidade de coloração amarela e a luminosidade.

Effect of triiodothyronine on the maxilla and masseter muscles of the rat stomatognathic system

The maxilla and masseter muscles are components of the stomatognathic system involved in chewing, which is frequently affected by physical forces such as gravity, and by dental, orthodontic and orthopedic procedures. Thyroid hormones (TH) are known to regulate the expression of genes that control bone mass and the oxidative properties of muscles; however, little is known about the effects of TH on the stomatognathic system. This study investigated this issue by evaluating: i) osteoprotegerin (OPG) and osteopontine (OPN) mRNA expression in the maxilla and ii) myoglobin (Mb) mRNA and protein expression, as well as fiber composition of the masseter. Male Wistar rats (~250 g) were divided into thyroidectomized (Tx) and sham-operated (SO) groups (N = 24/group) treated with T3 or saline (0.9 percent) for 15 days. Thyroidectomy increased OPG (~40 percent) and OPN (~75 percent) mRNA expression, while T3 treatment reduced OPG (~40 percent) and OPN (~75 percent) in Tx, and both (~50 percent) in SO rats. Masseter Mb mRNA expression and fiber type composition remained unchanged, despite the induction of hypo- and hyperthyroidism. However, Mb content was decreased in Tx rats even after T3 treatment. Since OPG and OPN are key proteins involved in the osteoclastogenesis inhibition and bone mineralization, respectively, and that Mb functions as a muscle store of O2 allowing muscles to be more resistant to fatigue, the present data indicate that TH also interfere with maxilla remodeling and the oxidative properties of the masseter, influencing the function of the stomatognathic system, which may require attention during dental, orthodontic and orthopedic procedures in patients with thyroid diseases.

Mecanismo de oxidação aeróbica de acetoacetato e 2-metilacetoacetato catalisada por mioglobina: implicações em desordens cetogênicas / Mechanism of the aerobic oxidation of acetoacetate and 2- methylacetoacetate catalyzed by Mb: implications for ketogenic disorders

Acetoacetato (AA) e 2-metilacetoacetato (MAA) são compostos β-cetoácidos acumulados em diversas desordens metabólicas como no diabetes e na isoleucinemia, respectivamente. Examinamos o mecanismo de oxidação aeróbica de AA e MAA iniciada por intermediários reativos de mioglobina de coração de cavalo (Mb) gerados pela adição de H2O2. Uma rota quimioluminescente que envolve um intermediário dioxetânico cuja termólise gera espécies α-dicarbonílicas (metilglioxal e biacetilo) foi proposta e estudada. Emissão de luz ultra fraca acompanha a reação, e sua intensidade aumenta linearmente pelo aumento da concentração tanto de Mb (10-500 µM) quando AA (10-100 mM). Estudos de consumo de oxigênio mostraram que MAA é, como esperado, quase uma ordem de grandeza mais reativo que AA. Estudos de EPR com captação de spin, utilizando MNP, possibilitaram detectar adutos de MAA atribuíveis a um radical centrado no Cα (aN = 1.55 mT) e ao radical acetila (aN = 0.83 mT). O sinal do radical acetila é totalmente suprimido por sorbato, um conhecido e eficiente supressor de espécies tripletes, o que é consistente com uma rota reacional envolvendo um intermediário dioxetânico. Clivagem-α da ligação carbonila-carbonila do produto biacetilo triplete produziria, de fato, radicais acetila. Além disso, utilizando AA como substrato para Mb/H2O2, um sinal de EPR atribuível ao aduto MNP-AA• (aN = 1.46 mT e aH = 0.34 mT) foi observado e confirmado por efeito isotópico. O consumo de oxigênio e o rendimento de compostos α-dicarbonílicos foram dose-dependentes à concentração de AA ou MAA (1-50 mM) bem como à concentração de H2O2 adicionado às misturas de reação contendo Mb (até 1:10 quando medido o consumo de oxigênio, e até 1:25 quando medido o rendimento de compostos α-dicarbonílicos) e tert-butilhidroperóxido (até 1:200). Os perfis de pH (5,8-7,8) para consumo de oxigênio e rendimento de compostos α-dicarbonílicos mostraram maiores rendimentos para baixos valores de pH, indicativo de ferrilMb...

