Are salivary NO2- / NO2- and NO3- levels biomarkers for dental caries in children? Systematic review and meta-analysis.

The literature is conflicting regarding salivary nitrite (NO2-)/nitrite and nitrate (NO2- and NO3-) levels in children affected by dental caries. For this reason, a systematic review to provide a consensus on the subject was propose, whose objective is to verify whether these molecules could be used as biomarkers in children with caries. A comprehensive search was performed on online database and eleven articles were included in the meta-analysis. The methodological quality of studies was assessed by Newcastle-Ottawa Scale recommended for case-control studies and by AXIS tool for cross-sectional studies. Grading of Recommendations Assessment, Development and Evaluation was used for the assessment of the certainty of the evidence for each outcome. The results showed lower NO2- levels in the group of children affected by dental caries (SMD = -2.18 [-3.24, -1.13], p < 0.01). Age, saliva collection and methods of evaluation can impact the results. When evaluating the severity of the condition, an important variation was detected in relation to the different evaluation methods NO2-/NO2- and NO3-. In conclusion, based on the evidence presented, the results suggest that NO2- levels in saliva are a possible biomarker of dental caries. Results should be evaluated with caution due to the very low evidence from primary studies. Longitudinal studies are necessary to strengthen this hypothesis.

Applicability of the probiotic Lactiplantibacillus plantarum BFL as an adjunct culture in a dry fermented sausage.

The addition of probiotic bacteria to a meat batter allows the development of functional fermented sausages. The aim of this work was to study the effect of microencapsulated Lactiplantibacillus plantarum BFL (EP) and as free cells (FP) on microbiological, physicochemical, and sensory parameters of fermented sausages during the drying stage and on the product ready for consumption. The microencapsulation of L. plantarum BFL did not improve its viability during the drying stage. In addition, sausages inoculated with L. plantarum BFL (FP and EP) caused lower residual nitrites values, pH values and Escherichia coli counts than the Control (C). However, only the presence of free cells of L. plantarum BFL (FP) caused a decrease in the Enterobacteriaceae and mannitol salt-positive Staphylococcus counts. In the sensory analysis, no significant differences were found in the acceptability of the different sausages. However, the acidity in probiotic sausages (FP and EP) was an attribute that consumers highlighted. The probiotic L. plantarum BFL could adapt and survive at high doses in the matrix of an industrial fermented sausage. Therefore, its use could represent a strategy both for biocontrol of pathogens and for the development of functional meat products.

Poppers use and HIV infection-a literature review.

INTRODUCTION: During the HIV surge in the 1980s, inhaled volatile nitrites (poppers) were hypothesized as a possible cause of the AIDS. Later it was found that poppers use was not the cause but rather a marker associated with HIV acquisition and sexual behaviors without the use of prevention tools. OBJECTIVES: This article reviews the available literature regarding the association between poppers use and newly acquired HIV, aiming to support the hypothesis that there is no causal association between nitrites use and HIV transmission and to discuss other contributing factors. METHODS: We searched all studies published until March 2022 that discussed poppers use and HIV. We extracted relevant information, such as authors and publication year, country where the study was conducted, study design, characteristics of the population, number of participants, objectives of the study, methods, results, and limitations. RESULTS: The search identified 1956 abstracts, and 1915 were excluded after title review. Forty-one abstracts were assessed, and 17 studies met the inclusion criteria. The majority of the studies found an association between nitrites use and HIV transmission. Four studies associated HIV transmission with sexual behavior without the use of prevention tools, and 5 articles associated nitrites use with this kind of sexual behavior. CONCLUSIONS: Our findings show a complex association among nitrites use, sexual behaviors without the use of prevention tools, and sexually transmitted infections; furthermore, it is impossible to make causal inferences between poppers use and HIV disease. The data suggest that it is vital to consider this substance use when planning health policies for specific populations, such as men who have sex with men, focusing on harm reduction strategies, psychoeducation, and orientations on sex with the use of prevention tools. CLINICAL TRIAL REGISTRATION: PROSPERO CRD42020181437. https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=181437.

Cocaine and Volatile Nitrite-Induced Methemoglobinemia; a Case Report and Treatment Approach Review.

Cyanosis is typically a sign of a potentially life-threatening condition in the emergency department and requires immediate workup and treatment. This case report highlights the diagnostic reasoning and clinical approach to cocaine- and volatile nitrite-induced methemoglobinemia (MHG). MHG is a rare, life-threatening cause of cyanosis. The diagnosis must be suspected in the emergency department in the presence of hypoxia and cyanosis disproportionate to cardiopulmonary repercussions and refractory to oxygen supplementation. Acquired causes are more prevalent than genetics, and recreational drugs should be highly suspected. Despite the rarity of this situation, cyanosis precipitants and the specificities of each hemoglobinopathy are reviewed in this article.

Influence of environmental variables on the spatiotemporal dynamics of water quality in Buenaventura Bay, Colombian Pacific.

