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Biomedical subjects

G Sandrini

Publications and source records attributed to G Sandrini.

At least 73 records · Page 4Linked to original sources
PubMed1987

Ritanserin, a serotonin-S2 receptor antagonist, does not prevent 5-hydroxytryptophan-induced beta-EP, beta-LPH and cortisol secretion.

Ritanserin, a new serotonin antagonist selective upon S2 receptor subclass is available. Thus, in order to better define the positive control of serotoninergic pathway on proopiomelanocortin (POMC)-related peptide release, a group of 7 healthy male volunteers has been submitted to a 5-hydroxytryptophane (5-OH-TP) test (200 mg p.o.) before and after 4 days Ritanserin pretreatment. Plasma beta-endorphin (beta-EP), beta-lipotropin (beta-LPH) and cortisol levels were measured hourly for 4 h after each 5-OH-TP loading. Hormonal levels were measured by specific RIAs on extracted (cortisol) and chromatographed (beta-EP and beta-LPH) plasma samples. Basal plasma concentrations of the three hormones were unchanged by Ritanserin pretreatment. Similarly, the integrated areas of beta-LPH, beta-EP and cortisol release in response to 5-OH-TP remained unaffected by the receptor blockade. These data confirm that serotonin-acting drugs are able to stimulate POMC-related peptide release and indicate that such interaction is not mediated through S2 receptor subclass.

5-Hydroxytryptophan↗
PubMed1987

Postprandial and orthostatic hypotension in Parkinson's disease.

In this study, the 24-hour pattern of blood pressure (BP), heart rate, and urinary catecholamine (CA) excretion and the response of BP and plasma CA to the tilt test have been investigated in 13 untreated patients affected by Parkinson's disease (PD) and in 11 age-matched healthy controls. Seven of the 13 PD subjects showed a fall of supine systolic BP greater than that in controls (ie, exceeding 20% of the preprandial value). A significant relationship was found in the PD group between the degree of postprandial hypotension and the 24-hour mean value of dopamine excretion. Eight PD subjects also showed orthostatic hypotension during the tilt test (performed in the morning hours) and in the postprandial phase. Basal norepinephrine plasma levels of PD patients, as well as their percentage increases on standing, were within the range of the controls. These data suggest the existence of a subtype of PD patient, characterized by a widespread impairment of cardiovascular responsiveness and bordering on syndromes of autonomic failure such as progressive autonomic failure or multiple system atrophy, or both.

Aged↗
PubMed1987

Comparative efficacy of cyclandelate versus flunarizine in the prophylactic treatment of migraine.

In a double-blind, parallel-group randomised trial of 3 months' duration, the efficacy of cyclandelate 800 mg twice daily in migraine prophylaxis was compared with that of flunarizine 5mg daily in 40 patients. In comparison with placebo and baseline values, both drugs significantly relieved symptoms of migraine as assessed by indices of pain total index, headache index, analgesic consumption and number of migraine days. Patients taking flunarizine experienced side effects such as drowsiness, weight gain and asthenia, while the most common complaint reported with cyclandelate was gastric upset. These results suggest that cyclandelate may be a useful alternative in migraine prophylaxis.

Adolescent↗
PubMed1986

Evidence for serotonin-S2 receptor involvement in analgesia in humans.

The possible analgesic activity of ritanserin (a new very selective and potent serotonin-S2 antagonist) was studied (double-blind) in humans. A significant increase in nociceptive flexion reflex threshold and subjective pain threshold was observed after five days of treatment, while treatment with placebo did not induce any change. The effects of ritanserin were not reversed by either naloxone or saline (double-blind) administration. Our data suggest a possible role of serotonin-S2 receptors in analgesia.

Adult↗
PubMed1986

Dermorphin inhibits spinal nociceptive flexion reflex in humans.

