Head and Neck Cancer Patients' Survival According to HPV Status, miRNA Profiling, and Tumour Features-A Cohort Study.

Head and neck cancers (HNC) are a heterogeneous group of tumours mainly associated with tobacco and alcohol use and human papillomavirus (HPV). Over 90% of all HNC are squamous cell carcinomas (HNSCC). Sample material from patients diagnosed with primary HNSCC (n = 76) treated with surgery as primary treatment at a single centre were assessed for HPV genotype, miR-9-5p, miR-21-3p, miR-29a-3p and miR-100-5p expression levels. Clinical and pathological data were collected from medical records. Patients were enrolled between 2015 and 2019 and followed-up until November 2022. Overall survival, disease-specific survival and disease-free survival were assessed and correlated with clinical, pathological, and molecular data. Kaplan-Meier and Cox proportional hazard regression was used to assess different risk factors. In the study, male gender, HPV-negative HNSCC (76.3%) mostly located in the oral region (78.9%) predominated. Most patients had stage IV cancer (47.4%), and the overall survival rate was 50%. HPV was found not to affect survival, indicating that in this population, classic risk factors predominate. The presence of both perineural and angioinvasion was strongly associated with survival in all analyses. Of all miRNAs assessed, only upregulation of miR-21 was consistently shown to be an independent predictor of poor prognosis and may thus serve as a prognostic biomarker in HNSCC.

VOICE CONDITION FOLLOWING SHORT-TERM ENDOTRACHEAL INTUBATION IN HEAD AND NECK SURGERY: STUDY PROTOCOL FOR CLINICAL TRIAL.

Endotracheal intubation is an airway management procedure commonly performed under general anesthesia. It is linked with postoperative voice changes. The incidence and reasons of hoarseness and vocal cord injury are not very well investigated, especially after short-term anesthesia and intubation in head and neck surgery. The aim of the study is to identify the causes of voice changes after short endotracheal anesthesia in head and neck surgery. The study will include patients scheduled for head and neck surgery under general anesthesia with endotracheal intubation up to 3 hours. There will be 3 groups of patients, as follows: thyroid surgery, non-thyroid surgery, and control group undergoing surgery outside head and neck. Videostroboscopy will be recorded before and after surgery. Further diagnostic workup will include voice status; subjective voice self-analysis; perceptive and objective acoustic voice analysis at 4 time points (preoperatively, postoperative day 2, 2 weeks and 1 month after surgery). Endotracheal intubation is a safe method of airway management although it can temporarily alter a patient's voice quality. It is not known how much of this is the result of anesthesia, general condition of the patient, or surgery. This trial is expected to shed some light on this issue.

TREATMENT OF SUBGLOTTIC STENOSIS: A SINGLE INSTITUTION EXPERIENCE.

The aim of this article is to present experiences of the Department of Otorhinolaryngology and Head and Neck Surgery, Zagreb University Hospital Center with the treatment of patients with subglottic stenosis. Subglottic stenosis is a rare congenital or acquired disorder of airway patency that is part of a wider complex of disorders known as laryngotracheal stenosis with the ultimate effect in the form of respiratory insufficiency that can be life-threatening. As an acquired condition, it is most often the result of iatrogenic damage to the larynx and trachea during invasive airway management, whether it is intubation or tracheotomy. In the case of intubation as the etiologic factor, cases of prolonged intubation were most common. Retrospective analysis of patient medical histories over a ten-year period was performed and 29 patients met the inclusion criteria. All patients were monitored for at least two years after completion of treatment. Out of a total of 29 treated patients, 20 were permanently decannulated, of which 4 have paresis of one or both vocal cords. In conclusion, there is no clear treatment protocol for patients with subglottic stenosis. The optimal modality of treatment is combined endoscopic and open surgical treatment.

SARS-CoV-2 circulation in Croatian wastewaters and the absence of SARS-CoV-2 in bivalve molluscan shellfish.

