Comparative analysis of chemical profiles, antioxidant, antibacterial, and anticancer effects of essential oils of two Thymus species from Montenegro

The essential oils of Thymus vulgaris (TVEO) and Thymus serpyllum (TSEO) show different biological activities. The aim of the study was to evaluate the biological activities of TVEO and TSEO from Montenegro. The main components of TVEO were p-cymene (29.52%), thymol (22.8%) and linalool (4.73%) while the main components of TSEO were p-cymene (19.04%), geraniol (11,09%), linalool (9.16%), geranyl acetate (6.49%) and borneol (5.24%). Antioxidant activity determined via DPPH for TVEO was 4.49 and FRAP 1130.27, while for TSEO it was estimated that DPPH was 4.88 μL/mL and FRAP was 701.25 μmol FRAP/L. Both essential oils were active against all tested bacteria, with the highest level of sensitivity of E. coli with MIC of 1.5625 μL/mL. Essential oils showed strong cytotoxic effects on human cancer cell lines, with IC50 values ranging from 0.20 to 0.24 μL/mL for TVEO and from 0.32 to 0.49 μL/mL for TSEO. TVEO caused apoptosis in cervical adenocarcinoma HeLa cells through activation of caspase-3 and caspase-8, while TSEO caused apoptosis through caspase-3. EOs decreased levels of oxidative stress in normal MRC-5 cells. HeLa cells treated with TVEO had reduced MMP2 expression levels, while cells treated with TSEO had lowered MMP2 and MMP9 levels. The treatment of HeLa cells with TVEO increased the levels of miR-16 and miR-34a, indicating potential tumor-suppressive properties. Our findings suggest that Thymus essential oils may be considered as good candidates for further investigation as cancer-chemopreventive and cancer-therapeutic agents.

MicroRNA networks linked with BRCA1/2, PTEN, and common genes for Alzheimer's disease and breast cancer share highly enriched pathways that may unravel targets for the AD/BC comorbidity treatment

MicroRNAs (miRNAs) are involved in the regulation of various cellular processes including pathological conditions. MiRNA networks have been extensively researched in age-related degenerative diseases, such as cancer, Alzheimer's disease (AD), and heart failure. Thus, miRNA has been studied from different approaches, in vivo, in vitro, and in silico including miRNA networks. Networks linking diverse biomedical entities unveil information not readily observable by other means. This work focuses on biological networks related to Breast cancer susceptibility 1 (BRCA1) in AD and breast cancer (BC). Using various bioinformatics approaches, we identified subnetworks common to AD and BC that suggest they are linked. According to our results, miR-107 was identified as a potentially good candidate for both AD and BC treatment (targeting BRCA1/2 and PTEN in both diseases), accompanied by miR-146a and miR-17. The analysis also confirmed the involvement of the miR-17-92 cluster, and miR-124-3p, and highlighted the importance of poorly researched miRNAs such as mir-6785 mir-6127, mir-6870, or miR-8485. After filtering the in silico analysis results, we found 49 miRNA molecules that modulate the expression of at least five genes common to both BC and AD. Those 49 miRNAs regulate the expression of 122 genes in AD and 93 genes in BC, from which 26 genes are common genes for AD and BC involved in neuron differentiation and genesis, cell differentiation and migration, regulation of cell cycle, and cancer development. Additionally, the highly enriched pathway was associated with diabetic complications, pointing out possible interplay among molecules underlying BC, AD, and diabetes pathology.

Melatonin Action in Type 2 Diabetic Parotid Gland and Dental Pulp: In Vitro and Bioinformatic Findings

Type 2 diabetes mellitus (T2DM) is associated with functional deterioration of the salivary gland and dental pulp, related to oxidative stress. The aim was to integrate experimental and bioinformatic findings to analyze the cellular mechanism of melatonin (MEL) action in the human parotid gland and dental pulp in diabetes. Human parotid gland tissue was obtained from 16 non-diabetic and 16 diabetic participants, as well as human dental pulp from 15 non-diabetic and 15 diabetic participants. In human non-diabetic and diabetic parotid gland cells (hPGCs) as well as in dental pulp cells (hDPCs), cultured in hyper- and normoglycemic conditions, glial cell line-derived neurotrophic factor (GDNF), MEL, inducible nitric oxide synthase (iNOS) protein expression, and superoxide dismutase (SOD) activity were measured by enzyme-linked immunosorbent assay (ELISA) and spectrophotometrically. Bioinformatic analysis was performed using ShinyGO (v.0.75) application. Diabetic participants had increased GDNF and decreased MEL in parotid (p < 0.01) and dental pulp (p < 0.05) tissues, associated with increased iNOS and SOD activity. Normoglycemic hDPCs and non-diabetic hPGCs treated with 0.1 mM MEL had increased GDNF (p < 0.05), while hyperglycemic hDPCs treated with 1 mM MEL showed a decrease in up-regulated GDNF (p < 0.05). Enrichment analyses showed interference with stress and ATF/CREB signaling. MEL induced the stress-protective mechanism in hyperglycemic hDPCs and diabetic hPGCs, suggesting MEL could be beneficial for diabetes-associated disturbances in oral tissues.

Clinically informative microRNAs for SARS-CoV-2 infection

COVID-19 is a viral respiratory infection induced by the newly discovered coronavirus SARS-CoV-2. miRNA is an example of a strong and direct regulator of a gene's transcriptional activity. The interaction between miRNAs and their target molecules is responsible for homeostasis. Virus-derived and host-derived miRNAs are involved in the activity of hiding from immune system cells, inducing the inflammatory reaction through interplay with associated genes, during SARS-COV-2 infection. Interest in miRNAs has raised the comprehension of the machinery and pathophysiology of SARS-COV-2 infection. In this review, the effects and biological roles of miRNAs on SARS-CoV-2 pathogenicity and life cycle are described. The therapeutic potential of miRNAs against SARS-CoV-2 infection are also mentioned.

