Biomedical subjects

L Svobodová

Publications and source records attributed to L Svobodová.

16 recordsLinked to original sources

PubMed2004

Properties of mixed alkanethiol-dendrimer layers and their applications in biosensing.

We studied the properties of mixed alkanethiol-dendrimer layers on a gold support and their application in biosensing. We showed that properties of glucose sensor can be modified using a different ratio of 1-hexadecanethiol (HDT) and poly(amidoamine) dendrimer of first generation (G1). The cyclic voltammetry in the presence of the redox couple, Fe(CN)(6)(3-)/Fe(CN)(6)(4-), was used for estimating how effectively the layer blocks the redox probe's access to the electrode surface. A scanning electrochemical microscope (SECM) was used to image the resulting distribution of the organic compounds. We found that with increasing content of dendrimers, the integrity of the layers was improved.

Biosensing Techniques↗

PubMed2004

Activation and modulation of ligand-gated ion channels.

Ligand-gated ionic channels are integral membrane proteins that enable rapid and selective ion fluxes across biological membranes. In excitable cells, their role is crucial for generation and propagation of electrical signals. This survey describes recent results from studies performed in the Department of Cellular Neurophysiology, Institute of Physiology ASCR, aimed at exploring the conformational dynamics of the acetylcholine, glutamate and vanilloid receptors during their activation, inactivation and desensitization. Distinct families of ion channels were selected to illustrate a rich complexity of the functional states and conformational transitions these proteins undergo. Particular attention is focused on structure-function studies and allosteric modulation of their activity. Comprehension of the fundamental principles of mechanisms involved in the operation of ligand-gated ion channels at the cellular and molecular level is an essential prerequisite for gaining an insight into the pathogenesis of many psychiatric and neurological disorders and for efficient development of novel specifically targeted drugs.

Allosteric Regulation↗

PubMed2003

[Lymphangioleiomyomatosis in a menopausal woman].

Lymphagioleiomyomatosis is a rare pulmonary disease which affects mainly women of childbearing age. An observation of lymphangiomyomatosis in a menopausal woman or in men is considered very unusual. We report a case of lymphagioleiomyomatosis in a 60-year-old woman.

Female↗

PubMed2003

Effects of oxidation on changes of compressibility of bovine serum albumin.

The methods of ultrasound velocity and density measurements were used to study the adiabatic compressibility of bovine serum albumin (BSA) during its oxidation by the prooxidants Cu2+ and 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH). We did not find changes of compressibility of BSA in the presence of copper ions at rather high molar ratio Cu2+/BSA = 0.66 mol/mol. This can be explained by binding of the Cu2+ to the binding site of BSA and thus protecting the prooxidant action of the copper. However, AAPH-mediated oxidation of BSA resulted in an increase of its apparent specific compressibility (psik/beta0). These changes could be caused by the fragmentation of the protein.

Amidines↗

PubMed2002

Properties of glucose biosensors based on dendrimer layers. Effect of enzyme immobilization.

The properties of glucose biosensors based on dendrimer layers on a gold support, which depend on the method of immobilization of glucose oxidase (GOX), were studied by amperometry. The kinetic parameters of enzymatic reactions, response time, sensitivity, detection limit, linear range, and enzyme turnover were determined. We showed that a more stable and sensitive sensor was obtained when GOX was immobilized on the dendrimer by crosslinking with glutaraldehyde in vacuum. This biosensor was stable for at least eight weeks. The response time was approximately 1.3 min, the detection limit of glucose was 25 micro M, and the apparent Michaelis-Menten constant was relative low ( K(m)=1.1+/-0.1 mM) in comparison with that for GOX in solution. The reason for these differences is discussed. The example of the application of the developed biosensors for the detection of mercury is also presented. The inhibitory effect of mercury on GOX activity was observed at mercury concentration of 100 nM.

Biosensing Techniques↗

PubMed2002

[Interstitial pulmonary processes].

New classification of the idiopathic interstitial pneumonias on the basis of the structural characteristics is presented. The contemporary classification includes four types of disease, differing in the clinical symptomatology, reaction to therapy and prognosis.

Humans↗

PubMed2001

Liposome aggregation in presence of the sweeteners cyclamate and saccharine.

