Tritium-labeled (E,E)-2,5-bis(4'-hydroxy-3'-carboxystyryl)benzene as a probe for β-amyloid fibrils

Accumulation of Aβ in the brains of Alzheimer disease (AD) patients reflects an imbalance between Aβ production and clearance from their brains. Alternative cleavage of amyloid precursor protein (APP) by processing proteases generates soluble APP fragments including the neurotoxic amyloid Aβ40 and Aβ42 peptides that assemble into fibrils and form plaques. Plaque-buildup occurs over an extended time-frame, and the early detection and modulation of plaque formation are areas of active research. Radiolabeled probes for the detection of amyloid plaques and fibrils in living subjects are important for noninvasive evaluation of AD diagnosis, progression, and differentiation of AD from other neurodegenerative diseases and age-related cognitive decline. Tritium-labeled (E,E)-1-[(3)H]-2,5-bis(4'-hydroxy-3'-carbomethoxystyryl)benzene possesses an improved level of chemical stability relative to a previously reported radioiodinated analog for radiometric quantification of Aβ plaque and tau pathology in brain tissue and in vitro studies with synthetic Aβ and tau fibrils.

A study of "broken appointment" patients in a children's hospital dental clinic

Part I of this study investigated possible variables determining "High Risk No Show" behavior on the part of patients in a dental clinic. Only "source of payment" seemed important; namely, that Medicaid patients were statistically more likely to be "High Risk No Show" patients (P less than .001). Race was associated but was found to be confounded with Medicaid. In an attempt to investigate the reasons for the Medicaid group being "High Risk No Show" patients, Part II of the study compared three distinct groups of patients at the Children's Hospital Medical Center Clinic. These included the self-paying group and the Medicaid group of the original sample of 90 in addition to the Union plan group (patients receiving free third-party payment care as an employee benefit). It was shown that both groups with third-party coverage were associated with "High Risk No Show" behavior. The type of "No Show" behavior, however, was different for the two groups. Union plan patients tended to cancel appointments or at least notify in advance of inability to keep an appointment. Medicaid patients, conversely, were just as likely to fail appointments and not file advance notice of inability to keep an appointment.