The diagnosis of esophageal cancer by 2-deoxy-2-F-18 fluoro-D-glucose positron emission tomography (F-18 FDG PET).
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Biomedical subjects
Publications and source records attributed to James Robert Brasić.
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(+)-Amphetamine, (+/-)-ephedrine, and phentermine are commonly used appetite suppressants that release monoamines from nerve cells by acting as substrates for biogenic amine transporters. One key difference among the three drugs is their selectivity for norepinephrine (NE) release vs. dopamine (DA) release. The NE/DA selectivity ratios for these drugs as determined in vitro [(EC50 NE(-1))/(EC50 DA(-1))] are (+/-)-ephedrine (18.6) > phentermine (6.7) > (+)-amphetamine (3.5). The in vitro data suggest that when administered in vivo, these stimulants might differ in their ability to release DA from nerve terminals in the brain. To test this hypothesis, noradrenergic effects (i.e., plasma NE) and dopaminergic effects (i.e., central DA release) were assessed when each drug was administered intravenously (1.5 mg/kg) to anesthetized baboons. Central DA release was determined via positron emission tomography using the method of [11C]raclopride displacement. In the present investigation, high doses of these stimulants increased plasma NE and DA in parallel, but only (+)-amphetamine released central DA from neurons and decreased plasma prolactin. None of the drugs altered plasma amine metabolite levels, indicating no inhibition of monoamine oxidase activity at the administered doses. Plasma drug levels measured in baboons were higher than those measured in human patients taking prescribed doses of the drugs. Viewed collectively, the present data indicate that typical clinical doses of phentermine and (+/-)-ephedrine may not release central DA in humans, a hypothesis that should ultimately be tested in controlled clinical studies.
The comparison of the ethnic composition of an intermediate care facility with several Hispanic residents and the general population was hindered by the absence of categorization of ethnicity according to the United States Census. If all Hispanic residents of the facility were white, then 55% of the facility population were white, a proportion comparable to the 58.2% white population of the general population. On the other hand, if all the Hispanic residents were not white, then 27.5% of the facility residents were white. In that case, the proportion of white residents of the facility is much less than in the general population. Therefore, a Demographic Coding Form was developed to capture the essential data to make direct comparisons and contrasts with the general population recorded by the United States Census. Since the United States Census records Hispanic ethnic minority status as a separate category independent from all other ethnic groups, the design of experiments to investigate the possible effects of ethnicity on populations wisely incorporates the administration of a Demographic Coding Form to capture the key ethnic data to permit direct comparison with the general population.
Although the risk of the eventual development of tardive dyskinesia and other persistent adverse effects of neuroleptics is high, among adults with mental retardation and other developmental disabilities, neuroleptics may ameliorate dyskinesias, aggression, and inattention. The effects of traditional neuroleptics on a comparable population of children and adolescents with mental retardation and other developmental disabilities are unknown. The objective of this study was to develop an assessment battery to describe the effects of traditional neuroleptics on the behavior and movements of a small sample of children and adolescents with mental retardation and other developmental disabilities. 13 children and adolescents aged 6 to 16 years attending a developmental disabilities clinic were evaluated utilizing a Movement Assessment Battery to measure behavior and motions. Five subjects took traditional neuroleptic medications. Trained raters can reliably assess the movements and behaviors of children and adolescents with multiple handicaps. Children and adolescents with developmental disabilities may be vulnerable to experience functional impairment and akathisia, tics, and other dyskinesias when administered traditional neuroleptic medications.
For the quantitative analysis of ligand-receptor dynamic positron emission tomography (PET) studies, it is often desirable to apply reference tissue methods that eliminate the need for arterial blood sampling. A common technique is to apply a simplified reference tissue model (SRTM). Applications of this method are generally based on an analytical solution of the SRTM equation with parameters estimated by nonlinear regression. In this study, we derive, based on the same assumptions used to derive the SRTM, a new set of operational equations of integral form with parameters directly estimated by conventional weighted linear regression (WLR). In addition, a linear regression with spatial constraint (LRSC) algorithm is developed for parametric imaging to reduce the effects of high noise levels in pixel time activity curves that are typical of PET dynamic data. For comparison, conventional weighted nonlinear regression with the Marquardt algorithm (WNLRM) and nonlinear ridge regression with spatial constraint (NLRRSC) were also implemented using the nonlinear analytical solution of the SRTM equation. In contrast to the other three methods, LRSC reduces the percent root mean square error of the estimated parameters, especially at higher noise levels. For estimation of binding potential (BP), WLR and LRSC show similar variance even at high noise levels, but LRSC yields a smaller bias. Results from human studies demonstrate that LRSC produces high-quality parametric images. The variance of R(1) and k(2) images generated by WLR, WNLRM, and NLRRSC can be decreased 30%-60% by using LRSC. The quality of the BP images generated by WLR and LRSC is visually comparable, and the variance of BP images generated by WNLRM can be reduced 10%-40% by WLR or LRSC. The BP estimates obtained using WLR are 3%-5% lower than those estimated by LRSC. We conclude that the new linear equations yield a reliable, computationally efficient, and robust LRSC algorithm to generate parametric images of ligand-receptor dynamic PET studies.
Accurate identification of the demographic characteristics of subjects is crucial for clinical, research, teaching, and administrative purposes in psychology. The Demographic Coding Form is a simple, self-report tool to identify essential demographic data. Secondary categorization as "Hispanic" is obtained to facilitate comparison with the general population data. The form requests information about ethnic mixtures in subjects. Psychometric properties are being elucidated.
A mentor is the key person to assist a student who wishes to become an independent investigator. The federal government provides long-term funding for decades of research by an investigator, and short-term funding for years of transition from student to investigator is available from both governmental and private agencies. Grants designed for men and women and various ethnic groups are valuable resources. Courteous acknowledgment of sponsorship by the grantee facilitates continued grants from the funding source.
Although the United States Food and Drug Administration banned its use for nocturnal leg cramps due to lack of safety and efficacy, quinine is widely available in beverages including tonic water and bitter lemon. Numerous anecdotal reports suggest that products containing quinine may produce neurological complications, including confusion, altered mental status, seizures, and coma, particularly in older women. Psychologists need to inquire about consumption of quinine-containing beverages as part of an evaluation process.
To study alcohol's effects on the structure and function of the brain in living human beings, researchers can use various imaging techniques. Positron emission tomography (PET) is a functional imaging approach used to study the metabolism and physiology of the brain. PET studies have found that both acute and chronic alcohol ingestion alter blood flow and metabolism in various brain regions, including the frontal lobes and cerebellum. Other analyses focusing on alcohol's effects on brain chemical (i.e., neurotransmitter) systems have found that both acute and chronic alcohol consumption alter the activities of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) and the excitatory neurotransmitters glutamate, dopamine, and serotonin. These alterations may contribute to the reinforcing and rewarding effects of alcohol as well as to symptoms of alcohol withdrawal. Imaging studies also have demonstrated that some of alcohol's adverse effects on brain function can be reversed by abstinence or alcoholism treatment interventions. In addition, imaging studies may help in the development of new medications for alcoholism treatment.
The beneficial and adverse effects of pets on people with special mental and physical conditions merit inclusion in psychological evaluations and treatments.