Association of polymorphisms in TGFB1, XRCC1, XRCC3 genes and CD8 T-lymphocyte apoptosis with adverse effect of radiotherapy for prostate cancer

The genetic background of each person might affect the severity of radiotherapy (RT)-induced normal tissue toxicity. The aim of study was to evaluate the influence of TGFB1 C-509T and Leu10Pro, XRCC1 Arg280His and XRCC3 Thr241Met polymorphisms as well as the level of radiation-induced CD8 T-lymphocyte apoptosis (RILA) on adverse effects of RT for prostate cancer (PCa). The study included 88 patients with localized or locally advanced PCa who were treated with RT. The polymorphisms were determined by PCR-RFLP analysis on DNA from peripheral blood mononuclear cells. RILA values were measured by flow cytometry. We found that CT genotype of TGFB1 C-509T could be protective biomarker for acute genitourinary (GU) and gastrointestinal (GI) radiotoxicity, while Thr variant of XRCC3 Thr241Met could predict the risk for acute GU radiotoxicity. Correlation between RILA values and toxicity was not detected. Univariate logistic regression analysis showed that Gleason score and risk group were risk factors for late GU, while for late GI radiotoxicity it was diabetes mellitus type 2. However, in multivariate model those were not proven to be significant and independent risk factors. Identification of assays combination predicting individual radiosensitivity is a crucial step towards personalized RT approach.

Dual function miR-205 is positively associated with ER and negatively with five-year survival in breast cancer patients

BACKGROUND

Precise molecular characterization of breast cancer, especially triple negative (TNBC) as the most lethal subtype, is needed to stratify patients for the individual treatment approach. MicroRNA-205 (miR-205) has tumor-suppressive and oncogenic functions across different cancers. Therefore, miR-205 might have a different role in TNBC and estrogen receptor (ER) positive BC. Our aim was to investigate how miR-205 expression is associated with ER/progesteron receptor status, clinical parameters, pathohistological characteristics of BC, and survival of patients METHODS: We determined miR-205 relative expressions in 73 primary breast tumors (50 TNBC and 23 ER+) by quantitative Real-time polymerase chain reaction (qPCR) and compared it to clinicopathological characteristics and outcome.

RESULTS

The highest levels of miR-205 were in the ER+ /PR+ group, and the lowest in the TNBC group (p = 0.009). Significantly higher levels of miR-205 were also observed in the ER+ compared with the ER-negative group, regardless of the PR status (p = 0.002). Low miR-205 expression level was associated with prognostic stage III in TNBC samples (p = 0.049). Patients who received adjuvant chemotherapy had significantly lower levels of miR-205 (p = 0.016). Patients who received hormone therapy had significantly higher levels of miR-205 (p = 0.007). The low-miR-205 patients had significantly higher 5-year survival rates (p = 0.041).

CONCLUSION

The expression of miR-205 in BC is subtype-specific and high expression is associated with the ER+ tumors. The miR-205 expression might be a useful marker of TNBC progression. High miR-205 expression had a detrimental effect on BC patient outcome. Our results indicate that miR-205 might be utilized in clinical practice as a biomarker and an adjunct parameter for the selection of the most effective therapeutic modality.

Clinical Perspectives of Non-Coding RNA in Oral Inflammatory Diseases and Neuropathic Pain: A Narrative Review

Non-coding RNAs (ncRNAs) represent a research hotspot by playing a key role in epigenetic and transcriptional regulation of diverse biological functions and due to their involvement in different diseases, including oral inflammatory diseases. Based on ncRNAs’ suitability for salivary biomarkers and their involvement in neuropathic pain and tissue regeneration signaling pathways, the present narrative review aims to highlight the potential clinical applications of ncRNAs in oral inflammatory diseases, with an emphasis on salivary diagnostics, regenerative dentistry, and precision medicine for neuropathic orofacial pain.

Association between microRNAs 10b/21/34a and acute toxicity in glioblastoma patients treated with radiotherapy and temozolomide

A personalized approach to chemoradiation is important in reducing its potential side effects and identifying a group of patients prone to toxicity. MicroRNAs have been shown to have a predictive potential for radiotoxicity. The goal of the study was to test if levels of miRNA in peripheral blood mononuclear cells of glioblastoma patients are associated with toxicity and to identify the peak time point for toxicity. MicroRNA-10b/21/34a levels were measured in 43 patients with and without toxicity, at baseline, at the 15th, and at the 30th fraction by Real-Time quantitative Polymerase Chain Reaction. MicroRNA-10b/21 levels increased with toxicity grade (p = 0.014; p = 0.013); miR-21/34a levels were significantly different between patients with and without toxicity at the 15th fraction (p = 0.030; p = 0.045), while miR-34a levels significantly changed during treatment (p < 0.001). All three miRNAs showed a significantly high positive correlation with one another. MiR-34a might be considered as a predictive factor for toxicity due to its changes during treatment, and differences between the groups with and without toxicity; miR-10b might be used to predict toxicity; miR-10b/21 might be used for predicting the grade of toxicity in GB patients.

Antitumor activity, DNA and BSA interactions of novel copper(II) complexes with 3,4-dihydro-2(1H)-quinoxalinones

In order to discover new therapeutically active agents a series of novel copper(II) complexes with 3,4-dihydro-2(1H)-quinoxalinones were synthesized. All complexes were characterized by IR and EPR spectroscopic techniques and examined for their cytotoxic effect on human cancer cell lines HeLa, LS174, A549 and normal fibroblasts (MRC-5). For further examination of the cytotoxic mechanisms of novel complexes, three of them were chosen for analysing their effects on the distribution of HeLa cells in the cell cycle phases. The results of the flow cytometry analysis suggest that tested complexes lead to time-dependent accumulation of the cells in S and G2/M phases. The strongest accumulation effect showed complex 2d after 48 h of incubation. Competitive experiments with ethidium bromide (EB) indicated that tested compound 2d have affinity to displace EB from the EB-DNA complex through intercalation. Also, the binding parameters values for 2d-BSA complex showed that a reversible 2d-BSA complex is formed and ligand 2d can be stored and carried by BSA.

