A 3-month, randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of a highly optimized, capacitively coupled, pulsed electrical stimulator in patients with osteoarthritis of the knee

OBJECTIVE

To investigate the efficacy and safety of a capacitively coupled, pulsed electrical stimulation device in treating knee osteoarthritis (OA).

DESIGN

Fifty-eight outpatients with moderate to severe OA of the knee entered a 3-month, double-blind, placebo-controlled trial, using either an active or placebo device at home for 6 to 14 h/day. Outcome measures included a patient global evaluation, a patient report of knee pain severity, and the Western Ontario and McMaster Universities (WOMAC) questionnaire.

RESULTS

Active treatment provided superior outcomes between baseline and 3-month follow-up measurements: 50.6% greater improvement than placebo in patient global (P=0.03), 31.2% in patient pain (P=0.04), 25.1% in WOMAC stiffness (P=0.03), 29.5% in WOMAC function (P=0.01), 19.9% in WOMAC pain (P=0.11), and 27% in total WOMAC (P=0.01). The percent of patients who improved by more than 50% was 38.5 active vs 5.3 placebo in patient global (P=0.01), 43.6 vs 15.8 in patient pain (P=0.04), 38.5 vs 10.5 in WOMAC pain (P=0.03), 28.2 vs 5.3 in WOMAC stiffness (P=0.08), 23.1 vs 5.3 in WOMAC function (P=0.14), and 23.1 vs 5.3 in total WOMAC (P=0.14). Twenty-one percent of placebo and 18% of actively treated patients developed a transient rash at the electrode sites. No other adverse device effects were reported.

CONCLUSION

A highly optimized, capacitively coupled, pulsed electrical stimulus device significantly improved symptoms and function in knee OA without causing any serious side effects.

Pharmacogenetic and metabolite measurements are associated with clinical status in patients with rheumatoid arthritis treated with methotrexate: results of a multicentred cross sectional observational study

OBJECTIVE

To investigate the contribution of red blood cell (RBC) methotrexate polyglutamates (MTX PGs), RBC folate polyglutamates (folate PGs), and a pharmacogenetic index to the clinical status of patients with rheumatoid arthritis treated with MTX.

METHODS

226 adult patients treated with weekly MTX for more than 3 months were enrolled at three sites in a multicentred cross sectional observational study. Clinical status was assessed by the number of joint counts, physician's global assessment of disease activity, and a modified Health Assessment Questionnaire (mHAQ). RBC MTX PG and folate PG metabolite levels were measured by high performance liquid chromatography fluorometry and radioassay, respectively. A composite pharmacogenetic index comprising low penetrance genetic polymorphisms in reduced folate carrier (RFC-1 G80A), AICAR transformylase (ATIC C347G), and thymidylate synthase (TSER*2/*3) was calculated. Statistical analyses were by multivariate linear regression with clinical measures as dependent variables and metabolite levels and the pharmacogenetic index as independent variables after adjustment for other covariates.

RESULTS

Multivariate analysis showed that lower RBC MTX PG levels (median 40 nmol/l) and a lower pharmacogenetic index (median 2) were associated with a higher number of joint counts, higher disease activity, and higher mHAQ (p<0.09). Multivariate analysis also established that higher RBC folate PG levels (median 1062 nmol/l) were associated with a higher number of tender and swollen joints after adjustment for RBC MTX PG levels and the pharmacogenetic index (p<0.05).

CONCLUSION

Pharmacogenetic and metabolite measurements may be useful in optimising MTX treatment. Prospective studies are warranted to investigate the predictive value of these markers for MTX efficacy.

Management of respite and personal assistance services in a consumer-directed family support programme

BACKGROUND

The present study explores the management of respite and personal assistance services by families with relatives with developmental disability (DD). It focuses on the control of families over recruiting, hiring, training, scheduling, directing and negotiating wages of the staff they hire to provide services.

METHODS

Surveys from 97 families using paid respite or personal assistance services were used to test associations between: 1) level of control of services and outcome variables; 2) hiring relatives to provide services and outcome variables.

RESULTS

More control by families in the management of their respite/personal assistance services was associated with increased service satisfaction, increased community involvement of individuals with DD and increased employment of mothers. Families tended to hire friends, neighbours, and to a great extent, other family members. Hiring of other relatives to provide services was associated with the increased community involvement of individuals with DD.

CONCLUSIONS

The present study supports the idea that there are benefits for both caregivers and individuals with DD with increased control of respite and personal assistance services. The study also supports benefits associated with hiring relatives and recommends additional research in this area to guide policies.

Design, expression, and characterization of a synthetic human cannabinoid receptor and cannabinoid receptor/ G-protein fusion protein

We report here the synthesis and characterization of two gene constructs designed to facilitate structure/function studies of the human neuronal cannabinoid receptor, CB1. The first gene, which we call shCB1, is a synthetic gene containing unique restriction sites spaced roughly 50-100 bases apart to facilitate rapid mutagenesis and cloning. A nine amino acid epitope tag (from the rhodopsin C-terminus) is also present in the shCB1 C-terminal tail to enable detection and purification using the monoclonal antibody 1D4. We find that that the shCB1 gene can be transiently expressed in COS cells with yield of approximately 10-15 micro g receptor per 15 cm plate and is wild type like in its ability to bind cannabinoid ligands. Our confocal microscopy studies indicate shCB1 targets to the membrane of HEK293 cells and is internalized in response to agonist. To facilitate functional studies, we also made a chimera in which the C-terminus of shCB1 was fused with the N-terminus of a G-protein alpha subunit, Galphai. The shCB1/Galphai chimera shows agonist stimulated GTPgammaS binding, and thus provides a simplified way to measure agonist induced CB1 activation. Taken together, the shCB1 and shCB1/Galphai gene constructs provide useful tools for biochemical and biophysical examinations of CB1 structure, activation and attenuation.

