Interdisciplinary crossover for rapid advancements: Collaboration between medical and engineering scientists with the focus on Serbia

Napretku medicine su poslednjih decenija veoma mnogo doprineli pronalasci iz različitih oblasti inženjerstva. Polovinom dvadesetog veka uspostavlja se nova naučna oblast, biomedicinsko inženjerstvo (BI), koje se do sada razvilo u veoma složenu naučnu disciplinu koja je zahtevala i poseban obrazovni profil. Na univerzitetima širom sveta, kao i na nekoliko univerziteta u Srbiji ustanovljeni su različiti programi iz oblasti biomedicinskog inženjerstva. Takođe, u nekoliko naučnih institucija u Srbiji sprovode se intenzivna istraživanja u ovoj oblasti. U ovom radu prikazani su rezultati istraživanja nekoliko grupa naučnika iz oblasti inženjerstva i medicine sa ciljem da se ilustruje koliko je široko polje istraživanja u oblasti biomedicinskog inženjerstva i kakve su mogućnosti njihove primene u dijagnostici i lečenju različitih bolesti.Over the past decades, development of engineering sciences has vastly contributed to advancements in medicine by production of numerous devices for diagnostics and treatment. In the middle of the 20th century, a new scientific field, biomedical engineering (BE), was established, which has developed into an extremely complex scientific discipline requiring a distinctive educational profile. Various study programs in BE have been established at universities around the world but also at several universities in Serbia. Also, intensive research in this field is performed at several scientific institutions in Serbia. In the present paper, short summaries of the research results of several groups of engineers and medical doctors are presented as an illustration of the wide field of BE research and possibilities of its application in diagnosis and therapy of various diseases

Antioxidative properties and antigenotoxic potential of Gentiana lutea extracts against the heterocyclic aromatic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine, PhIP

Lipid oxidation that occurs in different types of food can cause alterations in nutritional qualities, flavour, texture and shelf life of foods. Furthermore, high temperature cooking of protein-rich food can lead to formation of heterocyclic aromatic amines capable of compromising the integrity of DNA molecules. To reduce these harmful effects, research has been focused on investigating plants as a source of potential natural food additives and preservatives. Thus, the aim of this study was to estimate antioxidant and antigenotoxic activities of 50% ethanolic-aqueous root and leaf extracts of the medicinal plant, Gentiana lutea . Antioxidative effect was investigated using the DPPH assay, while antigenotoxicity against the mutagen 2-amino-1-methyl-6-phenylimidazo[4,5- b ]pyridine (PhIP) was determined using Salmonella Typhimurium TA 1535 in the SOS/ umuC assay. Leaf extract showed high antioxidative effect with the ability to neutralize up to 87% of free radicals at 400 µg mL -1 . Antigenotoxicity testing revealed that both extracts exhibited remarkable genoprotective activity against PhIP-induced DNA damage, with the highest inhibition levels being 70% and 85% for root and leaf extracts, respectively. Results obtained are encouraging and suggest further research of G. lutea extracts as potential food preservatives and additives in improving food quality and human health

Usporavaenje progresije hronične insuficijencije bubrega kaptoprilom kod pacova sa spontanom arterijskom hipertenzijom i adriamicinskom nefropatijom

