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Diabetes damages tissues mainly through non-enzymatic glycosylation and free radical oxidation of cellular constituents. This study was designed to determine the combined effect of melatonin and streptozotocin (STZ)-induced diabetes in... more
Diabetes damages tissues mainly through non-enzymatic glycosylation and free radical oxidation of cellular constituents. This study was designed to determine the combined effect of melatonin and streptozotocin (STZ)-induced diabetes in rats on the structural stability of spectrin, the main cytoskeletal protein of erythrocytes. Diabetes was induced by a single injection of STZ (60 mg/kg, i.p.). Melatonin is strong antioxidant that does not prevent glycosylation of proteins. It was administered to the rats (10 mg/kg, i.p.) for 7 consecutive days after the inducement of diabetes. Wistar male rats were divided into three groups: control (n = 6), untreated-diabetic (n = 5), and melatonin-treated diabetic (n = 5). On the 42th day after STZ injection, the animals were anesthetized with Nembutal (50 mg/kg i.p.) and exsanguinated, about 1 ml heparinized blood were taken and washed with 9 ml of 150 mM NaCl. 50 μl of washed erythrocytes were suspended in 150 mM NaCl, hematocrit 0.50, and heate...
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Ionizing radiation in radiotherapy can disrupt cellular functions based on radiation type, energy, and dose. However, investigations on the effects of accelerated electrons, particularly on serotonin mediation, are limited. This study... more
Ionizing radiation in radiotherapy can disrupt cellular functions based on radiation type, energy, and dose. However, investigations on the effects of accelerated electrons, particularly on serotonin mediation, are limited. This study aimed to investigate changes in serotonin signal transduction (targeting 5-HT2A and 5-HT2B receptors) in gastric smooth muscle (SM) samples isolated from rats irradiated with accelerated electrons (linear accelerator Siemens Primus S/N 3561) and their effects on serotonin-induced reactions. The radiation effects were examined in samples prepared five days after the procedure. The contractile activity of smooth muscle samples was measured using an isometric method. The expression of 5-HT2A and 5-HT2B receptors was determined by immunohistochemical assay. Increased contractile reactivity to exogenous serotonin (1.10−8–1.10−4 mol/L) was observed in irradiated samples compared to controls. The expression of 5-HT2A and 5-HT2B receptors was significantly inc...
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Evidence has accumulated that the pathology of CoViD-19 is strongly related to the renin-angiotensin system (RAS). The blockage of the angiotensin converting enzyme 2 (ACE2) by the SARS-CoV-2 virus leads to downstream consequences such as... more
Evidence has accumulated that the pathology of CoViD-19 is strongly related to the renin-angiotensin system (RAS). The blockage of the angiotensin converting enzyme 2 (ACE2) by the SARS-CoV-2 virus leads to downstream consequences such as increased vascular tone, extensive fibrosis and pronounced immune reactions. Different approaches to tackle the adverse viral effects by compensating the lost ACE2 function have been suggested. Here, we use an unequal-arm lever model to describe a simplified version of the biased regulation exercised by the angiotensin II and angiotensin-(1-7) hormones, which are the substrate and the product of ACE2, respectively. We reason upon the lever dynamics and its disruptions caused by the virus, and propose that a combination of RAS modulators will most efficiently compensate the imbalance due to the excess of angiotensin II and the scarcity of angiotensin-(1-7). Specifically, we focus on the possible benefits of the simultaneous application of two agents, a MAS-receptor agonist and an angiotensin-II-type-2-receptor agonist. We conjecture that this combination has the potential to introduce a beneficial synergistic action that promotes anti-hypoxic, anti-fibrotic and anti-proliferative effects, thereby improving the clinical management of acute and chronic CoViD-19 pathologies.
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This is an in vivo study detailing the effects of catalase (CAT), superoxide dismutase (SOD) and the level of lipid peroxidation (LPO) products in liver homogenates from mice treated with alpha amanitin or phalloidin. Spectrophotometry... more
This is an in vivo study detailing the effects of catalase (CAT), superoxide dismutase (SOD) and the level of lipid peroxidation (LPO) products in liver homogenates from mice treated with alpha amanitin or phalloidin. Spectrophotometry was the main method used in this study. Our results showed that both toxins increased SOD activity, confirming an earlier in vitro study. In addition, our present study showed that alpha amanitin inhibited CAT activity and showed prooxidant properties, while phallodin showed an increase in CAT activity, which confirmed its in vivo antioxidant properties.