Safety assessment of allylalkoxybenzene derivatives used as flavouring substances - methyl eugenol and estragole

This publication is the seventh in a series of safety evaluations performed by the Expert Panel of the Flavor and Extract Manufacturers' Association (FEMA). In 1993, the Panel initiated a comprehensive program to re-evaluate the safety of more than 1700 GRAS flavouring substances under conditions of intended use. In this review, scientific data relevant to the safety evaluation of the allylalkoxybenzene derivatives methyl eugenol and estragole is critically evaluated by the FEMA Expert Panel. The hazard determination uses a mechanism-based approach in which production of the hepatotoxic sulfate conjugate of the 1'-hydroxy metabolite is used to interpret the pathological changes observed in different species of laboratory rodents in chronic and subchronic studies. In the risk evaluation, the effect of dose and metabolic activation on the production of the 1'-hydroxy metabolite in humans and laboratory animals is compared to assess the risk to humans from use of methyl eugenol and estragole as naturally occurring components of a traditional diet and as added flavouring substances. Both the qualitative and quantitative aspects of the molecular disposition of methyl eugenol and estragole and their associated toxicological sequelae have been relatively well defined from mammalian studies. Several studies have clearly established that the profiles of metabolism, metabolic activation, and covalent binding are dose dependent and that the relative importance diminishes markedly at low levels of exposure (i.e. these events are not linear with respect to dose). In particular, rodent studies show that these events are minimal probably in the dose range of 1-10 mg/kg body weight, which is approximately 100-1000 times the anticipated human exposure to these substances. For these reasons it is concluded that present exposure to methyl eugenol and estragole resulting from consumption of food, mainly spices and added as such, does not pose a significant cancer risk. Nevertheless, further studies are needed to define both the nature and implications of the dose-response curve in rats at low levels of exposure to methyl eugenol and estragole.

Mechanisms of hormonal carcinogenesis in the p53+/- hemizygous knockout mouse: studies with diethylstilbestrol

The 2-year rodent bioassay has long had a central role in determining whether a compound is carcinogenic. It has recently been suggested that the use of 6-month studies in transgenic mice could reduce costs and animal numbers, without impairing the validity of cancer risk assessment. The p53+/- hemizygous knockout mouse model is phenotypically stable and develops tumors during the 6-month study period only in response to chemical and physical stimuli, showing a high concordance with genotoxic rodent carcinogens. We treated p53+/- mice and wild-type parent strain (C57BL/6J) animals with diethylstilbestrol (DES). 500 micromol/kg i.p. for 4 days. Following sacrifice, DNA was extracted from various tissues and adducts measured by a modified monophosphate version of the 32P-postlabelling assay. Major DES adducts were detected in the liver DNA of DES-treated wild-type mice at a level of 118.7+/-17.0 (mean +/- SD relative adduct level [RAL]/10(10) nucleotides) compared with 207.7+/-36.4 in p53+/- mice. No such adducts were detected in vehicle-treated animals. Total adduct levels, including endogenous I-compound adducts, in wild-type mice were 192.4+/-17.5 and 311.5+/-58.6 in p53+/- animals. These data support the hypothesis that deficient p53-dependent global genomic repair of DES adducts in p53+/- mice may result in the persistence of exogenous and endogenous DNA adducts that could contribute to earlier carcinogenicity in this model. We also prepared hepatic microsomes from male and female p53+/- and wild-type mice exposed to DES or vehicle. Western blot analysis demonstrated modestly higher basal levels of various cytochrome P450 (CYP) enzymes in the untreated p53+/- mice compared to the wild-type mice. Furthermore, P450 levels were higher in female DES-treated p53+/- mice compared to treated wild-type mice. For the p53+/- knockout mice to be used with contidence in drug safety studies, a further understanding of the metabolic capacity of these animals is needed.

Two-year, blinded, randomized, controlled trial of treatment of active rheumatoid arthritis with leflunomide compared with methotrexate. Utilization of Leflunomide in the Treatment of Rheumatoid Arthritis Trial Investigator Group

OBJECTIVE

Three 6-12-month, double-blind, randomized, controlled trials have shown leflunomide (LEF; 20 mg/day, loading dose 100 mg x 3 days) to be effective and safe for the treatment of rheumatoid arthritis (RA). This analysis of the North American trial assessed whether the clinical benefit evident at month 12 was sustained over 24 months of treatment with LEF as compared with the efficacy and safety of methotrexate (MTX), an equivalent disease-modifying antirheumatic drug, at 24 months.

METHODS

The year-2 cohort, comprising patients continuing into the second year of treatment with > or = 1 dose of study medication and > or = 1 followup visit after week 52, consisted of 235 patients (LEF n = 98; placebo n = 36; MTX n = 101). The mean (+/- SD) maintenance dose of LEF was 19.6 +/- 1.99 mg/day in year 2 and that of MTX was 12.6 +/- 4.69 mg/week. Statistical analyses used an intent-to-treat (ITT) approach. Statistical comparisons of the active treatments only were prospectively defined in the protocol.

RESULTS

In total, 85% and 79% of LEF and MTX patients, respectively, who entered year 2 completed 24 months of treatment. From month 12 to month 24, the American College of Rheumatology improvement response rates of > or = 20% (LEF 79% versus MTX 67%; P = 0.049), > or = 50% (LEF 56% versus MTX 43%; P = 0.053), and > or = 70% (LEF 26% versus MTX 20%; P = 0.361) were sustained in both of the active treatment groups. The mean change in total Sharp radiologic damage scores at year 2 compared with year 1 and baseline (LEF 1.6 versus MTX 1.2) showed statistically equivalent sustained retardation of radiographic progression in the active treatment groups. Maximal improvements evident at 6 months in the Health Assessment Questionnaire (HAQ) disability index (HAQ DI) and the physical component score of the Medical Outcomes Survey 36-item short form were sustained over 12 months and 24 months; improvement in the HAQ DI with LEF4(-0.60) was statistically significantly superior to that with MTX (-0.37) at 24 months (P = 0.005). Over 24 months in the ITT cohort, serious treatment-related adverse events were reported in 1.6% of the LEF-treated patients and 3.7% of the MTX-treated patients. Frequently reported adverse events included upper respiratory tract infections, diarrhea, nausea and vomiting, rash, reversible alopecia, and transient liver enzyme elevations.

CONCLUSION

The safety and efficacy of LEF and MTX were maintained over the second year of this 2-year trial. Both active treatments retarded radiographic progression over 24 months. LEF was statistically significantly superior to MTX in improving physical function as measured by the HAQ DI over 24 months of treatment. Results indicate that LEF is a safe and effective initial treatment for active RA, with clinical benefit sustained over 2 years of treatment without evidence of new or increased toxicity.

The utility of panoramic imaging of the temporomandibular joint in patients with temporomandibular disorders

OBJECTIVE

The objective of this study was to evaluate the utility of panoramic imaging in assessment of patients with temporomandibular disorders (TMDs).

STUDY DESIGN

Fifty-five consecutive patients referred for diagnosis and management of facial pain and jaw dysfunction were included. A single examiner completed the history and clinical examination on all patients. All patients received panoramic imaging. On the basis of clinical and radiographic findings, a subset of patients received advanced imaging modalities. The panoramic radiographs were interpreted by 2 examiners; if any disagreement was noted, a third examiner interpreted the radiographs.

