Biomedical subjects

Ivan B Yanev

Publications and source records attributed to Ivan B Yanev.

5 recordsLinked to original sources

PubMed2005

Time course and progression of pressure overload-induced cardiac hypertrophy in rats.

AIM: To study the time course and progression of pressure overload-induced left ventricular hypertrophy METHODS: Left ventricular hypertrophy was induced in rats by abdominal aorta constriction and assessed at different time points (10, 15, 20, 25, 35, and 45 days) after operation. RESULTS: The cardiac index (the ratio of heart weight to body weight) in aortic-banded animals was characterised by phasic changes when compared with the sham operated and the control animals. In aortic-banded rats the cardiac index rose sharply at days 10 and 15 after operation. This sharp increase was followed by a phase of slight increase (day 20), and then it again sharply increased (day 25). At the remaining time points (days 35 and 45) the cardiac index was significantly increased in comparison with that of the sham operated and the control animals but the increase diminished gradually. CONCLUSION: Our results suggest that left ventricular hypertrophy develops not in a linear but in a phasic way. Yet, the experimental model we used produced a relatively stable left ventricular hypertrophy.

Analysis of Variance↗

PubMed2005

Interleukin-6, interleukin-8, interleukin-10, and C-reactive protein in febrile neutropenia in children with malignant diseases.

AIM: To compare serum levels of interleukin-6, interleukin-8 and interleukin-10 in bacteremic and non-bacteremic episodes of febrile neutropenia in children with malignant diseases, and determine their changes and correlation with C-reactive protein (CRP). MATERIAL AND METHODS: Between January 2003 and June 2004, we examined 41 episodes of febrile neutropenia in 24 children with malignant diseases who were receiving polychemotherapy. C-reactive protein was measured at the onset of febrile episodes and on days 3 and 5 from beginning of therapy. The soluble interleukins-6, -8, and -10 were determined in the serum using enzyme bound immunosorbent analysis at the onset of fever and at 24 and 72 hours after initiation of an empiric antibiotic therapy. RESULTS: The CRP baseline levels differentiated the patients with unexplained fever from those with local infection but did not differentiate them from those with bacteremia. Interleukin-8 at 24 hours differentiated bacteremic from non-bacteremic episodes (P < 0.05) and at a cut-off value of 130 pg/ml it had a sensitivity of 72% and a specificity of 84% to differentiate bacteremia. Interleukin-10 at 24 hours yielded higher values in Gram (-) bacteremia in comparison with the non-bacteremic episodes (P < 0.001) and Gram (+) bacteremia (P < 0.05). Interleukin-6 at 24 hours had significantly higher values in febrile episodes of more than 3 days duration (P < 0.05). CONCLUSIONS: Interleukin-8 could differentiate in the first 24 hours bacteremic from non-bacteremic episodes in febrile neutropenia, while interleukin-10 is perhaps a more accurate marker for Gram (-) bacteremia.

Adolescent↗

PubMed2004

Long-term changes in dyspnea, lung function, and exercise capacity in COPD patients.

OBJECTIVE: To examine longitudinal changes in dyspnea, lung function, and exercise capacity in COPD patients and to compare baseline data of frequent and infrequent exacerbators at trial entry. METHODS: Nineteen stable COPD patients without significant co-morbidity (age, 58.4 +/- 8.4 years; FEV1% = 33 +/- 12%; mean +/- SD) participated in the study. After a mean period of 36 months (range = 24 - 49) the patients were retested using an identical protocol. RESULTS: Repeated measures analysis showed that there was significant deterioration of FEV1 L (from 1.028 +/- 0.349 to 0.928 +/- 0.307; p = 0.007), PImax cm H2O (from 61.9 +/- 24.2 to 42.0 +/- 22.1; p = 0.007), PaO2 mm Hg (from 69.0 +/- 8.6 to 60.1 +/- 6.8; p = 0.003), PaCO2 mm Hg (from 43.1 +/- 4.9 to 47.3 +/- 4.5; p = 0.001), ATS (from 2.4 +/- 1.0 to 2.8 +/- 0.8; p = 0.031), and 6MWD m (from 389 +/- 130 to 341 +/- 135; p = 0.014). There were also changes in IC, T(L,CO)/V(A), PAP and Borg, but they were not statistically significant. Differentiation of patients by frequency of exacerbations per year of observation (> 2 < or =) discriminated them with respect to functional parameters (FEV1, FVC, IC), dyspneic indices (ATS, VAS and Borg) and exercise capacity (6MWD) at the time of enrollment. CONCLUSIONS: 1) Lung function parameters, blood-gas and dyspneic indices, and exercise capacity decline over a mean period of 36 month in patients with COPD; 2) Patients with frequent exacerbations experience more dyspnea and have lower levels of lung function and exercise capacity at trial entry.

