PubMed Health⌕ Search

Biomedical subjects

P F Cavanaugh

Publications and source records attributed to P F Cavanaugh.

14 recordsLinked to original sources
PubMed2005

Efficacy of cyclo-oxygenase-2 inhibition by etoricoxib and naproxen on the axial manifestations of ankylosing spondylitis in the presence of peripheral arthritis.

OBJECTIVE: The combined efficacy of selective and non-selective cyclo-oxygenase-2 (COX-2) inhibition on the axial manifestations of ankylosing spondylitis (AS) in the presence or absence of chronic peripheral arthritis was evaluated. METHODS: In a post hoc subgroup analysis of a 6 week, randomised, double blind, placebo controlled trial, 387 patients with active axial AS were randomised to receive etoricoxib 90 mg or 120 mg once a day, naproxen 500 mg twice daily, or placebo. Randomisation was stratified by the presence or absence of chronic peripheral arthritis. The primary outcome measure was the time weighted average change from baseline of spine pain intensity. Efficacy data from the three groups receiving active treatment (the NSAID/COX-2 inhibitor group) were combined to improve precision. An analysis of covariance model was used to evaluate the effect of peripheral disease on treatment response. RESULTS: 93 patients were allocated to receive placebo and 294 to active treatment (naproxen or etoricoxib). The combined NSAID/COX-2 inhibitor group had a significant treatment response compared with the placebo group for all efficacy measures, both in patients with and without peripheral arthritis. A significantly greater difference in mean patient assessment of spine pain was found between active and placebo treatments in patients without compared with those with peripheral arthritis (p = 0.005; -32.5 mm v -17.0 mm, respectively). Similar differences, although not statistically significant, were seen for other end points. CONCLUSION: NSAIDs and COX-2 inhibitors have a clinically relevant symptomatic effect on axial AS irrespective of the presence of peripheral arthritis. In this exploratory analysis spinal improvement appeared to be greater in patients without peripheral disease.

Adolescent↗
PubMed2000

Cyclooxygenase regulates human oropharyngeal carcinomas via the proinflammatory cytokine IL-6: a general role for inflammation?

High levels of prostaglandins are produced in human oropharyngeal carcinoma (OPC). Five human OPC cell lines tested expressed both isoforms of cyclooxygenases (COX). The pan-COX inhibitor ketorolac continuously and significantly decreased PGE(2) production and IL-6 and IL-8 levels in all OPC cell lines tested, but did not affect IL-1alpha, GM-CSF levels, or in vitro tumor cell growth. In contrast, ketorolac reduced OPC growth in vivo. The OPC cell lines used express the IL-6 receptor, and IL-6 stimulation of these cells causes transduction to occur via STAT3 pathway activation. Coincubation with OPC cell lines with conditioned medium from a TPA-exposed HL-60 cells stimulated growth proportional to the IL-6 levels measured in the conditioned medium. This growth effect was specifically inhibited by anti-IL-6 antibody. These results are consistent with cytokine products of inflammatory cells having paracrine growth effects on OPC. If chronic inflammation plays a role in promoting the development of OPC, this mechanism may also apply to other epithelial tumor systems modulated by COX activity.

Animals↗
PubMed1998

Coordinate production of PGE2 and IL-1 beta in the gingival crevicular fluid of adults with periodontitis: its relationship to alveolar bone loss and disruption by twice daily treatment with ketorolac tromethamine oral rinse.