RESULTS

Seventy-five percent of the patients had complaints of facial pain, and 75% exhibited tenderness in masticatory muscles. Tenderness was present in TM joint regions in 62%. Altered bony anatomy was seen in 43.6% of panoramic radiographs. Panoramic imaging did not lead to changes in clinical diagnosis in any of the patients seen, although the findings on the radiographs did lead to requests for additional imaging studies in 3 cases, one of which was later referred for surgical intervention because of radiographic findings.

CONCLUSION

Clinical findings may be of greater relevance leading to the diagnoses associated with TMD and to determination of the need for additional imaging rather than the use of panoramic imaging in all patients with facial pain and TMD.

Use and efficacy of tuberculosis infection control practices at hospitals with previous outbreaks of multidrug-resistant tuberculosis

OBJECTIVE

To evaluate the implementation and efficacy of selected Centers for Disease Control and Prevention guidelines for preventing spread of Mycobacterium tuberculosis.

DESIGN

Analysis of prospective observational data.

SETTING

Two medical centers where outbreaks of multidrug-resistant tuberculosis (TB) had occurred.

PARTICIPANTS

All hospital inpatients who had active TB or who were placed in TB isolation and healthcare workers who were assigned to selected wards on which TB patients were treated.

METHODS

During 1995 to 1997, study personnel prospectively recorded information on patients who had TB or were in TB isolation, performed observations of TB isolation rooms, and recorded tuberculin skin-test results of healthcare workers. Genetic typing of M tuberculosis isolates was performed by restriction fragment-length polymorphism analysis.

RESULTS

We found that only 8.6% of patients placed in TB isolation proved to have TB; yet, 19% of patients with pulmonary TB were not isolated on the first day of hospital admission. Specimens were ordered for acid-fast bacillus smear and results received promptly, and most TB isolation rooms were under negative pressure. Among persons entering TB isolation rooms, 44.2% to 97.1% used an appropriate (particulate, high-efficiency particulate air or N95) respirator, depending on the hospital and year; others entering the rooms used a surgical mask or nothing. We did not find evidence of transmission of TB among healthcare workers (based on tuberculin skin-test results) or patients (based on epidemiological investigation and genetic typing).

CONCLUSIONS

We found problems in implementation of some TB infection control measures, but no evidence of healthcare-associated transmission, possibly in part because of limitations in the number of patients and workers studied. Similar evaluations should be performed at hospitals treating TB patients to find inadequacies and guide improvements in infection control.

Analysis of a natural immune response against tumor antigens in a melanoma survivor: lessons applicable to clinical trial evaluations

The long-term survival of some patients with metastatic melanoma may be attributable in part to cellular immune responses to melanoma antigens. However, little is known about the level of CTL reactivity in vivo that is required for immunological control of tumor progression. In the present report, T-cell responses were evaluated with lymphocytes obtained from tumor-involved nodes and peripheral blood of a long-term melanoma survivor. Using an ELISPOT assay, naturally occurring functional T cells, which recognize the peptide ALLAVGATK (gp100(17-25)) plus two other HLA-A3 restricted peptides, were detected in a tumor-involved lymph node. The ALLAVGATK-reactive T cells were also evaluated by MHC-tetramers staining and were found to be CD8+ CD45RO+ L-selectin(-) CD11a+, suggesting that they are antigen experienced and have a memory phenotype. Unstimulated peripheral blood lymphocytes from the same patient demonstrated no detectable T-cell responses; however, a single stimulation with ALLAVGATK peptide in vitro resulted in a dramatic expansion of peptide-reactive CTLs. This patient, with evidence of tumor-reactive CTLs targeted to several tumor antigens in a tumor-involved lymph node and with evidence of a circulating memory T-cell response, has remained disease-free for 6 years, despite prior bulky nodal metastasis. In contrast, three HLA-A3+ patients with rapidly progressive metastatic melanoma had no detectable T-cell response in tumor-involved nodes or peripheral blood lymphocytes, even after peptide stimulation ex vivo. The presented data are consistent with a systemic polyvalent immune response against tumor in this long-term survivor. These data provide an estimate of the level of CTL response that may be associated with protection from tumor recurrence.

Results of a phase-I/II randomized, masked, placebo-controlled trial of recombinant human interleukin-11 (rhIL-11) in the treatment of subjects with active rheumatoid arthritis

Interleukin-11 (IL-11) is a pleiotropic cytokine that regulates the growth and development of hematopoietic stem cells and decreases the proinflammatory mediators of cytokine and nitric oxide production. In animal models of arthritis, treatment with recombinant human IL-11 (rhIL-11) reduces both the level of synovitis and the histologic lesion scores in the joints. The goal of this phase-I/II study in adults with rheumatoid arthritis (RA) was to evaluate the safety and clinical activity of different doses and schedules of rhIL-11 in patients with active RA for whom treatment with at least one disease-modifying antirheumatic drug had failed. This was a multicenter, randomized, placebo-controlled trial that evaluated the safety and tolerability of rhIL-11 in 91 patients with active RA. rhIL-11 was administered subcutaneously; patients were randomized into one of five treatment groups (ratio of rhIL-11 to placebo, 4:1). Patients were treated for 12 weeks with either 2.5 or 7.5 microg/kg of rhIL-11 or placebo twice per week or 5 or 15 microg/kg of rhIL-11 or placebo once per week. The status of each subject's disease activity in accordance with the American College of Rheumatology (ACR) criteria was assessed before, during, and after completion of administration of the study drug. Administration of rhIL-11 was well tolerated at all doses and schedules. The most frequent adverse event was a reaction at the injection site. The data suggest a statistically significant reduction in the number of tender joints (P < 0.008) at the 15 microg/kg once-weekly dose schedule but showed no overall significant benefit at the ACR criterion of a 20% response. The trial showed rhIL-11 to be safe and well tolerated at a variety of doses and schedules over a 12-week treatment period in patients with active RA. The only adverse event clearly associated with rhIL-11 administration was reaction at the injection site.

Safety and efficacy of meloxicam in the treatment of osteoarthritis: a 12-week, double-blind, multiple-dose, placebo-controlled trial. The Meloxicam Osteoarthritis Investigators

BACKGROUND

Meloxicam (Mobic; Boehringer Ingelheim, Ridgefield, Conn) is an enolic acid derivative of the oxicam group of nonsteroidal anti-inflammatory drugs (NSAIDs) whose mechanism of action may be related to prostaglandin (cyclooxygenase) synthetase inhibition. In previous studies, meloxicam has been found to be safe and effective in the treatment of osteoarthritis (OA) at doses of 7.5 to 15 mg daily. To evaluate a lower dose and a different patient population, we evaluated the efficacy and safety of 3 doses of meloxicam vs placebo and diclofenac for the treatment of OA among patients with symptom exacerbations.

