Erythrocyte oxidative stress markers in children with sickle cell disease / Marcadores de estresse oxidativo em eritrócitos de crianças com doença falciforme

Abstract Objective To determine eight parameters of oxidative stress markers in erythrocytes from children with sickle cell disease and compare with the same parameters in erythrocytes from healthy children, since oxidative stress plays an important role in the pathophysiology of sickle cell disease and because this disease is a serious public health problem in many countries. Methods Blood samples were obtained from 45 children with sickle cell disease (21 males and 24 females with a mean age of 9 years; range: 3–13 years) and 280 blood samples were obtained from children without hemoglobinopathies (137 males and 143 females with a mean age of 10 years; range: 8–11 years), as a control group. All blood samples were analyzed for methemoglobin, reduced glutathione, thiobarbituric acid reactive substances, percentage of hemolysis, reactive oxygen species, and activity of the enzymes glucose 6-phosphate dehydrogenase, superoxide dismutase, and catalase. Data were analyzed using Student's t-test and were expressed as the mean ± standard deviation. A p-value of <0.05 was considered significant. Results Significant differences were observed between children with sickle cell disease and the control group for the parameters methemoglobin, thiobarbituric acid reactive substances, hemolysis, glucose 6-phosphate dehydrogenase activity, and reactive oxygen species, with higher levels in the patients than in the controls. Conclusions Oxidative stress parameters in children's erythrocytes were determined using simple laboratory methods with small volumes of blood; these biomarkers can be useful to evaluate disease progression and outcomes in patients.

Resumo Objetivo Determinar parâmetros de estresse oxidativo em eritrócitos de crianças com doença falciforme e compará-los com os mesmos parâmetros em eritrócitos de crianças saudáveis, pois o estresse oxidativo desempenha um importante papel na fisiopatologia da doença falciforme, considerada um sério problema de saúde pública em muitos países. Métodos Foram obtidas amostras de sangue de 45 crianças com doença falciforme (21 meninos e 24 meninas com média de 9 anos, variação de 3 a 13) e 280 amostras de sangue de crianças sem hemoglobinopatias (137 meninos e 143 meninas com média de 10 anos, variação de 8 a 11), como grupo controle. Em todas as amostras foram determinados meta-hemoglobina, glutationa reduzida, substâncias reativas ao ácido tiobarbitúrico, porcentagem de hemólise, espécies reativas de oxigênio e atividade das enzimas glucose6-fosfato desidrogenase, superóxido dismutase e catalase. Os dados foram analisados com o teste t de Student e foram expressos como média ± desvio padrão. Um valor de p < 0,05 foi considerado significativo. Resultados Foram observadas diferenças significativas entre as crianças com doença falciforme e o grupo controle para os parâmetros meta-hemoglobina, substâncias reativas ao ácido tiobarbitúrico, porcentagem de hemólise, espécies reativas de oxigênio e atividade da enzima glucose6-fosfato desidrogenase, com níveis aumentados nos pacientes. Conclusões Foi possível determinar parâmetros de estresse oxidativo em eritrócitos de crianças, com técnicas laboratoriais simples e pequenos volumes de sangue. Esses biomarcadores podem ser úteis na avaliação da progressão e dos resultados de tratamentos da doença.

Validação in vitro e in vivo da viabilidade de eritrócitos suínos estocados para estabelecer um modelo experimental de transfusão homóloga de hemácias: estudo piloto / In vitro and in vivo validation of stored swine erythrocyte viability to establish an experimental model of homologous red blood cell transfusion: a pilot study

