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Biomedical subjects

D Morgan

Publications and source records attributed to D Morgan.

339 records · Page 19Linked to original sources
PubMedDate not supplied

Correlation between cognitive deficits and Abeta deposits in transgenic APP+PS1 mice.

Doubly transgenic mAPP+mPS1 mice (15-16 months) had impaired cognitive function in a spatial learning and memory task that combined features of a water maze and a radial arm maze. Nontransgenic mice learned a new platform location each day during 4 consecutive acquisition trials, and exhibited memory for this location in a retention trial administered 30 min later. In contrast, transgenic mice were, on average, unable to improve their performance in finding the hidden platform over trials. The cognitive performance of individual mice within the transgenic group were inversely related to the amount of Abeta deposited in the frontal cortex and hippocampus. These findings imply that mAPP+mPS1 transgenic mice develop deficits in cognitive ability as Abeta deposits increase. These data argue that radial arm water maze testing of doubly transgenic mice may be a useful behavioral endpoint in evaluating the functional consequences of potential AD therapies, especially those designed to reduce Abeta load.

Alzheimer Disease↗
PubMedDate not supplied

Intrahippocampal LPS injections reduce Abeta load in APP+PS1 transgenic mice.

Multiple lines of evidence indicate that inflammatory processes are involved in the pathogenesis of Alzheimer's disease. Lipopolysaccharide (LPS) is widely used to induce inflammation in experimental systems. Consequently we injected LPS or saline intrahippocampally in 11 and 16 months old APP+PS1 transgenic mice to induce brain inflammation, then used immunocytochemistry to examine amyloid pathology 7 days later. As expected, LPS activated microglia as indicated by a significant increase in the area covered by major histocompatibility complex-II (MHC-II) immunostaining in the mice injected with LPS compared to the saline injected. Simultaneously, Abeta immunostaining showed an unexpected reduction of the Abeta load in the mice injected with LPS compared to the saline injected. This effect of LPS on the Abeta load in APP+PS1 mice strengthens the hypothesis that moderate amounts of microglial activation may be beneficial in Alzheimer's disease, by increasing the clearance of Abeta.

Amyloid beta-Peptides↗
PubMedDate not supplied

Concomitant sclerosing mesenteritis and bile duct fibrosis simulating Klatskin's tumor.

Sclerosing mesenteritis is an uncommon benign condition that should be included in the differential diagnosis of abdominal masses. We present the first reported case of this condition in association with idiopathic bile duct fibrosis simulating Klatskin's tumor. A review of the literature regarding both clinical entities is presented.

Bile Duct Neoplasms↗
PubMedDate not supplied

Ocular findings in HIV-1 positive and HIV-1 negative participants in a rural population-based cohort in Uganda.

PURPOSE: To report the ocular findings in HIV-1 seropositive individuals and HIV-negative controls in a population-based cohort in rural Uganda. METHODS: Participants were examined by an ophthalmologist, who was unaware of their HIV-status. RESULTS: 238 participants were examined, 43 were HIV-1 prevalent cases (infected prior to 1990); 62 were HIV-1 incident cases and 133 were HIV-negative controls. Eleven of the HIV-positive participants had AIDS, and a further 8 had a CD4 count of less than 200 cells/mm3. Bilateral low vision was recorded in 9 participants and cataracts were the main cause of bilateral low vision. The mean intra-ocular pressure (IOP) was 12.6 mm Hg, and no association was found between IOP and CD4 lymphocyte count. Although significantly more HIV positives had some sign of intraocular inflammation compared to the negatives (p = 0.02) there was no significant linear trend in the HIV positives with decreasing CD4 count. Overall, 11 (26%) prevalent, 6 (10%) incident cases and 8 (6%) HIV-negatives controls had some evidence of intraocular inflammation, however, only one person had reduced visual acuity attributable to these lesions. Punctate epithelial erosions and keratic precipitates in the anterior chamber were seen significantly more frequently in HIV-positives compared to the HIV-negative controls. Cotton wool spots were not seen. CONCLUSIONS: A substantial proportion of HIV-infected persons had ocular findings which may have been attributable to their infection, however in only one case did this result in reduced visual acuity. Although the ocular complications of AIDS seem to comprise a large extra element in the work load of tertiary care hospitals dealing with eye problems, on a population basis such cases are infrequent.