METHODS

In this double-blind, double-dummy, parallel-group, multicenter study, 774 patients with confirmed OA of the hip or knee and a flare were randomized and treated with daily oral administration of meloxicam tablets (at dosages of 3.75, 7.5, or 15 mg/d), diclofenac (100 mg [50 mg twice daily]), or placebo. Treatment was for 12 weeks, with regular assessments for drug safety and efficacy. Safety was assessed by evaluation of adverse events, vital signs, and laboratory data. Primary efficacy variables included the Western Ontario and McMaster University Osteoarthritis (WOMAC) index, the patient's overall assessment of pain, and the patient's and investigator's overall assessment of disease activity.

RESULTS

The incidence of all adverse events was lower at each dosage of meloxicam than for diclofenac but greater than for placebo. However, the incidence of gastrointestinal adverse events and dropout rates because of such events was the same for meloxicam as for placebo and lower than for diclofenac. Meloxicam, at 7.5 and 15 mg/d, and diclofenac were statistically significantly more effective than placebo for all end points, while the 3.75-mg/d dosage of meloxicam did not always reach statistical significance for all end points. Efficacy was evident after 2 weeks of treatment, improved with increasing doses, and was maintained until the end of the trial.

CONCLUSIONS

Meloxicam is a safe and effective medication for the symptomatic treatment of OA. The data support consideration of 7.5 to 15 mg of meloxicam once daily to treat the pain and stiffness of OA, with gastrointestinal tolerability comparable to that of placebo. Arch Intern Med. 2000;160:2947-2954

Pharmacokinetics and disposition of the novel dopamine agonist Z-7760 in rat after intravenous and oral administration

1. Z-7760 (S(-)-N-[N-2-phenylethyl)-6-hexylamino]-N-propyl-5,6-dihydroxy-1,2,3,4-tetrahydro-2-naphthylamine dihydrobromide) is a potent dopamine D-1 and D-2 agonist synthesized during a search for agents to treat heart failure. Reported is the fate of the drug in rat. 2. 3H-Z-7760 was administered p.o. and i.v. to male Sprague-Dawley rats (0.4 mg and 400 microCi/kg in 0.1% ascorbic acid) and venous blood samples collected at intervals up to 48 h. Comparison of the AUC for total 3H showed that 37% of an oral dose of Z-7760 was absorbed. The percentage plasma 3H present as the parent compound fell from 82% 30 min after i.v. dosing to 12% after 24 h. After oral dosing, the fraction of plasma 3H present as unchanged Z-7760 was < 5% and this was essentially unaltered throughout the study. The long terminal elimination phase evident from 6 h was notable after both routes of administration. 3. The bile duct-cannulated rat was given 3H-Z-7760 p.o. (0.4 mg and 40 microCi/kg) and bile was collected for up to 22 h. Biliary excretion accounted for 30% of the dose. No parent compound was detected in the bile. 4. In further studies, other rats were dosed p.o. or i.v. with 3H-Z-7760 (0.4 mg and 400 microCi/kg) and urine and faeces were collected daily for 3 days. The major route of excretion was the faeces with 94-97% 3H recovered after oral and 70-73% after i.v. dosing. A further 4-7% was recovered in the urine after oral and 12-13% after i.v. dosing. 5. After oral administration of Z-7760 (100 mg/kg, 40 microCi/kg) to rats, the major metabolites in the urine were identified as the 5-O-methyl and glucuronic acid conjugates of Z-7760 by LC and MS. The glucuronide was only seen in urine after oral administration but 5-O-methyl-Z-7760 was present in urine and faeces after both routes of administration. 6. The low bioavailability of Z-7760 is the consequence of its poor absorption from the gastrointestinal tract as well as extensive first-pass metabolism that further reduces systemic blood concentrations after oral administration.

Estimating cancer risk from outdoor concentrations of hazardous air pollutants in 1990

A public health concern regarding hazardous air pollutants (HAPs) is their potential to cause cancer. It has been difficult to assess potential cancer risks from HAPs, due primarily to lack of ambient concentration data for the general population. The Environmental Protection Agency's Cumulative Exposure Project modeled 1990 outdoor concentrations of HAPs across the United States, which were combined with inhalation unit risk estimates to estimate the potential increase in excess cancer risk for individual carcinogenic HAPs. These were summed to provide an estimate of cancer risk from multiple HAPs. The analysis estimates a median excess cancer risk of 18 lifetime cancer cases per 100,000 people for all HAP concentrations. About 75% of estimated cancer risk was attributable to exposure to polycyclic organic matter, 1,3-butadiene, formaldehyde, benzene, and chromium. Consideration of some specific uncertainties, including underestimation of ambient concentrations, combining upper 95% confidence bound potency estimates, and changes to potency estimates, found that cancer risk may be underestimated by 15% or overestimated by 40-50%. Other unanalyzed uncertainties could make these under- or overestimates larger. This analysis used 1990 estimates of concentrations and can be used to track progress toward reducing cancer risk to the general population.

Association of SWAP-70 with the B cell antigen receptor complex

SWAP-70 is a component of an enzyme complex that recombines Ig switch regions in vitro. We report here the cloning of the human cDNA and its B lymphocyte-specific expression. Although its sequence contains three nuclear localization signals, in small resting B cells, SWAP-70 is mainly found in the cytoplasm. On stimulation, SWAP-70 translocates to the nucleus. In activated, class-switching B cell cultures, it is associated with membrane IgG, but not IgM. The membrane Ig association requires a functional pleckstrin homology domain and is controlled by the C terminus. We suggest that SWAP-70 is involved not only in nuclear events but also in signaling in B cell activation.

Treatment of active rheumatoid arthritis with leflunomide compared with placebo and methotrexate. Leflunomide Rheumatoid Arthritis Investigators Group

CONTEXT

Leflunomide is a reversible inhibitor of de novo pyrimidine synthesis shown to be effective in a phase 2 trial in 402 patients with active rheumatoid arthritis (RA).

OBJECTIVE

To compare the efficacy and safety of leflunomide treatment with placebo and methotrexate treatment in patients with active RA.

DESIGN

Randomized, double-blind, placebo, and active-controlled 12-month study.

SETTING

Forty-seven university and private rheumatology practices in the United States and Canada.

PATIENTS

Diagnosis of RA by the American College of Rheumatology (ACR) criteria for duration of 6 months or longer and no previous methotrexate treatment.

