Labile Plasma Iron Generation After Intravenous Iron is Time-dependent and Transitory in Patients Undergoing Chronic Hemodialysis

Iron supplementation in hemodialysis patients is fundamental to erythropoiesis, but may cause harmful effects. We measured oxidative stress using labile plasma iron (LPI) after parenteral iron replacement in chronic hemodialysis patients. Intravenous iron saccharate (100 mg) was administered in patients undergoing chronic hemodialysis (N = 20). LPI was measured by an oxidant-sensitive fluorescent probe at the beginning of dialysis session (T0), at 10 min (T1), 20 min (T2), and 30 min (T3) after the infusion of iron and at the subsequent session; P < 0.05 was significant. The LPI values were significantly raised according to the time of administration and were transitory: -0.02 +/- 0.20 mu mol/L at the beginning of the first session, 0.01 +/- 0.26 mu mol/L at T0, 0.03 +/- 0.23 mu mol/L at T1, 0.09 +/- 0.28 mmol/L at T2, 0.18 +/- 0.52 mmol/L at T3, and -0.02 +/- 0.16 mmol/L (P = 0.001 to 0.041) at the beginning of the second session. The LPI level in patients without iron supplementation was -0.06 +/- 0.16 mmol/L. Correlations of LPI according to time were T1, T2, and T3 vs. serum iron (P = 0.01, P = 0.007, and P = 0.0025, respectively), and T2 and T3 vs. transferrin saturation (P = 0.001 and P = 0.0003, respectively). LPI generation after intravenous saccharate administration is time-dependent and transitorily detected during hemodialysis. The LPI increment had a positive correlation to iron and transferrin saturation.

Fatores de risco para morte em pacientes diabéticos e não diabéticos em tratamento hemodialítico

A mortalidade dos pacientes diabéticos, quando iniciam tratamento hemodialítico, ainda é muito elevada, significativamente maior do que a dos pacientes não diabéticos. As doenças cardíacas são a principal causa de morte nestes pacientes. O diabetes, por si só, está associado a uma alta prevalência de hipertensão, doença cardiovascular e insuficiência cardíaca, resultando em morbi-mortalidade significativas. Tradicionalmente, a mortalidade tem sido associada à cardiopatia isquêmica. A mortalidade cardiovascular, entretanto, não está relacionada apenas à isquemia, mas também à insuficiência cardíaca e à morte súbita. O objetivo deste estudo foi analisar o papel da doença cardiovascular como fator prognóstico para a morte de pacientes diabéticos e não diabéticos, que iniciam hemodiálise, levando em consideração outros fatores. Este foi um estudo prospectivo de uma coorte de 40 pacientes diabéticos e 28 não diabéticos, que iniciaram programa de hemodiálise, de agosto de 1996 a junho de 1999, em 5 hospitais de Porto Alegre, Brasil. O tempo total de acompanhamento foi de 4,25 anos. A avaliação inicial, realizada entre o 20 e o 30 mês de hemodiálise, incluiu: um questionário com características demográficas, história do diabetes e suas complicações, história de hipertensão e acidente vascular cerebral; o exame físico incluindo avaliação nutricional e exame oftalmológico; e avaliação laboratorial com medidas de parâmetros nutricionais, bioquímicos, hormonais, perfil lipídico, e controle metabólico do diabetes, além da avaliação da adequação da diálise. Para a avaliação cardiovascular foram utilizados: questionário Rose, ECG em repouso, cintilografia em repouso e sob dipiridamol, e ecocardiograma bi-dimensional e com Doppler. A mortalidade foi analisada ao final dos 51 meses, e as causas de morte, definidas pelos registros médicos, atestados de óbito ou informações do médico assistente ou familiar. Na análise estatística, foram empregados o teste t de Student, o qui-quadrado (χ2) ou teste exato de Fisher. Para a análise da sobrevida, o método de Kaplan-Meier foi utilizado, e, para identificar os principais fatores associados à mortalidade, construiu-se um modelo de regressão múltipla de Cox. O nÍvel de significância adotado foi de 5%. Ao final do estudo, os pacientes diabéticos tiveram um índice de mortalidade significativamente mais elevado do que os pacientes sem diabetes (47,5% vs. 7,1%; P=0,0013, log rank test). Na análise de Cox, o padrão pseudonormal ou restritivo de disfunção diastólica esteve associado a um risco de 3,2 (IC 95%:1,2-8,8; P=0,02), e a presença de diabetes, a um risco de 4,7 (IC 95%:1,03-21,4; P=0,04) para a morte. Concluiu-se que a disfunção diastólica do ventrículo esquerdo foi o principal preditor de mortalidade nesta coorte de pacientes que estão iniciando tratamento hemodialítico.

