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Biomedical subjects

M Pini

Publications and source records attributed to M Pini.

At least 73 records · Page 4Linked to original sources

In vitro and in vivo effects of adrenaline and phentolamine on platelet function.

In vitro and in vivo effects of adrenaline (ADR) on platelet aggregation, on platelet factor 3 (PF3) availability and on platelet factor 4 (PF4) release were studied in man. Inhibitory action of an alpha-blocker, phentolamine (PHEN) was investigated in the same conditions. The threshold concentration (TC) of ADR inducing the typical two-phase response in aggregation tests when added to platelet-rich plasma (PRP) varied in different pools of plasma, but always induced an evident PF4 release and increased PF3 availability. A further increase in both parameters was obtained with higher concentrations but without any significant dose/response correlation. Adding PHEN alone to PRP did not induce platelet aggregation or modify PF4 release induced by stirring, but it reduced PF3 availability. On the other hand, PHEN prevented the effects of ADR in different platelet tests, at appropriate concentrations. Intravenous infusion of ADR lowered the TC, and increased PF3 availability and PF4 release. In vivo administration of PHEN, in contrast, increased TC and reduced PF3 availability, while PF4 remained unchanged.

Blood Platelets↗

Inherited platelet abnormalities associated with low factor VIII activity in the same family.

Six of eight examined members belonging to two generations of the same (NEG-TUR) family were shown to have functional changes in platelets and/or a moderate decrease of factor VIII activity (FVIII:C) in plasma, with normal values of factor VIII-related antigen (VIII R:AG). Platelet defects (mainly a reduced PF3 availability, present in five patients) and factor VIII decrease were combined differently in individual members. Only two male members with both the PF 3 and FVIII:C defects had moderate haemorrhagic symptoms following traumatic injuries. One of them had also an absent adhesiveness to glass, the other one an absent adhesiveness to collagen and a reduced platelet aggregation by ADP and by collagen. Bleeding time, platelet function tests (in the other members), and routine coagulation tests were within normal range; ristocetin aggregation was also normal in all members. We think that two inherited defects, a mild haemophilia A and a "sui generis" thrombocytopathy, co-exist in this family.

Adolescent↗

Impaired fibrin formation in advanced cirrhosis.

The process of fibrin formation was systematically in 25 patients with severe alcoholic cirrhosis. Results of functional tests are reported. A significant lengthening of the thrombin time was found which could not be completely attributed either to hypofibrinogenaemia or to an increase in physiological anticoagulants or to the presence of pathological antithrombins. A defect in fibrin polymerization was seen in the absence of significant levels of antipolymerizing agents. Indirect evidence pointed to an abnormal fibrinogen function. This was mainly suggested by the "polymerization curves" of mixtures of normal and pathological plasmas and the changes in physico-chemical properties of the clot (optical and elastic properties; tensile strength). Altered synthesis in hepatocytes may lead to an "acquired dysfibrinogenaemia" in the late stages of liver cirrhosis, although alteration of a normal fibrinogen molecule after secretion cannot be definitely excluded.

Adult↗

Duplex ultrasound diagnosis of symptomatic proximal deep vein thrombosis of lower limbs.

Real time ultrasound (US) was used to examine 165 consecutive inpatients with clinically suspected deep vein thrombosis of lower limbs. In order to evaluate accuracy, the results of non-invasive techniques were compared with ascending venography, performed in all patients. Assessment included only femoro-popliteal veins, because of difficulty in visualizing calf vein with US. Diagnosis of thrombosis was based on noncompressibility of the examined veins; pulsed Doppler provided further information by evaluating blood flow. In our series Duplex ultrasound was very accurate in detecting acute thrombosis of the proximal veins, sensitivity being 97% and specificity 98%. With US it is also possible to detect conditions that mimic deep vein thrombosis, such as muscular rupture, hematoma, popliteal cyst or compressive tumors. In conclusion US is considered a valid alternative to contrast venography in the diagnosis of proximal vein thrombosis of lower limbs.

Adolescent↗

Warfarin induced dermatitis and venous thrombosis in a patient with Protein S deficiency.

A case of warfarin-induced dermatitis in a 79 year-old patient with Protein S deficiency is described. Both total Protein S antigen and free Protein S were moderately reduced (about 50%). The skin lesion did not progress to frank necrosis and it was associated with elevated creatin phosphokinase (CPK) levels in plasma and with thrombosis of the anterior tibial vein localized to the area of dermatitis (probably warfarin-induced deep venous thrombosis). After warfarin withdrawal and beginning of heparin therapy, serum CPK rapidly normalized and the skin lesion improved.

Aged↗

Low molecular weight heparin (Alfa LHWH) compared with unfractionated heparin in prevention of deep-vein thrombosis after hip fractures.

Efficacy and safety of a low molecular weight heparin (Alfa LMWH) was compared with unfractionated heparin (UFH) in the prevention of post-operative venous thromboembolism after hip fractures. Forty-nine patients were randomized to treatment with Alfa LMWH 7500 anti-Xa coagulometric units twice daily or with UFH 5000 IU t.i.d. Screening for thrombosis was performed with 125-I-fibrinogen leg scanning and strain-gauge plethysmography. Positive results were confirmed by venography. Five patients in the Alfa LMWH group (20 per cent) developed venographycally proven deep vein thrombosis (DVT) versus seven (29 per cent) in the UFH group. One pulmonary embolism and two deaths occurred in the UFH group and none in the LMWH group. No differences in haemorrhagic complications and blood loss indices were observed. Alfa LMWH appears to be a promising drug for prevention of venous thromboembolism after orthopaedic surgery. A "flexible" schedule of administration is proposed on the basis of the results of plasma anti-Xa assays.

Aged↗