Aleksandar Milovanovic

Reactions with lead tetraacetate—IV : Oxidation of saturated aliphatic alcohols—II; Alcohols of low molecular weight

Abstract The action of lead tetraacetate on ethanol, 1-propanol, 2-propanol and 2-butanol has been studied under various experimental conditions, and it was found that the tetravalent lead compound reacts with alcohols in ways not so far observed. The possible reaction schemes are discussed in terms of homolytic and heterolytic cleavage of the intermediate alkoxy lead acetate complexes.

Burnout, quality of life and emotional profile in general practitioners and psychiatrists.

OBJECTIVE Many studies confirm that psychological factors and burnout in physicians are interconnected. It is however not known, whether quality of life is another factor that plays a role in this connection.The aim of this study was to explore the correlation between quality of life and emotional profile with the level of burnout in physicians. PARTICIPANTS 120 physicians participated in this study, i.e., sixty general practitioners (GPs) and sixty psychiatrists. METHODS The General Health Questionnaire (GHQ) and the Maslach Burnout Inventory (MBI) were used to measure the job stress. The Quality of Life (QOL) and the Emotions Profile Index (EPI) were used to determine quality of life and emotional profile. Data were analyzed using methods of single and multiple correlation and regression methods. RESULTS The QOL was higher in psychiatrists as a direct consequence of questions about finances and friendship. Analysis by gender showed that the growth of the burnout risk level (MBI) correlated with the growth of number of women who had stress coping problems. CONCLUSIONS This research suggests that quality of life and individual factors represent a very significant role in burnout among physicians. Further researches in a bigger sample are required in order to identify key factors of quality of life related to burnout reducing, as well as for improvement of supervision strategies, including more the relevance of psychological profile of physicians.

New Types of Steroidal Isoxazolidines

Synthese de 1β,5- et 3β,5- epoxyimino steroides a partir de N-methyl hydroxylamine et de 5,10-secosteroides

Oxidative β -fragmentation of 19-nor-5α-androstane-3β, 5, 17β-triol 3, 17-diacetate

Abstract The preparation of 19-nor-5α-androstane 3β,5, 17β-triol 3,17 diacetate (10) is described. When this alcohol was treated with the mercuric oxide-iodine reagent it underwent fragmentation of the C(5)–C(10) bond with formation of a new type of 10-membered ring containing 5,10-seco-steroidal compounds, i.e. (Z)-and (E)-19-nor- 3β, 17β diacetoxy-5,10-seco-androst-1(10)-en-5-one (11 and 12), in 27 and 49% yield, respectively.

Inter-individual variability in the response of human peripheral blood lymphocytes to ionizing radiation: comparison of the dicentric and micronucleus assays

Ionizing radiation can induce a wide range of DNA damage that leads to chromosomal aberrations. Some of those aberrations (dicentrics and micronuclei) are applied in biodosimetry. Biological dosimetry assumes similar radiosensitivity of each donor, but it does not exclude inter-individual variations in radiation susceptibility. Therefore, for biological reasons, it is always challenging to investigate inter-individual variability in response to radiation. For mechanistic reasons, it is also interesting to investigate the correlation between dicentric and micronuclei formation in response to radiation. In this experiment, irradiated blood specimens from 14 healthy male and female donors have been used to evaluate inter-individual variability in response to the genotoxic effects of X-ray radiation, as well as the dose–response relationship and test sensitivity using two endpoints (dicentrics and micronuclei). The results showed similar patterns of cytogenetic biomarker distribution between donors, but differences in the response of some donors at some doses. Data also showed that responses of male donors were better detected using the dicentric test, while for females, micronucleus frequencies were higher in response to the same dose of radiation. No influence of smoking status or age on specific responses was observed. Group variability in response to radiation was evaluated using coefficient of variation for each group of individuals irradiated with the same doses; as the dose increases, group variability becomes substantially lower. Despite sporadic inter-individual variability, trend of radiation-induced changes was similar. Produced calibration curves for both types of damage revealed dicentrics as genetic damage more typical for radiation than micronuclei.

