Alison Cooper

Glutathione is a storage form of cysteine and protects against reactive oxygen species and potentially toxic xenobiotics in the central nervous system. Marked reductions in intracellular or intramitochondrial glutathione are associated with cell death. Enzymes involved in glutathione metabolism are very active in the choroid plexus, and astrocytes maintain a high concentration of glutathione. Astrocytes probably play an important role in regulating cerebral sulfur/glutathione metabolism and in protecting the brain against noxious chemicals. Oxidative stress contributes to age-related neurodegenerative diseases. Patients with inborn errors of glutathione metabolism often exhibit progressive neurological problems. Therefore, increasing brain glutathione levels may have therapeutic benefits.

OBJECTIVE: Many patients fail to attend cardiac rehabilitation. Attempts to identify sociodemographic or clinical predictors of non-attendance have not been very successful; therfore, this study aimed to determine whether the illness beliefs held during hospitalisation by patients who had suffered acute myocardial infarction or who had undergone coronary artery bypass graft surgery could predict cardiac rehabilitation attendance. SUBJECTS AND METHODS: 152 patients were prospectively studied of whom 41% had attended cardiac rehabilitation at six months. RESULTS: In addition to being older, less aware of their cholesterol values, and less likely to be employed, non-attenders were less likely to believe their condition was controllable and that their lifestyle may have contributed to their illness. CONCLUSION: It should now be determined whether interventions aimed at optimising certain perceptions could promote cardiac rehabilitation uptake among those patients who could benefit the most.

Neurones of the globus pallidus (GP) have been classified into three subgroups based on the visual inspection of current clamp electrophysiological properties and morphology of biocytin-filled neurones. Type A neurones (132/208; 63 %) were identified by the presence of the time- and voltage-dependent inward rectifier (Ih) and the low-threshold calcium current (It) giving rise to anodal break depolarisations. These cells were quiescent or fired regular spontaneous action potentials followed by biphasic AHPs. Current injection evoked regular activity up to maximum firing frequency of 350 Hz followed by moderate spike frequency adaptation. The somata of type A cells were variable in shape (20 x 12 micrometer) while their dendrites were highly varicose. Type B neurones (66/208; 32 %) exhibited neither Ih nor rebound depolarisations and only a fast monophasic AHP. These cells were spontaneously active while current injection induced irregular patterns of action potential firing up to a frequency of 440 Hz with weak spike frequency adaptation. Morphologically, these cells were the smallest encountered (15 x 10 micrometer), oval in shape with restricted varicose dendritic arborisations. Type C neurones were much rarer (10/208; 5 %). They were identified by the absence of Ih and rebound depolarisations, but did possess a prolonged biphasic AHP. They displayed large A-like potassium currents and ramp-like depolarisations in response to step current injections, which induced firing up to a maximum firing frequency of 310 Hz. These cells were the largest observed (27 x 15 micrometer) with extensive dendritic branching. These results confirm neuronal heterogeneity in the adult rodent GP. The driven activity and population percentage of the three subtypes correlates well with the in vivo studies (Kita & Kitai, 1991). Type A cells appear to correspond to type II neurones of Nambu & Llinas (1994, 1997) while the small diameter type B cells display morphological similarities with those described by Millhouse (1986). The rarely encountered type C cells may well be large cholinergic neurones. These findings provide a cellular basis for the study of intercellular communication and network interactions in the adult rat in vitro.