Objetivo: Para desenvolver modelos experimentais de transfusão de hemácias, o primeiro passo é assegurar a viabilidade dos eritrócitos transfundidos. Avaliamos a viabilidade de eritrócitos transfundidos com validação in vitro e in vivo de eritrócitos suínos homólogos armazenados por 14 dias. Métodos: Neste estudo piloto, o sangue coletado de um suíno Agroceres® foi estocado em duas unidades de hemácias. A validação in vivo foi realizada pela marcação dos eritrócitos com Na2 51CrO4 e recuperação dos eritrócitos viáveis após 24 horas da infusão em um animal autólogo e quatro homólogos. A validação in vitro foi realizada na avaliação basal e após 14 dias, pela mensuração da hemoglobina, hematócrito, índice de hemólise e hemoglobina livre em seis unidades de hemácias. Foi realizada uma esplenectomia post-mortem para avaliar o sequestro esplênico de eritrócitos, e a radioatividade das amostras de sobrenadante foi contada para avaliar a hemólise intravascular. Resultados: Após 14 dias de estocagem, as unidades de hemácias tinham volumes menores e concentração total de hemoglobina equivalente em comparação aos padrões humanos. A concentração de hemoglobina livre aumentou de 31,0±9,3 para 112,4±31,4mg/dL (p<0,001) e o índice de hemólise aumentou de 0,1±0,1 para 0,5±0,1% (p<0,001). Entretanto, esses testes se encontravam dentro da faixa aceitável para os padrões humanos. A percentagem de radioatividade nas amostras de sobrenadante foi similar na avaliação basal e após 24 horas, afastando, assim, a presença de hemólise significante. Não se encontraram evidências de sequestro esplênico de eritrócitos radioativos. ...

Objective: To develop experimental models of erythrocyte transfusion, the first step is to ensure the viability of the red blood cells transfused. In this pilot study, we assessed the viability of transfused red blood cells with validation in vitro and in vivo of homologous swine erythrocytes stored for 14 days. Methods: Blood collected from one Agroceres® swine was stored in two red blood cell units. In vivo validation was performed by labeling the red blood cells with Na2 51CrO4 and recovering the viable erythrocytes after 24 hours of infusion in one autologous and four homologous animals. In vitro validation was performed at baseline and after 14 days in sixteen red blood cell units by measuring hemoglobin, hematocrit, hemolysis index and free hemoglobin. A post-mortem splenectomy was performed to evaluate the splenic sequestration of erythrocytes, and the radioactivity of the supernatant samples was counted to evaluate intravascular hemolysis. Results: After 14 days of storage, the red blood cell units had lower volumes and equivalent total concentrations of hemoglobin and hematocrit compared to human standards. The free hemoglobin concentration increased from 31.0±9.3 to 112.4±31.4mg/dL (p<0.001), and the hemolysis index increased from 0.1±0.1 to 0.5±0.1% (p<0.001). However, these tests were within the acceptable range for human standards. The percentage of radioactivity in supernatant samples was similar at baseline and after 24 hours, thus excluding significant hemolysis. No evidence of splenic sequestration of radioactive erythrocytes was found. Conclusion: Swine red blood cells stored for 14 days are viable and can be used in experimental studies of transfusion. These validation experiments are important to aid investigators in establishing experimental models of transfusion. .

Characteristics of hemolytic activity induced by skin secretions of the frog Kaloula pulchra hainana

The hemolytic activity of skin secretions obtained by stimulating the frog Kaloula pulchra hainana with diethyl ether was tested using human, cattle, rabbit, and chicken erythrocytes. The skin secretions had a significant concentration-dependent hemolytic effect on erythrocytes. The hemolytic activity of the skin secretions was studied in the presence of osmotic protectants (polyethylene glycols and carbohydrates), cations (Mg2+, Ca2+, Ba2+, Cu2+, and K+), or antioxidants (ascorbic acid, reduced glutathione, and cysteine). Results Depending on their molecular mass, osmotic protectants effectively inhibited hemolysis. The inhibition of skin hemolysis was observed after treatment with polyethylene glycols (1000, 3400, and 6000 Da). Among divalent cations, only 1 mM Cu2+ markedly inhibited hemolytic activity. Antioxidant compounds slightly reduced the hemolytic activity. Conclusions The results suggested that skin secretions of K. pulchra hainana induce a pore-forming mechanism to form pores with a diameter of 1.36-2.0 nm rather than causing oxidative damage to the erythrocyte membrane.

