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Open access

I. Nikolova and N. Georgieva

Abstract

While lupin has undergone extensive research to ascertain its suitability for growth as forage or grain legume crop, the present trend is for research to be centered on its applicability in the seed protein and oil industry. Study of the literature showed that no intensive study of the lupin insect fauna had been carried out in Bulgaria. The purpose of this study was to identify the insect assemblages associated with Lupinus albus and L. luteus, as well as the insect preference for them. Thrips sampling was made by the tapping-method, aphids were directly counted on the plants and the composition and population density of other species were recorded by sweepings. Insect fauna was studied for the first time in Bulgaria. The fauna was represented on L. albus by 64 species, belonging to eight orders, 28 families and 57 genera, including 23 beetles, 25 hemipteras, five thrips, three butterflies, three bees, one leaf aphid, two grasshoppers, one leafminer and one green lacewing. L. luteus had similar species composition but was less preferred by insects. The use of lupin cultivars with shorter and intense reproductive periods, with a lower content of crude protein and phosphorus, would give an environmentally friendly protection against insect pests, which would be suitable for an organic production system.

Open access

Z. Gospodinova, N. Bózsity, M. Nikolova, M. Krasteva and I. Zupkó

Abstract

Cotinus coggygria Scop. leaf aqueous ethanolic extract was examined for its in vitro antiproliferative and antioxidant activity. Antiproliferative effect was assessed on four human gynecological cancer cell lines: breast (MCF7, T47D), cervical (HeLa) and ovarian (A2780) and compared to the cell growth inhibitory effect on non-cancerous breast epithelial cell line MCF10A using MTT cell proliferation assay. Radical scavenging assay with DPPH was applied to evaluate antioxidant potential of the extract. The obtained results showed that the herb inhibited cell growth of all of the tested cancer cell lines and the highest was the cytostatic effect on A2780 cells with a half maximal inhibitory concentration (IC50) value of 30.8 μg/ml. For the other cell lines the IC50 values were in the range of 55-122.7 μg/ml. Additionally, the extract exerted considerably weaker reduction in cell proliferation of the non-cancerous cell line MCF10A compared to cancer cells, which indicates for antiproliferative selectivity. C. coggygria extract showed high free radical scavenging activity with an IC50 value of 11.2 μg/ml. The obtained data provide evidence for pharmacological potential of the tested extract and future more detailed studies concerning the molecular mechanisms of the anticancer effect of the herb are needed.

Open access

Milena Nikolova, Mariya Petrova and Ely Zayova

Abstract

Arnica montana L. is an endangered species rich in sesquiterpene lactones, phenolic acids and flavonoids with high pharmaceutical value. The polyphenolic content and free radical scavenging activity of plants that had passed all stages of cultivation: micropropagation and rooting (in vitro), adaptation in greenhouse (ex vitro) and mountain conditions (in vivo) were evaluated. Four surface flavonoid aglycones [scutellarein 6-methyl ether (hispidulin), scutellarein 6,4’-dimethyl ether (pectolinarigenin), 6-OH luteolin 6-methyl ether and kempferol-6-methyl ether] were detected in the acetone exudates of the studied samples bymeans of thin layer chromatography.No differences in the accumulation of surface flavonoids were found among the tested leaf extracts of in vitro, ex vitro and in vivo samples. However, the extracts from the flowers were richer in surface flavonoids than extracts from the leaves. The methanol extracts of the samples from ex vitro and in vivo grown A. montana plants had significantly higher radical scavenging activity and polyphenolic content than the extracts of in vitro samples. The observed differences in the contents of these biologically active compounds were related to different growth conditions and stages of plant development. The biotechnological method of A. montana established holds promise for the future production of antioxidants.

Open access

Diana P. Karcheva-Bahchevanska, Paolina K. Lukova, Mariana M. Nikolova, Rumen D. Mladenov and Ilia N. Iliev

Abstract

Background: Vaccinium myrtillus L. is a species belonging to the genus Vaccinium of the family Ericaceae. Bilberries have drawn attention due to the multiple benefits for the human health, including antioxidant, anti-inflammatory, anticancer, anti-neurodegenerative, and cardioprotective effects. Recently, bilberries were shown to inhibit the activity of carbohydrate-hydrolysing enzymes that can help reduce the intensity of the metabolic syndrome and prevent type 2 diabetes.

