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Background/Aim. Epidemiological studies of renal biopsies have been performed to follow up the incidence of glomerular diseases on a specified territory and to compare the obtained results with results from other regions. The aim of this study was to analyze the frequency of certain histopathophysiological types of glomerular diseases on the territory of Southeast Serbia. Methods. In a 20-year period (1986-2006), 316 kidney biopsies were performed in patients with clinicall signs of impaired renal function, in Southeast Serbia. On average 1.6 biopsies were made per year per 100 000 inhabitants. Results. Biopsies of adult patients represented 88% of all biopsies, biopsies in children (aged under 18 years) represented 8%, while biopsies of elderly patients (more than 60 years) represented 4% of all biopsies. The predominance of male patients was described with male/female ratio of 1.4. The most frequent clinical manifestation in patients at the time of biopsy were nephrotic syndrome (42.5%), and asymptomatic proteinuria and/or hematuria (31.3%) and nephritic syndrome (14.9%). The most common glomerular disease was IgA nephropathy with an incidence of 21.5% of total biopsy diagnosed glomerulopathies, followed by: membranous glomerulonephritis (12.6%), focal segmental proliferative and sclerosing glomerulonephritis (10.7%), lupus nephritis (8.4%), nephroangiosclerosis (7.0%), mesangio-proliferative glomerulonephritis (6.1%), minimal change disease (2.8%), mesangiocapillary glomerulonephritis (2.3%). Conclusion. The frequency of certain histopathologic findings significantly correlated with data from studies that we used for comparison, with the exception of minimal change disease whose incidence in our study was smaller.

Balkan endemic nephropathy (BEN) presents an unsolved puzzle despite fifty years of its investigation. Academy of Medical Sciences of the Serbian Medical Society organized a round table discussion on current unsolved problems related to BEN. The present paper summarizes presentations, discussion and conclusions of this meeting. During the last fifty years, the course of BEN prolonged and it shifted towards the older age in all endemic foci. Data on the incidence of BEN have been controversial and frequently based on the data on the number of BEN patients starting haemodialysis treatment. In Serbia, BEN patients present 6.5% of haemodialysis population and this percentage differs among different centres ranging from 5% (Leskovac) to 46% (Lazarevac). Maintenance of high prevalence of BEN patients on regular haemodialysis indicates that BEN is not an expiring disease. In addition, recent data have shown more frequent microalbuminuria and low-molecular weight proteinuria in children from endemic than from nonendemic families. Aetiology of BEN is still unknown despite numerous investigations of environmental and genetic factors. Today, there is a very current hypothesis on the aetiological role of aristolochic acid but the role of viruses, geochemical factors and genetic factors must not be neglected. Morphological features of BEN are nonspecific and characterized by acellular interstitial fibrosis, tubular atrophy and changes on preand postglomerular vessels. New immunohistochemical and molecular biology methods offer a new approach to BEN investigation. Association of BEN with high incidence of upperurothelial tumours is well-known. Recent studies have shown significant changes of demographic characteristics of patients suffering upper-urothelial tumours, their prevalence in different endemic foci and characteristics of tumours. Further studies of BEN should be directed to determination of incidence and prevalence of disease in different endemic foci, investigations of different insufficiently examined aetiological factors as well as pathomorphological features of the disease by the use of modern methods.

Introduction. Analysis of macromorphological and ultrastructural tooth characteristics of osteological material from the medieval site of St. Pantaleimon Church in Nis provides us with insight on the life, nutrition and habits of medieval population, as well as the structure and composition of their teeth. Objective. The aim of this research, based on the tooth inspection of skeletal remains from the medieval site of St. Pantaleimon Church in Nis, was to analyze macromorphological characteristics , ultrastructure of the dental tissue of maxillary and mandibular molars, canines and incisors, as well as their chemical composition. Methods. Macromorphological and ultrastructural analysis of the dental tissue of osteological material dating from the 12th century included 1312 teeth with advanced abrasion. Macromorphological changes were detected by using a dental mirror, probe and radiography. After irrigation, the teeth were prepared using the standard procedure and analyzed by scanning electronic microscopy (JEOL-JSM-5300). Chemical analysis was done by expanded downscaling (EDS) method for Mg, P, Ca. Results. The analysis detected second degree abrasions of all teeth in individuals aged 20-25 years. Third and fourth degree abrasions of teeth were detected in individuals aged over 40 years. Ultrastructural analysis showed a complete obliteration of dentin tubules and pulp of the lower incisors, the apposition of intratubular dentin inside the tubules, as well as extensive deformity and loss of dentin structure on molars with preserved pulp volume and nerve fiber calcification. The calcification of nerve fibers showed that the formation of intratubular dentin was proportional with the biological potential of pulp and the degree of abrasion, and inversely proportional with the size of dentin surface. Chemical analysis showed that in the analyzed teeth Ca composition was slightly lower than that in the control group, P composition was almost identical, while Mg composition was multiply increased in comparison to the control group consisting of today’s persons of matching age and examined teeth as the medieval individuals. Conclusion. Different ultrastructural tooth characteristics as a part of the complex masticatory system of the medieval man are the result of individual and the whole community adaptation to actual living conditions. Nerve fibers calcification of the pulp can explain the absence of pain despite the high level of dental abrasion.

