Biomedical subjects
Publications and source records attributed to M Guerrini.
We have demonstrated how conservation time affects whole blood filterability. The filtration index decay appears just after withdrawal and is present, with different characteristics, both at room temperature and at 37 or 4 degrees C. It is absolutely necessary to take measurements immediately after blood withdrawal.
We have counted the different types of blood cells before and immediately after filtration. During filtration, an almost equal quantity of each type of cells remained in the filter, with a slightly higher percentage of leucocytes. The problem regarding occlusion of filter pores should be considered in the light of these findings.
A clinical study on the effects of the normovolemic hemodilution on hemorheological and peripheral hemodynamic parameters has been carried out in patients with peripheral obliterative arterial disease. Two sessions have been performed: the acute test consisted in daily normovolemic hemodilutions for a period of 7 days in 10 patients with the determination of hemorheological and peripheral hemodynamic parameters before and after each treatment. A chronic study was then carried out in 8 patients by applying weekly normovolemic hemodilutions, by evaluating the hemorheological parameters as in the first session and by measuring the peripheral hemodynamic parameters at the beginning, after 5 weeks and at the end of the treatment. The results are reported and the possible mechanism of action of normovolemic hemodilution is discussed.
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The infusion of isoxsuprine was followed by an increase of heart rate and calf blood flow and by a decrease of arterial diastolic pressure and blood viscosity both in normal controls and patients with peripheral obstructive arterial disease. The pre-treatment with a non-selective beta adrenoceptor blocker (propranolol) canceled all the isoxsuprine-dependent changes, while the pre-treatment with a selective beta adrenoceptor blocker (metoprolol) abolished only tachycardia and did not influence the increase of calf blood flow and the decrease of blood viscosity. These findings indicate the different role of vascular beta receptors in the regulation of muscular blood flow and suggest the pharmacologic possibility to unmask the beta2-dependent vasodilation.
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Prostaglandin A1 (PGA1) was infused at the rate of 1/microgram/kg/min in 10 patients with decompensated heart failure under conditions of water loading (5 patients) or water deprivation (5 patients). During water loading, PGA1 increased urinary excretion of sodium, potassium, chloride, calcium, and magnesium, as well as free-water clearance. During water deprivation, it increased free-water reabsorption. Gomerular filtration rate was increased slightly by PGA1 only when it was given with an infusion of hypertonic mannitol during water deprivation. This selective action of PGA1, which increased the excretion but not the reabsorption of free water, suggests its use to correct certain hypo-osmolar conditions. The site of action of PGA1 on the kidney seems to be in the tubules and mainly in the proximal tubules. These findings might be important in the understanding of the role of renal prostaglandins.
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Cinnarizine, a drug capable of improving blood flow, was studied for its action on blood viscosity and its main components in patients affected by peripheral obliterative arterial diseases (POAD). Both acute and chronic administration of the drug diminished the increased whole-blood viscosity in patients, without affecting plasma and serum viscosity, hematocrit, plasma fibrinogen concentration, and plasma osmolality. Since cinnarizine also led to a significant increase of peripheral muscular blood flow, it was hypothesized that this action may be due to an increased deformability of the red cells, and may play a considerable role in the therapeutic approach to POAD.
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1 Blood viscosity is thought to be a major factor in disorders of the peripheral circulation. 2 Ten patients with obliterative arterial disease received an infusion of isoxsuprine of 20 micrograms kg-1 for 30 min. The infusion was followed by a highly significant and prolonged fall in blood, plasma and serum viscosity, in haematocrit and in plasma fibrinogen concentration. Blood lipid levels were also studied: total lipids and total cholesterol did not alter; triglyceride level was significantly lowered at the end of, and after, drug infusion. 3 There was no change in blood, plasma or serum viscosity in the four patients receiving a control infusion 2 days before the infusion of isoxsuprine. 4 The relationships between lowered viscosity and increasing peripheral tissue perfusion are discussed.
Two-months' administration of 2.5 mg/day indapamide, preceded and followed by 2 weeks of a placebo, led to a significant fall in pressure values and normalisation of diastolic pressure in a high percentage of 47 subjects, mostly with essential hypertension, in a controlled multi-centre trial. Absence of toxic effects, tolerance and therapeutic activity at low doses recommend the drug for most cases of arterial hypertension.
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