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Biomedical subjects

G Ferretti

Publications and source records attributed to G Ferretti.

At least 217 records · Page 12Linked to original sources
PubMed1992

Plasma lipid changes in psoriatic children.

Plasma lipid, lipoprotein and apoprotein concentrations were determined in psoriatic children and in healthy controls. The plasma total cholesterol (TC) was higher than in controls (p = 0.03). The higher cholesterol levels were explained by an almost significant increase in cholesterol associated with high-density lipoproteins and by the tendency towards higher values of cholesterol associated with low-density lipoproteins and very-low-density lipoproteins. No significant changes of plasma triglycerides were observed. Levels of apoproteins (apo) AI and apo B were not significantly different in psoriatic children; however, the levels of apo B were correlated differently with plasma TC in psoriatic children, and the ratio TC/apo B was significantly increased in patients with respect to the controls, suggesting some differences of plasma lipoprotein lipid/apoprotein relationship in psoriasis.

Adolescent↗
PubMed1992

Gas exchange kinetics in heart transplant recipients.

Submaximal and/or peak levels of oxygen consumption (VO2), pulmonary ventilation (VE), heart rate (HR), stroke volume of heart (SV), cardiac output (Q), muscle blood flow (qm), as well as the kinetics of readjustment of gas exchange, Q and qm (t1/2 VO2on-, t1/2 Qon-, t1/2 qmon-) were determined in 44 heart transplant recipients (HTRs) and in a group of age-, sex-, and physical activity-matched control subjects (CTL) when carrying out rectangular loads (25 to 125 W) on a bicycle ergometer. The increase of SV occurring at work onset appears to compensate in HTRs for the sluggish readjustment of HR so that the rate of readjustment of Q is kept within normal limits. As a consequence, qm, t1/2 q mon-, and t1/2 VO2on- appear to be similar or only moderately delayed in HTRs compared with CTLs. It is concluded that in HTRs, because of constrained maximum HR, only work loads up to 60% of the VO2max of CTLs may be attained; also, owing to the fast readjustment of Q, up to work loads of 75 to 100 W, the rest to work transition phase is not impaired.

Electrocardiography↗
PubMed1992

Lower susceptibility of low density lipoprotein to in vitro oxidation in diabetic patients.

The susceptibility to peroxidative stress of low density lipoprotein (LDL), induced by incubation with CuSO4, has been studied in eleven diabetic patients and eleven control subjects. Our results suggest that oxidized LDL (OX-LDL) of diabetic patients have a significant higher reactivity to 2,4,6-trinitrobenzene sulfonic acid (TNBS) than controls, that indicates a lower susceptibility of LDL to oxidative stress. Furthermore using the fluorescence polarization (Pf) of 1,6-diphenyl-1,3,5-hexatriene (DPH) and its phosphatidylcholine derivative (DPH-PC) we have shown that peroxidation induces a decrease of fluidity in OX-LDL of controls and diabetic patients, both at the lipoprotein surface, where is localized DPH-PC and at the interface between lipoprotein surface and core which is probed by DPH.

Adult↗
PubMed1992

[How can the extension of lung cancer to the osteo-muscular wall of the diaphragm, the pleura and the apex be assessed radiologically?].

The merits of evaluating the parietal extension of lung cancers is emphasized by the new TNM classification. CT and MRI have added to the conventional radiological techniques. The authors successively analyze the contribution of these techniques to the assessment of extension of lung cancers to the wall, including the costal and phrenic compartments, to the pleura and to the apex. Lung radiographs show obvious lesions, such as extensive costal lysis and major pleural extensions. Computed tomography has better sensitivity and specificity than lung radiographs to establish pleuroparietal involvement; it is best performed in the inclined plane of the ribs and in the high-resolution mode. The presence of costal lysis means parietal involvement, while the integrity of the pleura can be established if the lesion remains at a distance from the wall. The persistence of an extrapleural fatty rim between the tumor and the wall allows ruling out parietal extension. MRI provides accurate details in case of doubtful CT findings for the extension to the costovertebral groove, to the intervertebral foramina, to the peridural space and to the diaphragm. Its major asset is to assess the vertebral, vascular and nervous extension of cancers of the apex pulmonis.

Carcinoma, Non-Small-Cell Lung↗
PubMed1992

Evaluation of the upper airway in sleep apnea syndrome.

The upper airway is the final common site for abnormalities in respiratory control and neuromuscular function leading to sleep apnea. This review summarizes the information that pharyngeal assessment provides for understanding upper airway pathophysiology and selecting treatment. The applications and limitations of both static and dynamic techniques are examined in awake and sleeping patients. The effects of posture on the upper airway and the usefulness for predicting treatment efficiency are examined.

Airway Obstruction↗
PubMed1992

[Diffuse infiltrative lung diseases: histological support of elementary lesions observed on tomodensitometry].