Tropical estuaries are productive dynamic ecosystems where water quality is mediated by physicochemical and biological processes and by fluvial and anthropogenic discharges. The objective of the study was to determine the influence of environmental variables on the spatiotemporal dynamics of water quality in Buenaventura Bay, which is a highly impacted estuary. Sampling was carried out during the dry and rainy season, at three depths, in four stations that represent the environmental gradient of the bay. Temperature, total dissolved solids, salinity, dissolved oxygen, and pH were determined for each sample. In addition, alkalinity, phosphates, nitrites, and nitrates as indicators of water quality were also measured. The estuary was classified as meso- and polyhaline, with appropriate oxygen and pH conditions and spatiotemporal gradients of temperature and solids mediated by river discharges. Significant variations were found in the physicochemical variables by season, with maximum salinity, pH, and solids in the dry season and oxygen and temperature in the rainy season. Likewise, most of these environmental variables were higher in the outer zone of the estuary and lower in the inner stations. Alkalinity and nitrite values were within the permitted ranges, while phosphates and nitrates indicated low water quality. There was a significant direct influence of temperature and oxygen on alkalinity and nitrites. However, for phosphates, no significant influence of environmental variables was found, suggesting a greater influence by fluvial and anthropogenic discharges, which produce a decrease in the environmental quality of the estuary.

Salivary nitrite and systemic biomarkers in obese individuals with periodontitis submitted to FMD

Abstract The objective of this 9-month clinical study is to assess the impact of one-stage full-mouth disinfection (FMD) on salivary nitrite levels and systemic biomarkers and its correlation with total subgingival bacterial load in obese and non-obese patients with periodontitis. In total, 94 patients (55 obese and 39 non-obese) were initially evaluated, seven were lost during follow-up, resulting in 87 individuals at the end of the study. Outcomes were assessed at baseline, 3, 6, and 9 months post periodontal treatment by FMD. Salivary nitrite levels were determined using Griess reagent. Blood samples were collected to determine C-Reactive Protein (CRP), alkaline phosphatase and fasting blood glucose. Real-time PCR was used to determine the total subgingival bacterial load. FMD protocol resulted in increased salivary nitrite levels at 6- and 9-months post-treatment in the non-obese group (p<0.05). In obese individuals, FMD treatment led to an increase in salivary nitrite levels at 6 months (p<0.05); however, at 9 months, the nitrite levels returned to baseline levels. For both groups, the highest nitrite values were observed at 6 months. In addition, in both groups, FMD was associated with a decrease in biomarkers related to systemic inflammation and cardiovascular diseases, such as CRP (p<0.05) and alkaline phosphatase (p<0.05), and had no impact on the fasting blood glucose. This study demonstrates that obese patients with periodontitis present similar salivary nitrite levels when compared with non-obese individuals. FMD protocol resulted in increases in salivary nitrite levels and was associated with a positive impact on systemic biomarkers, regardless of obesity status.

Resumo O objetivo deste estudo clínico, é avaliar o impacto da desinfecção bucal completa (DBC) nos níveis de nitrito salivar e biomarcadores sistêmicos e sua correlação com a carga bacteriana subgengival total em pacientes obesos e não obesos com periodontite. No total, 94 pacientes (55 obesos e 39 não obesos) foram avaliados inicialmente, sete foram perdidos durante o estudo, resultando em 87 indivíduos ao final. Os resultados foram avaliados no início do estudo, 3, 6 e 9 meses após o tratamento periodontal por DBC. Os níveis de nitrito salivar foram determinados usando o reagente de Griess. Amostras de sangue foram coletadas para determinação da Proteína C Reativa (PCR), fosfatase alcalina e glicemia de jejum. A PCR em tempo real foi usada para determinar a carga bacteriana subgengival total. O protocolo de DBC resultou em níveis aumentados de nitrito salivar em 6 e 9 meses após o tratamento no grupo de não obesos (p <0,05). Em indivíduos obesos, o tratamento da DBC levou a um aumento nos níveis de nitrito salivar em 6 meses (p <0,05); no entanto, aos 9 meses, os níveis de nitrito voltaram aos níveis basais. Para ambos os grupos, os maiores valores de nitrito foram observados aos 6 meses. Além disso, em ambos os grupos, a DBC foi associada à diminuição dos biomarcadores relacionados à inflamação sistêmica e doenças cardiovasculares, como PCR (p <0,05) e fosfatase alcalina (p <0,05), e não teve impacto na glicemia de jejum. Este estudo demonstra que pacientes obesos com periodontite apresentam níveis de nitrito salivar semelhantes quando comparados a indivíduos não obesos. O protocolo de DBC resultou em aumentos nos níveis de nitrito salivar e foi associado a um impacto positivo nos biomarcadores sistêmicos, independentemente do status de obesidade.

Effect of water quality variation on fish assemblages in an anthropogenically impacted tropical estuary, Colombian Pacific.

