CONCENTRATION OF POLYAMINES IN THE RAT LIVER DURING POSTNATAL PERIOD

Polyamines, spermine, spermidine, and putrescine are ubiquitous in living cells. Polyamines play important roles in cell growth, proliferation, and survival. Our aim was to determine the concentration of the spermine, spermidine, and putrescine in the rat liver during the first 6 months of postnatal life. A total of 45 albino Wistar rats, maintained under controlled temperature (20±2°C) in the animal room facilities were included in this study. On the day 1, 3.5 months, and 6 months of postnatal life, rats were sacrificed by cervical dislocation. Thr liver was removed and washed in the 0.9% solution of sodium chloride. Concentrations of spermine, spermidine, and putrescine were determined. Concentration of polyamines in the liver tissue of the Wistar albino rats aged 1 day, 3.5 months, and 6 months was respectively: spermine (Sp) (33.81 ± 3.04; 128.15 ± 6.62; 74.34 ± 1.12 mg/g of wet weight); spermidine (Spd) (121.92 ± 6.23; 53.34 ± 3.31; 56.32± 1.41 mg/g wet weight); and putrescine (Put) (8.92 ± 0.98; 9.37 ± 0.98; 20.93 ± 1.15 mg/g wet weight). Polyamine concentration in the rat liver fluctuated during postnatal life. The concentration of the spermidine was highest in the rat liver on the first postnatal day, much higher than spermine, this ratio inverted in 3.5 months old rats. The concentrations of the spermidine and spermine were almost equal at the 6 months of the postnatal life. The concentration of putrescine steadily increases during postnatal life

THE INFLUENCE OF VARIOUS MICROENVIRONMENTAL FACTORS ON BIOMECHANICAL FEATURES OF DIFFERENT SUTURE MATERIALS USED IN HEPATO-PANCREATO-BILIARY SURGERY

The key features of any suture material, such as its tensile strength, knot security, resorbability, handling characteristics and biological behavior must be taken into account during the selection process. These biomechanical features may be variable in different microenvironmental conditions in the human body in which the sutures are placed due to the influence of numerous local biohumoral factors. We have reviewed the data on the impact of pancreatic juice and bile, various pH conditions, chemotherapy and heat on different suture materials behavior. It is suggested that in pancreatic and biliary surgery polydioxanone sutures should be used. The review has also demonstrated that absorbable suture materials were more sensitive to pH than non-absorbable sutures. In addition, polyglyconate sutures were the strongest of all absorbable synthetic sutures when exposed to heat and cytotoxic drugs. This review provides a better basis for the selection of suture materials for specific applications

Gentamicin nephrotoxicity in animals: current knowledge and future perspectives

Due to high relative blood flow the kidney is prone to drug-induced damage. Aminoglycoside type antibiotic gentamicin is one of the leading cause of drug-induced nephrotoxicity. In recent years gentamicin nephrotoxicity is significantly reduced by shifting to once daily dosage as well as by eliminating known risk factors. Application of gentamicin is still related to serious side effects which are reported more often compared to other antibiotics. Because gentamicin is still heavily used and is highly efficient in treating infections, it is important to find mechanisms to reduce its nephrotoxicity. This aim can only be achieved through better understanding of kidney metabolism of gentamicin. This problem has been extensively researched in the last 20 years. The experimental results have provided evidence for almost complete understanding of mechanisms responsible for gentamicin nephrotoxicity. We now have well described morphological, biochemical and functional changes in kidney due to gentamicin application. During the years, this model has become so popular that now it is used as an experimental model for nephrotoxicity per se. This situation can mislead an ordinary reader of scientific literature that we know everything about it and there is nothing new to discover here. But quite opposite is true. The precise and complete mechanism of gentamicin nephrotoxicity is still point of speculation and an unfinished story. With emerge of new and versatile technics in biomedicine we have an opportunity to reexamine old beliefs and discover new facts. This review focuses on current knowledge in this area and gives some future perspectives

