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Current Science Reviews by Joe Bruman April 1996 Time: 11 Mar 1996:60 (news item): Dopamine in the brain produces intense pleasure, and every addictive substance does so by increasing dopamine. Researchers found that smokers averaged 40% less MAO-B, an enzyme in the brain that breaks down dopamine. They theorize that some unknown component of tobacco is a MAO-B inhibitor. Nicotine also increases dopamine level, but in a different way, by blocking dopamine receptors in the forebrain. Lancet; 24 Feb 1996:527 (news item): Reduced MAO-B in smokers may lessen the risk of PD, explain addictive properties of cigarettes, and enhance cognitive performance. The component of tobacco that inhibits MAO-B is unknown. Olanow C; JAMA: 6 Mar 1996:716: Very detailed discussion of onset, diagnosis, treatment, and progression of PD in a fairly "typical" patient with a professional background. Anon; Neur 1996;46:278-285: Tutorial review by 13 experts on Single-Photon Emission Computed Tomography (SPECT). Unlike PET, which maps specific neural activity by means of a radioactive analog of dopamine, SPECT usually depicts only the general distribution of its tracer, supposedly indicating the delivery of nutrients to various brain areas. Receptor-binding tracers are being developed, but none is yet approved for clinical use. While less effective than PET, SPECT as also much cheaper. Marek K et al; Neur 1996;46:231-237: SPECT using a dopamine transporter with radioactive iodine (see above) detected reduction of striatal uptake in 8 early-stage PD patients, compared with 8 healthy controls. Reduction was greater in the putamen than in the caudate. The experiment demonstrates possibility of using SPECT to detect latent PD before onset of motor symptoms. Lancet; 16 Mar 1996:751: (news item): Contrary to former belief, several research groups found the brain has regenerative power. It contains "stem" cells that, with various nerve growth factors, can reproduce and differentiate to any functional type. Defer G-L et al; Brain 1996;119:41-50: Five fetal transplant patients followed for 15 to 36 months showed gain in fluorodopa uptake, improvement in skilled hand movements, moderate improvement in on-off fluctuation, and greatly reduced dyskinesia, but no clear effect on walking, gait, or speech. All needed continued L-dopa but could reduce or stop other dopaminergic drugs. Three of the five developed new dyskinesia later in the followup period. J. R. Bruman (818) 789-3694 3527 Cody Road Sherman Oaks CA 91403