Objective. To compare the incidence and extent of coronary artery calcification (CAC) as measured by electron beam computed tomography (EBCT) in patients with systemic lupus erythematosus (SLE) and controls, and to identify variables associated with CAC in patients with SLE.Methods. Female patients with SLE and matched controls were recruited; EBCT of the coronary arteries was performed, and laboratory values (including the homocysteine concentration, the lipid level, the high- Results. The incidence of CAC was higher in patients with SLE than in controls (P ‫؍‬ 0.009), and patients had a higher mean raw CAC (rCAC) score (87.9 versus 9.6 in controls; P ‫؍‬ 0.02). In particular, more CAC-positive patients than CAC-positive controls had rCAC scores above the 75th percentile (P ‫؍‬ 0.003). Among both patients and controls, those with CAC were ϳ10 years older than those without CAC. In addition to age, a significant determinant of positive CAC status in both groups was the number of cardiovascular risk factors. In patients with SLE, CAC was associated with a higher homocysteine concentration, a lower GFR, and longer disease duration. In controls, the total cholesterol level correlated positively with CAC. When multivariate logistic regression methods were applied to candidate explanatory variables, homocysteine concentration, age, and disease duration (but not the levels of sCD154 or hsCRP) contributed significantly to CAC status. The methylenetetrahydrofolate reductase C677T genotype was not a predictor of hyperhomocysteinemia or CAC status.Conclusion. Among patients with SLE, the homocysteine concentration, the GFR, age, and disease duration were associated with CAC. CAC occurred more frequently and was more extensive in patients with SLE than in controls, suggesting that EBCT could be used to detect premature atherosclerosis in the former group. An elevated homocysteine concentration might identify patients with SLE who are likely to have premature atherosclerosis and who would benefit from evaluation of CAC by EBCT.

Excitatory amino acid (EAA) analogues activate receptors that are coupled to the increased hydrolysis of phosphoinositides (PIs). In these studies, hippocampal slices were prepared from neonatal rats (6-11 days old) to characterize the effects of EAA analogues on these receptors. The concentrations of ibotenate and trans-(+/-)-1-amino-1,3-cyclopentanedicarboxylate (trans-ACPD) required to evoke half-maximal stimulation (EC50 values) were 28 and 51 microM, respectively. Although the data for stimulation of PI hydrolysis by ibotenate and trans-ACPD were best fit to theoretical curves that had Hill slopes of 1, data for stimulation of PI hydrolysis by quisqualate were best fit to two sites. The EC50 values were 0.43 and 44 microM. The high-affinity sites were 70% of the total. A number of EAA analogues were tested for inhibition of PI metabolism. One of these, L-aspartate-beta-hydroxamate (L-A beta HA), was identified as a novel inhibitor of this response. L-A beta HA was equipotent as an inhibitor of PI metabolism stimulated by ibotenate, quisqualate, and trans-ACPD. The data for this inhibition were best fit to two sites. Between 32 and 48% of the total sites had high affinity with IC50 values in the range of 1.2-6.3 microM. The low-affinity sites had IC50 values between 610 and 2,700 microM. DL-2-Amino-3-phosphonopropionate (DL-AP3) was also equipotent as an inhibitor of PI hydrolysis stimulated by ibotenate, quisqualate, and trans-ACPD (IC50 values were 480-850 microM). In contrast to the data for L-A beta HA, the data for DL-AP3 were best fit to a single site. Both of these inhibitors reduced the maximal response caused by the agonists, consistent with noncompetitive mechanisms of action. Several experiments were designed to examine potential mechanisms for these noncompetitive effects. These studies suggest that either L-A beta HA and DL-AP3 bind to a site on the receptor and irreversibly block activation of the receptor, or that these inhibitors act via a distinct site that specifically regulates EAA receptors coupled to PI hydrolysis.

Objective. Elevated levels of tumor necrosis factor ␣ (TNF␣) have been identified in the synovium of patients with reactive and undifferentiated arthritis, implicating TNF␣ in the pathogenesis of these disorders. This finding has provided a rationale for the use of TNF␣ antagonists in the treatment of reactive arthritis; however, the possibility that the triggering microorganism might persist in affected joints and become activated with use of these agents has been of concern. Methods. The efficacy and safety of etanercept (25 mg subcutaneous twice weekly) in 16 patients with undifferentiated or reactive arthritis was assessed in a 6-month open-label trial. Synovial biopsies were performed before and after treatment with etanercept. Polymerase chain reaction (PCR) analysis was performed on the synovial biopsy samples to evaluate for the presence of nucleic acid material of bacterial organisms. Outcome measures including tender and swollen joint counts, pain assessment on a 10-point visual analog scale, and functional ability as measured by the Health Assessment Questionnaire were determined before and after etanercept therapy. Results. Ten of 16 patients completed the trial. Six patients withdrew, but none had a worsening of arthritis or infection.Of the 10 completers, 9 could be classified as treatment responders, despite the evidence of bacterial organisms on PCR analysis prior to initiating etanercept in 3 patients; 2 patients became PCR negative on etanercept. Five of 6 patients with adequate synovial biopsy specimens showed improvement, but not normalization of histology. Conclusion. Etanercept was well-tolerated without clinical exacerbation of any suspected underlying infections and appeared to provide therapeutic benefit in our cohort of patients with reactive and undifferentiated arthritis.