Renal biopsy findings and followup of renal function in rheumatoid arthritis patients treated with cyclosporin A. An update from the International Kidney Biopsy Registry.

OBJECTIVE: To review data from the International Kidney Biopsy Registry, which describes the occurrence of cyclosporin A (CSA)-induced nephropathy, and to discuss the potential risk factors for its development. METHODS: The report examines data on a total of 60 first and 14 second renal biopsies performed in rheumatoid arthritis (RA) patients treated with CSA for up to 87 months. RESULTS: Five of the 60 patients with RA included in the Biopsy Registry had findings consistent with CSA-induced nephropathy at first biopsy. One further patient had such findings at second biopsy. Of the 22 patients who started CSA at dosages < 4 mg/kg/day and subsequently received dosages no higher than 5 mg/kg/ day, none developed CSA-induced nephropathy. Continuous assessment of renal function did not show any evidence of deterioration over time in patients maintained on low-dose CSA. CONCLUSION: The data indicate that in RA patients being treated according to current dosing recommendations, the risk of developing CSA-induced nephropathy is low.

Neuroleptic malignant syndrome complicating levodopa withdrawal.

OBJECTIVE: To describe a case of neuroleptic malignant syndrome (NMS) resulting from withdrawal of low-dose levodopa therapy for mild Parkinson's disease. CLINICAL FEATURES: Treatment with levodopa, 50 mg, and benserazide, 12.5 mg, three times a day was withdrawn from a 76-year-old woman with mild Parkinson's disease because she was experiencing intermittent confusion. Fever (38.5 degrees C), tachycardia, increased confusion, severe rigidity and generalised stimulus-sensitive myoclonus developed after 12 hours. The creatine kinase level rose to 2058 U/L. INTERVENTION AND OUTCOME: The fever abated with reintroduction of levodopa. Rigidity was slow to resolve and required additional treatment with dantrolene sodium. CONCLUSION: NMS may be precipitated by withdrawal of relatively low doses of levodopa, even in patients with mild Parkinson's disease. Hyperthermia and rigidity in NMS may result from involvement of separate central dopaminergic pathways.

An experimental study of acoustoelectric transducers with nonuniform distribution of the piezoelectric coefficient.

In this paper, an experimental test of a theoretical model published previously is presented that describes the behavior of an acoustoelectric transducer with a nonuniform distribution of the piezoelectric coefficient within its bulk. Results of this theoretical model are first reviewed. Uniform and nonuniform piezoelectric transducers were fabricated, following a procedure described herein. The receive transfer functions of the transducers were recorded experimentally, and a comparison is made with the theoretical transfer functions predicted by the model, which shows good agreement. The transmit transfer functions of the uniform and nonuniform transducers were also measured and are reported. Numerical calculations of the different transfer functions given by the theoretical model for a uniform transducer associated with different backing materials are also presented, and the results are shown to be equivalent to the results following from the Mason equivalent circuit. Comparisons with experimental results and with Mason's equivalent circuit verified the new theoretical model.