Disease Progression↗

PubMed2004

Tidal breathing analysis in school-age children. Comparison with the parameters of forced expiration.

UNLABELLED: Tidal breathing analysis is a method which has the potential to be used for distinguishing and follow-up of airflow obstruction (AFO) in infants, children and critically ill patients. The aim of the present study was to analyse the tidal breathing parameters (TBP) in healthy and in asthmatic school-age children and to compare them with the parameters of forced expiration. SUBJECTS: Two hundred and twenty five healthy children and 100 asthmatics (7 to 14 years- old) took part in the present study. RESULTS: The results show that TBPs exhibit great inter- and intraindividual variability, even if the mean value of 10 consecutive breathing cycles is used. Parameters that reflect the tidal expiratory flow pattern--V(PTEF)/V(E) and T(PTEF)/T(E) demonstrate high variability and no correlation with age, sex and anthropometric parameters in healthy children. These indices are useful for detection of acute changes in bronchomotor tonus in asthmatics - V(PTEF)/V(E) = 36.1 +/- 6.6% vs. 32.6 +/- 6.2% (methacholine) vs. 37.4 +/- 7.5% (salbutamol) and T(PTEF)/T(E) = 34.2 +/- 6.2% vs. 28.6 +/- 7.8% vs. 35.3 +/- 7.5%, resp. (P < 0.05 everywhere; n = 34) as well as for discriminating a group of subjects with AFO vs. controls (V(PTEF)/V(E) = 30.9 +/- 6.5% vs. 35.3 +/- 8.0%; P = 0.005, and T(PTEF)/T(E) = 29.0 +/- 6.7% vs. 32.8 +/- 7.6%; P = 0.016). The evaluation of the area under the ROC curves (AUC) in the asthmatic group showed weak discriminative capacity of T(PTEF)/T(E) and V(PTEF)/V(E) in comparison to FEV1 (AUC of T(PTEF)/T(E) = 0.62; 95%CI 0.51-0.74). CONCLUSIONS: Tidal breathing parameters could add insight t.o the functional profile but are not capable of substituting forced expiration regarding detection of overt airflow obstruction in school-age children.

Adolescent↗

PubMed2004

A reproducible model of cardiac hypertrophy in rats. Problems and obstacles we faced.

AIM: To develop a reproducible model of significant left ventricular hypertrophy in order to study the role played by the tumor suppressor protein 53 (P53) in the mechanisms of cardiac hypertrophy, the cross-talk with the other factors and the connection between expression and activity of P53, cardiac myocyte apoptosis and heart hypertrophy; to discuss the problems and obstacles we faced. METHODS: Male Wistar rats were used in the experiments. Left ventricular hypertrophy was induced by banding the abdominal aorta. Three series of the experiment were performed differing in the place of banding and the size of constriction in order to find the most suitable model for our further research. RESULTS: Forty five days after banding the abdominal aorta just below the diaphragm the cardiac index increased by 30% in comparison with that in the controls. CONCLUSION: We have developed a reproducible model of significant left ventricular hypertrophy in rats. The main advantages of the model are: a) it is technically simple; b) it may be realised in any laboratory all over the world; c) it allows the most common lab animals (male Wistar rats) to be used for studies without having to be subjected to thoracotomy and hence requiring a long recovery period.

Animals↗