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Biomedical subjects

R E Miller

Publications and source records attributed to R E Miller.

At least 37 records · Page 2Linked to original sources
PubMed2001

Cyclosporin A effects during primary and secondary activation of human umbilical cord blood T lymphocytes.

OBJECTIVE: Cyclosporin A (CsA), effective in prophylaxis and treatment of graft-vs-host disease (GVHD) after human allogeneic transplantation, blunts T-cell responses by inhibiting nuclear factor of activated T cells-1 (NFAT1) activation. This laboratory has shown that NFAT1 protein expression is severely reduced in human UCB (umbilical cord blood) T cells. Since UCB is increasingly used as a hematopoietic stem cell source in allogeneic transplantation, it is important to determine whether CsA sensitivity in UCB differs from that of adult T cells. METHODS: Surface flow cytometric analysis, intracellular cytokine staining, flow cytometric analysis of cell death, and thymidine incorporation were used in this study to determine T-cell activation and effector functions during primary and secondary stimulation in the presence of CsA. RESULTS: Although we observed differential CsA sensitivity of T-cell activation marker (CD69, CD45RO, CD25) upregulation comparing UCB and adult, we did not observe any significant difference in CsA sensitivity of T-cell effector functions. Importantly, we observed reduced IFN-gamma and TNF-alpha expression in UCB T cells both in primary and secondary stimulation, as well as increased rates of activation-induced cell death (AICD). CONCLUSION: Thus, our studies do not support the previous hypothesis that reduced GVHD observed after UCB transplantation is attributable to increased CsA sensitivity of UCB T cells. Rather, reduced UCB T-cell cytokine production and increased AICD may be important cellular mechanisms underlying these favorable rates of GVHD in UCB transplant recipients.

Adult↗
PubMed2001

Spiers Memorial Lecture. Comparative studies of cluster dynamics in the gas and condensed phases.

Although an overview of the field of cluster dynamics is impossible to give in this Introductory Lecture, several important themes have emerged that can provide a backdrop for this Faraday Discussion. As a result, the first part of this paper introduces some of these themes, using results from the literature to illustrate some of the important issues. Although much of the work on clusters is being carried out in the gas phase (usually in free jet expansions and molecular beams), new approaches have recently been developed that permit the study of the same complexes in or on nanoscale clusters. In particular, recent developments in the field of superfluid helium droplet spectroscopy (SHEDS) permit high-resolution studies of atoms, molecules and clusters in this exotic quantum fluid. After introducing this new field, the author will discuss experiments from his own laboratory to illustrate some of the capabilities of the technique.

Journal Article↗
PubMed2001

Noncontact quantitative spatial mapping of stress and flexural rigidity in thin membranes using a picosecond transient grating photoacoustic technique.

This paper describes a purely optical technique for measuring and spatially mapping out stress and rigidity in thin membranes. Its application to a membrane of aluminum nitride that has significant spatial nonuniformities in its elastic properties demonstrates the method. The attractive features of this technique--fast, noncontacting measurement, good spatial resolution, ability to quantify in-plane anisotropy--make it potentially useful for characterizing elements of microelectromechanical structures, masks for advanced lithography systems, acoustic filters, and other devices in which the mechanical properties of membranes are important.

Journal Article↗
PubMed2000

Quantitative determination of dipalmitoylphosphatidylcholine and palmitic acid in porcine lung surfactants used in the treatment of respiratory distress syndrome.

A high-performance liquid chromatography (HPLC) method was developed that can separate and quantify dipalmitoylphosphatidylcholine and its degradation product, palmitic acid from various phospholipids contained in a porcine lung surfactant used in the treatment of respiratory distress syndrome, which was recently approved for use by the FDA. The method used a C8 reversed-phase HPLC column with a (50:45:10) acetonitrile/methanol/acetic acid mobile phase, and refractive index detection. The active component of the lung surfactant, dipalmitoylphosphatidylcholine (DPPC) and palmitic acid (PA), could be quantified following a liquid-liquid extraction procedure along with an internal standard, dimyristoylphosphatidylcholine (DMPC). The assay was validated for linearity, accuracy, precision, reproducibility and ruggedness. Column stability was measured by performing the assay over time and monitoring the system suitability parameters. The extraction procedure has a 90% recovery and the assay is linear over a range of 5 microg/ml to 300 microg/ml. The assay is used to release commercial product and monitor stability of existing lots of material.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2000

Synthesis and antimalarial activity of sixteen dispiro-1,2,4, 5-tetraoxanes: alkyl-substituted 7,8,15,16-tetraoxadispiro[5.2.5. 2]hexadecanes.