In tropical estuaries, fish diversity varies spatially and temporally due to behavioral processes such as reproductive migrations, predator avoidance, and foraging, which are affected by water quality. Eutrophication is one of the main factors affecting water quality in estuaries. The objective of this study was to determine variation in fish assemblage explained by fluctuating water quality in the Buenaventura Bay. Fish were captured using artisanal trawl nets during the wet, dry, and transitional seasons at four sampling sites. Additionally, alkalinity; phosphate, nitrite, and nitrate concentrations; dissolved oxygen; pH; temperature; and suspended solids were measured. Multivariate analysis was used to assess the effect of water quality on fish assemblage. In Buenaventura Bay, the assemblage composition of Pseudupeneus grandisquamis, Daector dowi, and Citharichthys gilberti was affected by nitrate concentration. Moreover, large fish biomasses were associated with high nitrite concentration, intermediate salinity, and low dissolved oxygen, suggesting that these estuaries are dominated by species tolerant to poor water quality. Species richness was associated with low nitrate and phosphate concentrations, more suitable water quality indicators, and intermediate temperatures. These results suggest that the deteriorating water quality of estuaries as a result of the anthropogenic impact could increase dominance and decrease richness, resulting in structural changes of fish assemblages.

Effects of pH and nitrites on the toxicity of a cypermetrin-based pesticide to shrimps.

The Pantanal (Brazil) is a wetland region characterized by seasonal flooding. Hydrological cycles influence the water physicochemical parameters, causing seasonal variations in pH and nitrites. Thus, the objective of this study was to evaluate the effects of varying pH and nitrite concentrations on the toxicity of the cypermethrin-based pesticide Barrage®, considering both lethal (mortality) and sublethal endpoints (growth and development). Larvae of the endemic shrimp Macrobrachium pantanalense and of the estuarine Amazonian congener Macrobrachium amazonicum were exposed to cypermethrin (through Barrage®) under several pH levels (6.5, 7.5 and 8.5) or nitrite concentrations (0.1, 0.2 and 0.4 mg/L). The pH had direct effects on all the tested endpoints for both species. For M. pantanalense, the lethal effects of the cypermethrin formulation were more pronounced at low pH (96-h LC50 = 0.004 µg/L at pH 6.5, and 0.146 µg/L at pH 8.5). For M. amazonicum, an opposite response was observed, with increased toxicity of the formulation at high pH (96-h LC50 = 0.110 µg/L at pH 6.5 and 0.044 µg/L at pH 8.5). Variations in pH also seemed to modify the sublethal effects of the formulation on larval growth and development of M. pantanalense. Nitrite concentrations affected larval growth of both species, modifying also the effects of the cypermethrin formulation on the larval development of M. amazonicum. This work shows the importance of considering abiotic factors for risk assessment either due to possible direct effects on the physiology of organisms and/or due to interactions with other stressors, particularly in fragile biomes such as Pantanal.

Omeprazole and adenocarcinoma in the stomach of rats submitted to duodenogastric reflux: is there a protective effect?

Purpose: To investigate the role of omeprazole and nitrites on the gastric mucosa of rats submitted to specific techniques to induce duodenogastric reflux. Methods: One hundred and twenty Wistar rats were divided into three groups: Group I (n=40) -gastrotomy; Group II (n=40) - duodenogastric reflux after gastrojejunoanastomosis latero-lateral (DGR); Group III (n=40) - retrograde duodenogastric reflux through the pylorus (DGR-P). The groups were divided into 4 subgroups of 10 animals, respectively treated for 16 weeks with water, omeprazole 1.6 mg / rat / day, nitrite 600 mg / kg / day and omeprazole plus nitrite simultaneously. Results: The proliferative lesions found were: squamous hyperplasia - 69.1%, adenomatous hyperplasia in the anastomosis - 29.1% and prepyloric adenomatous hyperplasia - 42.5%. Adenocarcinomas were registered in 7 animals (5.8%): one in Group I (omeprazole plus nitrite), two in Group II (omeprazole and nitrite plus omeprazole) and four in Group III (water, nitrite, omeprazole and omeprazole plus nitrite). Conclusions: The occurrence of squamous hyperplasia, adenomatous hyperplasia and adenocarcinoma increased after gastrojejunal anastomoses, which cause duodenogastric reflux. The association of omeprazole did not protect the development of proliferative lesions and cancer induced by duodenogastric reflux in rats.(AU)

Omeprazole and adenocarcinoma in the stomach of rats submitted to duodenogastric reflux. Is there a protective effect?

Abstract Purpose: To investigate the role of omeprazole and nitrites on the gastric mucosa of rats submitted to specific techniques to induce duodenogastric reflux. Methods: One hundred and twenty Wistar rats were divided into three groups: Group I (n=40) -gastrotomy; Group II (n=40) - duodenogastric reflux after gastrojejunoanastomosis latero-lateral (DGR); Group III (n=40) - retrograde duodenogastric reflux through the pylorus (DGR-P). The groups were divided into 4 subgroups of 10 animals, respectively treated for 16 weeks with water, omeprazole 1.6 mg / rat / day, nitrite 600 mg / kg / day and omeprazole plus nitrite simultaneously. Results: The proliferative lesions found were: squamous hyperplasia - 69.1%, adenomatous hyperplasia in the anastomosis - 29.1% and prepyloric adenomatous hyperplasia - 42.5%. Adenocarcinomas were registered in 7 animals (5.8%): one in Group I (omeprazole plus nitrite), two in Group II (omeprazole and nitrite plus omeprazole) and four in Group III (water, nitrite, omeprazole and omeprazole plus nitrite). Conclusions: The occurrence of squamous hyperplasia, adenomatous hyperplasia and adenocarcinoma increased after gastrojejunal anastomoses, which cause duodenogastric reflux. The association of omeprazole did not protect the development of proliferative lesions and cancer induced by duodenogastric reflux in rats.

