Artificial intelligence diagnostic accuracy in fracture detection from plain radiographs and comparing it with clinicians: a systematic review and meta-analysis.

PURPOSE: Fracture detection is one of the most commonly used and studied aspects of artificial intelligence (AI) in medicine. In this systematic review and meta-analysis, we aimed to summarize available literature and data regarding AI performance in fracture detection on plain radiographs and various factors affecting it. METHODS: We systematically reviewed studies evaluating AI algorithms in detecting bone fractures in plain radiographs, combined their performance using meta-analysis (a bivariate regression approach), and compared it with that of clinicians. We also analyzed the factors potentially affecting algorithm performance using meta-regression. RESULTS: Our analysis included 100 studies. In 83 studies with confusion matrices, AI algorithms showed a sensitivity of 91.43% and a specificity of 92.12% (Area under the summary receiver operator curve = 0.968). After adjustment and false discovery rate correction, tibia/fibula (excluding ankle) fractures were associated with higher (7.0%, p=0.004) AI sensitivity, while more recent publications (5.5%, p=0.003) and Xception architecture (6.6%, p<0.001) were associated with higher specificity. Clinicians and AI showed similar specificity in fracture identification, although AI leaned to higher sensitivity (7.6%, p=0.07). Radiologists, on the other hand, were more specific than AI overall and in several subgroups, and more sensitive to hip fractures before FDR correction. CONCLUSIONS: Currently available AI aids could result in a significant improvement in care where radiologists are not readily available. Moreover, identifying factors affecting algorithm performance could guide AI development teams in their process of optimizing their products.

Application of the Life Grid in Oral Health Research: A Scoping Review.

AIM: The life grid is a retrospective interview-based tool used to enhance recall of past events. This scoping review examines the use of the life grid in oral health research and its applications. METHODS: Using the Joanna Briggs Institute framework, Medline (Ovid), CINAHL, PsycInfo, ERIC, MedEdPortal, Web of Science Core Collection, ProQuest, and Google Scholar were searched with "life grid" and "oral" as initial keywords. Then, two reviewers screened the records independently. Studies published until April 21, 2022, were added, regardless of language. Data were summarised narratively and in a comprehensive table focused on seven main areas. RESULTS: A total of 22 studies were included from 724 initially identified records. The life grid was used in different forms, in various qualitative, longitudinal, and cross-sectional studies with participants of different ages. Eight studies used the life grid at the beginning of the interview, four during the process, and one at the end. The ability to reduce recall bias, increase data reliability, establish rapport with participants, and ensure information accuracy were among the most commonly cited benefits of using the life grid in oral health research, particularly in oral cancer research. CONCLUSIONS: The life grid is a flexible tool used in a variety of structures and applications in oral health research. Positive impacts have been reported by both researchers and participants. This review highlights the potential of the life grid as a data collection and interview tool in oral health research and dental education.

Design of two compact waveguide display systems utilizing metasurface gratings as couplers.

We propose two approaches to design compact head mount display (HMD) systems employing metasurface gratings. In the first approach, we design and simulate a monocular optical waveguide display by applying crystalline-silicon elliptical-shaped metasurface arrays as couplers on a right trapezoid waveguide to achieve large field of view (FOV) horizontally. As such, we achieve a FOV as large as 80° that is approximately 80% higher than the FOV in traditional waveguide systems based on diffractive gratings. In the second approach, considering the polarization sensitivity feature in metasurfaces and employing the proposed structures in the first technique, we design a metasurface grating as the input coupler in a binocular HMD system. The suggested structure diffracts incident light into two opposite directions with a 53.7° deflection angle on each side. We use the finite difference time domain method to study the behavior of the proposed systems.

Treatment of normal hydrocarbons contaminated water by combined microalgae - Photocatalytic nanoparticles system.

