Oxidative stress and mitochondrial dysfunction play a role in myelodysplastic syndrome development, diagnosis, and prognosis: A pilot study.

The imbalance between reactive oxygen species (ROS) production and their elimination by antioxidants leads to oxidative stress. Depending on their concentration, ROS can trigger apoptosis or stimulate cell proliferation. We hypothesized that oxidative stress and mitochondrial dysfunction may participate not only in apoptosis detected in some myelodysplastic syndrome (MDS) patients, but also in increasing proliferation in other patients. We investigated the involvement of oxidative stress and mitochondrial dysfunction in MDS pathogenesis, as well as assessed their diagnostic and prognostic values. Intracellular peroxides, superoxide, superoxide/peroxides ratio, reduced glutathione (GSH), and mitochondrial membrane potential (Δψ(mit)) levels were analyzed in bone marrow cells from 27 MDS patients and 12 controls, by flow cytometry. We observed that all bone marrow cell types from MDS patients had increased intracellular peroxide levels and decreased GSH content, compared with control cells. Moreover, oxidative stress levels were MDS subtype- and risk group-dependent. Low-risk patients had the highest ROS levels, which can be related with their high apoptosis; and intermediate-2-risk patients had high Δψ(mit) that may be associated with their proliferative potential. GSH levels were negatively correlated with transfusion dependency, and peroxide levels were positively correlated with serum ferritin level. GSH content proved to be an accurate parameter to discriminate patients from controls. Finally, patients with high ROS or low GSH levels, as well as high superoxide/peroxides ratio had lower overall survival. Our results suggest that oxidative stress and mitochondrial dysfunction are involved in MDS development, and that oxidative stress parameters may constitute novel diagnosis and/or prognosis biomarkers for MDS.

Oxygen therapy multicentric study--a nationwide audit to oxygen therapy procedures in internal medicine wards.

Oxygen therapy is a common and important treatment in Internal Medicine wards, however, several studies report that it isn't provided accordingly with the best of care. The goal of this work is to evaluate oxygen therapy procedures in Portuguese Internal Medicine wards, comparing them to the standards established by the British Thoracic Society (BTS) in its consensus statement "BTS guideline for emergency oxygen use in adult patients". Between September 3rd and 23rd 2010, each one of the 24 enrolled hospitals audited the oxygen therapy procedures for one randomly chosen day. All Internal Medicine inpatients under oxygen therapy or with oxygen prescription were included. Data was collected regarding oxygen prescription, administration and monitoring. Of the 1549 inpatients, 773 met inclusion criteria. There was an oxygen prescription in 93,4%. Most prescriptions were by a fixed dose (82,4%), but only 11,6% of those stated all the required parameters. Absence of oxygen therapy duration and monitoring were the most frequent errors. Oxygen was administered to only 77,0% of the patients with fixed dose prescriptions. FiO(2) or flow rate and the delivery device were the same as prescribed in 70,9 and 89,2% of the patients, respectively. Out of the 127 patients with oxygen therapy prescriptions by target SatO(2) range, 82,7% were on the prescribed SatO(2) objective range. Several errors were found in oxygen therapy procedures, particularly regarding fixed dose prescriptions, jeopardizing the patients. Although recommended by BTS, oxygen therapy prescriptions by target SatO(2) range are still a minority.