PubMed Health⌕ Search

Biomedical subjects

E D Murray

Publications and source records attributed to E D Murray.

At least 19 recordsLinked to original sources
PubMed2000

E-7869 (R-flurbiprofen) inhibits progression of prostate cancer in the TRAMP mouse.

E-7869 (R-flurbiprofen) is a single enantiomer of a racemic nonsteroidal anti-inflammatory drug. E-7869 does not inhibit either cyclooxygenase-1 or cyclooxygenase-2. We used the transgenic adenocarcinoma mouse prostate (TRAMP) mouse, a prostate cancer model, to evaluate the effect of this drug on prostate cancer progression. Sixty 12-week-old male TRAMP mice were placed randomly into five groups. The animals were treated by daily oral gavage with vehicle (1% carboxymethylcellulose) or E-7869 for 18-weeks. During the course of the study, two diets were used. Three groups (vehicle, 15-mg/kg, and 20-mg/kg drug treatments) received a Teklad diet containing 2.4% saturated fat [a high saturated fat (HSF) diet], and two groups (vehicle and 20 mg/kg drug treatment) received an AIN-93G diet containing 1.05% saturated fat [a low saturated fat (LSF) diet]. At necropsy, the urogenital system and periaortic lymph nodes were removed and weighed. The prostate lobes, seminal vesicles, lungs, and periaortic lymph nodes were preserved and sectioned for histological evaluation. The lung and periaortic lymph nodes were graded as to the presence (+) or absence (-) of metastasis; the urogenital tissues were graded on a 1-6 scale for degree of neoplasia/carcinoma. For both diets, the urogenital wet weights and lymph node wet weights in the 20-mg/kg treatment groups were significantly lower as compared to vehicle control groups. In addition, treatment with 20 mg/kg E-7869 in the LSF diet group resulted in a significantly lower primary tumor incidence (P < 0.05) and reduced incidence of metastasis. In this treatment group, the reduced incidence of metastasis was not statistically significant because the LSF diet itself resulted in a remarkably lower incidence of metastasis in the vehicle control group (10% LSF versus 40% HSF). Treatment with 20 mg/kg E-7869 on the HSF diet resulted in a significantly lower incidence of metastasis (P < 0.05) and a reduction in the primary tumor incidence. These results suggest that E-7869 is a promising chemopreventive and treatment for human prostate cancer.

Adenocarcinoma↗
PubMed2000

Treatment and survival study in the C57BL/6J-APC(Min)/+(Min) mouse with R-flurbiprofen.

Our previous studies with the mouse model of familial adenomatous polyposis (FAP), C57BL/6J-APC(Min)/+ or Min mouse, demonstrated the optimal dose for adenoma reduction with R-flurbiprofen was 10 mg/kg/day as an undivided dose. Divided doses exhibited no increased efficaciousness. This study examines 10 mg/kg R-flurbiprofen daily (qd) on survival as well as a second daily (q.o.d.) schedule and compares it with sulindac sulfone. The q.o.d. schedule at 10 mg/kg was equally efficacious as qd treatment at the same dose. For the q.o.d. group, tumor number decreased similarly (p<0.01); while body weight gain (p<0.01), hematocrit and average tumor area (both, p<0.05) were improved compared with qd treatment. Treatment with R-flurbiprofen (10 mg/kg/day) increased survival significantly (p=0.0004, log-rank) compared to vehicle treated animals. Major biological endpoints (hematocrit, weight gain, tumor number, average and total area [99% reduction]) were significantly improved in treated animals (p<0.01). Sulindac sulfone treatment (50 mg/kg/day) of the Min mouse produced no significant biological benefit. The dose schedule study suggests that for tumor reduction it is necessary to attain a threshold drug-level but not necessarily sustain it over 24 hrs (pharmacodynamic t1/2 >> pharmacokinetic t1/2). During the period of administration R-flurbiprofen dramatically prolongs survival for the mouse model of the human disease, FAP.

Adenomatous Polyposis Coli↗
PubMed1998

Mechanism of enhancement of intestinal ulcerogenicity of S-aryl propionic acids by their R-enantiomers in the rat.