MicroRNAs in prostate cancer following radiotherapy: Towards predicting response to radiation treatment

Prostate cancer (PCa) is the second most frequently diagnosed male cancer worldwide. Early diagnosis of PCa, response to therapy and prognosis still represent a challenge. Nearly 60% of PCa patients undergo radiation therapy (RT) which might cause side effects. In spite of numerous researches in this field, predictive biomarkers for radiation toxicity are still not elucidated. MicroRNAs as posttranscriptional regulators of gene expression are shown to be changed during and after irradiation. Manipulation with miRNA levels might be used to modulate response to RT-to reverse radioresistance-to induce radiosensitivity, or if needed, to reduce sensitivity to treatment to avoid side effects. In this review we have listed and described miRNAs involved in response to RT in PCa, and highlighted potential candidates for future biological tests predicting radiation response to RT, with the special focus on side effects of RT. Individual radiation response is a result of the interactions between physical characteristics of radiation treatment and biological background of each patient, and miRNA expression changes among others. According to described literature we concluded that let-7, miR-21, miR-34a, miR-146a, miR-155, and members of miR-17/92 cluster might be promising candidates for biological tests predicting radiosensitivity of PCa patients undergoing radiation treatment, and as future agents for modulation of radiation response. Predictive miRNA panels, especially for acute and late side effects of RT can serve as a starting point for decisions for individualized RT planning. We believe that this review might be one step closer to understanding molecular mechanisms underlying individual radiation response of patients with PCa.

Breast Cancer Response to Therapy: Can microRNAs Lead the Way?

Breast cancer (BC) is a leading cause of death among women with malignant diseases. The selection of adequate therapies for highly invasive and metastatic BCs still represents a major challenge. Novel combinatorial therapeutic approaches are urgently required to enhance the efficiency of BC treatment. Recently, microRNAs (miRNAs) emerged as key regulators of the complex mechanisms that govern BC therapeutic resistance and susceptibility. In the present review we aim to critically examine how miRNAs influence BC response to therapies, or how to use miRNAs as a basis for new therapeutic approaches. We summarized recent findings in this rapidly evolving field, emphasizing the challenges still ahead for the successful implementation of miRNAs into BC treatment while providing insights for future BC management.The goal of this review was to propose miRNAs, that might simultaneously improve the efficacy of all four therapies that are the backbone of current BC management (radio-, chemo-, targeted, and hormone therapy). Among the described miRNAs, miR-21 and miR-16 emerged as the most promising, closely followed by miR-205, miR-451, miR-182, and miRNAs from the let-7 family. miR-21 inhibition might be the best choice for future improvement of invasive BC treatment.New therapeutic strategies of miRNA-based agents alongside current standard treatment modalities could greatly benefit BC patients. This review represents a guideline on how to navigate this elaborate puzzle.

Leukocyte- and platelet-rich fibrin as graft material improves microRNA-21 expression and decreases oxidative stress in the calvarial defects of diabetic rabbits

OBJECTIVE

Leukocyte- and platelet-rich fibrin (L-PRF) represents a natural, low-cost product which may promote tissue healing by mechanisms not fully elucidated. Diabetes mellitus (DM) disrupts bone healing by inducing inflammation and oxidative stress (OS), mechanisms regulated by microRNAs (miRs). The aim of the present study was to investigate the microRNA-21 (miR-21) involvement in diabetic bone regeneration using L-PRF alone or in combination with a standard grafting material.

DESIGN

After the induction of diabetes (alloxan 100 mg/kg), four cranial osteotomies were made in diabetic (n = 12) and non-diabetic (n = 12) rabbits: one was left empty and the remaining three were grafted with L-PRF, bovine hydroxyapatite (Bio-Oss^®) and L-PRF + Bio-Oss®. Two and eight weeks postoperatively, the samples were harvested for miR-21 expression (Real-time RT-PCR) and enzyme-linked immunosorbent assay analyses.

RESULTS

Diabetic rabbits showed decreased miR-21 and matrix metalloproteinase-9 (MMP-9) protein expression while increased malondialdehyde (MDA) levels two weeks postoperatively; however, there were no significant differences in miR-21 and MMP-9 levels between diabetic and non-diabetic rabbits in samples taken eight weeks postoperatively. Application of L-PRF and L-PRF + Bio-Oss^® improved miR-21 and MMP-9 and decreased MDA levels while Bio-Oss® alone enhanced superoxide dismutase (SOD) activity levels in diabetic rabbits.

CONCLUSION

L-PRF alone or in combination with bovine hydroxyapatite as bone graft could be beneficial in DM since it seems to improve inflammation-modulatory miR-21 expression and decreases oxidative stress.

Novel 1,3,4-thiadiazole-chalcone hybrids containing catechol moiety: synthesis, antioxidant activity, cytotoxicity and DNA interaction studies