Avaliação da reprodutibilidade dos parâmetros de adequação da hemodiálise crônica

Justificativa: Doses inadequadas de diálise estão associadas a maior morbidade e mortalidade em pacientes com uremia terminal em tratamento hemodialítico. Atualmente os métodos mais utilizados para medir a adequação da hemodiálise baseiam-se no cálculo da depuração fracional de uréia (Kt/V) e da taxa de redução da uréia (URR). Nesse estudo avaliou-se a reprodutibilidade do Kt/V e da URR e analisou-se o número aceitável de medidas mensais destes parâmetros para determinar de forma fidedigna a adequação da hemodiálise. Métodos: Avaliamos 43 pacientes clinicamente estáveis, em cinco sessões de hemodiálise (sessões 1 a 5), durante três semanas. Três diálises consecutivas na primeira semana (sessões 1, 2, 3) e duas sessões de meio de semana, nas duas semanas subseqüentes (sessões 4 e 5). Resultados: Não houve diferença entre a média dos Kt/Vs obtidos em diálises seqüenciais (1, 2 e 3) comparada a média dos Kt/Vs obtidos em diálises no meio da semana (2, 4 e 5). O mesmo aconteceu com a URR e com os coeficientes de variação do Kt/V e da URR. Também não encontramos diferença entre uma medida mensal (Kt/V 2) e três medidas mensais (média dos Kt/Vs 2, 4 e 5). O mesmo ocorreu com a URR. A diferença entre o Kt/V 2 e a média dos Kt/Vs 2, 4 e 5 foi de – 0,02 unidades e entre a URR 2 em relação a média das URRs 2, 4 e 5 foi de – 0,5%. Além disso, se fizermos apenas uma medida mensal (Kt/V 2) 80% dos pacientes estarão a uma distância de no máximo 0,16 unidades abaixo da média dos Kt/Vs 2, 4 e 5 e no máximo 0,12 unidades acima. Em relação a URR 80% dos pacientes estarão a uma distância de no máximo 4,37% abaixo da média das URRs 2, 4 e 5 e no máximo 3,37% acima. O grau de concordância entre o Kt/V 2 e a média dos Kt/Vs 2, 4 e 5 é bom para pontos de corte do Kt/V igual ou superior a 1,3. No caso da URR a concordância é boa para pontos de corte acima de 65%. Conclusão: Concluímos que nesta população de pacientes clinicamente estáveis os parâmetros de adequação da hemodiálise mostraram-se reprodutíveis não havendo necessidade de aumentar o número de medidas mensais da quantidade de diálise ofertada.

