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Biomedical subjects

V Djordjevic

Publications and source records attributed to V Djordjevic.

17 recordsLinked to original sources
PubMed2006

PCR amplification on whole blood samples treated with different commonly used anticoagulants.

The aim of this study was to explore the influence of different anticoagulants on PCR amplification, as well as to optimize PCR amplification of blood samples for successful mutation detection. For the purpose of this study the amplification of part of methylenetetrahydrofolate reductase (MTHFR) gene exon 4, in which mutation C677T is located, was performed. With the exception of sodium heparin, the presence of other commonly used anticoagulants (sodium citrate, K3EDTA, lithium heparin) made it possible to obtain satisfactory amplification. The described method, apart from saving time and material, enables successful PCR-based analysis even when a very small amount of blood sample is available.

Anticoagulants↗
PubMed2005

Lymphocyte PC-1 activity in patients on maintenance haemodialysis treated with human erythropoietin and 1-alpha-D3.

BACKGROUND: Plasma cell differentiation antigen 1 (PC-1) is an inhibitor of insulinreceptor tyrosine-kinase. PC-1 content is elevated in muscle and adipose tissue from insulin-resistant subjects and its elevation correlates with in vivo insulin resistance. It is known that insulin resistance in uraemia may be improved with erythropoietin (EPO) and vitamin D therapy. Therefore, in this study the effects of human recombinant EPO and 1-alpha-D3 treatments on lymphocyte PC-1 expression in patients with end-stage renal failure on haemodialysis (HD) were investigated. METHODS: Lymphocyte basal, concanavalin A (Con A), and phorbol-12-myristate13-acetate (PMA)-stimulated PC-1 activity were investigated in HD patients before and after a two-month treatment with subcutaneous EPO (15 patients, 2000-3000 U thrice weekly) or oral 1-alpha-D3 (14 patients, 2 mug thrice weekly). Twenty-nine patients (16 men and 13 women), aged 22-68 years (49+/-7 years), on HD from 13 to 112 months, and 30 healthy controls participated in the study. None was obese and all had normal fasting plasma glucose. RESULTS: A two-month EPO treatment produced a 41% haematocrit increase, with a rise in haemoglobin from 6.51+/-0.18 g/dL to 9.69+/-0.14 g/dL. Basal lymphocyte PC-1 activity in HD patients was found to be significantly increased (P<0.005) over the level in healthy controls. Treatment of patients with EPO decreased unstimulated lymphocyte PC-1 activity to values significantly lower than before the treatment (P<0.001). Lymphocyte Con A and PMA-stimulated PC-1 activity in patients on HD was found to be slightly increased over the level in healthy controls, but significantly reduced (P<0.005 and 0.05, respectively) after the EPO treatment. A two-month pulse oral 1-alpha-D3 treatment increased haematocrit by 21% and raised haemoglobin from 7.11+/-0.32 g/dL to 8.80+/-0.39 g/dL. This treatment normalized serum alkaline phosphatase activity and slightly reduced serum parathyroid hormone concentration. PC-1 in unstimulated and PMA-stimulated lymphocytes was unchanged, but significantly decreased (P<0.05) in Con A-stimulated lymphocytes after 1-alpha-D3 treatment. Fasting plasma glucose was not changed by the treatment. CONCLUSION: An increased lymphocyte PC-1 activity over control was found in HD patients. A two-month EPO therapy significantly decreased PC-1 activity to the control values, suggesting that an effect on PC-1 expression could be implicated in the amelioration of insulin resistance in uraemic patients treated with EPO. Treatment with pulse oral 1-alpha-D3 had an effect only on PC-1 of Con A-transformed lymphocytes of haemodialysed patients and requires further investigation.

Adjuvants, Immunologic↗
PubMed2004

Acute panmyelosis with myelofibrosis: clinical, immunophenotypic and cytogenetic study of twelve cases.

