Comparison of three supraglottic airway devices for blind tracheal intubation by novice practitioners: A randomized manikin study.

OBJECTIVES: Supraglottic airway (SGA) devices are good alternatives for failed intubations or difficult airways. The aim of our study was to compare the success of intubation with SGA devices such as LMA Fastrach® (LMA Fastrach), Ambu Aura-i® (Aura-i), and Cookgas Air-Q® (Air-Q) in an airway manikin by novice practitioners. METHODS: This study was conducted in a randomized crossover design using a manikin model. Following training on the equipment used, 36 6th-year medical students were randomized into six groups. Participants performed three stages of intubation as follows: the first stage (1S) as SGA insertion, the second stage (2S) as intubation through the SGA, and the third stage (3S) as the removal of the SGA over the intubation tube. The primary outcomes were intubation success and duration. RESULTS: The successful intubation rate (Stage 1S + 2S + 3S) was 100% for LMA Fastrach and Air-Q and 83.3% for Aura-i (P = 0.002). The median time to intubation was 54.4 s, 55.8 s, and 58.7 s for LMA Fastrach, Aura-i, and Air-Q, respectively (P = 0.794). CONCLUSION: Our study shows that novice practitioners can proficiently utilize LMA Fastrach, Air-Q, and Aura-i as SGAs in airway management. LMA Fastrach and Air-Q are more successful for endotracheal intubation than Aura-i. While the successful intubation time with SGA is similar for all three devices, the successful SGA insertion time is shorter with LMA Fastrach and Aura-i compared to Air-Q. Practitioners preferred LMA Fastrach and Air-Q more than Aura-i.

The Role of Glycogen Synthase Kinase-3ß in the Zinc-Mediated Neuroprotective Effect of Metformin in Rats with Glutamate Neurotoxicity.

Metformin has been suggested to have protective effects on the central nervous system, but the mechanism is unknown. The similarity between the effects of metformin and the inhibition of glycogen synthase kinase (GSK)-3ß suggests that metformin may inhibit GSK-3ß. In addition, zinc is an important element that inhibits GSK-3ß by phosphorylation. In this study, we investigated whether the effects of metformin on neuroprotection and neuronal survival were mediated by zinc-dependent inhibition of GSK-3ß in rats with glutamate-induced neurotoxicity. Forty adult male rats were divided into 5 groups: control, glutamate, metformin + glutamate, zinc deficiency + glutamate, and zinc deficiency + metformin + glutamate. Zinc deficiency was induced with a zinc-poor pellet. Metformin was orally administered for 35 days. D-glutamic acid was intraperitoneally administered on the 35th day. On the 38th day, neurodegeneration was examined histopathologically, and the effects on neuronal protection and survival were evaluated via intracellular S-100ß immunohistochemical staining. The findings were examined in relation to nonphosphorylated (active) GSK-3ß levels and oxidative stress parameters in brain tissue and blood. Neurodegeneration was increased (p < 0.05) in rats fed a zinc-deficient diet. Active GSK-3ß levels were increased in groups with neurodegeneration (p < 0.01). Decreased neurodegeneration, increased neuronal survival (p < 0.01), decreased active GSK-3ß (p < 0.01) levels and oxidative stress parameters, and increased antioxidant parameters were observed in groups treated with metformin (p < 0.01). Metformin had fewer protective effects on rats fed a zinc-deficient diet. Metformin may exert neuroprotective effects and increase S-100ß-mediated neuronal survival by zinc-dependent inhibition of GSK-3ß during glutamate neurotoxicity.

Deep phenotyping of miRNAs in exercise-induced cardiac hypertrophy and fibrosis.

