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Biomedical subjects

J Skvor

Publications and source records attributed to J Skvor.

At least 19 recordsLinked to original sources
PubMed2006

Some biological actions of PEG-conjugated RNase A oligomers.

Previously we have shown that monomeric RNase A has no significant biological activity, whereas its oligomers (dimer to tetramer) prepared by lyophilizing from 50% acetic acid solutions, show remarkable aspermatogenic and antitumor activities. Furthermore, conjugates prepared by chemical binding of native RNase A to polyethylene glycol (PEG) have shown a significant aspermatogenic and antitumor activities. In this work we show that the chemical conjugation of PEG to the RNase A C-dimer, and to the two RNase A trimers (NC-trimer and C- trimer) decreases the aspermatogenic activity of the oligomers while increasing their inhibitory activity on the growth of the human UB900518 amelanotic melanoma transplanted in athymic nude mice. Moreover, the PEG-conjugated RNaseA oligomers are devoid, like the free oligomers, of any embryotoxic activity.

Animals↗
PubMed2006

Hypertrophic cardiomyopathy--molecular genetic analysis of exons 9 and 11 of the TNNT2 gene in Czech patients.

OBJECTIVES: Our research is a pilot study that specializes in the molecular genetic investigation of the TNNT2 gene in Czech patients with HCM/FHC disease. This study was initiated with exons 9 and 11 of TNNT2 because of their crucial role in the binding ability of cardiac troponin T to alpha-tropomyosin, and continued with analyses in other regions of the gene. METHODS: Hundred and eighty-one Czech probands with HCM/FHC were enrolled in this study. The study group consisted of 24 families with FHC and probands without FHC history but with HCM diagnosis. The clinical diagnosis was based on echocardiography. DNA was isolated from peripheral blood lymphocytes and subsequently analyzed by the polymerase chain reaction (PCR), followed by DNA sequencing analyses, which were cross-sequenced. RESULTS: The DeltaGlu160 mutation was observed in a sequence of the TNNT2 gene in a patient with the severe form of hypertrophic cardiomyopathy. No sequence alteration was found in exons 9 and 11 of the TNNT2 gene found in the rest of the DNA samples. CONCLUSION: The DeltaGlu160 mutation was observed in patients with severe forms of hypertrophic cardiomyopathy. This region is responsible for binding troponin T to alpha-tropomyosin. This mutation may lead to functional and structural effects on the troponin T protein. Mutations in this region are reported relatively rarely and therefore it was unique to observe the DeltaGlu160 mutation in our study.

Base Sequence↗
PubMed2006

Mung bean sprout (Phaseolus aureus) nuclease and its biological and antitumor effects.

Bovine seminal ribonuclease (BS RNase), a dimeric homolog of bovine pancreatic ribonuclease (RNase A), is known to display special biological activities namely cytotoxicity for human tumor cells. Because some plant ribonucleases have a similar mass weight and structure as the animal ribonuclease, effects of a commercial product of Mung bean (Phaseolus aureus) nuclease (PhA) were studied on proliferation of ML-2 human tumor cells, as well as it's aspermatogenic, embryotoxic, immunogenic, and immunosuppressive activity, and therapeutic efficiency in athymic mice bearing human melanoma tumor. Concerning the antiproliferative activity, PhA nuclease was almost non-effective in vitro on ML-2 cells and also immunosuppressive activity on human lymphocyte in mixed culture was very low compared to that of BS RNase. However, significant antitumor activity was detected on human melanoma tumor after intratumoral or intraperitoneal administration into the mice. Furthermore conjugate of PhA nuclease with polyethylene glycol (PEG) injected seven times at the dose of 10 microg intraperitoneally showed identical antitumor activity as that of bovine seminal ribonuclease (BS RNase) injected by the same way at ten times higher dose. Both PhA and BS RNases exerted strong aspermatogenic effect on the width of spermatogenic layers while RNase A administration at ten times higher concentration was ineffective. PhA nuclease when compared by means of antibody cross reaction with RNase A, BS RNase and wheat leaf neutral RNase (WLN-RNase) was found to be immunologically similar to RNase A and WLN-RNase, meanwhile BS RNase showed much higher antigenicity in comparison with them.

Animals↗
PubMed2004

Development of an indirect competitive ELISA for detection of Campylobacter jejuni subsp.jejuni O:23 in foods.

An indirect enzyme immunoassay for rapid detection of Campylobacter jejuni subsp. jejuni 0:23 has been developed. Optimum concentrations of immobilized cells, polyclonal chicken IgY, and rabbit anti-IgY antibody-horseradish peroxidase conjugate were 3.1 CFU/nL, 10 microg/mL, and 8 microg/mL, respectively. Under such conditions, the detection limit reached 50 CFU/microL, limit of quantification being 480 CFU/microL. By testing 5 chromogens, viz. 1,2-benzenediamine, 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid), 3,3',5,5'-tetramethylbenzidine, bi(4,4'-anisidine) and 3-methyl-2-benzothiazolinone hydrazone, in horseradish peroxidase substrate, 1,2-benzenediamine or 3,3',5,5'-tetramethylbenzidine as H-donors in the enzyme substrate provided the highest ELISA sensitivity. The applied polyclonal antibody was specific for homogeneous antigen. The cross-reactions were observed only with one strain of C. sputorum subsp. sputorum (21.5 %) and with G+ bacterium Micrococcus luteus (6.1 %). Preliminary tests have been performed with a limited number of artificially contaminated food samples. No matrix effects on the ELISA sensitivity were observed. The results (by means of ELISA) were comparable with those given by both a standard cultivation method performed according to CSN ISO 10272 and commercially available Singlepath Campylobacter GLISA-Rapid Test.