In SHRs with ADR nephropathy treatment with captopril normalized systemic blood pressure, and slowed down CRF progression in their early stage. These functional changes correlate with significant slowing of glomerular and interstitial changes.Uticaj arterijske hipertenzije na progresiju hronične insuficijencije bubrega opisan je u brojnim eksperimentalnim i kliničkim studijama. Samim tim uticaj različitih antihipertenzivnih lekova ka regulisanju pritiska krvi i usporavaju progresne hronične insuficijencije bubrega još uvek je predmet rasprava i neslaganja mnogih naučnika. Cilj ovog rada bio je da se ispita uticaj kaptoprila na kliničke, biohemijske i morfološke promene kod pacova sa spontanom arterijskom hipertenzijom i nefropatijom izazvanom adriamicinom. Šezdeset i devet ženki pacova sa spontanom arterijskom hipertenzijom (stare 24 nedelje) svrstane su u tri grupe: 1. kontrolna grupa - 12; 2. grupa s nefropatijom izazvanom adriamicinom - 27 sa spontanom arterijskom hipertenzijom koja je tretirana adriamicinom (2 mg/kg i.V. dva puta u 20 dana); 3. grupa s nefropatijom izazvanom adriamicinom - grupa S: 30 sa spontanom arterijskom hipertenzijom tretirana adriamicinom i kaptoprilom (60 mg/kg dnevno). Sistolni pritisak krvi meren je na dve nedelje, a analize seruma i urina na početku studije i u 6-oj, 12. i 18. nedele posle druge injekcije adriamicina. Životinje su žrtvovane 6-e, 12. i 18. nedelje od početka tretiranja kaptoprilom. Patomorfološke promene prikazane su semikvantitativno izračunavanjem indeksa glomerula vaskularnog indeksa, kao i indeksa fibroze intersticijuma i infiltracije, i atrofije tubula. Kaptopril je normalizovao sistemski pritisak krvi, ali nije smanjio proteinuriju kod pacova sa spontanom arterijskom hipertenzijom. Ureja i kreatinin u serumu progresivno su rasli u svim ispitivanim grupama pacova, ali brže kod pacova koji su tretirani adriamicinom. Klirens kreatinina najbrže je opadao u grupi kod pacova s nefropatijom izazvanom adriamicmom. Kaptopril smanjuje promene u glomerulima kod pacova sa spontanom arterijskom hipertenzijom i nefropatijom izazvanom adriamicinom s visokom statističkom značajnošću u 18-oj nedelji studije. Promene u intersticijumu kod pacova sa spontanom arterijskom hipertenzijom koji su tretirani adriamicinom uvećavaju ce u toku ogleda, ali statistički značajno sporije u svim nedeljama studije u grupi pacova s nefropatijom izazvanom adriamicinom (grupa C) Kaptopril nije uticao na promene u tubulima kod ovih životinja

Antibacterial activity of aqueous-ethanolic extracts of Alchemilla vulgaris and Frangula alnus combined with streptomycin

The harmful effects that antibiotics may have on human health and increased resistance of microorganisms on antibiotics made pharmaceutical companies look for new alternatives among medicinal and aromatic plants. Recently, as a new strategy to enhance antimicrobial activities of commercial antibiotics, the combination of plant extracts and antibiotics is developing. The aim of the study was to examine the potential synergistic effect of plant extracts with streptomycin. The minimum inhibitory concentration of two extracts obtained from traditional medicinal plants, Alchemilla vulgaris and Frangula alnus, was determined by the microdilution method. The effect of a mixture of extracts and antibiotics was tested with checkerboard assay and confirmed by Time kill assay. The most sensitive strain was E. coli ATCC 25922

Levels of Presepsin and Midregion-Proadrenomedullin in Septic Patients with End-Stage Renal Disease after Cardiovascular Surgery: 1-Year Follow Up Study

Background: Procalcitonin (PCT) is a marker for sepsis diagnosis, identification of bacterial infection and monitoring of antibiotic therapy. It has been shown that PCT is not a good choice in patients with hemodialysis. Therefore, we have explored two biomarkers: a) presepsin, and, b) midregion-proadrenomedullin (MR-proADM) in patients having End-Stage Renal Disease (ESRD). Patients and Methods: We prospectively enlisted 20 patients, who underwent cardiovascular surgery and had been on dialysis. The diagnosis of sepsis has been established clinically and confirmed by PCT. Blood samples were taken before and after dialysis. Additionally, plasma and sera of 10 healthy blood donors without any complications were used as controls. Results: Presepsin plasma concentrations (4368 ± 3088 vs. 694.1 ± 239.1 pg/mL) were significantly higher in patients with sepsis compared with controls (p0.05) with no significance between alive and deceased (p=0.53) patients. Adjustments have shown that the difference for MR-proADM level is due to the random sampling variability (p=0.989), whereas difference for presepsin remained highly significant (p<0.001). Conclusions: Our results indicate that the accuracy of new biomarkers is equal to that of PCT in patients with ESRD. Presepsin might be as good marker in repeated measurements, before and after dialysis, as it is PCT. © 2014 Maravic-Stojkovic V, et al

Endotel-zavisna relaksacija unutrašnje torakalne arterije prouzrokovana rezveratrolom

