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Biomedical subjects

M Toldo

Publications and source records attributed to M Toldo.

9 recordsLinked to original sources
PubMed1987

Relevance of platelet factor four (PF4) plasma levels in multiple sclerosis.

In order to study the role of platelets in Multiple Sclerosis (MS) we assessed, in a group of patients during a quiescent phase of the disease, the plasma levels of beta-thromboglobulin (beta-TG) and platelet factor four (PF4) both in absence of treatment and during administration of aspirin (ASA) at the dose of 50 mg/daily. In the MS patients studied, the basal plasma levels of beta-TG and PF4 were significantly higher than in control subjects. The increase in the beta-TG plasma levels occurred independently of the age, sex and severity of the disease, whereas the modification in the PF4 plasma levels was significantly correlated with the severity of the disease. Administration to the patients of ASA, at the dose that does not affect prostacyclin production, determined a decrease of beta-TG in 77% of the patients. Mean PF4 plasma levels remained unchanged. These results suggest that PF4 in the plasma of MS patients may originate not only from the platelets but also from the mast cells following platelet aggregating factor (PAF) stimulation and immunocomplex formation.

Adult↗
PubMed1986

Platelet activity in cluster headache.

Platelets are known to be activated in common or classic migraine both during the attack and in headache-free periods. Platelet behavior is less well known in cluster headache. We have investigated beta-thromboglobulin (beta-TG) and platelet factor four (PF4) plasma levels, markers of in vivo platelet activation, in patients during remission and during bouts of cluster headache with and without pain. The results indicated that statistically significantly higher levels of beta-TG and PF4 occur in the patients during the remission period when compared with the control subjects. Such high levels seemed to persist between paroxysmal episodes in cluster periods. However, during the attacks of cluster headache beta-TG and PF4 plasma levels decreased by 42% and 50%, respectively, in comparison with plasma concentrations measured outside of attack. Thus, although platelet activation also occurs in patients with cluster headache, the attack as such seems to be characterized by a marked reduction in platelet activation.

Adult↗
PubMed1985

Platelet behavior in patients with TIA: responsiveness to small doses of aspirin.

To study platelet role in cerebrovascular disease, beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) plasma levels, indices of in vivo platelet activation, were assayed in a group of patients affected by cerebral ischemic attack (transient ischemic attack; TIA). Determinations were carried out within 1 month from the ischemic event and following short-term (1 month) and long-term (1 year) daily administration of low doses (50 mg) of aspirin (ASA). After the cerebral ischemic event, beta-TG and PF4 plasma levels were elevated. beta-TG and PF4 plasma levels did not decrease after 1 month of treatment with ASA and significantly increased in all the patients after 1 year. Such a trend can perhaps be related to the natural course of the disease and associated with the possible occurrence of collagen-induced platelet activation in cerebrovascular patients. Data suggest that although platelet activation occurs in TIA-affected patients, the high levels of beta-TG and PF4 may not be adequate parameters for evaluation of TIA relapses and ASA efficacy.

Adult↗
PubMed1985

Drugs and platelet activation in migraine and transient ischemic attacks.

In order to study the role of platelets in migraine and cerebrovascular disease, beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) plasma levels, indices of in vivo platelet activation, were assayed in two groups of patients suffering from migraine (common/classic and classic/complicated migraine, respectively) and in one group suffering from transitory ischemic attacks (TIAs). Plasma determinations were carried out in the absence of treatment and during the administration of aspirin (50 mg/daily) and flunarizine (10 mg/daily). Platelet activation was found in patients suffering from TIA; patients affected by classic and complicated migraine showed a high incidence of activation, in comparison with common migraine sufferers, also in headache-free periods. Administration of aspirin (ASA) was more effective than flunarizine in inducing a decrease in beta-TG and PF4 plasma levels in migraineurs. Aspirin, however, did not affect platelet activation in subjects suffering from ischemic attack even though we did not observe any relapse after one year of treatment. The different effect of ASA in TIAs and migraine indicates that the platelet activation in TIA patients is due not only to cyclo-oxygenase pathway but also to other in vivo pathways.

Adult↗
PubMedDate not supplied

Study of platelet activation in migraine: control by low doses of aspirin.

Although platelet activation is known to occur during migraine attacks, the cause-effect relationship remains to be determined. This problem was approached by studying the possible occurrence of platelet activation in vivo in headache-free periods of subjects affected by common or classic migraine and, subsequently, by verifying the possibility of its pharmacological control through administration of a classic anti-aggregation drug such as aspirin (ASA). The plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4), indices of the occurrence of platelet activation in vivo, were therefore first assayed in both groups of migraine sufferers in the absence of therapy and then during the administration of aspirin (50 mg/daily). In the group of 15 patients affected by classic migraine, basal plasma levels of beta-TG and PF4 were significantly higher than control subjects. On the other hand, only beta-TG plasma levels were significantly higher in the group of 18 patients affected by common migraine. Patients suffering from classic migraine showed a high incidence of platelet activation (greater than 90%) in comparison with common migraine patients (approximately 33%). This suggests that platelet activation occurs in vivo in migrainous patients also during headache-free periods. Administration of aspirin to the patients affected by common and classic migraine caused a decrease in plasma beta-TG and PF4 concentration. Consequently, pharmacological treatment with aspirin in adequate dose may prove to be helpful in diminishing the vascular side-effects known to occur in migraine sufferers.

Adult↗
PubMedDate not supplied

Platelet alpha granule secretion in cerebral ischemia: effect of short and long term low dose aspirin treatment.

The effect of short and long-term therapy with aspirin (50 mg/day) on platelet alpha granule secretion was studied in 11 healthy controls and 57 patients suffering from transient cerebral ischemic attacks (TIA) with and without accompanying diabetes and hypertension. Plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF 4) were measured as indicators of platelet alpha granule secretion. beta-TG and PF 4 levels were increased following cerebral ischemia. Aspirin treatment failed to suppress plasma levels of both proteins when measured a month and then a year after initiation of treatment. Therefore, these proteins may be poor indicators of platelet inhibition by aspirin.

Adult↗