Biomedical subjects

Jirí Vítovec

Publications and source records attributed to Jirí Vítovec.

8 recordsLinked to original sources

PubMed2006

Infectivity and pathogenicity of Cryptosporidium andersoni to a novel host, southern multimammate mouse (Mastomys coucha).

The infectivity and pathogenicity of Cryptosporidium andersoni (bovine isolate) for neonatal and adult southern multimammate mice (Mastomys coucha) was studied using transmission experiments. C. andersoni isolate used in this study was not infective for BALB/c mice, but experimental infection proved susceptibility of neonatal and adult M. coucha to the infection. The prepatent period was 20-24 days, the patent period varied between 46 and 59 days. No signs of clinical illness or macroscopic findings were detected in infected animals. Cryptosporidium developmental stages were detected only in the glandular part of the stomach of M. coucha in histological sections stained with Wolbach's modification of Giemsa and using immunofluorecence. Histopathological changes were characterized by dilatation and epithelial metaplasia of infected gastric glands without inflammatory response in the lamina propria. Neonatal M. coucha were more susceptible to C. andersoni infection than adults. M. coucha seems to be a useful laboratory model for study of C. andersoni infection.

Age Factors↗

PubMed2006

Age-related and housing-dependence of Cryptosporidium infection of calves from dairy and beef herds in South Bohemia, Czech Republic.

Data of the prevalence, age-related and housing-dependence of naturally acquired cryptosporidiosis on 11 dairy and 11 beef farms in South Bohemia (Czech Republic) were collected. The farms were visited over four consecutive years (from 2002 to 2005). The prevalence of Cryptosporidium in pre-weaned (animals until second month of age) and post-weaned (animals from the third month of age) calves was determined. A total of 7001 faecal samples were collected, concentrated by Sheather's floatation method and stained by aniline-carbol-methyl violet. All samples were examined by light microscopy. Cryptosporidium parvum and C. andersoni oocysts were differentiated on morphological criteria. Of the 7021 specimens, 1814 (25.8%) were positive for Cryptosporidium oocysts; 561 samples (8%) for C. parvum and 1253 (17.8%) for C. andersoni. Pre-weaned dairy calves had higher infection levels of C. parvum than pre-weaned beef calves. The prevalence of C. parvum ranged from 1.4 to 56.5% on dairy farms. Only three cases of C. parvum oocysts shedding in pre-weaned calves on beef farms were found. Only one case of C. andersoni infection in pre-weaned calves was detected and no infections of C. parvum in post-weaned calves were found. The prevalence of C. andersoni reached 35.5% on dairy farms and 61.7% on beef farms. Calves that were on pasture all year long, had a lower probability of C. andersoni infection than those calves kept in a cowshed during the winter season.

Age Factors↗

PubMed2006

Low-frequency electrical stimulation increases muscle strength and improves blood supply in patients with chronic heart failure.

BACKGROUND: This study was designed to evaluate the effects of low-frequency electrical stimulation (LFES) on muscle strength and blood flow in patients with advanced chronic heart failure (CHF). METHODS AND RESULTS: Patients with CHF (n=15; age 56.5 +/- 5.2 years; New York Heart Association III - IV; ejection fraction 18.7 +/- 3.3%) were examined before and after 6 weeks of LFES (10 Hz) of the quadriceps and calf muscles of both legs (1 h/day, 7 days/week). Dynamometry was performed weekly to determine maximal muscle strength (F(max); N) and isokinetic peak torque (PT(max); Nm); blood flow velocity (BFV) was measured at baseline and after 6 weeks of LFES using pulsed-wave Doppler velocimetry of the right femoral artery. Six weeks of LFES significantly increased F(max) (from 224.5 +/- 96.8 N to 340.0 +/- 99.4 N; p<0.001), and also PT(max) (from 94.5 +/- 41.5 Nm to 135.3 +/- 28.8 Nm; p<0.01). BFV in the femoral artery increased after 6 weeks from 35.7 +/- 15.4 cm/s to 48.2 +/- 18.1 cm/s (p<0.05); BFV values at rest before and after 6 weeks of LFES did not differ significantly. CONCLUSIONS: LFES may improve muscle strength and blood supply, and could be recommended for the treatment of patients with severe CHF.

Biomarkers↗

PubMed2006

Electrical stimulation of skeletal muscles. An alternative to aerobic exercise training in patients with chronic heart failure?