The circulation of SARS-CoV-2 in the environment has been confirmed numerous times, whilst research on the bioaccumulation in bivalve molluscan shellfish (BMS) has been rather scarce. The present study aimed to fulfil the knowledge gap on SARS-CoV-2 circulation in wastewaters and surface waters in this region and to extend the current knowledge on potential presence of SARS-CoV-2 contamination in BMS. The study included 13 archive wastewater and surface water samples from the start of epidemic and 17 influents and effluents from nine wastewater treatment plants (WWTP) of different capacity and treatment stage, sampled during the second epidemic wave. From that period are the most of 77 collected BMS samples, represented by mussels, oysters and warty venus clams harvested along the Dalmatian coast. All samples were processed according to EN ISO 15216-1 2017 using Mengovirus as a whole process control. SARS-CoV-2 detection was performed by real-time and conventional RT-PCR assays targeting E, N and nsp14 protein genes complemented with nsp14 partial sequencing. Rotavirus A (RVA) real-time RT-PCR assay was implemented as an additional evaluation criterion of virus concentration techniques. The results revealed the circulation of SARS-CoV-2 in nine influents and two secondary treatment effluents from eight WWTPs, while all samples from the start of epidemic (wastewaters, surface waters) were negative which was influenced by sampling strategy. All tertiary effluents and BMS were SARS-CoV-2 negative. The results of RVA amplification were beneficial in evaluating virus concentration techniques and provided insights into RVA dynamics within the environment and community. In conclusion, the results of the present study confirm SARS-CoV-2 circulation in Croatian wastewaters during the second epidemic wave while extending the knowledge on wastewater treatment potential in SARS-CoV-2 removal. Our findings represent a significant contribution to the current state of knowledge that considers BMS of a very low food safety risk regarding SARS-CoV-2.

THE MULTIDISCIPLINARY TEAM (MDT) IN THE TREATMENT OF HEAD AND NECK CANCER - A SINGLE-INSTITUTION EXPERIENCE.

Head and neck cancers are associated with significant morbidity and mortality despite advancements in treatment in recent decades. A multidisciplinary approach to the treatment of these diseases is thus of essential importance and is becoming the gold standard. Head and neck tumors also endanger relevant structures of the upper aerodigestive tracts, including bodily functions such as voice, speech, swallowing, and breathing. Damage to these functions can significantly influence quality of life. Thus, our study examined not only the roles of head and neck surgeons, oncologists and radiotherapists, but also the importance of the participation of different scientific professions such as anesthesiologists, psychologists, nutritionists, stomatologists, and speech therapists in the work of a multidisciplinary team (MDT). Their participation results in a significant improvement of patient quality of life. We also present our experiences in the organization and work of the MDT as part of the Center for Head and Neck Tumors of the Zagreb Clinical Hospital Center.

Evaluation of Serological Tests for Detection of Antibodies against Lumpy Skin Disease Virus.

Lumpy skin disease (LSD) is an emerging, transboundary viral pox disease affecting cattle of all ages and breeds. The serological assay for monitoring immunity following vaccination is a virus neutralization test (VNT/OIE) that determines the neutralization index (NI). The first validated enzyme-linked immunosorbent assay (ELISA; IDVet) has become commercially available, facilitating large-scale serosurveillance for LSD. Although the VNT is labor intensive and time consuming, it is still the recommended test by the OIE. Thus, in this study, we modified the virus neutralization test by employing Madin-Darby bovine kidney (MDBK) cells. The qualitative results obtained with the modified method were compared to the qualitative results obtained by VNT/OIE and ELISA. We used blood sera received within a surveillance program for LSD in 2018. In total, 291 serum samples were tested using VNT/MDBK and ELISA. Of 291 samples, 80 samples were tested by VNT/OIE and used for comparison of the performances between VNT/MDBK and VNT/OIE. The compatibility of results obtained by VNT/MDBK and VNT/OIE resulted in a kappa index of 0.9 with overall proportion agreement of 0.96. Agreement between VNT/MDBK and VNT/OIE was achieved in 56 positive and 21 negative samples. The compatibility of results obtained by ELISA and VNT/MDBK were compared on 291 samples in total and resulted in a kappa index 0.834 with overall proportion agreement of 0.955. Agreement between ELISA and VNT/MDBK was achieved in 238 positive and 40 negative samples. The results obtained demonstrated a strong correlation between VNT/MDBK and the other two methods, indicating the suitability of VNT/MDBK for the detection of the LSD virus-specific neutralizing antibodies.

Voice Outcomes as a Results of Voice Therapy after Lobectomy and Thyroidectomy.

Voice disorders are among the most common complications of thyroid surgery. It is therefore advisable to continuously monitor and report the outcomes of voice rehabilitation among people who underwent thyroid surgery in order to recognize which specific clinical actions are necessary to give those patients the maximum chance to restore quality of life. The aim of this study was to examine the outcomes of voice therapy in 35 persons (26 women and 9 men) aged between 20 and 75 years after total thyroidectomy or lobectomy. Multidimensional voice assessment using the GRBAS scale, Voice Handicap Index questionnaire, and acoustic analysis was carried out before and after voice therapy, which included relaxation and breathing exercises, laryngeal massage, resonance therapy, and the employment of the digital compression method. Since the Wilcoxon Signed Ranks Test showed significant improvements in all voice parameters after voice therapy, voice rehabilitation seems to be the essential clinical activity for thyroid surgery patients who suffer from voice disorders postoperatively.