Sixteen alkyl-substituted dispiro-1,2,4,5-tetraoxanes (7,8,15, 16-tetraoxadispiro[5.2.5.2]hexadecanes) were synthesized to explore dispiro-1,2,4,5-tetraoxane SAR and to identify tetraoxanes with better oral antimalarial activity than prototype tetraoxane 1 (WR 148999). The tetraoxanes were prepared either by peroxidation of the corresponding cyclohexanone derivatives in H(2)SO(4)/CH(3)CN or by ozonolysis of the corresponding cyclohexanone methyl oximes. Those tetraoxanes with alkyl substituents at the 1 and 10 positions were formed as single stereoisomers, whereas the five tetraoxanes formed without the stereochemical control provided by alkyl groups at the 1 and 10 positions were isolated as mixtures of diastereomers. Three of the sixteen tetraoxanes were inactive (IC(50)'s > 1000 nM), but five (2, 6, 10, 11, 12) had IC(50)'s between 10 and 30 nM against the chloroquine-sensitive D6 and chloroquine-resistant W2 clones of Plasmodium falciparum compared to corresponding IC(50)'s of 55 and 32 nM for 1 and 8.4 and 7.3 nM for artemisinin. We suggest that tetraoxanes 13, 16, and 17 were inactive and tetraoxanes 4 and 7 were weakly active due to steric effects preventing or hindering peroxide bond access to parasite heme. Tetraoxanes 1, 10, 11, and 14, along with artemisinin and arteether as controls, were administered po b.i.d. (128 mg/kg/day) to P. berghei-infected mice on days 3, 4, and 5 post-infection. At this dose, tetraoxanes 10, 11, and 14 cured between 40% and 60% of the infected animals. In comparison, artemisinin and tetraoxane 1 produced no cures, whereas arteether cured 100% of the infected animals. There was no apparent relationship between tetraoxane structure and in vitro neurotoxicity, nor was there any correlation between antimalarial activity and neurotoxicity for these seventeen tetraoxanes.

Alkanes↗
PubMed2000

Mice lacking flt3 ligand have deficient hematopoiesis affecting hematopoietic progenitor cells, dendritic cells, and natural killer cells.

The ligand for the receptor tyrosine kinase fms-like tyrosine kinase 3 (flt3), also referred to as fetal liver kinase-2 (flk-2), has an important role in hematopoiesis. The flt3 ligand (flt3L) is a growth factor for hematopoietic progenitors and induces hematopoietic progenitor and stem cell mobilization in vivo. In addition, when mice are treated with flt3L immature B cells, natural killer (NK) cells and dendritic cells (DC) are expanded in vivo. To further elucidate the role of flt3L in hematopoiesis, mice lacking flt3L (flt3L-/-) were generated by targeted gene disruption. Leukocyte cellularity was reduced in the bone marrow, peripheral blood, lymph nodes (LN), and spleen. Thymic cellularity, blood hematocrit, and platelet numbers were not affected. Significantly reduced numbers of myeloid and B-lymphoid progenitors were noted in the BM of flt3L-/- mice. In addition a marked deficiency of NK cells in the spleen was noted. DC numbers were also reduced in the spleen, LN, and thymus. Both myeloid-related (CD11c(++) CD8alpha(-)) and lymphoid-related (CD11c(++) CD8alpha(+)) DC numbers were affected. We conclude that flt3L has an important role in the expansion of early hematopoietic progenitors and in the generation of mature peripheral leukocytes.

Animals↗
PubMed2000

Clinical presentation and antiviral therapy for poxvirus infection in pudu (Pudu puda).

A severe poxvirus infection occurred in three pudu (Pudu puda), resulting in two fatalities. Cutaneous ulcers with mucopurulent exudate were present around the eyes and nose, at the lip margins, coronary bands, and teats. Mucosal ulcers were present in the oral cavity, esophagus, and forestomachs. In the two fatalities, a secondary disseminated fungal infection also occurred. Affected animals were leukopenic, hypocalcemic, and hyperphosphatemic and had elevated serum alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase levels. Electron microscopic examination of affected skin confirmed the presence of a poxvirus. Neutralizing antibody titers to this virus were present in the two pudu tested. One case was treated with cidofovir, 5 mg/kg i.v. q7d for four treatments. Complete recovery occurred in the treated animal. This is the second report of poxvirus infection in pudu and the first report describing clinical presentation, presence of secondary disseminated fungal infection, and successful treatment.

