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Biomedical subjects

W Anderson

Publications and source records attributed to W Anderson.

At least 19 recordsLinked to original sources
PubMed1992

Improved detection of antibodies to hepatitis C virus in dialysis patients using a second-generation enzyme immunoassay.

We tested serum samples from 99 patients undergoing maintenance hemodialysis for hepatitis C virus (HCV) antibodies using a first-generation, licensed anti-HCV enzyme immunoassay (EIA) and a second-generation anti-HCV EIA that detect three gene products c100-3, NS3, and core. Specimens that were repeatedly reactive by either or both screening assays were further evaluated by testing with supplemental EIAs and a dot blot immunoassay. There was 87.9% agreement between the licensed HCV EIA and the HCV EIA second generation. HCV EIA Second Generation detected 10 more positive specimens than HCV EIA, for an increase in detection from 33.3% (33/99) to 43.4% (43/99). We conclude that HCV EIA Second Generation improves detection of HCV infection in hemodialysis patients.

Adult↗
PubMed1992

Diagnostic value of pleural fluid cytology in occult Boerhaave's syndrome.

When Boerhaave's syndrome presents with atypical clinical features and eludes prompt diagnosis, delays in surgical therapy increase complications and mortality. We present a patient with occult Boerhaave's syndrome who had nondiagnostic esophageal contrast studies and thoracic computed tomography. Pleural fluid cytologic analysis established the presence of esophageal rupture by detecting undigested food particles.

Esophageal Diseases↗
PubMed1991

Brain, blood, and cerebrospinal fluid distribution of a zidovudine chemical delivery system in rabbits.

Improved brain delivery of zidovudine (AZT) was shown to occur after iv dosing of a chemical delivery system (CDS) for the modified deoxynucleoside. Specifically, administration of a 25-mg/kg dose of 5'-[(1-methyl-1,4-dihydropyridin-3-yl)carbonyl]-3'-azido-3'-deoxyt hymidine (AZT-CDS) generated higher and more sustained levels of AZT in brain tissue of rabbits than did dosing with AZT itself. The significant increase in the area under the AZT brain concentration-time curve occurred with lower AZT present in the systemic circulation and with similar AZT levels in cerebrospinal fluid. These results, as well as previously published reports examining AZT-CDS in mice, rats, and dogs, indicate that this delivery system may be beneficial in the treatment of AIDS-related encephalopathy.

Animals↗
PubMed1979

The response of bone apposition rate to some nonphysiologic conditions.

The response of bone apposition to some nonphysiologic conditions was investigated. In rabbits, the normal osteogenic rhythm was totally abolished shortly following treatment of hydrocortisone at a dose of 2 mg/kg body weight daily. A new rhythm developed after the treatment was continued for 20 1/2--34 days. The rate of bone apposition was significantly depressed compared to normal data reported previously. In rats receiving one U.S.P. unit of parathyroid extract daily for 14 days, the rate of bone apposition was significantly higher than that in control rats. In both sepcies, the response to an exogenous hormone was identified for all skeletal locations. It was concluded that new bone apposition was a function of activated osteoblasts, and that this function responded only to general body control mechanisms.

Animals↗
PubMed1979

Energy-conformation studies of frequency of beta-turns in tetrapeptide sequences.

The optimized energies of seven beta-bends, repeating C5 and C7, and right- and left-handed alpha-helical conformations for each of eight tetrapeptides have been computed using empirical methods. Eight tetramers were selected: four helix-forming sequences with hydrophobic residues such as Val, Leu, Ile and Trp, and four helix-breaking sequences with hydrophilic residues such as Asp, Asn and Ser, as determined by their frequency of occurrence in beta turns in proteins. Analysis of the optimized conformations with energies less than or equal to 2.1 kcal/mol from the absolute minimum energy conformer for each tetramer reveals a correlation between low-energy conformations and those predicted from observed protein structures. These results show that energy calculations on small peptide fragments may be usefulin predicting protein structure.

Amino Acid Sequence↗
PubMed1978

Activation of adenylate cyclase in cultured fibroblasts by trypsin.

Adenylate cyclase activity measured in membranes of cultured normal rat kidney (NRK) fibroblasts was markedly increased by prior treatment of the intact cells with trypsin. Cell population density influenced the extent of activation observed. Trypsin treatment of sparse cells significantly enhanced adenylate cyclase activity, whereas similar treatment of confluent cells caused only a slight increase in adenylate cyclase activity. The degree of activation noted after trypsin treatment also varied depending on the adenylate cyclase function measured. Activity determined in the presence of GTP alone showed the greatest increase after trypsin treatment. Similar enhancement of adenylate cyclase activity of a washed cell membrane preparation was achieved by the addition of low concentrations of trypsin directly to the adenylate cyclase reaction mixture. The membranes of confluent NRK fibroblasts initially exhibited higher adenylate cyclase activity than did membranes of sparse cells. The present results suggest that this change in adenylate cyclase activity at cell confluence is not due to an increase in the amount of adenylate cyclase in the cell membrane but rather to a change in membrane components that regulate its activity. Proteolytic activation of adenylate cyclase appears to result from degradation of cell membrane proteins that modulate the activity of this enzyme.

Adenylyl Cyclases↗