PubMed Health⌕ Search

Biomedical subjects

M Foley

Publications and source records attributed to M Foley.

34 records · Page 2Linked to original sources
PubMed1987

Biophysical properties of the surface lipid of parasitic nematodes.

The biophysical properties of the surface lipid layer (the epicuticle) of living parasitic nematodes (Trichinella spiralis and Toxocara canis) were examined using fluorescent lipid analogues. A variety of such probes were screened, and only 5-N-(octadecanoyl)-aminofluorescein was found to insert into the outer lipid layer. Fluorescence quenching experiments showed that this probe was confined to the surface, and the rate of its lateral diffusion was then measured by Fluorescence Recovery After Photobleaching. This showed that the probe was not free to diffuse within the plane of the epicuticle. This structure is, therefore, extraordinary in its selectivity to lipid probes, and in the restricted lateral mobility of inserted lipid components.

Animals↗
PubMed1987

Granulocytopenia complicating colchicine therapy for primary biliary cirrhosis.

A case is presented of a 76-yr-old woman with primary biliary cirrhosis and adult polycystic liver disease who developed bone marrow toxicity associated with chronic low-dose colchicine therapy. Two months after starting colchicine therapy (0.6 mg b.i.d. p.o.), the patient developed hematologic toxicity as evidenced by transient but profound granulocytopenia which promptly reversed 4 days after the drug was stopped. Bone marrow examination revealed moderate hypocellularity of all cell lines and striking dysplastic changes in the late myeloid and erythroid series. There was no apparent toxicity involving other organ systems. The patient fully recovered. This case is compared with previous descriptions of colchicine toxicity.

Aged↗
PubMed1986

The lateral diffusion of lipid probes in the surface membrane of Schistosoma mansoni.

The technique of fluorescence recovery after photobleaching was used to measure the lateral diffusion of fluorescent lipid analogues in the surface membrane of Schistosoma mansoni. Our data reveal that although some lipids could diffuse freely others exhibited restricted lateral diffusion. Quenching of lipid fluorescence by a non-permeant quencher, trypan blue, showed that there was an asymmetric distribution of lipids across the double bilayer of mature parasites. Those lipids that diffused freely were found to reside mainly in the external monolayer of the outer membrane whereas lipids with restricted lateral diffusion were located mainly in one or more of the monolayers beneath the external monolayer. Formation of surface membrane blebs allowed us to measure the lateral diffusion of lipids in the membrane without the influence of underlying cytoskeletal structures. The restricted diffusion found on the normal surface membrane of mature parasites was found to be released in membrane blebs. Quenching of fluorescent lipids on blebs indicated that all probes were present almost entirely in the external monolayer. Juvenile worms exhibited lower lateral diffusion coefficients than mature parasites: in addition, the lipids partitioned into the external monolayer. The results are discussed in terms of membrane organization, cytoskeletal contacts, and biological significance.

Animals↗
PubMed1986

Lateral diffusion of proteins in the periplasm of Escherichia coli.

We have introduced biologically active, fluorescently labeled maltose-binding protein into the periplasmic space of Escherichia coli and measured its lateral diffusion coefficient by the fluorescence photobleaching recovery method. Diffusion of this protein in the periplasm was found to be surprisingly low (lateral diffusion coefficient, 0.9 X 10(-10) cm2 s-1), about 1,000-fold lower than would be expected for diffusion in aqueous medium and almost 100-fold lower than for an equivalent-size protein in the cytoplasm. Galactose-binding protein, myoglobin, and cytochrome c were also introduced into the periplasm and had diffusion coefficients identical to that determined for the maltose-binding protein. For all proteins nearly 100% recovery of fluorescence was obtained after photobleaching, indicating that the periplasm is a single contiguous compartment surrounding the cell. These data have considerable implications for periplasmic structure and for the role of periplasmic proteins in transport and chemotaxis.

ATP-Binding Cassette Transporters↗
PubMedDate not supplied

Neural tissue uptake and clearance of iohexol following lumbar myelography in rabbits.

The diffusion of water-soluble contrast media (CM) into the extracellular space of the central nervous system following injection into the subarachnoid space has previously been shown. As a result of this, water-soluble CM will come in direct contact with the neurons and may interfere with their normal function. The toxic effects would thus be a result both of the molecular properties of the CM as well as the local tissue concentration. The neuronal tissue uptake and clearance of metrizamide in rabbits following lumbar myelography was described in a previous study by our group. This study indicated some retention of metrizamide in the spinal cord probably as a result of binding of the CM to the cell membrane. The mechanism for this has not yet been shown although it may relate to the binding of metrizamide via its 2-deoxy-D-glucose (2-DG) portion and the specific glucose membrane carrier. The present investigation was performed to evaluate the diffusion kinetics of a new non-ionic CM. With iohexol, which lacks a 2-DG component in its molecule a direct relationship between the neural tissue and CSF concentration was found which seems to follow a simple diffusion model. Since iohexol shows no sign of entrapment in the tissue, the contact time for neurons will be shorter than that seen with metrizamide assuming that their rate of drainage from the CSF is identical.

Animals↗
PubMedDate not supplied

CNA testifies on AIDS.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