Showing 173 results for Rat
Gholamreza Najafi, Rahim Hobe Naghi, Aref Hoshyari, Masoud Moghadaszadeh, Behzad Ghorbanzadeh,
Volume 15, Issue 10 (3-2013)
Abstract
Background: Atrazine is an herbicide used widely by farmers in controlling weeds. The aim of this investigation was to evaluate the effect of atrazine, as an herbicide, on sperm quality, sperm DNA damage, invitrofertilization (IVF), and embryonic development in mature male rats. Materials and Methods: In this experimental study, 42 mature male Wistar rats weighing 170±5g were divided into three groups, including one control and two treatment groups. The rats in the control group were administered corn oil (0.2 ml/day) and the rats in the test groups were orally gavaged with atrazine 150mg/kg (high dose) and 75mg/kg (low dose) body weight daily for a total of 45 days. Epidydimis tail was cut and placed in 1 ml of human tubular fluid (HTF) medium for 30 minutes in an atmosphere of 5% CO2 in air at 370C. The sperms were analyzed for sperm count, sperm viability, motility, DNA damage, immature sperm, and in vitro fertilization. Data were analyzed by One-Way ANOVA. Results: In this study, atrazine provoked a significant decrease (P<0.05) in sperm number, sperm viability, and sperm motility. The data suggest that the atrazine had a negative impact on sperm maturation and DNA integrity in a time-dependent manner, which consequently caused a significantly remarkable reduction in IVF ability (P<0.05). Conclusion: Atrazine is capable of inducing DNA damage and chromatin abnormalities of spermatozoa which can contribute to a low fertilization rate.
Kazem Biabani, Ahmad Zare, Hamid Kohram, Mehdi Khodaeimotlagh,
Volume 15, Issue 10 (3-2013)
Abstract
Background: Heat stress reduces reproductive performance in farm animals. The aim of this study was to determine the effect of heat stress and different concentrations of melatonin on nuclear maturation of ovine oocytes. Materials and Methods: In this experimental study, ovary collection and oocyte recovery were carried out by standard methods. Oocytes culture was in A: TCM199+10% FBS, 5µg/ml FSH, 0.01IU/ml LH, 100 IU/ml penicillin, and 100 IU/ml streptomycin, B: A+heat stress at 40 C0, and C and D:B+1 and 10 µM melatonin, respectively. Results: Heat stress significantly (P<0.05) decreased nuclear maturation in the treatment group in comparison with the control group (60.60 vs. 84.89). Also, 1 and 10 µM melatonin could improve oocytes to reach metaphase-II stage (60.60 vs. 76.92, 78.82, respectively). However, increasing the melatonin dose from 1 to 10 µM did not alter oocytes maturation. Conclusion: Overall, this study showed that melatonin improves ovine immature oocytes maturation during heat stress.
Mahin Farahmand, Amir Almasi-Hashiani, Davood Mehrabani,
Volume 15, Issue 10 (3-2013)
Abstract
Background: Prostate cancer is one of the most common cancers in men which its incidence rate and associated mortality and morbidity are on the rise. The aim of this study was to investigate the epidemiology of prostate cancer in Fars province between 2003 and 2008 years. Materials and Methods: In this epidemiological study, using Fars province cancer registry data, the incidence rates were calculated per 100,000 people and age standardized incidence rate (ASR) was measured by direct method using the world standard population. Data were analyzed by SPSS, version 16, and Microsoft Excel, version 2007. Cochrane Armitage Test for linear trend was used for evaluation of the incidence trend by running Winpepi software. Results: Over a 6-year period, 1212 cases were recorded in Fars province. The ASR of prostate cancer in these six years was 4.69, 7.16, 15.09, 14.04, 16.65 and 16.02, respectively, which revealed significantly increasing trends. The highest incidence rate was observed in 80 and upper age group. Conclusion: The ASR of prostate cancer in Fars province is significantly lower than other parts of the world, especially in more developed countries. This can be due to absence of screening programs and/or cancer registry.