INTRODUCTION. Hereditary nephropathy is clinically characterized by the familial occurrence in successive generations of progressive haematuric nephritis and neural hearing loss. Hereditary nephropathy of Alport’s syndrome (AS) and benign familial (recurrent) haematuria (BFH) are morphologically characterized by specific and diagnostically important thickening and splitting of lamina densa of the glomerular basement membranes. Those lesions can be recognized only by electron microscopy. Hereditary nephritis is usually present clinically with haematuria, and new mutations without a family history of haematuria. It is therefore important to differentiate hereditary nephritis from BFH and no familial haematuria. Thus, electron microscopy is essential in diagnosis of haematuria. OBJECTIVE. The aim of this study was to describe, by light microscopy, constellation of renal alterations by which hereditary nephropathy can be recognized with high probability as well as to compare the diagnostic validity of the findings observed by light and electron microscopy in AS and BFH. METHOD. We examined 48 renal biopsies of the patients with hereditary nephoropathies by light and electron microscopy. Tissue samples were fixed in buffered paraformaldehyde and embedded in paraffin for long-term preservation. For the electron microscopy analysis, the following fixation in 4% glutaraldehyde tissue was postfixed in 1% osmium tetroxide. Thereafter, the following dehydration procedure tissue slices were embedded in epon. RESULTS. Our results demonstrated that the interstitial foam cells, foetal-like glomeruli, minimal glomerular abnormalities with stain less intense in basement membranes, mild irregular mesangial widening, focal thickening of Bowman’s capsule, foci of dilatation tubules, tubular ectasia and atrophy, erythrocyte tubules casts were present in hereditary nephritis. Additionally, light microscopic biopsy findings in patients with BFH were either normal or revealed minor changes (e.g. increased mesangial matrix). All biopsies were reevaluated by electron microscopy and ultrastructural findings confirmed the diagnosis of hereditary nephropathies. CONCLUSION. The findings observed by light microscopy represent an important step that leads to a definitive diagnosis of AS and BFH. The definitive diagnosis, however, depends on electron microscopy.

Glomerulus is an important filtrating apparatus in the body. Three types of cells - endothelial, mesangial and visceral epithelial cells can be identified in the capillary tuft. Glomeruli develop during nephrogenesis which starts in the 8th week and ends between the 32nd and 36th week of gestation. The nephron develops through stages described as the vesicle, the comma-shaped, S-shaped with the developing glomerulus and the mature glomerulus. Glomerular differentiation involves the expansion of the original capillary component into the plexus that consists of 6-8 loops and the migration of podocytes that are arranged around these glomerular capillaries. Glomerular capillary differentiation represents a set of developmental changes of the glomerular endothelial and epithelial cells. The active differentiation of glomerular capillaries starts in the hemisphere of an inferior arm of S-shaped bodies. Endothelial precursors unite into precapillaries devoid of lumen. Further differentiation includes the flattening of endothelial cells on the basement membrane, the loss of superfluous cells, the development of lumen and the formation of fenestrae. The glomerular basement membrane is differentiated by the fusion of epithelial and endothelial basement membrane. The differentiation of visceral epithelial cells includes the development of cytoplasmic processes and the flattening of cell bodies. Primary cytoplasmic processes are formed from the podocyte bodies and develop secondary and tertiary processes or foot processes. Foot processes from one podocyte interdigitate with foot processes from other podocytes. In the developing glomeruli, there is a difference in the level of differentiation of visceral epithelial cells. Cells with differentiated foot processes and cells with no cytoplasmic processes are observed within the same glomerulus.

The alveolar bone tissue resorption defect has a significant role in dentistry. Because of the bone tissue deficit developed by alveolar resorption, the use of synthetic material CP/PLGA (calcium-phosphate/polylactide-co-gliycolide) composite was introduced. Investigations were performed on rats with artificially produced resorption of the mandibular bone. The results show that the best effect on alveolar bone were attained by using nano-composite implants. The effect of the nanocomposite was ascertained by determining the calcium and phosphate content, as a basis of the hydroxyapatite structure. The results show that synthetic CP/PLGA nanocomposite alleviate the rehabilitation of weakened alveolar bone. Due to its osteoconductive effect, CP/PLGA can be the material of choice for bone substitution in the future.

Multiple sclerosis (MS) is a consequence of genetic and environmental factors. Geographic, genetic, and biological evidence suggests that an important immunopathogenic factor might be the insufficiency of vitamin D. The aim of our study was to investigate the immunomodulatory effect of alfacalcidol, a vitamin D analogue, on cytokine levels in RRMS patients in relapse. We investigated 15 patients suffering from RRMS relapse (an RRMS group) and two control groups: one control group of healthy subjects (n=10) and a NIND group, consisting of patients with non-inflammatory neurological diseases (n=10). All of the MS patients were treated with 5 ?gr/day of oral alfacalcidol for a period of five days. The serum cytokine levels of TNF-?, IL-10, IL-4, and IL-12 were measured in all the MS patients one day prior to and one day after therapy, and in all the control subjects (ELISA, Quantikine human immunoassay, R&D Systems, UK). Our results showed significantly lower IL- 4 and IL- 12 levels in the RRMS patients group compared to the N group and the NIND group (p

We investigated the importance of two enzymes (superoxide dismutase - SOD and glutathione peroxidase - GSH-Px) in the antioxidant defence of newborns and analysed their activity in: human colostrum and milk (from 63 mothers, after normal delivery, without complications or signs of infection), gastric fluid (from 10 breast-fed newborns, 7-28 days after birth; and from 15 artificially-fed newborns, with no signs of infection, 7-28 days after birth), and plasma (from 10 newborns, 1- 28 days old, with no signs of infection, and 10 newborns, 1-28 days old, with signs of neonatal sepsis). The results of the study showed that there was statistically significant increased activity of SOD (p