Dermorphin (D) is a potent opiate-like peptide isolated from the skin of some species of frogs. Experimental studies in animals indicate that D has a potent antinociceptive effect, while no investigation exists about its analgesic properties in humans. Our study shows that i.v. infusion of 0.16 mg/kg D induces a marked and long-lasting increase in the threshold of nociceptive flexion reflex in healthy volunteers. This effect is also evident in a complete chronic spinal subject, showing that D depresses the nociceptive transmission mainly acting at spinal level. Naloxone, while fully antagonizing the effects of morphine and enkephalin analogue, is able to reverse only partly (ca. 50%) the depressive effect of D on nociceptive spinal reflex. This fact may suggest that D interacts with different spinal opiate receptor populations in inducing analgesia.

Adult↗
PubMed1986

Carbamazepine poisoning: a case report.

In a case of acute intoxication produced by carbamazepine overdose ataxia and cyclic coma were the salient features. The mechanisms underlying these symptoms are discussed. Some peculiarities such as breathing irregularities and microhematuria are also described.

Adolescent↗
PubMed1986

Electroretinographic and visual evoked potential abnormalities in myotonic dystrophy.

Pattern visual evoked potentials (VEPs) and electroretinograms (ERGs) were recorded in 20 patients with myotonic dystrophy. Thirteen out of 20 cases presented both VEP and ERG abnormalities, 3 only ERG alterations, 2 only abnormal VEPs. A significant inverse correlation between P100 latencies and b1 wave amplitude was observed, while N1-P100 and b1 wave amplitude exhibited a parallel change. These data suggest that retinal abnormalities may have a role in inducing subclinical visual pathway alterations in myotonic dystrophy.

Adolescent↗
PubMed1986

Effects of L-5HTP with and without carbidopa on plasma beta-endorphin and pain perception: possible implications in migraine prophylaxis.

L-Tryptophan (L-TP) has been used in migraine and other pain conditions. The mechanism underlying the analgesic effect is still partly undefined. In this study the effects of subchronic administration of L-5-hydroxytryptophan (L-5HTP) (with and without carbidopa) on plasma beta-endorphin (beta-EP) levels and subjective pain threshold and tolerance were investigated in seven healthy volunteers. To measure also an objective indicator of pain, the nociceptive flexion reflex threshold was studied. L-5HTP treatment with and without carbidopa administration increased beta-EP levels significantly (p less than 0.05). L-5HTP plus carbidopa induced an increase in beta-EP significantly (p less than 0.05) greater than that induced by L-5HTP alone. Neither the subjective pain threshold and tolerance nor the RIII threshold was modified by either treatment. Our data seem to point to the existence of a complex linkage between plasma opioid levels and pain perception.

Adult↗
PubMed1986

Effects of L-5HTP with and without carbidopa on plasma beta-endorphin and pain perception. Possible implications in migraine prophylaxis.

L-Tryptophan (L-TP) has been used in migraine and other pain conditions. The mechanism underlying the analgesic effect is still partly undefined. In this study the effects of subchronic administration of L-5-hydroxy-tryptophan (L-5HTP) (with and without carbidopa) on plasma beta-endorphin (beta-EP) levels and subjective pain threshold and tolerance were investigated in seven healthy volunteers. To measure also an objective indicator for pain, the nociceptive flexion reflex threshold was studied. L-5HTP treatment with and without carbidopa administration increased beta-EP levels significantly (p less than 0.05). L-5HTP plus carbidopa induced an increase in beta-EP significantly (p less than 0.05) higher than that after L-5HTP alone. Neither subjective pain threshold and tolerance nor RIII threshold was modified by either treatment. Our data seem to point to the existence of a complex linkage between plasma opioid levels and pain perception.

5-Hydroxytryptophan↗
PubMed1985

Effects of lisuride on blink reflex habituation in Parkinson disease.

