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Biomedical subjects

G Ferretti

Publications and source records attributed to G Ferretti.

At least 181 records · Page 10Linked to original sources
PubMed1994

Increased susceptibility to lipid oxidation of low-density lipoproteins and erythrocyte membranes from diabetic patients.

The aim of the present study was to determine if low-density lipoproteins (LDLs) and red blood cell (RBC) membranes from diabetic patients present an increased susceptibility to lipoperoxidation, which might be related to the increased incidence of atherosclerosis in diabetes. LDLs and RBC membranes were isolated from 11 insulin-dependent (IDDM) and 18 non-insulin-dependent diabetic (NIDDM) patients and exposed to a peroxidative stress by incubation with phenylhydrazine. The susceptibility to peroxidation was determined by measuring the production of thiobarbituric acid-reactive substances (TBARS) after the incubation. The following parameters were also evaluated: plasma glucose, triglycerides (TG), phospholipids (PL), total and high-density lipoprotein (HDL) cholesterol, apolipoprotein (apo) A-I, apo B, hemoglobin A1c (HbA1c), LDL PL and cholesterol, LDL fatty acid composition, and RBC membrane PL and cholesterol. Although they were apparently normolipidemic, diabetic patients showed an increased susceptibility to peroxidation in LDLs and erythrocyte membranes as compared with control subjects. The amount of arachidonic acid in LDLs and the PL concentration of RBC membranes from diabetic patients were significantly higher than in normal subjects. The increased lipoperoxidability of both RBC membranes and LDLs might play a central role in the pathogenesis of the vascular complications of diabetes mellitus.

Adult↗
PubMed1994

Ventilatory responses to hypercapnia and hypoxia in elite breath-hold divers.

It was recently hypothesized that elite breath-hold divers may display blunted ventilatory responses to hypoxia and/or hypercapnia (Ferretti et al., J. Appl. Physiol. 70: 794-802, 1991). To test this hypothesis, the following measurements were made on three elite breath-hold divers (members of the same family), and on 9 healthy untrained control subjects (C): (1) Steady-state pulmonary ventilation (VE) at rest in the supine posture while breathing room air or normoxic CO2-enriched mixtures. (2) Breath-by-breath VE changes (delta VE), with respect to baseline conditions, after 4 breaths of 100% O2, under the following conditions: normoxia (PIO2 = 146 Torr) at rest (NR); normoxic exercise (60 watt on a bicycle ergometer) (NE); hypoxia (PIO2 = 77 Torr) at rest (HR); hypoxic exercise (HE). The results were as follows: (1) In hypercapnic experiments VE (normalized per unit of body surface area) was significantly lower in the divers than in C (4.32 +/- 0.04 [mean +/- SD]L.min-1.m-2 vs. 5.31 +/- 0.62 at FICO2 = 1.5%; 5.21 +/- 0.17 vs. 7.72 +/- 1.39 at FICO2 = 3%; 8.86 +/- 0.76 vs. 13.14 +/- 2.27 at FICO2 = 5%), as well as than in subjects described by previous authors as being characterized by 'low CO2 sensitivity'. (2) The 100% O2-breathing maneuvers did not induce significant delta VE both in NR and in HR, whereas peak delta VE were -6.73 +/- 1.38 L.min-1 (divers) vs. -5.24 +/- 3.10 (C) in NE, and -17.39 +/- 4.92 (divers) vs. -17.52 +/- 6.32 (C) in HE (no significant differences). It is concluded that the divers, compared to C, had a blunted ventilatory response to hypercapnia, but not to hypoxia. The former may represent an adaptive or genetically inherited phenomenon.

Adaptation, Physiological↗
PubMed1994

Immunoscintigraphy using 111in-labelled F(ab')2 fragments of anti-carcinoembryonic antigen (CEA) monoclonal antibody for staging of non-small cell lung carcinoma.

28 patients with primitive lung cancers were imaged by immunoscintigraphy (IS) with 111indium-labelled F(ab')2 anti-carcinoembryonic antigen (CEA), to assess this technique for mediastinal staging. IS revealed primitive tumours in 21 cases in whom mediastinal extension was assessed. There was concordance between clinical staging and IS confirmed by surgery in 17 cases, and discordance in 4. After surgery, discordance was in favour of IS in 2 cases (1 true positive and 1 true negative) and in favour of clinical staging in 2 (false positive of immunoscintigraphy). Anti-CEA IS could be useful for improving mediastinal staging of lung cancer.