Autologous Fat Augmentation in the Treatment of Unilateral Vocal Fold Paralysis - A 15-year Experience in a Single Institution.

Autologous fat vocal fold augmentation is a widespread surgical procedure that aims to repair glottal incompetence in patients with unilateral vocal fold paralysis (UVFP). However, there are some concerns in the literature about the long-term results of this technique. At the ENT Department of the Zagreb University Hospital Centre, this technique has been in use for more than 15 years, and a retrospective medical chart review was conducted from June 2005 to November 2019. Overall, 78 patients with UVFP met the inclusion criteria for enrolment in the study. All patients underwent at least one preoperative and two postoperative voice assessments, one early (within 3 months from surgery) and one late (at least 1 year after surgery). All tested voice outcome parameters (maximum phonation time (MPT), jitter, shimmer, noise-to-harmonic ratio (NHR)) significantly improved after surgery, both early and late postoperatively (p<0.001). The reoperation rate was only 10.3% (8/78), with the majority of patients in our series experiencing long-term benefits from this surgical procedure. According to the results of our study, autologous fat vocal fold augmentation appears to be a highly useful and effective surgical technique with long-lasting results in the majority of patients suffering from UVFP.

The emergence of porcine epidemic diarrhoea in Croatia: molecular characterization and serology.

BACKGROUND: Porcine epidemic diarrhoea (PED) is an emergent/re-emergent viral pig disease (caused by the virus belonging to the Coronaviridae family, in specific the Alphacoronavirus genus) of global importance. Clinical presentation is characterized with acute diarrhoea, vomiting and dehydration in pigs of all ages, with a possible high mortality in suckling piglets. The disease emerged in the USA in 2013 causing heavy losses, and re-emerged in Europe in 2014, but with milder consequences. RESULTS: In the spring 2016, PED-like symptoms were reported to be seen on an agricultural holding in Eastern Croatia; laboratory workup confirmed the Croatia's first PED outbreak ever. Porcine epidemic diarrhoea virus (PEDV) strain responsible for the outbreak was of the S-INDEL genotype, much the same as other European PEDV strains. In 2017, a post-outbreak serology was carried out in three counties in Eastern Croatia, revealing seropositivity in pigs bred on four large industrial holdings (9.09%). The seroprevalence across PEDV-positive holdings was up to 82.8%. The latter holdings were unanimously managed by an enterprise that had never reported PED before. CONCLUSIONS: PED has emerged in Croatian pig population causing potentially considerable losses. The circulating strain was of the S-INDEL genotype. Serological workup proved PEDV spread to another four agricultural holdings, demonstrating the importance of not only external, but also internal biosecurity measures.

Clinical antibacterial effectiveness and biocompatibility of gaseous ozone after incomplete caries removal.

OBJECTIVES: To evaluate local effect of gaseous ozone on bacteria in deep carious lesions after incomplete caries removal, using chlorhexidine as control, and to investigate its effect on pulp vascular endothelial growth factor (VEGF), neuronal nitric oxide synthase (nNOS), and superoxide dismutase (SOD). MATERIALS AND METHODS: Antibacterial effect was evaluated in 48 teeth with diagnosed deep carious lesion. After incomplete caries removal, teeth were randomly allocated into two groups regarding the cavity disinfectant used: ozone (open system) or 2% chlorhexidine. Dentin samples were analyzed for the presence of total bacteria and Lactobacillus spp. by real-time quantitative polymerase chain reaction. For evaluation of ozone effect on dental pulp, 38 intact permanent teeth indicated for pulp removal/tooth extraction were included. After cavity preparation, teeth were randomly allocated into two groups: ozone group and control group. VEGF/nNOS level and SOD activity in dental pulp were determined by enzyme-linked immunosorbent assay and spectrophotometric method, respectively. RESULTS: Ozone application decreased number of total bacteria (p = 0.001) and Lactobacillus spp. (p < 0.001), similarly to chlorhexidine. The VEGF (p < 0.001) and nNOS (p = 0.012) levels in dental pulp after ozone application were higher, while SOD activity was lower (p = 0.001) comparing to those in control pulp. CONCLUSIONS: Antibacterial effect of ozone on residual bacteria after incomplete caries removal was similar to that of 2% chlorhexidine. Effect of ozone on pulp VEGF, nNOS, and SOD indicated its biocompatibility. CLINICAL RELEVANCE: Ozone appears as effective and biocompatible cavity disinfectant in treatment of deep carious lesions by incomplete caries removal technique.

