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Biomedical subjects

M Antonelli

Publications and source records attributed to M Antonelli.

At least 91 records · Page 5Linked to original sources
PubMed1994

Food allergy in cystic fibrosis.

Food allergy was investigated in 20 children with cystic fibrosis (CF), who still suffered from diarrhea and failed to thrive, in spite of adequate diet and enzyme treatment (group A). The study also included two age-matched control groups, comprising 10 CF children without intestinal symptoms and/or failure to thrive (group B), and 20 healthy children (group C). Skin tests were positive and total IgE higher than the mean + 2SD respectively in 14/20 and 11/20 patients of group A, in 3/10 and 2/10 patients in group B and in none in group C. The specific IgE were present in 6/14 children in group A whose skin tests were positive and in none in group B. There was no significant difference between group A and group B (p > 0.05). The levels of specific antibodies IgG, IgA and IgM were overall higher than the mean + 2SD of the normal in 18/20 in group A, in 6/10 in group B and in none in group C. The measurement by ELISA of specific antibodies for cow milk and egg proteins showed a statistically significant difference for casein, beta-lactoglobulin and ovalbumin between the IgG (p < 0.05) and IgA (p < 0.001) levels in group A and the other groups (B and C). Symptoms improved in 90% of CF patients (group A) when the implicated foods were eliminated from the diet and in 78% the oral provocation test resulted positive. The occurrence of food allergy must be considered in CF patients who do not improve with the conventional treatment. In these patients immunological investigations, in particular the measurement of IgG, IgA and IgM specific antibodies, are useful for diagnosis and in selecting an appropriate diet leading to an improvement in nutritional status.

Adolescent↗
PubMed1994

Leukotrienes and alpha tumor necrosis factor levels in the bronchoalveolar lavage fluid of patient at risk for the adult respiratory distress syndrome.

OBJECTIVE: To examine bronchoalveolar lavage (BAL) fluid of patients at risk for Adult Respiratory Distress Syndrome in the attempt to provide evidence of an increased local production of Leukotrienes (LTS) and Tumor Necrosis Factor (TNF). DESIGN: Prospective, comparative, clinical study. SETTING: ICU in a university hospital. PATIENTS: 14 patients at risk for ARDS and 10 control patients undergoing mechanical ventilation, were studied. INTERVENTION: BAL was performed in each patient at the time admission to the ICU (T0), and after 48 hours (T1). RESULTS: Our controls never showed levels of TNF > 10 pg/ml and their LTS amounts were always below the detection limit. All patients at risk had levels of TNF ranging between 22 and 130 pg/ml, but no difference was noticed between patients who developed ARDS and those who did not, between survivors and non survivors, and between septic and non septic patients. LTD4 and LTB4 (ranging between 30 to 1365 pg/ml) were detected only in six of the 14 patients. Among these 6 patients, 4 developed ARDS. In these patients we could correlate LTB4 with TNF levels and the number of neutrophils recovered from the BAL fluid. CONCLUSION: In our patients leukotrienes and TNF in the BAL fluid correlate well with the acute inflammatory phase of ARDS, as reflected by the increase number of leukocytes in the fluid retrieved, but they do not appear to be clearly predictive index for the syndrome.

Adult↗
PubMed1994

[Evaluation of exocrine pancreatic insufficiency in cirrhotic patients,using the fecal chymotrypsin test].

In spite of having been the object of a number of studies, the association of morphologic and functional alterations of the pancreas with liver cirrhosis is as yet controversial. Therefore, the authors have studied exocrine pancreatic function in 40 patients: 8 with alcoholic cirrhosis, 18 with non-alcoholic cirrhosis, and 14 without evidence of hepatobiliary and pancreatic pathology. Pancreatic function was studied by the fecal chymotrypsin test which is sufficiently sensitive and specific and has been preferred in view of its practicability and non-invasiveness. Analysis of the results showed pathologic values to be significantly more frequent in subjects with alcoholic cirrhosis (50%, p < 0.05) compared to non-alcoholic cirrhotics (11.11%) and to controls (7.2%). These findings go to show that pancreatic exocrine deficit is frequently associated with alcoholic cirrhosis, thus confirming what has already been known about the pathogenetic role of alcohol which is apt to provoke both hepatic and pancreatic damage. Finally, it should be pointed out that pancreatic exocrine deficit is a purely functional alteration without clinical manifestations.

