Shawn M Marks

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Researchers employing Pittsburgh Compound B positron emission tomography (PIB-PET) imaging have consistently indentified old normal control (oNC) subjects with elevated tracer uptake, suggesting the presence of beta-amyloid deposition in these individuals. However, a consensus regarding the level at which PIB reveals a biologically meaningful signal does(More)
The purposes of this study were to characterize the subjective, psychomotor and physiological effects of nalbuphine in healthy non-drug abusing volunteers and to compare and contrast the effects of equianalgesic doses of nalbuphine and morphine. Subjects (12 males, 4 females) without histories of opiate dependence were injected in an upper extremity vein(More)
PURPOSE To review current literature with respect to the diagnosis and assessment of velopharyngeal inadequacy (VPI), including present knowledge about the most common causes of VPI. METHODS Data sources include published reports over the past 20 years derived from computerized databases and bibliographies of pertinent articles and books. Indexing terms(More)
The following statements summarize our interpretation of the literature regarding submucous cleft palate: Incidence and Diagnosis of Submucous Cleft Palate 1. In surveys of classic stigmata of submucous cleft palate among the general population, the incidence has been reported to be 0.02 to 0.08 percent. In the larger of these series, the incidence of(More)
To investigate early effects of beta-amyloid (Aβ) on neuronal function, elderly normal controls (NCs, age range 58-97) were scanned with Pittsburgh Compound-B (PIB) positron emission tomography (a measure of Aβ) as well as functional magnetic resonance imaging (a measure of brain activation) while performing an episodic memory-encoding task of natural(More)
Amyloid-β, a hallmark of Alzheimer's disease, begins accumulating up to two decades before the onset of dementia, and can be detected in vivo applying amyloid-β positron emission tomography tracers such as carbon-11-labelled Pittsburgh compound-B. A variety of thresholds have been applied in the literature to define Pittsburgh compound-B positron emission(More)
The reinforcing and subjective effects of fentanyl, an opioid analgesic, were tested in ten healthy volunteers without histories of drug abuse, as a function of the temperature of a water bath in which the volunteers' forearms were immersed. The temperatures were body-temperature (37 degrees C), moderately cold (10 degrees C), and very cold (2 degrees C). A(More)
Carriers of the apolipoprotein E (APOE) ε4 allele, the major genetic risk for Alzheimer's disease (AD), harbor an increased load of β-amyloid (Aβ) plaque burden that is felt to be a major instigator of AD development. Data has suggested that lifestyle factors may reduce AD risk by directly mitigating Aβ pathology, which could be particularly beneficial in(More)
OBJECTIVE To assess the association between lifestyle practices (cognitive and physical activity) and β-amyloid deposition, measured with positron emission tomography using carbon 11-labeled Pittsburgh Compound B ([(11)C]PiB), in healthy older individuals. DESIGN Cross-sectional clinical study. SETTING Berkeley, California. PARTICIPANTS Volunteer(More)
Excessive consumption of alcohol is among the leading causes of preventable death worldwide. Although ethanol modulates a variety of molecular targets, including several neurotransmitter receptors, the neural mechanisms that underlie its rewarding actions and lead to excessive consumption are unknown. Studies in animals suggest that release of endogenous(More)