Molecular and serological survey of lyssaviruses in Croatian bat populations.

BACKGROUND: Rabies is the only known zoonotic disease of bat origin in Europe. The disease is caused by species belonging to the genus Lyssavirus. Five Lyssavirus species, i.e., European bat lyssavirus (EBLV)-1, EBLV-2, Bokeloh bat lyssavirus, Lleida bat lyssavirus, and West Caucasian bat virus, have been identified in European bats. More recently, a proposed sixth species, Kotalahti bat lyssavirus, was detected. Thus, in this study, active surveillance was initiated in order to obtain insights into the prevalence of lyssaviruses in Croatian bat populations and to improve our understanding of the public health threat of infected bats. RESULTS: In total, 455 bats were caught throughout Continental and Mediterranean Croatia. Antibodies were found in 20 of 350 bats (5.71%, 95% confidence interval 3.73-8.66). The majority of seropositive bats were found in Trbusnjak cave (Continental Croatia, Eastern part), and most seropositive bats belonged to Myotis myotis (13/20). All oropharyngeal swabs were negative for the presence of Lyssavirus. CONCLUSIONS: The presence of lyssaviruses in bat populations was confirmed for the first time in Croatia and Southeastern Europe. The results of this study suggest the need for further comprehensive analyses of lyssaviruses in bats in this part of Europe.

Changing Diagnostic Category in Development Psychiatry.

INTRODUCTION: Many children and adolescents have mental problems that undermine their normal development and functioning. It is estimated that about 10% of children and adolescents suffer from mental disorders at a sufficiently severe level to cause some degree of damage and require treatment. AIM: The aim of this paper is to determine whether there have been changes in the diagnostic categories in developmental psychiatry in children and adolescents treated at the Department for Children and Adolescent Psychiatry for the last fifteen years. SUBJECTS AND METHODS: The survey includes 844 patients treated at the Department for Child and Adolescent Psychiatry of University Clinical Center of the Republic of Srpska in the period from April 2002 to September 2017, involving only children and adolescents who were hospitalized for the first time. The sample consisted of 453 female subjects (54, 67%) and 391 male subjects (46, 33%). Subjects were divided into three groups: group 1 - hospitalization in the period from 2002 to 2007; group 2 - hospitalization in the period from 2008 to 2012; group 3 - hospitalization in the period from 2013 to September 2017. RESULTS: Female subjects accounted for more than half of the subjects within each group, with a mild increase in the number of patients in the last 4 years. In the overall sample, adolescents, aged 13 to 18 (51.66%) were the most frequent, with the lowest number of subjects under 6 years of age (3.91%). In the overall sample, the most frequent are: psychotic disorders in 18.60% of subjects; behavioral disorders and emotions in 17, 42% of subjects; suicide attempt, in 14.34% of subjects. By comparing data by groups, there has been a decline in psychotic disorders, and since 2008, adapting disorders and behavioral and emotional disorders have been most frequently diagnosed. There is an increase in the number of respondents who come from incomplete families in the last few years. About one-third of the sample (33.89%) were exposed to one or more types of abuse. 43.13% of children and adolescents with poor socio-economic status. Comorbid diseases are present in 5.92% of children and adolescents. In 26.18% of the sample, psychiatric disorders are present in the family history. The abuse of psychoactive substances was observed in 2.61% of adolescents, and this number has been increasing for the last five years. Family dysfunction is present in 57.35% of children and adolescents. CONCLUSION: In our study, there was an increase in the number of children and adolescents with behavioral disorders and adjustment disorders, as well as an increase in family dysfunctionality and psychoactive substances abuse in adolescents.

Evaluation of ELISA for the detection of rabies virus antibodies from the thoracic liquid and muscle extract samples in the monitoring of fox oral vaccination campaigns.

