Correlation of fear memory in a PTSD animal model and hippocampal BDNF in response to β-estradiol treatment

         The most important characteristics of PTSD, as an anxiety disorder, are memory disorders and hippocampus is one of the essential structures which plays a critical role in PTSD memory disorders. Traumatic events cause apoptosis and alter the expression of neurotrophic factors in hippocampus. The aim of this study is to evaluate the effects of β-Estradiol on behavioral responses in PTSD and to study its biochemical and histological mechanisms.We used single prolonged stress (SPS) to develop PTSD in rats. The day after, the rats received electrical foot shock within shock chamber. One week later, in order to test the conditioned fear responses, the freezing behavior of rats were examined for 5 continuous days, as they were placed back in the chamber without any shock. Animals received multiple injections of β-estradiol or sesame oil, immediately after shock and also on a daily basis through the seven days prior to the test. Hippocampal cell count was implemented after cresyl violet staining. We measured BDNF protein levels by ELISA kit.Main findings of this study confirmed that exaggerated fear response is observed in PTSD group as compared with control group and β-estradiol administration reduced these exaggerated behavioral responses. We found out that SPS decreases the density of cells in hippocampus and this effect is partly corrected by β-estradiol; β-estradiol increased BDNF protein level in hippocampus as compared with PTSD group; BDNF protein level was negatively correlated with freezing response in both SPS+β-estradiol and SPS+sesame group.The results of this study is consistent with the hypothesis that decreased expression of BDNF contributes to memory impairment in PTSD and up regulation of BDNF by β-estradiol plays a role in memory treatment

Hypocalcemic seizure and related factors after neonatal period; A single-center, retrospective study

      Seizures are the most common disorder of the central nervous system in childhood and constitute a significant number of admissions to the pediatric emergency departments. The aim of this study is evaluate the etiology of hypocalcemic seizures in pediatrics. A single-center, hospital based descriptive study was done in the academic referral center for hypocalcemic seizure of Tehran University of Medical Sciences, Iran. Data was evaluated based on the medical records of each patient. Case files of these children’s were analyzed for age at presentation, sex, weight, clinical features, biochemical parameters (serum calcium, magnesium, phosphorus and alkaline phosphatase) ,type of seizure, history of previous seizure and history of drug intake.  A total 38 children with hypocalcemic seizure, consisting of 19 boys and 19 girls, with ages ranging from one month to 14 years, were enrolled in this study. The most common patterns of seizures were generalized seizures (83.8%). the mean levels of serum alkaline phosphatase was significantly greater in patients under the age of 2 years (1234 ± 541.03) rather above than 7 years of age (922.75 ± 147.45) (p = .021). Rickets was the commonest cause of seizures rickets were diagnosis in  80.8% subjects  under 2 years of age, whereas none of those over 7 years old had not rickets , these  results were statistically significant (p = .015). Current observational study indicates that rickets could be a major cause of hypocalcemic convulsion in infants and children. Screening children presenting with hypocalcemic convulsions for rickets and/or other cause of hypocalcemia can help in early diagnosis and institution of specific therapy.

Low-power density of 950 MHz radiation does not affect long-term potentiation in rat dentate gyrus

Introduction: Over the last decade, exposure to non-ionizing electromagnetic waves due to base station antenna has increased. This in vivo study was planned for evaluating the effects of whole-body exposure to 950 MHz field of GSM mobile phone system on rat dentate gyrus long-term potentiation. Materials and methods: 24 naive male Wistar rats (3 month old, 225±25 g) were randomly divided in the three groups (sham-exposed, GSM and continuous field exposed). The exposure program was planned for 10 sessions at 3 days. Animals were exposed to electromagnetic field for 45 minutes in a circular plastic chamber (mean power density=0.835 mW/cm2). Immediately after end exposure, anesthesia was induced for long term potentiation (LTP) induction. Field potentials were recorded and analyzed using the population spike amplitude and EPSP slope for 60-min. Results; There were no significant differences in population spike amplitude, EPSP slope and EPSP slope maintenance among the three groups. Conclusion: This study provides no evidence indicating that long-term potentiation can be affected by the whole-body exposure to low-power density of 950 MHz field of GSM mobile phone System

Comparison of Methods of RNA Extraction From Breast and Gastric Cancer Tissues

Objective: Optimal quality and quantity of extracted RNA is the first step in molecular biology analysis and investigation. In this way, several methods have been proposed in order to obtain the best quality of RNA in different cases. On the other hand, RNA extraction from cells and tissues is different. Materials and Methods: In this study, the effects of 4 common RNA extraction kits including Trizol, AccuZol, Ribozol and TriPure and also the effect of RNAlater and liquid nitrogen were compared and studied on 50 breast cancer and 50 gastric cancer tissues. Remarkably, the quality of the extracted RNA was investigated using real-time PCR TaqMan assay on HER2 gene. Results: The results showed better relative quality of extracted RNA with Trizol kit compared to other kits in this study. Conclusion: Conspicuously, fewer amount of tissues between 10 to 30 mg lead to gain a much better quality of RNA. Meanwhile, the expression of HER2 gene indicates a suitable performance of extracted RNA qualitatively and quantitatively. Notably, GAPDH gene was used as internal control in all samples

Input source and strength influences overall firing phase of model hippocampal CA1 pyramidal cells during theta: Relevance to REM sleep reactivation and memory consolidation

In simulation studies using a realistic model CA1 pyramidal cell, we accounted for the shift in mean firing phase from theta cycle peaks to theta cycle troughs during rapid-eye movement (REM) sleep reactivation of hippocampal CA1 place cells over several days of growing familiarization with an environment (Brain Res 855:176–180). Changes in the theta drive phase and amplitude between proximal and distal dendritic regions of the cell modulated the theta phase of firing when stimuli were presented at proximal and distal dendritic locations. Stimuli at proximal dendritic sites (proximal to 100 Μm from the soma) invoked firing with a significant phase preference at the depolarizing theta peaks, while distal stimuli (>290 Μm from the soma) invoked firing at hyperpolarizing theta troughs. The input location-related phase preference depended on active dendritic conductances, a sufficient electrotonic separation between input sites and theta-induced subthreshold membrane potential oscillations in the cell. The simulation results predict that the shift in mean theta phase during REM sleep cellular reactivation could occur through potentiation of distal dendritic (temporo-ammonic) synapses and depotentiation of proximal dendritic (Schaffer collateral) synapses over the course of familiarization. © 2006 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49532/1/20143_ftp.pd

Prevalence of overweight and obesity among Chinese Yi nationality: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Overweight and obesity are considered a serious health problem. There are little data on the prevalence of overweight and obesity among the Yi ethnic group in China. This study aimed to investigate the epidemiologic features of overweight/obesity among Chinese Yi nationality.</p> <p>Methods</p> <p>A cross-sectional study, including 1255 subjects aged 20-75 years, was carried out in Liangshan Yi Autonomous Prefecture of Sichuan province from 2007 to 2008. Overweight/overall obesity was defined by World Health Organization (WHO) or the Working Group on Obesity in China.</p> <p>Results</p> <p>Overall, the prevalence of overweight and obesity was 19.0% and 2.9%, respectively, based on the WHO definition, while it was 21.0% and 7.4%, respectively, according to the Working Group on Obesity in China, which is similar to data reported in the 2002 Chinese National Nutrition and Health Survey. Urban residents had a significantly higher prevalence of obesity (WHO criteria: 4.3% vs 1.7% <it>p </it>= 0.008; China criteria: 11.4% vs 3.7%, <it>p </it>< 0.001) and overweight (WHO criteria: 28.9% vs 8.9% <it>p </it>< 0.001; China criteria: 31.2% vs 10.4%, <it>p </it>< 0.001) than that in rural residents. Older age, a family history of obesity, higher income, drinking and urban residence were significantly associated with an increased risk of overweight/obesity.</p> <p>Conclusions</p> <p>The prevalence of overweight/obesity in the Yi nationality is similar to that in Chinese adults 5 years ago. However, urban residents have a much higher prevalence of overweight/obesity than their rural counterparts. Lifestyle and diet patterns associated with socioeconomic status may explain the difference between urban and rural residents. The prevention of overweight/obesity among urban inhabitants deserves more attention in national health education programs.</p

Assessing animal affect: an automated and self-initiated judgement bias task based on natural investigative behaviour

Scientific methods for assessing animal affect, especially affective valence (positivity or negativity), allow us to evaluate animal welfare and the effectiveness of 3Rs Refinements designed to improve wellbeing. Judgement bias tasks measure valence; however, task-training may be lengthy and/or require significant time from researchers. Here we develop an automated and self-initiated judgement bias task for rats which capitalises on their natural investigative behaviour. Rats insert their noses into a food trough to start trials. They then hear a tone and learn either to stay for 2 s to receive a food reward or to withdraw promptly to avoid an air-puff. Which contingency applies is signalled by two different tones. Judgement bias is measured by responses to intermediate ambiguous tones. In two experiments we show that rats learn the task in fewer sessions than other automated variants, generalise responses across ambiguous tones as expected, self-initiate 4-5 trials/min, and can be tested repeatedly. Affect manipulations generate main effect trends in the predicted directions, although not localised to ambiguous tones, so further construct validation is required. We also find that tone-reinforcer pairings and reinforcement or non-reinforcement of ambiguous trials can affect responses to ambiguity. This translatable task should facilitate more widespread uptake of judgement bias testing

Reward devaluation disrupts latent inhibition in fear conditioning

Three experiments explored the link between reward shifts and latent inhibition (LI). Using consummatory procedures, rewards were either downshifted from 32% to 4% sucrose (Experiments 1–2), or upshifted from 4% to 32% sucrose (Experiment 3). In both cases, appropriate unshifted controls were also included. LI was implemented in terms of fear conditioning involving a single tone-shock pairing after extensive tone-only preexposure. Nonpreexposed controls were also included. Experiment 1 demonstrated a typical LI effect (i.e., disruption of fear conditioning after preexposure to the tone) in animals previously exposed only to 4% sucrose. However, the LI effect was eliminated by preexposure to a 32%-to-4% sucrose devaluation. Experiment 2 replicated this effect when the LI protocol was administered immediately after the reward devaluation event. However, LI was restored when preexposure was administered after a 60- min retention interval. Finally, Experiment 3 showed that a reward upshift did not affect LI. These results point to a significant role of negative emotion related to reward devaluation in the enhancement of stimulus processing despite extensive nonreinforced preexposure experience

Gastrin-Releasing Peptide Signaling Plays a Limited and Subtle Role in Amygdala Physiology and Aversive Memory

Links between synaptic plasticity in the lateral amygdala (LA) and Pavlovian fear learning are well established. Neuropeptides including gastrin-releasing peptide (GRP) can modulate LA function. GRP increases inhibition in the LA and mice lacking the GRP receptor (GRPR KO) show more pronounced and persistent fear after single-trial associative learning. Here, we confirmed these initial findings and examined whether they extrapolate to more aspects of amygdala physiology and to other forms of aversive associative learning. GRP application in brain slices from wildtype but not GRPR KO mice increased spontaneous inhibitory activity in LA pyramidal neurons. In amygdala slices from GRPR KO mice, GRP did not increase inhibitory activity. In comparison to wildtype, short- but not long-term plasticity was increased in the cortico-lateral amygdala (LA) pathway of GRPR KO amygdala slices, whereas no changes were detected in the thalamo-LA pathway. In addition, GRPR KO mice showed enhanced fear evoked by single-trial conditioning and reduced spontaneous firing of neurons in the central nucleus of the amygdala (CeA). Altogether, these results are consistent with a potentially important modulatory role of GRP/GRPR signaling in the amygdala. However, administration of GRP or the GRPR antagonist (D-Phe6, Leu-NHEt13, des-Met14)-Bombesin (6–14) did not affect amygdala LTP in brain slices, nor did they affect the expression of conditioned fear following intra-amygdala administration. GRPR KO mice also failed to show differences in fear expression and extinction after multiple-trial fear conditioning, and there were no differences in conditioned taste aversion or gustatory neophobia. Collectively, our data indicate that GRP/GRPR signaling modulates amygdala physiology in a paradigm-specific fashion that likely is insufficient to generate therapeutic effects across amygdala-dependent disorders