1,383 research outputs found
A Modified Forage System for Stocker Production in the Southern Great Plains, USA
Putting low-cost gain on yearling cattle with forages is an important agricultural activity in the Southern Great Plains. The primary forage system within the area incorporates two forages: winter wheat (Triticum aestivum) for grazing in fall through spring, and warm- season grasses in the summer (Fig. 1). These systems have significant gaps in time when high-quality forage is not available. This study tested the function of introduced cool-season perennial grasses in filling the spring gap, and their capacity as large-scale replacements for winter wheat
Graze-Out Plus: Filling Forage Gaps in the Southern Great Plains, USA
Putting low-cost gain on yearling cattle with forages is a significant agricultural activity in the Southern Great Plains. The primary forage system within the area has two components: winter wheat (Triticum aesitivum) grazed from fall through spring (Redmon et al., 1995), and warm-season perennial grasses for summer grazing. This system has significant gaps (Fig. 1) when high-quality forage is not readily available (September-November and May-June). Introduced cool-season perennial grasses have longer growing seasons than wheat, and could help fill these gaps. This experiment tested the function of an introduced cool-season perennial grass, new to the southern Great Plains, in a stocker production system involving intensive grazing of paddocks
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Mediterranean Diet and Alzheimer Disease Mortality
BACKGROUND: We previously reported that the Mediterranean diet (MeDi) is related to lower risk for Alzheimer disease (AD). Whether MeDi is associated with subsequent AD course and outcomes has not been investigated. OBJECTIVES: To examine the association between MeDi and mortality in patients with AD. METHODS: A total of 192 community-based individuals in New York who were diagnosed with AD were prospectively followed every 1.5 years. Adherence to the MeDi (0- to 9-point scale with higher scores indicating higher adherence) was the main predictor of mortality in Cox models that were adjusted for period of recruitment, age, gender, ethnicity, education, APOE genotype, caloric intake, smoking, and body mass index. RESULTS: Eighty-five patients with AD (44%) died during the course of 4.4 (+/-3.6, 0.2 to 13.6) years of follow-up. In unadjusted models, higher adherence to MeDi was associated with lower mortality risk (for each additional MeDi point hazard ratio 0.79; 95% CI 0.69 to 0.91; p = 0.001). This result remained significant after controlling for all covariates (0.76; 0.65 to 0.89; p = 0.001). In adjusted models, as compared with AD patients at the lowest MeDi adherence tertile, those at the middle tertile had lower mortality risk (0.65; 0.38 to 1.09; 1.33 years' longer survival), whereas subjects at the highest tertile had an even lower risk (0.27; 0.10 to 0.69; 3.91 years' longer survival; p for trend = 0.003). CONCLUSION: Adherence to the Mediterranean diet (MeDi) may affect not only risk for Alzheimer disease (AD) but also subsequent disease course: Higher adherence to the MeDi is associated with lower mortality in AD. The gradual reduction in mortality risk for higher MeDi adherence tertiles suggests a possible dose-response effect
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Selective Decline in Memory Function among Healthy Elderly
Objective: To use longitudinally acquired data to establish whether aging is associated with memory decline. Background: Memory loss is one of the most frequent complaints among the elderly. Nevertheless, age-related memory decline remains controversial in large part because it has been established with cross-sectional studies. Methods: A total of 212 community-based healthy people were followed prospectively and evaluated annually with a neuropsychological battery testing memory and other cognitive domains. To control for the learning effect—the improvement in test performance associated with repeated exposure—longitudinal performance was compared between two age groups. Results: The older age group displayed a relative decline in memory performance with time. In contrast to memory, a relative age-related decline was not observed in tests of language, visuospatial ability, and abstract reasoning. Furthermore, within the memory domain, age-related decline was restricted to a specific aspect of memory, manifesting only in a measure sensitive to the acquisition and early retrieval of new information, and not in a measure of memory retention. This profile of age-related cognitive decline anatomically localizes to the hippocampal formation. Conclusion: This study establishes age-related memory decline using longitudinal data, and shows that this decline does not occur diffusely across multiple cognitive domains. Both early AD as well as non-AD processes likely contribute to age-related memory decline, and continued follow-up may reveal distinguishing features between these two
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Gray-Matter Degeneration in Presenile Alzheimer's Disease
Previous comparisons between presenile Alzheimer's disease (AD) and senile dementia of the Alzheimer type (SDAT) did not control for disease severity and duration. In the current study, 18 patients with each diagnosis were matched for disease duration, cognitive dysfunction, and behavioral symptoms (using the modified Mini-Mental Status [mMMS] examination and the Blessed Dementia Rating Scale [BDRS]). Regional cerebral blood flow (rCBF) was quantified by the 133xenon inhalation technique, and several indices of tissue perfusion were examined. The two variables of primary interest were relative gray-matter weight and a gray-matter perfusion index, the initial slope index. Presenile onset was associated with loss of gray-matter relative weight (35% in presenile patients versus 39% in senile patients and healthy control subjects, p = 0.006), with neither perfusion nor disease severity differences between the two dementia samples. This loss of gray matter was significantly related to both severity and duration of disease in the patients with presenile AD, but not in patients with SDAT. These findings lend support to previous suggestions of greater degenerative process in presenile AD and confirm the need to examine and control age of onset in future investigations of AD. Further, correlation analysis suggests greater proportion of common variance among clinical and physiological indices in presenile AD
