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Biomedical subjects

L Parnetti

Publications and source records attributed to L Parnetti.

At least 37 records · Page 2Linked to original sources
PubMed2001

Activation of complement and contact system in Alzheimer's disease.

beta-Amyloid protein (betaA) has been implicated in the pathogenesis of Alzheimer's disease (AD) because of its neurotoxicity and ability to trigger a local inflammatory response. Although assembly of betaA in particular aggregates seems to be crucial event in AD pathogenesis, soluble, non-fibrillar betaA may also be involved. Non-fibrillar betaA1-42, and truncated peptide 1-28, induced dose-dependent activation of C4 sparing C3. The mechanism of C4 activation was not dependent on C1q, because non-fibrillar betaA can still activate C4 in plasma genetically deficient in C1q. A C1q independent mechanism of complement classical pathway activation could be via the activation of contact/kinin system. The possible involvement of contact system in AD is suggested by the finding that this system is massively activated in CSF of AD patients. The mechanism of activation of contact system could be the result of an anionic interaction of residues within the region 1-11 of betaA1-42 with factor XII, and of kallikrein generation. Concomitant incubation of a small cationic peptide (lysine4) with betaA abrogated its ability to trigger the cleavage of high molecular weight kininogen. In vivo, prevention of contact system activation beside the reduction of kallikrein generation, can also decrease the activation of complement system and the release of interleukin-6, both factors being considered to play an important role in the inflammatory reactions in AD brain.

Alzheimer Disease↗
PubMed2001

Choline alphoscerate in cognitive decline and in acute cerebrovascular disease: an analysis of published clinical data.

This paper has reviewed the documentation on the clinical efficacy of choline alphoscerate, a cholinergic precursor, considered as a centrally acting parasympathomimetic drug in dementia disorders and in acute cerebrovascular disease. Thirteen published clinical trials, examining in total 4054 patients, have evaluated the use of choline alphoscerate in various forms of dementia disorders of degenerative, vascular or combined origin, such as senile dementia of the Alzheimer's type (SDAT) or vascular dementia (VaD) and in acute cerebrovascular diseases, such as transitory ischemic attack (TIA) and stroke. Analysis has assessed the design of each study, in particular with respect to experimental design, number of cases, duration of treatment and tests used to evaluate drug clinical efficacy. Most of the ten studies performed in dementia disorders were controlled trials versus a reference drug or placebo. Overall, 1570 patients were assessed in these studies, 854 of which in controlled trials. As detected by validated and appropriate tests, such as Mini Mental State Evaluation (MMSE) in SDAT and Sandoz Clinical Assessment Geriatric (SCAG) in VaD, administration of choline alphoscerate significantly improved patient clinical condition. Clinical results obtained with choline alphoscerate were superior or equivalent to those observed in control groups under active treatment and superior to the results observed in placebo groups. Analysis stresses the clear internal consistency of clinical data gathered by different experimental situations on the drug effect, especially with regard to the cognitive symptoms (memory, attention) characterising the clinical picture of adult-onset dementia disorders. The therapeutic usefulness of choline alphoscerate in relieving cognitive symptoms of chronic cerebral deterioration differentiates this drug from cholinergic precursors used in the past, such as choline and lecithin. Three uncontrolled trials were performed with choline alphoscerate in acute cerebrovascular stroke and TIA, totalling 2484 patients. The results of these trials suggest that this drug might favour functional recovery of patients with cerebral stroke and should be confirmed in future investigations aimed at establish the efficacy of the drug in achieving functional recovery of patients with acute cerebrovascular disease.

Cerebrovascular Disorders↗
PubMed2001

Cerebrospinal fluid acetylcholinesterase activity after long-term treatment with donepezil and rivastigmina.

