The neuropsychology of de novo patients with idiopathic Parkinson's disease: the effects of age of onset.

One hundred de novo patients with Parkinson's disease (PD) were classified into two groups according to age of onset of symptoms. Seventy two patients were under 70 years and 28 were 70 years and over. All patients were given neurological and neuropsychological assessments, and the severity of the signs was rated on a modified Columbia scale. The neuropsychological assessment was also administered to 50 age-and-education-matched controls. The neuropsychological test battery included tests of verbal learning, visual memory, verbal fluency, visuospatial skill, simple and choice reaction time, language and maze learning. The late-onset patients had significant impairment in nonverbal reasoning, auditory verbal learning, visual memory and choice reaction time in contrast to early-onset patients and controls. A relationship was found between bradykinesia and widespread cognitive impairment. Severity of tremor was found to be significantly correlated with impairment in auditory verbal learning, visual memory and increased choice reaction time, while rigidity was found to be associated with cognitive impairment in verbal fluency and visuospatial skill. Using DSM II criteria, 39% of the late-onset and 8% of the early-onset group were classified as demented. Dementia was more common in patients with bilateral symmetrical disease and in those patients with marked tremor and bradykinesia. The pattern of cognitive impairment in PD was consistent with that associated with a subcortical dementia. This study confirms that the expression of PD is markedly influenced by the age of onset.

The Sydney Multicentre Study of Parkinson's disease: a report on the first 3 years.

One hundred and twenty nine de novo patients with idiopathic Parkinson's disease are being followed over a 5 year period in a double-blind multicentre study comparing low-dose bromocriptine (less than 30 mg/day) with low-dose levodopa-carbidopa (less than 600/150 mg/day). Sixty six patients have been randomised to bromocriptine and 63 patients to levodopa-carbidopa. Improvement has been greater in the levodopa-carbidopa group than in the bromocriptine group. Involuntary movements have so far only occurred in patients on levodopa-carbidopa, the incidence being much lower than is usually described with conventional doses. Mild, end-of-dose failure has occurred in both treatment groups; however, no patient has developed the "on-off" phenomenon. Low-dose levodopa-carbidopa appears to be a more effective anti-Parkinsonian treatment than low-dose bromocriptine but more prone to cause dyskinesia.

The Sydney multicentre study of Parkinson's disease. The first 18 months.

Low-dose bromocriptine therapy and low-dose levodopa-carbidopa therapy are being compared in a double-blind study over a five-year period as treatment for newly-diagnosed patients with Parkinson's disease. Ninety-four patients had entered the study by January 1986 and of these, 50 had been followed for six months or more. Preliminary results confirm that many patients with Parkinson's disease can be managed satisfactorily in the early stages of the disease with low-dose therapy. Three patients, all of whom were receiving levodopa-carbidopa therapy, developed dyskinesia. Twelve patients who had received bromocriptine had an inadequate response or developed confusion or postural hypotension. Of these patients, six had a poor response to subsequent levodopa-carbidopa therapy. While the initial improvement that results from low-dose bromocriptine therapy and low-dose levodopa-carbidopa therapy is less than one would expect with conventional doses of these agents, it is hoped that this approach will reduce the incidence of long-term side-effects such as dyskinesia and fluctuations.

Effect of linocmycin on the chlorophyll protein complex I content and photosystem I activity of greening leaves.

1. Greening barley and pea leaves treated with lincomycin have a reduced chlorophyll content. Lincomycin dose not alter the proportion of chlorophyll in chlorophyll-protein complex II (CPII) but greatly reduces that in chlorophyll-protein complex I (CPI). 2. Difference spectra show that chloroplasts from lincomycin-treated leaves are deficient in at least two long wavelength forms of chlorophyll ratio of chloroplasts is unaffected by lincomycin but the photochemical P-700/chlorophyll ratio is less than half of that of the control. It is less affected than the chlorophyll-protein complex I content. 4. Photosystem I activity expressed on a chlorophyll basis is unaffected by linocomycin but the light intensity for half saturation is increased 8-fold. 5. Chlorophyll-protein complex I apoprotein content is reduced by lincomycin. No evidence was found for an accumulation of its precursor(s). The relative abundance of major peptides of 18 000, 15 000 and 12 000 daltons in lincomycin-treated chloroplasts is attributed to a general inhibition of greening and associated membrane of formation.