BIOCHEMICAL AND HISTOPATHOLOGICAL EFFECTS OF MOBILE PHONE EXPOSURE ON RAT HEPATOCYTES AND BRAIN

Microwave radiation MWR is widespread in human environment. The most frequent sources of MWR are mobile phones and cell towers. The effects of MWR are still unknown and there are insufficient data about long-term MWR effects on hepatocytes and brain structures.The aim of this paper was to investigate the biological effects of mobile phone microwave radiation on the brain and liver of experimental animals and to determine the increase in oxidative stress as a possible pathogenetic mechanism for harmful effects of long-term exposure.Wistar rats, 3 months old, were divided into two groups: I-rats constantly exposed to MWR (3 female and 2 male) and II-control animals without near source of electromagnetic field (EMF) (3 female and 2 male). The microwave radiation was produced by a mobile test phone (model NOKIA 3110; Nokia Mobile Phones Ltd.) connected to a Communication Test Set (model 4202S; Wavetek, Germany). A 900 MHz electromagnetic near-field signal for GSM (Global System for Mobile communication at 900 MHz, continuous wave, analog phone) system was used. The whole-body specific energy absorption (SAR) rate was estimated as 0.025-0.05 W/kg (E=9.8-18.3 V/m, B=4.8-8.6 µT). Rats were sacrificed after 3 months of MWR exposure. The liver and brain were fixed in 10% formaldehyde and paraffin sections were stained by HE. The biochemical analyses comprised the determination of serum activity of AST (Aspartate aminotransferase), ALT (Alanine transaminase), GGT (Gamma-glutamyl transpeptidase) and LDH (Lactate dehydrogenase), as well as determination of serum concentration of sodium, potassium and chloride. Lipid peroxidation was determined by measuring the quantity of malondialdehyde (MDA).Slightly increased number of micronuclei and discrete perivenular fatty changes were only histopathological findings in the liver of exposed rats. The discrete reduction of gray matter and reduced size and number of dendritic spines of Purkinje cells in cerebellum were notified as well. The serum activity of ALT was significantly increased (p<0.05), while activities of AST, GGT and LDH did not changed in the exposed rats. Potassium serum concentration was significantly higher in the exposed rats, while the concentration of sodium and chloride did not differ. The MDA concentration was significantly higher in the brain and liver tissues of MWR-exposed rats.The results in this study show significant increase in lipid peroxidation as a direct indicator of the hepatocytes and brain cells’ injury under a long-term (90 days) mobile phone microwave exposure. The hyperkalemia could be the possible systemic marker of impaired cells membrane fluidy and increased permeability, alongside with increased ALT activity as marker of hepatocelular damage. Disorders of hypothalamo- hypophyseal axis lead to disturbances in affective behaviour, but also to disturbances of neurovegetative functions, which leads to behavioral changes and increased appetite and weight gain in exposed animals

Uticaj opterećenja različitim nivoima profesionalnog stresa na koncentraciju serumskih lipida službenika obezbeđenja

The aim of this work is to analyze the relationship between the level of professional stress and the concentration of total cholesterol, HDL cholesterol, LDL cholesterol and triglycerides in the serum of security employees. . The study included 415 security officers (exposed group) divided into four sub-groups and 150 administrative workers (control group). By applying a standardized questionnaire, the level of professional stress in their workplaces was calculated. To determine the serum lipid concentration in the all subjects, venous blood samples were taken in the morning after a twelve-hour food abstinence Security officers are exposed to a high level of professional stress, where the level of stress index depends on the type of the job they are engaged in. The highest values of the total index of professional stress, total cholesterol, LDL cholesterol and triglycerides were registered with the employees who transport money and those carrying firearms. The lowest total index of professional stress, total cholesterol, LDL cholesterol and triglycerides were registered with property security officers and persons who do not carry firearms. The correlation between the level of stress index at work, an increase in total cholesterol, LDL cholesterol, triglycerides and HDL cholesterol levels is statistically significant. We believe that there is a significant correlation between the level of the overall stress index at work and the risk of atherosclerosis in security officers.Cilj rada je analiza povezanosti nivoa profesionalnog stresa i koncentracija ukupnog holesterola, HDL holesterola, LDL holesterola i triglicerida u serumu službenika angažovanih na različitim vrstama obezbeđenja. Ispitivanjem je obuhvaćeno 415 službenika obezbeđenja (ispitivana grupa) podeljenih u četiri podgrupe i 150 administrativnih radnika (kontrolna grupa). Primenom standardizovanog upitnika, je izračunavan nivo profesionalnog stresa na njihovim radnim mestima. Radi određivanja koncentracije lipida u serumu od svih ispitanika je uziman uzorak venske krvi ujutru posle dvanaestočasovne apstinencije od hrane. Službenici obezbeđenja su izloženi visokom nivou profesionalnog stresa, pri čemu nivo indeksa stresa zavisi od vrste poslova na kojima su angažovani. Najviše vrednosti ukupnog indeksa profesionalnog stresa, ukupnog holesterola, LDL holesterola i triglicerida su registrovane kod službenika na obezbedjenju transporta novca sa nošenjem vatrenog oružja. Najniže vrednosti ukupnog indeksa profesionalnog stresa, ukupnog holesterola, LDL holesterola i triglicerida su registrovane kod službenika na obezbedjenju imovine i lica bez nošenja vatrenog oružja. Utvrđena je statistički značajna korelacija između nivoa indeksa stresa na poslu, povećanja vrednosti ukupnog holesterola, LDL holesterola, triglicerida i smanjenja nivoa HDL holesterola. Smatramo da postoji značajna povezanost između nivoa ukupnog indeksa stresa na poslu i rizika od ateroskleroze kod službenika obezbeđenja