INTERVENTION

Leflunomide treatment (20 mg/d), placebo, or methotrexate treatment (7.5-15 mg/wk).

MAIN OUTCOME MEASURES

American College of Rheumatology success rate (completed 52 weeks of treatment and met the ACR > or = 20% response criteria), disease progression as assessed by x-ray films, and improvement in function and health-related quality of life using the intent-to-treat population.

RESULTS

The 482 patients studied were predominantly women (mean age, 54 years; mean disease duration, 6.7 years) for whom a mean of 0.8 disease-modifying antirheumatic drugs had failed. The ACR response and success rates for patients receiving leflunomide treatment (52% and 41%, respectively) and methotrexate treatment (46% and 35%, respectively) were significantly higher than those for patients receiving placebo (26% and 19%, respectively) (P<.001), and they were statistically equivalent, with mean time to initial response at 8.4 weeks for patients receiving leflunomide vs 9.5 weeks for patients receiving methotrexate therapy. X-ray analyses demonstrated less disease progression with leflunomide (P=.001) and methotrexate (P = .02) therapy than with placebo. Leflunomide and methotrexate treatment improved measures of physical function and health-related quality of life significantly more than placebo (P<.001 and P<.05, respectively). Common adverse events for patients receiving leflunomide treatment included gastrointestinal complaints, skin rash, and reversible alopecia. Asymptomatic transaminase elevations resulted in treatment discontinuations for 7.1% of patients receiving leflunomide therapy, 1.7% of patients receiving placebo, and 3.3% of patients receiving methotrexate therapy.

CONCLUSIONS

Clinical responses following administration of leflunomide, a new therapeutic agent for the treatment of RA, were statistically superior to those with placebo and equivalent to those with methotrexate treatment. Both active treatments improved signs and symptoms of active RA, delayed disease progression as demonstrated by x-ray films, and improved function and health-related quality of life.

A pilot study using a staph protein A column (Prosorba) to treat refractory rheumatoid arthritis

OBJECTIVE

To assess the safety and effectiveness of extracorporeal treatments with protein A (Prosorba) columns in the treatment of patients with severe refractory rheumatoid arthritis (RA) in an open label pilot study.

METHODS

Fifteen patients with RA who had failed to respond to 2 or more disease modifying antirheumatic drugs were "washed out" for 1-3 months before enrollment into this 6 month pilot study. The treatment schedule called for patients to receive apheresis treatments across staphylococcal protein A columns once a week for 12 weeks. Clinical evaluations of RA activity, defined by Paulus criteria, were conducted at study enrollment (baseline) and monthly throughout the treatment phase. In addition, examinations were conducted at 2, 4, 8, and 12 weeks after the last treatment. Fourteen patients received all 12 scheduled treatments, while one patient received only 10 treatments due to complications secondary to pneumonia.

RESULTS

Using Paulus 50% criteria, 9 of 15 (60%) patients were improved at the 4th month, and one more fulfilled >20% Paulus criteria (7%) in the 5th month after starting therapy. The study group reported an average of 2.47 adverse effects per treatment, of which the most common were joint pain and swelling and fatigue of short duration (arthritic flare).

CONCLUSION

The adverse effects associated with this apheresis based treatment proved to be manageable and of short duration and resolved without sequelae. The results suggest that extracorporeal protein A therapy may have a role in the management of refractory RA, and encouraged the initiation of a larger, blinded, controlled clinical trial.

Comparison of the upper gastrointestinal safety of Arthrotec 75 and nabumetone in osteoarthritis patients at high risk for developing nonsteroidal anti-inflammatory drug-induced gastrointestinal ulcers

A 6-week, multicenter, double-masked, placebo-controlled, parallel-group study compared the upper gastrointestinal (UGI) safety of Arthrotec 75 (diclofenac sodium 75 mg-misoprostol 200 microg; G.D. Searle & Co., Skokie, Illinois) administered twice daily with that of nabumetone 1500 mg administered once daily in 1203 patients with symptomatic osteoarthritis (OA) of the hip or knee. All patients had a documented clinical history of endoscopically confirmed gastric, pyloric-channel, or duodenal ulcer or > or = 10 erosions in the stomach or duodenum. UGI endoscopy was performed at baseline and again at week 6 or early withdrawal. Treatment with Arthrotec 75 resulted in a significantly lower combined incidence of endoscopically confirmed gastric and duodenal ulcers compared with nabumetone (4% vs 11%), and its rate of endoscopically confirmed ulceration was equivalent to that of placebo. The incidence of gastric ulcers alone was also significantly lower with Arthrotec 75 than with nabumetone (1% vs 9%). The incidence of duodenal ulcer with Arthrotec 75 was not significantly different from that with nabumetone (4% vs 3%). Types of adverse events were similar for all treatment groups, with GI adverse events predominating. Arthrotec 75 was well tolerated by the majority of patients. The results of this study demonstrate that Arthrotec 75 has a superior UGI safety profile, causing significantly fewer UGI ulcers, in comparison with nabumetone in patients with symptomatic OA and a documented history of ulcers or > or = 10 erosions.

Sexual regimes and sexual networking: the risk of an HIV/AIDS epidemic in Bangladesh

Bangladesh adjoins the Asian region with the severest AIDS epidemic and has common borders with two of the most affected areas, the Indian Hill States and northern Burma. There has been disagreement about the danger to Bangladesh, one view citing the likelihood of transmission from neighbouring infected populations and the other claiming that the country's predominantly Muslim culture protects it. This paper reports on a 1995-1997 research project. Preliminary research was carried out in Dhaka in 1995-1996 which suggested that the poor squatter areas might well sustain an epidemic. The experience also showed that more accurate measures of sexual networking could be obtained from males than females. The 1997 field research reported here investigated 983 males, 52% single and 48% married in Chittagong city and two more rural areas of Chittagong Division in southeast Bangladesh. It was found that around half of all males and probably a somewhat lower proportion of females, experience premarital sexual relations, with males having a lower level of extramarital than premarital relations. The factor heightening Bangladesh's risk of an epidemic is that one-quarter of single males and a significant but lower level of married males have had relations with prostitutes. This is one explanation for quite high levels of STDs in Bangladesh. The factors restricting the chances of a major national epidemic are the small number of premarital sexual episodes per person and the low level of intravenous drug use.

Dose-loading with hydroxychloroquine improves the rate of response in early, active rheumatoid arthritis: a randomized, double-blind six-week trial with eighteen-week extension

OBJECTIVE

To investigate the usefulness of hydroxychloroquine (HCQ) dose-loading to increase the percentage of responders or rate of response in treating rheumatoid arthritis (RA).

