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Biomedical subjects

L Murri

Publications and source records attributed to L Murri.

At least 37 records · Page 2Linked to original sources
PubMed2005

From mild cognitive impairment to dementia: a prevalence study in a district of Tuscany, Italy.

OBJECTIVE: A door-to-door two-phase study was designed in order to estimate the prevalence of cognitive deficit amongst the residents of a district in Tuscany (central Italy). Identification of cases with mild cognitive impairment (MCI) was given high priority, because this condition has been suggested as a term for the boundary area between normal aging and dementia. METHODS: Of the 1600 subjects who completed the screening phase, 354 scored under the cut-off point of the Mini Mental State Examination and Clinical Dementia Rating and were investigated by means of a standardized diagnostic protocol. RESULTS: The prevalence of MCI and age-related cognitive decline was 4.9 and 9.3%, respectively; low levels of education significantly increased the risk of these conditions. The prevalence of dementia over age 65 was 6.2%, with a significant risk association with age. In our population, Alzheimer's disease was the most frequent type of dementia (prevalence rate 4.2%) and increased risk depending on age, sex and education has been found. CONCLUSIONS: Our findings are somewhat similar to previous studies. Further epidemiological and longitudinal studies are warranted to identify which diagnostic category is more predictive for dementia.

Age Factors↗
PubMed2004

Presynaptic nigro-striatal function in a group of Alzheimer's disease patients with parkinsonism: evidence from a dopamine transporter imaging study.

The occurrence of parkinsonism in Alzheimer's disease (AD) is quite common, however the molecular and neurochemical changes underlying such extrapyramidal features in AD have been not fully understood. Post-mortem as well as in vivo imaging study have produced conflicting results as regards the existence of dopaminergic changes in AD. Aim of the present study was to investigate in vivo the nigro-striatal dopaminergic function in a group of AD patients with parkinsonism. Thirteen patients with AD and extrapyramidal features not related to past neuroleptic use (AD-P) underwent SPECT with 123I-FP-CIT, a ligand of dopamine transporter, and the data were compared with those obtained in 15 patients with Diffuse Lewy Body Dementia (DLBD), 20 patients with Parkinson's disease (PD), and 8 healthy elderly controls. The analysis of the data was performed by regions-of-interest approach and calculations of the striatal-to-non specific (occipital lobes) radioactivity ratios were made. The 123I-FP-CIT striatal uptake in patients with AD-P was similar to that obtained in the control population. Both the DLBD and PD groups showed significantly lower 123I-FP-CIT uptake in all striatal areas with respect to AD-P and control groups (p < 0.005). The lack of dopamine transporter changes in our series of AD-P patients can indicate that dopaminergic presynaptic function is preserved in this population and that different dopaminergic changes such as postsynaptic ones, or different neurotransmitter alterations might underlie the extrapyramidal features in AD.

Aged↗
PubMed2004

A novel mitochondrial tRNAPhe mutation causes MERRF syndrome.

A woman with typical features of myoclonic epilepsy with ragged red fibers (MERRF) had a novel heteroplasmic mutation (G611A) in the mitochondrial DNA tRNA phenylalanine gene. The mutation was heteroplasmic (91%) in muscle but undetectable in accessible tissues from the patient and her maternal relatives. Single-fiber PCR analysis showed that the proportion of mutant genomes was higher in cytochrome c oxidase (COX)-negative ragged red fibers (RRFs) than in COX-positive non-RRFs. This report shows that typical MERRF syndrome is not always associated with tRNA lysine mutations.

Adolescent↗
PubMed2004

Rapid eye movement activity before spontaneous awakening in elderly subjects.