The influence of professional stress in permanent working capability of workers with arterial hypertension and its complications

Arterial hypertension is widespread in the population of workers. Stress at work has a significant impact on the emergence of many psychosomatic diseases including arterial hypertension. The aim of this research is to show the influence of professional stress on the occurrence of arterial hypertension, its complications and the permanent working ability of exposed workers in construction. The survey covered 1900 construction workers. The standardized questionnaire has assessed the level of stress and professional stressors in their workplaces. The survey group consisted of 1350 workers whose level of total professional stress index (OSI) was over 60, and a control group of 550 workers with an OSI level below 60. The prevalence of arterial hypertension and its complications is statistically significantly more frequent in the examined than in the control group. In the investigated group, a statistically significant number of workers were registered, who, due to their complete loss of working ability, were sent to the disability commission. With an increase in OSI values above 71, the number of workers with complete loss of working capacity is significantly increased in relation to the number of workers who are capable of working. Professional stress is a significant factor that affects the occurrence of arterial hypertension, its complications on vital organs, which lead to a complete permanent loss of working ability of exposed workers in construction

Smoking habits, knowledge about and attitudes toward smoking among employees in health institutions in Serbia

Background/Aim. According to the number of active smokers, Serbia occupies a high position in Europe, as well as worldwide. More than 47% of adults are smokers according to WHO data, and 33.6% according to the National Health Survey Serbia in 2006. Smoking physicians are setting a bad example to patients, they are uncritical to this habit, rarely ask patients whether they smoke and rarely advise them not to smoke. These facts contribute to the battle for reducing the number of medical workers who smoke, as well as the number of smokers among general population. The aim of the study was to determine the smoking behavior, knowledge and attitudes and cessation advice given to patients by healthcare professionals in Serbia. Methods. A stratified random cluster sample of 1,383 participants included all types of health institutions in Serbia excluding Kosovo. The self administrated questionnaire was used to collect data about smoking habits, knowledge, attitudes and cessation advice to patients given by health professionals in Serbia. Results. Out of 1,383 participants, 45.60% were smokers, of whom 34.13% were physicians and 51.87% nurses. There were 46.4% male and 45.4% female smokers. The differences in agreement with the statements related to the responsibilities of health care professionals and smoking policy are significant between the “ever” and “never” smokers, and also between physicians and nurses. Twenty-five percent of nurses and 22% of doctors claimed they had received formal training. However, only 35.7% of the healthcare professionals felt very prepared to counsel patients, while 52.7% felt somewhat prepared and 11.6% were not prepared at all. Conclusions. According to the result of this survey, there are needs for more aggressive nationwide non-smoking campaigns for physicians and medical students. Experiences from countries where physicians smoke less and more effectively carry out smoking cessation practices need to be shared with Serbian physicians in order to improve their smoking behavior and smoking cessation practices. [Projekat Ministarstva nauke Republike Srbije, br. 43012

CD34 AND C-KIT IMMUNOREACTIVE CELLS IN THE HUMAN EMBRYONAL AND FETAL SMALL BOWEL

Interstitial cells of Cajal (ICC) play important roles in the control of digestive motility: they generate the electrical slow-wave activity (pacemaker component) of the gut musculature and are involved in neurotransmission and stretch sensation. ICC expresses c-kit and depends on signaling via Kit receptors for development and maintenance of phenotype. The aim of the present study was to investigate if the c-kit immunoreactive (IR) cells present in the wall of the small bowel at the beginning of the fetal period are CD34 immunopositive. Human small bowel specimens were obtained from 5 embryos and 7 foetuses, 7–12 weeks of gestational age. The specimens were exposed to anti-c-kit antibodies to investigate ICC differentiation and anti-CD34 antibodies to identify presumed ICC progenitors. The differentiation of smooth muscle cells was studied with anti-desmin antibodies. At 9–10 weeks, c-kit IR cells were present in the wall of small bowel in the form of a narrow band of cells, at the level of the myenteric plexus, but they were absent in the mucosa and submucosa of the gut. At the same time, CD34 IR cells were present at the level of submucosa and mucosa, and they were not present in the outer parts of gut wall. A clear distinction between the localization of c-kit IR cells and CD34 IR cells was evident. We may conclude that c-kit IR cells present in the small bowel wall at the beginning of fetal period of development, at 9–10 weeks, do not exhibit concurrent CD34 immunoreactivity.Key words: Small bowel, c-kit, CD-34, immunohistohemistry, huma