BACKGROUND: The main goal of oral vaccination of foxes is eradication of rabies in the red fox population as rabies reservoirs. To evaluate the success of vaccination a serological testing is conducted as a part of monitoring program. Two different methods are used regarding rabies serology: virus neutralisation test and ELISA. METHODS: In this study the reliability of BioPro ELISA was evaluated for testing haemolytic thoracic liquids and muscle extracts originated from 147 foxes in comparison to mFAVN. Also, the influence of heat treatment of samples on test results was investigated. RESULTS: The specificity of the test for not-heat treated samples was 92.98% and sensitivity 79.20%. Diagnostic validity of the ELISA compared to the mFAVN test when not-heat treated samples were used was 89.16%. The specificity of the test for heat treated samples was 79.10% and sensitivity 96.36%. Diagnostic validity of the BioPro ELISA compared to the mFAVN test for heat treated samples was 94.30%. CONCLUSION: According to this study, the BioPro ELISA is reliable tool for detection of rabies specific antibodies in the context of evaluation of oral vaccination of foxes from poor quality samples as a substitution for virus neutralisation tests.

Detection and molecular characterisation of bovine corona and toroviruses from Croatian cattle.

BACKGROUND: Bovine coronavirus (BCoV) together with bovine torovirus (BToV), both members of the Coronaviridae family, order Nidovirales are the most common viral enteric pathogens. Although studied separately, their joint occurrence and the molecular diversity in cattle in Croatia have not been investigated. METHODS: A survey is carried out on 101 fecal samples from diarrheic young and adult cattle during the 3-year period from i) one large dairy herd, ii) four small herds and iii) three nasal and paired fecal samples from calves with symptoms of respiratory disease. Samples were submitted to RT-PCR and sequencing for BCoV Nucleocapsid gene, BCoV Spike gene and BToV Spike gene. RESULTS: BCoV was detected in 78.8 % of fecal samples from symptomatic cattle and three nasal and paired fecal samples from calves with respiratory symptoms. BToV was detected in 43.2 % of fecal samples from symptomatic cattle and a fecal sample from calves with respiratory symptoms. Molecular characterisation of those viruses revealed some nucleotide and aminoacid differences in relation to reference strains. CONCLUSIONS: BToV should be regarded as a relevant pathogen for cattle that plays a synergistic role in mixed enteric infections.

Correlation of Systemic Inflammation Parameters and Serum SLFN11 in Small Cell Lung Cancer-A Prospective Pilot Study.

BACKGROUND AND OBJECTIVES: The objective of this research was to analyze the correlation of the neutrophil-to-lymphocyte ratio (NLR), C-reactive protein (CRP), soluble programmed cell death ligand 1 (sPD-L1), and Schlafen 11 (SLFN11) with the response to first-line chemotherapy in a cohort of small cell lung cancer (SCLC) patients, and to determine their potential as predictive serum biomarkers. MATERIALS AND METHODS: A total of 60 SCLC patients were included. Blood samples were taken to determine CRP, sPD-L1, and SLFN11 levels. The first sampling was performed before the start of chemotherapy, the second after two cycles, and the third after four cycles of chemotherapy. RESULTS: The patients who died earlier during the study had NLR and SLFN11 concentrations significantly higher compared to the survivor group. In the group of survivors, after two cycles of chemotherapy, the NLR ratio decreased significantly (p < 0.01), but after four cycles, the NLR ratio increased (p < 0.05). Their serum SLFN11 concentration increased significantly (p < 0.001) after two cycles of chemotherapy, but after four cycles, the level of SLFN11 fell significantly (p < 0.01). CRP, NLR, and SLFN11 were significant predictors of patient survival according to Kaplan-Meier analysis. The combination of inflammatory parameters and SLFN11 with a cutoff value above the 75th percentile of the predicted probability was associated with significantly lower overall survival in SCLC patients (average survival of 3.6 months vs. 4.8 months). CONCLUSION: The combination of inflammatory markers and the levels of two specific proteins (sPD-L1, SLFN11) could potentially serve as a non-invasive biomarker for predicting responses to DNA-damaging therapeutic agents in SCLC.

Moderate SCRIB Expression Levels Correlate with Worse Prognosis in OPSCC Patients Regardless of HPV Status.

