[A giant cell arteritis revealing a Goodpasture's syndrome]. / Une artérite à cellules géantes révélatrice d'un syndrome de Goodpasture.

Goodpasture's syndrome is a triad of anti-glomerular basement membrane (anti-GBM) circulating antibodies, glomerulonephritis and pulmonary hemorrhage. We reported a 65-year-old woman with headaches, asthenia and weight loss. Giant cell arteritis was confirmed by temporal artery biopsy. The patient had associated renal condition with moderate acute renal failure, proteinuria and haematuria. Renal biopsy showed extracapillary glomerulonephritis and linear staining of immunoglobulins G along glomerular basement membrane. There was no clinical pulmonary involvement. Anti-MBG antibody was positive and allowed Goodpasture's syndrome diagnosis. The patient was treated with corticoids and cyclophosphamide. Patient's condition and renal function improved quickly and anti-MBG antibodies became negative. Goodpasture's syndrome may be characterized by isolated renal expression without pulmonary involvement. We described for the first time association of Goodpasture's syndrome with giant cell arteritis.

Intracellular Phosphate Dynamics in Muscle Measured by Magnetic Resonance Spectroscopy during Hemodialysis.

Of the 600-700 mg inorganic phosphate (Pi) removed during a 4-hour hemodialysis session, a maximum of 10% may be extracted from the extracellular space. The origin of the other 90% of removed phosphate is unknown. This study tested the hypothesis that the main source of phosphate removed during hemodialysis is the intracellular compartment. Six binephrectomized pigs each underwent one 3-hour hemodialysis session, during which the extracorporeal circulation blood flow was maintained between 100 and 150 ml/min. To determine in vivo phosphate metabolism, we performed phosphorous ((31)P) magnetic resonance spectroscopy using a 1.5-Tesla system and a surface coil placed over the gluteal muscle region. (31)P magnetic resonance spectra (repetition time =10 s; echo time =0.35 ms) were acquired every 160 seconds before, during, and after dialysis. During the dialysis sessions, plasma phosphate concentrations decreased rapidly (-30.4 %; P=0.003) and then, plateaued before increasing approximately 30 minutes before the end of the sessions; 16 mmol phosphate was removed in each session. When extracellular phosphate levels plateaued, intracellular Pi content increased significantly (11%; P<0.001). Moreover, ßATP decreased significantly (P<0.001); however, calcium levels remained balanced. Results of this study show that intracellular Pi is the source of Pi removed during dialysis. The intracellular Pi increase may reflect cellular stress induced by hemodialysis and/or strong intracellular phosphate regulation.

Renal perfusion: noninvasive measurement with multidetector CT versus fluorescent microspheres in a pig model.

PURPOSE: To validate the measurement of renal perfusion with multidetector computed tomography (CT) with a low-rate injection of contrast medium (ie, 3 mL/sec) through a catheter placed peripherally with gamma variate extended modeling in a pig model, compared with a reference method of fluorescent microspheres. MATERIALS AND METHODS: This study was approved by the Institutional Animal Care and Use Committee. Renal perfusion was measured in 10 anesthetized pigs simultaneously with multidetector CT and with fluorescent microspheres, which are the reference standard for measuring regional renal perfusion. In each pig, measurements were obtained under three conditions. These were dopamine infusion, dopamine infusion with vascular expansion, and angiotensin II infusion. Aortic and cortical time-attenuation curves were modeled to measure renal perfusion with the gamma variate model. The renal perfusion measurements with the multidetector CT and that with microspheres were compared with least squares regression analysis and Bland-Altman plots. RESULTS: Perfusion as measured with multidetector CT and that as measured with microspheres were strongly correlated (ρ = 0.93, P < .0001). Multidetector CT renal perfusion with dopamine infusion (3.13 mL/min/g ± 0.53) was not changed after volume expansion (3.37 mL/min/g ± 0.75, P = .35) but was significantly decreased after angiotensin II injection (2.01 mL/min/g ± 0.57, P = .0001). CONCLUSION: Multidetector CT provides reliable measurements of single-kidney perfusion with peripheral low-rate contrast medium injection.