Animal Diseases↗
PubMed1999

Reduced NFAT1 protein expression in human umbilical cord blood T lymphocytes.

Umbilical cord blood (UCB) stem cells from related and unrelated allogeneic donors have emerged as novel treatment for patients with hematologic malignancies. The incidence and severity of acute graft-versus-host disease (GVHD) after UCB transplantation compares favorably with that observed in recipients of matched unrelated donor allogeneic grafts, but remains a major cause of morbidity and mortality. It has been shown that stimulated lymphocytes from UCB have reduced production of cytokines including interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), which play a role in GVHD pathophysiology. We investigated the molecular mechanisms underlying this reduced cytokine production by analyzing expression of nuclear factor of activated T cells-1 (NFAT1) in UCB T cells. We detected no constitutive expression of NFAT1 protein in unstimulated UCB T cells compared with adult T cells. Moreover, although NFAT1 expression in UCB T cells was upregulated after prolonged (40 hours) T-cell stimulation, it was only partially upregulated when compared with adult controls. Our observation of minimal NFAT1 expression after stimulation correlated with reduced cytoplasmic IFN-gamma and TNF-alpha production in UCB T cells studied simultaneously. Reduced NFAT1 expression may blunt amplification of donor UCB T-cell alloresponsiveness against recipient antigens, thereby potentially limiting GVHD incidence and severity after allogeneic UCB transplantation.

Adult↗
PubMed1999

Synergistic action of fms-like tyrosine kinase 3 ligand and CD40 ligand in the induction of dendritic cells and generation of antitumor immunity in vivo.

Daily treatment of mice with fms-like tyrosine kinase 3 ligand (Flt3L) leads to a significant increase in the number of dendritic cells and induces antitumor immunity. Here, we show that Flt3L and CD40 ligand (CD40L) synergize in the generation of immune responses against two poorly immunogenic tumors, leading to complete tumor rejection in a high proportion of mice. Rechallenge of the Flt3L + CD40L-treated mice with the immunizing tumor resulted in complete inhibition of tumor growth, indicating that these animals had developed long-lasting antitumor immunity. In addition, we demonstrate that endogenous CD40L plays a critical role in antitumor immunity, since blockade of CD40-CD40L interactions in vivo prevents the generation of antitumor immunity in therapeutic and vaccination protocols. Dendritic cells generated in mice treated with Flt3L alone or in combination with CD40L were equally potent in stimulating allogeneic T cells and expressed similar levels of MHC class II, CD80, and CD86. However, mice treated with Flt3L + CD40L had significantly more dendritic cells than mice treated with either of the cytokines alone, suggesting that CD40L promotes the proliferation and/or survival of dendritic cells generated by Flt3L treatment. Dendritic cells generated in this manner are likely to be involved in the priming of antitumor immune responses.

Adjuvants, Immunologic↗
PubMed1999

Demonstration of therapeutic equivalence of generic and innovator beclomethasone in seasonal allergic rhinitis. SAR Study Group.

BACKGROUND: Although generic formulations of drugs are chemically equivalent, they may not be bioequivalent to the innovator. Since bioequivalence of intranasal corticosteroids has been difficult to demonstrate by pharmacokinetic methods, clinical trials have been necessary to compare generic and innovator agents. OBJECTIVE: We therefore designed a multicenter, randomized double-blind, parallel-group placebo-controlled study to examine the therapeutic equivalence of generic beclomethasone diproprionate to the innovator. METHODS: A total of 518 patients, ages 12 to 60, with ragweed-induced seasonal allergic rhinitis from eight centers were randomized to receive intranasal generic or innovator beclomethasone 42 microg, 84 microg or placebo twice daily for 6 weeks. Efficacy was assessed by means of rhinitis symptom scores as recorded in patient diaries. Adverse events were recorded throughout the study to assess safety. RESULTS: Mean rhinitis composite symptom scores (congestion, postnasal drip, runny nose, and sneezing) were significantly lower in patients receiving 42 microg (P = .0003) or 84 microg (P = .0001) beclomethasone twice daily compared with placebo. Generic beclomethasone was equivalent therapeutically to the innovator in alleviating nasal congestion (42 microg and 84 microg doses), postnasal drip (84 microg dose), runny nose (84 microg dose), sneezing (42 microg and 84 microg doses) and mean composite (42 microg and 84 microg doses) symptom scores during the 6-week study period. Similar and equivalent efficacy was also demonstrated during the 5-day period of peak pollen counts at each site. The type and incidence of drug-related adverse events were similar for both beclomethasone treatment groups and did not differ significantly from placebo in severity and frequency. CONCLUSIONS: Generic beclomethasone was therapeutically equivalent to the innovator in regards to both efficacy and side effect profile in the treatment of ragweed-induced allergic rhinitis.