The histochemical localisation of two ecto-enzymes, 5′-nucleotidase (5′-NT) and Mg2+-ATPase, was investigated in hyperplastic and recurrent tonsillitis. Detection of enzymes was performed on frozen sections using the classical lead nitrate method. Activity of 5′-NT was demonstrated particularly in the cells of lymphoid follicles and in the basal layer of the surface tonsillar epithelium. There was no difference in localisation of 5′-NT between hyperplastic and recurrent tonsillitis, whereas a stronger reaction in follicular mantle zones was observed in recurrent tonsillitis compared to hyperplastic tonsillitis. Mg2+-ATPase activity was mainly associated with the cells lining the tonsillar crypt, with the interfollicular areas and blood vessels. In recurrent tonsillitis only half of the studied follicular germinal centres expressed Mg2+-ATPase activity, compared to hyperplastic tonsillitis. The similar localisation of 5′-NT and ecto-ATPase in both types of chronic tonsillitis suggests that in inflamed tonsils expression of investigated enzymes probably does not depend on the type of chronic tonsillitis.

Interaction of cultured rat mesangial cells with macrophages induces a marked increase in surface 5′-nucleotidase activity of these mesangial cells. A significant increase in surface 5′-nucleotidase was also observed upon interaction of rat fibroblast with macrophages, both in cocultures and after treatment of fibroblasts with macrophage conditioned medium. Interaction of glomerular epithelial cells in primary culture with macrophages had no effect on surface 5′-nucleotidase activity. No significant effect on enzyme activity was observed after interaction of mesangial - epithelial cells, mesangial cells -fibroblasts, and epithelial cells -fibroblasts.

Hepatocytes are affected by many cytokines and growth factors during liver regeneration. In regenerating rat liver cells cultures, liver cell growth factor (LCGF), hepatic stimulator substance (HSS), interleukin-1 beta (IL-1 beta), as well as their combination, were tested for their ability to activate the enzymes involved in purine metabolism. The enzymes tested were 5' nucleotidase, AMP deaminase, adenosine deaminase and xanthine oxidase. The cytokines alone or in combination, activated 5' nucleotidase and adenosine deaminase. Activity of AMP deaminase was stimulated by IL-1 beta associated with LCGF, HSS and IL-1 beta. Xanthine oxidase was stimulated by IL-1 beta but not with HSS and LCGF. Associated with IL-1 beta these two substances decreased its activity. A novel approach to the understanding of the mechanisms involved in the regulation of purine metabolism during liver regeneration, is proposed.

Introduction. Anti-citrullinated peptides antibodies (ACPA) are present in 80% of sera of rheumatoid arthritis (RA) patients with high specificity for diagnosis and prediction for the development of early erosive arthritis. A few studies have reported a low frequency ACPA in systemic sclerosis (SSc) patients with the presence of arthritis. Objective. The aim of our study was to determine the frequency of ACPA in systemic sclerosis (SSc) patients, their correlation with clinical manifestations and radiographic features. Methods. The study included 82 patients with SSc, mean age 54.4 years, 59 with the limited (lSSc) and 23 with the diffuse (dSSc) form of the disease. The control group included 28 healthy age and sex matched subjects. ACPA and rheumatoid factor (RF) were determined in all SSc patients and healthy subjects in whom standard radiography of hands and wrists was also done. Results. The presence of ACPA was detected in 11 (13.4%) of SSc patients. Their level was not increased in any of the controls. Positive RF was found in 15.9% of SSc patients. Arthritis was present in 17.1%, as well as marginal bone erosions. There was a statistically significant association between positive ACPA and arthritis (p

Indications exist that paramagnetic calcium phosphates may be able to promote regeneration of bone faster than their regular, diamagnetic counterparts. In this study, analyzed was the influence of paramagnetic cobalt-substituted hydroxyapatite nanoparticles on osteoporotic alveolar bone regeneration in rats. Simultaneously, biocompatibility of the material was tested in vitro, on osteoblastic MC3T3-E1 and epithelial Caco-2 cells in culture. The material was shown to be biocompatible and nontoxic when added to epithelial monolayers in vitro, while it caused a substantial decrease in the cell viability as well as deformation of the cytoskeleton and cell morphology when incubated with the osteoblastic cells. In the course of 6 months after the implantation of the material containing different amounts of cobalt, ranging from 5 to 12 wt%, in the osteoporotic alveolar bone of the lower jaw, the following parameters were investigated: histopathological parameters, alkaline phosphatase and alveolar bone density. The best result in terms of osteoporotic bone tissue regeneration was observed for hydroxyapatite nanoparticles with the largest content of cobalt ions. The histological analysis showed a high level of reparatory ability of the nanoparticulate material implanted in the bone defect, paralleled by a corresponding increase in the alveolar bone density. The combined effect of growth factors from autologous plasma admixed to cobalt-substituted hydroxyapatite was furthermore shown to have a crucial effect on the augmented osteoporotic bone regeneration upon the implantation of the biomaterial investigated in this study. This is accepted peer-reviewed version of the article: Ignjatović, N., Ajduković, Z., Savić, V., Najman, S., Mihailović, D., Vasiljević, P., ... & Uskoković, D. (2013). Nanoparticles of cobalt-substituted hydroxyapatite in regeneration of mandibular osteoporotic bones. Journal of Materials Science: Materials in Medicine, 24(2), 343-354. [https://dx.doi.org/10.1007/s10856-012-4793-1] Published version: [https://vinar.vin.bg.ac.rs/handle/123456789/7410]

