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A D Roses

Publications and source records attributed to A D Roses.

At least 109 records · Page 6Linked to original sources
PubMed1997

Thymocytes and cultured thymic epithelial cells express transcripts encoding alpha-3, alpha-5 and beta-4 subunits of neuronal nicotinic acetylcholine receptors: preferential transcription of the alpha-3 and beta-4 genes by immature CD4 + 8 + thymocytes.

Thymic tissues express transcripts encoding the alpha-3, alpha-5 and beta-4 subunits of nicotinic neuronal acetylcholine receptors (AcChRs) suggesting that neuronal AcChRs similar to those expressed in ganglia are expressed in the thymus. Transcription occurs in both isolated thymocytes and thymic epithelial cells. RT-PCR analyses of thymocyte subsets indicate that immature CD4 + 8 + thymocytes express higher levels of the alpha-3 and beta-4 transcripts than more mature thymocytes. Compared to freshly isolated thymocytes, peripheral blood lymphocytes do not express alpha-3 and beta-4 AcChR subunit transcripts. Cultured thymocytes rapidly down-regulate transcription of the alpha-3 and beta-4 AcChR subunit genes by a process that is not reversed by stimulation with phytohemagglutinin and IL-2. Thus our results indicate that there is transcriptional regulation of neuronal AcChR subunit genes during the process of thymocyte maturation and that factors within the thymic microenvironment influence expression of the alpha-3 and beta-4 AcChR subunit genes by developing T cells.

Amyloid beta-Protein Precursor↗
PubMed1997

Confirmation of linkage of oculopharyngeal muscular dystrophy to chromosome 14q11.2-q13 in American families suggests the existence of a second causal mutation.

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset, autosomal dominant disorder characterized by progressive ptosis, dysphagia, and extremity weakness. Linkage of OPMD to 14q11.2-q13 has been reported in a series of French-Canadian families. Tightly linked markers have been defined and haplotype analysis in these data show a single segregating disease chromosome throughout the OPMD French-Canadian families. We have ascertained and sampled five multigenerational outbred American OPMD families. Four of the five families have known French-Canadian ancestry while the fifth is of English/Scottish origin. Linkage analysis was performed using standard likelihood methods. A peak multipoint lod score of 6.30 was obtained for the marker MYH7.1 in the OPMD families. The English/ Scottish family exhibited a different chromosomal haplotype for the OPMD alleles than the families of French-Canadian origin. These data suggest this family may represent a second, possibly independent mutation in this disorder. Linkage was confirmed to chromosome 14q11.2-q13 with no evidence of genetic heterogeneity.

Adult↗
PubMed1997

Apolipoprotein E genotyping as a diagnostic adjunct for Alzheimer's disease.

Positive predictive value (PPV) estimates how often a particular test predicts the eventual diagnosis, and it is the basis of any test that attempts to establish a diagnosis. Calculating the PPV depends directly on the entrance criteria for considering the diagnosis and the exit criteria of the generally accepted "gold standard" for establishing the ultimate diagnosis. For a relatively common disease such as AD, the practical usefulness of a diagnostic test also relates to the stage of the disease at which the test can be applied. An accurate and predictive test only has practical value when it can be used early in the course of the disease. Apolipoprotein E (Apo E) is the first genetic locus identified as a susceptibility polymorphism for a common complex disease using positional or candidate cloning strategies. There are three common alleles (epsilon 2 to epsilon 4) and six possible genotypes; about 30% of the population carries an epsilon 4 allele, each additional copy of which is associated with an increased risk of AD and earlier age of onset distribution. In patients with cognitive impairment of the Alzheimer type, who have been diagnosed with possible or probable AD, the presence of an Apo E-epsilon 4 allele is likely in more than 50% of patients for whom the PPV is greater than 97%. Apo E genotyping is the only diagnostic adjunct that has been subjected to rigorous measurements of specificity, sensitivity, PPV, and NPV. In the past, testing of dementia patients was directed at "ruling out" other treatable causes. Results from the initial studies of the PPV of Apo E genotyping for AD showed that the PPV of Apo E genotyping was greater than 97%. The paradigm for AD diagnosis is changing. Apo E genotyping can provide useful diagnostic information and that accuracy will improve as other susceptibility genetic risk factors are identified.

