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Biomedical subjects

J Nikolić

Publications and source records attributed to J Nikolić.

At least 19 recordsLinked to original sources
PubMed2006

Selenomethionine induces polyamine biosynthesis in regenerating rat liver tissue.

Our study was undertaken to elucidate the effects of selenomethionine (SeMet) on polyamine metabolism in regenerating rat liver tissue, as useful model of rapidly growing normal tissue. We have examined the levels of spermine, spermidine and putrescine in liver tissue. At the same time we have evaluated the activities of polyamine oxidase (PAO) and diamine oxidase (DAO), the catabolic enzymes of polyamine metabolism. The obtained results suggest that polyamine levels in regenerating liver tissue, at 7(th) day after two-thirds partial hepatectomy, were higher in comparison with control group. The administration of selenomethionine to hepatectomized animals during seven days, in a single daily dose of 2.5 microg/100 g body weight, increases the amount of spermine and spermidine; the level of putrescine does not change under the influence of SeMet in regenerating rat liver tissue.PAO activity is lower in regenerating hepatic tissue than in control group. Supplementation of hepatectomized animals with SeMet significantly decreases the activity of this enzyme. DAO activity was significantly higher in hepatectomized and in operated animals treated with SeMet compared to the sham-operated and control ones. The differential sensitivity observed in our model of highly proliferating normal tissue to SeMet, compared with the reported anticancer activity of this molecule is discussed.

Amine Oxidase (Copper-Containing)↗
PubMed1999

Morphometric and biochemical characteristics of short-term effects of ethanol on rat cardiac muscle.

Alcoholism is a very important cause of congestive cardiomyopathy in man. The aim of this study was to examine a short-term effect of ethanol in rat cardiac muscle, using histologic, morphometric and biochemical methods. Experiments were carried out in Wistar male albino rats, divided into two groups: the control group consisting of eight animals receiving tap water, and the experimental group comprising eight animals received ethyl alcohol for ten days, in a single daily dose of 3 g ethanol/kg body weight, per os, using esophageal intubation. The mean volume weighted nuclear volume of cardiac myocytes was estimated by point sampled intercept method, by objective x 100. The mean cubed nuclear intercept length was multiplied by pi and divided by 3. For biochemical analysis, a 10% water tissue homogenate from the left ventricle was made. In the experimental group, the mean volume-weighted nuclear volume (15.08 +/- 5.20 microm3) was significantly lower than in the control group (51.32 +/- 7.83 microm3) (p < 0.001). The treatment of experimental animals with ethanol caused significant increase of aldolase (p < 0.0001) and aspartate transaminase (p < 0.05) activity in the rat cardiac tissue; at the same time, the enzyme activity of creatine phosphokinase, alanine transaminase and alkaline phosphatase were not changed in the experimental group compared to the control values. The amount of the glucose in the cardiac muscle was greater in the experimental group compared to the control animals. Our results suggest that there is depression of cardiomyocyte nuclei in experimental animals treated with ethanol. Alcohol intake results in the loss of Krebs cycle enzymes and as a consequence there is greater utilization of fatty acids for energy production.

Alcoholism↗
PubMed1999

[Quality of life in patients with tumors of the upper urothelium and indications for conservative surgery].

The motives for performing conservation surgery in tumors of the upper urinary tract are progressive renal failure associated with those tumors, frequent bilateral tumors, and tumors on solitary kidney, which does not always comply with the patho-anatomic characteristics of the tumor and possibilities of this type of surgery. The aim of the study was to separate the real indications for the application of this therapy, independently of the expected quality of life after the operation. Out of 682 patients with upper urothelial tumor conservation surgery was performed in 161 patients. The indications were characterized as "real", oncologic in 121 patient, and in 40 patients (25%) the main reason was preservation of quality of life. During the five-year follow-up period recurrence developed in 17% of patients in the group with oncologic indications, "real" indications, and in as much as 40% of patients from the group in with the main reason was preservation of quality of life. Thus, the oncologic indications must be primary in reaching the decision for conservation surgery in tumors of the upper urinary tract, and the quality of life should be an additional motive for this therapy.