Two species of microalgae (Chlorella vulgaris and Dunaliella tertiolecta) as the biological agents along with ZnO nanoparticles as the photocatalyst were used to investigate the hydrocarbon removal efficiency from oily water samples. Firstly, the toxicities of the photocatalyst, normal paraffine hydrocarbons and their combination towards the microalgae were evaluated in terms of cell growth and chlorophyll content. The capability of algae to absorb the nanoparticles in the aqueous phase was confirmed by FT-IR spectroscopy. Then, the hydrocarbon removal efficiencies of the algae, photocatalyst and the combined photocatalyst-algae system were studied by measuring the residual hydrocarbon content of the samples. Results indicated that despite of the growth inhibitory effects of n-alkanes and nanoparticles on the examined algae, both of them could survive in the system. Dunaliella tertiolecta was more affected by normal paraffins while Chlorella vulgaris was more sensitive to ZnO nanoparticles. Both of the studied species were capable of hydrocarbon removal and the efficiency of Chlorella vulgaris was superior. The combination of algae and nanoparticles was also proved to have a synergistic effect on degradation of the hydrocarbon content of the medium. The obtained removal efficiencies for initial hydrocarbon concentrations of 0.05%, 0.1% and 0.5% (v/v) were 100%, 78% and 42% for Dunaliella tertiolecta-ZnO and 100%, 93% and 88% for Chlorella vulgaris- ZnO system, respectively. It can be concluded that the examined microalgae-nanoparticle system can be considered as a final polishing step in hydrocarbons removal from oily waters.

Invasive fungal consecutive infections in a patient with acute myeloid leukaemia.

A woman with AML who became febrile and neutropenic after chemotherapy. At the first, Aspergillus was isolated from a sinus biopsy. After 4 weeks, while she was taking voriconazole, another episode of fever combined with dry coughs was detected. Fungal culture and histopathology of sinus biopsy revealed mucormycosis.

Sperm DNA fragmentation affects epigenetic feature in human male pronucleus.

To evaluate whether the sperm DNA fragmentation affects male pronucleus epigenetic factors, semen analysis was performed and DNA fragmentation was assessed by the method of sperm chromatin structure assay (SCSA). Human-mouse interspecies fertilisation was used to create human male pronucleus. Male pronucleus DNA methylation and H4K12 acetylation were evaluated by immunostaining. Results showed a significant positive correlation between the level of sperm DNA fragmentation and DNA methylation in male pronuclei. In other words, an increase in DNA damage caused an upsurge in DNA methylation. In the case of H4K12 acetylation, no correlation was detected between DNA damage and the level of histone acetylation in the normal group, but results for the group in which male pronuclei were derived from sperm cells with DNA fragmentation, increased DNA damage led to a decreased acetylation level. Sperm DNA fragmentation interferes with the active demethylation process and disrupts the insertion of histones into the male chromatin in the male pronucleus, following fertilisation.

Hyperinsulinemic hypoglycemia after gastric bypass surgery: what's up and what's down?

Obesity is a global public health problem and attempts to treat this condition using life style with and without pharmacological interventions have not been successful in majority of obese individuals. To date, the most effective treatment for obesity is weight loss surgery. One of the most widely used procedures to treat obesity worldwide, Roux-en-Y gastric bypass surgery (RYGB), has shown to induce diabetes remission in addition to significant and sustainable weight loss. As the number of this procedure performed over the last two decades increased, it has become clear that a subgroup of individuals develop postprandial hypoglycemia several years after surgery. This debilitating late complication of RYGB is often associated with loss of consciousness or seizures, and in severe cases, it is only partially responsive to diet modification or other available therapeutic options. The diagnosis is often a challenge resulting in delays in receiving care in the affected individuals. Although the underlying mechanisms are under current investigations, growing evidence suggest that a combination of exaggerated meal-derived nutrient appearance to systemic circulation and altered islet and gut hormone response after eating have a role in pathogenesis of this condition. The goal of this review is to highlight new perspectives regarding this life-threatening complication of RYGB. The etiology, diagnosis, recommendation on how to distinguish from classic dumping and current available treatment based on literature review will be discussed. In addition, physiologic changes after gastric bypass predisposing to hypoglycemia syndrome will be highlighted.International Journal of Obesity advance online publication, 31 October 2017; doi:10.1038/ijo.2017.257.

Validity and reliability of the Evidence Utilisation in Policymaking Measurement Tool (EUPMT).

