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Biomedical subjects

A Dong

Publications and source records attributed to A Dong.

5 recordsLinked to original sources
PubMed1992

Secondary structure of the pentraxin female protein in water determined by infrared spectroscopy: effects of calcium and phosphorylcholine.

The secondary structure of hamster female protein in aqueous solutions in the presence or absence of calcium and phosphorylcholine has been investigated using Fourier transform infrared spectroscopy. Our present studies provide the first evaluation of the secondary structure of FP and its calcium- and phosphorylcholine-dependent conformational changes. Quantitative analysis indicated that FP is composed of 50% beta-sheet, 11% alpha-helix, 29% beta-turn, and 10% random structures. Calcium- and phosphorylcholine-dependent infrared spectral changes were observed in regions assigned to beta-sheet, alpha-helix, turn, and random structures. The infrared-based secondary structure compositions were used as constraints to compute theoretical locations for the different secondary structures along the amino acid sequence of the FP protein. Two putative calcium-binding sites were proposed for FP (residues 93-109 and 150-168) as well as other members of the pentraxin family on the basis of the theoretical secondary structure predictions and the similarity in sequence between the pentraxins and EF-hand calcium-binding proteins. The changes in protein conformation detected upon binding of calcium and phosphorylcholine provide a mechanism for the effects of these ligands on physiologically important properties of the protein, e.g., activation of complement and association with amyloids.

Alpha-Globulins↗
PubMed1992

Computer-assisted neurosurgery: simulation and automation.

Instrumentation has been developed to automate, accurately guide, and integrate microsurgery laser resection equipment that is used in stereotactic brain surgery. The instrument is a computer-controlled laser-guiding system. The improvement in the accuracy comes from relying on a certain well-referenced three-dimensional surgical orientation, and computer-preplanned tumor contours, rather than only the surgeons hand-eye orientation in the operating room.

Automation↗
PubMed1991

Secondary structure analysis of the scrapie-associated protein PrP 27-30 in water by infrared spectroscopy.

A protease-resistant form of the protein PrP (PrP-res) accumulates in tissues of mammals infected with scrapie, Creutzfeldt-Jakob disease, and related transmissible neurodegenerative diseases. This abnormal form of PrP can aggregate into insoluble amyloid-like fibrils and plaques and has been identified as the major component of brain fractions enriched for scrapie infectivity. Using a recently developed technique in Fourier transform infrared spectroscopy which allows protein conformational analysis in aqueous media, we have studied the secondary structure of the proteinase K resistant core of PrP-res (PrP-res 27-30) as it exists in highly infectious fibril preparations. Second-derivative analysis of the infrared spectra has enabled us to quantitate the relative amounts of different secondary structures in the PrP-res aggregates. The analysis indicated that PrP-res 27-30 is predominantly composed of beta-sheet (47%), which is consistent with its amyloid-like properties. In addition, significant amounts of turn (31%) and alpha-helix (17%) were identified, indicating that amyloid-like fibrils need not be exclusively beta-sheet. The infrared-based secondary structure compositions were then used as constraints to improve the theoretical localization of the secondary structures within PrP-res 27-30.

Acetylglucosamine↗
PubMed1976

Feasibility of routine testing for hepatitis B surface antigen in hospital employees and restriction of carriers.

In 1972-73, 48 hospital staff members were tested selectively for hepatitis B surface antigen (HBsAg); 4 (8.3%) were found to be HBsAg-positive. In 1974-75, 1415 staff members were tested routinely before employment and at periodic health examination; 25 (1.8%) were found to be HBsAg-positive. Of the HBsAg-positive staff members 55.2% were Asians, this proportion being significantly (P less than 0.05) greater than that of any other ethnic group, and 31.0% were southern Europeans. Nurses and laboratory technologists were the largest professional groups among the HBsAg-positive staff, each accounting for 20.7%. Our results indicate that it is impractical to carry out routine testing of hospital staff for HBsAg. Selective testing and restriction from work in their units is proposed for staff of the renal and peritoneal dialysis units, the emergency department and the intravenous team and dietary staff who handle food directly.

Adult↗