Although dipyridamole has been extensively studied as an anti-aggregating agent, its mechanism of action has not been elucidated. Cultured mesangial cells were treated with dipyridamole 1-100 microM from 6-72 h. Ecto-5'-nucleotidase activity approximately doubled (from 115 +/- 11 to 226 +/- 14 nmol/min/mg) after treatment with 100 microM dipyridamole for 72 h. This effect was concentration- and time-dependent. Cycloheximide, an inhibitor of protein synthesis, did not alter basal 5'-nucleotidase activity. However, it prevented stimulation by 5 microM dipyridamole. Adenosine availability at the receptor sites was increased by dipyridamole and S-(p-nitrobenzyl)-6-thioinosine (NBTI), which inhibit adenosine uptake into the cell. Addition of dipyridamole or NBTI to the adenosine-treated mesangial cells produced an additive increase in ecto-5'-nucleotidase activity. Dipyridamole, through its effect on extracellular adenosine and ecto-5'-nucleotidase, may have an influence upon regulation of the glomerular microcirculation.

It has been demonstrated in anti-Thy1 glomerulonephritis that extracellular adenine nucleotides have a significant pro-inflammatory activity, however, glomerular ATP/ADPase, which in concert with 5′-nucleotidase converts ATP/ADP, and AMP to anti-inflammatory adenosine had an anti-inflammatory role. We have studied distribution of 5′-nucleotidase and divalent cation-activated ATPase in kidney biopsies of 15 patients with glomerulonephritis. The major finding was an overexpression of 5′-nucleotidase in the mesangium of kidney from patients with membranous nephropathy. No change in 5′-nucleotidase expression was observed in other common forms of glomerulonephritis: IgA nephropathy, mesangioproliferative and mesangiocapillary glomerulonephritis. The distribution of Mg2+-ATPase in investigated specimens was similar to control distribution. Results obtained in this study indicate increased mesangial expression of 5′-nucleotidase in non-proliferative form of glomerulonephritis consistent to a role of mesangial cells in inflammatory processes.

Because A2 adenosine receptor activation stimulates adenylate cyclase and cyclic AMP induces 5'-nucleotidase expression in rat mesangial cells, we examined the effect of adenosine and its analogs on 5'-nucleotidase activity in these cells. A2 adenosine receptors were characterized using [3H]5'-N-ethylcarboxamidoadenosine (NECA) as a tracer. There was a single group of receptor sites with a KD value of 0.53 μM and a number of sites of 1,317 fmol mg . [3H]NECA binding was inhibited preferentially by A2 adenosine analogs and antagonists. Similarly, the order of potency for cAMP stimulation was in favour of A2 adenosine analogs. Rat mesangial cells expressed surface 5'-nucleotidase activity. Exposure of cells for 48 h to adenosine analogs showed that at low concentrations A2 analogs stimulated 5'-nucleotidase activity. These results indicate that adenosine upregulates activity of 5'-nucleotidase, the enzyme responsible for its local formation, via A2 receptor stimulation and increase in cAMP production.

In this article, synthesis and application of calcium phosphate/poly-DL-lactide-co-glycolide (CP/PLGA) composite biomaterial in particulate form, in which each CP granule/particle is coated with PLGA, are described. Two types of the particulate material having different particle sizes were synthesized: one with an average particle diameter between 150 and 250 μm (micron-sized particles, MPs) and the other with an average particle diameter smaller than 50 nm (nanoparticles, NPs). A comparative in vivo analysis was done by reconstructing defects in osteoporotic alveolar bones using both composites. The material, CP granules/particles covered with polymer, was characterized using X-ray structural analysis, scanning electron microscopy, and atomic force microscopy. Changes in reparatory functions of tissues affected by osteoporosis were examined in mice in vivo, using these two kinds of composite materials, with and without autologous plasma. Having defined the target segment, histomorphometric parameters—bone area fraction, area, and mean density—were determined. The best results in the regeneration and recuperation of alveolar bone damaged by osteoporosis were achieved with the implantation of a mixture of nanoparticulate CP/PLGA composite and autologous plasma. After the implantation of microparticulate CP/PLGA, in the form of granules, mixed with autologous plasma, into an artificial defect in alveolar bone, new bone formation was also observed, although its formation rate was slower. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010

Interstitial cells of Cajal (ICC) include several types of specialized cells within the musculature of the gastrointestinal tract (GIT). Some types of ICC act as pacemakers in the GIT musculature, whereas others are implicated in the modulation of enteric neurotransmission. Kit immunohistochemistry reliably identifies the location of these cells and provides information on changes in ICC distribution and density. Human stomach specimens were obtained from 7 embryos and 28 foetuses without gastrointestinal disorders. The specimens were 7–27 weeks of gestational age, and both sexes are represented in the sample. The specimens were exposed to anti-c-kit antibodies to investigate ICC differentiation. Enteric plexuses were immunohistochemically examined by using anti-neuron specific enolase and the differentiation of smooth muscle cells (SMC) was studied with anti-α smooth muscle actin and anti-desmin antibodies. By week 7, c-kit-immunopositive precursors formed a layer in the outer stomach wall around myenteric plexus elements. Between 9 and 11 weeks some of these precursors differentiated into ICC. ICC at the myenteric plexus level differentiated first, followed by those within the muscle layer: between SMC, at the circular and longitudinal layers, and within connective tissue septa enveloping muscle bundles. In the fourth month, all subtypes of c-kit-immunoreactivity ICC which are necessary for the generation of slow waves and their transfer to SMC have been developed. These results may help elucidate the origin of ICC and the aetiology and pathogenesis of stomach motility disorders in neonates and young children that are associated with absence or decreased number of these cells.

