Search PubMed⌕ Search

Biomedical subjects

G Ferretti

Publications and source records attributed to G Ferretti.

At least 253 records · Page 14Linked to original sources
PubMed1988

[The MRI sites functioning in 1987 in France. Results of a survey].

A study of the 23 MRI sites functioning in France at the end of 1987 provides an overall view of the organizational and economic aspects of these sites as well as an initial assessment of their activity in terms of the types of equipment used and the institutions, private or public, within which they have been set up.

Costs and Cost Analysis↗
PubMed1988

Altered properties of platelet membrane in childhood obesity.

Using 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5,hexatriene (TMA-DPH) as fluorescent probe, we have studied platelet membrane fluidity and thrombin induced exocytosis in ten obese children and fifteen controls. Our results indicate a decrease of membrane fluidity, as shown by an increase of fluorescence anisotropy, in platelets from obese patients in comparison with the controls. Associated with the changes in membrane fluidity, platelets of obese subjects showed a decreased sensitivity to thrombin stimulation.

Adolescent↗
PubMed1987

Modification of lipid composition of erythrocyte membranes in chronic alcoholism.

The lipid composition and microviscosity of erythrocyte membranes have been studied in chronic alcoholics with macrocytosis and minimal liver dysfunction. The findings have been compared with those obtained in subjects with macrocytosis not related to ethanol abuse. In all instances, macrocytosis was accompanied by an increased microviscosity of erythrocyte membranes, together with an increase of the cholesterol/phospholipid and of saturated/unsaturated fatty acids ratio. Both microviscosity and saturated/unsaturated ratio were significantly higher in alcoholics compared to subjects with macrocytosis not related to ethanol abuse. These findings confirm that altered lipid composition and fluidity of erythrocyte membrane may be observed in chronic alcoholics with minimal liver dysfunction, possibly due to the "stabilising" properties of ethanol - among a number of drugs- on biological membranes.

Adult↗
PubMed1987

Effects of exercise on maximal instantaneous muscular power of humans.

The maximal instantaneous anaerobic power (w), as determined during a high jump off both feet on a force platform, was measured on eight subjects starting from a resting base line; a base line of steady-state cycloergometric exercise requiring 30, 50, and 70% of individual maximum O2 consumption (VO2max); and a base line of maximal and supramaximal exercise (100 and 120% of VO2max). In addition, w was also measured during the VO2 transients from rest to each of the above work loads. Blood lactate concentration ([Lab]) was determined before and 8 min after the end of each priming load. After the onset of any priming load, w decreases with time reaching in 2 min a steady level that is lower the higher the VO2. For the three lowest work rates, the steady w level is unchanged by increasing the duration of the priming exercise up to 30 min. For low work levels, the decrease of w as a function of VO2 is essentially parallel to that of estimated muscle concentration of ATP ([ATP]). For work levels greater than 60% of VO2max involving a substantial accumulation of lactate, the decrease of w becomes smaller than the estimated drop of muscle [ATP]. This finding is tentatively attributed to an increase of either the mechanical equivalent or of the velocity constant of ATP splitting brought about by the lowering of intracellular muscle pH after lactate accumulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1987

Changes of membrane fluidity in erythrocytes of obese children: a spin label study.

Red blood cells depend on circulating lipoproteins for the turnover of membrane phospholipids. Thus abnormalities in lipid and lipoprotein metabolism are frequently associated with changes in composition and fluidity of erythrocyte membranes. Using the electron spin resonance technique we studied the physical state of erythrocyte membranes from 15 obese children with a body mass index ranging from 22.8 to 34 kg . m-2 and slight alterations of plasma lipids. The spin labels used, 5-doxylstearate and 16-doxylstearate, have shown an increase of the order parameter and of the correlation time, respectively. These observations indicate a decrease of fluidity at the surface and in the hydrophobic core of erythrocyte membranes from obese subjects. The results are statistically significant and they are discussed in relation to clinical aspects of childhood obesity. Studies on erythrocyte membrane molecular organization could represent a sensitive way to find out small metabolic alterations hardly detectable with compositional studies.

Adolescent↗
PubMed1986

[Budd-Chiari syndrome. Description of 2 cases].

The causes of Budd-Chiari syndrome are quickly reviewed with reference to the pathology described in series from various parts of the world. In the West the syndrome is caused by obstruction of the Inferior Vena Cava in its retrohepatic course with or without concomitant obstruction of the suprahepatic veins attributable to fibrous regression of the vessel wall and subsequent endoluminal thrombosis. In the Far East and South Africa the syndrome is caused by the presence of a thin fibrous septum obstructing the vein immediately upstream of the right atrium. Of the two cases of Budd-Chiari syndrome described, one presented high grade stenosis of the Vena Cava caused by fibrous regression of the vessel wall and the other a fibrous septum situated transversally to the lumen. The description of the first case is particularly interesting because before the clinical picture was correctly understood, a succession of major complications induced incorrect diagnosis and treatment. In contrast the second was a classic case of rapid diagnosis and successful treatment. The discussion of the two cases highlights the primary role currently played by abdominal echography with Doppler ultrasound, examination with lower cavography using a contrast medium in documenting a caval flow pathology of this kind. CAT scanning, arteriography of the Celiac tripod and closed hepatic needle biopsy appear to be much less decisive.

Adult↗
PubMed1986

Effect of chronic ethanol abuse on the physico-chemical properties of erythrocyte membranes in man.