Narjes Najibi, Ahmad Reza Dorosty Motlagh, Haleh Sadrzadeh Yeganeh, Mohammad Reza Eshraghian, Milad Daneshi, Samaneh Azizi,
Volume 16, Issue 1 (4-2013)
Abstract
Background: Food insecurity is defined as the limited or uncertain availability of enough food for an always active and healthy life. Diabetes mellitus, one of the most common metabolic diseases, has been associated with significant morbidity and mortality and it is considered a health priority in Iran. Recent studies indicate the widespread prevalence of food insecurity and diabetes mellitus in Iranian society. This study reviews the status of food insecurity and effective socio-economic factors in people with type 2 diabetes.
Materials and Methods: This cross-sectional study was performed on 135 patients, aged between 30 and 55, who had recently been diagnosed with type 2 diabetes. Demographic and socioeconomic characteristics and food insecurity status were assessed using demographic and the 18-item USDA household food security questionnaires, respectively. Physical activity also was evaluated by MET, physical activity questionnaire. Data were analyzed by Chi-square, t-test, and logistic regression.
Results: Prevalence of food insecurity was 66.7%. Food insecurity was significantly associated with economic status, education level, income, having child under 18 years of age, family size, and number of children (p<0.05) however, there was not a significant relationship between food insecurity and occupation, marital status, family history of diabetes, high blood pressure and heart disease, age, and the amount of physical activity.
Conclusion: Considering the higher prevalence of food insecurity in diabetic patients, it can be said that it is likely that the incidence of diabetes is higher in food insecure people.
Mahboobe Ferdosi Makan, Jina Khayatzade, Maryam Tehranipoor, Morteza Behnam Rasooli,
Volume 16, Issue 1 (4-2013)
Abstract
Background: Peripheral nervous system damages reverse as retrograde to alpha neuron cell bodies and cause spinal degeneration. The fact that herbs, due to their antioxidant properties, have an important role in viability and reproduction of neurons has led to the application of their extracts. Hence, this study was done to determine the neuro-protective effects of the hydroalcoholic extract of Nigella sativa on alpha-motoneurons degeneration after sciatic nerve injury in rats.
Materials and Methods: In this experimental study, 24 male Wistar rats with average bodyweight of 250-300gr were divided into four groups of six: Control, compression, A (compression+hydroalcoholic extract 50 mg/kg), and B (compression+hydroalcoholic extract 75 mg/kg). In compression and treatment groups, the right leg sciatic nerve was subjected to compression (30 seconds). In treatment groups, the extract was injected intraperitoneally two times after compression. After 28 days, lumbar segments of spinal cord, L2-L4, were sampled through perfusion method. After going through tissue passage stages, they were cut in serial sections (7µ) and stained with toluidine blue. Then the density of alpha motoneurons of the spinal cord ventral horn was measured by dissector method.
Results: Neuronal density showed a significant difference between the compression and control groups (p<0.05). Also, in treatment groups A and B, it had a significant increase compared to the compression group (p<0.05).
Conclusion: The results indicated that the hydroalcoholic extract of Nigella sativa has neuro-protective effects and the increase in neuronal density is relevant to the amount of extract used.
Fatemeh Baghebani, Javad Heravian, Akbar Derakhshan, Mohammad Khajedaluee, Abbas Azimi , Hadi Ostadi Moghaddam, Abbasail Yekta ,
Volume 16, Issue 6 (9-2013)
Abstract
Background: The aim of this study was to determine the prognosis of visual acuity and contrast sensitivity in keratoconus patients according to the correlation between aberrations changes before and after RGP lenses.
Materials and Methods: A total of 40 eyes of twenty patients 20 to 40 years with mild, moderate keratoconus were participated in this study. Ocular examinations were included VA with standard Snellen chart, CS with CSV 1000 chart and HOAs with technolas aberrometer objective (Bush & Luamb). All these tests were performed before and after RGP lenses. Refraction and corneal radius of curvature were measured using Autokeratometr. Data were then analyzed with Spss softwair version 11.5.