High resolution computed tomography (TDM-HR) is now the technique of choice in the diagnosis and management of diffuse infiltrative lung disease (PID). After a brief review of the technique the authors describe the normal appearance; anatomical observations and the in vivo findings have shown that TDM-HR allow for the exploration of details of structure down to the second pulmonary lobule. Thus, through the alterations that are transmitted in the lobular area, and from its contents and its limits, PID has led to the elaboration of a new semeiology. The authors review the basic computed tomographic images and correlate these in each case with the histological evidence. The spatial distribution and the time sequence of the elementary images are the two other terms in the diagnostic equation of PID. The spatial distribution of several elementary images presents in TDM-HR a superior aetiological pointer to that which is furnished by thoracic radiographs; and the time sequence may furnish a useful indication as to the progress of the treated disease. Sarcoidosis, histiocytosis X, idiopathic interstitial fibrosis and lymphangitis carcinomatosis would serve as examples. Nevertheless, the authors point out that it would be dangerous during the period of evaluation to prematurely extend to all cases of PID conclusions which are only possible to make at present in a restricted number of disorders.

Histiocytosis, Langerhans-Cell↗
PubMed1992

Mild iodine deficiency in fetal/neonatal life and neuropsychological performances.

The effects of mild/moderate iodine deficiency during the fetal/neonatal life on neuropsychological performances are still poorly defined. In this research we analyzed some parameters of cognitive performance with sensitive psychometric tests in children living in an area with moderate iodine deficiency. Each subject was submitted to the following neuropsychological tests: 1) a reaction time (RT) session, 2) the block design subtest of the WISC-R, 3) the coding subtest of the WISC-R. No significant difference was found between children with mild iodine deficiency and controls, for block design and coding tests. On the other hand controls had significantly faster RTs. Our data show that exposure to mild iodine deficiency in fetal/neonatal life does not affect general cognitive performance but influences the velocity of motor response to visual stimuli, which may be due to an alteration of the efficiency of the information processing mechanism.

Child↗
PubMed1992

Interaction of a phosphatidylcholine derivative of 1,6-diphenyl-1,3,5-hexatriene (DPH-PC) with lymphocytes.

In this study we have demonstrated a transfer of a phosphatidylcholine derivative of 1,6-diphenyl-1,3,5-hexatriene (DPH-PC) from self-quenched lipid vesicles to intact lymphocytes. Membrane labeling was followed measuring the time dependent reexpression of fluorescence. The results of fluorescence quenching by 2,4,6-trinitrobenzene sulfonate and the decrease of fluorescence polarization values during incubation at 37 degrees C, suggest that the probe could remain localized at level of the plasma membrane until 20-30 minutes. DPH-PC is identical to the natural phospholipid with respect to head group structure and polarity therefore we suggest that under appropriate experimental conditions, it could represent an useful tool to study the physico-chemical properties of specific phospholipid domains in the plasma membrane of intact cells.

Animals↗
PubMed1991

Platelet release products modulate some aspects of polymorphonuclear leukocyte activation.

The aim of this research was to evaluate in vitro interactions between platelets and polymorphonuclear leukocytes. The effects of supernatant from thrombin-activated platelets and two platelet release products (adenosine triphosphate and beta-thromboglobulin) were tested on the following features of polymorphonuclear leukocytes activation: opsonized zymosan and phorbol myristate acetate stimulated chemiluminescence, release of membrane bound calcium, NADPH-oxidase activity, and membrane fluidity (fluorescent polarization). The results showed that the addition of platelet supernatant to polymorphonuclear leukocytes induces a significant activation of cells. On the other hand, after three hours of preincubation of polymorphonuclear leukocytes with platelet supernatant, a decreased response of polymorphonuclear leukocytes to stimulation with phorbol myristate acetate, a significant decrease in NADPH-oxidase activity, and a lowered membrane fluidity were observed. Adenosine triphosphate modulated only opsonized zymosan stimulated chemiluminescence, with and without preincubation with polymorphonuclear leukocytes. Beta-thromboglobulin caused a decrease of the chemiluminescent response of polymorphonuclear leukocytes, using both agonists, with and without preincubation with polymorphonuclear leukocytes. Moreover beta-thromboglobulin only caused a decrease of the polymorphonuclear leukocytes membrane fluidity without preincubation with the cells. These results support the thesis that platelets have a "time-related" modulating activity on polymorphonuclear leukocytes.

Adenosine Triphosphate↗
PubMed1991

Energetics of locomotion in African pygmies.

