Physical activity and mental health of medical students.

OBJECTIVE: Medical students usually do not meet the recommendations on the minimum level of physical activity, despite knowing the impact that physical activity has on the prevention and treatment of various diseases. Medical students are considered to be insufficiently physically active. The aim of this study is to determine the prevalence of physically active fifth-year medical students at five universities in Serbia, as well as to identify factors associated with insufficient physical activity of students. METHODS: A cross-sectional study was performed in the population of fifth-year medical students from five different universities in Serbia. The research instrument was a questionnaire specially designed based on similar research. Descriptive and analytical statistics methods were used in statistical analysis. RESULTS: The study included a total of 573 fifth-year medical students from five universities in Serbia: 311 (54.3%) Belgrade; 86 (15.0%) Kragujevac; 58 (10.1%) Nis; 66 (11.5%) Kosovska Mitrovica; 52 (9.1%) Novi Sad. Insufficient physical activity was statistically significantly associated with studying at the University of Kosovska Mitrovica (OR = 3.98, 95% CI: 1.83-8.57). There was a statistically significant difference in the frequency of anti-anxiety medications use in the last 12 months between students with sufficient and insufficient physical activity (p = 0.040) as well as in the average number of cigarettes smoked per day between students with sufficient and those with insufficient physical activity (2.82 ± 6.35 vs. 4.50 ± 8.29, p = 0.043). There was also a statistically significant difference in the average score on the Beck's depression scale between students with sufficient and students with insufficient physical activity (6.51 ± 6.59 vs. 10.03 ± 9.37, p < 0.001) and in the average score on Zung's anxiety scale (34.86 ± 8.18 vs. 38.07 ± 8.71, p = 0.003). CONCLUSION: A high percentage of medical faculty students (86.6%) are physically active. Differences in the level of physical activity were observed between students of these five universities as well as between students with different levels of physical activity.

Burnout syndrome among nurses at a military medical academy in Serbia.

OBJECTIVES: Healthcare workers are the professional group at higher risk of burnout than others. It is the underlying reason for medical errors and the general decrease in quality of patient care and is related to poor patient-healthcare worker relationships. Healthcare workers who work with military personnel have specificities compared to healthcare workers who work only with civilians. METHODS: A cross-sectional study among 171 nurses at the Military Medical Academy was conducted. The questionnaire consisted of items regarding socio-demographic and socioeconomic characteristics, lifestyle characteristics, workplace environment, workplace stress, strategies of stress management, symptoms and signs of workplace-related stress, and the Serbian version of the Maslach Burnout Inventory. RESULTS: The prevalence of burnout was 46.2%. The multivariate logistic regression analysis showed that the burnout was associated with stating that they would not choose the same profession again (OR = 4.54, 95% CI: 1.53-14.50) and with not being interested in the work (OR = 4.86, 95% CI: 1.58-14.92). CONCLUSION: The prevalence of burnout is relatively high among nurses at the Medical Military Academy in Belgrade and is associated with factors in the work environment.

Association between Chromatin Structural Organization of Peripheral Blood Neutrophils and Self-Perceived Mental Stress: Gray-Level Co-occurrence Matrix Analysis.

Methods based on the evaluation of textural patterns in microscopy, such as the "gray-level co-occurrence matrix" (GLCM) analysis are modern and innovative computer and mathematical algorithms that can be used to quantify subtle structural changes in cells and their organelles. Potential application of GLCM method in the fields of psychophysiology and psychiatry to this date has not been systematically investigated. The main objective of our study was to test the existence and strength of the association between chromatin structural organization of peripheral blood neutrophils and levels of self-perceived mental stress. The research was done on a sample of 100 healthy student athletes, and the Depression, Anxiety, and Stress Scales (DASS-21) were used for the estimation of psychological distress. Chromatin textural homogeneity and uniformity were negatively correlated (p < 0.01) with mental distress and had relatively good discriminatory power in differentiating participants with normal and elevated stress levels. As an addition, we propose the creation of a machine learning model based on binomial logistic regression that uses these and other GLCM features to predict stress elevation. To the best of our knowledge, these results are one of the first to establish the link between neutrophil chromatin structural organization quantified by the GLCM method and indicators of normal psychological functioning.

