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Biomedical subjects

D L Reed

Publications and source records attributed to D L Reed.

15 recordsLinked to original sources
PubMed2002

Phylogenetic analysis of bacterial communities associated with ectoparasitic chewing lice of pocket gophers: a culture-independent approach.

This study identifies the bacteria associated with ectoparasitic chewing lice that live in the fur of pocket gophers. Samples of chewing lice were collected from pocket gopher hosts in Florida, Missouri, New Mexico, and Costa Rica. We used a molecular sampling method whereby total community DNA was extracted from samples of chewing lice, and PCR was used to selectively amplify small-subunit rRNA genes from bacteria. This culture-independent method yielded ca. 35 distinct lineages representing eight widely divergent groups within the domain Bacteria. Phylogenetic analysis of two lineages (Acinetobacter and Staphylococcus) provides evidence that multiple species of each group are found in chewing lice. Phylogenetic analysis also demonstrated that diversification within chewing lice may be evident in both Acinetobacter and Staphylococcus. Some clones amplified from chewing louse hosts appeared to be distinct from known species of Acinetobacter and Staphylococcus. This diversification may be the result of the extreme isolation of populations of both chewing lice and their pocket gopher hosts.

Animals↗
PubMed2001

Molecular systematics of Selene (Perciformes: Carangidae) based on cytochrome B sequences.

The marine fishes of the genus Selene are morphologically unique, although little is known about how these species are related to other members of the family Carangidae (Perciformes). In addition, questions remain about the potential validity of two putative species and how species groups with unique body forms within Selene are related. We used DNA sequences of the mitochondrial cytochrome b gene to reconstruct the phylogeny of the seven species of Selene along with five additional species of carangids. Maximum-likelihood and maximum-parsimony analyses were used to examine the sequence data and both phylogenetic methods were compared. Maximum-likelihood produced a monophyletic Selene, whereas parsimony analyses did not. Both maximum-likelihood and maximum-parsimony produced similar support for species groups within Selene. Maximum-likelihood produced two monophyletic subgroups within the genus Selene, the "long-finned" and "short-finned" Selene. Maximum-parsimony produced the same monophyletic "long-finned" group but a paraphyletic "short-finned" group. Both analyses confirm that S. brownii and S. setapinnis are distinct species, expunging the question of conspecificity. The phylogenetic placement of the most basal taxon within Selene, S. orstedii, was problematic and differed among analyses. More data are needed to resolve with confidence its correct phylogenetic placement and, thus, the monophyly of the genus Selene.

Animals↗
PubMed2000

The application of standard methods for the determination of toxaphene in environmental media.

In the United States, it is necessary to analyze for toxaphene using approved, validated methods acceptable to the regulatory agencies. As a result of an interlaboratory study and technical exchanges among the US EPA Region IV (EPA), the State of Georgia Environmental Protection Division (EPD), and Hercules Incorporated, guidelines for the application of SW-846 Method 8080 were developed. Results of analyses for sludge, soil, and water samples agreed within a percent relative standard deviation (% RSD) range of 6.9-20%. Through continued technical interchanges, guidance for the application of SW-846 Method 8081 has been developed. The results of analyses of fourteen split samples of soil and sediment produced a percent relative standard deviation that ranged from 1.6% to 127%, with an average of 38%. When two unusually divergent results were removed from consideration, the average % RSD reduced to 26%. The results of analyses of split samples show agreement between the EPA laboratory and a Hercules contract laboratory. Therefore, the guidance has achieved its purpose of producing agreement among data from different laboratories so that data reviewers may have assurance that the analytical method has been applied correctly and consistently for the determination of toxaphene in environmental samples.

Chromatography, Gas↗
PubMed2000

Spatial partitioning of host habitat by chewing lice of the genera Geomydoecus and Thomomydoecus (Phthiraptera: Trichodectidae).

Chewing lice, Geomydoecus and Thomomydoecus, coexist on pocket gophers, Thomomys spp. We investigated the spatial distribution of the 2 genera on their hosts and explored possible mechanisms of resource partitioning by chewing lice. Chewing lice appear to partition available host resources spatially, with Geomydoecus occurring primarily on the lateral and dorsal regions of the host, and Thomomydoecus occurring primarily on the lateral and ventral regions. Although spatial partitioning of the host habitat is evident, it does not appear to be explained by hair diameter. Spatial partitioning of the host's body could be the result of some other factor, possibly temperature or humidity gradients of the host's body.

Animals↗
PubMed1993

Gender differences in AIDS-relevant condom attitudes and condom use.

