Alojz Ihan
University of Ljubljana
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Featured researches published by Alojz Ihan.
The Journal of Pathology | 1999
Bojan Tepeš; Boris Kavčič; Lijana K. Zaletel; Marija Gubina; Alojz Ihan; Mario Poljak; Igor Križman
In a 2‐ to 4‐year prospective study, the reversibility of gastritis after Helicobacter pylori eradication was analysed. Sixty‐three H. pylori‐positive, chronic duodenal ulcer patients were studied after the successful eradication of bacteria in the period from 1990 to 1993. H. pylori eradication was obtained by triple antimicrobial regimens (colloidal bismuth subcitrate, amoxycillin, and metronidazole) applied for at least 14 days. The criteria for eradication were the absence of bacteria from two antral and two body of stomach biopsies stained with haematoxylin, eosin, and Warthin Starry, and a negative antral biopsy culture. The same diagnostic procedures were repeated, at regular follow‐up endoscopies, each year for up to 4 years. Neutrophil‐granulocyte infiltration of gastric mucosa disappeared in 2 months after bacterial eradication. Mononuclear cellular infiltration was disappearing with statistical significance up to the second year and normal mucosa was observed in the majority of patients in the fourth year of follow‐up. Degeneratively changed lymphoid aggregates were also present in the fourth year in the antrum (12·5 per cent of patients) and in the body of stomach (14 per cent of patients). There was no significant change in antral intestinal metaplasia during the 4 years of follow‐up. Antral atrophy declined significantly in the period from 1 to 3 years of follow‐up. In conclusion, 3–4 years are needed for gastric mucosa to become normal after H. pylori eradication, although some residual lymphoid aggregates persist even after that period. Copyright
Mediators of Inflammation | 2008
Mojca Groselj-Grenc; Alojz Ihan; Metka Derganc
Objective. To evaluate the expression of CD64 and CD163 on neutrophils and monocytes in SIRS with/without sepsis and to compare the diagnostic accuracy of CD64 and CD163 molecules expression determined as (1) mean fluorescence intensities (MFI) of CD64 and CD163; and (2) the ratio (index) of linearized MFI to the fluorescence signal of standardized beads. Patients and methods. Fifty-six critically ill neonates and children with systemic inflammatory response syndrome (SIRS) and suspected sepsis, classified into two groups: SIRS with sepsis (n = 29) and SIRS without sepsis (n = 27). Results. CD64 and CD163 MFI measured on neutrophils and monocytes were elevated in patients with SIRS with sepsis. Diagnostic accuracy of indexes was equal to diagnostic accuracy of MFI for CD64 on neutrophils (0.833 versus 0.854 for day 0 and 0.975 versus 0.983 for day 1) and monocytes (0.811 versus 0.865 for day 0 and 0.825 versus 0.858 for day 1), and CD163 on neutrophils (0.595 versus 0.655 for day 0 and 0.677 versus 0.750 for day 1), but not for CD163 on monocytes. Conclusion. CD64 MFI, CD163 MFI, CD64 indexes for neutrophils and monocytes, and CD163 index for neutrophils can all be used for discrimination of SIRS and sepsis in critically ill neonates and children. CD64 index for neutrophils, however, is superior to all other markers.
Electro- and Magnetobiology | 1998
Maja Ĉemazˆr; TomaZˆ Jarm; Damijan Miklavĉiĉ; Alenka Maĉek Lebar; Alojz Ihan; NataŜA Andreja Kopitar; Gregor Serŝa
Electropermeabilization (electroporation) is a technique widely used to introduce various membrane-impermeable molecules into cells in vitro or in vivo. In this study we determined the effect of different electric-field intensities on electropermeabilization and electrosensitivity of a variety of tumor-cell lines in vitro. For this purpose we used two assays: propidium iodide uptake for measurement of cell electropenneabilization, and the clono-genic or MTT assay for determination of electrosensitivity. Our results showed that electropermeabilization of almost all cell lines tested occurred at 600 V/cm. In contrast, a marked difference in electrosensitivity existed among these cell lines. Our results could be of great importance for pharmacological and biochemical studies in vilro, and for prediction and determination of tumor response in vivo to electropermeabilization combined with chemo-therapeutic drugs (electrochemotherapy) and gene therapy.
