55 research outputs found

    The role of arbuscular mycorrhizal fungi in plant invasion trajectory

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    Background: Invasive plant species pose a global threat because they alter ecosystem functioning and biodiversity. The majority of plants form mutualistic mycorrhizal associations with mycorrhizal fungi, which contribute to the nutrient and water supply as well as diversity, competitive ability, and ecosystem productivity. In addition, the role of mycorrhizal interactions in plant invasiveness and the susceptibility or resistance of a habitat to invasion is increasingly recognized. However, the mechanisms by which mycorrhizae contribute to invasion remain unresolved. Scope Here, we provide an overview of the empirical evidence and discuss the prospects for mycorrhizaemediated plant invasion. Overall, mycorrhizal fungi appear to have impacts on plant invasion that depend on the similarities between the mycorrhizal associations of the alien and native plants. We introduce plant mycorrhizal niche space (PMNS) as a plant’s ability to exploit and shape the mycorrhizal fungi pool of a habitat based on its dependency on mycorrhizal fungi, traits and priority effects. Conclusions Collectively, the available evidence supports the idea that PMNS is independent of place of origin (invasive status). Understanding the drivers of the PMNS of both native and alien plant species may help to predict the potential invasiveness of plants and the invasibility of a habitat, to elucidate the role of the mycorrhizal fungal community in plant invasion and the impact of plant invasion on the structure of the mycorrhizal fungal community in new habitats (i.e., neighbour effect) and to improve restoration planning. In this regard, we highlight a number of knowledge gaps and discuss future research directions

    Validity and reliability of a new food frequency questionnaire compared to 24h recalls and biochemical measurements: Pilot phase of Golestan cohort study of esophageal cancer

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    Background: A pilot study was carried out to evaluate validity and reproducibility of a food frequency questionnaire (FFQ), which was designed to be used in a prospective cohort study in a population at high risk for esophageal cancer in northern Iran. Methods: The FFQ was administered four times to 131 subjects, aged 35-65 years, of both sexes. Twelve 24-h dietary recalls for two consecutive days were administered monthly during 1 year and used as a reference method. The excretion of nitrogen was measured on four 24-h urine samples, and plasma levels of β-carotene, retinol, vitamin C and α-tocopherol was measured from two time points. Relative validity of FFQ and 24-h diet recall was assessed by comparing nutrient intake derived from both methods with the urinary nitrogen and plasma levels of β-carotene, retinol, vitamin C and α-tocopherol. Results: Correlation coefficients comparing energy and nutrients intake based on the mean of the four FFQ and the mean of twelve 24-h diet recalls were 0.75 for total energy, 0.75 for carbohydrates, 0.76 for proteins and 0.65 for fat. Correlation coefficients between the FFQ-based intake and serum levels of β-carotene, retinol, vitamin C and vitamin E/α-tocopherol were 0.37, 0.32, 0.35 and 0.06, respectively. Correlation coefficients between urinary nitrogen and FFQ-based protein intake ranged from 0.23 to 0.35. Intraclass correlation coefficients used to measure reproducibility of FFQ ranged from 0.66 to 0.89. Conclusion: We found that the FFQ provides valid and reliable measurements of habitual intake for energy and most of the nutrients studied. © 2006 Nature Publishing Group. All rights reserved

    "Growth Chart Study in Children Under 5 Years Old in Rural Area of Khoramabad Province"

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    Growth chart is the best measure for weight monitoring of children. Most factors that affect child heath show their effect on child weight. This cross sectional and descriptive analytical study was achieved to estimate malnutrition prevalence and effective factors in children under 5 years old in rural area of Khoramabad province. 555 girls and 570 boys were chosen from health houses by cluster sampling. Data were gathered through questionnaires. verbal interviews and child weighing. Nutritional status was estimated via weight/age index and the data were analysed by chi-square test. The results show 7.7% malnutrition among the children in this area. Factors that influence the nutritional status were: Frequency of diarrhea and acute respiratory infection, birth weight, duration of breast feeding and milk formula

    Comparative survey of smoking prevalence in individuals with and without angular bone defects

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    "nBackground and Aims: There is not sufficient knowledge about the relationship between smoking and vertical bone loss in periodontal diseases. There are also important evidences which propose harmful effects of smoking on periodontal tissues including alveolar bone. The purpose of this study was to assess the relationship between smoking and prevalence and severity of vertical bone defects."nMaterials and Methods: This case-control study consisted of 71 individuals with angular bone defects (case) and 69 individuals without angular bone defects (control) between 18 to 70 years old. People were selected by radiography, examining and filling up the questionnaire. Vertical bone defect was defined as interproximal bone resorption to the extent of ≥2mm with a clear angel towards the Mesial or Distal of root. Data were analyzed using SPSS software."nResult: The mean age of studied individuals was 37.14 years (±12.72). Among people with angular bone defects, 21.1% were light smokers and 25.4% were moderate-heavy smokers. There was a significant difference between smokers and nonsmokers in terms of smoking status and the chance of having angular bone defects (P=0.001). Simultaneous study of the effect of sex, age, brushing and smoking status showed that except sex, other variables have a significant effect on angular bone defects. The chance of having angular bone defects in light and heavy-moderate smokers was more than that in nonsmokers (adjusted OR=4.17 and adjusted OR=3.87, respectively)."nConclusion: These observations propose that smoking is related to increase in prevalence and severity of vertical bone defects. Smoking is considered as a potential risk factor for vertical periodontal bone loss