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Mediterranean Diet and Risk for Alzheimer's Disease
OBJECTIVE: Previous research in Alzheimer's disease (AD) has focused on individual dietary components. There is converging evidence that composite dietary patterns such as the Mediterranean diet (MeDi) is related to lower risk for cardiovascular disease, several forms of cancer, and overall mortality. We sought to investigate the association between MeDi and risk for AD. METHODS: A total of 2,258 community-based nondemented individuals in New York were prospectively evaluated every 1.5 years. Adherence to the MeDi (zero- to nine-point scale with higher scores indicating higher adherence) was the main predictor in models that were adjusted for cohort, age, sex, ethnicity, education, apolipoprotein E genotype, caloric intake, smoking, medical comorbidity index, and body mass index. RESULTS: There were 262 incident AD cases during the course of 4 (+/-3.0; range, 0.2-13.9) years of follow-up. Higher adherence to the MeDi was associated with lower risk for AD (hazard ratio, 0.91; 95% confidence interval, 0.83-0.98; p = 0.015). Compared with subjects in the lowest MeDi tertile, subjects in the middle MeDi tertile had a hazard ratio of 0.85 (95% confidence interval, 0.63-1.16) and those at the highest tertile had a hazard ratio of 0.60 (95% confidence interval, 0.42-0.87) for AD (p for trend = 0.007). INTERPRETATION: We conclude that higher adherence to the MeDi is associated with a reduction in risk for AD. Ann Neurol 2006
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Primary Care Expenditures before the Onset of Alzheimer's Disease
Objective: To investigate primary care expenditures in the period before diagnosis of AD. Methods: In a population-based sample of Medicare enrollees in New York City, person-level 1996 Medicare claims, summed over primary care encounters, were examined for people who developed AD in 1997 to 1998 and those who did not. Results: People who developed AD were more likely to use Medicare outpatient and ambulatory care 1 to 2 years before diagnosis. Compared with respondents who did not develop AD, the excess cost for men was 239 (26% higher). Among elderly people ≥75 years in the United States, the prodromal period of AD was associated with an excess Medicare-based primary care cost of 194.7 million. Conclusion: In addition to huge costs associated with AD after diagnosis, prediagnosis costs are an unrecognized source of expenditures related to the disease
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Differential Regional Dysfunction of the Hippocampal Formation among Elderly with Memory Decline and Alzheimer's Disease
The hippocampal formation is composed of separate anatomical regions interconnected to form a circuit, and investigating abnormal hippocampal function is most revealing at the level of these regions. Until recently, regional analysis of the hippocampal formation could be performed only in animals or in human postmortem tissue. Here, we report a method using functional magnetic resonance imaging that evaluates the hippocampal regions in vivo, and we use this method to study elderly with normal memory, with isolated memory decline, and with probable Alzheimer's disease (AD). Although age-related memory decline occurs commonly, the cause of this decline remains unknown, with disagreement as to whether this decline represents one or more etiologies. Analysis revealed two distinct patterns of regional dysfunction among elderly with isolated memory decline--one pattern similar to that found in elders with AD, involving all hippocampal regions, and a second pattern with dysfunction restricted to only one hippocampal region, the subiculum. These results offer direct evidence of hippocampal dysfunction associated with memory decline in the elderly, and implicate both predementia AD and non-AD processes as possible underlying cause
Mediterranean Diet and Mild Cognitive Impairment
Background: Higher adherence to the Mediterranean diet (MeDi) may protect from Alzheimer disease (AD), but its association with mild cognitive impairment (MCI) has not been explored. Objective: To investigate the association between the MeDi and MCI. Design, Setting, and Patients: In a multiethnic community study in New York, we used Cox proportional hazards to investigate the association between adherence to the MeDi (0-9 scale; higher scores indicate higher adherence) and (1) the incidence of MCI and (2) the progression from MCI to AD. All of the models were adjusted for cohort, age, sex, ethnicity, education, APOE genotype, caloric intake, body mass index, and duration between baseline dietary assessment and baseline diagnosis. Main Outcome Measures: Incidence of MCI and progression from MCI to AD. Results: There were 1393 cognitively normal participants, 275 of whom developed MCI during a mean (SD) follow-up of 4.5 (2.7) years (range, 0.9-16.4 years). Compared with subjects in the lowest MeDi adherence tertile, subjects in the middle tertile had 17% less risk (hazard ratio [HR] = 0.83; 95% confidence interval [CI], 0.62-1.12; P = .24) of developing MCI and those in the highest tertile had 28% less risk (HR = 0.72; 95% CI, 0.52-1.00; P = .05) of developing MCI (trend HR = 0.85; 95% CI, 0.72-1.00; P for trend = .05). There were 482 subjects with MCI, 106 of whom developed AD during a mean (SD) follow-up of 4.3 (2.7) years (range, 1.0-13.8 years). Compared with subjects in the lowest MeDi adherence tertile, subjects in the middle tertile had 45% less risk (HR = 0.55; 95% CI, 0.34-0.90; P = .01) of developing AD and those in the highest tertile had 48% less risk (HR = 0.52; 95% CI, 0.30-0.91; P = .02) of developing AD (trend HR = 0.71; 95% CI, 0.53-0.95; P for trend = .02). Conclusions: Higher adherence to the MeDi is associated with a trend for reduced risk of developing MCI and with reduced risk of MCI conversion to AD
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