Antibodies, Monoclonal↗
PubMed1994

[The dynamics of pharyngeal structures in obstructive sleep apnea (during spontaneous, continuous positive pressure and BiPAP ventilation)].

Obstructive sleep apnea results from a pharyngeal collapse. Upper airway can be investigated using either static or dynamic methods during wakefulness or when the patient is sleeping. Somnofluoroscopy is one of the dynamic methods allowing a visualization of the upper airway during sleep. A lateral projection of the pharynx is obtained during fluoroscopic examination which allows visualization of the upper airway dimensions and the bone structures (hyoid bone, cervical spine, mandible). Standard polygraphic parameters (EEG, EOG, flow rate, thoracic and abdominal movements) and fluoroscopic image are simultaneously acquired on the same videotape. Using this technique, we have described the typical pattern of events occurring during an episode of apnea: 1-beginning of airway occlusion in the oropharynx with anterior or posterior hooking of the soft palate, 2-suction on the uvula downwards and complete occlusion of the oropharynx with further extension to the hypopharynx, 3-active movements of the cervical spine and hyoid bone as if the patient is choking, 4-overcoming of the occlusion usually accompanied by opening of the jaw and occurring either as a sudden event throughout the length of the pharyngeal airway or as a progressive reopening from the hypopharynx. In a recent study, we have investigated upper airway dynamics when a continuous positive pressure with one level (CPAP) or two levels of pressure (BiPAP) was applied. When using CPAP with pressure below the optimal pressure, uvula movements were the first changes we observed, preceding the pharyngeal collapse. Lowering the expiratory pressure alone lead to a significant reduction in pharyngeal dimensions starting at expiration and extending also to inspiration when the expiratory pressure is further reduced. Using BiPAP may lead to upper airway instability. The frequency and the variability of this phenomenon need further studies to be established.

Fluoroscopy↗
PubMed1994

Plasma membrane order parameter in periportal and perivenular hepatocytes isolated from ethanol-treated rats.

Hepatic ethanol (EtOH) metabolism has been assumed to involve hepatocytes differently, according to their location in the hepatic acinus. This study's aim was to gain information on plasma membrane (PM) order parameter in periportal (PP) and perivenular (PV) hepatocyte-enriched fractions isolated by a digitonin-collagenase perfusion technique from rats pair-fed for 6-8 wk liquid diets containing either EtOH or isocaloric carbohydrates. Fluorescence polarization (P) studies have been performed to measure PM order parameter of PP and PV hepatocytes cultured for 2-6 h on glass cover slips and labeled with 1-[4-(trimethylamino)phenyl]-6-phenylhexa-1,3,5-triene (TMA-DPH), a specific probe for PM of living cells. Fluorescence polarization and microscopy indicated that TMA-DPH is a suitable probe to study PM order parameter in subconfluent rat hepatocyte monolayers where it labeled, after a rapid incorporation, PM of cells. In pair-fed control rats, PM order parameter was lower in PP hepatocytes than in PV cells (P = 0.366 +/- 0.013 vs. 0.381 +/- 0.021, respectively, P < 0.02; n = 7). In EtOH-treated rats, these zonal differences tended to disappear (P = 0.419 +/- 0.012 in PP cells vs. 0.417 +/- 0.007 in PV cells; n = 7). In addition, the order parameter was significantly higher either in PP or PV hepatocytes compared with pair-fed control animals (P < 0.002 and 0.003, respectively). A 30-min culture of cells in the presence of 40-200 mM EtOH significantly decreased the PM order parameter of hepatocytes isolated from pair-fed control rats with respect to EtOH-treated animals both in PP and PV cells (P < 0.01 and 0.02, respectively; n = 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Reduced Na(+)-K(+)-ATPase activity and plasma lysophosphatidylcholine concentrations in diabetic patients.