Characteristics of hemolytic activity induced by skin secretions of the frog Kaloula pulchra hainana

Background: Previous works had shown that scorpion venom induced neurotransmitter elevation and an inflammatory response associated with various anatomo-pathological modifications. The most dangerous scorpions species in Algeria responsible for these effects are Androctonus australis hector (Aah) and Androctonus amoreuxi (Aam). Results: Comparison of the physiopathological effects induced by the two venoms showed differences in the kinetic of cytokine release and in lung injury. The lung edema was only observed in response to Aah venom and it was correlated with cell infiltration. In order to better understand the involved mechanism in inflammatory response, we used two antagonists, atropine (non-selective muscarinic antagonist) and propranolol (ß adrenergic antagonist), which lead to a decrease of cell infiltration but has no effect on edema forming. Conclusion: These results suggest another pathway in the development of lung injury following envenomation with Aam or Aah venom.(AU)

Ecocardiografia de pacientes talassêmicos sem insuficiência cardíaca em tratamento com transfusões sanguíneas e quelação / Echocardiography in thalassemic patients on blood transfusions and chelation without heart failure

FUNDAMENTO: Pacientes com talassemia major (TM) apresentam hemólise crônica e necessitam de transfusões sanguíneas egularmente que podem causar cardiomiopatia por sobrecarga de ferro e insuficiência cardíaca crônica. A hemocromatose é caracterizada por acúmulo excessivo de ferro nos tecidos; acometimento do coração é a principal causa de óbito em pacientes com talassemia. OBJETIVO: Avaliar as estruturas e a função cardíaca por meio de ecocardiografia com Doppler convencional e Doppler tecidual em pacientes com TM, sem evidência clínica de insuficiência cardíaca. MÉTODOS: Trata-se de estudo observacional prospectivo de 18 pacientes com TM que recebem transfusão sanguínea regularmente. Para avaliar, separadamente, os efeitos da anemia e da transfusão sanguínea, dois grupos controles pareados por gênero, idade, peso e altura foram incluídos: um com indivíduos saudáveis (Saudável, n = 18) e outro com pacientes com anemia por deficiência de ferro (Anemia, n = 18). Análise estatística foi realizada utilizando ANOVA seguida pelo teste de Tukey ou Kruskal-Wallis e teste de Dunn. RESULTADOS: As seguintes variáveis ecocardiográficas apresentaram valores significativamente mais elevados no grupo TM do que nos grupos Anemia e Saudável: índice de volume do átrio esquerdo (Saudável: 16,4 ± 6,08; Anemia: 17,9 ± 7,02; TM: 24,1 ± 8,30 cm/m); razão E/Em septal mitral (Saudável: 6,55 ± 1,60; Anemia: 6,74 ± 0,74; TM: 8,10 ± 1,31) e duração do fluxo reverso em veias pulmonares [Saudável: 74,0 (59,0-74,0); Anemia: 70,5 (67,0-74,0); TM: 111 (87,0-120) ms]. Arazão E/A mitral foi maior no grupo TM do que no grupo Anemia (Saudável: 1,80 ± 0,40; Anemia: 1,80 ± 0,24; TM: 2,03 ± 0,34). Não foram encontradas diferenças entre os grupos em variáveis estruturais do ventrículo esquerdo e em índices de função sistólica. CONCLUSÃO: A ecocardiografia com Doppler convencional e o Doppler tecidual permite que alterações na função diastólica do ventrículo esquerdo sejam identificadas em pacientes assintomáticos com talassemia major.