We previously observed a marked increase in gastrointestinal toxicity of rac-flurbiprofen compared to the therapeutically equivalent dose of the S enantiomer. This paper quantitates these observations and examines the mechanism by which this paradoxical toxicity occurs. We have evaluated the ulcer scores, mucosal neutrophil infiltration, by immunostaining of CD11/18 antigen, and mucosal neutrophil activity by myeloperoxidase measurement at two dose levels of (R)-, (S)-, and rac-flurbiprofen, administered over 30 days. Dose-response for intestinal ulcer production was observed for rac- and (S)-flurbiprofen; animals given (R)-flurbiprofen exhibited no ulcers. Yet rac-flurbiprofen proved to be twice as ulcerogenic as (S)-flurbiprofen. The mechanism of the exacerbation of gastrointestinal toxicity of (S)-flurbiprofen by the noncyclooxygenase inhibiting (R)-flurbiprofen is believed to be associated with its effect on ICAM-1 up-regulation. This is followed by neutrophil adhesiveness to ICAM-1 via the LFA-1 antigen on its surface and the extravasation of neutrophils into the tissue. We also examined the effect of high dose (R)-flurbiprofen vs vehicle over 15 days in animals in which ulcers had been produced by treatment with (S)-flurbiprofen for the previous 15 days. (R)-flurbiprofen did not sustain induced ulcers. The results of this study suggest that human studies be conducted to determine if enhanced gastrointestinal toxicity occurs in man. This is at issue since rac compounds of this class are available over the counter and others may be introduced.

Animals↗
PubMed1997

R-flurbiprofen chemoprevention and treatment of intestinal adenomas in the APC(Min)/+ mouse model: implications for prophylaxis and treatment of colon cancer.

We used the C57BL/6J-APC(Min)/+ mouse (Min mouse) to evaluate the chemopreventive effects of R-flurbiprofen (R-FB), the noncyclooxygenase-inhibiting enantiomer of FB. Weanling Min mice were administered 6 weeks of oral treatment with R-FB using 2.5-25 mg/kg of R-FB once per day (q.d.), 2.5-10 mg/kg of R-FB twice per day (b.i.d.), and 5 mg/kg of R-FB b.i.d. challenged with a high saturated fat diet. At necropsy we determined tumor and ulcer numbers, tumor size, and plasma levels of R- and S-FB. A linear dose response was observed from 2.5 to 10 mg/kg of R-FB, regardless of whether the drug was administered as a single or divided dose. Reductions in tumor number were significant (P < or = 0.02) for doses of R-FB from 2.5 to 25 mg/kg/day. A dose of 5 mg/kg R-FB b.i.d. was able to overcome the doubling in tumor number associated with the high saturated fat diet. At 20 and 25 mg/kg/day R-FB, we obtained the maximum response with up to 90% inhibition of total tumor number. At these doses, however, there was toxicity and animal deaths. This toxicity was associated with ulceration, presumably resulting from the in vivo epimerization of R- to S-FB that occurs in the mouse. Thus, we evaluated the oral pharmacokinetics of R-FB and its conversion to S-FB in wild-type mice. These kinetics experiments revealed inversion rates of 7.3 and 11.0% for the 2.5 and 10 mg/kg R-FB doses, respectively. S-FB administered alone (0.5 and 2.0 mg/kg q.d.), in doses mimicking the concentrations of S-FB associated with the R to S epimerization of the doses of R-FB used in our experiments, had little or no antitumor efficacy (P > 0.05). Thus, we conclude that R-FB itself, not the S-FB resulting from epimerization in the mouse, inhibits adenoma formation in the Min mouse. In humans, where there is no R to S epimerization, it is possible that larger doses of R-FB can be used without causing cyclooxygenase inhibition and its resulting ulcerogenicity and other side effects. To assess the effect of R-FB on established adenomas, we allowed 40 Min mice to remain untreated until 70 days of age (the time of necropsy in the previous experiments) and then treated them for an additional 42 days with 10 mg/kg R-FB q.d. or 5 mg/kg R-FB b.i.d.. Both drug-treated groups demonstrated tumor numbers significantly less than that of the vehicle control (P < 0.01). Our results suggest that prophylaxis and treatment trials of R-FB should be extended to humans.

Adenoma↗
PubMed1997

Endogenous natriuretic factors 6: the stereochemistry of a natriuretic gamma-tocopherol metabolite LLU-alpha.

2,7,8-Trimethyl-(S)-2-(beta-carboxyethyl)-6-hydroxy chroman (S-LLU-alpha) isolated from human uremic urine is apparently an oxidative side-chain degradation product of gamma-tocopherol. This compound exhibits natriuretic activity in vivo and it appears to mediate the inhibition of the 70 pS K+ channel in the apical membrane of the thick ascending limb of the nephron. The stereochemistry at the C-2 of LLU-alpha has been unequivocally established to be S(+) by X-ray crystallographic analysis of a diastereomeric amide derivative. It was also established that the chroman ring oxidation of S-LLU-alpha proceeded without racemization at C-2. This finding can be extended to nonepimerization at C-2 of alpha-delta tocopherols (Vitamin E) during side-chain oxidation and stereospecificity (retention or inversion) of oxidative opening of the chroman ring. The resolution of the enantiomers of the parent compound and derivatives was accomplished by chiral high-performance liquid chromatography. The stereospecific enzymatic hydrolysis by an array of commercially available enzymes of the racemic methyl ester of LLU-alpha was investigated. The lipase from Humicola languinosa appears to be the best enzyme for resolution by selective hydrolysis of the racemic methyl ester.