Cardiac hypertrophy (CH) is an adaptational enlargement of the myocardium, in exposure to altered stress conditions or in case of injury which can lead to heart failure and death. MicroRNAs (miRNAs) are noncoding RNAs that play a significant role in modulating gene expression. Here, we aimed to identify new miRNAs effective in an experimental CH model and to find an epigenetic biomarker that could demonstrate therapeutic targets responsible for the pathology of heart tissue and serum. In this study, Sprague-Dawley male rats were divided into the training group (TG, n=9) and the control group (CG, n=6). Systolic and diastolic dimensions of the left ventricle and myocardial wall thickness were measured by echocardiography to assess CH. After the exercise program of the rats, miRNA expression measurements and histological analyses were performed. The 25,000 genes in the rat genome were searched using microarray analysis. A total of 128 miRNAs were selected according to the fold change rates, and nine miRNAs were validated for expression analysis. The terminal deoxynucleotidyl transferase dUTP nick (TUNEL) method was used to detect apoptotic cells. Cell proliferation was evaluated by the proliferative cell nuclear antigen (PCNA) method. Necrosis, bleeding, and intercellular edema were detected in TG. The mean histopathological score was higher in TG (p=0.03). There were rarely positive cells for apoptosis of both groups in cardiomyocytes. In the receiver characteristic curve analysis (ROC), the heart tissue rno-miR-290 had an area under the curve (AUC) of 0.920 with 100% sensitivity and 89.90% specificity (p=0.045), rno-miR-194-5p had AUC of 0.940 with 83.33% sensitivity and 100% specificity (p=0.003), and the serum rno-miR-132-3p AUC was 0.880 with 66.67% sensitivity and 100% specificity (p=0.004) in TG. miR-194-5p was used as a therapeutic target for remodeling the cardiac process. While miR-290 contributes to CH as a negative regulator, miR-132 in serum is effective in the pathological and physiological cardiac remodeling process and is a candidate biomarker.

The role of an open artificial intelligence platform in modern neurosurgical education: a preliminary study.

The use of artificial intelligence in neurosurgical education has been growing in recent times. ChatGPT, a free and easily accessible language model, has been gaining popularity as an alternative education method. It is necessary to explore the potential of this program in neurosurgery education and to evaluate its reliability. This study aimed to show the reliability of ChatGPT by asking various questions to the chat engine, how it can contribute to neurosurgery education by preparing case reports or questions, and its contributions when writing academic articles. The results of the study showed that while ChatGPT provided intriguing and interesting responses, it should not be considered a dependable source of information. The absence of citations for scientific queries raises doubts about the credibility of the answers provided. Therefore, it is not advisable to solely rely on ChatGPT as an educational resource. With further updates and more specific prompts, it may be possible to improve its accuracy. In conclusion, while ChatGPT has potential as an educational tool, its reliability needs to be further evaluated and improved before it can be widely adopted in neurosurgical education.

Impressions of the chronic 900-MHz electromagnetic field in the prenatal period on Purkinje cells in male rat pup cerebella: is it worth mentioning?

OBJECTIVE: The aim of this study was to examine the changes on the Purkinje cells in the cerebella of male rat pups born to pregnant dams that were exposed to an electromagnetic field in the prenatal period. METHODS: The first stage of the study involved 12 Sprague-Dawley rats, 6 male and 6 female, weighing between 180 and 250 g. The female rats in the experimental group were exposed to a 900-MHz electromagnetic field for 1 h at the same time every day, and no procedure was performed on the control group. Following pregnancy, six male pups from each group were divided into experimental and control groups without any procedure on the pups. After 2 months, they were sacrificed and their cerebella were removed. Histopathologically, following routine processing and fixation procedures, the cerebella were embedded in the tissue blocks. The sections taken from these blocks were stained with cresyl violet. The Purkinje cells in the cerebella were then counted on sections using the optical dissector method on an image analysis system. RESULTS: The estimation of number of the Purkinje cells in the groups revealed more cells in rats in the control group than in the experimental group. Histopathologically, Purkinje cells exhibited a normal morphological structure in the control group, while the cells in the experimental group showed damage. CONCLUSIONS: It might be asserted that the exposure of mothers to an electromagnetic field in the prenatal period may affect the development of Purkinje cells in the pup cerebella.