Results: Mean contrast sensitivity at each spatial frequency with RGP lenses was higher than the best correction in both male and female. Compairing with best correction mean high order aberration of the 5 and 6 mm pupil was reduced with RGP lenses but the effect was not statistically significant different. Mean high order aberration with pupil 6 mm was more than pupil 5 mm. Using Pearson correlation test, there was no significant correlation between visual change and Contrast sensitivity changes with high order aberrations.
Conclusion: Visual performances and visual acuity were improved with RGP lens than best correction by reduction of high-order aberrations. However, there was no correlation or relationship between high order aberrations and visual performance. This indicates that Aberrometery condition was unrelated with Prediction of visual acuity changes in this patients.
Atefeh Babaei, Javad Arshami, Ali Reza Haghparast, Mohsen Danesh Mesgaran,
Volume 16, Issue 6 (9-2013)
Abstract
Background: Saffron (Crocus Sativus) petals consist of, glycosides, flavonoids, and anthocyanins. Due to the increasing use of medicinal plants in treatment of diseases and identifying their side effects on various organs, this study is to evaluate the effects of Crocus Sativus petals on biochemical blood parameters in male rats.
Materials and Methods: In this experimental study, 30 male Wistar rats with the mean body weight of 215±15 g were randomly assigned into five groups of 6 animals each. Control group received normal saline (10 ml/kg) and treatment groups received 75, 150, 220 and 450 mg/kg body weight of saffron petals extract, for 14 days. Body weight measured in days 0, 7, and 14. At the end of experiment, serum levels of liver function marker enzymes such as AST and ALT, total proteins, albumin, creatinine, cholesterol and triglyceride were assessed.
Results: Compared to control group, ethanol extract of saffron petals significantly increased serum albumin and also significantly decreased levels of serum cholesterol and AST (p<0.05). No significant changes were observed on serum total proteins, creatinine, ALT, triglyceride levels and body weight in control and saffron groups (p>0.05).
Conclusion: Increase in levels of albumin and decrease in liver enzymes may indicate the lack of liver damage. Reduction in cholesterol which is probably due to flavonoid extracts of saffron and no effect on body weight can be beneficial in the use of saffron petals.
Saeid Babaei, Reza Talebi, Mohammad Reza Darabi, Mahmood Reza Nakhaei, Mohammad Bayat, Parvindokht Bayat, Maryam Ba Azm,
Volume 16, Issue 8 (11-2013)
Abstract
Background: Pentoxifylline is a xantin derivative that causes deduction of blood viscosity, improves peripheral blood current and increases tissues oxygenization. In this study, considering special properties of this drug and inspite of undefined mechanism of its effect, the effect of pentoxifylline on skin biomechanical indices in acute phase of skin wound healing in rat is evaluated.
Materials and Methods: In this experimental study 14 adult Wistar rat were divided in two groups of experimental (n=7) receiving 100mg/kg twice a day and control (n=7) receiving distilled water intraperitoneal. Incisional wounds, 20mm length in identical pattern were created on back skin of rats. On day 15 skin strips containing incision were excised and used to evaluate biomechanical indices, work up to maximum force-Nm and Tensile strength= Rm-N/mm2. Results were analyzed by Spss soft ware and K-S, Levens and student T-Test.
Results: According to biomechanical test findings, pentoxifylline administration causes improvement in biomechanical indices of skin after 15 days of drug administration. Discrepancy between skin biomechanical indices of experimental and control subgroups was significant (p<0.05).
Conclusion: Pentoxifylline caused improvement in skin biomechanical indices and accelerated skin wound healing in experimentals.
Fatemeh Safi, Hormoz Haddad Larijani, Mehri Jamilian, Bahman Sadeghi,
Volume 16, Issue 9 (12-2013)
Abstract
Background: Today, ultrasonography has become the main tool used for the evaluation of fetal anomalies. The aim of this study was to evaluate fetal heart rate changes immediately after combined two- and 4-dimensional ultrasound.
Materials and Methods: This study was performed on 191 pregnant women aged 15 to 45 years old who were referred for 4-dimensional ultrasonography in summer 2013. Before the onset of 2-dimensional ultrasonography, baseline fetal heart rate was measured by ultrasound. At the same time, the maternal heart rate was recorded during one minute. Then, combined ultrasonography was performed and same parameters were recorded at the end.
