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Biomedical subjects

S E Dunn

Publications and source records attributed to S E Dunn.

30 records · Page 2Linked to original sources
PubMed1996

Development of a Comprehensive Surgical Information System at Madigan Army Medical Center.

The Operative Registry (DA Form 4108) has been the information source for surgical data supporting quality assurance and utilization review efforts at Madigan Army Medical Center. Recently, Madigan's requirements for data and reporting changed. Like other government medical facilities, Madigan began pervasive quality-improvement efforts. This resulted in new ideas to measure hospital performance. Consequently, requirements for surgical data required to support quality and resource management reporting, utilization review, residency review reporting, research and credentialing changed. This article details Madigan's approach to addressing these requirements via development of a comprehensive computing solution. It discusses Madigan's fragmented data environment before system development, and gives the reader perspective on the decision-making process that led to system development rather than purchasing a commercial product. Finally, the article describes how a strong partnership between staff and developers was key to providing a solution that exceeded established goals.

Hospitals, Military↗
PubMed1994

Hypocholesterolemic properties of plant indoles. Inhibition of acyl-CoA:cholesterol acyltransferase activity and reduction of serum LDL/VLDL cholesterol levels by glucobrassicin derivatives.

Studies were undertaken to investigate the effects of the plant compound indole-3-carbinol (I3C) and its acid condensation products, which are generated in the stomach following ingestion of I3C, on cholesterol homeostasis in mice. Individual acid condensation products were synthesized and purified by HPLC. In vitro experiments revealed that several of the acid condensation products effectively inhibited the enzyme acyl-CoA:cholesterol acyltransferase (ACAT), which is responsible for the conversion of free cholesterol to the cholesteryl ester, at micromolar concentrations. Since the inhibition of ACAT in vivo should reduce serum cholesterol levels, I3C was administered to mice, and the effects on serum cholesterol levels were evaluated. Total serum cholesterol levels were elevated by 29% in mice provided a 3% cholesterol-supplemented diet, but this elevation was attenuated significantly (P < or = 0.05) by approximately 50% when I3C (100 mg/kg/day) was added to this diet. This effect of I3C was entirely on low density lipoprotein (LDL)/very low density lipoprotein (VLDL) cholesterol, which was lowered significantly (P < or = 0.05) by approximately 30%. In summary, I3C lowered serum LDL/VLDL cholesterol levels in mice, and this effect was likely mediated by the inhibition of ACAT by some of the acid condensation products of I3C. These results provide a possible mechanism by which I3C-rich vegetables lower serum cholesterol levels.

Animals↗
PubMed1994

Effect of the plant compound indole-3-carbinol on hepatic cholesterol homoeostasis.

The aim of this study was to elucidate the effects of the compound indole-3-carbinol (I3C), which is found in cruciferous vegetables, on hepatic cholesterol homoeostasis and metabolism in male CD-1 mice. Oral administration of 500 and 750 mg I3C/kg/day to mice for 1 wk resulted in increased liver mass and microsomal protein content. Hepatic microsomal cholesterol levels were not significantly altered following treatment with 100 and 250 mg I3C/kg/day, but were significantly decreased following treatment with 500 and 750 mg/kg/day. Conversely, the lower doses of I3C administered decreased serum cholesterol levels whereas the higher doses of I3C had no effect on this parameter. Alterations in cholesterol homoeostasis by I3C were not related to liver hypertrophy, since administration of phenobarbital to mice increased liver size, but had no significant effect on hepatic microsomal or serum cholesterol levels. Activities of the hepatic enzymes cholesterol ester hydrolase and cholesterol 7 alpha-hydroxylase were not altered by I3C. However, 500 and 750 mg I3C/kg/day elevated the activity of hepatic acyl-CoA:cholesterol acyltransferase (ACAT), the enzyme responsible for the formation of hepatic cholesteryl esters. These results demonstrate that (a) I3C lowers serum cholesterol levels at concentrations that have no discernible effect on hepatic cholesterol homoeostasis, and (b) at higher doses of I3C, hepatic microsomal cholesterol levels are significantly lowered and ACAT activity is significantly elevated. These latter effects are not accompanied by changes in serum cholesterol levels and may represent compensatory mechanisms to restore cholesterol homoeostasis in the body. Mechanisms responsible for the effects of I3C on cholesterol homoeostasis are proposed.

Animals↗
PubMed1994

Surface modification of poly(lactide-co-glycolide) nanospheres by biodegradable poly(lactide)-poly(ethylene glycol) copolymers.

The modification of surface properties of biodegradable poly(lactide-co- glycolide) (PLGA) and model polystyrene nanospheres by poly(lactide)-poly(ethylene glycol) (PLA:PEG) copolymers has been assessed using a range of in vitro characterization methods followed by in vivo studies of the nanospheres biodistribution after intravenous injection into rats. Coating polymers with PLA:PEG ratio of 2:5 and 3:4 (PEG chains of 5000 and 2000 Da. respectively) were studied. The results reveal the formation of a PLA:PEG coating layer on the particle surface resulting in an increase in the surface hydrophilicity and decrease in the surface charge of the nanospheres. The effects of addition of electrolyte and changes in pH on stability of the nanosphere dispersions confirm that uncoated particles are electrostatically stabilized, while in the presence of the copolymers, steric repulsions are responsible for the stability. The PLA:PEG coating also prevented albumin adsorption onto the colloid surface. The evidence that this effect was observed for the PLA:PEG 3:4 coated nanospheres may indicate that a poly(ethylene glycol) chain of 2000 Da can provide an effective repulsive barrier to albumin adsorption. The in vivo results reveal that coating of PLGA nanospheres with PLA:PEG copolymers can alter the biodistribution in comparison to uncoated PLGA nanospheres. Coating of the model polystyrene nanospheres with PLA:PEG copolymers resulted in an initial high circulation level, but after 3 hours the organ deposition data showed values similar to uncoated polystyrene spheres. The difference in the biological behaviour of coated PLGA and polystyrene nanospheres may suggest a different stability of the adsorbed layers on these two systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Polystyrene-poly (ethylene glycol) (PS-PEG2000) particles as model systems for site specific drug delivery. 2. The effect of PEG surface density on the in vitro cell interaction and in vivo biodistribution.