Myocardial damage in multisystem inflammatory syndrome associated with COVID-19 in children and adolescents.

BACKGROUND: In multisystem inflammatory syndrome in children (MIS-C) temporarily associated with coronavirus disease-19 (COVID-19), myocardial damage has been reported. MATERIALS AND METHODS: A retrospective observational cohort study included children under 18 who had a myocardial injury related to COVID-19 treated in mother and child health institute from April 2020 to August 2020. Myocardial injury related to COVID-19 was manifested by elevated serum cardiac troponin and NT-proBNP with LV dysfunction, arrhythmias, and coronary arteries (CAs) dilatation or aneurysms. During the short-term follow-up, cardiac testing (electrocardiography, laboratory analysis, echocardiography, 24-h Holter monitoring, exercise stress test, and cardiac magnetic resonance) was performed. RESULTS: Six male adolescents (14.7 ± 2.4 years) were included in the analysis (2/6 had MIS-C shock syndrome). All patients had elevated acute-phase reactants and NT-proBNP, whereas troponins were elevated in 5/6 patients. Echocardiography revealed left ventricular (LV) systolic dysfunction (EF 45.2 ± 6.9%); 2/6 had dilated CAs. IVIG was prescribed to all patients with MIS-C. Four patients required inotropic drug support. During hospitalization, a significant reduction of CRP, LDH, NT-proBNP, and D-dimer (P < 0.05) was registered. LV systolic function recovery was registered 3 days after applied therapy (P < 0.001). None of the patients developed dilated cardiomyopathy or CA aneurysms. CONCLUSIONS: With early recognition and adequate MIS-C therapy, children recovered entirely, maintained in the short-term follow-up period.

Does Colchicine Substitute Corticosteroids in Treatment of Idiopathic and Viral Pediatric Pericarditis?

Background and Objectives: Recurrence of pericarditis (ROP) is an important complication of the acute pericarditis. The aim of this study was to analyse the influence of aetiology, clinical findings and treatment on the outcome of acute pericarditis. Methods: Data were retrospectively collected from medical records of patients treated from 2011 to 2019 at a tertiary referent heart paediatric center. Results: Our investigation included 56 children with idiopathic and viral pericarditis. Relapse was registered in 8/56 patients, 2/29 (7.41%) treated with nonsteroidal anti-inflammatory drugs (NSAID) and 6/27 (28.57%) treated with corticosteroids (CS) and NSAID. Independent risk factors for ROP were viral pericarditis (p = 0.01, OR 31.46), lack of myocardial affection (p = 0.03, OR 29.15), CS use (p = 0.02, OR 29.02) and ESR ≥ 50 mm/h (p = 0.03, OR 25.23). In 4/8 patients the first recurrence was treated with NSAID and colchicine, while treatment of 4/8 patients included CS. Children with ROP treated with CS had higher median number of recurrence (5, IQR: 2-15) than those treated with colchicine (0, IQR: 0-0.75). Conclusions: Independent risk factors for recurrence are CS treatment, viral aetiology, pericarditis only and ESR ≥ 50 mm/h. Acute pericarditis should be treated with NSAID. Colchicine and NSAID might be recommended in children with the first ROP.

An improved design of optical sensor for long-term measurement of arterial blood flow waveform.

We present here the improved design and development of optical sensor for non-invasive measurements of arterial blood flow waveform. The sensor is based on a physical principle of reflective photoplethysmography (PPG). As the light source we used serially connected infrared diodes whereas NPN silicon phototransistors were used as light detectors. The electronic components were molded into square package and poured with silicone. Such preparation produced an elastic superficies that allowed excellent attachment of the sensor on the skin's surface. Moreover, a serial connection of infrared diodes and phototransistors completely eliminated signal artifacts caused by minor muscle contractions. The sensor recording performances were examined at the photoplethysmographic sites on three different arteries; the commune carotid, femoral and radial and, on each site the sensor demonstrated remarkable capability to make a consistent, reproducible measurements. Because of the advantageous physical and electrical properties, the new sensor is suitable for various cardiovascular diagnostics procedures, especially when long-term measurements of arterial blood flow waveform are required, for monitoring of different parameters in cardiovascular units and for research.

