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Biomedical subjects

A Popović

Publications and source records attributed to A Popović.

At least 19 recordsLinked to original sources
PubMed1999

Reversed-phase ion-pair HPLC determination of some water-soluble vitamins in pharmaceuticals.

A reversed-phase ion-pair high-performance liquid chromatografic method (RP-IPC) was developed to assay some water-soluble vitamins in solution dosage forms. Vitamins of the B-group B1, B2, B3, and B6, including vitamin C were determined in Oligovit coated tablets. In Beviplex coated tablets the vitamins B1, B2, B3, B6 and p-aminobenzoic acid were analysed. Hexanesulphonic acid sodium salt and triethanolamine in water methanol were used as mobile phase with adjusting pH to 2.8 with orthophosphoric acid. Phenol was used as an internal standard. For quantitative simultaneous analysis of vitamins in pharmaceutical formulations, the method of internal standard was used. All parameters for the validation of the method are given.

Ascorbic Acid↗
PubMed1996

Serial assessment of left ventricular chamber stiffness after acute myocardial infarction.

Left ventricular (LV) systolic function after acute myocardial infarction (AMI) has been the subject of detailed studies during the last decade, but diastolic phenomena during and after AMI are less well understood. Recently, it has been shown that early filling deceleration time accurately predicted LV chamber stiffness in an experimental model. To assess changes of LV stiffness after AMI, we studied 116 consecutive patients with 2-dimensional and Doppler echocardiographic examinations 1, 2, 3, 7, 21, and 42 days after AMI. Coronary angiography was performed in 101 patients. For the entire study group, deceleration time decreased nonsignificantly on day 2 and subsequently increased on days 3 (p = 0.001) and 7 (p = 0.036), returning toward initial values afterward. Deceleration time was shorter in large (peak creatine kinase level >1,000 U/L) versus small infarcts (p = 0.0008) and in patients with anterior versus inferior AMI (p = 0.02); there was no difference between patients with good and poor (< or = 45%) ejection fraction. These data indicate that increased LV stiffness can be detected 24 to 48 hours after AMI, but returns to normal within several days. Chamber stiffness is higher in large and anterior infarcts, but appears to be independent of LV systolic function.

Aged↗
PubMed1996

Altered gonadal hormone level and constant light-induced stress interfere with the response of the adrenal medulla to oxytocin.

The effect of oxytocin (0.25 IU/100 g per day) on the adrenal medulla was examined in intact, intact estrogen-treated, castrated and castrated testosterone-treated adult male Wistar rats. Stereological analysis of the gland (N = 5 rats per group) revealed that in intact animals the number of chromaffin cells (x10(3)) was significantly increased after 3-day (saline: 467.6 +/- 27.4; oxytocin: 567.6 +/- 28.9) or 7-day (saline: 486.2 +/- 39.1; oxytocin: 618.7 +/- 36.8) oxytocin administration. During 7 days of recovery after the 7-day treatment, the chromaffin cell number returned to the control level (saline: 491.4 +/- 12.6; oxytocin: 554.4 +/- 28.7). The effect of oxytocin on chromaffin cell number was also observed in rats simultaneously injected with estradiol (0.3 micrograms/100 g per day) for 10 days (estradiol: 454.3 +/- 32.8; estradiol+oxytocin: 576.1 +/- 25.0), as well as in 10-day castrated rats (saline: 594.7 +/- 22.7; oxytocin: 765.3 +/- 33.1). Testosterone replacement (0.6 mg/100 g per day) abolished the medullary response to oxytocin (testosterone+saline: 528.5 +/- 24.7; testosterone+oxytocin: 620.8 +/- 56.0). There was a 20% rise in adrenal dopamine content (from 0.236 +/- 0.015 to 0.283 +/- 0.015 microgram per pair of glands; N = 9-12) in intact rats injected with oxytocin for 3 days. Oxytocin had no effect on any of the catecholamine levels in adrenal glands of rats exposed to stress induced by constant lighting. The present data indicate that the proliferative response of chromaffin tissue to oxytocin depends on the gonadal hormone level and the basal activity of the adrenal medulla.

Adrenal Medulla↗
PubMed1992

Mitotic activity and cell deletion in ventral prostate epithelium of intact and castrated oxytocin-treated rats.

Previous study has shown that oxytocin (OT) attenuated the postcastration regression of ventral prostate epithelium in rats. To decide if this effect is associated with stimulation of cell division or improvement of cell survival, metaphase index of secretory cells and frequency of apoptotic bodies in the epithelium, combined with stereological parameters, were determined in the present study. OT was injected subcutaneously in a dose of 0.25 IU/100 g/d during 5 postorchiectomal days and the same treatment was applied to intact rats. Only the prostate of castrated animals responded to OT. They had greater total volume of the epithelium, total number and metaphase index of secretory cells, but lower frequency of apoptotic bodies. These findings demonstrate the ability of OT to stimulate mitotic activity and to diminish mortality of secretory cells caused by orchiectomy.

Animals↗
PubMed1992

[The effect of occupational noxae in the tobacco industry on pulmonary function in exposed workers].

