A new kind of flow-through sensor for atropine has been studied. It exhibits Nernstian response for atropine with a slope of 54 +/- 1 mV/decade over the concentration range of 0.02-200 mmol/L at pH 5-8. The sensitivity coefficients of common compounds were determined. Only bromo-geramine, clonidine, strychnine and amantadine showed remarkable interference. Direct potentiometry for determination of atropine showed an average recovery of 99.2% and a relative standard deviation of 1.3%. It has been used in flow injection analysis (FIA) of atropine, anisodamine and scopolamine and belladonna preparations. Rate of analysis of as high as 60-100 samples/h was achieved.
A total of 52 healthy, adult volunteers were randomly assigned to five treatment groups to be treated twice daily for 4 days with 100 mg of amantadine, 100 mg of rimantadine, 4 mg of chlorpheniramine or placebo alone, or 100 mg of amantadine in combination with chlorpheniramine. The results of tests measuring performance on tasks of attention, reasoning, and memory were unaffected by treatment. Subjective side effects in recipients of amantadine, rimantadine, and chlorpheniramine were comparable and minimal. Side effects appeared to be enhanced in subjects receiving both amantadine and chlorpheniramine.
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Twenty-five patients were included. The memantine and placebo group did not differ significantly in terms of stride length. However, in the memantine group, we observed significantly better results (vs placebo) for the overall UPDRS score (F(1,21)=4.9; p=0.039(-1)) and its axial subscore (F(1,21)=7.2; p=0.014(-1.1)), axial hypertonia, the axial and overall DRS and axial strength.
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Ts65Dn (TS) mice exhibit several phenotypic characteristics of human Down syndrome, including an increased brain expression of amyloid-beta protein precursor (AbetaPP) and cognitive disturbances. Aberrant N-methyl-D-aspartate (NMDA) receptor signaling has been suspected in TS mice, due to an impaired generation of hippocampal long-term potentiation (LTP). Memantine, an uncompetitive NMDA receptor antagonist approved for the treatment of moderate to severe Alzheimer's disease, is known to normalize LTP and improve cognition in transgenic mice with high brain levels of AbetaPP and amyloid-beta protein. It has recently been demonstrated that acute injections of memantine rescue performance deficits of TS mice on a fear conditioning test. Here we show that oral treatment of aged TS mice with a clinically relevant dose of memantine (30 mg/kg/day for 9 weeks) improved spatial learning in the water maze task and slightly reduced brain AbetaPP levels. We also found that TS mice exhibited a significantly reduced granule cell count and vesicular glutamate transporter-1 (VGLUT1) labeling compared to disomic control mice. After memantine treatment, the levels of hippocampal VGLUT1 were significantly increased, reaching the levels observed in vehicle treated-control animals. Memantine did not significantly affect granule cell density. These data indicate that memantine may normalize several phenotypic abnormalities in TS mice, many of which--such as impaired cognition--are also associated with Down syndrome and Alzheimer's disease.
Major advances in molecular virology have led to the development of new antiviral compounds. These drugs include ribavirin, used in the treatment of severe respiratory syncytial virus infection in children; amantadine, used in the prophylaxis and treatment of influenza A infection; acyclovir, used in a variety of herpesvirus infections, including primary gingivostomatitis, genital herpes and herpes zoster; ganciclovir, used in the treatment of retinitis due to cytomegalovirus, and zidovudine, used in the prophylaxis and treatment of human immunodeficiency virus infection.
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The current clinical view on pharmacological treatment and the Croatian reality regarding approved antidementia drugs is presented. Dementia is a syndrome of high incidence and Alzheimer's disease is the most common cause of dementia. New data show that dementia prevalence will nearly double every 20 years, and we believe that current estimated number of persons with dementia (PWD) for Croatia is more than 80,000. The standard treatment with antidementia drugs is unavailable in Croatia, for the majority of PWD, because antidementia drugs are not on the reimbursement list, although Croatian algorithm for psychopharmacological treatment and Alzheimer Disease Societies Croatia recommend early and adequate treatment. Alzheimer's dementia is becoming a world's health priority in 21st century, so we strongly believe that antidementia drugs should be reimbursed in Croatia.