Journal of Bacteriology | 2003
Janez Mulec; Zdravko Podlesek; Peter Mrak; Andreja Nataša Kopitar; Alojz Ihan; Darja Zgur-Bertok
In prokaryotes, only a few examples of differential gene expression in cell populations have been described. Colicin production in natural populations of Escherichia coli, while providing a competitive advantage in the natural habitat, also leads to lysis of the toxin-producing cell. Colicin K synthesis has been found to be induced due to an increase in ppGpp (I. Kuhar, J. P. van Putten, D. Zgur-Bertok, W. Gaastra, and B. J. Jordi, Mol. Microbiol. 41:207-216). Using two transcriptional fusions, cka-gfp and cki-gfp, we show that at the single-cell level, the colicin K activity gene cka is expressed in only 3% of the bacterial population upon induction by nutrient starvation. In contrast, the immunity gene cki is expressed in the large majority of the cells. Expression of the cka-gfp fusion in a lexA-defective strain and in a relA spoT mutant strain indicates that differential expression of cka is established primarily at the level of transcription.
Clinical Neurology and Neurosurgery | 2004
Saša Šega; Branka Wraber; Anton Mesec; Alenka Horvat; Alojz Ihan
Abstract Multiple sclerosis is characterized by elevated levels of proinflammatory cytokines produced by Th1 cells and decreased levels of anti-inflammatory cytokines produced by Th2 cells. IFN-β treatment shifts the immune response from the Th1 to Th2 pattern, thus enhancing the production of anti-inflammatory Th2 cytokines such as IL-4, IL-10, and decreasing the production of proinflammatory Th1 cytokines such as IFN-γ. To determine which IFN-β has the stronger immunomodulatory effect we compared the levels of IL-4, IL-10, and IFN-γ of 12 relapsing-remiting MS patients treated with IFN-β1b (Betaferon®) with those of 10 patients treated with IFN-β1a (Avonex®). There were no statistically significant differences in duration of disease, number of relapses before and during treatment, and in EDSS after 2 years of treatment. After 1 year of treatment the concentration of IFN-γ was significantly lower in the Betaferon® group, and concentrations of IL-4 and IL-10 were significantly higher in the Avonex® group. It appears that IFN-β1b has a downregulatory effect on both Th1 and Th2 cytokines, while IFN-β1a causes a shift of the cytokine profile toward the Th2 phenotype. These two IFN have different influences on the pattern of cytokines in MS: IFN-β1a enhances the production of anti-inflammatory cytokines IL-4 and IL-10 and IFN-β1b decreases the production of the proinflammatory cytokine IFN-γ.
Mediators of Inflammation | 2010
Barbara Cvenkel; Andreja Nataša Kopitar; Alojz Ihan
Purpose. To investigate the influence of inflammatory molecules in the aqueous humour and on the ocular surface on the outcome of glaucoma surgery. Methods. Thirty patients who needed antiglaucomatous surgery were included. The interleukin- (IL-) 8, IL-1β, IL-6, IL-10, tumour necrosis factor- (TNF-) α; and IL-12 were determined from aqueous humour preoperatively and the imprints of conjunctiva were analysed for expression of human leukocyte antigen- (HLA-)-DR after surgery by flow cytometry. The success of trabeculectomy was defined as intraocular pressure less than 21 mmHg without antiglaucoma medication. Results. Eyes with trabeculectomy failure at 3 months showed significantly higher TNF-α and IL-6 levels in the aqueous than eyes with successful surgery. Increased expression of HLA-DR on epithelial cells and antigen-presenting cells was not associated with the trabeculectomy outcome. Conclusions. Higher preoperative levels of TNF-α and IL-6 in aqueous humour may contribute to the development of inflammatory milieu and were associated with worse outcome of glaucoma surgery.
Journal of Assisted Reproduction and Genetics | 2012
Branko Zorn; Barbara Golob; Alojz Ihan; Andreja Nataša Kopitar; Mojca Kolbezen
PurposeTo investigate the relationship between sperm apoptotic biomarkers and patient clinical characteristics, conventional sperm parameters and fertility potential.Material and methodsSperm analysis, phospholipid asymmetry, mitochondrial membrane potential (MMP) and DNA denaturation were assessed in 142 males of infertile couples. Seventy-three couples were allocated to the natural conception group, and 55 couples underwent IVF or ICSI.ResultsDNA denaturation correlated positively with age and negatively with testicular volume (TV). MMP correlated negatively with BMI and FSH and positively with TV. Normal viable sperm correlated positively with TV and negatively with age, BMI and FSH. DNA denaturation was associated with a significantly lower natural pregnancy rate (OR 5.4, 95% CI:1.3–22, p = 0.011).ConclusionSperm apoptosis is related to male age, BMI, testicular volume and FSH. Among the apoptotic markers, only DNA denaturation has been found to predict natural pregnancy better than conventional sperm parameters.
Helicobacter | 2012
Alojz Ihan; Irina V. Pinchuk; Ellen J. Beswick
The immune response to Helicobacter pylori is a multifaceted group of mechanisms involving responses that are both protective and damaging to the host. The innate and the adaptive immune responses lead to damaging inflammatory responses, but these responses may fail, allowing for persistence of many infections. Thus, developing new therapeutics and effective vaccines against H. pylori has proven to be arduous. In this manuscript, we will examine the advances in knowledge made in the past year in understanding the host immune response to H. pylori and the progress toward developing a vaccine.