At present acetylcholinesterase (AChE) inhibitors (AChEIs) represent the only reliable therapeutic resource for symptomatic treatment of Alzheimer Disease (AD). This study was designed to assess the effects of 6-12 month treatment with AChEIs donepezil and rivastigmine on cerebrospinal fluid (CSF) AChE and butyrylcholinesterase (BuChE) activity in AD patients. The pattern of AChE isoforms (G4, G1, G2) before and after treatment was investigated as well. In AD patients treated with donepezil a significant increase of CFS AChE activity was observed, whereas treatment with rivastigmine induced a significant decrease of AChE activity. Both drugs did not change BuChE activity and tended to restore the physiological pattern of AChE isoform. The possible significance of the influence of AChEIs on CSF AChE activity and isoforms is discussed.

Acetylcholinesterase↗
PubMed2001

Pharmacological treatment of non-cognitive disturbances in dementia disorders.

Behavioral and psychological symptoms of dementia (BPSD) occur in 50-90% of patients with Alzheimer's disease (AD). They cause premature institutionalization, increased costs of care and significant loss of quality-of-life for the patient and his/her family and caregivers. Non-pharmacological interventions are first-line in dealing with milder BPSD, while for moderate to severe BPSD, medication is clearly indicated in conjunction with non-pharmacological interventions. An imbalance of different neurotransmitters (acetylcholine, dopamine, noradrenaline, serotonin) has been proposed as the neurochemical correlate of BPSD. An involvement of some specific brain regions responsible for emotional activities (parahippocampal gyrus, dorsal raphe, locus coeruleus) and cortical hypometabolism have been suggested to contribute to BPSD. Atypical or novel antipsychotic drugs represent the reference drugs for treating BPSD. Among these, risperidone is considered as a drug of choice. Also, selective serotonin reuptake inhibitors (SSRIs) are useful in the treatment of BPSD.

Alzheimer Disease↗
PubMed2001

Mild hyperhomocyst(e)inemia: a possible risk factor for cervical artery dissection.

BACKGROUND AND PURPOSE: The pathogenesis of cervical artery dissection (CAD) remains unknown in most cases. Hyperhomocyst(e)inemia [hyperH(e)], an independent risk factor for cerebrovascular disease, induces damage in endothelial cells in animal cell culture. Consecutive patients with CAD and age-matched control subjects have been studied by serum levels of homocyst(e)ine and the genotype of 5,10-methylenetetrahydrofolate reductase (MTHFR). METHODS: Twenty-six patients with CAD, admitted to our Stroke Unit (15 men and 11 women; 16 vertebral arteries, 10 internal carotid arteries), were compared with age-matched control subjects. All patients underwent duplex ultrasound, MR angiography, and/or conventional angiography. RESULTS: Mean plasma homocyst(e)ine level was 17.88 micromol/L (range 5.95 to 40.0 micromol/L) for patients with CAD and 6.0+/-0.99 micromol/L for controls (P:<0.001). The genetic analysis for the thermolabile form of MTHFR in CAD patients showed heterozygosity in 54% and homozygosity in 27%; comparable figures for controls were 40% (P:=0.4) and 10% (P:=0.1), respectively. CONCLUSIONS: Mild hyperH(e) might represent a risk factor for cervical artery dissection. The MTHFR mutation is not significantly associated with CAD. An interaction between different genetic and environmental factors probably takes place in the cascade of pathogenetic events leading to arterial wall damage.

Adolescent↗
PubMed2000

Cerebrospinal fluid pyruvate levels in Alzheimer's disease and vascular dementia.

Increased amounts of CSF pyruvate and lactate were found in patients with AD and patients with vascular dementia (VaD). In the AD group, CSF pyruvate values did not show any overlap with those obtained in controls; within the VaD group, the highest values were observed in possible VaD cases. A significant correlation between the severity of dementia and these biochemical parameters was also observed in both AD and possible VaD. The similarities of CSF pyruvate patterns observed in AD and possible VaD patients implicate a neurodegenerative component in this VaD subgroup.

Aged↗
PubMed2000

Therapeutic options in dementia.