The clinical, cytogenetic, and immunophenotypic features in 12 adult patients with acute panmyelosis with myelofibrosis (APMF; ICD-0-3: 9931/3; C42.1) are reported (median age: 57 years; f/m = 1.4). The white cell count (WBC) was normal in 3 patients; 9 had leucopenia. The median hemoglobin value was 64.5 g/l, and median platelet count 12 x 10(9)/l. Bone marrow biopsy showed a hypercellular marrow in 10/12 patients with a significant infiltration of pathological blasts (range: 30 - 60%). All the cases had marked reticulin fibrosis. Immunophenotyping of bone marrow blast cells showed the expression of early (CD34) and lineage-unspecified antigens (HLA-DR) in 6/7, and 7/7 patients, respectively. "Early" myeloid antigens (CD13, CD33) were seen in 6/7 and 4/6 patients respectively. Monocyte antigen (CD14) was expressed in 3/7 patients. Megakaryocyte antigen (CD61) and erythroid cell antigen (GpA) were each expressed in only 1 patient. Two patients had expression of CD34, HLA-DR and "early" myeloid antigens by their bone marrow blast cells and 1 of these also had a co-expression of the antigens from a differentiated monocytic cell proliferation (lysozyme+, CD68+). Nonspecific chromosomal aberrations were recorded in 8/10 patients. The median survival was 2 months. These findings suggest an immature myeloid phenotype of blast cells in APMF. In 6/9 patients a leukemic cell differentiation into monocytic, megakaryocytic or erythroid lineage was also demonstrated.

Adolescent↗
PubMed2004

Stomal recurrence after primary total laryngectomy.

Stomal recurrence after total laryngectomy is usually considered to be incurable. A total of 402 patients suffering from squamous cell carcinoma of the larynx treated by total laryngectomy during the period 1982-96 were analysed. In the group of patients studied, the significant risk factors for stomal recurrence were glottic-subglottic tumour localization and regional tumour spread. Postoperative radiotherapy can significantly reduce the risk of stomal recurrence.

Carcinoma, Squamous Cell↗
PubMed2002

Nephroprotective effects of pentoxifylline in experimental myoglobinuric acute renal failure.

The nephroprotective effects of pentoxifylline, a methylxantine, were studied in glycerol-induced acute renal failure. Glycerol treated rats exhibited collecting duct and medullary ascending limb dilation and casts, with focal tubular damage, confined mainly to the superficial cortex. In the interstitium focal mononuclear infiltration was observed. In some glomeruli there was swelling of mesangial spaces and mesangial cells. Pentoxifylline injected to glycerol pretreated rats exerted a protective effect. Only few groups of proximal tubules in the subcapsulary region of renal cortex showed necrosis and tubulorhexis. There were not leukocyte infiltrations or vascular congestion. Morphometric analysis showed increased surface area fraction of tubular lumen in rats treated with glycerol (p < 0.01) compared to those in controls. Intratubular cast formations in rats treated with glycerol alone were significantly higher than in rats given pentoxifylline in addition to glycerol. Kidney cortex ectopeptidases (APA, APN and DPP IV) were not significantly changed after glycerol administration. Serum creatinine and blood urea were markedly increased in glycerol treated rats, however, pentoxifylline reduced significantly their levels. This study in glycerol-induced acute renal failure showed a marked renal morphologic and functional protection by pentoxifylline.

Acute Kidney Injury↗
PubMed2002

Antioxidants modulate adenosine metabolism in rat mesangial cells cultured under high glucose conditions.

