Satheesha B Nayak

Spatial memory perfomance of wistar rats exposed to mobile phone

INTRODUCTION With the tremendous increase in number of mobile phone users world wide, the possible risks of this technology have become a serious concern. OBJECTIVE We tested the effects of mobile phone exposure on spatial memory performance. MATERIALS AND METHODS Male Wistar rats (10–12 weeks old) were exposed to 50 missed calls/day for 4 weeks from a GSM (900/1800MHz) mobile phone in vibratory mode (no ring tone). After the experimental period, the animals were tested for spatial memory performance using the Morris water maze test. RESULTS Both phone exposed and control animals showed a significant decrease in escape time with training. Phone exposed animals had significantly (~3 times) higher mean latency to reach the target quadrant and spent significantly (~2 times) less time in the target quadrant than age- and sex-matched controls. CONCLUSION Mobile phone exposure affected the acquisition of learned responses in Wistar rats. This in turn points to the poor spatial navigation and the object place configurations of the phone-exposed animals.

Effect of radio-frequency electromagnetic radiations (RF-EMR) on passive avoidance behaviour and hippocampal morphology in Wistar rats

Abstract Introduction. The interaction of mobile phone radio-frequency electromagnetic radiation (RF-EMR) with the brain is a serious concern of our society. Objective. We evaluated the effect of RF-EMR from mobile phones on passive avoidance behaviour and hippocampal morphology in rats. Materials and methods. Healthy male albino Wistar rats were exposed to RF-EMR by giving 50 missed calls (within 1 hour) per day for 4 weeks, keeping a GSM (0.9 GHz/1.8 GHz) mobile phone in vibratory mode (no ring tone) in the cage. After the experimental period, passive avoidance behaviour and hippocampal morphology were studied. Results. Passive avoidance behaviour was significantly affected in mobile phone RF-EMR-exposed rats demonstrated as shorter entrance latency to the dark compartment when compared to the control rats. Marked morphological changes were also observed in the CA3 region of the hippocampus of the mobile phone-exposed rats in comparison to the control rats. Conclusion. Mobile phone RF-EMR exposure significantly altered the passive avoidance behaviour and hippocampal morphology in rats.

Ascorbic acid protects against restraint stress-induced memory deficits in wistar rats

OBJECTIVE: Chronic stress has been shown to cause oxidative damage in the central nervous system. Although stress-induced impairments in learning and memory have been studied extensively, very few studies have investigated possible ways to prevent their ill effects. The present work was designed to study the protective effects of ascorbic acid in memory loss induced by chronic restraint stress. METHODS: Adult male Wistar rats were designated into the following groups: (i) Normal control, (ii) Ascorbic acid treatment, (iii) Vehicle control, (iv) Restraint stress, (v) Restraint stress + vehicle, and (vi) Restraint stress + ascorbic acid treatment. At the end of 21 days, animals of all groups were subjected to memory tests using Morris water maze and passive avoidance apparatus. Then, the results obtained were compared between the experimental groups. RESULTS: Rats exposed to restraint stress alone and those pretreated with vehicle solution before restrained stress showed deficits in learning and impaired memory retention in the memory tests when compared to animals in other experimental groups. Animals pretreated with ascorbic acid before restraining showed significant improvement in memory retention in the same memory tests. CONCLUSIONS: Results of this study suggest the possibility of using ascorbic acid as a dietary supplement to prevent stress-induced memory impairments.

Progressive drawing: A novel “lid–opener” and “monotony–breaker”

An innovative strategy called “progressive drawing” was used at the beginning (lid‐opener) and later (monotony‐breaker) during gross anatomy lectures. Diagrams were drawn on the classroom blackboard with anatomic structures added one by one. Students identified and labeled the diagrams and predicted the next structures to be drawn. Students felt that the strategy helped to activate prior knowledge, created interest in the current lecture, and made lecture sessions more interactive. The strategy has appeal for visual, auditory, read/write, and kinesthetic learners. Anat Sci Educ, 2010.