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Long-term use of memantine appears safe and tolerable. Future randomized studies with longer follow-up are necessary to establish efficacy of memantine for the treatment of HIV-associated cognitive impairment.
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Axonal trauma leads to a series of pathologic events that can culminate in neuronal death. Although the precise mechanisms of retinal ganglion cell death after optic nerve crush in the rat model have not been elucidated, glutamate antagonists can protect retinal ganglion cells after optic nerve axotomy. We therefore explored whether a glutamate congener was toxic if applied directly within the optic nerve, or if toxicity depended upon an interaction at the cell body level. NMDA reduced retinal ganglion cell survival when applied directly into the rat optic nerve. Glutamate can be toxic if administered within the optic nerve; a direct effect at the cell body is not necessary. Future work will help to additionally unravel the steps by which axotomy induces excitotoxic damage to ganglion cells, and perhaps indicate protective interventions.
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Freezing of gait (FOG) is frequently considered as one of the dopamine-resistant motor symptoms of Parkinsonism. Recent studies have clearly demonstrated that the Off-related FOG is improved by levodopa (L-dopa) or entacapone treatment. L-dopa can decrease duration of each FOG episode as well as its frequency. On-related FOGs are not common and difficult to diagnose. Only in the most advanced stages of the disease, FOGs are resistant to treatment as many other symptoms. Off-related FOGs are likely to be improved by dopamine agonists (DAs), but this has never been looked at systematically. In contrast, DA treatment might provoke FOG, and in two pivotal studies when DAs were compared to L-dopa in early stages of Parkinson's disease, the DA-treated arms experienced more FOGs. MAO-B inhibitors (selegiline and rasagiline) can decrease FOG frequency or severity, but its clinical significance is still unknown. L-Threo-DOPS has been reported to have a symptomatic beneficial effect in patients with pure freezing syndrome, but small-scale, controlled trials in Parkinson's disease could not support those early observations. Botulinum toxin injected into the calf muscles has been suggested to have a symptomatic benefit. However, double-blind, prospective studies could not support that early observation and increased fall risk in the injected patients has put this direction of treatment on hold. The potential benefit of amantadine, antidepressive drugs, acetylcholine esterase inhibitors, and methylphenidate on FOG has been studied in small-scale studies, and there is a need for prospective studies to understand the future role of those drugs.
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From a societal perspective, treatment with cholinesterase inhibitors or memantine was more effective but also more costly than standard care for mild to moderate vascular dementia. The donepezil 10 mg strategy was the most cost-effective and also dominated the other alternatives.
Every year, nearly 200,000 patients undergo radiation for brain tumors. For both patients and caregivers the most distressing adverse effect is impaired cognition. Efforts to protect against this debilitating effect have suffered from inadequate understanding of the cellular mechanisms of radiation damage. In the past it was accepted that radiation-induced normal tissue injury resulted from a progressive reduction in the survival of clonogenic cells. Moreover, because radiation-induced brain dysfunction is believed to evolve over months to years, most studies have focused on late changes in brain parenchyma. However, clinically, acute changes in cognition are also observed. Because neurons are fully differentiated post-mitotic cells, little information exists on the acute effects of radiation on synaptic function. The purpose of our study was to assess the potential acute effects of radiation on neuronal function utilizing ex vivo hippocampal brain slices. The cellular localization and functional status of excitatory and inhibitory neurotransmitter receptors was identified by immunoblotting. Electrophysiological recordings were obtained both for populations of neuronal cells and individual neurons. In the dentate gyrus region of isolated ex vivo slices, radiation led to early decreases in tyrosine phosphorylation and removal of excitatory N-methyl-D-aspartate receptors (NMDARs) from the cell surface while simultaneously increasing the surface expression of inhibitory gamma-aminobutyric acid receptors (GABA(A)Rs). These alterations in cellular localization corresponded with altered synaptic responses and inhibition of long-term potentiation. The non-competitive NMDAR antagonist memantine blocked these radiation-induced alterations in cellular distribution. These findings demonstrate acute effects of radiation on neuronal cells within isolated brain slices and open new avenues for study.