Hybrid compounds that combine the 1,3,4-thiadiazole-containing catechol moiety with a chalcone motif were synthesized and examined for their antioxidant activity, cytotoxicity, and DNA-binding activity. A series of thirteen compounds showed strong antioxidant and cytotoxic effects on human acute promyelocytic leukemia HL-60 cells. Several compounds exerted good cytotoxic activities on cervical adenocarcinoma HeLa cells. The treatment of HeLa cells with IC₅₀ and double IC₅₀ concentrations of the compounds 5a, 5c, 5f, and 5m induced a statistically significant increase in the percentage of cells within a subG1 cell cycle phase. The examined compounds caused G2/M cell cycle arrest in HeLa cells. Each of these compounds triggered apoptosis in HeLa cells through activation of caspase-3, the main effector caspase, caspase-8, which is involved in the extrinsic apoptotic pathway, and caspase-9, which is involved in the intrinsic apoptotic pathway. All of the examined compounds decreased the expression levels of MMP2 in HeLa cells and levels of protumorigenic miR-133b. Compounds 5a and 5m lowered the expression level of oncogenic miR-21 in HeLa cells. In addition, compounds 5a, 5f, and 5m decreased the expression levels of oncogenic miR-155 while the treatment of HeLa cells with compounds 5a, 5c, and 5f increased expression of tumor-suppressive miR-206. Observed effects of these compounds on expression levels of four examined miRNAs suggest their prominent cancer-suppressive activity. An investigation by absorption and fluorescence spectroscopy showed more efficient calf thymus DNA binding activity of the compound 5m in comparison to other tested compounds. Results of a pUC19 plasmid cleavage study and comet assay showed DNA damaging activities of compounds 5a and 5c.

Highly selective anthraquinone-chalcone hybrids as potential antileukemia agents

A series of 23 novel anthraquinone-chalcone hybrids containing amide function was synthesized and structurally characterized. Sixteen compounds exerted strong cytotoxic activities against K562, Jurkat and HL-60 leukemia cell lines and significantly lower cytotoxic effects against normal MRC-5 cells, indicating very high selectivity in their anticancer action. The compounds 6g, 6u and 6v activate apoptosis in K562 cells through the extrinsic and intrinsic apoptotic pathway. The compound 6e triggered apoptosis in K562 cells only through the extrinsic apoptotic pathway. Treatment of K562 cells with each of these four compounds caused decrease in the expression levels of MMP2, MMP9, and VEGF, suggesting their anti-invasive, antimetastatic and antiangiogenic properties. The compounds 6g and 6v downregulated expression levels of miR-155 in K562 cells, while compounds 6e and 6u upregulated miR-155 levels in treated cells, in comparison with control cells. The structure-based 3-D QSAR models for 6f, 6e, 6i and 6l describe pro-apoptotic activity against caspase-3.

MicroRNA-146a and microRNA-155 as novel crevicular fluid biomarkers for periodontitis in non-diabetic and type 2 diabetic patients

AIM

Recent studies point at the crucial role of epigenetic mechanisms in the development of multifactorial diseases such as periodontitis and diabetes mellitus (DM) type 2. In addition, circulatory microRNAs (miRs) have emerged as novel biomarkers for various diseases. Aim of this study was to investigate the levels of miR-146a and miR-155 and superoxide dismutase (SOD) activity in gingival crevicular fluid (GCF) of periodontitis patients with (CPDM) and without (CP) DM type 2 as well as in periodontally healthy, control groups (PHDM and PH, respectively).

MATERIAL AND METHODS

miR modulation was analysed using quantitative real-time PCR while SOD activity was measured spectrophotometrically.

RESULTS

The upregulation of miR-146a and miR-155 was observed in CP and CPDM patients' baseline, while the levels decreased after 6 weeks of the non-surgical therapy to the levels comparable to PH and PHDM, respectively. Expression levels of miRs positively correlated with SOD activity. Levels of miR-146a were higher in PHDM compared to PH patients. Multivariate analysis revealed that levels of miR-146a and miR-155 were significantly associated with periodontitis when adjusting for age and gender.

CONCLUSIONS

miR-146a and miR-155 may be considered as possible novel biomarkers for periodontitis in non-diabetic and type 2 diabetic patients.

Effect of neuropeptide Y on norepinephrine-induced constriction in the rabbit facial artery after carotid artery occlusion

BACKGROUND/AIM

Atherosclerotic-occlusive changes could be observed in orofacial branches of the external carotid artery. Atherosclerosis-induced ischemia caused alteration in production and release of endothelial factors. The aim of this study was to investigate the influence of carotid artery occlusion (10, 30 and 60 min) on vascular effects of norepinephrine (NOR) and neuropeptide Y (NPY) in the isolated glandular branch of the rabbit facial artery, the main feeding artery for the submandibular gland.

METHOD

Changes in isometric tension were recorded in organ bath studies with arterial rings, before and after carotid artery occlusion.

RESULTS

Concentration-dependent vasocontractile effect of NOR was significantly augmented after 30 and 60 min of carotid occlusion, but only in the rings with intact endothelium. Given alone, NPY showed no effect in isolated glandular branch of the rabbit facial artery, but enhanced NOR vasoconstriction in all the investigated rings. NOR vasocontractile effect enhancement in the presence of NPY was attenuated after 30 and 60 min of carotid occlusion. Also, enhancement of NOR vasoconstriction by NPY was significantly higher in endothelium-intact rings compared to endothelium-denuded rings obtained after 30 and 60 min of carotid occlusion.

CONCLUSION

The present investigation provides results of increased vasocontractile effect of NOR and decreased enhancing effect of NPY on NOR vasoconstriction in the rabbit facial artery after carotid occlusion that is related to altered endothelium function.

Higher miR-21 expression in invasive breast carcinomas is associated with positive estrogen and progesterone receptor status in patients from Serbia

MicroRNAs play essential role in breast carcinoma progression and invasion. Our principal goals were to assess clinicopathological and prognostic correlations of microRNA-21 (miR-21) expression levels in a group of 39 Serbian breast cancer patients with invasive lobular (ILC), ductal (IDC), or mixed (ILC-IDC) breast carcinomas and in order to discover the role of miR-21 in potential novel form of stratification of the patients with different estrogen receptor (ER) and progesterone receptor (PR) status. MiR-21 expression levels were measured by stem-loop real-time RT-PCR using TaqMan technology. ER, PR, human epidermal growth factor 2 receptor (Her-2), and proliferative index (Ki-67) were evaluated by immunohistochemistry. MiR-21 levels do not vary among ILC, IDC, and ILC-IDC subgroups. MiR-21 expression levels varied significantly in the age, tumor size, Ki-67, and different grade (p = 0.030, p = 0.036, p = 0.027 and p = 0.032, respectively) subgroups. ER+ and PR+ showed higher miR-21 levels than their negative receptor status paired groups ER- and PR- with p = 0.012 and p = 0.018, respectively. MiR-21 positively correlated with ER and PR status (p = 0.018, ρ = 0.379 and p = 0.034, ρ = 0.345, respectively). Our findings suggest that miR-21 emulates transitional form of expression and that the levels of expression might be useful for stratification of the patients with different receptor status with the purpose to seek for new therapy approaches especially for the patients with the lack of response to conventional endocrine therapy.

