Search PubMed⌕ Search

Biomedical subjects

J Novotný

Publications and source records attributed to J Novotný.

At least 73 records · Page 4Linked to original sources
PubMed1994

Application of epirubicin containing albumin microspheres in the experimental therapy of breast cancer.

In the experiment we attempted to use albumin microspheres as carriers of cytostatics to acquire a higher drug concentration in the tumor for a longer time. It was expected that the efficiency of a treatment with a microsphere-entrapped epirubicin would be better than a treatment with microsphere-free drug. Albumin microspheres containing epirubicin were prepared by ultrasonic homogenization in oil and heat denaturation. In vitro experiments and the test for biological activity on human breast carcinoma cells implanted into Nu/Nu mice were carried out. Growth of tumors in the group of mice treated with microsphere-entrapped epirubicin was inhibited more effectively in comparison with growth of tumors in the group treated with microsphere-free drug. These results suggest that the change of the drug form can enhance antitumor effect of epirubicin and that albumin microspheres are suitable drug carriers.

Animals↗
PubMed1994

Comparison of two protocols used in exercise testing in chronic heart failure patients.

UNLABELLED: Spiroergometrical testing with the load graded upto symptom-limited maximum with the determination of anaerobic threshold begins to be a routine method in exercise testing of cardiac patients. Functional parameters according to available data depend on the source of load and may be influenced by the protocol of testing, too. That is why we decided to compare two protocols used in chronic heart failure patients exercise testing. 11 male and 3 female patients (NYHA II, III) suffering from chronic heart failure were subjected to the symptom-limited tests (protocol A-0.25 W.kg (-1/3 minutes with one minute breaks; protocol B-25 W + 10 W/2 minutes). There was no statistically significant differences in the symptom-limited values of main functional parameters. The AT level parameters did not differ significantly, as well. Anaerobic threshold could be determined in all patients using the protocol A and in 11 cases using the protocol B. The difference in rates was not statistically significant. The workload duration using the protocol B was significantly shorter (9.7 +/- 3.8 minutes vs. 16.4 +/- 3.6 minutes). CONCLUSIONS: Protocol B is less time demanding and therefore it is more suitable for determination of the symptom-limited parameters in the clinical routine. Anaerobic threshold can be determined by protocol A more often than by protocol B. Therefore, protocol A appears to be more suitable for the individual prescription of the appropriate physical activity and for scientific purposes, too.

Anaerobic Threshold↗
PubMed1993

[The cardiorespiratory and metabolic response in diabetics to physical loading in the laboratory and under field conditions].

The authors investigated and compared the response of 26 men with insulin dependent diabetes mellitus to a physical load in the laboratory (bicycle spiroergometry with a work load graded up to a maximum) and recommended 20 min. walking or running under field conditions (constant speed beneath the "anaerobic threshold"). The mean maximal oxygen uptake per minute in the laboratory (2.81 +/- 0.47 l) was insignificantly lower than reference values and combined with the maximal minute heart rate (mean 175 +/- 17) very variable. During the load under field conditions the oxygen uptake practically did not change (1.64 +/- 0.59 l/min.) but the heart rate increased due to the declining stroke volume. The blood sugar level in the laboratory and during field exercise declined significantly. In the laboratory the base deficit and lactacidaemia increased markedly; under field conditions their concentration increased slightly and did not pass the anaerobic threshold level. The pyruvate, acetoacetate and beta-OH-butyrate concentrations did not change much and were consistent with the response of well controlled diabetic patients.

Adult↗
PubMed1993

[Are central hemodynamics the decisive factor in the manifestation of chronic heart failure?].

In the past some authors revealed that data assembled during examinations of the central haemodynamics, echocardiography, subjective complaints, physical findings and load tolerance in patients with chronic heart failure are not mutually consistent. The authors examined therefore comprehensively 40 patients with different grades of cardiac failure. They revealed very loose relations between the grade of functional classification, echocardiographic and invasive haemodynamic parameters at rest on the one hand and spiroergometric indicators on the other hand. Closer relations with spiroergometric findings were obtained with values of invasive haemodynamic parameters after a load, in particular values of the cardiac index, and systemic vascular resistance. The authors conclude that for clinical manifestations of chronic cardiac failure the peripheral circulation and tissue metabolism is at least equally important as changes of central haemodynamics. Moreover, the importance of the right ventricular function and diastolic cardiac function is not sufficiently appreciated.