BACKGROUND: As a well-known theory in studying the effective factors on behaviour, the theory of planned behaviour (TPB) is frequently used in evaluating the health behaviour of people and healthcare providers, but rarely applied in studying the behaviour of health policymakers. The aim of the present study is to design and validate a TPB-based measurement tool for evidence utilisation in health policymaking (the EUPMT) through a mixed approach using confirmatory factor analysis. METHODS: The study population consisted of all the specialised units and their employees in the five deputies of Iran's Ministry of Health and Medical Education in 2013. All those eligible were invited to participate in the study, which comprised 373 persons. The reliability of the EUPMT was determined through test-retest and internal consistency. Additionally, its validity was determined by face, content, convergent, discriminant and construct validities. SPSS-20 and LISREL-8.8 were employed to analyse the data. To assess the fitness of the measurement models, three groups of indices were used, i.e. absolute, relative and parsimonious. RESULTS: The content and face validities of the tool were 83% and 67%, respectively. Cronbach's alpha of different constructs ranged from 0.7 to 0.9. In the test-retest method, the intra-class correlations were between 0.75 and 0.87. Confirmatory factor analysis showed that the penta-factorial structure of the experimental data had acceptable fitness with the TPB (GFI = 0.86, NFI = 0.94, RSMEA = 0.075). CONCLUSION: TPB is able to explain the behaviour of evidence utilisation in health policymaking. The finalised TPB-based tool has relatively good reliability and validity to assess evidence utilisation in health policymaking. The EUPMT can be applied to determine the status quo of evidence utilisation in health policymaking, whilst designing interventions for its improvement and assessing their outcomes.

Records in fractal stochastic processes.

The record statistics in stationary and non-stationary fractal time series is studied extensively. By calculating various concepts in record dynamics, we find some interesting results. In stationary fractional Gaussian noises, we observe a universal behavior for the whole range of Hurst exponents. However, for non-stationary fractional Brownian motions, the record dynamics is crucially dependent on the memory, which plays the role of a non-stationarity index, here. Indeed, the deviation from the results of the stationary case increases by increasing the Hurst exponent in fractional Brownian motions. We demonstrate that the memory governs the dynamics of the records as long as it causes non-stationarity in fractal stochastic processes; otherwise, it has no impact on the record statistics.

DECREASED FERTILIZATION: HUMAN SPERM DNA FRAGMENTATION AND IN VITRO MATURATION OF OOCYTE IN STIMULATED ICSI CYCLES.

OBJECTIVE: The aim of this study was to evaluate the impact of sperm DNA fragmentation (SDF) on fertilization rate, and sperm nuclear decondensation after intracytoplasmic injection of sperm (ICSI) into cumulus-free germinal vesicle (GV) oocytes from stimulated cycles. METHODS AND STUDY DESIGN: After the retrieval of oocytes, the GV oocytes were cultured for 24 h. Oocytes that liberated polar bodies were injected with processed semen, and were used to evaluate SDF level. Based on SDF, the data were categorized into two groups. Group I in which SDF≤ 30% and group II in which SDF > 30%. Fertilization (presence of two pronuclei) was checked 16-19 h after ICSI. Unfertilized oocytes were stained by Hoechst 33258 and examined to evaluate the undecondensed sperm head in oocyte. The rates of maturation, fertilization in fertilized IVM oocytes and the percentage of undecondensed sperm in the unfertilized oocytes were assessed according to SDF. RESULTS: Out of 146 GV oocytes that were subjected to IVM, 101 (69 %) developed to metaphase II. The fertilization rate of IVM oocytes in group II was significantly lower than that in group I (P < 0.05). Moreover, group I, had 25 % of their unfertilized oocytes containing condensed sperm, while group II had a significantly higher number (53 %) of unfertilized oocytes containing condensed sperm (P < 0.05). CONCLUSION: SDF had a negative effect on the rate of fertilization in matured in vitro GV oocytes and could lead to an increase in the percentage of undecondensed sperm in IVM oocytes from stimulated cycles.

Evaluation of Epidermal Neural Crest Stem Cells in Organotypic Spinal Cord Slice Culture Platform.

Among various strategies employed for spinal cord injury, stem cell therapy is a potential treatment. So far, a variety of stem cells have been evaluated in animal models and humans with spinal cord injury, and epidermal neural crest stem cells represent one of the attractive types in this area. Although these multipotent stem cells have been assessed in several spinal cord injury models by independent laboratories, extensive work remains to be done to ascertain whether these cells can safely improve the outcome following human spinal cord injury. Among the models that closely mimic human spinal cord injury, the in vitro model of injury in organotypic spinal cord slice culture has been identified as one of the faithful platforms for injury-related investigations. In this study, green fluorescent protein-expressing stem cells were grafted into injured organotypic spinal cord slice culture and their survival was examined by confocal microscope seven days after transplantation. Data obtained from this preliminary study showed that these stem cells can survive on top of the surface of injured slices, as observed on day seven following their transplantation. This result revealed that this in vitro model of injury can be considered as a suitable context for further evaluation of epidermal neural crest stem cells before their application in large animals.

