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Biomedical subjects

G Dashev

Publications and source records attributed to G Dashev.

At least 19 recordsLinked to original sources
PubMed1989

Streptozotocin-induced diabetes in rat. III. Antioxidant protection of vascular complications by flunarizine and aligeron.

In rats with streptozotocin-induced diabetes antioxidant protection of diabetic angiopathy was performed by flunarizine (10 mg/kg/day) and aligeron (10 mg/kg/day), applied intraperitoneally during 2.5 months of diabetes. Diabetic vascular complications were assessed by morphologic determination of PAS-positive mucopolysaccharides and measurement of vascular wall thickness in addition to quantitative estimation of lipid hydroperoxides, thromboxane A2/prostacyclin disbalance and plasma beta-thromboglobulin changes. Both drugs prevented development of diabetic angiopathy in rats by inhibition of lipid peroxidation, prostanoid synthesis and platelet activity, but the effect of flunarizine was more pronounced, which could be explained by its additional blocking effect of abnormal calcium flux into vascular cells. The free radical scavenging action of flunarizine and aligeron was investigated.

Animals↗
PubMed1988

Pathogenesis of cardiovascular disorders in streptozotocin-induced diabetes in rat. I. Cardiovascular, renal and morphologic changes in different stages of diabetes.

Some cardiovascular (heart rate and mean arterial pressure), and renal (glomerular filtration rate-GFR; renal plasma flow-RPF; filtration fraction-FF; blood urea nitrogen-BUN and albuminuria) parameters, coupled with morphologic examination, was undertaken in early (2 months) and late (6 months) stage of streptozotocin-induced diabetes mellitus in rats. The results showed a temporally (early) bradycardia and gradually increase of blood pressure with morphologic changes typical for diabetic cardiopathy. The increased GFR (by 92%), associated with significantly decreased RPF (by 37%), increased FF (by 133%), increased kidney weight/body weight ratio (by 88%), increased BUN (by 52%) and distinct albuminuria (13.53 +/- 2.08 mg/24 h/100 g b. w.), together with typical morphologic changes, suggested the development of diabetic nephropathy which was progressive with the duration of the disease.

Animals↗
PubMed1988

Streptozotocin-induced diabetes in rat. I. Influence of hypertension and myocardial infarction on the development of vascular complications.

Streptozotocin diabetes in rats was complicated by spontaneous hypertension (SHR) and myocardial infarction (MIC), considered as "risk groups". Renal function was assessed on the basis of blood urea nitrogen (BUN) and albuminuria. BUN increased by 36% in Wistar diabetic group, by 100% in SHR + diabetes, and by 51% in MIR + diabetes. Morphologic changes were assessed by estimation of PAS-positive glycosaminoglycans and measurement of vascular wall thickness of glomerular arterioles. The risk groups showed exaggerated tendency for development of diabetic angiopathy. A significant imbalance between TXA2 and prostacyclin was found, which was reflected by TXB2/6-keto-PGF1 alpha (the stable metabolites of TXA2 and prostacyclin, respectively) ratio, which increased by 38% in Wistar diabetic rats, by 61% in SHR + diabetes, and by 133% in MIR + diabetes. These changes correlated very well with increased platelet aggregability (r = 0.70; p less than 0.05) and with increased lipid peroxide level (r = 0.60; p less than 0.05), but neither with total plasma cholesterol (r = 0.20), nor with plasma triglycerides (r = 0.34). Lipid peroxides increased 5-fold in Wistar diabetic rats, 6-fold in SHR + diabetes, and 5.5-fold in MIR + diabetes. A causative relationship between TXA2/PGI2 imbalance and lipid peroxide changes on one hand, and diabetic angiopathy, on the other, was suggested.

Animals↗
PubMed1988

Streptozotocin-induced diabetes in rat. II. Lipid and lipid peroxide changes of lipoprotein fractions in diabetes complicated by hypertension and myocardial infarction.

