Showing papers by "University of Zagreb published in 2000"

Microsatellite variability in grapevine cultivars from different European regions and evaluation of assignment testing to assess the geographic origin of cultivars

Abstract: Nine microsatellite markers (VVMD5, VVMD7, VVS2, ssrVrZAG21, ssrVrZAG47, ssrVrZAG62, ssrVrZAG64, ssrVrZAG79 and ssrVrZAG83) were chosen for the analysis of marker information content, the genetic structure of grapevine cultivar gene pools, and differentiation among grapevines sampled from seven European vine-growing regions (Greece, Croatia, North Italy, Austria and Germany, France, Spain and Portugal). The markers were found to be highly informative in all cultivar groups and therefore constitute a useful set for the genetic characterization of European grapevines. Similar and high levels of genetic variability were detected in all investigated grapevine gene pools. Genetic differentiation among cultivars from different regions was significant, even in the case of adjacent groups such as the Spanish and Portuguese cultivars. No genetic differentiation could be detected between vines with blue and white grapes, indicating that they have undergone the processes of cultivar development jointly. The observed genetic differentiation among vine-growing regions suggested that cultivars could possibly be assigned to their regions of origin according to their genotypes. This might allow one to determine the geographical origin of cultivars with an unknown background. The assignment procedure proved to work for cultivars from the higher differentiated regions, as for example from Austria and Portugal.

Disorders of male rat reproductive tract under the influence of atrazine

Abstract: The effects of atrazine exposure on testicular sperm number, epididymal sperm number and motility and α-glucosidase activity in the epididymis were studied in Fischer rats. Histological changes in the testicular tissue were followed by light and electron microscopy. Groups of adult animals were treated i.p. with 60 and 120 mg atrazine kg−1 body wt. twice a week over 60 days. The results indicate a decrease in the body weight and relative weights of pituitary and ventral prostate vs control, measured on the last day of treatment in both treated groups. Testicular sperm number (expressed as number of sperm per 500 Sertoli cells) in atrazine-treated groups increased with the treatment time due to the reduced sperm motility. Therefore atrazine treatment provoked a significant decrease in sperm number and motility in epididymis, measured after the last day of treatment. α-Glucosidase activity in the epididymis, after the last day of treatment, showed a decrease in both treated groups vs control values. Histological analysis of testicular tissue from treated rats showed the cell disorganization and cell clusters together with spermatocytes. Electron microscopy presented differently vacuolated cytoplasm, collagen fibre was reduced, Leydig cells were of irregular shape with unequal form and cisternae of rough endoplasmic reticulum were accentuated and softly widened. In Sertoli cell cytoplasm, atrazine treatment provoked degenerative changes. According to the results obtained, it is evident that atrazine exerted morphological changes and a toxic effect on sperm and their motility. Copyright © 2000 John Wiley & Sons, Ltd.

The vanishing theorems

Abstract: In general, the computation of higher derived limits lim n X of an inverse system of modules is very difficult. Therefore, most applications of these functors depend on the information whether lim n X vanishes or not. Consequently, it is very important to have conditions, which imply lim n X = 0, as well as conditions, which imply lim n X ≠ O. This section is devoted to both cases.

Bone morphogenetic protein‐7 (osteogenic protein‐1) inhibits smooth muscle cell proliferation and stimulates the expression of markers that are characteristic of SMC phenotype in vitro