Administration, Intranasal↗
PubMed1999

Tumoricidal activity of tumor necrosis factor-related apoptosis-inducing ligand in vivo.

To evaluate the utility of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as a cancer therapeutic, we created leucine zipper (LZ) forms of human (hu) and murine (mu) TRAIL to promote and stabilize the formation of trimers. Both were biologically active, inducing apoptosis of both human and murine target cells in vitro with similar specific activities. In contrast to the fulminant hepatotoxicity of LZ-huCD95L in vivo, administration of either LZ-huTRAIL or LZ-muTRAIL did not seem toxic to normal tissues of mice. Finally, repeated treatments with LZ-huTRAIL actively suppressed growth of the TRAIL-sensitive human mammary adenocarcinoma cell line MDA-231 in CB.17 (SCID) mice, and histologic examination of tumors from SCID mice treated with LZ-huTRAIL demonstrated clear areas of apoptotic necrosis within 9-12 hours of injection.

Animals↗
PubMed1999

Patterns of evolutionary rate variation among genes of the anthocyanin biosynthetic pathway.

The anthocyanin biosynthetic pathway is responsible for the production of anthocyanin pigments in plant tissues and shares a number of enzymes with other biochemical pathways. The six core structural genes of this pathway have been cloned and characterized in two taxonomically diverse plant species (maize and snapdragon). We have recently cloned these genes for a third species, the common morning glory, Ipomoea purpurea. This additional information provides an opportunity to examine patterns of evolution among genes within a single biochemical pathway. We report here that upstream genes in the anthocyanin pathway have evolved substantially more slowly than downstream genes and suggest that this difference in evolutionary rates may be explained by upstream genes being more constrained because they participate in several different biochemical pathways. In addition, regulatory genes associated with the anthocyanin pathway tend to evolve more rapidly than the structural genes they regulate, suggesting that adaptive evolution of flower color may be mediated more by regulatory than by structural genes. Finally, for individual anthocyanin genes, we found an absence of rate heterogeneity among three major angiosperm lineages. This rate constancy contrasts with an accelerated rate of evolution of three CHS-like genes in the Ipomoea lineage, indicating that these three genes have diverged without coordinated adjustment by other pathway genes.

Acyltransferases↗
PubMed1999

8-Aminoquinolines active against blood stage Plasmodium falciparum in vitro inhibit hematin polymerization.

From the Walter Reed Army Institute of Research (WRAIR) inventory, thirteen 8-aminoquinoline analogs of primaquine were selected for screening against a panel of seven Plasmodium falciparum clones and isolates. Six of the 13 8-aminoquinolines had average 50% inhibitory concentrations between 50 and 100 nM against these P. falciparum clones and were thus an order of magnitude more potent than primaquine. However, excluding chloroquine-resistant clones and isolates, these 8-aminoquinolines were all an order of magnitude less potent than chloroquine. None of the 8-aminoquinolines was cross resistant with either chloroquine or mefloquine. In contrast to the inactive primaquine prototype, 8 of the 13 8-aminoquinolines inhibited hematin polymerization more efficiently than did chloroquine. Although alkoxy or aryloxy substituents at position 5 uniquely endowed these 13 8-aminoquinolines with impressive schizontocidal activity, the structural specificity of inhibition of both parasite growth and hematin polymerization was low.

Animals↗
PubMed1998

A receptor for the lipocalin placental protein 14 on human monocytes.