METHODS

Two hundred twelve patients with early RA (mean duration 1.5 years) were enrolled in a 24-week trial. Patients were stabilized with 1,000 mg naproxen/day and then began a 6-week, double-blind trial comparing treatment with HCQ at 400 mg/day (n = 71), 800 mg/day (n = 71), and 1,200 mg/day (n = 66), followed by 18 weeks of open-label HCQ treatment at 400 mg/day.

RESULTS

All patients had mild, active disease at the time of initiation of HCQ treatment (31-43% rheumatoid factor positive; no previous disease-modifying antirheumatic drugs; mean swollen joint count 8.6-10.4). Based on the Paulus criteria, response during the 6-week double-blind portion of the study was 47.97%, 57.7%, and 63.6% in the 400 mg/day, 800 mg/day, and 1,200 mg/day groups, respectively (P = 0.052). Discontinuations for adverse events were dose related (3 in the 400 mg/day group, 5 in the 800 mg/day group, 6 in the 1,200 mg/day group). Most involved the gastrointestinal (GI) system, with the background naproxen treatment possibly contributing. Ocular abnormalities occurred in 17 of 212 patients (8%) but were not dose related.

CONCLUSION

Dose-loading with HCQ increased the degree of response at 6 weeks in this group of patients with early, predominantly seronegative RA. Adverse GI events were dose related, while adverse ocular events were not.

Dose-loading with hydroxychloroquine improves the rate of response in early, active rheumatoid arthritis: a randomized, double-blind six-week trial with eighteen-week extension

OBJECTIVE

To investigate the usefulness of hydroxychloroquine (HCQ) dose-loading to increase the percentage of responders or rate of response in treating rheumatoid arthritis (RA).

METHODS

Two hundred twelve patients with early RA (mean duration 1.5 years) were enrolled in a 24-week trial. Patients were stabilized with 1,000 mg naproxen/day and then began a 6-week, double-blind trial comparing treatment with HCQ at 400 mg/day (n = 71), 800 mg/day (n = 71), and 1,200 mg/day (n = 66), followed by 18 weeks of open-label HCQ treatment at 400 mg/day.

RESULTS

All patients had mild, active disease at the time of initiation of HCQ treatment (31-43% rheumatoid factor positive; no previous disease-modifying antirheumatic drugs; mean swollen joint count 8.6-10.4). Based on the Paulus criteria, response during the 6-week double-blind portion of the study was 47.97%, 57.7%, and 63.6% in the 400 mg/day, 800 mg/day, and 1,200 mg/day groups, respectively (P = 0.052). Discontinuations for adverse events were dose related (3 in the 400 mg/day group, 5 in the 800 mg/day group, 6 in the 1,200 mg/day group). Most involved the gastrointestinal (GI) system, with the background naproxen treatment possibly contributing. Ocular abnormalities occurred in 17 of 212 patients (8%) but were not dose related.

CONCLUSION

Dose-loading with HCQ increased the degree of response at 6 weeks in this group of patients with early, predominantly seronegative RA. Adverse GI events were dose related, while adverse ocular events were not.

Enantioselective biotransformation of aryl-isopropyl, -isopropenyl, and -propenyl groups by the rabbit or by the rat

Thirteen kinds of aromatic compounds (Alkyl- and alkenyl-) were administered to rabbits and the chiralities of their optical active metabolite were determined by the synthesis of the enantiomers or their derivatives. This work has revealed many examples of enantioselective biotransformations and chiral inversion in the rabbits and mechanisms for this inversion have been proposed. The enantioselective hydration of transanethole epoxide was also examined in vitro in rat liver microsomes and possible mechanisms of this process are also discussed.

Preoperative risk models for minimally invasive coronary bypass: a preliminary study

OBJECTIVE

Available risk assessment models are designed for standard coronary artery bypass grafting. We hypothesized that minimally invasive coronary bypass could improve on predicted outcome in extremely high-risk patients (Parsonnet score > 20%) by the current risk models.

METHODS

From September 1996 to September 1997, 27 consecutive extremely high-risk patients underwent minimally invasive coronary bypass. Seventeen patients were male; age was 73 +/- 12 years, and 63% of patients were older than 75 years. Left ventricular ejection fraction was 33.7% +/- 15% and 63% had an ejection fraction of less than 35%. The predicted 30-day mortality according to the System 97 model was 25.6% +/- 11.3%. The Parsonnet risk score was 36.2% +/- 11%; the predicted length of stay in the hospital was 15.3 +/- 3 days. The predicted risk of stroke according to the Multicenter Perioperative Stroke Risk Index was 22.3% +/- 11.7%.

RESULTS

Minimally invasive coronary bypass was isolated in 20 patients and integrated with angioplasty and stenting in 7 patients. The observed 30-day mortality was 0% (P < .01 vs predicted): at an average follow-up of 10.8 +/- 4.1 months, 26 patients (96.3%) are alive without angina; one patient with acquired immunodeficiency syndrome died on postoperative day 40 of acute pancreatitis. No patient had a stroke or neurologic deficit (P < .01 vs predicted). Patency of internal thoracic artery anastomosis was confirmed by angiography in all 27 patients. No patient required reoperation. Eighteen patients (67%) were extubated in the operating room. The observed length of hospital stay after minimally invasive coronary bypass was 3.8 +/- 2.6 days (P < .01 vs predicted).

CONCLUSION

On the basis of our results on a relatively small series of patients, we suggest that risk models geared for standard coronary bypass grafting may not be appropriate for minimally invasive coronary bypass.

The application of capillary gas chromatography-selective ion mass spectrometry for the separation, identification and quantification of phenolic bupivacaine metabolites from human urine

A capillary gas chromatographic method has been developed and validated for the separation of phenolic metabolites from human urine following the intravenous infusion of racemic bupivacaine, with subsequent formal identification and quantification by on-line mass spectrometry.