Curso evolutivo e fatores de progressão da nefropatia diabética em pacientes com diabete melito tipo 2

A nefropatia diabética (ND) é uma complicação microvascular freqüente, que acomete cerca de 40% dos indivíduos com diabete melito (DM). A ND associa-se a significativo aumento de morte por doença cardiovascular. É a principal causa de insuficiência renal terminal em países desenvolvidos e em desenvolvimento, representando, dessa forma, um custo elevado para o sistema de saúde. Os fatores de risco para o desenvolvimento e a progressão da ND mais definidos na literatura são a hiperglicemia e a hipertensão arterial sistêmica. Outros fatores descritos são o fumo, a dislipidemia, o tipo e a quantidade de proteína ingerida na dieta e a presença da retinopatia diabética. Alguns parâmetros de função renal também têm sido estudados como fatores de risco, tais como a excreção urinária de albumina (EUA) normal-alta e a taxa de filtração glomerular excessivamente elevada ou reduzida. Alguns genes candidatos têm sido postulados como risco, mas sem um marcador definitivo. O diagnóstico da ND é estabelecido pela presença de microalbuminúria (nefropatia incipiente: EUA 20-199 μg/min) e macroalbuminúria (nefropatia clínica: EUA ≥ 200 μg/min). À medida que progride a ND, aumenta mais a chance de o paciente morrer de cardiopatia isquêmica. Quando o paciente evolui com perda de função renal, há necessidade de terapia de substituição renal e, em diálise, a mortalidade dos pacientes com DM é muito mais significativa do que nos não-diabéticos, com predomínio das causas cardiovasculares. A progressão nos diferentes estágios da ND não é, no entanto, inexorável. Há estudos de intervenção que demonstram a possibilidade de prevenção e de retardo na evolução da ND principalmente com o uso dos inibidores da enzima conversora da angiotensina, dos bloqueadores da angiotensina II e do tratamento intensivo da hipertensão arterial. Os pacientes podem entrar em remissão, ou até mesmo regredir de estágio. A importância da detecção precoce e da compreensão do curso clínico da ND tem ganhado cada vez mais ênfase, porque a doença renal do DM é a principal causa de diálise no mundo e está associada ao progressivo aumento de morte por causas cardiovasculares.

Prevalência da deleção 4977pb do DNA mitocondrial em pacientes com doença renal crônica em tratamento conservador ou submetidos a hemodiálise no sul do Brasil

Introdução. Danos no DNA mitocondrial (DNAmt) têm sido descritos em pacientes com doença renal crônica (DRC). Estes danos podem ser avaliados através da deleção 4977pb do DNAmt em diversos tecidos. Métodos. Identificamos a prevalência da deleção 4977pb do DNAmt através da técnica da reação em cadeia da polimerase (PCR) no sangue de pacientes com DRC em tratamento conservador (creatinina >2mg/dl) ou submetidos a hemodiálise. Resultados. A freqüência da ocorrência da deleção do DNAmt foi de 73.1% (38/52) nos pacientes com DRC submetidos a hemodiálise, 57.1% (27/42) nos pacientes com DRC em tratamento conservador e 27.8% (15/54) nos controles (P< 0.001). Não encontramos aumento da freqüência desta deleção em relação a idade dos pacientes com DRC (P= 0.54) ou ao tempo de diálise (P= 0.70). Conclusão. Danos no DNAmt podem ser induzidos pela DRC em especial nos pacientes submetidos a hemodiálise. Desta forma, a deleção 4977pb do DNAmt pode servir como um marcador de danos moleculares em pacientes com DRC.

Redução da morbi-mortalidade na síndrome de hellp completa com o uso de altas doses de dexametasona