BACKGROUND: Patients with thalassemia major present chronic hemolysis and require regular blood transfusions which may cause iron overload cardiomyopathy and chronic heart failure. Hemochromatosis is characterized by excessive iron accumulation in tissues, and heart involvement is the main cause of death in patients with thalassemia. OBJECTIVE: The aim of this study was to evaluate cardiac structure and function by conventional Doppler echocardiography and tissue Doppler imaging in patients with TM and no clinical evidence of heart failure. METHODS: This is a prospective observational study including 18 patients with thalassemia major (TM) receiving regular blood transfusion. To separately evaluate anemia and blood transfusion effects, two gender, age, weight, and height-matched control groups were included: one with healthy individuals (Healthy, n=18) and one with iron deficient anemia patients (Anemia, n=18). Statistical analysis was performed using ANOVA followed by Tukey's test or Kruskal-Wallis's and Dunn's test. RESULTS: The following echocardiographic variables presented significantly higher values in TM than the Anemia and Healthy groups: left atrium volume index (Healthy: 16.4±6.08; Anemia: 17.9±7.02; TM: 24.1±8.30 cm³/m²); mitral septal E/Em ratio (Healthy: 6.55±1.60; Anemia: 6.74±0.74; TM: 8.10±1.31); and duration of reverse pulmonary vein flow [Healthy: 74.0 (59.0-74.0); Anemia: 70.5 (67.0-74.0); TM: 111 (87.0-120) ms]. The mitral E/A ratio was higher in TM than Anemia (Healthy: 1.80±0.40; Anemia: 1.80±0.24; TM: 2.03±0.34). No differences were found in left ventricular structures and systolic function indexes. CONCLUSION: Conventional Doppler echocardiography and tissue Doppler allow changes in left ventricular diastolic function to be identified in asymptomatic patients with thalassemia major.

Hemólise na circulação extracorpórea: correlação com tempo e procedimentos realizados / Hemolysis in extracorporeal circulation: relationship between time and procedures

INTRODUÇÃO: A circulação extracorpórea (CEC) é indispensável para a maioria das operações cardíacas, mas causa danos significantes ao sangue, dentre eles a hemólise. OBJETIVO: Quantificar as taxas de hemólise em diferentes tempos nas operações para revascularização do miocárdio com uso de CEC. MÉTODOS: Foram medidas as taxas de hemólise de 22 pacientes em 6 tempos distintos durante a revascularização do miocárdio com uso de CEC: T0 - antes do início da CEC, T1 - 5 minutos após o início da CEC, T2 - com 30 minutos de CEC, T3 - imediatamente antes do despinçamento da aorta, T4 - imediatamente antes da passagem do volume residual para o paciente e T5 - 5 minutos após o término da passagem do volume residual para o paciente. Foram calculadas as taxas de hemólise entre os intervalos de tempo: T0-T1; T1-T2; T2-T3; T3-T4 e T4-T5. RESULTADOS: Os primeiros 5 minutos após a CEC demonstraram maior taxa de hemólise (P = 0,0003) em comparação às outras taxas calculadas, representando 29% da hemólise total até T4 (imediatamente antes da passagem do volume residual para o paciente). CONCLUSÃO: Não foram observadas variações significantes nas taxas de hemólise durante a aspiração na raiz da aorta (P > 0,38) nem com o procedimento utilizado para a passagem do volume residual de sangue no circuito para os pacientes.

INTRODUCTION: Extracorporeal circulation (EC) is very important in cardiac surgery but causes significant damage to the blood, including hemolysis. OBJECTIVE: To quantify the rate of hemolysis at different times during EC in elective coronary artery bypass grafting. METHODS: We measured rates of hemolysis of 22 patients at 6 different times during myocardial revascularization during EC: T0 - before the start of EC, T1 - five minutes after of the EC initiation, T2 - 30 minutes of EC, T3 - immediately before the aortic unclamping, T4 - immediately before passage of the residual volume to the patient and T5 - five minutes after the passage of the residual volume to the patient. Rates of hemolysis were calculated between the intervals of time: T0-T1; T1-T2; T2-T3; T3-T4 and T4-T5. RESULTS: The first 5 minutes after the EC showed the highest rate of hemolysis (P = 0.0003) compared to the others calculated rates, representing 29% of the total haemolysis until T4 (Immediately before passage of the residual volume to the patient). CONCLUSION: There were no significant changes in the rate of hemolysis during the suction in the aortic root (P> 0.38), nor with the procedure used for the passage of the residual volume of blood in the circuit to the patient.