A fraction from normal human plasma inhibiting Na(+)-K(+)-ATPase has been recently identified as lysophosphatidylcholine (LPC). The aim of this study was to investigate the existence of a relationship between the activity of the cellular membrane Na(+)-K(+)-ATPase and plasma LPC in human diabetes. We studied 10 patients with insulin-dependent-diabetes mellitus (IDDM), 14 patients with non-insulin-dependent diabetes mellitus (NIDDM), and 10 sex- and age-matched control subjects. Plasma LPC concentrations were increased in both IDDM and NIDDM patients compared with control subjects. Na(+)-K(+)-ATPase activity was reduced in both groups of patients in erythrocyte and platelet membranes. There was a significant correlation between the concentrations of plasma LPC and Na(+)-K(+)-ATPase activity in both erythrocyte and platelet membranes (P < 0.01). To investigate the effect of LPC on the enzyme, Na(+)-K(+)-ATPase activity was determined in erythrocyte membranes obtained from six healthy subjects after in vitro incubation with increasing concentrations of LPC (1-10 microM). Enzymatic activity was significantly reduced by in vitro LPC at a concentration of 2.5 microM, with a further decrease at 5 microM. These data suggest that the decrease in Na(+)-K(+)-ATPase activity in diabetes might be due to increased LPC concentrations.

Adult↗
PubMed1994

Abnormalities of plasma lipoprotein composition and fluidity in psoriasis.

We have studied the lipoprotein chemical composition and fluidity, using the fluorescence polarization of the probe 1,6-diphenyl-1,3,5-hexatriene (DPH) in two age- and sex-matched groups of subjects (14 healthy normolipidemic children and 15 psoriatic children). The compositional study has shown a significant increase of the percentage content in triacylglycerol and a significant decrease of the apo-protein content in all lipoprotein fractions of psoriatic children compared to the controls. A significant increase of the percentage content in total cholesterol and of the cholesterol/protein ratio has also been observed in low-density lipoproteins (LDL) and in high-density lipoproteins (HDL) of psoriatic children. The compositional changes were associated with alterations of fluidity in LDL and HDL of psoriatic patients. The modifications of lipoprotein composition and fluidity observed in psoriatic patients could be of physiopathological and clinical relevance in relation to the pathogenesis of the disease.

Apolipoproteins↗
PubMed1994

Susceptibility to in vitro lipid peroxidation of low density lipoproteins and erythrocyte membranes from liver cirrhotic patients.

The aim of the present study was to investigate the susceptibility of low density lipoprotein (LDL) and red blood cell membranes (RCM) from liver cirrhotic patients and control subjects, to the peroxidative stress, induced in vitro by phenylhydrazine. The susceptibility to peroxidation was determined by measuring the formation of the thiobarbituric acid reactive substances (TBARS) after incubation with phenylhydrazine. Moreover the levels of cholesterol (C) and phospholipid (PL) were evaluated in plasma and isolated LDL and RCM. A significant decrease in plasma C, LDL-C and RCM-C content (p < 0.001, p < 0.01 and p < 0.05 respectively) and RCM-PL content (p < 0.01) were found in cirrhotic patients compared to controls. The lower susceptibility to in vitro peroxidation was shown by the TBARS levels significantly lower in LDL and RCM from cirrhotic patients with respect to controls (p < 0.0001 for both of them). Moreover significant positive correlations were found between TBARS-LDL and LDL-C or LDL-PL (r = +0.72, p < 0.0001; r = +0.58, p < 0.001) and between TBARS-RCM and RCM-C (r = +0.35, p < 0.05) or RCM-PL (r = 0.37, p < 0.05) from combined patients and controls. Our data seem to ascribe the lower in vitro peroxidability to the lower levels of plasma lipids.

Adult↗
PubMed1994

[The prevention of disorders due to iodine deficiency: the experience of neuropsychological screening].

In this research we investigated some neuropsychological parameters in school-age children living in two areas in which mild iodine deficiency has been found in the past. In Study 1 no significant difference was found in cognitive (WISC-R Block Design test), visuo-motor (WISC-R Coding test modified) and fine distal movements tasks. On the other hand in a Simple Reaction Time task children living in iodine deficient area were significantly slower than controls. In Study 2 the same results were obtained in the group of children born before an extensive iodine prophylaxis program, but not in younger children born later. Our data show that exposure to mild iodine deficiency in fetal/neonatal life does not affect general cognitive performance but slows the speed of motor responses, which may be due to an impairment concerning neural transmission mechanisms.

Child↗
PubMed1994

[Diagnosis of broncholithiasis. Role of high resolution tomodensitometry].