Objective: To determine the clinical maternal and neonatal outcomes in HELLP syndrome patients treated with dexamethasone who either developed renal injury or renal insufficiency and to identify predictive values of urea and creatinine for the identification of subjects with HELLP syndrome at risk of developing renal insufficiency. Methods: Non-radomized intervention study of dexamethasone use in HELLP syndrome. A total of 62 patients were enrolled at Maternidade Escola Januário Cicco (MEJC). Patients received a total of 30 mg of dexamethasone IV, in three doses of 10 mg every 12 hours. A clinical and laboratory follow up were performed at 24, 48 and 72 hours. Patients were followed up to 6 months after delivery. Patients were grouped in accordance to renal function, i.e, normal and some type of renal lesion. Renal lesion was considered when creatinine was equal or greater than 1.3 mg/dl and diuresis less than 100 ml in 4 hours period and renal insufficiency was defined when dialysis was needed. Results: A total of 1230 patients with preeclampsia were admitted at MEJC. Of those 62 (5%) developed HELLP syndrome. There was no statistical difference in the groups with renal involvement or normal renal function with respect to the demographics, type of anesthesia used and delivery, and weight of the newborn. An improvement in the AST, ALT, LDH, haptoglobine, antithrombine, fibrinogenen and platelets was observed within 72 hours after dexamethosone use. There was a significant increase in the diuresis within the interval of 6 hours before the delivery and 24 hours after it. Of the 62 patients, 46 (74. 2%) had normal renal function and 16 (25.8%) evolved with renal lesion, with 5 (8.1%) needing dialysis. These 5 patients who received dialysis recovered the xi renal function. The delay in administering dexamethasone increased in 4.6% the risk of development of renal insufficiency. Patients with renal insufficiency had received significantly more blood products than subjects without renal lesion (p=0.03). Diuresis, leukocytes, uric acid, urea, creatinine were significantly different between the groups with normal renal function, renal lesion and renal insufficiency. The levels of creatinine 1.2mg/dl and uric acid 51mg/dl, at admission are predictive of subjects who will evolve with renal lesion (p<0.001). Maternal mortality was 3.2%. None of the subjects with renal insufficiency evolved with chronic renal disease. Conclusions: Dexamethasone in patients with HELLP syndrome seems to reduce significantly the hepatic microthrombosis and normalize hemostasis as seen by improvement of liver function. Renal injury can be considered, in HELLP syndrome, when creatinine levels are greater than 1.3 mg/dl and diuresis less than 100 ml/h in interval of 4 hours. The level of creatinine greater than 1.2 mg/dl and urea greater than 51mg/dl are predictive of subjects with HELLP syndrome who will develop renal injury. Patients who receive more red cell packs develop renal insufficiency. Finally, the delay in administering dexamethasone increases the risk of developing renal insufficiency

Marcadores nutricionais e inflamatórios e sua associação com a morbimortalidade em hemodiálise

Background: Malnutrition, inflammation and comorbidities are frequent in patients with chronic renal failure in hemodialysis (HD), contributing for morbidity and mortality. Aims: To evaluate the correlation between anthropometric, laboratory parameters, bioelectrical impedance (BIA) and inflammatory markers with the morbidity and mortality of patients in HD, as well as the impact of its alterations throughout 12 months. Methods: 143 patients of a dialysis facility in Northeast Brazil were evaluated throughout 18 months. Patients with more than 3 months on dialysis, older than 18 years, without amputation of hands and feet, were included in the study. We performed a clinical (subjective global assessment - SGA), anthropometric (BMI, percent of ideal weight, MAC, MAMC, MAMA, percent of fat mass and TSF), laboratory (albumin, creatinine, lymphocyte count as nutritional markers and CRP, IL-6 and TNF- as inflammatory markers) evaluation and BIA (reactance, phase angle and percent of body cell mass) at the beginning of study and after 3, 6 and 12 months of follow-up. The association between study variables and deaths and hospitalizations in 6 and 12 months was investigated. The variable with significance < 10% in the univariate analysis had been enclosed in a multivariate logistic regression analysis. We also investigated the risk of mortality and hospitalization associated with differences in measurements of the variables at baseline and six months later. Results: Patients were aged 52.2 ± 16.6 years on the average, 58% were male, and mean dialysis vintage was 5.27 ± 5.12 years. The prevalence of malnutrition varied from 7.7-63.6%, according to the nutritional marker. The variables associated with morbidity and mortality in 6 and 12 months had been creatinine ≤ 9.45 mg/dl, phase angle ≤ 4.57 degrees, BMI ≤ 23 kg/m2, age ≤ 64.9 years, reactance ≤ 51.7 ohms; Charlson´s index ≥ 4 and socioeconomic status ≤ 7. During six months of follow up, decrease in albumin was associated with significantly higher mortality risk. Conclusions: This study detected that the best predictors of morbidity and mortality between nutritional and inflammatory markers are phase angle, reactance, creatinine and BMI and that changes in albumin values over six 107 months provide additional prognostic information. The authors believe that parameters of BIA may detect early changes in nutritional status and emphasize that longitudinal studies with larger number of patients are necessary to confirm these data and to recommend BIA as a routine nutritional evaluation in HD patients

