Search PubMed⌕ Search

Biomedical subjects

W Galbraith

Publications and source records attributed to W Galbraith.

At least 19 recordsLinked to original sources
PubMed1998

Activation of rat macrophages by Betafectin PGG-glucan requires cross-linking of membrane receptors distinct from complement receptor three (CR3).

PGG-glucan (Betafectin) is a soluble, highly purified yeast (1,3)-beta-glucan with broad anti-infective and immunomodulatory activities. These studies evaluated the ability of PGG-glucan to directly elicit O2- and tumor necrosis factor alpha (TNF-alpha) production by rat leukocytes in vitro. Particulate beta-glucan stimulated O2- production by the rat NR8383 alveolar macrophage cell line and resident rat peritoneal macrophages, but soluble PGG-glucan did not. In contrast, presentation of PGG-glucan to cells after covalent immobilization to a plastic surface caused a direct stimulation of O2- and TNF-alpha production. The O2- response of rat leukocytes to immobilized PGG-glucan was inhibited by soluble PGG-glucan, indicating that cellular responses to both immobilized and soluble PGG-glucan occur via common cell surface receptors. Because complement receptor type three (CR3) has been proposed as a beta-glucan receptor on human leukocytes, NR8383 cells were evaluated for the presence of CR3. Indirect immunofluorescence and flow cytometric analysis showed that despite being responsive to both particulate and immobilized beta-glucans, NR8383 cells expressed no detectable CR3. These results indicate that the beta-glucan receptors on NR8383 cells are not CR3 and suggest that physical presentation plays an important role in inducing pro-inflammatory leukocyte responses to PGG-glucan.

Adjuvants, Immunologic↗
PubMed1995

Pharmacokinetics of antisense oligonucleotides.

Antisense oligonucleotides are promising therapeutic agents for the treatment of life-threatening diseases. Intravenous injection of phosphodiester oligonucleotide analogue (P-oligonucleotide) in monkeys shows that the oligonucleotide is degraded rapidly in the plasma with a half-life of about 5 minutes. Administration of a single dose of the phosphorothioate (S-oligonucleotide) in animals by the intravenous route reveals biphasic plasma elimination. An initial short half-life (0.53 to 0.83 hours) represents distribution out of the plasma compartment and a second long half-life (35 to 50 hours) represents elimination from the body. This elimination half-life was similar when the oligonucleotide was administered subcutaneously. In contrast, methylphosphonate oligonucleotides have an elimination half-life of 17 minutes in mice. S-Oligonucleotide was distributed into most of organs of rats and mice. Liver and kidney were the 2 organs with highest uptake of the oligonucleotide. The S-oligonucleotide was primarily excreted in urine. Up to 30% was excreted in the first 24 hours. Repeated daily intravenous injections of a 25-mer S-oligonucleotide into rats showed that the concentrations in the plasma are at steady-state during the 8 days' administration. The data represented here support the potential utility of phosphorothioate and methylphosphonate oligonucleotides as therapeutic agents in vivo.

Animals↗
PubMed1995

Interleukin-1 receptor antagonist inhibits proteoglycan breakdown in antigen induced but not polycation induced arthritis in the rabbit.

OBJECTIVE: To compare the alterations in proteoglycan metabolism in antigen induced arthritis and polycation induced arthritis and to determine the involvement of interleukin-1 (IL-1) in the cartilage degradation that occurs in these models of rheumatoid arthritis (RA). METHODS: The time course for loss of proteoglycan into the synovial fluid (SF) and inhibition of proteoglycan synthesis, as well as depletion of articular cartilage proteoglycan content, was compared in rabbit antigen arthritis and polycation arthritis. The ability of recombinant IL-1 receptor antagonist IL-1ra to block the acute cartilage loss at 24 h in these models was investigated, compared to its ability to block the cartilage breakdown induced by direct administration of IL-1 in rabbits. RESULTS: Initial loss of cartilage proteoglycan was accompanied by release of high levels of glycosaminoglycan (GAG) into the SF and decrease in proteoglycan synthetic rates in both antigen and polycation induced arthritis SF GAG rapidly returned to control levels, while proteoglycan synthesis and cartilage proteoglycan content remained depressed, suggesting that the inhibition in proteoglycan synthesis prevented recovery to normal levels. GAG loss from the cartilage into the SF in response to IL-1 injection, as well as other effects of IL-1 challenge, was blocked in a dose dependent manner by IL-1ra administered either intraarticularly (ED50 = 160 ng) or intravenously (iv) (ED50 = 0.09mg/kg). In the antigen induced arthritis model, IL-1ra (20 mg/kg, iv -2h) inhibited GAG release by 40%, whereas in polycation induced arthritis no inhibition was observed even with repeated administration of high doses of inhibitor. CONCLUSION: These studies suggest that sustained depression of proteoglycan synthesis may be responsible for the chronic depletion of articular cartilage proteoglycan in the antigen and the polycation model of RA. However, while IL-1 may play a role in the initial breakdown of articular cartilage in antigen induced arthritis, it does not appear to be involved in polycation induced arthritis in the rabbit.