The aim of this study was to investigate whether electrical stimulation of skeletal muscles could represent a rehabilitation alternative for patients with chronic heart failure (CHF). Thirty patients with CHF and NYHA class II-III were randomly assigned to a rehabilitation program using either electrical stimulation of skeletal muscles or bicycle training. Patients in the first group (n = 15) had 8 weeks of home-based low-frequency electrical stimulation (LFES) applied simultaneously to the quadriceps and calf muscles of both legs (1 h/day for 7 days/week); patients in the second group (n = 15) underwent 8 weeks of 40 minute aerobic exercise (3 times a week). After the 8-week period significant increases in several functional parameters were observed in both groups: maximal VO2 uptake (LFES group: from 17.5 +/- 4.4 mL/kg/min to 18.3 +/- 4.2 mL/kg/min, P < 0.05; bicycle group: from 18.1 +/- 3.9 mL/kg/min to 19.3 +/- 4.1 mL/kg/min, P < 0.01), maximal workload (LFES group: from 84.3 +/- 15.2 W to 95.9 +/- 9.8 W, P < 0.05; bicycle group: from 91.2 +/- 13.4 W to 112.9 +/- 10.8 W, P < 0.01), distance walked in 6 minutes (LFES group: from 398 +/- 105 m to 435 +/- 112 m, P < 0.05; bicycle group: from 425 +/- 118 m to 483 +/- 120 m, P < 0.03), and exercise duration (LFES group: from 488 +/- 45 seconds to 568 +/- 120 seconds, P < 0.05; bicycle group: from 510 +/- 90 seconds to 611 +/- 112 seconds, P < 0.03). These results demonstrate that an improvement of exercise capacities can be achieved either by classical exercise training or by home-based electrical stimulation. LFES should be considered as a valuable alternative to classical exercise training in patients with CHF.

Bicycling↗

PubMed2005

Combined right ventricular systolic and diastolic dysfunction represents a strong determinant of poor prognosis in patients with symptomatic heart failure.

BACKGROUND: The presence of right ventricular systolic dysfunction is known to significantly worsen prognosis of patients with heart failure. However, the prognostic impact of right ventricular diastolic dysfunction and of its combination with right ventricular systolic dysfunction and with other prognostic markers has not yet been systematically studied. The aim of this study was to assess the prognostic impact of combined right ventricular systolic and diastolic dysfunction in patients with symptomatic heart failure due to ischemic or idiopathic dilated cardiomyopathy. METHODS: The study included 177 consecutive patients with symptomatic heart failure (mean left ventricular ejection fraction of 23%). All patients underwent clinical and laboratory examination, standard echocardiography completed by Doppler tissue imaging of the tricuspid annular motion, and right-sided heart catheterization. They were followed up for a mean period of 16 months (range, 1-48 months). RESULTS: During the follow-up, there were 28 cardiac-related deaths and 35 non-fatal cardiac events (31 hospitalizations for heart failure decompensation and 4 hospitalizations for malignant arrhythmias requiring the implantation of a cardioverter-defibrillator). The multivariate stepwise Cox regression modeling revealed the right ventricular systolic (represented by the peak systolic tricuspid annular velocity-Sa) and diastolic (represented by the peak early diastolic tricuspid annular velocity-Ea) function to be the independent predictors of event-free survival or survival (p<0.01). The Sa separated better between patients with and without the risk of cardiac events (p<0.05), while the Ea appeared to further distinguish patients with increased risk (those at risk of late event from those at risk of early non-fatal event and early death). The strongest predictive information was obtained by the combination of Sa and Ea creating the Sa/Ea categories. The Sa/Ea I category of patients (Sa>or=10.8 cm s(-1) and Ea>or=8.9 cm s(-1)) had excellent prognosis. On the other hand, the Sa/Ea IV category (Sa<10.8 cm s(-1) and Ea<8.9 cm s(-1)) was found to be at a very high risk of cardiac events (p<0.001 vs. Sa/Ea I). Imbalanced categories of patients (Sa/Ea II and III) with only one component (Sa or Ea) pathologically decreased were at medium risk when assessing event-free survival. However, a significantly better survival (p<0.05) was found in patients with Ea>or=8.9 cm s(-1) (Sa/Ea I and III categories) as compared with those having Ea<8.9 cm s(-1) (Sa/Ea II and IV categories). Thus, in contrast to event-free survival, the survival pattern was determined mainly by the Ea value with only little additional contribution of Sa. CONCLUSIONS: The assessment of right ventricular systolic and diastolic function provides complementary information with a very high power to stratify prognosis of patients with heart failure. The combination of right ventricular systolic and diastolic dysfunction identifies those with a very poor prognosis.

