Publications by authors named "Maja Santak"

Negative-stranded RNA viruses (NSVs) are important human pathogens, including emerging and reemerging viruses that cause respiratory, hemorrhagic and other severe illnesses. Vaccine design traditionally relies on the viral surface glycoproteins. However, surface glycoproteins rarely elicit effective long-term immunity due to high variability.

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Recombinant mumps viruses (MuVs) based on established vaccine strains represent attractive vector candidates as they have known track records for high efficacy and the viral genome does not integrate in the host cells. We developed a rescue system based on the consensus sequence of the L-Zagreb vaccine and generated seven different recombinant MuVs by (a) insertion of one or two additional transcription units (ATUs), (b) lengthening of a noncoding region to the extent that the longest noncoding region in MuV genome is created, or (c) replacement of original L-Zagreb sequences with sequences rich in CG and AT dinucleotides. All viruses were successfully rescued and faithfully matched sequences of input plasmids.

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Inactivated and live attenuated vaccines have improved human life and significantly reduced morbidity and mortality of several human infectious diseases. However, these vaccines have faults, such as reactivity or suboptimal efficacy and expensive and time-consuming development and production. Additionally, despite the enormous efforts to develop vaccines against some infectious diseases, the traditional technologies have not been successful in achieving this.

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Article Synopsis
  • - The study focuses on the prevalence of drug resistance to NS5A inhibitors in patients with genotype 1 Hepatitis C virus (HCV) in Croatia, noting that current treatment relies on direct-acting antivirals targeting specific viral proteins.
  • - Researchers found that 14.3% of patients had resistance-associated substitutions (RAS), with a notable difference between subtypes: 24.2% in subtype 1b and 7.8% in subtype 1a.
  • - Three specific mutations linked to drug resistance were identified, along with two that lower susceptibility to treatment, indicating a relatively homogenous viral population and highlighting the need for local resistance pattern evaluations for better clinical outcomes.
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Although human rubulavirus 2 (HPIV2) is an important respiratory pathogen, little is known about its molecular epidemiology. We performed a comparative analysis of the full-length genomes of fourteen HPIV2 isolates belonging to different genotypes. Additionally, evolutionary analyses (phylogenetic reconstruction, sequence identity, detection of recombination and adaptive evolution) were conducted.

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Article Synopsis
  • * Researchers analyzed M protein sequences from various human parainfluenza viruses and respiratory viruses, finding that while HPIV M proteins varied widely, they were more stable within other viruses.
  • * Notably, an 8-nucleotide insertion was identified in one HMPV M gene sequence, suggesting the need for further investigation, especially regarding HPIV2 M proteins that haven't been extensively studied.
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Background: The canonical genome organization of measles virus (MV) is characterized by total size of 15 894 nucleotides (nts) and defined length of every genomic region, both coding and non-coding. Only rarely have reports of strains possessing non-canonical genomic properties (possessing indels, with or without the change of total genome length) been published. The observed mutations are mutually compensatory in a sense that the total genome length remains polyhexameric.

