Showing papers by "University of Rijeka published in 2000"

Temporal pore formation-mediated egress from macrophages and alveolar epithelial cells by Legionella pneumophila.

Abstract: Legionella pneumophila does not induce apoptosis in the protozoan host, but induces pore formation-mediated cytolysis after termination of intracellular replication (L.-Y. Gao and Y. Abu Kwaik, Environ. Microbiol. 2:79–90, 2000). In contrast to this single mode of killing of protozoa, we have recently proposed a biphasic model by which L. pneumophila kills macrophages, in which the first phase is manifested through the induction of apoptosis during early stages of the infection, followed by an independent and temporal induction of necrosis during late stages of intracellular replication. Here we show that, similar to the protozoan host, the induction of necrosis and cytolysis of macrophages by L. pneumophila is mediated by the pore-forming toxin or activity. This activity is temporally and maximally expressed only upon termination of bacterial replication and correlates with cytolysis of macrophages and alveolar epithelial cells in vitro. We have identified five L. pneumophila mutants defective in the pore-forming activity. The phagosomes harboring the mutants do not colocalize with the late endosomal or lysosomal marker Lamp-1, and the mutants replicate intracellularly similar to the parental strain. Interestingly, despite their prolific intracellular replication, the mutants are defective in cytotoxicity and are “trapped” within and fail to lyse and egress from macrophages and alveolar epithelial cells upon termination of intracellular replication. However, the mutants are subsequently released from the host cell, most likely due to apoptotic death of the host cell. Data derived from cytotoxicity assays, confocal laser scanning microscopy, and electron microscopy confirm the defect in the mutants to induce necrosis of macrophages and the failure to egress from the host cell. Importantly, the mutants are completely defective in acute lethality (24 to 48 h) to intratracheally inoculated A/J mice. We conclude that the pore-forming activity of L. pneumophila is not required for phagosomal trafficking or for intracellular replication. This activity is expressed upon termination of bacterial replication and is essential to induce cytolysis of infected macrophages to allow egress of intracellular bacteria. In addition, this activity plays a major role in pulmonary immunopathology in vivo.

Variations of the great arteries in the carotid triangle.

Abstract: The variations of the common carotid artery, as well as of the external and internal carotid arteries, are described. During anatomic dissection on adult cadavers, we investigated the variability of appearance of 40 carotid arterial systems. Special consideration was given to the topographic relations such as the level of the bifurcation of the common carotid artery, the relationship between the external and internal carotid arteries, and the origin of the great collateral branches. Special attention was paid to the origin of the superior thyroid artery. In this article the practical importance of these variations is stressed.

Antibiotic utilization at the university hospital after introducing an antibiotic policy

Abstract: Objective: Antibiotic formulary restrictions are among the most popular methods to control antibiotic utilization in hospitals. The aim of the present survey was to investigate the influence of “reserve antibiotic” on antimicrobial utilization at the University Hospital Center (UHC) Rijeka.

Perception of Current and Ideal Body Size in Preschool Age Children

Abstract: 25 girls and 25 boys between the ages of 5 and 7 years indicated their current and desired body size on Collins' figures. The children's weight and height were measured, and the Body Mass Index was calculated. 52% of girls and 44% of boys expressed a wish to become thinner in relation to perception of their own body. Significant sex differences were found in selection of the ideal figure: girls showed greater preferences for a thinner figure than boys. There was a significant correlation between perception of current figure and Body Mass Index for boys but not for girls.

Plasma cytokine response in mice with bacterial infection.

Abstract: Background: Exposure to microorganisms elicts the production of cytokines. These soluble factors enhance several innate immune functions and regulate the ensuing specific immune response aimed at limiting the spread of infection. Aim: This study was undertaken to quantify the plasma levels of pro-inflammatory cytokines during the course of primary Listeria monocytogenes and Campylobacter jejuni infection. Using an in vivo infection the relationship between endogenous cytokines and the bacterial number in the liver of infected animals was examined. Methods: C57BL/6 mice were infected by the intraperitoneal route. At different time points we determined the number of colony-forming units of bacteria in the liver of infected animals and paralled these with the plasma levels of interferon-gamma (IFN-g ), tumor necrosis factor-alpha (TNF-a ) and interleukin6 (IL-6) measured by enzyme immunoassays. Results: L. monocytogenes infection lasted 10‐11 days. IFN-g production occurred in the early phase but was more pronounced after day 4, following the appearance of specific immunity. The duration of experimental campylobacteriosis was 15 days. Early IFN-g production was not significant but a progressive rise of this cytokine in plasma was seen during the second week post infection. Mice produced measurable amounts of plasma TNF-a immediately after being given viable L. monocytogenes, peaking on day 2‐3 when the greatest number of bacteria was present in the examined organs. During C. jejuni infection plasma TNF-a was produced in a similar manner, but the highest concentrations were found a few days later than in listeriosis, in correlation with the different course of campylobacteriosis. The quantity of IL-6 increased and decreased in concordance with clearance of L. monocytogenes and the clinical status of the animals. C. jejuni did not promote the induction of this cytokine. This is to some extent an unusual finding. With respect to the role of IL-6 in Th2 responses and antibody production, the appearance of this cytokine in campylobacteriosis was more expected. Discussion: During systemic bacterial infection, a network of pro-inflammatory cytokines is activated and blood levels of these cytokines are elevated, albeit inconsistently, with large individual variations and depending on microbial characteristics and structure.

