The significance of perivascular inflammation in the absence of arteritis in temporal artery biopsy specimens.

We retrospectively compared 81 temporal artery biopsy specimens demonstrating perivascular inflammation without evidence of temporal arteritis and 76 specimens demonstrating no inflammation. Patients with perivascular inflammation included 43 women (mean age, 71.2 years). Nineteen patients met the 1990 American College of Rheumatology (ACR) criteria for the diagnosis of temporal arteritis. All patients demonstrated chronic perivascular inflammation consisting primarily of lymphocytes. Granulomas were noted in 4 specimens. Internal elastic lamina disruption, intimal fibroplasia, and dystrophic calcification were noted in 86 arteries examined. Fibrosis or scarring of the vessel walls was observed in 10 specimens. Corticosteroid therapy was beneficial to 33 of 56 patients. In patients with no evidence of inflammation (50 women; mean age, 66.6 years), 21 met ACR criteria for temporal arteritis. Histologically, disruption of the elastic lamina was noted in 75 of 81 arteries biopsied, intimal fibroplasia in 66, microcalcifications in 5, and fibrosis or scarring in 5. In this group, 47 patients received corticosteroid therapy; clinical improvement was noted in 28. Patients with chronic perivascular inflammation but no arteritis seem no more likely to have temporal arteritis on clinical grounds than similar patients without inflammation on biopsy.

Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is a rare clonal disorder that consists of single or multiple mass lesions composed of cells with an abnormal Langerhans cell phenotype. Its etiology remains unknown, despite extensive searches for evidence of consistent cytogenetic abnormalities, gene rearrangements, or viral genomes. Similarly, the pathogenesis of the disease is enigmatic, although the altered expression of cytokines and cellular adhesion molecules, important for migration and homing of the activated normal Langerhans cell, may play an important role. The biologic behavior of LCH ranges from spontaneous remission to lethal dissemination, and such behavior cannot be predicted on the basis of histologic features. The presence and degree of organ dysfunction, together with the patient's age at diagnosis, remain the most reliable indicators of prognosis. Treatment of severe, refractory disease continues to be controversial and, in many cases, ineffectual. The revised classification scheme for LCH and related disorders recognizes the uncertain biological potential of LCH and its relation to other processes of dendritic and macrophage origin.

Synthesis and renal excretion of technetium-99m-labeled organic cations.

Organic cations are excreted more efficiently than organic anions in uremia suggesting superiority as renal imaging agents. In this study, three 99mTc-labeled cationic cyclam complexes were synthesized and their renal clearance quantified in rats. The complexes are cleared at a rate of about 2.5-3 times that of inulin and about 60% that of p-amino-hipurate. Inhibition of 99Tc-cyclam excretion by quinine indicates transport by the organic cation process. Comparative in vivo imaging experiments demonstrated that in normal rats 99mTc-cyclam reached peak renal activity 1.8 +/- 0.6 min after injection, a value intermediate between that for [131I]OIH (1.0 +/- 0) and 99mTc-MAG3 (2.8 +/- 0.6). In rats injected with the acute nephrotoxin cisplatin, the times to peak were lengthened with the relative order being 99mTc-cyclam > 99mTc-MAG3 > [131I]OIH. The results demonstrate that cationic complexes may be useful for renal imaging diagnostic applications.