Biomedical subjects

L L Wood

Publications and source records attributed to L L Wood.

6 recordsLinked to original sources

PubMed1991

A collaborative study to establish a U.S. reference for tissue plasminogen activator (t-PA).

In 1987 the Second International Standard for tissue plasminogen activator (t-PA) was established by the World Health Organization following an international collaborative study. At that time, the Center for Biologics Evaluation and Research (CBER) decided to establish a national reference t-PA to be used in lot release potency testing of Alteplase, a licensed t-PA biological or of other t-PAs in development. A candidate recombinant t-PA (rt-PA) preparation was donated by Genentech, Inc. (South San Francisco, California) for this purpose and a collaborative study was launched to calibrate this material against the 2nd I.S. Four laboratories (including the Center for Biologics Evaluation and Research (CBER) and three manufacturers) participated in the study to establish the potency of the rt-PA preparation using a clot lysis assay. The results indicate that the potency of the U.S. reference for t-PA is 2900 international units (IU) per vial.

Humans↗

PubMed1990

Characterization of tissue plasminogen activator binding proteins isolated from endothelial cells and other cell types.

Human tissue plasminogen activator (t-PA) was shown to bind specifically to human osteosarcoma cells (HOS), and human epidermoid carcinoma cells (A-431 cells). Crosslinking studies with DTSSP demonstrated high molecular weight complexes (130,000) between 125I-t-PA and cell membrane protein on human umbilical vein endothelial cells (HUVEC), HOS, and A-431 cells. A 48-65,000 molecular weight complex was demonstrated after crosslinking t-PA peptide (res. 7-20) to cells. Ligand blotting of cell lysates which had been passed over a t-PA affinity column revealed binding of t-PA to 54,000 and 95,000 molecular weight proteins. Several t-PA binding proteins were identified in immunopurified cell lysates, including tubulin beta chain, plasminogen activator inhibitor type 1 and single chain urokinase.

Carrier Proteins↗

PubMed1990

Immobilization of enzymes with polyaziridines.

A novel method of enzyme immobilization using a low molecular weight prepolymer of tri-functional aziridines which can immobilize enzymes both by covalent attachment and entrapment within a gel matrix is described. The enzymes are immobilized on a solid support and exhibit an excellent retention of enzymatic activity. The immobilization procedure is essentially a single step process which can be easily performed at room temperature or 4 degrees C in either aqueous solution or in an inert organic solvent. The polyaziridines used in the immobilization are nontoxic, available in bulk at low cost and completely miscible with water and many organic solvents, thus providing one of the most satisfactory methods of immobilization available.

Biotechnology↗

PubMed1978

A rapidly polymerizing polyurethane for transcatheter embolization.

A polyurethane prepolymer was evaluated as a transcatheter embolizing agent. Low viscosity permits injection through small catheters. Polymerization is initated on contact with blood and completed within 10 seconds. Downstream propagation is better then that of cyanoacrylate and comparable to that of silicone rubber. No systemic toxicity was observed in acute animal experiments. However, dissolution of arterial walls and extravasation out of the vascular bed of chronically embolized organs suggest significant local tissue toxicity and make further evaluation necessary before clinical testing.

Abscess↗

PubMed1978

Bacterial endocarditis with obstruction of the right atrioventricular orifice and the pulmonary outflow trace in an African monkey (Cercopithecus aethiops).

A 7 to 8-year-old male African green monkey (Cercopithecus aethiops) was found moribund in his cage. Fluid and antibiotic therapy were administered, but the monkey dies 2 hours later. At necropsy, large septic mural thrombi obstructed the right atrioventricular orifice and the pulmonary outflow tract, and smaller septic thrombi were attached to the leaflets of the pulmonary and mitral valves. Staphylococci were isolated from the large thrombus occluding the atrioventricular orifice. Large abscesses were present in the upper and lower lobes of the right lung, and small, wedge shaped infarcts were present in the lungs and kidneys. The clinical and pathologic findings were consistent with a rapidly progressive form of bacterial endocarditis. This was the only case of vegetative bacterial endocarditis seen at this instituion in 700 necropsies of nonhuman primates.

Animals↗

PubMed1977

Stimulation of cholesterol esterification in rhesus monkey arterial smooth muscle cells.

The influence of homologous high density lipoprotein (HDL) and low density lipoprotein (LDL) and of whole hypercholesterolemic serum on the esterification of oleic acid and cholesterol was studied in rhesus monkey arterial smooth muscle cells. Whole hypercholesterolemic serum and isolated LDL stimulated cholesterol esterification as much as 10-fold using either cholesterol-1,2-3H or oleate-1-14C as substrate. At the same concentrations of cholesterol, HDL stimulated cholesterol esterification to a lesser extent, to a maximum of 3-fold. Associated with the stimulation of cholesterol esterification by LDL or whole hypercholesterolemic serum was a greater than 10-fold increase in the cholesteryl ester content of the arterial smooth muscle cells. Esterification to cholesterol reached a maximum after 8-12 hours of culture with either hypercholesterolemic serum or LDL. The stimulation of esterification was specific for esterification to cholesterol because there was little change in incorporation of fatty acid into triglycerides and phospholipids. These studies provide further evidence that a major consequence of the interaction of plasma LDL with the cellular elements of the arterial wall is a stimulation of cholesterol esterification. These studies, coupled with the observation that cholesteryl esters, more than any other single component, increase in the atherosclerotic artery, suggest an important role of a stimulation in cholesterol esterification in the pathogenesis of atherosclerosis.

Animals↗