The impact of sleep deprivation on hippocampal-mediated learning and memory in rats.

BACKGROUND: To examine the impact of different types of sleep deprivation on hippocampal-mediated learning and memory in rats. METHODS: Forty-eight Sprague-Dawley male rats were randomly assigned to 1 of 4 equal-size groups: (1) 12 hours of sleep per day (control). (2) total sleep deprivation (TSD), (3) rapid eye movement (REM) deprivation (RD), and (4) sleep restricted to 4 hours per day (SR). All rats were subjected to swimming training in the Morris water maze (MWM). At the end of the experiments, the rats were decapitated, and hippocampus tissue was analyzed for several neurotransmitters and receptors. RESULTS: The time spent at the target quadrant increased from 20.2 to 30.0 seconds in the control group on the third day of the experiment, whereas corresponding values increased from 20.2 to 21.8 seconds in the TSD group, 22.1 to 25.4 seconds in the RD group, and 21.2 to 32.0 sec in the SR group (p = 0.026). On the seventh day of the experiment, the values decreased to 25.0 seconds in controls, 22.5 in the RD group, and 23.6 in the SR group (p = 0.045). The TSD group demonstrated significant decreases in glutamate and serotonin levels compared with the control group. There was a significant increase in 5-HT2a receptor expression in all intervention groups compared with the controls. CONCLUSIONS: Our results of glutamate levels and 5-HT2a receptor expression in the hippocampus seem to be primarily involved in sleep and memory regulation (Tab. 2, Fig. 4, Ref. 59).

Vitamin C attenuates methotrexate-induced oxidative stress in kidney and liver of rats.

Like several other anticancer drugs, methotrexate (MTX) causes side effects, such as neuropathic pain, hepatotoxicity, and nephrotoxicity. Abnormal production of reactive oxygen species has been suspected in the pathophysiology of MTX-induced hepatorenal toxicity. Therefore, the aim of this study was to investigate the probable protective role of vitamin C (Vit C) on oxidative stress induced by MTX in the liver and kidney tissues of rats. A total of 32 rats were randomly and equally divided into four groups. The first group served as the control group. The second group received a single dose of 20 mg/kg of MTX intraperitoneally. To demonstrate our hypothesis, the third and the fourth groups received 250 mg/kg of Vit C for 3 days by oral gavage, with or without MTX treatment. At the end of the study, the liver and kidney tissues of the rats were collected and examined using histology. Both the tissues were assayed for malondialdehyde concentration and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities. In hepatic and renal tissues, lipid peroxidation levels were increased, whereas SOD, CAT, and GSH-Px levels were decreased by MTX. All parameters, including CAT levels in hepatic tissue, were significantly restored after the administration of Vit C for 3 days. Similar to the biochemical findings, evidence of oxidative damage was examined in both types of tissues by histopathological examination. From the results of this study, we were able to observe that Vit C administration modulates the antioxidant redox system and reduces the renal and hepatic oxidative stress induced by MTX. Vit C can ameliorate the toxic effect of MTX in liver and kidney tissues of rat.

Does maternal exposure to artificial food coloring additives increase oxidative stress in the skin of rats?

Glutathione-S-transferase (GST) and cytochrome P450 family 1 subfamily A polypeptide 1 (CYP1A1) metabolize and detoxify carcinogens, drugs, environmental pollutants, and reactive oxygen species. Changes of GST expression in tissues and gene mutations have been reported in association with many neoplastic skin diseases and dermatoses. Widely used artificial food coloring additives (AFCAs) also reported to effect primarily behavioral and cognitive function and cause neoplastic diseases and several inflammatory skin diseases. We aimed to identify the changes in expression of GSTs, CYP1A1, and vascular endothelial growth factor (VEGF) in rat skin which were maternally exposed AFCAs. A rat model was designed to evaluate the effects of maternal exposure of AFCAs on skin in rats. "No observable adverse effect levels" of commonly used AFCAs as a mixture were given to female rats before and during gestation. Immunohistochemical expression of GSTs, CYP1A1, and VEGF was evaluated in their offspring. CYP1A1, glutathione S-transferase pi (GSTP), glutathione S-transferase alpha (GSTA), glutathione S-transferase mu (GSTM), glutathione S-transferase theta (GSTT), and VEGF were expressed by epidermal keratinocytes, dermal fibroblasts, sebaceous glands, hair follicle, and subcutaneous striated muscle in the normal skin. CYP1A1, GSTA, and GSTT were expressed at all microanatomical sites of skin in varying degrees. The expressions of CYP1A1, GSTA, GSTT, and VEGF were decreased significantly, while GSTM expression on sebaceous gland and hair follicle was increased. Maternal exposure of AFCAs apparently effects expression of the CYP1A1, GSTs, and VEGF in the skin. This prominent change of expressions might play role in neoplastic and nonneoplastic skin diseases.

The effects of electromagnetic radiation (2450 MHz wireless devices) on the heart and blood tissue: role of melatonin.