Enhancement of basolateral amygdaloid neuronal dendritic arborization following Bacopa monniera extract treatment in adult rats

OBJECTIVE: In the ancient Indian system of medicine, Ayurveda, Bacopa monniera is classified as Medhya rasayana, which includes medicinal plants that rejuvenate intellect and memory. Here, we investigated the effect of a standardized extract of Bacopa monniera on the dendritic morphology of neurons in the basolateral amygdala, a region that is concerned with learning and memory. METHODS: The present study was conducted on 2½-month-old Wistar rats. The rats were divided into 2-, 4- and 6-week treatment groups. Rats in each of these groups were further divided into 20 mg/kg, 40 mg/kg and 80 mg/kg dose groups (n  =  8 for each dose). After the treatment period, treated rats and age-matched control rats were subjected to spatial learning (T-maze) and passive avoidance tests. Subsequently, these rats were killed by decapitation, the brains were removed, and the amygdaloid neurons were impregnated with silver nitrate (Golgi staining). Basolateral amygdaloid neurons were traced using camera lucida, and dendritic branching points (a measure of dendritic arborization) and dendritic intersections (a measure of dendritic length) were quantified. These data were compared with the data from the age-matched control rats. RESULTS: The results showed an improvement in spatial learning performance and enhanced memory retention in rats treated with Bacopa monniera extract. Furthermore, a significant increase in dendritic length and the number of dendritic branching points was observed along the length of the dendrites of the basolateral amygdaloid neurons of rats treated with 40 mg/kg and 80 mg/kg of Bacopa monniera (BM) for longer periods of time (i.e., 4 and 6 weeks). CONCLUSION: We conclude that constituents present in Bacopa monniera extract have neuronal dendritic growth-stimulating properties.

Sural nerve and short saphenous vein entrapment-a case report

Although the sural nerve is the most extensively studied nerve in man, there is a dearth of data regarding the normal variations in the size and distribution of axons in normal subjects. Since the sural nerve is the most frequently used sensory nerve in nerve transplantation, knowledge of variations in its course and distribution plays an important role in the surgical procedures. Here, an entrapment of the sural nerve in the gastrocnemius is reported. The short saphenous vein also passed through the gastrocnemius muscle along with the sural nerve.

Appraisal of the effect of brain impregnation duration on neuronal staining and morphology in a modified Golgi-Cox method.

BACKGROUND Golgi-Cox staining method is considered as one of the best neurohistological and fascinating staining techniques to reveal the cytoarchitecture of the brain. Requirement of longer time (more than a month), laborious section processing steps, requirement of sophisticated equipments and costly ready to use kits limits extensive use of this technique. NEW METHOD The need for a modified staining technique is to overcome some of these hurdles. Here we describe a modification of Golgi-Cox staining involving reduced impregnation time (7 days), omitting tissue dehydration steps, and alterations in section processing steps. Different impregnation duration (7 days, 14 days, 1 month, 6 months and 10 months) effects on optimized staining of dorsal hippocampus and basolateral amygdala were investigated. RESULTS Modified Golgi-Cox staining method was found to be effective in staining rat hippocampus and amygdala. Impregnation for 7 days, 14 days and 1 month resulted in giving good results and they were comparable. However, artifacts were slightly elevated with 6 months group but not extensively. Impregnation for 10 months negatively affected the staining process. COMPARISON WITH EXISTING METHOD(S) Compared to existing methods the current method was found to be cost effective, fast, reliable and can be executed in labs where infrastructure is limited. CONCLUSIONS Current modification considerably benefitted in obtaining better results (good clarity and lesser artifact) in a short time. Longer impregnated brain sections were found to be unsuitable for morphometric evaluation due to more stain precipitation and artifact. The modified technique can be used to study cellular architecture in other brain regions.