Adult↗
PubMed1992

Serological diagnosis of parainfluenza virus infections: verification of the sensitivity and specificity of the haemagglutination-inhibition (HI), complement-fixation (CF), immunofluorescence (IFA) tests and enzyme immunoassay (ELISA).

Using four serological tests paired sera were examined of 117 patients with acute respiratory diseases, in whom parainfluenza viruses (PIV) infection was demonstrated by virus isolation, and of 41 patients with typical clinical mumps symptoms. Comparative analysis showed the high sensitivity of IFA and ELISA. A significant rise of antibodies in convalescent sera with homologous antigen of PIV was found in nearly 100 percent of cases. Only the sera of youngest children with high titres of persisting maternal antibodies remained without seroconversion. Cross heterologous antibody responses could be found by means of ELISA in 45% and by IFA in 10%, of patients who in the past experienced infection with one or more PIV or mumps virus--apart from homologous antibody reaction. HI and CF test proved to be less sensitive for detection of postinfections antibodies, especially in primoinfections with PIV types 1 and 2.

Antibodies, Viral↗
PubMed1992

A method for the preparation of purified antigens of coxsackievirus B3 from a large volume of cell culture supernatant.

A simple procedure was used for the concentration and partial purification of coxsackievirus B3 (Nancy strain). For a large-scale production of virus. Vero cells grown in roller bottles were used. Virus concentrate from a large volume of cell culture supernatant was prepared by precipitation with 6% (w/w) polyethylene glycol. This crude antigen was further purified by banding in cesium chloride gradient using ultracentrifugation. The infectivity and haemagglutination activity of virus were checked up during the whole procedure and the final recovery of infections virus was about 60%.

Animals↗
PubMed1991

Cultivation of psoriatic keratinocytes and an attempt to isolate and detect a specific psoriatic antigen.

Keratinocytes from psoriatic lesion and healthy skin region obtained from the skin of a psoriatic patient were cultivated on lethally irradiated 3T3 cells. They multiplied twice as quickly as normal keratinocytes from healthy skin. Ten antigen fractions were prepared from cell suspensions of psoriatic keratinocytes and from the medium left after their cultivation. Later, they were evaluated in ELISA tests performed with the sera of psoriatic patients and healthy persons. The presence of specific antigens was not demonstrated.

Antigens↗
PubMed1990

Properties and use of mumps viral antigen for detection of specific IgG and IgM antibodies in enzyme-linked immunosorbent assay.

Specific mumps virus antigens of three purification degrees have been prepared and their quality was evaluated in the enzyme-linked immunosorbent assay (ELISA) with specific human sera. Two enzyme immunoassays were elaborated, namely a simple sandwich method for IgG and the IgM-capture technique for IgM detection. Four different lots of mumps antigen were tested in these two ELISA systems. All antigens of corresponding purification degrees showed practically the same properties.

Antibodies, Viral↗
PubMed1990

[Cardiorespiratory fitness in children with type I diabetes mellitus].

The authors compared indicators of cardiorespiratory functions of 13 boys and 14 girls with insulin-dependent diabetes with the same parameters in a group of their healthy siblings and with mean values of the Czechoslovak population. No significant differences were found. Practically identical values of the decline of bases in the blood stream of healthy and sick children after a load suggest the ability of diabetics to compensate acidosis after a load. From the investigation it is apparent that in child diabetics in the prepubertal period the possibility of developing physical fitness is preserved. The general higher blood level in diabetics after a short intensive load declined, while it rose in siblings. Parameters of the internal environment differed greatly between individual subjects.

Blood Glucose↗
PubMed1990

[Detection of atrial septal defects using esophageal echocardiography].

