Changes of respiratory chain activity in mitochondrial and synaptosomal fractions isolated from the gerbil brain after graded ischaemia

In this study we have examined (1) the integrated function of the mitochondrial respiratory chain by polarographic measurements and (2) the activities of the respiratory chain complexes I, II-III, and IV as well as the ATP synthase (complex V) in free mitochondria and synaptosomes isolated from gerbil brain, after a 30-min period of graded cerebral ischaemia. These data have been correlated with cerebral blood flow (CBF) values as measured by the hydrogen clearance technique. Integrated functioning of the mitochondrial respiratory chain, using both NAD-linked and FAD-linked substrates, was initially affected at CBF values of approximately 35 ml 100 g-1 min-1, and declined further as the CBF was reduced. The individual mitochondrial respiratory chain complexes, however, showed differences in sensitivity to graded cerebral ischaemia. Complex I activities decreased sharply at blood flows below approximately 30 ml 100 g-1 min-1 (mitochondria and synaptosomes) and complex II-III activities decreased at blood flows below 20 ml 100 g-1 min-1 (mitochondria) and 35-30 ml 100 g-1 min-1 (synaptosomes). Activities declined further as CBF was reduced below these levels. Complex V activity was significantly affected only when the blood flow was reduced below 15-10 ml 100 g-1 min-1 (mitochondria and synaptosomes). In contrast, complex IV activity was unaffected by graded cerebral ischaemia, even at very low CBF levels.     

Age-related slowing and the time course of semantic priming in visual word identification.

Investigated, in 4 experiments, the time course of semantic priming effects during 2 forms of visual word identification, lexical decision and pronunciation. On each trial, a target letter string was preceded by a single-word priming context. The effects of varying the stimulus onset asynchrony between the prime and the target indicated that the time course of semantic priming was equivalent for young and older adults. There were no consistent differences between lexical decision and pronunciation in the time course of semantic priming. The age differences associated with response selection were greater than would be predicted by generalized age-related slowing. The semantic priming effects were also inconsistent with a generalized slowing model, but the reliability of these effects was substantially lower than the reliability of the other task-related variables. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Depressed mood does not explain neuropsychological deficits in HIV-infected persons.

The relationship of depressed mood to cognitive disturbance in HIV infection was examined in a sample of 139 homosexual men. Ss were grouped according to the classification of the Centers for Disease Control: 39 were in Group IV, 62 were in Group II or Group III, and 38 were HIV-negative. Ss completed the Profile of Mood States and 10 neuropsychological tests. Analysis employing a classification approach indicated that, although symptoms of depression and neuropsychological impairment were more common in Ss who were HIV-positive, particularly those classified as Group IV, there were no systematic relationships between depression and neuropsychological impairment. Depressed mood and cognitive disturbance each seem to have unique associations to HIV illness status. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dispersion characterization in layered double hydroxide/Nylon 66 nanocomposites using FIB imaging

Layered double hydroxides (LDHs), a newly emerging 2D host material, consist of cationic brucite-like layers and exchangeable interlayer anions. In this work, the morphology and dispersion of LDH particles in LDH/Nylon 66 (salt) nanocomposites has been investigated using focused ion beam (FIB) techniques, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The FIB images show that LDHs are present in the polymer phase dispersed to different degrees, with partial intercalation, exfoliation, and aggregation all being observed. The most even dispersion was achieved in nanocomposites with the lowest loading (0.5 wt % LDH). Residual tactoids and agglomerates were most common in the samples made with the highest concentration of LDHs studied here (5 wt %). The dispersion observed using FIB was consistent with TEM and XRD analysis, yet this technique had significant benefits in terms of time and simplicity over these “conventional” technologies. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

On the Locus of Speed-Accuracy Trade-Off in Reaction Time: Inferences From the Lateralized Readiness Potential.

Lateralized readiness potentials (LRPs) were used to determine the stage(s) of reaction time (RT) responsible for speed-accuracy trade-offs (SATs). Speeded decisions based on several types of information were examined in 3 experiments, involving, respectively, a line discrimination task, lexical decisions, and an Erikson flanker task. Three levels of SAT were obtained in each experiment by adjusting response deadlines with an adaptive tracking algorithm. Speed stress affected the duration of RT stages both before and after the start of the LRP in all experiments. The latter effect cannot be explained by guessing strategies, by variations in response force, or as an indirect consequence of the pre-LRP effect. Contrary to most models, it suggests that SAT can occur at a late postdecisional stage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The MUC2 gene product: a human intestinal mucin

Sera from 82 cases of leptospirosis (confirmed by micro-agglutination tests or IFAT) and 108 patients with other diseases were investigated using the microcapsule agglutination test (MCAT) for leptospirosis. The overall sensitivity (90.2%), specificity (96.3%), positive predictive value (94.9%), negative predictive value (92.9%), and accuracy of the MCAT (93.7%) were encouraging. MCAT is simple, can be performed by unskilled personnel with minimum laboratory facilities, and produces results in 3 h. MCAT would be a reliable serodiagnostic test for rapidly screening individuals for leptospirosis, in various geographical areas of Thailand.     

Integrating mental health services within primary care. A Canadian program

The increasingly prominent role of the family physician in delivering mental health care can be enhanced if productive and collaborative relationships can be established with local mental health services. This paper describes a Canadian program that has achieved this by bringing mental health counselors and psychiatrists into the offices of 87 family physicians in 35 practices in a community in Southern Ontario. The paper describes the program, the activities of counselors and psychiatrists within the practices, and the administrative structures set up to coordinate these activities. Data is presented from the evaluation of the first year of the program's operation (13 practices and 45 family physicians) during which time 3085 referrals were received. The program made mental health care more available and accessible, increased continuity of care, provided additional support for the family physician, offered new opportunities for continuing education, and led to a reduced and more efficient use of other mental health services. The components of the program can be adapted to most communities.     

Effect of atherogenic diet on chicken plasma lipids and lipoproteins

Adult male White Leghorn chickens were used in an experimental model system to study atherogenesis, and the effects of an atherogenic diet on plasma lipoprotein composition including carotenoids were determined. This model also included treatment with diazepam, a drug known to reduce formation of atherogenic plaques. After 6 wk consumption of a high-cholesterol, high-triglyceride diet, chickens had mean total plasma cholesterol, triglyceride, and carotenoid concentrations that were significantly increased over those from chicks that consumed the standard diet. Diazepam treatment had no significant effect on whole plasma concentrations of these lipids. Total body weight gain was unaffected by diet, but liver weight expressed as percentage of body weight was significantly increased in chickens that consumed the atherogenic diet. High density lipoprotein (HDL) and low density lipoprotein (LDL) fractions were isolated from plasma samples by ultracentrifugation. The atherogenic diet increased the carotenoid, cholesterol, and protein content of the LDL fractions but not the HDL fractions.     

Policy Analysis, Peer Reviewed: Evaluation of Bioaccumulation Factors in Regulating Metals

Regulations.