Aged↗
PubMed1993

Propofol induces bronchodilation in mechanically ventilated chronic obstructive pulmonary disease (COPD) patients.

The aim of this study was to evaluate the effects of propofol administration (2 mg.kg-1 i.v.) on the airways resistances and respiratory mechanics of patients affected by COPD exacerbation, requiring mechanical ventilation. Twenty patients required anaesthesia for diagnostic or therapeutic procedures. Fourteen consecutive patients were divided at random into two groups: Group P received propofol and Group C (control) received only Intralipid 10%; an additional group of six patients received i.v. flunitrazepam (0.03 mg.kg-1). Lung mechanics (dynamic and static compliance, peak inspiratory pressure, intrinsic positive and expiratory pressure, minimal and maximal resistances of the respiratory system) were evaluated in basal conditions and 3 and 6 min after propofol, Intralipid or flunitrazepam administration. We did not observe significant variations of the evaluated variables after Intralipid or flunitrazepam (Groups C and F), while in patients who received propofol (Group P), we observed the following modifications: dynamic compliance increased from 2.3 +/- 0.3 to 2.8 +/- 0.4 ml.kPa-1 (P < 0.05), peak inspiratory pressure decreased from 3.3 +/- 0.7 to 2.8 +/- 0.4 kPa (P < 0.05), minimal resistances of the respiratory system (that mainly reflect airways resistances) decreased from 1 +/- 0.2 to 0.7 +/- 0.2 kPa.l-1 x s-1 (P < 0.01). Our results suggest that propofol induces bronchodilation in mechanically ventilated COPD patients, and that this effect is not related specifically to the induction of general anesthesia.

Aged↗
PubMed1993

Effect of intravenous immunoglobulin on opsonic activity and TNF production in patients at high risk for sepsis syndrome.

In a randomized double blind study, we analyzed the efficacy of IVIG in the infectious complications in patients at high risk of developing sepsis syndrome. Two groups of twenty patients were enrolled, one receiving 250 mg/Kg of IVIG on the first and seventh day after admission and the other receiving sterile saline as placebo. Serum samples were drawn before IVIG administration and 24, 48 and 72 hours afterwards. The same schedule was used for patients treated with placebo. Sera pooled from healthy donors served as controls. On all the samples, opsonic and bactericidal activity as well as C3, total IgG and serum TNF content were tested. IVIG did not significantly affect total IgG and C3 content. Similarly, opsonic and bactericidal activity tested against E. coli 06 :K-, E. coli 0111 and SAC I was not modified ranging within HPS values. Furthermore, IVIG administration did not change the TNF level. A lower incidence of bacteremia in IVIG treated patients was observed.

Blood Bactericidal Activity↗
PubMed1992

Xenopus laevis oocyte G alpha subunits mRNAs. Detection and quantitation during oogenesis and early embryogenesis by competitive reverse PCR.

The expression of mRNAs coding for different Xenopus laevis oocyte G alpha subunits was analyzed by the PCR technique. Using the nucleotide sequences of five previously cloned cDNAs for oocyte G alpha subunits [FEBS Lett. 244, 188-192, 1989; FEBS Lett. 268, 27-31, 1990] and the highly sensitive reverse PCR reaction we found that G alpha o, G alpha i-1, G alpha i-3 and G alpha s species are present in oocyte stage VI, G alpha o mRNA being the most abundant transcript. G alpha o mRNA was further quantitated through oogenesis, unfertilized eggs and early embryogenesis stages by a competitive PCR reaction using an 'in vitro' deleted G alpha o mRNA as the internal standard. Using this approach we found that Xenopus G alpha o mRNA levels were constant during oogenesis and unfertilized eggs at a concentration of 3.5 pg of mRNA/stage (5 x 10(5) molecules) and diminish gradually during early embryogenesis, reaching a level of 0.3 pg in the gastrula stage. These findings show that oocyte G alpha o, and perhaps the rest of the alpha subunits, are expressed as maternal mRNAs and could play an important role in signal transduction at the beginning of oocyte cell differentiation.