Abstract: Vascular proliferative disorders are characterized by migration and proliferation of vascular smooth muscle cells (SMCs), loss of expression of SMC phenotype, and enhanced extracellular matrix synthesis (e.g., type I collagen). We report here that bone morphogenetic protein-7 (BMP-7), a member of the transforming growth factor-beta (TGF-beta) superfamily, is capable of inhibiting both serum-stimulated and growth factor-induced (platelet-derived growth factor [PDGF-BB] and TGF-beta1) cell growth as measured by (3)H-thymidine uptake into DNA synthesis and cell number in primary human aortic smooth muscle (HASM) cell cultures. Concomitantly, addition of BMP-7 stimulates the expression of SMC-specific markers, namely alpha-actin and heavy chain myosin as examined by RT-PCR and Northern blot analyses. The collagen type III/I ratio that becomes lower with the transdifferentiation of SMCs into myofibroblasts is also maintained in BMP-7-treated cultures as compared to untreated controls. Studies on the mechanism of action indicate that BMP-7 treatment inhibits cyclin-dependent kinase 2 (cdk-2) that was stimulated during PDGF-BB-induced proliferation of SMCs and upregulates the expression of the inhibitory Smad, Smad6, which was shown to inhibit TGF-beta superfamily signaling. These results collectively suggest that BMP-7 maintains the expression of vascular SMC phenotype and may prevent vascular proliferative disorders, thus potentially acting as a palliative after damage to the vascular integrity.

Predominant type-2 response in infants with respiratory syncytial virus (RSV) infection demonstrated by cytokine flow cytometry.

Abstract: Acute RSV infection in infancy may produce some asthma-like symptoms and may be followed by a recurrent wheeze later in childhood. It has been proposed that RSV infection stimulates type-2 cytokine responses, resembling those found in atopy and asthma. Peripheral blood cells were obtained from RSV-infected infants (n = 30) and healthy controls (n = 10). After in vitro restimulation of the cells, intracellular IL-4 and interferon-gamma (IFN-γ) were measured by flow cytometry. The cells from RSV-infected infants produced more IL-4 and less IFN-γ than those from healthy controls. IL-4 production was more frequent in CD8 than in CD4 cells, and the bias toward IL-4 production was greatest in infants with mild infections, whereas IFN-γ production increased with disease severity. Our conclusions are that RSV infection is associated with IL-4 production in peripheral T cells, and that peripheral blood in infants with severe disease may be depleted of cytokine-producing cells.

Detection of micronuclei in haemocytes of zebra mussel and great ramshorn snail exposed to pentachlorophenol

Abstract: The frequency of micronuclei (MN) induced by pentachlorophenol (PCP) in haemocytes of zebra mussel, Dreissena polymorpha Pall. and great ramshorn snail, Planorbarius corneus L. was determined over a 14 days of exposure (sampling after 4, 7 and 14 days) under laboratory conditions. PCP doses for zebra mussel ranged from 10 to 150 μg/l, and for ramshorn snail from 10 to 450 μg/l. Micronuclei were detected after bisbenzimide fluorescent staining. Positive responses were observed in both species. The mean MN frequencies in treated mussels ranged between 0.69 and 7.50‰, and between 2.07 and 13.80‰ in treated snails. The spontaneous MN levels in mussels averaged from 0.5 to 2.75‰, and in snails from 1.56 to 2.00‰. Our results suggest that haemolymph of both species represent an appropriate test tissue in environmental genotoxicity assessment.

Synthesis of tungsten trioxide hydrates and their structural properties

Abstract: Tungsten trioxide hydrates were synthesized by (a) cation exchange reaction from sodium tungstate solution and (b) precipitation from sodium tungstate solution by the addition of HCl solution. The samples were analyzed by XRD, DTA/TGA, Raman and FT-IR spectroscopy. XRD showed formation of WO 3 ·H 2 O by cation exchange reaction, whereas WO 3 ·0.33H 2 O was identified by XRD as a product of the acidification of sodium tungstate solution with HCl solution. After heating at 320°C, WO 3 ·H 2 O transformed into WO 3 , whereas the WO 3 ·0.33H 2 O crystal structure remained and these results were in agreement with DTA/TGA measurements. The WO 3 ·H 2 O sample synthesized by cation exchange reaction showed a weight loss corresponding to one molecule of water in the crystal structure. However, samples WO 3 ·0.33H 2 O showed a much greater weight loss upon heating than could be expected on the basis of the WO 3 0.33H 2 O formula. The phase transition WO 3 ·H 2 O→WO 3 was also monitored by Raman and FT-IR spectroscopy. In the case of WO 3 ·0.33H 2 O samples, the basic features of Raman and FT-IR spectra did not change on heating to 320°C, thus indicating that the heating of WO 3 ·0.33H 2 O up to this temperature did not destroy the original crystal structure. Contrary to this, after heating the WO 3 ·H 2 O sample to 320°C, the Raman and FT-IR spectra showed a series of new bands caused by the phase transition WO 3 ·H 2 O→WO 3 .

