Janice E. Christie

Magnetic resonance imaging in pre-senile dementia of the Alzheimer-type, multi-infarct dementia and Korsakoff's syndrome

Magnetic resonance imaging T1 values in Alzheimers disease (ATD) were similar to age-matched controls although frontal T1 values tended to increase intraindividually with progression of the dementia. T1 values were raised, in both cortical grey and white matter, in Korsakoffs syndrome and multi-infarct dementia. T1 values appear of little value in studying the neuropathological changes in ATD in relationship to the neuropsychological deficits, but can assist in the differential diagnosis of pre-senile dementia.

DIURNAL-VARIATION OF PLASMA-CORTICOSTERONE IN DEPRESSION

Hypersecretion of cortisol is associated with depression. Because corticosterone may show greater responsiveness than cortisol to exogenous ACTH in depression and it has behavioural effects in rodents, we determined whether depression is also associated with hypersecretion of corticosterone. Both cortisol and corticosterone were significantly elevated in depression, with greatest differences from control subjects during the afternoon and evening. The ratio of corticosterone/cortisol was constant and similar throughout the day in both depressed patients and controls. We conclude that there is no disproportionate endogenous hypersecretion of corticosterone in depression.

Autoantibodies to Alzheimer and normal brain structures from virus-transformed lymphocytes

B-Lymphocytes from two patients with Alzheimers disease and one healthy subject were transformed into lymphoblastoid cells by exposure to Epstein-Barr virus. In culture, more than 50% of these cells secreted sufficient IgM or IgG antibody (mainly IgM) to allow immunohistochemical screening against cryostat sections of normal and Alzheimer temporal cortex. More than 30% of the IgM antibodies from each subject recognised brain components, namely: neurons, astrocytes, nuclei, nucleoli, and Alzheimer plaques and neurofibrillary tangles. This methodology represents a major addition to the procedures currently available for the generation of antibodies towards normal and pathological structures in human brain.

Cholinergic enzymes in the spinal cord in Alzheimer-type dementia

SummaryCholine acetyltransferase (ChAT) and acetylcholinesterase (AChE) were measured in anterior and posterior grey matter of the lumbar spinal cord and in temporal and frontal cortex from six cases of Alzheimer-type dementia (ATD), one case of Downs syndrome, three cases of schizophrenia (SZ) and six controls. Compared with control and SZ values, ChAT and AChE were reduced in ATD cerebral cortex. ChAT was reduced, and AChE unaltered, in ATD spinal cord. Decreased cord ChAT may be related to electrophysiological abnormalities which have been reported in motor nerves of patients with Alzheimers disease.

REDUCED PLASMA OESTROGEN STIMULATED NEUROPHYSIN AND DELAYED RESPONSE TO OESTROGEN CHALLENGE IN ALZHEIMER'S DISEASE

Plasma concentrations of oestrogen stimulated neurophysin (ESN) were reduced in 28 patients with Alzheimers disease (AD) compared with 14 age-matched controls, 16 patients with other presenile dementias and 12 patients with major depressive disorder. The ESN response to oestrogen challenge was delayed in 10 AD patients compared with 7 age-matched controls. Reduced basal and oestrogen stimulated plasma ESN may be related to impaired responsiveness of the hypothalamo-neurohypophysial neurons and/or a reduction in the amount of pituitary ESN available for release. Plasma ESN measurements may be of value for excluding the diagnosis of AD in patients with dementia who present before the age of 65.

Effect of electroconvulsive therapy (ECT) on plasma tryptophan

The concentrations of total and free plasma tryptophan were measured in 12 unipolar depressed patients before and after a course of electroconvulsive therapy (ECT) and before and after single ECTs during the course of treatment. Eleven patients undergoing diagnostic cystoscopy served and controls to examine the acute effect of anaesthesia. Total and free plasma tryptophan concentrations in the depressed patients were not significantly different from control values and were not changed by course of ECT. Free plasma tryptophan varied considerably within individual patients. Total plasma tryptophan was reduced acutely by ECT/anaesthesia in the depressed patients (P less than 0.05) and by anaesthesia in the cystoscopy controls (P less than 0.01). Free plasma tryptophan was not significantly altered. This reduction in total plasma tryptophan could be secondary to an effect of thiopentone on albumin binding of tryptophan.