Animals↗
PubMed1999

The detection of human beta 2-microglobulin by grating coupler immunosensor with three dimensional antibody networks.

Immunosensors for the detection of human beta 2-microglobulin (B2M) were prepared by immobilisation of covalently crosslinked assemblies containing various numbers of molecular layers of monoclonal antibody against B2M (anti-B2M) on the surface of a Ta2O5 grating coupler sensor. The immobilisation procedure consisted of repeated successive adsorption of anti-B2M and dextran sulfate (DS) followed by glutaraldehyde (GA) crosslinking of anti-B2M and washing out DS. The flexibility of the resulting anti-B2M networks was evaluated from the sensor response to the reversible expansion and contraction of the networks induced by changing pH of the ambient solution. A decreased GA concentration and the use of a higher-molecular-mass DS increased the network flexibility. The sensor sensitivity to B2M increased with increasing flexibility of the antibody networks and with increasing number of anti-B2M molecular layers, indicating that B2M can penetrate inside the antibody network.

Adsorption↗
PubMed1998

Effect of salt concentration gradient on separation of different types of specific immunoglobulins by ion-exchange chromatography on DEAE cellulose.

A three-stage process, consisting of an ammonium sulfate precipitation step, dialysis desalination with microporous anion-exchange Neosepta membranes and anion-exchange chromatography on DEAE-cellulose DE-52 was used for the isolation of mouse monoclonal antibodies specific against different antigens. The ascites fluids contained monoclonal antibodies against human IgG, against horseradish peroxidase and against the heavy chain of human IgM. The effect of the salt concentration gradient in the elution buffer was examined with the aim of optimizing chromatographic conditions. The quality of separation of protein zones was determined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis under non-reducing conditions. The immunoreactivity of purified monoclonal antibodies was determined by enzyme-linked immunosorbent assay using a solid-phase adsorbed antigens against which each monoclonal antibody type was directed.

Animals↗
PubMed1998

Immobilisation of multilayer bioreceptor assemblies on solid substrates.

Multilayer assemblies were prepared by alternating adsorption of monolayers of monoclonal antibody against horse radish peroxidase (anti-HRP) and dextran sulfate (DS) on solid supports at acid pH. After crosslinking with glutaraldehyde, DS was washed out of the film with buffered physiological saline, while the antibody remained immobilised on the support. Assembly was monitored in situ on germanium supports by infrared multi-internal reflection spectroscopy. The binding capacity of the immobilised antibodies for HRP was measured by ELISA and by optical waveguide light mode spectroscopy. The activity of an immobilised anti-HRP bilayer was approximately twice that of a monolayer prepared by simple physiosorption. An addition of further anti-HRP layers could increase the activity only up to 2.5 of the monolayer activity independently of a number of layers in the assembly. The non-specific adsorption of proteins from human blood plasma was three times lower on the immobilised anti-HRP multilayer film than on the surface covered only with a physiosorbed anti-HRP monolayer.

Antibodies, Monoclonal↗
PubMed1995

Separation of specific immunoglobulin. 1. Desalination using a membrane system.

Separation of the ammonium sulfate precipitated protein fraction of mouse ascitic fluid, containing the specific immunoglobulin (pI 6.7-6.8; molecular weight 180000), from ammonium sulfate was investigated by means of non-traditional dialysis, based on the difference in diffusion rates of small and large molecules through porous membranes. The experiments were carried out in spiral membrane modules equipped with a Neosepta (AM-2 or ACS-SB) anion exchange membrane and a microfiltration membrane (Synpore or Sartorius). To enhance the driving force for penetration of ammonium sulfate and low-molecular-weight components from solution of ascitic protein fraction into water, a counterpressure was imposed on the side of microfiltration membrane. The flow rate, counterpressure and the pore sizes of microfiltration membranes had a significant effect on the separation process, as expected. The type of the anion exchange membrane had only a small effect. This process makes it possible to desalt the immunoglobulin fraction with high purity and yield in a few hours instead of 5 days.

Ammonium Sulfate↗
PubMed1993

[Palpation and sonographic evaluation of the size of the thyroid gland].

The author compared in 88 13-year-old children evaluation of the size of the thyroid gland by palpation and sonography. Evaluation by the two methods was in agreement in 64 cases (73%) and controversial in 24 cases (27%). Palpation led in 24 instances to overestimation of the size and in 7 children (8%) to underestimation, as compared with sonography. Sonography is an essential method for evaluation of the thyroid gland in children.

Adolescent↗
PubMed1993

[Muscular exertion--"embarrassment" in the evaluation of aminotransferases and creatine kinase serum levels].

The authors draw attention to the problem of elevated values of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatine kinase (CK) serum activities in adolescents which they encountered recently in two patients hospitalized in their clinic. In common practice it is important when evaluating results of ALT, AST and CK in serum to take into account the effect of physical load, encountered frequently in this age group of adolescents.

Adolescent↗
PubMed1991

[Results of the diagnosis of nodular goiter in children].

The authors submit diagnostic conclusions in 28 children with nodular goitre aged 7-15 years. Twenty-four children had a mononodular goitre and 4 a multinodular one. Sixteen children were operated and histological examination revealed three times adenoma, twice carcinoma, three times a colloid node, four times a cyst and four times lymphatic thyroiditis. In 10 non-operated children in one a cyst was found and in nine lymphocytic thyroiditis. The authors submit diagnostic conclusions in 28 of different examination methods in the differential diagnosis of nodular goitre in children--red cell sedimentation rate, haemogram, X-ray of the lungs, palpation functional examination of the thyroid gland, sonography, scintigraphy, assessment of autoantibodies, hormonal suppression, aspiration cytology and histological examination.

Adolescent↗