Clinical and Experimental Immunology | 2011
M. Terčelj; Sanja Stopinšek; Alojz Ihan; B. Salobir; Saša Simčič; B. Wraber; Ragnar Rylander
Sarcoidosis is an inflammatory disease. Epidemiological and treatment studies suggest that fungi play a part in the pathogenesis. The aim of this work was to study the effect of fungal cell wall agents (FCWA) on the in vitro secretion of cytokines from peripheral blood monocytes from subjects with sarcoidosis and relate the results to fungal exposure at home and clinical findings. Subjects with sarcoidosis (n = 22) and controls (n = 20) participated. Peripheral blood mononuclear cells were stimulated with soluble or particulate β‐glucan (S‐glucan, P‐glucan), chitin or lipopolysaccharide (LPS), whereafter tumour necrosis factor (TNF)‐α, interleukin (IL)‐6, IL‐10 and IL‐12 were measured. The severity of sarcoidosis was determined using a chest X‐ray‐based score. Serum cytokines (IL‐2R, IL‐6, IL‐10 and IL‐12) were determined. To measure domestic fungal exposure, air in the bedrooms was sampled on filters. N‐acetylhexosaminidase (NAHA) on the filters was measured as a marker of fungal cell biomass. The induced secretion of cytokines was higher from peripheral blood mononuclear cells (PBMC) from subjects with sarcoidosis. P‐glucan was more potent than S‐glucan inducing a secretion. Chitin had a small effect. Among subjects with sarcoidosis there was a significant relation between the spontaneous PBMC production of IL‐6, IL‐10 and IL‐12 and the NAHA levels at home. The P‐glucan induced secretion of IL‐12 was related to the duration of symptoms at the time of diagnosis. Their X‐ray scores were related to an increased secretion of cytokines after stimulation with LPS or P‐glucan. Subjects with sarcoidosis have a higher reactivity to FCWA in vitro and to home exposure. The influence of FCWA on inflammatory cells and their interference with the inflammatory defense mechanisms in terms of cytokine secretion could be important factors for the development of sarcoidosis.
Journal of Pediatric Gastroenterology and Nutrition | 2017
Fabienne Charbit-Henrion; Anja Koren Jeverica; Bernadette Bègue; Gašper Markelj; Marianna Parlato; Simona Lucija Avčin; Isabelle Callebaut; Marc Bras; Mélanie Parisot; Janez Jazbec; Matjaz Homan; Alojz Ihan; Frédéric Rieux-Laucat; Marie-Claude Stolzenberg; Frank M. Ruemmele; Tadej Avcin; Nadine Cerf-Bensussan
Objective: Early-onset inflammatory bowel diseases can result from a wide spectrum of rare mendelian disorders. Early molecular diagnosis is crucial in defining treatment and in improving life expectancy. Herein we aimed at defining the mechanism of an immunodeficiency-polyendrocrinopathy and enteropathy-X-linked (IPEX)–like disease combined with a severe immunodeficiency in 2 siblings born from distantly related parents. Methods: Whole exome sequencing was performed on blood-extracted genomic DNA from the 2 affected children and their parents on the genomic platform of Institut IMAGINE. Candidate gene mutation was identified using the in-house software PolyWeb and confirmed by Sanger sequencing. Protein expression was determined by western blot. Flow cytometry was used to assess consequences of the mutation on lymphocyte phenotype and nuclear factor-kappa B (NF-&kgr;B) activation at diagnosis and after treatment by hematopoietic stem cell transplantation. Results: We identified a homozygous missense mutation in mucosa-associated lymphoid tissue lymphoma translocation 1 gene (MALT1), which precluded protein expression. In keeping with the known function of MALT1, NF-&kgr;B–dependent lymphocyte activation was severely impaired. Moreover, there was a drastic reduction in Forkhead box P3 (FOXP3) regulatory T cells accounting for the IPEX-like phenotype. Following identification of the mutation, both children received hematopoietic stem cell transplantation, which permitted full clinical recovery. Immunological workup at 6 and 12 months after transplantation showed normal NF-&kgr;B activation and correction of regulatory T cells frequency. Conclusions: Along with FOXP3, interleukin 2 receptor alpha chain (IL2RA), and cytotoxic T-lymphocyte protein 4 precursor (CTLA-4) mutations, MALT1 deficiency should now be considered as a possible cause of IPEX-like syndrome associated with immunodeficiency that can be cured by hematopoietic stem cell transplantation.