摘要:

The social and public health importance of dementia has been greatly increased by the unprecedented expansion in the world's elderly. By the year 2000, the number of persons in the world aged 65 and over is expected to be about 423 million, nearly 50% of whom will be in developing countries (W.H.O., (1)). Furthermore, it is among the very elderly that the greatest increase is taking place. There will therefore be a marked expansion in the number of persons afflicted by dementia. Because of the profound human and economic consequences of this, there has been a striking increase in research activity in four areas: neurobiological studies, including the molecular biology of Alzheimer's disease (AD); epidemiological research on the dementias and on risk factors for developing it; a search for pharmacological interventions; and research on services for dementia sufferers and their families.

ISSN:0001-6314    

DOI:10.1111/j.1600-0404.1993.tb04243.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The neurochemical pathology of Alzheimer's disease (AD) has been consistently shown to involve cholinergic degeneration in the cerebral cortex. This together with evidence from experimental animal studies showing that cholinergic neurones play a role in learning and memory processes has formed the basis of the cholinergic hypothesis of Alzheimer's dementia and the major rationale for neurotransmitter replacement therapy of the disorder.

ISSN:0001-6314    

DOI:10.1111/j.1600-0404.1993.tb04244.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Cholinesterase inhibitors, such as physostigmine and tacrine, have lately gained interest as potential drugs in the treatment of Alzheimer's disease. Already in the 1950ths, it was discovered that physostigmine and tacrine were potent inhibitors of acetylcholinesterase and butyrylcholinesterase. However, later studies have shown that cholinesterase inhibitors also interact with cholinergic receptors, with sodium and potassium ion channels and effect the uptake, synthesis and release of neurotransmitters. In summary, cholinesterase inhibitors are drugs with many modes of action, which may be of advantage in the treatment of a complex disorder such as Alzheimer's disease.

ISSN:0001-6314    

DOI:10.1111/j.1600-0404.1993.tb04245.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Clinical trials with tacrine (THA) have resulted in elevations of liver enzymes in Alzheimer patients that showed improvement. In an effort to minimize these side effects several THA analogues were synthesized. These analogues were compared to THA in biochemical as well as behavioural studies. The biochemical effects of these drugs on plasma cholinesterase activity and cholinergic receptors as well as the effect of these drugs on spatial learning in adult rats were examined. It is possible that some of these analogues with more potent cholinergic effect than THA might be the next generation of cholinesterase inhibitors which can be useful in the treatment of Alzheimer's disease.

ISSN:0001-6314    

DOI:10.1111/j.1600-0404.1993.tb04246.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Research on memory enhancing effects of acetylcholinesterase (AChE) inhibitors was stimulated by the finding of diminished cholinergic markers in patients with Alzheimer's disease, and the correlation of cognitive impairment to cholinergic deficits in these patients. The rationale for the use of AChE inhibitors is based on their abilities to prevent breakdown of acetylcholine released from surviving nerve terminals. In experimental animals the AChE inhibitor has been found by some investigators to be efficacious in improving cognitive function. Recent work has focused more on the performance and memory enhancing effects of tetrahydroaminoacridine (THA). THA has been found to improve performance in experimental animals with cognitive impairments induced by a variety of experimental manipulations such as by pharmacological blockade, cholinergic lesions, chronic alcohol or barbital treatment and ischemic lesion. These findings are compatible with the view that AChE inhibitors can be efficacious in “restoration” of some cholinergic functi

ISSN:0001-6314    

DOI:10.1111/j.1600-0404.1993.tb04247.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

We have studied whether it is possible to discriminate responders to tacrine treatment from patients nonresponsive to tacrine in Alzheimer's disease. The results indicate that mildly demented patients will most likely gain a benefit of tacrine treatment. Neuropsychological tests on attention and working memory after a single dose of tacrine might be useful as well as a single dose pharmaco‐EEG in discriminating responders to treatmen