Aged↗
PubMed1997

Polyglutamine domains are substrates of tissue transglutaminase: does transglutaminase play a role in expanded CAG/poly-Q neurodegenerative diseases?

Huntington's disease and six other neurodegenerative diseases are associated with abnormal gene products containing expanded polyglutamine (poly-Q; Qn) domains (n > or = 40). In the present work, we show that glutathione S-transferase (GST) fusion proteins containing a small, physiological-length poly-Q domain (GSTQ10) or a large, pathological-length poly-Q domain (GSTQ62) are excellent substrates of guinea pig liver (tissue) transglutaminase and that both GSTQ10 and GSTQ62 are activators of tissue transglutaminase-catalyzed hydroxaminolysis of N-alpha-carbobenzoxyglutaminylglycine. The present findings have implications for understanding the pathophysiological mechanisms of expanded CAG/poly-Q domain diseases.

Amino Acid Sequence↗
PubMed1997

Apolipoprotein E-deficient mice have increased susceptibility to focal cerebral ischemia.

Recent evidence suggests that apolipoprotein E (ApoE) plays a role in neurologic disease. This experiment compared the neurologic and histologic outcome of ApoE-deficient mutant and wild-type mice subjected to a 60- or 90-minute episode of middle cerebral artery filament occlusion and a recovery interval of 24 hours. With 60 minutes of ischemia, there was no mortality. Apolipoprotein E-deficient mice had larger infarcts (cortex: ApoE deficient = 20 mm3 +/- 12, wild-type = 9 +/- 7 mm3, P = 0.03; subcortex: ApoE deficient = 22 +/- 7 mm3, wild-type = 16 +/- 7 mm3, P = 0.07). Hemiparesis was less severe in wild-type animals (P = 0.02). After 90 minutes of ischemia, mortality in ApoE-deficient mice (n = 10) was 40% versus 0% in wild-type mice (n = 10; P = 0.09). Intraparenchymal hemorrhage was found in 3 of the 4 dead mice. No difference in cortical (ApoE deficient = 37 +/- 8 mm3; wild-type = 31 +/- 18 mm3; P = 0.49) or subcortical (ApoE deficient = 30 +/- 11 mm3; wild-type = 32 +/- 18 mm3; P = 0.78) infarct volumes was present among survivors. ApoE-deficient mice had a prolonged activated partial thromboplastin time and increased fibrinogen concentration. This data supports the hypothesis that apolipoprotein E plays a role in the pathophysiology of ischemic brain damage.

Animals↗
PubMed1997

Apolipoprotein E-epsilon 2 and Alzheimer's disease: genotype influences pathologic phenotype.

To determine whether apolipoprotein E epsilon 2 (APOE-epsilon 2) affects neuropathology in aging and Alzheimer's disease (AD), we compared beta-amyloid plaque (A beta P) and neurofibrillary tangle densities, neuropil thread formation, and amyloid angiopathy in five APOE-epsilon 2/3 AD patients, five APOE-epsilon 3/3 AD patients, five APOE-epsilon control patients, and five APOE-epsilon 3/3 control patients. We examined the (frontal and parietal) neocortex, hippocampus, entorhinal cortex, and cerebellum and found A beta P densities to be lower (t = 3.121, p = 0.011) in the cortex of APOE-epsilon 2/3 AD patients than in APOE-epsilon 3/3 AD patients. Amyloid angiopathy was also less in APOE-epsilon 2/3 patients than in APOE-3/3 patients (U = 4.500, p = 0.027). Control APOE-epsilon 2/3 brains had little AD-related pathology; even our 102-year-old control case showed few A beta Ps compared with the elderly APOE-epsilon 3/3 cases. The APOE-epsilon 2/3 genotype may influence pathologic phenotype in some aged normal and AD populations.

Aged↗
PubMed1997

Beta-amyloid protein-containing inclusions in skeletal muscle of apolipoprotein-E-deficient mice.