By means of transoesophageal (oesophageal) echocardiography (TEE) the authors examined a group of 20 subjects. In 10 there was clinical suspicion (physical finding, ECG, X-ray) of an atrial septal defect. Common precordial echocardiographic examination (TTE) and dilution of indocyan green by means of an acustic sensing unit were negative or only marginally positive and did not provide a final decision. By means of TEE the defect was confirmed in 8 subjects by the finding of anatomical discontinuity of the septum and the presence of coloured Doppler shunt flow. In two subjects the finding was negative, in 10 controls no pathological findings were detected. The authors confirmed that TEE is a reliable method which proves even slight shunts in the area of the atrial septum. It is probably the most sensitive existing method.

Adult↗
PubMed1990

[Plasmocellular leukemia with IgD paraproteinemia].

The authors describe the case of an 80-year-old woman with a plasmocytoma IgD-lambda, which developed into plasmocellular leukaemia. The laboratory finding reminded at first of chronic lymphatic leukaemia. The correct diagnosis was assisted by marked leucocytosis with the release of a major number of plasmatic cells into the peripheral blood stream. The finding was confirmed on the basis of sternal puncture, cytochemical examination, immunochemical examination of the blood and urine and X-ray of the skull. Treatment led to marked clinical and laboratory improvement. The patient died, however, from pneumonia three months after establishment of the diagnosis. Post-mortem examination revealed an extensive infiltration of many organs and a myelomatous kidney. The authors present some differential diagnostic reflections on plasmocellular leukaemia.

Aged↗
PubMed1990

[Initial experience with transesophageal echocardiography].

The authors present their initial experience with a new echocardiographic method, transoesophageal echocardiography (TEE). From an oesophageal approach it gives a remarkable view of the anatomy and functional parameters of the heart in practically all examined patients. It opens also new diagnostic possibilities. The main advantages of the method include the possibility to use high frequency probes (5 MHz, or more), which visualize more subtile structures than transthoracic echocardiography (TEE). A valuable aspect is also the absence of interfering structures such as lungs and ribs.

Aortic Diseases↗
PubMed1989

[Comparison of absorbed doses from cobalt irradiation sources].

A comparison of absorbed doses from medical cobalt beams was performed by means of thermoluminescent dosimeters at all radiotherapeutic workplaces in Czechoslovakia. At most workplaces (58%) the deviation from the reference primary etalon placed at the Institute of Radiation Dosimetry of the Czechoslovak Academy of Sciences was below 3%. Neither of the workplaces exhibited deviation higher than 5%, indicating a good level of clinical dosimetry.

Cobalt Radioisotopes↗
PubMed1988

Structure of antibody hypervariable loops reproduced by a conformational search algorithm.

The antigen-combining site of antibody molecules consists of six separate loops supported by a conserved beta-sheet framework; antibody specificity arises from length and sequence variation of these 'hypervariable' loops and can be manipulated by transferring sets of loops between different frameworks. Irregular loops are the most difficult parts of protein structure to understand and to model correctly. Here, we describe two computer experiments where all the hypervariable loops were deleted from X-ray structures of mouse immunoglobulins and reconstructed using the conformational search program CONGEN. A protocol was developed for reconstruction of the hypervariable loops in McPC 603 antibody. Calculated loop conformations were generated and a model of the combining site was built from selected low-energy conformations. We then modelled hypervariable loops in another antibody molecule, HyHEL-5. Both models agreed well with the known crystal structures. Our results hold out promise for the success of future modelling studies of complete antigen-combining sites from amino acid sequences.

Algorithms↗
PubMed1988

Characterization of five epitopes of human renin from a computer model.