ISSN:0001-6314    

DOI:10.1111/j.1600-0404.1993.tb04248.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The pharmacokinetic of some centrally acting cholinesterase inhibitors that have been used to improve memory in patients with dementia of Alzheimer's type, was compared. The original compound in this class, physostigmine has an elimination half‐life of 20–30 min. Galanthamine, tacrine and the metabolite 1‐hydroxytacrine (velnacrine) have longer elimination half‐lives of 1.6–6 hours mainly due to a larger volume of distribution. The concentration of tacrine in the cerebrospinal fluid (CSF) was less than the average plasma concentration in the dosing interval; a ratio of 0.74. The concentration of 1‐hydroxytacrine and other metabolites of tacrine in the CSF were higher than the average concentrations of the compound

ISSN:0001-6314    

DOI:10.1111/j.1600-0404.1993.tb04249.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The paper reviews the results obtained with velnacrine, a cholinesterase inhibitor and potential Alzheimer's disease agents, in early clinical studies in healthy volunteers and patients with probable Alzheimer's disease (AD). In healthy subjects, the compound was demonstrated to reverse cognitive impairment induced by scopolamine. Single doses of velnacrine improved performance of patients with AD in simple recognition tasks and enhanced regional cerebral blood flow in prefrontal‐parietal areas. In a short crossover‐study, velnacrine was demonstrated to be significantly (<0.05) superior to placebo in the cognitive behaviour subscale of the ADAS, a word recognition task and, in trend, also on the Clinical Global Impression of Improvem

ISSN:0001-6314    

DOI:10.1111/j.1600-0404.1993.tb04250.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

A placebo‐controlled cross‐over trial (n=89) investigated the use of a chronic dose of the cholinesterase inhibitor THA, as a treatment for dementia of the Alzheimer type (DAT). Effects on both subjective clinical rating scales and objective computerised tests were assessed. In regard to the former, analysis of the three main clinical outcome measures showed statistically significant effects of the drug on the Mini‐Mental State Examination (MMSE) and the Abbreviated Mental Test Score (AMTS), but not on the Activities of Daily Living scale (ADL). Using the objective computerised CANTAB tests, sensitive to specific aspects of memory and attention, evidence was found for improvements in attentional function rather than memory, in patients with mild to moderate DAT. Although these improvement: were significant, they were small and restricted to certain tests of attentional function. Nevertheless, they add to the growing body of evidence that the cholinergic system is involved in the control of attentional processes: and are substantiated by the findings of a second study examining the effects of an acute dose of nicotine on attentional and mnemonic performance in patients with DAT. This study found significant improvements in cognitive performance in patients receiving nicotine, in objective tests of attention but not of short‐term memory. These data will clearly provide important comparative data for future investigations of putative cognitive enhancing drugs in DAT su

ISSN:0001-6314    

DOI:10.1111/j.1600-0404.1993.tb04251.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

A clinical comparison of tacrine (THA) and placebo was performed in 15 Alzheimer patients using a double blind crossover technique over 4 plus 4 weeks with one drug‐free week in between. Treatment results, as evaluated by clinical rating scales and neuropsychological tests, were mostly negative. Side effects were few, except for elevation liver enzymes which occured in one third of the patients. CSF levels of the monoamine metabolites HVA and 5‐HIAA increased on tacrine as evidence for activation of dopamine and serotonin pathways through cholinergic receptors. Pharmacokinetic investigations showed that the oral bioavailability of tacrine was low and greatly varying between subjects. Patients with high bioavailability of the drug tended to improve more, and also to have more liver enzyme elevations, than those with low bioavailability. A gel preparation for rectal administration was manufactured for comparison of plasma levels attained during one week's treatment with levels attained with oral capsules. Preliminary results indicate that the dose of tacrine can be reduced to 50 per cent when administered rectally, probably as by this route the rapid first‐pass metabolism of the drug in the liver is diminished. A clinical trial of tacrine via the rectal route would be justified as this could decrease the number of patients with liver side effects and increase the number of patients improving on the trea

ISSN:0001-6314    

DOI:10.1111/j.1600-0404.1993.tb04252.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY