Search PubMed⌕ Search

Biomedical subjects

G Sandrini

Publications and source records attributed to G Sandrini.

At least 19 recordsLinked to original sources
PubMed1992

The trigemino-pupillary reflex: a model of sensory-vegetative integration.

Trigeminal stimulation can induce pupillary changes. In vivo and in vitro studies have demonstrated that electrical impulses applied at the trigeminal level can provoke a miotic response, whose nature has been ascribed to the anti-dromic release of neuropeptides (substance P in particular). In order to better define the pupil response to trigeminal stimulation, we investigated the human pupil response to quantified (painless and painful) corneal stimuli by means of a combined (neurophysiological and pharmacological) technique. The response to corneal stimulation was bilateral, direct and consensual. It had a biphasic progression with an initial mydriasis (which directly correlated with the stimulus intensity), followed by a miotic phase. The mydriatic phase disappeared after thymoxamine application, while homatropine pre-treatment prevented occurrence of the miotic phase. The data obtained indicate that the pupillary response to corneal stimulation (trigemino-pupillary reflex) is a multisynaptic reflex with an afferent branch involving the trigeminal system, and an afferent branch involving both the sympathetic and the parasympathetic system. Other pathways, such as the SP-mediated release of acetylcholine, cannot be excluded. Thus the reflex appears to be a potentially useful tool for investigating pain/vegetative interactions in various clinical conditions. In turn, the description of its changes in pathologies characterized by a sympathetic/parasympathetic deficit or by a SP-ergic imbalance will allow us to better describe its inner mechanisms.

Adult↗
PubMed1992

Multimodal evoked potentials in myotonic dystrophy (MyD).

By means of multimodal evoked potentials (EPs), we evaluated the central nervous system (CNS) involvement in 25 subjects suffering from myotonic dystrophy: brainstem auditory evoked potentials (BAEPs), middle-latency auditory evoked potentials (MLAEPs) and somatosensory evoked potentials (SEPs) from the upper limb were performed on all subjects, whereas only the 19 patients, whose clinical ocular abnormalities were slight, underwent pattern-electretinograms (PERGs) and pattern visual-evoked potentials (VEPs) in order to identify the site of lesion among visual pathways (retinal and/or retroretinal). PERGs were abnormal in 8/19 subjects, VEPs in 8/19 subjects (the two techniques were simultaneously abnormal in 8 eyes), BAEPs in 7/25 subjects, MLAEPs in 4/25 subjects (in one subject both BAEps and MLAEPs were abnormal) and SEPs were abnormal in 1/25 subjects. 13/25 of our subjects showed at least one EP that revealed a CNS involvement. The electrophysiological alterations were not correlated either with subject age or with disease duration. Multimodal EPs enabled us to demonstrate that CNS involvement in myotonic dystrophy is important and mainly affects the visual and auditory system.

Adult↗
PubMed1992

Accompanying symptoms of cluster attacks: their relevance to the diagnostic criteria.

Two-hundred-and-fifty-one consecutive cluster headache (CH) patients referred to the Pavia and Parma Headache Centers were evaluated in order to verify the presence and recurrence of one or more autonomic symptoms. Data obtained show that in 2.8% of patients cluster attacks were not accompanied by localized autonomic symptoms, thus confirming the report of Ekbom. We observed a high prevalence of photophobia, nausea and vomiting. The IHS diagnostic criteria for CH may need to be modified. The high frequency of "general" autonomic symptoms seems to suggest a component of "central" drive in the physiopathology of cluster headache.

Adult↗
PubMed1992

Hemicrania continua: a case responsive to piroxicam-beta-cyclodextrin.

The case of a 53-year-old woman is described, who since the age of 38 years had been suffering from a unilateral headache that was at first remitting, but then evolved into an unremitting course. The headache was burning in quality, located in the left forehead and face, and was accompanied by mild ipsilateral autonomic symptoms. The clinical picture, as well as the absolute response to indomethacin, suggested a diagnosis of hemicrania continua. The presence of mild gastric discomfort on continuous indomethacin administration made us transfer the patient to another NSAID (piroxicam-beta-cyclodextrin). With this drug, complete relief and good tolerability was obtained.

Chronic Disease↗
PubMed1992

Central analgesic activity of ibuprofen. A neurophysiological study in humans.

Ibuprofen is a widely used non-steroidal anti-inflammatory drug (NSAID). Inhibition of prostaglandin biosynthesis is considered to be the main mechanism of action of this substance. Recently, a central analgesic activity was described in an experimental study. In order to explore the possibility that ibuprofen induces analgesia at central level in humans, we investigated, in a double-blind design, the effects of orally-given 600 mg granular ibuprofen or placebo on nociceptive flexion reflex in normal volunteers. Ibuprofen produced a significant increase, as compared to placebo, in the threshold of the nociceptive reflex. The ratio between subjective pain threshold (Tp) and reflex threshold (Tr) was unchanged after either ibuprofen or placebo administration, indicating that Tp strictly paralleled Tr. These results indicate that ibuprofen displays a central antalgic activity in humans. Different supraspinal structures are probably involved, but the exact mechanisms are still to be clarified.