Head and neck cancers rank as the sixth most prevalent cancers globally. In addition to traditional risk factors such as smoking and alcohol use, human papillomavirus (HPV) infections are becoming a significant causative agent of head and neck cancers, particularly among Western populations. Although HPV offers a significant survival benefit, the search for better biomarkers is still ongoing. In the current study, our objective was to investigate whether the expression levels of three PDZ-domain-containing proteins (SCRIB, NHERF2, and DLG1), known HPV E6 cellular substrates, influence the survival of HNSCC patients treated by primary surgery (n = 48). Samples were derived from oropharyngeal and oral cancers, and HPV presence was confirmed by PCR and p16 staining. Clinical and follow-up information was obtained from the hospital database and the Croatian Cancer registry up to November 2023. Survival was evaluated using the Kaplan-Meier method and Cox proportional hazard regression. The results were corroborated through the reanalysis of a comparable subset of TCGA cancer patients (n = 391). In conclusion, of the three targets studied, only SCRIB levels were found to be an independent predictor of survival in the Cox regression analysis, along with tumor stage. Further studies in a more typical Western population setting are needed since smoking and alcohol consumption are still prominent in the Croatian population, while the strongest association between survival and SCRIB levels was seen in HPV-negative cases.

Monitoring HPV Prevalence and Risk Cofactors for Abnormal Cytology in the Post-Vaccination Period among Croatian Women.

The incidence and mortality rate of cervical cancer in Croatia remains a health challenge despite screening efforts. Besides the persistent infection with HPV, the development of cancer is also associated with some cofactors. The goal of this study was to assess circulating HPV genotypes and risk factors for the development of cervical precancer after almost 16 years from the onset of HPV vaccination in Croatia. In this study, a total of 321 women attending gynecological care were evaluated. Relevant medical and demographic information, including cytology, were collected. HPV genotyping was performed by PCR. Comparing the HPV types found in circulation in the pre-vaccination (1999-2015) and post-vaccination periods (2020-2023), a statistically significant reduction in HPV 31 was noted, while the overall prevalence increased in the post-vaccination period. Besides the expected HPV positivity as a risk factor, the history of smoking was associated with LSIL or worse cytology at enrollment. For the first time, this population study revealed a statistically significant shift in the HPV genotype in the post-vaccination period, as well as the confirmation of risk factors for the development of abnormal cytology among Croatian women.

Animal models of nephrotic syndrome.

Animal models of proteinuria and nephrotic syndrome are essential tools for studying the mechanisms of action of abnormalities in individual components of the podocyte and glomerular basement membrane. In recent years a variety of in vivo models have been developed to elucidate the function of specific podocyte proteins and their role in the pathogenesis of proteinuria and glomerulosclerosis. In this overview of the animal models currently available we discuss their contribution to our mechanistic understanding and their potential use in screening for novel targeted therapies of steroid-resistant nephrotic syndrome.

Human Xp/Yp telomere analysis by Southern-STELA.

Telomeres are specialized structures designed to protect the ends of linear chromosomes. They are dynamic structures such that in normal somatic cells they constantly shorten as cell division progresses. There is compelling evidence that telomere shortening leads to cell senescence, a process perceived as the main cause of aging in higher mammals. Therefore, the features of telomere shortening are of great importance in understanding cell senescence and aging in general. By identifying unique subtelomeric regions, large enough to produce strong chemiluminescent signals, we have provided a new tool for Southern blot analysis of individual human Xp/Yp telomeres. We extend these results with quantitative fluorescence in situ hybridization using peptide nucleic acid probe (PNA Q-FISH) analysis of telomeres on the Y chromosome. Our results demonstrates unequal shortening dynamics between the p and q telomeres.

Personality Traits of Croatian University Students with Internet Addiction.

Specific personality traits may predispose individuals to various forms of addictive behaviors. This study aimed to investigate the association between personality traits of university students and Internet addiction (IA). A sample of 1051 university students was recruited from the largest university in Eastern Croatia. A structured anonymous questionnaire that included questions regarding students' sociodemographic information and Internet usage patterns, the Young Internet Addiction Test and Big Five Inventory served as a research tool. The study revealed that 1.0% of the studied sample expressed severe IA while 24.6% of study participants expressed some signs of addiction. The IA was detected in 576 (80.0%) students who used the Internet mainly for social networking, in 30 (78.9%) students who mainly used it for online gaming, and in 153 (52.2%) students who mainly used it for university assignments (p < 0.001). Higher neuroticism, higher extraversion, and higher openness to new experiences were connected with IA in general (p < 0.001). Higher neuroticism, higher extraversion, and higher openness to new experiences were significantly associated with addictive behavior during social networking (p < 0.001). Higher extraversion and higher openness to new experiences were significantly associated with addictive behavior during Internet usage for university assignments (p = 0.025), while there were no significant associations between specific personality traits and addictive behavior during online gaming (p = 0.059). Personality traits must be taken into account while developing programs and implementing interventions for preventing IA in the university student population.