Previous research in young subjects found that rapid eye movement (REM) density is higher in those REM phases which are followed by an awakening (REM-W) than in those preceding NREM (REM-N), suggesting a 'gating role' of REM sleep toward the awakening. It is not yet known whether this evidence is maintained in elderly subjects, who display, relative to young subjects, more awakenings, different sleep states from which the awakenings come (NREM in a high proportion of cases) and a general impairment of rapid eye movement activity (REMA). To investigate this issue, we have compared in three different age groups (young, old and 'old old' subjects) the features of REMA, including REM density and the amount and duration of REM bursts, between REM-W and REM-N. Whereas in the young REM density is higher in REM-W than in REM-N, this difference is already reduced in the old group and fully cancelled in the old old subjects. The evidence that old individuals spontaneously wake up despite the absence of an increase of REMA could imply that in the aged awakening is not preceded by an increase of the arousal level (expressed in REM sleep by the REMA). The similar duration of REM bursts for REM-W and REM-N in both groups of old subjects suggests that with age a marked impairment occurs in the organizational aspects of REMs, independently from the following state.

Adult↗
PubMed2004

A non-syndromic hearing loss caused by very low levels of the mtDNA A3243G mutation.

We described a patient with progressive non-syndromic hearing loss (NSHL) harboring the A3243G mutation in the mitochondrial DNA (mtDNA). Muscle biopsy showed scattered ragged-red, cytochrome c oxidase negative fibers, whereas the biochemical analysis of the mitochondrial respiratory chain complexes was normal. Restriction fragment length polymorphism (RFLP) analysis showed A3243G mtDNA transition, present at very low in patient's muscle (3%) and in urinary sediments (1%), and not detectable in blood and buccal mucosa. The patient was submitted to a bilateral cochlear implantation with post-operative excellent hearing and communicative outcomes. Our findings indicate that A3243G mutation may be responsible both for SHL and NSHL, may be depending on the levels of mutated mtDNA. Patients with hearing loss due to mtDNA mutations should be considered as good candidates for cochlear implantation.

Aged↗
PubMed2003

Causative and susceptibility genes for Alzheimer's disease: a review.

Alzheimer's disease (AD) is the most common type of dementia in the elderly population. Three genes have been identified as responsible for the rare early-onset familial form of the disease: the amyloid precursor protein (APP) gene, the presenilin 1 (PSEN1) gene and the presenilin 2 (PSEN2) gene. Mutations in these genes, however, account for less than 5% of the total number of AD cases. The remaining 95% of AD patients are mostly sporadic late-onset cases, with a complex aetiology due to interactions between environmental conditions and genetic features of the individual. In this paper, we review the most important genes supposed to be involved in the pathogenesis of AD, known as susceptibility genes, in an attempt to provide a comprehensive picture of what is known about the genetic mechanisms underlying the onset and progression of AD. Hypotheses about the role of each gene in the pathogenic pathway are discussed, taking into account the functions and molecular features, if known, of the coded protein. A major susceptibility gene, the apolipoprotein E (APOE) gene, found to be associated with sporadic late-onset AD cases and the only one, whose role in AD has been confirmed in numerous studies, will be included in a specific chapter. As the results reported by association studies are conflicting, we conclude that a better understanding of the complex aetiology that underlies AD may be achieved likely through a multidisciplinary approach that combines clinical and neurophysiological characterization of AD subtypes and in vivo functional brain imaging studies with molecular investigations of genetic components.

Alzheimer Disease↗
PubMed2003

IV amantadine improves chorea in Huntington's disease: an acute randomized, controlled study.

The acute antidyskinetic effects of IV amantadine in HD were evaluated. A 2-hour IV infusion of amantadine or placebo was administered to nine patients with HD on two different days in a double-blind, randomized crossover fashion. All patients subsequently received oral amantadine unblinded for a 1-year period. A reduction of dyskinesia scores was reported during both IV and oral amantadine treatment (p < 0.05). No significant changes were observed in neuropsychological tests or psychiatric rating scales.

Administration, Oral↗
PubMed2003

Dopaminergic degeneration and perfusional impairment in Lewy body dementia and Alzheimer's disease.