Candida parapsilosis complex water isolates from a haemodialysis unit: biofilm production and in vitro evaluation of the use of clinical antifungals

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diagnósticos de enfermagem em pacientes submetidos à hemodiálise: semelhanças entre o modelo de adaptação e a NANDA internacional

The nurses in the hemodialysis has an important role in the nursing process implementation, in the context of a theoretical referential. Among the nursing theories, highlights the Roy´s adaptations model, who considers a person as an holistic adaptive system that aims to adapt customers to different living conditions. Thus, it is believed that the Roy´s nursing process will guide nursing care to patients on dialysis. Therefore, the study aimed to analyze the nursing diagnosis present in patients with chronic kidney disease on hemodialysis based on the theoretical model of Roy and NANDA-International. Descriptive and cros-sectional study, performed at a dialysis center in a city in northeastern Brazil. Sample of 178 patients and consecutive sampling by convenience. Data collection ocurred from October/2011 until February/2012, through interview and physical examination forms. Data analysis was initiated by clinical reasoning, diagnosis judgment and similarity relation. Then, the data were entered into SPSS program, 16.0 version, generating descriptive statistics. The project was approved by the Ethics Research Committee (protocol nº 115/11) with a Presentation Certificate for Ethics Appreciation (in 0139.0.051.000-111) and was funded by the Universal edict MCT / CNPq 14/2010. The results revealed that most patients were male (52.2%), married (62.9%) and residents in the Natal´s metropolitan region (54.5%). The mean age was 46.6 years and the years of study, 8,5. Regarding nursing diagnosis obtained an average of 6.6, especially: Risk of Infection (100%), excessive fluid volume (99.4%) and hypothermia (61.8%). On the other hand the adaptive problems average was 6.4, and the most common: intracellular fluid retention (99.4%); Hyperkalemia (64.6%); Hypothermia (61.8%) and edema (53.9%). Were established 20 similarity relations between the NANDA-International nursing diagnosis and adaptive problems of Roy, namely: risk of falls / injury risk and potential for injury, impaired physical mobility and walking mobility and / or restricted coordination, dressing self-care deficit and loss of self-care ability; hypothermia and hypothermia; impaired skin integrity and impaired skin integrity; excessive fluid volume and intracellular fluid retention / Hyperkalemia / Hypocalcemia / edema; imbalanced nutrition: less than body requirements and Nutrition less than the body's needs; constipation and constipation, acute pain and acute pain, chronic pain and chronic pain, sensorial perception disturbed: visual, tactile and auditory disabilities and a primary sense: sight, hearing and tactile; sleep deprivation and insomnia, fatigue and intolerance to activities; ineffective self health and fails in the role; sexual dysfunction and sexual dysfunction; situational low self-esteem and low self-esteem, and diarrhea and diarrhea. We conclude that there is similarity between the typologies and was required a model´s analysis, because they present different ways to establish the nursing diagnosis. Moreover, the nursing process use, under the context of a theory and a classification system, subsidizes the care and contributes to the strengthening of nursing science

Acurácia dos indicadores clínicos do diagnóstico de enfermagem volume de líquidos excessivo em pacientes submetidos à hemodiálise