Aged↗
PubMed1998

Ethanol interactions with other cytochrome P450 substrates including drugs, xenobiotics, and carcinogens.

Chronic ethanol abuse is associated with increased activity of the microsomal ethanol-oxidizing system. This effect is due primarily to induction by ethanol of a specific cytochrome P450 (CYP2E1) responsible for enhanced oxidation of ethanol and other P450 substrates and, consequently, for metabolic tolerance to these substances. Furthermore, cytochrome 450 induction increases the activation of numerous xenobiotics to toxic metabolites and of chemical carcinogens to reactive metabolites, thereby accelerating their adverse effects. Microsomal enzyme induction has been associated with increased reactive oxygen species production and enhanced lipid peroxidation, as well as with decreased enzymatic and nonenzymatic scavenger activity, providing another possible explanation for ethanol-mediated toxicity. Yet another effect of chronic alcohol abuse is chronic immune system activation, which is the mechanism underlying alcohol-related liver disease. The metabolism of steroids and vitamins is catalyzed by P450 and is altered in chronic alcoholics. This article reviews recent advances in the understanding of ethanol interactions with drugs, toxic agents, and carcinogens, as well as with steroids and vitamins.

Acetaminophen↗
PubMed1996

Short-term high dose steroid therapy does not affect the hypothalamic-pituitary-adrenal axis in relapsing multiple sclerosis patients. Clinical assessment by the insulin tolerance test.

Ten patients in acute exacerbation of multiple sclerosis were treated with 1000 mg of methylprednisolone for 7 days, followed by abrupt cessation of therapy. The function of hypothalamic-pituitary-adrenal (HPA) axis was assessed by the response of ACTH and cortisol to insulin tolerance test (ITT). ITT was performed 1 day before and 1, 3, 8, 13 and 23 days after the termination of the therapy (days 0, 8, 10, 15, 20 and 30 of the study, respectively). The response of these hormones to insulin-induced hypoglycemia prior to therapy was normal. There was no suppression of the ACTH response to hypoglycemia after the methylprednisolone therapy based on the 100% rise of ACTH after ITT. Cortisol response during ITT was suppressed at day 8 (1 day after ending of therapy) but recovered on day 10 (3 days after ending of therapy). In conclusion, 7 day-therapy with 1000 mg methylprednisolone does not result in the permanent suppression of the HPA axis, suggesting that no regular supplemental corticosteroid coverage is required. The observed transitory suppression of the HPA axis recovered spontaneously after the therapy.

Adrenocorticotropic Hormone↗
PubMed1995

Myocardial catecholamines in primary heart muscle disease: fact or fancy?

The pathophysiological role of myocardial catecholamines in cardiomyopathies is still not completely understood. We there-fore assessed myocardial catecholamine concentrations (MCC) in 34 patients with hypertrophic cardiomyopathy (HCM) (76.5% males; mean age 46.7 +/- 11.6 years; left ventricular ejection fraction [LVEF] 75.3 +/- 9.8%) and in 32 patients with dilated cardiomyopathy (DCM) (87.5% males, mean age 43.1 +/- 12.5 years, LVEF 34.9 +/- 8.3%). Initial assessment included clinical work up, cardiac catheterization and endomyocardial biopsy. Myocardial norepinephrine (MNEC), epinephrine (MEC), and dopamine (MDC) concentrations in endomyocardial biopsy samples were measured using the catechol-O- methyl transferase radioenzymatic method. Significantly higher MNEC and MEC were demonstrated in HCM than in DCM patients (MNEC: 781.9 +/- 125.8 ng.g-1 fresh myocardial tissue (ft) HCM vs 262.6 +/- 68.9 ng.g-1 ft DCM, p < 0.01; and MEC: 91.6 +/- 13.9 ng.g-1 ft HCM vs 35.8 +/- 6.2 ng.g-1 ft DCM, P < 0.01). The difference in MDC did not reach statistical significance (76.1 +/- 8.3 ng.g-1 ft HCM vs 70.1 +/- 11.8 ng.g ft DCM; P > 0.05). In addition, we compared the MCC levels in 24 patients, clinically presented as dilated cardiomyopathy categorized according to the various aetiologies: 12/24 with primary DCM (75.0% males, mean age 49.6 +/- 9.5 years; LVEF 25.8 +/- 63%), 7/24 with alcohol-induced heart disease (85.7% males, mean age 46.8 +/- 7.1 years; LVEF 26.4 +/- 4.6%), and 5/24 with hypertensive heart disease (100% males, 45.1 +/- 10.6 years; LVEF 25.6 +/- 9.1%), but no significant difference was found among them (P > 0.05). There was no significant difference in tissue dopamine concentrations.

