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Biomedical subjects

N Kovacević

Publications and source records attributed to N Kovacević.

At least 19 recordsLinked to original sources
PubMed2005

Free radical scavenging activity of Achillea alexandri-regis extracts.

The antioxidative potential of Achillea alexandri-regis has been studied by measuring the influence of herb extracts on hydroxyl and superoxide radicals' quantity in different in vitro systems. The ethyl acetate extract exhibited hydroxyl radical scavenging activity in all tested biological system (liver homogenate, hemolyzed blood, serum and postmitochondrial liver fraction), whereas butanol extract reduced hydroxyl radicals significantly only in the postmitochondrial liver fraction. Both extracts showed superoxide radical scavenging effect only in hemolyzed blood.

Achillea↗
PubMed2005

Cytotoxic and antioxidant activity of Achillea alexandri-regis.

The cytotoxicity and antioxidant properties of herb extracts of Achillea alexandri-regis were studied. Combined chloroform and ethylacetate extracts exhibited a pronounced cytotoxic effect against HeLa cancer cells (IC50 = 25.92 +/- 4.96 microg/ml), and lower cytotoxicity against K562 leukemia cells (IC50 = 48.59 +/- 18.31 microg/ml). The methanol extract was found to be a moderately cytotoxic in vitro agent against HeLa and K562 cells. No suppressive activity was detected on non-malignant peripheral blood mononuclear cells (PBMC). The antioxidant activity of the methanol extract was assessed by DPPH radical scavenging. The methanol extract of A. alexandri-regis showed concentration dependent DPPH radical scavenging activity with IC50 = 36.14 +/- 0.05 microg/ml.

Achillea↗
PubMed2004

A three-dimensional MRI atlas of the mouse brain with estimates of the average and variability.

Although there is growing interest in finding mouse models of human disease, no technique for quickly and quantitatively determining anatomical mutants currently exists. Magnetic resonance imaging (MRI) is ideally suited to probe fine structures in mice. This technology is three-dimensional, non-destructive and rapid compared to histopathology; hence MRI scientists have been able to create detailed three-dimensional images of 60 mum resolution or better. The data is digital which lends itself to sophisticated image processing algorithms. Here we show a variational MRI atlas constructed from nine excised brains of 8 week old 129S1/SvImJ male mice. This new type of atlas is comprised of an unbiased average brain--created from alignment of the individual brains--and the mathematical descriptors of anatomical variation across the individuals. We found that the majority of internal points in the individuals never varied more than 117 microm from equivalent points in the atlas. A three-dimensional annotation of the average image was performed and used to estimate the mean and standard deviation of volumes in a variety of structures across the individual brains; these volumes never differed by more than 5%. Our results indicate that variational atlases of inbred strains represent a well-defined basis against which mutant outliers can be readily compared.

Algorithms↗
PubMed2004

[Gastrointestinal stromal tumor of small intestine--case report].

Gastrointestinal stromal tumor is a form of mesenchimal neoplasm that may be present in all parts of gastrointestinal system. We are reviewing diagnostic and therapeutic algorithms for patient with diagnosed gastrointestinal neoplasm of small intestine, experiencing repeated episodes of painful bleeding from gastrointestinal trackt.

Gastrointestinal Hemorrhage↗
PubMed2004

Quantification of allantoin in various Zea mays L. hybrids by RP-HPLC with UV detection.

A RP-HPLC method for quantification of allantoin in silk of fifteen maize hybrids (Zea mays L., Poaceae) was described. Following extraction of the plant material with an acetone-water (7:3, VN) mixture, filtration and dilution, the extracts were analyzed without previous chemical derivatization. Separation and quantification were achieved using an Alltech Econosil C18 column under isocratic conditions at 40 degrees C. The mobile phase flow (20% methanol--80% water with 5 mM sodium laurylsulfate added at pH 2.5, adjusted with 85% orthophosphoric acid; pH of water phase was finally adjusted at 6.0 by addition of triethylamine) was maintained at 1.0 mL/min. Column effluent was monitored at 235 nm. This simple procedure afforded efficient separation and quantification of allantoin in plant material, without interference of polyphenols or other plant constituents of medium to high polarity, or similar UV absorption. Our study revealed that the silk of all investigated maize hybrids could be considered relatively rich in allantoin, covering the concentration range between 215 and 289 mg per 100 g of dry plant material.

Allantoin↗
PubMed2004

Diuretic activity of Maydis stigma extract in rats.

Maydis stigma (corn silk) is a herbal drug reputed for the treatment of urinary ailments in various traditional medicine systems. To determine its influence on urinary volume and the excretion of sodium, potassium and chloride, 5% and 10% decoctions were administered daily to adult male Wistar rats for eight days. The concentration of electrolytes and urea in plasma, the influence of treatment on urinary pH value as well as creatinine clearance were also investigated. Daily oral administration of 5% decoction at the dose of 10 ml/kg led to a significant and acute diuresis in rats, reaching the peak value in the first 24 h of treatment. Over a similar period, application of 10% decoction did not affect urinary excretion of water, but significantly increased the pH value of excreted urine. A significant decrease in sodium and chloride plasma levels was observed in both treated groups. The creatinine clearance was markedly increased after the treatment with both extracts. Our findings indicate that the diuretic effect of 5% aqueous Maydis stigma extract is in accordance with the increase in glomerular filtration rate and inhibition of sodium and chloride tubular reabsorption, caused a by still unidentified intrinsic factor, but not the salt-loading effect.