Immune responses and cytokine induction in the development of severe hepatitis during acute infections with murine cytomegalovirus.

Abstract: Salivary gland-derived murine cytomegalovirus (SGV) infections of mice have been widely used as models of human cytomegalovirus infections and in the study of CMV biology Still, many aspects of SGV pathogenesis are not clearly defined Fatal and non-fatal SGV infections were investigated to characterize pathogenetic correlates of mortality and to assess the role of the immune response in disease progression Suppression of immune responses was observed in both lethal and sublethal infections Depletion of immune cell populations in spleen, however, correlated with severe CMV-induced hepatitis and mortality In addition, T cell depletion studies indicated a requirement for this immune cell subset in control of liver damage and survival of infected mice Examination of cytokine responses revealed a previously undescribed shock-like syndrome in lethally-infected mice characterized by high levels of tumor necrosis factor α and interferon γ Furthermore, the sites of tumor necrosis factor α gene induction did not strictly correlate with either viral load or the sites of tissue damage during infection Taken together, these findings define the pathogenetic progression of disease as it relates to disease outcome and suggests that organ-specific differences in cytokine induction play a significant role in the late stages of acute lethal MCMV infections

Work conditions as risk factors for varicose veins of the lower extremities in certain professions of the working population of Rijeka.

Abstract: This research aims to establish the effect of working conditions on the appearance of varicose veins. The epidemiological study was carried out on 1,324 examinees, 530 males and 794 females, employed in 5 highly represented groups of professional activities in Rijeka (catering, trade, light industry, heavy industry and finances). The data were collected by survey and clinical examination. Varicose veins were more prevalent in the trade than in the office workers (odds ratio (OR) = 2.08; 95% confidence interval (CI) = 1.31-3.31), and more prevalent in catering industries than in the office workers (OR = 1.56; 95% CI = 1.001-2.43). chi 2-testing suggested that standing in the workplace (OR = 1.35; 95% CI = 0.95-1.92), weight handling while working (OR = 1.29; 95% CI = 1.01-1.64) and working indoors (OR = 1.61; 95% CI = 1.02-2.53) were risk factors for varicose veins. By multiple logistic regression, the following risk factors were isolated in the total population: female sex (OR = 1.92; 95% CI = 1.37-2.67), workplace (OR = 0.89; 95% CI = 0.78-0.99), age (OR = 1.05; 95% CI = 1.03-1.07), body mass index (OR = 1.04; 95% CI = 1.01-1.07) and family history of the disease (OR = 1.99; 95% CI = 1.55-2.57).

Cytotoxic effect of four root filling materials.

Abstract: The aim of this study was to evaluate the cytotoxic effect of four root canal sealers: AH26, AH Plus, Diaket and Apexit. In the experiment two cell lines, human cervical carcinoma (HeLa) cells and mouse skin fibroblasts (L929), were used. Under aseptic conditions, the sealers were prepared according to the manufacturers' directions, and 0.01 mL of each material was placed in a 24-well plate. The sealers were covered with cell suspension. The cytotoxicity was estimated by determining the number of viable cells by a light microscope, as well as the total number of cells 24 h, 48 h and 120 h after the treatment with mentioned materials. The results obtained in this study showed the high cytotoxcity of the new AH Plus root canal sealer, which was shown to be equally or more toxic to the standard AH26 and Diaket materials. Apexit was the least toxic sealer.