Marcadores de estrés oxidativo en pacientes con esclerosis múltiple durante un brote y su remisión / Oxidative stress markers in patients with multiple sclerosis during an outbreak and its remission / Marcadores de estresse oxidativo em pacientes com esclerose múltipla durante um surto e sua remissão

La esclerosis múltiple remitente-recurrente (EM-RR) es una enfermedad desmielinizante del sistema nervioso central. A fin de entender la asociación del estrés oxidativo a nivel periférico con la recaída de la enfermedad se determinaron los niveles de marcadores de estrés oxidativo en plasma de pacientes en la recaída o brote y una semana después de la misma. Se analizaron muestras de 60 personas (20 pacientes con recaída, 20 pacientes sin recaída y 20 controles sanos). Se cuantificaron mediante métodos espectrofotométricos las actividades enzimáticas de óxido nítrico sintasa (ONS), glutatión peroxidasa (GPx), los niveles de lipoperóxidos y nitritos-nitratos y la fluidez de membrana. En el brote de la enfermedad aumentan significativamente los niveles de las actividades enzimáticas de ONS y GPx y los niveles de nitritos-nitratos y lipoperóxidos (p<0,01 en todos los casos), al ser comparados con los de individuos sanos. Dichos parámetros disminuyeron significativamente una semana después de iniciado el brote. Además, los parámetros evaluados se mantuvieron elevados en pacientes que no experimentaron un brote de la enfermedad cuando se los comparó con individuos sanos. La fluidez de membrana en los pacientes con y sin brote fue similar a la de los controles. En conclusión, el estrés oxidativo es un componente importante en los pacientes con esclerosis múltiple.

Recurrent-remitting multiple sclerosis (RR-MS) is a demyelinating disease of the central nervous system. In order to understand the association of oxidative stress at the peripheral level with the relapse of the disease, the levels of oxidative stress markers in plasma of patients in the relapse or outbreak and one week after relapse were determined. Samples of 60 subjects were analyzed (20 patients in relapse, 20 patients without relapse, and 20 healthy controls). The enzymatic activities of nitric oxide synthase (NOS), glutathione peroxidase (GPx), lipoperoxides and nitrite-nitrate levels and membrane fluidity were quantified by spectrophotometric methods. In relapse, the levels of enzymatic activities of NOS and GPx, and the levels of lipoperoxides and nitrites-nitrates were significantly increased (p<0.01, in all cases), compared with healthy individuals. These parameters decreased significantly 1 week after the start of the outbreak. In addition, the parameters evaluated remained high in patients who did not experience an outbreak of the disease compared to healthy subjects. The membrane fluidity in the patients with and without outbreak was similar to that of the controls. In conclusion, oxidative stress is an important component in patients with multiple sclerosis.

A esclerose múltipla recorrente-remitente (EM-RR) é uma doença desmielinizante do sistema nervoso central. Para compreender a associação do estresse oxidativo a nível periférico com a recaída da doença foram determinados os níveis de marcadores de estresse oxidativo em plasma de doentes na recaída ou surto e uma semana após a recaída. Foram analisadas a amostras de 60 pessoas (20 pacientes com recaída, 20 pacientes sem recaída e 20 controles saudáveis). As atividades enzimáticas de óxido nítrico sintase (ONS), glutationa peroxidase (GPX), os níveis de lipoperóxidos e nitritos-nitratos e a fluidez de membrana foram quantificadas por métodos espectrofotométricos. No surto da doença aumentam em forma significativa os níveis da atividade enzimática de ONS e GPX, e os níveis de nitritos-nitratos e lipoperóxidos (p<0,01 em todos os casos), em comparação com os indivíduos saudáveis. Esses parâmetros diminuíram significativamente uma semana após o início do surto. Além disso, os parâmetros avaliados permaneceram elevados em pacientes que não experimentaram um surto da doença quando comparados com indivíduos saudáveis. A fluência de membrana nos pacientes com e sem surto foi semelhante à dos controles. Em conclusão, o estresse oxidativo é um componente importante nos pacientes com esclerose múltipla.

Effect of melatonin administration on cyclooxygenase-2 activity, serum levels of nitric oxide metabolites, lipoperoxides and glutathione peroxidase activity in patients with Parkinson's disease / Efecto de la administración de melatonina sobre la actividad de la ciclooxigenasa-2, la concentración sérica de metabolitos del óxido nítrico, los lipoperóxidos y la actividad de la glutatión peroxidasa en pacientes con enfermedad de Parkinson.

Objective: To determine the effect of melatonin (MEL) administration on ciclooxigenase 2 (COX-2) activity and serum concentration of nitric oxide metabolites, lipoperoxides and glutathione peroxidase (GPx) activity in patients with Parkinson's disease. Methods: Prospective double-blind randomized clinical pilot trial. 13 patients were included and two groups were formed: MEL at doses of 25 mg orally every 12 hours for 12 months and placebo with corn starch. Patients were assessed using the Unified Parkinson's Disease Scale. A blood sample was taken at baseline and every 3 months until 12 months. Results: COX-2 activity decreased as did nitrates/nitrites (3, 6 and 9 months) and lipoperoxides (9 and 12 months); GPx exhibited no significant differences.

