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J T Novák

Publications and source records attributed to J T Novák.

13 recordsLinked to original sources
PubMed1991

Monoclonal antibodies against human antithrombin III.

Three monoclonal antibodies identified as D8, B11 and C5 of different specificities have been produced against human antithrombin III (AT). The apparent dissociation constants (Kd app) of the AT-antibody interaction were determined by ELISA method: Kd app (D8) = 2.4 nmole, Kd app (B11) = 13 nmole, Kd app (C5) = 24 nmole. All three antibodies reacted with isolated AT on immunoblots obtained with "native" PAGE. The D8 antibody also reacted with plasma and serum AT while B11 antibody reacted with serum thrombin-antithrombin (TAT) complexes as well.

Animals↗
PubMed1989

Three-dimensional reconstructions of nucleolus-organizing regions in PHA-stimulated human lymphocytes.

Ultrastructure and three-dimensional distribution of nucleolus-organizing regions have been studied on ultrathin serial sections of PHA-stimulated human lymphocytes. During the 48 hr of activation the size of fibrillar centers (FCs) decreased from 0.6-0.9 microns to 0.2-0.3 microns and the number of FCs increased rapidly from one to 75-107 per cell. The number of fibrillar complexes (i.e. associations of a different number of FCs connected by the dense fibrillar component) also increased but did not reach the maximum number of nucleolar organizers presented here. Three-dimensional computer reconstructions of fibrillar complexes showed that lymphocyte activation was accompanied by early (2-4 hr) changes in the shape of the primary fibrillar center. Invagination of the dense fibrillar component on its surface occurred and division into two or more smaller FCs followed. Gradually, the typical structure of the nucleolus with several fibrillar complexes and many FCs was formed. These results confirm the hypothesis of fibrillar complex-nucleolar organizer correlation published recently.

Humans↗
PubMed1986

Effect of ribonucleases on cell-mediated lympholysis reaction and on GM-CFC colonies in bone marrow culture.

Natural dimer of bovine seminal ribonuclease (AS RNase) suppressed markedly DNA synthesis in allogeneic mixed lymphocyte culture (MLC) of normal human lymphocytes and simultaneously inhibited induction of cytotoxic effector cells within the sensitization phase of indirect cell-mediated lympholysis (CML) reaction. The last purification step of the AS RNase isolation procedure did not increase the suppressive activity of AS RNase compared to a less purified preparation (ZS RNase), thus, the later preparation was mostly used. ZS RNase (10 micrograms/ml) caused 50% inhibition of MLC reaction whereas pancreatic ribonuclease (A RNase) was 10 times less effective. The suppressive effect of RNases added in the beginning of the sensitization phase of the CML reaction correlated with that observed in the MLC reaction. The concentrations of ZS RNase (10 micrograms/ml), A RNase (100 micrograms/ml), and additionally tested cyclosporin A (0.5 microgram/ml) resulted in nearly total abrogation of cytolysis in CML. ZS RNase added after the sensitization of effector cells did not influence their cytolytic action on target cells within the destruction phase of CML. Natural killer and killer cell activities in normal peripheral lymphocytes were not inhibited by ZS RNase at the concentration of 330 micrograms/ml. ZS RNase (20 micrograms/ml), cocultivated 1 h with normal human bone marrow cells and then washed off, enhanced formation of GM-CFC colonies in semisolid agar culture up to 200%. Simultaneously tested antilymphocyte globulin increased the number of GM-CFC colonies at the average of 128%. This stimulating effect on colony formation appeared also in bone marrow culture of patients suffering with various hematological disorders. The possibility of utilizing the preparations gained from seminal plasma in clinical bone marrow transplantation is discussed.

Antilymphocyte Serum↗
PubMed1983

Study on immunosuppressive activity of alpha-globulin fraction of human blood plasma.

Immunosuppressive activity of alpha-globulin fraction of human blood plasma (Cohn fraction IV) was studied to determine the possible clinical utilization of this fraction as such, purified, or as the starting material for isolation of the active factor. The ethanol fractions IV, isolated and waste in the production of blood derivatives were found to be directly inapplicable because of relatively low activity and poor solubility. Therefore purification experiments were done to remove the denatured proteins and lipids and to increase the specific activity, they were performed on laboratory scale using DEAE ionex chromatography, and on semipilot scale utilizing the principles of ethanol fractionation of plasma. From the viewpoint of technology, the latter procedure seems more feasible; partial purification yielded good solubility and somewhat higher specific activity. Under study are further techniques capable of eliminating the contaminating proteins with do not carry the immunosuppressively active component, as well as the effectivity of pasteurization at 60 degrees C/10 hrs., which seems indispensable with respect to inactivation of infectious hepatitis viruses and the potential clinical application. Experimental isolations of the active component have led immunosuppressively active low-molecular part, which, however, is chemically nonhomogeneous. Its subsequent subfractionation will be necessary.

Animals↗
PubMed1982

Human lymphocyte culture in semi-solid medium.

We pointed out some sources of variations in the results obtained by the method of human peripheral lymphocyte culture in semi-solid medium. The influence of changes in five important parameters of the two-layer method was studied: agar concentration in the upper layer, cell concentration, mitogen dilution, type of culture medium and serum. We found that the optimal conditions for lymphocyte culture and for the evaluation of the results were 0.3% agar concentration in the upper layer, the concentration of 5 x 10(5) cells/ml, and a double dilution of phytohaemagglutinin. Of the culture media tested, MEM with 0.2% Bactotryptose supplemented with 20% inactivated mixed human serum proved most appropriate. Cells in lymphocyte colonies were characterized morphologically, cytochemically and by means of basic membrane features. The possibilities of using the method in clinical work are shown and the necessity of standardizing the culture technique is emphasized.

Agar↗
PubMed1975

Autoimmunity as possible evoking factor of some so-called idiopathic bone marrow hypoplasias.

Patients with bone marrow hypoplasia or aplasia were examined using the method of lymphocyte blast transformation and the MIF production test. The experimental results demonstrated the presence of an autoimmune process in these patients. A good congruence of the methods was demonstrated. Possible role of the autoimmune process in the pathogenesis of the disease as well as the reasons for the autoimmunity development and the therapeutical implications of these findings are discussed.

Autoantibodies↗