Validation of Persian version of WHOQOL-HIV BREF questionnaire in Islamic Republic of Iran.

The aim of this cross-sectional study was to validate the first Persian version of the WHOQOL-HIV BREF questionnaire. The study sample comprised 61 patients regularly attending the outpatient infectious disease clinic consultation centre for patients with behavioural disorders in 2013-2014. The internal consistency, content related validity and reliability of WHOQOL-HIV BREF were evaluated. Content validity was quantified using the content validity ratio (CVR) according the to Lawshe formula. CVR > 0.51 and mean judgment > 2 were significant at P = 0.05. The Cronbach alpha score was > 0.7 for each domain and = 0.87 for the whole scale, indicating good reliability. Item-to-total correlation coefficient between each item and its respective domain was 0.39-0.87. The correlation between each domain and overall QOL was excellent. This study demonstrates that the Persian version of WHOQOL-HIV BREF is a valid and reliable tool for evaluation of QOL in HIV-infected patients.

Oligodendrocyte progenitor cells differentiation of nuclear transferred mouse embryonic stem cells.

Central nervous system (CNS) injuries cause to variable disorders in people around the world without any decisive treatment. Use of embryonic stem cells (ESCs) would be helpful in repairing of neural system damages. Somatic cell nuclear transfer (SCNT) is a way for implanting ESCs with lowest possible rejection. In the present study, mouse nuclear transfers ESCs (ntESCs) ability in differentiation to oligodendrocyte progenitor cells (OPCs) was investigated by morphological study, RT—PCR and flow cytometry analysis. Bi—polar and tri—polar, OPCs were observed in stem cells cultured in differentiation medium after four weeks. Result of gene expression analysis demonstrated that differentiated stem cells were expressed most important OPCs related gene markers after differentiation period. Moreover, flow cytometry analysis carried out to confirm other results that showed differentiated stem cells significantly expressed NG2 and O4 as critical OPC surface markers. Taken together, it seems that mouse ntESCs showed highly potential for OPC differentiation and could be an appropriate candidate for stem cell therapies.

Celecoxib as an Adjuvant to Fluvoxamine in Moderate to Severe Obsessive-compulsive Disorder: A Double-blind, Placebo-controlled, Randomized Trial.

INTRODUCTION: A growing body of evidence implicates inflammatory cascades in the pathophysiology of obsessive-compulsive disorder (OCD), making this pathway a target for development of novel treatments. METHODS: 50 outpatients with moderate to severe OCD participated in the trial, and underwent 10 weeks of treatment with either celecoxib (200 mg twice daily) or placebo as an adjuvant to fluvoxamine. Participants were investigated using Yale-Brown Obsessive Compulsive Scale (Y-BOCS). The main outcome measure was to assess the efficacy of celecoxib in improving the OCD symptoms. RESULTS: General linear model repeated measures demonstrated significant effect for time × treatment interaction on the Y-BOCS total scores [F (1.38, 66.34)=6.91, p=0.005]. Kaplan-Meier estimation with log-rank test demonstrated significantly more rapid response in the celecoxib group than the placebo group (p<0.001). There was no significant difference in adverse event frequencies between the groups. DISCUSSION: The results of the current study suggest that celecoxib could be a tolerable and effective adjunctive treatment for more rapid and more satisfying improvements in OCD symptoms.

Patients with psoriasis are at a higher risk of developing nonalcoholic fatty liver disease.