Absolute proton affinity of some polyguanides

Abstract: The problem of the absolute proton affinity (APA) of some polyguanides is addressed by the MP2(fc)/6-311+G//HF/6-31G theoretical model. It is shown that the linear chain polyguanides exhibit increased basicity as a function of the number of guanide subunits. However, the saturation effect yields an asymptotic APA value of 254 kcal/mol. Branched polyguanides on the other hand have higher APAs than their linear counterparts. The largest proton affinity is found in a doubly bifurcated heptaguanide, being as high as 285 kcal/mol, thus potentially representing one of the strongest organic bases. Finally, it is found that all polyguanides protonate at imino nitrogen atoms, since they are apparently susceptible the most to the proton attack. The origin of their very high intrinsic basicity is traced down to a dramatic increase in the resonance interaction of the corresponding conjugate bases. For instance, the increase in the resonance energy in the protonated guanidine is estimated to be in a range of 24-27 kcal/mol, which is higher than the aromatic stabilization in benzene. The proton affinity of some polycyclic guanides including Schwesinger proton sponge and porphine is briefly discussed.

Metronidazole in the Treatment of Chronic Radiation Proctitis: Clinical Trial

Abstract: Aim To evaluate the effectiveness of metronidazole in combination with corticosteroids in enema and mesalazine (5-aminosalicylic acid) in comparison with the same protocol without metronidazole in the treatment of chronic radiation proctitis. Methods Sixty patients with rectal bleeding and diarrhea were randomly divided into two groups. Patients in the first group were treated with metronidazole (3x400 mg orally per day), mesalazine (3x1 g orally per day), and betamethasone enema (once a day during 4 weeks). Patients in the second group were treated with mesalazine and betamethasone enema, but without metronidazole. The efficacy of metronidazole was assessed on the basis of rectal bleeding, diarrhea, and rectosigmoidoscopy findings in all patients. Results The incidence of rectal bleeding and mucosal ulcers was significantly lower in the metronidazole group, 4 weeks (p=0.009), 3 months (p=0.031), and 12 months (p=0.029) after therapy. There was also a significant decrease in diarrhea and edema in the metronidazole group, 4 weeks (p=0.044), 3 months (p=0.045), and 12 months (p=0.034) after treatment. Conclusion Metronidazole in combination with mesalazine and betamethasone enemas successfully treats rectal bleeding and diarrhea in chronic radiation proctitis.

Depletion of CD4 and CD8 T Lymphocytes in Mice In Vivo Enhances 1,25-Dihydroxyvitamin D3-Stimulated Osteoclast-Like Cell Formation In Vitro by a Mechanism That Is Dependent on Prostaglandin Synthesis