The clinical differentiation of Lewy body dementia (LBD) from Alzheimer's disease (AD) may be difficult. The aim of the present study was to assess the dopamine transporter function and the perfusional pattern in LBD and AD in vivo. Twenty patients with probable LBD and 24 with probable AD underwent on 2 separate days a brain perfusional SPECT with 99mTc-ECD and a SPECT with (123)I-FP-CIT, a ligand of dopamine transporter. In LBD a significantly ( p<0.0005) lower ratio of specific (bilateral caudate nucleus, putamen) to non-specific (occipital cortex) (123)I-FP-CIT binding than in AD was reported. Perfusional data (SPM analysis) showed a significant ( p<0.001) decrease of temporo-parietal blood flow in AD versus LBD, whereas in LBD a significant ( p<0.001) occipital hypoperfusion with respect to AD was reported. Our findings confirm that dopaminergic nigrostriatal function is impaired in LBD. The selective occipital hypoperfusion in LBD needs to be further investigated.

Aged↗
PubMed2003

Autosomal dominant external ophthalmoplegia and bipolar affective disorder associated with a mutation in the ANT1 gene.

The authors report on a family with dominantly inherited progressive external ophthalmoplegia and a diagnostic and statistical manual (fourth revised edition) diagnosis of bipolar psychiatric disorder in several members. Skeletal muscle biopsy from the proposita showed decreased cytochrome c oxidase staining, several ragged-red fibers, and multiple mtDNA deletions. The authors identified a missense mutation (leucine 98-->proline) in the adenine nucleotide translocator 1 gene. The presence of bipolar affective disorder expands the phenotype of adenine nucleotide translocator 1 allelic variants.

Adenine Nucleotide Translocator 1↗
PubMed2003

The prognostic value of evoked responses from primary somatosensory and auditory cortex in comatose patients.

OBJECTIVE: To evaluate somatosensory and auditory primary cortices using somatosensory evoked potentials (SEPs) and middle latency auditory evoked potentials (MLAEPs) in the prognosis of return to consciousness in comatose patients. METHODS: SEPs and MLAEPs were recorded in 131 severe comatose patients. Latencies and amplitudes were measured. Coma had been caused by transient cardiac arrest (n=49), traumatic brain injury (n=22), stroke (n=45), complications of neurosurgery (n=12) and encephalitis (n=3). One month after the onset of coma patients were classified as awake, still comatose or dead. Three months after (M3), they were classified into one of the 5 categories of the Glasgow outcome scale (GOS). RESULTS: At M3, 41.2% were dead, 47.3% were conscious (GOS 3-5) and 11.5% had not recovered consciousness. None of the patients in whom somatosensory N20 and auditory Pa were absent did return to consciousness and in the post-anoxic group, reduced cortical amplitude too was always associated with bad outcome. Conversely, N20 and Pa were present, respectively, in 33/69 and 34/69 patients who did not recover. CONCLUSIONS: The prognostic value of SEPs and MLAEPs in comatose patients depends on the cause of coma. Measurement of response amplitudes is informative. Abolition of cortical SEPs and/or cortical MLAEPs precludes post-anoxic comatose patients from returning to consciousness (100% specificity). In any case, the presence of short latency cortical somatosensory or auditory components is not a guarantee for return to consciousness. Late components should then be recorded.

Adolescent↗
PubMed2003

Serotoninergic polymorphisms (5-HTTLPR and 5-HT2A): association studies with psychosis in Alzheimer disease.

Patients with Alzheimer disease (AD) often exhibit psychotic symptoms associated with cognitive impairment. A few association studies have been carried out to determine if the serotonin transporter and receptor genes are potential risk factors for AD and/or associated psychopathology. The aim of this study was to investigate the association of a serotonin transporter gene-linked polymorphic region (5-HTTLPR) and the 5-HT2A receptor T102C polymorphism with the risk of developing dementia and/or psychotic symptoms in a group of sporadic AD patients from Italy. No significant differences in the distribution of allele and genotype frequencies of 5-HTTLPR and 5-HT2A T102C were found between patient and control groups. However, a significant association between the C102/C102 5-HT2A genotype and psychotic symptoms (p < 0.001) was observed. Our data strongly confirm results from previous studies suggesting that the C102 allele of the 5-HT2A receptor is associated with the occurrence of psychotic symptoms in AD. On the contrary, the serotonin transporter does not appear to be a major susceptibility factor in the pathophysiology of the disease.

