PubMed Health⌕ Search

Biomedical subjects

A Sedláková

Publications and source records attributed to A Sedláková.

At least 19 recordsLinked to original sources
PubMed1999

[Biochemical changes in apoptosis and methods for their determination (review)].

Apoptosis or programmed cell death is a physiological process which occurs at different biological states as well as at disease process. Morphologically it is characterized by the chromatine condensation and other changes with preserved integrity of plasmatic membrane. The major and most frequently studied biochemical characteristic of apoptosis is a DNA fragmentation. In our paper attention is directed to the early biochemical changes in cell membranes, i.g., the externalization of phosphatidylserine, hydrolysis of sphingomyeline on the ceramide and activation of phospholipases especially phospholipase A2. In one part we described the changes of cysteine proteases (caspases), which play a key role in the execution of apoptosis. These biochemical changes are associated with ceramide signalization of apoptosis. Briefly are presented also some dates about apoptosis induction with reactive oxygen radicals and the role of the arachidonic acid metabolites in this process. We consider the investigation and determination of these changes as important parameters of apoptosis at some diseases, e.g., cancer or degenerative diseases, and of their treatment.

Animals↗
PubMed1998

[Phospholipase A2: characteristics and function].

Phospholipase A2 (PLA2) hydrolyses membrane phospholipids (PL) and it may release arachidonic acid (AA)--the precursor of eicosanoids--from the sn-2 position. PLA2 and metabolites of its catalytic activity participate in many processes in the organism: metabolism of lipids, inflammation and immune reactions, membrane and tissue reparation, proliferation, and others. PLA2 as also an important element in the signal transduction. In the present article, PLA2 is characterised, classified into several types, and its mechanism of action together with its possible role in the disease processes are described. The attention is aimed at two forms of PLA2: The secretory (PLA2) of the type II which is associated with the inflammation injury, and the cytosolic PLA2 which is the main catalyst in the liberation of AA and which participates in the signal transduction. Other forms of PLA2 has been also described.

Arachidonic Acid↗
PubMed1988

Glycogenesis and lipogenesis from 14C-glucose in vivo in rats irradiated with fractionated doses of gamma rays.

Irradiation with fractionated doses is a specific form of stress and the data concerning these problems are topical for recent radiobiology, radiology and oncology. Interest in this present paper is focused on tissue glycogenesis and lipogenesis from U-14C-glucose in vivo in rats irradiated with fractionated doses of 2.39 Gy once a week. Analyses were done after 1-6 fractions, up to total accumulated doses of 2.39, 4.78, 7.17, 9.76, 11.95 and 14.34 Gy, which means LD50/30 for this experimental model. Fractionated irradiation of rats led to glycogen deposition and increased incorporation of 14C-glucose into the liver, heart and skeletal muscles, but not into brain glycogen. The ascertained changes were not dose-dependent. 14C-glucose was incorporated into the liver and adipose tissue lipids to a small extent, and synthesis of liver cholesterol increased only after the 5th and 6th fractions. A decreased concentration of hepatic lipids, especially of cholesterol, was observed from the 3rd to the 6th fractions.

Adipose Tissue↗
PubMed1988

In vivo studies of the relationship between the activation of lipid metabolism, postirradiation bone marrow cell proliferation and radioresistance of mice.

The effect of adaptation to intermittent feeding on the in vivo biosynthesis of fatty acids and total lipids in the epididymal adipose tissue, the liver and the bone marrow was studied in adult male mice (CBA/JPh x C57BL@10 ScSnPh)F1. At the same time the effects of the same experimental stimulus on the rate of regeneration (proliferation) of bone marrow cells after sublethal irradiation of animals and on the overall radioresistance of mice expressed as 30 days survival after whole-body gamma irradiation were determined. Intermittent feeding in mice has been shown to have a significant effect on the biosynthesis of fatty acids and total lipids in all the tissues studied, including bone marrow cells, the intensity of the effect being closely dependent on the duration of the experimental stimulus. Maximum stimulation of lipogenesis during realimentation was observed approximately within 1 week of adaptation, with a reduction of the metabolic responses thereafter. The intensity of bone marrow cell proliferation in mice irradiated in the realimentation phase was inversely proportional to the preirradiation degree of biosynthesis of fatty acids and total lipids: in a period of lower lipogenetic capacity of cells in the tissue studied (around the weeks 2-5 of adaptation) an increase in the regeneration potential of bone marrow cells was observed together with increased radioresistance of the mice. During the 1-week of adaptation the opposite proved to be the case. Attention is drawn to the possible participation of prostaglandins and lipid peroxides in the responses observed.

