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Biomedical subjects

Pamela Shaw

Publications and source records attributed to Pamela Shaw.

8 recordsLinked to original sources
PubMed2006

Monoclonal antibodies that target pathological assemblies of Abeta.

Amyloid beta (Abeta) immunotherapy for Alzheimer's disease has shown initial success in mouse models of Alzheimer's disease and in human patients. However, because of meningoencephalitis in clinical trials of active vaccination, approaches using therapeutic antibodies may be preferred. As a novel antigen to generate monoclonal antibodies, the current study has used Abeta oligomers (amyloid beta-derived diffusible ligands, ADDLs), pathological assemblies known to accumulate in Alzheimer's disease brain. Clones were selected for the ability to discriminate Alzheimer's disease from control brains in extracts and tissue sections. These antibodies recognized Abeta oligomers and fibrils but not the physiologically prevalent Abeta monomer. Discrimination derived from an epitope found in assemblies of Abeta1-28 and ADDLs but not in other sequences, including Abeta1-40. Immunoneutralization experiments showed that toxicity and attachment of ADDLs to synapses in culture could be prevented. ADDL-induced reactive oxygen species (ROS) generation was also inhibited, establishing this response to be oligomer-dependent. Inhibition occurred whether ADDLs were prepared in vitro or obtained from Alzheimer's disease brain. As conformationally sensitive monoclonal antibodies that selectively immunoneutralize binding and function of pathological Abeta assemblies, these antibodies provide tools by which pathological Abeta assemblies from Alzheimer's disease brain might be isolated and evaluated, as well as offering a valuable prototype for new antibodies useful for Alzheimer's disease therapeutics.

Alzheimer Disease↗
PubMed2006

Locus coeruleus neurofibrillary degeneration in aging, mild cognitive impairment and early Alzheimer's disease.

Neurofibrillary degeneration in the nucleus basalis and a loss of its cortical cholinergic projections are prominent components of the neuropathology in Alzheimer's disease (AD). The AD brain is also associated with a degeneration of the noradrenergic projections arising from the nucleus locus coeruleus (LC), but the time course of this lesion is poorly understood. To determine whether the LC displays neurofibrillary abnormalities early in the course of events leading to AD, we examined tissue specimens from seven cognitively normal controls and five subjects at the stages of mild cognitively impairment (MCI) or early AD. Tyrosine hydroxylase immunochemistry was used as a marker of LC neurons while AT8 immunolabeling visualized abnormal tau associated with neurofibrillary tangles and their precursors. Thioflavine-S was used as a marker for fully developed tangles. We found that AT8-positive labeling and thioflavine-S positive tangles were present in both groups of specimens. However, the percentage of neurons containing each of these markers was significantly higher in the cognitively impaired group. The MMSE scores displayed a negative correlation with both markers of cytopathology. These results indicate that cytopathology in the LC is an early event in the age-MCI-AD continuum and that it may be listed among the numerous factors that mediate the emergence of the cognitive changes leading to dementia.

Acetylcholinesterase↗
PubMed2004

Cholinergic nucleus basalis tauopathy emerges early in the aging-MCI-AD continuum.

The cholinergic denervation in Alzheimer's disease (AD) provides the rationale for treatments with anticholinesterases. The presence of this cholinergic lesion is solidly established in advanced AD. Whether it also exists in early disease remains unsettled. This question was addressed with thioflavin-S histofluorescence to identify neurofibrillary tangles (NFT) and two tau antibodies (AT8, Alz-50) to identify pre-tangle cytopathology in the nucleus basalis, the source of cortical cholinergic innervation. Methods for the concurrent visualization of tauopathy and choline acetyltransferase were used to determine if the cytopathology was selectively located within cholinergic neurons. Five elderly index cases who had died at the stage of mild cognitive impairment (MCI) or early AD were identified by longitudinal neuropsychological and behavioral assessments. They were compared to 7 age-matched cognitively normal subjects. NFT and AT8 (or Alz-50) immunostaining in cholinergic nucleus basalis neurons existed even in the cognitively normal subjects. The percentage of tauopathy-containing nucleus basalis neurons was greater in the cognitively impaired and showed a significant correlation with memory scores obtained 1-18 months prior to death. These results show that cytopathology in cortical cholinergic pathways is a very early event in the course of the continuum that leads from advanced age to MCI and AD.

