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Biomedical subjects

S Popović

Publications and source records attributed to S Popović.

At least 19 recordsLinked to original sources
PubMed1996

Radioiodine uptake in thyroid cancer patients after diagnostic application of low-dose 131I.

The aim of this study was to investigate the influence of the diagnostic administration of 74 MBq 131I on subsequent uptake of therapeutic radioiodine in thyroid cancer patients. Retention measurements were performed using a whole-body counter in 24 patients 6 weeks after total thyroidectomy. Profile scans were performed 2, 24, 48 and 72 h after the administration of the diagnostic dose and 72 h after the administration of the ablation-therapeutic dose (4.4 GBq). The mean ( +/- S.D.) effective half-life of the diagnostic dose in thyroid remnants was 40.3 +/- 23.0 h. The uptake in the thyroid remnants of the subsequent ablation dose 72 h after administration was 30.4 +/- 19.8% of that predicted from the diagnostic study. The greater reduction in uptake was associated with the longer half-life of iodine and higher uptake in the thyroid remnants at 24 h, with a longer interval between surgery and administration of the diagnostic dose and a shorter period between administration of the diagnostic and ablation doses. Our results show that a diagnostic dose of 74 MBq 131I markedly reduces thyroid uptake of an ablation dose of 131I. This should be taken into account during radiation dose planning whenever a quantitative dosimetric study is to be performed.

Female↗
PubMed1996

[The ANLL-NS 02 protocol for individualized therapy in acute nonlymphoblastic leukemia].

ANLL-NS-02 program is intended for individualized therapy of patients with acute non-lymphoblastic leukemia. The program itself is based on a net of prognostic models providing prompt prognosis of bad outcome of the disease as well as their prevention or early treatment. Specific prevention of early death is conducted prior to and during the induction therapy. Prevention of resistance to cytostatic drugs is based on evaluation of the early effect of the first induction chemotherapy with three cytologic-mathematical parameters. Remission consolidation consists of two individualized courses. Older patients undergo maintenance therapy which differs in clonal and nonclonal remissions. Optimal time to perform bone marrow transplantation is determined by mathematical models based on clinical data. In patients with high risk of leukemic relapse, transplantation is performed in the first remission, while in others it is performed in eventual relapse. Parts of ANLL-NS-02 program are computerized and adapted for clinical utilization. This program has been used at our institution for 5 years and results have confirmed advantages of individualized therapy over standard protocols in treating acute non-lymphoblastic leukemia.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Effect of neurotoxin DSP4 on EEG power spectra in the rat acute model of epilepsy.

The effect of the adrenergic neurotoxin N-(chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4) on electroencephalographic (EEG) activity was studied in the model of epilepsy induced by systemic application of penicillin (1,000,000 IU/kg, i.p). DSP4 (50 mg/kg, i.p.) was administrated to male Wistar rats, while the control animals were rats from the same litters. EEG activity was recorded in acute and chronic experiments 3 or 4 weeks after DSP4 treatment, before and after penicillin administration. Occasional locus coeruleus (LC) stimulation served as an electrophysiological test of DSP4 toxic effect. EEG power spectra in DSP4 treated animals showed a tendency to be greater in lower frequency bands than in controls before penicillin administration; there was almost no effect of electrical LC stimulation, regardless on penicillin treatment. In the model of epilepsy, the mean total EEG power spectra were greater in the period of 135-330 min after penicillin administration, as well as during 345-540 min, in DSP4 treated animals as compared to the controls. It seems that neurotoxin DSP4 is an optimal tool for studying the removal of LC influence in the acute model of epilepsy. It is also suggested that norepinephrine (NE) may have a modulatory role in the systemic penicillin epilepsy.

Adrenergic Agents↗
PubMed1995

Gated versus first-pass radioangiography in the evaluation of left-to-right shunts.

Excluding regurgitant ventricles and multiple shunting, left-to-right shunts of the central circulation can be evaluated from the difference between the right ventricular stroke counts (SCRV) and the left ventricular stroke counts (SCLV), which are obtained from gated radioangiography. The pulmonary-to-systemic flow ratio (QP/Qs) is equated to SCRV/SCLV in atrial shunts and to SCLV/SCRV in ventricular and ductal shunts. In this paper, the potentials of the stroke count method have been compared to the gamma fit first-pass technique, incorporating the recent refinements in ductal shunts and deconvolution of the pulmonary curve. In 17 patients with left-to-right shunt, the stroke count method and the gamma fit method correlated moderately with oximetry (r = .71 and .87), respectively. The gamma variate method appeared superior in the detection and estimation of small shunts, whereas when QP/Qs was two or larger, the stroke count method yielded closer agreement with oximetry data.