Animals↗
PubMed1994

Antiinflammatory 4,5-diarylpyrroles: synthesis and QSAR.

A series of 2-substituted- and 2,3-disubstituted-4-(4-fluorophenyl)-5-[4-(methylsulfonyl)phenyl]-1H- pyrroles was synthesized and found to be active in the rat adjuvant arthritis model of inflammation. The most active compounds were the 2-halo derivatives in the order of chloro > bromo > iodo. The same pattern of activity was observed for the 2,3-dihalopyrroles. Quantitative structure-activity relationship studies suggested that the activity could be correlated with the molar refractivity and the inductive field effect of the 2-substituent and the lipophilicity of the 3-substituent.

Animals↗
PubMed1993

Interleukin-1 differentially modulates chondrocyte expression of cyclooxygenase-2 and phospholipase A2.

Interleukin-1 beta (IL-1) increases the synthesis of prostaglandins as well as the expression of synovial fluid phospholipase A2 (PLA2) mRNA and activity by chondrocytes. In order to examine the potential involvement of cyclooxygenase in the induction of prostaglandins by IL-1, the effect of IL-1 on rabbit articular chondrocyte expression of cyclooxygenase enzymes was investigated. By Northern analyses, mRNA for cyclooxygenase-2 (COX-2) was found to be constitutively expressed, and its expression was increased in cultures treated for 24 h with IL-1 (100 ng/ml). Cyclooxygenase-1 mRNA was not detected in control or IL-1-treated cultures. IL-1 caused a concentration-dependent increase in steady-state levels of COX-2 message as assessed by slot-blot analyses. Half-maximal induction of the COX-2 message levels was estimated to require 1.2 ng/ml IL-1. In duplicate slot blots probed with a cDNA for synovial fluid PLA2, half-maximal induction of PLA2 mRNA was estimated to require 0.15 ng/ml IL-1, approximately 10-fold less IL-1 than required for COX-2. In addition, maximal increase in COX-2 message levels was only 3-fold as compared with a 13-fold induction of PLA2. No change in message levels for the intracellular protein, actin, was found between control and experimental cultures. Cycloheximide enhanced COX-2 transcript levels, but did not modulate IL-1 induction of COX-2. Actinomycin D did not inhibit IL-1 augmentation of COX-2 mRNA levels; whereas, induction of PLA2 mRNA levels was completely inhibited, implicating transcriptional mechanisms in the induction of PLA2 but not COX-2 mRNA. These data demonstrate that chondrocyte expression of COX-2 and synovial fluid PLA2 are differentially modulated by IL-1.

Animals↗
PubMed1993

A novel fluorescence ratiometric method confirms the low solvent viscosity of the cytoplasm.

Two homologous indocyanine dyes, Cy3.18 and Cy5.18, can be used as a ratio pair for fluorometric determination of solvent viscosity. Succinimidyl ester derivatives of these dyes can be attached to inert carrier macromolecules, such as Ficoll 70, for measurement of intracellular or intravesicular solvent viscosity. When the viscosity of the solvent was varied by various methods, the fluorescence intensity ratio (Cy3/Cy5) in a mixture of Cy3.18-Ficoll 70 (Cy3F70) and Cy5.18-Ficoll 70 (Cy5F70) in solution was found to be solely a function of solvent viscosity and was insensitive to other solvent parameters such as dielectric constant, temperature, and the ability of the solvent to form hydrogen bonds. Most important, it was insensitive to the presence of large macromolecules, such as proteins, which increase the shear viscosity but have little effect on solvent viscosity. Following microinjection into the cytoplasm of living tissue culture cells, no binding of Cy3F70 or Cy5F70 to intracellular components was detected by fluorescence recovery after photobleaching. Fluorescence intensity ratio imaging of Cy3F70 and Cy5F70 in non-motile interphase CV1 and PtK1 cells showed that the solvent viscosity of cytoplasm was not significantly different from water and showed no spatial variation.

Biophysical Phenomena↗
PubMed1993

Remapping disparate images for coincidence.

