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Biomedical subjects

G L Lenzi

Publications and source records attributed to G L Lenzi.

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

Usefulness of primitive reflexes in demented and non-demented cerebrovascular patients in daily clinical practice.

The aim of this study was to investigate the usefulness of primitive reflexes (PRs) as additional alert signs in a routine clinical setting of cognitive decline in an elderly population of chronic ischemic cerebrovascular patients. We considered the occurrence of grasp, palmomental, glabellar and snout reflexes in 75 demented (VaD) and 75 non-demented (VaND) patients, and in 75 healthy elderly controls. We never elicited more than two PRs in controls. The occurrence of three or four PRs provided the strongest correlation with dementia (p < 0.0001), with 93% specificity irrespective of low sensitivity. In conclusion, the occurrence of more than two PRs might serve as an additional warning sign of possible mild cognitive impairment in chronic ischemic cerebrovascular patients.

Aged↗
PubMed2000

Identification of lacunar infarcts before thrombolysis in the ECASS I study.

BACKGROUND: The identification of lacunar infarcts before thrombolysis would make it possible either to exclude them from treatment or to show that they also may benefit from it. OBJECTIVE: To determine whether clinical presentation or early CT findings of patients enrolled in the first European Cooperative Acute Stroke Study (ECASS I) trial would identify lacunar infarcts before treatment. METHODS: Predictive values, sensitivity, specificity, and accuracy of clinical presentation as pure motor hemiparesis (PMH) or sensorimotor stroke (SMS) syndromes and of baseline CT findings in predicting lacunar infarcts were calculated in the ECASS I patients. RESULTS: Of 514 patients, 44 placebo (17%) and 44 recombinant tissue plasminogen activator (rt-PA) (18%) patients had PMH/SMS involving at least two of three areas. Thirty-one placebo (12%) and 32 rt-PA (13%) patients had PMH/SMS involving three areas. The 7-day CT was compatible with a lacunar infarct in 32 placebo (12%) and 44 rt-PA (18%) patients. PMH/SMS involving at least two areas had a positive predictive value of 30% both in placebo and rt-PA patients, whereas positive predictive values of the involvement of three areas were 23% and 31%. Those of absence of early CT signs were 21% and 30%, and those of leukoaraiosis or previous lacunar infarcts were 21% and 23%. Positive predictive values of PMH/SMS involving at least two areas combined with absence of early CT signs were 36% in placebo and 33% in t-PA patients, and those of PMH/SMS plus leukoaraiosis or previous lacunes were 28% and 7%, respectively. CONCLUSIONS: In the ECASS I trial, lacunar infarcts were not recognizable on clinical grounds, and early CT findings, alone or in combination with the clinical picture, added poorly to the differential diagnosis.

Cerebral Infarction↗
PubMed2000

Bromocriptine and speech therapy in non-fluent chronic aphasia after stroke.

The objectives of this study were to investigate the efficacy of bromocriptine (BR) combined with speech therapy (ST) to improve a late recovery in non-fluent aphasic stroke patients. We performed a double-blind study with high dosage of BR, prescribed according to a dose-escalating protocol, comprehensive of clinical data, relatives' impression, and language evaluations. The study was divided into the following phases: t-0, inclusion; t-30, language re-test to evaluate the stability of aphasia; t-90, placebo (PL) and ST; t-150, BR and ST; t-210, BR; t-270, wash-out. With respect to the baseline assessment, a significant improvement was observed in the following tests: dictation (F, 4.8; p < .004), reading-comprehension (F, 8.1; p < .0003), repetition (F, 3.8; p < .01) and verbal latency (F, 4.9; p < .01). High dosage of BR promoted a late recovery in stable chronic non-fluent aphasia and this improvement was enhanced by combination with ST.

Aged↗
PubMed2000

Migraine patients show an increased density of dopamine D3 and D4 receptors on lymphocytes.

Recent studies have revealed peculiar functional and genetic features of dopamine receptors in migraine. As peripheral blood lymphocytes (PBL) may represent a tool for peripheral detection of neuroreceptors, we compared the expression of dopamine D3 (DRD3) and D4 (DRD4) receptors on PBL in migraine patients and in healthy controls using radioligand binding assay techniques in the presence of antidopamine D2-like receptor antibodies. The dopamine D2-like receptor agonist [3H]7-OH-DPAT was used as a radioligand. An increased density of both DRD3 (P=0.0006) and DRD4 (P=0.002) on PBL was observed in migraineurs compared with controls. This up-regulation might reflect central and/or peripheral dopamine receptor hypersensitivity due to hypofunction of the dopaminergic system. These findings support the view that dopamine D2-like receptors are involved in the determination of the so-called migraine trait, which may help to elucidate several clinical features of the disease.