Comparison between Human Cytomegalovirus pUL97 and Murine Cytomegalovirus (MCMV) pM97 Expressed by MCMV and Vaccinia Virus: pM97 Does Not Confer Ganciclovir Sensitivity

Abstract: The UL97 protein (pUL97) of human cytomegalovirus (HCMV) is a protein kinase that also phosphorylates ganciclovir (GCV), but its biological function is not yet clear. The M97 protein (pM97) of mouse cytomegalovirus (MCMV) is the homolog of pUL97. First, we studied the consequences of genetic replacement of M97 by UL97. Using the infectious bacterial plasmid clone of the full-length MCMV genome (M. Wagner, S. Jonjic, U. H. Koszinowski, and M. Messerle, J. Virol. 73:7056-7060, 1999), we replaced the M97 gene with the UL97 gene and constructed an MCMV M97 deletion mutant and a revertant virus. In addition, pUL97 and pM97 were expressed by recombinant vaccinia virus to compare both for known functions. Remarkably, pM97 proved not to be the reason for the GCV sensitivity of MCMV. When expressed by the recombinant MCMV, however, pUL97 was phosphorylated and endowed MCMV with the capacity to phosphorylate GCV, thereby rendering MCMV more susceptible to GCV. We found that deletion of pM97, although it is not essential for MCMV replication, severely affected virus growth. This growth deficit was only partially amended by pUL97 expression. When expressed by recombinant vaccinia viruses, both proteins were phosphorylated and supported phosphorylation of GCV, but pUL97 was about 10 times more effective than pM97. One hint of the functional differences between the proteins was provided by the finding that pUL97 accumulates in the nucleus, whereas pM97 is predominantly located in the cytoplasm of infected cells. In vivo testing revealed that the UL97-MCMV recombinant should allow evaluation of novel antiviral drugs targeted to the UL97 protein of HCMV in mice.

Chromosome studies in patients with defective reproductive success.

Abstract: PROBLEM: The objective of this study was to evaluate the contribution of chromosomal anomalies to decreased fertility in humans. METHOD OF STUDY: In order to investigate the aetiology of infertility in our population and to assess the karyotype in a group of infertile couples and individuals with fertility problems, 782 persons (259 couples, 158 male and 106 female) with different clinical diagnoses of sterility and infertility were analysed cytogenetically. RESULTS: The overall frequency of major chromosomal aberration was 13.1% (103/783), which suggests that fertility or sterility problems in this population are due to chromosomal aberrations. Couples experiencing repeated spontaneous abortions, having malformed children or having sterility problems had chromosomal abnormalities in 18.0% (47/259 couples) of the population studied, and constituted chromosomal disorders occured in couples seeking IVF and ICSI with prevalence of 22.2% (8/38 couples), especially minor mosaicism of sex chromosomes in the female partners. The prevalence of chromosome abnormalities in infertile men was 17.7% (28/158), and in subfertile females, it was 26.4% (28/106). CONCLUSIONS: These results could indicate an increased tendency to miotic sex chromosome non-disjuction in humans.

Binding to and opsonophagocytic activity of O-antigen-specific monoclonal antibodies against encapsulated and nonencapsulated Klebsiella pneumoniae serotype O1 strains.

Abstract: The high mortality of nosocomial infections caused by Klebsiella spp. has acted as a stimulus to develop immunotherapeutic approaches targeted against surface molecules of these bacteria. Since O-antigen-specific antibodies may add to the protective effect of K antisera, we tested the functional and binding capacity of O-antigen-specific monoclonal antibodies (MAbs) raised against different Klebsiella O antigens. The MAbs tested were specific for the O-polysaccharide partial antigens D-galactan II (MAb Ru-O1), D-galactan I (MAb IV/4-5), or core oligosaccharide (MAb V/9-5) of the Klebsiella serogroup O1 antigen. In enzyme-linked immunosorbent assay binding experiments, we found that all MAbs recognized their epitopes on intact capsule-free bacteria; however, binding to encapsulated wild-type strains belonging to different K-antigen serotypes was significantly reduced. The K2 antigen acted as the strongest penetration barrier, while the K7 and K21 antigens allowed some, though diminished, antibody binding. In vitro phagocytic killing experiments showed that MAb Ru-O1 possessed significant opsonizing activity for nonencapsulated O1 serogroup strains and also, to a much lesser extent, for encapsulated strains belonging to the O1:K7 and O1:K21 serotypes. MAbs or antisera specific for the D-galactan II antigen may thus be the most promising agents for further efforts to develop a second-generation Klebsiella hyperimmune globulin comprising both K- and O-antigen specificities.

Muscle fiber type distribution in multifidus muscle in cases of lumbar disc herniation.