Chromans↗
PubMed1997

Endogenous natriuretic factors 7: biospecificity of a natriuretic gamma-tocopherol metabolite LLU-alpha.

The structural elucidation and mechanism of action of a potential component, LLU-alpha, of what is possibly a multifactorial complex known as "natriuretic hormone" was recently reported [Wechter, W.J. et al. (1996a) Proc. Natl. Acad. Sci. U.S.A. 93: 6002-6007]. "Natriuretic hormone," a long-sought factor, is believed to regulate extracellular fluid volume and consequently be pathomimetic for hypertension, cirrhosis, congestive heart failure and other volume expanded states. The studies reported herein further characterize LLU-alpha. The precursor of the endogenous LLU-alpha was demonstrated to be gamma-tocopherol by radiolabeling studies. The pharmacokinetics of infused rac-LLU-alpha proved to be biphasic (half-lives: 12 min and 6 h). Specificity of the inhibition of the 70 pS potassium channel of the thick ascending limb of the loop of Henle was examined with the natural S-enantiomer being the most potent known inhibitor whereas the analogous alpha-tocopherol metabolite, rac-5-Me-LLU-alpha, showed no inhibition. Rac-LLU-alpha does not inhibit two isozymes of the Na+/K+-ATPase. LLU-alpha is natriuretic acting via inhibition of the 70 pS potassium channel and not Na+/K+-ATPase, the assumed mechanism of action of the "natriuretic hormone." LLU-alpha, a metabolite of a vitamin, if it were found to play a role in the regulation of extracellular fluid volume, would be the second example of a vitamin acting as a precursor for a hormone. Of considerable interest is the fact that this manuscript reports the first biological activity of gamma-tocopherol, a member of the vitamin E complex.

Animals↗
PubMed1996

A new endogenous natriuretic factor: LLU-alpha.

For over three decades, renal physiology has sought a putative natriuretic hormone (third factor) that might control the body's pool of extracellular fluid, an important determinant in hypertension, congestive heart failure, and cirrhosis. In our search for this hormone, we have isolated several pure natriuretic factors from human uremic urine that would appear, alone or in combination, to mark a cluster of phenomena previously presumed to be that of a single "natriuretic hormone." This paper reports the purification, chemical structure, and total synthesis of the first of these compounds, LLU-alpha, which proved to be 2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman, presumably a metabolite of gamma-tocopherol. Both natural LLU-alpha and synthetic material are identical (except for optical activity) with respect to structure and biological activity. It appears that the natriuretic activity of LLU-alpha is mediated by inhibition of the 70 pS K+ channel in the apical membrane of the thick ascending limb of the kidney.

Animals↗
PubMed1996

Endogenous natriuretic factors. 5. Synthesis and biological activity of a natriuretic metabolite of diltiazem and its derivatives.

In our search for endogenous natriuretic factors from human uremic urine, we have previously identified a new metabolite of the drug diltiazem (Murray et al. Life Sci. 1995, 57, 2145-2161). The structure of this metabolite, (+)-(2S,3S)-3-hydroxy-5-(2-hydroxyethyl)-2,3-dihydro-2-(4-methoxyphenyl) -1,5-benzothiazepin-4(5H)-one (LLU-beta1; 2), was proved by unequivocal synthesis from a diltiazem synthon. The synthetic material also proved to be natriuretic as had the urinary isolate. Given the acetylation at C-3 in diltiazem, the 3-monoacetate (8) and diacetate (3) derivatives of 2 were prepared. The 4-nor-keto (6) derivative of 2 was also synthesized. Only the parent 2 induced natriuresis over a range of doses without accompanying kaliuretic activity at some doses.

Animals↗
PubMed1996

Antiproliferative effects of the enantiomers of flurbiprofen.