Adult↗
PubMed2000

Dopamine and migraine: does Parkinson's disease modify migraine course?

As brainstem mechanisms and dopaminergic neurotransmission are involved in migraine pathophysiology, we decided to investigate the course of migraine in Parkinson's disease (PD), the paradigm of brainstem dopaminergic disease. We screened 237 consecutive PD out-patients by direct interview to assess the prevalence of lifetime and current migraine. Moreover, we compared the course of migraine in PD patients with that of otherwise healthy age- (+/- 3 years) and sex-paired migraine controls in a cross-sectional study. PD patients showed a lifetime migraine prevalence of 27.8% and a current migraine prevalence of 13.1%. A positive family history of migraine was less frequent in PD patients than in controls. The frequency of current migraine was significantly lower in PD patients than in controls (47.0% vs. 68.2%; odds ratio = 0.41, 95% confidence interval = 0.19-0.89). Approximately two-thirds of PD patients reported an improvement in or remission of migraine after PD onset. Effects of menopause on migraine course were similar in patients and controls. These findings suggest that PD might somehow shorten the clinical course of migraine. Possible explanations include a prolonged prophylactic effect by chronic dopaminergic therapy or a positive effect of PD pathophysiology, namely nigral degeneration, on migraine mechanisms.

Aged↗
PubMed1999

Increased expression of dopamine receptors on lymphocytes in Parkinson's disease.

Dopamine D1-like and D2-like receptors on peripheral blood lymphocytes (PBL) were assayed in 50 de novo patients with idiopathic Parkinson's disease (PD), in 36 neurologic control subjects (multiple-system atrophy, n = 16; essential tremor, n = 10; other neurodegenerative diseases, n = 10), and in 26 healthy control subjects by radioligand binding assay techniques using [3H]SCH 23390 and [3H]7OH-DPAT as ligands. Patients with PD revealed a higher density (Bmax) of dopamine D1-like (p <0.001) and D2-like (p <0.00001) receptors on PBL than either neurologic or healthy control subjects, whereas no differences in Bmax were observed among patients affected by other neurologic diseases and healthy control subjects. The affinity (Kd) of both radioligands was similar in the groups investigated. The pharmacologic profile of [3H]SCH 23390 and [3H]7OH-DPAT binding was consistent with the labeling of dopamine D5 and D3 receptor subtypes, respectively. Twenty-five of the 50 patients with PD were retested after 3 months of therapy with levodopa or bromocriptine. Both treatments reduced the density of D1-like (p <0.001) and D2-like (p <0.001) receptors on PBL to values comparable to those of control subjects. The increased density of D1-like and D2-like receptors on PBL in de novo PD patients may represent an upregulation mechanism resulting from the diffuse impairment of the dopaminergic system in PD.

Aged↗
PubMed1999

Cortical control of optokinetic nystagmus in humans: a positron emission tomography study.

Positron emission tomography (PET) was used to address the issue of physiological changes in the cerebral cortex associated to optokinetic nystagmus (OKN) in humans. We studied regional cerebral blood flow in eight volunteers during reflexive induction of OKN by a pattern of dots moving unidirectionally (toward the left side). We used two control conditions, with subjects passively viewing either stationary or incoherently moving dots. This paradigm was designed in order to differentiate the OKN-related activations from blood flow changes related to visual motion. When compared with the stationary condition, OKN activated a set of occipital areas known to be sensitive to visual motion. Bilateral activation was found in the striate cortex (V1) and the parieto-occipital fissure, while area V5, the intraparietal sulcus, and the pulvinar were activated only in the left hemisphere. When compared with incoherent motion, OKN activated the V1 and the parieto-occipital fissure bilaterally and the right lingual gyrus, while a signal decrease was observed in the V5 region in both hemispheres. No significant signal changes were found in areas implicated in saccades or in processing vestibular information. These results indicate that processing of OKN-related information is associated with neural activity in a specific set of visual motion areas and suggest that this network can be asymmetrically activated by a strictly unidirectional stimulation. Results are also discussed in terms of the specific kinds of OKN-related information processing subserved by each area in this network.

