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Biomedical subjects

A Gleeson

Publications and source records attributed to A Gleeson.

15 recordsLinked to original sources
PubMed2003

Role of fibrin D-dimer testing in emergency medicine.

OBJECTIVES: Systemic values of the fibrinolytic plasma marker fibrin D-dimer are raised in a variety of acute clinical conditions. D-dimer values can now be rapidly determined and used to aid diagnosis in emergency medicine. However, despite clinical guidelines, inappropriate and unnecessary measurement of D-dimer values is a significant clinical problem. An understanding of the pathophysiological basis and limitations of the value of D-dimer values may help reduce this problem. This review discusses the pathophysiology of the fibrinolytic system. The currently used assays, clinical indications, and limitations of D-dimer measurement are reviewed. Finally, the potential future clinical indications for measurement of D-dimer values in emergency medicine are discussed. METHODS: Literature on D-dimer was identified from Medline, along with cross referencing from the reference lists of major articles on the subject RESULTS: and conclusions: Systemic D-dimer values aids diagnosis, and is potentially a prognostic indicator, in a variety of clinical conditions in emergency medicine. However, it has limited specificity in patients with comorbid conditions. Although, currently, there is no standard D-dimer assay, immunoturbidimetric assays are the most suitable for use in emergency medicine

Biomarkers↗
PubMed2002

Paediatric liver transplantation [corrected] in Melbourne: the first 50 patients.

To report the outcomes of the first 50 paediatric patients who have undergone liver transplantation (LT) at the Victorian Liver Transplant Unit, a retrospective review of case records was carried out. From December 1988 to December 2000, 108 patients 18 years or younger were referred for LT; 50 of these underwent a total of 53 transplants. The most common indications were biliary atresia (32%), metabolic disease (26%), and acute hepatic necrosis (26%). The majority of deaths (6/7) occurred in the 1st week after LT. The actuarial survival at 1 year was 88% (95% CI 75% to 94%) and at 10 years 85% (95% CI 71% to 93%). Survival rates were highest for children aged 3 to 14 years (95%) and lowest in those weighing less than 8 kg at the time of LT (66%). All 43 survivors are attending age-appropriate activities including kindergarten, school, and employment. The survival of patients undergoing LT in this unit compares favourably with those recorded by the Australia and New Zealand Transplant Registry and is commensurate with that reported by larger paediatric transplant programs overseas.

Adolescent↗
PubMed2000

The relationship between cholesterol absorption and intestinal cholesterol synthesis in the diabetic rat model.

The chylomicron remnant particle is thought to be particularly atherogenic and we have previously shown alterations in post-prandial lipoproteins which could contribute to their atherogenicity. Cholesterol metabolism is disturbed in diabetes, yet the effect of diabetes on intestinal cholesterol synthesis and absorption has rarely been investigated. The aim of this study was to examine cholesterol absorption and intestinal synthesis of cholesterol in the streptozotocin diabetic rat. Twelve diabetic rats were paired with 12 control rats. [14C]-Cholesterol emulsion was administered and the lymph duct was canulated. Lymph was collected for 4h. At sacrifice blood was taken for plasma lipoprotein measurements. Chylomicrons were prepared from the lymph by ultracentrifugation and [14C]-cholesterol content was determined by liquid scintillation counting. Lymph apolipoprotein B48 was isolated by gradient gel electrophoresis, and quantified by densitometric scanning. Serum triglyceride and cholesterol were greatly elevated in diabetic compared to control animals (260+/-90 and 9.8+/-8.0 mg/ml vs. 1.0+/-0.4 and 0.6+/-0.3 mg/ml, p < 0.0001 respectively). Lymph chylomicron apo B48 was similar in the two groups. Cholesterol absorption was not significantly different in diabetic compared to control rats but cholesterol synthesis was significantly higher in the diabetic animals (550+/-352 vs. 322+/-113 microg/h p < 0.03). There was a positive correlation between apo B48 and cholesterol absorption (r = 0.70, p < 0.01) in the diabetic rats and control rats (r = 0.71, p < 0.01) but no correlation between apo B48 and cholesterol synthesis in either group. This study demonstrates that cholesterol synthesis was increased in diabetes whereas cholesterol absorption was unaffected suggesting that intestinal cholesterol synthesis made an important contribution to the hypercholesterolaemia seen in the diabetic animals.

Animals↗
PubMed1999

The role of microsomal triglyceride transfer protein and dietary cholesterol in chylomicron production in diabetes.

