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Biomedical subjects

B Momcilović

Publications and source records attributed to B Momcilović.

At least 19 recordsLinked to original sources
PubMed2006

Ion release from gold/platinum dental alloy: could release of other elements be accountable in the contact allergy attributed to the gold?

OBJECTIVES: The release of metal ions (Al, Ag, Au, Ca, Cd, Co, Cr, Cu, Mg, Mo, Ni, Pd, Pt, Ti, and Zn) from the commercial gold/platinum (Au/Pt) dental alloy of declared composition was studied. METHODS: Au/Pt was soaked in pH 6.0 phosphate buffer, 3.5 pH phosphate buffer and pH 3.5 mixture of lactic, formic and acetic acid, and incubated at 37 degrees C for 1, 2, 3, 4, 5, 6, 7, 14, 21, and 30 days. Six samples (n = 6) of every solution were prepared for any time period. Inductively coupled plasma atomic emission spectroscopy was used for analysis of the released elements. RESULTS: Results demonstrated release of only Cr, Cu, Fe, and Zn from the tested Au/Pt dental alloy (ANOVA, p < 0.001 for buffer, time, and interaction, respectively); however, only Cu and Zn were declared. CONCLUSIONS: The undeclared chromium from Au/Pt dental alloy, or some other element might be responsible for the contact allergy thus far attributed to the gold.

Dental Alloys↗
PubMed1999

[Megamin, faith, hope and placebos---a critical review].

Megamin is a registered nutriceutical in Croatia. Allegedly, it consists mostly of a naturally occurring zeolite (aluminum silicate) ion-exchange material tagged with vitamins and minerals. Mass-media claimed that Megamin possessed strong anticancer properties although it had not been tested through an appropriate, randomized, double-blind, placebo-controlled, crossover clinical trial. The paper uses Megamin as a paradigmatic model to discuss how higher neurocognitive functions like hope and faith may be related to the placebo effect and give an illusion of symptomatic well being without supporting evidence in the objective signs of the disease. The only plausible role of Megamin is that it reduces gastrointestinal toxic burden by affecting the anaerobic fermenting processes after digestion of food and by removing harmful metabolites after medical treatment of cancer and/or liver and kidney organ failure. The psychological effect of unwarranted mass-media claims about the beneficial role of Megamin in cancer treatment is scrutinized.

Antineoplastic Agents↗
PubMed1999

["More is not better"--evaluation of toxicologic risks of the heavy metals, lead and cadmium, and the herbicides, linuron, fluazifop-P-butyl and cycloxydim in dried Chamomile flowers (Chamomilla recutita L. Rauschert)].

Cadmium and all three enumerated herbicide residues in dried samples of industrially grown true chamomile were found to be above the suggested and accepted tolerance values. The results are discussed with regard to the current Croatian regulation and FAO/WHO recommendations on herbicides and to human toxicology risk assessment. The paper gives a critical evaluation of the herbicide overuse in agricultural practice and strongly discouraged such practice. The authors advocate prospective use of plants as natural indicators of environmental contamination and toxicological burden of the human food chain.

Cadmium↗
PubMed1999

A case report of acute human molybdenum toxicity from a dietary molybdenum supplement--a new member of the "Lucor metallicum" family.

The paper gives a brief review of human molybdenum metabolism and toxicity and presents the first known case of acute clinical poisoning with molybdenum from the dietary molybdenum (Mo) supplement in a male patient in late thirties. In over 18 days, the patient had consumed a cumulative dose of 13.5 mg Mo (300-800 micrograms Mo/day). Followed the development of acute psychosis with visual and auditory hallucinations, a series of petit mal seizures, and one life threatening grand mal attack. The symptoms remitted several hours after the start of chelation therapy with calcium ethylene diamine tetraacetic acid (CaEDTA). A battery of neuropsychological tests and Spectral Emission Computer Tomography demonstrated evident frontal cortical damage of the brain. One year after the Mo poisoning, the patient was diagnosed toxic encephalopathy with executive deficiencies, learning disability, major depression, and post-traumatic stress disorder. The paper strongly advocates issuance of and strict adherence to written warnings on the instruction labels not to mix potentially harmful neurotoxic substances, such as molybdenum, with other nutriceuticals and to instructions stating maximal single and cumulative doses. Molybdenum is a new and unwelcome member of the "metal madness" family.

Acute Disease↗
PubMed1999

Environmental radon daughters reveal pathognomonic changes in the brain proteins and lipids in patients with Alzheimer's disease and Parkinson's disease, and cigarette smokers.