Structure-reactivity relationship in 19-methyl-and 19-nor-5,10-secosteroids. Part 4. Intramolecular nitrone 1,3-dipolar cycloadditions

The (Z)-19-nor-5,10-secosteroidal ketone 11 reacts with hydroxylamine hydrochloride to give the (E)- and (Z)-oximes 12 and 13, while with N-methylhydroxylamine hydrochloride it undergoes transannular nitrone 1,3-dipolar cycloaddition to give isoxazolidines 14 and 15, and an estratriene derivative 16, originating from 14. The (E)-19-nor-5,10-seco-ketone 17 undergoes intramolecular nitrone 1,3-dipolar cycloaddition with both hydroxylamine hydrochloride and N-methylhydroxylamine hydrochloride to produce, with the former reagent, a single isoxazolidine 18, and with the latter, two regioisomers 22 and 23. The reaction and stereochemical courses of the above transformations are compared with those previously observed for the corresponding 19-methyl analogues. Copyright (C) 1996 Published by Elsevier Science Ltd.

Structure–reactivity relationships in normal and 19-nor-5,10-seco-steroidal cyclodecenone systems. Part 1. Acid-catalyzed and thermal reactions

Under acid-catalyzed conditions both the (Z)- and (E)-19-nor-seco ketones (1a) and (2a) underwent transannular cyclization [forming the C(5)–C(10) bond], accompanied by aromatization of the resulting ring A, to give estra-1,3,5(10)-trien-17β-yl acetate (4)(in 76% and 83% yield, respectively). On the other hand, when the corresponding 19-methyl analogues (1b) and (2b) were treated with acid under similar experimental conditions, the (Z)-diastereoisomer (1b) remained mostly unchanged, while the (E)-19-methyl-seco ketone (2b) afforded the A-nor-B-homo derivative (5)(in 68% yield). The same transannular cyclization of the (E)-seco ketone (2b) was also achieved thermally in the absence of protonation.

Vicinal phenyl group shift in the lead tetraacetate and related oxidations of 5,5,5-triphenyl-1-pentanol

Abstract In the lead tetraacetate and heavy metal-bromine oxidations of 5,5,5-triphenyl-1-pentanol 1d , the major cyclization product obtained was the rearranged 2,2,3-triphenyltetrahydro-2 H -pyran 11d , resulting from homolytic and heterolytic 1,2-phenyl group shift (the latter only in the lead tetraacetate reaction) in the respective intermediate species with electron deficient δ-carbon 4d and 6d .

Oncological and Functional Outcome after Surgical Treatment of Early Glottic Carcinoma without Anterior Commissure Involvement

Introduction. Glottic carcinoma can be successfully diagnosed in its early stages and treated with high percentage of success. Organ preservation and optimal functional outcomes could be achieved with wide array of surgical techniques for early glottic cancer, including endoscopic approaches or open laryngeal preserving procedures, making surgery the preferred method of treatment of early glottic carcinoma in the last few years. Material and Methods. Prospective study was done on 59 patients treated for Tis and T1a glottic carcinoma over a one-year time period in a tertiary medical center. Patients were treated with endoscopic laser cordectomy (types II–IV cordectomies according to European Laryngological Society classification of endoscopic cordectomies) and open cordectomy through laryngofissure. Follow-up period was 60 months. Clinical and oncological results were followed postoperatively. Voice quality after the treatment was assessed using multidimensional voice analysis 12 months after the treatment. Results. There were no significant differences between oncological and functional results among two groups of patients, though complications were more frequent in patients treated with open cordectomy. Conclusion. Endoscopic laser surgery should be the first treatment of choice in treatment of early glottic carcinomas, though open approach through laryngofissure should be available for selected cases where anatomical factors present limiting adequate tumor removal.

Low micromolar concentrations of cadmium and mercury ions activate peritubular membrane K+ conductance in proximal tubular cells of frog kidney.

The present study was designed to investigate the acute effects of extracellular low micromolar concentrations of cadmium and mercury ions on the peritubular cell membrane potential and its potassium selectivity in proximal tubular cells of the frog kidney. Peritubular exposure to 3 micromol/L Cd(2+) or 1 micromol/L Hg(2+) led to a rapid, sustained and reversible hyperpolarization of the peritubular cell membrane, paralleled by an increase in fractional K(+) conductance. Peritubular barium abolished hyperpolarization of the peritubular cell membrane to peritubular 3 micromol/L Cd(2+) or 1 micromol/L Hg(2+). Perfusing the lumen with 10 mmol/L l-alanine plus/minus 3 micromol/L Cd(2+) or Hg(2+) did not modify rapid depolarization and rate of slow repolarization of the peritubular cell membrane potential. In conclusion, low micromolar concentrations of Cd(2+) and Hg(2+) increase K(+) conductive pathway in the peritubular cell membrane and in this way can enhance ability of proximal renal tubular cells to maintain the driving force for electrogenic Na(+) and substrate reabsorption.