The role of C-terminus carbohydrate-binding domain of Vibrio cholerae haemolysin/cytolysin in the conversion of the pre-pore β-barrel oligomer to a functional diffusion channel.

Background & objectives: Vibrio cholerae cytolysin/hemolysin (VCC) is a 65 kDa pore-forming toxin (PFT) secreted by O1 El Tor and non-O1 strains. The purified toxin, which contains two C-terminus carbohydrate-binding domains in addition to the cytolytic domain at the core, causes lysis of a wide spectrum of eukaryotic cells at picomolar concentrations, apoptogenesis of intestinal and immune cells and accumulation of fluid in rabbit ligated ileal loop. Therefore, it may potentially complement the action of cholera toxin (CT) in diarrheagenic strains that do not produce CT. We showed earlier that β1-galactosyl-terminated glycoconjugates are strong inhibitors of its pore-forming activity, though carbohydrates are not functional receptors of VCC. Here, we investigate how the 15 kDa C-terminus β-prism lectin domain contributed to pore formation in erthrocytes. Methods: VCC was isolated from the culture supernatant of late log phase grown bacteria and purified to homogeneity by chromatography. The 50 kDa truncated variant was generated by restricted proteolysis. Liposome was prepared by sonication of a suspension of phospholipids and calceine release assay was done by spectrofluorometric monitoring of the released dye trapped in liposome. Formation of β-barrel oligomers in erythrocyte stroma was monitored by scanning electron microscopy. Results: Proteolytic truncation of the C-terminus β-prism lectin domain decreased hemolytic activity of the toxin by ~800-fold without causing a significant change in pore-forming activity toward synthetic lipid vesicles devoid of incorporated glycoproteins/glycolipids. Truncation at the C-terminus did not impair membrane-binding or assembly to the oligomeric pore. Interpretation & conclusions: Our data indicated that the C-terminus domain played a critical role in translocation of the pre-pore oligomeric assembly from the cell surface or lipid-water interface to the hydrocarbon core of the membrane bilayer, signaling the formation of functional diffusion channels.

Low bone mass density is associated with hemolysis in brazilian patients with sickle cell disease

OBJECTIVES: To determine whether kidney disease and hemolysis are associated with bone mass density in a population of adult Brazilian patients with sickle cell disease. INTRODUCTION: Bone involvement is a frequent clinical manifestation of sickle cell disease, and it has multiple causes; however, there are few consistent clinical associations between bone involvement and sickle cell disease. METHODS: Patients over 20 years of age with sickle cell disease who were regularly followed at the Hematology and Hemotherapy Center of Campinas, Brazil, were sorted into three groups, including those with normal bone mass density, those with osteopenia, and those with osteoporosis, according to the World Health Organization criteria. The clinical data of the patients were compared using statistical analyses. RESULTS: In total, 65 patients were included in this study: 12 (18.5 percent) with normal bone mass density, 37 (57 percent) with osteopenia and 16 (24.5 percent) with osteoporosis. Overall, 53 patients (81.5 percent) had bone mass densities below normal standards. Osteopenia and osteoporosis patients had increased lactate dehydrogenase levels and reticulocyte counts compared to patients with normal bone mass density (p<0.05). Osteoporosis patients also had decreased hemoglobin levels (p<0.05). Hemolysis was significantly increased in patients with osteoporosis compared with patients with osteopenia, as indicated by increased lactate dehydrogenase levels and reticulocyte counts as well as decreased hemoglobin levels. Osteoporosis patients were older, with lower glomerular filtration rates than patients with osteopenia. There was no significant difference between the groups with regard to gender, body mass index, serum creatinine levels, estimated creatinine clearance, or microalbuminuria. CONCLUSION: A high prevalence of reduced bone mass density that was associated with hemolysis was found in this population, as indicated by the high lactate dehydrogenase levels, increased reticulocyte counts and low hemoglobin levels.