Introduction A smear layer forms on the root canal walls as the consequence of root instrumentation. The smear layer formed in such a way considerably influences the quality of root obturation and endodontic treatment outcome. Objective The aim of this study was to ultrastructurally analyze the surface of intracanal dentine after removal of the smear layer by the solution of doxycycline, citric acid and detergent Tween-80 (MTAD). Methods The study involved 60 single-rooted, extracted, human teeth divided into four groups. All samples were instrumented by a step-back technique and manual K-files, and rinsed during instrumentation by 2% CHX and H2O2. The first group of samples was exclusively rinsed by CHX and H2O2; in the second group, besides using CHX and H2O2, MTAD solution was used for the final irrigation. The samples which were rinsed by distilled water (+ control) and the samples rinsed by 5.25% NaOCl and 17% Na EDTA (-control) served as control groups. All samples were observed under the scanning electronic microscope JEOL-JSM-5300. The coronary, middle and apex thirds of the radix region were analyzed. Results The obtained results of the SEM analysis showed that the application of 2% chlorhexidine and hydrogen peroxide did not give clear dentine walls, and the smear layer could not be removed completely. The application of the same combination (CHX and H2O2), added by the final MTAD irrigation solution, led to the efficient removal of the smear layer, while the morphological structure of dentine surface remained unchanged. Statistical analysis showed that canal walls in the experimental group with MTAD as the final irrigation were significantly clearer compared to the control group (p lt 0.001). Conclusion Based on the obtained results, it can be concluded that MTAD is an efficient solution for the final irrigation of the canal system., Uvod Razmazni sloj koji se stvara na zidovima kanala korena zuba posledica je instrumentacije kanala. On značajno utiče na kvalitet opturacije kanala i krajnji ishod endodontskog lečenja. Cilj rada Cilj istraživanja je bio da se ustanovi stepen efikasnosti rastvora doksiciklina, limunske kiseline i deterxenta Tween-80 (poznate pod nazivom MTAD) kao završnog irigansa u uklanjanju razmaznog sloja s površina intrakanalnog dentina. Metode rada Ispitano je 60 jednokorenih ekstrahovanih humanih zuba, podeljenih u četiri grupe. Svi uzorci su instrumentirani tehnikom step-back i ručnim K-turpijama, a tokom instrumentacije ispirani dvoprocentnim hlorheksidinom (CHX) i tropostotnim vodonik-peroksidom (H2O2). Prva grupa uzoraka je ispirana isključivo sa CHX i H2O2, dok je za završnu irigaciju uzoraka druge grupe korišćen i rastvor MTAD. Svi uzorci su posmatrani na skening elektronskom mikroskopu JEOL-JSM-5300. Ultrastrukturno su analizirane koronarna, srednja i apikalna trećina korenske regije. Rezultati Primenom samo CHX i H2O2 kao irigansa ne dobijaju se čisti dentinski zidovi, a razmazni sloj sa zidova nije potpuno uklonjen. Istom kombinacijom irigansa koja je dopunjena rastvorom MTAD za završno ispiranje razmazni sloj se efikasno uklanja, a morfološka struktura dentinske površine se ne menja. Statistička analiza je pokazala da su zidovi kanala uzoraka ispiranih i sa MTAD značajno čistiji nego kod uzoraka kontrolne grupe (p lt 0,001). Zaključak Na osnovu rezultata istraživanja može se zaključiti da je MTAD bio najefikasniji rastvor za završnu irigaciju kanalnog sistema korena zuba.

The ecto-5'-nucleotidase activity of rat glomerular mesangial cells increases after exposure to prostaglandin E2 (PGE2) via cAMP stimulation (Savic et al., 1990, Immunology 70, 321). Therefore we examined whether other cAMP-stimulating agents had a similar effect. Forskolin (1 microM), PGE2 (10 microM), and isoproterenol (10 microM), three products stimulating rat mesangial cell adenylate cyclase activity, enhanced cAMP accumulation within 5 min and 5'-nucleotidase activity after a lag time of at least 24 h, 3-Isobutyl-1-methylxanthine (IBMX) and Ro 20-1724, two drugs inhibiting cAMP degradation, also stimulated cAMP accumulation and 5'-nucleotidase activity. The effects of these agents on 5'-nucleotidase activity were additive with those of the three products stimulating adenylate cyclase activity, except for Ro 20-1724 and forskolin which acted synergistically. Cycloheximide, a blocker of protein synthesis, suppressed the cAMP-dependent increase of 5'-nucleotidase activity. Because ecto-5'-nucleotidase activity is a marker of cell differentiation, the effect of the same cAMP-stimulating agents on cell proliferation was also studied. Forskolin, PGE2, and isoproterenol inhibited [3H]thymidine incorporation into rat mesangial cells in a dose-dependent manner. The same effect was obtained with IBMX (100 microM) and Ro 20-1724 (50 microM). Stimulation of 5'-nucleotidase activity and inhibition of [3H]thymidine incorporation occurred over the same range of concentrations for the various agonists tested. Taken together, these results indicate that expression of ecto-5'-nucleotidase in rat mesangial cells is induced by cAMP whatever the reason for its accumulation. The simultaneous inhibition of DNA synthesis may occur independently or be associated with the stimulation of 5'-nucleotidase expression.