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The mathematical model (MM) of plasma renin activity (PRA) changes is offered. The modeling was based on the estimation of studied parameter changes after applying impulse input influence. The experiment was carried out on 126 male white... more
The mathematical model (MM) of plasma renin activity (PRA) changes is offered. The modeling was based on the estimation of studied parameter changes after applying impulse input influence. The experiment was carried out on 126 male white rats. Nifedipine was given in doses 20 and 40 mg/kg and PRA was measured at 30-th min., 1, 3, 5 и 7-th hour. For the purpose of the mathematical model it was assumed that the treatment with nifedipine was similar to applying impulse Dirac function. The results were interpolated to obtain weight transient function W(t) using computer program KORELIA. Concentration transition function h(t) was obtained after integration. The curves h(t) was necessary to evaluate the characteristics of the PRA: steady state level and settling time. The function h(t) in both cases respond to self regulation system described by differential equation of first range.
The significance of AT 1 and AT 2 receptor subtypes for the development of Angiotensin II (Ang II)-induced contractions of different intestinal segments was investigated. Longitudinal strips from rat jejunum, ileum, colon and rec-tum were... more
The significance of AT 1 and AT 2 receptor subtypes for the development of Angiotensin II (Ang II)-induced contractions of different intestinal segments was investigated. Longitudinal strips from rat jejunum, ileum, colon and rec-tum were prepared and treated by Ang II in a dose of 1 µM. The specific effects on Ang II receptors were studied by pretreatment with the selective AT 1 antagonist Losartan (100 nM) or AT 2 receptor blocker PD 123319 (100 nM). The recorded force vs. time curves of smooth muscle contractions were explored by calculation of amplitudes, integral force, the power of the contraction, as well as time parameter analysis. The application of Losartan caused significant reduction of the amplitude of smooth muscle contraction of preparations from colon and rectum (2.53±0.12 g and 2.79±0.25 g, respectively) in comparison to those provoked with Ang II alone (3.43 ± 0.38 g and 4.74 ± 0.44 g). The blockade of AT 1 receptors completely neutralized Ang II-provoked jejunal a...
ABSTRACT Export Date: 18 October 2014
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This study was carried out to investigate possible protection effect of 1-ethyl-3-[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)]-1-nitrosourea (SLENU), synthesized in our laboratory, against oxidative liver injuries induced in mice treated by... more
This study was carried out to investigate possible protection effect of 1-ethyl-3-[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)]-1-nitrosourea (SLENU), synthesized in our laboratory, against oxidative liver injuries induced in mice treated by antitumor drugs: doxorubicin (DOX), bleomycin (BLM), or gamma irradiation (R). Specifically, alterations in some biomarkers of oxidative stress, such as lipid peroxidation products measured as malondialdehyde (MDA) levels and activities of the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), were studied in liver homogenates isolated from tumor bearing C57 black mice after i.p. treatment with solutions of DOX (60 mg/kg), BLM (60 mg/kg), or after total body gamma-irradiation with a single dose of 5 Gy. The same biomarkers were also measured after i.p. pretreatment of mice with SLENU (100 mg/kg). Statistical significant increased MDA levels and SOD and CAT enzymes activities were found in the liver homogenates of tumor bearing mice...
Research Interests: Pharmacology, Chemistry, Oxidative Stress, Gamma Rays, Medicine, and 15 moreAntioxidants, Liver, Mice, Animals, Catalase, Superoxide Dismutase, Biomed, Lipid peroxidation, Doxorubicin, Bleomycin, Antineoplastic Agents, Drug Induced Liver Injury, Aspartate Aminotransferases, Malondialdehyde, and Alanine Transaminase
The aim of the present study was to elucidate the correlation between the Renin secretion and increased Plasma Calcium concentration and the role of Calmodulin in this process. Plasma Renin activity was determined radioimmunologically in... more
The aim of the present study was to elucidate the correlation between the Renin secretion and increased Plasma Calcium concentration and the role of Calmodulin in this process. Plasma Renin activity was determined radioimmunologically in 31 white rats, that were grouped as follows: group I - 7 controls loaded for 6 days perorally with 0.5 ml/200 g b.w. glycerin and injected i.m. for 6 days with 0.1 ml/200 g b.w. with 0.9% NaCl; group II - 8 rats, treated for 6 days with Tachistin 0.0025 mg/200 g b.w., dissolved in glycerin 0.5 ml/200 g b.w.; group III - 5 rats, treated with Tachistin 0.005 mg/200 g b.w. in the same manner; group IV - 5 rats injected i.m. with Chlorazin 0.5 mg/200 g b.w. for 6 days; group V - 6 rats, loaded with double dose Tachistin and with Chlorazin 0.5 mg/200 g b.w. for 6 days. Blood samples were taken intracardially on the seventh day from the beginning of the experiment and were analyzed with kits of Sorin-Biomedica-Italy. Our results suggest that the hypercalc...