Adolescent↗
PubMed1995

Interference of the sulphonylurea antidiabeticum gliquidone with mitochondrial bioenergetics in the rat under in vitro conditions.

The hypoglycaemic sulphonylurea gliquidone and glibenclamide exerted a partial uncoupling effect on mitochondrial respiration of liver under in vitro conditions using various citrate cycle intermediates as substrates. Besides the uncoupling effect, gliquidone and glibenclamide caused a direct inhibition of ATP-as well as DNP-stimulated oxygen consumption. Both phenomena proved to be dose dependent. Respiratory control ratio decreased progressively with increasing concentrations of sulphonylureas mainly through the inhibition of ADP-stimulated respiration. Basal and DNP-stimulated ATP-ase activity of isolated mitochondria changed similarly to the respiratory parameters. Changes in membrane permeability of mitochondria and the inhibition of substrate uptake further support the assumption of structural and functional alteration of mitochondria by the hypoglycaemic compounds tested.

Animals↗
PubMed1995

Interference of sulphonylurea antidiabetica with mitochondrial bioenergetics under in vivo conditions.

Sulphonylurea antidiabetica effectively inhibits the basal hepatic glucose production. Since it has been firmly established that lipophylic sulphonylurea drugs exerted an uncoupling effect on mitochondrial oxidative phosphorylation, a relationship between the reduction of hepatic gluconeogenesis and the insufficient energy supply due to sulphonylureas could be supposed. In this study we have investigated the effects of glibenclamide and gliquidone on mitochondrial bioenergetics in liver after peroral treatments of normal rats with different doses. The treatment of rats with 5 mg/kg glibenclamide or gliquidone daily for 14 days elicited only a marginal inhibition on mitochondrial oxidation capacity and remained without any effect on mitochondrial ATPase activity. Only the supermaximal dose 50 mg/kg for 14 day produced a significant damage in the mitochondrial functions. The basal respiration increased with 60-80 per cent, whereas the ADP- or DNP-stimulated oxygen consumption significantly decreased independently from the respiratory substrates investigated. Similar alterations were found in the mitochondrial ATPase activity after treatment with these drugs. No essential differences have been observed in the actions between glibenclamide and gliquidone. However, the lowest dose applied in this study is many times higher than the usual therapeutic dose. Consequently, glibenclamide and gliquidone do not interact with mitochondrial bioenergetic processes under therapeutic conditions. On the other hand, in different liver and kidney damages we have no sufficient knowledge whether these drugs can be accumulated in these organs and therefore their elevated concentration may interfere with the mitochondrial energy metabolism.

Animals↗
PubMed1994

Deconvolving out indicator smearing in the right ventricle facilitates left-to-right shunt quantitation.

A simple algorithm is developed to enhance the resolution of components of multimodal pulmonary radiohistograms. Based on the assessed right ventricular ejection fraction (RVEF), it deconvolves out the effect of indicator smearing in the right ventricle on the heart rate samples of the pulmonary radiohistogram, ck. The output is the ideal curve, c'k = ck/RVEF--(1-RVEF).ck-1/RVEF, that would be obtained if RVEF equalled unity. Since the formula is not a recursive one, it does not suffer from error propagation pertinent to numerical deconvolution. Once RVEF is known, implementation of the algorithm is simple. If RVEF is not known accurately it may be replaced with its upper estimate, RVEFup > RVEF, yielding a partial deconvolution of the curve. When applied to studies of patients with left-to-right shunt the method improves the accuracy and lessens the interobserver variation of the Maltz-Treves method.

Adult↗
PubMed1994

Model for radionuclide evaluation of left-to-right ductal shunts.

A model for radionuclide evaluation of left-to-right ductal shunts was designed. It was a generalization of the standard Maltz-Treves method, accounting for the possibility that distribution of the shunt flow between the two lungs differs from that in the right ventricular (RV) output (Fs). This yields a new formulation in which the ratio of ductal flow to pulmonary flow (Fd/Fp) equals a weighted average of Fd/Fp obtained separately for the right lung (RL) and the left lung (LL), i.e. Fd/Fp = R(Fd/FpP)RL+ (1-R) (Fd/Fp)LL; where R is the fraction of the RV output going to the right lung. Separate shunt-flow ratios can be obtained by conventional analysis of the respective lung radiohistogram, while R can be determined from the upslopes of these curves. Formulas were derived rigorously from basic principles, so that the ultimate clinical validity of the method depends on radioangiographic assessment of R, (Fd/Fp)RL and (Fd/Fp)LL. Due to asymmetry of flows there is no true referent method for patients with ductal shunts. Therefore a simulation study, using quasi-real data, was utilized, yielding satisfactory performances of the algorithm: (Fp/Fs) calculated = 0.92 (Fp/Fs)stimulated +0.15 (r = 0.878).