The effect of differing densities of poly (ethylene glycol-2000) (PEG2000) at the particle surface of polystyrene-poly (ethylene glycol-2000) (PS-PEG2000) particles was assessed in terms of hydrophobic interaction chromatography (HIC) and the in vitro and in vivo behaviour of the particles. The particles, with different surface densities of PEG, were prepared by varying the copolymerizing reaction of styrene with a PEG macromonomer. There is a clear relationship between the surface density of PEG as determined by X-ray photoelectron spectroscopy and surface hydrophobicity as assessed by hydrophobic interaction chromatography (HIC). Similarly, the interaction of the particles with non-parenchymal liver cells in in vitro studies was shown to decrease as the surface density of PEG increases. The in vivo study investigating the biodistribution of the PS-PEG particles after intravenous injection into rats reveals that a relationship exists between the surface density of PEG and the extent to which the particles remain in the circulation, avoiding recognition by the reticuloendothelial system. Particles with the higher surface densities show increased circulatory times which compared well with data for particles prepared with the surface adsorbed PEO-PPO block copolymer, Poloxamine 908.

Animals↗
PubMed1994

Causes of admissions of rural African patients to Murchison Hospital, Natal, South Africa.

An analysis has been made of causes of admission of black patients in 1991 to Murchison Hospital, Port Shepstone, Natal. Of 6675 total admissions, 6329 (95%) were classifiable. Of the latter, 1462 (23%) were aged 12 years and-younger, namely, 763 boys and 699 girls. Their chief causes of admission were pneumonia, gastroenteritis, trauma, acute glomerular nephritis, and malnutritional diseases. Of 4867 adults (73%), 1536 were males and 3331 females. Among men, chief causes were tuberculosis, congestive cardiac failure, hypertension and cerebral vascular accidents. Among women, apart from pregnancy, chief causes of admission were disorders of pregnancy, tuberculosis, congestive cardiac failure, pneumonia, diabetes, and hypertension. Of western diseases, 3.9% of adults were admitted for diabetes, and 2.8% for asthma. The general pattern of admissions is similar to that in other rural hospitals. The causes of admissions are discussed, regarding (1) public health improvements occurring, and (2) means of promoting further improvements by (a) community self-help, and (b) help from State health and other services.

Adult↗
PubMed1987

Suddenly, at home.

Explore the source record for details and available documents.

Child, Preschool↗
PubMed1984

Two unusual complications related to fibre-optic endoscopy. Case reports.

Two unusual complications related to fibre-optic endoscopy are described. In one case a pneumomediastinum occurred during gastroscopy with no evidence of perforation. The patient was treated conservatively and made an uneventful recovery. The suggested mechanism is that of alveolar leakage resulting from raised intrathoracic pressure. The other is a case of temporomandibular joint dislocation, a complication not previously described.

Adult↗
PubMedDate not supplied

Insulin-like growth factor-1 inscribes a gene expression profile for angiogenic factors and cancer progression in breast epithelial cells.

Activation of the insulin-like growth factor-1 receptor (IGF-1R) by IGF-1 is associated with the risk and progression of many types of cancer, although despite this it remains unclear how activated IGF-1R contributes to cancer progression. In this study, gene expression changes elicited by IGF-1 were profiled in breast epithelial cells. We noted that many genes are functionally linked to cancer progression and angiogenesis. To validate some of the changes observed, the RNA and/or protein was confirmed for c-fos, cytochrome P450 1A1, cytochrome P450 1B1, interleukin-1 beta, fas ligand, vascular endothelial growth factor, and urokinase plasminogen activator. Nuclear proteins were also temporally monitored to address how gene expression changes were regulated. We found that IGF-1 stimulated the nuclear translocation of phosphorylated AKT, hypoxic-inducible factor-1 alpha, and phosphorylated cAMP-responsive element-binding protein, which correlated with temporal changes in gene expression. Next, the promoter regions of IGF-1-regulated genes were searched in silico. The promoters of genes that clustered together had similar regulatory regions. In summary, IGF-1 inscribes a gene expression profile relevant to cancer progression, and this study provides insight into the mechanism(s) whereby some of these changes occur.

Blotting, Western↗
PubMedDate not supplied

Characterization of canine MDR1 mRNA: its abundance in drug resistant cell lines and in vivo.

BACKGROUND: Overexpression of the MDR1 gene often contributes to antineoplastic drug resistance. The purpose of this study was to characterize the canine MDR1 mRNA homologue and evaluate its expression in both canine cell lines and lymphomas. MATERIALS AND METHODS: The abundance of the canine MDR1 transcript was assessed in three resistant cell lines and in pretreatment canine lymphoma using semi-quantitative RT/PCR. RESULTS: Canine transcript was 4.5 Kb with 93% sequence homology to human MDR1, and 90% homology to mouse and hamster equivalent genes. Increase in MDR1 transcript levels was observed in three progressively resistant canine cell lines. De novo MDR1 transcript expression was independent of response to therapy in dogs with lymphoma. CONCLUSIONS: We conclude that the canine MDR1 mRNA homologue is structurally similar to the human transcript. Expression of MDR1 mRNA correlates with in vitro drug sensitivity but does not correlate with in vivo doxorubicin sensitivity in canine lymphoma.

Adrenal Glands↗