OBJECTIVE: This study was designed to investigate the effects of 2450 MHz EMR on the heart and blood in rat and possible ameliorating effects of melatonin. MATERIAL AND METHOD: Thirty-two female Wistar Albino rats were randomly grouped (by eight in each group) as follows:  Group I: cage-control group (dimethysulfoxide (DMSO), 10mg/kg/day i.p. without stress and EMR. Group II: sham-control rats stayed in restrainer without EMR and DMSO (10mg/kg/day i.p.). Group III: rats exposed to 2450 MHz EMR. Group IV: treated group rats exposed to 2450 MHz EMR+melatonin (MLT) (10mg/kg/day i.p.). RESULTS: In the blood tissue, there was no significant difference between the groups in respect of erythrocytes GSH, GSH-Px activity, plasma LP level and vitamin A concentration (p > 0.05). However, in the Group IV, erythrocytes' LP levels (p < 0.05) were observed to be significantly decreased while plasma vitamin C, and vitamin E concentrations (p < 0.05) were found to be increased when compared to Group III. In the heart tissues, MDA and NO levels significantly increased in group III compared with groups I and II (p < 0.05). Contrary to these oxidant levels, CAT and SOD enzyme activities decreased significantly in group III compared with groups I and II (p 0.05). Besides, MLT treatment lowered the MDA and NO levels compared with group III. DISCUSSION: In conclusion, these results demonstrated that contrary to its effect on the heart, the wireless (2450 MHz) devices cause slight oxidative-antioxidative changes in the blood of rats, and a moderate melatonin supplementation may play an important role in the antioxidant system (plasma vitamin C and vitamin E). However, further investigations are required to clarify the mechanism of action of the applied 2450 MHz EMR exposure (Tab. 3, Fig. 1, Ref. 49).

The evaluation of Nesfatin-1 levels in patients with OSAS associated with metabolic syndrome.

PURPOSE: The association of obstructive sleep apnea syndrome (OSAS) and metabolic syndrome (MS) has been demonstrated in studies and in recent years; the effect of OSAS on insulin resistance independent of the level of obesity is being investigated. Nesfatin-1 is a newly defined 82 amino acid protein with a precursor molecule of NUCB2 (nucleobindin 2). Nesfatin-1 is not only essential in regulation of food ingestion but also important in regulation of some brain functions, autonomic regulation, stress, mental state, and paradoxical sleep. We aimed to evaluate the relationship between OSAS and MS and the MS dependent or independent effect of Nesfatin-1 on this relationship. METHODS: Patients admitted with clinical signs of OSAS are included. Patients are divided into three groups based on Apnea-Hypopnea Index (AHI) on Polysomnography (PSG) as mild, moderate, and severe OSAS. A total of 59 patients were included the control patients. Several OSAS parameters and laboratory findings which are and are not MS dependent are compared. Nesfatin-1 levels are evaluated in all OSAS patients with and without MS. RESULTS: There were significantly more males in all groups (p = 0.007). There was no significant difference between groups in terms of Nesfatin-1 levels. Nesfatin-1 levels were significantly lower in MS group compared to non-MS group (p = 0.021). CONCLUSION: Nesfatin-1 which is known to play a role in the pathophysiology of insulin resistance can be a beneficial target in developing new therapeutic targets for treatment of patients with obesity without any toxic effects in the future.

Evaluation of stress and pain during rapid maxillary expansion treatments.

The purpose of this study was to use salivary cortisol levels, pressure pain threshold (PPT) and Spielberger's State-Trait Anxiety Inventory for Children (STAIC) to assess stress, anxiety and pain during the expansion and retention phase of rapid maxillary expansion (RME) in children and investigate to whether this parameters are associated with gender or skeletal maturity stages. STAIC was used to assess the anxiety levels of the children. Salivary samples were collected for stress hormone determination. Visual Analog Scale was used for pain determination. Pressure pain threshold (PPT) was measured by using algometer. Data collection was performed a week before RME treatment (T0), at the day of the expansion appliance was bonded (T1), at the days of 1st, 4th, 7th, 14th, 25th, 36th activations of expansion screw (T2, T3, T4, T5, T6, T7) and after the retention period of 3 months (T8). The results of this study showed that the differences were statistically significant within-day (P < 0·001) and within-hours (P < 0·001) in cortisol levels during treatment. PPT levels were statistically significant within sex differences and skeletal maturity stages (P < 0·05). State-trait anxiety scale scores were similar with respect to gender (P > 0·05). There were statistically significant differences of state-trait anxiety levels between pre and post-treatment stages (P < 0·05). The maximum number of patients reporting pain were days at T3 and T4. From day T5 the percentage of patients reporting pain then gradually reduced. Based on the findings of this study, it has been shown that RME leads to changes in patients' state-trait anxiety and cortisol levels.

Role of reactive oxygen species in organophosphate insecticide phosalone toxicity in erythrocytes in vitro.

Reactive oxygen species (ROS) caused by organophosphates may be involved in the toxicity of various pesticides. Therefore, in this study we aimed to investigate how an organophosphate insecticide, phosalone, affects lipid peroxidation (LPO) and the antioxidant defence system in vitro. For this purpose, the effects of various doses of phosalone on LPO and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) in erythrocytes were studied. Each phosalone dose was incubated with a previously prepared erythrocyte sample at +4 degrees C for 0, 60 and 180 min. After incubation, the levels of malondialdehyde (MDA) and the activities of SOD, GSH-Px and CAT were determined. Phosalone caused an increase in MDA formation and a decrease in the activities of SOD, GSH-Px and CAT. However, these effects were seen only at extremely high concentrations of phosalone and these concentrations were in the lethal range. Therefore, we suggest that ROS may not involve in the toxic effects of the pesticidal use of phosalone in low concentrations.