Acetoacetate (AA) and 2-methylacetoacetate (MAA) are β-ketoacids accumulated in several metabolic disorders such as diabetes and isoleucinemia, respectively. Here we examine the mechanism of AA and MAA aerobic oxidation initiated by the reactive enzyme intermediates formed by the reaction of muscle horse myoglobin (Mb) with H2O2. A chemiluminescent route involving a dioxetane intermediate whose thermolysis yields triplet α-dicarbonyl species (methylglyoxal and diacetyl) is envisaged. Accordingly, the ultraweak light emission that accompanies the reaction increases linearly by raising the concentration of both Mb (10-500 µM) and AA (10- 100 mM). Oxygen uptake studies revealed that MAA is, expectedly, almost one order of magnitude more reactive than AA. EPR spin-trapping studies with MNP detected spin adducts from MAA attributable to an α-carbon-centered radical (aN = 1.55 mT) and to an acetyl radical (aN = 0.83 mT). As the acetyl radical signal is totally suppressed by sorbate, a well-known efficient triplet species quencher, the dioxetane hypothesis seems to be reliable. The α-cleavage of the carbonyl-carbonyl bond of a putative excited triplet diacetyl product would, in fact, leads to an acetyl radical. Furthermore, using AA as substrate for Mb/H2O2, an EPR signal assignable to a MNP-AA• adduct (aN = 1.46 mT and aH = 0.34 mT) was observed and confirmed by isotope effect. Oxygen consumption and α-dicarbonyl yield were also dependent on AA or MAA concentrations (1-50 mM) as well as on the concentration of peroxide added to the Mb-containing reaction mixtures: H2O2 (up to 1:10 when measuring oxygen uptake and up to 1:25 when measuring the α-dicarbonyl yield) and t-butOOH (up to 1:200). The pH profiles (5.8-7.8) of oxygen consumption and α-dicarbonyl yield show higher reaction rates at lower pHs, indicative of a ferrylMb intermediate. Evaluating Mb lesion, both β-ketoacids reduced disorganization of the secondary and tertiary protein structure elicited by H2O2...

Revisão da participação dos marcadores séricos de necrose miocárdio no diagnóstico da síndrome coronariana aguda / Revision of the participation of the serum markers of necrosis myocardium in the diagnosis of the acute coronary syndrome

Esta revisão aborda a síndrome coronariana aguda e as mudanças que ocorreram ao longo dos anos com os marcadores séricos de necrose miocárdica. Novos marcadores apareceram e modificaram o critério para o diagnóstico e manejo dos pacientes com síndrome coronariana aguda.

Determinación cualitativa de marcadores de necrosis miocárdica desde la fase prehospitalaria del síndrome coronario agudo / Qualitative determination of markers for myocardiac necrosis during pre-hospital admission for acute coronary syndrome

Objetivo: medir el valor diagnóstico que tienen la troponina I, mioglobina y creatinfosfocinasa MB (CPK-MB) desde la fase de atención prehospitalaria, en pacientes con dolor torácico. Material y métodos: pacientes consecutivos que solicitaron atención prehospitalaria con ambulancia de terapia intensiva o que se encontraban en las primeras horas de hospitalización por dolor torácico. A todos se les realizó electrocardiograma de 12 derivaciones en la ambulancia o en el servicio de urgencias, y se les determinó nivel de creatinfosfocinasa sérica total (como patrón de referencia). Fueron distribuidos en cinco grupos: grupo I, 13 pacientes con infarto agudo del miocardio sin elevación del segmento ST; grupo II, 11 pacientes con angina inestable; grupo III, 14 pacientes con dolor torácico atípico para angina; grupo IV, cinco sujetos sanos; grupo V, cinco pacientes con infarto agudo del miocardio con elevación del segmento ST. Se hizo una evaluación cualitativa con un dispositivo automático de interpretación rápida para troponina I, mioglobina y CPK-MB. Resultados: 48 pacientes con edad promedio de 55 + 18 años: 25 hombres (52 %) y 23 mujeres (48 %). La mediana del tiempo de evolución de iniciados los síntomas fue de 3.5 horas (cuartiles 25, 75: 2 a 6). Para la troponina I, mioglobina y CPK-MB, la especificidad fue de 94, 91 y 94 %; la sensibilidad fue de 100 % para los tres marcadores, al igual que el valor predictivo negativo; el valor predictivo positivo fue de 89, 84 y 89 %, y el cociente de probabilidad de 8.7, 5.5 y 8.7, respectivamente. Conclusiones: desde la fase prehospitalaria, la troponina I, mioglobina y CPK-MB tienen alto valor diagnóstico en el síndrome coronario agudo. Su determinación es recomendable como parte del protocolo de diagnóstico y de gran ayuda para decidir la hospitalización y el tratamiento.

OBJECTIVE: We measured the diagnostic value of troponin I (TnI), mioglobin (Miog) and creatine kinase MB (CPK-MB) in patients with thoracic pain during the period of preadmission to the hospital. METHODS: We included patients who requested prehospital attention with intensive therapy ambulance or who were in the first hours of hospitalization for thoracic pain. A 12-lead electrocardiogram was carried out in the ambulance or in the emergency room. The levels of total creatine phosphokinase were determined (as reference pattern). Five study groups were included: group I, 13 patients with acute myocardial infarction without elevation of the ST segment; group II, 11 patients with unstable angina; group III, 14 patients with atypical thoracic pain for angina; group IV, five healthy patients; and group V, five patients with acute myocardial infarction with elevation of the ST segment. A qualitative evaluation was made with an automatic device for quick interpretation of TnI, Miog and CPK-MB. RESULTS: Forty eight patients were studied with an average age of 55+/-18 years, 25 men (52%) and 23 women (48%), average time of symptom evolution was 3.5 h (quartiles 2 and 6 h). Total level of CPK was taken as a reference pattern. Sensitivity of TnI, Miog, and CPK-MB was 100%, specificity was 94, 91 and 94%, respectively. Positive predictive value was 89, 84 and 89%, respectively. Negative predictive value was 100%. Likelihood of probability was 8.7, 5.5 and 8.7, respectively. CONCLUSIONS: TnI, Miog and CPK-MB have high diagnostic value in acute coronary syndrome (ACS) from the time of prehospital admission. Determination is advisable as part of the diagnostic protocol, which is of great importance in order to plan the hospitalization and treatment in this group of patients.