The inflammatory mediators prostaglandin E2 (PGE2) and interleukin-1 beta (IL-1 beta) play critical roles in the inflammatory process leading to alveolar bone and connective tissue loss in periodontal disease. Data from a previously published 6-month clinical study demonstrated that twice daily use of 0.1% ketorolac tromethamine oral rinse prevented alveolar bone loss in adults with periodontitis. We further analyzed data from this study to examine the relationship between PGE2. IL-1 beta and bone loss. Patient mean PGE2 and IL-1 beta levels in gingival crevicular fluid (M-GCF) measured throughout the course of the study were directly compared to the maximum amount of alveolar bone height loss observed at a single study site in each patient. The maximum amount of bone loss measured was chosen for the analysis since the pattern of bone loss was clearly episodic in nature. A statistically significant correlation (r = 0.73, p = 0.001) exists between M-GCF PGE2 concentration and the maximum amount of bone height lost at individual patient study sites. The correlation between M-GCF IL-1 beta concentration and maximum bone height lost is also statistically significant (r = 0.66, p = 0.005). Over the 6-month duration of the study, both PGE2 and IL-1 beta were coordinately expressed in the placebo treatment group as reflected in the significant correlation between M-GCF concentrations of the 2 mediators (r = 0.81, p < 0.001). Treatment of patients with 0.1% ketorolac tromethamine twice daily for 6 months resulted in reductions of PGE2 in GCF and a negligible correlation between M-GCF PGE2 and M-GCF IL-1 beta (r = 0.42, p = 0.088). This lack of a strong association between the 2 mediators in the ketorolac treatment group provides a direct biochemical readout of the anti-inflammatory efficacy of ketorolac tromethamine oral rinse in patients with periodontitis. Further studies are warranted to determine the full diagnostic potential of M-GCF levels of PGE2 and IL-1 beta for predicting risk of alveolar bone loss in patients with periodontitis and monitoring periodontal therapy effectiveness.

Adult↗
PubMed1996

Efficacy of quantitative digital subtraction radiography using radiographs exposed in a multicenter trial.

Digital subtraction radiography (DSR) has been shown to be a sensitive and specific method for the detection of small bony changes in periodontitis. The purpose of this study was to perform a multicenter validation of the DSR in human subjects. Seventeen subjects were enrolled at 3 centers. Feather-edged hydroxyapatite chips (approximately 1, 7 and 10 mg) were used to simulate osseous lesions. Bilateral radiographs were taken with and without chips. Geometry was standardized using a cephalostat and the order of radiographs was determined using a randomization plan. Radiographs were subtracted, lesions isolated, and quantified at a single center without knowledge of the randomization code or location of the chips used in each subject. The overall sensitivity and specificity in detecting 1 mg changes was 87.8% and 100%, respectively. Sensitivity and specificity in detecting 7 mg and 10 mg chips was 100%. A strong linear relationship between actual lesion mass and calculated mass was observed (R2 = 0.94, slope = 0.98, p < 0.0001). No significant differences were observed by center. These data indicate that the DSR is a valid technique for the assessment of alveolar bone changes in multicenter trials.

Adult↗
PubMed1996

Validation of quantitative digital subtraction radiography using the electronically guided alignment device/impression technique.

The electronically guided alignment device (EGAD) has been demonstrated to function well with a custom fabricated stent for taking radiographs for subtraction. The objective of this study is to demonstrate that this device functions well when used with an impression bite-block rather than a full arch acrylic stent. Nineteen subjects participated. Two vinyl siloxane impressions were made for each subject and a pair of x-rays was taken with each impression. The location for study was divided among 7 for the maxillary premolar-1st molar region, 6 for the mandibular premolar-1st molar region, and 6 for the incisor-canine region. To simulate bone change 3 bone chips (approximately 1, 7, and 10 mg) were positioned in the mucobuccal fold when one of each pair of x-rays was taken. Pairs of radiographs were subtracted and the bone change (chips) isolated by thresholding to determine their area. An aluminum ramp was used to determine volume. A strong linear relationship between actual chip weight and equivalent aluminum volume (r2 = 0.64, P < 0.001) was obtained for all regions of the mouth when considered together. The strongest relationship of the 3 regions was for mandibular premolar-1st molar sites, r2 = 0.78. These data indicate that the EGAD/impression technique is suitable for taking radiographs in all areas of the mouth for quantitative digital subtraction.

Adult↗
PubMed1996

The activation of murine macrophages and natural killer cells by the partially thiolated double stranded RNA poly(I)-mercapto poly(C).