Gray level co-occurrence matrix algorithm as pattern recognition biosensor for oxidopamine-induced changes in lymphocyte chromatin architecture.

We demonstrate that a proapoptotic chemical agent, oxidopamine, induces dose dependent changes in chromatin textural patterns which can be quantified using the Gray level co-occurrence matrix (GLCM) method. Peripheral blood (heparin-pretreated) samples were treated with oxidopamine (6-OHDA, 6-hydroxydopamine) to achieve effective concentrations of 100, 200 and 300µM. The samples were smeared on microscope slides and fixated in methanol. The smears were stained using a modification of Feulgen method for DNA visualization. For each stained smear, a sample of 30 lymphocyte chromatin structures were visualized and analyzed. This way, textural parameters for a total of 120 nuclei micrographs were calculated. For each chromatin structure, five different GLCM features were calculated: angular second moment, GLCM entropy, inverse difference moment, GLCM correlation, and GLCM variance. Oxidopamine induced the rise of the values of GLCM entropy and variance, and the reduction of angular second moment, correlation, and inverse difference moment. The trends for GLCM parameter changes were found to be highly significant (p<0.001). These results indicate that GLCM mathematical algorithm might be successfully used in detection and evaluation of discrete early apoptotic structural changes in Feulgen-stained chromatin of peripheral blood lymphocytes that are not detectable using conventional microscopy/cell biology techniques.

Screening commercial drivers for obstructive sleep apnea: translation and validation of Serbian version of Berlin Questionnaire.

PURPOSE: Obstructive sleep apnea (OSA) can lead to severe health consequences. Drivers of motor vehicles with untreated or undiagnosed OSA have a greater risk of traffic accidents. Use of self-reported questionnaires is the first step in OSA diagnosis. The main aim of this study was to perform the translation and validation of Berlin Questionnaire in a sample of commercial drivers. METHODS: After formal translation, validation was performed on a sample of commercial drivers and included evaluation of internal consistency, test-retest reliability, construct and criterion validity. Full-night attended polysomnography or cardiorespiratory polygraphy was used for OSA diagnosis. RESULTS: One hundred male participants, 24-62 years old, were included. Berlin Questionnaire classified 35 % subjects as potential OSA patients. Polysomnography confirmed OSA in 58 % of the subjects. Berlin Questionnaire showed good internal consistency (Cronbach's alpha 0.82-first category, 0.73-0.95-second category). Test-retest reliability (Cohen's kappa 0.78) was adequate. Berlin score was significantly correlated with OSA category and apnea-hypopnea index (AHI). Sensitivity of Berlin Questionnaire was from 50.9 (AHI ≥ 5) to 75 % (AHI ≥ 30), while specificity ranged from 86 to 70.5 %. CONCLUSIONS: Berlin Questionnaire (Serbian version) showed good measurement properties, creating basis for further research of its usefulness as OSA screening tool in populations of interest.

Chromatin Fractal Organization, Textural Patterns, and Circularity of Nuclear Envelope in Adrenal Zona Fasciculata Cells.

Despite previous research efforts in the fields of histology and cell physiology, the relationship between chromatin structural organization and nuclear shape remains unclear. The aim of this research was to test the existence and strength of correlations between mathematical parameters of chromatin microarchitecture and roundness of the nuclear envelope. On a sample of 240 nuclei of adrenal zona fasciculata cells stained using the DNA-specific Feulgen method, we quantified fractal parameters such as fractal dimension and lacunarity, as well as textural parameters such as angular second moment (ASM), entropy, inverse difference moment, contrast, and variance. Circularity of the nuclear envelope was determined from the nuclear area and perimeter. The results indicate that there is a statistically significant negative correlation between chromatin ASM and circularity. Moreover, there was a statistically significant positive correlation between chromatin fractal dimension and envelope circularity. This is the first study to demonstrate these relationships in adrenal tissue, and also one of the first studies to test the connection between circularity and fractal and gray-level co-occurrence matrix parameters in DNA-specific Feulgen stain. The results could be useful both as an addition to the current knowledge on chromatin/nuclear envelope interactions, and for design of future computer-assisted research software for evaluation of nuclear morphology.