This paper presents an investigation of the retention of environmental radon daughters, 210Po (alpha particle emitting radio-nuclide) and 210Bi (beta particle emitting radio-nuclide), in lipid and protein fractions of the cortical grey and subcortical white matter from the frontal and temporal brain lobes of patients who had suffered from Alzheimer's disease or Parkinson's disease, of cigarette smokers, and of control subjects. 210Po and 210Bi radioactivity increased tenfold in the cortical grey and subcortical white protein fraction in patients with Alzheimer's disease and smokers, and tenfold in the cortical grey and subcortical white lipid fraction in patients with Parkinson's disease. Free radicals generated by radon daughters may add to the severity of the radio-chemical injury to the brain astrocytes. The pathognomonic distribution of radon daughters to lipids in patients with Parkinson's disease and to proteins in patients with Alzheimer's disease was attributed to high chlorine affinity of radon daughters. The changes in the membrane protein pores, channels, and gates in patients with Alzheimer's disease and in the lipid bilayer in patients with Parkinson's disease are at the core of what the authors think are two systemic brain diseases.

Aged↗
PubMed1997

Idiorrhythmic dose-rate variability in dietary zinc intake generates a different response pattern of zinc metabolism than conventional dose-response feeding.

We compared the effects of idiorrhythmic dose-rate feeding and conventional dose-response on the induction of intestinal metallothionein (iMT), expression of aortal heat-shock protein mRNA (HSP70mRNA) induced by restraint stress, and accumulation of Zn in the femur and incisor of young growing male rats. An idiorrhythmic approach requires that the average dietary Zn concentration (modulo, M) over the whole experiment (epoch, E) is kept constant across different groups. This is done by adjusting the Zn concentration of the supplemented diet supplied to compensate for the reduction in the number of days on which Zn-supplemented diet is fed, the latter being spread evenly over the experiment. Idiorrhythms involve offering the diet with n times the overall Zn concentration (M) only every nth day with Zn-deficient diet offered on other days. Idiorrythmic Zn dose-rate feeding changed Zn accumulation in the femur and incisor in a complex bi-modal fashion, indicating that metabolic efficiency of dietary Zn is not constant but depends on Zn dose-rate. In contrast to feeding Zn in the conventional dose-response scheme, iMT and HSP70mRNA were not affected by idiorrhythmic dose-rate feeding. Idiorrhythmic cycling in dietary Zn load posed no risk of a biochemical overload nor caused the animals to be stressed. Idiorrhythmic dose-rate feeding brings the dimension of time to the conventional dose-response model.

Animal Nutritional Physiological Phenomena↗
PubMed1997

Contribution of lead poisoning to renal impairment.

The late effects of lead on kidney function and blood pressure were studied in 38 persons occupationally poisoned in the past and in 23 workers exposed to lead. Parameters evaluated in all subjects were: creatinine clearance, hippuran renal flow, blood lead, erythrocyte protoporphyrin, aminolevulinic acid dehydratase, and blood pressure. Out of 11 combined variables, four significant factors were identified by factor analysis. The results showed the presence of the delayed adverse effect of previous occupational lead poisoning on kidney function and blood pressure. This phenomenon is a complex interplay of lead poisoning in the past, overall duration of lead exposure, and age as a major confounding variable related to aging process of the kidneys.

Adult↗
PubMed1996

Chronic lead poisoning, renal function and immune response.

The aim of this study was to investigate possible correlations between chronic, recurrent lead poisoning, renal function and immune response. The study involved 74 patients with a history of at least one lead poisoning. Fifty-three patients were occupationally poisoned, and 21 were poisoned accidentally after consumption of alcohol beverages or food from lead glazed pottery. In all patients glomerular filtration rate (GFR) was determined by measuring creatinine and DTPA clearances, and T- and B-lymphocytes were assessed as indicators of cellular and humoral immunity. A significant negative correlation was found between the number of past lead poisonings indicating increased lead body burden, and both creatinine and DTPA clearances. There was a significant positive correlation between the number of poisonings and the percentage of B-lymphocytes (r = 0.31; P < 0.05), and no correlation at all with the T-lymphocyte count. Our results show that chronic, recurrent lead poisoning with a consequently increasing lead body burden can cause an impairment in renal function and a concomitant stimulation of humoral immunity.

Adult↗
PubMed1995

Coupling of zinc dose to frequency in a regularly recurrent pattern shows a limited capacity of excessive dietary zinc to compensate for a previously deficient intake.

The impact of feeding a proportional dose of zinc in a regularly recurrent pattern (idiorrhythmic feeding) on body growth of weanling rats was studied to assess the extent to which an intake exceeding the requirement could compensate for a previously deficient intake. The idiorrhythmic regimen (1) was designed so that the overall dose-time equivalent (modulo; Mx) was kept constant over a selected period of time (epoch; E), whereas the actual dose and frequency varied regularly according to a predetermined pattern; that is, I = dnth(Mx)/dnth, where Mx and dnth are the selected dose-time equivalent and the sequential number of zinc-dosing days, respectively. For example, 3 mg Zn.kg-1 diet fed every day (I = 3/1) and 24 mg Zn.kg-1 diet fed 1 d in an 8-d period (7 d of feeding a zinc-deficient diet) (I = 24/8) are dose-time equivalents because they both provide 72 mg Zn.kg-1 over a 24-d E. Modulos of M3, M6, M12 and M24 were used, which provided 3, 6, 12 and 24 mg Zn.kg-1.d-1 dose-time equivalents during a 24-d E. Each modulo had seven analogous idiorrhythms: I = Mx/1, 2Mx/2, 3Mx/3, 4Mx/4, 5Mx/5, 6Mx/6 and 8Mx/8; for example, with 8 Mx/8, 24, 48, 96 or 192 mg Zn.kg-1 diet was fed every 8th d; on the other 7 d a diet without a zinc supplement was fed for M3, M6, M12 and M24, respectively. Zinc dose-rate idiorrhythm generated a complex, gestalt-like, biphasic growth response pattern where an intake of dietary zinc exceeding requirements had either no effect (M3 or average of 3 mg kg-1 diet) or fully compensated for only 1 (M6 and M12 or average of 6 and 12 mg Zn.kg-1 diet) or 2 (M24 or average of 24 mg Zn.kg-1 diet) d.

