Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Methanesulfonyl fluoride (MSF), a highly selective CNS inhibitor of acetylcholinesterase, has been recently demonstrated to promote improvement in cognitive performance in patients with senile dementia of Alzheimer type. Because a similar cognitive impairment may accompany stroke, we investigated in the present study whether treatment with MSF could produce beneficial effects in adult rats subjected to an experimental stroke model. Sprague-Dawley rats received transient 60 min intraluminal occlusion of the right middle cerebral artery (MCAo) and were given i.p. injections of either MSF (1 mg/kg at 24 and 48 h post-MCAo and 0.3 mg/kg thereafter every other day) or the vehicle, peanut oil, for 4 weeks. Behavioral tests and biochemical assays were performed at 28 days post-surgery. MSF treatment produced about 90% inhibition of acetylcholinesterase in the brain. Ischemic animals that received the vehicle displayed significant elevated body swing biased activity (84.8 +/- 10%) and significantly prolonged acquisition (398 +/- 62 s) and shortened retention (79 +/- 26 s) of the passive avoidance task. Interestingly, while the ischemic animals that received the MSF exhibited elevated body swing biased activity (87.7 +/- 8%), they performed significantly better in the passive avoidance task (255 +/- 36 s and 145 +/- 18 s in acquisition and retention) than the vehicle-treated animals. Moreover, whereas brains from both groups of animals revealed similar extent and degree of cerebral infarction, the MSF-treated ischemic animals showed more intense immunoreactivity, as well as a significantly higher number (10-15% increase) of septal choline acetyltransferase-positive cells than the vehicle-treated ischemic animals. These results show that MSF, possibly by preserving a functional cholinergic system, attenuated stroke-induced deficits in a simple learning and memory task.
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PMID:Methanesulfonyl fluoride, an acetylcholinesterase inhibitor, attenuates simple learning and memory deficits in ischemic rats. 1574 72

As clinicians we talk about "the best interests of our patients". How can a treatment which doubles the rate of cognitive decline, triples the rate of stroke, doubles mortality, substantially increases falls and fractures and reduces quality of life be beneficial, especially, as in real life, once neuroleptics are started they are rarely discontinued with cumulative adverse effects? As there is clearly no rational reason for prescribing, we need to consider other explanations. We would suggest the following: Therapeutic impotence: Doctors, especially specialists feel they need to do something, and prescribing a familiar drug is the easiest option. Ignorance: Doctors are either unaware of the substantial evidence of harm with neuroleptics or are swayed by slick marketing information, portraying atypical neuroleptics in an "over-safe" light that does not reflect the actual data. Placebo effect: If neuroleptics are prescribed, the majority of patients experience an improvement in BPSD symptoms. This reinforces the apparent value of this practice, as we like to take the credit for any improvements that occur. The reality is that the majority of people would have experienced a comparable improvement with monitoring. Bowing to pressure: Sometimes the pressure to respond can be great, and a prescription is an easy way to relieve the pressure. This is understandable, and reflects a similar phenomenon to that of general practioners prescribing antibiotics for sore throats. In neither situation does it represent good practice. Lack of skills to implement non-pharmacological alternatives: The main evidence for alternative treatment options are for therapies that by and large are not a core part of the physician or psychiatrist's skill-base, such as psychological interventions. Doctors therefore feel uncomfortable pursuing these options. Why for example is so little time spent on the nonpharmacological interventions that everyone agrees should be the first line of treatment for BPSD in people with dementia? It is largely assumed that the "enlightened clinician has already appropriately assessed and diagnosed the patient and exhausted all the possible environmental and behavioral interventions before resorting to the prescription pad." Accumulating evidence clearly indicates that the need for psychotropic medication is substantially reduced by proactive services or interventions which can provide training and promote psychological, social and environmental and sensory interventions. The prescription but is an easy but not an acceptable alternative. Over-adherence to prescribing guidance: There are pharmacological alternatives to neuroleptics if a prescription is needed. Although the evidence for the more promising alternatives needs to be developed much further, drugs such as cholinesterase inhibitors may offer a much less harmful alternative. The reluctance of clinicians to use cholinesterase inhibitors in this way is puzzling, and presumably is because of the culture of "guidance-prescribing" that has evolved around these agents. If the treatment of BPSD is to move forward, we need to challenge the way we have always done things, examine the evidence and move forward with new and flexible multi-disciplinary approaches if we are truly to look after the "best interests of our patients".
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PMID:Drugs used to relieve behavioral symptoms in people with dementia or an unacceptable chemical cosh? Argument. 1594 89

