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

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

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

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

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

Regional Cerebral Blood Flow in Mood Disorders. II. Comparison of Major Depression and Alzheimer's Disease

We contrasted regional cerebral blood flow in matched groups of 30 patients with major depression,30 patients with Alzheimer's disease and 30 normal controls using the 133Xe inhalation technique. Whereas both the depressed and AIzheimer's disease groups had markedly reduced global cortical blood flow, the Scaled Subproflle Model,developed to identify abnormalities in regional networks, indicated that they had distinct topographic profiles. Previous findings of an abnormal regional network in major depression were unaltered by the inclusion of Alzheimer's disease patients in the analysis. Alzheimer's disease was associated with a distinct parietotemporal deficit and the degree of this abnormality strongly covaried with cognitive impairment. Alzheimer's disease patients also had abnormal manifestation of three other regional networks. We illustrate a method for distinguishing when a disease imposes a new pattern of interactions among brain regions and when a disease alters the expression of regional patterns characteristic of normal functioning