Two studies, conducted approximately one year apart, examined gender differences in AIDS-relevant condom attitudes, condom use behaviors, and relationships among attitudes and condom use behaviors. Subjects (N = 248, N = 528) were undergraduates, primarily heterosexual. Females reported more favorable attitudes, with the exception of greater inhibition about buying and possessing condoms. Men engaged in preliminary condom use behaviors (carrying and keeping condoms at home) substantially more often than did women. Preliminary condom use behaviors predicted past and intended condom use more consistently for men than for women. Relationships between condom attitudes and condom use behaviors were generally similar for both sexes, with poorer self-control explaining the most variance in past and intended condom use. These results, interpreted from the perspective of Eagly's (1987) gender role theory, suggest that although females may indirectly influence condom use decisions, providing condoms is the expected role of males, infusing them with greater control over the interpersonal process.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Antibodies reactive with human immunodeficiency virus gag-coded antigens (gag reactive only) are a major cause of enzyme-linked immunosorbent assay reactivity in a blood donor population.

Normal blood donors were examined for human immunodeficiency virus (HIV)-reactive antibodies with both virus- and Escherichia coli-expressed env- and gag-coded antigens. The frequency of samples from normal (low-risk) donors that were repeatedly reactive with an HIV enzyme-linked immunosorbent assay blood screening test (Du Pont Co.) was 0.6%. Two classes of HIV serological reactivity were identified: a minor env-reactive class (0.03 to 0.06% of donors) and the predominant env-nonreactive gag-reactive class (gag reactive only [GRO]) (0.4 to 0.5% of donors). Assignment of env reactivity was made by a synthetic (recombinant) env enzyme-linked immunosorbent assay and virus immunoblot. Most GRO sera reacted with p15/p17 bands on HIV immunoblot. Antibody specificity in GRO sera was confirmed by competition-binding studies with viral gag and E. coli-expressed p55gag. This study provides independent verification that gag-specific antibodies are present in many env-nonreactive sera. More serological and virological studies of individuals with this antibody pattern should be pursued to determine the origin of these gag-reactive antibodies.

Antibodies, Viral↗
PubMed1987

Three high molecular weight protease inhibitors of rat plasma. Reactions with trypsin.

We have compared the reactions of trypsin with human alpha 2-macroglobulin (alpha 2M), and three rat plasma protease inhibitors, alpha 1-macroglobulin (alpha 1M), alpha 1-inhibitor III (alpha 1I3), and alpha 2M. All four of these proteins appear to contain reactive thiol esters. The electrophoretic mobility in agarose gels of human and rat alpha 2M is increased by 1 mol of trypsin, while the mobility of alpha 1M and alpha 1I3 is decreased. Treatment with methylamine causes similar mobility changes, except in the case of rat alpha 2M. Titration of human and rat macroglobulins by repeated small additions of trypsin and by assay of liberated SH groups or enhanced ligand fluorescence revealed a stoichiometry of about 1 mol of trypsin/mol of inhibitor. In contrast, addition of macroglobulin to a fixed amount of trypsin and detection of residual amidase or protease activity revealed a stoichiometry of about 2 mol of trypsin for 1 mol of human alpha 2M, about 1.4 mol for rat alpha 1M, and about 1 mol for rat alpha 2M. One mol of trypsin reacted with 2 or more mol of alpha 1I3 by the criteria of SH groups liberated or protease inhibition. Methylamine-treated rat alpha 2M binds a significant amount of trypsin releasing about 2 mol of SH. Radioactive beta-trypsin was covalently bound to subunits of the purified plasma inhibitors. The Mr of the labeled products with rat and human alpha 2M had molecular weights which suggested trypsin was bound to intact as well as cleaved subunit chains and also to multiple chains via cross-linking. Rat alpha 1M also produced a product which may be an intact subunit alpha chain plus trypsin. Greater than 80% of the trypsin was bound covalently to these inhibitors at low molar ratios.

Acute-Phase Proteins↗
PubMed1987

Three high molecular weight protease inhibitors of rat plasma. Isolation, characterization, and acute phase changes.