Glomerular mesangial cells play a major role in glomerular hemodynamics, considered also as antigen-presenting cells participating in immune response. Mesangial dysfunction and proliferation are typical lesions of diabetic glomerulopathy. Adenosine, a local hormone, produced by mesangial cells is a metabolic regulator of renal blood flow, capable of decreasing glomerular filtration rate (GFR), exerting immunosuppressive, antiproliferative and anti-inflammatory properties. Since it was well established that antioxidants confer protection against increased oxidative stress that occurs in diabetes, the effect of captopril, reduced glutathione and melatonin on adenosine metabolism was investigated. Glomerular mesangial cells obtained from collagenase treated glomeruli, isolated from renal cortex of Sprague-Dowley rats, were grown under high glucose conditions (30 mmol/L) as a model of diabetic microenvironment. The activity of adenosine metabolizing enzymes: 5'-nucleotidease (5'-NU) responsible for its production and adenosine deaminase (ADA) responsible for its degradation were investigated. Hyperglycemic conditions led to decreased adenosine production via 5'-NU and decreased removal via ADA. Captopril, given in therapeutic concentration induced enzyme activities in normoglycemic conditions and restored hyperglycemia-induced decrease. In order to investigate if the presence of SH groups may be responsible for this improvement, the cells were exposed to reduced glutathione, and it exerted almost equal effect, given in physiological and higher concentrations. Melatonin increased 5'-NU activity only in physiological glucose conditions. Presented results confirm potential renoprotective effect of SH-group containing antioxidant supplementation during diabetes in restoring adenosine metabolism.

Adenosine↗
PubMed2001

Oxidative modification of rat liver 5'-nucleotidase: the mechanisms for protection and re-activation.

The effect of oxidative stress catalysed by transition metals appears to have a critical relevance for the structure and function not only of membrane lipids but also of integral membrane proteins in a complex lipid-protein assembling, and membrane-dependent function. The integral membrane enzyme 5'-nucleotidase is susceptible to Fe((2+))-ion catalysed oxidative modification, and the extent of enzyme inhibition is in inverse relationship (r = -0.820) with lipid peroxidation (MDA) level. This work is also a comparative study about possible effectiveness of different Fe-ion chelators (deferoxamine, Na-citrate, Na-salicylate, ammonium oxalate and EDTA), antioxidants (GSH, GSH/GSH-Px system, Cu, Zn-SOD and mannitol) and metal cations (Mg(2+) and Mn(2+)) to protect or restore Fe(2+)-ion induced 5'-nucleotidase inhibition and to suppress Fe(2+)-ion enhanced lipid peroxidation. Among the examined chelators it was only deferoxamine and Na-citrate that exerted a fully protective and reactivating ability; among the antioxidants it was only GSH; among the metal cations it was only Mn(2+). The ability to protect or restore 5'-nucleotidase activity and to diminish chain-induced lipid peroxidation is explicable in terms of: metal-binding ability, capacity of taking iron away from a biological molecule, or ability of transferring the damage to itself. After a short incubation period, the iron associated with enzyme or lipid hydroperoxides could be in a labile coordinative linkage, still able to interact with possible ligands or metal cations.

5'-Nucleotidase↗
PubMed2001

Method for the measurement of antioxidant activity in human fluids.

AIM: To develop a new, simple, and cheap method for estimating antioxidant activity in human fluids. METHODS: The assay measured the capacity of the biological fluids to inhibit the production of thiobarbituric acid reactive substances (TBARS) from sodium benzoate under the influence of the free oxygen radicals derived from Fenton's reaction. A solution of 1 mmol/litre uric acid was used as standard. RESULTS: The following mean (SD) antioxidative activities were found (as uric acid) in the various biological fluids: serum, 2.04 (0.20) mmol/litre; urine, 176.5 (25.6) micromol/litre; cerebrospinal fluid, 95.0 (26.9) micromol/litre; aqueous humour oculi, 61.25 (9.9) micromol/litre; saliva, 838.5 (48.2) micromol/litre; tears, 247.0 (17.0) micromol/litre; ascites fluid, 270.0 (63.3) micromol/litre; kidney cyst fluid, 387.1 (28.1) micromol/litre. Small samples of the biological material were needed for the analyses: 10 microl of serum and 50-100 microl of other body fluids. In the sera of 48 healthy individuals there was a significant positive correlation between values obtained with the Randox method (as a reference method) and the new method proposed here (correlation coefficient, 0.8728; mean difference between methods, <0.4%). CONCLUSIONS: This method is easy, rapid, reliable, and practical for the routine measurement of total antioxidant activity in serum and other human body fluids. Small samples of biological material are needed for the analyses and the results are comparable with the reference (Randox) method.