Antigenic determinants in proteins have been found to coincide with surface regions accessible to a large probe of 1-nm radius, which approximates the size of an antibody binding domain. To predict epitopes of human renin, a computer algorithm was used to calculate the accessibility of a model of the three-dimensional structure of human renin to a 1-nm probe. Of the 17 segments predicted to be epitopes or parts of epitopes, 6 were synthesized and tested for their recognition by 11 polyclonal antibodies prepared against pure human renin. Four peptides, Y-133-144, C-180-188, Y-211-224, and Y-300-310, were bound by some polyclonal anti-renin antibodies when tested in both a solution assay and an enzyme-linked immunosorbent assay (ELISA), and one peptide, C-290-296-G, was bound only in an ELISA. Of the five epitopes identified, peptide Y-211-224 seems dominant, since it was bound by all antisera in the solution assay and by 8 of the 11 in the ELISA. This peptide contains a disulfide loop, and the corresponding linear peptide obtained after reduction of the disulfide was not recognized by any anti-renin antisera in the solution assay. This suggests that the epitope is conformationally dependent and that a disulfide bridge linking cysteines-217 and -221 is present in the native structure of human renin. Purified immunoglobulins raised to peptides Y-133-144 and Y-211-224 (located near, but not at, the catalytic site) were found to inhibit the cleavage of human angiotensinogen by purified human renin but not the cleavage of a tetradecapeptide substrate representing the N-terminal region of angiotensinogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1988

Criteria that discriminate between native proteins and incorrectly folded models.

Various theoretical concepts, such as free energy potentials, electrostatic interaction potentials, atomic packing, solvent-exposed surface, and surface charge distribution, were tested for their ability to discriminate between native proteins and misfolded protein models. Misfolded models were constructed by introducing incorrect side chains onto polypeptide backbones: side chains of the alpha-helical hemerythrin were modeled on the beta-sheeted backbone of immunoglobulin VL domain, whereas those of the VL domain were similarly modeled on the hemerythrin backbone. CONGEN, a conformational space sampling program, was used to construct the side chains, in contrast to the previous work, where incorrect side chains were modeled in all trans conformations. Capability of the conformational search procedure to reproduce native conformations was gauged first by rebuilding (the correct) side chains in hemerythrin and the VL domain: constructs with r.m.s. differences from the x-ray side chains 2.2-2.4 A were produced, and many calculated conformations matched the native ones quite well. Incorrectly folded models were then constructed by the same conformational protocol applied to incorrect amino acid sequences. All CONGEN constructs, both correctly and incorrectly folded, were characterized by exceptionally small molecular surfaces and low potential energies. Surface charge density, atomic packing, and Coulomb formula-based electrostatic interactions of the misfolded structures and the correctly folded proteins were similar, and therefore of little interest for diagnosing incorrect folds. The following criteria clearly favored the native structures over the misfolded ones: 1) solvent-exposed side-chain nonpolar surface, 2) number of buried ionizable groups, and 3) empirical free energy functions that incorporate solvent effects.

Computer Simulation↗
PubMed1988

Protein engineering of antibody binding sites: recovery of specific activity in an anti-digoxin single-chain Fv analogue produced in Escherichia coli.

A biosynthetic antibody binding site, which incorporated the variable domains of anti-digoxin monoclonal antibody 26-10 in a single polypeptide chain (Mr = 26,354), was produced in Escherichia coli by protein engineering. This variable region fragment (Fv) analogue comprised the 26-10 heavy- and light-chain variable regions (VH and VL) connected by a 15-amino acid linker to form a single-chain Fv (sFv). The sFv was designed as a prolyl-VH-(linker)-VL sequence of 248 amino acids. A 744-base-pair DNA sequence corresponding to this sFv protein was derived by using an E. coli codon preference, and the sFv gene was assembled starting from synthetic oligonucleotides. The sFv polypeptide was expressed as a fusion protein in E. coli, using a leader derived from the trp LE sequence. The sFv protein was obtained by acid cleavage of the unique Asp-Pro peptide bond engineered at the junction of leader and sFv in the fusion protein [(leader)-Asp-Pro-VH-(linker)-VL]. After isolation and renaturation, folded sFv displayed specificity for digoxin and related cardiac glycosides similar to that of natural 26-10 Fab fragments. Binding between affinity-purified sFv and digoxin exhibited an association constant [Ka = (3.2 +/- 0.9) x 10(7) M-1] that was about a factor of 6 smaller than that found for 26-10 Fab fragments [Ka = (1.9 +/- 0.2) x 10(8) M-1] under the same buffer conditions, consisting of 0.01 M sodium acetate, pH 5.5/0.25 M urea.

Base Sequence↗