The energy cost of walking (Cw) and running (Cr), and the maximal O2 consumption (VO2max) were determined in a field study on 17 Pygmies (age 24 years, SD 6; height 160 cm, SD 5; body mass 57.2 kg, SD 4.8) living in the region of Bipindi, Cameroon. The Cw varied from 112 ml.kg-1.km-1, SD 25 [velocity (v), 4 km.h-1] to 143 ml.kg-1.km-1, SD 16 (v, 7 km.h-1). Optimal walking v was 5 km.h-1. The Cr was 156 ml.kg-1.km-1, SD 14 (v, 10 km.h-1) and was constant in the 8-11 km.h-1 speed range. The VO2max was 33.7 ml.kg-1.min-1, i.e. lower than in other African populations of the same age. The Cr and Cw were lower than in taller Caucasian endurance runners. These findings, which challenge the theory of physical similarity as applied to animal locomotion, may depend either on the mechanics of locomotion which in Pygmies may be different from that observed in Caucasians, or on a greater mechanical efficiency in Pygmies than in Caucasians. The low Cr values observed enable Pygmies to reach higher running speeds than would be expected on the basis of their VO2max.

Africa↗
PubMed1991

Evaluation of L-thyroxine replacement therapy in children with congenital hypothyroidism.

The outcome of L-thyroxine (L-T4) replacement therapy in children with congenital hypothyroidism (CH) remains to be completely evaluated. In this paper the overall pattern of response to L-T4 replacement therapy was studied in a group of 19 children with CH diagnosed by neonatal screening (10 with hypoplastic/aplastic thyroid disease, group H/A; 9 with gland ectopy, group E) who were followed-up for 60 +/- 27 months (mean +/- SD). With 1 exception serum T4 at diagnosis was greater than 2 micrograms/dl in children of group E and less than 2 micrograms/dl in those of group H/A. The initial dose of L-T4 (8-10 micrograms/kg BW/day) was modified in relation to age and weight in order to maintain serum TSH less than or equal to 5 microU/ml and FT3 in the normal range. A general inverse correlation between serum TSH and FT4 or FT3 concentrations was found, and the mean levels of serum FT4 and FT3 were significantly higher according to the following order of TSH results: low TSH (0-0.5 microU/ml) greater than normal (greater than 0.5-5 microU/ml) greater than elevated TSH (greater than 5 microU/ml). TSH levels less than or equal to 5 microU/ml were associated with FT4 values in the upper half of the normal range (54% of observations) or even higher (46%). Elevation of serum FT4 alone with FT3 values in the normal range did not result in clinical thyrotoxicosis, alteration of growth or premature craniosynostosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1991

Erythrocyte membrane fluidity and changes in plasma lipid composition: a possible relationship in childhood obesity.

We have studied plasma lipid patterns and erythrocyte membrane fluidity in 60 obese children and 20 normal children. Plasma levels of total cholesterol and associated low-density lipoproteins were significantly increased in 20 obese patients with respect to controls. A significant decrease in membrane fluidity, measured as an increase in the fluorescence polarization value of the probe 1,6-diphenyl-1,3,5-hexatriene, associated with an increase in the cholesterol/protein ratio has been shown in obese patients. The study of the correlation between erythrocyte membrane fluidity and plasma cholesterol has indicated that significant changes in fluidity and membrane lipid composition also occur in erythrocytes of obese patients with normal plasma lipid levels. These findings confirm that the erythrocyte membrane responds very early to modifications of plasma lipoproteins and suggest that in childhood obesity a modified transfer of cholesterol from plasma to erythrocyte membrane may take place.

Adolescent↗
PubMed1991

Alveolar gas composition and exchange during deep breath-hold diving and dry breath holds in elite divers.

End tidal O2 and CO2 (PETCO2) pressures, expired volume, blood lactate concentration ([Lab]), and arterial blood O2 saturation [dry breath holds (BHs) only] were assessed in three elite breath-hold divers (ED) before and after deep dives and BH and in nine control subjects (C; BH only). After the dives (depth 40-70 m, duration 88-151 s), end-tidal O2 pressure decreased from approximately 140 Torr to a minimum of 30.6 Torr, PETCO2 increased from approximately 25 Torr to a maximum of 47.0 Torr, and expired volume (BTPS) ranged from 1.32 to 2.86 liters. Pulmonary O2 exchange was 455-1,006 ml. CO2 output approached zero. [Lab] increased from approximately 1.2 mM to at most 6.46 mM. Estimated power output during dives was 513-929 ml O2/min, i.e. approximately 20-30% of maximal O2 consumption. During BH, alveolar PO2 decreased from approximately 130 to less than 30 Torr in ED and from 125 to 45 Torr in C. PETCO2 increased from approximately 30 to approximately 50 Torr in both ED and C. Contrary to C, pulmonary O2 exchange in ED was less than resting O2 consumption, whereas CO2 output approached zero in both groups. [Lab] was unchanged. Arterial blood O2 saturation decreased more in ED than in C. ED are characterized by increased anaerobic metabolism likely due to the existence of a diving reflex.