Results: Maternal heart rate significantly decreased after combined ultrasonography (p=0.0001). Fetal heart rate did not differ before and after ultrasonography (p=0.693).
Conclusion: Four-dimensional ultrasonography has no effect on fetal heart as an indicator for evaluating the fetus temperature.
Somaye Ghaderi, Fatemeh Alaee Karahrudi , Parsa Yousefi Chaijan , Navideh Nasiri Oscui ,
Volume 16, Issue 10 (1-2014)
Abstract
Background: Hospitalization of a child in pediatric intensive care unit (PICU) is a very stressful experience for parents. High stress in father can product decline in psychological adaptation and associated problems. The present study aimed to determine effect of fathersʼ participation in the care of hospitalized child in PICU on fathersʼ stress and coping strategies.
Materials and Methods: This is a clinical trial with 60 fathers with children admitted to the PICU in intervention and control groups. Fathers in intervention group, participated in the care of the child in 5 times, during a 5-days course. Fathersʼ stress and coping strategies were surveyed in intervention group before and after participation course and in control group before and after a 5-days course.
Results: Fathersʼ stress in intervention group decreased significantly after participation (p˂0.001) but in control group difference was not significant after time course. Fathers in both groups applied similar coping strategies that majority were emotion focused.
Conclusion: Fathers having children in PICU would experience a lot of stress. Their participation in the care of the children would be very effective to decline their stress and reach most adaptation with disease, cure and cares in children.
Zahra Fazeli, Mahbobe Najafian Zade, Babak Eshtati, Amir Almasi Hashiani,
Volume 16, Issue 11 (2-2014)
Abstract
Background: The prevalence and incidence of cancer in different parts of the world have different patterns. To recognize the frequency of malignancies in different social groups according to climatic conditions is considered as the primary component of prevention programs at different levels. This study was conducted to investigate the epidemiology, survival rates and geographical epidemiology of breast cancer in Markazi province.
Materials and Methods: In this epidemiological study, needed data were obtained from cancer registration program and death registration data. The data were analyzed by using SPSS software version 16 and Winpepi and significant level was 0.05. And to draw a map to show the breast cancer incidence rate in Markazi district, Arc view software was used.
Results: Out of the 400 cases recorded during the 5-year, 8.5% died due to breast cancer. 5-year survival rate was 87% and there was a significant correlation between survival rate and age. Most records were related to the age group 49-40 years and the highest incidence rate was in Arak. The trends of incidence rate was not significant.
Conclusion: The results showed that 5-year breast cancer survival rate is more than some other places which could be due to new and improved methods of treatment and methods of screening and early detection of disease. Other aspects of the epidemiology of the disease is similar to other parts of Iran.
Bahareh Jalalvandi, Parichehr Hanachy, Parvaneh Nazarali, Saeed Naghibi,
Volume 17, Issue 1 (4-2014)
Abstract
Background: In recent years, studies have been conducted on the role of coenzyme Q10 in improvement of sport performance and also cardiovascular health. The present study investigate effect of coenzyme Q10 supplementation combined with swimming aerobic exercises on Heart Rate Deflection Point (HRDP) and VO2max in active women.
Materials and Methods: A number of 32 trained women with the average age of 21/25 ± 0.86 years and Body Mass Index (BMI) of 20/127± 1.06 kg/square meter were selected randomly and were divided into eight -member each groups: Control, Supplement, Supplement – Exercise and Exercise. The subjects participated in four-week consumption of coenzyme Q10 and swimming exercises (three sessions in a week).The consumption rate of coenzyme Q10 100 mg/kg/d was in the form of capsule that subjects took it during lunchtime. Before and after a four-week period, the subjects performed an incremental exhaustive test on treadmill, using respiratory gas analyzer to determine HRDP and VO2max. It should be noted that data analysis was conducted using One-Way Variance Analysis Test (ANOVA) in P<0.05 significant level.
Results: Based on paired T-Test results, despite HRDP had increased in each four groups but the significant increase was observed only among groups in VO2max (P=0.008) based on ANOVA Test (P<0.05).
