Effects of Low-dose Gamma Radiation on Expression of Apoptotic Genes in Rat Peripheral Blood Lymphocyte

Role of TLR4 signaling pathway in the mitigation of damaged lung by low-dose gamma irradiation

Organisms frequently suffer negative effects from large doses of ionizing radiation. However, radiation is not as hazardous at lower doses as was once believed. The current study aims to evaluate the possible radio-adaptive effect induced by low-dose radiation (LDR) in modulating high-dose radiation (HDR) and N-nitrosodiethylamine (NDEA)-induced lung injury in male albino rats. Sixty-four male rats were randomly divided into four groups: Group 1 (control): normal rats; Group 2 (D): rats given NDEA in drinking water; Group 3 (DR): rats administered with NDEA then exposed to fractionated HDR; and Group 4 (DRL): rats administered with NDEA then exposed to LDR + HDR. In the next stage, malondialdehyde (MDA), glutathione reduced (GSH), catalase (CAT), and superoxide dismutase (SOD) levels in the lung tissues were measured. Furthermore, the enzyme-linked immunoassay analysis technique was performed to assess the Toll-like receptor 4 (TLR4), interleukin-1 receptor-associated kinase 4 (IRAK4), and mitogen-activated protein kinases (MAPK) expression levels. Histopathological and DNA fragmentation analyses in lung tissue, in addition to hematological and apoptosis analyses of the blood samples, were also conducted. Results demonstrated a significant increase in antioxidant defense and a reduction in MDA levels were observed in LDR-treated animals compared to the D and DR groups. Additionally, exposure to LDR decreased TLR4, IRAK4, and MAPK levels, decreased apoptosis, and restored all the alterations in the histopathological, hematological parameters, and DNA fragmentation, indicating its protective effects on the lung when compared with untreated rats. Taken together, LDR shows protective action against the negative effects of subsequent HDR and NDEA. This impact may be attributable to the adaptive response induced by LDR, which decreases DNA damage in lung tissue and activates the antioxidative, antiapoptotic, and anti-inflammatory systems in the affected animals, enabling them to withstand the following HDR exposure.

Diagnostic value of routine dental radiographs for predicting the mandibular canal localization validated by cone-beam computed tomogram measurements

OBJECTIVES

To test the hypothesis that routine dental radiographs can be used to draw conclusions regarding the mandibular canal (MC) localization. MATERIAL AND METHODS: A total of 108 radiographs (36 orthopantomograms [OPTs], 36 lateral cephalograms [LCs], and 36 cone-beam computed tomograms [CBCTs]) of 36 patients were analyzed. Statistical analysis included all cephalometric parameters obtained by OPTs, LCs, and CBCTs. Potential influencing parameters were calculated using linear and logistic regression with a backward removal algorithm. For predictability of MC localization, parameters were correlated using Pearson's correlation.

RESULTS

The MC ran along the lingual half (n = 24) twice as often as in the buccal half (n = 12) in the population studied. The position was always symmetrical contralaterally. No sex-specific influence was observed (p = .34). Lingual and buccal MC courses were statistically significantly correlated to increased and decreased jaw angles (LC/OPT), respectively (p = .003; r = -.48/p = .010; r = -.42). An increased jaw angle was significantly correlated with a more cranial MC position (p = .013; r = -.41); a deep and distal bite position was significantly correlated with a caudal and buccal MC position (p = .004; r = -.47/p = .001; r = .57). Moreover, an increase of 1 point in the Hasund score predicted an increased probability of a buccal MC position by 18.6%. The jaw angle analyzed in OPT and LC images were positively correlated (r = .89, p < .001).

CONCLUSIONS

Routine dental radiographs provide informative guidance on the location of the MC in the vertical and transverse levels. This finding could be used in the initial consultation and treatment planning to consider more invasive diagnostic methods further down the line.