Adult↗
PubMed1999

Emission tomography contribution to clinical neurology.

The role of functional neuroimaging techniques in furthering the understanding of pathophysiological mechanisms of neurological diseases and in the assessment of neurological patients is increasingly important. Here, we review data mainly from emission tomography techniques, namely positron emission tomography (PET) and single photon emission computerized tomography (SPECT), that have helped elucidate the pathophysiology of a number of neurological diseases and have suggested strategies in the treatment of neurological patients. We also suggest possible future developments of functional neuroimaging applied to clinical populations and briefly touch on the emerging role of functional magnetic resonance imaging (fMRI) in clinical neurology and neurosurgery.

Brain↗
PubMed1999

Linguistic impairment after right cerebellar stroke: a case report.

Increasing evidence suggests the involvement of the cerebellum in non-motor functions. We describe a patient who presented speech deficits after a right cerebellar infarction without other cognitive impairments. 99mTc-HMPAO single-photon emission computed tomography showed a marked hypoperfusion in the right cerebellar hemisphere, but did not show crossed cerebellar- cerebral diaschisis. The absence of neuroradiological evidence of structural supratentorial lesions supports the cerebellar role in modulating not only the motor system, but also higher order functions.

Cerebellum↗
PubMed1998

Differential level of platelet amyloid beta precursor protein isoforms: an early marker for Alzheimer disease.

OBJECTIVE: To determine whether a differential level of platelet amyloid beta precursor protein (APP) isoforms is specifically related to Alzheimer disease (AD) and whether it shows a correlation with the progression of clinical symptoms. DESIGN: After subjects were grouped according to diagnosis and severity of dementia, APP isoform levels in platelets were compared. SETTING: University medical centers. PATIENTS: Thirty-two patients who fulfilled diagnostic criteria for probable AD, 25 age-matched control subjects, and 16 patients with non-AD dementia. MAIN OUTCOME MEASURE: The levels of APP isoforms were evaluated by means of Western blot analysis and immunostaining of whole platelets. Messenger RNAs for APP transcripts were also evaluated by means of reverse transcriptase polymerase chain reaction. RESULTS: The ratio between the intensity of the 130-kd and 106- to 110-kd APP isoforms was significantly lower in the AD group (0.31 +/- 0.15, mean +/- SD) compared with both controls (0.84 +/- 0.2) and non-AD subjects (0.97 +/- 0.4). The ratio of platelet APP isoforms in patients with AD grouped by Clinical Diagnostic Rating score significantly correlated with the severity of the disease (Pearson correlation coefficient, followed by Bonferroni correction, P = .01). Reverse transcriptase polymerase chain reaction experiments showed that APP transcripts in all experimental groups were equally expressed. CONCLUSIONS: The pattern of platelet APP isoforms is specifically altered in patients with AD. In addition, the alteration of platelet APP isoforms shows a positive correlation with the progression of clinical symptoms, supporting the possibility to consider this peripheral parameter as a marker of progression of the disease. These alterations are not related to abnormalities of APP isoforms messenger RNAs in platelets.

Adult↗
PubMed1997

Merging of oculomotor and somatomotor space coding in the human right precentral gyrus.

Using PET and H215O, we investigated the cortical areas that merge two different ways of coding space in the cerebral cortex, those concerned with the oculomotor and the somatomotor space. Normal subjects performed a visuomotor task that required the spatial coding of visual stimuli in oculomotor space and of motor responses in somatomotor space. We manipulated the mapping of oculomotor and somatomotor space by instructing subjects to respond in half of the PET scans with uncrossed hands, i.e. each hand was in the homonymous hemispace (standard oculomotor-somatomotor mapping), and in the other half with crossed hands, i.e. with the left hand in the right hemispace and the right hand in the left hemispace (nonstandard oculomotor-somatomotor mapping). Reaction times were slower for crossed hands than uncrossed hands. Crossed hands produced increases in blood flow in the precentral and postcentral gyri of the right hemisphere. Increases in blood flow in the precentral gyrus were correlated with increases in reaction time comparing the crossed-hand task with the uncrossed one, whereas the increases in blood flow in the postcentral gyrus were not. These findings suggest that the right precentral gyrus merges oculomotor and somatomotor space coding in the human brain.