Patients with vascular dementia (VaD) and Alzheimer's disease with cerebrovascular disease (AD + CVD) have dementia associated with underlying CVD. Although diagnosis of VaD is challenging, VaD is typically characterized by a stepwise progression of dementia that is closely associated with stroke and focal neurological findings, and a symptom profile that often includes executive dysfunction leading to decreased ability to perform instrumental activities of daily living (IADL). In contrast, AD + CVD patients typically present with progressive deterioration of cognition/memory that may also be influenced by concurrent cerebrovascular events. Early diagnosis and intervention are desirable to prevent further decline due to subsequent vascular events. Management of CVD can limit deterioration of cognitive symptoms in VaD patients, and treatment benefits with cholinesterase inhibitors may be realized as improvement above baseline levels in dementia symptoms. Results from a combined analysis of two 24-week, placebo-controlled clinical trials show that donepezil-treated VaD patients improve in cognition, global function, and performance of IADL. In contrast, AD + CVD patients may continue to decline despite management of CVD, and treatment benefits should be recognized as initial improvements followed by stabilization or slowed decline of dementia symptoms over time. In post-marketing studies, donepezil-treated AD and AD + CVD patients show similar benefits in cognition, global function, and quality of life. The results of these studies support the use of donepezil in treatment of patients with VaD or AD + CVD.
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PMID:Dementia with cerebrovascular disease: the benefits of early treatment. 1614 33

Accompanying the gradual rise in the average age of the population of most industrialized countries is a regrettable progressive rise in the number of individuals afflicted with age-related neurodegenerative disorders, epitomized by Alzheimer's disease (AD) but, additionally, including Parkinson's disease (PD) and stroke. The primary therapeutic strategy, to date, involves the use of cholinesterases inhibitors (ChEIs) to amplify residual cholinergic activity. The enzyme, acetylcholinesterase (AChE), along with other elements of the cholinergic system is depleted in the AD brain. In contrast, however, its sister enzyme, butyrylcholinesterase (BuChE), that likewise cleaves acetylcholine (ACh), is elevated and both AChE and BuChE co-localize in high amounts with the classical pathological hallmarks of AD. The mismatch between increased brain BuChE and depleted levels of both ACh and AChE, particularly late in the disease, has supported the design and development of new ChEIs with a preference for BuChE; exemplified by the novel agent, cymserine, whose binding kinetics are characterized for the first time. Specifically, as assessed by the Ellman method, cymserine demonstrated potent concentration-dependent binding with human BuChE. The IC50 was determined as 63 to 100 nM at the substrate concentration range of 25 to 800 microM BuSCh. In addition, the following new binding constants were investigated for human BuChE inhibition by cymserine: T(FPnubeta), K(nubeta), K(Bs), K(MIBA), M(IC50), D(Sc), R(f), (O)K(m), OIC100, K(sl), theta(max) and R(i). These new kinetic constants may open new avenues for the kinetic study of the inhibition of a broad array of other enzymes by a wide variety of inhibitors. In synopsis, cymserine proved to be a potent inhibitor of human BuChE in comparison to its structural analogue, phenserine.
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PMID:Kinetic analysis of the inhibition of human butyrylcholinesterase with cymserine. 1630 45