The difference in miR-21 expression levels between invasive and non-invasive breast cancers emphasizes its role in breast cancer invasion

MicroRNA-21 (miR-21) overexpression is characteristic for various types of tumors, but it is still unknown whether its expression levels differ between invasive and non-invasive breast carcinomas. The main goal of the study was to determine the difference in miR-21 expression among normal tissue, non-invasive, invasive with non-invasive component, and pure invasive breast cancer samples, to explain its potential role and significance in breast cancer invasiveness. The second goal was to propose miR-21 as molecular marker of breast cancer invasiveness and potential target for future anti-miR therapies for the prevention of invasion and metastasis. In order to reveal the role of miR-21 in breast cancer invasiveness, we measured miR-21 expression levels in 44 breast cancer and four normal samples by stem-loop real-time RT-PCR using TaqMan technology. Relative expression levels of miR-21 were significantly higher in invasive than in other groups (P=0.002) and significantly higher in invasive compared with invasive with non-invasive component group in histological (P=0.043) and nuclear grade 2 (P=0.036), estrogen-receptor-positive (ER+) (P=0.006), progesterone-receptor-positive (PR+) (P=0.008), ER+PR+ (P=0.007), and proliferation index (Ki-67)≤20% (P=0.036) tumors. Our findings suggest that miR-21 could be independent molecular marker of breast cancer invasiveness and potential target for future anti-miR therapies for the prevention of invasion and metastasis.

Contribution of activation products to occupational exposure following treatment using high-energy photons in radiotherapy

When high-energy photon beams are used for irradiation in radiotherapy, neutrons that are the result of photonuclear reactions create activation products that affect the occupational dose of radiotherapy staff. For the assessment of activation products in situ gamma spectroscopy was performed parallel to dose-rate measurements following irradiation, by using a high-energy photon beam from a linear accelerator Elekta Precise (Elekta, Stockholm, Sweden) used in radiotherapy. The major identified activation products were the following radioisotopes: (28)Al, (24)Na, (56)Mn, (54)Mn, (187)W, (64)Cu and (62)Cu. Based on the typical workload and dose-rate measurement, the assessed additional annual occupational dose ranged from 1.7 to 0.25 mSv. As the measured dose rate arising from the activation products rapidly decreases as a function of time, the assessed additional dose is negligible after 10 min following irradiation. To keep the occupational dose as low as reasonably achievable, it is recommended to delay entrance to the therapy room at least 2-4 min, when high-energy photons are used. This would reduce the effective dose by 30%.

Hepatobilijarna scintigrafija u proceni funkcije transplantirane jetre

The aim of the study is evaluation of hepatocellular function, as well as morphology and patency of the biliary three of the liver transplants by dynamic hepatobiliary scintigraphy. The study was performed in 10 controls and 10 patients after orthotopic transplantation (up to two years). Sixty minutes dynamic acquisition (1 frame/min) was performed with scintillation camera after injection of 360 MBq 99mTc-diethyl-IDA. Hepatobiliary scintigrams were analysed for morphology, and parenchymal and hepatobiliary TA curves were generated and analysed as regard to the time to maximal acitivity (Tmax) and the time to half of maximum acitivity (T1/2). Uptake of the radiopharmaceutical was slightly but not significantly delayed (Tmax=18.5+2.9 min) in comparison to the controls (Tmax=14.2+ 3.4min), while excretion was significantly prolonged (T1/2=59.5+ 12.1 min) than physiological (Tmax=34.2+4.1min). Intrahepatic bile flow was nonsignificantly prolonged (Tmax=31.3+3.7 min) in comparison to the controls (Tmax=25.7+ 3.5 min) while extrahepatic one is high significantly prolonged (T1/2=89.0+14.3 min) than physiological (T1/2 =45.0+ 7.2 min). Biliary phase of hepatobiliary scintigraphy showed increased accumulation of radiopharmaceutical in the left (n=1) or right (n=2) hepatic duct. Radionuclide methods are noninvasive, and apear to be sensitive and valuable for the monitoring of liver transplants.

[Indium 111-labeled antibodies in the detection of colorectal carcinoma]

The aim of the study is detection of the recurrences and metastases of colorectal carcinomas using (111)In labelled antibodies B72.3 in 14 patients. With tomography, we can access better distinction of tumour in comparison to other structures and estimation of its size. Other imaging methods (CT, US) have advantage in detection of liver metastases, while immunoscintigraphy is more specific for the assessment of malignant abdominal tumours and extrahepatic metastases. The first results point out that Oncoscint CR-103 can be useful in diagnosis of recurrences and metastases of colorectal carcinoma, viability assessment after radiotherapy and in the choice of the adequate surgical treatment in dependence of the spread of the disease.

[Implementation of the radiolabelled antibiotic in the detection of orthopedic infections]

The aim of the study is detection and evaluation of the orthopedic infections using 99mTc-ciprofloxacin, radiopharmaceutical supposed to distinguish inflammation from infection. There were 15 true positive findings, 9 true negative, and two were false positive, while 1 was false negative. Sensitivity was 94%, specificity 82%, positive predictive value 88%, negative predictive value 90% and accuracy 89%. According to our results, scintigraphy with 99mTc-ciprofloxacin is a useful method for detection and assessment of exact localization of orthopedic infections, which might be useful for (differential) diagnosis, surgical treatment in due time as well as monitoring of the treatment of conservative therapy.