Nonsteroidal antiinflammatory drugs (NSAIDs) are recognized for inhibiting growth of colon tumors in animal models, and for reducing the risk of colon cancer in humans. The mechanisms involved have not been established, but are thought to be related to reduced prostaglandin biosynthesis. The present study investigates the effect of COX-inhibiting and non-COX-inhibiting enantiomers of flurbiprofen on rat colonocyte proliferation. Intestinal ulceration was used as a surrogate indicator of COX inhibition. Sprague Dawley rats were treated orally with 6.3 mg/kg of R- or s-flurbiprofen or vehicle. Colonocyte labeling index and small bowel ulcer index were measured. R-flurbiprofen and S-flurbiprofen significantly reduced colonocyte labeling index, by 34% and 23% respectively, compared with vehicle. R-flurbiprofen caused minimal ulcer formation (4.48 mm2) compared with S-flurbiprofen (94.4 mm2). These findings suggest that R-flurbiprofen-mediated control of colonocyte proliferation is independent of prostaglandin biosynthesis.

Animals↗
PubMed1995

Endogenous natriuretic factors 3: isolation and characterization of human natriuretic factors LLU-alpha, LLU-beta 1, and LLU-gamma.

A low molecular weight endogenous substance believed to be responsible for extracellular fluid homeostasis in mammals has been sought for many years. Our goal is to isolate and structurally characterize this putative "natriuretic hormone." We have developed an assay using the conscious rat to measure prolonged natriuresis (Benaksas et al (1993) Life Sciences, 52, 1045-1054), the activity originally described for this putative substance. Using this assay we have identified a number of natriuretic compounds isolated from human uremic urine. The collected urine is processed by ultrafiltration (< or = 3 kDa), gel filtration chromatography (G-25) and extraction with isopropanol and diethyl ether. The organic soluble material is then subjected to sequential high-performance liquid chromatography. We report here the initial characterization of two pure isolates (LLU-alpha and LLU-gamma) obtained by this method, and the structural elucidation of a third pure compound, LLU-beta 1, a natriuretic and previously unreported metabolite of the drug diltiazem.

Animals↗
PubMed1994

Chiral pharmacokinetics of Rac-flurbiprofen and pharmacodynamics of anabolic bone response in the normal rat.

The route of administration of the NSAID, flurbiprofen (sq vs. po) resulted in positive and negative results respectively with regard to enhanced cancellous and cortical bone accumulation in the immature rat. This pharmacokinetic study was an effort to understand the pharmacodynamic difference between the two routes of administration observed when the same dose range of drug, given as single daily doses, had been employed in both studies. Conventional chiral pharmacokinetics were evaluated in young rats. A significant difference was observed in the Tmax of the active (S)-enantiomer by both administration routes (sq 4 h and po 1 h). The bioavailability, as evaluated by AUCs favored the sq route as expected. The plasma concentrations over 18 h, at steady state, for one po dose group (0.5 mg/kg/day) fell well within the therapeutic window described by the 0.1 and 0.5 mg/kg sq doses which had demonstrated anabolic bone activity. Oral dosing had exhibited no significant bone activity. We conclude that the pharmacodynamic difference between routes of administration cannot be simply explained on a pharmacokinetic basis. Consequently, experiments detailing the pharmacodynamics and pharmacokinetics of single and multiple dose administration of aryl-propionic acids in normal and osteopenic states need further pharmacologic study.

Administration, Oral↗
PubMed1993

Rac-flurbiprofen is more ulcerogenic than its (S)-enantiomer.

The most common, and sometimes life-threatening, side-effects associated with the human use of the analgesic, nonsteroidal antiinflammatory drugs (NSAIDs) are gastrointestinal. These include gastritis, ulceration, and severe bleeding. The aryl propionic acid class of NSAIDs are among the most widely used of these drugs in the world, including rac-ibuprofen, rac-flurbiprofen, and rac-ketoprofen. Marketed as racemates, it was assumed that the "inactive" (R)-enantiomers, having no cyclooxygenase inhibiting effect, also had no toxic effect. In a 30-day dose response study of (S)-, (R)-, and rac-flurbiprofen given daily over a range of doses the (R)-isomer alone proved to be without apparent gastrointestinal (GI) toxicity. On the other hand the racemate proved to be 2 to 4 times as ulcerogenic in enantiomerically equivalent doses as the (S)-enantiomer. These results have significant clinical implications.

Animals↗
PubMed1993

Endogenous natriuretic factors 1: sodium pump inhibition does not correlate with natriuretic or pressor activities from uremic urine.

