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Given the recent and growing interest in the concepts of prodromal and presymptomatic Alzheimer disease, it is crucial to determine whether the presence of -amyloid (A) in the brain of asymptomatic elderly individuals is a pathologic condition associated with accelerated neuronal and synaptic loss. The aim of the present study was to assess whether A influences the rate of atrophy in cognitively normal elderly individuals.

There is mounting evidence for the contribution of apoE to the pathophysiology of Alzheimer disease (AD). Studies also indicate that plasma apoE levels may reflect disease status, suggesting that apoE is a potential AD biomarker. However, while some studies of apoE levels in plasma have presented correlations with AD pathology, others have not. Thus, there is a lack of consensus as to the suitability of plasma apoE as an AD biomarker. The major objective of this cross-sectional study was to investigate total plasma apoE as well as levels of the apoE4 form in a large, highly characterized cohort which included both healthy controls and participants with early-stage AD.

To investigate whether global and regional -amyloid (A) burden as measured with 11C Pittsburgh compound B (PIB) PET is associated with hippocampal atrophy characterized using MRI in healthy controls and patients with amnestic mild cognitive impairment (aMCI) or Alzheimer disease (AD).

The paper describes an approach to the use of interactive computing to assist students in calculating results from their experimental data in situations where several similar sets of data have to be processed, either by numerical calculation or graphically. The computer programs require the students to show that they understand the calculations by processing one set of data correctly themselves before the remaining sets are computed for them. The detection and diagnosis, by the computer, of students' calculation errors are described. The educational problems and advantages of such an approach are discussed.

Four Hereford × Red Angus yearling steers were acclimated to each of the following environments: cold (3 C), thermoneutrality (TNZ; 20 C) and heat (35 C). Intake was equalized for all treatments at 4.9 · kg · head−1· d−1(2.9 Mcal metabolizable energy/kg). Heat production, respiration rate and rectal temperature were determined after 3- and (21-h later) 24-h exposures to thermoneutral and heat stress test-temperatures: 25. 30, 32.5, 35, 37.5 and 40 C. Thermoneutral heat production (kcal · kg−75· d−1), after 3- and 24-h exposures, was greater (P<.05) for the cold-acclimated cattle (139.6 ± 5.0 and 153.0 ± 5.8) as compared with the TNZ-acclimated cattle (117.7 ± 5.0 and 121.6 ± 5.8). Heat production of the heat-acclimated cattle after 3- and 24-h exposures to thermoneutrality was 121.0 ± 5.1 and 123.5 ± 3.2 and was not different from the TNZ-acclimated cattle. Heat production of steers acclimated to different temperatures was variable during the 3- and 24-h exposures to test-temperatures ranging from 25 to 40 C. Heat production increased linearly in the TNZ-acclimated cattle (24-h exposure) and in the heat-acclimated cattle (3-h exposure) at the rate of 1.3 and 2.3 kcal · kg−75· d−1· C−1increase in test-temperature, respectively. In the other four comparisons, analysis by regression indicated no significant change in heat production. Rectal temperature and respiration rate increased significantly in either a linear or quadratic manner in all treatment groups exposed to test-temperatures from 25 to 40 C. During exposure to environmental temperatures that were high enough to stimulate an increase in respiration rate and rectal temperature, heat production of cattle on equalized intake did not change in a predictable or consistent manner.

When feedlot animals are exposed to thermal stress (hot or cold) average daily gain (ADG) is lowered and gross efficiency of converting nutrients to tissue is reduced. The basis for these observations is increased maintenance energy requirement which reduces energy available for growth. If protein is fed as a constant percentage of the diet then during thermal stress protein content of the diet increases per unit of energy available for growth. Reduced growth rate combined with constant protein intake lowers protein efficiency ratio (PER). It was hypothesized that adjusting protein intake during thermal stress in proportion of expected reduction in ADG would increase PER without further reduction in ADG. In trials with both lambs and cattle fed during both, cold and heat, the hypothesis was substantiated. Therefore, under practical conditions, protein adjustment during thermal stress will improve PER and inturn reduce feed cost per unit gain as a function of the difference between cost of dietary protein and energy.