Lipid peroxide levels and plasma lipids were studied in plasma lipoprotein fractions of streptozotocin diabetic rats, spontaneous hypertensive rats (SHR) + diabetes, and in myocardial infarction rats (MIR) + diabetes. The duration of diabetes in all experimental groups was 2.5 months. We found a tendency of elevation of cholesterol in VLDL and fall in HDL2 but the differences were not significant. Total plasma triglycerides were increased in the three diabetic groups, and the increase was due to LDL fraction but again the differences were not significant. The lipid peroxide (LP) level in total plasma showed a significant increase in the three diabetic groups: in Wistar diabetic rats LP increased 3 times, in MIR + diabetes 3.5 times, and in SHR + diabetes 5 times. The increase of LP in the three diabetic groups was due to LDL with good correlation (r = 0.60) between LP and triglycerides in LDL of the three diabetic groups. The results are in agreement with the concept of the importance of lipoprotein fraction changes: increased cholesterol, triglycerides and lipid peroxides in atherogenic (VLDL and LDL) fractions, and decreased levels in antiatherogenic (HDL, HDL2) fractions in diabetes mellitus.

Animals↗
PubMed1987

Discrepancy between aldosterone production and renin-angiotensin system activity in Brattleboro rats.

It was demonstrated before that in addition to their typical changes in water-sodium-potassium balance Brattleboro rats, homozygous for hypothalamic diabetes insipidus (DI), revealed a discrepancy between aldosterone level and plasma renin activity (PRA). In the present study PRA was significantly increased (79%), and concomitantly juxtaglomerular (JG) index was increased, reflecting an increased secretory activity of renin-producing JG cells. Plasma concentration of aldosterone was significantly lower (-36%) in DI rats than in their Long Evans (LE) controls. Adrenal blood flow rates were not significantly different in both groups of rats but aldosterone concentrations in the adrenal venous effluents were significantly lower (-66%) in DI rats than in LE rats, suggesting that in vivo production rate of aldosterone was reduced in DI rats. This assumption was confirmed by morphometric data of zona glomerulosa. Our results demonstrated a significant reduction (50%) of angiotensin II receptors in the adrenal glands of DI rats, referring to the number of binding sites and to Kd. This finding threw light on the dissociation between a decreased aldosterone production and stimulated renin-angiotensin system in DI rats.

Adrenal Glands↗
PubMed1987

Opioid peptides in experimental myocardial infarction. I. The effect of naloxone.

The effect of intravenous administration of the opioid antagonist naloxone in rats with acute left coronary artery ligation was studied. The results demonstrated that naloxone in a dose 2 mg/kg b. w. affords its protection on infarcted animals by two mechanisms: Reduces by 22% the incidence of early arrhythmias that occur within 15-20 minutes of acute myocardial ischaemia, and are responsible for the early (up to the 30th minutes) postligation death; Reverses the hypotension that results from the development of cardiogenic shock after 30 minutes myocardial infarction. The total mortality after naloxone treatment was significantly reduced by 22%. Naloxone does not influence significantly the size of the infarcted area but the incidence of left ventricle wall perforations was decreased by 38%. Both effects of naloxone are attributed to the antagonism of opioid receptors either directly on the myocardium or through blocking the central action of beta-endorphin. A direct effect of naloxone on the cardiac muscle action potential cannot be excluded.

Acid-Base Equilibrium↗
PubMed1979

[Pathomorphological studies of the testes in various forms of hypogonadism in young men].

The authors studied 32 biopsies of testes of patients, aged 18 to 26 with various forms of male hypogonadism: Klinefelter's syndrome--16, primary hypotrophy pogonadism with other known and unknown etiology--6, cryptorchism--1, secondary hypogonadism--4, later puberty--3. The materials were studied by the standard histological techniques. The authors report about definite structural changes with the various forms of hypogonadism, manifested in the elements of seminal tubules, Sertoli's cells, basal membrane of the ducts and Leydig's cells, situated in the interstitial spaces.

Adolescent↗