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Biomedical subjects

A L Markel'

Publications and source records attributed to A L Markel'.

At least 37 records · Page 2Linked to original sources
PubMed2001

Iron content and parameters of blood antioxidant activity in rats with hereditary arterial hypertension during experimental myocardial infarction.

Plasma, lymph and myocardial Fe(2+) contents and blood antioxidant activity were studied in hypertensive NISAG and normotensive Wistar rats with experimental myocardial infarction. In hypertensive rats, iron levels in plasma, lymph and myocardial tissue were increased throughout the experiment. In both strains iron content in the plasma during experimental myocardial infarction negatively correlated with blood antioxidant activity. In hypertensive NISAG rats this correlation persisted also during recovery. This attests to prooxidant effect of Fe(2+) aggravating the course of myocardial infarction in NISAG rats.

Animals↗
PubMed2001

[Expression of the proopiomelanocortin gene in the hypophysis of NICAG-line hypertensive rats].

Expression of the proopiomelanocortin (POMC) gene in NISAG rats with inherited stress-induced arterial hypertension has been investigated by the reverse transcription-competitive PCR method. Normotensive rats of the inbred Wistar albino Glaxo (WAG) strain have been used as control. The effect of 3 h immobilization stress has been examined. The content of POMC mRNA in pituitaries of stressed NISAG rats exceeds that in non-stressed rats of the same strain by a factor of 2.4. Rats of the WAG strain do not demonstrate a significant increase in the level of POMC mRNA. In addition, the basIC transcription level of the POMC gene in NISAG rats is higher than in WAG ones.

Animals↗
PubMed2001

[Oxidative stress in pathogenesis of arterial hypertension in ISIAH rats].

The NO-synthase activity and the rate of NO production in the rat aortic wall and cerebellum were 2-1.5-fold higher in the ISIAH rats than in normotensive WAG rat strain. In contrast, the superoxide dismutase (SOD) activity was significantly reduced in the ISIAH rats. The blood level of reduced thiols was also much lower in the ISIAH rats. The findings suggest that oxidative stress may play a significant role in pathogenesis of stress-sensitive hypertension in the ISIAH rat strain.

Animals↗
PubMed2001

[Ultrastructural changes of kidney corpuscles in rats with hereditary stress-induced arterial hypertension].

Comparative electron microscopic study of glomerular apparatus was performed in 6-month old Wistar rats and in rat strain with inherited stress-induced arterial hypertension (ISIAH). It was shown that this stage of hypertensive status formation was characterized by hypertrophy of renal corpuscles, accompanied by structural changes of all their cellular and noncellular components. These included abrupt capillary constriction or dilation, endothelial flattening, podocyte hypertrophy and flattening of their cytopodia, thickening of basal lamina, mesangial volume expansion and increase in the number of intercapillary processes of mesangial cells. Complex of these signs suggests a disturbance of glomerular capillary blood circulation and a functional podocyte stress, compensating these microcirculatory disturbances. Changes in basal membranes and mesangium are indicative of not only increase in filtration barrier functional load, but also of initial stages of glomerular sclerosis.

Animals↗
PubMed2000

[Structural characteristics of the adrenal cortex from rats with stress-induced hereditary arterial hypertension in the late postnatal ontogenesis].

The comparative investigation of the adrenal cortex in hypertensive (INHERITED STRESS-INDUCED ARTERIAL HYPERTENSION--ISIAH) and normotensive strain (Wistar) 12-months age rats was performed. The structural signs such as the lowering of the mitochondria volume involved in steroid synthesis in showed more notable age-related reduction of steroidogenesis in the adrenal glomerular and fascicular zones and in the ISIAH rats. The lowering of the cell steroidogenesis was compensated by the adrenal glomerular and fascicular zones and hypertrophy as a result the adrenocorticocytes hyperplasia. At the same time the more considerable sclerotic changes of the adrenal cortex periendothelial space were demonstrated in the ISIAH rats. The results obtained give evidence that reducing potential of compensatory possibilities of the adrenal cortex of the ISIAH rats in the late postnatal ontogenesis period cause high probability of adaptative-compensatory mechanisms failure and pathological process aggravation in these animals.

Adrenal Cortex↗
PubMed2000

Effect of cold stress in early postnatal ontogeny on blood pressure and heart activity in normo- and hypertensive rats.

Cold stress in the early postnatal ontogeny caused permanent functional changes in the cardiovascular system, which were different in hypertensive NISAG and normotensive WAG rats. Stress led to elevation of blood pressure and overload on the left heart chambers in adult WAG rats postnatally exposed to cold. At the same time, postnatal exposure to cold stress attenuated functional disturbances typical of hypertensive NISAG rats.

Animals↗
PubMed1999

[Analysis of polymorphic DNA markers cosegregation with arterial blood pressure in ISIAH hypertensive rats].