Aged↗
PubMed2002

Contrast-enhanced three-dimensional MR angiography of neck vessels: does dephasing effect alter diagnostic accuracy?

The aim of this study was to evaluate diagnostic accuracy of contrast-enhanced MRA (CEMRA) compared with digital subtraction angiography (DSA) in studying neck vessels of 48 patients. In three groups of patients, we used three MRA protocols differing for voxel size to assess if intravoxel dephasing effects could modify accuracy of CEMRA. Accuracy and correlation with DSA results were calculated in all patients and separately in the three groups. A qualitative analysis of the likeness between morphology of the stenosis in CEMRA and DSA images was also assessed. In all patients accuracy and agreement with DSA were 96% and k=0.85 in subclavian arteries, 96% and k=0.84 in vertebral artery, 97% and k=0.88 in common carotid arteries, and 94% and k=0.86 in internal carotid arteries. In the three groups accuracy and agreement with DSA did not show any significant difference. Qualitative analysis of CEMRA and DSA images revealed a better agreement in depicting the morphology of stenosis using a smaller voxel size. The CEMRA represents a powerful tool for the non-invasive evaluation of neck vessels. Overestimation trend of CEMRA is confirmed and the reduction of voxel size, decreasing the dephasing intravoxel effect, allows to have a better overlapping of stenosis morphology on CEMRA compared with DSA, but it does not yield diagnostic gain in the stenosis grading.

Aged↗
PubMed2002

Contribution of cerebellum and brainstem in the control of eye movement: evidence from a functional study in a clinical model.

The idiopathic cerebellar ataxias (IDCA) comprise a wide spectrum of neurodegenerative diseases with heterogeneous neuropathology, characterized by the negativity of search for any known genetic mutation. On the basis of both their clinical presentation and their magnetic resonance imaging pattern, patients with IDCA can be subdivided into patients with a purely cerebellar syndrome and atrophy of the cerebellum (IDCA-C) and patients with additional noncerebellar symptoms and atrophy of both cerebellum and brainstem (IDCA-P). The aim of the present study was to evaluate the disaggregated contribution of brainstem and cerebellum in the control of eye movements, by means of an extensive battery of quantitative tests covering most oculomotor subfunctions related to lesions of the cerebellum and the brainstem. The smooth-pursuit movement analysis showed a decrease in gain and magnitude in both subgroups of IDCA with respect to normal controls, without any significant differences in the prevalence pattern between the two subgroups; the mean values of these parameters, however, were significantly lower in IDCA-P than in IDCA-C subjects in both gain (P < 0.01) and magnitude (P < 0.001). No statistically significant difference was observed between the two subgroups in the analysis of saccadic movements or in the other parameters investigated. The distinction between IDCA-P and IDCA-C subgroups has clinical implications, as a poorer prognosis is related to brainstem involvement, which may occur late in the course of the disease. Thus, the possibility to detect the brainstem involvement, also in association with cerebellar impairment, by a relatively simple eye-movement analysis, potentially useful mainly in follow-up investigations, needs to be evaluated further.

Adult↗
PubMed2002

Dissection and atherosclerosis of carotid arteries in the young: role of the apolipoprotein E polymorphism.

Twenty-seven young (<50 years old) patients with spontaneous carotid artery dissection in 11 cases and carotid atherosclerosis in 16 cases were evaluated to determine the apolipoprotein E polymorphism. At the DNA analysis the epsilon3/epsilon3 genotype was observed in all patients with dissection, in 13 of 16 (81.2%) patients with atherosclerosis and in 27 of 30 (90%) controls. Three of 16 (18.8%) patients with atherosclerosis and 3 of 30 (10%) controls presented with the epsilon4/epsilon3 genotype, and this difference was not statistically significant. Moreover, observation of the epsilon4/epsilon3 genotype was not significantly higher in patients with atherosclerosis compared with those with dissection. No homozygote epsilon4/epsilon4, epsilon2/epsilon2 or heterozygote epsilon2 genotype was observed. No correlation was found between the presence of the epsilon4/epsilon3 genotype and vascular risk factors. Therefore, the epsilon4 allele seems to be involved in carotid premature atherosclerosis development whereas it may appear to be protective for artery dissection occurrence. A larger sample size is needed to support this suggestion.