Potential Biomarkers with Plasma Cortisol, Brain-derived Neurotrophic Factor and Nitrites in Patients with Acute Ischemic Stroke.

BACKGROUND: Acute Ischemic Stroke (AIS) represents an economic challenge for health systems all over the globe. Changes of neuroactive steroids have been found in different neurological diseases. We have previously demonstrated that old patients with AIS show changes of plasma cortisol and estradiol concentrations, in that increased steroid levels are associated with a deterioration of neurological status and a worse cognitive decline. OBJECTIVE: The present study assessed in patients with AIS if changes of behavior, Brain-Derived Neurotrophic Factor (BDNF) and Nitrites (NO-2) bear a relationship with the degree of hypercortisolism. METHODS: We recruited patients hospitalized within the first 24 hours of AIS. Subjects were divided into two groups, each one composed of 40 control subjects and 40 AIS patients, including men and women. The neurological condition was assessed using the National Institute of Health Stroke Scale (NIHSS) and the cognitive status with the Montreal Cognitive Assessment (MoCA). The emotional status was evaluated using the Montgomery-Asberg Depression Rating Scale (MADRS), whereas the Modified Rankin Scale (MRS) was used to determine the functional condition. BDNF and NO-2 plasma levels were measured by ELISA and the Griess reaction method, respectively. RESULTS: We found that in AIS patients, increased plasma cortisol was negatively correlated with plasma BDNF and NO-2 levels, neurological condition, cognition, functional responses and emotional status, suggesting a relationship between the declines of clinical, behavioral and blood parameters with stress-induced cortisol elevation. CONCLUSION: Nitrites and BDNF may represent potential biomarkers for cortisol negative effects on the area of cerebral ischemia and penumbra, potentiating ischemic cell damage.

Metahemoglobinemia relacionada con ingesta de puré de acelgas / Methemoglobinemia due to ingestion of chard puree

La metahemoglobinemia es un síndrome clínico dado por la presencia de una forma aberrante de hemoglobina, ocasionada por diversos agentes oxidantes. Se describe un caso clínico de metahemoglobinemia severa asociada a la ingesta de puré de acelgas con alto contenido en nitratos y nitritos. Paciente de un año, con antecedentes de comunicación interauricular (CIA), que presentó un cambio en coloración de la piel 7 h antes, en forma progresiva, acompañado de vómitos. Ingresó al Departamento de Emergencia con cianosis generalizada que no mejoró con oxigenoterapia, taquicardia y tendencia a hipotensión arterial. En cuidados intensivos se realizó ecocardiograma que evidenció CIA sin repercusión hemodinámica. Metahemoglobinemia 37%. Se realizó dosis de azul de metileno al 1% por vía intravenosa, con franca mejoría clínica a la hora de la administración del antídoto y descenso de niveles de metahemoglobina. Alta médica a las 36 horas del ingreso. Existía una relación cronológica entre la exposición a nitratos por ingesta de un puré de acelgas y la aparición del cuadro. Los niveles de nitratos hallados en dicho alimento fueron muy elevados considerando estándares internacionales, lo que sumado a una inadecuada conservación del alimento cocido los días previos, permitió confirmar el planteo etiológico realizado. Resulta importante sospechar esta entidad patológica poco frecuente frente a cianosis que no mejora con oxígeno, y prevenir cuadros similares al descrito mediante una adecuada manipulación y conservación de las verduras con alto contenido en nitratos.

Metahemoglobinemia relacionada con ingesta de puré de acelgas / Methemoglobinemia due to ingestion of chard puree

La metahemoglobinemia es un síndrome clínico dado por la presencia de una forma aberrante de hemoglobina, ocasionada por diversos agentes oxidantes. Se describe un caso clínico de metahemoglobinemia severa asociada a la ingesta de puré de acelgas con alto contenido en nitratos y nitritos. Paciente de un año, con antecedentes de comunicación interauricular (CIA), que presentó un cambio en coloración de la piel 7 h antes, en forma progresiva, acompañado de vómitos. Ingresó al Departamento de Emergencia con cianosis generalizada que no mejoró con oxigenoterapia, taquicardia y tendencia a hipotensión arterial. En cuidados intensivos se realizó ecocardiograma que evidenció CIA sin repercusión hemodinámica. Metahemoglobinemia 37%. Se realizó dosis de azul de metileno al 1% por vía intravenosa, con franca mejoría clínica a la hora de la administración del antídoto y descenso de niveles de metahemoglobina. Alta médica a las 36 horas del ingreso. Existía una relación cronológica entre la exposición a nitratos por ingesta de un puré de acelgas y la aparición del cuadro. Los niveles de nitratos hallados en dicho alimento fueron muy elevados considerando estándares internacionales, lo que sumado a una inadecuada conservación del alimento cocido los días previos, permitió confirmar el planteo etiológico realizado. Resulta importante sospechar esta entidad patológica poco frecuente frente a cianosis que no mejora con oxígeno, y prevenir cuadros similares al descrito mediante una adecuada manipulación y conservación de las verduras con alto contenido en nitratos.