Rat blood plasma contains three high molecular weight thiol ester-containing proteinase inhibitors, alpha 1-macroglobulin (alpha 1M), alpha 1-inhibitor III (alpha 1I3), and alpha 2-macroglobulin (alpha 2M). Rat serums have been analyzed using a two-dimensional gel electrophoretic technique which optimizes recovery of high molecular weight proteins. alpha 1M, and (alpha beta)4-tetramer in native solution, separated in the second sodium dodecyl sulfate-containing electrophoretic dimension as a disulfide-linked (alpha beta)2-dimer with an approximate Mr of 360 kDa. alpha 1I3 separated in the gels as a single 190-kDa polypeptide. It is also a monomer in native solution by ultracentrifugation criteria. Native rat alpha 2M is a tetramer, but it separates in the gels as a disulfide-linked dimer with an Mr of approximately 360 kDa. The kinetics of changes in concentration of these proteins during the induction of polyarthritis was also measured by quantitative immunoelectrophoresis. In rats with adjuvant-induced polyarthritis, the concentration of alpha 1I3 dramatically decreases and alpha 2M appears and continues to increase in a biphasic manner for 2 weeks. The alpha 1M concentration remains relatively constant. All three macroglobulins were purified utilizing modern rapid chromatographic techniques, and parallel comparisons of their native physicochemical properties were carried out. The N-terminal sequence of the alpha-chain of rat alpha 1M was also shown to share sequence homology with that of alpha 2M. In agreement, Esnard et al. (Esnard, F., Gutman, N., El Moujahed, A., and Gauthier, F. (1985) FEBS Lett. 182, 125-129) recently reported that alpha 1I3 also contains a thiol ester bond, as do alpha 1M and alpha 2M, since it reacts covalently with [14C]methylamine and is cleaved autolytically at 80 degrees C. We have examined negatively stained preparations of native, trypsin-treated, and methylamine-treated human alpha 2M, rat alpha 2M, and rat alpha 1M in the electron microscope. Trypsin appears to convert globular ring-shaped native molecules to rectangular box-like structures, in agreement with the conclusions of a recent report on human alpha 2M (Tapon-Bretaudiere, J., Bros, A., Couture-Tosi, E., and Delain, E. (1985) EMBO J. 4, 85-89).

Acute-Phase Proteins↗
PubMed1987

Anti-GP 120 antibodies from HIV seropositive individuals mediate broadly reactive anti-HIV ADCC.

Cytophilic antibodies which mediate antibody dependent cellular cytotoxicity (ADCC) against envelope antigens of human immunodeficiency virus (HIV) can be found in seropositive individuals. In these experiments, sera from a wide spectrum of HIV infected patients ranging from asymptomatic to overt acquired immunodeficiency syndrome (AIDS) were shown to contain high titers of antibodies that mediate ADCC. Not only did patient antibodies bind to surface expressed viral antigens and mediate ADCC against cells chronically infected with human T-lymphotropic virus type IIIB (HTLV-IIIB), but also against cells infected with the divergent HTLV-IIIRF2 and HTLV-IIIMN viral isolates. Similar results were obtained with target cells bearing purified GP 120 from HTLV-IIIB and HTLV-IIIRF2, indicating that a major portion of the activity was mediated by anti-GP 120 antibodies. Consistent with this was the ability to absorb most of the group-specific ADCC activity from the serum of an HIV infected individual using affinity columns bearing purified HTLV-IIIB GP 120. The finding that human antibodies reactive against the HIV envelope glycoprotein mediate ADCC against cells chronically infected with divergent strains of HIV will have important implications in designing rational approaches to passive and active immunotherapy.

Acquired Immunodeficiency Syndrome↗
PubMed1977

Residues in broiler chickens fed low levels of hexachlorobenzene.

Male broiler chicks (Hubbard-Hubbard) were fed graded levels (0, 0.0006, 0.006, 0.03, and 0.120 p.p.m.) of hexachlorobenzene (HCB) for 8 weeks. Gel permeation chromatography was used to prepare tissue samples from fat, heart, gizzard, leg muscle, breast muscle, kidney, and liver for analysis by gas-liquid chromatography employing electron capture detection. No treatment related trends could be determined for body or organ weights. Histopathologic examination of brain, liver, testes, pancreas, small intestine, ventriculus, spleen, kidney, lung, and heart failed to reveal lesions in either control or treated groups. A linear relationship was found between HCB accumulation in tissues and the dietary HCB level. HCB accumulation was greatest in adipose tissue followed by the heart, gizzard, leg, kidney, liver, and breast. The biomagnification of HCB in adipose tissue of broiler chickens was 11 to 18 times the concentration in the diet. For example, a concentration of 0.03 p.p.m. of HCB in the diet resulted in the accumulation of HCB in adipose tissue in excess of 0.5 p.p.m. After 7 weeks, birds were taken off rations containing HCB. After a withdrawal period of five weeks, 0.5 p.p.m. of HCB remained in adipose tissue of birds that had been fed 0.12 p.p.m. of HCB.

Adipose Tissue↗