Atomic force microscopy is a common technique used to determine the elastic properties of living cells. It furnishes the relative Young's modulus, which is typically determined for indentation depths within the range 300-500 nm. Here, we present the results of depth-sensing analysis of the mechanical properties of living fibroblasts measured under physiological conditions. Distributions of the Young's moduli were obtained for all studied cells and for every cell. The results show that for small indentation depths, histograms of the relative values of the Young's modulus described the regions rich in the network of actin filaments. For large indentation depths, the overall stiffness of a whole cell was obtained, which was accompanied by a decrease of the modulus value. In conclusion, the results enable us to describe the non-homogeneity of the cell cytoskeleton, particularly, its contribution linked to actin filaments located beneath the cell membrane. Preliminary results showing a potential application to improve the detection of cancerous cells, have been presented for melanoma cell lines.

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In spite of the extensive research efforts that have been conducted over the last decades, it is still very difficult to point out genetic determinants or environmental conditions responsible for the development of essential hypertension. We searched for differences in the RBC membrane skeleton structure and O2 membrane permeability between RBCs from patients with both essential arterial hypertension and hypercholesterolemia, from patients having only hypercholesterolemia and from healthy donors. The topography of RBCs and the content of various hemoglobin forms were detected using atomic force microscopy and Mössbauer spectroscopy, respectively. We found that the membrane skeleton of RBCs from healthy donors displayed a well-known honeycomb pattern, whereas in patients with essential hypertension and/or hypercholesterolemia, who had never received anti-hypertensive therapy, it displayed a corncob pattern. Hypertensive RBCs had an oval shape and the average lateral to longitudinal diameter ratio for the changed cells (about 70%) did not exceed 0.80. We observed that after the incubation of RBCs under high nitrogen (low O2) pressure at room temperature and then their transfer into 85 K, a content of oxyHb (deoxyHbOH) already after 1 h reached a stable level of about 85 ± 3% (15 ± 3%) in hypertensives, whereas in healthy individuals it showed a decrease for deoxyHbOH and an increase for oxyHb, which stabilized at a level of about 81 ± 5% and 19 ± 5%, respectively, only after 9 h. Quantitative analysis of the Δ(oxyHb) change estimated as the difference between the oxyHb level measured after 9 and 2 h at 85 K under low N2 pressure (to slow down oxyHb formation) was significantly higher in normotensives than in hypertensive patients with or without hypercholesterolemia, 19.9 versus -4.2, p < 0.02. Our findings indicate an impaired oxygen release by Hb in RBCs of patients with hypertension under low oxygen pressure which if present in vivo may cause hypoxemia and, in turn, further increase of blood pressure.

Rheological properties of erythrocytes from patients with high risk of cardiovascular disease (CVD) were analyzed in relation to individual patient risk factors as well as to the medication. Additionally, comparative statistical analysis was performed considering plasma concentration of the selected mediators of vascular endothelium: 6-keto-prostaglandin F 1α (PGF 1α ), sVCAM-1 and E-selectin adhesion molecules and interleukin-6 (IL-6). It was found that antihypertensive therapy with angiotensin-converting enzyme inhibitor (ACEI) is accompanied by improvement of RBC rheology: the increase of deformability and the decrease of aggregability. This improvement is probably mediated by endothelial prostacyclin and nitric oxide which are generated by ACEI. A correlation was observed between RBC deformability/aggregability and the patient's hematocrit level, what implicates that the hematocrit level should be explicitly taken into consideration when investigating rheological properties of erythrocytes. A strong relationship was also found between the plasma concentration of sVCAM-1 and patient's age.

BACKGROUND The EUROACTION study (nurse-coordinated multidisciplinary, family-based cardiovascular disease prevention program) documented the efficacy of a nurse-managed, comprehensive prevention program in reducing risk factors for cardiovascular disease (CVD). No information was available on survival. AIMS The aim of the study was to assess the effects of EUROACTION intervention on CVD risk factors and 12-year survival in the Polish component of the study. METHODS Two district hospitals and 2 primary care practices were allocated randomly to intervention (INT) or usual care (UC). The primary endpoints were lifestyle and risk factors changes at 1-year followup. Differences in survival were analyzed using the multivariable Cox proportional hazards regression models. RESULTS The study involved 628 patients with coronary heart disease (CHD) and 711 high-risk patients. Compared to UC, INT patients achieved healthier lifestyles and a larger reduction of risk factors at 1 year but these differences were not maintained 12 years after the intervention. Less deaths occurred in patients from the INT hospital and from INT primary practice (hazard ratio [HR], 0.58; 95% CI, 0.42-0.82 and HR, 0.53; 95% CI, 0.3-0.95, respectively). Adjustment for the covariates slightly attenuated the estimates and removed significance (HR, 0.74; 95% CI, 0.52-1.04 and HR, 0.66; 95% CI, 0.36-1.24, respectively). For combined CHD and high-risk patient groups, compared with UC, INT patients had a 36% lower risk of death after adjustment for age, sex, and history of CHD (HR, 0.64; 95% CI, 0.48-0.86). CONCLUSIONS The impact of the EUROACTION intervention on lifestyle and CVD risk factors could have contributed to lower mortality in INT coronary and high-risk patients. These results emphasize the need for sustaining the interventions to help patients maintain a healthy lifestyle.

We studied the influence of low doses of γ radiation (from 0.04 to 1.8 mGy) on the stability of human red blood cells (RBC) from healthy donors and diabetic patients using absorption spectroscopy. Because of the alteration of many enzymatic pathways in diabetic RBCs resulting in strong modification of the lipid and protein membrane components one could expect that the ionizing γ-radiation should influence the stability of the healthy and diabetic cells in a different way. Indeed, distinct discontinuities and monotonic changes of hemolysis detected in the healthy and diabetic RBCs suggest that various enzymatic and chemical processes are activated in these membranes by γ radiation. Mössbauer measurements showed that only the highest applied dose of γ radiation caused modification of hemoglobin in both types of RBCs.

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The relationship between erythrocyte deformability and aggregability with left ventricular mass index has been examined in patients diagnosed with at least one cardiovascular risk factor but without ongoing coronary heart disease. The group consisted of 66 individuals, 30 men and 36 women, of the average age 57.7 years. For each patient, deformability and aggregability of red blood cells (RBCs) as well as end-diastolic left ventricle diameter (LVD), interventricular septum thickness (IVST) and posterior wall thickness (PWT) were measured. On the basis of the echocardiographical parameters and anthropometric data, left ventricular mass index (LVMI) was calculated. The analysis revealed statistically significant correlation between the LVMI and erythrocyte deformability and aggregability: the LVMI increases with decreasing deformability and is higher in patients with higher aggregability. This finding indicates that the worsening of RBC rheological properties is one of the main factors contributing to alterations of cardiac geometry through the increase of peripheral resistance which, in turn, significantly augments the heart afterload. Given that left ventricular hypertrophy (LVH) is a predictor of cardiovascular morbidity and mortality, the association between hemorheological parameters and left ventricular geometry may be important in clinical practice.