Algorithms↗
PubMed1994

[Human fetal pancreatic islet transplantation in insulin-dependent diabetics: possibilities of early detection of transplant destruction].

The factors determining the outcome of human fetal islet transplantation in patients with insulin-dependent diabetes mellitus (IDDM) remain unclarified. In this study we analysed the ratio between immunoregulatory lymphocyte subpopulations in order to search for a possible marker of the immune destruction of transplanted islets. Human fetal islets were isolated by collagenase digestion, cultured for 14 days at 37 degrees C, 5% CO2, and implanted under fascia of m. rectus abdominis in 7 IDDM patients (5 pancreata per patient). After transplantation we evaluated simultaneously the level of metabolic control through HbA1c values determined by chromatography, the capacity of insulin secretion through the C-peptide levels (determined by radioimmunoassay) before and 6 minutes after 1 mg glucagon i.v. stimulation, and the ratio between CD4+ and CD8+ lymphocytes determined by immunofluorescence using monoclonal antibodies. We found that metabolic control after transplantation was improved together with the decrease of the insulin daily dose, and the improvement was simultaneous to the increase of both basal and glucagon-stimulated C-peptide levels. Four months after transplantation we detected a remarkable decrease in the secretion capacity, accompanied by the necessity for an increase in daily insulin dose to maintain optimal metabolic control. However, the loss of islet function was preceded by the increase in CD4+/CD8+ ratio, thus reflecting the presumable accumulation of CD4+ inducer T-lymphocytes. When the islet secretion capacity was destroyed, we found a decrease in CD4+/CD8+ ratio, reflecting the recruitment of CD8+ effector cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Prognosis in patients with myelodysplastic syndromes based on cytomorphologic and clinico-biologic parameters].

Under myelodysplastic syndromes we presume a heterogeneous group of malignant hemopathies with clearly described characteristics of the disease given by a cooperative group of French, American and British authors. Myelodysplastic syndromes most frequently occur at older age. Survival of these patients, after the diagnosis is made, is mostly short because the disease evolves into acute leukemia. Myelodysplastic syndrome is characterized by appearance of refractive anemia, leukemia, thrombocytopenia with signs of expressed dishematopoiesis of the bone marrow. Clear criteria which could define forms with fast or slow course leading to acute leukemia don't exist, so there is a need to group patients into those with good or with bad outcome. The investigation included following parameters important for the outlook of the disease: 1. enlargement of lymph nodes, liver and spleen, 2. biochemical examination of peripheral blood, 3. cytomorphologic changes in the peripheral blood cells and bone marrow. By a follow-up of described parameters a statistically significant influence on survival of the sick concerning the degree of present anemia, absolute number of granulocytes, number of thrombocytes, dishematopoiesis of the peripheral blood and bone marrow, lymphadenomegaly, hepatomegaly and splenomegaly was not found. The percentage of blast in the peripheral blood and bone marrow has a statistically significant influence on patients' short survival.

Adult↗
PubMed1994

Non-stationary theory of blood-borne tracers.

Although cardiac mechanical activity causes periodic fluctuations of the regional volumes and flows through the cardiac chambers and great vessels, hitherto, the developed theory of blood-borne tracers has rested upon stationarity of flow, volume and distribution of transit time. Allowing for an arbitrary indicator injection, a more general theory is presented that accounts for periodic changes in the transport laws, flows and volumes of the system. When indicator particles are not thoroughly mixed with the entering blood, the intracycle changes violate most of the stationary equations. However, assuming complete mixing of indicator at the system inlet, in concentrations that do not change during the single cycle, this enables generalized counterparts of some of the most important stationary relations to be established. The difference between the indicator mean transit time calculated from the stationary assumptions and the one which allows for periodic kinetics is illustrated in radioangiographic assessment of the left ventricular ejection fraction.

Blood Volume↗
PubMed1994

Detection of diffuse skeletal lesions by monitoring the kinetics of labeled phosphonate.

A method of detecting of diffuse skeletal involvement in patients with metastatic tumors or with metabolic diseases is presented. The study consisted of 31 patients without bone disease and of 26 selected patients with diffuse skeletal involvement. The kinetics of 99mTc-dicarboxypropane diphosphonate (DPD) were calculated by monitoring the plasma and urine concentrations up to 5 hours after administration. Using these data, the renal clearance as well as the increase in urinary excretion of 99mTc-DPD were determined. The results indicate that measurement of the quantity of 99mTc-DPD excreted in the urine after 3 hours allows a reliable separation of the patients with diffuse skeletal lesions from normals. Other calculations such as renal clearance as well as the drop in plasma concentration were less sensitive. The test may be performed simultaneously with bone scintigraphy without additional radiation burden to the patient.