BACKGROUND: Psoriasis is a chronic, immune-mediated inflammatory skin disease with many extracutaneous manifestations. Several recent studies have indicated an increased prevalence of nonalcoholic fatty liver disease (NAFLD) among patients with psoriasis. In the present study, we investigated the prevalence of NAFLD in a population of Iranian patients with psoriasis. METHODS: NAFLD was assessed and graded using ultrasonography in 123 patients with psoriasis and 123 healthy controls (HCs) matched by age, sex and body mass index (BMI). RESULTS: The prevalence of NAFLD was significantly higher in the psoriatic group compared with the HC group (65.6% vs. 35%, P < 0.01, OR = 3.53). Median NAFLD grade was significantly greater in patients with psoriasis compared with HCs (grade 2 vs. grade 1, P < 0.01). In patients with psoriasis, NAFLD was associated with a higher frequency of hypertension (16.5%), abnormal liver function test (LFT) results (16.4%) and metabolic syndrome (46.6%). Moreover, patients with psoriasis and NAFLD tended to have significantly higher values for BMI, waist circumference (WC), Psoriasis Activity and Severity Index (PASI), and levels of serum triglyceride, cholesterol, low-density lipoprotein and fasting blood sugar (FBS). Multivariate logistic regression revealed that WC, PASI, LFT abnormalities, hypertension and cigarette smoking were independent predictors of NAFLD grade. CONCLUSIONS: Our findings warrant a detailed assessment of metabolic comorbidities including NAFLD in patients with a primary diagnosis of psoriasis. Lifestyle modifications, including weight loss and smoking cessation, may be necessary for patients with psoriasis to decrease the risk and severity of NAFLD.

[Significant association between nonsyndromic cleft lip with or without cleft palate and IRF6rs2235371 polymorphism in Iranian familiar population].

According to previous studies the IRF6rs2235371 polymorphism is a risk factor for NSCL/P in different populations. However our recent study revealed no correlation between IRF6rs642961 and NSCL/P in our population. In the present study we have investigated the relationship between IRF6rs2235371 and NSCL/P in same group to determine whether IRF6rs2235371 is a risk factor in our population as well. We analyzed the IRF6rs2235371 genotype in a subset of the Iranian population using the Polymerase Chain Reaction technique. The PCR products were digested with DpnII. Chi-square test was applied to analyze the obtained result. The patients were supplied by the Cleft Lip and Palate Clinic of the Isfahan University of Medical Science. A clinician ascertained the non-syndromic status of all patients and that no clefting drugs, ethanol or smoking were abused during pregnancy. The control group was selected from unaffected subjects with no history of NSCL/P in their families. 107 patients from 107 Iranian unrelated families and 100 controls were screened. There was a significant association between the IRF6rs2235371 genotype sand an increased NSCL/P risk. Our data indicates that the IRF6rs2235371 variation can increase the risk of NSCL/P in the Iranian population. This result is in contrast with the results of our recent study on the correlation between the IRF6rs642961 polymorphism and NSCL/P in the same group.

Chemical composition and hepatoprotective activity of ethanolic root extract of Taraxacum Syriacum Boiss against acetaminophen intoxication in rats.

AIM: In the present study, the role of ethanol extract of root of Taraxacum Syriacum Boiss (TSBE) against hepatotoxicity caused by acetaminophen (APAP) was studied. METHODS: The chemical composition of roots of Taraxacum Syriacum Boiss was analyzed by SPME-GC/MS method. Hepatocellular injuries induced by acetaminophen (APAP) were assessed by liver histology, serum aminotransferase activities, antioxidant enzymes activity and lipid peroxidation in liver tissue. RESULTS: TSBE was observed to exhibit hepatoprotective effect as demonstrated by significant decrease in serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), and alkaline phosphatase (ALP) concentration, and by preventing liver histopathologic changes in rats with APAP hepatotoxicity. Administration of APAP, significantly increased, lactate dehydrogenase (LDH) and catalase (CAT) activity in liver tissue and pretreatment with TSBE returned these parameters to control group, moreover TSBE reduces APAP-induced hepatic Glutathione (GSH) depletion. Carvacrol (6.7 %) was the main polyphenolic compound of plant sample. Our results demonstrated hepatoprotective activity of TSBE in rat in vivo. CONCLUSIONS: We believe that the mechanism by which the extract was able to protect the liver from the oxidative stress generated by APAP is due to its antioxidant activity. These phenolic compounds of the extract act as antioxidants and free radical scavengers and reduce or inhibit the oxidative stress induced by APAP administration (Tab. 3, Fig. 3, Ref. 39).

The decrease in NKG2D+ Natural Killer cells in peripheral blood of patients with metastatic colorectal cancer.