Human placental protein 14 (PP14), a member of the lipocalin structural superfamily, is an abundant amniotic fluid glycoprotein with documented immunoinhibitory activities. While receptors have been characterized for several other lipocalins, none have been reported to date for PP14. In the present study, two-color immunofluorescence and flow cytometry was used to screen peripheral blood mononuclear cell subpopulations for their capacity to engage fluoresceinated recombinant PP14. The tagged PP14 bound strongly in a specific and saturable fashion to CD14+ (monocyte lineage) cells, but not to CD20+ (B cell lineage) or CD3+ (T cell lineage) cells. This binding was both pH- and temperature-sensitive, and was reduced by proteolytic pre-digestion of the cells with trypsin or proteinase K. Scatchard analysis demonstrated a single class of receptors on CD14+ cells, with a K(D) of approximately 1 x 10(-8) and approximately 10-35,000 receptors per cell. These findings constitute the first report of a cell surface-associated binding protein for PP14 and set the stage for exploring the molecular mechanisms of PP14-mediated signaling and immunomodulation.

Antigens, CD↗
PubMed1998

The separation of ipratropium bromide and its related compounds.

Ipratropium bromide, the active component in ipratropium bromide metered dose inhalers (MDI), is used as a bronchodilator for the maintenance and treatment of bronchospasms associated with chronic obstructive pulmonary disease (COPD). The separation of ipratropium bromide, tropic acid, N-isopropyl-nor-atropine (NINA), 8-s ipratropium bromide, apo-ipratropium bromide and the excipients found in the formulation is important for analyzing raw materials and stability samples. We now report a reversed-phase HPLC method that can be used for separating ipratropium bromide and its related compounds, using an acetonitrile/potassium phosphate buffer (100 mM, pH 4.0) gradient mobile phase. Previous methods used for separating ipratropium bromide from its related compounds involved reversed-phase ion-pairing HPLC with UV detection. These methods exhibited less reproducibility, less ruggedness and required a high flow rate. The reported method is linear from 10 to 1000 micrograms ml-1 with a limit of detection of 60 ng ml-1. In addition, analysis of samples subjected to accelerated stability conditions showed that all degradants are resolved from the active component, resulting in stability-indicating assay. This assay also saved mobile phase and eliminated problems associated with ion-pairing reagents.

Bronchodilator Agents↗
PubMed1998

Vesicular and ulcerative dermatopathy resembling superficial necrolytic dermatitis in captive black rhinoceroses (Diceros bicornis).

The histopathology, clinical presentation, and epidemiology of a cutaneous and oral mucosal disease affecting 40 black rhinoceroses (Diceros bicornis) at 21 zoological parks (50% of the captive US population) were investigated. Twenty-seven biopsies were examined from recent lesions, and clinical information was available from 127 episodes. The cutaneous lesions began as plaques that progressed to vesicles, bullae, or ulcers. Lesions waxed and waned in individual cases. Lesions were predominantly bilaterally symmetrical, affecting pressure points, coronary bands, tips of the ears and tail, and along the lateral body wall and dorsum. Oral lesions were first noticed as ulcers and were present on the lateral margins of the tongue, palate, and mucocutaneous junctions of the lips. All recent lesions had similar histopathologic findings of prominent acanthosis, hydropic degeneration of keratinocytes in the stratum spinosum, spongiosis, intraepithelial vesicles, and parakeratosis without dermal inflammation. Chronic lesions were ulcerated. No pathogens were identified by culture or electron microscopy. Most episodes coincided with stress events (transportation, sudden cold temperatures, intraspecific harassment, estrus, advanced pregnancy) or concurrent diseases (toxic hepatopathy, hemolytic anemia, respiratory or urinary tract infections). Affected rhinoceroses usually were lethargic and had weight loss. Affected rhinoceroses also had lower hematocrit, serum albumin, and cholesterol values than captive healthy or wild rhinoceroses. The clinical patterns and histopathologic findings are similar to those of superficial necrolytic dermatitis in dogs and necrolytic migratory erythema in humans. The high prevalence of this skin disease in captive black rhinoceroses under many circumstances suggests that their epidermis is acutely sensitive to any disruption of metabolic homeostasis. We propose that metabolic changes secondary to a stress response from maladaptation or nutritional inadequacy of captive diets may contribute to the development of this disease in rhinoceroses without hepatopathies.

Animals↗