With the development of complex multimode computerized microscope systems, it is possible and necessary to obtain images of the same area of the microscopical preparation by several methods of microscopy, such as differential interference contrast, reflection interference microscopy, several wavelengths of fluorescence microscopy, laser scanning and confocal modes. Thus, varied information may be obtained about a single field, in the form of a set of images, taken at different ports of the microscope, using different digitizing cameras, each appropriate to certain tasks. For comparative purposes, the images should be superimposable, pixel by pixel, but in general they are not--they differ in image shape and size, magnification, distortion, centration and orientation. This paper shows how the problem may be approached, using an extension of the remapping procedures described in a previous paper, in which images of a separate grid reference slide are used to detect, quantify and correct the image errors. Affine remapping, without the use of grid images, is also described.

Cells, Cultured↗
PubMed1991

Imaging cytometry by multiparameter fluorescence.

A system is described for performing multicolor fluorescence image cytometry of cell preparations. After the setting up stage, the operation is automatic: the microscope fields are found and focused; then images are acquired for each fluorophore, corrected and analyzed, without any operator interaction. Human peripheral blood lymphocytes on microscope slides were used as a test system. In these experiments, three fluorescent antibodies were used to identify lymphocyte sub-populations, and a DNA content probe was used to identify all nucleated cells. The cell subset percentages determined by image cytometry were comparable to percentages obtained when cells from the same preparation were analyzed by flow cytometry. Multicolor fluorescence imaging cytometry can potentially be extended to the analysis of cells in smears, fine needle biopsies, imprints, and tissue sections.

Algorithms↗
PubMed1991

Effects of IL-1 muteins on cartilage degradation and as inducers of acute inflammation.

IL-1 peptides with N-terminal amino acid mutations were cloned and expressed to help characterize structural requirements for activity. Addition of Thr-Asn to the N-terminus (DP516) or substitution of the first two residues (Ala-Pro) of mature, native IL-1 beta with Thr-Met (DuP118) had no effect on the potency of the muteins in stimulating proteoglycan breakdown and inhibiting proteoglycan synthesis in vitro, or inducing mouse paw swelling in vivo. When Arg in position 4 of DuP118 was replaced by Glu (Glu-4), proteoglycan-synthesis-inhibitory activity was reduced to 20% and proteoglycan-degrading activity to 2% of that induced by native IL-1 beta. Glu-4 was much less active in inducing mouse paw swelling and gave maximal swelling about 40% that of native IL-1 beta. The data suggest that the presence of the positively charged side chain of Arg in position 4 may be important for the activity of IL-1 and may be useful in designing specific IL-1 receptor agonists/antagonists.

Amino Acid Sequence↗
PubMed1990

In vivo inhibition of tumor growth of B16 melanoma by recombinant interleukin 1 beta. II. Mechanism of inhibition: the role of polymorphonuclear leukocytes.

Recombinant human interleukin 1 beta (IL 1 beta) inhibits growth of B16 melanoma in syngeneic C57BL/6 mice in a dose-dependent manner when given intratumorally, intradermally, or intramuscularly over a period of 5 to 7 days. Inhibition of tumor growth was rapid and measurable within 3 days after the initial injection and occurred regardless of the route of injection. However, only intratumoral (ITU) injections of IL 1 beta resulted in greater than 90% inhibition in tumor growth. This enhanced inhibition of tumor growth was not dependent on T or NK cells since inhibition of tumor growth occurred in nude and Beige mice. Also, a profound lymphopenia occurred in mice receiving IL 1 beta. Inhibition of tumor growth did correlate with an increase in the number of polymorphonuclear leukocytes (PMN's) in the circulation. However, only ITU injections of IL 1 beta increased the number of PMN's within the tumors. IM injections of IL 1 beta, while increasing the number of PMN's in the circulation, did not increase the influx of PMN's into the tumors. Furthermore, the transfer of PMN's directly into B16 tumors caused a 49% reduction in tumor growth without the presence of IL 1 beta. These results suggest that in vivo, PMN's may effectively control the growth of tumors and that IL 1 beta may increase this effectiveness by increasing the number of PMN's in the circulation and by locally stimulating the production of chemotactic factors for PMN's within the tumor.

Animals↗
PubMed1990

2-substituted-1-naphthols as potent 5-lipoxygenase inhibitors with topical antiinflammatory activity.