Aim: In this study, we investigated the α-glucosidase and amyloglucosidase inhibitory activities of polyphenol-rich extracts from fruit of Vaccinium myrtillus L. from different regions in Bulgaria.

Materials and methods: The total phenolic content was determined spectrophotometrically using the Folin-Ciocalteu method. With HPLC analysis, phenolic acid composition of extracts was assessed. Enzymatic inhibitory activities were determined according to the methodology by Borooah et al. (1961), and Dewi et al. (2007). Amyloglucosidase assay and α-glucosidase assay were used to measure the inhibition potential of bilberries’ extracts.

Results: Phenolic compound content ranged from 1299.60 mg to 510.88 mg GAE/100 g for organic extracts and from 453.63 mg to 290.83 mg GAE/100 g for aqueous extracts. Based on qualitative HPLC analyses, gallic acid and chlorogenic acid were found to be among the major phenolic acids present in bilberries. Methanol and aqueous extracts there were found to be effective inhibitors of α-glucosidase with an IC50 value of 20 μg GAE/ml and 55 μg GAE/ml, respectively.

Conclusion: The inhibitory activity of bilberries’ extracts towards α-glucosidase offers the patients with type 2 diabetes the opportunity to manage their own glycaemic levels with a diet.

Open access

E. Nikolov, N. Nikolova and B. Grasiani

Abstract

The work proposed analytical modeling the processes in laboratory pneumatic FESTO-model. The characteristics of the pro-posed analytical model are simulated and analyzed. Systems for control of laboratory installation are synthesized. Designing control systems are modeled and their performance is analyzed. Is confirmed and proven their efficiency.

Open access

Milena Nikolova, R. Krasteva, B. Bogov, T. Tsocheva, Vi. Milenova, K. Petkov and N. Chernev

Abstract

Horseshoe kidney is an inborn renal fusion anomaly. It is frequently associated with renal stones and infections. The diagnosis is made using imaging methods - ultrasound, X-ray of the abdomen and intravenous pyelography, computed tomography (CT), magnetic resonance imaging (MRI) and radionuclide investigations. The diagnosis sometimes is hard, especially when other abnormalities are present, i.e. hydronephrosis, nephrolithiasis, stenosis of the ureteropelvic junction, etc. The authors present a male patient with horseshoe kidney and unilateral hydronephrosis due to obstruction of the ureteropelvic junction and discuss the diagnosis of horseshoe kidney and the diagnostic approach in such patients.

Open access

E. Nikolov, N. G. Nikolova and B. Grasiani

Abstract

The present study systematizes certain methods for analysis at priori un-certainty and proposes new methods for analy-sis of the filtration features of the repetitive gain scheduling control sys-tems under the conditions of periodic harmonic interference. For analysis of the fil-tering features of the repetitive gain scheduling control systems, the following methods have been proposed and applied to a particular example: temporal analy-sis with “test” periodic im-pacts in nomi-nal parametric mode and frequency analysis, using the method of the alge-braic derivative.

Open access

Kostadin N. Kichukov, Hristo V. Dimitrov, Lora K. Nikolova, Ivo S. Petrov and Maria P. Tokmakova

ABSTRACT

INTRODUCTION: Arterial hypertension is the most common chronic cardiovascular disease affecting about 25% of the adult population. Meta-analyses have demonstrated a linear relationship between blood pressure and the risk of cardiovascular events. Resistant hypertension defined as failure to reach blood pressure targets despite treatment with three antihypertensive drugs including a diuretic represents a serious clinical problem. It has been estimated that it affects between 8.9% and 12.8% of all treated hypertensive subjects. In resistant hypertension the optimal blood pressure is illusive despite very well tailored therapy.