AIMS/HYPOTHESIS: The aim of this study was to examine factors involved in chylomicron production in the streptozotocin diabetic rat, our hypothesis being that the synthesis of the chylomicron is abnormal in diabetes. METHODS: Diabetic rats (n = 20) were paired with control rats (n = 20). Cholesterol emulsion was given by gavage and the lymph duct was cannulated. Lymph was collected for 4 h. Chylomicrons were prepared from the lymph by ultracentrifugation. Lymph apolipoprotein B48 was isolated by gradient gel electrophoresis and quantified by densitometric scanning. Intestinal microsomal triglycerol transfer protein mRNA was measured by solution hybridisation nuclease protection, using a rat specific [32P]-labelled cRNA probe. RESULTS: Serum triglyceride and cholesterol were greatly increased in diabetic compared with control animals (258 +/- 77 and 8.9 +/- 6.4 mg/ml vs 1.04 +/- 0.37 and 0.54 +/- 0.03 mg/ml, p < 0.0001). Lymph chylomicron triglyceride and cholesterol were also higher in diabetic rats (29.4 +/- 27.3 and 0.28 +/- 0.3 mg/h vs 16.8 +/- 10.6 and 0.18 +/- 0.09 mg/h, p < 0.05). Lymph chylomicron apo B48 was similar in the two groups. Intestinal microsomal triglycerol transfer protein mRNA was higher in the diabetic rats (12.6 +/- 3.2 vs 3.8 +/- 3.0 amol/microgram RNA, p < 0.0001) and there was a positive correlation between lymph triglyceride and microsomal triglycerol transfer protein mRNA in the whole group (r = 0.65, p < 0.01). CONCLUSION/INTERPRETATION: The study shows that microsomal triglycerol transfer protein mRNA is raised in diabetes without an increase in apolipoprotein B48 in the lymph suggesting that microsomal triglycerol transfer protein regulates chylomicron triglyceride content but not particle number.

Animals↗
PubMed1997

Heparan sulfate proteoglycan-mediated uptake of apolipoprotein E-triglyceride-rich lipoprotein particles: a major pathway at physiological particle concentrations.

We explored potential mechanisms of non-low-density lipoprotein (LDL) receptor-mediated uptake of triglyceride-rich particles (TGRP) in the presence of apolipoprotein E (apo E). Human fibroblasts were incubated with model intermediate-density lipoprotein- (IDL-) sized TGRP (10-1000 microg of neutral lipid/mL) containing apo E. The extent of receptor-mediated uptake of TGRP was assessed with (a) an anti-apo E monoclonal antibody, which blocks receptor interaction; (b) incubation with heparin; (c) normal vs LDL receptor-negative fibroblasts; and (d) receptor-associated protein (RAP) to determine the potential contribution of LDL receptor-related protein (LRP). Cell surface heparan sulfate proteoglycan- (HSPG-) mediated uptake was examined with or without the addition of heparinase and heparitinase to cell incubation mixtures. At low particle concentrations (</=100 microg of neutral lipid/mL), almost all apo E-TGRP uptake was via the LDL receptor. At higher particle concentrations, within the physiologic range (>250 microg of neutral lipid/mL), most (>/=60%) particle uptake and internalization was via HSPG-mediated pathways. This HSPG pathway did not involve classical lipoprotein receptors, such as LRP or the LDL receptor. These data suggest that in peripheral tissues, such as the arterial wall, apo E may act in TGRP as a ligand for uptake not only via the LDL receptor and LRP pathways but also via HSPG pathways that are receptor-independent. Thus, at physiologic particle concentrations apo E-TGRP can be bound and internalized in certain cells by relatively low affinity but high capacity HSPG-mediated pathways.

Antibodies, Monoclonal↗
PubMed1997

Circulating anti-(xanthine oxidoreductase) antibodies in healthy human adults.

Levels of free anti-(xanthine oxidoreductase) (XOR) antibodies in the serum of normal healthy human subjects were determined, using both human and bovine enzyme as antigen, in an enzyme-linked immunosorbent assay (ELISA). Levels of IgM class anti-(human XOR) antibodies were found to be particularly high (mean values representing approximately 3% of total IgM) and to be significantly higher than levels of IgM anti-(bovine XOR) antibodies, indicating that endogenous XOR, rather than ingested bovine milk XOR, is the immunogen. IgM anti-XOR antibody levels were significantly higher in women under 50 years than in age-matched men, or in older women. Levels of IgG class anti-XOR antibodies were much lower and showed no correlation with gender or age. Affinity-purified anti-(human XOR) antibodies only partially inhibited enzymic activities of XOR. The majority of both IgM and IgG anti-(human XOR) antibodies in serum occurred as immune complexes, suggesting that the specific antibodies have a protective role in removing potentially damaging XOR from the circulation.

Adult↗
PubMed1997

Use of A&E wards.

Explore the source record for details and available documents.

Emergency Service, Hospital↗
PubMed1996

Sterol esterification in yeast: a two-gene process.