[Liver hemangioma blood pool as a function of time]

Aim of the study was to determine the time needed for establishing maximal labelled red blood cell concentration in hemangioma by scintigraphic semiquantitative blood pool estimation as a function of time.

PATIENTS AND METHODS

Eleven patients (eight females and three males) with total number of fourteen liver hemangiomas have been examined. Nine of them had solitary lesions and remaininig two patients had two and three liver hemangiomas, respectively. All patients underwent blood pool scintigraphy 40, 60, 120 and 180 minutes after in vivo labelling of autologous red blood cells using 740 MBq of 99mTc. After correction for radioactive decay of 99mTc and back-ground correction blood pool indexes, as hemangioma/heart and liver/heart counting rate ratios, have been calculated.

RESULTS

Mean blood pool indexes obtained 40-180 minutes after in vivo red blood cell labelling did not differ significantly (p > 0.05) neither in hemangioma (0.84-0.86) nor in liver tissue (0.55-0.58). In every acquisition time hemangioma blood pool index was substantialy higher than that of liver tissue (p < 0.01).

CONCLUSION

The results of the study indicates that labelled red blood cells concentration reaches its plateau before 40th minute following in vivo labelling. The concentration difference between hemangioma and liver tissue also does not differ significantly after 40th minute of blood pool examination. In most patients blood pool scintigrams taken 60, 120 and 180 minutes following in vivo RBC labelling do not contribute to diagnostic value of the method.

[Radionuclide detection of Helicobacter pylori infection]

The aim is the assessment of the HP infection in stomach using breath test and comparison to other diagnostic methods, as well as following up the effect of therapy. In 83 patients with digestive discomfort rapid urease test, histology and breath test were performed, while in 25 patients with proven HP infection the effect of therapy was followed up using breath test and clinical findings. For rapid urease test and histology, samples were taken from antral mucosa. Breath test was performed after per oral administration of the capsule of 14C- urea (37 kBq) (Izotop, Hungary and Laboratory for radioactive isotopes, Vinca) which, in the presence of Helicobacter pylori breaks up to 14CO2 and NH3. Radioactivity was measured by beta counter in the exhaled air fasting and 30 minutes after ingestion of the capsule. According to our results, the rise of activity over 100% was considered positive. From 83 patients, 58 were breath test was positive, 24 negative and one equivocal. Fast urease test was in 54 positive, in 29 negative while histology was in 57 postitive and 26 negative. Findings of the breath and urease tests were in accordance in 93% patients while breath test and histology in 98% patients. During follow up of the therapeutic effects, breath test and clinical findings were in accordance in 98% patients. Breath test can be useful in diagnosis but is a method of choice in following up the patients after therapy for H. pylori infection, because it is non-invasive, fast and precise.

Effect of Cold Exposure on Serum DBH and Interscapular Brown Adipose Tissue MAO Activity in Hypothyroid T3- and T4-Treated Rats

As the indicators of sympathetic nervous system (SNS) function, the activity of serum dopamine-beta-hydroxylase (DBH) and interscapular brown adipose tissue (IBAT) monoamine oxidase (MAO) were examined in rats that were chemically thyroidectomized (TX), treated with thyroid hormones, and exposed to cold (4 degrees C). In TX animals, body temperature (bt) significantly decreased, and relative IBAT mass increased as compared with control, euthyroid animals, independent of the ambient temperature. The bt fall in TX cold-exposed animals was more severe, provoking hypothermia after 4 h. Under the same experimental conditions, the SNS function was enhanced as judged by the increased serum DBH and IBAT MAO activities. The treatment of TX animals with T(4) and T(3) re-established the temperature (bt was at the level of controls) and sympathetic homeostasis (DBH activity was at the level of controls) in animals maintained at room temperature but not in those kept under cold conditions. T(4) and T(3) did not affect IBAT MAO activity of TX rats: It remained significantly above the control values whether the animals were maintained at room temperature or exposed to cold. In conclusion, the IBAT of TX cold-exposed rats is incapable of responding to the enhanced thermogenic needs despite the increased SNS activity and thyroid hormone substitution.

Thyroxine and tri-iodothyronine differently affect uncoupling protein-1 content and antioxidant enzyme activities in rat interscapular brown adipose tissue

The activity of the antioxidant enzymes copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD) and catalase (CAT), as well as mitochondrial glycerol-3-phosphate dehydrogenase (mGPDH) activity, uncoupling protein-1 (UCP1) content, catecholamine degrading enzyme monoamine oxidase (MAO) activity and malonyl dialdehyde (MDA) concentration were studied in rat interscapular brown adipose tIssue (IBAT). Rats were treated with either thyroxine (T4) or tri-iodothyronine (T3) for five days and then exposed to cold (4 degrees C, 24 h) or housed at room temperature (22 degrees C). Under basal conditions, T3 treatment significantly increased UCP1 content and MnSOD activity whereas CuZnSOD, CAT and MAO activities were significantly decreased. Thyroxine treatment significantly decreased IBAT CAT activity while MDA levels markedly increased. Cold exposure induced a significant augmentation of UCP1 content and MnSOD and mGPDH activities only in animals that were rendered hyperthyroid by T4 treatment. In T3-treated animals acutely exposed to cold stress, MDA concentration, an indicator of lipid peroxidation, was significantly higher compared with that of T3-treated animals housed at room temperature. However, in T4-treated animals, MDA concentrations were markedly lower. These results show that T4 and T3 differently affect IBAT parameters studied not only under basal but also under cold-stimulated conditions.

