Flow cytometric assessment of platelet aspirin resistance using light scattering

Effects of High Consumption of Vegetables on Clinical, Immunological, and Antioxidant Markers in Subjects at Risk of Cardiovascular Diseases

High intakes of vegetables have been associated with a lower incidence of cardiovascular diseases (CVD). However, the effect of vegetables on immune function and antioxidant status in human studies have provided contrasting results. In the present study, after a week of run-in period, 38 subjects at risk of CVD were randomly assigned to one of the following 4-week interventions: low vegetable consumption (800 g of vegetables/week) or high vegetable consumption (4200 g of vegetables/week). Vegetables included carrots, topinambur (Jerusalem artichoke, Helianthus tuberosus), tomatoes, red cabbage, and sweet peppers. Blood and salivary samples were collected before and after intervention periods. In addition to clinical, immunological, and antioxidant markers, leukocyte and lymphocyte expression of the gut-homing β7 integrin was evaluated. No significant changes were detected in clinical, immunological, and antioxidant markers in biological samples, except for an increase in white blood cell count for the low vegetable consumption group (p < 0.05). The study provides additional evidence about the uncertainty of providing a clear evidence for vegetables in modulating markers of immune function and antioxidant status. Further studies are needed in order to unravel the mechanism of effect of vegetable consumption in cardiovascular prevention.

Measurement and Clinical Significance of Biomarkers of Oxidative Stress in Humans

Oxidative stress is the result of the imbalance between reactive oxygen species (ROS) formation and enzymatic and nonenzymatic antioxidants. Biomarkers of oxidative stress are relevant in the evaluation of the disease status and of the health-enhancing effects of antioxidants. We aim to discuss the major methodological bias of methods used for the evaluation of oxidative stress in humans. There is a lack of consensus concerning the validation, standardization, and reproducibility of methods for the measurement of the following: (1) ROS in leukocytes and platelets by flow cytometry, (2) markers based on ROS-induced modifications of lipids, DNA, and proteins, (3) enzymatic players of redox status, and (4) total antioxidant capacity of human body fluids. It has been suggested that the bias of each method could be overcome by using indexes of oxidative stress that include more than one marker. However, the choice of the markers considered in the global index should be dictated by the aim of the study and its design, as well as by the clinical relevance in the selected subjects. In conclusion, the clinical significance of biomarkers of oxidative stress in humans must come from a critical analysis of the markers that should give an overall index of redox status in particular conditions.

Flow cytometric detection of erythrocyte osmotic fragility

BACKGROUND

Hereditary spherocytosis (HS) is the most common cause of inherited chronic hemolysis. The various tests developed for HS screening have many shortcomings. The purpose of this study was to develop a new, simple, reliable test using flow cytometry.

METHODS

In this new test, deionized water, a hemolysis-inducing agent, is spiked to a red cell suspension during acquisition, and the count of red cells is measured sequentially in real-time using flow cytometry. In this study, the optimal parameters for this test were established, and the discriminatory power of the adopted protocol was verified among several groups with various degrees of osmotic fragility (OF).

RESULTS

The established protocol successfully discriminated between blood analyzed immediately and blood stored for 24 h (P < 0.00001). With healthy individuals as a reference, the OF measured by this protocol was significantly decreased in patients with iron deficiency anemia (P = 0.030) and was significantly increased in HS patients (P = 1.1 x 10(-9)). This new test found all 11 HS patients to have increased OF.

CONCLUSIONS

This new test was verified to be simple, quantitative, objective, and cost-effective for the measurement of OF. We suggest this test as another effective approach for HS screening, although its assay performance will require further verification through more clinical trials.