Animals↗
PubMed1992

Differential stimulation of the GTPase activity of G-proteins by polylysine.

Polylysine, polyornithine and, to a lesser extent, polyarginine were found to stimulate the GTPase activity of the purified recombinant alpha subunit of the human G(i)-3 transducing protein alpha i-3. Optimal stimulation of 4- to 5-fold was obtained with polylysine concentrations between 1 and 20 microM, higher concentrations being inhibitory. Polylysine at similar concentrations stimulated by 50% the GTPase of transducin (GT), the vision transducing protein, but had only a very slight effect on the GTPase of the p21 product of the H-ras protooncogene. The stimulation of the alpha i-3 GTPase caused by polylysine was due to a reduction of the apparent Km for GTP from 3.8 to 1.3 microM. The stimulation by polylysine was observed at free Mg2+ concentrations below 1 microM. These results indicate that polylysine acts in a fashion similar to mastoparan and substance P in mimicking the action of an agonist-bound receptor on G-proteins.

Enzyme Activation↗
PubMed1992

A fibre optics system for the evaluation of airway pressure in mechanically ventilated patients.

OBJECTIVE: The present study was intended to evaluate the "in vivo" endotracheal (ET) tube resistance and respiratory mechanics in mechanically ventilated patients with respiratory failure by using fiber optic catheters. DESIGN: Two fiber optic catheters, consisting of a thin probe with a pressure transducer on the tip, were used. The first was placed at the proximal side of the ET tube and the second was positioned distally beyond the end. A low compliant air-filled catheter connected to a traditional pressure transducer was placed close to the proximal fiber optic device to compare the pressure values obtained with both systems. SETTING: The study was performed in the General Intensive Care Unit of Rome "La Sapienza", University Hospital. PATIENTS AND PARTICIPANTS: Seven patients admitted for the management of acute respiratory failure of different etiologies were included in the protocol. All the patients were intubated and mechanically ventilated for at least 48 h prior to the investigation. MEASUREMENTS AND RESULTS: The endotracheal tube resistance was obtained both by the end-inspiratory occlusion method and measuring pressure proximally and distally to the ET tube. The measurement of respiratory mechanics was obtained proximally and distally to the ET tube. Different flows and tidal volume changes were performed. The results showed that the fiber optic device gives an adequate evaluation of airway pressure and the possibility for an easy detection of obstructions and/or deformations of the ET tube. The area described by inspiratory and expiratory pressure recorded at both sides of the ET tube showed a positive relationship between the surface and flows while no surface changes were shown when the tidal volumes were modified. Thoraco-pulmonary compliance measured proximally and distally to the ET tube gave rise to a small and statistically insignificant difference. CONCLUSION: This study confirms that 48 h after the positioning of ET tubes the airflow resistance is significantly higher than might be expected from the "in vitro" data. The presence of the endotracheal tube can interfere with the evaluation of thoraco-pulmonary mechanics, particularly in dynamic conditions. The fiber optic system represents an interesting and simple tool for the evaluation of ET tube resistance and pulmonary mechanics in patients undergoing mechanical ventilation.

Adult↗
PubMed1992

Early prediction of successful weaning during pressure support ventilation in chronic obstructive pulmonary disease patients.