Análisis de algunas variables hematológicas, bioquímicas y clínicas en la anemia drepanocítica. Resultados preliminares / Analysis of some hematological, biochemical and clinical variables in cases of sickle cell anemia. Preliminary results

Se estudiaron 59 pacientes mayores de 18 años con anemia drepanocítica distribuidos en: grupo 1 (23) sin síndrome torácico agudo (STA), priapismo, ni úlceras maleolares; grupo 2 (39) que han presentado alguna de las complicaciones anteriores. En el grupo 2 se observó disminución significativa de la hemoglobina (Hb) y la Hb fetal, asícomo aumento de plaquetas, deshidrogenasa láctica (LDH), aspartato aminotransferasa (AST), alanino aminotransferasa (ALT), bilirrubina total (BT), directa (BD) e indirecta (BI), fosfatasa alcalina (FAL), creatin kinasa-MB (CK-MB) y de la frecuencia de accidente vascular encefálico. La frecuencia de STA, úlceras maleolares y priapismo en el grupo 2, fue del 83,3; 33,3 y 50 por ciento, respectivamente. El análisis de regresión lineal múltiple en el total de enfermos tomando como variable dependiente la LDH, mostró correlación negativa significativa para la Hb y el Hto y positiva para creatinina, AST, ALT, BT, BD, BI, FAL y CK-MB. La frecuencia de hipertensión pulmonar fue del 18,2 por ciento (n= 10). Estos estudios pueden ser útiles en el diagnóstico precoz de complicaciones relacionadas con la hemólisis

A total of 59 patients aged over 18 with sickle cell anemia were studied distributed in: group 1 (23) without acute thoracic syndrome (ACS), priapism and malleolus ulcers; group 2 (39) with some of above complications. In group 2 there was a significant decrease of hemoglobin (Hb) and the fetal Hb and a platelet increase, lactic dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TB), alkaline phosphatase (APH), creatine kinase-MB (ck-MB) and of encephalic stroke frequency. The frequency of AST, malleolus ulcers and priapism in group 2 was of 83.3 percent, 33.3 percent and 50 percent, respectively. The multiple linear regression analysis in all patients considering the LDH as a negati ve correlation significant for Hb and the Hto and positive for creatinine, AST, ALT, TB, DB, IB, APH and CK-MB. The pulmonary hypertension frequency was of 18.2 percent (n= 10). These studies may be useful in the early diagnosis of hemolysis-related complications

Septicemia fatal causada por Vibrio cholerae no-O1, no-O139 hemolítico en Chile: Caso clínico / Non-toxigenic hemolytic Vibrio cholerae non-O1non-O139 fatal septicemia: Report of one case

We report a 70-year-old woman, who had recently consumed shellfish, that was admitted to the intensive care unit with septic shock and died 19 hours later due to a multi-organic failure. Microbiological, serological and molecular assays confirmed a hemolytic tdh+ Vibrio cholerae non-01, non 0139 as the etiologic agent (Rev Méd Chile 2009; 137: 1193-6).

Hematological parameters in sick cell anemia patients with and without priapism

Priapism was associated with certain hematological parameters in sickle cell anemia [SCA] patients in one report but not in another. We studied differences in haematological parameters between SCA patients with and without priapism. Eighteen patients with SCA who presented with acute priapism during the years 2001-2004 were compared with age- and sex-matched SCA patients without priapism with respect to hematocrit, reticulocyte count, level of irreversibly sickled cells [ISC], percentage of haemoglobin F [Hb F], total leukocyte and platelet counts. SCA patients with priapism had a mean hematocrit of 0.28 L/L which was significantly higher than the mean hematocrit value of 0.24 L/L [P<0.05] in patients without priapism. The mean reticulocyte count of 8% in patients with priapism was significantly lower than mean reticulocyte count of 12% [P<0.05] in patients without priapism. The level of ISC of 3% in patients with priapism was significantly lower than the level of 6.5% [P<0.05] in patients without priapism. There was no statistically significant difference in the mean levels of Hb F [7% vs. 6%]. Patients with priapism had a mean leukocyte count and mean platelet count that did not significantly differ from values in patients without priapism. SCA patients with priapism had a lower rate of hemolysis, resulting in a higher hematocrit and greater blood viscosity, which increased the risk of corpora cavernosal sickling and blockade. Hence, a relatively high hematocrit is a risk factor for the development priapism in patients with sickle cell anemia

Lipid peroxidation, hemolysis and antioxidant enzymes of erythrocytes in stroke.