Cardioversão elétrica e lesão miocárdica: avaliação pelos novos marcadores de injúria cardíaca / Electrical cardioversion and myocardial injury: evaluation by new cardiac injury markers

OBJETIVO: Avaliar, através da evolução dos novos marcadores bioquímicos de injúria cardíaca, se a cardioversão elétrica (CVE) causa lesão miocárdica. MÉTODOS: Foram avaliados 76 pacientes (P) submetidos a CVE eletiva de fibrilação atrial ou flutter atrial. Medidas de creatinafosfoquinase (CPK), CKMB-atividade e dosagem de CKMB-massa (M), mioglobina e troponina I cardíaca (cTnI) foram determinadas antes e após 6 e 24 horas da CVE. RESULTADOS: A CVE resultou um sucesso em 58 P (76,3 por cento). A carga cumulativa (CC) foi de até 350 joules (J) em 36 P, de 500 a 650 J em 20 P e de 900 a 960 J em 20 P, com energia média aplicada de 493 J (± 309). A cTnI permaneceu dentro da normalidade nos 76 P. Com o aumento da CC, ocorreu elevação de CPK (> valor de p = 0,007), CKMB-atividade (> valor de p = 0,002), CKMB-M (> valor de p = 0,03) e mioglobina (> valor de p = 0,015). Correlação positiva foi observada entre a CC e picos de CPK (r = 0,660; p < 0,001), CKMB-atividade (r = 0,429; p < 0,0001), CKMB-M (r = 0,265; p = 0,02) e mioglobina (r = 0,684; p < 0,0001). Correlação também positiva ocorreu entre o número de choques e picos de CPK (r = 0,770; p < 0,001), CKMB-atividade (r = 0,642; p < 0,0001), CKMB-M (r = 0,430; p < 0,0001) e mioglobina (r = 0,745; p < 0,0001). CONCLUSÃO: A CVE não causa lesão miocárdica detectável pela dosagem da cTnI. Elevações de CPK, CKMB-atividade, CKMB-M e mioglobina são decorrentes de lesão do músculo esquelético, estando correlacionadas positivamente com a CC aplicada ou com o número de choques.

Propéptido natriurético tipo B N-terminal: un predictor de mal pronóstico en síndromes coronarios sin elevación del segmento ST / N-Terminal pro B type natriuretic peptide: a predictor of adverse outcome in coronary syndrome patients without ST segment elevation

Antecedentes: El péptido natriurético cerebral tipo B (BNP) es un fuerte predictor de mal pronóstico en síndromes coronarios agudos. El propéptido natriurético tipo BN terminal (NT pro-BNP)podría constituir un marcador útil para la estratificación de riesgo temprana en estas situaciones. Objetivos: Determinar la relación entre niveles de NT pro-BNP y la mortalidad a los 30 días en pacientes con síndromes coronarios agudos. Métodos: Se midieron los niveles de NT pro-BNP, troponina T, CK-MB masa, proteína C reactiva (PCR)y mioglobina (Mb) al ingreso y a las 12 horas en muestras de suero obtenidas en 254 pacientes incluídos en un estudio de cohorte prospectivo y multicéntrico de síndromes coronarios agudos sin elevación del ST. El punto final primario fue muerte a los 30 días. Resultados: La mortalidad global a los 30 días fue del 3,8 por ciento. Se determinaron los niveles de NT pro-BNP en muestras obtenidas a una mediana 4,9 horas (ingreso hospitalario) y una segunda a una mediana de 12 horas del inicio de los síntomas. Las concentraciones de NT pro-BNP en los sobrevivientes (392,5 pg/ml) fue significativamente menor que en aquellos fallecidos(2.706 pg/ml), p = 0,003. El análisis por un modelo de regresión logística que incluyó predictores significativos (desniveles del ST y marcadores elevados) mostró que tanto los niveles de pro-BNP al ingreso (OR 5 [IC 95 por ciento 1-24,9] p = 0,04), como a las 12 horas (OR 3,4 [IC 95 por ciento 1,1-9,7] p = 0,02) fueron predictores independientes de mortalidad a los 30 días. Conclusión: El pro-BNP N terminal es un predictor precoz e independiente de mortalidad a corto plazo en los síndromes coronarios agudos sin elevación del segmento ST.