Impressions of the chronic 900-MHz electromagnetic field in the prenatal period on Purkinje cells in male rat pup cerebella: is it worth mentioning?

SUMMARY OBJECTIVE: The aim of this study was to examine the changes on the Purkinje cells in the cerebella of male rat pups born to pregnant dams that were exposed to an electromagnetic field in the prenatal period. METHODS: The first stage of the study involved 12 Sprague-Dawley rats, 6 male and 6 female, weighing between 180 and 250 g. The female rats in the experimental group were exposed to a 900-MHz electromagnetic field for 1 h at the same time every day, and no procedure was performed on the control group. Following pregnancy, six male pups from each group were divided into experimental and control groups without any procedure on the pups. After 2 months, they were sacrificed and their cerebella were removed. Histopathologically, following routine processing and fixation procedures, the cerebella were embedded in the tissue blocks. The sections taken from these blocks were stained with cresyl violet. The Purkinje cells in the cerebella were then counted on sections using the optical dissector method on an image analysis system. RESULTS: The estimation of number of the Purkinje cells in the groups revealed more cells in rats in the control group than in the experimental group. Histopathologically, Purkinje cells exhibited a normal morphological structure in the control group, while the cells in the experimental group showed damage. CONCLUSIONS: It might be asserted that the exposure of mothers to an electromagnetic field in the prenatal period may affect the development of Purkinje cells in the pup cerebella.

Diagnosis of a Ruptured Pulmonary Hydatid Cyst in a 26-Week Pregnant Female With Bedside Lung Ultrasound in Emergency (BLUE) Protocol: A Case Report.

Pulmonary hydatid cyst during pregnancy is extremely rare and life-threatening for the mother and fetus. Throughout pregnancy, hydatid cysts may enlarge due to the suppression of cellular immunity and steroids secreted from the placenta. In late pregnancy, the cysts can reach a huge volume with an increased risk for subsequent rupture due to the compression of the enlarging uterus and anaphylactic shock. Intrabronchial rupture is a rare and life-threatening complication of pulmonary hydatid cysts. It is vital to diagnose it as early as possible and manage patients with surgical intervention with aggressive medical treatment. Plain radiograph, computed tomography (CT) scan, and magnetic resonance imaging (MRI) can be used to identify pulmonary hydatid cysts. However, the diagnosis of hydatid cyst is quite challenging in pregnant patients due to concerns of radiation. Herein, we present a 26-week pregnant patient with acute respiratory failure. Bedside lung ultrasound was notable for thickened and severely broken pleural line with a large subpleural consolidation, and a giant fluid-filled cyst covered almost the entire left thorax, causing a mediastinal shift. In the present case, we highlighted that the bedside lung ultrasound in emergency (BLUE) protocol is an easy, safe, and fast way to identify pulmonary hydatid cyst. It should be the initial technique of choice for the diagnosis of pulmonary hydatid cysts in pregnant patients.

Influence of semi-arid environment on radiation use efficiency and other growth attributes of lentil crop.