Administration, Oral↗
PubMed1992

Electrically elicited short and long-latency responses of intrinsic hand muscles in hereditary ataxias. Effects of isometric and ballistic isotonic voluntary contractions.

Short- and long-latency responses (HR and LLR) from thenar muscles were studied in patients with Friedreich's ataxia and pure cerebellar ataxia with later onset by applying electrical stimuli on the median nerve at the wrist. HR and LLR were examined during two different voluntary activities of the opponens pollicis muscle: isometric ("hold") and isotonic ballistic ("move") conditions. A preliminary conventional study of motor and sensory conduction of the median nerve was also carried out. Patients with Friedreich's ataxia had reduced or absent HR and LLR. Furthermore, those who preserved both responses had prolonged HR-LLR interpeak latency. All patients with Friedreich's ataxia also showed peripheral nerve conduction abnormalities, mainly in sensory fibers. These data can be accounted for by the widespread degeneration of many neural structures in this disorder. No abnormalities in HR were observed in pure cerebellar ataxia with later onset, whereas LLR was grossly enlarged in most patients, notably during "move" condition. Since cerebellar structures (especially the cerebellar cortex) are the only ones involved in this disorder, the cerebellum may play a role in modulating LLR. In particular, this effect could be more evident in isotonic ballistic movements.

Adolescent↗
PubMed1991

Cluster headache. Recent developments in clinical characterization and pathogenesis.

The preliminary results of some new studies on cluster headache (CH) point to: (a) the existence of a form, secondary episodic CH, which should be included in the classification of headache; (b) the significant role played by air temperature variations and the number of daylight hours on the onset of CH active periods. Data from the evaluation of pupil response to corneal stimuli suggest a widespread alteration of the pain/autonomic integrative processes at the level of the central nervous system. Finally, data on new preventive (i.e., verapamil and ozone) and symptomatic (i.e., hyperbaric oxygen and sumatriptan) treatments are reported.

Autonomic Nervous System↗
PubMedDate not supplied

[Automatic analysis of M.U.A.P.s (author's transl)].

The authors have studied the Motor Unit Action potentials derived from Extensor Digitorum Brevis and tibialis anterior muscles in normal subjects, using a new method of automatic analysis by means of a digital computer. In the light of the results they have obtained they discuss the validity and the sensitivity of the method as well as the opportuneness of the choice of the muscular region to examine when it comes to determining subclinical or "border-line" cases.

Action Potentials↗
PubMedDate not supplied

Electrophysiological study on jaw-opening reflex recorded from digastric muscle in Parkinson's disease and primary cranial dystonias.

We investigated digastric reflex excitability in normals and in patients with extrapyramidal disorders such as primary cranial dystonias and Parkinson's disease. Relationships between exteroceptive suppression of masseter muscle and digastric reflex were also investigated in some cases. Digastric reflex hyperexcitability was observed in dystonic patients when compared to normals and parkinsonian patients. Furthermore, some patients with cranial dystonia presented absence of exteroceptive suppression reflex in masseter muscle with enlarged digastric response. These results indicate hyperexcitability of the digastric reflex and abnormal agonist-antagonist muscle co-contraction in chewing reflexes of patients with cranial dystonias. This shows that digastric reflex is an important electrophysiological investigation to explore the physiopathological mechanisms of primary cranial dystonias.

Aged↗
PubMedDate not supplied

Cognitive and neuroradiological findings in myotonic dystrophy.

Cognitive functions were investigated in 37 patients with myotonic dystrophy (MD) and correlated with clinical and neuroradiological variables. The whole cognitive performance was at a low-average level; in about 1/3 of the subjects, in fact, the scores at the neuropsychological tests were below the normal range. There was a consistent trend for patients with inheritance on maternal side to perform worse on Wechsler verbal score and to present cerebral atrophy. In 7 out of 12 subjects focal white matter lesions were found at nuclear magnetic resonance. The significance of these findings and its relation to cognitive performance are discussed.

Adult↗
PubMedDate not supplied

Local venous lactate changes and spectral analysis of surface EMG during fatiguing isometric efforts in intrinsic hand muscles.

In this study relationships between local venous lactate concentrations and power spectrum changes in surface EMG due to fatiguing isometric contractions were investigated. Two different isometric efforts of the opponents pollicis muscle, 25% and 50% of maximum voluntary contraction, were examined. In 25% of maximum voluntary contraction no changes in local venous lactate were observed, whereas mean power frequency values of surface EMG shifted significantly towards lower frequencies. On the contrary, in 50% of maximum voluntary contraction lactate significantly increased and was related to the mean power frequency shifts of the surface EMG. These data suggest that lactate plays a role in muscle fatigue only in a limited intensity range of isometric muscle contractions.

Adult↗