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Biomedical subjects

D Geroldi

Publications and source records attributed to D Geroldi.

At least 37 records · Page 2Linked to original sources

Action of piracetam and clonidine on different mitochondrial populations from hippocampus.

The maximum rate (Vmax) of some mitochondrial enzymatic activities related to energy transduction (citrate synthase, malate dehydrogenase, NADH-cytochrome c reductase (as total activity), cytochrome oxidase) and amino acid metabolism (glutamate dehydrogenase) were evaluated in non-synaptic (free) and synaptic mitochondria from rat brain hippocampus. Three types of mitochondria were isolated from rats subjected to single i.p. treatments with piracetam (300 mg.kg-1) or with clonidine (750 micrograms.kg-1). With respect to the enzymatic pattern of three types of non-synaptic and synaptic mitochondria, in hippocampus a different maximum rate of both NADH-cytochrome c reductase and cytochrome oxidase was observed, these activities in particular being lowest in the "synaptic heavy" mitochondrial subfraction than in the "synaptic light" one; in addition, other enzyme activities are different in the "free" as compared to both the "light" and "heavy" mitochondria. This confirms that in various types of brain mitochondria a different metabolic machinery exists. Acute treatment with piracetam decreased citrate synthase, glutamate dehydrogenase, NADH-cytochrome c reductase and cytochrome oxidase activities only in the "heavy" mitochondria obtained from synaptosomes. Acute treatment with clonidine decreased the citrate synthase, NADH-cytochrome c reductase and cytochrome oxidase activities only in the same type of mitochondria, i.e. synaptic "heavy" mitochondria. However, this drug increased the same enzymatic activities in "free" mitochondria, some of them being increased or decreased in "light" intrasynaptic ones. Therefore in vivo administration of piracetam mainly affects some specific enzyme activities (suggesting a specific molecular trigger mode of action) of the intrasynaptic mitochondria (suggesting a specific subcellular trigger site of action), the effect on enzyme activities by clonidine being more complex.

Animals↗

Immunoglobulin G antibodies to lymphadenopathy-associated virus in differently treated French and Belgian hemophiliacs.

Immunoglobulin G antibodies to lymphadenopathy-associated virus have been detected in two groups of French hemophiliacs and in one group of Belgian hemophiliacs, whose mode of treatment differed. Seropositivity was more frequent (58.9%) in patients heavily transfused with blood products of French and foreign origin than in less frequently transfused persons (10.3%). The Belgian group, treated only with local products, showed the lowest frequency of seropositivity (3.4%). In healthy French controls, 1 of 330 had antibody to the virus. The results indicate transmission of lymphadenopathy-associated virus via blood-derived products.

Antibodies, Viral↗

Prevalence of antibodies to lymphadenopathy-associated retrovirus in African patients with AIDS.

The presence of antibodies to lymphadenopathy-associated retrovirus (LAV) was determined by a radioimmunoprecipitation assay and by an enzyme-linked immunosorbent solid assay of sera from Zairian patients with the acquired immune deficiency syndrome (AIDS) in 1983. Thirty-five of 37 patients (94 percent) and 32 of 36 patients (88 percent), respectively, were seropositive by the two tests. In a control group of 26 patients, six (23 percent) showed positive results in these tests. Of these six control patients, five had clinically demonstrable infectious diseases and a low ratio of T4 to T8 lymphocytes. In addition, sera collected from a control group of Zairian mothers in 1980 were positive for LAV in 5 of 100 cases. Other serologic data suggest that LAV was present as early as 1977 in Zaire.

Acquired Immunodeficiency Syndrome↗

Enhanced antithrombotic mechanisms in patients with maturity-onset diabetes mellitus without thromboembolic complications.

Some haemostatic parameters have been evaluated in a group of rigorously selected patients with maturity-onset diabetes mellitus without thromboembolic complications and in apparently normal subjects of the same age before and after the venous occlusion test (VOT). In basal conditions diabetics had higher levels of AT III as biological activity and higher fibrinolytic and antifibrinolytic activities than controls. After VOT, F VIII R:Ag increased significantly in both groups, more markedly in controls than in diabetics, while F VIII: C showed no modification. Also AT III R:Ag increased after the test, but such variation was significant only in diabetics; on the contrary, the biological activity of AT III was always significantly decreased after the test. After VOT there were also in both groups highly significant increases in the fibrinolytic and antifibrinolytic activities. Finally, HbA1c levels directly correlated with AT III as biological activity before VOT, but with no other parameter either before or after the test. These data suggest the existence in patients with diabetes mellitus without thromboembolic complications of an activated protective mechanism against intravascular clotting.

Aged↗

[Effect of factor VIII concentrate on malondialdehyde release by normal human platelets].

It is well known that Factor VIII concentrates affect platelet function both "in vitro" and "in vivo" but the mechanism of their action is poorly understood. Therefore the aim of the present work was to investigate a possible effect of these concentrates on prostaglandin synthesis by platelets, measured as the amount of released malondialdehyde (MDA), which is an index of Thromboxane A2 production. Our data suggest that Factor VIII concentrates have no effect on MDA release by platelets and on its inhibition by aspirin and heparin. In conclusion the effect of Factor VIII concentrates on platelets is not mediated by an increased synthesis of prostaglandins.

Adult↗