PubMed Health⌕ Search

Biomedical subjects

B McKinney

Publications and source records attributed to B McKinney.

At least 19 recordsLinked to original sources
PubMed2002

Environmental contaminants in prey and tissues of the peregrine falcon in the Big Bend Region, Texas, USA.

Peregrine falcons (Falco peregrinus) have been recorded nesting in Big Bend National Park, Texas, USA and other areas of the Chihuahuan Desert since the early 1900s. From 1993 to 1996, peregrine falcon productivity rates were very low and coincided with periods of low rainfall. However, low productivity also was suspected to be caused by environmental contaminants. To evaluate potential impacts of contaminants on peregrine falcon populations, likely avian and bat prey species were collected during 1994 and 1997 breeding seasons in selected regions of western Texas, primarily in Big Bend National Park. Tissues of three peregrine falcons found injured or dead and feathers of one live fledgling also were analyzed. Overall, mean concentrations of DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene], a metabolite of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane], were low in all prey species except for northern rough-winged swallows (Stelgidopteryx serripennis, mean = 5.1 microg/g ww). Concentrations of mercury and selenium were elevated in some species, up to 2.5 microg/g dw, and 15 microg/g dw, respectively, which upon consumption could seriously affect reproduction of top predators. DDE levels near 5 microg/g ww were detected in carcass of one peregrine falcon found dead but the cause of death was unknown. Mercury, selenium, and DDE to some extent, may be contributing to low reproductive rates of peregrine falcons in the Big Bend region.

Animals↗
PubMed1996

The 2.8 A structure of a T = 4 animal virus and its implications for membrane translocation of RNA.

Simple RNA animal viruses generally enter cells through receptor-mediated endocytosis followed by acid pH dependent release and translocation of RNA across the endosomal membrane. The T = 3 nodaviruses contain prefabricated pentameric helical bundles that are cleaved from the remainder of the subunits by an assembly-dependent auto-proteolysis and they are positioned for release through 5-fold axes of the particle. We previously proposed that these bundles may serve as conduits for RNA membrane translocation. Additional support for this hypothesis is now provided by the first atomic resolution structure of a T = 4 RNA virus, where we find cleavage sites and helical bundles nearly identical with those observed in T = 3 nodaviruses. The helices are of sufficient length to span a membrane bilayer and the internal diameter of the coiled bundle could accommodate ssRNA. The T = 4 particle has a mean outer diameter of 410 A and is formed by 240 copies of a single subunit type. The subunit is composed of a helical inner domain (where the cleavage occurs) containing residues preceding and following a canonical, viral, eight-stranded beta-sandwich that forms the contiguous shell. Inserted between two strands of the shell domain are 133 residues with an immunoglobulin c-type fold. The initial gene product consists of 644 amino acid residues and is cleaved between residues Asn570 and Phe571 in the mature particle determined in this analysis.

Biological Transport↗
PubMed1996

Surprised by tears.

Explore the source record for details and available documents.

Adaptation, Psychological↗
PubMed1995

Under new management: asthma and the elderly.

1. Since asthma may not develop until middle age and may then be accompanied or camouflaged by other complications, it often goes unrecognized in the elderly. 2. The inflammatory disease process can be both acute and chronic, and falls under six different categories. 3. The role of the nurse educator is to teach the elderly asthmatic self-care skills.

Aged↗
PubMed1994

Comparative studies of T = 3 and T = 4 icosahedral RNA insect viruses.

Crystallographic and molecular biological studies of T = 3 nodaviruses (180 identical subunits in the particle) and T = 4 tetraviruses (240 identical subunits in the particle) have revealed similarity in both the architecture of the particles and the strategy for maturation. The comparative studies provide a novel opportunity to examine an apparent evolution of particle size, from smaller (T = 3) to larger (T = 4), with both particles based on similar subunits. The BBV and FHV nodavirus structures are refined at 2.8 A and 3 A respectively, while the N omega V structure is at 6 A resolution. Nevertheless, the detailed comparisons of the noda and tetravirus X-ray electron density maps show that the same type of switching in subunit twofold contacts is used in the T = 3 and T = 4 capsids, although differences must exist between quasi and icosahedral threefold contacts in the T = 4 particle that have not yet been detected. The analyses of primary and tertiary structures of noda and tetraviruses show that N omega V subunits undergo a post assembly cleavage like that observed in nodaviruses and that the cleaved 76 C-terminal residues remain associated with the particle.

Crystallography, X-Ray↗
PubMed1976

Endocardial changes produced in Patus monkeys by the ablation of cardiac lymphatics and the administration of a plantain diet.

The effect of obliteration of the cardiac lymph drainage and prolonged feeding with a plantain diet in Patus monkeys was studied. Althout obliteration of the cardiac lymph supply produced fibroelastotic lesions the addition of a plantain diet did not usually produce much increase in cardiac fibrosis and the changes of EMF or CUO were not seen. The reasons for this are discussed.

Animals↗
PubMed1975

Studies on the experimental production of endomyocardial fibrosis and cardiomegaly of unknown origin by dietary means.

Three groups of rats were kept on diets similar to those eaten by indigenous inhabitants in parts of Africa where CUO and EMF are commonly found, for 30 months. Many of the animals on a tryptophan-deficient diet developed CUO whereas those on a tryptophan-deficient diet which contained a 5-HT content also developed lesions similar to EMF. The third group of rats, which ate a diet similar to this second group but supplemented by a high-protein intake, did not develop any cardiac lesions.

5,6-Dihydroxytryptamine↗