Adult↗
PubMed1997

Dopamine hypersensitivity in migraine: role of the apomorphine test.

We investigated the effects of apomorphine administration at two different doses (2-10 micrograms/kg, s.c.) in 35 migraineurs in headache-free period and in 20 age-matched healthy control subjects, with and without pretreatment with domperidone. Neither patients or controls complained of headache at either dose, whereas at the dose of 10 micrograms/kg migraineurs showed a statistically significant higher incidence of dopaminergic symptoms (nausea, vomiting, drowsiness, yawning, dizziness, sweating) than controls. Furthermore, symptoms due to postsynaptic dopamine receptors activation (i.e., nausea and vomiting) only appeared in migraineurs. No symptom, however, resembled those characterizing a spontaneous migraine attack. In conclusion, migraineurs show a lower threshold for dopamine receptor activation than normal subjects.

Adult↗
PubMed1996

Involvement of the limbic system in multiple sclerosis patients with depressive disorders.

This study investigates the relationship between depression and both anatomic and cerebral blood flow abnormalities in multiple sclerosis (MS) patients. Ten nondepressed MS patients were compared with 10 depressed MS patients matched for age, sex, and functional disability. Both groups were evaluated by means of neuropsychological tests, magnetic resonance imaging, and single-photon emission tomography imaging. There was no difference between the two groups with regard to the global cognitive score. Magnetic resonance imaging data showed no significant differences in the number, side, location, and area of the demyelinating lesions between the two groups; however, regional cerebral blood flow asymmetries in the limbic cortex did distinguish the two groups. Analysis of variance showed a significant effect of depression on the perfusion asymmetries in the limbic cortex. Finally, perfusion asymmetries in limbic cortex significantly correlated with depression test scores. Our findings suggest that depression in MS patients could be induced by a disconnection between subcortical and cortical areas involved in the function of the limbic system.

Adult↗
PubMed1996

Increased density of dopamine D5 receptor in peripheral blood lymphocytes of migraineurs: a marker for migraine?

The expression of dopamine D5 receptor was investigated in peripheral blood lymphocytes of 11 migraine patients and of ten healthy control subjects using a radioligand binding technique with [3H]SCH 23390 as a ligand. [3H]SCH 23390 is a benzazepine derivative with potent antagonist properties at the dopamine D1-like receptors. [3H]SCH 23390 was specifically bound to peripheral blood lymphocytes of migraineurs and control subjects in a manner consistent with the labelling of a dopamine D5 receptor. In migraineurs a statistically significant higher density of lymphocyte dopamine D5 receptor compared with controls was noticeable, whereas the affinity of the radioligand was unchanged. The increased density of dopamine D5 receptor in peripheral blood lymphocytes may reflect the dopaminergic hypersensitivity displayed by migraineurs and may represent a relatively simple and reliable peripheral marker of altered dopaminergic function.

Adult↗
PubMed1996

Functional basis of memory impairment in multiple sclerosis: a[18F]FDG PET study.

Structural neuroimaging has been used to correlate lesional patterns with the cognitive profile of patients with multiple sclerosis (MS), especially for "frontal" dysfunction. However, a clear-cut anatomical explanation has yet to be found for the long-term memory deficit which is a hallmark of MS cognitive impairment. We have used PET to measure regional cerebral glucose metabolism (rCMRglc) in a group of 15 MS patients with involvement of verbal and/or spatial long-term memory. These patients were compared with 10 normal controls and 13 MS patients unimpaired on all neuropsychological tests. Relative to the controls, MS patients with memory deficits showed a significant bilateral reduction of rCMRglc in the hippocampus, cingulate gyrus, thalamus, associative occipital cortex, and cerebellum. Direct comparisons between patients with memory deficits and the group of unimpaired MS patients showed a metabolic reduction in the left thalamus and in both hippocampi. Seven of the memory-impaired patients also had neuropsychological signs of frontal dysfunction. These patients were compared with patients who had isolated memory deficit. Here we observed a further metabolic reduction in a number of brain regions including bilateral prefrontal cortex, inferior parietal cortex, and basal ganglia. Our findings indicate that hypometabolism of thalamic and deep cortical gray structures of the temporal lobe is associated with episodic memory dysfunction in MS. On the other hand, pathological performance on tests designed to assess frontal functions was associated with widespread reduction of glucose metabolism.

Adult↗