Levels of transforming growth factor ß1 during first six months of peritoneal dialysis.

Transforming-growth factor ß1 (TGF-ß1) is a powerful cytokine involved in physiological processes of growth, differentiation, gene expression, embryogenesis, tissue remodelling, wound healing as well as tumorigenesis, immunosuppression and fibrosis, like peritoneal membrane fibrosis on long-term peritoneal dialysis (PD) treatment. The aims of this study were to determine TGF-ß1 levels in serum (s) and drained dialysate (dd), to assess their relations to sex, age, diabetes, dialysis modality, peritonitis and use of erythropoiesis stimulating agents (ESAs), inhibitors of angiotensin-converting enzyme (ACEi) and/or statins in 20 patients, 11 men and 9 women, mean age 62.90 ± 12.69 years, free of peritonitis during the first 6 months of PD treatment. There was no statistically significant difference in TGF-ß1 concentrations in serum and drained dialysate at the beginning and after first 6 months of chronic PD, in patients of different sex, age and diabetic patients versus non-diabetic. The significant positive correlations between sTGF-ß1 levels and glycemia at the beginning and cholesterolemia after 6 months of PD treatment suggest higher TGF-ß1 concentrations in patients with unfavorable metabolic profile. Expression of TGF-ß1 in effluent dialysate was significantly lower in patients on chronic PD using ACEi therapy, suggesting ACEi to have a protective effect on peritoneal membrane. Patients on ESA had slightly lower sTGF-ß1 concentrations after the first 6 months of PD treatment.

Work-Related Factors as Predictors of Burnout in Serbian Nurses Working in Hemodialysis.

Nurses who work in hemodialysis (HD) are considered highly susceptible to burnout due to their close relationship with incurable patients and handling sophisticated machinery. A total of 210 nurses from 12 state-owned HD centers in the Republic of Serbia anonymously completed a background information questionnaire providingfactual data on nurses' sociodemographic characteristics and working conditions using the Maslach Burnout Inventory--Health Services Survey. Almost half of the nurses (42.9%) were experiencing burnout High emotional exhaustion, high depersonalization, and low level of personal accomplishment were present in 40.9%, 8.6%, and 31.3% of nurses, respectively. The number of children, involuntary choice of current position, and unwillingness to choose the same type of job again were significant predictors of burnout. Our population of nurses working in HD was more affected by emotional exhaustion than their colleagues in other countries, but maintained high level of empathy and feeling ofpersonal accomplishment.

Effects of ghrelin on the structural complexity of exocrine pancreas tissue architecture.

Recent studies have shown that ghrelin increases pancreatic exocrine secretion. However, the potential effects of ghrelin on the morphology of exocrine pancreas (EP) remain unknown. In this work, using fractal analysis, we demonstrate that centrally administered ghrelin increases structural complexity and tissue disorder in rat EP. The study was carried out on a total of 40 male Wistar rats divided into four groups (n = 10): ghrelin-treated animals (average age, 1.5 months), ghrelin-treated animals (8.5 months), and controls (1.5 and 8.5 months). The pancreas tissue sections were stained with hematoxylin/eosin and visualized by light microscopy. For each animal, the average values of tissue fractal dimension, lacunarity, as well as parameters of co-occurrence matrix texture, were determined using tissue digital micrographs. The results indicate that ghrelin administration increases EP fractal dimension and textural entropy, and decreases lacunarity, regardless of the age. To our knowledge, this is the first study to investigate the effects of ghrelin on the morphological properties of pancreatic tissue, and also the first to apply fractal and textural analysis methods in quantification of EP tissue architecture.

Percutaneous Modified Blalock-Taussig Shunt Closure in a Patient with Isolated Right Ventricular Hypoplasia.

