The effect of ethylene oxide sterilization on electrospun vascular grafts made from biodegradable polyesters.

The study describes the detailed examination of the effect of ethylene oxide sterilization on electrospun scaffolds constructed from biodegradable polyesters. Different fibrous layers fabricated from polycaprolactone (PCL) and a copolymer consisting of polylactide and polycaprolactone (PLCL) were investigated for the determination of their mechanical properties, degradation rates and interaction with fibroblasts. It was discovered that the sterilization procedure influenced the mechanical properties of the electrospun PLCL copolymer scaffold to the greatest extent. No effect of ethylene oxide sterilization on degradation behavior was observed. However, a delayed fibroblast proliferation rate was noticed with concern to the ethylene oxide sterilized samples compared to the ethanol sterilization of the materials.

Elastic three-dimensional poly (ε-caprolactone) nanofibre scaffold enhances migration, proliferation and osteogenic differentiation of mesenchymal stem cells.

OBJECTIVES: We prepared 3D poly (ε-caprolactone) (PCL) nanofibre scaffolds and tested their use for seeding, proliferation, differentiation and migration of mesenchymal stem cell (MSCs). MATERIALS AND METHODS: 3D nanofibres were prepared using a special collector for common electrospinning; simultaneously, a 2D PCL nanofibre layer was prepared using a classic plain collector. Both scaffolds were seeded with MSCs and biologically tested. MSC adhesion, migration, proliferation and osteogenic differentiation were investigated. RESULTS: The 3D PCL scaffold was characterized by having better biomechanical properties, namely greater elasticity and resistance against stress and strain, thus this scaffold will be able to find broad applications in tissue engineering. Clearly, while nanofibre layers of the 2D scaffold prevented MSCs from migrating through the conformation, cells infiltrated freely through the 3D scaffold. MSC adhesion to the 3D nanofibre PCL layer was also statistically more common than to the 2D scaffold (P < 0.05), and proliferation and viability of MSCs 2 or 3 weeks post-seeding, were also greater on the 3D scaffold. In addition, the 3D PCL scaffold was also characterized by displaying enhanced MSC osteogenic differentiation. CONCLUSIONS: We draw the conclusion that all positive effects observed using the 3D PCL nanofibre scaffold are related to the larger fibre surface area available to the cells. Thus, the proposed 3D structure of the nanofibre layer will find a wide array of applications in tissue engineering and regenerative medicine.

[QT interval dispersion in hypertensive diabetics and in patients with hypertension with chronic heart failure without diabetes]. / Disperzia QT intervalov u hypertonických diabetikov a u pacientov s hypertenziou bez diabetu s chronickým srdcovým zlyhaním.

AIM: Our aim was to: 1. compare QT dispersion from routine ECG in diabetic and no-diabetic patients with congestive heart failure, 2. describe associations between QT dispersion and circadian blood (BP) pressure variation in type 2 diabetic patients with congestive heart failure (CHF). PATIENTS AND METHODS: 122 patients admitted to hospital due to CHF in the period between years 2000-2001 have been divided into 2 groups: group 1:70 patients (m: 40, f: 30, mean age 64.7 +/- 9 years) with type II diabetes mellitus (DM), group 2:52 patients (m: 28, f:24, mean age 62.5 +/- 10.9 years) without DM. Diagnosis of CHF was made clinically and proved by ECG and ECHO (EF < 40%), DM was defined clinically or by using oral glucose tolerance test (75 g glucose, 2 h blood glucose > 11.1 mmol/l). The QT interval was measured from the beginning of the QRS complex to the end of the T wave from routine 12-lead ECG. QT intervals were corrected for heart rate using Bazett's formula. QT dispersion (QTd) and rate corrected QT dispersion (QTc) were defined as the difference between the maximum and minimum QT and QTc intervals, respectively. Ambulatory blood pressure (AMBP) was measured by an oscillometic technique. Diabetic patients with CHF were divided both according to below and above the median QTc dispersion (65 ms). STATISTICAL ANALYSIS: Chi-square and Student's t-test. Significant differences were assumed of p < 0.05. RESULTS: Both groups were matched by gender, age, duration and intensity of hypertension, the presence and intensity of obesity, hyperlipidemia (TC, TG, LDL-C, HDL-C) and smoking habits. Diabetic patients with CHF had significantly longer QTc interval (maximum and minimum), QT dispersion and QTc dispersion compared with non-diabetic patients with CHF. Diabetic patients with CHF with QTc dispersion > 65 ms had significantly higher night systolic (133 +/- 14 vs. 112 +/- 14) and diastolic (80 +/- 11 vs. 65 +/- 6) BP and significantly higher night/day ratio for both systolic (0.94 +/- 0.05 vs. 0.86 +/- 0.06) and diastolic (0.89 +/- 0.07 vs. 0.80 +/- 0.05) compared with diabetic patients with CHF with QTc dispersion < 65 ms. CONCLUSION: Diabetic patients with CHF are higher risk than non-diabetic. Our data describe both factors related to cardiovascular risk in diabetic patients with CHF-prolongation of the QT and QTc dispersion and reduced nocturnal blood pressure.