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O1 HIV-1 diversity in Bulgaria (current molecular epidemiological picture) Ivailo Alexiev, Reneta Dimitrova, Anna Gancheva, Asya Kostadinova, Mariyana Stoycheva, Daniela Nikolova, Ivaylo Elenkov O2 Knowledge, attitudes and practices of the general population on HIV/AIDS, hepatitis B and C in Romania Cătălin Tilișcan, Mioara Predescu, Bogdan Păunescu, Anca Streinu-Cercel, Oana Săndulescu, Claudiu Mihai Șchiopu, Mădălina Hristache, Lăcrămioara Aurelia Brîndușe, Adrian Streinu-Cercel O3 The prevalence of human leukocyte antigen-B*57:01 allele carriers and CXCR4 tropism among newly diagnosed HIV infected patients in Serbia Marija Todorovic, Marina Siljic, Dubravka Salemovic, Valentina Nikolic, Ivana Pesic-Pavlovic, Jovan Ranin, Djordje Jevtovic, Maja Stanojevic O4 HIV transmission among stable serodiscordant couples from the former Pediatric Cohort follow up in the National Institute of Infectious Diseases Ana Maria Tudor, Delia Vlad, Mariana Mărdărescu, Sorin Petrea, Cristina Petre, Ruxandra Neagu-Drăghicenoiu, Rodica Ungurianu, Alina Cibea, Odette Chirilă, Cristian Anghelina, Ileana Coserea O5 Unemployment is associated with syringe sharing among people who inject drugs in Greece Pantelia-Amalia Krikelli, Eirini Pavlitina, Mina Psichogiou, Demetris Lamnisos, Leslie Williams, Anya Korobchuk, Britt Skaathun, Pavlo Smyrnov, John Schneider, Vana Sypsa, Dimitrios Paraskevis, Angelos Hatzakis, Samuel R. Friedman, Georgios K. Nikolopoulos O6 Correlation of adipocytokine levels in different types of lipodystrophy in HIV/AIDS patients Gordana Dragović, Danica Srdić, Al Musalhi Khawla, Ivan Soldatović, Jelena Nikolić, Djordje Jevtović, Devaki Nair O7 IP10 – a possible biomarker for the progression of HIV infection Aura Temereanca, Adelina Rosca, Luminita Ene, Benchawa Soontornniyomkij, Carmen Diaconu, Claudia Dita, Cristian Achim, Simona Ruta O8 A permanent challenge: persistent low viremia in HIV positive patients on ART Șerban Benea, Ruxandra Moroti, Raluca Jipa, Eliza Manea, Andrada Stan, Elisabeta Benea, Dan Oțelea, Adriana Hristea O9 Infections in IDUs according to their HIV status Adriana Hristea, Irina Lăpădat, Raluca Jipa, Ruxandra Moroti, Șerban Benea, Doina Antonică, Irina Panait, Roxana Petre O10 Trends in combined antiretroviral therapy used in methadone program integrated with HIV care - 20 years of experience Justyna D.

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The dynamics and evolution of the human parainfluenza virus type 2 (HPIV2) in Croatia, and also globally, are largely unknown. Most HPIV2 infections are treated symptomatically outside the hospital setting. Thus, the diagnosis is missing making it difficult to follow the genetic variation and evolution of the HPIV2.

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Background: Mumps virus is a negative-sense, single stranded RNA virus consisting of a ribonucleocapsid core enveloped by a lipid membrane derived from host cell, which causes mumps disease preventable by vaccination. Since virus lipid envelope and glycosylation pattern are not encoded by the virus but dependent on the host cell at least to some extent, the aim of this work was to analyse L-Zagreb (L-Zg) mumps virus lipids and proteins derived from two cell types; Vero and chicken embryo fibroblasts (CEF). Jeryl Lynn 5 (JL5) mumps strain lipids were also analysed.

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L-Glutamine (L-Gln) instability in liquid media is a well-known fact. Also, negative effect of ammonia, one of the L-Gln degradation products, on viability of many cell cultures and on replication of different viruses has been described. However, negative effects of ammonia have been reported in doses excessively exceeding those that could be generated in regularly used liquid culture media due to spontaneous L-Gln breakdown (below 2 mM).

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In spite of the success of the mumps vaccination, recent mumps outbreaks have been reported even among individuals with a history of mumps vaccination. For a better understanding of why the vaccination failed in cases of vaccinees who fell ill during recent mumps outbreaks, the immunological events during infection and/or vaccination should be better defined. In the work presented here we sought to identify new neutralization sites on the mumps virus surface glycoproteins.

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Immunization programs have implemented live attenuated mumps vaccines which reduced mumps incidence ≥97%. Some of the vaccine strains were abandoned due to unwanted side effects and the genetic marker of attenuation has not been identified so far. Our hypothesis was that non-infectious viral particles, in particular defective interfering particles (DIPs), contribute to neuroattenuation.

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Human type I interferons (IFNs) comprise one IFN-β, -ω, -κ, and -ɛ and 12 different IFN-α subtypes, which play an important role in early host antiviral response. Despite their high structural homology and signaling through the same receptor, IFN-α subtypes exhibit different antiviral, antiproliferative, and immunomodulatory activities. Differences in the production of IFN-α subtypes therefore determine the quality of an antiviral response.

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Background: In the present work, we compared the antitumor effects of native human interferon-α (IFN-α) (nHuIFN-α) and recombinant human IFN-α (rHuIFN-α) on human lung adenocarcinoma A549 cells.