OBJECTIVE: The aim of this study was to examine variables for early prediction of successful weaning in chronic obstructive pulmonary disease (COPD) patients during pressure support ventilation weaning. DESIGN: Thirteen COPD patients were prospectively studied to compare the respiratory pattern (inspiratory time, expiratory time, total breath cycle duration, tidal volume, respiratory rate, minute ventilation), the respiratory drive (airway occlusion pressure at 0.1 sec, tidal volume/inspiratory time), and blood gases after 30 mins of pressure support weaning. SETTING: The study was performed in the 20-bed General Critical Care Unit of the Rome "La Sapienza" University Hospital. PATIENTS: We evaluated 13 consecutive COPD patients fulfilling the standard weaning criteria (including clinical status, blood gases, forced vital capacity, maximum inspiratory pressure, and spontaneous respiratory rate after a 30-min T-piece trial) in which we compared respiratory pattern, respiratory drive, and blood gases after 30 mins of pressure support weaning. MEASUREMENTS AND MAIN RESULTS: After 30 mins of pressure support ventilation weaning (pressure support level 20 cm H2O), we measured respiratory pattern (airway pressure and airflow tracing), airway occlusion pressure at 0.1 sec (occluding the inspiratory line during expiration with a rubber balloon), tidal volume/inspiratory time, maximal inspiratory pressure, and blood gases. According to the result of the weaning trial, the patients were divided into two groups (not weaned and weaned), and the statistical difference between the evaluated variables was analyzed in weaned and not weaned groups. We did not observe a significant difference in breathing pattern data and arterial blood gases between weaned and not weaned patients. By contrast, airway occlusion pressure at 0.1 sec and maximum inspiratory pressure measured after 30 mins of weaning trial appeared significantly (p less than .001) different in patients in whom the weaning trial succeeded or failed. Considering maximum inspiratory pressure, we could not separate weaned from not weaned patients, while all patients showing values of airway occlusion pressure at 0.1 sec less than 4.5 cm H2O were easily weaned. CONCLUSIONS: This study confirms that conventional weaning criteria are often inadequate in predicting successful weaning of COPD patients, while airway occlusion pressure at 0.1 sec during the first phase of pressure support ventilation weaning can represent a good weaning predictor.

Aged↗
PubMed1991

Gallstones in cystic fibrosis: a critical reappraisal.

Radiolucent gallstones are common in young adults with cystic fibrosis. In the mid-1970s, it was suggested that gallstones are made of cholesterol, but this hypothesis has never been tested. Several recent studies have shown that the detection of cholesterol monohydrate crystals in bile has high sensitivity and specificity for the diagnosis of cholesterol gallstones. We therefore used this approach to study 17 young adults with cystic fibrosis, 10 of whom had radiolucent gallstones. The two groups of patients were comparable in age and gender (all patients but one were male). Duodenal bile was obtained after gallbladder contraction with intravenous cerulein; it was used for lipid and protein chemistry studies and for polarizing microscopy. The latter was performed both in whole bile and in the postultracentrifugation (100,000 g) sediment. Bile cholesterol saturation did not significantly differ between patients with (1.21 +/- 0.28) or without gallstones (0.99 +/- 0.54). Slight cholesterol supersaturation was found in 7 of 10 gallstone and three of seven nongallstone patients. At no time were cholesterol crystals detected in either the group, even after bile ultracentrifugation. Two more cystic fibrosis patients with gallstones died of severe bronchopneumopathy, and small pigment gallstones were obtained at autopsy. At stone analysis, cholesterol content was 44% and 28% of dry weight, respectively. Infrared spectroscopy of stone powder was compatible with the presence of calcium bilirubinate and proteins as major components. We conclude that radiolucent gallstones of cystic fibrosis are not of the conventional cholesterol type.

Adolescent↗
PubMed1991

Effect of Na+, K(+)-ATPase modifiers on high-affinity ouabain binding determined by quantitative autoradiography.

There is growing evidence on the existence of endogenous ouabain-like factors that modulate Na+, K(+)-ATPase activity. In this laboratory, two soluble subfractions (peaks I and II) were previously separated from rat cerebral cortex, which had opposite effects on Na+, K(+)-ATPase activity. Peak I stimulated and peak II inhibited the enzyme (Rodríguez de Lores Arnaiz and Antonelli de Gómez de Lima, Neurochem Res 11:933-947, 1986). The same effects are now reported for K(+)-p-nitrophenyphosphatase activity. Localization of high-affinity ouabain binding in rat brain was done by quantitative autoradiography using a microcomputer digital imaging system. Peak I did not modify, whereas peak II blocked ouabain binding in areas 3-4 of cerebral cortex, dentate gyrus, stria terminalis, thalamic nuclei, and basal ganglia. Similar results were obtained when ouabain binding was determined in rabbit cerebral cortex and by a conventional filtration assay in nerve ending membranes obtained from rat cerebral cortex. These results favour the idea that the factor present in peak II fraction might behave as an ouabain-like substance.

4-Nitrophenylphosphatase↗
PubMed1991

Hyperdense middle cerebral artery CT sign. Comparison with angiography in the acute phase of ischemic supratentorial infarction.