Is left ventricular hypertrophy a risk factor in hypertensive patients?

BACKGROUND: Left ventricular hypertrophy (LVH) is supposed to be a risk factor of cardiovascular (CV) complications in hypertensive patients. AIM: To compare clinical events in hypertensives with and without LVH. PATIENTS AND METHODS: 319 hypertensives with LVH (mean age 64.1+/-10.6 ys) and 177 hypertensives without LVH (mean age 62.5+/-11.3 ys). LVH defined by echo Penn convention as left ventricular mass index >134 g/m2 in men and >110 g/m2 in women. Clinical events--heart failure (EF<40 %), left ventricular diastolic dysfunction (echo-doppler: transmitral-flow where peak A>peak E), myocardial infarction (history, ECG, cardiac enzymes), chronic atrial fibrillation (more than 2 weeks duration), mitral regurgitation (echo) and renal involvement (creatininemia>120 micromol/l). The two groups of hypertensives were matched by demographic criteria, duration and intensity of hypertension, obesity, diabetes mellitus, lipid serum levels and smoking habits. RESULTS: There were statistically significant at least p<0.05 more CV events (heart failure, left ventricular diastolic dysfunction, myocardial infarction, chronic atrial fibrillation, and mitral regurgitation cases) and renal involvement in LVH-positive patients than in LVH-negative patients. CONCLUSION: LVH is a strong risk factor for clinical events in hypertensives, which necessitates their more intensive treatment, mainly with drugs producing also LVH regression. (Tab. 5, Ref. 48.)

[Heart failure in hypertensive patients with left ventricular hypertrophy]. / Srdcové zlyhanie u hypertonikov s hypertrofiou l'avej komory.

Left ventricular hypertrophy (LVH) is supposed to be a useful marker of cardiovascular complications during the course of hypertension. Authors compared the presence of heart failure, left ventricular diastolic dysfunction and chronic atrial fibrillation in hypertensive patients with and without left ventricular hypertrophy defined by echocardiography. Hospital records of 192 hypertensives treated in our medical department during years 1996-1999 were analysed. Left ventricular hypertrophy was defined by echocardiography (Penn convention) as left ventricular mass index > 134 g/m2 in men and > 110 g/m2 in women. Presence of LVH was found in 128 patients (mean age 65.9 years), absence of LVH in 64 patients (mean age 64.8 years). Both groups of hypertensives were matched by demographic parameters, by the presence of hyperlipidemia, by smoking habits. Hypertensive patients with left ventricular hypertrophy were more often treated by ACE inhibitors. There were statistically significant more patients with heart failure, left ventricular diastolic dysfunction and chronic atrial fibrillation in LVH-positive patients than in LVH-negative once. There was also statistically significant lower ejection fraction (50.3 +/- 11.4% vs 56.5 +/- 7.4%) in LVH-positive patients than in LVH-negative once. Left ventricular hypertrophy in patients with hypertension brings usually a complicated course of the disease with a high contribution to the development of chronic heart failure.

Relation of left ventricular hypertrophy to cardiovascular complications in diabetic hypertensives.

The presence of diabetes mellitus and other risk factors of atherosclerosis, such as obesity, smoking and hyperlipidemia, in hypertensive patients makes the prognosis worse. Authors compared the clinical findings in diabetic hypertensive patients with and without left ventricular hypertrophy, the presence of which was diagnosed and defined by echocardiography. The study is based on the analysis of hospital records of 115 hypertensive patients treated at our department during the period 1998-1999. Left ventricular hypertrophy (LVH) was defined by echocardiography as left ventricular mass index > 134 g/m2 in men and > 110 g/m2 in women. Left ventricular hypertrophy was found in 79 patients (mean age 64.6 ys) but not in 36 patients (mean age 63.3 ys). Both groups were matched as to age and sex, intensity and duration of hypertension and diabetes, obesity, smoking and hyperlipidemia. In LVH-positive patients, there was a statistically significant incidence of heart failure, mitral regurgitation and renal involvement and a more non-significant incidence of left ventricular diastolic dysfunction, myocardial infarction, chronic atrial fibrillation and stroke than in LVH-negative ones. Left ventricular hypertrophy usually complicates the course of hypertension. Authors recommend to investigate the presence of left ventricular hypertrophy in hypertensives as it carries a much more complicated course of the disease. (Tab. 5, Ref. 28.)