The tibialis anterior muscle and soleus muscle of apolipoprotein-E-deficient mice were examined by light and electron microscopy. By light microscopy, sarcoplasmic inclusions were seen in tibialis anterior muscle and 40% of type 2 myofibers were affected in all animals over 8 months of age. These inclusions reacted for nonspecific esterase, cytochrome oxidase, and myoadenylate deaminase and were also periodic acid Schiff positive and stained basophilic with hematoxylin. Moreover, they reacted immunocytochemically with an antibody specific to fragment 17 to 24 of the published sequence of Alzheimer's cerebrovascular amyloid peptide. Immunoreactivity was lost when the antibody was adsorbed with the appropriate synthetic peptide. Ultrastructurally, the inclusions consisted of tubular arrays and were similar to those observed in human muscle in several pathological conditions. In type 1 myofibers of both tibialis anterior and soleus muscle, however, mitochondrial abnormalities including an increase in their number and size were detected, but tubular aggregates were not seen. These large mitochondria possessed an electron-dense inner chamber with an increased number of tightly packed cristae. The results obtained suggest that in these mice there is a disturbed lipid metabolism in skeletal muscle fibers that manifests itself with an accumulation of phospholipid in the form of sarcoplasmic reticulum tubules in the type 2 fibers and enlarged mitochondria with tightly packed cristae in the type 1 fibers. In addition, beta-amyloid protein was closely associated with the accumulated tubules and vesicles of sarcoplasmic reticulum and may represent dysregulation of amyloid precursor protein metabolism.

Amyloid beta-Protein Precursor↗
PubMed1997

Rapid brain autopsy. The Joseph and Kathleen Bryan Alzheimer's Disease Research Center experience.

OBJECTIVE: To develop a system for retrieving brain tissue within 1 hour after death in an effective and useful manner. DESIGN: Nurse clinicians were employed as study co-ordinators and were available to families 24 hours each day. SETTING: Autopsies were performed at Duke University Medical Center, Durham, NC, from 1985 through 1995. PARTICIPANTS: Neuropathology faculty, fellows, and residents, autopsy technicians; and brain bank staff. RESULTS: Fifty-one rapid autopsies with a postmortem interval of less than 1 hour have been performed. Four of these were normal controls, three were disease controls, and 44 represented Alzheimer's disease patients. Tissue retrieved at rapid autopsy has been distributed to 93 research teams, 30 of these located at Duke University Medical Center. Many researchers have received multiple shipments of tissue. CONCLUSIONS: The Bryan Alzheimer's Disease Research Center Rapid Autopsy Program at Duke University Medical Center has been successful in retrieving tissue from individuals with dementia and also from controls within 1 hour of death. The critical features of the success of this program have been the use of nurse clinicians who work closely with patients and their families to ensure a successful autopsy at the time of death and the maintenance of a 24-hour call schedule for nurses and neuropathology staff. Similar programs can be implemented for experimental work into the pathogenesis of a wide variety of human diseases in which the examination of human tissue is required.

Aged↗
PubMed1996

No association between alpha 1-antichymotrypsin and familial Alzheimer's disease.

Alzheimer's disease (AD) is the most common mid to late age-of-onset neurodegenerative disorder. AD has a strong and complex genetic etiology, and multiple genes, acting independently and/or interacting, likely affect the risk of developing AD. Several genes involved with AD already have been described, but only the APOE gene on chromosome 19q has been shown to affect the risk of the most common form of AD, occurring with onset over the age of 65. Because a substantial portion of late-onset AD is not explained by APOE, other genes affecting late-onset AD likely occur. These could act either independently or perhaps interact with APOE. alpha 1-Antichymotrypsin (ACT) is a major component of the amyloid plaques found in the brains of AD patients and may play a role in the pathophysiology of AD. It has been proposed that a specific polymorphism within the ACT gene interacts with APOE to increase the risk of developing AD. Our results do not confirm this finding.

Adult↗
PubMed1996

Apolipoprotein E and Alzheimer's disease. A rapidly expanding field with medical and epidemiological consequences.