Blood Flow Velocity↗

PubMed2005

Right ventricular dysfunction in chronic heart failure patients.

AIM: To evaluate any differences in haemodynamic and echocardiographic parameters in patients with both left (LV) and right ventricular (RV) systolic dysfunction and in patients with isolated LV systolic dysfunction. STUDY GROUP: One hundred patients with RV systolic dysfunction defined as peak velocity of tricuspid annular motion in systole (Sa)<11.5 cm/s, and 55 patients without RV systolic dysfunction Sa>11.5 cm/s. All patients had LV systolic dysfunction, LV ejection fraction (EF) below 40%, NYHA II-IV. METHODS: LV diameters, volumes and EF were measured by echocardiography. Patients underwent tissue Doppler imaging (TDI) of tricuspid annular motion with measurement of peak systolic velocity (Sa), peak early (Ea) and peak late (Aa) diastolic velocities. Right heart catheterization was also performed. RESULTS: Patients with RV systolic dysfunction did not differ from those without RV systolic dysfunction in terms of LV function. Patients with RV systolic dysfunction had larger RV dimension 30.6+/-5.8 vs. 33.9+/-6.7 mm, p<0.002. The patients with RV systolic dysfunction had higher values on right heart catheterization: MPAP 29.6+/-12.1 vs. 24.9+/-11.4 mm Hg, p<0.02, PCWP 20.8+/-10.0 vs. 17.3+/-9.3 mm Hg, p<0.03, PVR 189.9+/-123.3 vs. 137.7+/-94.9 dyn s cm(-5), p<0.008, CVP 7.7+/-5.6 vs. 5.1+/-3.9 mm Hg, p<0.002. The patients with RV systolic dysfunction had more pronounced diastolic dysfunction measured by TDI: Ea 9.9+/-2.3 vs. 11.4+/-2.5 cm/s, p<0.0001 and Aa 13.1+/-4.0 vs. 16.5+/-4.7 cm/s, p<0.000007. CONCLUSION: Patients with heart failure and both left and right ventricular systolic dysfunction showed more serious findings on central haemodynamics as well as more pronounced right ventricular diastolic dysfunction than those with isolated left ventricular systolic dysfunction.

Female↗

PubMed2004

Heart failure and first dose hypotension after angiotensin converting enzyme inhibitors.

The first-dose induced decrease in blood pressure in some patients following the administration of ACE inhibitors is a fact causing some concern among clinicians prescribing these drugs. However, an overview of clinical trials and the authors' own experience clearly point to the possibility of reducing the incidence and/or severity of first-dose hypotension. Apart from appropriate clinical measures to be taken, the choice of the ACE inhibitor seems to be of crucial importance as some (fosinopril, perindopril) produce less hypotension than others. Thus, with due circumspection, ACE inhibitors can safely retain their position as the cornerstone of the treatment of chronic heart failure.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2003

Two MMP-2 promoter polymorphisms (-790T/G and -735C/T) in chronic heart failure.

Remodelling of extracellular matrix by activated matrix metalloproteinases is considered to contribute to progression of ventricle remodelling during chronic heart failure. The aim of this study was to associate two promoter polymorphisms, -790T/G and -735C/T, in the gene for matrix metalloproteinase (MMP)-2 (gelatinase A) with chronic heart failure (CHF). For this purpose, 164 patients (124 men, 40 women, median age 56 years, range 21-91 years) with CHF (functional class NYHA II-IV, ejection fraction median 25%, cardiothoracic index more than 50%) were compared with 196 control subjects without clinical signs of cardiovascular disease (131 men and 65 women, median age 56 years, range 27-84 years) in -790T/G and -735C/T MMP-2 genotype distributions and allelic frequencies. The genotypes were determined by polymerase chain reaction (PCR) with restriction analyses. A significant increase of the T allele of the -790T/G MMP-2 polymorphism (p = 0.04), as well as of the C allele of the -735C/T MMP-2 gene polymorphism, in patients with CHF was proven (p = 0.04). The heterozygote CT of the -735C/T MMP-2 polymorphism exhibits a 7 times higher odds ratio (OR) for the CHF patients with lower levels of total cholesterol (less than 5 mmol/l), especially for non-hypertensive CHF men (OR = 7.28, 95% confidence interval 1.51-35.03, p = 0.006). Determination of MMP polymorphisms in the regulatory area of the gene could help us to comprehend individual susceptibility of patients with CHF to MMP inhibitors based on known risks of MMP genotypes.

Adult↗