Metabolism and rumen motility studies were conducted using yearling wethers subjected to three types of noise (at 75 and 100-dB intensities): United States of America Standard Institute (USASI) white noise; instrumental music and intermittent miscellaneous sounds (IMS). Animals ate less (P<.05) when subjected to auditory stimuli that exceeded background noise (48 dB). IMS at 75 and 100 dM increased water intake (P<.05) and metabolizable energy of the ration (P<.01) and improved apparent nutrient digestibilities (P<.03). Nitrogen retention was not affected by sound intensity or type. Level (P<.02), type (P<.05), and their interaction (P<.01) affected urinary creatinine output. After the sheep were exposed to auditory stimuli 15 min, their rumen motility was not altered.

During male puberty, erythropoiesis is exceptionally active. Pubertal development and iron status were followed in 60 healthy boys at 3-month intervals for 24 months to evaluate changes in body iron stores with the serum transferrin receptor–ferritin ratio. The estimated amount of stored iron declined by about 50% over a 2-year period. Remarkable changes in iron stores were found even after as short an interval as 3 months and pubertal development was closely linked with a decrease in stored iron. The annual increments of estimated red blood cell (RBC) iron showed strong positive correlations with velocities in testicular volume and certainly in body height and weight. In contrast, the estimated changes in individual iron stores were not associated with any of those parameters. The lacking associations between iron stores and growth parameters are probably indicative of increasing intestinal absorption. Despite the relatively small quantitative role of iron stores in supplying iron for growth, falling iron stores probably play a more important regulatory role by stimulating iron absorption.

Average daily gain, deviation of actual from predicted gain, daily feed consumption, nitrogen balance, and protein efficiency ratios are given for growing lambs reared at ambient temperatures of —5, 0, 5, 10, 15, 20, 30 and 35 C. Temperature significantly affected average daily gain, deviation of actual from predicted gain, feed consumption, protein efficiency ratio, and nitrogen retention. Altering protein levels during thermal stress is suggested as a means to improve protein efficiency.

Effective temperature is a term used to rate the cooling or heating power of the physical environment in terms of dry bulb temperature. For livestock exposed to cold, windy environments, effective temperature must now be predicted by a wind-chill index prepared for humans and designed without regard to external insulation such as-hair or wool. The human wind-chill relationship is quadratic in nature. When rate of heat loss through animal hides with hair or wool was measured during exposure to temperatures ranging from -23C to 2C and wind velocities from 0 to 56 km per hour a cubic relationship was found. Data presented herein suggest that the human wind-chill index is not valid for animals with natural coverings, particularly at wind velocities greater than 40 km per hour. Instead, the relationship between rate of heat loss and wind velocity for animals with hair or wool is more accurately predicted by the cubic function which may account for the destruction of the external insulation occurring during wind speeds greater than 40 km per hour.

Western blots of normal human platelets, employing a monoclonal antibody raised against the full-length amyloid precursor protein of Alzheimer's disease (APP695), revealed major bands of 100-110 and 120-130 kDa in both cytosolic, membrane, and released fractions. These species were similar in size to forms seen in brain preparations and in plasma. There was no difference in Western blots of platelet preparations from Alzheimer patients compared with controls. Purified platelet amyloid precursor proteins were sequenced and shown to be amino terminally homogeneous. Immunohistochemistry localized the antigen to the platelet and megakaryocyte and demonstrated weak immunostaining of some lymphocytes. Immunoprecipitation of material released from platelets demonstrated that sedimentable full-length APP with the carboxyl-terminal epitope, and soluble APP lacking the carboxyl-terminal epitope, may exist in the circulation. Western blots and carboxyl-terminal and amino-terminal APP radioimmunoassay of material released by platelets in response to stimulation revealed that platelets release APP during degranulation. The function of platelet APP is yet to be determined, but the present studies suggest a role in regulation of the coagulation cascade or in platelet aggregation.

The rate of heat exchange between the skin surface and the external environment depends in part on the existing thermal gradient. Since vasomotor responses affect the flow of heat between the body core and the skin surface, the control of cutaneous blood flow allows modification of the rate of heat exchange. Vasomtor variability which modifies tissue insulation is a thermal regulatory response (Hammel, 1968) and is the only adjustable means of regulating the flow of internal body heat to the skin. The initial response of homeotherms exposed to ambient temperatures above the thermoneutral zone (heat stress) is to increase heat loss by vasodilatation (Hardy, 1961; Adams, 1968; Hammel, 1968). Vasoconstriction at ambient temperatures below the thermoneutral zone (cold stress) minimizes sensible heat loss mainly by increasing tissue insulation.The investigation of biothermal responses of homeotherms to thermal stresses requires the identification of a thermoneutral zone, that is a range of environmental temperature within which the animal need not involve active heat conservation or dissipation.