Adult↗
PubMed2002

Lormetazepam effects on daytime vigilance, psychomotor performance and simulated driving in young adult healthy volunteers.

OBJECTIVE: To assess the residual effects of lormetazepam on daytime vigilance, psychomotor performance and simulated driving in adult healthy volunteers. MATERIAL: Twelve subjects (7 women, 5 men), aged 27 - 38 years (mean 31). METHOD: Subjects received lormetazepam 1 mg tablet and placebo for 3 days at nighttime in a randomized, double-blind, crossover design, with a 1-week interval between medications. On the morning following the last drug administration, the subjects completed a 15-min battery of neuropsychological tests aimed at assessing memory and attention, performed simple and choice visual reaction times, and self-rated their own level of sleepiness using the Epworth sleepiness scale. Afterwards, an interactive, computer-based driving simulator (STISIM) was used to assess the effect of the study drugs on driving ability, followed by the multiple sleep latency test (MSLT). RESULTS: The findings showed that participants had similar performance when treated with lormetazepam and placebo. Indeed, as compared with baseline, neuropsychological tests, visual reaction times, sleep latency using the MSLT and driving ability showed no deterioration following either placebo or active medication. CONCLUSIONS: The data suggest that 3-day use of lormetazepam 1 mg/day neither influences daytime vigilance nor impairs psychomotor task performance and simulated driving. Results confirm previous evidence that the intermediate-acting hypnotic benzodiazepine lormetazepam is devoid of residual effects in respect to psychomotor ability. However, caution should be exercised in the interpretation of the results due to the limited sensitivity of the study.

Adult↗
PubMed2001

Impaired oxidative metabolism in exercising muscle from ALS patients.

The pathogenic mechanism of selective loss of motor neurones in amyotrophic lateral sclerosis (ALS) is still poorly understood. Recently, research evidence has suggested that mitochondrial dysfunction occurs in central nervous system as well as in peripheral tissues from ALS patients. The aim of our study was to indirectly investigate in vivo oxidative metabolism of exercising muscle in a case history of patients affected by ALS. To this purpose 11 patients, 8 male and 3 female, mean age+/-SD: 52.4+/-11.1 years, performed a bicycle incremental test for the assessment of lactate production. At rest, there was increased lactate concentration in patients: 2.77+/-0.79 vs. 1.48+/-0.49 mmol/l in normal controls (normal range: 0.67-2.47 mmol/l). Analysis of lactate curve during exercise showed a lactate production increase compared to controls. Furthermore, anaerobic lactate threshold was detected at 40-50% of the predicted normal power output, anticipated with respect to both normal subjects and non-ALS chronically denervated controls with comparable motor impairment (60-70%), suggesting that mitochondrial dysfunction can occur in exercising skeletal muscle from ALS patients.

Adult↗
PubMed2001

Effects of sleep on spinal nociceptive reflexes in humans.

Controversy continues to surround the monosynaptic and polysynaptic spinal reflexes during the different stages of sleep. In animal studies both of these reflexes were found to be depressed during desynchronized sleep. In humans, the H reflex was unchanged whereas the second component of the nociceptive flexion reflex was increased. However, abolition of the H reflex and F waves during REM sleep has also been reported. The aim of this investigation was to examine the effects of different sleep stages on the polysynaptic nociceptive flexion reflex. Six healthy volunteers were studied. The RIII reflex was studied according to Willer's method (1977) during the different stages of NREM and REM sleep. The RIII reflex threshold was found to increase during stage 2 of NREM sleep. It remained higher during stages 3 and 4. During REM sleep a further increase in the reflex threshold was observed. The reflex latency was prolonged during stage 4 of NREM sleep. There was evidence of further latency prolongation during REM sleep. It was also during REM sleep that the maximum increase in the amplitude and duration of the reflex were recorded.

Adult↗