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Biomedical subjects

P Bartůnĕk

Publications and source records attributed to P Bartůnĕk.

At least 19 recordsLinked to original sources
PubMed2005

[Value of duplex ultrasound examination of the proximal part of the common carotid artery].

A significant part of patients with carotid artery stenosis is operated on without preoperative angiography, to reduce the risks and cost of such examination. Duplex ultrasound often cannot reliable visualise the proximal parts of the aortic arch vessels. We evaluated the ability of duplex ultrasound to identify those types of lesions and ascertain their prevalence. We analysed retrospectively carotid duplex scans and carotid angiography in 448 carotid arteries. 17 significant proximal lesions (3.89%) were identified on the duplex scan and confirmed by angiography. Lesions of the proximal parts of the aortic arch vessels are rare and may be reliably detected by duplex ultrasound.

Adult↗
PubMed2005

[Cardiac abnormalities of lyme borreliosis].

The article summarizes basic characteristics of Lyme borreliosis, its incidence, epidemiology, pathogenesis and clinical image. Particular attention is given to the review of papers aimed at the cardiac abnormalities--the Lyme carditis. Though they are not very frequent, due to the variability of their clinical course and due to various forms, which are difficult to diagnose, they can represent a specific problem. Major part of the article is given to the authors' own experience with the dilated cardiomyopathy of the Borrelia origin and namely to the perspective study of the patients after the skin form of the disease erythema migrans, who were treated "lege artis" in the early phase of the disease with antibiotics. Authors were interested how many of those patients would develop later the cardiac abnormalities.

Cardiomyopathy, Dilated↗
PubMed2002

[Prevalence of antiborrelia antibodies in two populations: various interpretations of the same data].

OBJECTIVE: The objective of the work was to test whether differently formulated hypotheses, when using correct statistical methods, and the same data lead to the same results. The work pertains to the interpretation of the prevalence of antiborrelia antibody levels in more or less high risk populations. GROUP: A group of 200 blood donors from Prague (100 men, mean age 33.5 years and 100 women mean age 24.4 years) and 71 subjects with a higher risk of contact with ticks infected with Borrelia burgdorferi--forestry workers from the Sumava mountains (39 men, mean age 40.6 years and 32 women, mean age 44.5 years). METHOD: In all participants antiborrelia antibodies class IgM and IgG were assessed and using the Western blot method the presence of specific antigens was examined. The blood samples of all probands were analyzed in the national reference laboratory for Lyme borreliosis CEM in the National Institute of Public Health in Prague. To test the hypothesis on the difference of groups as regards the frequency of positive antibody levels the chi square test was used. For testing the hypothesis on the difference of the groups as regards antibodies irrespective of normal laboratory values the non-parametric method--the Mann-Whitney test was used. RESULTS: The group of Prague blood donors and forestry workers from the Sumava mountains do not differ as to the individual frequency of positive antibody values assessed by the ELISA method in class IgM and IgG but they differ in class IgM assessed by the Western blot method. Both groups differ moreover markedly in the general distribution of antibodies unrelated to normal laboratory values assessed by the ELISA method in class IgM, in class IgG the distribution does not differ. CONCLUSION: We provided evidence that when using a different formulation of the hypothesis while using correct statistical methods identical data can be differently interpreted. Thus in the interpretation of the prevalence of antiborrelia antibody levels in healthy populations with a different risk--even if the two groups do not differs as to the frequency of positive findings, there is a significant statistical difference in their distribution.

Adult↗
PubMed2001

[Biological weapons--an old menace in new circumstances].

Biological weapons were conceived for years by the world community only as a potential evil. A fundamental change of opinions regarding their real menace occurred only after the premeditated criminal attack on the USA on September 11, 2001. It was logical that publicists for mall types of media demanded from representatives of the state administration of the Czech Republic information how out country is prepared for this type of danger. Their reactions were hesitant and in a way reflect a certain chaos associated with the reorganization of the army and at the same time unpreparedness of civil defence. To a certain extent all this can be conceived as the consequence of the fundamental transformation of our society and thus it may be excused to a certain extent. Nevertheless it is obvious that not even the most advanced countries are quite clear as regards defence against the horror of biological weapons. Evidence to this effect is the following document, devoted to the problem in the USA, major parts of which we reproduce from the prestigious periodical The England Journal of Medicine.

Biological Warfare↗
PubMed2001

[Health risks of mobile phones].

Health problems related to the use of cellular telephones become a "hot" journalistic topic. Incompetent and uninformed authors of newspaper articles inform, deform and sometimes even frighten their users with malignant effects of electromagnetic radiation starting with impairment of psychic concentration, sleep disorders till development brain tumors. Such (and so far not proved apprehensions) have to be confound with scientific arguments. One of the first studies aimed at possibility of brain tumor formation brought about negative answer. The lack of empirical evidences of the mobile phone electromagnetic radiation cancerogenity suggests that cellular phones do not represent a serious risk of cancer.