Abstract: To investigate the role of T lymphocytes in osteoclastogenesis, we performed in vivo depletion of CD4 and/or CD8 T lymphocyte subsets and evaluated in vitro osteoclast-like cell (OCL) formation. T lymphocyte depletion (TLD) with mAbs was confirmed 24 h later by flow cytometry. OCL formation was stimulated with 1, 25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)) in bone marrow and with recombinant mouse (rm) receptor activator of NF-kappaB ligand (RANK-L) and rmM-CSF in bone marrow and spleen cell cultures. OCL formation was up to 2-fold greater in 1,25-(OH)(2)D(3)-stimulated bone marrow cultures from TLD mice than in those from intact mice. In contrast, TLD did not alter OCL formation in bone marrow or spleen cell cultures that were stimulated with rmRANK-L and rmM-CSF. The effects of TLD seemed to be mediated by enhanced PG synthesis, because the PGE(2) concentration in the medium of 1, 25-(OH)(2)D(3)-stimulated bone marrow cultures from TLD mice was 5-fold higher than that in cultures from intact mice, and indomethacin treatment abolished the stimulatory effect of TLD on OCL formation. There was a 2-fold increase in RANK-L expression and an almost complete suppression of osteoprotegerin expression in 1, 25-(OH)(2)D(3)-stimulated bone marrow cultures from TLD mice compared with those from intact mice. Although there was a small (20%) increase in IL-1alpha expression in 1, 25-(OH)(2)D(3)-stimulated bone marrow cultures from TLD mice, TLD in mice lacking type I IL-1R and wild-type mice produced similar effects on OCL formation. Our data demonstrate that TLD up-regulates OCL formation in vitro by increasing PG production, which, in turn, produces reciprocal changes in RANK-L and osteoprotegerin expression. These results suggest that T lymphocytes influence osteoclastogenesis by altering bone marrow stromal cell function.

Lepton flavor violation in the standard model extended by heavy singlet Dirac neutrinos

Abstract: Low energy neutrinoless lepton flavor violating (LFV) processes are studied in an extension of the Standard Model (SM) by heavy SU(2)xU(1) singlet Dirac neutrinos. An upper bound procedure is elaborated for the evaluation of amplitudes. A comment on the extraction of heavy neutrino mixings from astrophysical observations is given. For processes not treated in the applied model the formalism not treated in the applied model the formalism for evaluating the branching ratios (BRs) is presented. The processes previously studied in the model are carefully examined. Some of the previous results are improved. Special attention is paid to the structure of the amplitudes and BRs as well as to the relations between BRs of different LFV processes. Numerical analysis of the BRs is done. The decoupling of heavy neutrinos is discussed and it is explicitely shown that the very heavy neutrinos decouple when the upper bound procedure is applied. The upper limits of the BRs are compared with the current experimental upper bounds and the processes interesting for the search for LFV are proposed. The LFV decays are shown to be unsuitable for finding upper bounds on "diagonal" LFV parameters. The B-meson LFV processes are suggested for the search of LFV in future B-factories.

Copper corrosion at various pH values with and without the inhibitor

Abstract: The inhibitory action of BTAH on copper was investigated in 1 M sodium acetate solution in the pH range 4–10, using cyclic voltammetry and impedance spectroscopy. Cyclic voltammetry showed that the rearrangement of the surface oxide layer in the presence of BTAH is very fast in slightly alkaline solutions, while it is time- and concentration-dependent in neutral and slightly acidic solutions. The adsorption behaviour of BTAH on the electrode surface at c(BTAH) ≤ 0.5 mM followed a Flory–Huggins adsorption isotherm with ΔG∘ ranging from −30.0 to −39.0 kJ mol−1, depending on the pH. Impedance spectra were characterized by two time constants relating to the charge transfer and transport of copper ions through the oxide layer, the latter being the rate determining step. These enabled the determination of important properties of the adsorbed layer and the passivated film. The results indicate that the surface layer is of dielectric nature, and its protection increases with increasing inhibitor concentration and solution pH. The finite diffusion impedance was analysed using a diffusion factor B, and the values of the diffusion coefficient and concentration of copper species in the film were estimated.

Three-dimensional ultrasonographic and power Doppler characterization of ovarian lesions.

Abstract: Objective To determine whether three-dimensional ultrasound (3D US) and 3D power Doppler can improve the ability to differentiate benign from malignant ovarian lesions Methods Transvaginal ultrasound, transvaginal color Doppler, 3D US and 3D power Doppler were performed on 90 patients with ovarian lesions during the week prior to surgery Four independent sonographers were blinded to the results of other ultrasound studies Results Color Doppler studies added to transvaginal gray-scale characterization of ovarian lesions resulted in sensitivity of 8889% and specificity of 9753% in diagnosing ovarian malignancy Qualitative analysis of tumor vascularity by 3D power Doppler added to morphological features obtained by 3D US is clinical pertinent and reached sensitivity and specificity of 100 and 9876%, respectively Conclusion Three-dimensional ultrasound and power Doppler can enhance and facilitate the morphologic and functional evaluation of both benign and malignant ovarian lesions Introduction of the 3D quantitative technique for measurements of blood flow and vascularization may increase clinical relevance of these studies Copyright © 2000 International Society of Ultrasound in Obstetrics and Gynecology