BACKGROUND: Natural killer (NK) cells play important roles in the immune defense against tumors such as colorectal cancer. In humans, NKG2D is an activating immune receptor constitutively expressed in most cytotoxic lymphocytes including NK and CD8+ T cells. In this study, the expression of NKG2D molecule was investigated in peripheral blood NK cells from colorectal cancer patients and compared with healthy subjects. METHODS: We studied 21 non-metastatic (low-grade), 17 non-metastatic (high-grade), 16 metastatic colorectal cancer patients, and 24 healthy controls. Peripheral blood samples were obtained to isolate peripheral blood mononuclear cells (PBMCs) and the percentage of peripheral blood NKG2D+CD3-CD56+ NK cells was analyzed by flow cytometry. The expression of NKG2D at mRNA level was also measured by real-time PCR in both, patients and control subjects. RESULTS: The results showed a significant reduction in the percentage of NKG2D+NK cells as well as NKG2D mRNA expression in peripheral blood of metastatic colon cancer patients. CONCLUSION: This result suggests that decreased expression of activating NKG2D receptor in metastatic colorectal cancer might compromise NK cell function and allow tumor to evade immunity (Tab. 3, Fig. 4, Ref. 33).

Correlation between serum 25(OH)D values and lupus disease activity: an original article and a systematic review with meta-analysis focusing on serum VitD confounders.

Notwithstanding that several original studies and some systematic reviews have been undertaken on the subject "correlation between serum values of vitamin D (VitD) and lupus disease activity," there is still no consensus on the importance of sectional measurement of serum VitD in the prediction of disease activity and important confounders in estimation of serum VitD. Medline, Web of Knowledge, and Scopus databases were searched from 1995 to 2013. The following medical subject heading (MeSH) terms and/or text words were used: "Vitamin D" OR "25OHD" OR "25(OH)D" combined with "systemic lupus erythematosus" OR "lupus" OR "SLE." References cited in the identified articles were also manually searched. Human studies in any language were included. Original research on this topic was also carried out on 82 lupus patients, considering important VitD confounders according to our systematic review and we included them in the meta-analysis. A total of 35 studies were registered for this study. Only 11 of these pointed to this correlation by Pearson test. The pooled Pearson correlation (r) of associations between disease activity and VitD was -0.365 (95% CI: -0.536, -0.165) with significant heterogeneity (p = 0.001 I (2 )= 93%). Sensitivity analysis resulted in no significant differences. The most important adjustable confounders considered by researchers were drugs, especially hydroxychloroquine, prednisolone and supplementary VitD, body mass index (BMI) and proteinuria or renal function. Only proteinuria was reported to influence VitD concentration strongly. BMI was another probable influencing factor. Our original research presented no correlation between VitD and SLEDAI (p = 0.68, r s = 0.003). This meta-analysis demonstrated that most of the studies on the relationship between VitD and lupus disease activity that found no correlation did not present the details of the statistics. However, analyzing 11 studies, most of which found a reverse correlation and reported it in detail, and our study found a weak reverse correlation between those two items. Systematic review of confounders showed that BMI, medications and kidney involvement were the most remarkable ones reported by researchers.

Evaluation of protective effect of propolis on parotid salivary glands in gamma-irradiated rats.

OBJECTIVE AND BACKGROUND: One of the most significant side effects of radiotherapy for head and neck cancers is xerostomia as a result of salivary gland damage. Considering pharmaco- logical effects of propolis, we evaluated its protective effect on salivary glands subjected to radiotherapy of head and neck cancer patients. MATERIALS AND METHODS: Twenty-one male albino rats (8-11 W, 190 ± 5 gm) were divided into three groups of seven animals. Scintigraphy was performed in all the groups. Then groups 1 (S) and 2 (SR) received normal saline injections and group 3 (PR) received propolis injection over 3 days. After that groups 2 and 3 were exposed to gamma radiation and all the rats underwent scintigraphic assessment on third day and 70th day after irradiation. The lips and tongues of rats in groups 2 and 3 were examined for mucositis daily in first 10 days. At the end, the parotid glands of all rats were examined histologically. RESULTS: Scintigraphy results of third and 70th day after irradiation showed statistically significant differences between PR and SR as well as SR and S. However, there was no significant difference between the PR and S groups. Histopathologic assessment demonstrated significant difference between SR, PR and S. CONCLUSION: These results suggest that propolis has protective effects on salivary gland function in animal models whilst it did not prevent radiation-induced histologic changes in tissues. Further investigations are needed to elucidate mechanisms of propolis actions. Clinical significance: Regarding to the results of this study, propolis may be useful in reduction xerostomia due to radiation to salivary glands and may be helpful for head and neck cancer patients.