Otkrivanje infekcija u abdomenu primenom radioobelezenog antibiotika

The aim of the study is detection of the abdominal infective foci using 99mTc-ciprofloxacin, radiopharmaceutical supposed to distuinguish inflammation from infection. Twenty one patient was investigated. There were 11 true positive findings, 7 true negative, two were false negative, while 1 was false positive. Sensitivity of the method was 79% and specificity 91%. According to our results, scintigraphy with infecton is a useful method for detection and assessment of exact localization of deep seated bacterial infections, which might be useful for (differential) diagnosis, surgical treatment in due time as well as monitoring of the treatment of conservative therapy.

[Evaluation of enterogastric reflux in relation to functional status of the gallbladder]

The aim of the study was estimation of the relation between the gallbladder (GB) motility function and the presence and quantity of enterogastric reflux (EGR). We investigated 172 patients with: physiological GB function (filling and emptying)(FGB), impaired GB function (prolonged filling and ejection fraction < 45%) and afunctional gallbladder (AGB)(without visualization). The study was performed during 90 min (1 f/min) after i.v. application of 185 MB 99mTc-dietil IDA. After 30 min. test meal was given while at the end stomach was marked. According to the parameters from time activity curves over stomach and hepatobiliary system, the index of ERG was calculated, while GB filling and ejection fraction were estimated from the GB time/activity curve. We can conclude that EGR occurs more frequently in the patients with afunctional GB in comparison to those with functional and decreased motor function. Also, EGR quantity is in correlation with the impairment of the GB function.

The activity of antioxidant enzymes and the content of uncoupling protein-1 in the brown adipose tissue of hypothyroid rats: comparison with effects of iopanoic acid

The activity of antioxidant enzymes, copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD) and catalase (CAT), as well as that of the mitochondrial FAD-dependent alpha-glycerophosphate dehydrogenase (alpha-GPD) in the rat interscapular brown adipose tissue (IBAT) were studied after the treatment with methimazole (MMI) for three weeks or with iopanoic acid (IOP) for five days. Besides, the mitochondrial concentration of uncoupling protein-1 (UCP-1) and the activity of catecholamine degrading enzyme monoamine oxidase (MAO) in the IBAT as well as the activity of the catecholamine synthesizing enzyme, dopamine beta-hydroxylase (DBH) in rat serum were examined. Judging by the significantly enhanced level of serum DBH, which is an index of sympathetic activity, and that of IBAT MAO, the increase in MnSOD and CAT activities in the IBAT of hypothyroid (MMI-treated) rats seems to be due to elevated activity of sympathetic nervous system (SNS). However, CuZnSOD activity is not affected by SNS. On the contrary, IOP, which is a potent inhibitor of T4 deiodination into T3 producing "local" hypothyroidism, did not change either SNS activity or activities of IBAT antioxidant enzyme. However, both treatments significantly decreased IBAT UCP-1 content and alpha-GPD activity suggesting that the optimal T3 concentration in the IBAT is necessary for maintaining basal levels of these key mitochondrial parameters.

[Study of blood flow in liver hemangiomas using radionuclide angiography]

Hepatic radionuclide angiography (HRA) is a recognised method of investigation of liver blood flow disorders caused by: diffuse and focal diseases of liver parenchyma or disorders of blood flow in extrahepatic liver vessels. Hepatic perfusion index (HPI) based on Sarper's slope method is significantly lower in patients with e.g. liver cirrhosis, malignant primary and metastatic liver diseases and portal vene thrombosis, but not in patients with benign focal liver leasions. Determined in liver as a whole, HPI is a sensitive indicator of the presence of malignant liver tumours, but is within normal range in patients with hepatic hemangioma. The aim of the study was to investigate characteristic of blood flow in hemangioma itself, separately from but in relation to the liver blood flow, using hepatic radionuclide angiography. We have examined 12 patients with liver hemangioma confirmed mainly by positive 99mTc-labeled red blood cell scintigraphy, which diagnostic specificity for liver hemangiomas is near 100%. 8/12 hemangiomas resulted in photopenic areas on angioscintigrams, indicating lower blood flow, and rest were isoactive to surrounding liver tissue. Regions of interest have been delineated around the photopenic areas (hemangiomas) and surrounding liver tissue. Time-activity curves have been generated and slope of the fitted hepatic artery and (portal) venous portions of the hemangioma and liver curves have been determined. Perfusion indexes of hemangioma (PIH) and liver (HPI) have been calculated from the slopes, expressing portal venous flow as a portion of entire blood flow to the region. In addition, times of arrival and transit of intravenous bolus of 99mTc-pertechnetate through the hemangioma and liver tissue have also been derived from time-activity curves. Slope of the venous portion of the hemangioma time-activity curve is significantly lower then that of the venous portion of the liver curve (p < 0.01). So that, perfusion index of hemangioma (PIH = 0.34 +/- 0.12 (mean +/- SD) is significantly lower then hepatic perfusion index (HPI = 0.57 +/- 0.08) (p < 0.05). Bearing in mind interference of superimposed liver activity with that of hemangioma, these results indicate that liver hemangiomas are dominantly if not exclusively irrigated by hepatic artery branches. There are no data regarding relation between arterial and venous blood flow in liver hemangiomas determined by HRA. Obtained results are in harmony with arteriography data which confirm slow arterial blood flow through hemangiomas. Portal venous inflow of some angiomatous liver lesions in infants and children, and arterio-portal shunting in hemangiomas have been rarely reported. Results of this study indicate that regional determination of perfusion index and other HRA parameters in patients with focal liver lesion enables differentiation between tissues with different intensity and pattern of blood flow. The method could be used in examination of vascularisation pattern of other focal liver lesions.

Aortal aneurysm as a cause of ileus

A 62-year-old patient presented with flatulence, abdominal distension and other symptoms of ileus. Roentgenographic finding found compression on duodenum. Blood pool scintigraphy ((99m)Tc erythrocytes) showed aortal aneurysm, while simultaneous gastric emptying study with liquid meal ((99m)Tc-S-colloid) showed dislocation of duodenum and compression from abdominal aortal aneurysm.