A study was carried out to determine respiratory hazards to workers in tobacco manufacture. The investigations at the workplace included analysis of the work technology and measurements of chemical pollutants and dust concentrations in the work rooms. Ventilatory lung function tests were performed in 95 workers exposed to tobacco dust and in 129 control workers. Results of workplace analysis showed the presence of tobacco dust levels exceeding the maximum permissible concentrations. The values of some lung function tests for exposed workers non-smokers were significantly lower than for control workers non-smokers. They could be attributed to the effect of occupational noxae on the respiratory system.

Adult↗
PubMed1990

The response of rat adrenal zona fasciculata and zona reticularis to oxytocin treatment.

The response of the adrenal zona fasciculata (ZF) and zona reticularis (ZR) to oxytocin (OT) was examined in male rats using a stereological method. The 10-day administration of 0.25 IU OT/100 g daily caused an enlargement of ZF due to cell hypertrophy associated with striking lipid accumulation. The volume of ZR was decreased, this change being the consequence of the reduced cell population. The possible site of OT action is discussed.

Adrenal Glands↗
PubMed1990

Stereologic analysis of ventral prostate of oxytocin-treated rats.

Ventral prostate response to oxytocin (OT) was examined in intact and castrated adult rats. The treatment consisted of 10 daily subcutaneous injections of 0.25 IU OT per 100 g body weight, which for orchiectomized rats began immediately after surgery. OT induced prostatic response only in castrated animals. Stereologic analysis revealed changes in the epithelial component, its total volume and surface being increased. The acinar lumen as well as the glandular weight were also enhanced. A possibility that the ventral prostate is the target organ for OT is discussed.

Animals↗
PubMed1989

The response of rat adrenal medulla to oxytocin.

Effects of oxytocin (OT) on the adrenal chromaffin tissue of male rats were examined by coupled morphometric and biochemical techniques. Synthetic OT was administered in doses of 0.14 and 0.25 IU/100 g/d during 7 or 10 consecutive days and the effects were followed 1, 24, 72 and 168 hours after the last injection. The function and structure of chromaffin cells were affected by the higher dose of OT only. They caused divergent responses on their amine contents. Adrenaline, noradrenaline and dopamine contents were increased, while serotonin content was decreased. These changes were different in duration and time of incidence. Stereological analysis showed an enhanced number of chromaffin cells and an increase in their total volume. The parallelism between the changes in chromaffin cell number and the catecholamine content strongly suggests a mitogenic effect of the applied OT.

Adrenal Glands↗
PubMedDate not supplied

Rat accessory sex glands response to oxytocin under different light regimens.

Effects of oxytocin (0.25 IU OT/100 g/d for 3 days) on accessory sex glands structure and catecholamine content were examined in rats kept on two different light regimens. In 12 h light/12 h dark conditions ventral prostate responded to OT by a regression of the epithelial component and an increase in dopamine content. Coagulating gland structure was not affected, but noradrenaline content of the seminal vesicle+coagulating gland complex was enhanced. Constant lighting per se caused atrophic changes in the prostatic epithelium, evident by decreased total volume and by increased percentage of acini containing cuboidal epithelium. OT treatment considerably prevented the epithelial atrophy without affecting catecholamines level. In the seminal vesicle+coagulating gland complex it reduced the dopamine content. Since this light regimen elevated the plasma ACTH, the altered accessory sex gland response to OT seems to be due to the stress-induced changes in the neuro-endocrine factors conditioning their function. The effects of OT on accessory glands catecholamine content indicate interferences with their autonomic control.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[Reversible left ventricular dysfunction in coronary disease (part one): myocardial stunning].

INTRODUCTION: The concept of myocardial stunning has been proposed by Braunwald and Kloner in early 1980's and is defined as transient postischemic myocardial dysfunction that persists after reperfusion, despite the absence of irreversible damage and restoration of normal or near normal coronary flow. Thus, the hallmark of stunned myocardium is the mismatch between coronary flow and myocardial function. MYOCARDIAL STUNNING: The two most plausible hypotheses used to explain the pathogenetic mechanisms of myocardial stunning are calcium and oxyradical hypotheses. According to the first one, myocardial stunning is the result of impaired calcium homeostasis caused either by calcium overload or decreased responsiveness of myofilaments to calcium. The oxyradical hypothesis postulates that generation of free oxygen radicals depresses myocardial function after the ischemic episode. The exact mechanism is unknown, but it is probably due to extreme reactivity of oxyradicals that bind to some cellular components, impairing membrane permeability and function of various cell organelle. Stunned myocardium can be seen in numerous clinical situations in which myocardial ischemia has been followed by reperfusion. These include: coronary artery bypass surgery, acute myocardial infarction, stable, unstable and variant angina, percutaneous transluminal coronary angioplasty and cardiac transplantation. DISCUSSION AND CONCLUSION: In majority of these situations, stunned myocardium is usually well tolerated. However, there is a group of high-risk patients in whom prolonged myocardial dysfunction due to stunning can cause serious hemodynamic instability, which requires pharmacological and/or mechanical support. Therefore, in order to avoid these situations, some authors have suggested that stunned myocardium should be prevented, rather than treated. Since stunned myocardium is by definition reperfused, with normal or near normal coronary flow, treatment is reserved only for those patients in whom stunned region is large enough to cause low cardiac output and hypotension. Revascularisation is usually unnecessary; however, there are situations in which episodes of repetitive stunning cause chronic myocardial dysfunction along with hibernated myocardium, when myocardial revascularization would be beneficial.

Animals↗