Effect of scopolamine-based amnesia on the number of astrocytes in the rat's hippocampus

As neuron-astrocyte interactions play a crucial role in the adult brain, it is thought that astrocytes support learning and memory through specific mechanisms. In this study, the effect of scopolamine based amnesia on the number of astrocytes in rats' hippocampus was studied. Adult male albino Wistar rats were bilaterally cannulated into the CA1 region and animals received saline or different doses of scopolamine (0.5, 1 and 2 mg/ rat, intra - CA1), immediately after training. Then all the rats were sacrificed and coronal sections were taken from the dorsal hippocampal formation of the right cerebral hemispheres and stained with PTAH. The area densities of the astrocytes in dentate gyrus were measured and compared in the all groups (p < 0.05). Data showed that post-training scopolamine (0.5, 1 and 2 μg/rat, intra-CA1) dose-dependently reduced the step-through latency in the inhibitory avoidance task, showing scopolamineinduced amnesia. Also we found different response of astrocytes in different subfields of hippocampal formation. In dentate gyrus the number of astrocytes was increased, but in other areas scopolamine can decreased the density of astrocytes. We concluded that scopolamine can cause amnesia and this phenomenon can have an effect on astrocyte numbers in the rats hippocampal formation

Gamma radiation-induced impairment of hippocampal neurogenesis, comparison of single and fractionated dose regimens Deterioro de la neurogénesis en el hipocampo inducida por radiación gamma, comparación de los regímenes de dosis única y fraccionada

Radiation therapy of the brain is associated with many consequences, including cognitive disorders. Pathogenesis of radiation induced cognitive disorder is not clear, but reduction of neurogenesis in hippocampus may be an underlying reason. 24 adult male rats entered to study. Radiation absorbed dose to midbrain was 10 Gy, delivered by routine cobalt radiotherapy machine which its output was measured 115.24 cGy/min. The rats were divided in four groups of sixes, including groups of control, single fraction 10 Gy, fractionated 10 Gy and finally anaesthesia sham group. Number of pyramidal nerve cells was counted in two regions of hippocampus formation (CA1 and CA3). The radiation could reduce the number of cells in two regions of hippocampus significantly (p=0.000). It seems fractionated 10 Gy irradiation to more efficient than single fraction, while role of anaesthesia drug should be cautiously assessed. Moreover the rate of neurogenesis reduction was determined the same in these regions of hippocampus meaning the same radiosensitivity of cells

Radiation-induced lowered neurogenesis associated with shortened latency of inhibitory avoidance memory response

The neural system is less sensitive to radiation than other late-responding organs and tissues such as the kidney and lung. The generation of new neurons in the adult mammalian brain has been documented in several works. Many studies show that adult hippocampal neurogenesis relates to hippocampal function, in several ways. In this study, we assessed the effect of single and fractionated cobalt radiation on neurogenesis in the dentate gyrus of the hippocampal formation. The irradiation time for delivering 2 Gy (for fractionated dose radiation) and 10 Gy (for single dose radiation) at maximum depth were respectively 1.98 min and 9.92 min. To study the association with memory function we examined inhibitory avoidance memory using a step-through device. Brains were withdrawn and fixed, and then sections were stained with cresyl violet for neurons. We found that a 10 Gy dose can induce lower neurogenesis in the dentate gyrus of the hippocampus (p < 0.05), in such a way that a fractionated dose (5 fractions of 2 Gy) is more effective than a single dose (one fraction of 10 Gy). Moreover, a fractionated dose could reduce step-through latency corresponding to damaged inhibitory avoidance memory (p < 0.05). Synergic action of an anaesthetic drug may be the cause of more reduction of neurogenesis in fractionated irradiated rats. There was no significant difference in latency of the inhibitory avoidance memory response between the single 10 Gy group and the sham group, while fractionated 10 Gy could reduce latency. Different mechanisms of action in the two regimens of irradiation may be a reason

The role of CA1 α-adrenoceptor on scopolamine induced memory impairment in male rats

Introduction: Similarities in the memory impairment between Alzheimer patients and scopolamine treated animals have been reported. In the present study, the possible role of α-adrenergic receptors of the dorsal hippocampus on scopolamine state-dependent memory in adult male Wistar rats was evaluated. Methods: The animals were bilaterally implanted with chronic cannulae in the CA1 regions of the dorsal hippocampus, trained in a step-through type inhibitory avoidance task, and tested 24 h after training to measure step-through latency. Results: Post-training intra-CA1 administration of scopolamine (0.5 and 2μg/rat) dose-dependently reduced the step-through latency, showing an amnestic response. Amnesia produced by post-training scopolamine (2 μg/rat) was reversed by pre-test administration of the scopolamine (0.5 and 2 μg/rat) that is due to a state-dependent effect. Pre-test intra-CA1 injection of α1-adrenoceptor agonist, phenylephrine (0.25, 0.5 μg/rat) in the dose range that we used, could not affect memory impairment induced by post-training injection of scopolamine (2 μg/rat). However intra-CA1 pretest injection of α2-adrenoceptor agonist, clonidine (0.5 μg/rat) improved post-training scopolamine (2 μg/rat) intra-CA1 injection induced retrieval impairment. Furthermore, pre-test intra-CA1 microinjection of phenylephrine (0.25 and 0.5 μg/rat) or clonidine (0.25 and 0.5 μg/rat) with an ineffective dose of scopolamine (0.25 μg/rat), synergistically improved memory performance impaired by post-training scopolamine (2 μg/rat). Our results also showed that, pre-test injection of α1-receptor antagonist prazosin (1, 2 μg/rat) or α2-receptors antagonist yohimbine (1, 2 μg/rat) before effective dose of scopolamine (2 μg/rat) prevented the improvement of memory by pre-test scopolamine. Conclusion: These results suggest that α1- and α2-adrenergic receptors of the dorsal hippocampal CA1 region may play an important role in scopolamine-induced amnesia and scopolamine state-dependent memory

