Limbic-Auditory Interactions of Tinnitus: An Evaluation Using Diffusion Tensor Imaging.

OBJECTIVE: Tinnitus is defined as an imaginary subjective perception in the absence of an external sound. Convergent evidence proposes that tinnitus perception includes auditory, attentional and emotional components. The aim of this study was to investigate the thalamic, auditory and limbic interactions associated with tinnitus-related distress by Diffusion Tensor Imaging (DTI). METHODS: A total of 36 tinnitus patients, 20 healthy controls underwent an audiological examination, as well as a magnetic resonance imaging protocol including structural and DTI sequences. All participants completed the Tinnitus Handicap Inventory (THI) and Visual Analog Scales (VAS) related with tinnitus. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained for the auditory cortex (AC), inferior colliculus (IC), lateral lemniscus (LL), medial geniculate body (MGB), thalamic reticular nucleus (TRN), amygdala (AMG), hippocampus (HIP), parahippocampus (PHIP) and prefrontal cortex (PFC). RESULTS: In tinnitus patients the FA values of IC, MGB, TRN, AMG, HIP decreased and the ADC values of IC, MGB, TRN, AMG, PHIP increased significantly. The contralateral IC-LL and bilateral MGB FA values correlated negatively with hearing loss. A negative relation was found between the AMG-HIP FA values and THI and VAS scores. Bilateral ADC values of PHIP and PFC significantly correlated with the attention deficiency-VAS scores. CONCLUSION: In conclusion, this is the first DTI study to investigate the grey matter structures related to tinnitus perception and the significant correlation of FA and ADC with clinical parameters suggests that DTI can provide helpful information for tinnitus. Magnifying the microstructures in DTI can help evaluate the three faces of tinnitus nature: hearing, emotion and attention.

The effects of Teucrium polium on ionizing radiation-induced intestinal damage in rats.

BACKGROUND AND STUDY AIMS: Oxidative stress plays an important role in development of intestinal injury after abdomino-pelvic radiation therapy. Teucrium polium (TP) is a medicinal plant which has antioxidant and anti-inflammatory properties. The aim of this study was to investigate the effect of TP on radiation-induced intestinal oxidative damage in rats. MATERIALS AND METHODS: Group 1 (n = 8), the control group; Group 2 (n = 8), the RAD (radiation) group in which each rat received a single whole-body 800 cGy radiation performed with a LINAC ; Group 3 (n = 8), the RAD + TP group in which rats were exposed to radiation as in Group 2, followed by intragastric administration of 0.5 g/kg/daily TP extract for 7 consecutive days; and Group 4 (n = 8), the TP group, rats received only intragastric TP for 7 days. RESULTS: Radiation led to intestinal damage, which was accompanied by an increase in intestinal thiobarbituric-acid-reactive substances (TBARS) and myeloperoxidase (MPO) levels, and a decrease in reduced glutathione (GSH) levels. Although TP significantly decreased intestinal MPO levels and inflammation scores, it neither reverted intestinal TBARS and GSH levels nor ameliorated other histological parameters of the disease. CONCLUSIONS: Our results suggest that TP reduces inflammation but does not ameliorate the increased oxidative stress conditions in radiation-induced intestinal damage in rats.

Could honey have a place in colitis therapy? Effects of honey, prednisolone, and disulfiram on inflammation, nitric oxide, and free radical formation.

BACKGROUND/AIMS: The purpose of this study was to investigate the potential therapeutic roles of honey, prednisolone and disulfiram in an experimental model of inflammatory bowel disease. Another aspect of the study was to find out whether these substances have any effect on nitric oxide (NO) and free radical production. METHODS: After the induction of colitis with trinitrobenzene sulfonic acid in 64 male rats, physiological saline, honey, prednisolone and disulfiram enemas were applied to the rats once daily for 3 days (acute treatment groups) or 7 days (chronic treatment groups). Control groups received only saline enemas. Rats were killed on the 4th or 8th days and their colonic mucosal damage was quantitated using a scoring system. Acute and chronic inflammatory responses were determined by a mucosal injury score, histological examination and measurement of the myeloperoxidase (MPO) activity of tissues. The content of malonylaldehyde (MDA) and NO metabolites in colon homogenates was also measured to assess the effects of these substances on NO and free oxygen radical production. RESULTS: Estimation of colonic damage by mucosal injury scoring was found to be strongly correlated with the histologic evaluation of colon specimens. On the other hand, mucosal injury scores were not correlated with MPO, MDA or NO values. There were significant differences between the MPO results of chronic-control and chronic-honey groups, as well as chronic-control and chronic-prednisolone groups (p = 0.03 and p = 0.0007). The acute honey, prednisolone, and disulfiram groups had significantly lower MDA results compared to the acute control group (p = 0.04, p = 0.02, and p = 0.04). In terms of NO, there was no significant difference between the treatment and control groups. NO was found to have a strong relationship with MDA (p = 0.03) and MPO values (p = 0.001). On the other hand, MPO results were not found to be correlated with MDA values (p > 0.05). CONCLUSIONS: MPO activity is not directly proportional to the severity of the inflammation, but it may only determine the amount of neutrophil in the tissues. Inflammatory cells are not the sole intensifying factor in colitis. Therefore, mucosal injury scores may not correlate well with MPO activities. In an inflammatory state NO and MPO levels have a strong relationship, since NO is released from the neutrophils. In an inflammatory model of colitis, intrarectal honey administration is as effective as prednisolone treatment. Honey may have some features in the treatment of colitis, but this issue requires further investigation. Honey, prednisolone and even disulfiram also have some value in preventing the formation of free radicals released from the inflamed tissues. Prednisolone may also have some possible benefits in the inhibition of NO production in colitis therapy.