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D Djordjevic

Publications and source records attributed to D Djordjevic.

13 recordsLinked to original sources
PubMed2002

Microtiter plate assay for assessment of Listeria monocytogenes biofilm formation.

Listeria monocytogenes has the ability to form biofilms on food-processing surfaces, potentially leading to food product contamination. The objective of this research was to standardize a polyvinyl chloride (PVC) microtiter plate assay to compare the ability of L. monocytogenes strains to form biofilms. A total of 31 coded L. monocytogenes strains were grown in defined medium (modified Welshimer's broth) at 32 degrees C for 20 and 40 h in PVC microtiter plate wells. Biofilm formation was indirectly assessed by staining with 1% crystal violet and measuring crystal violet absorbance, using destaining solution. Cellular growth rates and final cell densities did not correlate with biofilm formation, indicating that differences in biofilm formation under the same environmental conditions were not due to growth rate differences. The mean biofilm production of lineage I strains was significantly greater than that observed for lineage II and lineage III strains. The results from the standardized microtiter plate biofilm assay were also compared to biofilm formation on PVC and stainless steel as assayed by quantitative epifluorescence microscopy. Results showed similar trends for the microscopic and microtiter plate assays, indicating that the PVC microtiter plate assay can be used as a rapid, simple method to screen for differences in biofilm production between strains or growth conditions prior to performing labor-intensive microscopic analyses.

Bacterial Adhesion↗
PubMed2001

Trace and major element pollution originating from coal ash suspension and transport processes.

Coal ash obtained by coal combustion in the "Nikola Tesla A" power plant in Obrenovac, near Belgrade, Yugoslavia, is mixed with water of the Sava river and transported to the dump. In order to assess pollution caused by leaching of some minor and major elements during ash transport through the pipeline, two sets of samples (six samples each) were subjected to a modified sequential extraction. The first set consisted of coal ash samples taken immediately after combustion, while the second set was obtained by extraction with river water, imitating the processes that occur in the pipeline. Samples were extracted consecutively with distilled water and a 1 M solution of KCl, pH 7, and the differences in extractability were compared in order to predict potential pollution. Considering concentrations of seven trace elements as well as five major elements in extracts from a total of 12 samples, it can be concluded that lead and cadmium do not present an environmental threat during and immediately after ash transport to the dump. Portions of zinc, nickel and chromium are released during the ash transport, and arsenic and manganese are released continuously. Copper and iron do not present an environmental threat due to element leaching during and immediately after the coal ash suspension and transport. On the contrary, these elements, as well as chromium, become concentrated during coal ash transport. Adsorbed portions of calcium, magnesium and potassium are also leached during coal ash transport.

Coal↗
PubMed1999

Combined ligation and sclerotherapy versus ligation alone for eradication of bleeding esophageal varices: a randomized and prospective trial.

BACKGROUND AND STUDY AIMS: A number of trials have been reported in which a combination of ligation and sclerotherapy was compared with ligation alone, or with sclerotherapy alone. The present trial was carried out to assess whether the combined therapy might achieve more rapid eradication of bleeding esophageal varices. PATIENTS AND METHODS: One hundred and three patients with either active bleeding or stigma of recent bleeding from esophageal varices were randomly assigned to receive ligation plus sclerotherapy, or ligation alone. Ligation was performed with the technique introduced by Stiegmann. Sclerotherapy was carried out using low-volume (1 ml) 1% aethoxysclerol, which was injected into varices proximal to each ligature. Further treatment sessions were held seven days later, and then at two-week intervals, until eradication of the varices was achieved. Endoscopic follow-up examinations were carried out at three-month intervals, or immediately if there was any recurrent bleeding. The mean follow-up period was 14 months. RESULTS: There were no significant differences between the groups of patients compared with regard to the number of sessions required to eradicate the varices (2.4 +/- 0.7 in the combined group, and 2.3 +/- 0.7 in the ligation group; p>0.05). No significant differences were found between the groups with regard to recurrent bleeding (Fp = 2.882; p > 0.05). Three cases of recurrent bleeding (6%) from treatment-induced ulcers and two cases of recurrent bleeding (4%) from duodenal ulcers were observed with the combined therapy and ligation, respectively. No significant differences in the mortality were found between the groups (Fp = 1.145; p>0.05). Two percent of patients in the ligation group died due to bacterial peritonitis. CONCLUSION: Since ligation combined with low-volume sclerotherapy did not reduce the time required for variceal eradication, it can be concluded that the combined therapy is not superior to ligation alone. This mode of endoscopic therapy for the treatment of bleeding esophageal varices is therefore not recommended.

