How to Block Cartel Formation and Price-Fixing

Abstract written by the AEI-Brookings Joint Center: Allowing foreign buyers of goods produced by international cartels to pursue civil antitrust damages in U.S. courts would better deter cartel formation and price-fixing than do sanctions currently imposed by global criminal and civil justice systems.Technology and Industry, Regulatory Reform, Other Topics

APOE Related Alterations in Cerebral Activation Even at College Age

BACKGROUND: Associations between the APOE genotype and various medical conditions have been documented at a very young age. The association between the APOE genotype and cognitive performance varies at different ages. APOE related changes in brain activation have been recently reported for middle aged and elderly subjects. OBJECTIVE: To explore APOE related alterations during cognitive activation in a population of young adults. METHODS: Using H2(15)O positron emission tomography (PET), imaging was carried out in 20 healthy young adults (age 19 to 28 years; four epsilon4 carriers and 16 non-epsilon4 carriers) during a non-verbal memory task. Voxel-wise multiple regression analyses were undertaken, with the activation difference PET counts as the dependent variable and the APOE genotype as the independent variable. RESULTS: Brain regions were identified where epsilon4 carriers showed significantly lower or higher activation than non-carriers. CONCLUSIONS: The results suggest that APOE dependent modulation of cerebral flow may be present even at a young age. This may reflect an APOE related physiological heterogeneity which may or may not predispose to brain disease in the ensuing decades or, less likely, the effect of very early Alzheimer's disease related pathological changes

APOE-Dependent Pet Patterns of Brain Activation in Alzheimer Disease

Using H215O PET, the authors imaged 13 patients with Alzheimer disease (AD) while performing a serial nonverbal recognition memory task. Patterns of brain activation differed as a function of APOE genotype: {epsilon}4 carriers exhibited lower activation in the left lingual gyrus and higher activation in left cuneus, precuneus, parahippocampal, and right precentral gyrus. The APOE genotype seems to play a role in cerebral physiologic activity even after onset of clinical manifestations of AD

Cognitive Reserve Modulates Functional Brain Responses During Memory Tasks: A Pet Study in Healthy Young and Elderly Subjects

Cognitive reserve (CR) is the ability of an individual to cope with advancing brain pathology so that he remains free of symptomatology. Epidemiological evidence and in vivo neurometabolic data suggest that CR may be mediated through education or IQ. The goal of this study was to investigate CR-mediated differential brain activation in 17 healthy young adults and 19 healthy elders. Using nonquantitative H(2)(15)O PET scanning, we assessed relative regional cerebral blood flow while subjects performed a serial recognition memory task under two conditions: nonmemory control (NMC), in which one shape was presented in each study trial; and titrated demand (TD), in which study list length was adjusted so that each subject recognized shapes at approximately 75% accuracy. A factor score that summarized years of education and scores on two IQ indices was used as an index of CR. Voxel-wise, multiple regression analyses were performed with TD minus NMC difference PET counts as the dependent variable and the CR variable as the independent variable of interest. We identified brain regions where regression slopes were different from zero in each separate group, and also those where regression slopes differed between the two age groups. The slopes were significantly more positive in the young in the right inferior temporal gyrus, right postcentral gyrus, and cingulate, while the elderly had a significantly more positive slope in left cuneus. Brain regions where systematic relationships between CR and brain activation differ as a function of aging are loci where compensation for aging has occurred. They may mediate differential ability to cope with brain changes in aging

Use of mycophenolate mofetil in steroid-dependent and -resistant nephrotic syndrome

Cyclosporin (Cs-A) is an effective treatment for difficult cases of nephrotic syndrome (NS), but its use can be complicated by renal toxicity and a high incidence of relapses after withdrawal. We reviewed the charts of 10 Cs-A-dependent patients and 4 patients with steroid-dependent nephrotic syndrome (SDNS) not previously treated with Cs-A therapy. All patients had persistent NS, even after prior treatment with oral cyclophosphamide. Of 10 patients treated with Cs-A, 4 had surveillance renal biopsies consistent with Cs-A toxicity, and 8 of 10 had interstitial fibrosis prior to mycophenolate mofetil (MMF). Patients were treated with MMF, at 1,200 mg/m 2 per day, in an attempt to allow weaning of Cs-A and/or steroid therapy, and reduce the frequency of relapses. Overall, a significant decrease in frequency of relapses was noted after initiation of MMF therapy. In addition, 5 patients were weaned off Cs-A by 1–2 years of follow-up. One patient was weaned off Cs-A and MMF, and remained in complete remission. However, the subgroup of patients with frequently relapsing SDNS not treated with Cs-A appeared to have a reduction in the number of relapses while on MMF that did not reach statistical significance. Two patients with intractable steroid-resistant NS continued to relapse repeatedly on MMF and Cs-A therapy. We conclude that in this small, single-center, uncontrolled experience, MMF therapy in patients with Cs-A-dependent NS appears to be effective in reducing Cs-A exposure. In addition, MMF appears to significantly decrease the frequency of relapses in this patient population. Further controlled studies are warranted to better define the potential efficacy and side effects of long-term MMF therapy in this setting.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47822/1/467_2003_Article_1175.pd

