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L Dowling

Publications and source records attributed to L Dowling.

8 recordsLinked to original sources
PubMed1998

Leukocystatin, a new Class II cystatin expressed selectively by hematopoietic cells.

We describe a new cystatin in both mice and humans, which we termed leukocystatin. This protein has all the features of a Class II secreted inhibitory cystatin but contains lysine residues in the normally hydrophobic binding regions. As determined by cDNA library Southern blots, this cystatin is expressed selectively in hematopoietic cells, although fine details of the distribution among these cell types differ between the human and mouse mRNAs. In addition, we have determined the genomic organization of mouse leukocystatin, and we found that in contrast to most cystatins, the leukocystatin gene contains three introns. The recombinant proteins corresponding to these cystatins were expressed in Escherichia coli as N-terminal glutathione S-transferase or FLAGTM fusions, and studies showed that they inhibited papain and cathepsin L but with affinities lower than other cystatins. The unique features of leukocystatin suggests that this cystatin plays a role in immune regulation through inhibition of a unique target in the hematopoietic system.

Amino Acid Sequence↗
PubMedDate not supplied

Age-related changes in a spontaneously reassociating fraction of mouse DNA.

Rapidly reassociating fractions have been isolated from mouse brain and liver nuclear DNA by hydroxyapatite fractionation of sonicated and denatured preparations incubated at a Cot of 1. When prepared by thermal denaturation, a subfraction of this DNA, representing approximately 0.6% of liver and brain DNA, has been shown to spontaneously reassociate at Cot 10(-5). This fraction increases 3-fold in DNA from old animals. When prepared by alkaline denaturation or treated with pronase, no age-related increase is observed, suggesting the presence of an alkali-labile stabilizing protein component in DNA from old cells. A portion of this fraction is observed by electron microscopy under denaturing conditions to consists of looped hairpin structures in DNA from old, but not from yound or mature animals. These structures are not seen after pronase treatment.

Aging↗
PubMedDate not supplied

Assessment of body fat and lean in the elderly by measuring body carbon and oxygen: validation against hydrodensitometry.

Based on the observation that the carbon-to-oxygen ratio (C/O) in tissue is a measure of fat content, we developed a model which correlates C/O to percent body fat. Carbon and oxygen mass and their ratio are measured in vivo by fast neutron inelastic scattering, using a miniature D-T neutron generator, at a radiation exposure of less than 0.06 mSv. We tested the validity of this model against hydrodensitometry with 19 healthy adult volunteers. The method was found to be accurate and insensitive to assumptions about the composition of lean tissue and, therefore, appropriate for studying the elderly and patients with catabolic conditions.

Adipose Tissue↗