Adult↗
PubMed1995

Motor neuron disease and monoclonal gammopathy.

In a study to determine the prevalence of monoclonal gammopathy (MG) among patients with motor neuron disease (MND), 6 out of 56 (10.7%) were found to have a monoclonal paraprotein. Of these 6 patients, 4 had an IgG and 2 had an IgA paraprotein. The clinical syndromes consisted of amyotrophic lateral sclerosis in 2 patients, lower motor neuron syndrome with preserved reflexes in at least one limb in 3 patients, and motor neuropathy with multifocal conduction block in 1 patient. The presence of gammopathy appears to correlate with the absence of marked upper motor neuron involvement and with elevated CSF protein concentration. An underlying malignant disorder was ruled out in all 6 patients, and they were considered to have MG of undetermined significance (MGUS). In a control group of 121 age-matched patients with other neuroimmunological disorders, 5 patients (4.13%) had MG. Four of these had gammopathy associated with malignant myeloma, and 1 had MGUS. These results support previous reports of increased prevalence of MGUS in patients with MND and suggest that an autoimmune mechanism may play a role in the disease.

Adolescent↗
PubMed1991

Serum and CSF immunological findings in ALS.

Serum and CSF immunological findings were analysed in 37 patients with amyotrophic lateral sclerosis (ALS). ALS patients had significantly higher mean values of serum IgG and complement component C4 and significantly lower mean value of total haemolytic titre of complement (THC) compared with normal controls. Incidence of immune complexes (ICs) was significantly higher in sera of ALS patients than in normal controls. There was no significant difference regarding mean serum levels of IgM, IgA, and complement components C3 and Factor B between patients and controls. The blood-brain barrier (BBB) damage was found in 46% of patients. Intrathecal IgG synthesis was detected in six patients (16%). These results support the hypothesis of immune system involvement in ALS.

Adult↗
PubMed1990

Circulating autoantibodies in multiple sclerosis.

By using indirect immunofluorescence method, we analyzed the presence of antinuclear, anticardiac, microsomal, parietal-cell, smooth-muscle and mitochondrial antibodies in sera of 33 patients with definite multiple sclerosis (MS), without clinical evidence of associated autoimmune disorder, and 14 patients with other neurological disorders (OND). In MS patients, the prevalence of both organ-specific and non-organ-specific antibodies was significantly higher (p less than 0.05) than in OND patients. In both groups, the titers of circulating antibodies were low. The presence of low levels of autoantibodies in sera of MS patients might be the result of immunodysregulation in MS.

Adult↗
PubMed1983

The effect of l-DOPA and benserazide on the amount of dopamine in the corpus striatum of X-irradiated rats.

The effect of a mixture of l-DOPA and benserazide on the amount of dopamine in the corpus striatum of rats irradiated with 850 R of X-rays was investigated. The amount of dopamine in the corpus striatum was measured fluorimetrically at various times after irradiation. It was found that i.p. administration of l-DOPA and benserazide 1,2 and 5 days after irradiation produces significant replenishment of dopamine in the striatum, thus indicating that precursor uptake and metabolism, and probably amine storage, remained unaltered after irradiation.

Animals↗