Trasnversal study, with the objective of evaluating the accuracy of clinical indicators of nursing diagnosis excessive fluid volume in patients undergoing hemodialysis. The study occurred in two stages, the first consisted of the evaluation of the diagnostic indicators in study; and the second, the diagnostic inference conducted by nurse diagnosticians. The first stage occurred from december 2012 to april 2013, in a University Hospital and a Hemodialysis Clinic in Northeastern of Brazil, with a sample of 100 chronic renal failure patients on hemodialysis. The data were selected through an interview form and a physical examination, organized into spreadsheets and analyzed as to the presence or absence of the indicators of diagnosis excessive fluid volume. In the second step, the spreadsheets were sent to three nurses diagnosticians, who judged the presence or absence of diagnosis in the clientele searched. This step was conducted from july to september 2013. For analysis of the data, we used descriptive and inferential statistics. In the descriptive analysis, we used measures of central tendency and dispersion. In inferential analysis, we used the tests Chi- square, Fisher and prevalence ratios. The accuracy of the clinical indicators pertaining to the diagnosis were measured as to the specificity, sensitivity, predictive values, likelihood ratios and Diagnostic Odds Ratio. Also developed a logistic regression. The results were organized in tables and discussed with literature. This study was approved by the Ethics Committee in Research of the Federal University of Rio Grande do Norte, with Presentation Certificate for Ethics Appreciation nº 08696212.7.0000.5537. The results revealed that the diagnosis studied was present in 82% of patients. The characteristics with prevalence above 50 % that stood out were: azotemia, decreased hematocrit, electrolyte imbalance, intake exceeds output, anxiety, edema, decreased hemoglobin, oliguria and blood pressure changes. Eight defining characteristics were presented statistically significant association with the nursing diagnosis investigated: pulmonary congestion, intake exceeds output, electrolytes imbalance, jugular vein distension, edema, weight gain over short period of time, agitation and adventitious breath sounds. Among these, the 10 characteristics which showed higher prevalence ratios were: edema and weight gain over short period of time. The features with the highest sensitivity were edema, electrolytes imbalance and intake exceeds output and the standing out with greater specificity were: anasarca, weight gain over short period of time, change in respiratory pattern, adventitious breath sounds, pulmonary congestion, agitation and jugular vein distension. The indicators jugular vein distension, electrolytes imbalance, intake exceeds output, increased central venous pressure and edema, together, were identified in the logistic regression model as the most significant predictors. It is concluded that the identification of accurate clinical indicators allow a good prediction of the nursing diagnosis of excessive fluid volume in patients undergoing hemodialysis in order to assist the nurse in the inference process, which will contribute to the success of patient care. In addition, nurses will consider for diagnostic inference not only his clinical experience, but also scientific evidence of the occurrence of excessive fluid volume, contributing to the control of volemia in these patients

Obtenção de oligossacarídeos N-ligados às glicoproteínas dos líquens Sticta tomentosa e Sticta damaecornis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Saphenofemoral arteriovenous fistula as hemodialysis access

Background: An upper limb arteriovenous (AV) fistula is the access of choice for haemodialysis (HD). There have been few reports of saphenofemoral AV fistulas (SFAVF) over the last 10-20 years because of previous suggestions of poor patencies and needling difficulties. Here, we describe our clinical experience with SFAVF.Methods: SFAVFs were evaluated using the following variables: immediate results, early and late complications, intraoperative and postoperative complications (up to day 30), efficiency of the fistula after the onset of needling and complications associated to its use.Results: Fifty-six SFAVF fistulas were created in 48 patients. Eight patients had two fistulas: 8 patent (16%), 10 transplanted (20%), 12 deaths (24%), 1 low flow (2%) and 20 thrombosis (39%) (first two months of preparation). One patient had severe hypotension during surgery, which caused thrombosis of the fistula, which was successfully thrombectomised, four thrombosed fistulae were successfully thrombectomised and revised on the first postoperative day. After 59 months of follow-up, primary patency was 44%.Conclusion: SFAVF is an adequate alternative for patients without the possibility for other access in the upper limbs, allowing efficient dialysis with good long-term patency with a low complication rate.