Partially thiolated analogs of the biological response modifier poly I.poly C (pI.pC) were synthesized. Each of these analogs (pI.MPC) contained a partially thiolated polycytidylate (MPC) strand containing either 1.2%, 4.6%, or 17% 5-mercaptocytosine (%SH) randomly introduced throughout the polynucleotide. The ability of these double stranded RNAs (dsRNAs) to activate murine peritoneal macrophages in vitro and augment natural killer (NK) cell activity in mice following intraperitoneal (i.p.) administration was determined. Macrophages were treated in vitro for 24 hours with pI.pC, or pI.MPC, washed, and then overlayed with exponentially growing L1210 leukemia cells at an effector to target (E:T) ratio of 25:1. The cytostatic effect of the macrophages on the L1210 cells was determined by 3H.thymidine pulse labelling. The rank order of potency for macrophage activation was determined to be: pI.pC>pI.MPC(1.2% SH)>pI.MPC(4.6% SH)pI.MPC(17% SH). Twenty hours following i.p. administration of 5 mg/kg of each pI.MPC analog, splenic NK cell activity was assessed in a standard 51Cr release assay using the murine tumor target cell line YAC- 1. The rank order of potency observed for NK cell activation was determined to be; pI.pCpI MPC(1.2% SH)>pI.MPC(4.6% SH)>pI.MPC(17% SH). These dsRNAs activated NK cells in a dose dependent manner. The efficacy and time course for NK cell activation following i.p. administration of pI.MPC (1.2% SH) at a dose of 10 mg/kg was directly compared to an equivalent 10 mg/kg i.p. dose of pI.pC. NK cell activation took place within three hours following treatment with pI-pC whereas the onset of NK cell activation by pI.MPC (1.2%) occurred between 8 and 20 hours post treatment. NK cell activity steadily declined from 24 to 50 hours post treatment at which time the NK activity in both treatment groups was similar. There was a significant correlation between the immunostimulatory potency of these dsRNAs and their experimentally determined melting temperatures (r2 = 0.88) and percent hyperchromicity upon thermal denaturation (r2 = 0.99). At the lower %SH, pI.MPC retains most of the immunostimulatory activities of p1.pC and may serve as a useful and potent biological response modifier.

Animals↗
PubMed1990

A semi-automated neutral red based chemosensitivity assay for drug screening.

A semi-automated colorimetric chemosensitivity assay was developed. The assay utilizes the vital stain neutral red for the rapid screening of potential anticancer agents using solid tumor cell lines. The cell lines used in this assay and presented in this report are CX-1 colon adenocarcinoma and A549 lung carcinoma. The assay, performed in 96 well tissue culture plates, allows for short drug exposure times (3 hrs.) followed by quantitation of cell number (neutral red absorbance) following four cell doubling times. Cell number directly correlated with absorbance of eluted neutral red at 540 nm. However, optimal amounts of dye and staining times varied between cell lines. IC50 concentrations (for inhibition of cell growth) determined using this assay were in good agreement with results from clonogenic assays using similar drug treatment conditions. The assay technique was determined to be capable of detecting antineoplastic compounds operating by a wide variety of mechanisms.

Adenocarcinoma↗
PubMed1985

Biological properties of N4- and N1,N8-spermidine derivatives in cultured L1210 leukemia cells.

