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Biomedical subjects

P Kertai

Publications and source records attributed to P Kertai.

At least 37 records · Page 2Linked to original sources

A follow-up study of the progression or spontaneous regression of leukemia in mouse strains.

C3H/He-mg and AKR mice were injected intraperitoneally with lymphocytes prepared from the spleen of (C3H/He-mg x AKR)F1 hybrid mice bearing Gross-virus leukemia. Lymphocyte suspensions were prepared from the spleen, mesenteric lymph node and thymus of mice at different days after the injection and analyzed for the ratio of leukemic to normal lymphocytes with a flow cytometer. The size and the fluorescein content of the cells incubated with fluorescein diacetate served for the distinction between normal and leukemic lymphocytes. After injection with leukemic lymphocytes, lethal leukemia developed in the AKR strain, whereas the C3H/He-mg strain was characterized by a spontaneous regression after a transient development of leukemia. The percentage of leukemic lymphocytes was the highest in the spleen and it was the lowest in the thymus regardless of the stage of the disease. In the thymus of C3H/he-mg mice the leukemic lymphocytes could be detected only during the crisis period.

AKR murine leukemia virus↗

Transplacental effects of carcinogens and non-carcinogens on activities of pyruvate kinase and lactate dehydrogenase as well as isozymic pattern of LDH in mouse lung.

The carcinogens, urethane (URTH), 3-methylcholanthrene (MCA) and dimethylnitrosamine (DMN) given to pregnant mice enhanced permanently the activities of pyruvate kinase (PK) and lactate dehydrogenase (LDH) in the lungs of offspring even well before the appearance of lung tumours. The noncarcinogenic analogues phenylurethane (PHUR) and pyrene (PYR), had no effect on PK or LDH activity. The non-carcinogenic pulmonary toxicant Paraquat (PAR) elicited only a temporary elevation in the activities of the enzymes tested. The H:M ratio of LDH sub-units in the lung tissue was permanently decreased by URTH administered transplacentally. PAR caused only a temporary decrease in the H:M ratio, while PHUR had no effect on the isozymic pattern of LDH.

Animals↗

Regulation of glycolysis and oxygen consumption in lymph-node cells of normal and leukaemic mice.

Lymph-node cells of (AKR X C3H) F1 leukaemic mice showed a considerable increase of glycolytic activity and O2 consumption. The glycolytic enzymes phosphofructokinase, pyruvate kinase, aldolase and lactic acid dehydrogenase showed increased activities in leukaemic conditions. Studies on permeabilized leukaemic and normal lymph-node cells, and assays on partially purified phosphofructokinase and pyruvate kinase enzymes, revealed that the enhanced glycolysis of the tumour cells was due to the predominance of glycolytic isoenzymes relatively insensitive to the natural metabolic inhibitors. The glycolytic enzyme hexokinase showed decreased activity in leukaemic conditions, owing to a subcellular translocation of its bulk from the cytosol to the mitochondrial fraction. Association of hexokinase with the mitochondria accounted for an ATPase-like stimulatory action on cell respiration which can explain the increased O2 uptake of leukaemic cells.

Adenosine Triphosphate↗

Characterization of living normal and leukemic mouse lymphocytes by fluorescein diacetate.

The esterases activity of normal and acute leukemic mouse lymphocytes and that of their homogenates was investigated using fluorescein diacetate (FDA) as a fluorogenic substrate. The activity proved to be the same for the two cell populations as well as for the homogenates prepared from them. In cell suspensions, having different osmolalities, the rate of FDA hydrolysis decreased significantly with the increasing osmolality only in the case of intact leukemic lymphocytes. changes in the membrane and cytoplasmic viscosity caused by increased or decreased environmental osmolality of cell suspensions occurred in the same direction and to the same extent for both normal and leukemic cells. Fluorescein, the fluorescent product of the hydrolysis, accumulates in leukemic lymphocytes, whereas it easily effluxes form normal lymphocytes. A flow microfluorimetry analysis of the cell population revealed that the fluorescein content of large leukemic lymphocytes was three times higher than that of small, normal ones. The observed differences specific for leukemic lymphocytes might be useful in detecting leukemic transformation in an early stage of acute lymphoid leukemia.