Model za predviđanje bioloških efekata zračenja mobilnih telefona: numerički rezultati apsorbirane energije povezani s realnom strukturom dobivenom metodom MRI

The nature of an electromagnetic field is not the same outside and inside a biological subject. Numerical bioelectromagnetic simulation methods for penetrating electromagnetic fields facilitate the calculation of field components in biological entities. Calculating energy absorbed from known sources, such as mobile phones when placed near the head, is a prerequisite for studying the biological influence of an electromagnetic field. Such research requires approximate anatomical models which are used to calculate the field components and absorbed energy. In order to explore the biological effects in organs and tissues, it is necessary to establish a relationship between an analogous anatomical model and the real structure. We propose a new approach in exploring biological effects through combining two different techniques: 1) numerical electromagnetic simulation, which is used to calculate the field components in a similar anatomical model and 2) Magnetic Resonance Imaging (MRI), which is used to accurately locate sites with increased absorption. By overlapping images obtained by both methods, we can precisely locate the spots with maximum absorption effects. This way, we can detect the site where the most pronounced biological effects are to be expected. This novel approach successfully overcomes the standard limitations of working with analogous anatomical models.Numeričke bioelektromagnetne simulacijske metode prodrlih elektromagnetnih polja koriste se za izračunavanje komponenata polja u biološkim jedinkama. Elektromagnetno polje nije jednako izvan i unutar biološkog subjekta. Izračunavanje energije apsorbirane iz poznatog izvora, kao što su mobilni telefoni u području glave, preduvjet je za ispitivanje biološkog utjecaja elektromagnetnog polja. Pri ovim istraživanjima koriste se približni anatomski modeli i na osnovi njih se izračunavaju komponente polja i apsorbirana energija. Nužno je uspostaviti vezu između odgovarajućih približnih anatomskih modela s realnom strukturom, kako bi se mogli istraživati biološki efekti u dijelovima organa i tkiva. Zbog toga se u ovom radu predlaže novi pristup istraživanju bioloških efekata. U osnovi metode je kombinacija dviju različitih tehnika: 1) numeričke elektromagnetne simulacije kojom se izračunavaju komponente polja u približnom anatomskom modelu i 2) MRI metoda (Magnetic resonance imaging) kojom se precizno lociraju mjesta s povišenom apsorpcijom. Kombiniranje se postiže preklapanjem slika dobivenih jednom i drugom metodom, čime se utvrđuje precizna lokacija mjesta s maksimalnim efektima apsorpcije. Na taj način mogu se pronaći mjesta na kojima bi trebao biti najizraženiji biološki učinak. Novi pristup uspješno prevladava ograničenja koja su postojala pri radu s približnim anatomskim modelima

Oregano (Origanum vulgare) essential oil prevents L-arginine-induced rat ileum villi damage

Oregano (Origanum vulgare L., Lamiaceae) is used for centuries as a culinary spice due to its food flavor enhancing properties and its specific aroma. Essential oil isolated from oregano is known to affect the function of the gastrointestinal system by causing stomach and throat smooth muscle relaxation. The present work aims to evaluate the potential protective effects of oregano essential oil in rat ileum intestinal mucosa injury, induced with high doses of L-arginine, by tracking pathological changes in ileum mucosa. Male Wistar rats, divided into four groups (n=6), were treated with 50 mg/kg of oregano essential oil or 200 mg/kg of allopurinol (xanthinoxidase inhibitor) 1 h before a single dose of L-arginine (3.5 g/kg). Two groups served as the controls – one treated with a single dose of L-arginine, while the second group of animals remained untreated. One day after the treatment, all animals were sacrificed and the segments of distal ileum were dissected and fixed in 10% buffered formalin solution. Afterward, the tissue was processed routinely in order to obtain paraffin molds which were further cut into 4-5 µm thin sections and stained with hematoxylin and eosin. Microscopic analysis of the control group ileum revealed short and cylindrical villi, with great resemblance to fingers, with no pathological substrate present. Ileum villi from the group of animals treated only with L-arginine appeared swollen, with the villi tip significantly dilated. Also, in the lamina propria, a large number of leucocytes were visible. The application of both allopurinol and oregano essential oil was able to prevent such significant alterations in the intestinal villi appearance (both in its intensity and frequency) and to reduce the number of leucocytes that migrated to the lamina propria. The detected activity can possibly be attributed to numerous oil constituents found in this essential oil, but predominantly to its major constituents thymol and carvacrol