    Evaluation of Inheritance Pattern in Mentally Retarded Children

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    Introduction: Mental retardation is one of the most important problems of general health. The purpose of this study was to evaluate inheritance pattern of mentally retarded patients in Yazd city. Methods: In a descriptive cross- sectional study, all medical records and pedigrees of 320 mentally retarded children whose parents had referred for genetic consultation to the Welfare center of Yazd city were reviewed. Results: Of the total, 62.8% of the parents had consanguineous marriage. Mean inbreeding coefficient of offsprings was 0.0713 in third degree related parents versus 0.0156 in non-related parents. Mental retardation was seen in 43.4% of first– degree relatives of children (6.6% of parents and 36.8% of siblings, respectively). Frequency of mental retardation did not differ significantly in both sexes. Pedigree showed inheritance pattern in 43.4% of patients (autosomal recessive, autosomal dominant and x-linked inheritance pattern were seen in 33.75%, 6.9% and 2.8%, respectively), while 37% of patients had no definite inheritance pattern. Abnormal karyotype were seen in 19.4% of patients, 28 of whom(8.75% of all patients) had Down syndrome. The prevalence of autosomal recessive inheritance in patients with consanguineous marriages and non family marriages was 62.8 % and 10%, respectively (P=0. 002). Conclusion: Since multiple cases of mental retardation were seen in families and rate of consanguineous marriage was more in parents of mentally retarded children, genetic counseling in consanguinity marriages and families of mentally retarded children can prevent incidence of mental retardation in these families

    Prevalence and Associated Factors of Insomnia Syndrome in the Elderly Residing in Kahrizak Nursing Home, Tehran, Iran

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    Background: As insomnia is common, especially among the elderly in the nursing homes, we aimed to estimate insomnia prevalence among the elderly residing in nursing homes as well as to determine factors associated with insomnia in the elderly.Methods: This cross-sectional study was carried out in 2009 on 772 elderly residents at Kahrizak Nursing Home, Tehran Iran. The information was gathered through 5-part questionnaires by interviewing either the individuals or the nurses in charge and also reviewing the subjects' medical files. Eventually, the necessary data were analyzed using one-way ANOVA and Chi-square tests.Results: The mean age of the participants was 76.8 ± 8.05 years (range, 65 to 107 years). Based on the results, 303 (39.2%) of the elderly, including 86 (34.7%) men and 217 (41.1%) women, had insomnia syndrome. 433 (56.1%) participants complained of difficulty initiating sleep, 357 (46.2%) of disrupted sleep, 362 (46.9%) of early morning awakening, and 313 (40.5%) of non-restorative sleep. Our findings also showed that age (P = .004), number of diseases (P = .019), motility status (P = .017), sleep environment satisfaction (P < .001), cognitive status (P = .023), and functional autonomy (P = .003) were significantly associated with insomnia.Conclusion: Insomnia is a prevalent disorder amongst the nursing home elderly population, especially elderly women, and several pharmaceutical and nonpharmaceutical factors may trigger its occurrence. However, to prevent this problem, further studies are required in Iran and Middle Eastern region to establish a reliable understanding about insomnia patterns, causes, and cures

    "Beneficial effects of vitamin C and vitamin E on blood pressure in Hyperandrogenic women "

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    Hyperandrogenism affects 2-6% of all women. Hypertension is one of disturbances which is related to androgen excess. Higher intakes of vitamin C and vitamin E have been associated with lower blood pressure. Tho investigate the effect of these vitamin supplementation on blood pressure in hyperandrogenic women, a randomized, double-blind, placebo-controlled study was designed on 56 women 18-54 years old. Women were randomly allocated to one of four treatment groups: spironolactone plus vitamain C and viamin E (SCE), spironolactone plus vitamins placebo (SP), vitamin C plus vitamin E (CE), vitamins placebo (P). The treatment consisted of oral administration of 100 mg spironolactone, 1000 mg vitamin C and 900 mg vitamin E (alpha-tocopherol acetate) daily for about 3 months. Results indicated that compared to pretreatment, vitamins supplementation significantly lowered systolic (119.1±12.6 vs. 112.6±15.4 mmHg) and mean blood pressure (97.4±11.5 vs. 92. ±12.1 mmHg) SCE group (P&lt;0.05), diastolic (87.3±12.7 vs. 80±12 mmHg) and mean group (P&lt;0.05). Blood levels of vitamin C and alpha-tocopherol increased in all SCE and CE subjects. In conclusion, vitamin C and vitamin E supplementation reduced blood pressure in hperandrogenic women who are at risk of hypertension
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