Conclusion: Although positive changes were observed inside the group after passage of four weeks, coenzyme Q10 supplementation combined with swimming aerobic exercise had not any significant effect on HRDP only increased VO2max.
Fatemeh Shima Hadipourzadeh, Hamid Kaialha, Firoozeh Naderi,
Volume 17, Issue 1 (4-2014)
Abstract
Background: Intrathecal morphine side effect is Nausea & Vomiting after surgery. The aim of the study was to evaluate the effect of intrathecal atropine on PONV in patients receiving intrathecal morphine in lower limb surgeries.
Materials and Methods: In this clinical trial , 120 patients undergoing lower limb surgery were randomly divided into 2 groups . Experimental group received 0.1 mg (1cc) Intrathecal atropine and control group received 1cc saline 0.9% . PONV during the first 24 hours and hemodynamic changes in minute 3, 5, 10 and 15 after surgery in both groups were measured. Data were analyzed using SPSS software (verision14). independent t-test, repeated measures manova,and chi-square were used to compare comparison of variables.
Results: Hemodynamic cheanges before injection and 3, 5, 10 and 15 after injection in two groups was not significant (P>0.05). None of the patients in the intervention group were PONV, but 17 patients in the control group had PONV that this difference was statistically significant (p =0.000 ). Pain in the control group was great than intervention group while 26 patients in the control group and 14 patients in the intervention group had vas greater than 3 that this difference was statistically significant( P = 0.04).
Conclusion: Intrathecal atropine without interfering Hemodynamic and pain relief prevent nausea and vomiting caused by Intrathecal morphine in patients undergoing surgery to the lower limbs..
Seyyedeh Sara Hashemi, Gholam Ali Jelodar, Alireza Rafati,
Volume 17, Issue 2 (5-2014)
Abstract
Background: Fluoxetine or Prozac is a serotonin reuptake inhibitor (SSRI). Considering the importance of this drug for the treatment of neurological disorder, such as anorexia and depression its side effects on the endocrine axis of body are of significance. Hence, the present study was conducted to evaluate the effects of fluoxetine on cortisol and thyroid hormone levels and body weight in male rates.
Materials and Methods: In this experimental study, 30 adult male rats (230±20 gr BW) were randomly divided into 3 equal groups: sham, control and treatment. Rats in the control group were kept in normal conditions in animal house, whereas treatment and sham groups were, respectively, injected 32 mg/kg BW of fluoxetine and 0.9 ml of normal saline (i.p) for 35 days. During this time, body weight of all animal was measured and after 35 days, blood was collected by heart puncture and separation of serums to evaluate T3, T4, fT3, fT4, and cortisol hormones through RIA method. The results were statisticaly evaluated by one-way ANOVA test.
Results: Taking fluoxetine for 35 days significantly decreased the level (p&le0.05) in serum concentrations of Ft3, fT4, T4 and cortisol hormones compared to the control and sham groups. However, no significant differences were observed in the serum concentration of T3 hormone in treatment group compared to the the control group. The drug also caused a significant decrease in the average weight of rats in the treatment group compared to the control group (p&le 0.05).
Conclusion: By affecting the activity of different levels of hypothalamus-pituitary-adrenal hormones axis, fluoxetin decreases the level of cortisol hormones. It also reduces the activity of the thyroid gland this is probably due to the increased prolactin secretion through inhibiting TRH secretion and reducing the production of TSH and thyroid hormones
Ali Asgar Yaghoubi, Ali Sirus, Mahmoud Amini, Ali Shojaei, Saeid Haj Hashemi, Fatemeh Olyen Feeni , Mojtaba Ahmadlou,
Volume 17, Issue 4 (7-2014)
Abstract
Background: Peripheral nerve injures are common in clinical practice that includes from compression injury to complete disruption of nerve trunk. After injury nerves can grow and repair spontaneously, early end to end anastomosis is first choice for repair but only 50% of nerve fiber would be physiologically accurate and effective, thus several techniques for repair of nerve injury are introduced including combination of nerve transplant with silicon tubes, use of biologic and synthetic tubes for nerve conduit.