Adult↗
PubMedDate not supplied

A beta peptide vaccination prevents memory loss in an animal model of Alzheimer's disease.

Vaccinations with amyloid-beta peptide (A beta) can dramatically reduce amyloid deposition in a transgenic mouse model of Alzheimer's disease. To determine if the vaccinations had deleterious or beneficial functional consequences, we tested eight months of A beta vaccination in a different transgenic model for Alzheimer's disease in which mice develop learning deficits as amyloid accumulates. Here we show that vaccination with A beta protects transgenic mice from the learning and age-related memory deficits that normally occur in this mouse model for Alzheimer's disease. During testing for potential deleterious effects of the vaccine, all mice performed superbly on the radial-arm water-maze test of working memory. Later, at an age when untreated transgenic mice show memory deficits, the A beta-vaccinated transgenic mice showed cognitive performance superior to that of the control transgenic mice and, ultimately, performed as well as nontransgenic mice. The A beta-vaccinated mice also had a partial reduction in amyloid burden at the end of the study. This therapeutic approach may thus prevent and, possibly, treat Alzheimer's dementia.

Aging↗
PubMedDate not supplied

Potential effectiveness of quality assurance screening using large but imperfect databases.

To examine the effect of imprecise classification of patient risk (severity of illness) on an otherwise highly accurate quality assurance screening technique, data on clinical outcomes were generated for a simulated hospital system consisting of 108 facilities treating approximately 565,000 patients a year. In these simulations, marked differences in facility size, casemix distribution, and quality of care were combined with random variations in outcome. Pooled data for all 108 facilities were used to create algorithms that combined 468 discrete patient risk classifications into either ten or three groups with broad, overlapping ranges of patient-specific risks of unfavorable clinical results. When derived algorithms were applied to independently generated facility-specific data, the ability to identify hospital systems with and without quality of care problems was maintained with ten, but not with three, risk groups. However, even three moderately heterogeneous risk groups were sufficient to preserve a high degree of sensitivity and specificity in screening for potential quality of care problems within individual facilities. Thus, outcome-based quality assurance screening can be highly accurate in actual health care situations in which only imprecise estimations of patient-specific risk can be achieved.

Algorithms↗
PubMedDate not supplied

Anti-bovine viral diarrhoea virus antibodies in adult Zambian patients infected with the human immunodeficiency virus.

Bovine viral diarrhoea (BVD) virus is a cosmopolitan pestivirus of animals which is associated with diarrhoea, immunosuppression and synergy with other pathogens. This study was conducted to establish the prevalence of anti-BVD virus antibodies in healthy Zambian adults and those with asymptomatic and symptomatic HIV disease. Sera from 1159 adults were tested for anti-BVD virus antibodies using the indirect immunofluorescence test and the confirmatory Western blot. Of the 1159 sera examined, 180 (15.5%) showed significantly elevated titres of anti-BVD antibodies. These included 70 out of 477 (14.7%) HIV-negative healthy adults; 73 out of 480 (15.2%) of HIV-positive asymptomatic individuals; 23 out of 129 (17.8%) HIV-seropositive patients with associated illnesses excluding diarrhoea; and 14 out of 73 (19.2%) of HIV-seropositive patients with chronic diarrhoea. HIV-seropositive patients with chronic diarrhoea or associated illnesses appear to have significantly increased seroprevalence of anti-BVD virus antibodies (P = > 0.01). The mechanism of interaction between BVD virus and HIV infections and the synergistic effects with other opportunistic pathogens in humans requires definition.

Adult↗
PubMedDate not supplied

Foot growth rate in children age one to six years.

Previous guidelines suggested that children age 2 to 6 years require a shoe size change every 1 to 2 months. Our study of foot growth in 112 children enrolled in a prospective treatment protocol for flatfoot demonstrates that children age 12 to 30 months will require shoe size change every two to three months but that foot growth slows over the subsequent four years, necessitating shoe size change only every 4 months in children up to 4 years of age and every 6 months in children from age 4 to 6 years.

Adolescent↗
PubMedDate not supplied

Establishing a dressings formulary.

Choices have to be made between the multitude of dressings available, and especially between products with the same characteristics and features. This article describes how to compile, maintain, monitor and review a dressings formulary.

Bandages↗