Progression of kidney damage was studied in 18 patients with Balkan endemic nephropathy (BEN), with a mean 15-year follow-up after renal biopsy. According to kidney function, estimated by 99mTc-DTPA clearance, patients were divided into three groups: with apparently normal kidney function (clearance 103.5+/-21.3 mL/min/1.73 m2), with incipient renal failure (clearance 65.5 +/- 11.3), and with advanced renal failure (clearance 28.0+/-6.2). The mean yearly decrease of glomerular filtration rate was 2.74 mL/min. In two patients, an increase of kidney function was recorded. Six patients become dialysis dependent, two from the group with incipient renal failure, but all four from the group with advanced renal failure. Three patients died after 8 to 12 years of follow-up, one from causes unrelated to kidney disease and two from end-stage renal failure. This study has shown that BEN is characterized by a slow course and prolonged evolution, modified by medical supervision and treatment.

The aim of this study is to examine the reparatory ability of the synthetic biomaterial hydroxyapatite-poly-L-lactide (HAp-PLLA), the replacement of alveolar ridge, and rehabilitation of bone defects caused by osteoporosis, in an experimental group of animals. The experiments are performed on syngeneic Sprague Dawley rats. Osteoporosis is induced by glucocorticoids in rats during a 12-week period. After this, the experimental group of animals is divided into five subgroups. An artificial defect is made in the alveolar bone on the left side of the mandible. In one group of animals, the defect is left to heal by itself, while in other groups, pure HAp-PLLA or one mixed with plasma is implanted. The best results are achieved by the implantation of the HAp-PLLA composite biomaterial mixed with autologous plasma. Formation of a new mandibular bone is seen, growing intensely, leading to rapid osteogenesis.

Polyamines were found to modulate the activity of several membrane-bound enzymes, participating in cell growth and differentiation. We have studied the effect of polyamines (spermidine, spermine and putrescine) on rat mesangial cell ectoenzymes: 5′-nucleotidase, Mg2+-ATPase and Ca2+-ATPase. Ecto-5′-nucleotidase activity was significantly increased after 48 h treatment with spermine and spermidine. Mg2+-ATPase was increased only after treatment with spermidine; however, Ca2+-ATPase was significantly increased after both spermine and spermidine treatment of mesangial cells. Culture of mesangial cells with putrescine did not change the activity of these ectoenzymes. Increased expression of mesangial cell ecto-ATPase and ecto-5′-nucleotidase after spermine and spermidine treatment could result in an increased production of adenosine, a powerful autacoid interesting with respect to a role of mesangial cells in inflammatory processes.

Chemically synthesized hydroxyapatite/poly-L-lactide (HAp/PLLA) composite biomaterial was studied in vivo. The biocomposite was implanted into Balb/c Singen mice and after 1 and 3 weeks removed from their organisms and analyzed by the FT-IR spectroscopy. After 1 week of testing in vivo the implanted sample gave a spectrum in which absorption bands arising from newly formed functional groups of amine and peptide can be seen. After 3 weeks, a spectrum with pronounced absorption bands at 3420 and 1650cm-1 assigned to newly generated collagen, a component of the extracellular connective-tissue matrix, was registered. Also, decrease of the intensity absorption band at 1760cm-1 originating from the C=O group of PLLA indicates bioresorption of the PLLA used. Analysis of the microstructure of the sample surface by scanning electron microscopy before and after implantation revealed bioresorption of the PLLA polymer phase and generation of collagen fibers at the sites of implanted bioresorptive PLLA. A mixture of autologous bone powder and HAp/PLLA biocomposite was also examined. After implantation, the same final products as in the case of HAp/PLLA composite biomaterial used alone were found. Copyright © 2001 Elsevier Science Ltd. Chemically synthesized hydroxyapatite/poly-L-lactide (HAp/PLLA) composite biomaterial was studied in vivo. The biocomposite was implanted into Balb/c Singen mice and after 1 and 3 weeks removed from their organisms and analyzed by the FT-IR spectroscopy. After 1 week of testing in vivo the implanted sample gave a spectrum in which absorption bands arising from newly formed functional groups of amine and peptide can be seen. After 3 weeks, a spectrum with pronounced absorption bands at 3420 and 1650cm-1 assigned to newly generated collagen, a component of the extracellular connective-tissue matrix, was registered. Also, decrease of the intensity absorption band at 1760cm-1 originating from the C double bond O group of PLLA indicates bioresorption of the PLLA used. Analysis of the microstructure of the sample surface by scanning electron microscopy before and after implantation revealed bioresorption of the PLLA polymer phase and generation of collagen fibers at the sites of implanted bioresorptive PLLA. A mixture of autologous bone powder and HAp/PLLA biocomposite was also examined. After implantation, the same final products as in the case of HAp/PLLA composite biomaterial used alone were found.

Puromycin aminonucleoside (PAN) nephropathy in rats has been induced by the intraperitoneal injections of PAN. One group of animals which received PAN has been treated simultaneously with captopril (angiotensine converting enzyme-ACE-inhibitor) with the aim to test whether continuing treatment with captopril along with PAN injections would be able to modulate the toxic effects of PAN. The third group of rats was given only captopril. Morphological changes in the kidney were evaluated by scanning electron microscopy that showed the loss of podocyte foot processes in the kidney of PAN treated animals but also in the kidney of captopril treated ones as well as in the animals treated with both drugs simultaneously. Reduced glutathione content, catalase, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), xanthine oxidase activities as well as lipid peroxides were investigated in rat blood and kidney. Captopril given alone produced a significant decrease of plasma lipid peroxides, but it did not show any significant effect on investigated antioxidative factor levels neither in blood nor in the kidney. PAN given alone produced a significant depletion of plasma lipid peroxides, kidney catalase and erythrocyte GSH-Px activity as well as a significant increase of plasma catalase and erythrocyte SOD activity. Treatment of animals with both drugs simultaneously resulted in a significant increase of erythrocyte SOD activity and a significant decrease of plasma lipid peroxides, erythrocyte GSH-Px and kidney SOD activities. Kidney xanthine oxidase activity showed a significant increase in both PAN and PAN plus captopril treated animals in comparison with the values of captopril treated rats. These data suggest that PAN changes the antioxidative factor pattern in rat blood and kidney. Contrary to our expectations that captopril may protect the toxic effects of PAN it only to a certain extent modifies these effects showing protective effect only on tissue catalase activity.