It is our purpose to isolate and characterize the putative "Natriuretic Hormone", ostensibly responsible for ECF homeostasis, as well as identify endogenous pressors and compounds that induce prolonged natriuresis; we report here our initial progress in this area. Large volumes of pooled urine collected from uremic patients were fractionated, and the resulting isolates were evaluated for in vivo natriuretic and pressor effects and Na+/K(+)-ATPase inhibitory activity in renal cells. The purification steps involved ultrafiltration to obtain materials of less than 3000 da, gel filtration, and sequential reversed-phase high performance liquid chromatography (HPLC). After each HPLC step, the fractions were evaluated for their ability to elicit significant natriuresis and/or influence mean arterial pressure in the normal conscious female rat. Each fraction was also assayed for its ability to inhibit Na+/K(+)-ATPase as determined by the inhibition of 86Rb+ uptake into MDBK renal cells. While several of the fractions elicited profound natriuresis and/or pressor activity and other fractions inhibited Na+/K(+)-ATPase, there was no correlation among the activities in individual fractions. We have concluded that this plethora of bioactivities is responsible for much of the confusion and multiplicity of crude isolates claimed to be the putative hormone. Presently we are attempting to purify each of these activities to chemical homogeneity for structure determination.

Animals↗
PubMed1993

Endogenous natriuretic factors. 2: Characterization of natriuretic and vasopressive substances from human uremic urine.

It is our intention to isolate, purify, and characterize the putative low-molecular-weight "natriuretic hormone" responsible for extracellular fluid (ECF) homeostasis. Toward this end, we are purifying from human uremic urine, and identifying endogenous vasopressor and natriuretic compounds. Bioactive components from large volumes of pooled urine were purified by ultrafiltration (< or = 3 kDa), gel filtration chromatography, and sequential reverse-phase and normal-phase high-performance liquid chromatography (HPLC). After each HPLC step, the fractions were evaluated in vivo, were assayed for inhibition of Na+/K(+)-ATPase-mediated 86Rb+ uptake, and were checked for cross-reactivity with an anti-ouabain antibody. Fractions assayed in vivo were identified that induced natriuresis, altered mean arterial pressure, or increased plasma cyclic-GMP. Also, many fractions inhibited Na+/K(+)-ATPase and/or cross-reacted with anti-ouabain antibody. None of the in vitro assays correlates with natriuretic or pressor effects. This plethora of bioactivities, revealed only with increased sample purity, may account for much of the confusion and multiplicity of crude isolates claimed to be the putative hormone. Presently we are attempting to purify and identify these natriuretic materials. One of these, a 3-substituted indole, has been partially characterized.

Animals↗
PubMed1987

Production of a mouse-human chimeric monoclonal antibody to CD20 with potent Fc-dependent biologic activity.

Mouse monoclonal antibody 2H7 recognizes the CD20 cell surface phosphoprotein that is expressed in normal as well as malignant B cells. CD20 may be a useful target for therapy of B cell lymphomas, since damaged normal B cells can be replaced by their antigen-negative precursors. Monoclonal antibody 2H7 is an IgG2b (kappa) immunoglobulin which cannot mediate antibody-dependent cellular cytotoxicity with human lymphocytes or complement-dependent cytotoxicity with human serum. We have now generated a chimeric 2H7 antibody by substituting the mouse constant domains of 2H7 with the human gamma 1 and kappa domains. This new antibody has the same binding specificities as 2H7 but is highly effective in mediating antibody-dependent cellular cytotoxicity with human effector cells and complement-dependent cytotoxicity with human complement.

Amino Acid Sequence↗
PubMed1987

Protein carboxyl methyltransferase facilitates conversion of atypical L-isoaspartyl peptides to normal L-aspartyl peptides.

Prolonged incubation of L-isoaspartate-containing forms of lactate dehydrogenase (231-242), sperm activating peptide, and adrenocorticotropin (22-27) at 37 degrees C, pH 7.4, with S-adenosyl-L-methionine and protein carboxyl methyltransferase from bovine brain leads to extensive conversion of the atypical isopeptide bond to a normal peptide bond. For the lactate dehydrogenase-related peptide, conversion was 80% complete after 24 h. For the other two peptides, conversion reached a level of approximately 65% after 48 h. The mechanism of conversion involves (i) rapid enzymatic methylation of the alpha-carboxyl of the L-iso-Asp residue; (ii) nonenzymatic demethylation resulting in formation of an L-aspartyl cyclic imide; and (iii) a slow, nonenzymatic hydrolysis of the cyclic imide to form a mixture of 15-25% normal L-Asp peptide and 75-85% L-iso-Asp peptide. The regenerated L-iso-Asp peptide is remethylated and the cycle is repeated. The extent of conversion is limited by a competing side reaction wherein the L-imide slowly racemizes, leading to the formation of mainly D-iso-Asp peptide, which is not a substrate for the methyltransferase. The ability of protein carboxyl methyltransferase to initiate conversion of L-iso-Asp residues to normal L-Asp suggests a possible role for this enzyme in facilitating the repair or degradation of deamidated proteins in vivo.

Amino Acid Sequence↗