Receptors have a prominent role in brain function, as they are the effector sites of neurotransmission at the postsynaptic membrane, have a regulatory role on presynaptic sites for transmitter reuptake and feedback, and are modulating various functions on the cell membrane. Distribution, density, and activity of receptors in the brain can be visualized by radioligands labeled for SPECT and PET, and the receptor binding can be quantified by appropriate tracer kinetic models, which can be modified and simplified for particular application. Selective radioligands are available for the various transmitter systems, by which the distribution of these receptors in the normal brain and changes in receptor binding during various physiologic activities or resulting from pathologic conditions can be visualized. The quantitative imaging for several receptors has gained clinical importance-for example, dopamine (D2)) receptors for differential diagnosis of movement disorders and for assessment of receptor occupancy by neuroleptics drugs; serotonin (5-hydroxytryptamine, 5-HT) receptors and the 5-HT transporter in affective disorders and for assessment of activity of antidepressants; nicotinic receptors and acetylcholinesterase as markers of cognitive and memory impairment; central benzodiazepine-binding sites at the gamma-aminobutyric acid A (GABAA) receptor complex as markers of neuronal integrity in neurodegenerative disorders, epilepsy, and stroke and as the site of action of benzodiazepines; peripheral benzodiazepine receptors as indicators of inflammatory changes; opioid receptors detecting increased cortical excitability in focal epilepsy but also affected in perception of and emotional response to pain; and several receptor systems affected in drug abuse and craving. Further studies of the various transmitter/receptor systems and their balance and infraction will improve our understanding of complex brain functions and will provide more insight into the pathophysiology of neurologic and psychiatric disease interaction.
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PMID:Brain receptor imaging. 1645 37

Increasing interest has been directed to role of pharmaceuticals in the recovery of cerebrovascular events. However, only few scientific studies are available to date, and further research is needed. Amphetamine is the most extensively studied drug shown to promote recovery of function, although clinical data have lead to conflicting results. Other psychostimulants drugs have been proposed, as levodopa or methylphenidate, even if published data are still few. Recently, two studies have been published about the positive role of cholinesterase inhibitor donepezil on stroke recovery. However, such data must still be confirmed by randomized controlled trials. Antidepressant drugs have shown to be effective not only in improving depressive symptoms in stroke patients, but also in decreasing, although partially, the negative impact of poststroke depression on functional outcome. Serotoninergic agents may have a role in improving stroke recovery, in a fashion that is not dependent on their primary antidepressant activity. Last, it is important to be aware that certain drugs as clonidine, prazosin, dopamine receptor antagonists, benzodiazepines, phenytoin, and phenobarbital could have a detrimental effect on the poststroke recovery.
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PMID:New developments on drug treatment rehabilitation. 1683 44

Novel and diverse functions of glial cells are currently the focus of much attention [A. Volterra and J. Meldolesi (2005) Nature Rev. 6, 626-640]. Here we present evidence that rat astroglia release acetylcholinesterase (AChE) as part of their response to hypoxic damage. Exposure of astroglia to tert-butyl hydroperoxide, and hence oxidative stress, subsequently leads to a switching in mRNA from the classical membrane-bound T-AChE to a preferential increase in the splice variant for a soluble form, R-AChE, This change in expression is reflected in increased perinuclear and reduced cytoplasmic AChE staining of the insulted glial cells, with a concomitant and marked increase in extracellular secretion that peaks at 1 h post-treatment. An analogous increase in R-AChE, over a similar time scale, occurs in response to psychological stress [D. Kaufer et al. (1998) Nature 93, 373-377], as well as to head injury and stroke [E. Shohami et al. (1999) J. Neurotrauma 6, 365-76]. The data presented here suggest that glial cells may be key chemical intermediaries in such situations and, perhaps more generally in pathological conditions involving oxidative stress, such as neurodegeneration.
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PMID:Astroglia up-regulate transcription and secretion of 'readthrough' acetylcholinesterase following oxidative stress. 1690 48