Brain Neoplasms↗
PubMed2001

Borrelia infection as a cause of carditis (a long-term study).

BACKGROUND: Although the frequency of Lyme carditis is not high, it is one of the most challenging conditions in terms of diagnosis. No long-term studies that would help expand our body of knowledge concerning the circumstances of its development and the natural course of this form of Lyme borreliosis (LB), the most widespread anthropozoonosis in Central Europe, have been reported to date. AIM: The authors sought to describe and assess the consequences of a less common form of Lyme carditis (LC). An assessment of the following aspects was made: a) the forms, natural history and sequelae of the less common clinical appearances of LC, b) the role of antibiotic therapy with reference to the late manifestations of LB. METHODS: Three patients were selected from a group of 60 consecutive patients with demonstrated LC during a follow-up period from 1987 to 2000. Patient no. 1 was being followed for myocarditis with frequent ventricular extrasystoles, patient no. 2 for pericarditis, and patient no. 3 for dilated cardiomyopathy as a late manifestation of LB. In addition to routine examination at entry, the patients were subjected to a standard 12-lead ECG, continuous 24-hour Holter ECG monitoring, exercise testing (bicycle ergometry), investigations of antibodies using ELISA and Western blot, investigation of thyroid (T3, T4, TSH tests) and mineral levels. RESULTS: The study showed no significant correlation between the clinical course and levels of specific antibodies. It confirmed the concept that inadequate or no therapy with antibiotics in the initial stage of the disease has a significant effect on the development of late sequelae. CONCLUSION: Based on the long-term treatment of three patients with less common, yet clinically urgent findings, the authors conclude that even a relatively serious clinical course is associated with no major limitations for affected individuals after an interval of several years.

Adult↗
PubMed2001

The nuclear orphan receptor TR4 promotes proliferation of myeloid progenitor cells.

Nuclear receptors represent key regulators in cell proliferation, differentiation, and development. Here we demonstrate that the nuclear orphan receptor TR4 is highly expressed in hematopoietic cells and tissues and have analyzed the impact of TR4 in this cell compartment. We show that TR4, when ectopically expressed in bone marrow cells via retrovirus vector, promotes proliferation of myeloid progenitor cells. Cells represent promyelocytes as judged by morphological features, expression of cell surface molecules, and specific markers like Mim-1 and CAAT/enhancer binding protein beta. We also demonstrate that the growth promoting activity of TR4 is not exclusively dependent on its association with DNA, because expression of a mutated TR4 version devoid of its DNA binding domain exhibits a similar proliferative potential as wild-type TR4. In conclusion, these data position the orphan receptor TR4 as an important regulator of myeloid progenitor cell proliferation and development.

Acetyltransferases↗
PubMed2000

[Informational value of the prevalence of antiborrelia antibodies in a healthy and at risk population].

The authors tried to confirm data on the prevalence of antiborrelia antibodies class IgM and IgG in the local healthy population (200 blood donors) and in subjects with an increased risk of infection (forestry labourers, forestry workers and huntsmen). All blood samples were analyzed in the National Reference Laboratory for Lyme borreliosis CEM (LB) in the National Institute of Public Health in Prague by the ELISA NRLB KC 90 method and in case of a positive result they were confirmed by the Western blot Lyme method. All patients completed a special questionnaire used as a standard procedure in the consultation centre for LB. In the group of blood donors 100 men were examined, mean age 33.5 years and 100 women, mean age 24.4 years. In 26 positive antibodies against Borrelia burgdorferi (Bb) were confirmed, but on invitation to medical examination only 22 attended, 11 men and 11 women (10.1%). Examination of antiborrelia antibodies by the ELISA method proved positivity of class IgM 7 times and of class IgG 9 times. By the Western blot method (WB) class IgG was confirmed three times. In the risk group 39 men were examined, mean age 40.6 years and 32 women. In 12 of them (17.9%) positivity of antiborrelia antibodies against Borrelia burgdorferi (Bb) was proved by the ELISA method as well as the WB method. If the percentage confidence interval of the control group is taken as a basis for comparison, then the value of the risk group is within this interval at a significance value of alpha = 0.01. In the conclusion the authors discuss the problem of interpretation of positive serological results and the pitfalls of their evaluation not only from the aspect of validity of laboratory findings, due to the absence of standardization of methods, but also with regards to obscure aspects of the persistence of IgM antibodies after years of lege artis antibiotic treatment.

Adolescent↗
PubMed1999

The fibroblast growth factor receptor FGFR-4 acts as a ligand dependent modulator of erythroid cell proliferation.