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In order to study the effect of various agents on aldosterone secretion, the aldosterone concentration was determined radioimmunologically in 41 rats divided in groups: group I--7 rats--controls; group II--11 rats loaded p.o. with 5.5%... more
In order to study the effect of various agents on aldosterone secretion, the aldosterone concentration was determined radioimmunologically in 41 rats divided in groups: group I--7 rats--controls; group II--11 rats loaded p.o. with 5.5% glucose solution in doses of 2.4 ml/100 g body weight, taking the blood sample 2 hours after the loading; group III--7 rats subjected to the same treatment, but the blood was taken 6 hours later; group IV--7 rats subjected to hypobaric hypoxy for 2 hours; group V--9 rats treated with 40 ug/100 g b. w. actinomycin D and then subjected to hypoxy for 2 hours. The blood sample from the last two groups was taken 3 hours after the end of the hypoxy. The radioimmunological determination was made using a kit of the firm Sorin--Biomedica. The results show that glucose and hypoxy act as stimulators of aldosterone secretion.
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The aim of the present study was to investigate the role of interaction between renal nerves and nitric oxide produced by different nitric oxide synthases in the regulation of plasma renin activity (PRA) in conscious spontaneously... more
The aim of the present study was to investigate the role of interaction between renal nerves and nitric oxide produced by different nitric oxide synthases in the regulation of plasma renin activity (PRA) in conscious spontaneously hypertensive rats. Experiments were carried out on conscious normotensive Wistar rats and spontaneously hypertensive rats (SHR) with intact renal nerves and after bilateral renal denervation at age 12-14 weeks, male in sex. One day before experiments femoral artery for a direct blood pressure measurement and femoral vein for drug application were catheterized. The arterial blood pressure registration was performed during two 40 min long lasting periods: control period and 20 min after nonselective or selective neuronal nitric oxide synthase inhibition. The nonselective NO-synthase inhibition was achieved by intravenous infusion of L-NAME in dose 10 mg/kg b.w. The selective neuronal nitric oxide synthase inhibition was achieved by intravenous infusion of 7-...
Diabetes damages tissues mainly through non-enzymatic glycosylation and free radical oxidation of cellular constituents. This study was designed to determine the combined effect of melatonin and streptozotocin (STZ)-induced diabetes in... more
Diabetes damages tissues mainly through non-enzymatic glycosylation and free radical oxidation of cellular constituents. This study was designed to determine the combined effect of melatonin and streptozotocin (STZ)-induced diabetes in rats on the structural stability of spectrin, the main cytoskeletal protein of erythrocytes. Diabetes was induced by a single injection of STZ (60 mg/kg, i.p.). Melatonin is strong antioxidant that does not prevent glycosylation of proteins. It was administered to the rats (10 mg/kg, i.p.) for 7 consecutive days after the inducement of diabetes. Wistar male rats were divided into three groups: control (n = 6), untreated-diabetic (n = 5), and melatonin-treated diabetic (n = 5). On the 42th day after STZ injection, the animals were anesthetized with Nembutal (50 mg/kg i.p.) and exsanguinated, about 1 ml heparinized blood were taken and washed with 9 ml of 150 mM NaCl. 50 μl of washed erythrocytes were suspended in 150 mM NaCl, hematocrit 0.50, and heate...