Clinical presentation, course, and treatment for patients with isolated right ventricular (RV) hypoplasia (IRVH) depends on the degree of hypoplasia that is present-this is a spectrum from spontaneous maturation to Fontan circulation over time. An 8-month-old infant presented with IRVH; in the patient, a modified Blalock-Taussig (MBTS) shunt was closed percutaneously after spontaneous RV function recovery. A female newborn was diagnosed with differential cyanosis at birth. The echocardiography showed a hypertrophic RV with a small cavity, a right-left shunt on the atrial septal defect, an almost closed ductus arteriosus (DA), and a small tricuspid valve ring (Z-score-2) with mild regurgitation (pressure gradient 30 mmHg). On the 4th day of life, the patient showed deepened cyanosis and hyperlactatemia was registered. The echocardiography examination revealed a closed DA. Right ventriculography performed on the 5th day of life evidenced the presence of a small hypertrabeculated RV. The pressure in the RV increased. A right-side MBTS was created on the 6th day of life. Further echocardiographic findings indicated a gradual development of the RV and a decrease in RV pressure. MBTS occlusion was performed when the patient was 8 months old. Vital parameters were monitored invasively and noninvasively after the balloon occlusion of MBTS. Percutaneous MBTS occlusion was successfully performed using an Amplatzer vascular plug 2 (AVP2). During the follow-up period, the patient was found to have maintained a normal percutaneous oxyhaemoglobin blood saturation.

The Efficacy of Focused Extracorporeal Shock Wave Therapy and Ultrasound Therapy in the Treatment of Calcar Calcanei: A Randomized Study.

The prospective, simple randomized study assesses the effect of focused extracorporeal shock wave therapy (f-ESWT) on pain intensity and calcification size compared to the application of ultrasound physical therapy in treating patients with calcar calcanei. A total of 124 patients diagnosed with calcar calcanei were consecutively included in the study. The patients were divided into two groups: the experimental group (n = 62), which included the patients treated with f-ECWT, and the control group (n = 62), consisting of patients treated with the standard ultrasound therapy method. The experimental group's patients received ten therapy applications spaced seven days apart. The patients in the control group had ten ultrasound treatments on ten consecutive days over two weeks. All patients in both groups were tested using the Visual Analog Scale (VAS) to measure pain intensity before the beginning and at the end of treatment. The size of the calcification was assessed in all patients. The study hypothesizes that f-ESWT reduces the pain and the size of the calcification. Pain intensity reduction was registered in all patients. The calcification size in patients in the experimental group was reduced from the initial range of 2 mm-15 mm, to a content of 0.0 mm-6.2 mm. The calcification size in the control group ranged from 1.2 to 7.5 mm, without any change. None of the patients experienced any adverse reactions to the therapy. Patients treated with standard ultrasound therapy did not have a statistically significant reduction in the calcification size. In contrast, the patients in the experimental group treated with f-ESWT showed a substantial decrease in the calcification size.

Mechanisms of redox balance and inflammatory response after the use of methylprednisolone in children with multisystem inflammatory syndrome associated with COVID-19.

Background: Multisystem inflammatory syndrome in children (MIS-C) associated with being infected with coronavirus-19 (COVID-19) is a life-threatening condition resulting from cytokine storm, increased synthesis of reactive oxygen species (ROSs), and hyperinflammation occurring in genetically predisposed children following an infection with SARS-CoV-2. Aim: The primary aims of our study were to identify changes in the activity of antioxidant enzymes in erythrocytes and total oxidative status in plasma after being treated with methylprednisolone (MP). Methods: A prospective cohort study of 67 children (56.7% male) under 18 with MIS-C being treated with MP was conducted at the Mother and Child Health Institute from January 2021 to April 2022. The impact of the therapy was assessed on the basis of the clinical condition, haematological and biochemical blood parameters, and echocardiographic findings. Results: 59.7% of patients presented cardiovascular (CV) manifestations, while myocardial dysfunction was observed in half of all patients (50.7%). A severe clinical course was observed in 22/67 patients. Children with CV involvement had a significantly higher relative concentration of B lymphocytes and lower relative concentration of NK cells than patients without CV issues (p < 0.001 and p = 0.004, respectively). Patients with severe MIS-C had a lower relative count of NK cells than those with moderate MIS-C (p = 0.015). Patients with myocardial dysfunction had a higher total oxidative plasma status (TOPS) than children without (p = 0.05), which implicates pronounced oxidative stress in the former cohort. In patients with shock, lower erythrocytes superoxide dismutase (SOD) activity was observed on admission compared to patients without shock (p = 0.04). After MP was administered, TOPS was significantly reduced, while catalase (CAT) and SOD activity increased significantly. Treatment failure (TF) was observed in 6 patients, only females (p=0.005). These patients were younger (p=0.05) and had lower CAT activity on admission (p=0.04) than patients with favorable treatment responses. In the group of patients with TF, TOPS increased after treatment (before 176.2 ± 10.3 mV, after 199.0 ± 36.7 mV). Conclusion: MP leads to rapid modulation of TOPS and increases the activity of antioxidant enzymes in erythrocytes resulting in clinical and echocardiographic improvement. Based on the observed changes in the activity of the antioxidant enzymes, we can conclude that s hydrogen peroxide is the dominant ROS in patients with MIS-C. Patients with TF showed reduced CAT activity, whereas the treatment with MP led to pronounced oxidation. This implies that low CAT activity may be a contraindication for using MP.