Solar radiation (SR) is essential for yield improvement in lentil, which is a crop of marginal environments. Herein, experiments were conducted over 2 years under a semi-arid environment to study the radiation interception (RI), efficiency, growth, and development of three lentil genotypes (Punjab Masoor-2009 (PM-2009), NIAB Masoor-2006 (NM-2006), and NIAB Masoor-2002 (NM-2002)) in relation to three nitrogen rates (13, 19, and 25 kg ha-1). Seasonal dynamics of intercepted photoactive radiation (IPAR) and cumulated photosynthetic photon flux density were highly associated with seasonal dynamics of leaf area index (LAI), with a high value of R2 (0.93 and 0.89) across all nitrogen rates and genotypes in both years. Nitrogen application promoted growth, and maximum LAI (3.97 and 3.57) and RI (324 and 301 MJ m-2) were attained for the first and second years of study, respectively. Biomass and yield were positively associated with IPAR. Variation in radiation absorption (RA) among genotypes was due to different patterns of LAI development. In both years, yield (23% and 25%) and radiation use efficiency (RUE) for grain yield (0.44 and 0.37 g MJ-1) were respectively higher for PM-2009 than for the other genotypes. Genotype PM-2009 had 15 days shorter crop cycle than others while 14% higher GDDs accumulated in the first year compared with the second due to the higher temperature. High nitrogen (25 kg ha-1) application resulted in higher dry matter (DM), and grain yield (GY), while RUE and PAR were not statistically different under 19 kg N ha-1 application across years. Genotypes PM-2009 and NM-2006 may perform reasonably well under arid to semi-arid regions at farmer field. These findings may assist researchers and crop modelers to optimize the lentil ideotype for efficient light utilization.

Protective Effect of Thymosin ß4 against Abdominal Aortic Ischemia-Reperfusion-Induced Acute Lung Injury in Rats.

Background and objectives: Ischemia-reperfusion (IR) caused by infrarenal abdominal aorta cross-clamping is an important factor in the development of ischemia-reperfusion injury in various distant organs. Materials and Methods: We investigated potential antioxidant/anti-inflammatory effects of thymosin beta 4 (Tß4) in a rat model of abdominal aortic surgery-induced IR. Tß4 (10 mg/kg, intravenous (i.v.)) was administered to rats with IR (90-min ischemia, 180-min reperfusion) at two different periods. One group received Tß4 1 h before ischemia, and the other received 15 min before the reperfusion period. Results: Results were compared to control and non-Tß4-treated rats with IR. Serum, bronchoalveolar lavage fluid and lung tissue levels of oxidant parameters were higher, while antioxidant levels were lower in the IR group compared to control. IR also increased inflammatory cytokine levels. Tß4 reverted these parameters in both Tß4-treated groups compared to the untreated IR group. Conclusions: Since there is no statistical difference between the prescribed results of both Tß4-treated groups, our study demonstrates that Tß4 reduced lung oxidative stress and inflammation following IR and prevented lung tissue injury regardless of timing of administration.

The effects of a continuous 1-h a day 900-MHz electromagnetic field applied throughout early and mid-adolescence on hippocampus morphology and learning behavior in late adolescent male rats.

The purpose of this study was to investigate hippocampus morphology and changes in learning behavior in male rats in late adolescence exposed to the effect of a continuous 1-h a day 900-megahertz (MHz) electromagnetic field (EMF). Twenty-four male Sprague Dawley rats aged 3-weeks were divided equally into control, sham and EMF groups. EMF group rats were exposed to a 900-MHz EMF inside an EMF cage, while the sham group rats were placed in the same cage but were not exposed to such an effect. No procedure was performed on the control group. Following 25-day application of EMF, passive avoidance, 8-arm radial maze and Y-maze tests were applied to determine rats' learning and memory performances. Open field and rotarod tests were applied to assess locomotor activity. At the end of the tests, the animals' brains were removed. Sections were taken and stained with toluidine blue. The regions of the hippocampus were subjected to histopathological evaluation. At histopathological examination, impairments of pyramidal and granular cell structures were observed in the EMF group hippocampus. No significant change was observed in learning, memory or locomotor behavior in any group. In conclusion, 900-MHz EMF applied in early and mid-adolescence causes no changes in learning, memory or locomotor behavior.

Improvements in quality of life in septuagenarians versus octogenarians undergoing trans-catheter aortic valve replacement.