The blink reflex presents a tendency to habituation (a gradual diminution of the amplitude of the response during repetitive stimulation). Electromyographic analysis of this reflex makes it possible to quantify this phenomenon. A lack of the habituation of the blink reflex is a typical feature of Parkinson disease. L-Dopa and amantadine, but not anticholinergic drugs, are able to partly reverse these abnormalities in blink reflex habituation to a normal pattern. Lisuride, a dopamine agonist with serotoninergic activity, has been recently proposed as antiparkinsonian agent. In our study we observed that lisuride has a positive effect on blink reflex habituation in Parkinson disease. A good correlation between the improvement of this electrophysiological parameter and clinical akinesia was seen. Mechanisms underlying the therapeutic effect of lisuride are complex, but this drug usually has a postsynaptic effect on D2 receptors. Our data suggest that these receptors play an important role in blink reflex habituation.

Adult↗
PubMed1985

Endorphin patterns within the headache spectrum disorders.

The role of opioid peptides in modulating the nervous system adaptability has been demonstrated recently; proopiomelanocortin (POMC)-related peptides, in particular, serve in pain perception, in adaptation to stress, and in modulating higher brain functions. Primary headaches, besides pain, involve neuroendocrine/autonomic/adaptive processes as well as mood and personality factors. The view that primary headaches can be taken as a possible model of POMC-related peptides dysfunction led us to evaluate the resting plasma and CSF peptide levels and their plasma changes in response to various stimuli affecting their release. The data obtained from basal and dynamic studies agree with the concept that primary headaches are sustained by opioid system disturbance. In particular the reduced release of endogenous opioids by anterior pituitary in response to physical, endocrine or pharmacological stimuli agrees with a weak adaptive ability of headache sufferers. This impairment of endorphin responsiveness could play a key role in headache susceptibility to environmental stimuli. Primary headaches constitute a wide, intriguing field, including several subgroups bordering on "ischemic" and behavioral/affective disorders. The development of neuroendocrine techniques could be a useful means for supporting the clinical criteria identifying subpopulations of headache sufferers.

Adrenocorticotropic Hormone↗
PubMed1983

Headache temporal patterns: towards a chronobiological model.

Rhythmical changes in terrain susceptibility and trigger occurrence can induce periodic temporal patterns in headache patients, with readily foreseeable frequency cycles of attacks. The impaired ability of biological functions to adjust to cyclic environmental changes represents the minus, the handicap, the increased risk of clinical symptomatology (headache); attacks occur when the precarious systems of these patients are forced by cyclical environmental stimuli towards phase shiftings or to cope with new levels of performance. A dyschronic hypothesis of primary headache must be based upon observations demonstrating that along with dysfunctions of the pain control systems there is also a vulnerability of the rhythmic physiological organization of CNS.

Adult↗
PubMed1983

Electromyographic investigation in early diagnosis of carbon disulphide neuropathy: a study on 216 workers with different degrees of exposure.

An electromyographic (EMG) investigation was performed on 216 workers of a viscose rayon plant with different degrees of exposure to CS2. In the light of the data supplied by the survey the AA. maintain that meedle EMG is able to detect, probably better than other test, changes of PNS even if they are very slight, and to select subjects having a higher risk of suffering from neuropathies. Nevertheless, also because of its sensitivity, EMG seems to be less specific than other electrophysiological parameters such as maximal motor conductions velocity (MMCV), that is significantly altered in exposed people. Muscular changes may be connected to a specific effect of CS2 less surely than MMCV change. However, they might be considered as pointing to a predisposition to PNS illness and it seems advisable to eclude these subjects from CS2 exposure.

Adult↗
PubMed1982

Insulin receptors in myotonic dystrophy: a study with mononuclear leucocytes and erythrocytes.

We evaluated insulin receptor activity on mononuclear leucocytes and erythrocytes in 9 patients with myotonic dystrophy and in 9 controls. The results demonstrated that in myotonic dystrophy: 1. insulin binding to specific receptors was significantly impaired (P less than 0.01) because of a reduction in the number of high and low affinity receptors. 2. the affinity constants were not significantly affected 3. there was no correlation between receptor activity, insulin behaviour and glucose tolerance. These data obtained in two different cellular systems suggest that the constant numerical reduction of insulin receptors was probably due to a systemic membrane defect, typical of myotonic dystrophy.

Adult↗