Materials and Methods: In this Exprimental study, 20 rats with the same weight were selected and kept in the same condition .The left sciatic nerve of them was cut and were divided in two groups.In the first group the facial flap method for repair of nerve injury was used .In the second group vein conduit method was used as standard method. Histological nerve repair was assessed after 45 days and the intact right sciatic nerve was used as control.
Results: Repair of nerve injury in proximal, mid and distal portion of nerve in facial flap method was more effective than vein conduit (P<0.05). Repair of nerve injury in proximal, mid and distal portion had no difference compared with control group (p>0.05).
Conclusion: Repair of nerve injury with facial flap method is more effective than standard method and can be used as a new method for nerve repair.
Sepideh Mortaji, Anousheh Haghighi, Farzad Pakdel,
Volume 17, Issue 5 (8-2014)
Abstract
Background: Rheumatoid arthritis is the most common inflammatory arthritis. Keratoconjunctivitis sicca, scleritis, and episcleritis are ocular complications of this disease. The aim of this study is to evaluate Sjogren’s syndrome in subjects with rheumatoid arthritis.
Materials and Methods: In this cross-sectional study, ninety patients diagnosed as rheumatoid arthritis that followed up in rheumatology clinic of Rasool Akram hospital for six months and no definite cause was found for their dry eye, enrolled in the study. Rheumatoid arthritis activity was evaluated by DAS28 index and the severity of dry eye was assessed by Japanese dry eye diagnostic criteria.
Results: Mean activity of disease according to DAS28 was 2.9±1.56 and 88.9% of patients had dry eye based on Japanese dry eye diagnostic criteria. Twelve patients (13.3%) had secondary Sjogren's syndrome. SSA antibody was positive in 13.3% patients and 10% patients had positive SSB antibody. There was significant correlation between rheumatoid arthritis activity based on DAS28 and severity of dry eye according to Japanese dry eye diagnostic criteria in the both Sjogren (p=0.045) and non Sjogren groups (p=0.001).
Conclusion: We found significant correlation between rheumatoid arthritis activity and dry eye in the both sjogren and non-Sjogren groups. Most of rheumatoid arthritis subjects do not have Sjogren’s syndrome but dry eye is common even in rheumatoid arthritis patients without Sjogren's syndrome.
Saeid Babaei, Mohammad Reza Darabi, Mohammad Bayat, Mahmood Reza Nakhaei, Parvindokht Bayat, Maryam Ba Azm, Mina Ghadamian, Soheila Bana Sadegh,
Volume 17, Issue 7 (10-2014)
Abstract
Background: It is expected that affected people with diabetes will increase to 439 million in 2030, 15% of them are affected with chronic leg ulcer disease. Increasing number of researches implicate the positive influence of pentoxifylline (PTX) on the skin wound healing. Pentoxifylline is a xantin derivative that modifies or inhibits inflammatory factors, reduces blood viscosity, improves peripheral blood currency and increases oxygenation of tissues the In this study the effect of Pentoxifylline (PTX) on skin biomechanical indices in acute phase of skin wound healing in diabetic rat is in considerable interest.
Materials and Methods: It is an experimental- interventional study in which fourteen adult male wistar rats were divided into experimental group (n=7), receiving pentoxifyllineintraperitoneally and control group (n=7) receiving distilled water (DW). Diabeteswas induced by intraperitoneal administration of streptozotocin in both groups then full thickness incisional wound (20mm length) in identical pattern was made on the dorsum of rats. After 15 days a band of skin (4×60mm) containing wound was extracted and used to evaluate skin biomechanical indexes (work up to maximum force-Nm and Tensile strength= Rm-N/mm2). Results were analysed by SPSS software version 19 and K-S, Levens Test and Student SampleT-Test were used.
Results: Pentoxifylline administration improved skin biomechanical indices after 15 days after skin incisional wound. Differences between experimental and control’s indices were significant (p<0.05).
Conclusion: Pentoxifylline accelerated wound healing and improved tensile strength of skin in diabetic rats of experimental group.
