title: An analysis of six patients with Parkinson's disease who have been unresponsive to L-dopa therapy.
abstract: Six patients diagnosed as Parkinson's disease on a clinical basis alone are described, and their response to L-dopa and to alpha methyl dopa hydrazine (MK 486) and L-dopa. They are compared with 239 other patients with Parkinson's disease treated in the same time period. These six patients were unusual in that they did not have a clinical response to L-dopa, nor did they develop dyskinesias on L-dopa or on L-dopa with MK 486, although they showed high blood levels of L-dopa and high homovanillic acid levels in the spinal fluid. Unresponsiveness to L-dopa is attributed to a specific brain mechanism and not to problems of transport of L-dopa to the brain or to abnormal peripheral metabolism of L-dopa. The term `motor unresponsiveness to L-dopa' may be useful to describe such patients who may eventually be shown to be suffering from diseases other than Parkinsonism.
mesh_terms: D000368:Aged; D002230:Carbidopa / Q000008:administration & dosage / Q000627:therapeutic use; D003937:Diagnosis, Differential; D004295:Dihydroxyphenylalanine / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D005069:Evaluation Studies as Topic; D005260:Female; D006719:Homovanillic Acid / Q000134:cerebrospinal fluid; D006801:Humans; D006834:Hydrazines / Q000627:therapeutic use*; D008297:Male; D009127:Muscle Rigidity / Q000188:drug therapy; D009132:Muscles / Q000187:drug effects; D009460:Neurologic Examination; D010300:Parkinson Disease / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000188:drug therapy*; D014202:Tremor / Q000188:drug therapy
chemical_list: D006834:Hydrazines; D004295:Dihydroxyphenylalanine; D002230:Carbidopa; D006719:Homovanillic Acid