Assessment of the validity of in vivo methods of measuring human macular pigment optical density.

PURPOSE: As a result of the putative protective role of lutein and zeaxanthin at the site of the retina (macular pigment [MP]), interest in the noninvasive measurement of these retinal carotenoids is increasing. In principle, any method used to measure MP in vivo should provide spectral absorption curves that match extinction spectra of MP measured ex vivo. METHODS: In this article, we assess published spectral curves with respect to this criterion. RESULTS AND DISCUSSION: Variation in derived MP measures resulting from methodological differences between techniques is noted and discussed.     

Dose effects of naloxone on fixed morphine dependence: simultaneous behavioral and 2-deoxyglucose study in the rat

We have simultaneously studied regional cerebral glucose utilization (RCGU) and behavior during naloxone precipitated morphine withdrawal. For RCGU studies, 25 brain regions were analyzed that previously had been shown to participate in morphine withdrawal. Four established behavioral signs of morphine withdrawal were recorded: wet shakes, jumping, weight loss, and autonomic signs. Using a 10(4) range of naloxone dose (0.0005-5.0 mg/kg), dose dependent effects were found for 3 behaviors: jumping, weight loss and autonomic signs. The incidence of wet shakes did not correlate with naloxone dose. Increases in RCGU in several specific brain sites were also naloxone dose dependent. Naloxone dose dependent increases in RCGU during precipitated morphine withdrawal may be divided into 3 classes of responses: Class I structures (paraventricular, ventromedial, and lateral hypothalamus) exhibited their largest RCGU increases between 0.005 and 0.05 mg/kg of naloxone; Class II structures (preoptic areas, basal ganglia, anterior and intralaminar thalamic nuclei, mammillary nuclei, and certain midbrain regions) showed gradual RCGU increases across the 10(4) range of naloxone dose; and, Class III structures (diagonal band, medial and lateral septum, and the central amygdaloid nucleus) displayed large RCGU increases across 0.5-5.0 mg/kg of naloxone. Regression analysis of RCGU vs behavior showed correlations between Class I responses and autonomic signs (P less than 0.010); weight loss was correlated with all 3 classes of naloxone dose dependent RCGU responses during withdrawal (P less than 0.05). The strong positive correlation among these RCGU increases and certain morphine withdrawal behaviors supported the use of RCGU measurements in specific brain sites as a sensitive and objective biochemical indicator of the presence and severity of morphine dependence. In addition, this study demonstrates that changes in RCGU in different brain regions are heterogeneous with respect to naloxone dose and appear reproducibly along a continuum from mild to severe withdrawal.     

Microprocessor-controlled automatic safety testers

Two safety test units were developed using microprocessor technology to identify automatically the equipment under test, to test the safety parameters, and to record the test results. A program written on the IBM/360 computer is used to input, analyze and store these results. The purpose of this program is to provide accurate and reliable test data and better documentation, so that detection and even prediction of safety hazards within the hospital can be accomplished.     

BDNF genetic variants are associated with onset age of familial Parkinson disease: GenePD Study

Brain-derived neurotrophic factor (BDNF) stimulates neuronal growth and protects nigral dopamine neurons in animal models of Parkinson disease (PD). Therefore, BDNF is a candidate gene for PD. The authors investigated five single-nucleotide polymorphisms in 597 cases of familial PD. Homozygosity for the rare allele of the functional BDNF G196A (Val66Met) variant was associated with a 5.3-year older onset age (p = 0.0001). These findings suggest that BDNF may influence PD onset age.     

Resting energy expenditure: a better marker than BMI for BMD in African-American women

PURPOSE: African-American women tend to be more overweight and to have lower resting energy expenditures (REE) compared with Caucasian women. Weight is associated with bone mineral density (BMD), but the relation between BMD and REE has not been reported. METHODS: Four hundred postmenopausal African-American women aged 45-87 (yr) from San Diego, CA participated in this community-based cross-sectional study. Body composition (fat mass, lean body mass), bone mineral content (BMC) and BMD of the lumbar spine, hip (femoral neck, greater trochanter, intertrochanter), and total body were measured using dual energy x-ray absorptiometry (DXA). REE was calculated using the Harris-Benedict equation; grip strength was measured by isometric dynamometry. RESULTS: REE (r range: 0.32-0.79) showed the strongest correlation with spine, total hip, and total body BMC and BMD. In stepwise multiple linear regressions adjusted for age and grip strength, REE explained 15% of the variance in spine BMD, 33% of the variance in total hip, and 32% of the total body BMD variance. REE explained 63% of the total body BMC variance. When body weight replaced REE in the models, weight became the strongest covariate of BMC and BMD but explained 1% less of the variance in spine BMD, 5% less of the variance in total hip BMD, 4% less of the variance in total body BMD, and 3% less of the variances in spine, total hip, and total body BMC than did REE. CONCLUSION: In this cohort of African-American women, weight explained less of the BMC and BMD variance than REE. Poor energy economy may contribute to being overweight and may explain the lower rates of osteoporosis observed in African-American women.