Combined Modality Therapy↗
PubMed1998

Stimulation of immune suppressive CD34+ cells from normal bone marrow by Lewis lung carcinoma tumors.

Progressive growth of metastatic Lewis lung carcinoma (LLC-LN7) tumors is associated with increased levels of bone-marrow-derived CD34+ cells having natural suppressor (NS) activity toward T cells. The present studies determined whether tumor-derived products are responsible for this induction of NS activity. Culturing normal bone marrow cells with LLC-LN7-conditioned medium (LLC-CM) or with recombinant granulocyte/macrophage-colony-stimulating factor (GM-CSF) resulted in the appearance of NS activity. The development of NS activity coincided with a prominent increase in the levels of CD34+ cells. That the CD34+ cells were responsible for the NS activity of the bone marrow cultures containing LLC-CM was shown by the loss of NS activity when CD34+ cells were depleted. The stimulation of CD34+ NS cells by LLC-CM was attributed to tumor production of GM-CSF, since neutralization of GM-CSF within the LLC-CM reduced its capacity to increase CD34+ cell levels. Studies also showed that the induction of CD34+ NS cells by LLC-CM and GM-CSF could be overcome by including in the cultures an inducer of myeloid differentiation, 1alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3]. These results demonstrate that the mechanism by which the LLC-LN7 tumors stimulate increased levels of CD34+ NS cells from normal bone marrow is by their production of GM-CSF and that this can be blocked with the myeloid differentiation inducer 1,25(OH)2D3.

Animals↗
PubMedDate not supplied

[Neurologic manifestations after surgical interventions].

Administration of general anesthesia is rarely accompanied with newly developed postoperative neurological complications. We analyzed postoperative complications after general anesthesia where an urgent neurologic assistance was necessary. The investigation included 120 patients. The same neurologist performed neurologic examination and electroencephalography, and computerized tomography (CT) was performed if necessary. In 96 (80%) patients focal stimulative or destructive phenomena such as epi-seizures or neurologic deficit were not detected by neurologic examination. In 9 (7.5%) patients were detected consciousness crisis. In 6 patients (5%) were registered right extremities weakness with motor dysphasia, which was withdrawn in first 24 hours. In these cases EEG revealed weak activity in theta frequency, above frontoparietal regions, bilaterally. In 6 (5%) patients was registered neurologic deficit of hemiparesis or semi-severe degree with development of ischemic lesion confirmed by CT. In 6 (5%) patients, CT scan revealed the presence of mild brain edema. Also, positive correlation between duration of anesthesia, age and metabolic disorders, specially diabetes mellitus, was found. We concluded that age, type of surgical intervention and duration of general anesthesia had the greatest influence on the development of neurologic disorders during and after general anesthesia, and the presence of metabolic disorders and previous brain damage increase the risk for the onset of these complications.

Anesthesia, General↗
PubMedDate not supplied

[The closed head injury syndrome--frequency and character of brain parenchyma lesions].

The aim of this investigation was to determine the frequency and character of the brain parenchyma lesions using CT scan and MR in patients with closed head injury, and afterwards to establish the connection of those changes with clinical parameters (neurological deficit and the degree of consciousness disorder), evaluating the sensitivity and specificity of neuroradiological procedures. The investigation comprised 40 patients with closed head injury. Grade of neurological deficit (Canadian Neurological Scale) and the degree of consciousness disorder (Glasgow Coma Scale) were determined in all patients by the same neurologist. The results revealed significantly higher specificity and sensitivity of brain examination using MR in patients with closed head injury, particularly in the detection of small ischemic and contusion lesions. Likewise, the correlation of positive findings using MR was more significant concerning the grade of neurological deficit and the degree of consciousness disorder compared to the brain examination using CT scan.

Adult↗
PubMedDate not supplied

[Work capacity evaluation in workers with arterial hypertension].

The aim of this study was to show the results of working ability estimation of the workers with arterial hypertension. The estimation included 313 workers with arterial hypertension estimated by Disability Commission during 1999. Arterial hypertension was a leading diagnosis in 30.9% cause of working ability estimation. The majority of workers belonged to the 41-60 years age group and were with arterial hypertension with complications on the fundus and on the heart. In the examined group the majority of workers was declared as first category invalid (35.8%), while 32.3% of hypertensive workers had to change the working place. The majority of the first category invalids were among the hypertensive workers from textile and chemical industry, as well as among the professional drivers. The changing of the working place was more frequently suggested to the workers in textile and metal industry and in printing firms. These results could be explained by the influence of professional noxious agents on the onset and development of arterial hypertension.

Adult↗