BACKGROUND: Very elderly patients represent a distinct patient group in clinical setting in terms of a decision for trans-catheter aortic valve replacement (TAVR) when one considers the potential improvement in the quality of life (QoL) on one hand and the benefit to risk ratio on the other. This study aimed to compare functional and QoL outcomes of TAVR between octogenarians and septuagenarians. METHODS: This prospective cohort study included 136 elderly patients (70 to 89 years of age), who underwent transfemoral TAVR due to degenerative aortic stenosis. Patients were allocated into one of the following age groups: septuagenarians (n = 67) and octogenarians (n = 69). Preoperative and early postoperative clinical parameters were recorded. In addition, QoL of the patients was evaluated using SF-36 questionnaire preoperatively and six month postoperatively. RESULTS: Groups were similar in terms of early postoperative mortality and morbidity parameters. The mean New York Heart Association (NYHA) class improved after TAVR in both groups. In addition, all SF-36 norm-based scale and SF-36 summary scale scores improved significantly in both groups during the postoperative period. Postoperatively, physical functioning, general health and physical component summary scores were significantly better in the septuagenarian group (P = 0.02, 0.01, 0.03, respectively). CONCLUSION: Although the improvement in the QoL in terms of physical health was more marked in septuagenarians than in octogenarians, substantial benefits on the QoL and particularly on mental health seem to justify re-consideration of TAVR indications in the very elderly.

Pernicious effects of long-term, continuous 900-MHz electromagnetic field throughout adolescence on hippocampus morphology, biochemistry and pyramidal neuron numbers in 60-day-old Sprague Dawley male rats.

The central nervous system (CNS) begins developing in the intrauterine period, a process that continues until adulthood. Contact with chemical substances, drugs or environmental agents such as electromagnetic field (EMF) during adolescence therefore has the potential to disturb the development of the morphological architecture of components of the CNS (such as the hippocampus). The hippocampus is essential to such diverse functions as memory acquisition and integration and spatial maneuvering. EMF can result in severe damage to both the morphology of the hippocampus and its principal functions during adolescence. Although children and adolescents undergo greater exposure to EMF than adults, the information currently available regarding the effects of exposure to EMF during this period is as yet insufficient. This study investigated the 60-day-old male rat hippocampus following exposure to 900 megahertz (MHz) EMF throughout the adolescent period using stereological, histopathological and biochemical analysis techniques. Eighteen male Sprague Dawley rats aged 21days were assigned into control, sham and EMF groups on a random basis. No procedure was performed on the control group rats. The EMF group (EMFGr) was exposed to a 900-MHz EMF for 1h daily from beginning to end of adolescence. The sham group rats were held in the EMF cage but were not exposed to EMF. All rats were sacrificed at 60days of age. Their brains were extracted and halved. The left hemispheres were set aside for biochemical analyses and the right hemispheres were subjected to stereological and histopathological evaluation. Histopathological examination revealed increased numbers of pyknotic neurons with black or dark blue cytoplasm on EMFGr slides stained with cresyl violet. Stereological analyses revealed fewer pyramidal neurons in EMFGr than in the other two groups. Biochemical analyses showed an increase in malondialdehyde and glutathione levels, but a decrease in catalase levels in EMFGr. Our results indicate that oxidative stress-related morphological damage and pyramidal neuron loss may be observed in the rat hippocampus following exposure to 900-MHz EMF throughout the adolescent period.

New Markers in Atherosclerosis: Thrombospondin-2 (THBS-2) and Leukocyte Cell-Derived Chemotaxin-2 (LECT-2); An Immunohistochemical Study.

