Biomedical subjects

Giuseppe Amabile

Publications and source records attributed to Giuseppe Amabile.

5 recordsLinked to original sources

PubMed2003

Effect of painful heterotopic stimulation on the cutaneous silent period in the upper limbs.

OBJECTIVE: To evaluate the effect of heterotopic painful stimulation (HPS) on the cutaneous silent period (CSP) and the withdrawal flexor reflex (WFR) in the upper limbs, in an attempt to better identify the nociceptive component of the CSP and its functional relationship with the flexor reflex. METHODS: The CSP at different stimulus intensities, the WFR and the H/M ratio were studied in 12 healthy adults. Neurophysiological measurements were recorded in the following 4 conditions: (1) control session; (2) non-painful session (dipping hand in water at 25 degrees C); (3) painful (cold pressor test, CPT); and (4) after-effect (3-8 min after taking hand out of water at 5-6 degrees C). RESULTS: During the CPT, the duration of the high-threshold CSP was approximately 23% shorter than the baseline value, the high-threshold CSP latency was approximately 10% longer than the baseline value, and the mean RIII reflex area was approximately 40% smaller than the baseline reflex area (all P<0.05). A significant correlation was found between the percentage decrease in the CSP duration and the WFR area (r=0.61, P<0.05). CONCLUSIONS: Our findings indicate that the HPS specifically inhibits both the high-threshold CSP and the WFR, thereby providing further evidence that these cutaneous reflexes are functionally and anatomically related, and that they represent different aspects of a complex nocifensive response.

Adult↗

PubMed2003

Trigemino-cervical-spinal reflexes in humans.

INTRODUCTION: Electrical stimulation of the supraorbital nerve (SON) induces late reflex responses in the neck muscles; these responses are hypothesised to be polysynaptic reflexes participating in a defensive withdrawal retraction of the head from facial nociceptive stimuli. Such responses may extend to the proximal muscle of the arms. OBJECTIVE: (1) to investigate reflexes in the upper limb muscles (trigemino-spinal responses, TSR) and their relationship with trigemino-cervical responses (TCR); and (2) to identify the nociceptive component of such reflexes and their functional significance. METHODS: Reflex responses were registered from the semispinalis capitis and biceps brachii muscles after electrical stimulation of the SON in 12 healthy subjects. The sensory (ST), painful (PT) and reflex thresholds, the latency and area of the responses, the effect of heterotopic painful stimulation (HTP), the recovery cycle as well as the effect of the expected and unexpected stimuli were measured. RESULTS: Stable reproducible TCR and TSR responses were identified at 2.5+/-0.4 x ST, which corresponded exactly to the PT in all the subjects. The TCR and TSR areas were markedly reduced after HTP. The recovery cycle of the TSR area was faster than that of the TCR. Repeated rhythmic stimulation failed to induce progressive reflex suppression. CONCLUSIONS: These results confirm the nociceptive nature of the TCR and indicate that the biceps brachii response (TSR) has the same nocifensive significance as the posterior neck muscle responses. TCR and TSR are mediated different polysynaptic pathways The presence of trigemino-cervical-spinal responses in our study clearly indicates that there is a reflex interaction between nociceptive trigeminal afferents and both upper and lower cervical spinal cord motoneurons.

Adult↗

PubMedDate not supplied

Preprogramming motor dysfunction in paroxysmal kinesigenic choreoathetosis.

Paroxysmal kinesigenic choreoathetosis (PKC) is characterized by abnormal involuntary movements precipitated by sudden movement. As a result, a possible impairment of cerebral organization of voluntary motor activity is hypothesized in PKC. We examined a 14-year-old boy affected by a sporadic form of PKC, adopting a multimodal psychophysiological approach, including P300, contingent negative variation (CNV) and a specific paradigm for the study of movement related potentials (MRPs). Recordings were made before and after phenobarbital therapy. No changes were observed in the non-motor parameters (P300 and early wave of the CNV), whereas the premotor CNV component and the electrophysiological components, reflecting the preprogramming activity of a voluntary motor act, showed selective modifications induced by the anticonvulsant therapy. Our PKC patient presents a disorder of temporal organization of a voluntary motor response to a stimulus. Both a clinical improvement and normalization of motor-related electrophysiological anomalies were observed during phenobarbital (PB) therapy.

Adolescent↗

PubMedDate not supplied

Personality and the effects of acute alcohol intake. A contingent negative variation study in healthy subjects.

This study investigates the relationship between blood alcohol concentrations (BACs) and contingent negative variation (CNV). Fourteen healthy subjects were divided on the basis of their personality profiles--the Minnesota Multiphasic Personality Inventory (Hs+Hy+D/3)--into a high score (HS) and low score (LS) subgroup. The CNV was recorded using a choice-reaction time (RT) task. CNV recording was performed in two conditions: inter-stimulus intervals (ISIs) of 1500 ms and 2500 ms at three different BACs (0.3, 0.5 and 0.8 g/L) after acute alcohol administration. At the high BAC (0.8 g/L), both subgroups showed a reduced CNV amplitude area and a longer RT (p<.05) in both ISI conditions. No effects either on the CNV or on the RT were observed at the low BAC (0.3 g/L). At the intermediate BAC (0.5 g/L), the HS subgroup displayed an increased CNV amplitude (p<.05), not accompanied by a significantly longer RT (short ISI condition), and a reduced late CNV (p<.05) with a longer RT (p<.05) (long ISI condition). In the LS group, only a longer RT was observed in the long ISI condition. CNV modifications point to an individual, apparently personality-related, threshold of sensitivity to different alcohol levels.

Adult↗

PubMedDate not supplied

Early diagnosis in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL): the role of MRI.

The aim of our work was to evaluate the early presence of white matter changes on magnetic resonance imaging (MRI) in young asymptomatic children of patients with full-blown cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) in whom DNA analysis revealed a Notch3 Cys146Tyr missense mutation on chromosome 19. Brain MRI was performed in all subjects using axial and coronal spin-echo proton density and T2-weighted images, axial fluid-attenuated inversion recovery (FLAIR) and sagittal and axial T1-weighted images. In asymptomatic subjects with Notch3 gene mutation, MRI showed small T2 hyperintense foci in periventricular and subcortical white matter. Routine use of MRI in the initial phases of a CADASIL diagnostic work up and the subsequent recognition of early abnormal findings in asymptomatic subjects may lead to prompt diagnosis of the disease in these patients. Moreover, these findings suggest that genetic screening is warranted in the presence of a suspect clinical history with specific MRI abnormalities.

Adult↗