Adult↗
PubMed1992

[Smoking--II. Duration of smoking and factors affecting smoking as a social phenomenon].

According to the poll of 5,555 individuals (91% of the expected number) over 40 years of age, selected from electoral registers in all three districts of the community of Mali Idjos in 1987, the average duration of smoking among active smokers increases with age, divergently with regard to sex. The age of smokers at the time they started smoking increases with age groups, from 22.2 to 33.2 in males and from 28.1 to 49 in females. The onset of smoking in the oldest male group in this rural area occurred in the first years after the war (first land confiscation) while in the group from 70 to 74 years of age it occurred in the years of compulsory crop-purchase system. Agglomeration in the onset of smoking in two male age groups (60-64, 65-69) occurred at the time of the second land confiscation. The onset of smoking among females from all age groups, from 45 years on occurred in the first decade of the sexual revolution (1961-1971). The prevalence of smoking in the studied population was different in previous decades as well. It changes according to social factors: from political and economic changes among males to the changes in women's social status among females.

Adult↗
PubMed1992

[Prophylaxis and therapy of infections in allogenic bone marrow transplantation in patients with hematologic diseases].

Infection and acute graft versus host disease (GVHD) are the most common complications of allogeneic bone marrow transplantation, which compromise this therapeutical method for hematologic diseases. Beside the appreciation of customary preventive measures and the treatment of infections, it is necessary for every bone marrow transplantation center to analyze the development of bacterial, fungal and viral infections in the patients and to generate the most efficient and most rational program for their prevention and treatment. At the Hematology Department in Novi Sad seven allogenic bone marrow transplantations were performed in patients with malignant hematologic diseases and severe form of aplastic anemia. Prevention of the infection by isolation of the patient in a sterile unit, selective decontamination of the digestive tract with sterile food, skin and mucus hygiene and prophylactic drug administration proved rather beneficial and adequate for patients with the graft accepted, hematopoiesis recovered and immunity reconstructed. Risks of infections were increased by permanent vein catheter, acute GVHD and rejection of the bone marrow graft. Prompt isolation and identification of bacteria and fungi, especially in blood, the establishment of a minimal suppressing and bactericide antibiotic concentration, along with the assessment of their synergism, as well as early diagnosis of cytomegalovirus and administration of specific drugs, can significantly contribute to the more successful treatment of infections in transplanted patients.

Adolescent↗
PubMed1992

[Smoking--I. Smoking habits, number of cigarettes smoked].

A multiphase, oncologic, population screening was carried out in 5.555 residents (91% of the expected number) over 40 years of age, from three districts of the community of Mali Idos. The poll showed that 83.1% of males and 21.9% of females are familiar with smoking (ex-smokers or active smokers); 45.7% of males and 11.6% of females are active and 37.4% of males and 10.3% of females are exsmokers; 314 residents--11% of males and 1.3% of females smoke more than one pack of cigarettes daily; some of them smoke more than 60, 80, even 100 cigarettes daily. In two age groups (40-44, 45-49) 100% of male respondents is familiar with smoking; in the group over 75 years of age this percent is reduced to one third (21.8%). We can conclude that the distribution of smoking in this population differed in the middle and in the second half of the century.

Adult↗
PubMed1992

[Effect of polychemotherapy in the treatment of patients with non-Hodgkin's lymphoma].

Non-Hodgkin lymphomas belong to malignant hemopathies where clinical course, histological manifestation and therapy response are characterized by diverse features. Sensitivity of the lymphoma to chemotherapy introduced drug combinations for the improvement of patient survival rate and the prognosis. The study reviews the results achieved in 85 patients with NHL treated with different cytostatic combinations (COP, CHOP, COP-BLAM, MEV, LRS-074/B). The majority of the patients (41%) had entered the IV clinical stadium (Ann Arbor) with serious histological types of the disease (LDLL-45% and histiocytic 27%). This made us decide on LRS-074/B protocol (34%) and COP-BLAM cure (20%) planned for those with the advanced clinical stage and poor histological type of the disease. The full remission was achieved in 50%, partial in 28% of the cases while in 20% of the treated patients the therapy response lacked. Relapse of the disease occurs in about 50% of the treated patients. Patients treated with LRS-074/B protocol (p < 0.05) live statistically significantly longer. In a period of 24 months 50% of those treated with LRS-074/B protocol, COP and COP-BLAM cures show no symptoms. There is no a statistically significant difference regarding the mean survival rate (p > 0.05) in relation to the histological type of the disease.

Adult↗