2,582 research outputs found

    The effect of Urtica dioica extract on the number of astrocytes in the dentate gyrus of diabetic rats

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    Diabetes mellitus is associated with cerebral alterations in both human and animal models of the disease. These alterations include abnormal expression of hypothalamic neuropeptides and hippocampal astrogliosis. Urtica dioica (Nettle) is among several species listed for their use against diabetes in folk medicine. The aim of this study was the evaluation of the astrocyte number in the dentate gyrus of diabetic rats after treatment with nettle. A total of 21 male albino Wistar rats were used in the present study. The animals were divided into three groups: control, nettle-untreated diabetic, and nettle treated diabetic. Hyperglycaemia was induced by streptozotocin (80 mg/kg) in the animals of the diabetic and treatment groups. One week after injection of the streptozotocin, the animals in the treatment group received a hydroalcoholic extract of Urtica dioica (100 mg/kg/day) for 4 weeks intraperitoneally. After a 5-week survival period, all the rats were sacrificed and coronal sections were taken from the dorsal hippocampal formation of the right cerebral hemispheres. The area densities of the astrocytes were measured and compared between the three groups (p < 0.05). The number of astrocytes increased in the diabetic rats (24.06 ± 9.57) compared with the controls (17.52 ± 6.66). The densities in the treated rats (19.50 ± 6.16) were lower than in the diabetic rats. Furthermore, the control and treated rats showed similar densities. We concluded that U. dioica extract helped compensate for astrocytes in the treatment rats dentate gyrus in comparison with diabetic rats. Copyright © 2009 Via Medica

    Epidemiologic aspects of neural tube defects in South East Iran

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    Objectives: To investigate the rate of neural tube defects (NTDs) and their relation to gender, maternal age, consanguineous marriage, season, and drug consumption in Birjand, Iran. Methods: This research was carried out on 16,785 live or stillborn newborns in Birjand, Iran from April 1997 to December 2001. Results: The rate of NTDs was 2.97 per 1000. This rate was 1.97 per 1000 in males, and 3.55 per 1000 in females. The rate of anencephaly was 1.37 per 1000, and spina bifida was 0.88 per 1000. We found that 32% of mothers with affected newborns had taken drugs during the first trimester of pregnancy, 90% of mothers did not consume folate before and during the first trimester, and 54% of parents had consanguineous marriage. Conclusion: We concluded that folate deficiency, usage of drugs during pregnancy, and consanguineous marriage may play a role of predisposition to NTD

    The preventive and treatment effect of Urtica dioica on astrocyte density in the CA1 and CA3 subfields of hippocampus in STZ induced diabetic rats

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    Several animal model studies have shown that Diabetes mellitus can affect on the activity of hippocampus astrocytes, but these studies reported controversial findings. This study was done to evaluate the preventive and treatment effect of Urtica dioica (U. dioica) on astrocytes density in the CA1 and CA3 subfields of hippocampus of streptozotocin (STZ) induced diabetic rats. Twenty-eight male albino Wistar rats were randomly allocated equally into control, diabetic, U. dioica treatment and U. dioica preventive groups. Hyperglycemia was induced by STZ (80 mg/kg/BW). One week after injection of the streptozotocin, animals in treatment group were received hydroalcoholic extract of U. dioica (100 mg/kg/BW /day) for 4 weeks by intraperitoneally. In preventive group, diabetic rats were received 100 mg/kg/BW/ daily hydroalcoholic extract of U. dioica for 5 days before STZ injection. Then, animals were sacrificed and coronal sections were taken from the right dorsal hippocampus, stained with PTAH. The area densities of the astrocytes were measured. The number of astrocytes in CA1 of controls, diabetic treatment and preventive groups was 19.00±5.5, 17.14±6.4, 21±8.1 and 16.48±3.2, respectively. The densities of astrocytes in CA3 of controls, diabetic, treatment and preventive groups were 25.45±7.60, 21.54±7.5, 23.75±5.6 and 19.89±3.8, respectively. The density of astrocytes in diabetic rats reduced in comparison with controls (P<0.05). In CA1 and CA3, in spite of preventive administration, treatment of diabetic rats with U. dioica significantly increased the astrocytes. This study showed that treatment with U. dioica extract can help compensate for the CA1 and CA3 subfields of hippocampus astrocytes in diabetic rats

    String Memory Effect

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    In systems with local gauge symmetries, the memory effect corresponds to traces inscribed on a suitable probe when a pure gauge configuration at infinite past dynamically evolves to another pure gauge configuration at infinite future. In this work, we study the memory effect of 2-form gauge fields which is probed by strings. We discuss the "string memory effect" for closed and open strings at classical and quantum levels. The closed string memory is encoded in the internal excited modes of the string, and in the open string case, it is encoded in the relative position of the two endpoints and the noncommutativity parameter associated with the D-brane where the open string endpoints are attached. We also discuss 2-form memory with D-brane probes using boundary state formulation and, the relation between string memory and 2-form soft charges analyzed in [1]

    Compressed Sensing based Dynamic PSD Map Construction in Cognitive Radio Networks

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    In the context of spectrum sensing in cognitive radio networks, collaborative spectrum sensing has been proposed as a way to overcome multipath and shadowing, and hence increasing the reliability of the sensing. Due to the high amount of information to be transmitted, a dynamic compressive sensing approach is proposed to map the PSD estimate to a sparse domain which is then transmitted to the fusion center. In this regard, CRs send a compressed version of their estimated PSD to the fusion center, whose job is to reconstruct the PSD estimates of the CRs, fuse them, and make a global decision on the availability of the spectrum in space and frequency domains at a given time. The proposed compressive sensing based method considers the dynamic nature of the PSD map, and uses this dynamicity in order to decrease the amount of data needed to be transmitted between CR sensors’ and the fusion center. By using the proposed method, an acceptable PSD map for cognitive radio purposes can be achieved by only 20 % of full data transmission between sensors and master node. Also, simulation results show the robustness of the proposed method against the channel variations, diverse compression ratios and processing times in comparison with static methods
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