Chronic alcoholics (greater than 150 g/day) showing minor serum and histological changes have been studied, compared to healthy non alcoholic subjects, and the following parameters have been considered: S. (Serum)cholesterol (CH), S.phospholipids (PH), S.folate level, and mean corpuscular volume (MCV). Erythrocyte ghosts have been studied for CH and PH content and membrane fluidity using diphenylhexatriene as a probe. All alcoholics showed decreased fluidity of red cell membrane with increased CH/PH ratio, even in patients showing normal MCV or minimal alterations of functional tests, suggesting that changes in red cell membrane fluidity represent an early sign of ethanol abuse. These likely reflect the diffuse interaction of ethanol with biological membranes. The administration of N5-Methyltetrahydrofolate produced an increase of membrane fluidity over the 3 weeks considered, associated with modest changes of MCV. The latter were delayed with respect to changes in fluidity. If changes of red cell membrane fluidity are a sensitive index of alcohol abuse, they could be a useful marker for detection and follow-up of chronic alcoholism.

Adult↗
PubMed1986

Physiological profile of world-class high-altitude climbers.

The functional characteristics of six world-class high-altitude mountaineers were assessed 2-12 mo after the last high-altitude climb. Each climber on one or several occasions had reached altitudes of 8,500 m or above without supplementary O2. Static and dynamic lung volumes and right and left echocardiographic measurements were found to be within normal limits of sedentary controls (SC). Muscle fiber distribution was 70% type I, 22% type IIa, and 7% type IIb. Mean muscle fiber cross-sectional area was significantly smaller than that of SC (-15%) and of long-distance runners (LDR, -51%). The number of capillaries per unit cross-sectional area was significantly greater than that of SC (+ 40%). Total mitochondrial volume was not significantly different from that of SC, but its subsarcolemmal component was equal to that of LDR. Average maximal O2 consumption was 60 +/- 6 ml X kg-1 X min-1, which is between the values of SC and LDR. Average maximal anaerobic power was 28 +/- 2.5 W X kg-1, which is equal to that of SC and 40% lower that that of competitive high jumpers. All subjects were characterized by resting hyperventilation both in normoxia and in moderate (inspired O2 partial pressure = 77 Torr) hypoxia resulting in higher oxyhemoglobin saturation levels in hypoxia. The ventilatory response to four tidal volumes of pure O2 was similar to that of SC. It is concluded that elite high-altitude climbers do not have physiological adaptations to high altitude that justify their unique performance.

Adaptation, Physiological↗
PubMed1986

Echo-Doppler velocimetry in the diagnosis of renal artery stenosis on transplanted kidney.

Renal artery stenosis is one of the most important complications in the natural history of kidney transplantation. Particular care has to be taken in the use of angiography techniques because of the invasiveness and of the potential toxicity of radiopaque contrast material, even in the less invasive radiological tests, like endovenous sequential angiourography with image subtraction (SAU) and digital subtraction angiography (DSA). Fifty-one patients have been examined with echo-Doppler velocimetry (EDV) and also with SAU in order to verify the previous status of the artery. EDV exhibits a 100% sensitivity: all SAU detected stenosis have been formerly identified via EDV. The non-invasiveness and possibility of early repetition allows an early diagnosis capability for all transplanted patients. In this way, a surgical intervention may quite often be prevented by a precocious use of endoluminal angioplasty.

Adult↗
PubMed1985

S-100 protein-induced changes in the physical state of synaptosomal particulate fractions as monitored by spin labels.

This report documents changes in the physical state of synaptosomal particulate fractions (SYN) upon binding of S-100 protein, as monitored by spin labels. Studies were conducted on SYN labeled with either 5-doxylstearic acid or 16-doxylstearic acid, which probe the polar region and the hydrophobic core of the lipid bilayer, respectively. S-100 perturbs to some extent both the polar surface and the hydrophobic core of SYN in a time- and temperature-dependent manner. Ca2+ is essential for S-100 to perturb the membranes. K+ almost completely inhibits the S-100 perturbing effect if present in the incubation medium, but fails to reverse the S-100-induced changes if added after S-100 has interacted with SYN. At room temperature and below, the overall S-100 effect registered after about 30 min of association of the protein with SYN is an increase in the fluidity of both the surface and the interior of the membranes. Spectra registered at intervals at room temperature indicate that the S-100 perturbing effect on the membrane surface is practically monophasic, consisting of an increase in fluidity, while that on the membrane interior is multiphasic, consisting of a decrease in fluidity during the first 10 min of association, followed by an increase in fluidity during the subsequent 20 min and a return to starting values during the second 30 min of association. Around 37 degrees C, on the contrary, a decrease in fluidity is registered in both regions. The data suggest that S-100 induces a spatial rearrangement of membrane components (proteins) involved in the specific binding and/or partially penetrates into the lipid bilayer.

Animals↗
PubMed1985

Hydatidosis in Sardinia: review and recommendations.

In Sardinia, hydatidosis due to Echinococcus granulosus is endemic and constitutes a current and important problem in the economy and public health. This paper reviews the epidemiological aspects, including the geographical distribution, and the socio-cultural factors involved in the dissemination of hydatidosis. Hospital data indicate that about 200 people undergo surgery for hydatid cysts every year with an average of 8.8 deaths annually. An average of 80% of the sheep are infected, constituting a livestock loss estimated as over 20 billion liras per year. The benefits expected from a hypothetical control programme amount to approximately 32 billion liras against an investment of 17 billion liras in a control programme extending over a period of 10 years. The eradication campaign should result in a gradual reduction of infection rate from 80% to 10% in sheep, from 30% to 3-5% in dogs and in a reduction of human morbidity from 200 to 15 cases, equal to a prevalence rate of 1 per 100,000 inhabitants.

Animals↗