Immunochemical identification of hepatic protein adducts derived from estragole

Hepatic protein adducts derived from the allylbenzene food flavor estragole, which is hepatocarcinogenic when given to rodents at high doses, have been identified using immunochemical approaches. Male Fischer 344 rats were given estragole orally and hepatic protein adducts were detected by immunoblotting, using antisera raised by immunizing rabbits with 4-methoxycinnamic acid-modified rabbit serum albumin. A major 155-kDa adduct was expressed in livers of animals that had been treated with estragole at 100, 300, or 500 mg/kg. Levels of expression of the adduct increased disproportionately with respect to dose, and other adducts (170, 100, 44, and 35 kDa) were detected also in the high-dose group. Rats given estragole for 5 days, at 300 mg/kg/day, expressed predominantly 155- and 44-kDa adducts. The 155-, 100-, 44-, and 35-kDa adducts were detected in greatest abundance in liver microsomal fractions, while the 170-kDa adduct was most abundant in the nuclear fraction. Interestingly, whereas the 170-, 155-, 100-, and 35-kDa adducts were detected in cytosolic fractions, relatively low levels of the 44-kDa adduct were detected in nuclear fractions but not in cytosolic fractions. The various adducts were solubilized when microsomal fractions were extracted with sodium carbonate and were digested by trypsin. This implies that the target proteins are peripheral membrane proteins bound to the outer surface of microsomal membranes. Experiments undertaken with isolated rat hepatocytes and with V79 cells transfected with human monoamine phenol sulfotransferase cDNA revealed that adduct formation required 1'-hydroxylation of estragole, followed by sulfation. The pattern of adducts expressed when the transfected V79 cells were incubated with 1'-hydroxyestragole was very similar to that expressed in livers of estragole-treated rats. These cells should constitute a valuable in vitro model system for investigation of toxicological consequences arising from estragole-induced protein adduct formation.

Public health implications of 1990 air toxics concentrations across the United States

Occupational and toxicological studies have demonstrated adverse health effects from exposure to toxic air contaminants. Data on outdoor levels of toxic air contaminants have not been available for most communities in the United States, making it difficult to assess the potential for adverse human health effects from general population exposures. Emissions data from stationary and mobile sources are used in an atmospheric dispersion model to estimate outdoor concentrations of 148 toxic air contaminants for each of the 60,803 census tracts in the contiguous United States for 1990. Outdoor concentrations of air toxics were compared to previously defined benchmark concentrations for cancer and noncancer health effects. Benchmark concentrations are based on standard toxicological references and represent air toxic levels above which health risks may occur. The number of benchmark concentrations exceeded by modeled concentrations ranged from 8 to 32 per census tract, with a mean of 14. Estimated concentrations of benzene, formaldehyde, and 1,3-butadiene were greater than cancer benchmark concentrations in over 90% of the census tracts. Approximately 10% of all census tracts had estimated concentrations of one or more carcinogenic HAPs greater than a 1-in-10,000 risk level. Twenty-two pollutants with chronic toxicity benchmark concentrations had modeled concentrations in excess of these benchmarks, and approximately 200 census tracts had a modeled concentration 100 times the benchmark for at least one of these pollutants. This comprehensive assessment of air toxics concentrations across the United States indicates hazardous air pollutants may pose a potential public health problem.

Neurotoxicity risk assessment of MPTP (N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) as a synthetic impurity of drugs

1-Methyl-4-phenyl-1,2,3,6 tetrahydropyridine (MPTP) induces symptoms indistinguishable from those of Parkinson's disease. It selectively destroys dopaminergic neurons in the substantia nigra and the globus pallidus. Death of these same neurons is apparently the cause of idiopathic Parkinson's disease. As phenyl-1,2,3,6 tetrahydropyridine is a commonly encountered subunit in heterocyclic drugs and because MPTP was found as a minor impurity in early batches of a candidate drug at Merck KGaA, it may be assumed that MPTP will also be present as an as yet undiscovered minor impurity in various existing drugs. A neurotoxicity risk assessment on MPTP has been conducted to define the risk of MPTP as an impurity in drugs that are used orally. This risk assessment has shown that compounds containing less than 5.0 p.p.m. MPTP administered orally will not cause a neurotoxicological health risk to patients treated with such a drug.

The disposition of allyl isothiocyanate in the rat and mouse

The urine was the major route of excretion of radioactivity (50-80% of dose) following the oral administration (2.5 and 25 mg/kg body weight) of allyl[14C]isothiocyanate (AITC) to male and female Fischer 344 rats and B6C3F1 mice. Smaller amounts were found in the faeces (6-12%) and expired air (3-7%). The major difference between the two species was the greater retention of radioactivity after 4 days within rats (18-24% of dose) when compared with mice (2-5% of dose). Three radioactive components were found in the urine of mice and two in rats. The three components were inorganic thiocyanate, allylthiocarbamoylmercapturic acid and allylthiocarbamoylcysteine in mice, but no cysteine conjugate was found in rat urine. In the mouse, approximately 80% of the 14C was present in the urine as the thiocyanate ion whereas in the rat some 75% was as the mercapturate. This indicates that in the mouse, hydrolysis of AITC was the major metabolic pathway whereas in the rat glutathione conjugation was the major route. A species difference was seen in the amount of [14C]AITC-derived radioactivity present in the whole blood of rats and mice; measurable levels of radioactivity remained within rat blood for a longer time period (up to 240 hr) when compared with mice (96 hr). Examination of the urinary bladders of male and female rats following oral dosing with [14C]AITC showed a sex difference with greater amounts of [14C]AITC and/or its metabolites within the bladder tissue of male rats. This data is discussed in terms of the known species- and sex-specificity of the urinary bladder tumours, which occurred after long-term administration to male rats, but not to female rats or mice of either sex, in a carcinogenicity study conducted by the National Toxicology Program in the USA.

Cytochrome P450 mediated bioactivation of methyleugenol to 1'-hydroxymethyleugenol in Fischer 344 rat and human liver microsomes

Cytochrome P450 mediated metabolism of methyleugenol to the proximate carcinogen 1'-hydroxymethyleugenol has been investigated in vitro. Kinetic studies undertaken in liver microsomes from control male Fischer 344 rats revealed that this reaction is catalyzed by high affinity (Km of 74.9 +/- 9.0 microM, Vmax of 1.42 +/- 0.17 nmol/min/nmol P450) and low affinity (apparent Km several mM) enzymic components. Studies undertaken at low substrate concentration (20 microM) with microsomes from livers of rats treated with the enzyme inducers phenobarbital, dexamethasone, isosafrole and isoniazid indicated that a number of cytochrome P450 isozymes can catalyze the high affinity component. In control rat liver microsomes, 1'-hydroxylation of methyleugenol (assayed at 20 microM substrate) was inhibited significantly (P < 0.05) by diallylsulfide (40%), p-nitrophenol (55%), tolbutamide (30%) and alpha-naphthoflavone (25%) but not by troleandomycin, furafylline, quinine or cimetidine. These results suggested that the reaction is catalyzed by CYP 2E1 and by another as yet unidentified isozyme(s) (most probably CYP 2C6), but not by CYP 3A, CYP 1A2, CYP 2D1 or CYP 2C11. Administration of methyleugenol (0-300 mg/kg/day for 5 days) to rats in vivo caused dose-dependent auto-induction of 1'-hydroxylation of methyleugenol in vitro which could be attributed to induction of various cytochrome P450 isozymes, including CYP 2B and CYP 1A2. Consequently, high dose rodent carcinogenicity studies are likely to over-estimate the risk to human health posed by methyleugenol. The rate of 1'-hydroxylation of methyleugenol in vitro in 13 human liver samples varied markedly (by 37-fold), with the highest activities being similar to the activity evident in control rat liver microsomes. This suggests that the risk posed by dietary ingestion of methyleugenol could vary markedly in the human population.