Adult↗
PubMed1991

[Role and limits of x-ray computed tomography and magnetic resonance imaging in acquired diseases of the aorta].

The introduction of computed tomography (CT) and the more recent magnetic resonance imaging (MRI) has radically changed the means of investigating acquired aortic disease by association the visualisation of the blood flow, previously available with angiography, with that of the aortic wall and the surrounding structures of this vessel. The popularity of CT scanning, being nearly non-invasive though dependent on ionising radiation and requiring the injection of contrast, and its diagnostic performance have raised it to the status of a primary investigation for diagnosing aortic aneurysm, especially abdominal, of aortic dissection, its acute complications and postoperative follow-up. However, CT scanning remains unsatisfactory for the examination of collateral and bypass vessels issuing from the aorta and for detailed analysis of aortic trauma and aortitis. MRI, though providing significant diagnostic advantages by the 3 dimensional visualisation of the aorta, the presence of spontaneous contrast between the lumen and vessel wall and cine MRI, is still relatively little used because of the small number of installations dealing with this indication in France. Despite the limitation, this totally non-invasive and non-irradiating investigation is progressively extending its use for the diagnosis of certain subacute or chronic aortic diseases. MRI is the best non-invasive investigation for the diagnosis of thoracic aortic aneurysms, chronic or subacute aortic dissection and for repeated postoperative follow-up after thoracic aortic surgery. Technological advances of this new imaging method and the multiplication of the number of installations suggest that the field of application of MRI for disease of the aorta will steadily increase in the future.

Aortic Dissection↗
PubMed1991

Beta-thromboglobulin and polymorphonuclear leukocytes activation. (Effects on chemiluminescence, release of membrane bound calcium, NADPH-oxidase activity and membrane fluidity).

The aim of this paper was to evaluate the "in vitro" interaction between beta-thromboglobulin, one specific platelet release product and polymorphonuclear leukocytes. The effects of beta-thromboglobulin were tested on the following features of polymorphonuclear leukocytes activation: opsonized zymosan and phorbol myristate acetate stimulated chemiluminescence, release of membrane bound calcium, NADPH-oxidase activity, and membrane fluidity. Beta-thromboglobulin caused a decrease of the chemiluminescent response of polymorphonuclear leukocytes, using both agonists, with and without preincubation with polymorphonuclear leukocytes. We observed that beta-thromboglobulin caused a decrease also in the activity of NADPH-oxidase but not in the release of membrane bound calcium. Moreover beta-thromboglobulin caused a decrease of the polymorphonuclear leukocytes membrane fluidity. Our results suggest that the beta-thromboglobulin could play a role in the reciprocal interactions between platelets and polymorphonuclear leukocytes.

Blood Platelets↗
PubMed1991

Electrocardiogram during deep breath-hold dives by elite divers.

A portable ECG recorder was used during breath-hold dives at sea by 3 elite divers to 65 and 45 m. ECG was also recorded during nonimmersed maximal breath holds in the divers and 8 control subjects. Heart rate in the dives decreased rapidly to 20-24 beats.min(-1). During the surface experiments in the divers, bradycardia was much slower in onset, reaching 28-36 beats.min(-1) at the end of the breath holds. The divers showed a more consistent bradycardial response than the controls. The difference in temporal pattern of bradycardia, in the dives and in the breath holds by the divers, may have been due to face immersion in cold water, chest compression, and/or redistribution of blood into the chest with concomitant stimulation of cardiac and other mechanoreceptors. Arrhythmias, mostly supraventricular and ventricular premature complexes, were observed coincidently with the lowest heart rates, presumably reflecting a high vagal tone. In addition, cardiac distention at depth might have made the heart more prone to arrhythmias, while in the surface breath holds hypoxia might have accounted for a similar effect.

Adult↗
PubMed1990

On maximal oxygen consumption in hypoxic humans.

The present paper discusses the factors affecting maximal O2 consumption (VO2max) in hypoxia (4300 m above sea level) along the following lines: 1) In acute hypoxia, the fractional limitation to VO2max imposed by circulatory O2 transport (FQ') is 50%, instead of 70% as in normoxia. This is due to the increase in the blood O2 transport coefficient (beta b) as PO2 decreases, as a consequence of the sigmoidal shape of the O2 dissociation curve of hemoglobin. The remaining 50% is assumed to be equally partitioned between tissue O2 transfer (Ft') and mitochondria O2 utilization (Fm'). 2) In chronic hypoxia, FQ' = 0.45, Ft' = 0.20 and Fm' = 0.35, as a consequence of reduced muscle fiber size and muscle mitochondrial density following acclimatization. 3) The relationship between VO2max and PIO2 in both acute and chronic hypoxia reflects the O2 dissociation curve. 4) Acclimatization to chronic hypoxia does not have the function of preserving VO2max.

Acute Disease↗