Adaptation, Biological↗
PubMed1986

Changes in lipoprotein lipase activity in the adipose tissue and heart of non-lethally X-irradiated rats.

After 16 h nocturnal deprivation of food, male Wistar rats were irradiated by a single whole body dose of 2.40 Gy X-rays. Both the irradiated and sham-irradiated (control) rats were pair-fed for the first six days after irradiation, but for the rest of the time they were fed ad libitum. Lipoprotein lipase activity (LPLA) in the adipose tissue fell between 24 and 48 h; LPLA in the heart fell at 24 h and 21 days and rose on the 14th days. The serum triacylglycerol concentration rose between 24 and 72 h. Comparison with the fed control group showed LPLA in adipose tissue to be reduced at 6 and 72 h and on the 28th day and raised between the 7th and the 14th day. In the heart it was raised at 1 h and between 72 h and the 14th day, it was reduced on the 21st day and rose on the 35th day. The triacylglycerol concentration was raised between 48 and 72 h and on the 28th day. Pair-feeding after non-lethal X-irradiation allowed more exact differentiation of the specific effect of ionizing radiation on LPLA in the adipose tissue and heart at the early post-irradiation intervals.

Adipose Tissue↗
PubMed1985

The role of adipose tissue in glucose utilization in irradiated rats.

The authors studied the conversion of U-14C-glucose to total lipids, fatty acids and glyceride glycerol in the epididymal adipose tissue of rats X-irradiated with a single whole body dose of 14.4 Gy X-rays. Analyses were carried out 1, 24, 48 and 72 h after irradiation. In the adipose tissue of irradiated rats, the incorporation of 14C-glucose into all the lipid fractions was raised throughout the whole time of observation (300-600% of the control value). Most of the 14C-glucose was incorporated into the glyceride glycerol fraction.

Adipose Tissue↗
PubMed1982

Some semantic patterns of cardiac patients.

The authors investigate the semantic patterns of patients who after a myocardial infarction are taking part in a long-term rehabilitation program. By means of a specially constructed semantic differential they measure and factor-analyze the attitudes of 50 male patients towards 15 clinico-medical concepts. Data from 60 healthy female controls yielded almost identical factor loadings for the stimulus terms, describing obviously the same perceptual structure having a strong temporal component. The spatial clustering of the concept reveals minor particularities which are specific for the view of the postinfarctional patients.

Attitude to Health↗
PubMed1981

Changes in rat liver and adipose tissue lipogenesis in the course of continuous gamma radiation.

Lipogenesis in liver of continuously irradiated rats (dose rate of 0.57 Gy per day for up to 25 or 30 days) was increased, in comparison with control animals, between 7 and 30 days. In the liver of fed rats it was approximately five times higher than animals fasted for 16 hours before sacrifice. Lipogenesis in adipose tissue was decreased on the third day of irradiation and its value was higher than in controls between 7 and 25 days. Glyceride glycerol synthesis in irradiated rats was increased compared with controls on the first, seventh and between 21 and 25 days of continuous irradiation. We suggest that the increase in lipogenesis in the liver of continuously irradiated rats is an important factor in lipid metabolism disorders caused by the continuous irradiation.

Adipose Tissue↗
PubMed1981

Metabolic changes after non-lethal x-irradiation of rats. II. Serum and tissue lipids.