Receptor and non-receptor tyrosine kinases constitute a large family of proteins that play a pivotal role in hematopoiesis. Here we conducted a comprehensive survey of tyrosine kinase gene expression in primary erythroid progenitor cells from bone marrow by employing a PCR-based strategy that targets the conserved kinase encoding region. We demonstrate that erythroid progenitor cells express several receptor and non-receptor tyrosine kinases, like c-kit, Jak1, Ryk, FAK, Syk, Arg, Csk and members of the insulin receptor family. Specific changes in the expression profile of tyrosine kinases were observed following differentiation induction. We also report on the identification of a new ligand dependent modulator of erythropoiesis, fibroblast growth factor receptor-4 (FGFR-4). FGFR-4 is effectively expressed in erythroid progenitors and downregulated when cells differentiate. Furthermore, the FGFR-4 ligand, basic fibroblast growth factor (bFGF), enhanced erythroid cell proliferation induced by SCF or insulin, and thus modulated both erythroid proliferation and differentiation in vitro.

Animals↗
PubMed1999

[Lyme borreliosis].

The authors present a review of contemporary views on the most frequent anthropozoonosis--Lyme borreliosis. They mention its history, microbiology of the causal agent Borrelia burgdorferi, epidemiology, pathogenesis, laboratory and clinical diagnosis. The authors describe also briefly the clinical stages, forms and possible treatment.

Humans↗
PubMed1999

[Immunization in Lyme borreliosis--initial experience].

The ever increasing rate of new cases of Lyme disease, the tendency for chronicity in certain forms of the disease and especially the disputable effect of causal therapy resulted in strenuous efforts to develop an effective vaccine. The authors sum up recent experience with vaccination in the U.S.A. and Europe. Two studies in the U.S. during the years 1994 through 1997 included more than 20,000 probands. In one of the studies, coordinated by Steer (10,936 probands), during the first year twenty-two people of the vaccinated group contracted the disease compared to forty-three people of the non-vaccinated, i.e. placebo group. The vaccine efficacy was 49 percent. During the second year of the study, after the third dose of the vaccine, sixteen vaccinated people contracted the disease vs. sixty-six placebo probands. Vaccine efficacy was 76 percent. Its administration was accompanied by mild to moderate local or systemic reaction lasting up to three days. In the next study, coordinated by Sigal (10,305 probands) the vaccine efficacy was sixty-eight percent in the first year and ninety-two percent in the second, respectively. Both studies proved the vaccine to be safe and efficient in Lyme disease prevention. In comparison with these large long-term double-blind, placebo-controlled studies European research results presented to the medical community for the first time in 1998 in Vienna appear to be of lesser value. Recombinant polyvalent vaccine based on OspC lipoprotein isolated from Borrelia burgdorferi sensu lato was used but only eighty volunteers from Aland Islands participated in the study.

Bacterial Vaccines↗
PubMed1998

Retinoid X receptor and c-cerbA/thyroid hormone receptor regulate erythroid cell growth and differentiation.

Nuclear receptors are important regulators of erythroid cell development. Here we investigated the impact of retinoid X receptor (RXR), retinoic acid receptor (RAR), and of the c-erbA/thyroid hormone (T3) receptor (c-erbA/TR) on growth and differentiation of erythroid cells using an in vitro culture system of stem cell factor-dependent erythroid progenitors. RXR, RAR, and c-erbA/TR-specific ligands were found to induce erythroid-specific gene expression and to accelerate erythroid differentiation in culture, with T3 being most effective. Furthermore, while ligand-activated c-erbA/TR accelerated differentiation, unliganded c-erbA/TR effectively blocked differentiation and supported sustained progenitor growth in culture. Thus, c-erbA/TR appears to act as a binary switch affecting erythroid cell fate: unliganded c-erbA/TR supports growth while ligand-activated c-erbA/TR induces differentiation. Additionally, to determine the impact of RXR for erythroid cell development, dominant interfering mutant RXRs, lacking the transcriptional activator functions AF-1 and AF-2, or AF-2 only, or the entire DNA-binding domain, were introduced into erythroid progenitor cells via recombinant retrovirus vectors and analyzed for RXR-specific effects. It was found that expression of wild-type RXR and of the RXR mutants devoid of AF-1 and/or AF-2 supported a transient outgrowth of erythroid cells. In marked contrast, expression of the dominant interfering deltaDNA-binding domain RXR, containing a deletion of the entire DNA-binding domain, was incompatible with erythroid cell growth in vitro, suggesting a pivotal role of RXR for erythroid cell development.

Animals↗
PubMed1998

[Structure and dynamics of electrocardiographic changes in patients with Lyme carditis (pilot study)].