Analysis of cardiac manifestation and treatment of multisystem inflammatory syndrome in children related to SARS-CoV-2.

Cardiovascular manifestations are common (35-100%) in the multisystem inflammatory syndrome in children. Our study aimed to analyze treatment impact and cardiovascular involvement in patients with multisystem inflammatory syndrome in children. The retrospective cohort included 81 patients treated between April 2020 and December 2021 (9.3±4.6 years). Elevated cardiac troponin I and pro-B-type natriuretic peptide were observed in 34.2% and 88.5% of patients, respectively. Myocardial dysfunction was observed in 50.6%. Children older than 10 years had a 4-fold increased risk of myocardial dysfunction (odds ratio [OR] 3.6, 95% confidence interval [CI] 1.4-8.9; p=0.006). A moderate negative correlation was proved between left ventricle ejection fraction and C-reactive protein (rr = - 0.48; p < 0.001). More than one-fifth of the patients presented with shock. Coronary artery dilatation was observed in 6.2% of patients. Mild pericardial effusion was detected in 27.1% of children. On standard electrocardiogram, 52.6% of children had negative T waves in the inferior and/or precordial leads; transient QTc prolongation was registered in 43% of patients. Treatment failure was observed in 19 patients. Patients initially treated with intravenous immunoglobulins had 10-fold higher chances for treatment failure than patients treated with corticosteroids (OR 10.6, 95% CI 3,18 - 35.35; p < 0.001). Cardiovascular manifestations were observed in more than half of the patients, with acute myocardial dysfunction being the most common, especially in children older than 10 years. We established a negative association between the degree of elevation of inflammatory markers and left ventricular ejection fraction. Patients treated with intravenous immunoglobulins who had cardiovascular manifestations had treatment failures more frequently than patients treated with corticosteroids.

Computational approaches for evaluating morphological changes in the corneal stroma associated with decellularization.

Decellularized corneas offer a promising and sustainable source of replacement grafts, mimicking native tissue and reducing the risk of immune rejection post-transplantation. Despite great success in achieving acellular scaffolds, little consensus exists regarding the quality of the decellularized extracellular matrix. Metrics used to evaluate extracellular matrix performance are study-specific, subjective, and semi-quantitative. Thus, this work focused on developing a computational method to examine the effectiveness of corneal decellularization. We combined conventional semi-quantitative histological assessments and automated scaffold evaluations based on textual image analyses to assess decellularization efficiency. Our study highlights that it is possible to develop contemporary machine learning (ML) models based on random forests and support vector machine algorithms, which can identify regions of interest in acellularized corneal stromal tissue with relatively high accuracy. These results provide a platform for developing machine learning biosensing systems for evaluating subtle morphological changes in decellularized scaffolds, which are crucial for assessing their functionality.

Immunomodulatory actions of central ghrelin in diet-induced energy imbalance.