Animals↗
PubMed2003

Preliminary assay on the antioxidative activity of Maydis stigma extracts.

Antioxidative effects of Maydis stigma methanolic extracts were studied on the level of lipid peroxidation in liposomes, induced by Fe(2+)/ascorbate system and measured spectrophotometrically by the TBA-test. The most significant inhibition of lipid peroxidation was observed when methanolic extracts of fully developed, mature corn silk were applied. The same test, performed after fractionation of the most active extract, showed that most of the activity was concentrated in fractions with moderate lipophilicity, containing phenolic acids, flavonoid aglyca and resembling monosides.

Antioxidants↗
PubMed2003

Preliminary assay on the antioxidative activity of Laurus nobilis extracts.

Antioxidative activity of Laurus nobilis leaves, bark and fruit methanolic extracts (crude and defatted) were studied on the level of lipid peroxidation in liposomes, induced by Fe(2+)/ascorbate system and measured spectrophotometrically by the TBA-test. The most significant inhibition of lipid peroxidation was obtained with methanolic extracts of laurel bark (70.6% of inhibition was obtained with 1.0 mg of crude extract).

Antioxidants↗
PubMed2001

[Topographic and structural characteristics of the minor duodenal papilla].

The study of minor duodenal papilla topography and structure was carried out on 36 fresh autopsy specimens of human duodenopancreas. We performed precise measurements of its distance to the major duodenal papilla and to the superior duodenal flexure. There was no correlation between the position of the minor papilla and the incidence of duodenal ulcer disease. Microdissection and histological staining of the minor papilla did not reveal an anatomically defined sphincter around the terminal portion of the accessory pancreatic duct. All the specimens of the minor papilla contained within acini of pancreatic tissue. A terminal dilation of the accessory pancreatic duct was found in 22% of the cases.

Adult↗
PubMed1998

[Surgical treatment of liver metastases of colorectal carcinoma].

Colorectal carcinoma metastasizes into the liver, but liver-only metastases are infrequent. Liver-only metastases are seen mainly from colorectal carcinoma. This is the only metastatic disease where treatment aimed only or mainly at the liver metastases is employed with curative intent. If liver resection for colorectal metastases is done by an experienced team, adhering to predefined indications, five year survival ranges from 30-40%, operative mortality is 3-5% and the postoperative morbidity is acceptable. New diagnostic techniques have been introduced and indications for liver resection extended. This paper presents the current limitations and possibilities for the surgical management of colorectal metastases in the liver.

Carcinoma↗
PubMed1998

A model of in vivo dosimetry and quality assurance analysis of total body irradiation in Zagreb.

The aim of the study was to develop a systemic and simple method for determination of midplane dose factors and lung correction factors, suitable for semiconductor 60-Co total body irradiation (TBI) in vivo dosimetry, based on input (entrance) and output (exit) dose readings. A theoretical model of anthropomorphic phantoms of cylindrical ellipsoid shape made it possible to generalize the applicability to any individual case of the real patient's data. Also, the quality assurance analysis of dosimetric results of 230 patients who had undergone TBI during a 10-year period, was performed. The ratio of the mean measured dose values for all locations in all patients and stated dose (12.45 Gy in 3 days, 3 fractions) was 0.998, SD 0.033. The upper limit of the total combined uncertainty of TBI midplane absorbed dose, including all locations and all sources of error, amounted to 9.4%.

Humans↗
PubMed1995

[Gallbladder motor function studied by modified infusion cholescintigraphy method after gastric and duodenal surgery].

Estimation of the gallbladder (GB) motility disorders after gastric surgery has not yet been assessed because of the shortage of the reliable diagnostic methods. The aim of the study is introduction, modification and establishment of the infusion cholescintigraphy into clinical practice and its performance in the groups of patients with gastric resection (RVBI i RVBII), total gastrectomy and patients after gastroplasty. Obtained data produced information about motility disorders caused by billateral truncal vagotomy, lack of the food transit through duodenum and if the motility disorders are the same in different time periods after operation. In groups of patients without truncal vagotomy (RVBI and RVBII), minor motility disorders are registered in comparison to the groups after truncal vagotomy. In the period of 6 months after surgery, higher motility disorders are registered in the group of patients with total gastrectomy, while after 9-12 months GB motility completely recovers. Groups with preserved transit of food through duodenum (RVBI and gastroplasty), has minor motility disorders in comparison to the group without transit of food through duodenum (RVBII and total gastrectomy). By introducing infusion cholescintigraphy, reliable method for the GB motility assessment is obtained.

Adult↗