A maximum of 10% of the patients suffering from Lyme borreliosis suffer from cardiac damage. This affection is usually the source of diagnostic doubts, mainly because of the significant variability of clinical manifestations, the objectivization of which is difficult. Great variability is pathognomic also for electrocardiograms. For a three-month period 7 patients aged 43 years (29-53) were followed up under conditions of ambulatory ECG monitoring, i.e. using Holter s dynamic electrocardiography (HM) and ECG transmission by telephone (TTM). The focus of interest and objective of this pilot study was evaluation of the structure and dynamics of ECG changes, in particular from the aspect of types and frequencies of ectopic activity of the atria and ventricles and the ECG correlate of symptomatic events. Findings pertaining to the incidence of symptomatic (total 67) as well as asymptomatic events (total 25) are valuable. Systematic ECG checks of patients with Lyme carditis revealed a relatively large number of cases of impaired rhythm with a completely asymptomatic course.

Adult↗
PubMed1997

[Estimation of the mean right atrial pressure using echocardiography].

The authors measured in a group of 30 patients invasively the pressure in the right atrium and at the same time or within 60 minutes the diameter of the interior vena cava and its changes in conjunction with respiration. They revealed a statistically significant relationship between all parameters of the diameter of the interior vena cava assessed by echocardiography and the mean right atrial pressure. The closest correlation was found in the index of the inspiration diameter of the inferior vena cava (p = 0.01; r = 0.824). A critical value of the index of the inspiration diameter of the inferior vena cava greater than or equal to 10 mm revealed patients with a pathologically elevated pressure in the right atrium with a 100% sensitivity and 88.9% specificity. Measurement of the diameter of the inferior vena cava and its respiratory variations is a suitable method for estimation of the mean right atrial pressure.

Adult↗
PubMed1996

[Borrelia burgdorferi as a cause of sick sinus syndrome?].

The authors describe the case of a 42 years old man, who was implanted a permanent pacemaker on the basis of the sick sinus syndrome, suspected to have been induced by the infection with Borrelia burgdorferi. The review of world literature has indicated that it is an exceptional indication of permanent cardiac stimulation.

Adult↗
PubMed1996

[Transmission of the electrocardiogram via telephone. Analysis of 10 years' experience].

BACKGROUND: The problem of impaired cardiac rhythm is in recent years in the foreground of the interest of cardiologists. This was influenced not only by the conclusions of the CAST study which changed the therapeutic pattern used for some years but above all the diagnostic pitfalls of impaired rhythm as regards detection and identification. The objective of the present study was to provide evidence of the advantages and usefulness of the method of telephone transmission of the electrocardiogram within the complex of other diagnostic procedures. METHODS AND RESULTS: The group was formed by 251 patients, incl. 186 men and 65 women, average age 51.7 years (range 19-85 years). The transmission of the ECG by phone was implemented by the system TESLAR (VUIS-CVUT) which comprises recording units and a terminal with a graphic outlet. A total of 3,727 electrocardiographic tracings were assembled. During their analysis the arithmetic mean was used as the characteristic of the position of the group or groups on the scale, the error of the mean expressing the ratio of the standard deviation to the number of cases. In nominal variables most frequently percentage expression was used, frequently with a confidence interval obtained from tables. Evidence of the usefulness of the method is the high rate of detected arrhythmias within emergency calls (88.5%), as compared with normal calls (10.6%) where the yield is close to that of Holter monitoring, however, with the advantage of time ad libitum and thus also a higher yield. CONCLUSIONS: The presentation of long-term experience with electrocardiograms by telephone confirms unequivocally the assumption that the method extends existing diagnostic possibilities in short-term, symptomatic, but sporadic arrhythmias, that it makes possible dispensarization of risk patients as well as patients with permanent pacemakers and that it improves the tactics of antiarrhythmic treatment.

Adult↗
PubMed1996

Avian stem cell factor (SCF): production and characterization of the recombinant His-tagged SCF of chicken and its neutralizing antibody.

Recombinant chicken stem cell factor (SCF) was produced in bacteria as a histidine-tagged protein (His delta SCF) and purified by affinity chromatography on an Ni(2+)-NTA agarose column. His delta SCF is devoid of signal peptide and transmembrane domains and therefore mimics a soluble form of SCF. We demonstrate that the factor is biologically fully active in supporting sustained proliferation of SCF-dependent red blood progenitor cells of chicken in vitro. Polyclonal SCF-specific antibodies were raised in rabbits and shown to display potent SCF-neutralizing activity. Thus, recombinant chicken His delta SCF together with the SCF-specific antibody provide valuable tools for studying the role of SCF and c-kit receptor in development, growth and differentiation of avian haematopoietic cells.

Amino Acid Sequence↗