We investigated the effects of centrally administered orexigenic hormone ghrelin on energy imbalance-induced inflammation. Rats were subjected for four weeks to three different dietary regimes: normal (standard food), high-fat (standard food with 30% lard) or food-restricted (70%, 50%, 40% and 40% of the expected food intake in 1st, 2nd, 3rd and 4th week, respectively). Compared to normal-weight controls, starved, but not obese rats had significantly higher levels of proinflammatory cytokines (TNF, IL-1ß, IFN-γ) in the blood. When compared to normally fed animals, the hearts of starved and obese animals expressed higher levels of mRNAs encoding proinflammatory mediators (TNF, IL-1ß, IL-6, IFN-γ, IL-17, IL-12, iNOS), while mRNA levels of the anti-inflammatory TGF-ß remained unchanged. Intracerebroventricular (ICV) injection of ghrelin (1 µg/day) for five consecutive days significantly reduced TNF, IL-1ß and IFN-γ levels in the blood of starved rats, as well as TNF, IL-17 and IL-12p40 mRNA expression in the hearts of obese rats. Conversely, ICV ghrelin increased the levels of IFN-γ, IL-17, IL-12p35 and IL-12p40 mRNA in the heart tissue of food-restricted animals. This was associated with an increase of immunosuppressive ACTH/corticosterone production in starved animals and a decrease of the immunostimulatory adipokine leptin both in food-restricted and high-fat groups. Ghrelin activated the energy sensor AMP-activated protein kinase (AMPK) in the hypothalamus and inhibited extracellular signal-regulated kinase (ERK) in the hearts of obese, but not starved rats. Therefore, central ghrelin may play a complex role in energy imbalance-induced inflammation by modulating HPA axis, leptin and AMPK/ERK signaling pathways.

Histomorphometric features of ventral prostate in different aged rats after central ghrelin treatment.

Ghrelin, the endogenous ligand of growth hormone secretagogue receptor type 1a (GHS-R1a), has emerged as pleiotropic modulator of diverse biological functions, including energy homeostasis and recently, reproduction. The influence of intracerebroventricularly (ICV) administered ghrelin (1 µg/day/rat for 5 days) to rats of different ages, i.e, peripubertal (38 days), adult (60 days) and middle-aged (180 days) on the ventral prostate size and morphology, serum testosterone levels and testis weight was examined. Ghrelin treatment significantly increased (p < 0.05) absolute ventral prostate weight in peripubertal and middle-aged rats, by 27% and 37% respectively, due to enhancement of epithelial and/or luminal compartment of the gland. In adult rats, both absolute and relative volumes of the acinar lumen were significantly decreased (p < 0.05), by 38% and 44% respectively, which was associated with significant increases (p < 0.05) in relative and absolute volumes of interacinar stroma, whereas ventral prostate weigh was unchanged. Irrespective of animal age, ghrelin did not affect serum testosterone levels. These are the first results of ghrelin treatment effects on healthy prostate appearance, which allow us to conclude that the rat ventral prostate response to ghrelin depends on the developmental stage of animals. Our results merit further investigations and may have clinical implications, especially in the light of data on possible role of ghrelin in prostate hypertrophy and adenomas.

The Validity and Reliability of the Serbian Version of the Smartphone Addiction Scale-Short Version.

Background and Objectives: Smartphone use has been rapidly increasing worldwide, which has brought possible smartphone addiction into the focus of research. In order to identify potential smartphone addicts, several scales were developed to assess smartphone addiction. Among them, the Smartphone Addiction Scale was frequently used. The study aimed to test the reliability and validity of the Serbian version of the SAS-SV and estimate smartphone addiction prevalence among medical students. Materials and Methods: The study was conducted in December 2018 on a convenience sample of 323 third-year medical students. The cross-cultural adaptation was performed following the well-established guidelines for cross-cultural adaptation of self-reported measures. Exploratory factor analysis was used to examine the structure of the questionnaire. Factor extraction was performed by principal component analysis with Varimax rotation. For test-retest reliability, students completed the questionnaire twice within seven days. Results: The Serbian version of the SAS-SV showed good internal consistency (Cronbach's alpha = 0.89) and excellent reliability for test-retest scores (ICC = 0.94, 95% CI = 0.92-0.96). Factor analysis supported the extraction of one factor, which explained 51.538% of the variance. To explore convergent validity furthermore, the SAS-SV was correlated with time indicators of smartphone use. According to cut-off values for the SAS-SV score, 19.5% of students could be regarded as "addicted", and often spent more time on smartphones and social networks on working days and weekends than "not addicted" students. Conclusions: The Serbian version of the SAS-SV is a reliable and valid instrument for detecting smartphone addiction among university students. Further research on this issue is encouraged to enable a better understanding of this ever-increasing public health issue.