Erythrocyte membrane lipid peroxidation and consequent percentage hemolysis and related antioxidant enzymes viz., superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase were determined in 16 cases of hemorrhagic stroke and 30 cases of thrombotic stroke. The results obtained were compared with 50 age and sex matched controls. 12 thrombotic stroke patients who showed symptomatic recovery after medication were considered for follow up. Lipid peroxidation and percentage hemolysis in patients with thrombotic stroke and hemorrhagic stroke was significantly elevated when compared to controls. Glutathione reductase and superoxide dismutase levels were found to be significantly reduced in thrombotic stroke and hemorrhagic stroke respectively, when compared to healthy subjects. There was no significant difference in the other parameters when compared to controls. In post treatment thrombotic stoke, catalase and glutathione reductase levels increased significantly and oxidative hemolysis decreased compared to their pretreatment values. Thus, our results indicate considerable oxidative stress in stroke.

Double phototherapy in jaundiced term infants with hemolysis.

OBJECTIVE: To compare the efficacy of double phototherapy and conventional phototherapy in term newborn infants with hemolytic jaundice. METHOD: Full-term infants with evidence of severe hemolysis on the peripheral blood smear, whose serum bilirubin levels were between 15-21 mg/dl were divided into 2 groups, depending on the availability of the phototherapy bed. Group 1 infants received double phototherapy consisting of conventional (single) phototherapy plus an extra light source from a phototherapy bed (Medela Billibed, Switzerland). Group 2 infants received only conventional phototherapy. Maternal and infants' blood groups and Rh, direct Coomb's test, G6PD screening test and hematocrit were determined on every infant. Phototherapy was given until the serum bilirubin level dropped to < or = 13 mg/dl. Exchange transfusion was indicated when the serum bilirubin level was > or = 21 mg/dl after phototherapy had been given for 4-6 hours. RESULTS: There were 110 infants included in this study, 62 and 48 in group 1 and 2 respectively. There was no statistical difference in terms of birth weight, sex ratio, proportion of breast feeding infants and the initial hematocrit level. However, the initial mean +/- SD of bilirubin level of group 1 infants was higher than that of group 2, (17.7 +/- 1.6 mg/dl vs 16.2 +/- 0.9 mg/dl, p < 0.001). Causes of hemolysis could be determined in 74 infants; 27 (24.5%), 39 (35.5%) and 8 (7.3%) infants had ABO incompatibility, G6PD deficiency and both ABO incompatibility and G6PD deficiency respectively. Rate of bilirubin reduction in group 1 infants was significantly faster, (3.3 +/- 2.4 mg/dl/24 h vs 2.1 +/- 1.1 mg/dl/24 h, p < 0.01). Duration of phototherapy was also shorter in group 1 infants, (45.8 +/- 29.7 hours vs 58.5 +/- 26.0 hours, p < 0.05). Four infants failed to respond to the phototherapy that was assigned. Two infants in group 2 had to be switched to receive double phototherapy because of rapid rising of serum bilirubin. One in each group needed exchange transfusion. CONCLUSION: The study demonstrated that double phototherapy is more efficient than conventional phototherapy in term infants with severe jaundice caused by hemolysis.

