Search PubMed⌕ Search

Biomedical subjects

D L Martin

Publications and source records attributed to D L Martin.

At least 145 records · Page 8Linked to original sources
PubMed1983

Persistence of cholera in the United States.

In 1973, 1978, and 1981, cases of cholera were acquired along the Gulf Coast of the United States. The isolates from all of the cases were toxigenic Vibrio cholerae O-group 1, biotype El Tor, serotype Inaba, hemolytic, and of the same phage sensitivity pattern, and all had the same restriction endonuclease pattern by molecular genetic analysis. The strain from one of the two 1981 cases differed from the others in having a small plasmid and a negative Voges-Proskauer reaction. Multiple importations, chronic carriers, and continuous occurrence of undetected cases are unlikely explanations for these findings, which suggest that toxigenic V. cholerae 01 can multiply and persist for years in some environments, making eradication of cholera a formidable task.

Adult↗
PubMed1980

Tetracycline-labeled human bone from ancient Sudanese Nubia (A.D. 350).

Nubian bone recovered from an X-group cemetery (A.D. 350 to 550) exhibits a pattern of fluorescence identical to that of modern tetracycline-labeled bone. When it is viewed under ultraviolet light at 490 angstroms, fluorophors are visible as a characteristic yellow-green fluorescence on surfaces that were actively mineralizing at the time of exposure. Contamination of stored grains provided the proper environment for cultivation of tetracycline-producing Streptomycetes. Evidence for exposure to antibiotics in an archeological population is relevant to studies of the evolution of R factors and to the interpretation of health and disease within the population.

Bone and Bones↗
PubMed1980

Interaction of chemotactic factors with human polymorphonuclear leukocytes: studies using a membrane potential-sensitive cyanine dye.

Changes in the fluorescence intensity of the dye 3-3' dipentyloxacarbocyanine were measured in suspensions of purified human peripheral blood polymorphonuclear leukocytes (PMNs) during exposure to the chemotactic factors N-formyl-methionyl-leucyl-phenylalanine (f-met-leu-phe) and partially purified C5a. Incubation of PMNs with dye resulted in a stable fluorescence reflecting the resting membrane potential of the cell. Exposure of PMNs to dye did not affect stimulated chemotaxis or secretion. The mechanism of cell-associated dye fluorescence involved solvent effects from partitioning of the eye between the aqueous incubation medium and the cell and not dye aggregation, Chemotactically active concentrations of f-met-leu-phe (5 x 10(-9) M or greater) produced a biphasic response characterized as a decrease followed by an increase in fluorescence. No fluorescence response was seen in lysed PMNs, and no response was elicited by an inhibitor of f-met-leu-phe binding (carbobenzoxy-phenylalanyl-methionine). The ability of several other synthetic peptides to elicit a fluorescence response corresponded to their effectiveness as chemotactic agents. Although the first component of the response suggested a depolarization, it was not influenced by variation in the external concentration of sodium, potassium, chloride, or calcium, and could not be characterized as a membrane potential change. The second component of the response, which was inhibited by both Mg2+ (10 mM)-EGTA (10 mM) and high external potassium, was compatible with a membrane hyperpolarization. The data indicate that chemotactic factors produce changes in dye fluorescence which can, at least in part, be attributed to a hyperpolarizing membrane potential change occurring across the plasma membrane.

Albumins↗