Abstract: A study was conducted to analyze the distribution and diameter of muscle fiber types in samples of the medial paravertebral lumbar muscle, i.e., multifidus muscle, obtained from 76 patients who underwent surgery for disc herniation. The samples were compared with 41 control samples of corresponding muscle tissue taken from 41 young healthy subjects who had died a sudden death. Histochemical analysis of fibers associated with myofibrillar adenosine triphosphatase (ATPase) revealed the presence of Type I fibers (slow-twitch fibers) and of Type IIA and IIB fibers (fast-twitch fibers) in both the experimental and control samples. The respective percentage of muscle fibers was calculated and their diameters were measured. Type I fibers predominated in both groups and were significantly larger in diameter than Type IIA and IIB fibers. Both fast-twitch fiber types were distributed in almost equal proportions in the healthy women. In the healthy men, Type IIA fibers prevailed. In the healthy females, the percentage of Type I fibers was found to be slightly higher than in the males, but the diameter of all fiber types was respectively smaller. In the females who had undergone surgery, Type I fibers were significantly larger in diameter than those of the healthy subjects. On the other hand, the diameters of all muscle fiber types were significantly larger, and the percentage of both fast-twitch fibers were Idwer in the samples from men who underwent surgery, as compared to the healthy tissue samples. The morphometric changes in the multifidus muscle at the level of the protruded disc observed by the histochemical method for demonstration of myofibrillar ATPase could not be related to the compressed nerve root in the majority of cases in our study.

Evaluation of craniometric methods for determination of vertical dimension of occlusion.

Abstract: In clinical practice, fully precise method for exact determination of vertical relation of occlusion still does not exist. This study examines the relationship between different craniofacial distances and the distance subnasale-gnathion (Sn-Gn), which represents the lower third of the face in vertical relation determination. The highest coefficient of correlation was (r = 0.8678, p < 0.05) between the distance eye-ear (E-E = lateral border of the ocular orbit-medial opening of the meatus of the external auditory canal) and Sn-Gn. The prediction of the distance Sn-Gn could be determined through the formula: Sn-Gn = E-E/1.08 or through the regression analysis: Sn-Gn = 1.9197 + 0.6449 x E-E. None of the calculated coefficients of correlation was 1, but was < 1, so that the prediction of the distance Sn-Gn by craniometric distances is not absolutely reliable, although it is considerably helpful. Our results point at the variations of craniofacial distances in the Croatian population. Yet, craniometry could still be recommended in everyday clinical practice for prediction of vertical relation of occlusion, as it is a simple, economic and non-invasive method, however in combination with some other methods, which have proved to be helpful.

The Effects of Dispositional and Situational Coping, Perceived Social Support, and Cognitive Appraisal on Immediate Outcome

Abstract: Summary: The effects of coping styles and strategies, perceived social support, and primary and secondary cognitive appraisal on immediate outcome were examined in this study. Two theoretical model...

Assessment of Perforin Expression in Peripheral Blood Lymphocytes in Psoriatic Patients During Exacerbation of Disease

Abstract: There are very few data concerning the role played by cellmediated cytotoxicity, particularly at the molecular level, in the course of psoriasis. Both cytotoxic T lymphocytes (CTL) and natural killer cells contain in their granules the cytolytic protein perforin, a mediator in cell-mediated cytotoxicity reactions. The aim of this study was to analyze perforin expression in various sets and subsets of perforin-positive peripheral blood lymphocytes in 17 patients with chronic psoriasis vulgaris in the exacerbation phase. The results were compared with those of an age- and sex-matched healthy control group (n= 21). Perforin (intracellular antigen) and cell surface antigens were detected using the simultaneous double-staining method. We found a signi®cant increase in perforin (P) expression in the patient group for CTL (CD3+ P+ cells), which are located mostly in the CD8+ population of T lymphocytes (CD8+ P+ ).

Change of sternal perfusion following preparation of the internal thoracic artery--a scintigraphical study.

Abstract: Background: Today the internal thoracic artery (ITA) is the bypass graft of choice due to its superior long-term patency rate. It was the aim of this present prospective study to investigate possible perfusion disturbances and consecutive impaired wound healing induced by the ITA preparation. The sternal perfusion was assessed by bone scintigraphy. Methods: Forty-four patients were included in the study. There were three groups: group I (control, no ITA preparation; n = 12); group II (preparation of the left ITA; n = 21); group III (preparation of both ITAs; n = 11). In all patients a median sternotomy was performed. A bone scintigraphy was performed 4 days before and 12 days after the bypass procedure. Scintigraphical pictures of all patients were assessed visually (one specialized investigator) and the impulse rate was counted by the aid of a computer program. Results: Results of both evaluation methods showed congruently that neither the use of the left nor of both ITAs causes a statistically significant impairment of sternal perfusion. The percentage of postoperative increase of the rate of impulses was in group I: total sternum 55%; right side 56%; left side 55 %. The respective numbers for group II were 58, 63 and 53 %, and for group III 54, 52 and 56%. Surprisingly, perfusion scans in group II revealed an increase in the right sternal half after left ITA preparation. This may be due to the additional blood flow demand of collaterals branching between the right ITA and contralateral intercostal arteries representing a compensatory mechanism of the loss of the left ITA. During the observed postoperative time frame (mean 15 days) no healing disturbance of the sternal wound occurred in any patient. Conclusion: According to the present data the use of one or both ITAs does not cause an increase of healing disturbances, consecutive to a postoperatively decreased sternal blood perfusion.

