Successful use of rituximab in granulomatosis with polyangiitis with aortic inflammation

Large-vessel inflammation, although rare, has been increasingly recognised as a complication of granulomatosis with polyangiitis (GPA) in recent years. The presentation is highly variable, ranging from an incidental finding to aortic dissection and rupture. Treatment has predominately consisted of a combination of cyclophosphamide and high dose corticosteroids with surgical intervention when indicated. We present the case of a 34-year-old male diagnosed with GPA after presenting with sinus and eye inflammation and the ensuing investigation revealed large vessel involvement that remarkably improved after 6 months of treatment with the combination of rituximab infusions, methotrexate and corticosteroids.

Antinuclear antibodies in the general population: positive association with inflammatory and vascular biomarkers but not traditional cardiovascular risk factors

OBJECTIVES

Patients with clinically evident autoimmune disease are at increased risk for premature cardiovascular disease (CVD). Markers of serological autoimmunity such as anti-nuclear antibodies (ANA) are found in approximately 25% of the general population. Yet, the vast majority will not develop clinical autoimmune disease. Serological autoimmunity is a risk factor for CVD death in individuals without autoimmune disease; however, the mechanisms mediating this excess CVD risk have not been elucidated.

METHODS

We examined associations of ANA with traditional cardiovascular risk factors, inflammatory mediators, and vascular biomarkers in the Dallas Heart Study - a large, representative multiethnic population-based cohort. Plasma ANA were measured by enzyme linked immunosorbent assay in 3,488 Dallas Heart Study participants aged 30 to 65 years who do not have known rheumatologic disease. Associations of ANA with demographic characteristics, cardiovascular risk factors, and biomarkers were assessed using univariable and multivariable linear regression.

RESULTS

Factors independently associated with higher ANA include female sex, African-American race/ethnicity, soluble intracellular adhesion molecule-1, soluble CD40 ligand, chemokine CXCL-2, and Cystatin C (p<0.05 for each). ANA was not associated with traditional cardiovascular risk factors, high sensitivity C-reactive protein, coronary artery calcium scores, or aortic wall thickness.

CONCLUSION

ANA are associated with inflammatory mediators and biomarkers of vascular activation, but not with traditional cardiovascular risk factors in a multiethnic population-based cohort. These findings suggest that the cardiovascular risk associated with ANA may involve pathways distinct from traditional risk factors and include dysregulation of endothelial cells and the immune system.

Laboratory evaluation of skin refrigerants used in dermabrasion

Six skin refrigerants were evaluated for maximum cooling temperature. The temperatures produced correlated well with the chemical components and also the gelatin freeze-thaw times. Freon 114 and Freon 114-ethyl chloride mixtures are time-tested, safe skin refrigerants. Some of the newer skin refrigerants are pure sources of Freon 12 or mixtures of Freon 12 and Freon 11. These newer, colder products have the potential to damage the skin and represent a hazard to successful dermabrasion.

Plasma and red blood cell concentrations of amiodarone during chronic therapy

Amiodarone and a metabolite, desethylamiodarone, were measured in plasma of 55 patients and in both plasma and red blood cell (RBC) in 28 patients who received chronic amiodarone treatment. The assay for amiodarone and desethylamiodarone was performed by high-pressure liquid chromatography. During chronic treatment, median plasma concentration of amiodarone was 2.80 micrograms/ml and desethylamiodarone was 2.20 micrograms/ml. In matched samples, plasma amiodarone concentration exceeded RBC amiodarone concentration (p less than 0.001) and the RBC-to-plasma concentration ratio averaged 0.31. The plasma desethylamiodarone concentration was not significantly different from its RBC concentration, and the RBC-to-plasma concentration ratio averaged 1.29. There was a linear correlation between plasma concentrations of amiodarone and desethylamiodarone (r = 0.82) and between RBC concentrations of drug and metabolite (r = 0.71). Drug or metabolite concentrations in plasma and RBCs correlated directly with daily dosage of amiodarone. Adverse side effects during chronic amiodarone therapy were related most strongly to RBC drug and metabolite concentrations. The group with adverse side effects had a significantly higher RBC concentration of amiodarone, 150 vs 0.75 micrograms/ml (p less than 0.001), than did patients free of adverse effects. After dosage reduction, side effects abated and plasma and RBC concentrations of drug and metabolite decreased. These data indicate that there is an expected range of amiodarone and desethylamiodarone concentrations during chronic treatment and that adverse side effects correlate best with RBC concentrations of drug and metabolite. Red cell concentrations may reflect the amount of unbound, free amiodarone and desethylamiodarone in plasma.

Monitoring drug concentrations in a case of combined overdosage with primidone and methsuximide

We describe a case of fatal overdosage with primidone and methsuximide. During the early phase of the patient's hospital course we found concentrations of methsuximide, N-desmethylmethsuximide, and primidone in serum that far exceeded the usual therapeutic concentrations, as determined by gas-liquid chromatography. Determination of N-desmethylmethsuximide in peritoneal fluid demonstrated concentrations comparable to those in serum. This led to the therapeutic decision to manage the patient by dialysis. Subsequently, serum samples collected during the course of hospitalization were analyzed quantitatively by gas-liquid chromatography for methsuximide, N-desmethylmethsuximide, primidone, phenobarbital, and diphenylhydantoin. Selected serum specimens were also analyzed by gas chromatography-mass spectrometry, and N-methyl-2-hydroxymethyl-2-phenylsuccinimide, a metabolite of methsuximide not previously described in human serum, was identified by analysis of its mass spectrum.

Monitoring drug concentrations in a case of combined overdosage with primidone and methsuximide

We describe a case of fatal overdosage with primidone and methsuximide. During the early phase of the patient's hospital course we found concentrations of methsuximide, N-desmethylmethsuximide, and primidone in serum that far exceeded the usual therapeutic concentrations, as determined by gas-liquid chromatography. Determination of N-desmethylmethsuximide in peritoneal fluid demonstrated concentrations comparable to those in serum. This led to the therapeutic decision to manage the patient by dialysis. Subsequently, serum samples collected during the course of hospitalization were analyzed quantitatively by gas-liquid chromatography for methsuximide, N-desmethylmethsuximide, primidone, phenobarbital, and diphenylhydantoin. Selected serum specimens were also analyzed by gas chromatography-mass spectrometry, and N-methyl-2-hydroxymethyl-2-phenylsuccinimide, a metabolite of methsuximide not previously described in human serum, was identified by analysis of its mass spectrum.

Gas-chromatographic determination of an antifibrinolytic drug, epsilon-aminocaproic acid

We describe a modified method for assay of epsilon-aminocaproic acid. Serum or cerebrospinal fluid is deproteinized, followed by cation-exchange column-chromatography, and N-trifluoroacetyl-n-butyl derivatives of amino acids are formed and separated by gas chromatography. Tranexamic acid, a nonprotein amino acid, was used as an internal standard. The assay is sensitive and precise, and results correlate adequately with those obtained with an automated amino acid analyzer (ion-exchange chromatography).

Gas-chromatographic determination of an antifibrinolytic drug, epsilon-aminocaproic acid

We describe a modified method for assay of epsilon-aminocaproic acid. Serum or cerebrospinal fluid is deproteinized, followed by cation-exchange column-chromatography, and N-trifluoroacetyl-n-butyl derivatives of amino acids are formed and separated by gas chromatography. Tranexamic acid, a nonprotein amino acid, was used as an internal standard. The assay is sensitive and precise, and results correlate adequately with those obtained with an automated amino acid analyzer (ion-exchange chromatography).