OBJECTIVE: Management of resistant hypertension is exactly the fi eld where blood pressurecontrolling non-pharmacological methods fi t best. The present article aims at throwing light on these methods’ principles of action, on who the target patient groups are and the respective results. Two methods are especially reviewed here: the carotid barorefl ex stimulation and the transcatheter renal sympathetic denervation. Current results from the use of renal denervation suggest stable effi ciency of the method, the results becoming signifi cant 6 months after the procedure is applied and sustained for two years in the follow-up. As much as 90% of the treated patients respond to the procedure. The transcatheter renal denervation is associated with only 2.61% of procedural complications. The barorefl ex carotid stimulation, too, is known to produce a stable effect on blood pressure: the effect become obvious at 12 months in 88% of the treated subjects. The neurologic complications associated with the procedure are reported to occur in 4.4% of cases.

CONCLUSION: The present review article clearly demonstrates that non-pharmacological methods for treatment of resistant hypertension show great promise despite some open questions concerning their long term effects and procedural safety.

Open access

N. Yancheva, D. Strashimirov, I. Elenkov, T. Tchervenyakova, P. Tomova, N. Tcvetkova, M. Yankova, T. Tomov and M. Nikolova

Summary

Diarrhea is the most common gastrointestinal symptom in HIV-infected patients. The incidence and severity of diarrhea increase with progression of the immune defi ciency. In the literature, 30-60% of the patients with diarrhea among HIV-infected individuals remain without specified etiological agent. The aim of this article is to present the incidence of enterocolitis among hospitalized HIV-infected patients over a 3-year period and the degree of etiological clarifi cation of the cause. The results of our analyses showed that 63% of the hospitalized HIV-infected patients for this period were with enterocolitis. Only in 30% of these patients etiological agent was isolated. The reasons for this are mainly financial constraints and, therefore, virological investigations and further endoscopic and histopathological examination of the patients with negative for bacteria and parasites stool samples, were not performed. In the cases with isolated pathogen, an etiological treatment was carried out in parallel with highly active antiretroviral therapy, while in unsubstantiated cases an empirical treatment was carried out. Advanced immune defi ciency was associated with more severe course and worse prognosis of the enterocolitis. The treatment with highly active antiretroviral therapy, which leads to improvement of the immune status of the patients, is essential for the output of enterocolitis in HIV-infected patients.

Open access

Paolina K. Lukova, Diana P. Karcheva-Bahchevanska, Veselin P. Bivolarski, Rumen D. Mladenov, Ilia N. Iliev and Mariana M. Nikolova

Abstract

Background: Plantago major L. leaves have been used for centuries by the traditional medicine in the treatment of infectious disorders of the respiratory, urinary and digestive tracts. Researchers have reported that hot water extracts of Plantago major possess a broad-spectrum of anticancer, antioxidant and antiviral activities, as well as activities which modulate cell-mediated immunity. Their beneficial properties may be due to the significant content of polysaccharides. The polysaccharides that have been isolated from the leaves of Plantago major L. have different structures – pectic substances, galactans, arabinogalactans, glucomannans.

Aim: The aim of this paper was to study the correlation between the structure of the water extractable polysaccharides isolated from Plantago major L. leaves and their enzymatic hydrolysis with different carbohydrate hydrolases.

Materials and methods: The hydrolysis reactions were performed with the enzymes hemicellulase and mannanase. Spectrophotometric total reducing sugars assay was used to examine the hydrolysis yield. The monosaccharide and oligosaccharide compositions were determined using HPLC analysis.

Results: The highest hydrolysis yield of the water extractable polysaccharides from Plantago major leaves was obtained by treatment with hemicellulase. The hydrolysis yield increased with the augmentation of the ratio of enzyme to polysaccharide. Galactose was the prevalent monosaccharide identified in the composition of the isolated polysaccharides. Oligosaccharides with different degree of polymerization were also detected.

Conclusion: The enzymatic hydrolysis of water extractable polysaccharides from Plantago major leaves allows us to obtain different types of oligosaccharides with beneficial effects on both human health and industry.