The early CT finding of an hyperdensity of a portion of the middle cerebral artery Hyperdense Middle Cerebral Artery Sign (HMCAS), in patients with supratentorial stroke, is often indicative of an embolic occlusion. Aim of this study was to verify the incidence and reliability of the HMCAS and its possible correlation with early CT findings and with the extent of late brain damage. We studied 36 patients presenting with symptoms of stroke in the MCA territory, by means of CT and angiography performed respectively within 4 and 6 hours. Follow-up CT scans were then obtained after one week and three months from the ischemic event. The HMCAS was present in 50% of our patients and in this group it always correlated positively with the angiographic finding of occlusion. The same group presented a high incidence of early CT hypodensity (88%). Finally the presence of HMCAS might be considered a negative prognostic sign for the development of extensive brain damage.

Brain↗
PubMed1991

Polylysine activates membrane-bound adenylyl cyclase from Xenopus laevis oocytes through the Gs transducing protein.

1. The activity of the adenylyl cyclase found in the membranes of Xenopus laevis can be affected by polylysine and other polycations. 2. The activity of the catalytic subunit measured with forskolin is inhibited by polylysine and polyarginine at concentrations above 10 microM and by spermine above 3 mM. 3. The adenylyl cyclase activity stimulated by GTP-gamma-S or F- through the stimulatory G protein (Gs) can be increased by polylysine, polyornithine and spermine but not by polyarginine. 4. Polylysine stimulation of Gs dependent activity is due to the increase in the apparent affinity for GTP-gamma-S and to a lowering of the requirement for Mg2+ concentration.

Adenylyl Cyclases↗
PubMed1991

Closure of a tracheoesophageal fistula by bronchoscopic application of fibrin glue and decontamination of the oral cavity.

A tracheoesophageal fistula was successfully closed with a fibrin adhesive applied by means of a fiberoptic bronchoscope, instead of by esophagoscopy. To facilitate closure of the fistula, the technique was combined with decontamination of the oral cavity, to avoid bacterial contamination. The procedure is proposed as an alternative to surgery for critically ill patients.

Administration, Topical↗
PubMed1991

Influence of acetyl-L-carnitine infusion on haemodynamic parameters and survival of circulatory-shock patients.

The clinical use of acetyl carnitine in circulatory shock has its theoretical basis in the ability of this molecule to restore enzyme activity inhibited by hypoxia, acting as an acetyl donor. Moreover the action of carnitine on an injured myocardium encouraged us to examine the clinical effect of this drug during heart failure. A double-blind clinical study was performed in ten Italian intensive care units on 115 patients with septic, cardiac of traumatic shock, by using acetyl-L-carnitine infusion for 12 hours, with a previous single bolus intravenously. The results showed a good response to the drug in terms of blood oxygenation during the course of sepsis and heart failure. The heart rate as well as right atrial pressure decreased significantly in patients with cardiogenic shock. In septic patients systolic and mean arterial pressures increased also. The present data suggests the use of acetyl-L-carnitine as an adjuvant to the commonly used therapy in hypoxic conditions.

Acetylcarnitine↗
PubMed1990

Genetic differences in cystic fibrosis patients with and without pancreatic insufficiency. An Italian collaborative study.

To determine the number and frequency of mutations that occur at the cystic fibrosis locus (CF), we have examined the allele and haplotype frequencies of eight polymorphic DNA markers linked to CF in 163 Italian patients who were sub-divided according to their clinical presentations. The distribution of haplotypes for the tightly linked polymorphisms KM.19 and XV-2c differ significantly between patients with and those without pancreatic insufficiency. The haplotype found most commonly in CF chromosomes occurs much more frequently in pancreatic insufficient than in pancreatic sufficient patients. Among the 19 pancreatic sufficient patients, 6 (31.6%) show at least one copy of the rare KM.19 = 1, XV-2c = 2 haplotype, as against 16 of 138 patients (11.6%) with pancreatic insufficiency. In addition, only 5 pancreatic sufficient patients (26.3%) are homozygous for the common 2.1 haplotype, as compared with 88 patients (63.8%) with pancreatic insufficiency. These findings support the hypothesis of allelic heterogeneity at a single locus in CF and suggest that different mutations underlie the presence or absence of pancreatic insufficiency in this disorders.

Alleles↗