Rhabdomyolysis may account for about 10% of all cases of acute renal failure (ARF). This study was performed to explore the protective influence of proanthocyanidins from seeds of grape in an experimental model of myoglobinuric ARF. Rats were injected with 50% glycerol (8 mL/kg, im) followed immediately and daily in the next three days by ip proanthocyanidins (20 mg/kg) or saline. After 96 h rats were sacrificed and kidney morphology, kidney cortex peptidase activities, and malondialdehyde (MDA) content were determined. A moderate renal failure was produced by glycerol injection with blood urea of 31.8+/-11.0 vs. 7.68+/-0.24 m mol/L, and serum creatinine of 153. +/-38.2 vs. 39.6+/-9.0 micromol/L, in glycerol-induced ARF vs. control rats, respectively. Rats that received proanthocyanidins in addition to glycerol had significantly lower (p0.01) blood urea and serum creatinine levels compared to those receiving glycerol alone. These functional differences between the glycerol and glycerol plus proanthocianidins groups were also confirmed histologically. Kidney cortex dipeptidylpeptidase IV (DPP IV) activity was not significantly changed in glycerol-induced ARF, however, markedly increased after proanthocyanidins treatment. Kidney cortex malondialdehyde content was found significantly increased in glycerol-induced ARF over control level, and was markedly reduced by proanthocyanidin treatment. Taken together, these results provide strong evidence for the protective role of proanthocyanidins from seeds of grape in glycerol-induced ARF. The effect is probably due to the antioxidant activity of proanthocyanidins and to increased expression of kidney cortex DPP IV with effective degradation of TNF-alpha. This may provide therapeutic opportunities of preventing and/or treating myoglobinuric ARF in humans.

Hydroxyapatite/poly-L-lactide (HAp/PLLA) composite biomaterial with PLLA of 50,000 and 430,000 g/mole molecular weight was studied in vivo. The biocomposite with PLLA of both molecular weights was implanted into mice and after 1 and 3 weeks removed from their organisms and analyzed by the FT-IR spectroscopy. After one week of testing in vivo, the implanted samples gave spectra in which absorption bands arising from new-formed functional groups of amine and peptide can be seen. Analysis of the spectra revealed faster formation of peptide compounds when the biocomposite with PLLA of lower molecular weight was used. After 3 weeks, the spectra of the biocomposite of both compositions were registered with pronounced absorption bands at about 3420 and 1650 cm-1 assigned to new-generated collagen, a component of the extracellular connective-tissue matrix. Also, in the case of the biocomposite sample with PLLA of lower molecular weight, disappearance of the previously present absorption band at about 1760 cm-1 originating from the C double bond O group of PLLA indicates complete bioresorption of the PLLA used. Analysis of the microstructures of the sample surfaces by scanning electron microscopy before and after implantation revealed bioresorption of the PLLA polymer phase in the system with PLLA of lower molecular weight and generation of collagen fibers at the sites of implanted bioresorptive PLLA. A mixture of autologous bone powder and HAp/PLLA biocomposite was also examined. After implantation, the same final products as in the case of HAp/PLLA composite biomaterial alone were found. Materials Science Forum, Volume 352

The clinical use of gentamicin is associated by nephrotoxicity in over 10% of patients. However, the biochemical events responsible for proximal tubular injury and acute renal failure (ARF) are still unclear. In the present study, effects of gentamicin and, comparatively, of mercuric chloride upon rat kidney cortex ectopeptidases were studied. Gentamicin was given i.p., 100 mg/kg daily for up to 6 days, mercuric chloride i.p. once 2.5 mg/kg to rats studied after 3 days. Kidney cortex aminopeptidase N decreased significantly after 3 and 6 days' treatment (p0.01), however, angiotensinase A significantly decreased after 3 (p0.01), and much more after 6 days of gentamicin treatment (p0.001). Dipeptidylpeptidase IV activity was significantly decreased only after 6 days of treatment with gentamicin. In mercuric chloride-induced ARF all three peptidase activities were markedly decreased (p0.001). These results suggest that gentamicin-induced decrease in ectopeptidase activities could compromise vasoactive and other biologically active peptides handling, with important consequences upon renal function and metabolism.

Evaluate the effects of flexible tantalum stents (Strecker) implanted into stenotic canine urethras. Eight conditioned, adult, German shepherd dogs, weighing 30–40 kg, were used. Strictures were created surgically in the bulbar urethra just proximal to the os penis. Two months postsurgery, strictures were documented radiographically and then balloon dilated. Following dilatation, a single Strecker stent was placed across the stricture. Stents were 7 mm in expanded diameter and either 2 or 4 cm in length. Retrograde urethrography was performed immediately after stent placement and then biweekly for up to 12 months. Two dogs were sacrificed at 2, 4, 6, and 12 months post-stenting, and necropsy was performed. The urethra was excised, fixed, and examined by scanning electron and light microscopy. Clinical success was achieved without complications in all animals. Hyperplasia of the urothelium was noted 4–6 weeks after stent placement and was most pronounced at 4–6 months. Mucosal folds were found between the stent struts. Restenosis occurred at the distal end of the stent in one dog. Histological alterations were noted in the deeper layers of the urethral wall. Strecker stents were well tolerated in all animals and seem useful for the treatment of urethral strictures.