Effect of dexmedetomidine on lumbar cerebrospinal fluid pressure in humans

Dexmedetomidine's potential for analgesia without respiratory depression and its opioid- and anesthetic-sparing properties make it an attractive choice as an anesthetic adjunct for patients undergoing neurosurgery. However, the effects of dexmedetomidine on intracranial pressure are not known. We therefore studied the effect of dexmedetomidine on lumbar cerebrospinal fluid (CSF) pressure in patients after transphenoidal pituitary tumor surgery. Sixteen transphenoidal pituitary tumor surgery patients were randomized to receive placebo (n = 9) or dexmedetomidine (n = 7) for 60 min in the postanesthesia care unit. The study drug was administered by a continuous computer-controlled infusion to achieve an estimated plasma dexmedetomidine concentration of 600 pg/mL, the highest plasma concentration that has been used for clinical purposes. Patient-controlled analgesia was used to administer morphine for postoperative discomfort. Lumbar CSF pressure (via lumbar intrathecal catheter), intraarterial blood pressure, and heart rate were monitored continuously. There was no change in lumbar CSF pressure in either group. The highest values obtained were 19 mm Hg in the dexmedetomidine group and 20 mm Hg in the placebo group. During infusion, mean arterial pressure decreased from 103 +/- 10 mm Hg to 86 +/- 6 mm Hg (P < 0.05), heart rate decreased from 77 +/- 12 bpm to 64 +/- 7 bpm (P < 0.05), and cerebral perfusion pressure decreased from 95 +/- 8 mm Hg to 78 +/- 6 mm Hg (P < 0.05) in the dexmedetomidine group, but not in the placebo group. We conclude that dexmedetomidine does not have an effect on lumbar CSF pressure in patients with normal intracranial pressure who have undergone transphenoidal pituitary hypophysectomy.

IMPLICATIONS

The effects of dexmedetomidine (an alpha2-agonist) or placebo on lumbar cerebrospinal fluid pressure, measured via an intrathecal catheter, were studied postoperatively in 16 patients. Dexmedetomidine had no effect on lumbar cerebrospinal fluid pressure. We will continue to investigate the potential utility of dexmedetomidine for neurosurgical anesthesia.

Ethanol teratogenesis in the C57BL/6J, DBA/2J, and A/J inbred mouse strains

Research has shown variations in susceptibility to alcohol-related birth defects in humans. Genetic differences are one reason for this variability. This study compared three inbred mouse strains to determine whether they differ in their susceptibilities to ethanol teratogenesis because previous studies have generated conflicting data. Pregnant C57BL/6J (B6), DBA/2J (D2), and A/J (A) dams were intubated intragastrically with either an acute dose of ethanol (5.8 g/kg) or an isocaloric amount of maltose-dextrine on day 9 of pregnancy. Litters were removed on day 18 of pregnancy and examined for gross, soft-tissue, and skeletal malformations. Results showed that ethanol-exposed B6 litters had a higher percentage of digit (19%), kidney (24%), and skeletal (32%, mostly vertebral) malformations than their maltose-exposed controls (7% or below). Prenatal exposure to ethanol increased skeletal (68%, both rib and vertebral) malformations for A litters when compared to their maltose-exposed controls (4%), but did not increase digit or kidney malformations. Ethanol-exposed D2 litters did not differ from maltose-exposed controls. Maternal blood ethanol levels did not differ among the B6, D2, and A strains. These results provide additional evidence suggesting a genetic component to ethanol teratogenesis.

Personal names and the attentional blink: a visual "cocktail party" effect

Four experiments were carried out to investigate an early- versus late-selection explanation for the attentional blink (AB). In both Experiments 1 and 2, 3 groups of participants were required to identify a noun (Experiment 1) or a name (Experiment 2) target (experimental conditions) and then to identify the presence or absence of a 2nd target (probe), which was their own name, another name, or a specified noun from among a noun distractor stream (Experiment 1) or a name distractor stream (Experiment 2). The conclusions drawn are that individuals do not experience an AB for their own names but do for either other names or nouns. In Experiments 3 and 4, either the participant's own name or another name was presented, as the target and as the item that immediately followed the target, respectively. An AB effect was revealed in both experimental conditions. The results of these experiments are interpreted as support for a late-selection interference account of the AB.

Immunochemical identification of mouse hepatic protein adducts derived from the nonsteroidal anti-inflammatory drugs diclofenac, sulindac, and ibuprofen

Reactive metabolite-modified hepatic protein adducts have been proposed to play important roles in the mechanism(s) of hepatotoxicity of nonsteroidal anti-inflammatory drugs (NSAIDs). In the present study, immunochemical techniques have been used to compare the patterns of drug-protein adducts expressed in livers of mice given single doses of one or other of three different NSAIDs. These were diclofenac and sulindac, which are widely used but potentially hepatotoxic drugs, and ibuprofen, which is considered to be nonhepatotoxic. Specific polyclonal antisera were produced by immunization of rabbits with conjugates prepared by coupling each of the NSAIDs to the carrier protein keyhole limpet hemocyanin. Immunoblotting studies revealed dose-dependent formation of major 110 kDa polypeptide adducts in livers from mice sacrificed 6 h after administration of single doses of either diclofenac (0-300 mg/kg) or sulindac (0-100 mg/kg). Lower levels of several other adducts, of 140 and 200 kDa, were also expressed in livers from these animals. In contrast, livers from mice treated with ibuprofen (0-200 mg/kg) predominantly expressed a 60 kDa adduct and only relatively low levels of a 110 kDa adduct. The various adducts were shown by differential centrifugation to be concentrated in the nuclear fraction of liver homogenates. Those derived from diclofenac and sulindac were further localized, by Percoll density gradient centrifugation, to a subfraction which contained a high activity of the bile canalicular marker enzyme alkaline phosphatase. This suggests that they are concentrated in the bile canalicular domain of hepatocytes. The different patterns of adduct formation raise the possibility that formation of certain NSAID protein adducts, particularly 110 kDa adducts, has toxicological significance.