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The diagnosis of Parkinson disease in a symptomatic individual is based solely on the clinical findings of tremor, rigidity, and bradykinesia. A good response to levodopa and asymmetric onset of limb involvement are generally regarded as supporting diagnostic features. The cardinal pathologic feature of Parkinson disease is the loss of dopaminergic neurons in the substantia nigra with intracytoplasmic inclusions (Lewy bodies) in the remaining, intact nigral neurons. The genes that are mutated in some of the inherited forms of Parkinson disease have been identified. Molecular genetic testing for some of these genes is clinically available either individually or as multi-gene panels. Note: Although currently available genetic tests aid in the diagnosis of Parkinson disease in symptomatic individuals, they are not useful in risk prediction for asymptomatic individuals with no family history of Parkinson disease.
A flow cytometric virus-binding assay that directly visualizes the binding and entry of infectious pancreatic necrosis virus (IPNV), infectious haematopoietic necrosis virus (IHNV) and virus haemorrhagic septicaemia virus (VHSV) to several cell lines was established. The highest efficiency of binding was shown by the BF-2 cell line and this was used to study, at the attachment level, the interactions of these cells with salmonid fish viruses in coinfections, and to further determine if the earliest stage of the viral growth cycle could explain the previously described loss of infectivity of IHNV when IPNV is present. Our results demonstrated that IPNV binds to around 88% of cells either in single or dual infections, whereas IHNV attachment always decreased in the presence of any of the other viruses. VHSV binding was not affected by IPNV, but coinfection with IHNV reduced the percentage of virus-binding cells, which suggests competition for viral receptors or co-receptors. Internalization of the adsorbed IHNV was not decreased by coinfection with IPNV, so the hypothetical competence could be restricted to the binding step. Treatment of the cells with antiviral agents, such as amantadine or chloroquine, did not affect the binding of IPNV and VHSV, but reduced IHNV binding by more than 30%. Tributylamine affected viral binding of the three viruses to different degrees and inhibited IPNV or IHNV entry in a large percentage of cells treated for 30 min. Tributylamine also inhibited IHNV cytopathic effects in a dose-dependent manner, decreasing the virus yield by 4 log of the 50% endpoint titre, at 10 mm concentration. IPNV was also inhibited, but at a lower level. The results of this study support the hypothesis that IHNV, in contrast to VHSV or IPNV, is less efficient at completing its growth cycle in cells with a simultaneous infection with IPNV. It can be affected at several stages of viral infection and is more sensitive to the action of antiviral compounds.
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Advances in the diagnosis and multi-modality treatment of cancer have increased survival rates for many cancer types leading to an increasing load of long-term sequelae of therapy, including that of cognitive dysfunction. The cytotoxic nature of chemotherapeutic agents may also reduce neurogenesis, a key component of the physiology of memory and cognition, with ramifications for the patient's mood and other cognition disorders. Similarly radiotherapy employed as a therapeutic or prophylactic tool in the treatment of primary or metastatic disease may significantly affect cognition. A number of emerging pharmacotherapies are under investigation for the treatment of cognitive dysfunction experienced by cancer patients. Recent data from clinical trials is reviewed involving the stimulants modafinil and methylphenidate, mood stabiliser lithium, anti-Alzheimer's drugs memantine and donepezil, as well as other agents which are currently being explored within dementia, animal, and cell culture models to evaluate their use in treating cognitive dysfunction.
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788 cases with parkinsonism archived at the Queen Square Brain Bank for Neurological Diseases were identified for study. Patients had not been given standardised antemortem assessments. Clinical records were assessed for reports of VH. The incidence of VH in pathologically diagnosed cases was calculated, and factors affecting onset of VH were investigated.