Because adenosine plays a role in the regulation of glomerular filtration rate and of the release of renin, we examined the possibility of a local source for this mediator. We found that rat cultured glomerular mesangial cells converted 5’-AMP into adenosine. The properties of the enzyme involved in the reaction were those of an ecto-5’nucleotidase: (1) the products of the reaction were generated in the extracellular fluid although no 5’-nucleotidase was released by the cells into the medium; (2) identical activities were found for cultured cells in situ and sonicated cells; (3) the diazonium salt of sulfanilic acid which is a nonpenetrating reagent inhibited up to 75% of the enzyme activity. Ecto-5’-nucleotidase activity of intact cells obeyed Michaelis-Menten kinetics. Apparent Km for 5’-AMP was 0.32 mM. 5’-UMP was a strictly competitive inhibitor. ADP exerted a very powerful inhibitory effect and behaved also as a competitive inhibitor. ATP was inhibitory both by increasing Km and by decreasing Vmax. Ecto-5’-nucleotidase was active in the absence of divalent cations. However, Mg2+, Ca2+, Co2+ and Mn2+ were stimulatory. Zn2+ and Cu2+ suppressed the activity. Concanavalin A, a plant lectin, was markedly inhibitory, suggesting that a glycoprotein moiety was necessary to express enzyme activity. Ecto-5’-nucleotidase activity was not modified during phagocytosis of serum-treated zymosan by mesangial cells. Rat cultured glomerular epithelial cells exhibited a 5’-nucleotidase activity which was 4 times lower than that of the mesangial cells in primary culture. Activity was also present in freshly isolated glomeruli and total cortex, but at lower concentrations than in mesangial cells. These findings suggest that ecto-5’-nucleotidase of mesangial cells may be the main source of adenosine within the glomeruli. Therefore, activity of this enzyme should be essential in the regulation of the glomerular microcirculation.

Macrophages selectively stimulate ecto-5′-nucleotidase activity of cultured mesangial cells. Because rat peritoneal macrophages exhibit a particular binding capacity to rat glomerular mesangial cells in vitro, we have studied the effect of macrophages on two plasma membrane enzymes, ecto-5′-nucleotidase and ecto-Mg 2+ ATPase, of rat cultured mesangial cells. A marked increase of ecto-5′-nucleotidase activity was observed in cocultures of rat mesangial cells and peritoneal macrophages. In addition, macrophage-conditioned medium (MCM) produced a dose-dependent increase of mesangial cell ecto-5′-nucleotidase activity. In contrast, ecto-Mg 2+ ATPase activity was unaffected. The effect of MCM on ecto-5′-nucleotidase activity was apparent after 24 hours and increased with time. Reversion was obtained by MCM withdrawal. Stimulation of ecto-5′-nucleotidase activity by MCM was inhibited by cycloheximide, which suggests that protein synthesis was required. Induction of enzyme activity by MCM depended in part on the presence of extracellular adenosine. The macrophage-released factor responsible for this effect was non-dialysable, heat-stable at 56°C for 30 minutes but heat-inactivated at 100°C for five minutes, inactivated in the presence of trypsin or protease V8, and adsorbed on charcoal. Its apparent molecular weight estimated by gel chromatography was close to 20 kD. MCM from resident macrophages was as potent as MCM from thioglycollate-elicited or zymosan-stimulated macrophages. This stimulatory effect was specific of macrophages since it was absent in the culture medium of rat fibroblasts or mouse thymocytes but present in that of mouse macrophages. These results suggest that peritoneal macrophages synthesize a factor which selectively stimulates ecto-5′-nucleotidase activity of glomerular mesangial cells.

Ni-Ti Shape Memory Alloys (SMAs) have attracted considerable attention as biomaterials for medical devices. However, the biocompatibility of Ni-Ti SMAs is often unsatisfactory due to their poor surface structure. Here we prepared Rapidly Solidifi ed (RS) Ni-Ti SMA ribbons by melt-spinning and their surface was characterised by Augerelectron spectroscopy, X-ray photoelectron spectrometry and scanning electron microscopy. The biocompatibility of the produced ribbons and their immunomodulatory properties were studied on human monocyte-derived dendritic cells (MoDCs). We showed that melt-spinning of Ni-Ti SMAs can form a thin homogenous oxide layer, which improves their corrosion resistance and subsequent toxicity to MoDCs. Ni-Ti RS ribbons stimulated the maturation of MoDCs, as detected by changes in the cells’ morphology and increased expression of HLA-DR, CD86, CD40 and CD83 molecules. However, Ni-Ti RS ribbons enhanced the tolerogenic properties of immature MoDCs, which produced higher levels of IL-10 and IL-27, driving the differentiation of IL-10- and TGF-β-producing CD4 + T cells. On the other hand, in the presence of lipopolysaccharide, an important pro-infl ammatory biomolecule, Ni-Ti RS ribbons enhanced the allostimulatory and Th1 polarising capacity of MoDCs, whereas the production of Th2 and Th17 cytokines was down-regulated. In conclusion, NiTi RS ribbons possess substantial immunomodulatory properties on MoDCs. These fi ndings might be clinically relevant, because implanted Ni-Ti SMA devices can induce both desired and adverse effects on the immune system, depending on the microenvironmental stimuli.