Resveratrol, a polyphenol present in wine, has been thought to be responsible for cardiovascular benefits associated with moderate wine consumption. It is also present in the plant Polygonum Cuspidatum. The mechanism of cardiovascular benefits probably includes vasorelaxation, antioxidant and anti-platelet effects of resveratrol. The mechanisms by which resveratrol causes vasodilatation are uncertain. The aim of this study was to investigate the mechanism(s) of resveratrol induced vasorelaxation in human internal mammary artery (HIMA) with endothelium. HIMA rings were precontracted by phenylephrine. Resveratrol induced relaxation of the HIMA rings with endothelium. LNAME, an inhibitor of NO synthase, and methylene blue, an inhibitor of guanylate cyclase, abolished relaxation of HIMA induced by resveratrol. Highly selective blocker of ATP-sensitive K channels, glibenclamide as well as a nonselective blocker of big Ca-sensitive K+ channels, charybdotoxin did not block resveratrol-induced relaxation of HIMA. 4-Aminopyridine and margatoxin, blockers of voltage-gated K+ (KV) channels, abolished endothelium-dependent relaxation of HIMA, induced by resveratrol. In conclusion, we have shown that resveratrol induces relaxation of HIMA with endothelium. It seems that NO and smooth muscle KV channels are included in this relaxation.Smatra se da rezveratrol kao jedna polifenolna komponenta prisutna u značajnim količinama u crnom vinu, smanjuje rizik od razvoja ateroskleroze i koronarne bolesti. U mehanizam kardioprotektivnog delovanja verovatno su uključ eni antioksidativno, antitrombocitno i vazodilatatorno delovanje rezveratrola. Mehanizam vazodilatacije još uvek nije poznat, pa je cilj ovog rada bio da se ispitaju efekti i mehanizam vazorelaksantnog delovanja rezveratrola na humanoj unutraš njoj torakalnoj arteriji sa endotelom. Unutrašnja torakalna arterija je prekontrahovana fenilefrinom. Rezveratrol je koncentracijski-zavisno relaksirao unutrašnju torakalnu arteriju čoveka. L-NAME, inhibitor NO sintaze, i metilensko plavo, inhibitor solubilne gvanilat ciklaze, su antagonizovali relaksaciju unutrašnje torakalne arterije sa intaktnim endotelom, prouzrokovanu rezveratrolom. Visoko selektivni blokator ATP-senzitivnih K+ kanala, glibenklamid, kao i neselektivni blokator velikih Ca-senzitivnih K+ kanala, karibdotoksin nisu antagonizovali rezveratrolom indukovanu relaksaciju unutrašnje torakalne arterije. 4-Aminopiridin i margatoksin, blokatori voltažnih K+ kanala su antagonizovali relaksaciju prouzrokovanu rezveratrolom. Na osnovu ovih činjenica se može zaključiti da je endotel-zavisna relaksacija unutrašnje torakalne arterije čoveka, prouzrokovana rezveratrolom, verovatno posredovana NO. Izgleda, da su 4-aminopiriin- i margatoksin-senzitivni K-kanali smešteni u membrani vaskularnih glatko-mišićnih ćelija humane unutrašnje torakalne arterije, uključeni u mehanizam endotel-zavisne relaksacije prouzrokovane rezveratrolom

The radial artery for coronary artery bypass grafting

Coronary artery bypass grafting (CABG) is the standard surgical procedure for the treatment of advanced coronary artery disease. CABG surgery has been demonstrated to improve symptoms and, in specific subgroups of patients, to prolong life. Despite its success, the long-term outcome of coronary bypass surgery is strongly influenced by the fate of the vascular conduits used. Previous long-term studies have shown unsatisfactory patency of saphenous vein grafts used for myocardial revascularisation, compared with internal mammary artery grafts. Recently, the use of radial artery for CABG has enjoyed a revival, on the basis of the belief that it will help improving long-term results of coronary operations. The recent reports of encouraging mid-term and long-term patency rates of the radial artery, supports its continued use as a bypass conduit. In this paper, we review the current knowledge about the radial artery as a bypass graft, with special emphasis on the clinical results.Hirurška revaskularizacija miokarda je standardna procedura u tretmanu uznapredovale koronarne bolesti. Dokazano je da koronarna hirurgija uklanja simptome i produžava život određenih kategorija koronarnih bolesnika. Dugotrajni rezultati hirurške revaskularizacije miokarda u velikoj meri ovise o promenama koje se vremenom javljaju na upotrebljenom graftu. Studije dugoročnog praćenja operisanih bolesnika potvrdile su izuzetan kvalitet i prednost grafta unutarnje torakalne arterije u odnosu na venski graft. U skorije vreme obnovljeno je interesovanje za graft radijalne arterije, sa uverenjem da će njegova primena omogućiti bolje dugoročne rezultate. U poslednje vreme prikazani su radovi koji potvrđuju izuzetnu kratkoročnu i dugoročnu prohodnost grafta radijalne arterije i govore u prilog intenzivnije primene toga grafta u hirurškoj revaskularizaciji miokarda. Na prikaz je pregled sadanjih saznanja o radijalnoj arteriji kao graftu u kardiohirurgiji, sa posebnim osvrtom na kliničke rezultate