Unesterified sterol modulates the function of eukaryotic membranes. In human cells, sterol is esterified to a storage form by acyl-coenzyme A (CoA): cholesterol acyl transferase (ACAT). Here, two genes are identified, ARE1 and ARE2, that encode ACAT-related enzymes in yeast. The yeast enzymes are 49 percent identical to each other and exhibit 23 percent identity to human ACAT. Deletion of ARE2 reduced sterol ester levels to approximately 25 percent of normal levels, whereas disruption of ARE1 did not affect sterol ester biosynthesis. Deletion of both genes resulted in a viable cell with undetectable esterified sterol. Measurements of [14C]acetate incorporation into saponified lipids indicated down-regulation of sterol biosynthesis in the are1 are2 mutant cells. With the use of a consensus sequence to the yeast and human genes, an additional number of the ACAT gene family was identified in humans.

Acetates↗
PubMed1994

Apoprotein B structure and receptor recognition of triglyceride-rich low density lipoprotein (LDL) is modified in small LDL but not in triglyceride-rich LDL of normal size.

We compared the effect of lipid composition and particle size of triglyceride-rich low density lipoprotein (LDL) upon apoprotein B conformation and binding to the LDL receptor. Three groups of triglyceride-rich LDL were studied: (a) LDL isolated from chronic hypertriglyceridemic individuals (HTG-LDL); (b) normal LDL made triglyceride-rich by in vitro incubation with triglyceride emulsion and the neutral lipid transfer protein (R-LDL); and (c) LDL from normolipidemic individuals made acutely hypertriglyceridemic by intravenous infusion of 10% Intralipid (IV-LDL). HTG-LDL was small and dense, whereas R-LDL and IV-LDL had normal size. HTG-LDL, but not R-LDL or IV-LDL, exhibited decreased binding to the LDL receptor on human skin fibroblasts in studies at 4 degrees C and reduced degradation at 37 degrees C. Apoprotein B conformation was assessed by circular dichroism and by analyzing the immunoreactivity of different monoclonal antibodies. HTG-LDL but not R-LDL or IV-LDL showed a change in the CD spectra and a consistent decrease in the immunoreactivity of monoclonal antibody 3F5 (2.5-fold) which recognizes an epitope adjacent to the receptor binding domain of apoprotein B. These findings suggest that in triglyceride-rich LDL, the relative content of neutral lipid in the core of LDL in the absence of changes in the size of the particle does not significantly affect apoprotein B conformation or its affinity for the LDL receptor.

Antibodies, Monoclonal↗
PubMedDate not supplied

The effect of patient position on the reproducibility of cardiac output measurements.

OBJECTIVE: To determine the effect of patient position on the reproducibility of cardiac output measurements. DESIGN: Prospective, two-group quasi-experimental design. Convenience sample. SETTING: The study involved two intensive care units in two adult acute care hospitals. PATIENTS: Thirty patients admitted to the intensive care unit who had a thermodilution pulmonary artery catheter in place. Ages ranged from 39 to 80 years (mean of 66.4 +/- 11.3 years). OUTCOME MEASURES: Thermodilution cardiac output measurements. INTERVENTION: The subjects were placed in one of two groups, initially by flipping a coin then into alternate groups. Group A subjects were placed supine, and after 5 minutes had cardiac output measurements performed. They were then placed in the 45-degree upright position, and after an additional 5 minutes had cardiac output measurements performed. Group B subjects were first placed in the 45-degree upright position, and after 5 minutes had cardiac output measurements performed. They were then placed in the supine flat position, and after an additional 5 minutes had cardiac output measurements performed. RESULTS: Seventy percent (n = 30) of the sample population displayed a lower cardiac output in the 45-degree upright position than that obtained in the supine position, with the decrease ranging from 1% to 32% (mean decrease 11%). Forty percent (n = 30) of cardiac output measurements obtained in the 45-degree upright were greater than or equal to 10% less than those obtained in the supine flat position. The differences in cardiac output were analyzed with the paired t test. which produced a 95% confidence interval from -0.539 to -0.083. The two-group Wilcoxon test was used to analyze the mean cardiac output with the patient in the supine, flat position and in the 45-degree upright position. The mean cardiac output at 0 degrees was found to be statistically significant higher (p = 0.0083) than the mean cardiac output at 45 degrees. The effect of coexisting variables was analyzed with the Kruskal-Wallis. The use of vasoconstrictors was the only variable that had a statistically significant change in cardiac output associated with a change in position. CONCLUSIONS: These results indicate that cardiac output measurements are affected by alterations in patient position. To ensure accurate comparisons between consecutive cardiac output measurements, the researchers recommend that the position in which the cardiac output measurements are performed be documented and the cardiac output measurements be conducted in a uniform position.

Adult↗
PubMedDate not supplied

Hairdryer syncope.

Six cases of hairdryer syncope are presented. This is a recurrent phenomenon, never previously described in medical literature, though it has been recognised for some time by some hairdressers. Elderly ladies sit under hood hairdryers at hairdressing salons for periods of up to 30 minutes. We observed that under these circumstances, some ladies attended the Accident and Emergency department with a history of 'fainting'. A brief survey of hairdressers was conducted around the Stockport area. Possible causes of hairdryer syncope are discussed.

Aged↗