Involvement of dorsal hippocampal α-adrenergic receptors in the effect of scopolamine on memory retrieval in inhibitory avoidance task

The present study evaluated the possible role of α-adrenergic receptors of the dorsal hippocampus on scopolamine-induced amnesia and scopolamine state-dependent memory in adult male Wistar rats. The animals were bilaterally implanted with chronic cannulae in the CA1 regions of the dorsal hippocampus, trained in a step-through type inhibitory avoidance task, and tested 24. h after training to measure step-through latency. Results indicate that post-training or pre-test intra-CA1 administration of scopolamine (1 and 2μg/rat) dose-dependently reduced the step-through latency, showing an amnestic response. Amnesia produced by post-training scopolamine (2μg/rat) was reversed by pre-test administration of the scopolamine that is due to a state-dependent effect. Interestingly, pre-test intra-CA1 microinjection of α1-adrenergic agonist, phenylephrine (1 and 2μg/rat) or α2-adrenergic agonist, clonidine improved post-training scopolamine (2μg/rat)-induced retrieval impairment. Furthermore, pre-test intra-CA1 microinjection of phenylephrine (0.25, 0.5 and 1 μg/rat) or clonidine (0.25, 0.5 and 1 μg/rat) with an ineffective dose of scopolamine (0.25 μg/rat), synergistically improved memory performance impaired by post-training scopolamine. On the other hand, pre-test injection of α1-receptors antagonist prazosin (1 and 2 μg/rat) or α2-receptors antagonist yohimbine (1 and 2 μg/rat) prevented the restoration of memory by pre-test scopolamine. It is important to note that pre-test intra-CA1 administration of the same doses of prazosin or yohimbine, alone did not affect memory retrieval. These results suggest that α1- and α2-adrenergic receptors of the dorsal hippocampal CA1 regions may play an important role in scopolamine-induced amnesia and scopolamine state-dependent memory. © 2010 Elsevier Inc

Association of health and food expenditures inequality with health outcomes: A case study on iranian rural households

Background: Inequality in households' and individuals' consumption expenditures is one of the most important aspects of health status difference among households and individuals. Objectives: We investigated the impact of some macro-economic factors specially inequality factors on the Iranian rural health status since 1986 through 2012. Patients and Methods: We conducted a longitudinal ecological and analytical study. The average sample size was 14602 households whom Iranian Statistics Center selected by a multi-stages clustering sampling approach. All required data has been collected from Iranian Statistics Centre and Deputy for Curial Affaires of Iranian Ministry of Health. We calculated the Gini coefficients for the rural food and health expenditures, then conducted a transloge autoregressive order one (AR1) to investigate the association between the Iranian rural households' key mortality rates and the food and health expenditure Gini coefficients, time trend, GDP per capita (PPP), and GDP per capita Gini coefficients. Results: The mean of Gini coefficients were 0.137 and 0.21 for the rural food expenditures inequality based on current and constant price, respectively. In addition, the mean of Gini coefficients were 0.26 and 0.31 for the rural health expenditures inequality based on current and constant price, respectively. The time trend, transloged form of Gini coefficients for health expenditures and GDP per capita Gini coefficients presented a significant negative correlation with transloged form of neonatal mortality rate. With regard to the transloged form of under five mortality we observed a significant negative correlation with time trend and transloged form of Gini coefficients for health expenditure and GDP per capita. Finally, there was a significant negative correlation between transloged forms of maternal mortality rate. Conclusions: Iranian policy makers should consider the rural health and food expenditures inequality and try to adopt more effective policies and plans to decrease it. In addition, they should improve the macro-economic factors to improve the rural households' health status. © 2014, Iranian Red Crescent Medical Journal

Using quality measures for quality improvement: The perspective of hospital staff