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... 2 203 MODEL OF A PLASMA RENIN ACTIVITY AFTER NICARDIPINE TREATMENT Anna TOLEKOVA, Kaloyan YANKOV Thracian University, Medical Faculty Stara Zagora, Bulgaria ... 12-th Int.Conf. SAER'98. St.Konstantin resort, sept.19-20, 1998,... more
... 2 203 MODEL OF A PLASMA RENIN ACTIVITY AFTER NICARDIPINE TREATMENT Anna TOLEKOVA, Kaloyan YANKOV Thracian University, Medical Faculty Stara Zagora, Bulgaria ... 12-th Int.Conf. SAER'98. St.Konstantin resort, sept.19-20, 1998, Varna, Bulgaria,. pp.113-117. ...
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... AGAINST OXIDATIVE-HEPATIC INJURY OF ISONIAZID. Nedyalka Georgieva 1 , Vesselina Gadjeva 2* , Anna Tolekova 3. ... Clin Nephrol, 53:9-17, 2000. Czene, S., Tiback, M. and Harms-Ringdahl, M., pH-dependent DNA cleavage in permeabilized... more
... AGAINST OXIDATIVE-HEPATIC INJURY OF ISONIAZID. Nedyalka Georgieva 1 , Vesselina Gadjeva 2* , Anna Tolekova 3. ... Clin Nephrol, 53:9-17, 2000. Czene, S., Tiback, M. and Harms-Ringdahl, M., pH-dependent DNA cleavage in permeabilized human fibroblasts. ...
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The aim of this study was to analyze in detail and to compare the effects of angiotensin II (ang II) and arginine -vaso-pressin (avP) on the contractile activity of smooth muscle strips from different rat gastrointestinal segments by... more
The aim of this study was to analyze in detail and to compare the effects of angiotensin II (ang II) and arginine -vaso-pressin (avP) on the contractile activity of smooth muscle strips from different rat gastrointestinal segments by application of time-parameter analysis. longitudinal muscle strips from the rat stomach and intestine were used for in vitro recording of contraction, iduced by ang II (10 -6
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In recent years, many authors have investigated the possible antidiabetic effect of lactic acid bacteria. Lactobacillus species constitute a major part of the lactic acid bacteria group and have been found to exhibit beneficial effects on... more
In recent years, many authors have investigated the possible antidiabetic effect of lactic acid bacteria. Lactobacillus species constitute a major part of the lactic acid bacteria group and have been found to exhibit beneficial effects on the development of diabetes and its complications. In the current study, we investigated the effects of newly characterised Bulgarian Lactobacillus strains, Lactobacillus brevis 15 and Lactobacillus plantarum 13, on blood glucose levels and body weight of rats fed a fructose-enriched diet. An experiment was conducted over a period of 8 weeks with 24 2-month-old Wistar rats randomly assigned to receive a standard diet (Con, control group), fructose-enriched diet (Fr group), standard diet with probiotics given twice a week (Pro group), and fructose-enriched diet with probiotics given twice a week (Pro+Fr group). At the end of the experimental period, a statistically significant increase in body weight was observed in all experimental groups (P<0.0...
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The term probiotics derived from the Latin prefix pro which means for and the Greek noun βίος (bios) which means &quot;life&quot;. Probiotics have been defined as &quot;live microorganisms which, when administrated in adequate... more
The term probiotics derived from the Latin prefix pro which means for and the Greek noun βίος (bios) which means &quot;life&quot;. Probiotics have been defined as &quot;live microorganisms which, when administrated in adequate amounts, confer a health benefit on the host&quot;. Probiotics are commonly consumed as part of fermented foods with specially added active live cultures; such as in yogurt, soy yogurt, or as dietary supplements which causes numerous positive effects to host organisms. The pathogenesis of diabetes mellitus is complex and some of the factors implemented in it are oxidative stress and inflammation. Some probiotics have been reported to decrease the oxidative stress and to suppress the effector functions of CD4+ T cells, accompanied by reducing the pro-inflammatory molecules [1], thus having antioxidant, immune-modulatory effects and antidiabetic effects. In addition probiotics may be able to improve the lipid profile, which is the main risk factor for cardiovascular diseases (CVD) and can improve insulin sensitivity by attenuating systemic inflammation. The current review summarizes findings in the scientific literature suggesting that yogurt is a functional food that may exert antidiabetic and antioxidant properties. Interest in human microflora has only recently been emerged and it has been shown that human microflora probably has a major role in maintaining the homeostasis of human metabolism and application of probiotics is an useful approach for modulation of human microbiota. In conclusion probiotics have a lot of beneficial effects in health and disease, reducing extrinsic nuisances, modulating the immune system and improving the body antioxidant defense.