Methemoglobinemia is a clinical syndrome due to the presence of an aberrant form of hemoglobin, caused by various oxidizing agents. The study reports a case of severe methemoglobinemia associated with the ingestion of chard puree with high levels of nitrates and nitrites. A 1-year-old patient with a history of atrial septal defect (ASD), who progressively showed change of skin color 7 hours earlier, accompanied by vomiting. She was admitted to the Emergency Department with generalized cyanosis not improving with oxygen therapy, tachycardia and tendency to hypotension. In the intensive care unit, an echocardiogram showed ASD without hemodynamic complications. Methemoglobinemia 37%. A 1% methylene blue dose was administered intravenously, with clinical improvement one hour after antidote administration and decrease in methemoglobin levels. Medical discharge at 36 hours of admission. There was a chronological relationship between nitrates exposure by ingestion of chard puree and the clinical onset of methemoglobinemia. The toxic cause was confirmed after high nitrates levels were found in this vegetable considering international standards, and an inadequate preservation of the cooked chard on previous days. It is important to suspect this rare pathological entity when cyanosis fails to improve with oxygen, and to prevent poisonings similar to those described by an adequate manipulation and preservation of vegetables with high nitrate levels.

Performance of the dipstick screening test as a predictor of negative urine culture / Desempenho da fita de urina como resultado presuntivo para cultura de urina negativa

ABSTRACT Objective To investigate whether the urine dipstick screening test can be used to predict urine culture results. Methods A retrospective study conducted between January and December 2014 based on data from 8,587 patients with a medical order for urine dipstick test, urine sediment analysis and urine culture. Sensitivity, specificity, positive and negative predictive values were determined and ROC curve analysis was performed. Results The percentage of positive cultures was 17.5%. Nitrite had 28% sensitivity and 99% specificity, with positive and negative predictive values of 89% and 87%, respectively. Leukocyte esterase had 79% sensitivity and 84% specificity, with positive and negative predictive values of 51% and 95%, respectively. The combination of positive nitrite or positive leukocyte esterase tests had 85% sensitivity and 84% specificity, with positive and negative predictive values of 53% and 96%, respectively. Positive urinary sediment (more than ten leukocytes per microliter) had 92% sensitivity and 71% specificity, with positive and negative predictive values of 40% and 98%, respectively. The combination of nitrite positive test and positive urinary sediment had 82% sensitivity and 99% specificity, with positive and negative predictive values of 91% and 98%, respectively. The combination of nitrite or leukocyte esterase positive tests and positive urinary sediment had the highest sensitivity (94%) and specificity (84%), with positive and negative predictive values of 58% and 99%, respectively. Based on ROC curve analysis, the best indicator of positive urine culture was the combination of positives leukocyte esterase or nitrite tests and positive urinary sediment, followed by positives leukocyte and nitrite tests, positive urinary sediment alone, positive leukocyte esterase test alone, positive nitrite test alone and finally association of positives nitrite and urinary sediment (AUC: 0.845, 0.844, 0.817, 0.814, 0.635 and 0.626, respectively). Conclusion A negative urine culture can be predicted by negative dipstick test results. Therefore, this test may be a reliable predictor of negative urine culture.

RESUMO Objetivo Verificar se a triagem de urina por fitas reativas é capaz de predizer a cultura de urina. Métodos Estudo retrospectivo realizado entre janeiro e dezembro de 2014 com 8.587 pacientes, com solicitação médica de triagem de urina (fita), sedimento urinário e cultura de urina. Foram analisados sensibilidade, especificidade, valor preditivo positivo, valor preditivo negativo e curva ROC. Resultados Foram positivas 17,5% das culturas. O nitrito apresentou sensibilidade de 28% e especificidade de 99%. O valor preditivo positivo foi de 89% e o valor preditivo negativo de 87%. Esterase apresentou sensibilidade de 79% e especificidade de 84%. Valor preditivo positivo e valor preditivo negativo foram de 51% e 95%, respectivamente. A combinação de nitrito ou esterase positivos apresentou sensibilidade de 85% e especificidade de 84%. Valor preditivo positivo e valor preditivo negativo foram, respectivamente, 53% e 96%. O sedimento positivo (mais de dez leucócitos por microlitro) apresentou sensibilidade de 92% e especificidade de 71%. O valor preditivo positivo foi 40% e o negativo, 98%. A combinação de nitrito e sedimento urinário positivos apresentou sensibilidade de 82% e especificidade de 99%. Os valores preditivos positivo e negativo foram 91% e 98%, respectivamente. Para o nitrito ou esterase positivos mais os leucócitos positivos, a sensibilidade foi de 94% e a especificidade de 84%. O valor preditivo positivo foi de 58% e o negativo foi de 99%. Com base na curva ROC, o melhor indicador de urocultura positiva foi a associação entre a esterase ou nitrito positivos na fita mais os leucócitos positivos no sedimento, seguido por nitrito e esterase positivos, sedimento urinário positivo isolado, esterase positiva isolada, nitrito positivo isolado e, finalmente, pela associação entre nitrito e sedimento urinário positivos (AUC: 0,845, 0,844, 0,817, 0,814, 0,635 e 0,626, respectivamente). Conclusão Uma urocultura negativa pode ser prevista com resultados negativos na fita. Portanto, este teste pode ser um preditor confiável de urocultura negativa.