Dementia is the final common path of various pathogenetic mechanisms that may lead to a number of different clinical forms, with primary degenerative and vascular dementias accounting for more than 80% of cases. Dementia is a complex clinical condition that includes cognitive, personality, and behavioral changes. Therefore a therapeutic approach to dementia should be based from the beginning on a comprehensive intervention plan, both pharmacological and nonpharmacological. This should not be aimed at obtaining a complete (impossible) recover but at achieving the best day-to-day management of a chronic, progressive, disabling disease involving numerous domains and showing impairments with varying rates of progression. Deterioration in functional abilities of daily living has a major impact on the quality of life of those suffering from dementia, and this is a critical predictor for institutionalization. Increasingly necessary for optimizing intervention strategies are studies to: (a) measure changes in functional abilities over the course of dementia (namely Alzheimer's disease), (b) evaluate the relationship between functional abilities and cognition, and (c) quantify the effect of various therapeutic approaches on functional decline. Symptomatic drugs affecting cognitive abilities and psychoactive drugs for behavioral disturbances should be considered. For the cognitive domain positive results have been obtained with acetylcholinesterase inhibitors. Among the psychoactive drugs indicated for behavioral disorders, significant improvement in terms of both efficacy and tolerability can be expected from the use of new antipsychotic drugs.

Antipsychotic Agents↗
PubMed2000

Alpha-dihydroergocryptine in the treatment of de novo parkinsonian patients: results of a multicentre, randomized, double-blind, placebo-controlled study.

INTRODUCTION: A multicentre, randomized, double-blind, placebo-controlled, parallel group study was carried out in 123 patients suffering from never treated (de novo) idiopathic Parkinson's disease (PD). The aim of the study was to confirm the efficiency and safety of alpha-dihydroergocryptine (alpha-DHEC) given as monotherapy in the symptomatic treatment of PD. The total score of the Unified Parkinson's Disease Rating Scale (UPDRS) was identified as the efficacy target variable. PATIENTS AND METHODS: Sixty-two patients (32 males, 30 females, mean age +/- SD 64 +/- 10) were randomized to alpha-dihydroergocryptine and 61 (30 males, 31 females, mean age 63.8 +/- 9.1) to placebo. According to the experimental design, a 18-month double-blind phase vs placebo was followed. Two interim analyses were planned both at the 3rd and 12th month of treatment, in order to avoid continuation on placebo, if clear differences between groups were found (stopping criterium: nominal significance level equal to 0.022 in the analysis of the target variable). Analysis of variance was performed both on the per protocol (PP) and intent-to-treat (ITT) sample. RESULTS: The results on the first interim analysis showed significant differences between treatment groups of the UPDRS total score both in the ITT (115 patients, alpha-DHEC: No. 56; placebo: No. 59; P=0.019) and PP (96 patients, alpha-DHEC: No. 46; placebo: No. 50; P=0.001) sample, why the trial was stopped. At the time of stopping the trial, 73 patients (alpha-DHEC: No. 37; placebo: No. 36) had reached the 6-month observation visit; the analysis carried out on this subset of patients confirmed the efficacy of alpha-dihydroergocryptine in early PD and the correctness of the decision to stop. The incidence of adverse drug reactions (ADR) did not differ between alpha-dihydroergocryptine and placebo recipients, gastrointestinal complaints being the most frequent. CONCLUSION: The results indicate that alpha-dihydroergocryptine is safe and effective in improving symptoms of de novo parkinsonian patients.

Dihydroergotoxine↗
PubMed1999

Radioligand binding assay of M1-M5 muscarinic cholinergic receptor subtypes in human peripheral blood lymphocytes.

Analysis of lymphocyte muscarinic cholinergic receptors using quantitative techniques such as radioligand binding assay is made difficult due to the low density of these sites and the lack of subtype-specific selectivity of most available muscarinic ligands. In this study, a combined kinetic and equilibrium labeling technique recently developed for brain tissue was used for labeling the five muscarinic cholinergic receptor subtypes in intact human peripheral blood lymphocytes. No specific muscarinic M1 receptor binding was detectable in human peripheral blood lymphocytes using [3H]-pirenzepine as a ligand. Labeling of M2-M5 muscarinic receptors using [3H]N-methyl-scopolamine (NMS) by occluding various receptor subtypes with muscarinic antagonist and mamba venom resulted in the labeling of M2-M5 receptors in brain as well as in human peripheral blood lymphocytes. The relative density of different receptor subtypes was M3 > M5 > M4 > M2. The development of a reproducible technique for assaying muscarinic cholinergic receptor subtypes expressed by human peripheral blood lymphocytes may contribute to clarify their role in lymphocyte function.