Animals↗
PubMed1993

Delayed effects of lead on the kidney--factor analysis.

A late, i.e. delayed, effect of lead on kidney function and blood pressure was studied in 23 workers with a history of occupational lead poisoning. Twenty lead exposed workers with no known history of lead poisoning were a positive control. Four important factors out of 11 combined variables derived from 22 single variables were identified by factor analysis. The first factor comprised the variables kidney function, blood pressure, age, duration of lead exposure and the number of previous lead poisonings. The second factor comprised the variables duration of lead exposure and biological indicators of lead exposure. The third factor correlated the frequency of previous lead poisonings with the renal blood flow, erythrocytic protoporphyrin and age. The fourth factor comprised the variables length of work service, creatinine clearance and erythrocytic protoporphyrin. The results confirm the presence of the adverse late effect of previous occupational lead poisoning on kidney function regardless of treatment. The phenomenon is not a single event but a complex interplay of past lead poisoning, duration of exposure to lead, "normal" age effect on an increase in systolic and diastolic blood pressure and blood creatinine and a decrease in renal function as revealed by decreased creatinine clearance and a slow down in renal flow time. The complexity of dealing with the confounding variable of age and lack of appropriate classification of renal function impairment may account for the conflicting results of chronic lead effect upon kidney function in the past. The kidney appears to be a critical target organ, reflecting the total lead body burden in chronic lead exposure and poisoning. Therefore monitoring of kidney function in lead exposed workers needs to be mandatory.

Adult↗
PubMed1992

[Late changes in renal function after lead poisoning and chelation therapy].

Glomerular filtration rate was examined by determination of creatinine clearance in 22 adult males with a past history of lead poisoning. Eighteen subjects had been poisoned after many years of occupational exposure to lead and four had been poisoned by ingestion of alcohol beverage kept in lead-glazed pots. Seventeen subjects were treated with the chelating agent calcium-disodium-edetate (CaNa2EDTA), the remaining five received no treatment. The aim of the study was to examine the delayed effects of lead poisoning on kidney function and the possible difference in functional impairment between the treated and the non-treated subjects. The results obtained demonstrated a significantly reduced glomerular filtration rate, adjusted for age, in subjects poisoned by lead in the past who failed to receive specific treatment (P < 0.01). This indicates the possibility of marked, delayed adverse effect of lead on the kidneys in cases when lead body burden has not been reduced by treatment.

Adult↗
PubMed1982

Growth pattern and skeletal age in school girls with idiopathic scoliosis.

The growth patterns in girls ten to 16 years of age with idiopathic structural scoliosis are different from the growth patterns of normal girls of the same age group. Overall standing and sitting heights were 5 cm and 2 cm greater, respectively, in 207 scoliotic as compared with 210 randomly selected, age-matched healthy girls. Hand and wrist radiographs revealed an advanced skeletal age in scoliotic girls at ten years of age, whereas subsequent skeletal development was more rapid in healthy girls.

Adolescent↗
PubMed1979

Lead metabolism in lactation.

A 2-fold increase in lead absorption was observed in lactating animals which received 2 mg Pb/l in drinking water. About one-half of the absorbed lead was transferred to the litters.

Animals↗
PubMed1976

Bioavailability of zinc in milk and soy protein-based infant formulas.

Total femur zinc of young rats was used to evaluate the biological availability of zinc in milk and soy protein-based infant formulas. A zinc deficient diet (0.8 mug Zn/g) containing egg white protein was supplemented with graded levels of zinc from zinc sulfate, milk and soy protein-based infant formulas. A plot of total femur zinc (log) after feeding the diet for 3 weeks versus the zinc added to the diet gave a linear relationship over the range of 0, 3, 6, 9 and 12 mug/g added zinc. By using a slope-ratio bioassay model, the relative biological availability of endogenous and added zinc in milk-based formula was estimated to be 0.86 and that of soy-based formula 0.67 (zinc sulphate = 1.00) with corresponding 95% fiducial limits being 0.82 to 0.91 and 0.62 to 0.71. Thus, to provide equivalent amounts of available zinc, the total zinc content of the soy protein-based formula would need to be at least 20% higher than that of the formula containing milk protein.

Animals↗