Oxidative stress biomarkers and their relationship with cytokine concentrations in overweight/obese pregnant women and their neonates.

BACKGROUND: Oxidative damage present in obese/overweight mothers may lead to further oxidative stress conditions or inflammation in maternal and cord blood samples. Thirty-four pregnant women/newborn pairs were included in this study to assess the presence of oxidative stress biomarkers and their relationship with serum cytokine concentrations. Oxidative stress biomarkers and antioxidant enzymes were compared between the mother/offspring pairs. The presence of 27 cytokines was measured in maternal and cord blood samples. Analyses were initially performed between all mothers and newborns and later between normal weight and mothers with overweight and obesity, and diabetic/non-diabetic women. RESULTS: Significant differences were found in biomarker concentrations between mothers and newborns. Additionally, superoxide-dismutase activity was higher in pre-pregnancy overweight mothers compared to those with normal weight. Activity for this enzyme was higher in neonates born from mothers with normal pregestational weight compared with their mothers. Nitrites in overweight/obese mothers were statistically lower than in their offspring. Maternal free fatty acids, nitrites, carbonylated proteins, malondialdehyde and superoxide dismutase predicted maternal serum concentrations of IL-4, IL-13, IP-10 and MIP-1ß. Arginase activity in maternal plasma was related to decreased concentrations of IL-4 and IL-1ß in cord arterial blood. Increased maternal malondialdehyde plasma was associated with higher levels of IL-6 and IL-7 in the offspring. CONCLUSIONS: Oxidative stress biomarkers differ between mothers and offspring and can predict maternal and newborn cytokine concentrations, indicating a potential role for oxidative stress in foetal metabolic and immunologic programming. Moreover, maternal obesity and diabetes may affect maternal microenvironments, and oxidative stress related to these can have an impact on the placenta and foetal growth.

Effect of exercise intensity on postprandial lipemia, markers of oxidative stress, and endothelial function after a high-fat meal.

The aim of this study was to compare the effects of 2 different exercise intensities on postprandial lipemia, oxidative stress markers, and endothelial function after a high-fat meal (HFM). Eleven young men completed 2-day trials in 3 conditions: rest, moderate-intensity exercise (MI-Exercise) and heavy-intensity exercise (HI-Exercise). Subjects performed an exercise bout or no exercise (Rest) on the evening of day 1. On the morning of day 2, an HFM was provided. Blood was sampled at fasting (0 h) and every hour from 1 to 5 h during the postprandial period for triacylglycerol (TAG), thiobarbituric acid reactive substance (TBARS), and nitrite/nitrate (NOx) concentrations. Flow-mediated dilatation (FMD) was also analyzed. TAG concentrations were reduced in exercise conditions compared with Rest during the postprandial period (P < 0.004). TAG incremental area under the curve (iAUC) was smaller after HI-Exercise compared with Rest (P = 0.012). TBARS concentrations were reduced in MI-Exercise compared with Rest (P < 0.041). FMD was higher in exercise conditions than Rest at 0 h (P < 0.02) and NOx concentrations were enhanced in MI-Exercise compared with Rest at 0 h (P < 0.01). These results suggest that acute exercise can reduce lipemia after an HFM. However, HI-Exercise showed to be more effective in reducing iAUC TAG, which might suggest higher protection against postprandial TAG enhancement. Conversely, MI-Exercise can be beneficial to attenuate the susceptibility of oxidative damage induced by an HFM and to increase endothelial function in the fasted state compared with Rest.

Oral nitrite circumvents antiseptic mouthwash-induced disruption of enterosalivary circuit of nitrate and promotes nitrosation and blood pressure lowering effect.

The nitric oxide (NO•) metabolites nitrite and nitrate exert antihypertensive effects by mechanisms that involve gastric formation of S-nitrosothiols. However, while the use of antiseptic mouthwash (AM) is known to attenuate the responses to nitrate by disrupting its enterosalivary cycle, there is little information about whether AM attenuates the effects of orally administered nitrite. We hypothesized that the antihypertensive effects of orally administered nitrite would not be prevented by AM because, in contrast to oral nitrate, oral nitrite could promote S-nitrosothiols formation in the stomach without intereference by AM. Chronic effects of oral nitrite or nitrate were studied in two-kidney, one-clip (2K1C) hypertensive rats (and normotensive controls) treated with AM (or vehicle) once/day. We found that orally administered nitrite exerts antihypertensive effects that were not affected by AM. This finding contrasts with lack of antihypertensive responses to oral nitrate in 2K1C hypertensive rats treated with AM. Nitrite and nitrate treatments increased plasma nitrites, nitrates, and S-nitrosothiols concentrations. However, while treatment with AM attenuated the increases in plasma nitrite concentrations after both nitrite and nitrate treatments, AM attenuated the increases in S-nitrosothiols in nitrate-treated rats, but not in nitrite-treated rats. Moreover, AM attenuated vascular S-nitrosylation (detected by the SNO-RAC method) after nitrate, but not after nitrite treatment. Significant correlations were found between the hypotensive responses and S-nitrosothiols, and vascular S-nitrosylation levels. These results show for the first time that oral nitrite exerts antihypertensive effects notwithstanding the fact that antiseptic mouthwash disrupts the enterosalivary circulation of nitrate. Our results support a major role for S-nitrosothiols formation resulting in vascular S-nitrosylation as a key mechanism for the antihypertensive effects of both oral nitrite and nitrate.