[Evaluation of enterogastric reflux using a modified scintigraphy method]

The aim of the study is evaluation of the clinical validity of the chosen and modified own model of the nuclear medicine method for the detection and quantification of enterogastric reflux (EGR), as well as evaluation of its clinical validity. The study was performed in 172 patients: with gastric and duodenal ulcer, after Billroth I and Billroth II gastrectomy, with gastroesophageal reflux, after cholecystectomy, with chronic cholecystitis and chronic duodenal disease. Acquisition was performed with gamma camera, during 90 minutes after intravenous application of 185 MBq 99m-Tc-Dietil IDA. Test meal was given in 30th minute, while gastric region was marked at the end of the study. On the basis of the radioactivity changes in the regions of the stomach and hepatobiliary system, presence of enterogastric reflux is determined and its index calculated. In all the groups of patients, values are significantly different from physiological. The most frequent occurrence and the largest quantity of reflux is present in patients after Billroth II gastrectomy with significantly different values from other groups of patients. The obtained results approve clinical value of the chosen and modified scintigraphy of EGR as a non-invasive and physiological method, which provides data about its presence and quantity.

Activities of antioxidant enzymes and monoamine oxidase-A in the rat interscapular brown adipose tissue: effects of insulin and 6-hydroxydopamine

The effects of different doses of insulin (INS) (0.4 or 4.0 IU/kg body mass, i.p., for 3 hr) and 6-hydroxydopamine (6-HDA) (100 mg/kg., i.p.) on the activities of antioxidant enzymes--copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), catalase (CAT) and catecholamine degrading enzyme monoamine oxidase (MAO-A)--in the rat interscapular brown adipose tissue (IBAT) were studied. In vivo 6-HDA administration, which induces the destruction of sympathetic nerves, markedly reduced IBAT CuZnSOD activity but did not change MnSOD and CAT activities. However, the low dose of INS, which did not induce hypoglycemia, significantly increased the activity of both IBAT mitochondrial enzymes (MnSOD and MAO-A) of control rats. This INS effect on MnSOD was abolished by 6-HDA. On the contrary, CuZnSOD activity was markedly reduced under the influence of INS in both control and 6-HDA-treated rats, whereas for the maintenance of the control level of this enzyme activity, the intact sympathetic nervous system (SNS) is necessary. INS, independent of the dose applied, did not affect CAT activity in control rats, whereas only low INS dose increased the activity of this enzyme in 6-HDA-treated rats. The results indicate that the stimulatory effect of INS on the IBAT mitochondrial enzymes studied is dose dependent and in the case of MnSOD is mediated by SNS. However, the depression in the activity of CuZnSOD is independent of the above-mentioned factors.

The effect of the rat-cyclophosphamide serum on the rat hematopoietic tissue recovery, previously damaged by cyclophosphamide or by gamma-irradiation

The effect of post-cyclophosphamide serum (post-CY serum) humoral activity in vivo, on the rat hematopoietic regeneration after damage either by cyclophosphamide (CY) or by gamma-irradiation was investigated. Three experimental groups of rats were studied. The first group was treated by a single high dose of CY (200 mg/kg), the second group was whole body irradiated by 6.5 Gy, and the third group was whole body irradiated by 3.5 Gy. Each group was subdivided into three subgroups. The first among subgroups received immediately after damage 0.5 cc post-CY serum, the second received 0.5 normal rat sera per animal. The third subgroup of rats was used as control. Post-CY sera were collected from the Wistar rats, 2.5 months old 48 hours after the treatment by high single dose by CY (300 mg/kg). Post-CY serum activity in comparison to normal serum activity was evaluated in vivo conditions. In order to take samples of peripheral blood, spleen and bone marrow, the animals were sacrificed 24 hours, 48 hours, 72 hours and seven days after treatment. The assessment of post-CY sera effect is accomplished by measuring of the proliferative capacity of splenic, as well as bone marrow cells, and by means of the RBC and WBC counts. The results obtained indicate substantial stimulative and proliferative activity of the post-CY sera, when compared to normal sera, particularly in the animals previously damaged with CY.

Susceptibility to proteolysis of thyroglobulin from rats and guinea-pigs treated with excess iodide

The effect of excess iodide on proteolysis of in vivo 125I-labelled thyroglobulin (Tg) from rats and guinea-pigs was investigated in vitro using preparations of thyroid lysosomes and exogenous proteases (Pronase). Lysosomes were obtained by centrifugation of pig thyroid homogenates. This lysosomal preparation induced maximal proteolysis of Tg at pH 3.6 to 4.6 and was stimulated by KCl. Treatment of rats with excess iodide for up to 28 days had no effect on the proteolysis of Tg by lysosomes or Pronase. Decreased resistance of Tg to proteolysis by lysosomes and pronase was observed in guinea-pigs treated with excess iodide for 3 days, whereas Tg from guinea-pigs treated for longer time periods had increased resistance to proteolysis. This difference in the susceptibility to proteolysis of Tg provides an explanation why long-term administration of excess iodide is goitrogenic in guinea-pigs but not in rats.

Abscopal effects of local fractionated X-irradiation of face and jaw region

The abscopal effects of high doses of X-irradiation, 6000 R given in 12 fractions locally on rat face and jaw region, upon the haematopoietic and lymphatic tissues, were studied. Haematological and pathophysiological studies were performed. Peripheral blood samples were taken after the 7th, 17th and 27th day during the course of the irradiation. 24 hours after the last irradiation the smears of femur bone-marrow were done. In the smears, the cells of erythrocyte and leukocyte series, as well as their mitotic index were determined. 24 hours after the irradiation the pieces of lymph nodes and salivary glands were taken for histological analysis. A significant depression of peripheral leukocyte counts was found in all observation intervals as well as the change in mitotic index of granulocyte series in bone marrow. No significant histological changes on the lymph nodes and salivary gland section were found 24 hours after the last irradiation.