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Biomedical subjects

O Degrossi

Publications and source records attributed to O Degrossi.

At least 19 recordsLinked to original sources
PubMed2000

99mTc-ENS ventilation scintigraphy: preliminary study in human volunteers.

Exogenous natural surfactant (ENS) labeled with (99m)Tc ((99m)Tc-ENS, 900-1110 MBq), a new radiopharmaceutical for ventilation scintigraphy, was nebulized during 3 min to five volunteers. For comparative purposes, (99m)Tc-diethylenetriamine pentaacetic acid (DTPA) was studied in the same way. (99m)Tc-ENS images were of at least the same quality as (99m)Tc-DTPA images. However, in smoking volunteers, the (99m)Tc-DTPA images show some areas that seemed to be not well-ventilated, although these areas appeared well-ventilated when the study was performed with (99m)Tc-ENS. These results suggest that (99m)Tc-ENS can be used for ventilation scintigraphy to allow the observation of some areas that cannot been visualized using (99m)Tc-DTPA as ventilation agent.

Adult↗
PubMed1999

Stable isotope techniques for the detection of Helicobacter pylori infection in clinical practice. 13C-Urea Breath Test in different experimental conditions.

The 13C-UBT has been demonstrated to be a reliable method for the evaluation of Helicobacter pylori infection. The aim of our work is to determine the cut-off point of the 13C-UBT for samples collected as gas or collected in a solution of triethanolamine. For this purpose, patients fasted for at least 6 hours were able to collect basal samples before the administration of 65 mg of 13C-urea solution. Breath samples were taken 10, 30 and 60 minutes after the administration of the labeled solution. All the samples were collected in gas collectors and in glass vials containing 1 ml of a 7% triethanolamine solution. The cut-off points for gas collected samples were established in 4.0/1000, 4.6/1000 and 4.4/1000 for 10, 30 and 60 minutes samples, respectively, while for the samples collected in triethanolamine solution, cut-off points were established in 5.0/1000, for the 10 minutes samples, in 3.5/1000 for the 30 minutes samples and 4.7/1000 for the 60 minutes samples. We found that this test has a sensitivity of 100% and a specificity of 100% for H. pylori detection in both experimental conditions, when multiple breath samples are taken. If we considered only the 30 minutes time, sensitivity and specificity diminish for the gas collected samples. We conclude that the collection of breath samples in triethanolamine solution allows a better differentiation between H. pylori infected and non infected patients than gas collected samples.

Analysis of Variance↗
PubMed1997

MIN 14C UBT: a combination of gastric basal transit and 14C-urea breath test for the detection of Helicobacter pylori infection in human beings.

The purpose of this work is to demonstrate that the 14C-urea breath test (UBT) performed at different times combined with the study of the gastric basal transit, which evaluates the intragastric displacement of a labeled solution under fasting conditions, has the advantage of being representative of the whole stomach surface and constitutes a non-aggressive test for the detection of H. pylori. This test, which has been called MIN 14C UBT, is a modification of the conventional 14C UBT in which low volumes of a solution of 14C-urea together with 99mTc-sulfur colloid are administered. The 99mTc-sulfur colloid is not absorbed in the gastrointestinal tract and has the great advantage of allowing the "visualization" of the transit of the 14C-urea within the gastrointestinal tract. This modification allows the simultaneous determination of the production of the 14CO2 and the place where this process occurs. The results show that there is a good correlation between the images obtained and the breath samples collected. We found that this test has a sensitivity of 98% and a specificity of 96% for H. pylori detection.

Breath Tests↗
PubMed1990

Analysis of left ventricular function by radionuclide ventriculogram in hypertensive patients treated with atenolol.

The myocardial effects of a daily oral dose of atenolol were studied by radionuclide multi-triggered ventriculogram in 10 patients (7 men and 3 women) with mild to moderate essential hypertension, aged 29 to 53 years (mean 43) at rest and during exercise. Before and after two months of treatment with 100 mg/day orally of atenolol, the following variables were recorded: systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), ejection fraction (EF), peak filling rate (PFR) and peak ejection rate (PER). Beta-blockade treatment caused a significant drop in SBP and DBP, both at rest and during exercise; HR slowed down at rest and during exercise. PFR diminished at rest and during exercise. PER was reduced at rest and during exercise (p less than 0.001). No significant changes in EF were observed after treatment with atenolol. In conclusion, atenolol impaired left ventricular relaxation in spite of the drop in blood pressure.

Adult↗
PubMed1987

Role of cardiopulmonary mechanoreceptors in the postural regulation of renin.

To change the stretch on cardiopulmonary mechanoreceptors, large shifts of blood in the capacity space were elicited by tilting and by exerting positive lower body pressure in the tilted position. Twelve volunteers underwent invasive hemodynamic studies and in 10 other subjects cardiac size was determined by radionuclide cardiography. In all 22 subjects tilting caused the expected increase of renin, which was abolished by lower body compression. Decompression caused renin to increase again. Right atrial pressure in invasive studies and end-systolic and end-diastolic counts in noninvasive studies showed a significant and strong negative correlation with renin and norepinephrine levels. Thus, the degree of stretch of the cardiopulmonary mechanoreceptors is a major determinant of reflex regulation of renin release in humans.

Adolescent↗
PubMed1977

In vivo studies on thyroxine and triiodothyronine metabolism in the rat.

The reciprocal effects of loading amounts of thyroxine (T4) or triiodothyronine (T3) on the in vivo deiodination of their 125I-labelled isotopes by the rat were studied. It was found that the deiodination of a tracer amount of [125I]T3 as measured by the 24-h urinary 125iodide was significantly decreased after administration of a loading dose of non-radioactive T4. A similar decrease in deiodination of [125I]T3 was observed following the injection of a T3 load. In experiments in which the deiodination of [125I]T4 was assessed, the effects on this of loading doses of non-radioactive T4 or T3 differed; while stable T4 induced a significant decrease in deiodination of [125I]T4, stable T3 was without effect. The data is in agreement with the view that T4 and T3 share tissue deiodinating sites and that in such a system T4 appears to have a stronger avidity for those sites.

Animals↗