Effects of Nitrate Intake on Myocardial Ischemia-Reperfusion Injury in Diabetic Rats / Efeitos do Consumo de Nitrato na Lesão de Isquemia-Reperfusão Miocárdica em Ratos Diabéticos

Abstract Background: Coronary artery disease is 2-3 times more common in diabetic individuals. Dietary nitrate/nitrite has beneficial effects in both diabetes and cardiovascular disease. It also has protective effects against myocardial ischemia-reperfusion (IR) injury in healthy animals. However, the effects of nitrate on myocardial IR injury in diabetic rats have not yet been investigated. Objective: We examined the effects of dietary nitrate on myocardial IR injury in streptozotocin-nicotinamide-induced diabetic rats. Method: Rats were divided into four groups (n=7 in each group): control, control+nitrate, diabetes, and diabetes+nitrate. Type 2 diabetes was induced by injection of streptozotocin and nicotinamide. Nitrate (sodium nitrate) was added to drinking water (100 mg/L) for 2 months. The hearts were perfused in a Langendorff apparatus at 2 months and assessed before (baseline) and after myocardial IR for the following parameters: left ventricular developed pressure (LVDP), minimum and maximum rates of pressure change in the left ventricle (±dP/dt), endothelial nitric oxide (NO) synthase (eNOS) and inducible NO synthase (iNOS) mRNA expression, and levels of malondialdehyde (MDA) and NO metabolites (NOx). Results: Recovery of LVDP and ±dP/dt was lower in diabetic rats versus controls, but almost normalized after nitrate intake. Diabetic rats had lower eNOS and higher iNOS expression both at baseline and after IR, and dietary nitrate restored these parameters to normal values after IR. Compared with controls, heart NOx level was lower in diabetic rats at baseline but was higher after IR. Diabetic rats had higher MDA levels both at baseline and after IR, which along with heart NOx levels decreased following nitrate intake. Conclusion: Dietary nitrate in diabetic rats provides cardioprotection against IR injury by regulating eNOS and iNOS expression and inhibiting lipid peroxidation in the heart.

Resumo Fundamentos: A doença arterial coronariana é duas a três vezes mais comum em indivíduos diabéticos. O nitrato/nitrito dietético tem efeitos benéficos tanto para o diabetes quanto para a doença cardiovascular, assim como efeitos protetores contra a lesão de isquemia-reperfusão (IR) miocárdica em animais saudáveis. Porém, os efeitos do nitrato na lesão de IR miocárdica em ratos diabéticos ainda não foram investigados. Objetivos: Foram examinados os efeitos sobre a lesão de IR miocárdica da adição de nitrato à dieta de ratos com diabetes mellitus tipo 2 induzido por estreptozotocina-nicotinamida. Métodos: Os ratos foram divididos em quatro grupos (n = 7 em cada grupo): controle, controle+nitrato, diabetes e diabetes+nitrato. O diabetes foi induzido nos animais por injeção de estreptozotocina e nicotinamida. Nitrato (nitrato de sódio) foi adicionado à água de beber (100 mg/L) por 2 meses. Os corações foram perfundidos em sistema de Langendorff aos 2 meses e avaliados antes (basal) e após IR miocárdica em relação aos seguintes parâmetros: pressão desenvolvida no ventrículo esquerdo (PDVE), taxas máximas de variação positiva e negativa da pressão ventricular esquerda (±dP/dt), expressão do RNAm da óxido nítrico (NO) sintase (NOS) endotelial (eNOS) e da NOS induzível (iNOS), além de níveis de malondialdeído (MDA) e metabólitos do óxido nítrico (NOx). Resultados: A recuperação da PDVE e ±dP/dt foi inferior nos ratos diabéticos versus controles, mas quase normalizou após ingestão de nitrato. Ratos diabéticos apresentaram expressão diminuída de eNOS e aumentada de iNOS tanto no estado basal quanto após IR, e o consumo dietético de nitrato restaurou estes valores para o estado normal após a IR. O nível de NOx cardíaco foi menor nos ratos diabéticos em comparação aos controles no momento basal, mas foi superior após a IR. Ratos diabéticos apresentaram níveis mais elevados de MDA tanto no estado basal quanto após IR que, juntamente com os níveis cardíacos de NOx, reduziram após consumo dietético do nitrato. Conclusões: O consumo dietético de nitrato por ratos diabéticos ofereceu cardioproteção contra a lesão de IR através da regulação da expressão de eNOS e iNOS e inibição da peroxidação lipídica no coração.