PURPOSE: to evaluate high resolution computed tomography (HRCT) in the diagnosis of broncholithiasis. PATIENTS AND METHODS: 10 patients with broncholithiasis underwent chest X ray, fiberoptic bronchoscopy (FOB), CT and HRCT. RESULTS: in 9 cases, chest X rays were abnormal but the diagnosis of broncholithiasis can't never be affirmed. In 9 cases, FOB was abnormal: broncholith were identified in only 2 cases; the other diagnosis were tumor like stenosis (n = 3), inflammatory stenosis (n = 3), extrinsic compression (n = 1). On conventional CT scan, broncholithiasis was suspected in 8 patients but because of volume averaging the relationship between calcified lymph nodes and bronchial tree was difficult to determine exactly. Only HRCT sections, sometimes tilted in the axis of the middle lobar bronchus, can affirm the endobronchial or peribronchial location of calcified lymph nodes in all patients. CONCLUSION: conventional CT scan can suggest the presence of broncholithiasis but HRCT sections are need to affirm the diagnosis.

Adult↗
PubMed1994

Effect of desialylation on low density lipoproteins: comparative study before and after oxidative stress.

Aim of our study was to investigate the effect of the desialylation induced by neuraminidase treatment on low density lipoprotein susceptibility to peroxidative stress induced by incubation with copper ions. Our results show that peroxidative stress induces the formation of aggregates that was not observed in desialylated low density lipoproteins. An increase in thiobarbituric reactive substances and a decrease in polyunsaturated fatty acids content have been shown in oxidized LDL. These modifications were less pronounced in oxidized low density lipoproteins previously treated by neuraminidase. The present data suggest a lower susceptibility to peroxidative stress in previously desialylated low density lipoproteins.

Apolipoproteins B↗
PubMed1994

Lipoprotein peroxidation in adult psoriatic patients.

Psoriasis, a chronic inflammatory skin disease characterized by an aberration of lipid metabolism, has been associated with an increased risk for atherosclerosis. Since oxidatively modified lipoproteins are involved in the pathogenesis of atherosclerosis, we investigated the lipid composition and in vitro induced peroxidation of very low density lipoproteins (VLDL) and low density lipoproteins (LDL) from psoriatic patients. 11 male adult psoriatics and 16 male age-matched healthy subjects were studied. Lipid peroxidation of VLDL and LDL was performed by incubation with CuSO4 for 24 h at 37 degrees C. The compositional analysis showed a significant increase in triglycerides and phospholipids, both in VLDL (p < 0.05) and in LDL (p < 0.001) from psoriatic patients, compared with controls. Moreover a significant increase in total cholesterol (TC) (p < 0.01) and apoprotein (P) (p < 0.05) was found in LDL from psoriatics. The levels of thiobarbituric acid reactive substances (TBARS), as a measurement of lipid peroxidation, were significantly higher in Ox-VLDL and in Ox-LDL from psoriatics (p < 0.01) than the corresponding values in controls. Moreover, basal values of TBARS were significantly higher in VLDL and LDL from psoriatic patients than those from controls. In conclusion, the lipoprotein compositional changes associated with the modifications of TBARS before and after Cu2+ treatment of lipoproteins may suggest an increased risk for atherosclerosis in adult psoriatic patients.

Arteriosclerosis↗
PubMed1993

Membrane heterogeneity in isolated rat hepatocytes and liver plasma membrane subfractions: a comparative study using DPH and its cationic derivative TMA-DPH.

The fluorescence decay of 1,6-diphenyl-1,3,5-hexatriene (DPH) and of 1-(4-trimethylammonium-phenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) has been studied in hepatocytes isolated from rat liver and in isolated plasma membrane subfractions (cLPM, canalicular membranes and bLPM, basolateral membranes) using frequency domain fluorometry. The decay has been analyzed either by using a model of discrete exponential components or a model that assumes a continuous distribution of lifetime values in order to study different aspects of membrane heterogeneity. The results obtained by the two analyses are practically superimposable but the distributional approach allows an evaluation of membrane heterogeneity through the width of the distribution that has shown particularly significant differences when freshly hepatocytes are compared with in vitro aged hepatocytes. Moreover, the comparison of the distributional analysis of the two probes has shown in cLPM a tendency to higher values of the main lifetime component and a narrower distribution width with respect to bLPM. These results indicate changes of membrane domain organization that have been discussed in relation with the specific lipid composition that characterizes the two membrane subfractions. Our results indicate that frequency domain fluorometry may be used to study membrane heterogeneity in intact cells and isolated membranes.

Animals↗