Materials And Methods: The antitumor activity was determined by measuring cell viability and apoptosis, while the abundance of mRNA, measured by polymerase chain reaction (PCR), determined the potential role of p21 and survivin in antitumor activity of nHuIFN-α.

Results: The results show that nHuIFN-α significantly reduced A549 cell viability, compared to rHuIFN-α.

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Measles virus (MV) strains derived from patients with subacute sclerosing panencephalitis (SSPE), SSPE strains, possess numerous mutations when compared to viruses belonging to the same genotype and circulating in similar time period. Although many SSPE strains have been extensively characterized, none of them belongs to D4 genotype which currently predominates in Europe where it has caused a number of recent outbreaks/epidemics. We sequenced an MV derived from a patient with long-term SSPE; the virus was named MVs/Zagreb.

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Live attenuated vaccines against mumps virus (MuV) have been traditionally produced by passaging the virus in the embryonated chicken eggs or primary chicken embryo fibroblasts (CEFs). Virus propagation on these cell substrates enables successful virus attenuation and retains it sufficiently antigenic to induce lasting protective immunity in humans. The aim of this study was to identify critical factors for MuV replication in primary CEFs grown on a small-scale level in order to explore possibilities for improvements in the virus replication and yield.

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Arsenal of pattern-recognition receptors alongside antibody production machinery make B cells vulnerable to autoimmune response if an autoantigen elicits both pathways in a self-sustained fashion. Systemic lupus erythematosus is an autoimmune disease characterized by autoantibodies to DNA, RNA and related structures. Murine studies demonstrated autoreactive B cell activation upon TLR9 stimulation with DNA-containing immune complexes.

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Background: Physicochemical characteristics of liposome/DNA complexes influence transfection efficiency and affect each other in a very intricate way. The result of this is discrepancies in conclusions drawn about the individual influence of each one.

Methods: Aiming to elucidate the influence of liposome/DNA charge ratio and size on transfection efficiency and on each other, we used liposome/DNA complexes with charge ratio (+/-) in the range of 1-50 and extruded through membranes of 400, 200, and 100 nm.

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RNA viruses display the highest replication error rate in our biosphere, leading to highly diverse viral populations termed quasispecies. The gold standard method for detection and quantification of variants in a quasispecies is cloning and sequencing, but it is expensive, laborious and time consuming. Therefore, other mutation detection approaches, including SSCP, are often used.

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The production of economically acceptable viral vaccines of high quality requires simple and efficient methods for purification and concentration of viral particles. Ion-exchange chromatography (IEC) has become one of commonly used methods for large-scale downstream purification of viruses. Viruses possess different biological and/or biochemical properties and therefore IEC conditions must be established specifically for each virus.

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During July 2009 an outbreak in neonates represented with gastrointestinal and respiratory symptoms was observed at the Neonatal Postintensive Care Unit, Clinical Hospital Center, Zagreb. Human parechovirus type 1 (HPeV1) was isolated from seven patients, one of whom was asymptomatic. All but one were premature neonates with serious underlying conditions, and all recovered fully after several days.

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Background: Commercial preparations of native human interferon alpha (nHuIFN-alpha) contain several subtypes of interferon-alpha (IFN-alpha) and traces of other cytokines. Recently, we described its antifibrotic potential and showed nHuIFN-alpha to have a greater effect than that of recombinant human IFN-alpha (rHuIFN-alpha). We hypothesized that cooperation between different cytokines in the nHuIFN-alpha preparation is essential for this effect.

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The two most commonly used methods for the determination of a virus potency are plaque assay and 50% cell culture infective dose (CCID(50)) assay, both based on cytopathic effect observation. We compared the potency estimates obtained by plaque and CCID(50) assays for nine mumps virus strains that produce different cytopathic effects in Vero cells. The ratios of CCID(50) and plaque assay quantification results differed for different strains and were in a range of 0.

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Human plasma is an important medical substance and a raw material for production of various therapeutics. During blood sampling, storage and processing, genomic DNA is released into plasma from nucleated blood cells that are damaged in the course of the procedure. In order to determine the concentration of contaminating DNA in plasma, we developed a method for DNA isolation by using anion-exchange chromatography on a BIA Separations CIM (convective interaction media) diethylaminoethyl column.

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