Male rats of the Wistar strain were subjected to whole-body X-irradiation with 2.39 Gy (250 R) and after irradiation they were pair-fed with the sham-irradiated control group. One, 6 and 24 h, 2, 3, 7, 14, 21, 28, and 38 days after exposure the animals were sacrificed and examined for serum and some tissue lipids. In the first hours an increase in lipolysis in the white adipose tissue and accumulation of NEFA and TG in the liver predominated; PL level increased in serum and liver and decreased in bone marrow and thymus. The later phase was characterized by hypertriacylglycerolaemia and a transient hypercholesterolaemia; accumulation of TG in bone marrow was the most important change, however. Changes in the lipid composition of the serum and tissues, except for an increase in TG level in thymus, returned to normal levels at the end of the observation period. Pair-feeding provided an equivalent nutritional situation in irradiated and sham-irradiated animals and thus eliminated the non-specific changes caused by different levels of food intake in both groups of animals, especially in the initial period. A sufficiently long observation period is necessary for estimating the kinetics of metabolic changes in rats exposed to non-lethal doses of X-irradiation.

Adipose Tissue↗
PubMed1980

Circadian rhythm of serum and tissue lipids in fed and fasted rats.

The oscillations of the free fatty acid concentration in the serum and white (epididymal) adipose tissue, of triglycerides in the serum and liver, of total serum, liver and adrenal cholesterol and of serum phospholipids were studied at 3-hour intervals for a period of 24 hours in fed male Wistar rats and in animals fasted for 24 hours (both adapted to an illumination regimen of 12 hours' light and 12 hours' darkness. The rhythm--studied by means of the cosinor analysis--was present in most of the given parameters; it was not recorded in the liver triglycerides and serum phospholipids of fasted rats and in the adrenal cholesterol of fed animals. Apart from the circadian rhythm, many parameters distinctly displayed an ultradian rhythm, mainly an approximately 12-hour period. In general, one day's starvation did not significantly affect the course of the circadian oscillations of the given indicators of rat lipid metabolism.

Animals↗
PubMed1980

Changes in lipoprotein lipase activity in the adipose tissue, heart and liver of continuously irradiated rats.

Adult male Wistar rats were continuously irradiated for 30 days on an experimental field from a 60Co source or radiation. Lipoprotein lipase activity was determined in their adipose tissue, heart and liver at intervals of 1, 3, 7, 14, 21 and 30 days from the beginning of irradiation and triacylglycerol, total cholesterol, phospholipid and non-esterified fatty acid concentrations were determined in their serum. Throughout the whole of the study, lipoprotein lipase activity was lower in the adipose tissue and higher in the heart of irradiated rats than in the controls. In the liver it was low 3 days from the onset of irradiation; at the other intervals it was variable and differed only non-significantly from the controls. Serum lipid concentrations were raised in irradiated rats--triacylglycerol from the 7th day, phospholipids from the 14th day and non-esterified fatty acids throughout the whole period of irradiation. In keeping with the high triacylglycerol values in the serum of irradiated rats, lipoprotein lipase activity in their adipose tissue was low.

Adipose Tissue↗
PubMed1980

Lipid mobilization and lipolysis in adipose tissue of single X-irradiated rats.

Changes in both the concentration of non-esterified fatty acids in serum and white (epididymal) adipose tissue, serum glycerol, and basal and L-noradrenaline-stimulated release of NEFA and glycerol from white adipose tissue in vitro were monitored 1, 6, 24, 48 and 72 h after a single whole-body irradiation of rats with a lethal X-ray dose of 14.35 Gy (1 500R). The NEFA concentration in serum and white adipose tissue was higher 1 h after irradiation as compared with that of sham-irradiated (control) animals; the free glycerol concentration in serum of the irradiated rats was lower than that of control rats. Basal release of NEFA was higher 1 h after irradiation, and lower 6 and 72 h after irradiation; the simulated release of NEFA did not change significantly. Basal and stimulated release of glycerol from the adipose tissue of irradiated rats was higher 6 h after irradiation. The relation between the changes in lipolysis and lipid mobilization and the changes in serum and tissue lipids in the irradiated organisms are discussed.

Adipose Tissue↗