Research objective: This study examines the perspectives of a range of key hospital staff on the use, importance, scientific background, availability of data, feasibility of data collection, cost benefit aspects and availability of professional personnel for measurement of quality indicators among Iranian hospitals. The study aims to facilitate the use of quality indicators to improve quality of care in hospitals. Study design: A cross-sectional study was conducted over the period 2009 to 2010. Staff at Iranian hospitals completed a self-administered questionnaire eliciting their views on organizational, clinical process, and outcome (clinical effectiveness, patient safety and patient centeredness) indicators. Population studied: 93 hospital frontline staff including hospital/nursing managers, medical doctors, nurses, and quality improvement/medical records officers in 48 general and specialized hospitals in Iran. Principal findings: On average, only 69% of respondents reported using quality indicators in practice at their affiliated hospitals. Respondents varied significantly in their reported use of organizational, clinical process and outcome quality indicators. Overall, clinical process and effectiveness indicators were reported to be least used. The reported use of indicators corresponded with their perceived level of importance. Quality indicators were reported to be used among clinical staff significantly more than among managerial staff. In total, 74% of the respondents reported to use obligatory indicators, while this was 68% for voluntary indicators (p<0.05). Conclusions: There is a general awareness of the importance and usability of quality indicators among hospital staff in Iran, but their use is currently mostly directed towards external accountability purposes. To increase the formative use of quality indicators, creation of a common culture and feeling of shared ownership, alongside an increased uptake of clinical process and effectiveness indicators is needed to support internal quality improvement processes at hospital level

The global burden of cancer attributable to risk factors, 2010–19: a systematic analysis for the Global Burden of Disease Study 2019

BACKGROUND: Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. METHODS: The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk–outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. FINDINGS: Globally, in 2019, the risk factors included in this analysis accounted for 4·45 million (95% uncertainty interval 4·01–4·94) deaths and 105 million (95·0–116) DALYs for both sexes combined, representing 44·4% (41·3–48·4) of all cancer deaths and 42·0% (39·1–45·6) of all DALYs. There were 2·88 million (2·60–3·18) risk-attributable cancer deaths in males (50·6% [47·8–54·1] of all male cancer deaths) and 1·58 million (1·36–1·84) risk-attributable cancer deaths in females (36·3% [32·5–41·3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20·4% (12·6–28·4) and DALYs by 16·8% (8·8–25·0), with the greatest percentage increase in metabolic risks (34·7% [27·9–42·8] and 33·3% [25·8–42·0]). INTERPRETATION: The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden

Effect of morphine based CPP on the hippocampal astrocytes of male wistar rats

Opioid abuse is an increasing problem worldwide and the reinforcing effects of opioid analgesics make them susceptible to diversion and illicit use and abuse. As morphological changes in different parts of the brain including the hippocampus and dentate gyrus that have Plasticity is looking for a lot of drug injection in human and animal studies has been viewed. Also other evidences have shown that Astrocytes actively participate in synaptic plasticity. Therefore the aim of this study was obtain of Conditioning Place Preference (CPP) on cell density (Astrocytes number) of rat hippocampal formation. In present study, 48 male Wistar rat weighted average 220-250 g were used. For behavioral tests, rats divided into eight groups and experimental groups daily (three days) received morphine at different doses (2.5, 5, 7.5 mg kg-1) by subcutaneous injection and sham groups, received saline dose (1 mL kg-1) and then CPP test in them were investigated. 48 h after behavioral testing animals were decapitated under chloroform anesthesia and their brains fixed and after tissue processing, slices stained with GFAP immunohistochemistery techniques. Present results showed the most dose responses of morphine were observed in 7.5 mg kg-1. It also revealed that don't exist any differences between the number of astrocytes in CAj and CAg in control group and control-saline, but this difference between control and the other groups was significant statistically (p&lt;0.05). We concluded that the phenomenon of morphine based conditioned place preference can cause a significant increase in the number of astrocytes in experimental groups with compared to controls. © 2011 Academic Journals Inc

Application of a new system for classifying root canal morphology in undergraduate teaching and clinical practice: a national survey in Malaysia

Aim To evaluate and compare the feedback of final year undergraduate dental students in eight Malaysian dental schools on the application of a new system for classifying root canal morphology in teaching and clinical practice. Methods One PowerPoint presentation describing two classification systems for root canal morphology (Oral Surgery Oral Medicine Oral Pathology, 1974 38, 456 and its supplemental configurations, International Endodontic Journal 2017, 50, 761) was delivered to final year undergraduate dental students in eight dental schools in Malaysia by two presenters (each presented to four schools). To examine students' feedback on the utility of each system, printed questionnaires consisting of six questions (five multiple choice questions and one open-ended question) were distributed and collected after the lecture. The questionnaire was designed to compare the classification systems in terms of accuracy, practicability, understanding of root canal morphology and recommendation for use in pre-clinical and clinical courses. The exact test was used for statistical analysis, with the level of significance set at 0.05 (P = 0.05). Results A total of 382 (out of 447) students participated giving a response rate of 86%. More than 90% of students reported that the new system was more accurate and more practical compared with the Vertucci system (P 0.05). The students' responses for all questions were almost similar for both presenters (P > 0.05). Conclusions The new system of International Endodontic Journal 2017, 50, 761 for classifying root and canal morphology was favoured by final year undergraduate dental students in Malaysia. The new system has the potential to be included in the undergraduate endodontic curriculum for teaching courses related to root and canal morphology