Acetylcholine↗
PubMed2004

Amyotrophic lateral sclerosis: a consensus viewpoint on designing and implementing a clinical trial.

In November 2002, an advisory board meeting was convened by Novartis Pharma to provide recommendations and rationale for clinical trials designed to evaluate new treatments, such as TCH346, for amyotrophic lateral sclerosis (ALS). In terms of selecting appropriate outcome measures, the panel recommended the use of the ALS Functional Rating Scale (ALSFRS-R) to measure primary endpoints. A review of other key issues in this area including regional variations in the epidemiology, diagnosis and management of ALS, defining patient populations and doses of trial medication, and accommodating the likelihood of co-medication with pre-existing treatment in trial design, are discussed.

Amyotrophic Lateral Sclerosis↗
PubMed2003

Reshaping health care delivery for adolescent parents: healthy steps and telemedicine.

Healthy Steps over Telemedicine uses telemedicine technology to bring child development services to adolescent parents in an urban school district. Videoconferencing units link teen parents at a Kansas City high school to developmental specialists and physicians at the Kansas University Medical Center (KUMC). Program participants receive developmental services and valuable health care information without leaving the school. The Healthy Steps goals are to educate parents about health care issues and to help them access medical care for their children and themselves. The telehealth goals are to implement the established Health Steps program effectively over the new medium. This article describes the process of delivering Healthy Steps services via telemedicine, specifically, selection and description of the site, selection of the technology, services provided, research evaluation, and lessons learned.

Adolescent↗
PubMed2002

Widely spread butyrylcholinesterase can hydrolyze acetylcholine in the normal and Alzheimer brain.

BACKGROUND: Butyrylcholinesterase (BChE), also known as the "pseudo" or "non-neuronal" cholinesterase, is traditionally thought to have a restricted CNS distribution and to play little, if any, role in cholinergic transmission. OBJECTIVE: To reanalyze the role of BChE in the human brain with more sensitive methodology. METHODS: Three brains were examined with acetylcholinesterase and BChE histochemistry. The sections were examined with bright- and dark-field microscopy. RESULTS: The histochemical parameters used in the present experiments showed that BChE activity was present in all hippocampal and temporal neocortical areas known to receive cholinergic input. At all of these locations, the BChE enzyme could hydrolyze the acetylcholine surrogate acetylthiocholine. A substantial portion of the hippocampal and neocortical BChE appeared to be located within neuroglia and their processes. CONCLUSIONS: Butyrylcholinesterase may have a greater role in cholinergic transmission than previously surmised, making BChE inhibition an important therapeutic goal in Alzheimer's disease. The results also suggest that the role of neuroglia in cholinergic transmission may be analogous to their well known role in glutamatergic transmission.

Acetylcholine↗
PubMed2002

Prostate-specific antigen testing in black and white men: an analysis of medicare claims from 1991-1998.

OBJECTIVES: To describe the trends in prostate-specific antigen (PSA) use and associated cancer detection among black and white Medicare beneficiaries older than 65 years during the calendar period from January 1991 through December 1998. METHODS: Medicare claims data were linked with cancer registry data from the Surveillance, Epidemiology and End Results program of the National Cancer Institute. Data from a 5% random sample of men without a diagnosis of prostate cancer were combined with data from prostate cancer cases diagnosed during the calendar period from 1991 to 1998. PSA tests conducted after a diagnosis of prostate cancer were excluded. RESULTS: PSA use has stabilized among white men, reaching an annual rate of 38% by 1995 and remaining at this level through 1998. The annual rate of use among black men reached 31% by 1998, but was still increasing at that time. By 1996, at least 80% of tests in both blacks and whites were second or later tests. By the end of 1996, 35% of white men and 25% of black men were undergoing testing at least biannually or more frequently. In 1996, 83% of diagnoses in whites and 77% in blacks were preceded by a PSA test. CONCLUSIONS: Older black men lag slightly behind older white men in their use of the PSA test; however, annual testing rates in blacks have yet to stabilize. In both race groups, an overwhelming majority of diagnoses are associated with a PSA test, whether for screening or diagnostic purposes. Regular screening rates in blacks are substantially lower than in whites, but the regular screening rates are relatively low in both race groups. Should PSA screening prove efficacious, efforts to promote regular use among both black and white men will likely be needed.

Black or African American↗