Adult↗
PubMed1999

Stroke and atrial fibrillation: is stroke prevention treatment appropriate beforehand? SAFE I Study Investigators.

OBJECTIVE: To undertake a pilot study before conducting a large European multicentre prospective study, to determine the proportion of patients with atrial fibrillation who were not receiving antithrombotic treatment before stroke onset, and their characteristics. DESIGN AND PATIENTS: The stroke in atrial fibrillation ensemble (SAFE) I study was an observational study conducted in 213 patients with atrial fibrillation consecutively admitted in 1997 to three European centres for an acute stroke or transient ischaemic attack (TIA). It was determined whether they were receiving prior antithrombotic treatment. RESULTS: Atrial fibrillation was known before stroke in 148 patients (69.5%). Of 213 patients, 34 (16.0%) were receiving anticoagulation treatment before stroke, but only six had an international normalised ratio between 2. 0 and 3.5; 65 (30.5%) were receiving antiplatelet treatment; and three (1.4%) were receiving both anticoagulation and antiplatelet treatment. Of 137 patients eligible for oral anticoagulation, 108 (78.8%) did not receive treatment. Of 142 patients eligible for any antithrombotic treatment, 62 (43.7%) were not treated. The logistic regression analysis, assuming anticoagulation treatment as a dependent variable, found digoxin treatment, absence of arterial hypertension, mitral stenosis, and cardioversion as independent factors. Assuming any antithrombotic treatment as a dependent variable, previously known atrial fibrillation, lower age, being a non-smoker, and absence of arterial hypertension were found to be independent factors. CONCLUSION: More than half of the patients with atrial fibrillation admitted for acute stroke or TIA were not receiving any antithrombotic treatment beforehand. New onset atrial fibrillation and contraindications account for a minority of non-prescriptions; thus, other reasons should be identified to improve stroke prevention in the community.

Adult↗
PubMed1999

White matter changes in stroke patients. Relationship with stroke subtype and outcome.

White matter changes (WMC), detected by imaging techniques, are frequent in stroke patients. The aim of the study was to determine how WMC relate to stroke subtypes and to stroke outcome. We made a systematic Medline search for articles appearing with two of the following key words: either 'WMC or white matter lesions or leukoencephalopathy or leukoaraiosis' and 'stroke or cerebral infarct or cerebral hemorrhage or cerebrovascular disease or transient ischemic attack (TIA)'. WMC, as defined radiologically, are present in up to 44% of patients with stroke or TIA and in 50% of patients with vascular dementia. WMC are more frequent in patients with lacunar infarcts, deep intracerebral hemorrhages, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and cerebral amyloid angiopathy. After an acute ischemic stroke, WMC are associated with a higher risk of death or dependency, recurrent stroke of any type, cerebral bleeding under anticoagulation, myocardial infarction, and poststroke dementia. WMC in stroke patients are often associated with small-vessel disease and lead to a higher risk of death, and poor cardiac and neurological outcome. However, several questions remain open and need further investigations.

Age Factors↗
PubMed1999

Pathophysiology of vascular dementia and white matter changes.