Vascular dementia (VaD) is the second leading cause of dementia and is often underdiagnosed. Stroke is the leading cause of VaD, although it may also develop secondary to a variety of other cerebrovascular or cardiovascular conditions. Currently, no drugs are approved for the treatment of VaD. However, because cholinergic deficits have been found in patients with VaD, similar to those found in patients with Alzheimer disease (AD), it is believed that cholinesterase inhibitors, which are indicated for the treatment of mild to moderate AD, may also provide benefit for patients with VaD. Clinical trials of donepezil, galantamine, and rivastigmine have supported this idea, although as yet, large-scale, prospective studies in VaD have only been reported for donepezil. Donepezil was shown to provide benefits in cognition, global function, and activities of daily living compared with placebo. The N-methyl-D-aspartate receptor antagonist memantine may also provide some cognitive benefit in VaD, particularly in patients with more advanced disease. These data suggest that antidementia drugs currently used for treatment of AD should be considered for treatment of VaD as well.
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PMID:Use of antidementia agents in vascular dementia: beyond Alzheimer disease. 1703 61

Cognitive impairment of any severity associated with cerebrovascular damage is defined as vascular cognitive impairment as proposed by O'Brien. This is a heterogeneous syndrome with many subtypes, the most prevalent being vascular cognitive impairment without dementia. Neuropathological studies confirm that cerebrovascular disease and Alzheimer's disease frequently coexist. Diagnosis depends on criteria for dementia and vascular pathologies. Brain imaging is an important diagnostic tool. Although there is no approved intervention specifically for vascular cognitive impairment, general treatments (such as antiplatelet and antihypertensives) aimed at the prevention and management of stroke are used. Evidence from randomised, placebo-controlled studies of cholinesterase inhibitors for vascular dementia suggests that there may be beneficial effects for cognitive function, and clinical global impression is more favourable for the cholinesterase inhibitors compared with placebo. The effect of memantine also seems to be modest and similar to the effect that is demonstrated in patients with Alzheimer's disease. The accumulated evidence is not as comprehensive as that which exists for Alzheimer's disease. The cholinesterase inhibitors and memantine have not been extensively studied in vascular cognitive impairment without dementia. For the purposes of this review, the authors focus on interventions that have been evaluated by randomised controlled trials.
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PMID:Investigational treatment for vascular cognitive impairment. 1746 38

Alzheimer's disease (AD) is characterized by an extensive loss of cholinergic neurons, and their cortical projections, from the basal forebrain area. The resulting reduction in cholinergic activity is associated with decreased levels of the neurotransmitter acetylcholine (ACh), decreased activity of acetylcholinesterase (AChE), choline acetyltransferase (ChAT), and increased butyrylcholinesterase (BChE) activity. In the present study, we investigated whether the BCHE, ACHE, and CHAT genes were associated with AD and the possibility of a synergistic effect with APOE-epsilon4 in a Sardinian sample. AD patients (n = 158), exclusively of Sardinian ancestry, were recruited from the Division of Geriatrics Local Health Agency 8 and Unit of Clinical Pharmacology, Department of Neurosciences, University of Cagliari. Patients were diagnosed according to DSM-IV, and National Institute of Neurologic and Communicative Disorders and Stroke-AD and Related Disorders Association (NINCDS-ADRDA) criteria for possible or probable AD. Cognitive screening was performed by means of Mini-Mental State Examination (MMSE). Healthy controls (n = 118) of Sardinian ancestry were recruited from religious and sport associations. All patients and control subjects gave informed consent for participation in the study. Single nucleotide polymorphism (SNP) analysis was performed by PCR/RFLP or the TaqMan 5' exonuclease method. Our study confirms the association between APOE epsilon4 allele and AD (P < 0.000). No significant differences were observed in allele and genotype frequencies of BCHE, ACHE, and CHAT between AD and controls. Haplotype analysis of ACHE SNPs did not reveal a significant association between ACHE and AD. Our results suggest that the AChE, ChAT, and BChE polymorphisms do not constitute a major genetic risk factor for susceptibility to AD in a Sardinian population.
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PMID:Alzheimer's disease: case-control association study of polymorphisms in ACHE, CHAT, and BCHE genes in a Sardinian sample. 1750 75


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