Evaluation of oxidant stress and antioxidant defense in discrete brain regions of rats exposed to 900 MHz radiation

AIM In the current study, the effects of 900 MHz radio-frequency electromagnetic radiation (RF-EMR) on levels of thiobarbituric acid-reactive substances (TBARS), total antioxidants (TA), and glutathione S-transferase (GST) activity in discrete brain regions were studied in adolescent rats. MATERIALS AND METHODS Thirty-six male Wistar rats (6-8 weeks old) were allotted into three groups (n = 12 in each group). Control group (1) remained undisturbed in their home cage; sham group (2) was exposed to mobile phone in switch off mode for four weeks; RF-EMR-exposed group (3) was exposed to 900 MHz of RF-EMR (1 hr/day with peak power density of 146.60 µW/cm2) from an activated Global System for Mobile communication (GSM) mobile phone (kept in silent mode; no ring tone and no vibration) for four weeks. On 29th day, behavioral analysis was done. Followed by this, six animals from each group were sacrificed and biochemical parameters were studied in amygdala, hippocampus, frontal cortex, and cerebellum. RESULTS Altered behavioral performances were found in RF-EMR-exposed rats. Additionally, elevated TBARS level was found with all brain regions studied. RF-EMR exposure significantly decreased TA in the amygdala and cerebellum but its level was not significantly changed in other brain regions. GST activity was significantly decreased in the hippocampus but, its activity was unaltered in other brain regions studied. CONCLUSION RF-EMR exposure for a month induced oxidative stress in rat brain, but its magnitude was different in different regions studied. RF-EMR-induced oxidative stress could be one of the underlying causes for the behavioral deficits seen in rats after RF-EMR exposure (Fig. 5, Ref. 37).

Morphological variations of the lungs: a study conducted on Indian cadavers

Awareness of anatomical variations in lungs is essential during segmental or lobar resections of lungs. We studied the variations of fissures, lobes and hilar structures in 65 right and 73 left isolated lungs from the dissection hall. Horizontal fissure was absent in 3.07% and incomplete in 35.38% of right lungs. Four point six one percentage of right lungs had 3 fissures and 4 lobes. Three point zero seven percentage of right lungs had 3 arteries, 67.69% had 2 arteries, and 29.23% had only one artery in the hilum. Sixty-three point zero seven percentage of right lungs had two veins in the hilum; 32.30% had 3 veins in the hilum; and 4.61% had more than 3 veins in the hilum. Ninety-eight point four six percentage of right lungs showed 2 bronchi in the hilum, and 1.53% of them showed 3 bronchi in the hilum. Two of the right lungs (3.07%) had an artery passing across the oblique fissure. Fifteen point zero six percentage of left lungs showed incomplete oblique fissure and 2.73% showed 2 fissures and 3 lobes. Five point four seven percentage of left lungs showed 2 arteries and 94.52% had only one artery in the hilum. Eighty point eight two percentage of left lungs had two veins in the hilum and 19.17% had 3 veins in the hilum. Twenty-one point nine one percent of left lungs had 2 bronchi and 78.08% had only one bronchus in the hilum. The knowledge of variations in the lobar and hilar anatomy of the lung presented in this study is clinically important while interpreting the radiological images and performing surgical procedures.

A peculiar liver with surgically and radiologically important variations: a case report

A peculiar liver was found in an adult male cadaver during a dissection class for undergraduate medical students. The quadrate lobe and fissure for the ligamentum teres were totally absent. Thus, the cystic notch on the inferior border was very broad and deep, and the fundus and body of the gall bladder popped out through this notch. The cystic duct terminated into the right hepatic duct at the porta hepatis instead of terminating into the common hepatic duct. Awareness of variations of the lobes and fissures may minimize a misdiagnosis of liver problems. The aim of the current study was to alert radiologists and surgeons about possible variations in the external appearance and anomalies of the lobes and fissures of the liver.