The Alzheimer's Association and the National Institute on Aging sponsored a meeting of experts in Alzheimer's disease (AD), geneticists, social scientists, and ethicists in Chicago in October 1995 to discuss the use of apolipoprotein E (APOE) genotyping in Alzheimer's disease. A short scientific report was published in the scientific journal Lancet with recommendations from the group. Several areas were discussed, including: (1) the scientific basis for recommendations on the application and uses of APOE genotyping, (2) clarifying the clinical and epidemiological research that needs to done, (3) genetic counseling issues, (4) ethical and legal issues, and (5) potential uses of APOE genotyping for treatment care planning. This contribution was a general introduction to begin the meeting. The genetic association of APOE genotypes with the age of onset distribution and risk of Alzheimer's disease was reviewed. An analysis of the current applications for three distinctly different applications of APOE genotyping was presented with the following conclusions: (1) predictive testing for cognitively intact persons was not recommended; (2) APOE genotyping is a promising adjunct for use in the differential diagnosis of patients with dementia; and (3) APOE genotyping may have a use in selecting therapies; however, further prospective studies are necessary. There is no universal "APOE test for AD." A strong emphasis was made to avoid use of the term in making recommendations regarding APOE genotyping without specific reference to the type of application involved. The predictive testing of asymptomatic persons versus APOE genotyping as a diagnostic adjunct for symptomatic patients has been seriously confused in both the lay and clinical press. The former application is not recommended, but diagnostic usefulness early in clinical evaluations for dementia has been confirmed.

Age of Onset↗
PubMed1996

Early detection of Alzheimer's disease by combining apolipoprotein E and neuroimaging.

New treatments for Alzheimer's disease (AD) are more likely to slow or halt disease progression rather than to reverse existing neuronal damage. Identifying persons with mild cognitive complaints who are at risk for AD will allow investigators to apply anti-dementia treatments before extensive brain damage develops. The discovery of the apolipoprotein E epsilon 4 allele (APOE epsilon 4) as a major risk factor for AD offers promise of assisting in early detection and prediction of Alzheimer's disease, particularly when genetic assessments are combined with other biomarkers such as neuroimaging. Studies of relatives at risk for familial AD using neuroimaging (positron emission tomography [PET]) and genetic assessments of APOE suggest that at-risk relatives with APOE epsilon 4 have lower parietal metabolism than those without APOE epsilon 4. Additional techniques that might increase sensitivity and specificity include longitudinal assessment of clinical and brain functional change, pharmacological challenges of short-acting anticholinergic agents, and memory activation paradigms during functional scanning. Such strategies should eventually assist in early detection of AD and in vivo therapeutic monitoring of brain function during experimental anti-dementia treatment trials.

Adult↗
PubMed1996

Toxicity of expanded polyglutamine-domain proteins in Escherichia coli.

Five neurodegenerative diseases are caused by proteins with expanded polyglutamine domains. Toxicity of these proteins has been previously identified only in mammals, and no simple model systems are available. In this paper, we demonstrate in E. coli that long polyglutamine domains (59-81 residues) as GST-fusion proteins inhibit growth while smaller glutamine (10-35 residues) or polyalanine (61 residues) domains have no effect. Analogously in humans, polyglutamine repeats less than 35-40 glutamines produce a normal phenotype, while expansion greater than 40 glutamines is always associated with disease. Expression of polyglutamine proteins in E. coli may help identify the molecular mechanism of pathogenesis of CAG trinucleotide repeat diseases and be a useful screen to identify potential therapeutic compound.

Amino Acid Sequence↗
PubMed1996

No association between very low density lipoprotein receptor (VLDL-R) and Alzheimer disease in American Caucasians.

The very low density lipoprotein receptor gene (VLDL-R) is a receptor for apolipoprotein-epsilon (APOE)-containing lipoproteins, and thus has been suggested as a possible risk factor for Alzheimer disease (AD). Recently, Okuizumi et al. [Nature Genet, II (1995) 207-209] reported an association between the 96 bp allele at the VLDL-R locus and AD in a Japanese population. The association resulted in a two-fold increase of risk that decreased with increasing age. We have examined this association in 316 Caucasian sporadic AD patients, comparing their findings to 160 Caucasian AD spouse controls. We also investigated 53 late-onset Caucasian AD families for association and linkage. Our data failed to confirm linkage and/or association to the VLDL-R locus. Stratification by age at onset or APOE genotype also failed to show significant results.

Adult↗