The approved treatments for Alzheimer's disease (AD) exploit mainly a symptomatic approach based on the use of cholinesterase inhibitors or N-methyl-D-aspartate (NMDA) receptor antagonists. Natural antioxidant compounds, able to pass through the blood-brain barrier (BBB), have been extensively studied as useful neuroprotective agents. A novel approach towards excitotoxicity protection and oxidative stress associated with excess β amyloid (Aβ) preservation in AD is represented by selective glutamatergic antagonists that possess as well antioxidant capabilities. In the present work, GSH (1) or (R)-α-lipoic acid (LA) (2) have been covalently linked with the NMDA receptor antagonists memantine (MEM). The new conjugates, proposed as potential antialzheimer drugs, should act both as glutamate receptor antagonists and radical scavenging agents. The physico-chemical properties and "in vitro" membrane permeability, the enzymatic and chemical stability, the demonstrated "in vitro" antioxidant activity associated to the capacity to inhibit Aβ(1-42) aggregation makes at least compound 2 a promising candidate for treatment of AD patients.
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Investigations from abroad and from Denmark show that epidemics of influenza are not only accompanied by considerable morbidity but also by considerable excess mortality and a sizable increase in the number of admissions to hospital. The increases in the number of deaths comprise 170-320 per million of the population per epidemic. The excess mortality occurs primarily among individuals with chronic pulmonary and circulatory disease and may be very great in nursing homes and similar institutions. Influenza vaccination will, in general, provide protection of approximately 70% and does not cause noteworthy side effects. Amantadine and rimantadine chemoprophylaxis, which is employed in some countries, provides protection of 80-90% from Influenza A. Recommendations are established for influenza vaccination and a series of situations are quoted where it would be advisable to supplement or replace vaccination with chemoprophylaxis. It is important to attempt to improve the vaccination rates, eg. by means of informative activity, improved planning of the vaccination programmes and public support to vaccination of high-risk groups.
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The study was based on published data from several sources, including a randomized controlled trial of memantine versus placebo and a longitudinal observational study of Alzheimer's disease patients in Sweden. Costs were estimated from the public payer's perspective, including direct costs but excluding costs of informal care, and resource utilization data were taken from the observational study. Cost-effectiveness was quantified as quality-adjusted life-years (QALYs) gained from treatment with the use of previously published utility weights. A Markov simulation model was constructed, incorporating the effect of treatment on cognitive function, physical dependence related to activities of daily living, and institutionalization. Costs and effects for treated and untreated patients were estimated for 5 years (10 cycles). In the base-case analysis, treatment costs were added for 2 years, but the effect on transition probabilities was applied only for the first year of treatment.
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The objective of the study was to demonstrate whether the N-methyl-D-aspartate antagonist, amantadine, can safely ameliorate tardive dyskinesia (TD) without deteriorating the mental state of the patients.
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Patients with moderate-to-severe Alzheimer's disease were randomly assigned to receive placebo or 20 mg of memantine daily for 28 weeks. The primary efficacy variables were the Clinician's Interview-Based Impression of Change Plus Caregiver Input (CIBIC-Plus) and the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory modified for severe dementia (ADCS-ADLsev). The secondary efficacy end points included the Severe Impairment Battery and other measures of cognition, function, and behavior. Treatment differences between base line and the end point were assessed. Missing observations were imputed by using the most recent previous observation (the last observation carried forward). The results were also analyzed with only the observed values included, without replacing the missing values (observed-cases analysis).
Thirty-six (0.27%) patients among the 13,137 who were dispensed amantadine were diagnosed with corneal edema or Fuchs dystrophy within the 2-year study period. The relative risk of corneal edema for a person prescribed amantadine was 1.7 (95% confidence interval: 1.1-2.8). In 12 (0.09%) patients, the corneal diagnoses were recorded within a month of being prescribed amantadine.
The influenza A M2 protein forms proton channels which are blocked by the anti-influenza drug amantadine. Using the technique of neutron diffraction with both deuterium-labeled amantadine and influenza A M2 peptides, this study has directly located the position of interaction between the drug and the transmembrane domain of M2. Amantadine is found 0.5 nm from the center of the bilayer in an area between Val 27 and Ser 31, a location consistent with the formation of a steric block within the ion channel. Similar experiments with amantadine and an amantadine-resistant mutant peptide showed no such interaction.