Occurrence of fungi in water used at a haemodialysis centre

Aims: The aim of this study was to identify and determine the diversity, occurrence and distribution of fungi in water used at a haemodialysis centre.Methods and Results: Samples in the hydraulic circuit for the distribution of the water, dialysate samples and samples of sterilization solution from dialysers were collected over a 3-month period, and 500 ml of each sample was filtered through membranes. All together 116 isolates of fungi were recovered from 89% of all water samples collected inside the haemodialysis unit, with prevalence of moulds in tap water samples and of yeasts in dialysate samples. Fusarium spp. was the most abundant genus found, whereas Candida parapsilosis was the predominant yeast species.Conclusions: This study demonstrated that various fungi were present in the water system. These data suggest the inclusion of the detection and quantification of fungi in the water of haemodialysis.Significance and Impact of the Study: The recovery of fungi from aqueous haemodialysis environments implies a potential risk for haemodialysis patients and indicates the need for continuous maintenance and monitoring. Further studies on fungi in haemodialysis water systems are required to investigate the organism ability to persist, their role in biofilm formation and their clinical significance.

MICROBIOLOGICAL CONTAMINATION of A HEMODIALYSIS CENTER WATER DISTRIBUTION SYSTEM

The microbiological monitoring of the water used for hemodialysis is extremely important, especially because of the debilitated immune system of patients suffering from chronic renal insufficiency. To investigate the occurrence and species diversity of bacteria in waters, water samples were collected monthly from a hemodialysis center in upstate São Paulo and tap water samples at the terminal sites of the distribution system was sampled repeatedly (22 times) at each of five points in the distribution system; a further 36 samples were taken from cannulae in 19 hemodialysis machines that were ready for the next patient, four samples from the reuse system and 13 from the water storage system. To identify bacteria, samples were filtered through 0.22 mu m-pore membranes; for mycobacteria, 0.45 mu m pores were used. Conventional microbiological and molecular methods were used in the analysis. Bacteria were isolated from the distribution system (128 isolates), kidney machine water (43) and reuse system (3). Among these isolates, 32 were Gram-positive rods, 120 Gram-negative rods, 20 Gram-positive cocci and 11 mycobacteria. We propose the continual monitoring of the water supplies in hemodialysis centers and the adoption of effective prophylactic measures that minimize the exposure of these immunodeficient patients to contaminated sources of water.

Some Biochemical properties of polyphenoloxidase from spearmint (Mentha arvensis)

Polifenoloxidase (PPO, EC 1.14.18.1) extraída de folhas de Mentha arvensis foi isolada por precipitação com (NH4)2SO4 e diálise extensiva. Seu pH e temperatura ótimos variaram com o substrato. A PPO apresentou atividade com vários difenóis. Valores de Km foram 0,825; 0,928 e 7,41 mM para ácido caféico, 4-metilcatecol e catecol, respectivamente. Na inativação térmica, 50% da enzima foi inativada após 60 e 15 segundos a 70 e 75ºC, respectivamente. A medida de atividade residual mostrou um efeito estabilizante de sacarose a várias temperaturas e uma energia de ativação (Ea) para inativação aumentando com a concentração de sacarose de 0 a 40% (p/p). Valores de energias de ativação de 78,13; 80,37; 82,79 and 81,00 kJ/Mol foram encontradas para 0, 15, 30 e 40% de sacarose, respectivamente. A PPO foi inibida pelos ácidos ascórbico, benzóico, cinamico, ferulico, p-cumárico, protocatéquico, além de metabisulfito de sódio, resorcinol e pirogalol. Os valores de Ki mostram que o ácido ascórbico foi o mais efetivo inibidor. O tipo de inibição foi determinado para cada inibidor.