BACKGROUND Current research investigating the role of THBS2 and LECT-2 in atherogenesis is very limited. Therefore, we designed this study to demonstrate the role of THBS-2 and LECT-2 in atherosclerosis at the tissue level in fresh specimens. MATERIAL AND METHODS A total of 32 patients who underwent coronary bypass surgery were enrolled. Aortic wall punch biopsies were obtained at the site of proximal aortosaphenous bypass graft anastomosis. A specimen of left internal mammarian artery (LiMA) was taken from the segment just proximal to its anastomosis. The aortic tissue is representive of the atherosclerotic tisue, and LiMA tissue is representative of the non-atherosclerotic area. The specimens were painted with CD68 for macrophage, and THBS-2 and LECT-2 antibodies for immunohistochemical staining. RESULTS Aortic THBS-2 levels were significantly lower, whereas aortic LECT-2 levels were significantly higher when compare to LiMA (14.4±9.9 (5-30) and 36.9±13.0 (5-60) p: 0.0001 and 20.3±15.0 (5-60) and 20.8±13,8 (10-30) p: 0.0001, respectively). CD68+ and monocyte level correlated significantly with AHA atherosclerosis grade (p=0.01, r=0.45 and p=0.001, r=0.56, Spearman's test). CD68+ level correlated significantly with LECT-2 levels in atherosclerotic aortic tissue (p=0.026, r=0.392, Spearman's test), whereas aortic TSBN-2 levels were not. CONCLUSIONS The present study has taken the first steps to highlight new markers in atherosclerosis by using immunohistochemical method. The study results suggest that the tissue levels of THBS2 and LECT-2 may correlate with the stage of atherosclerosis.

Maternal exposure to a continuous 900-MHz electromagnetic field provokes neuronal loss and pathological changes in cerebellum of 32-day-old female rat offspring.

Large numbers of people are unknowingly exposed to electromagnetic fields (EMF) from wireless devices. Evidence exists for altered cerebellar development in association with prenatal exposure to EMF. However, insufficient information is still available regarding the effects of exposure to 900 megahertz (MHz) EMF during the prenatal period on subsequent postnatal cerebellar development. This study was planned to investigate the 32-day-old female rat pup cerebellum following exposure to 900MHz EMF during the prenatal period using stereological and histopathological evaluation methods. Pregnant rats were divided into control, sham and EMF groups. Pregnant EMF group (PEMFG) rats were exposed to 900MHz EMF for 1h inside an EMF cage during days 13-21 of pregnancy. Pregnant sham group (PSG) rats were also placed inside the EMF cage during days 13-21 of pregnancy for 1h, but were not exposed to any EMF. No procedure was performed on the pregnant control group (PCG) rats. Newborn control group (CG) rats were obtained from the PCG mothers, newborn sham group (SG) rats from the PSG and newborn EMF group (EMFG) rats from the PEMFG rats. The cerebellums of the newborn female rats were extracted on postnatal day 32. The number of Purkinje cells was estimated stereologically, and histopathological evaluations were also performed on cerebellar sections. Total Purkinje cell numbers calculated using stereological analysis were significantly lower in EMFG compared to CG (p<0.05) and SG (p<0.05). Additionally, some pathological changes such as pyknotic neurons with dark cytoplasm were observed in EMFG sections under light microscopy. In conclusion, our study results show that prenatal exposure to EMF affects the development of Purkinje cells in the female rat cerebellum and that the consequences of this pathological effect persist after the postnatal period.

Morphological and antioxidant impairments in the spinal cord of male offspring rats following exposure to a continuous 900MHz electromagnetic field during early and mid-adolescence.

The effects of devices emitting electromagnetic field (EMF) on human health have become the subject of intense research among scientists due to the rapid increase in their use. Children and adolescents are particularly attracted to the use of devices emitting EMF, such as mobile phones. The aim of this study was therefore to investigate changes in the spinal cords of male rat pups exposed to the effect of 900MHz EMF. The study began with 24 Sprague-Dawley male rats aged 3 weeks. Three groups containing equal numbers of rats were established-control group (CG), sham group (SG) and EMF group (EMFG). EMFG rats were placed inside an EMF cage every day between postnatal days (PD) 21 and 46 and exposed to the effect of 900MHz EMF for 1h. SG rats were kept in the EMF cage for 1h without being exposed to the effect of EMF. At the end of the study, the spinal cords in the upper thoracic region of all rats were removed. Tissues were collected for biochemistry, light microscopy (LM) and transmission electron microscopic (TEM) examination. Biochemistry results revealed significantly increased malondialdehyde and glutathione levels in EMFG compared to CG and SG, while SG and EMFG catalase and superoxide dismutase levels were significantly higher than those in CG. In EMFG, LM revealed atrophy in the spinal cord, vacuolization, myelin thickening and irregularities in the perikarya. TEM revealed marked loss of myelin sheath integrity and invagination into the axon and broad vacuoles in axoplasm. The study results show that biochemical alterations and pathological changes may occur in the spinal cords of male rats following exposure to 900MHz EMF for 1h a day on PD 21-46.