Schiff Bases Derived from Aminopyridines as Spectrofluorimetric Analytical Reagents

Abstract: Fluorescence characteristics of Schiff bases derived from aminopyridines and salicylaldehyde were studied and possibilities of their analytical application were discussed. It is shown that these compounds can be used for spectrofluorimetric monitoring of small pH changes as well as for sensitive metal ion determinations. As an illustration of metal ion determination, a spectrofluorimetric procedure for analysis of Cu2+ is presented. Determination of Cu2+ was based on the quenching effect of Cu2+ on the fluorescence of N, N'-bis(salicylidene)-2, 3-pyridinediamine in dioxan/water 1/1 (volume fraction of dioxan, phi = 50%). Under optimal conditions (pH = 8.9, lambda(ex) = 340 nm, lambda(em) = 385 nm, c(ligand) = 1.0 x 10(-5) M), the linearity range of the calibration curve was 30-350 mu g L-1 Cu2+. The procedure is fast, simple and reproducible. It is characterized by high sensitivity and satisfactory selectivity. An additional advantage of Schiff bases derived from aminopyridines as analytical reagents lies in the simplicity of preparation procedures, enabling improvement of the determination methods not only by optimization of experimental conditions, but also by designing suitable structural characteristics of the reagent.

Complex structural pattern of the Alpine-Dinaridic-Pannonian triple junction

Abstract: Due to the political boundaries between the Central European countries, on one hand, and the thick Tertiary cover in the Pannonian Basin, on the other, the eastward continuation of the Alpine and Dinaridic units has been ambiguous and poorly documented. Based on comparative analyses, the aim of the present paper is to define the pre-Tertiary structural units in the junction area of the Alpine, Dinaridic, and Pannonian regions, in the SW part of the Pannonian Basin, and to draw conclusions on the continuation of the Alpine and Dinaridic units. According to diagnostic characteristics of the Periadriatic Lineament system, the Balaton Lineament system may be considered as its direct eastern continuation. North of the Periadriatic–Balaton Lineament system, the Transdanubian Range Unit, due to its pre-Tertiary paleogeographic setting, shows mainly South Alpine facies relations; however, its present structural position is identical to that of the Upper Austroalpine nappes. Between the Periadriatic–Balaton and Zagreb–Zemplin Lineament systems heterogeneous structural units are juxtaposed, forming the Sava Composite Unit. In the northern part of this composite unit non-metamorphosed nappes occur which can be considered the eastern continuation of the South Alpine units. These nappes are overthrust onto Internal Dinaridic units in the Tertiary. The Zagreb–Zemplin (Mid-Hungarian) Lineament separates the Sava Unit from the Tisza Unit showing close affinity to the Tethyan margin of the Eurasian plate during the early stage of the Alpine evolution.

Improvement and further generalization of inequalities of Ostrowski-Grüss type

Abstract: We improve some inequalities of Ostrowski-Gruss type and further generalize them. We apply the obtained results to the estimation of error bounds for some numerical quadrature rules. Also, some bounds for the differences of some special means are discussed.

Study on the Implementation of Optical Transparent Transport Networks in the European Environment—Results of the Research Project COST 239

Abstract: This paper reports the main results obtained in the framework of the COST239 project on the implementation of transparent optical network schemes to connect main European cities. The investigation on transmission limitations has shown that transmission systems, for which 1662:5 Gbit/s WDM systems are used due to traf®c reasons, have a maximum range shorter than 1000 km. This condition does not allow a completely transparent network. Two solutions, the partitioned and the gridconnected network architecture, are proposed, described, and compared in the paper.