The synthesis, biological evaluation, and structure-activity relationships of a series of 1-naphthols bearing carbon substituents at the 2-position are described. These compounds are potent inhibitors of the 5-lipoxygenase from RBL-1 cells and also inhibit bovine seminal vesicle cyclooxygenase. Structure-activity relationships for these two enzymes are different, implying specific enzyme inhibition rather than a nonspecific antioxidant effect. 2-(Aryl-methyl)-1-naphthols are among the most potent 5-lipoxygenase inhibitors reported (IC50 values generally 0.01-0.2 microM) and show excellent antiinflammatory potency in the mouse arachidonic acid ear edema model. To study the effects of structure on in vitro and in vivo activity, four general features of the molecules were varied: the 2-substituent, the 1-hydroxyl group, substitution on the naphthalene rings, and the 1,2-disubstituted naphthalene unit itself. 2-Benzyl-1-naphthol (5a, DuP 654) shows a very attractive profile of topical antiinflammatory activity and is currently in clinical trials as a topically applied antipsoriatic agent.

Animals↗
PubMed1990

Anti-inflammatory and safety profile of DuP 697, a novel orally effective prostaglandin synthesis inhibitor.

DuP 697 (5-bromo-2[4-fluorophenyl]-3-[4-methylsulfonylphenyl]-thiophene) is a potent inhibitor of paw swelling in nonestablished and established adjuvant arthritis in rats (ED50 = 0.03 and 0.18 mg/kg/day, respectively). DuP 697 had no effect on phenylquinone writhing in rats (ED50 greater than 100 mg/kg), but was analgetic against inflammation-related pain in the Randall-Selitto assay (ED30 = 3.5 mg/kg) and was a very potent antipyretic agent (ED50 = 0.05 mg/kg). The drug was not ulcerogenic in rats at single doses up to 400 mg/kg. DuP 697 (5 mg/kg i.v.) did not alter renal blood flow or the renal vascular response to angiotensin II in furosemide-pretreated, volume-depleted rats. In contrast, indomethacin (5 mg/kg i.v.) decreased renal blood flow and potentiated the renal vascular response to angiotensin II in these animals. DuP 697 was a moderate inhibitor of bull seminal vesicle prostaglandin (PG) synthesis (IC50 = 2.4 X 10(-5) M) and a potent inhibitor of rat brain PG synthesis (IC50 = 4.5 X 10(-6) M) but was ineffective against rat kidney PG synthesis (IC50 7.5 X 10(-5) M). These differential effects of DuP 697 on PG synthesis by various tissues may account for its high potency as an anti-inflammatory and antipyretic agent and its minimal toxicity profile.

Administration, Oral↗
PubMed1989

Interleukin-1 beta stimulates phospholipase A2 mRNA synthesis in rabbit articular chondrocytes.

A cDNA that codes for human rheumatoid synovial fluid phospholipase A2 (PLA2) hybridized with a RNA of the same size (900 base pairs) isolated from rabbit articular chondrocytes (RAC). Treatment of RAC with 100 ng/ml recombinant human interleukin-1 beta (IL-1) for 24 hours caused a 13-fold increase in mRNA for this PLA2. Timecourse studies demonstrated that maximal induction of PLA2 mRNA occurred by 16 hours post addition of IL-1 (100 ng/ml). Augmentation of RAC PLA2 mRNA levels was dose-dependent; half-maximal induction was estimated to require 0.15 ng/ml IL-1. Actinomycin D inhibited IL-1 effects on PLA2 mRNA levels. Coordinate effects of IL-1 on RAC PLA2 activity were observed with respect to time and dose dependence as well as actinomycin D sensitivity.

Animals↗
PubMed1989

Design and synthesis of conformationally restricted phospholipids as phospholipase A2 inhibitors.

The use of conformationally restricted phospholipids 1 and 2 has been employed to understand the conformational preference of phospholipase A2 (PLA2) for substrate phospholipids. Inhibition of porcine pancreatic PLA2 with 1 and 2 indicated a two- to fivefold preference for the distal isomer 2 over the proximal isomer 1. Based upon these studies, both side-chains of the substrate phospholipid appear to occupy the lipid binding domains near the active site with the side-chains further apart most preferred by PLA2.

Animals↗
PubMed1989

Topical anti-inflammatory activity of DuP 654, a 2-substituted 1-naphthol.

Recent work suggests that one of the common biochemical characteristics of skin inflammatory diseases such as psoriasis is altered arachidonic acid metabolism with elevated levels of prostaglandins and leukotrienes. DuP 654, a 2-substituted 1-naphthol, is an exceptionally potent inhibitor of 5-lipoxygenase. DuP 654 was tested in various models of skin inflammation and was found to be potent at inhibiting edema induced by the topical application of arachidonic acid, tetradecanoyl phorbol acetate or the calcium ionophore A23187. DuP 654 was also effective in a murine model of contact sensitivity. DuP 654 was effective at reducing the numbers of infiltrating polymorphonuclear leukocytes in AA and TPA induced edema. These data, taken together, suggest that DuP 654 may be effective in treating human skin diseases.

Administration, Topical↗