Recent studies show that human gastrointestinal microflora has a great influence over development of diabetes type II. The current review summarizes some latest data concerning the effects of the variations in gastrointestinal microbiota,... more
Recent studies show that human gastrointestinal microflora has a great influence over development of diabetes type II. The current review summarizes some latest data concerning the effects of the variations in gastrointestinal microbiota, which have both positive and negative sites in development and protection of type 2 diabetes. Recent studies have shown a relationship between the composition of the intestinal microbiota and metabolic diseases like obesity and diabetes. There is an increasing body of literature that directs the attention to a possible third culprit for development of these metabolic diseases: the gut microbiota. These microorganisms and thus their bacterial genome are increasingly considered important pathogenic factors in various diseases such as inflammatory bowel disease, obesity, diabetes etc. Three bacterial divisions, the Firmicutes (gram positive), Bacteroidetes (gram- negative) and Actinobacteria (gram positive) dominate the adult human gut microbiota. Ove...
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This study was carried out to determine the effects of 1-ethyl-3-[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)]-l-nitrosourea (SLENU), recently synthesised in our laboratory, and vitamin E as positive control on... more
This study was carried out to determine the effects of 1-ethyl-3-[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)]-l-nitrosourea (SLENU), recently synthesised in our laboratory, and vitamin E as positive control on 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) - free radical induced oxidative injuries in the liver of mice. Specifically, alterations in malonyl dialdehyde (MDA) level and activities of some antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), were measured in liver homogenates from tumour-bearing C57 black mice after treatment with solutions of CCNU (30 mg/kg) and SLENU (100 mg/kg), both administered intraperitoneally. CCNU-induced increase in MDA level, SOD and CAT activities were suppressed by SLENU. The present results and those from a previous report demonstrated superoxide scavenging activities (SSA) of the nitrosourea SLENU and enabled us explain the protective effect of the spin-labelled nitrosourea on CCNU-induced oxidative stress in the liver of mice. This protective effect is through the scavenging of *O2- and by an increased production of *NO. Thus, a potential for developing new combination chemotherapy in cancer is seen.
Research Interests: Pharmacology, Chemistry, Oxidative Stress, Medicine, Antioxidants, and 15 moreLiver, Mice, Nitric oxide, Animals, Antioxidant, Catalase, Vitamin E, Pharmazie, Superoxide Dismutase, Lipid peroxidation, Antineoplastic Agents, Drug Induced Liver Injury, Oxidation-Reduction, lomustine, and Pharmacology and pharmaceutical sciences
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Gestational diabetes mellitus (GDM) complicates 3.5% of pregnancies in England and Wales and continues to show an increase in incidence each year. GDM can lead to diabetes postpartum, it is associated with an increased perinatal risk, and... more
Gestational diabetes mellitus (GDM) complicates 3.5% of pregnancies in England and Wales and continues to show an increase in incidence each year. GDM can lead to diabetes postpartum, it is associated with an increased perinatal risk, and an increase in neonatal mortality. This review article looks at different studies regarding protein diets and their potential effects on GDM. We aimed to determine if a certain protein diet could potentially help protect against GDM using. We found that while a few studies have shown that increasing proteins in the diet of pregnant women, specifically that from poultry, whey, fish, nuts and legumes, may reduce the risk of GDM, there is certainly room for further research on the topic.
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The bones form the framework of our body. We know that bones protect our vital organs, regulate calcium and phosphorous homeostasis, and function as a site of erythropoiesis. More recently, however, the identification of bone hormones has... more
The bones form the framework of our body. We know that bones protect our vital organs, regulate calcium and phosphorous homeostasis, and function as a site of erythropoiesis. More recently, however, the identification of bone hormones has allowed us to envision bones as endocrine organs too. Within the last few years, the bone hormones osteocalcin and lipocalin 2 have been implicated with glucose and energy metabolism. We systematically reviewed articles surrounding this subject and found a clear relationship between the osteocalcin levels and glucose tolerance and insulin sensitivity. We also found that many journals have shown the detrimental effects of an absences of lipocalin 2 from adipocytes. As osteocalcin administration to mice showed decreased blood glucose levels and promoted glucose tolerance and insulin sensitivity. Future studies could perhaps explore the use of osteocalcin as a supplement for type 2 diabetes.