Analysis of operation of the condenser in a 120 MW thermal power plant

The condenser plant has a huge impact on the economy of a steam turbine power plant. Deterioration of the parameters during operation could lead to a significant decrease in electrical output and to an increase in the heat rate of the thermal power plant. Detailed calculations of the performance under different operating conditions were carried out for the condenser of the Morava thermal power plant. Comprehensive testing of the condenser was carried out and experimental data were compared with the numerical results. The effects of deviations in the condenser behaviour on the main thermodynamic parameters and the overall economics of the power plant were evaluated. Guidelines for operation of condensation plants are given in the conclusion

Serum cystatin C as a measure of GFR in renal transplant patients

INTRODUCTION Assessment of renal function is of great importance in clinical medicine, especially in renal transplant patients requiring frequent controls of renal function. Therefore, continuous efforts have been made in searching precise and simple method for determination of glomerular filtration rate (GFR). Serum level of cystatin C (CyC), protein of low molecular weight, has been proposed as measure of GFR, but the data of its value in renal transplant patients are scarce [8-10]. PURPOSE The aim of this study was to compare the serum levels of low molecular weight proteins CyC and ß2-microglobulin (ß2-MG) with creatinine clearance, as well known measure of GFR, in renal transplant patients and control group of patients with different renal disease. PATIENTS AND METHODS The study included 36 patients divided into two groups. Group 1: 20 renal transplant patients (12 men and 8 women) aged between 22 and 63 (40.4±10.1) years with creatinine clearance from 7.1 to 77.7 ml/min. Group 2: 16 controls (5 men and 11 women) with various renal diseases, aged between 24 and 63 (41.5±12.5) years with creatinine clearance from 60.5 to 116.8 ml/min. N Latex Cystatin C and ß2-microglobulin for the Behring Nephelometer System was used in this study. Creatinine was determined with Jaffe-reaction in serum and urine. RESULTS In renal transplant patients as well as in control group of patients the significant correlation between creatinine clearance and reciprocal values of the serum CyC (rt=0.828; pt&lt;0.001; rc=0.603; pc&lt;0.05) and reciprocal values of the serum ß2-MG levels (rt=0.791; pt&lt;0.001; rc=0.627 pc&lt;0.05) was found (Graph 1). There was a slightly better correlation between creatinine clearance and reciprocal values of the serum CyC than the one between creatinine clearance and reciprocal values of the serum ß2-MG without statistical significance in renal transplant patients. There was no difference in correlation coefficients between both low molecular weight proteins and creatinine clearance in Group 2. The correlation coefficient between serum CyC and ß2-MG was r=0.839(p&lt;0.001)in renal transplant patients and r=0.835 (p&lt;0.05) in control group. There were no significant differences in correlation coefficients between reciprocal values of serum CyC and creatinine clearance (p=0,2043) as well as reciprocal values of serum ß2-MG and creatinine clearance (p=0.3717) between Group 1 and Group 2. DISCUSSION In renal transplant patients rapid assessment of graft function is necessary. This allows early recognition of rejection as well as differential diagnosis of different renal graft disorders. Study of Risch and co [16] suggested that serum CyC was very good marker for GFR in renal transplant patients which was confirmed by the other authors too [20-22]. During inflammatory process or other pathological conditions, especially during acute rejection or infections, CyC also provided precise assessment of GFR while creatinine clearance varied dramatically [16], Serum concentration of ß2-MG, another low molecular weight protein, also depends both on its production rate and the GFR [5,19]. Its production is dramatically different in patients with infections [5] as well as while immunosuppressive drugs are used [16], Therefore, ß2-MG is impractical as GFR marker in patients with renal transplants. So, serum CyC was considered as better marker for GFR than ß2-MG and creatinine clearance in renal transplant patients with different complications [16], In this study serum CyC was slightly better marker for GFR than ß2-MG, without statistical significance (Graph 1). Renal transplant patients, however, were in the stable condition at the time of the study. CONCLUSION Serum CyC was moderately better marker of GFR than ß2-MG in renal transplant patients when they were in the stable condition. Serum CyC and ß2-MG were the same markers of GFR in control group of patients with various renal diseases. There was no significant difference in correlation coefficients between reciprocal values of the serum CyC and creatinine clearance (p=0.2043) as well as reciprocal values of the serum ß2-MG levels and creatinine clearance (p=0.3717) between two examined groups of patients. The studies on renal transplant patients with acute graft rejection or infections are warranted