War wounds to the foot.

Abstract: Thirty-nine patients with foot injuries were admitted to the Clinic for Orthopedic Surgery in Lovran during the war against Croatia. All of them were soldiers wounded by antipersonnel mines. All of the patients were treated using the same protocol. Primary wound care included debridement, necrectomy, and three-dimensional external fixation with or without Kirschner wires. External fixation facilitated postoperative wound care, prevented vicious contracture position, and made fracture healing possible with early weight bearing.

The effect of a compulsory curriculum on ethical attitudes of medical students.

Abstract: The purpose of the present study was to assess the influence of a compulsory curriculum on first-year medical students. The ethical attitude study was performed at the School of Medicine, University of Rijeka, Croatia. The samples consisted of 171 medical students (68 males and 103 females) interviewed at the beginning of the first year of studies. Some of them, namely 143 (56 males and 87 females) were interviewed again at the end of the same academic year. Data were analysed by applying factor analysis under principal component model and varimax criterion as the rotation model. The results clearly show that the current compulsory curriculum without formal ethical education has a limited influence on first-year medical students. That points to the obvious necessity to implement the medical ethics in the course of medical education.

Evaluating the Use of World Wide Web Courseware in Student Teachers’ Education: a Case from Croatia

Abstract: This paper presents the outcome of research that deals with the development and use of World Wide Web hypermedia courseware in student teachers' education in the Department of Information Science at the Faculty of Philosophy, University of Rijeka (Croatia). The purpose of this research is to explore how the use of Web courseware improves the students' learning process as well as their comprehension. The results of a questionnaire about the effectiveness and quality of the courseware and the level of student acceptance of courseware as a teacher resource are presented. The criteria regarding evaluating the effectiveness of the courseware were grouped into five areas: content and instructional design; media elements and aesthetics design; navigation; communication; and evaluation. (Contains 12 references.) (Author/MES) Reproductions supplied by EDRS are the best that can be made from the original document. Evaluating the Use of World Wide Web Courseware in Student Teachers' Education: a Case from Croatia PERMISSION TO REPRODUCE AND DISSEMINATE THIS MATERIAL HAS BEEN GRANTED BY

Immunoprotective Properties of Peptidoglycan Monomer Linked with Zinc in Cholestatic Jaundice

Abstract: Background: Previously it was shown that a new immunostimulator, peptidoglycan monomer linked with zinc (PGM-Zn), might have immunocorrective and hepatotropic effects. Owing to this

The Impact of Traumatic Experience on Attitude Towards Future in Refugee Adolescents

Abstract: Traumatic experience has overall far reaching consequences on personality. In particular, it has significant impact on teenagers that are just approaching the phase of solving their identity problems. This research examines the relation of traumatic experience and attitude towards the future in two groups of adolescents. The first group consists of 20 adolescents-refugees from the East Slavonia that were settled in Rijeka area with their parents during the last six years. The second group consists of 20 adolescent's local inhabitants that were influenced by the war only indirectly. Results show significant difference between refugees and non-refugees in expressed interpersonal trust, frustration tolerance, and formation of close contacts, adaptability, precaution, bitterness, and social desirability. Both groups show increased depression, pessimism and poor self-control. This might be considered as general characteristic of society in war.

Computation and the Three Worlds

Abstract: Discussions about the achievements and limitations of the various approaches to the development of intelligent systems can have an essential impact on empirically based research, and with that also on the future development of computer technologies. However, such discussions are often based on vague concepts and assumptions. In this context, we claim that the proposed `three-world ontology' offers the most appropriate conceptual framework in which the basic problems concerned with cognition and computation can be suitably expressed and discussed, although the solutions of some of these problems seem to lie beyond the horizon of our current understanding. We stress the necessity to differentiate between authentic and functional cognitive abilities; although computation is not a plausible way towards authentic intelligence, we claim that computational systems do offer virtually unlimited possibilities to replicate and surpass human cognitive abilities on the functional level.