Animals↗

Effect of carcinogenic and non-carcinogenic chemicals on the activities of four glycolytic enzymes in mouse lung.

The activities of four glycolytic enzymes were measured in the lung homogenate of CFLP mice treated with a variety of carcinogens and non-carcinogens for mouse lung. The carcinogenic urethane, dimethylnitrosamine (DMNA), 3-methylcholanthrene (MCA), benzo[a]pyrene (BP), 7,12-dimethylbenz[a]anthracene (DMBA) and aflatoxin B1 enhanced the activity of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK) and lactate dehydrogenase (LDH) 28 days after a single intraperitoneal administration. These carcinogens also altered the ratio of LDH H and M subunits. In contrast, under the same conditions the non-carcinogenic phenylurethane, ethylformate, chrysene, perylene and pyrene, as well as the pulmonarily toxic Paraquat, butylated hydroxytoluene (BHT) and cadmium chloride (CdCl2), did not influence either the activities of the enzymes tested or the isozyme pattern of LDH.

Animals↗

Teratogenic effect of 2'-thiourea in the rat.

The compound 2'-thiourea was studied for teratogenic effect in fetal rats. A 0.2% aqueous solution of 2'-thiourea (Merck) was administered ad libitum to pregnant rats from the first to the 14th day of pregnancy. The pregnancy was counted from the day when sperm was found in the vaginal smear. In the treated rat fetuses hypoplasia of the brain and spinal cord, internal hydrocephalus, hypoplasia of the spinal ganglia, kypholordosis, micromelia, micrognathia, cleft palate, retarded tooth development, exophthalmus, coloboma, and cataract were observed. In addition, generalized haemorrhages were found all over the body. The changes were similar to those produced by ethylene thiourea treatment in rat fetuses.

Animals↗

Fluorescence energy transfer studies on normal and leukemic mouse lymphocytes.

Control and acute leukemic cells of AKR:Lac C3H mg:Lac/F1 hybride mice were labeled either with ethidium bromide or ethidium bromide plus fluorescamine. Theoretical and experimental evidence shows that the ethidium bromide binding ability of cells and the average efficiency of Förster-type fluorescence energy transfer between fluorescamine and ethidium bromide inside the cells depend on both the cell and dye concentrations. It is shown further that fluorescamine treatment enhances the uptake of ethidium bromide by both normal and leukemic cells. A sevenfold difference was found in ethidium bromide binding ability between normal and leukemic cells at optimal dye concentration.

Animals↗

Activities of four glycolytic enzymes (HK, PFK, PK, and LDH) and isozymic pattern of LDH in mouse lung tumor induced by urethan.

In the lungs of CFLP mice the activities of glycolytic key enzymes (HK, PFK, PK) and LDH as well as LDH isozymic pattern change in the course of life. The activities of these glycolytic enzymes in the lung tumors induced by urethan in CFLP mice are significantly higher than those in the normal adult lung and they are similar to those in the normal fetal lung. The isozymic pattern of LDH of pulmonary adenomas resembles that of the normal fetal lung, too.

Age Factors↗

Effect of 2-thiourea administered to pregnant rats on the thyroid and the protein bound iodine content of the offspring.

A 0.2% solution of 2-thiourea administered during the third or the second and third weeks of pregnancy increased the weight of the thyroid of 20-day old fetuses and newborn rats, and decreased the protein bound iodine content in their thyroid and serum. Similar changes were observed in those weanling rats whose mother had been given a 0.2% solution of thiourea during the period of lactation. Both the intrauterine changes and those occurring during lactation proved reversible. The findings point to the possibility of congenital or infantile thyroid injury caused by thiourea derivatives taken up from the environment.

Animals↗