Acute but not chronic metabolic acidosis potentiates the acetylcholine-induced reduction in blood pressure: an endothelium-dependent effect

Metabolic acidosis has profound effects on vascular tone. This study investigated the in vivo effects of acute metabolic acidosis (AMA) and chronic metabolic acidosis (CMA) on hemodynamic parameters and endothelial function. CMA was induced by ad libitum intake of 1% NH4Cl for 7 days, and AMA was induced by a 3-h infusion of 6 M NH4Cl (1 mL/kg, diluted 1:10). Phenylephrine (Phe) and acetylcholine (Ach) dose-response curves were performed by venous infusion with simultaneous venous and arterial blood pressure monitoring. Plasma nitrite/nitrate (NOx) was measured by chemiluminescence. The CMA group had a blood pH of 7.15±0.03, which was associated with reduced bicarbonate (13.8±0.98 mmol/L) and no change in the partial pressure of arterial carbon dioxide (PaCO2). The AMA group had a pH of 7.20±0.01, which was associated with decreases in bicarbonate (10.8±0.54 mmol/L) and PaCO2 (47.8±2.54 to 23.2±0.74 mmHg) and accompanied by hyperventilation. Phe or ACh infusion did not affect arterial or venous blood pressure in the CMA group. However, the ACh infusion decreased the arterial blood pressure (ΔBP: -28.0±2.35 mm Hg [AMA] to -4.5±2.89 mmHg [control]) in the AMA group. Plasma NOx was normal after CMA but increased after AMA (25.3±0.88 to 31.3±0.54 μM). These results indicate that AMA, but not CMA, potentiated the Ach-induced decrease in blood pressure and led to an increase in plasma NOx, reinforcing the effect of pH imbalance on vascular tone and blood pressure control.

Levantamento sobre o uso de plantas medicinais com a terapêutica anticâncer por pacientes da Unidade Oncológica de Anápolis / Survey on medicinal plants used with anticancer therapy by patients from Anapolis Oncology Unit

Este estudo teve por objetivo conhecer o perfil dos pacientes em tratamento contra o câncer da Unidade Oncológica de Anápolis quanto ao uso de plantas medicinais. Foram entrevistados 59 pacientes (42,12% da população estudada) por meio de questionários avaliativos enfatizando características sócio-demográficas e dados referentes à utilização de plantas medicinais. Evidenciou-se o uso indiscriminado de plantas medicinais entre os pacientes. A maioria dos entrevistados compartilha a opinião errônea de que plantas medicinais não fazem mal. A orientação sobre a forma de utilização das plantas ocorre, principalmente, pela informação de familiares ou amigos, e os profissionais da saúde muitas vezes são ignorados neste processo. Constatou-se que as plantas medicinais são utilizadas para o tratamento de enfermidades de baixa a alta gravidade, como o câncer. Dentre as 14 espécies usadas pelos pacientes com finalidade antineoplásica as mais mencionadas foram as popularmente conhecidas como noni, babosa, graviola e romã. Apesar de alguns estudos relatarem atividade antineoplásica ou quimiopreventiva para algumas espécies vegetais, muitas delas podem ser tóxicas ou apresentar potencial risco quando usadas concomitantemente ao tratamento convencional. Desta forma, observa-se que é preciso mais profissionais especializados para orientação sobre o risco de reações adversas e interações medicamentosas no que se refere ao uso de espécies vegetais e a terapêutica do câncer.

This study aims to survey the profile ofcancer patients in the Oncology Unit of Anápolis in relation to the use of medicinal plants. To evaluate socio-demographic characteristics and to retrieve data about on the use of medicinal plants, a questionnaire was filled by 59 patients, or 42.12% of the population under study. A widespread use of plants was found. Most of patients share the wrong idea that medicinal plants are not harmful. Guidance on the use of medicinal plants is given primarily by relatives and friends, and health professional are often ignored in this process. Among the 14 species used by patients with antineoplastic purpose, the most mentioned were popularly species known as "noni", "aloe", "soursop" and "pomegranate". Although some studies have reported chemopreventive or antineoplastic activity for some plant species, many may be toxic or show potential risk when used concurrently with conventional treatment. Thus, we can observe that there is a need for more specialized professionals for the guidance on the risk of adverse reactions and drug interactions in relation to the use of plant species and cancer therapeutics.