Antimicrobial susceptibility, hemolysis, and hemagglutination among aeromonas ssp. isolated from water of a bovine abattoir

The presence of Aeromonas ssp. in food has been demonstrated. They are often introduced from water, which is the natural habitat of many species and is thought to be the main source of contamination. The occurrence of Aeromonas ssp. was investigated in 70 water samples of a bovine abattoir. Aeromonas ssp. were present in 21.4(per cent) of water samples. A.hydrophila was isolated from 11.4(per cent) of supplying water samples and from 25.7(per cent) of the water drained from carcasses, whereas A. sobria was sole isolated from 5.7(per cent) of supplying water samples. Although greater number of positive samples were from water drained from carcasses, only A.hydrophila isolates were present. This suggests that the supplying water is the source of contamination. The antibiotic susceptibility testing revealed all strains were resistant to ß-lactam antibiotics. However, the susceptibility to other antimicrobials was variable, being A.hydrophila more resistant than A. sobria strains. The investigation for virulence factors revealed positive reactions of hemolysis and hemagglutination. The results indicate that Aeromonas ssp. are present in the supplying water system. These microorganisms may be a potential contaminant of carcasses and widespread in derived food.

Hemolytic activity of fresh isolates and clones of trichomonas gallinae

In in vitro assay the hemolytic activity of live isolates and clones of trichomonas gallinae was investigated. The fresh isolates and clones were tested against human erythrocytes of groups A, B, AB and O, and against erythrocytes of six adult animals of different species (rabbit, rat, chicken, horse, bovine and sheep). Results showed that each of the isolates and clones tested lysed all human blood groups, as well as rabbit, rat, chicken, horse, bovine and sheep erythrocytes. No hemolysin released by the parasites could be identified. Parasite culture supernatants of hemolysis assays, tested in the presence of human erythrocytes did not induce any hemolytic activity. Trichomonads culture supernatants from 18, 24, and 48 hr extracts of sonicated parasites or cold killed organisms tested with human erythrocytes did not exhibit hemolysis. Although an hemolytic activity of T. gallinae was clearly demonstrated, a relationship between hemolysis and cell pathogenicity is not yet clearly established

Hemolitic aspects of strains and clones of trichomonas vaginalis

Se investigó la actividad hemolítica de 11 cepas y 6 clones vivos de trichomonas vaginalis. Las cepas y los clones fueron subsecuentemente estudiados frente a los eritrocitos de 7 especies animales adultas. Cada una da 11 cepas y 6 clones lisó los eritrocitos de todos los grupos sanguineos humanos, lo mismo que los de conejo, rata, pollo, caballo, bovino y ovino. No se detectó la liberación de hemolisina por el parásito (cepas y clones). Los resultados sugieren que la acividad hemolítica no es debida a la liberación de hemolisina por la T. vaginalis o por un producto de su metabolismo

Increased glutathione cycling and vitamin E of P. falciparum infected erythrocytes fail to prevent spontaneous haemolysis.

In an attempt to understand the pathogenesis of anaemia in Plasmodium falciparum infection, the status of erythrocyte glutathione and vitamin E content in relation to the susceptibility of infected red cells to peroxide haemolysis was examined. Synchronized cultures of the parasite with either ring-, trophozoite or schizont-infected red cells showed a gradual increase in the reduced glutathione content which was significantly higher (p < 0.05) in schizont-infected cells. Trophozoite-infected cells revealed significant increase in oxidized glutathione (p < 0.01) suggesting an increase in glutathione utilization during active erythrocytic schizogony of the parasites. The membrane antioxidant vitamin E also showed an increased accumulation in trophozoite- and schizont-infected red cells (p < 0.05) but not in the uninfected or ring-infected erythrocytes. Despite a favourable change in these antioxidants, the infected as well as uninfected red cells from parasite cultures showed enhanced peroxide haemolysis (uninfected, p < 0.05; ring-rich, p < 0.05, trophozoite- and schizont-rich, p < 0.001). The study provided direct evidence for enhanced susceptibility of red cells to lysis, including those of uninfected cells exposed to parasite products. This might explain the cause for much higher red cell loss and anaemia during P. falciparum infection than all the infected cells put together.