Eleven novel spermidine (SPD) derivatives were synthesized as potential anticancer agents and evaluated for their ability to compete with [3H]SPD for cellular uptake, to inhibit cell growth, to affect polyamine biosynthesis, to suppress enzyme activity, and to substitute for SPD in supporting growth of cultured L1210 leukemia cells. The compounds included a series of N4-SPD derivatives (N4-methyl-SPD, N4-ethyl-SPD, N4-acetyl-SPD, N4-hexyl-SPD, N4-hexanoyl-SPD, N4-benzyl-SPD, and N4-benzoyl-SPD) and a series of N1,N8-SPD derivatives [N1,N8-bis(ethyl)-SPD, N1,N8-bis(acetyl)-SPD, N1,N8-bis(propyl)-SPD, and N1,N8-bis(propionyl)-SPD]. Uptake studies revealed N4-alkyl derivatives to be the most effective competitive inhibitors of [3H]SPD uptake (Ki, 26 to 43 microM) followed by N1,N8-alkyl derivatives (Ki, 71 to 115 microM), then N4-acyl derivatives (Ki, 115 to greater than 500 microM), and N1,N8-acyl derivatives (Ki, greater than 500 microM). The data indicate the relative importance of the terminal amines and of charge as determinants of cellular uptake. Of the 11 derivatives, only N4-hexyl-SPD, N1,N8-bis(ethyl)-SPD, and N1,N8-bis(propyl)-SPD demonstrated antiproliferative activity at 0.1 mM with 50%-inhibitory concentration values at 48 h of 30, 40, and 50 microM, respectively. In the case of the N1,N8-SPD derivatives, recovery from growth inhibition was enhanced considerably by exogenous SPD, suggesting involvement of polyamine depletion. At 10 to 30 microM, both N1,N8-bis(ethyl)-SPD and N1,N8-bis(propyl)-SPD (but not N4-hexyl-SPD) inhibited polyamine biosynthesis as indicated by significant reductions in polyamine pools and in biosynthetic enzyme activities. The more effective of the two, N1,N8-bis(ethyl)-SPD, depleted intracellular putrescine and SPD and reduced spermine by approximately 50% at 96 h and decreased ornithine and S-adenosylmethionine decarboxylase activities by 98 and 62%, respectively. Since neither derivative (at 5 mM) directly inhibited these enzymes from untreated cell extracts by significantly more than SPD itself, it is suspected that they act by regulating enzyme levels. As a measure of regulatory potential of the derivatives, ornithine decarboxylase was assayed in cells treated for 24 h and compared to the effects of 10 microM SPD which reduced the enzyme activity by 80%. None of the N4-SPD derivatives affected ornithine decarboxylase activity, while N1,N8-bis(ethyl)- and (propyl)-SPD were nearly as effective as SPD. Apparently, the central amine of the molecule is critical for regulatory function.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Characterization of L1210 cell growth inhibition by the bacterial iron chelators parabactin and compound II.

Microbial siderophores represent a class of iron chelators characterized by their high affinity (i.e., formation constants, greater than 10(40) M) for ferric iron. Previously, we demonstrated that the bacterial siderophores, N-[3-(2,3-dihydroxybenzamido)propyl]-N-[4-(2, 3-dihydroxybenzamino)butryl]-2-(2-hydroxyphenyl) trans-5-methyloxazoline-4-carboxamide (Parabactin) and N1,N8-bis(2,3-dihydroxybenzoyl)spermidine (Compound II), inhibit the growth of L1210 cells and the replication of DNA (but not RNA) viruses at low micromolar concentrations (Biochem. Biophys. Res. Commun., 121: 848-854, 1984). The basis for this antiproliferative effect on L1210 cells has now been investigated further. Onset of growth inhibition induced by 5 microM Parabactin occurs much earlier than with an equimolar concentration of Compound II but, once established by either chelator, inhibition appears to be irreversible. Growth inhibition was fully preventable with exogenous FeCl3 when given at the same time as the chelators. Flow cytometric analysis revealed a G1-S cycle block following treatment for 4 h with either 5 microM Parabactin or 30 microM Compound II. The block was readily reversed with exogenous FeCl3, allowing cells to progress to mid-S phase by 3 h and to G1 again by 9 h. Thereafter, cells accumulated at a second block located at S phase. The treatment conditions required for the initial cell cycle block (at 4 h) were adapted for subsequent studies. Clonogenicity of L1210 cells in soft agar following a 4-h exposure was reduced to 22% of control by 5 microM Parabactin and to 16% by 30 microM Compound II. Neither growth inhibition in suspension culture nor decreased clonogenicity in soft agar could be reversed with exogenous iron, following treatment with the chelators. Both chelators caused an early and significant decrease in [14C]thymidine incorporation over the 4-h period (50% inhibitory concentration at 4 h, 0.4 microM for Parabactin and 6.0 microM for Compound II). [3H]Uridine incorporation was inhibited later than [14C]thymidine and to a much lesser extent, while [3H]leucine incorporation was not significantly affected. Treatment of cells with 5 microM Parabactin or Compound II for 4 h decreased deoxy-adenosine triphosphate pools by 38 and 70%, respectively, and increased deoxythymidine triphosphate pools by 67 and 36%, respectively, suggesting interference with ribonucleotide reductase. Indeed, extracts of cells treated for 4 h with either 5 microM Parabactin or 30 microM Compound II exhibit a 97 to 98% decrease in cytidine-5'-diphosphate reductase activity compared to control, whereas DNA polymerase was elevated slightly.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

Antineoplastic and antiherpetic activity of spermidine catecholamide iron chelators.