The interaction of the sweeteners saccharine and cyclamate with large unilamellar liposomes and planar bilayer lipid membranes (BLM) was studied. Application of the methods of light scattering and sound velocimetry showed that saccharine induces aggregation of liposomes, while cyclamate probably caused increase of the hydration of liposome surface. The sweeteners induced changes of BLM compressibility in a direction perpendicular to the membrane plane. The cyclamate induced considerably larger decreases in the elasticity module than saccharine. The obtained results show that both saccharine and cyclamate interacts with the surface of lipid bilayer and could modify the physical properties of lipid membranes.

Cyclamates↗

PubMed1996

[High-resolution computer tomography in the diagnosis of cryptogenic fibrosing alveolitis. Correlation with pulmonary function and bronchoalveolar lavage].

BACKGROUND: High resolution computed tomography (HRCT) revealed new findings as regards changes associated with cryptogenic fibrotizing alveolitis. So far views on changes suggesting activity of the disease are not uniform and they were not yet confronted with examinations of fluid obtained by bronchoalveolar lavage (BALT). The objective of the present work is to evaluate the contribution of HRCT to the assessment of the activity of the disease and compare the findings with the examination of BALT. METHODS AND RESULTS: The authors evaluated the HRCT examination made in 52 patients with histologically confirmed cryptogenic fibrotizing alveolitis and in 39 of them the finding was confronted with the BALT examination. Signs of active inflammatory disease according to HRCT comprised a ground-glass increase of the density in 80.8%, centrilobular micronodules in 17.3% and a prominence of centrilobular structures in 32.7%. The suggested extent of affection of the pulmonary parenchyma assessed according to HRCT correlated well with the degree of dyspnoea, restrictive and obstructive ventilation disorder, pulmonary diffusion and with hypoxaemia. The authors confirmed also an inverse correlation between the grade assessed by HRCT and the percentage of lymphocytes in BALT. CONCLUSIONS: The investigation confirmed the contribution of HRCT in the diagnosis of patients with cryptogenic fibrotizing alveolitis, it confirmed the complementary importance of HRCT and BALT examination when assessing the activity of the disease and its asset when monitoring patients during treatment.

Adolescent↗

PubMed1989

[The clinical picture of pulmonary tuberculosis over the past 40 years].

Most patients with pulmonary tuberculosis present to their physician because of the symptoms of this disease. This study was aimed at finding out how the clinical picture of pulmonary tuberculosis diagnosed for the first time changes in the patients hospitalized at our department in the years 1948-1986. Furthermore, the percentage of asymptomatic patients, the frequency of detectable cavern and mycobacteria tuberculosis were established. During the time period studied a change in clinical picture of the disease occurred as seen on the 13 symptoms followed. The previously common haemoptysis is a rarer symptom of tuberculosis at present (17.5% in the 1948-1950 population compared to 5.0% in the 1983-1986 population). There is an increasing number of patients in which tuberculosis manifests itself by breathlessness (2.3% of the 1948-1950 population compared to 10.9% in the years 1979-1981). In the whole period studied patients with symptoms prevail, the difference between the 1948-1950 period (71.1%) and that of 1979-1986 (67.0%) is not statistically significant. The number of patients with cavernous tuberculosis is decreasing (75% of patients in the years 1948-1950, 37% of patients in the years 1983-1986), there is an increase in bacteriologically proven diseases (33.9% of the 1948-1950 population, 73.0% of that of 1983-1986). The change in the clinical picture of tuberculosis is connected with the improvement of social conditions of the whole population, introduction of compulsory BCG vaccination and effective therapy, as well as bovine tuberculosis elimination. The change in the clinical picture of the disease is also influenced by the ever increasing mean age of the patients.

Adult↗

PubMed1989

[The clinical picture of pulmonary tuberculosis during the course of 39 years].

The change of signs and symptoms of pulmonary tuberculosis detected for the first time during the years 1948 through 1986 is analysed. During the entire period, the majority of patients attended the physician because of symptoms. Between 13 different evaluated symptoms cough was permanently most frequent. The other symptoms changed in their prevalence. The mean age of the patients increased from 29.7 to 59.0 years. The proportion of patients with cavities decreased from 75% to 37%. The increase of the proportion of patients in whom M. tuberculosis was detected, from 33.9 to 73.0%, is explained by the growing intensity of bacteriological examinations. To provide early case finding, health education of the population and appropriate qualification of physicians and other health providers are required at present as well as in the past.

Adult↗

PubMed1979