Increasing evidence supports the hypothesis that escalating levels of excitatory amino acids (EAAs) are responsible for neuronal cell death in a variety of acute neurological conditions including hypoxia/ischemia, trauma, seizures, and hypoglycemia. EAAs may also contribute to several chronic neurodegenerative diseases including Huntington's disease, parkinsonism, and acquired immunodeficiency syndrome dementia. A predominant form of neurotoxicity appears to be mediated by excessive activation of the N-methyl-D-aspartate subtype of glutamate receptor. This laboratory recently reported that memantine, an antiparkinsonian drug, is a potent N-methyl-D-aspartate antagonist capable of preventing the death of central neurons both in vitro and in vivo when given coincident to an EAA insult. In the present study, we found that 12 microM memantine prevented the death of neonatal rat retinal ganglion cells in primary culture when administered up to 4 hours after the initiation of N-methyl-D-aspartate receptor-mediated neurotoxicity.
The effects of Y-8894 on learning and memory were studied using the pole climbing avoidance (PCA) response in intact and experimentally induced amnesic rats. The following results were obtained: A single administration of Y-8894 (2.5 mg/kg, i.p.) to experimentally induced amnesic rats significantly antagonized the decrease in the mean number of PCA responses induced by an electroconvulsive shock (ECS). At a higher dose (10 mg/kg, i.p.), however, this effect was reduced. Repeated administration of Y-8894 (5 mg/kg, i.p.) significantly antagonized the facilitation of the extinction of the PCA response induced by exposure to CO2. Repeated administration of Y-8894 (2.5 mg/kg, i.p.) significantly facilitated the learning of the PCA response in intact rats. At a higher dose (5 mg/kg, i.p.), however, this effect was reduced. A single administration of Y-8894 (5 mg/kg, i.p. and 25 mg/kg, p.o.) significantly delayed the extinction of the PCA response in intact rats. These results suggest that Y-8894 has an ameliorative and facilitative effect on learning and memory in experimentally induced amnesic and intact rats.
The coding region of influenza A virus RNA segment 7 from the 1918 pandemic virus, consisting of the open reading frames of the two matrix genes M1 and M2, has been sequenced. While this segment is highly conserved among influenza virus strains, the 1918 sequence does not match any previously sequenced influenza virus strains. The 1918 sequence matches the consensus over the M1 RNA-binding domains and nuclear localization signal and the highly conserved transmembrane domain of M2. Amino acid changes that correlate with high yield and pathogenicity in animal models were not found in the 1918 strain. Phylogenetic analyses suggest that both genes were mammalian adapted and that the 1918 sequence is very similar to the common ancestor of all subsequent human and classical swine matrix segments. The 1918 sequence matches other mammalian strains at 4 amino acids in the extracellular domain of M2 that differ consistently between avian and mammalian strains, suggesting that the matrix segment may have been circulating in human strains for at least several years before 1918.
To assess the effectiveness and safety of amantadine and rimantadine in preventing, treating and shortening the duration of influenza A in children and the elderly.
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We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of: interventions aimed at reducing relapse rates and disability; interventions to improve symptoms during acute relapse; treatments for fatigue; treatments for spasticity; and multidisciplinary care on disability? We searched: Medline, Embase, The Cochrane Library and other important databases up to November 2006 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Influenza A (H5N1) virus infects a variety of animals, birds and humans. Present ongoing epidemic of this deadly virus in poultry livestock and humans has had major economic and health repercussions. It causes a wide spectrum of clinical features in human beings ranging from mild respiratory tract infection to a fatal pneumonia leading to multi organ system failure. Diagnosis is mainly clinical, aided by lab features like lymphopaenia and non-specific chest X-ray findings. Diagnostic tests are being evolved for rapid and specific diagnosis. Management is mainly symptomatic. Newer and effective antivirals, i.e. amantadine, zanamivir etc are also being tried.