A search for DNA markers of hereditary arterial hypertension in ISIAH rats was performed by means of contemporary molecular genetic approaches. The backcross rat population used for the analyses was derived from a cross of the Wistar x ISIAH F1 progeny with the Wistar rats. Hybridization of the HaeIII-digested DNA samples with the (CAC)5 microsatellite probe revealed cosegregation of the basal arterial pressure value with the 4.8-kb polymorphic DNA fragment. Examination of the DNA polymorphism by means of polymerase chain reaction with arbitrary primers showed an association of the 700-bp polymorphic DNA fragment with the increase of arterial blood pressure under conditions of emotional stress.

Animals↗
PubMed1999

[Metabolic damage to the myocardium in normotensive and hypertensive rats (morphometric analysis)].

Morphological changes of myocardium were demonstrated in normotensive Wistar rats and in rats with inherited stress-induced arterial hypertension 1, 7 and 30 days following adrenaline induced damage. In acute period contracture damage to cardiomyocytes was more pronounced in Wistar rats. Death of the fraction of cardiomyocytes is compensated by hypertrophy of the surviving cells already by d 7. In hypertensive rats' hypertrophied myocardium on d 1 microcirculatory bed is more impaired, while regenerative processes in cardiomyocytes are delayed and defective, which leads to dystrophy and degeneration by the end of the experiment. It is concluded that the course and prognosis of myocardial metabolic injury is determined by its initial state and potential compensatory resources.

Animals↗
PubMed1999

[Blood pressure increase in foster mothers in ISIAH and Wistar rats: effect of reciprocal cross-fostering].

Maternal arterial blood pressure (ABP) of hypertensive (ISIAH) and normotensive (Wistar) rats rearing their natural litter or litter of opposite strain, was assessed when the pups were 1.5-, 3- and 4-month old and compared with the ABP of these rats prior to their mating. The ABP was increased in both breeds of rat strains for either cross-fostered or infostered pups. No ABP changes were observed in control rats.

Animals↗
PubMed1998

[Noradrenaline synthesis during the first week of life and development of inherited stress-induced arterial hypertension in rats].

Increasing of the noradrenaline synthesis with daily i.p. administration of synthetic noradrenaline precursor DL-Threo on the 21-25th day of life of the rats with inherited stress-induced arterial hypertension (ISIAH) resulted in a drop of basal and stress-induced blood pressure in adult animals with no changes in response of the hypothalamic-pituitary-adrenocortical system (HPAS). Reduction of the noradrenaline synthesis with daily i.p. administration of dopamine-hydroxylase inhibitor FLA-57 in 21-25th day old Wistar rats induced no arterial hypertension in adults but decreased their adrenocortical response to emotional stress. Noradrenaline deficit in the brain structures on the 4th week of life in rats seems to be associated with arterial hypertension only in presence of genetic defect determining this pathology. Changes in adult HPAS function due to shortage of noradrenaline in the brain in the end of the 1st month of life do not depend on hypertension.

Animals↗
PubMed1998

[Structural features of the rat adrenal cortex with inherited stress-induced arterial hypertension in the early period of postnatal ontogenesis].

Comparative morphometric examination of adrenal cortex was carried out in 3 wks HNCAI rats with inherited stress induced arterial hypertension and normotensive Wistar rats. Relative adrenal mass, volume of cortex and its glomerular zone in HNCAI rats exceeds appropriate values in Wistar rats. Increase of adrenocorticocytes due to hyperplasia of their ultrastructural components was found. In hypertensive rats adrenocorticocyte numerical density increase due to their hyperplasia was found in adrenal fasciculate zone in contrast to glomerular one. These structural organization peculiarities in 3 wks hypertensive rat adrenal cortex reflect their elevated functional activity and may determine genetically programmed increased organism responsiveness to stress that consequently provides the grounds for the hypertensive status formation in this rat line.

Adrenal Cortex↗
PubMed1998

[The protective reaction of the myocardium to ischemic damage].

The morphological and functional consequences of epinephrine-induced myocardial infarction were studied in normo- (Wistar) and hypertensive (ISIAH) rats. After experimental myocardial infarction there was an irreversible transition to the "worn-out" stage or "plastic damage" to the myocardium. Thus, myocardial hibernation in ISIAH rats anticipates and determines the development of myocardial stunning, i.e., irreversible myocardial damage, whereas in the normotensive animals, the protective effect of hibernation is fully shown. The ontogenetic features of myocardial response of ISIAH rats to hypoxia promote transformation of adaptive hibernation and stunning to maladaptive pathological changes causing hypoxic alterations.

Animals↗
PubMed1998

[Effect of the maternal environment on blood pressure and startle reflex in rats with inherited hypertension].

In a long-term study comprising adolescence (6 weeks of age) and adulthood, acoustic startle response (ASR) and arterial blood pressure (ABP) were studied in the ISIAH (inherited stress-induced arterial hypertension) rats, in normotensive Wistar, and cross-fostered rats. The 6-week ISIAH rats already revealed a hypertension enhanced ASR as well as a reduced habituation as compared with the control rats. Maternal effects on the ASR and, to a lesser extent, on the ABP were revealed in cross-fostered rats. In young ISIAH rats fostered by Wistar surrogate mothers, the ASR was decrease and development of hypertension was delayed. There was no significant difference in expression of the ASR between adult ISIAH and Wistar rats whereas the ABP difference was quite obvious.

Animals↗