Early-weaned lambs were subjected to three types of noise: United States of American Standard Institute (USASI) Noise; instrumental music; and intermittent miscellaneous sounds (IMS), at 75 and 100 dB intensities. USASI and IMS at 75 dB intensity increased average daily gain significantly (P<.05), from 0.23 to 0.41 kg and from 0.16 to 0.39 kg, respectively; feed efficiency was also improved. Pooled data from the three trials indicated that both sound type and intensity significantly affected lamb performance. Lambs exposed to music were calm and more docile compared to lambs subjected to USASI and IMS noise. Acclimatization to sound was evident. Neural and neuroendocrine effects are proposed as possible mechanisms of action.

Three hundred thirty observations on 10 Suffolk ewe lambs were used to determine auditory thresholds for sheep. Tests were conducted using a free-field technique in a semi-soundproofed room (background 26 dB). EEG pattern changes and behavioral responses used to determine hearing thresholds correlated highly (r=0.95). Animals tested were most sensitive (lowest threshold) at 7,000 Hz. The resulting audiogram was similar in shape to that for humans but at a higher frequency. Heart and respiratory rates were measured in lambs exposed to different types and levels of noise. Differentiation to both sound type and sound level was apparent, as was acclimation to sound.

Shorn unanesthetized sheep were acutely exposed to ambient temperatures ranging from thermoneutral (25 C) to severe heat stress (45 C). Oxygen consumption, rectal temperature respiration rate and respiratory and cutaneous water loss were measured. Oxygen consumption increased significantly (P<.05) during severe heat stress (45 C). This increase was partitioned into somatic-humoral and Q10portions assuming Q1O=2.O with the Q10effect accounting for as high as 41% of increased metabolic rate during heat stress. Both respiratory and cutaneous water loss are avenues of heat loss in shorn sheep with increased respiratory losses more apparent during mild heat stress (30 and 35 C) and cutaneous water loss more important during severe heat stress (40 and 45 C). Panting indices implied that panting is not a thermal liability in shorn sheep in the range of ambient temperatures studied.

Field trials to test the efficacy of insecticidal semiochemical baits for management of the southern com rootworm, Diabrotica undecimpunctata howardi Barber, in peanuts were conducted in 1992, 1993, and 1994 in North Carolina and Virginia. The baits contained a mixture of cucurbitacins as a feeding arrestant, volatile feeding attractants (1,2,4-trimethoxy-benzene, indole, and trans-cinnamaldehyde), and carbaryl as a toxicant. Results were similar in both North Carolina and Virginia. In 1992 and 1993, there were no statistically significant differences in in-shell yield because of treatment. Numerically highest yields were always obtained in the chlorpyrifos-treated plots; numerically lowest yields occurred in the semiochemical bait-treated plots in 1993 and 1994. In 1994, in-shell yield was significantly higher in the chlorpyrifos-treated than in granular semiochemical bait-treated peanuts. Percentage of undamaged pods was highest in chlorpyrifos-treated and lowest in bait-treated peanuts. Possible reasons for lack of efficacy of baits as applied are discussed relative to the biology of southern corn rootworm in peanuts.

Thirteen researchers from five centers in Australia, Germany, the Netherlands, United Kingdom, and United States applied DSM-III-R and Clinical Dementia Rating (CDR) syndrome-level dementia criteria to written vignettes of 100 elderly people identified in clinics or community surveys. Subjects ranged in type from cognitively intact to severely demented and many were also frail, partially sighted, or deaf. This paper concerns reliability within and between centers, and the relationship between reliability and factors such as diagnostic criteria, dementia severity, and respondents' clinical characteristics. Within-center interrater reliability was high, more so for "yes-no" DSM-III-R diagnoses than the multi-level CDR. Between-center rates were lower but still moderate to good. Concordance was lower for intermediate dementia levels than for no dementia and severe dementia. Physical disability made an additional contribution to uncertainty but deafness, poor vision, anxiety, and depression had no discernible effects. Reliability levels are likely to be lower in representative aged populations than in carefully selected clinical groups.