Brain Networks Associated with Cognitive Reserve in Healthy Young and Old Adults

In order to understand the brain networks that mediate cognitive reserve, we explored the relationship between subjects' network expression during the performance of a memory test and an index of cognitive reserve. Using H215O positron emission tomography, we imaged 17 healthy older subjects and 20 young adults while they performed a serial recognition memory task for nonsense shapes under two conditions: low demand, with a unique shape presented in each study trial; and titrated demand, with a study list size adjusted so that each subject recognized shapes at 75% accuracy. A factor score that summarized years of education, and scores on the NART and the WAIS-R Vocabulary subtest was used as an index of cognitive reserve. The scaled subprofile model was used to identify a set of functionally connected regions (or topography) that changed in expression across the two task conditions and was differentially expressed by the young and elderly subjects. The regions most active in this topography consisted of right hippocampus, posterior insula, thalamus, and right and left operculum; we found concomitant deactivation in right lingual gyrus, inferior parietal lobe and association cortex, left posterior cingulate, and right and left calcarine cortex. Young subjects with higher cognitive reserve showed increased expression of the topography across the two task conditions. Because this topography, which is responsive to increased task demands, was differentially expressed as a function of reserve level, it may represent a neural manifestation of innate or acquired reserve. In contrast, older subjects with higher cognitive reserve showed decreased expression of the topography across tasks. This suggests some functional reorganization of the network used by the young subjects. Thus, for the old subjects this topography may represent an altered, compensatory network that is used to maintain function in the face of age-related physiological changes

Impairment of Nonverbal Recognition in Alzheimer Disease: A Pet O-15 Study

OBJECTIVE: To characterize deficits in nonverbal recognition memory and functional brain changes associated with these deficits in Alzheimer disease (AD). METHODS: Using O-15 PET, we studied 11 patients with AD and 17 cognitively intact elders during the combined encoding and retrieval periods of a nonverbal recognition task. Both task conditions involved recognition of line drawings of abstract shapes. In both conditions, subjects were first presented a list of shapes as study items, and then a list as test items, containing items from the study list and foils. In the titrated demand condition, the shape study list size (SLS) was adjusted prior to imaging so that each subject performed at approximately 75% recognition accuracy; difficulty during PET scanning in this condition was approximately matched across subjects. A control task was used in which SLS = 1 shape. RESULTS: During performance of the titrated demand condition, SLS averaged 4.55 (+/-1.86) shapes for patients with AD and 7.53 (+/-4.81) for healthy elderly subjects (p = 0.031). However, both groups of subjects were closely matched on performance in the titrated demand condition during PET scanning with 72.17% (+/-7.98%) correct for patients with AD and 72.25% (+/-7.03%) for elders (p = 0.979). PET results demonstrated that patients with AD showed greater mean differences between the titrated demand condition and control in areas including the left fusiform and inferior frontal regions (Brodmann areas 19 and 45). CONCLUSIONS: Relative fusiform and inferior frontal differences may reflect the Alzheimer disease (AD) patients' compensatory engagement of alternate brain regions. The strategy used by patients with AD is likely to be a general mechanism of compensation, rather than task-specific

A calculation of the BBB_{B} parameter in the static limit

We calculate the $B_{B}$ parameter, relevant for $\overline{B}^0$ -- $B^0$ mixing, from a lattice gauge theory simulation at $\beta = 6.0$. The bottom quarks are simulated in the static theory, the light quarks with Wilson fermions. Improved smearing functions produced by a variational technique, MOST, are used to reduce statistical errors and minimize excited-state contamination of the ground-state signal. We obtain $B_B(4.33 GeV) = 0.98^{+4}_{-4}$ (statistical) $^{+3}_{-18}$ (systematic) which corresponds to $\widehat{B}_B = 1.40^{+6}_{-6}$ (statistical) $^{+4}_{-26}$ (systematic) for the one-loop renormalization-scheme-independent parameter. The systematic errors include the uncertainty due to alternative (less favored) treatments of the perturbatively-calculated mixing coefficients; this uncertainty is at least as large as residual differences between Wilson-static and clover-static results. Our result agrees with extrapolations of results from relativistic (Wilson) heavy quark simulations.Comment: 39 pages (REVTeX) including 10 figures (PostScript); Final version accepted for publication: Added new section for clarity; Included comparison to recent results by other groups; slight numerical changes; Essential conclusions remain the sam