A series of iron chelating agents including the bacterial siderophores, parabactin and bis-N1,N8(2,3 dihydroxybenzoyl )spermidine, and four related compounds were synthesized and tested biologically. They were found: (a) to inhibit growth of cultured L1210 leukemia cells at IC50 values of 2-14 microM, (b) to inhibit replication of the DNA virus, herpes simplex type I, in monkey kidney cells at IC50 values of 0.4 microM ( parabactin ) to 55 microM, and (c) to be inactive against the RNA virus, vesicular stomatitis, at concentrations up to 1 mM. All effects were fully preventable by exogenous Fe (III). The activities correlated generally with the iron formation constants (10(36) to 10(48) moles/1) and more specifically with the lipophilicity of the compounds. The data suggest inhibition of DNA (but not RNA) synthesis by interference with the iron-containing enzyme, ribonucleotide reductase.

Animals↗
PubMed1984

Enhancement of 1,3-bis(2-chloroethyl)-1-nitrosourea-induced cytotoxicity and DNA damage by alpha-difluoromethylornithine in L1210 leukemia cells.

Polyamine depletion by pretreatment with alpha-difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase, potentiates the cytotoxicity of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) in L1210 leukemia cells grown in a modified soft agar system. The dose enhancement ratio was 1.97 at a control colony formation level of 5%. The basis for this enhancement was investigated at the level of DNA damage using a modified fluorometric assay to quantitate the production of alkaline-labile strand breaks per relative DNA molecular mass. Pretreatment of cultured L1210 cells for 48 hr with 5 mM DFMO depleted intracellular putrescine and spermidine (but not spermine) pools and resulted in a 2.3-fold increase in BCNU-induced (10 micrograms/ml, 2 hr) DNA strand breaks per relative DNA molecular mass. The inclusion of 10 microM spermidine during the DFMO pretreatment fully prevented growth inhibition and enhancement of BCNU-induced DNA damage while maintaining cellular spermidine pools at control levels. The inclusion of 2 microM putrescine or spermidine also prevented growth inhibition and enhancement of DNA damage while maintaining spermidine pools at only 25 to 35% of control. Thus, the portion of spermidine essential for cell growth appears to be associated with DNA. BCNU itself was found to reduce cellular polyamine levels by causing their leakage from cells. In addition, BCNU was found to react directly with spermidine in a cell-free system, resulting in a major reaction product detectable by high-performance liquid chromatography. While decreased interaction of BCNU with polyamines could account, in part, for enhancement effects of DFMO, it is more probable that alterations in DNA structure secondary to polyamine depletion are responsible for these effects.

Animals↗
PubMed1982

Selectivity of antitemplates as inhibitors of deoxyribonucleic acid polymerases.

DNA polymerase alpha from calf thymus was relatively insensitive to the action of partially thiolated polycytidylic acid (MPC) which had been shown previously to be a potent inhibitor of the corresponding enzyme from regenerating rat liver, competitive with the activated DNA template. In contrast, partially thiolated polyuridylic acid (MPU) strongly inhibited the calf thymus enzyme as well, but showed non-competitive kinetics with respect to the activated DNA template. The much more potent inhibitory activity of MPU compared to MPC was attributed to the less rigid conformation of the former. Methyl substitution on the 5-mercapto groups of MPU substantially decreased but did not abolish its inhibitory activity. MPU was also a potent inhibitor of the herpes virus (HSV-1) induced DNA polymerase which, too, showed little sensitivity toward MPC; in this case, the inhibition by MPU was uncompetitive with respect to the DNA template. In preliminary experiments, MPU showed significant (61%) inhibition of the replication of HSV-1, while MPC was inactive. The results demonstrate that the inhibitory activity of partially thiolated synthetic polynucleotides toward certain DNA polymerases is dependent on the base composition.

Animals↗