Vascular dementia (VaD) can be defined as a dementia syndrome likely to be the consequence of lesions of the brain, vascular in origin, irrespective of their ischemic, hemorrhagic or hypoxic nature. Six subtypes (1) multi-infarct dementia, (2) strategic single infarct dementia, (3) small-vessel disease with dementia, (4) hypoperfusion dementia, (5) hemorrhagic dementia and other VaD, have been proposed, indicating the broad clinical spectrum of this disorder. Major determinants of the dementia syndrome are (i) stroke characteristics--i.e., lacunar infarcts, localization in the left hemisphere and/or in strategic regions--, (ii) white matter changes frequently seen in stroke patients, especially in those who have lacunes or deep hemorrhages, represent a strong predictor for risk of dementia--and (iii) associated Alzheimer pathology--Alzheimer and vascular lesions are frequently associated. Finally, it should also be considered the role of the summation of various lesion types, since many cases of dementia occurring in stroke patients are multifactorial.

Dementia, Multi-Infarct↗
PubMed1998

Activation of the contact system in cerebrospinal fluid of patients with Alzheimer disease.

Several converging lines of evidence suggest that beta-amyloid and inflammation may be linked in the pathogenesis of Alzheimer disease (AD), but the mechanism of beta-amyloid neurotoxicity is unclear. In this study, by demonstrating that high molecular weight kininogen may be massively cleaved in the cerebrospinal fluid (CSF) of patients with AD, we provide evidence of the potential involvement of the contact system in the inflammatory processes taking place in this disease. In the CSF of patients with neuroimmune inflammatory disease (multiple sclerosis, chronic inflammatory demyelinating polyneuropathy), there was no evidence of increased cleavage of high molecular weight kininogen, suggesting that this finding may be characteristic of the Alzheimer brain. The data obtained from in vitro experiments seem to indicate that the cleavage of high molecular weight kininogen in vivo may be the result of the interaction of beta-amyloid with factor XII and of kallikrein generation. The actual relevance of such a phenomenon remains to be established in vivo. However, the demonstration that the contact system may be activated in the brains of Alzheimer patients points to the potential involvement of the kallikrein-kinin system in the inflammatory process of this disease.

Aged↗
PubMed1997

Apolipoprotein-E genotype in normal aging, age-associated memory impairment, Alzheimer's disease and vascular dementia patients.

Apolipoprotein-E (Apo-E) genotype and allele frequencies were evaluated in patients with late-onset probable Alzheimer's disease (LOAD; n = 64), early-onset probable Alzheimer's disease (EOAD; n = 32), possible Alzheimer's disease (pAD; n = 44), vascular dementia (VD; n = 12), age-associated memory impairment (AAMI; n = 15) and 40 healthy age-matched controls. APO-E was performed by polymerase chain reaction products digested by the restriction enzyme HhaI. A statistically significant increase of epsilon4 frequency was found in LOAD as compared to the other groups, and in pAD with respect to controls, while VD and AAMI groups did not disclose any difference as regards to control subjects. Multivariate analysis showed a significant association of epsilon4 with female gender. Our results confirm the increased frequency of epsilon4 in both probable and possible LOAD, failing to show a similar trend in VD and AAMI.

Adult↗
PubMed1997

Vascular dementia Italian sulodexide study (VA.D.I.S.S.). Clinical and biological results.

In order to evaluate the biological effects on some haemostasis factors of antithrombotic-hemorheological treatments on patients with vascular dementia, a multicenter, randomized, double-blind, double-dummy, study comparing sulodexide (Sdx, 50 mg bid orally for 6 months) and pentoxifylline (Ptx, 400 mg tid orally for six months) was carried out. Eighty-six patients, 46 in Sdx group, 40 in Ptx group, fulfilling the NINDS-AIREN criteria for probable vascular dementia were evaluated. Plasma fibrinogen levels showed a significant reduction in both groups, in patients with high basal levels (> or = 350 mg/dl), the reduction being earlier in Sdx group (2nd month of therapy) than in Ptx group (4th month of therapy). In Sdx group a significant reduction in factor VII-Ag (baseline 102.8 U/dl; 6th month 90.1 U/dl) was also observed. Both drugs induced a slight reduction in activated factor VII levels as well. A parallel improvement of G.B.S. Rating Scale for dementia scores was observed in Sdx group. These results seem to indicate that sulodexide treatment can have positive effects in vascular dementia.

Administration, Oral↗