Circadian Rhythm of Infarct Size and Left Ventricular Function Evaluated with Tissue Doppler Echocardiography in ST Elevation Myocardial Infarction.

BACKGROUND: We aimed to investigate the circadian rhythm on left ventricular (LV) function and infarct size, according to the onset of ST elevation myocardial infarction (STEMI), with echocardiography in patients with first STEMI successfully revascularised with primary percutaneous coronary intervention (PCI). METHODS: We conducted a retrospective analysis of 252 STEMI patients. Patients were divided into the four, six-hour periods of the day. Conventional and tissue Doppler imaging (TDI) echocardiography were performed within 48hours after onset of chest pain. The average of peak systolic myocardial velocities (Sm) in each of the four myocardial segments and LV ejection fraction (LVEF) were calculated. RESULTS: A negative linear correlation was shown between CK-MB levels and Sm (r= -0.209, p=0.001). There was an oscillation between time of day and average of Sm. The lowest Sm and largest infarct size were in the period of 06:00-noon compared with period of noon-18:00 and 18:00-midnight (p=0.029 and p=0.031, respectively). A secondary analysis showed that both LVEF and Sm were lower in the midnight-noon group compared with the noon-midnight group (44.9±7.3% versus 47.3±7.9%, p=0.018, and 7.6±1.4cm/s versus 8.2±1.6cm/s, p=0.003, respectively). CONCLUSIONS: This study has shown that there was a circadian rhythm of infarct size and LV function evaluated by echocardiography according to time of STEMI onset. The largest infarct size and poor LV function occurred in the midnight-noon period, in particular in the 06:00-noon period.

Deleterious impacts of a 900-MHz electromagnetic field on hippocampal pyramidal neurons of 8-week-old Sprague Dawley male rats.

Children are at potential risk due to their intense use of mobile phones. We examined 8-week-old rats because this age of the rats is comparable with the preadolescent period in humans. The number of pyramidal neurons in the cornu ammonis of the Sprague Dawley male rat (8-weeks old, weighing 180-250 g) hippocampus following exposure to a 900 MHz (MHz) electromagnetic field (EMF) were examined. The study consisted of control (CN-G), sham exposed (SHM-EG) and EMF exposed (EMF-EG) groups with 6 rats in each. The EMF-EG rats were exposed to 900 MHz EMF (1h/day for 30 days) in an EMF jar. The SHM-EG rats were placed in the EMF jar but not exposed to the EMF (1h/day for 30 days). The CN-G rats were not placed into the exposure jar and were not exposed to the EMF during the study period. All animals were sacrificed at the end of the experiment, and their brains were removed for histopathological and stereological analysis. The number of pyramidal neurons in the cornu ammonis of the hippocampus was estimated on Cresyl violet stained sections of the brain using the optical dissector counting technique. Histopathological evaluations were also performed on these sections. Histopathological observation showed abundant cells with abnormal, black or dark blue cytoplasm and shrunken morphology among the normal pyramidal neurons. The largest lateral ventricles were observed in the EMF-EG sections compared to those from the other groups. Stereological analyses showed that the total number of pyramidal neurons in the cornu ammonis of the EMF-EG rats was significantly lower than those in the CN-G (p<0.05) and the SHM-EG (p<0.05). In conclusion, our results suggest that pyramidal neuron loss and histopathological changes in the cornu ammonis of 8-week-old male rats may be due to the 900-MHz EMF exposure.