Antioxidants↗
PubMed2000

Additional chromosome aberrations in acute promyelocytic leukemia: characteristics and prognostic influence.

Patients with acute promyelocytic leukemia (APL) show other chromosome aberrations in addition to t(15;17) but their influence on the clinical outcome is still unclear. We have cytogeneticaly analyzed 43 APL patients with t(15;17)(q22;q21), treated with all-trans-retinoic acid (ATRA) according to the recommendations of the European APL 91 Group. Additional chromosome aberrations were observed in 14/43 patients (33%) studied at initial diagnosis. These patients were designed as 'complex' karyotype group and were compared to patients with t(15;17) asa sole cytogenetic abnormality ('simple' karyotype group). The 'complex' group had significantly lower platelet count and fibrinogen level and fewer cases without significant DIC at diagnosis than the 'simple' group. Comparison of 'simple' and 'complex' groups showed significant difference in complete remission rate (76% vs 35.7%, P = 0.0148) and early death rate (24% vs 64.3%, P = 0.0141). Survival analysis showed that the presence of additional chromosome abnormalities and significant DIC had an adverse effects on prognosis (P = 0.036 and P = 0.041, respectively), independent on other prognostic factors. These data indicate more aggressive biological nature of leukemic cells in patients with additional chromosome aberrations. Supplementary therapeutic strategies may be required for this subgroup of APL patients.

Adolescent↗
PubMed2000

Effect of steroid hormone deprivation on the expression of ecto-ATPase in distinct brain regions of female rats.

Abundant evidence indicates that ATP and adenosine act as neurotransmitters or co-transmitters, influencing nerve cell physiology in various ways. Therefore, regulation of ATP-metabolizing enzymes is essential for the normal development and function of neuronal tissue. In the present study we have examined the effect of gonadal (OVX) or adrenal (ADX) steroid hormone deprivation on the activity and expression of synaptic membrane ecto-ATPase in three extrahypothalamic brain areas of female rats, primarily not associated with reproductive function. It was shown that OVX significantly increased ecto-ATPase activity and the relative abundance of this enzyme in the hippocampal (Hip) and caudate nucleus (CN), but not in brain stem (BS) membrane preparations. ADX was followed by an upregulation of the enzyme activity and its relative abundance in all the brain areas investigated. The highest enzyme activity and the most profound effects of OVX and ADX were detected in the CN. The results obtained indicate that ADX and OVX upregulate the expression of ecto-ATPase, potentiating the production of adenosine in synaptic cleft thus modulating the activity of numerous neurotransmitter systems in distinct areas of the CNS.

Adenosine Triphosphatases↗
PubMed1997

Serum levels of some acute phase proteins in kidney and urinary tract urothelial cancers.

Early diagnosis of kidney and urothelial cancer requires some new sensitive and specific methods. In this study the diagnostic use of serum alpha 1-acid glycoprotein (alpha 1-AG), coeruloplasmin, alpha 1-antitrypsin (alpha 1-AT), alpha 2-macroglobulin (alpha 2-MG) and albumin in patients with kidney, urinary bladder and upper tract urothelial cancer was evaluated. In kidney cancer patients the serum levels of alpha 1-AG, coeruloplasmin and alpha 1-AT were significantly increased over the controls (p < 0.001), however, albumin was decreased (p < 0.005). Sensitivity was relatively high for alpha 1-AG (85%), albumin (85%) and alpha 1-AT (77%). In patients with urinary tract urothelial cancer alpha 1-AG, alpha 1-AT and coeruloplasmin were also increased but not as much as in kidney cancer. Sensitivity of alpha 1-AG (63%), albumin (75%) and alpha 1-AT (66%) was also lower than in kidney cancer. This study has established the relative importance of alpha 1-AT and albumin determination in patients with kidney as well as with urothelial cancer.

Acute-Phase Proteins↗