Bakhtyar Tartibian, Bahman Ebrahimi Turkmani,
Volume 17, Issue 7 (10-2014)
Abstract
Background: The aim of this research was to determine the relationship between inflammatory markers (Fibrinogen, C-reactive protein (CRP) and Creatine kinase (CK)) and respiratory responses FEF25-75% (Forced expiratory flow in 25-75 percent) and FEV1 (Forced expiratory volume in one second) in 14-16 year’s Urmia city boys in response to an incremental physical activity.
Materials and Methods: The subjects were boys of 14-16 years among 24 healthy participants. These groups divided into two groups randomly, one group as trained one (n=12) and the othes as control group. Blood sample was taken in baseline and after Modified Balke Protocol in trained group, And the blood sampling was taken in baseline and 48 hours later in control group. respiratory responses were measured immediately after Modified Balke Protocol.
Results: CRP and Fibrinogen significantly increased in trained group (p<0.001) and this group had high level of these markers compared with control group (p<0.001). The association between CRP with FEF25-75% and fibrinogen with FEF %25-75 and CK with FEF 25-75% in trained group was significant (p&le0.05).
Conclusion: The results of this study show that incremental physical activity increased inflammatory factors in active children. Incremental exercise shows a strong relationship between some inflammatory markers and respiratory parameters in adolescents 14-16 years old.
Mohammad Reza Dayer, Nooshin Azari, Nematollah Razmi, Mohammad Saeid Dayer,
Volume 17, Issue 7 (10-2014)
Abstract
Background: Prion diseases are neurodegenerative disorders which ultimately results in the death of their victims. They are caused by structural transformation of cellular prion (PrPC) to its &beta-rich and anomalous isoform (PrPSc) and the accumulation of amyloid fibrillar deposits in the central nervous system. The precise mechanism underling this conversion is yet to be well understood. This study aimed to investigate the effect of non physiological temperatures on the misfolding mechanism of the human prion protein.
Materials and Methods: The crystal structure of human prion protein (90-231), (PDB code: 2Lej) in pdb format was used as a starting structure in this study. Three model structures of this coordinate structure were used separately to simulate PrPC at 27 , 37 and 47 . Molecular dynamic simulations were then performed using double-precision MPI version of GROMACS 4.5.5 for 10 ns and the results were analyzed using SPSS software, SPDBV and VebLab programs.
Results: The change of temperature from 37 to 27 or 47 induced significant structural changes to PrPC. These tempratures caused PrPC to attain a more folded and less flexible tertiary structure compared to its native structure at 37 . They, also, reduce protein-solvent hydrogen bonds and therefore increasing access of hydrophobic solvent to PrPC which may be behind the lower water solubility of PrPC and its increased resistance to proteolytic degradations.
Conclusion: This study shows that changes of temperatures accelerate structural changes of PrPC and reduce its solubility while rendering it vulnerable to transition into PrPSc.
Sayyed Alireza Talaei, Mahmoud Salami, Sayyed Mojtaba Banitaba,
Volume 17, Issue 7 (10-2014)
Abstract
Background: Environmental signals have a crucial role in development of brain’s structure and function during critical period of brain development. Gt was valuated the devebpmental effeck in developmental effect of visual deprivation on synaptic plasticity of Dentate Gyrus neurons was evaluated.
Materials and Methods: This experimental study was carried on 2 groups (n=48) rats kept in standard 12-hour light/dark condition (Light Reared-LR) or in complete darkness (Dark Reared-DR) since birth throughout the study. Each group, in turn, was divided into 3 groups of 2, 6 and 10 weeks old subgroup (n=8 for each). Stimulating the perforant path, field potentials were recorded in the Dentate Gyrus area for 30 minutes. Then, the tetanic stimulation was applied to the Schaffer collaterals and the field potentials were pooled for 120 minutes post-tetanus in all animals.
Results: The basic responses of the LR animals decreased and the amplitude of the DR rats increased, across aging. After the LTP induction, amplitude of responses increased in all groups but the amount and stability of them were lower dark reared in animals than the LR ones.
Conclusion: Change in environmental visual signals impairs basic response and LTP induction in neurons of Dentate Gyrus area of hippocampus.