Positive effects of naringenin on near-surface membrane fluidity in human erythrocytes.

PURPOSE: Deformability/rheologic behavior of erythrocytes are related to near-surface membrane fluidity. Specific agents can increase erythrocyte membrane fluidity in order to adjust hemodynamics in cardiovascular diseases. Grapefruit flavanone naringenin has been proposed for potential use in an alternative therapy of cardiovascular conditions. In respect to this, we assessed here effects of two nutritionally relevant concentrations of naringenin (0.1 and 1 µg/ml) on near-surface membrane fluidity in human erythrocytes. METHODS: We used electron paramagnetic resonance spectroscopy and fatty acid spin probes (5-DS and 7-DS), the spectra of which are dependent on membrane fluidity. RESULTS: The results showed a significant (p = 0.029) increase of membrane fluidity near the hydrophilic surface in erythrocytes treated with higher concentration of naringenin. In the deeper layer, just below the erythrocyte membrane phospholipid heads, both lower and higher concentration of naringenin significantly increased membrane fluidity (p = 0.036 and p = 0.028, respectively). CONCLUSIONS: These data document the positive and dose dependent effect of naringenin on near-surface membrane fluidity in human erythrocytes, recommending its use in the cardiovascular conditions characterized by disturbed hemodynamics.

Specific binding of paraprotein to platelet receptors as a cause of platelet dysfunction in monoclonal gammopathies.

The study included 48 untreated patients with monoclonal gammopathies (MG). Paraprotein was isolated from the serum of 10 patients with decreased platelet aggregation. Platelet aggregation was measured before and after the addition of the isolated paraprotein to platelet-rich plasma (PRP) from 10 healthy donors, in vitro. Expression of platelet von Willebrand factor (vWF) receptor glycoprotein (GP)Ib and platelet collagen receptor GPVI was determined by flow cytometry in the PRP of healthy donors before and after the addition of isolated paraprotein using the monoclonal antibodies, CD42b (for GPIb) and CD36 (for GPVI). Flowcytometry showed that expression of CD42b and CD36 positive cells was reduced after the addition of isolated paraprotein to PRP from healthy donors (p < 0.001). These investigations demonstrated that paraprotein causes platelet dysfunction in patients with MG due to specific binding to the platelet vWF receptor GPIb and platelet collagen receptor GPVI.

Humoral immunity to cow's milk proteins and gliadin within the etiology of recurrent aphthous ulcers?

OBJECTIVES: The goal of this study was to determine the incidence of serum antibodies to gliadin and to cow's milk proteins (CMP) using ELISA test, within patients who have recurrent aphthous ulcers (RAU). SUBJECTS AND METHODS: Fifty patients with recurrent aphthous ulcers and fifty healthy people were included in this research. Levels of serum IgA and IgG antibodies to gliadin and IgA, IgG and IgE to CMP were determined using ELISA. RESULTS: The levels of serum antigliadin IgA and IgG antibodies were not significantly higher in patients with RAU in comparison with the controls (P = 0.937 and P = 0.1854 respectively). The levels of serum anti-CMP IgA, IgG and IgE antibodies were significantly higher in patients with RAU in comparison with the controls (P < 0.005, P < 0.002 and P < 0.001 respectively). In general, the increased humoral (IgA or IgG) immunoreactivity to CMP was found in 32 of 50 patients, while 17 of them showed the increased levels of both IgA and IgG immunoreactivity to CMP. At the same time, 16 out of 50 patients had IgA, IgG and IgE immunoreactivity to CMP. CONCLUSION: These results indicate the strong association between high levels of serum anti-CMP IgA, IgG and IgE antibodies and clinical manifestations of recurrent aphthous ulcers.