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Biomedical subjects

J Travers

Publications and source records attributed to J Travers.

13 recordsLinked to original sources
PubMed2001

Evidence for the involvement of the NADPH oxidase enzyme complex in the optimal accumulation of Platelet-activating factor in the human cell line PLB-985.

Platelet-activating factor (PAF) is an early product of the inflammatory environment, influencing development and resolution of inflammation. Its production is greater in neutrophils and macrophages, which predominantly synthesize 1-alkyl sn-2 acetyl glycerophosphocholine (GPC) than in nongranulocytes (B cells and endothelial cells), which lack a respiratory burst and synthesize 1-acyl sn-2 acetyl GPC as their major PAF species. This study investigated whether the respiratory burst was responsible for the quantitative and qualitative differences in sn-2 acetyl GPC species generation by neutrophils and macrophages versus those cells lacking the NADPH oxidase complex. The myeloid cell line PLB-985 (capable of differentiation into neutrophils) was used to test this hypothesis, since these cells had previously been generated with a non-functional respiratory burst (X-CGD PLB-985). Differentiated PLB-985 cells underwent a large respiratory burst in response to PMA (phorbol ester), and smaller respiratory bursts in response to A23187 (calcium ionophore), and the bacterial polypeptide fMLP (receptor mediated activation). Concurrently, treated cells were assessed for production of 1-hexadecyl and 1-palmitoyl sn-2 acetyl GPC species by gas chromatography/mass spectrometry. Neither cell type generated these lipid species in response to PMA, but both cell types generated equal levels of sn-2 acetyl GPC in response to A23187, with five times more 1-hexadecyl than 1-palmitoyl species. Upon fMLP activation, X-CGD PLB-985 cells produced significantly less 1-hexadecyl and 1-palmitoyl sn-2 acetyl GPC in comparison to the wild-type PLB-985 cells. These findings suggest phagocytic oxidant production by NADPH oxidase is not essential for sn-2 acetyl GPC generation, but appears important for optimal production of PAF in response to some stimuli.

Calcimycin↗
PubMed1998

Antiinflammatory activity of the platelet-activating factor receptor antagonist A-85783.

Accumulating evidence suggests an important role for the lipid mediator, platelet-activating factor (PAF), in cutaneous inflammation. In these studies the antiinflammatory effects of the potent and selective lipophilic PAF receptor antagonist A-85783 topically applied to the ventral ears of male Wistar rats were assessed. Intradermal injections of PAF into rat ears resulted in cutaneous inflammation as assessed by both ear thickness measurements and histological evaluation. Pretreatment of the ears with A-85783 resulted in an inhibition of subsequent PAF-induced inflammation. A-85783 treatment also inhibited phorbol myristic acetate-induced cutaneous inflammation, suggesting that the PAF receptor is involved in the etiology of this experimental dermatitis. These findings demonstrate that epicutaneous A-85783 is an appropriate tool to study the role of the PAF receptor in cutaneous inflammation, and suggest the possible clinical utility of this new class of antiinflammatory agents.

Animals↗
PubMed1992

Beta-oxidation of 12(S)-hydroxy-5,8,10,14-eicosatetraenoic acid by MOLT-4 lymphocytes.

MOLT-4 lymphocytes metabolize 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12(S)-HETE via beta-oxidation with retention of the hydroxyl group at the omega 9 carbon atom. The isolation of 6-hydroxy-4,8-tetradecadienoic acid documents that these cells have the capacity to catabolize the conjugated diene system. 12(S)-HETE was also metabolized to 3,12-dihydroxy-8,10,14-eicosatrienoic acid and 1,9-dihydroxy-5,7,11-heptadecatriene as well as to 17- and 19-carbon aldehydes. When MOLT-4 cells were incubated with the beta-oxidation product, 10-hydroxy-6,8,12-octadecatrienoic acid, it was in part further catabolized but in addition it served as an anabolic precursor as defined by the accumulation 3,12-dihydroxy-8,10,14-eicosatrienoic acid as well as 1,11-dihydroxy-7,9,13-nonadecatriene. Neither 10-hydroxy-6,8,12-octadecatrienoic acid nor 13-hydroxy-5,8,11-octadecatrienic acid was as potent in inhibiting phytohemagglutin-induced lymphocyte mitogenesis as were their parent compounds--i.e., 12(S)- and 15(S)-HETE. These findings argue against the hypothesis that beta-oxidation products of 12(S)- and 15(S)-HETE are the potential modulators of lymphocyte function. However, neither the pathway for synthesis, nor the role of odd chain aldehydes and diols as potential lipid mediators was determined in this study.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1990

Metabolism of 13-hydroxy-9,11-octadecadienoic acid by MOLT-4 lymphocytes.

MOLT-4 lymphocytes metabolize 13-hydroxy-9,11-octadecadienoic acid, via the beta-oxidation pathway with retention of the omega 6 hydroxyl group and the conjugated diene system. The products which accumulate include 11-hydroxy-7,9-hexadecadienoic acid and 9-hydroxy-5,7-tetradecadienoic acid. In addition, it was possible to isolate two beta-hydroxy acids which were shown to be 3,13-dihydroxy-9,11-octadecadienoic acid and 3,11-dihydroxy-7,9-hexadecadienoic acid. The odd chain aldehyde, 12-hydroxy-8,10-heptadecadien-1-al, also was detected. However, neither the pathway nor the immediate precursor for the synthesis of this compound was established.

Adult↗
PubMedDate not supplied

The evaluation of child behavior during dental examination and treatment using predmedication and placebo.

The purpose of this study were to determine the association of scores on the North Carolina Behavior Rating Scale (NCBRS) to those of the Frankl scale during restorative visits; and to quantify and compare rated behavior of children during an oral examination and restorative visits involving either a placebo or a combination of chloral hydrate (CH) and hydroxyzine. Fifteen patients 21-37 months old participated in this institutionally approved study. The study was a double-blind, crossover design. Following an examination using a mirror, explorer, and prophylaxis cup, the child received either a placebo or a combination of chloral hydrate (CH) and hydroxyzine. Fifteen patients 21-37 months old participated in this institutionally approved study. The study was a double-blind, crossover design. Following an this institutionally approved study. The study was a double-blind, crossover design. Following an examination using a mirror, explorer, and prophylaxis cup, the child received either a placebo or a combination of chloral hydrate and hydroxyzine. The sequence was reversed at the next appointment. All exam and treatment visits were videotaped and analyzed using the NCBRS. In addition, all treatment visits were rated with the Frankl scale. The data were analyzed using a repeated ANOVA and correlation coefficients. The results showed a high interrater reliability (> 86% agreement) and a significant correlation between the NCBRS and Frankl scale (P < 0.001). No significant difference was found for the amount of disruptive behavior among oral examination, placebo, and medication visits (P < or = 0.097), although a consistent decrease in mean disruptive behavior for that order of visits was observed most frequently.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